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At least 109 records · Page 6Linked to original sources

A new adrenal computer imaging technique using dual-radioisotopes.

Computer processed adrenal imaging using dual-radioisotopes, 6 beta-iodomethyl-19-nor-cholest-5(10)-en-3 beta-ol-131I and 99mTc-phytate was performed in 12 patients with primary aldosteronism and 4 with Cushing's syndrome due to adrenocortical tumor. Adreno-photoscanning and hepato-photoscanning were performed in the same position 2-4 days following intravenous administration of radiocholesterol. The scintigraphic information was stored on cassettes and scan subtraction and a digital-computer method for data smoothing were performed on an oscilloscope. The tumor site could be determined in all cases until day 4 by this computer processed image.

Adosterol↗

Preclinical Cushing's syndrome due to ACTH-independent bilateral macronodular adrenocortical hyperplasia with excessive secretion of 18-hydroxydeoxycorticosterone and corticosterone.

A 64-year-old woman developed hypertension and hypokalemia, due to ACTH-independent bilateral macronodular adrenocortical hyperplasia (AIMAH) with excessive secretion of 18-hydroxydeoxycorticosterone and corticosterone. Plasma cortisol did not show a diurnal rhythm, and was not suppressed by dexamethasone (8 mg). Plasma cortisol responded to ACTH and was increased by hypoglycemia without modifying ACTH levels. Radiological studies demonstrated that adrenal glands were enlarged with macronodules. Although the patient exhibited a low plasma renin activity and aldosterone levels, hypokalemia and hypertension were observed. Hormonal findings would support the hypothesis that the tumor of AIMAH originated from cells of the upper zona fasciculata.

18-Hydroxydesoxycorticosterone↗

Failure to visualize bilateral adrenal glands in a patient with primary aldosteronism.

Failure to visualize either adrenal gland by adrenal imaging was experienced in a patient with biochemical evidence of primary aldosteronism. Visualization of the adrenal glands was not possible after the administration of ACTH-Z (1 mg/day) for 3 days. The administration of ACTH and dexamethasone elicited an increase in blood pressure. Although the reason for this failure to visualize the adrenal glands by scanning and for the rise in blood pressure brought on by ACTH and dexamethasone remain unclear, we think that the case herein reported is a rare type of primary aldosteronism.

Adosterol↗

[Role of adrenocortical scintigraphy in the exploration of incidentally discovered tumors].

To determine the utility of adrenocortical scintigraphy with I131-6 beta-iodomethyl-19-nor-cholesterol (NP59) in incidentally discovered adrenal masses, we studied 12 patients with a unilateral adrenal mass and without other primary tumors or signs of pheochromocytoma or hyperfunctioning adenoma. Ten patients had an adenoma (size: 12 to 35 mm), the diagnosis was made by surgery or by no change in size on repeated CT scans. The NP59 scintigraphy showed an increased uptake on the side of the tumor in 8 cases with a decreased uptake of contra-lateral gland in 7 cases. Hormonal investigations of glucocorticoid function suggested supranormal or fluctuant cortisol secretion in 5 cases as assessed by moderately elevated urinary free cortisol or by incomplete dexamethasone suppression test. These abnormalities disappeared after surgery. Two patients had normal bilateral uptake of NP59, the sizes of the tumors were 12 and 20 mm. Two patients had an extra-adrenal tumor. The NP59 scintigraphy showed a moderately decreased uptake on the side of the hematoma of one patient and a compression of the normal adrenal by ganglioneuroma of the other patient. Our results and those of other authors suggest that positive NP59 scintigraphy could confirm the cortical nature of an incidentally discovered adrenal mass, probably an adenoma that must be followed up morphologically and functionally. No uptake by a tumor greater than 2 cm suggests a primary malignancy or extra-adrenal origin which must be diagnosed by invasive methods.

Adenoma↗

Adrenal scintigraphy of well-differentiated (functioning) adrenocortical carcinomas: potential surgical pitfalls.

