MR myelography using heavily T2-weighted fast spin-echo pulse sequences with fat presaturation.

A new method for generating myelogramlike images of the thecal sac by MR imaging is presented. The method is based on suppressing background signal by using heavily T2-weighted fast spin-echo pulse sequences and obliterating fat signal by presaturation. The resulting slices are then projected into a composite image using a standard maximum intensity projection (MIP) algorithm. The technique is implemented with commercially available hardware and software and yields reproducible high-quality images of the lumbar thecal sac, which show excellent definition of the thecal margins, nerve roots, and nerve root sheaths. This method could replace conventional lumbar myelography and postmyelographic CT studies.

Localization of parathyroid adenomas in patients who have undergone surgery. Part I. Noninvasive imaging methods.

The authors evaluated computed tomography (CT), ultrasound (US), technetium/thallium scintigraphy, and magnetic resonance (MR) imaging as localization procedures in 53 patients with proved parathyroid adenomas and previous unsuccessful parathyroid surgery. CT had the highest overall sensitivity (47%), followed by US (36%) and scintigraphy (27%). There is still too little data to assess MR imaging. Adenoma size affected the sensitivity of CT, scintigraphy, and MR imaging but not US. When all three studies were used, at least one study depicted a lesion in 78% of patients, but definitive localization (two positive studies) was achieved in only 31%.

Localization of parathyroid adenomas in patients who have undergone surgery. Part II. Invasive procedures.

The authors studied intraarterial digital subtraction angiography (DSA), conventional selective angiography, parathyroid venous sampling (PVS), and intraoperative ultrasound (US) as localization procedures for parathyroid adenomas in 53 patients with proved parathyroid adenomas and previous unsuccessful parathyroid surgery. PVS had the highest overall sensitivity as a single study (80%), followed by intraoperative US (78%), angiography (60%), and DSA (49%). Invasive procedures permitted successful localization of adenomas in 41 of 43 patients studied (95%). False-positive studies were uncommon. The optimum sequence of invasive localization procedures is determined by clinical factors and not by the sensitivity of individual tests. The authors recommend DSA be performed first, followed by angiography, PVS, and intraoperative US, in that order.

Selective venous sampling for gastrin to localize gastrinomas. A prospective assessment.

In 27 consecutive patients with Zollinger-Ellison syndrome, we prospectively evaluated the ability of selective venous sampling for gastrin to localize gastrinomas, then compared the results with those from imaging studies and with findings at surgery. All patients had a gastrin gradient, but in only 20 patients was it significant. Neither the magnitude of the gastrin gradient nor its presence or absence correlated with the frequency with which gastrinoma was found at surgery. A gastrinoma was found at surgery in 15 patients, of whom 12 had positive imaging studies, 11 had a significant gastrin gradient, 14 had both tests positive, and 1 had both tests negative. A gastrinoma was not found at surgery in 12 patients, of whom 8 had a significant gradient and none had a positive imaging study. Gastrin sampling has equal sensitivity with imaging studies in localizing gastrinoma, but imaging studies have higher positive and negative predictive values and higher specificity. Thus, selective venous sampling for gastrin is much less useful in localizing gastrinoma than has been suggested and should not be routinely done preoperatively in patients with Zollinger-Ellison syndrome.

Lymph node aspiration in the management of Hodgkin's disease.

Diagnosing recurrent Hodgkin's disease is an important oncologic problem. When relapse does not occur in peripheral nodal sites, then a major surgical exploration is often considered. Lymph node aspiration is proposed as a less invasive approach capable of establishing a diagnosis in some instances. In this retrospective study, 19 patients with Hodgkin's disease underwent 64 lymph node aspirations. Of these patients, 17 had suspected Hodgkin's disease with involvement at an inaccessible site. Two patients with a primary diagnosis of Hodgkin's disease underwent aspiration of a peripheral site. Of these 19 patients, five (26.3%) had a positive aspirate and only two (10.5%) had an unsatisfactory aspirate. No patient had a false-positive aspirate. Of 15 patients with a negative aspirate, five (33%) had a false-negative aspirate. In no case did a false-negative aspirate delay appropriate therapy. In those patients with a positive aspirate, surgical exploration was avoided. We conclude that lymph node aspiration cytology is useful as an initial step to document clinical relapse of Hodgkin's disease at a site that might require a major surgical procedure for diagnosis.

Parathymic parathyroid: CT, US, and angiographic findings.

