1976, British Journal of Radiology, 49, 244-252
A clinical evaluation of grey-scale ultrasonographyt By K. J. W. Taylor, B.Sc, M.D., Ph.D.,* and V. R. McCready, M.Sc, M.R.C.P., D.M.R.D., F.R.C.R. Department of Nuclear Medicine, Royal Marsden Hospital, Sutton, Surrey {Submitted March, 1975 and in revised form May, 1975)
resolution is maintained in spite of pulsation in the organ being examined. Each interface is recorded in a single position whereas, in a compounded scan, the interface moves during the scan and is registered in different positions. The independence of the amplitude of the backscattered echo on the angle of incidence also raises the possibility that these amplitudes might yield diagnostically useful data on the physical state of the The equipment described in the preceding paper tissue. On theoretical grounds, Fields and Dunn (Hill and Carpenter, 1976) has been under active (1973) proposed that an important site for echo clinical evaluation during the past two years for the production would be interfaces involving media of examination and diagnosis of some 4,000 patients. high bulk moduli. They noted that the supporting The work load has grown rapidly until at present fibrous elements of tissue, such as collagen and the machine is used routinely on a wide variety of elastin, have bulk moduli that may be several orders clinical problems. This has permitted an assessment of magnitude greater than the other components of of the clinical value of grey-scale imaging in addition soft tissue. These therefore could be sites of echo to evaluating both the automatic scanning heads and formation. Mountford and Wells (1972a and 1972b) manual scanning techniques. produced evidence which in retrospect appears to An essential difference between conventional and be consistent with this concept when they quantigrey-scale ultrasonography lies in the selective am- tated the echo amplitudes from cirrhotic and normal plification and display of the low level echoes which livers and found significantly higher levels in the are backscattered from interfaces within soft tissues. cirrhotic livers. Taylor and Milan (unpublished The amplitudes of these echoes are largely independ- work) made similar measurements on the spleen and ent of the angle of incidence. This has two important found that the echo amplitude correlated with the implications: firstly, the advantage gained by com- degree of inflammatory change. Thus, for practical pounding is reduced or eliminated; secondly, the purposes, in the interpretation of a grey-scale uldata on echo amplitude are displayed in various trasonogram, the returned echo pattern can be conshades of grey which depend primarily on the phy- sidered to be a display of the fibrous supporting sical state of the tissue rather than the angle at tissue. Space-occupying lesions are detected because which the beam is incident on the reflector. they replace this normal structure. Donald, McVicar and Brown (1958) introduced At the present time, the manual sector scanner compounding as a scanning technique to improve has been extensively evaluated on most softer orthe probability that, at least once during the course gans. The automatic rectilinear scanner has been of a scan, the beam was at normal incidence to specu- used through a water bath to scan superficial organs lar reflectors. The display of backscattered echoes such as thyroid, testes and breast. These two techon the other hand permits the use of a simple sector niques were found to be adequate for static imaging scan when examining the liver and kidney (Taylor and superior to the spiral scanner in its present form. and Hill, 1975). Simple linear scans were used by The spiral scanner is of some value in ophthalmic Kossoff (1972) for visualizing the breast. A major work although much higher frequencies can be used advantage of such simple techniques is that good with advantage. It can also be used to image the *Present position: Associate Professor of Radiology, Yale heart in real time. However, the present system has University School of Medicine, 333 Cedar Street, New Ha- geometical limitations and, in addition, organ moveven, Conn. 06437. ment has imposed limitations on the clinical value fPart of M.D. Thesis of K. J. W. Taylor, University of of constant depth scans produced by it. London, 1975. ABSTRACT
Recent technical improvements in grey-scale ultrasound imaging have resulted in the visualization of the internal consistency of soft tissues. This permits the diagnosis of diffuse pathology and detection of small space-occupying lesions. The new technique can be used with advantage in the currently accepted obstetrical applications for ultrasound imaging as well as for new non-obstetrical applications. The method has been found to be a most informative, non-intrusive means for investigating hepatobiliary disease and for the differential diagnosis of chronic splenomegaly.
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A clinical evaluation of grey-scale ultrasonography MANUAL SECTOR SCANNING
Hepatobiliary disease The grey-scale technique has been particularly useful in the diagnosis of hepatobiliary disease. Storage scope techniques permit successful differentiation of solid from cystic space-occupying lesions (Ostrum et ah, 1967). For example, ultrasound scanning has been especially valuable in the diagnosis of hepatic abscesses (Wang et al., 1964; Butler and McCarthy, 1969). In the diagnosis of metastatic disease of the liver, conventional (i.e. non-grey-scale) ultrasound is
FIG. 1A.
Diagram to show movement of transducer (T) to produce parasagittal'scan seen in Fig. 1B. P is the right branch of the portal vein, GB is the lumen of the gall-bladder, PV is the pelvi-calyceal system of the right kidney (RK) and D is the diaphragm.
FIG. 1B.
Parasagittal scan showing the anatomy displayed in the schematic diagram.
claimed to produce fewer false positives than isotope examinations (Gros et al., 1972; McCarthy et al., 1970). However, isotope examinations have been reported to be superior to ultrasound in detecting established metastatic disease. On the other hand, in patients with liver involvement which was clinically obvious, McCarthy et al. (1970) were unable to detect any abnormality in 53 per cent of the ultrasound scans, while Leyton et al. (1973) reported a failure rate of 39 per cent in a similar study. These findings were probably due to inaccessibility of some parts of the liver and also to the inability to display the normal detailed anatomy. Using conventional machines, various patterns of echo complexes from metastases have been reported (Holmes, 1966; Holm, 1971; Melki, 1973). Using the grey-scale technique, the liver is seen as a uniform pattern of linear echoes with a constant pattern from small vessels. Metastases are usually seen as areas without vessels, of uneven structure and returning echoes of reduced amplitude. In a small percentage of patients, it is difficult to achieve an acoustic window to all or part of the liver due to air in the transverse colon. Bowel preparation may be required in such patients. The liver is scanned by a series of parasagittal sections as shown schematically in Fig. 1A. The resulting ultrasonogram is shown in Fig. 1B. The liver is seen in longitudinal section, limited above by the right hemi-diaphragm. The lumen of the gallbladder (GB) and the right kidney (RK) are clearly shown. Multiple malignant tumours, seen as circular areas with reduced reflections, replace the normal liver substance in Fig. 2. Part of the right kidney is
FIG. 2. Parasagittal scan through liver and right kidney showing multiple small space-occupying lesions up to 2 cm diameter. Such highly homogenous tumours are seen in the lymphomas.
