The diagnostic role of radionuclide imaging in evaluation of patients with nonhypersecreting adrenal masses. (1/10)The aim of this study was to evaluate the role of radionuclide imaging in the characterization of nonhypersecreting adrenal masses. METHODS: A total of 54 patients (19 men, 35 women; mean age, 50 +/- 16 y) with nonhypersecreting unilateral adrenal tumors that had been originally detected on CT or MRI underwent adrenal scintigraphy using different radiotracers. None of the patients showed specific symptoms of adrenal hypersecretion. Screening tests for excess cortical and medullary products showed normal adrenal hormone levels. Radionuclide studies (n = 73) included (131)I-norcholesterol (n = 24), (131)I-metaiodobenzylguanidine (MIBG) (n = 23), and (18)F-FDG PET (n = 26) scans. RESULTS: Histology after surgery (n = 31) or adrenal biopsy (n = 23) was obtained. Adrenal lesions were represented by 19 adenomas, 4 cysts, 1 myelolipoma, 1 neurinoma, 2 ganglioneuromas, 5 pheochromocytomas, 4 pseudotumors, 6 carcinomas, 2 sarcomas, and 10 metastases (size range, 1.5- to 5-cm diameter; mean, 4.9 +/- 3.1 cm). For norcholesterol imaging, diagnostic sensitivity, specificity, and accuracy were 100%, 71%, and 92%, respectively; the positive predictive value (PPV) of the norcholesterol scan to characterize an adrenal mass as an adenoma was 89%, whereas the corresponding negative predictive value (NPV) to rule out this type of tumor was 100%. For MIBG imaging, diagnostic sensitivity, specificity, and accuracy were 100%, 94%, and 96%, respectively; the PPV of the MIBG scan to characterize an adrenal mass as a medullary chromaffin tissue tumor was 83%, whereas the corresponding NPV to rule out this type of tumor was 100%. For FDG PET, diagnostic sensitivity, specificity, and accuracy were 100%, 100%, and 100%, respectively; the PPV of FDG PET to characterize an adrenal mass as a malignant tumor was 100%, whereas the corresponding NPV to rule it out was 100%. Furthermore, in 7 patients with malignant adrenal tumors, FDG whole-body scanning revealed extra-adrenal tumor sites (n = 29), allowing an accurate diagnosis of the disease's stage using a single-imaging technique. CONCLUSION: In patients with nonhypersecreting adrenal masses, radionuclide adrenal imaging, using specific radiopharmaceuticals such as norcholesterol, MIBG, and FDG, may provide significant functional information for tissue characterization. Norcholesterol and MIBG scans are able to detect benign tumors such as adenoma and pheochromocytoma, respectively. Conversely, FDG PET allows for recognition of malignant adrenal lesions. Therefore, adrenal scintigraphy is recommended for tumor diagnosis and, hence, for appropriate treatment planning, particularly when CT or MRI findings are inconclusive for lesion characterization. (+info)
SPECT semiquantitative analysis of adrenocortical (131)I-6 beta iodomethyl-norcholesterol uptake to discriminate subclinical and preclinical functioning adrenal incidentaloma. (2/10)The goal of this study was to evaluate the clinical reliability of the (131)I-6 beta-iodomethyl-norcholesterol ((131)I-NP-59) uptake semiquantitative evaluation method we propose for the characterization of adrenocortical masses in a selected population of patients with disease clinically classified as subclinical (SC) and preclinical (PC) Cushing's syndrome (CS) according to Reincke's definition. METHODS: Forty-seven consecutive patients with incidentally discovered unilateral adrenal masses were examined by a triple-head SPECT system after intravenous injection of (131)I-NP-59. Abdominal SPECT was performed at 24, 48, 72, and, in selected cases, 96 h after tracer injection. Connected with adrenals and liver, a standard elliptic region of interest (ROI) was manually drawn, taking care to avoid the gallbladder region. The adrenal ROI integral count, obtained by summing the 24-, 48-, and 72-h counting values, was normalized by the hepatic integral count. Subsequently, the adrenal percentage of relative uptake (UPT%) was computed. RESULTS: Discriminant analysis was performed on the variables UPT%, adrenocorticotropic hormone (ACTH) serum concentration, and CT mass dimension (CTMD) to determine the variable, or combination thereof, best discriminating between the SC-CS and PC-CS groups. Compared with both ACTH and CTMD variables, univariate analysis confirmed the UPT% variable as the most significant to discriminate between these 2 clinical groups. In fact, UPT% alone correctly classified 8 of 9 patients in the SC-CS group and 20 of 22 patients in the PC-CS group with 95% positive and 80% negative predictive values and with overall accuracy, sensitivity, and specificity equal to 90%, 91%, and 89%, respectively. When all 3 variables were submitted to stepwise discriminant analysis, the derived classification matrix, after cross-validation, correctly classified 9 of 9 patients in the SC-CS group and 18 of 22 patients in the PC-CS group with 100% positive and 69% negative predictive values and with overall accuracy, sensitivity, and specificity equal to 87%, 82%, and 100%, respectively. CONCLUSION: According to these initial results, use of the proposed semiquantitative approach associated with both laboratory screening for cortisol production and CTMD measure seems to be able to increase the clinical diagnostic accuracy of PC-CS. This approach could be used in the follow-up of adrenal mass function every time hormonal or clinical features are suggestive of adrenocortical hyperfunction. (+info)
