Ultrasound Barbara
6. Gosink,
and the Gallbladder M.D.,
U
LTRASOUND examination is a relatively new approach to the diagnosis of gallbladder disease. Using gray scale ultrasound, the gallbladder can be satisfactorily outlined in approximately 95% of normal fasting patients.lb4+j In our hospitals. an abdominal ultrasound examination with specific attention to the gallbladder is routinely requested in patients who have had poor or nonvisualization of the gallbladder on a single oral cholecystogram. This is being done to compare the two techniques for accuracy in identifying cholelithiasis. Results of this study have been presented in another report.4 In clinical practice, indications for ultrasonic examination of the gallbladder include poor or nonvisualization of the gallbladder after two oral cholecystograms, jaundice, right upper quadrant pain, right upper quadrant mass, and fatty food intolerance or other symptoms suggestive of gallbladder disease. The procedure is safe, simple, and noninvasive. There are no known medical contraindications. However, the examination cannot be satisfactorily performed in the presence of gastrointestinal barium, excessive intestinal gas (as in patients with nonobstructive intestinal distension or intestinal obstruction), or large abdominal dressings that interfere with satisfactory placement of the transducer. Both barium and excessive gas cause reflection and scattering of the ultrasound beam,’ so that little intraabdominal detail can be defined. However, the liver can often be used as an “ultrasonic window” for visualizing the gallbladder even in the presence of excessive intestinal gas. In these patients, the transducer is positioned over the liver and aimed toward the gallbladder, thus delineating the organ without interference. Visualization of other pertinent organs, such as the pancreas, may Barbara 9. Gosink, M.D.: Assistant Professor of Radiology in Residence, Veterans Administration Hospital, San Diego, Calif George R. Leopold, M.D.: Associate Professor of Radiology, University Hospital of San Diego County, San Diego, Calif. Reprint requests should be addressed to Barbara B. Gosink, M.D., Veterans Administration Hospital, 3350 La Jolla Village Drive, San Diego, Calif: 92161. 0 1976 by Grune &Stratton, Inc.
Seminarsin
Roentgenology,
Vol.
Xl,
No.
3 (July),
1976
and
George
R. Leopold,
M.D.
still be impeded by the overlying gas- or bariumfilled intestine. When excessive gas is a problem in an otherwise normal patient, a trial of simethicone 40 mg q.i.d. for 3 days7 and careful attention to diet may be helpful in relieving the gas. EXAMINATION
TECHNIQUE
The patient should be placed on a low fat meal the evening before and take no food or liquids for approximately 12 hr preceding the examination. ‘This preparation usually ensures optimal distension of the gallbladder. Before examining the gallbladder region, an initial series of survey abdominal scans is performed with the patient in the supine position. These scans should include both transverse and longitudinal projections and are designed to explore the possibility of a related or unrelated lesion involving other organs. Particular attention is paid to the pancreatic region and to the hepatic parenchyma. The scans are performed during deep inspiration because this causes dilatation of the venous structures in the abdomen and the liver. The pancreas can then be identified on the transverse scan lying immediately anterior to the splenic vein. Similarly, dilatation of both tire hepatic veins and the portal venous system, along with lack of respiratory motion. improves visualization of these intrahepatic structures. An additional advantage of the inspiratory scan lies in the inferior displacement of the liver, permitting better delineation of its dome on the longitudinal view. Initial visualization of the gallbladder is best accomplished in the longitudinal projection during suspended inspiration. Since the fundus of the gallbladder lies just beneath the anterior abdominal wall in many patients, care must be used to avoid deforming the surface contour by excessrve transducer pressure. In some individuals, oblique views along the right costal margin produce a more satisfactory picture of the entire length of the gallbladder. A film from the oral cholecystogram may be used to help orient the scan in the appropriate longitudinal plane of t?hegallbladder. The longitudinal scans are done at half-centimeter intervals. proceeding from the medial to the lateral side of the organ. Transverse scans are then done from the tip 185
GOSINK
AND
LEOPOLD
Fig. 1. Normal transverse scan of the abdomen approximately 8 cm cephaled to the umbilicus (U + 8). In this and all subsequent transversescans, the right side of the patient will be on the right side of the illustration. Gallbladder (G), liver (L), right kidney (K), inferior vena cava (VI. Note the multiple fine echoes in the liver clearly distinguishing it from the sonolucent gallbladder. The gallbladder lies anterior and slightly medial to the right kidney in this patient.