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seen posteriorly. The grid lines are 2 cm apart so that the smallest detail successfully resolved is about 3 mm. However, it can be difficult to distinguish between a small tumour and blood vessel or bile duct. The appearance of the metastasis may give some indication of its origin (Taylor, 1974). Tumours that are acoustically homogeneous (black) as seen in Fig. 2, are most often due to lymphomas, Hodgkin's disease or colo-rectal primaries. With grey-scale echography, where small echoes are recorded, the differentiation between cysts, abscesses and necrotic tumours requires considerable experience. Benign cysts can usually be distinguished on the basis of their regular walls: the appearance of the A-scan, which shows a virtual absence of returned echoes, indicates little or no cellular debris within the cavity (Howry, 1965). Evidence of surrounding inflammatory changes supports the diagnosis of an abscess cavity. One of the 17 abscesses examined is shown in Fig. 3. A multiloculated cavity can be seen (C) which returned very low-level echoes. There is evidently little attenuation within the lesion, since the more distal echoes have been overamplified by the time gain control (TGC or swept gain). These observations imply that the lesion is fluid filled and contains debris. However, the liver substance returns uneven high level echoes which are believed to be consistent with an inflammatory process. The appearances strongly suggest hydatid disease of the liver (unsuspected in this patient who had never
been out of this country and was clinically remarkably well). The diagnosis was confirmed at laparotomy. • Diffuse liver disease can be diagnosed and benign changes differentiated from malignant ones. The appearances of fatty infiltration (confirmed histologically) are shown in Fig. 4 and are characterized by an even distribution of high-level echoes, frequently associated with dilated veins due to chronic venous congestion. These appearances have been seen in a number of patients who have presented with hepatomegaly and carcinoma of the bronchus. Although liver involvement is simulated on clinical examination, the characteristic ultrasound appearances permit the confident exclusion of malignant involvement. The accuracy of the grey-scale technique in the diagnosis of hepatic disease has been reported by Taylor and Carpenter (1974a). In 120 patients coming to laparotomy or post mortem within three weeks of ultrasound scanning, the ultrasound interpretation was diagnostic in 82 per cent and contributed to the diagnosis in a further 10 per cent. The remaining 8 per cent were false positives or negatives. There is no doubt that the diagnostic accuracy increases with experience of using the technique. During the period of clinical evaluation, some 70 patients were referred with carcinoma of the breast. Liver ultrasonography detected 14 out of 15 cases of liver involvement, for which it was more accurate
FIG. 3. A large abscess cavity (C) can be seen replacing the liver parenchyma. The echoes beyond it are overcompensated for depth gain suggesting a fluid consistency. The liver substance returns uneven high-level echoes consistent with an inflammatory process. The gall-bladder lumen can be seen (G)
FIG. 4. Parasagittal scan through liver and right kidney. The liver returns very high level echoes. These are interspersed by dilated vessels which are distributed in a characteristic pattern. These appearances are typical of fatty infiltration due to chronic venous congestion.
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A clinical evaluation of grey-scale ultrasonography than clinical examination, isotope imaging or elevation of serum alkaline phosphatase. There were three false positive scans out of the remaining 55 cases (Smith et ah, 1975). Ultrasound examination of the liver has become part of the routine work-up on patients with lymphomas and Hodgkin's disease. The method has most value in the advanced stages of these diseases in which liver involvement may occur. However, 50 patients came to a staging laparotomy and splenectomy soon after ultrasound examination and this permitted an accurate assessment of the accuracy of the method with reliable histological confirmation. The ultrasound results correctly predicted liver involvement in three out of five positive wedge biopsies while 42 out of 45 cases of non-involvement were correctly reported (Glees et ah, 1975). Grey-scale ultrasonography has proven to be especially valuable in the non-invasive diagnosis of cholestatic jaundice (Taylor et al., 1974; Taylor and Carpenter, 1974b). In 104 patients referred for investigation of cholestatic jaundice, differentiation between intra- and extrahepatic causes was correctly predicted in 97 per cent. Although the gallbladder is frequently enlarged in extrahepatic biliary obstruction, it may not communicate with the rest of the biliary tree and should therefore not be used as the sole criterion of biliary obstruction. The biliary canaliculi can be visualized and can be seen to be abnormally distended (Fig. 5). In this particular figure, the gall-bladder can be seen and, although it is not abnormally large, it has a rounded distended appearance. With experience, these vessels can
be distinguished from blood vessels but this requires a detailed knowledge of the anatomy of the vascular structures throughout the liver. The common bile duct may be visualized and the precise site of the obstruction determined, especially if care is taken to dispel air from the gut by appropriate preparation. During the last two years, 25 cases of carcinoma of the pancreas have been identified. Spleen Spleen size can be assessed using conventional ultrasonography (Holmes, 1972). To date, no diagnostic echo patterns have been described in association with any particular pathology (Barnett and Morley, 1974). The use of the grey-scale technique has permitted some attempts at the successful differential diagnosis of chronic splenomegaly based on the ultrasound pattern of the splenic consistency. In general, benign causes of chronic splenomegaly are characterized by the return of medium to high level echoes while malignant causes produce very low level echoes. At present, there is insufficient signal to noise ratio in this equipment to permit adequate differentiation between normal and malignant consistencies, and some further technical improvements are required in this and also in the direction of quantitative calibration of grey-scale values. Scans of benign and neoplastic spleens are compared in Figs. 6A and B. The large black spleen seen in Fig. 6A is from a patient with acute leukaemia. A definite pattern, rather like that shown by the placenta, is seen in Fig. 6B which is the spleen of a patient who was suspected of having a lymphoma; a benign cause was correctly predicted by the ultrasound result. GENITO-URINARY SYSTEM
FIG. 5. Parasagittal scan through liver and right kidney. The gallbladder is distended but not abnormally large. There is definite dilatation of the intrahepatic biliary canaliculi (arrowed) which is diagnostic of extrahepatic biliary obstruction.
Kidneys Our equipment has shown relatively little advantage over conventional techniques in the investigation of the urinary tract. This is probably not an inherent defect of the grey-scale imaging approach but stems from the current limitations of the equipment in respect to signal to noise ratio. The pelvicalyceal system is a strong reflector and is well visualized by current techniques (Barnett and Morley, 1974) whereas the cortex returns echoes of too low an amplitude to be registered. However, the use of simple sector scanning techniques permits dilation of the renal pelvis to be displayed (Taylor and Hill, 1975); this sign of minimal hydronephrosis has been observed even before the intravenous pyelogram became abnormal. Using conventional ultrasound equipment, some renal tumours may be
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FIG. 6A.
Transverse scan of spleen in chronic lymphatic leukaemia. The spleen is virtually echo free although a few deep echoes may be displayed in patients who have been treated. FIG. 7. Parasagittal scan through the abdomen of two-year-old child. A large tumour mass with a homogeneous upper pole fills the abdomen. Posteriorly, the vertebral column is seen where the ultrasound beam has transversed the intervertebral discs.
FIG. 6B.
Transverse scan of spleen (S) which returns a fine structure throughout. A splenic artery (a) can be seen. V is the vertebra. This is characteristic of benign splenomegaly.
misdiagnosed as cysts due to their extreme homogeneity. The grey-scale technique renders this less likely since low-level echoes are amplified and some internal structure is always observed in solid tumours. A Wilms tumour is shown in Fig. 7. It filled the left half of the abdomen in a two-year-old child. Although the upper pole of the tumour is highly homogeneous, there is a definite structure in most of the tumour material. As normally occurs in infants, the ultrasound beam has passed between the vertebrae. Bladder Again, the addition of grey-scale adds little to the data that may be obtained by conventional scanning
FIG. 8. Transverse scan through bladder at level of symphysis pubis. The cavity (B) is the bladder contents and the lumen is encroached by a sessile tumour on the indurated posterior wall of the bladder. Homogenous tumour is seen spreading out from the base of the mass towards the left side of the pelvis.
(Barnett and Morley, 1971; 1972), and indeed, debris in the urine may be displayed to such an extent to interfere with the clinical value of the scan. However, the ability to register the whole range of echoes in a single scan implies that the bladder contents are displayed on the same scan which shows the degree of extravesical spread of a bladder tumour. A transverse scan of the bladder is shown in Fig. 8 with a tumour on the left posterior wall, and
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FIG. 9. Transverse scan through bladder (B) at the level of the symphysis pubis. The posterior wall of the bladder is displaced forwards by a solid ovarian tumour (T) which proved to be a metastatic melanoma.