Adrenal scintigraphy with 131I-6 beta-iodomethylnorcholesterol (NP-59) has been widely used to evaluate adrenal cortical tumors during the past 20 years. Unilateral visualization on the side of an adrenal tumor has been considered diagnostic of a benign adrenocortical adenoma in the patient with Cushing's syndrome. Bilateral nonvisualization of the adrenal glands in the presence of Cushing's syndrome is considered diagnostic of adrenocortical carcinoma (ACC). ACCs characteristically are unable to incorporate enough NP-59 to be visualized on NP-59 adrenal scintigraphy. Two patients with well-differentiated cortisol-secreting ACCs, in which the primary tumor or subsequent metastases demonstrated intense uptake (visualization) on NP-59 scans are reported here. As a result of these findings on NP-59 adrenal scintigraphy, the lesions were initially misinterpreted to represent benign disease. In each patient the operative approach selected, based on the interpretation of the NP-59 scan, was inappropriate for the management of the respective adrenal neoplasm or its metastasis. A review of the literature reveals 16 other cases of either ACC or their metastases that were visualized with adrenal scintigraphy. Ninety percent of these cases were associated with adrenocortical hormone hypersecretion. It is concluded that in the presence of Cushing's syndrome or another adrenocortical hormone excess state, unilateral visualization of an adrenal tumor on NP-59 scintigraphy cannot be interpreted to represent uniformly benign disease.

Adosterol↗

I-131 NP-59 adrenal cortical scintigraphy in suspected primary aldosteronism.

Dexamethasone suppression [Iodine-131] 6-Beta-Iodomethy1-19- Norcholesterol (I-131 NP-59) adrenal cortical scintigraphy was performed in 35 patients with suspected primary aldosteronsim, between May 1983 and June 1990. Based on clinical, biochemical, radiographic and pathologic data, the diagnostic accuracy of primary aldosteronism from I-131 NP-59 adrenal cortical scintigraphy was evaluated. The sensitivity, specificity, positive predictive accuracy and negative predictive accuracy was 78.9%, 100%, 100% and 80% respectively. We conclude that I-131 NP-59 adrenal cortical scintigraphy is an accurate and noninvasive technique for the diagnosis of suspected primary aldosteronism.

Adosterol↗

[Preoperative diagnostics in patients with adrenal tumors].

The aim of the study was analysis of preoperative diagnostics of patients who underwent laparoscopic adrenalectomy. In the preoperative diagnostics in 10 patients (22.2%) pheochromocytoma was found, in 8 (17.8%) Conn's syndrome, in 4 (8.9%) Cushing's syndrome and in 1 (2.2%) adrenal virilization. Full accordance between histopathological findings and preoperative diagnosis was achieved in 91% of cases. Four cases of discrepancy were: 1 false positive preoperative diagnosis of aldosteronoma, 1 false positive and 2 false negative diagnosis of pheochromocytoma.

Adosterol↗

Clinical significance of the solitary functioning adrenal gland.

To assess the compensatory functional and anatomic changes in the remaining adrenal cortex after unilateral adrenalectomy or in the unaffected adrenal in patients with unilateral adrenal destruction by neoplasm, 17 patients with a single, functioning adrenal gland and normal indices of adrenocortical function, nine after adrenalectomy and eight with a unilateral, destructive adrenal lesion were studied with 131I-6 beta-iodomethyl-19-norcholesterol (NP-59) scintigraphy and computed tomography. Adrenal masses with a mean (+/- s.d.) diameter of 2.8 +/- 1.0 cm; (range 1-4 cm; 95% confidence interval (Cl), 2.5-3.1 cm) were identified by computed tomography in seven of nine patients in the remaining adrenal cortex at variable times (6.1 +/- 5.9 y; range 0.5-19 y) after unilateral adrenalectomy. Mean (+/- s.e.m.) NP-59 uptake was elevated (p less than 0.01) in both adrenalectomy and adrenal destruction groups, mean uptake (+/- s.e.m.) was 0.32% +/- 0.04% administered dose (95% Cl, 0.24%-0.4% administered dose) as compared to normal (0.16% +/- 0.05% administered dose, 95% Cl, 0.06%-0.26% administered dose). The remaining adrenal cortex may be anatomically abnormal after unilateral adrenalectomy and demonstrate compensatory, increased NP-59 uptake in the presence of overall, normal adrenocortical function.

Adosterol↗

Cellular internalization, transport, and esterification of iodine-125-NP59 by MA-10 Leydig tumor cells.

The present studies were directed toward understanding the cellular processing of the cholesterol analogue, NP59. NP59 readily entered MA-10 Leydig tumor cells. The cholesterol analogue entered the cells by binding to the plasma membrane and becoming internalized along with plasma membrane cholesterol. Internalized NP59 was readily esterified to NP59 ester. Transport of NP59 within the cell was indistinguishable from transport of cholesterol. Cholesterol and NP59 transport were under the control of cAMP, however, only cholesterol entered the mitochondria and was converted into progesterone. Thus, internalized NP59 could not be removed from the cell by conversion into steroid hormones. Esterified NP59 was metabolically inert and could not be converted back to free NP59 and free fatty acid. Since NP59 was not a substrate for the cholesteryl ester hydrolase, it became trapped in the cell as NP59 ester.