of the fundus through the neck of the gallbladder, also at half-centimeter intervals. If the gallbladder cannot be seen on multiple attempts in several different positions the study is discontinued and repeated on another date. In most normal patients, the repeat examination will adequately delineate the organ. If the organ cannot be seen on repeat ultrasound examination, no diagnostic conclusions can be drawn, although cholelithiasis cannot be ruled out.4 If a real-time scanner is available, the gallbladder may be rapidly localized and its axis determined with this unit. This is particularly valuable in patients who are unable to suspend respiration
Fig. 2. Normal longitudinal scan of the abdomen approximately 8 cm to the right of midline (R8). This and all subsequent longitudinal scans are oriented so that the patient’s feet lie to the right of the picture. Gallbladder (G), liver (L), kidney (K). The gallbladder lies obliquely in the AP plane with its fundus just beneath the skin. The sonolucent structures seen within the liver are probably venous radicles. If accurate identification is desired, an attempt should be made to trace these radicles back to their origin using multiple scans at 0.5~cm intervals.
for satisfactory scans chine. Some real-time portable examination too ill to be brought to
on the conventional mascanners are also useful for at the bedside in patients the ultrasound department.
NORMAL APPEARANCE OF THE GALLBLADDER AND BILIARY TREE
On transverse sections, the normal gallbladder appears as a rounded-to-oval echo-free structure lying along the medial border of the liver just anterior to the right kidney (Fig. 1). In many individuals the gallbladder lies obliquely acrossboth the anteroposterior and lateral planes,with its fundus
ULTRASOUND
Fig. 3. Normal hepatic veins. Longitudinal scan at approximately R8. Hepatic veins (arrows) are seen traversing the liver substance (L) to enter the inferior vena cava (VI. This study was made in deep inspiration to distend the venous structures.
lateral and anterior to its neck. This obliquity is readily appreciated in the longitudinal projection (Fig. 2). In most people, the gallbladder measures less than 8 cm in length. However, normal gallbladders have been known to measure up to 13 cm in length. The gallbladder may appear somewhat dilated in normal fasting individuals and also in many patients with nonobstructive disease, such as pancreatitis and diabetes. It may also be dilated in the vagotomized patient.8 If in doubt as to the obstructive or nonobstructive nature of a dilated gallbladder, a fatty meal should be administered. When scanned approximately 30 min after the
Fig. 4. Normal portal vein. Transverse scan at approximately U + 11. Aorta (A), inferior vena cava WI, portal vein (PI, right kidney (K), liver (L). The portal vein is seen entering the liver substance. Careful scanning at 0.5-cm intervals may reveal its division into smaller branches. This scan was made in suspended respiration for adequate venous distension.
187
fatty meal, most normal gallbladders will show a decrease in size, helping to rule out obstructive disease. If there is no change in size between the two examinations, obstructive disease should be considered, although a small percentage of nonobstrutted gallbladders may also fail to contract. The intrahepatic biliary tree is not well delineated in most normal individuals. In both transverse and longitudinal scans, occasional small linear sonolucent structures may be seen within the hepatic parenchyma, representing either biliary ducts or venous structures; they usually cannot be differentiated from each other in the normal patient. Sometimes, on the longitudinal view, the hepatic veins may be traced to their entrance into the inferior vena cava (Fig. 3). Similarly, on the transverse view, portal vein radicles can occasionally be traced back to the portal vein as it enters the liver (Fig. 4). Although the normal common bile duct is not usually identified, sometimes it may be seen as a small circular lucent area slightly anterolateral to the portal vein. The hepatic artery also lies in this location, however. and cannot be distinguished from the normal common duct. In addition to variations in size, normal gallbladders may also vary in shape. Occasionally, the tip of the gallbladder may be seen to be folded on itself, the typical Phrygian cap appearance. Sometimes a portion of the gallbladder may show a concave impression from an adjacent bowel loop. In some patients, the fundus is seen well caudal to the liver substance, whereas in others the gallbladder is transversely oriented and appears to be completely surrounded by liver (Fig. 5).
GOSINK
186
AND
LEOPOLD
Fig. 6. Gallstones. Longitudinal scan at approximately R6. Two gallstones (arrow) lie in the most dependent tion of the gallbladder. The beam penetrates poorly yond the stones (acoustic shadowing).