FIG. 10. Longitudinal scan of gravid uterus showing fetus in vertex presentation. The placenta (P) has a definite structure to it and is seen anterior to the fetal head. It can be traced round the head onto the posterior wall of the uterus. The inferior edge of the placenta is irregular and there is probable haematoma between it and the internal os (arrowed).
neoplastic material spreading out into the left side of the pelvis. There is induration of the bladder wall which supported the conclusion that the tumour was malignant.
et ah, 1974). The technique therefore permits the in utero detection of congenital abnormalities. A gravid uterus is shown in Fig. 10 in which the fetal parts are well defined and the placental relation to the internal os can be assessed precisely.
Ovary Grey-scale techniques display solid tumour material and therefore it is easier to differentiate between solid and cystic ovarian masses; this is of particular value in the diagnosis of cystaden carcinoma of the ovary. An ovarian tumour, seen in Fig. 9, has a definite pattern throughout it. This patient was a 19-year-old female with widespread metastatic disease from a melanoma. Following the development of urinary incontinence only one physician out of four felt a pelvic mass in the patient. The ultrasound examination displayed the tumour clearly and the low-level echoes showed that it was solid rather than cystic. Obstetrics
Conventional ultrasound permits highly accurate placental localization and determination of fetal maturity. For biparietal estimations, the conventional scan has a positive advantage since the contour of the head is displayed particularly clearly. However, the use of the grey-scale technique, which displays the substance of the placenta, makes placental localization more reliable even in less experienced hands. The detailed fetal anatomy which may be displayed by this technique has been strikingly shown by Kossoff and his colleagues (Kossoff, 1972; Kossoff and Garrett, 1972; Kossoff
RECTILINEAR SCANNER
Breast Although ultrasound appears to be an attractive alternative to ionising radiation for the detection of lumps in the breast, a tomographic technique is unsuited to the mass screening of healthy patients. The 100-200 sections required per patient would pose practical difficulties in execution and interpretation. Grey-scale ultrasonography has been used successfully to differentiate adenomas, cysts and carcinomas (Kosoff, 1974). However, in the practical management of a patient, a breast lump is nearly always excised or aspirated, enabling the nature of the mass to be established definitively. Ultrasound imaging may be of value as a radiationfree technique to follow-up lumps which have not been excised. Thyroid Grey-scale ultrasonography has been successfully used in the examination of the thyroid to differentiate cold areas on the isotope scan due to adenomas, cysts and malignancies (Taylor and McCready, 1975). The display of normal glandular tissue is essential for the reliable differentiation of benign and malignant masses of the thyroid. Malignant
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tissue in the thyroid is characterized by returning echoes of lower amplitude than those from normal tissue (Crocker et ah, 1974). Adenomas usually are seen as circumscribed areas with high level echoes. Fluid-containing areas produce no echoes while a typical scan showing a cyst involving the anterior aspect of the left lobe is seen in Fig. 11. Testis Testicular scanning has been reported using conventional ultrasound equipment (Miskin and Bain, 1974) but the inability to define the normal consistency of the organ precludes recognition of any small impalpable tumour. The rectilinear scanner, together with a grey-scale technique, enables small tumours and other lesions to be seen. A small tumour in the left testis of a patient who presented with a mediastinal teratoma is shown in Fig. 12. The clinical problem in the management of this patient was to establish whether the mediastinum was the primary site of the tumour or whether this was metastatic from an occult tumour in the testis. The ultrasonogram shows a small defect in the edge of the left testis, which solved this problem.
results have become useful clinically has resulted in little time being left to fully assess the automatic scanning methods. Nevertheless the constant depth and spiral scans have not realized their initial promise. Automatic rectilinear scans of the thyroid are likely to be especially useful as a complementary investigation to the isotope scan. The rectilinear breast scans show promise but with the quality attainable with mammograms and xeroradiography it seems that our limited resources should be concentrated on the other soft tissues where alternative investigations are poor or absent. The outstanding improvements in diagnosis have been in the area of liver disease. Here, fine jdetailed anatomy is visible throughout the liver so that vessels and other structures as small as 3 mm diameter can be seen, making the diagnosis of early metastases and other space occupying lesions possible. The ability to see small biliary ducts is especially useful in the investigation of cholestatic jaundice where ultrasound fills a previous hiatus in our diagnostic capability. The fine anatomy displayed by this technique, requires for successful interpretation, a detailed knowledge of the anatomy and pathology of the
DISCUSSION
The recent availability of grey-scale high resolution ultrasonography has greatly improved the diagnostic capabilities of this technique. The results presented indicate our preliminary assessment of where such techniques are useful in clinical diagnosis. However, in such a short time only relatively little experience has been gathered and it is obvious both that the diagnostic accuracy will improve further and that the range of worthwhile applications for both the manual and automatic scanning techniques will increase. The initial interest and concentration on automatic scanning techniques has been overshadowed by the quality and diagnostic value of the manual grey-scale sector scans. The speed with which the
FIG. 11. Transverse scan of thyroid. The trachea appears black (T) and the lateral lobes of the thyroid lie on either side of it. There is a 2 cm cyst (A) in the left lateral lobe. The common carotid artery (arrowed) is just resolved.
FIG. 12. Transverse scan both testes. There is a small defect due to an occult tumour (arrowed) in the margin of the left testis.
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A clinical evaluation of grey-scale ultrasonography liver as revealed by grey-scale ultrasonography. The GLEES, J., TAYLOR, K. J. W., GAZET, J. C , and PECKHAM M. J., 1975. Superior accuracy of grey-scale ultrasonodiagnosis of necrotic tumour, cysts and abscesses graphy of liver and spleen in Hodgkin's disease and requires attention to features such as the number lymphomas compared with isotope scans. Clinical Radiology (in press). present, the shape of the lesion and its internal strucGROS, C , WALTER, J. P., and PARISOT, B., 1972. Echoture. Thus, although considerable experience is graphy in liver pathology. Journal de Radiologie d'elecrequired to make a confident diagnosis, the method trologie, 53, 1AQ-1AX. is potentially so accurate that time spent in training HILL, C. R., and CARPENTER, D. A., 1976. Ultrasonic Echo imaging of tissue: Instrumentation. British Journal of is worthwhile. Radiology 49, 238-243. The spleen is an organ which has proved difficult HOLM, H. H., 1971. Ultrasonic scanning in the diagnosis of space-occupying lesions of the upper abdomen. British to assess by plain radiography or isotope methods. Journal of Radiology, 44, 24—36. Our preliminary work would indicate already that HOLMES, J. H., 1966. Ultrasonic diagnosis of liver disease. In Diagnostic Ultrasound, eds. C. C. Grossman, J. H. ultrasound grey-scale techniques will be of great Holmes, C. Joyner and E. W. Purnell, pp. 249-265 value even in diffuse diseases. Very encouraging (Plenum Press, New York). results have been found in the genitourinary system 1972. Ultrasonic studies of the abdomen, p. 61 (Colorado; University of Colorado School of Medicine). although grey-scale techniques have less advantage HOWRY, D. H., 1965. A brief atlas of diagnostic ultrasonic over conventional scanners. However, the high resoradiologie results. Radiologie Clinics of North America, 3, 433-452. lution and intratumour details visualized indicate that better equipment yields better quality pictures KOSSOFF, G., 1972. Improved techniques in ultrasonic cross-sectional echography. Ultrasonics, 10, 221-229. even if the overall diagnostic accuracy is not mar1974. Display techniques in ultrasound pulse echo investigations: A review. Journal of Clinical Ultrasound, kedly improved. 2, 61-72. Of course conventional techniques have been KOSSOFF, G., and GARRETT, W. J., 1972. Ultrasonic film highly successful in the obstetrics field for many echography in gynecology and obstetrics. Obstetrics and Gynecology, 40, 299-305. years. The grey-scale technique makes placental KOSSOFF, G., GARRETT, W. J., and RADAVANOVICH, G., 1974. identification considerably easier even in less exUltrasonic atlas of normal brain of infant. Ultrasound in Medicine and Biology, 1, 259-266. perienced hands. In this field the quality of the scans obtained by Kossoff and his team, using grey LEYTON, B., HALPERN, S., LEOPOLD, G., and HAGEN, S., 1973. Correlation of ultrasound and colloid scintiscan scale coupled to an automatic scanner, would suggest studies of the normal and diseased liver. Journal of Nuclear Medicine, 14, 27-33. that future departments are likely to have a series of C. F., DAVIES, E. R., WELLS, P. N. T., Ross, specialized ultrasound scanners for specific organs. MCCARTHY, F. G. M., FOLLET, D. H., MUIR, K. M., and READ, In some applications, ultrasound techniques may A. E. A., 1970. A comparison of ultrasonic and isotopic scanning in the diagnosis of liver disease. British Journal replace current intrusive imaging techniques but in of Radiology, 43,100-109. general they offer extra information which comple- MELKI, G., 1973. Ultrasonic patterns of tumours of the ments other diagnostic techniques. liver. Journal of Clinical Ultrasound, 1, 306-314. MISKIN, M., and BAIN, J., 1974. B mode ultrasonic ex-
amination of the testis. Journal of Clinical Ultrasound, 2, 307-311.