Six patients with primary hyperparathyroidism caused by an undescended parathymic adenoma are described. All glands were anterior to the common carotid artery at the level of the hyoid bone. Blood supply was from the superior thyroid artery, and venous drainage was into the superior thyroid vein. Ultrasound (one of five) and computed tomography (two of six) were rarely positive, but glands can be detected with both modalities if the examination is carried high enough. Glands within the carotid sheath are generally lower in the neck and have a blood supply from the inferior thyroid artery with drainage into the vertebral veins.

Basilar venous plexus of the posterior fossa: a potential source of error in petrosal sinus sampling.

Sampling of serum from the inferior petrosal sinus can provide important information about the source of elevated adrenocorticotropic hormone (ACTH) levels. This often leads to improved results of pituitary surgery for Cushing disease. The authors describe a successful catheterization technique and illustrate the venous anatomy of the inferior petrosal sinuses and basilar plexus.

Localization of an occult insulinoma by intraoperative ultrasonography.

Intraoperative ultrasonography has not been used previously to locate an insulinoma that was not surgically palpable or that could not be seen by selective arteriography. In this report we described a patient with an insulinoma localized to the pancreatic head identified by transhepatic portal venous sampling but not by selective arteriography or palpation. At operation intraoperative ultrasonography demonstrated an 8 mm tumor in the pancreatic head and guided the successful enucleation.

Use of a microcomputer to store information on radiology cases.

A microcomputer program for storage of qualitative patient data has been applied to CT and special procedures case data. Different vocabularies have been established and utilised for these two case categories. Experience over two years involving more than 10,000 cases is discussed. Utility for statistical, research, and patient care purposes is demonstrated.

Removal of gastrinomas for control of Zollinger-Ellison syndrome.

There are two distinct problems in patients with Zollinger-Ellison Syndrome (ZES): peptic ulcer diathesis and malignant tumors. Antisecretory drugs have allowed us to control the ulcer symptoms and acid output in 45 patients with ZES. We report here the initial seven patients selected for surgical exploration with the goal of removing their gastrinomas. Prior to surgery, an extensive and rigorous protocol to localize the gastrinoma was carried out, including hypotonic duodenography, abdominal ultrasonography, selective arteriography, portal vein sampling for gastrin, and computerized tomography. With this protocol of radiographic localization, gastrinomas were found in two of the seven cases and the syndrome was "cured" in three of the seven patients. The results also demonstrate that preoperative localization is not a substitute for careful surgical exploration as tumors were found in two patients in whom localization failed.

Intraoperative urinary cyclic adenosine monophosphate as a guide to successful reoperative parathyroidectomy.

Sixty patients with persistent or recurrent primary hyperparathyroidism underwent reexploration during which urinary cyclic adenosine monophosphate (UcAMP) levels were determined at half-hour intervals by radioimmunoassay. Retrospective analysis of the data allowed us to develop UcAMP criteria for surgical success. Following removal of parathyroid tissue, if an individual UcAMP level dropped 50% from the median baseline level, or if elevated levels dropped to less than 4.0 nmol/dl glomerular filtrate, surgery was predicted to be successful. Eight unsuccessful procedures in seven patients produced no decline in UcAMP, and the intraoperative results accurately predicted surgical failure. Fifty-three patients underwent successful procedures and in every case UcAMP fell. Ninety-eight per cent of these successful procedures were predicted by our criteria. Levels of UcAMP fell 1.5 +/- 0.5 hours (means +/- SD) following abnormal parathyroidectomy. In 19 of 36 successful cases diagnosed before surgery as adenoma, the operative procedure was terminated before a significant drop in UcAMP. In 16 of 17 successful cases diagnosed before surgery as hyperplasia or uncertain histology, UcAMP fell during the operation. Intraoperative determination of UcAMP is helpful in reoperative parathyroid surgery. The criteria established allow intraoperative prediction of success with remarkable accuracy. Urinary cyclic AMP is especially helpful in reoperation for multigland disease; when enough pathologic tissue has been removed, the criteria will be met and the procedure may be terminated with confidence.

Localization of islet cell tumors by dynamic CT: comparison with plain CT, arteriography, sonography, and venous sampling.