Fig. rounded mately
5.
Normal gallbladder by liver substance. U + 10. Gallbladder
GALLBLADDER
almost completely surTransverse scan at approxi(G),liver (L),rightkidney (K).
DISEASE
Stones within the gallbladder can usually be identified by diagnosticultrasound. The stonesappear as strong echoes,lying in the most dependent part of the organ (Fig. 6). The sound beamusually doesnot penetrate beyond the stonesdue to their high echo-reflecting capability, thus producing a relatively echo-free “acoustic shadow” behind the stones (Fig. 7). When gallstones are identified, their presencecan be confirmed by a repeat scan of the patient either in the erect or left lateral de-
porbe-
cubitus position. This will demonstrate gravitational changein position of the stones.Edema of the gallbladder wall can occasionally be identified. Gallbladder distension is also readily identified by the use of ultrasound. The most distendedgallbladders, of course, are seenin patients with longstanding obstruction, such as that secondary to pancreatic or ampullary carcinoma. With obstruction of the biliary tree, the markedly distended intrahepatic radicles are readily identified on longitudinal scansof the liver during suspendedrespiration.2’g On both transverse and longitudinal scans, the distended common duct can also be seenfrequently. Careful attention is then given to identifying the pancreasand evaluating it for en-
Fig. 7. Acoustic shadow from gallstones. Transverse scan at approximately U + 6. In this patient with cholelithiasis (arrow), the acoustic shadow (9 is very prominent. Note that the medial portion of the right kidney (K) is not delineated due to the inability of the beam to penetrate beyond the gallstones.
189
ULTRASOUND
largement, particularly in the region of the pancreatic head. In some patients with an obviously distended gallbladder and normal biliary tree, we have been able to identify a stone lying in the cystic duct. Multiple stones within dilated intrahepatic ducts have also been identified by this technique. Frequently, very thick bile (“sludge”) can be seento layer posteriorly in the supinepatient with a chronically distended gallbladder.This thick bile produces no acoustic shadow, helping to differentiate it from multiple tiny stones.On changingthe patient’s position, the sludgewill slowly (ie, over about 5-10 min) slide into the most dependent portion of the gallbladder.
OVERALL
VALUE
Ultrasound examination of the gallbladder and adjacent pertinent structures is a rapid (15-45 minj, simple, and noninvasive meansof examining this organ. The procedure is safe, and is readily tolerated, even by very ill patients. Cholelithiasis, edema of the gallbladder wall, and tumor of the gallbladder can be demonstrated. One can readily distinguish obstructive from nonobstructive causes of jaundice and can often delineate the exact type and nature of the obstruction. Associatedpancreatic diseasecan be identified frequently. The procedure is relatively inexpensive and can be readily adapted for use in an office or small community hospital, aswell asin larger university centers.
REFERENCES I. Doust BD, Maklad NF: Ultrasonic B-mode examination of the gallbladder. Radiology 110:643-647, 1974 2. Gosink BB, Leopold GR: Abdominal echography. Semin Roentgen01 10:299-304, 1975 3. Hublitz UP, Kahn PC, Sell LA: Cholecystosonography: An approach to the nonvisualized gallbladder. Radiology 103:645-649, 1972 4. Leopold GR, Amberg JR, Gosink BB, et al: Gray scale ultrasonic cholecystography: A comparison with conventional radiographic techniques. Presented at Radiologic Society of North America Scientific Assembly, Chicago, 1975. 5. Leopold GR, Asher WM: Deleterious effects of gastrointestinal contrast material on abdominal echography. Radiology 98:637-640, 1971
6. Leopold GR, diagnosis of biliary 1052,1973
Sokoloff disease.