ACKNOWLEDGMENT
We wish to acknowledge financial support by the Department of Health and Social Security for the development of the instrumentation used in this study.
MOUNTFORD, R. A., and WELLS, P. N. T., 1972a. Ultrasonic
liver scanning: the quantitative analysis of the normal A scan. Physics in Medicine and Biology, 17, 14—25. 1972b. Ultrasonic liver scanning: The A scan in the normal and in cirrhotics. Physics in Medicine and biology 17,261-269.
REFERENCES BARNETT, E., and MORLEY, P., 1971. Ultrasound in the
investigation of space-occupying lesion of the urinary OSTRUM, B. J., GOLDBERG, B. B., and ISARD, H. J., 1967. A mode ultrasound differentiation of soft tissue masses. tract. British Journal of Radiology, 44, 733-742. Radiology, 88, 745-749. 1972. Diagnostic ultrasound in renal disease. British SMITH, I., TAYLOR, K. J. W., MCCREADY, V. R., and Medical Bulletin, 28,196-199. POWLES, T., 1976. Comparison of grey-scale ultrasound 1974. Urinary tract. In Abdominal Echography-Ultrasound in the Diagnosis of Abdominal Conditions, pp. 53- with other methods for detection of liver metastases from carcinoma of breast (Submitted for publication). 69 (Butterworths, London). BUTLER, T. J., and MCCARTHY, C. F., 1969. Pyogenic liver TAYLOR, K. J. W., 1974. Letter. Journal of Clinical Ultrasound, 2, 7A-16. abscess. Gut, 10, 389-399. TAYLOR, K. J. W., and CARPENTER, D. A., 1974a. Com-
CROCKER, E. F.MCLAUGHLIN, A. F., KOSSOFF, G., and
parison of radioisotope and ultrasound examination in the investigation of hepatobiliary disease. In Ultrasound in Medicine, Vol. 1. Ed. D. White, pp. 159-167 (Plenum Press, New York). 1974b. Grey-scale ultrasonography in the investigation of obstructive jaundice. Lancet, 11, 586-7.
JELLINS, J., 1974. The grey-scale echographic appearances of thyroid malignancy. Journal of Clinical Ultrasound, 2,305-306. DONALD, I., MCVICAR, J., and BROWN, T. G., 1958.
Investigation of abdominal masses by pulsed ultrasound. Lancet, 1,1188-1194. FIELDS, S., and DUNN, F., 1973. Correlation of echographic
TAYLOR, K. J. W., CARPENTER, D. A., and MCCREADY,
visualizability of tissue with biological composition and physiological state. Journal Acoustic Society of America, 54,809-812. 251
V. R., 1974. Ultrasound and scintigraphy in the differential diagnosis of obstructive jaundice. Journal of Clinical Ultrasound, 2, 105-116.
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TAYLOR, K. J. W., and HILL, C. R., 1975. Scanning tech-
niques in grey-scale ultrasonography. British Journal of Radiology, 48, 918-920.
value of ultrasonic diagnosis of liver abscess; a report of 218 cases. Chinese Medical Journal, 83, 133-140.
TAYLOR, K. J. W., and MCCREADY, V. R., 1975. Compari-
son of radioisotope and ultrasound scans of the thyroid.
Book review Brain Scintigraphy. By Lourens Penning and Dov Front, pp. xi+384, 1975 (Amsterdam, Excerpta Medica), Dfl. 148.00. There is one strange thing about this excellent book. Apart from their names, it is difficult to discover any information about the authors. Both will be known to all of us who are interested in cerebral scanning from their published works. Professor Penning is a neuroradiologist at the University Hospital of Groningen, and Professor Front is a neurologist working in the Nuclear Medicine Department of the University of Haifa. That both authors are very clinically orientated is one of the chief delights of this book. Indeed, the title is misleading, for this is far more than a text-book of brain scintigraphy. The book is divided into sections, and each section is sub-divided into the written text and the illustrations. This subdivision can be disturbing to one's concentration, requiring a search some 10 to 20 pages farther on for the correct illustration. Even with this arrangement there is a considerable amount of empty space between the illustrations which could have been used to increase the size of the robot pictures which are rather small for those not used to this technique. However, these are minor criticisms, and considering the profusion of pictures, the layout and format may have been inevitable. The quality of the pictures is superb, and a nice mixture of other neuroradiological techniques is included. The first section of the book deals with the normal scintigram, technique and normal anatomical details. The technique adopted is exhaustive, and one doubts if it could be practised in many departments in the United Kingdom. Rapid sequential pictures up to three per second are taken
by Robot 35 mm camera and followed by Polaroid film every 20 seconds, and at increasing intervals up to 30 minutes. Static scans are taken at one hour and may be repeated at three hours. This data may be increased in certain cases by an intra-arterial injection of isotope. Obviously, such a technique requires at least one gamma-camera dedicated totally to neuroradiology. There is, however, no doubt that this technique yields a lot of information in the author's hands. The second section deals with the abnormal scintigram. It contains a whole mine of information about cerebral tumours, infection, trauma, vascular lesions and a lot of other conditions—clearly presented and with excellent illustrations. The value of dynamic and sequential studies in the differential diagnosis of tumour histology is well discussed. The third section deals with CSF flow studied by cisternography—the problems of normal pressure hydrocephalus, of CSF leaks and various cystic conditions are all dealt with and the authors' considerable experience in this still developing area is again illustrated well and supported by line-drawings. The book, as a whole, gives a comprehensive and detailed account of cerebral scintigraphy including isotope arteriography, sequential and late static studies. There is an extensive list of references. It is well produced and a credit to the publishers—it even remains open at any chosen page. The price is high—approximately £30. Nevertheless, even if this sum is beyond the pocket of some individuals, this book is a must for every department of neuroradiology and of nuclear medicine.
