Correspondence indicate that the lumbosacral junction was visualized adequately in 79% of patients and if the coned view is performed in everyone, then 79% of patients will be unnecessarily exposed to additional radiation. The policy that we have adopted following the guidelines of the NRPB, is to centre 1 cm above the iliac crest for a full length lateral view and leave it to the discretion of the radiographer to determine whether or not this has resulted in a diagnostic film of the lumber spine in the lateral projection. It is our intention to publish the results of this approach when a sufficient number are available. Yours etc., G. LAMB S. DAVIES
Department of Radiology, Royal Liverpool University Hospital, Prescot Street, Liverpool, L7 8XP (Received 3J July 1991, accepted 4 September 1991)
Reference EISENBERG, R.L., ATKIN, J.R. & HEDGCOCK, M.W., 1979. Single,
well centred lateral view of the lumbosacral spine: is a coned view necessary? American Journal of Roentgenology, 133,
711-713. Authors' reply THE EDITOR—SIR,
May we thank Lamb and Davies for their comments. We apologise for omitting the centring point for the lateral lumbar spine view. We used the lower costal margin as the departmental standard. We certainly did not intend any implication that all patients require a coned lumbosacral junction (LSJ) view. Quite the reverse! In our study, using the grading system, we showed that it was possible to predict accurately those patients with occult pathology in this region when a LSJ view was unavailable. We concur with Lamb and Davies that, provided a radiologist or experienced radiographer assesses the lateral lumbar view at the time of examination, a coned view can be avoided in those with Grade 1 visualization (i.e. full visualization of the end plate of L5 and the superior end plate of SI), but should be performed in those with Grade 2 or Grade 3 visualization. Yours etc., M. E. LIPTON V. PELLEGRINI I. HARRIS
Royal Liverpool University Hospital, Prescot Street, Liverpool, L7 8XP
Ultrasonic detection of parathyroid adenomas THE EDITOR - SIR,
Murchison et al (1991) are to be congratulated on the high accuracy they report for the pre-operative localization of large parathyroid tumours in a small series, and their figures confirm the supremacy of ultrasound for pre-operative localization in primary hyperparathyroidism. With modern high-resolution ultrasound equipment, it is still impossible to demonstrate reliably normal parathyroid glands and it is difficult to detect small tumours, those located in unusual ectopic sites such as lateral to the carotid sheath and, as with frozensection histology, distinguish adenoma from hyperplasia. All the cases they describe had a "positive" ultrasound scan and apart from the one intrathyroidal parathyroid tumour, no ectopic glands or cases of hyperplasia are described. If their series was of all patients undergoing pre-operative attempts at ultrasound parathyroid localization during the study period, the inclusion of patients with a "negative" scan might result in their figures for sensitivity and specificity approximating to other published data. Yours, etc., M. N. H. LLOYD
Department of Radiology, Southampton General Hospital, Tremona Road, Southampton SO9 4XY (Received 23 August 1991, accepted 13 September 1991)
Reference MURCHISON, J., MCINTOSH, C , AITKEN, A. G. F., LOGIE, J. &
MUNRO, A., 1991. Ultrasonic detection of parathyroid adenomas. The British Journal of Radiology, 64, 679-682.
Authors' reply THE EDITOR—SIR
We thank M. Lloyd for his comments. In our study all patients presenting with biochemical evidence of primary hyperparathyroidism and raised parathormone levels did in fact undergo pre-operative localization with ultrasound. All scans were positive. If there had been any negative scans we would have included them in our figures. We do acknowledge that had there been any ectopic parathyroid adenomas in our series then this might have resulted in a lower sensitivity. Yours, etc,
(Received 21 August 1991, accepted 4 September 1991)
Reference LIPTON, M. E., PELLEGRINI, V. & HARRIS, I., 1991. Is the coned
lateral lumbosacral junction radiograph necessary for radiological diagnosis? British Journal of Radiology, 64, 420-421.
Vol. 65, No. 769
A. G. F. AITKEN
Department of Radiodiagnosis, Raigmore Hospital, Inverness, IN2 3UJ (Received 6 September 1991, accepted 13 September 1991)
95
Department of Radiology, Royal Liverpool University Hospital, Prescot Street, Liverpool, L7 8XP (Received 3J July 1991, accepted 4 September 1991)
Reference EISENBERG, R.L., ATKIN, J.R. & HEDGCOCK, M.W., 1979. Single,
well centred lateral view of the lumbosacral spine: is a coned view necessary? American Journal of Roentgenology, 133,
711-713. Authors' reply THE EDITOR—SIR,
May we thank Lamb and Davies for their comments. We apologise for omitting the centring point for the lateral lumbar spine view. We used the lower costal margin as the departmental standard. We certainly did not intend any implication that all patients require a coned lumbosacral junction (LSJ) view. Quite the reverse! In our study, using the grading system, we showed that it was possible to predict accurately those patients with occult pathology in this region when a LSJ view was unavailable. We concur with Lamb and Davies that, provided a radiologist or experienced radiographer assesses the lateral lumbar view at the time of examination, a coned view can be avoided in those with Grade 1 visualization (i.e. full visualization of the end plate of L5 and the superior end plate of SI), but should be performed in those with Grade 2 or Grade 3 visualization. Yours etc., M. E. LIPTON V. PELLEGRINI I. HARRIS
Royal Liverpool University Hospital, Prescot Street, Liverpool, L7 8XP
Ultrasonic detection of parathyroid adenomas THE EDITOR - SIR,
Murchison et al (1991) are to be congratulated on the high accuracy they report for the pre-operative localization of large parathyroid tumours in a small series, and their figures confirm the supremacy of ultrasound for pre-operative localization in primary hyperparathyroidism. With modern high-resolution ultrasound equipment, it is still impossible to demonstrate reliably normal parathyroid glands and it is difficult to detect small tumours, those located in unusual ectopic sites such as lateral to the carotid sheath and, as with frozensection histology, distinguish adenoma from hyperplasia. All the cases they describe had a "positive" ultrasound scan and apart from the one intrathyroidal parathyroid tumour, no ectopic glands or cases of hyperplasia are described. If their series was of all patients undergoing pre-operative attempts at ultrasound parathyroid localization during the study period, the inclusion of patients with a "negative" scan might result in their figures for sensitivity and specificity approximating to other published data. Yours, etc., M. N. H. LLOYD
Department of Radiology, Southampton General Hospital, Tremona Road, Southampton SO9 4XY (Received 23 August 1991, accepted 13 September 1991)
Reference MURCHISON, J., MCINTOSH, C , AITKEN, A. G. F., LOGIE, J. &
MUNRO, A., 1991. Ultrasonic detection of parathyroid adenomas. The British Journal of Radiology, 64, 679-682.
Authors' reply THE EDITOR—SIR
We thank M. Lloyd for his comments. In our study all patients presenting with biochemical evidence of primary hyperparathyroidism and raised parathormone levels did in fact undergo pre-operative localization with ultrasound. All scans were positive. If there had been any negative scans we would have included them in our figures. We do acknowledge that had there been any ectopic parathyroid adenomas in our series then this might have resulted in a lower sensitivity. Yours, etc,
(Received 21 August 1991, accepted 4 September 1991)
Reference LIPTON, M. E., PELLEGRINI, V. & HARRIS, I., 1991. Is the coned
lateral lumbosacral junction radiograph necessary for radiological diagnosis? British Journal of Radiology, 64, 420-421.
Vol. 65, No. 769
A. G. F. AITKEN
Department of Radiodiagnosis, Raigmore Hospital, Inverness, IN2 3UJ (Received 6 September 1991, accepted 13 September 1991)
95