J: Ultrasonic scanning in the Surg Clin North Am 53: 1043-
7. Pepper HW, Keene J: Use of simethicone in abdominal echotomography. Presented at the American Institute of Ultrasound in Medicine Annual Meeting, WinstonSalem, NC, 1975 8. Sokoloff J, Gosink BB, Leopold GR, et al: Pitfalls in the echographic evaluation of pancreatic disease. J Clin Ultrasound 2:321-326, 1974 9. Taylor KJ, Carpenter DA, McCready VR: Ultrasound and scintigraphy in the differential diagnosis of obstructive jaundice. J Clin Ultrasound 2: 105-l 16, 1974
6. Gosink,
and the Gallbladder M.D.,
U
LTRASOUND examination is a relatively new approach to the diagnosis of gallbladder disease. Using gray scale ultrasound, the gallbladder can be satisfactorily outlined in approximately 95% of normal fasting patients.lb4+j In our hospitals. an abdominal ultrasound examination with specific attention to the gallbladder is routinely requested in patients who have had poor or nonvisualization of the gallbladder on a single oral cholecystogram. This is being done to compare the two techniques for accuracy in identifying cholelithiasis. Results of this study have been presented in another report.4 In clinical practice, indications for ultrasonic examination of the gallbladder include poor or nonvisualization of the gallbladder after two oral cholecystograms, jaundice, right upper quadrant pain, right upper quadrant mass, and fatty food intolerance or other symptoms suggestive of gallbladder disease. The procedure is safe, simple, and noninvasive. There are no known medical contraindications. However, the examination cannot be satisfactorily performed in the presence of gastrointestinal barium, excessive intestinal gas (as in patients with nonobstructive intestinal distension or intestinal obstruction), or large abdominal dressings that interfere with satisfactory placement of the transducer. Both barium and excessive gas cause reflection and scattering of the ultrasound beam,’ so that little intraabdominal detail can be defined. However, the liver can often be used as an “ultrasonic window” for visualizing the gallbladder even in the presence of excessive intestinal gas. In these patients, the transducer is positioned over the liver and aimed toward the gallbladder, thus delineating the organ without interference. Visualization of other pertinent organs, such as the pancreas, may Barbara 9. Gosink, M.D.: Assistant Professor of Radiology in Residence, Veterans Administration Hospital, San Diego, Calif George R. Leopold, M.D.: Associate Professor of Radiology, University Hospital of San Diego County, San Diego, Calif. Reprint requests should be addressed to Barbara B. Gosink, M.D., Veterans Administration Hospital, 3350 La Jolla Village Drive, San Diego, Calif: 92161. 0 1976 by Grune &Stratton, Inc.
Seminarsin
Roentgenology,
Vol.
Xl,
No.
3 (July),
1976
and
George
R. Leopold,
M.D.
still be impeded by the overlying gas- or bariumfilled intestine. When excessive gas is a problem in an otherwise normal patient, a trial of simethicone 40 mg q.i.d. for 3 days7 and careful attention to diet may be helpful in relieving the gas. EXAMINATION
TECHNIQUE
The patient should be placed on a low fat meal the evening before and take no food or liquids for approximately 12 hr preceding the examination. ‘This preparation usually ensures optimal distension of the gallbladder. Before examining the gallbladder region, an initial series of survey abdominal scans is performed with the patient in the supine position. These scans should include both transverse and longitudinal projections and are designed to explore the possibility of a related or unrelated lesion involving other organs. Particular attention is paid to the pancreatic region and to the hepatic parenchyma. The scans are performed during deep inspiration because this causes dilatation of the venous structures in the abdomen and the liver. The pancreas can then be identified on the transverse scan lying immediately anterior to the splenic vein. Similarly, dilatation of both tire hepatic veins and the portal venous system, along with lack of respiratory motion. improves visualization of these intrahepatic structures. An additional advantage of the inspiratory scan lies in the inferior displacement of the liver, permitting better delineation of its dome on the longitudinal view. Initial visualization of the gallbladder is best accomplished in the longitudinal projection during suspended inspiration. Since the fundus of the gallbladder lies just beneath the anterior abdominal wall in many patients, care must be used to avoid deforming the surface contour by excessrve transducer pressure. In some individuals, oblique views along the right costal margin produce a more satisfactory picture of the entire length of the gallbladder. A film from the oral cholecystogram may be used to help orient the scan in the appropriate longitudinal plane of t?hegallbladder. The longitudinal scans are done at half-centimeter intervals. proceeding from the medial to the lateral side of the organ. Transverse scans are then done from the tip 185
GOSINK
AND
LEOPOLD
Fig. 1. Normal transverse scan of the abdomen approximately 8 cm cephaled to the umbilicus (U + 8). In this and all subsequent transversescans, the right side of the patient will be on the right side of the illustration. Gallbladder (G), liver (L), right kidney (K), inferior vena cava (VI. Note the multiple fine echoes in the liver clearly distinguishing it from the sonolucent gallbladder. The gallbladder lies anterior and slightly medial to the right kidney in this patient.