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A clinical evaluation of grey-scale ultrasonographyt By K. J. W. Taylor, B.Sc, M.D., Ph.D.,* and V. R. McCready, M.Sc, M.R.C.P., D.M.R.D., F.R.C.R. Department of Nuclear Medicine, Royal Marsden Hospital, Sutton, Surrey {Submitted March, 1975 and in revised form May, 1975)
resolution is maintained in spite of pulsation in the organ being examined. Each interface is recorded in a single position whereas, in a compounded scan, the interface moves during the scan and is registered in different positions. The independence of the amplitude of the backscattered echo on the angle of incidence also raises the possibility that these amplitudes might yield diagnostically useful data on the physical state of the The equipment described in the preceding paper tissue. On theoretical grounds, Fields and Dunn (Hill and Carpenter, 1976) has been under active (1973) proposed that an important site for echo clinical evaluation during the past two years for the production would be interfaces involving media of examination and diagnosis of some 4,000 patients. high bulk moduli. They noted that the supporting The work load has grown rapidly until at present fibrous elements of tissue, such as collagen and the machine is used routinely on a wide variety of elastin, have bulk moduli that may be several orders clinical problems. This has permitted an assessment of magnitude greater than the other components of of the clinical value of grey-scale imaging in addition soft tissue. These therefore could be sites of echo to evaluating both the automatic scanning heads and formation. Mountford and Wells (1972a and 1972b) manual scanning techniques. produced evidence which in retrospect appears to An essential difference between conventional and be consistent with this concept when they quantigrey-scale ultrasonography lies in the selective am- tated the echo amplitudes from cirrhotic and normal plification and display of the low level echoes which livers and found significantly higher levels in the are backscattered from interfaces within soft tissues. cirrhotic livers. Taylor and Milan (unpublished The amplitudes of these echoes are largely independ- work) made similar measurements on the spleen and ent of the angle of incidence. This has two important found that the echo amplitude correlated with the implications: firstly, the advantage gained by com- degree of inflammatory change. Thus, for practical pounding is reduced or eliminated; secondly, the purposes, in the interpretation of a grey-scale uldata on echo amplitude are displayed in various trasonogram, the returned echo pattern can be conshades of grey which depend primarily on the phy- sidered to be a display of the fibrous supporting sical state of the tissue rather than the angle at tissue. Space-occupying lesions are detected because which the beam is incident on the reflector. they replace this normal structure. Donald, McVicar and Brown (1958) introduced At the present time, the manual sector scanner compounding as a scanning technique to improve has been extensively evaluated on most softer orthe probability that, at least once during the course gans. The automatic rectilinear scanner has been of a scan, the beam was at normal incidence to specu- used through a water bath to scan superficial organs lar reflectors. The display of backscattered echoes such as thyroid, testes and breast. These two techon the other hand permits the use of a simple sector niques were found to be adequate for static imaging scan when examining the liver and kidney (Taylor and superior to the spiral scanner in its present form. and Hill, 1975). Simple linear scans were used by The spiral scanner is of some value in ophthalmic Kossoff (1972) for visualizing the breast. A major work although much higher frequencies can be used advantage of such simple techniques is that good with advantage. It can also be used to image the *Present position: Associate Professor of Radiology, Yale heart in real time. However, the present system has University School of Medicine, 333 Cedar Street, New Ha- geometical limitations and, in addition, organ moveven, Conn. 06437. ment has imposed limitations on the clinical value fPart of M.D. Thesis of K. J. W. Taylor, University of of constant depth scans produced by it. London, 1975. ABSTRACT
Recent technical improvements in grey-scale ultrasound imaging have resulted in the visualization of the internal consistency of soft tissues. This permits the diagnosis of diffuse pathology and detection of small space-occupying lesions. The new technique can be used with advantage in the currently accepted obstetrical applications for ultrasound imaging as well as for new non-obstetrical applications. The method has been found to be a most informative, non-intrusive means for investigating hepatobiliary disease and for the differential diagnosis of chronic splenomegaly.
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A clinical evaluation of grey-scale ultrasonography MANUAL SECTOR SCANNING
Hepatobiliary disease The grey-scale technique has been particularly useful in the diagnosis of hepatobiliary disease. Storage scope techniques permit successful differentiation of solid from cystic space-occupying lesions (Ostrum et ah, 1967). For example, ultrasound scanning has been especially valuable in the diagnosis of hepatic abscesses (Wang et al., 1964; Butler and McCarthy, 1969). In the diagnosis of metastatic disease of the liver, conventional (i.e. non-grey-scale) ultrasound is
FIG. 1A.
Diagram to show movement of transducer (T) to produce parasagittal'scan seen in Fig. 1B. P is the right branch of the portal vein, GB is the lumen of the gall-bladder, PV is the pelvi-calyceal system of the right kidney (RK) and D is the diaphragm.
FIG. 1B.
Parasagittal scan showing the anatomy displayed in the schematic diagram.
claimed to produce fewer false positives than isotope examinations (Gros et al., 1972; McCarthy et al., 1970). However, isotope examinations have been reported to be superior to ultrasound in detecting established metastatic disease. On the other hand, in patients with liver involvement which was clinically obvious, McCarthy et al. (1970) were unable to detect any abnormality in 53 per cent of the ultrasound scans, while Leyton et al. (1973) reported a failure rate of 39 per cent in a similar study. These findings were probably due to inaccessibility of some parts of the liver and also to the inability to display the normal detailed anatomy. Using conventional machines, various patterns of echo complexes from metastases have been reported (Holmes, 1966; Holm, 1971; Melki, 1973). Using the grey-scale technique, the liver is seen as a uniform pattern of linear echoes with a constant pattern from small vessels. Metastases are usually seen as areas without vessels, of uneven structure and returning echoes of reduced amplitude. In a small percentage of patients, it is difficult to achieve an acoustic window to all or part of the liver due to air in the transverse colon. Bowel preparation may be required in such patients. The liver is scanned by a series of parasagittal sections as shown schematically in Fig. 1A. The resulting ultrasonogram is shown in Fig. 1B. The liver is seen in longitudinal section, limited above by the right hemi-diaphragm. The lumen of the gallbladder (GB) and the right kidney (RK) are clearly shown. Multiple malignant tumours, seen as circular areas with reduced reflections, replace the normal liver substance in Fig. 2. Part of the right kidney is
FIG. 2. Parasagittal scan through liver and right kidney showing multiple small space-occupying lesions up to 2 cm diameter. Such highly homogenous tumours are seen in the lymphomas.