Ten patients with suspected islet cell tumors (seven with possible gastrinomas, three with insulinomas) underwent diagnostic evaluation with dynamic CT scanning, routine CT scanning, angiography, and sonography. Venous sampling was also performed in selected instances. Nine sites of gastrinoma and three insulinomas were confirmed surgically in eight patients. Two patients had negative surgical explorations. Routine CT demonstrated five of the nine gastrinomas and one of two insulinomas. Angiography was positive in six of nine gastrinomas and all three insulinomas. Sonography showed only two of the nine gastrinomas and two of the three insulinomas. Dynamic CT scanning demonstrated three additional lesions (two gastrinomas, one insulinoma) not visible on routine CT scanning. Although most of these lesions were visible arteriographically, dynamic CT scans at the appropriate level localized the pathology in the transverse plane and greatly aided in surgical resection of these lesions. Dynamic CT scanning is a useful adjunct to routine angiographic and CT workup of patients with islet cell tumors.

Parathyroid aspiration directed by angiography: an alternative to venous sampling.

Not all parathyroid glands can be visualized by CT or ultrasound and, therefore, cannot be aspirated using these techniques. We report the localization of a parathyroid gland by arteriography and needle aspiration under fluoroscopic guidance. This technique can be used to confirm a diagnosis of hypervascular parathyroid tissue that cannot otherwise be confirmed.

Detection of mediastinal parathyroid glands by nonselective digital arteriography.

Six patients with failed previous operations and anterior mediastinal parathyroid glands were evaluated with selective angiography and nonselective arterial digital arteriography. Selective angiography depicted two of nine mediastinal glands; nonselective arterial digital arteriography depicted only one of nine mediastinal glands and missed a sizable (4.5 cm) gland demonstrated by routine arteriography. Nonselective arterial digital arteriography did not demonstrate any additional mediastinal glands. From this preliminary experience, it was concluded that nonselective arterial digital arteriography is not a sensitive method for detecting mediastinal glands.

Ultrasonic parathyroid localisation in previously operated patients.

Sixty-two patients with hyperparathyroidism and failed prior neck surgery were examined by ultrasound before reoperation to localise abnormally enlarged glands. If mediastinal lesions are excluded, a total of 57 glands greater than 5 mm in size were removed from 48 patients. Ultrasound demonstrated only 18 of these for a true positive rate of 32%. There were 39/57 (68%) false negatives. In addition, there were 16 false positives. In our experience, the detection rate of ultrasound for enlarged parathyroid glands in patients with failed surgery is significantly less than that reported in previously unoperated patients (73%), or in the limited number of reported cases of patients with previous operations (75%). Our high false negative rate is probably partially due to the large number of posteriorly located small glands which cannot be adequately visualised by ultrasound. Nevertheless, because of its non-invasive nature, low cost and ready availability, ultrasound should be utilised as an initial screening procedure in patients with failed previous surgery.

Petrosal sinus sampling for Cushing syndrome: anatomical and technical considerations. Work in progress.

ACTH-producing microadenomas of the pituitary gland drain unilaterally into the adjacent cavernous sinus; therefore, petrosal sinus sampling to distinguish pituitary from ectopic-ACTH syndromes must always be performed bilaterally. A negative finding from a unilateral petrosal sinus sample does not exclude the presence of a contralateral ACTH-producing microadenoma. Hemiresection of the pituitary gland based on results of bilateral sampling can be performed if the adenoma is too small to be recognized at surgery. Large pituitary adenomas produce elevated ACTH levels in the petrosal sinuses bilaterally. However, if plain radiographs or CT scans provide unequivocally positive findings in Cushing syndrome (less than 20%), inferior petrosal sinus sampling is not indicated.

Hyperfunctioning cystic parathyroid glands: CT and sonographic findings.

Four functioning cystic parathyroid glands were evaluated with computed tomography (CT) and sonography in four patients, only one of whom had prior surgery. Sonography demonstrated solid lesions of decreased echogenicity with fluid-filled cavities near the lower thyroid poles or in the posterosuperior mediastinum. On CT the cystic parts of the lesions were of low attenuation (1-44 H), often with a well defined wall that was better demonstrated after intravenous contrast administration. Fine-needle aspiration biopsy of two of the cystic parathyroids revealed elevated parathyroid hormone levels. These lesions probably represent degenerating adenomas rather than true parathyroid cysts. While the CT and sonographic findings are nonspecific, the diagnosis of a cystic parathyroid should be entertained when a fluid-filled lesion is encountered in the neck of a patient with or without hypercalcemia. The diagnosis may be confirmed by assay of parathyroid hormone from the fluid aspirate.