of the fundus through the neck of the gallbladder, also at half-centimeter intervals. If the gallbladder cannot be seen on multiple attempts in several different positions the study is discontinued and repeated on another date. In most normal patients, the repeat examination will adequately delineate the organ. If the organ cannot be seen on repeat ultrasound examination, no diagnostic conclusions can be drawn, although cholelithiasis cannot be ruled out.4 If a real-time scanner is available, the gallbladder may be rapidly localized and its axis determined with this unit. This is particularly valuable in patients who are unable to suspend respiration
Fig. 2. Normal longitudinal scan of the abdomen approximately 8 cm to the right of midline (R8). This and all subsequent longitudinal scans are oriented so that the patient’s feet lie to the right of the picture. Gallbladder (G), liver (L), kidney (K). The gallbladder lies obliquely in the AP plane with its fundus just beneath the skin. The sonolucent structures seen within the liver are probably venous radicles. If accurate identification is desired, an attempt should be made to trace these radicles back to their origin using multiple scans at 0.5~cm intervals.
for satisfactory scans chine. Some real-time portable examination too ill to be brought to
on the conventional mascanners are also useful for at the bedside in patients the ultrasound department.
NORMAL APPEARANCE OF THE GALLBLADDER AND BILIARY TREE
On transverse sections, the normal gallbladder appears as a rounded-to-oval echo-free structure lying along the medial border of the liver just anterior to the right kidney (Fig. 1). In many individuals the gallbladder lies obliquely acrossboth the anteroposterior and lateral planes,with its fundus
ULTRASOUND
Fig. 3. Normal hepatic veins. Longitudinal scan at approximately R8. Hepatic veins (arrows) are seen traversing the liver substance (L) to enter the inferior vena cava (VI. This study was made in deep inspiration to distend the venous structures.
lateral and anterior to its neck. This obliquity is readily appreciated in the longitudinal projection (Fig. 2). In most people, the gallbladder measures less than 8 cm in length. However, normal gallbladders have been known to measure up to 13 cm in length. The gallbladder may appear somewhat dilated in normal fasting individuals and also in many patients with nonobstructive disease, such as pancreatitis and diabetes. It may also be dilated in the vagotomized patient.8 If in doubt as to the obstructive or nonobstructive nature of a dilated gallbladder, a fatty meal should be administered. When scanned approximately 30 min after the
Fig. 4. Normal portal vein. Transverse scan at approximately U + 11. Aorta (A), inferior vena cava WI, portal vein (PI, right kidney (K), liver (L). The portal vein is seen entering the liver substance. Careful scanning at 0.5-cm intervals may reveal its division into smaller branches. This scan was made in suspended respiration for adequate venous distension.
187
fatty meal, most normal gallbladders will show a decrease in size, helping to rule out obstructive disease. If there is no change in size between the two examinations, obstructive disease should be considered, although a small percentage of nonobstrutted gallbladders may also fail to contract. The intrahepatic biliary tree is not well delineated in most normal individuals. In both transverse and longitudinal scans, occasional small linear sonolucent structures may be seen within the hepatic parenchyma, representing either biliary ducts or venous structures; they usually cannot be differentiated from each other in the normal patient. Sometimes, on the longitudinal view, the hepatic veins may be traced to their entrance into the inferior vena cava (Fig. 3). Similarly, on the transverse view, portal vein radicles can occasionally be traced back to the portal vein as it enters the liver (Fig. 4). Although the normal common bile duct is not usually identified, sometimes it may be seen as a small circular lucent area slightly anterolateral to the portal vein. The hepatic artery also lies in this location, however. and cannot be distinguished from the normal common duct. In addition to variations in size, normal gallbladders may also vary in shape. Occasionally, the tip of the gallbladder may be seen to be folded on itself, the typical Phrygian cap appearance. Sometimes a portion of the gallbladder may show a concave impression from an adjacent bowel loop. In some patients, the fundus is seen well caudal to the liver substance, whereas in others the gallbladder is transversely oriented and appears to be completely surrounded by liver (Fig. 5).
GOSINK
186
AND
LEOPOLD
Fig. 6. Gallstones. Longitudinal scan at approximately R6. Two gallstones (arrow) lie in the most dependent tion of the gallbladder. The beam penetrates poorly yond the stones (acoustic shadowing).