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seen posteriorly. The grid lines are 2 cm apart so that the smallest detail successfully resolved is about 3 mm. However, it can be difficult to distinguish between a small tumour and blood vessel or bile duct. The appearance of the metastasis may give some indication of its origin (Taylor, 1974). Tumours that are acoustically homogeneous (black) as seen in Fig. 2, are most often due to lymphomas, Hodgkin's disease or colo-rectal primaries. With grey-scale echography, where small echoes are recorded, the differentiation between cysts, abscesses and necrotic tumours requires considerable experience. Benign cysts can usually be distinguished on the basis of their regular walls: the appearance of the A-scan, which shows a virtual absence of returned echoes, indicates little or no cellular debris within the cavity (Howry, 1965). Evidence of surrounding inflammatory changes supports the diagnosis of an abscess cavity. One of the 17 abscesses examined is shown in Fig. 3. A multiloculated cavity can be seen (C) which returned very low-level echoes. There is evidently little attenuation within the lesion, since the more distal echoes have been overamplified by the time gain control (TGC or swept gain). These observations imply that the lesion is fluid filled and contains debris. However, the liver substance returns uneven high level echoes which are believed to be consistent with an inflammatory process. The appearances strongly suggest hydatid disease of the liver (unsuspected in this patient who had never
been out of this country and was clinically remarkably well). The diagnosis was confirmed at laparotomy. • Diffuse liver disease can be diagnosed and benign changes differentiated from malignant ones. The appearances of fatty infiltration (confirmed histologically) are shown in Fig. 4 and are characterized by an even distribution of high-level echoes, frequently associated with dilated veins due to chronic venous congestion. These appearances have been seen in a number of patients who have presented with hepatomegaly and carcinoma of the bronchus. Although liver involvement is simulated on clinical examination, the characteristic ultrasound appearances permit the confident exclusion of malignant involvement. The accuracy of the grey-scale technique in the diagnosis of hepatic disease has been reported by Taylor and Carpenter (1974a). In 120 patients coming to laparotomy or post mortem within three weeks of ultrasound scanning, the ultrasound interpretation was diagnostic in 82 per cent and contributed to the diagnosis in a further 10 per cent. The remaining 8 per cent were false positives or negatives. There is no doubt that the diagnostic accuracy increases with experience of using the technique. During the period of clinical evaluation, some 70 patients were referred with carcinoma of the breast. Liver ultrasonography detected 14 out of 15 cases of liver involvement, for which it was more accurate
FIG. 3. A large abscess cavity (C) can be seen replacing the liver parenchyma. The echoes beyond it are overcompensated for depth gain suggesting a fluid consistency. The liver substance returns uneven high-level echoes consistent with an inflammatory process. The gall-bladder lumen can be seen (G)
FIG. 4. Parasagittal scan through liver and right kidney. The liver returns very high level echoes. These are interspersed by dilated vessels which are distributed in a characteristic pattern. These appearances are typical of fatty infiltration due to chronic venous congestion.
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A clinical evaluation of grey-scale ultrasonography than clinical examination, isotope imaging or elevation of serum alkaline phosphatase. There were three false positive scans out of the remaining 55 cases (Smith et ah, 1975). Ultrasound examination of the liver has become part of the routine work-up on patients with lymphomas and Hodgkin's disease. The method has most value in the advanced stages of these diseases in which liver involvement may occur. However, 50 patients came to a staging laparotomy and splenectomy soon after ultrasound examination and this permitted an accurate assessment of the accuracy of the method with reliable histological confirmation. The ultrasound results correctly predicted liver involvement in three out of five positive wedge biopsies while 42 out of 45 cases of non-involvement were correctly reported (Glees et ah, 1975). Grey-scale ultrasonography has proven to be especially valuable in the non-invasive diagnosis of cholestatic jaundice (Taylor et al., 1974; Taylor and Carpenter, 1974b). In 104 patients referred for investigation of cholestatic jaundice, differentiation between intra- and extrahepatic causes was correctly predicted in 97 per cent. Although the gallbladder is frequently enlarged in extrahepatic biliary obstruction, it may not communicate with the rest of the biliary tree and should therefore not be used as the sole criterion of biliary obstruction. The biliary canaliculi can be visualized and can be seen to be abnormally distended (Fig. 5). In this particular figure, the gall-bladder can be seen and, although it is not abnormally large, it has a rounded distended appearance. With experience, these vessels can
be distinguished from blood vessels but this requires a detailed knowledge of the anatomy of the vascular structures throughout the liver. The common bile duct may be visualized and the precise site of the obstruction determined, especially if care is taken to dispel air from the gut by appropriate preparation. During the last two years, 25 cases of carcinoma of the pancreas have been identified. Spleen Spleen size can be assessed using conventional ultrasonography (Holmes, 1972). To date, no diagnostic echo patterns have been described in association with any particular pathology (Barnett and Morley, 1974). The use of the grey-scale technique has permitted some attempts at the successful differential diagnosis of chronic splenomegaly based on the ultrasound pattern of the splenic consistency. In general, benign causes of chronic splenomegaly are characterized by the return of medium to high level echoes while malignant causes produce very low level echoes. At present, there is insufficient signal to noise ratio in this equipment to permit adequate differentiation between normal and malignant consistencies, and some further technical improvements are required in this and also in the direction of quantitative calibration of grey-scale values. Scans of benign and neoplastic spleens are compared in Figs. 6A and B. The large black spleen seen in Fig. 6A is from a patient with acute leukaemia. A definite pattern, rather like that shown by the placenta, is seen in Fig. 6B which is the spleen of a patient who was suspected of having a lymphoma; a benign cause was correctly predicted by the ultrasound result. GENITO-URINARY SYSTEM
FIG. 5. Parasagittal scan through liver and right kidney. The gallbladder is distended but not abnormally large. There is definite dilatation of the intrahepatic biliary canaliculi (arrowed) which is diagnostic of extrahepatic biliary obstruction.
Kidneys Our equipment has shown relatively little advantage over conventional techniques in the investigation of the urinary tract. This is probably not an inherent defect of the grey-scale imaging approach but stems from the current limitations of the equipment in respect to signal to noise ratio. The pelvicalyceal system is a strong reflector and is well visualized by current techniques (Barnett and Morley, 1974) whereas the cortex returns echoes of too low an amplitude to be registered. However, the use of simple sector scanning techniques permits dilation of the renal pelvis to be displayed (Taylor and Hill, 1975); this sign of minimal hydronephrosis has been observed even before the intravenous pyelogram became abnormal. Using conventional ultrasound equipment, some renal tumours may be
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FIG. 6A.
Transverse scan of spleen in chronic lymphatic leukaemia. The spleen is virtually echo free although a few deep echoes may be displayed in patients who have been treated. FIG. 7. Parasagittal scan through the abdomen of two-year-old child. A large tumour mass with a homogeneous upper pole fills the abdomen. Posteriorly, the vertebral column is seen where the ultrasound beam has transversed the intervertebral discs.
FIG. 6B.
Transverse scan of spleen (S) which returns a fine structure throughout. A splenic artery (a) can be seen. V is the vertebra. This is characteristic of benign splenomegaly.
misdiagnosed as cysts due to their extreme homogeneity. The grey-scale technique renders this less likely since low-level echoes are amplified and some internal structure is always observed in solid tumours. A Wilms tumour is shown in Fig. 7. It filled the left half of the abdomen in a two-year-old child. Although the upper pole of the tumour is highly homogeneous, there is a definite structure in most of the tumour material. As normally occurs in infants, the ultrasound beam has passed between the vertebrae. Bladder Again, the addition of grey-scale adds little to the data that may be obtained by conventional scanning
FIG. 8. Transverse scan through bladder at level of symphysis pubis. The cavity (B) is the bladder contents and the lumen is encroached by a sessile tumour on the indurated posterior wall of the bladder. Homogenous tumour is seen spreading out from the base of the mass towards the left side of the pelvis.
(Barnett and Morley, 1971; 1972), and indeed, debris in the urine may be displayed to such an extent to interfere with the clinical value of the scan. However, the ability to register the whole range of echoes in a single scan implies that the bladder contents are displayed on the same scan which shows the degree of extravesical spread of a bladder tumour. A transverse scan of the bladder is shown in Fig. 8 with a tumour on the left posterior wall, and
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FIG. 9. Transverse scan through bladder (B) at the level of the symphysis pubis. The posterior wall of the bladder is displaced forwards by a solid ovarian tumour (T) which proved to be a metastatic melanoma.