Adosterol↗

Adrenal cortical adenoma causing Cushing's syndrome: correct localization by functional scintigraphy despite nonlocalizing morphological imaging studies.

A 60-year-old woman with Cushing's syndrome in whom high-dose dexamethasone failed to suppress glucocorticoids was studied by ultrasound and CT. Neither of these morphological studies was interpreted as revealing any adrenal abnormality. Functional imaging with NP-59 (131-I-beta-iodomethylnorcholesterol) revealed unequivocal, intense, unilateral uptake in the left adrenal gland and subsequent surgery removed a 2.5 cm adrenocortical adenoma from this site. Following surgery the patient was temporarily adrenocortically insufficient but later returned to normal. It is unusual for adrenocortical adenomas causing Cushing's syndrome not to be correctly located by CT. NP-59 scintigraphy in addition to being highly accurate in the location of adrenocortical adenomas also has the advantage of correctly depicting bilateral cortical nodular hyperplasia in which CT will frequently reveal only the largest nodule, which may be incorrectly designated a unilateral adenoma. Furthermore, scintigraphy provides evidence of suppression of the contralateral, normal adrenal cortical tissue in Cushing's syndrome caused by an adrenal adenoma and predicts the vulnerability of such patients to postoperative adrenocortical insufficiency.

Adenoma↗

Diagnostic accuracy and pitfalls of [iodine-131]6-beta-iodomethyl-19-norcholesterol (NP-59) imaging.

NP-59 concentrates in steroid hormone synthesizing tissues, enabling scintigraphic localization and characterization of endocrine dysfunction in the adrenal cortex and ovary. Studying 108 consecutive cases from 1982 to 1985 and using clinical, biochemical, radiographic, and pathologic data, we performed a rigorous assessment of the accuracy and pitfalls of NP-59 scintigraphy. The evaluation was divided into categories of abnormal hormone secretion: Cushing's syndrome, primary aldosteronism, and hyperandrogenism. Additional categories included euadrenal tumors (without detectable hormone dysfunction) and sites of residual adrenal cortical tissue. The accuracy of NP-59 scintigraphy ranged from 71% in primary aldosteronism and 75% in euadrenal tumors, to 100% for Cushing's syndrome and hyperandrogenism. However, more than in most nuclear medicine studies, NP-59 imaging requires well-defined indications to be met for it to be efficacious, including the fulfillment of clear clinical, biochemical, and radiographic criteria. The high reproducibility of NP-59 scintigraphic interpretation was demonstrated when 40 random cases underwent interinstitutional exchange and through interobserver evaluation at the University of Michigan. Responses of 85/126 medical centers to questionnaires revealed the high level of NP-59 safety.

Adosterol↗

Scintigraphic localization of ovarian dysfunction.

To assess the potential role of scintigraphy in the evaluation of clinically and biochemically suspect ovarian hyperandrogenism (HA), dexamethasone suppression 131I-6 beta-iodomethyl-19-norcholesterol (NP-59) scans were performed to characterize ovarian function in nine patients. Pelvic ultrasound and/or computed tomography (CT) identified anatomic abnormalities in the adnexal region in six women in whom there was discernible pelvic accumulation(s) of NP-59. In the remaining three patients testosterone levels were normal or only slightly elevated and the NP-59 scan did not demonstrate abnormal adrenal or pelvic uptake. CT and/or ultrasound studies failed to demonstrate an abnormality in the pelvis suggesting excessive peripheral conversion or abnormal end organ sensitivity of androgen precursors as potential etiologies of their HA. In three women with androgen secreting lipoid tumors of the ovary, unilateral, pelvic NP-59 activity was noted; these tumors were subsequently resected. Two women with bilateral pelvic NP-59 uptake were later shown to have hyperthecosis with markedly asymmetric and enlarged ovaries. In one woman the extent of asymmetric NP-59 uptake was anticipated by the asymmetry of ovarian vein androgen levels at selective venous catheterization. In another woman with markedly asymmetric polycystic ovary disease, intense focal uptake of NP-59 localized to the side of the anatomically abnormal, enlarged ovary. Thus, our preliminary study reviews our experience to date and suggests that NP-59 scintigraphy may be used to localize both tumorous and nontumorous ovarian dysfunction in states of HA and virilization.

Adosterol↗