Fig. rounded mately
5.
Normal gallbladder by liver substance. U + 10. Gallbladder
GALLBLADDER
almost completely surTransverse scan at approxi(G),liver (L),rightkidney (K).
DISEASE
Stones within the gallbladder can usually be identified by diagnosticultrasound. The stonesappear as strong echoes,lying in the most dependent part of the organ (Fig. 6). The sound beamusually doesnot penetrate beyond the stonesdue to their high echo-reflecting capability, thus producing a relatively echo-free “acoustic shadow” behind the stones (Fig. 7). When gallstones are identified, their presencecan be confirmed by a repeat scan of the patient either in the erect or left lateral de-
porbe-
cubitus position. This will demonstrate gravitational changein position of the stones.Edema of the gallbladder wall can occasionally be identified. Gallbladder distension is also readily identified by the use of ultrasound. The most distendedgallbladders, of course, are seenin patients with longstanding obstruction, such as that secondary to pancreatic or ampullary carcinoma. With obstruction of the biliary tree, the markedly distended intrahepatic radicles are readily identified on longitudinal scansof the liver during suspendedrespiration.2’g On both transverse and longitudinal scans, the distended common duct can also be seenfrequently. Careful attention is then given to identifying the pancreasand evaluating it for en-
Fig. 7. Acoustic shadow from gallstones. Transverse scan at approximately U + 6. In this patient with cholelithiasis (arrow), the acoustic shadow (9 is very prominent. Note that the medial portion of the right kidney (K) is not delineated due to the inability of the beam to penetrate beyond the gallstones.
189
ULTRASOUND
largement, particularly in the region of the pancreatic head. In some patients with an obviously distended gallbladder and normal biliary tree, we have been able to identify a stone lying in the cystic duct. Multiple stones within dilated intrahepatic ducts have also been identified by this technique. Frequently, very thick bile (“sludge”) can be seento layer posteriorly in the supinepatient with a chronically distended gallbladder.This thick bile produces no acoustic shadow, helping to differentiate it from multiple tiny stones.On changingthe patient’s position, the sludgewill slowly (ie, over about 5-10 min) slide into the most dependent portion of the gallbladder.
OVERALL
VALUE
Ultrasound examination of the gallbladder and adjacent pertinent structures is a rapid (15-45 minj, simple, and noninvasive meansof examining this organ. The procedure is safe, and is readily tolerated, even by very ill patients. Cholelithiasis, edema of the gallbladder wall, and tumor of the gallbladder can be demonstrated. One can readily distinguish obstructive from nonobstructive causes of jaundice and can often delineate the exact type and nature of the obstruction. Associatedpancreatic diseasecan be identified frequently. The procedure is relatively inexpensive and can be readily adapted for use in an office or small community hospital, aswell asin larger university centers.
REFERENCES I. Doust BD, Maklad NF: Ultrasonic B-mode examination of the gallbladder. Radiology 110:643-647, 1974 2. Gosink BB, Leopold GR: Abdominal echography. Semin Roentgen01 10:299-304, 1975 3. Hublitz UP, Kahn PC, Sell LA: Cholecystosonography: An approach to the nonvisualized gallbladder. Radiology 103:645-649, 1972 4. Leopold GR, Amberg JR, Gosink BB, et al: Gray scale ultrasonic cholecystography: A comparison with conventional radiographic techniques. Presented at Radiologic Society of North America Scientific Assembly, Chicago, 1975. 5. Leopold GR, Asher WM: Deleterious effects of gastrointestinal contrast material on abdominal echography. Radiology 98:637-640, 1971
6. Leopold GR, diagnosis of biliary 1052,1973
Sokoloff disease.
J: Ultrasonic scanning in the Surg Clin North Am 53: 1043-
7. Pepper HW, Keene J: Use of simethicone in abdominal echotomography. Presented at the American Institute of Ultrasound in Medicine Annual Meeting, WinstonSalem, NC, 1975 8. Sokoloff J, Gosink BB, Leopold GR, et al: Pitfalls in the echographic evaluation of pancreatic disease. J Clin Ultrasound 2:321-326, 1974 9. Taylor KJ, Carpenter DA, McCready VR: Ultrasound and scintigraphy in the differential diagnosis of obstructive jaundice. J Clin Ultrasound 2: 105-l 16, 1974