FIG. 10. Longitudinal scan of gravid uterus showing fetus in vertex presentation. The placenta (P) has a definite structure to it and is seen anterior to the fetal head. It can be traced round the head onto the posterior wall of the uterus. The inferior edge of the placenta is irregular and there is probable haematoma between it and the internal os (arrowed).
neoplastic material spreading out into the left side of the pelvis. There is induration of the bladder wall which supported the conclusion that the tumour was malignant.
et ah, 1974). The technique therefore permits the in utero detection of congenital abnormalities. A gravid uterus is shown in Fig. 10 in which the fetal parts are well defined and the placental relation to the internal os can be assessed precisely.
Ovary Grey-scale techniques display solid tumour material and therefore it is easier to differentiate between solid and cystic ovarian masses; this is of particular value in the diagnosis of cystaden carcinoma of the ovary. An ovarian tumour, seen in Fig. 9, has a definite pattern throughout it. This patient was a 19-year-old female with widespread metastatic disease from a melanoma. Following the development of urinary incontinence only one physician out of four felt a pelvic mass in the patient. The ultrasound examination displayed the tumour clearly and the low-level echoes showed that it was solid rather than cystic. Obstetrics
Conventional ultrasound permits highly accurate placental localization and determination of fetal maturity. For biparietal estimations, the conventional scan has a positive advantage since the contour of the head is displayed particularly clearly. However, the use of the grey-scale technique, which displays the substance of the placenta, makes placental localization more reliable even in less experienced hands. The detailed fetal anatomy which may be displayed by this technique has been strikingly shown by Kossoff and his colleagues (Kossoff, 1972; Kossoff and Garrett, 1972; Kossoff
RECTILINEAR SCANNER
Breast Although ultrasound appears to be an attractive alternative to ionising radiation for the detection of lumps in the breast, a tomographic technique is unsuited to the mass screening of healthy patients. The 100-200 sections required per patient would pose practical difficulties in execution and interpretation. Grey-scale ultrasonography has been used successfully to differentiate adenomas, cysts and carcinomas (Kosoff, 1974). However, in the practical management of a patient, a breast lump is nearly always excised or aspirated, enabling the nature of the mass to be established definitively. Ultrasound imaging may be of value as a radiationfree technique to follow-up lumps which have not been excised. Thyroid Grey-scale ultrasonography has been successfully used in the examination of the thyroid to differentiate cold areas on the isotope scan due to adenomas, cysts and malignancies (Taylor and McCready, 1975). The display of normal glandular tissue is essential for the reliable differentiation of benign and malignant masses of the thyroid. Malignant
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tissue in the thyroid is characterized by returning echoes of lower amplitude than those from normal tissue (Crocker et ah, 1974). Adenomas usually are seen as circumscribed areas with high level echoes. Fluid-containing areas produce no echoes while a typical scan showing a cyst involving the anterior aspect of the left lobe is seen in Fig. 11. Testis Testicular scanning has been reported using conventional ultrasound equipment (Miskin and Bain, 1974) but the inability to define the normal consistency of the organ precludes recognition of any small impalpable tumour. The rectilinear scanner, together with a grey-scale technique, enables small tumours and other lesions to be seen. A small tumour in the left testis of a patient who presented with a mediastinal teratoma is shown in Fig. 12. The clinical problem in the management of this patient was to establish whether the mediastinum was the primary site of the tumour or whether this was metastatic from an occult tumour in the testis. The ultrasonogram shows a small defect in the edge of the left testis, which solved this problem.
results have become useful clinically has resulted in little time being left to fully assess the automatic scanning methods. Nevertheless the constant depth and spiral scans have not realized their initial promise. Automatic rectilinear scans of the thyroid are likely to be especially useful as a complementary investigation to the isotope scan. The rectilinear breast scans show promise but with the quality attainable with mammograms and xeroradiography it seems that our limited resources should be concentrated on the other soft tissues where alternative investigations are poor or absent. The outstanding improvements in diagnosis have been in the area of liver disease. Here, fine jdetailed anatomy is visible throughout the liver so that vessels and other structures as small as 3 mm diameter can be seen, making the diagnosis of early metastases and other space occupying lesions possible. The ability to see small biliary ducts is especially useful in the investigation of cholestatic jaundice where ultrasound fills a previous hiatus in our diagnostic capability. The fine anatomy displayed by this technique, requires for successful interpretation, a detailed knowledge of the anatomy and pathology of the
DISCUSSION
The recent availability of grey-scale high resolution ultrasonography has greatly improved the diagnostic capabilities of this technique. The results presented indicate our preliminary assessment of where such techniques are useful in clinical diagnosis. However, in such a short time only relatively little experience has been gathered and it is obvious both that the diagnostic accuracy will improve further and that the range of worthwhile applications for both the manual and automatic scanning techniques will increase. The initial interest and concentration on automatic scanning techniques has been overshadowed by the quality and diagnostic value of the manual grey-scale sector scans. The speed with which the
FIG. 11. Transverse scan of thyroid. The trachea appears black (T) and the lateral lobes of the thyroid lie on either side of it. There is a 2 cm cyst (A) in the left lateral lobe. The common carotid artery (arrowed) is just resolved.
FIG. 12. Transverse scan both testes. There is a small defect due to an occult tumour (arrowed) in the margin of the left testis.
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A clinical evaluation of grey-scale ultrasonography liver as revealed by grey-scale ultrasonography. The GLEES, J., TAYLOR, K. J. W., GAZET, J. C , and PECKHAM M. J., 1975. Superior accuracy of grey-scale ultrasonodiagnosis of necrotic tumour, cysts and abscesses graphy of liver and spleen in Hodgkin's disease and requires attention to features such as the number lymphomas compared with isotope scans. Clinical Radiology (in press). present, the shape of the lesion and its internal strucGROS, C , WALTER, J. P., and PARISOT, B., 1972. Echoture. Thus, although considerable experience is graphy in liver pathology. Journal de Radiologie d'elecrequired to make a confident diagnosis, the method trologie, 53, 1AQ-1AX. is potentially so accurate that time spent in training HILL, C. R., and CARPENTER, D. A., 1976. Ultrasonic Echo imaging of tissue: Instrumentation. British Journal of is worthwhile. Radiology 49, 238-243. The spleen is an organ which has proved difficult HOLM, H. H., 1971. Ultrasonic scanning in the diagnosis of space-occupying lesions of the upper abdomen. British to assess by plain radiography or isotope methods. Journal of Radiology, 44, 24—36. Our preliminary work would indicate already that HOLMES, J. H., 1966. Ultrasonic diagnosis of liver disease. In Diagnostic Ultrasound, eds. C. C. Grossman, J. H. ultrasound grey-scale techniques will be of great Holmes, C. Joyner and E. W. Purnell, pp. 249-265 value even in diffuse diseases. Very encouraging (Plenum Press, New York). results have been found in the genitourinary system 1972. Ultrasonic studies of the abdomen, p. 61 (Colorado; University of Colorado School of Medicine). although grey-scale techniques have less advantage HOWRY, D. H., 1965. A brief atlas of diagnostic ultrasonic over conventional scanners. However, the high resoradiologie results. Radiologie Clinics of North America, 3, 433-452. lution and intratumour details visualized indicate that better equipment yields better quality pictures KOSSOFF, G., 1972. Improved techniques in ultrasonic cross-sectional echography. Ultrasonics, 10, 221-229. even if the overall diagnostic accuracy is not mar1974. Display techniques in ultrasound pulse echo investigations: A review. Journal of Clinical Ultrasound, kedly improved. 2, 61-72. Of course conventional techniques have been KOSSOFF, G., and GARRETT, W. J., 1972. Ultrasonic film highly successful in the obstetrics field for many echography in gynecology and obstetrics. Obstetrics and Gynecology, 40, 299-305. years. The grey-scale technique makes placental KOSSOFF, G., GARRETT, W. J., and RADAVANOVICH, G., 1974. identification considerably easier even in less exUltrasonic atlas of normal brain of infant. Ultrasound in Medicine and Biology, 1, 259-266. perienced hands. In this field the quality of the scans obtained by Kossoff and his team, using grey LEYTON, B., HALPERN, S., LEOPOLD, G., and HAGEN, S., 1973. Correlation of ultrasound and colloid scintiscan scale coupled to an automatic scanner, would suggest studies of the normal and diseased liver. Journal of Nuclear Medicine, 14, 27-33. that future departments are likely to have a series of C. F., DAVIES, E. R., WELLS, P. N. T., Ross, specialized ultrasound scanners for specific organs. MCCARTHY, F. G. M., FOLLET, D. H., MUIR, K. M., and READ, In some applications, ultrasound techniques may A. E. A., 1970. A comparison of ultrasonic and isotopic scanning in the diagnosis of liver disease. British Journal replace current intrusive imaging techniques but in of Radiology, 43,100-109. general they offer extra information which comple- MELKI, G., 1973. Ultrasonic patterns of tumours of the ments other diagnostic techniques. liver. Journal of Clinical Ultrasound, 1, 306-314. MISKIN, M., and BAIN, J., 1974. B mode ultrasonic ex-
amination of the testis. Journal of Clinical Ultrasound, 2, 307-311.
ACKNOWLEDGMENT
We wish to acknowledge financial support by the Department of Health and Social Security for the development of the instrumentation used in this study.
MOUNTFORD, R. A., and WELLS, P. N. T., 1972a. Ultrasonic
liver scanning: the quantitative analysis of the normal A scan. Physics in Medicine and Biology, 17, 14—25. 1972b. Ultrasonic liver scanning: The A scan in the normal and in cirrhotics. Physics in Medicine and biology 17,261-269.
REFERENCES BARNETT, E., and MORLEY, P., 1971. Ultrasound in the
investigation of space-occupying lesion of the urinary OSTRUM, B. J., GOLDBERG, B. B., and ISARD, H. J., 1967. A mode ultrasound differentiation of soft tissue masses. tract. British Journal of Radiology, 44, 733-742. Radiology, 88, 745-749. 1972. Diagnostic ultrasound in renal disease. British SMITH, I., TAYLOR, K. J. W., MCCREADY, V. R., and Medical Bulletin, 28,196-199. POWLES, T., 1976. Comparison of grey-scale ultrasound 1974. Urinary tract. In Abdominal Echography-Ultrasound in the Diagnosis of Abdominal Conditions, pp. 53- with other methods for detection of liver metastases from carcinoma of breast (Submitted for publication). 69 (Butterworths, London). BUTLER, T. J., and MCCARTHY, C. F., 1969. Pyogenic liver TAYLOR, K. J. W., 1974. Letter. Journal of Clinical Ultrasound, 2, 7A-16. abscess. Gut, 10, 389-399. TAYLOR, K. J. W., and CARPENTER, D. A., 1974a. Com-
CROCKER, E. F.MCLAUGHLIN, A. F., KOSSOFF, G., and
parison of radioisotope and ultrasound examination in the investigation of hepatobiliary disease. In Ultrasound in Medicine, Vol. 1. Ed. D. White, pp. 159-167 (Plenum Press, New York). 1974b. Grey-scale ultrasonography in the investigation of obstructive jaundice. Lancet, 11, 586-7.
JELLINS, J., 1974. The grey-scale echographic appearances of thyroid malignancy. Journal of Clinical Ultrasound, 2,305-306. DONALD, I., MCVICAR, J., and BROWN, T. G., 1958.
Investigation of abdominal masses by pulsed ultrasound. Lancet, 1,1188-1194. FIELDS, S., and DUNN, F., 1973. Correlation of echographic
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visualizability of tissue with biological composition and physiological state. Journal Acoustic Society of America, 54,809-812. 251
V. R., 1974. Ultrasound and scintigraphy in the differential diagnosis of obstructive jaundice. Journal of Clinical Ultrasound, 2, 105-116.
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TAYLOR, K. J. W., and HILL, C. R., 1975. Scanning tech-
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value of ultrasonic diagnosis of liver abscess; a report of 218 cases. Chinese Medical Journal, 83, 133-140.
TAYLOR, K. J. W., and MCCREADY, V. R., 1975. Compari-
son of radioisotope and ultrasound scans of the thyroid.
Book review Brain Scintigraphy. By Lourens Penning and Dov Front, pp. xi+384, 1975 (Amsterdam, Excerpta Medica), Dfl. 148.00. There is one strange thing about this excellent book. Apart from their names, it is difficult to discover any information about the authors. Both will be known to all of us who are interested in cerebral scanning from their published works. Professor Penning is a neuroradiologist at the University Hospital of Groningen, and Professor Front is a neurologist working in the Nuclear Medicine Department of the University of Haifa. That both authors are very clinically orientated is one of the chief delights of this book. Indeed, the title is misleading, for this is far more than a text-book of brain scintigraphy. The book is divided into sections, and each section is sub-divided into the written text and the illustrations. This subdivision can be disturbing to one's concentration, requiring a search some 10 to 20 pages farther on for the correct illustration. Even with this arrangement there is a considerable amount of empty space between the illustrations which could have been used to increase the size of the robot pictures which are rather small for those not used to this technique. However, these are minor criticisms, and considering the profusion of pictures, the layout and format may have been inevitable. The quality of the pictures is superb, and a nice mixture of other neuroradiological techniques is included. The first section of the book deals with the normal scintigram, technique and normal anatomical details. The technique adopted is exhaustive, and one doubts if it could be practised in many departments in the United Kingdom. Rapid sequential pictures up to three per second are taken
by Robot 35 mm camera and followed by Polaroid film every 20 seconds, and at increasing intervals up to 30 minutes. Static scans are taken at one hour and may be repeated at three hours. This data may be increased in certain cases by an intra-arterial injection of isotope. Obviously, such a technique requires at least one gamma-camera dedicated totally to neuroradiology. There is, however, no doubt that this technique yields a lot of information in the author's hands. The second section deals with the abnormal scintigram. It contains a whole mine of information about cerebral tumours, infection, trauma, vascular lesions and a lot of other conditions—clearly presented and with excellent illustrations. The value of dynamic and sequential studies in the differential diagnosis of tumour histology is well discussed. The third section deals with CSF flow studied by cisternography—the problems of normal pressure hydrocephalus, of CSF leaks and various cystic conditions are all dealt with and the authors' considerable experience in this still developing area is again illustrated well and supported by line-drawings. The book, as a whole, gives a comprehensive and detailed account of cerebral scintigraphy including isotope arteriography, sequential and late static studies. There is an extensive list of references. It is well produced and a credit to the publishers—it even remains open at any chosen page. The price is high—approximately £30. Nevertheless, even if this sum is beyond the pocket of some individuals, this book is a must for every department of neuroradiology and of nuclear medicine.
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