Imaging characterization of non-hypersecreting adrenal masses. Comparison between MR and radionuclide techniques. (3/10)AIM: In patients with non-hypersecreting adrenal masses, tumor characterization is clinically relevant to establish the appropriate treatment planning. The aim of this study was to comparatively characterize such adrenal lesions using MR and radionuclide techniques. METHODS: Thirty patients with non-hypersecreting unilateral adrenal tumors underwent both MR and adrenal scintigraphy. MR was performed using SE T1- (pre- and post-gadolinium DTPA) and T2-weighted images as well as in- and out-phase chemical-shift imaging (CSI). MR qualitative and quantitative (signal intensity ratios) evaluation was performed. Radionuclide studies consisted of iodine-131 nor-cholesterol (n=20), iodine-131 MIBG (n=15) and fluorine-18 FDG PET (n=11) scans. Histology (n=16), biopsy (n=3) or clinical-imaging follow-up (n=11) demomstrated 13 adenomas, 3 cysts, 2 myelolipomas, 4 pheochromocytomas (pheos), 4 carcinomas, 1 sarcoma and 3 metastases. Comparative imaging analysis was focused on adenomas, pheos and malignant tumors. RESULTS: Qualitative MR evaluation showed: signal T2-hyperintensity in 46% of adenomas and in 100% of pheos and malignant tumors, no gadolinium enhancement in 92% of adenomas and definite signal intensity loss on CSI in 100% of such tumor lesions, gadolinium enhancement in 100% of pheos and in 63% of malignancies and no absolute change of signal intensity on CSI in 100% of both pheos and malignancies. Quantitative MR analysis demonstrated: significantly higher signal T2-hyperintensity of pheos compared to adenomas and malignancies as well as significantly higher enhancement after gadolinium in pheos compared to adenomas and malignancies (p<0.03). Radionuclide studies showed significantly increased nor-cholesterol uptake only in adenomas (n=13), significant MIBG accumulation only in pheos (n=4) and FDG activity only in malignant adrenal lesions (n=8). CONCLUSION: MR techniques may provide some presumptive criteria to characterize non-hypersecreting adrenal masses, such as no gadolinium enhancement and definite signal intensity loss on CSI in adenomas or quantitatively measured T2-hyperintensity and gadolinium enhancement in pheos. On the other hand, radionuclide modalities offer more specific findings in this setting since nor-cholesterol and MIBG scans are respectively able to reveal benign tumors such as adenoma and pheochromocytoma, while FDG imaging allows identification of malignant adrenal lesions. Adrenal scintigraphy is recommended in those patients, when MR images are uncertain or inconclusive. (+info)
Tomographic evaluation of [131I] 6beta-iodomethyl-norcholesterol standardised uptake trend in clinically silent monolateral and bilateral adrenocortical incidentalomas. (4/10)AIM: The aim of this study was three-fold: 1) to quantify [131I]-6beta-iodomethyl-norcholesterol ([131I]-NP-59) adrenal uptake trend in patients with incidentalomas, 2) to identify a specific uptake trend (TREND) capable of characterising pre-clinical Cushing syndrome (PC-CS) patients, 3) to assess the clinical availability of TREND as a prognostic factor of late clinical outcome in a cohort of patients with bilateral adrenal adenomas. METHODS: Fifty-seven consecutive patients were examined using three-head SPECT at 24, 48, 72 hours following intravenous injection of [131I ]-NP-59. On the basis of the absence or presence of hormonal abnormalities, the selected population was classified as GR1 or GR2, respectively. Adrenal glands were classified into 4 groups taking into account both the patient group (GR1, GR2) and the presence (+) or absence (-) of the adenoma (AD) on CT scan. Using ROI technique, adrenal-liver uptake ratio (A/L) was estimated bilaterally at 24, 48 and 72 hours. For each adrenal group, mean [131I]-NP-59 uptake trends were derived. RESULTS: TREND was significantly different between GR1/AD+ and GR2/AD+. Among GR2/AD+ patients, TREND correctly identified PC-CS with a global accuracy of 74%. Two patients with bilateral incidentaloma developed an overt CS. In both patients, TREND correctly identified the hyperfunctioning adrenal, thus permitting an effective sparing adrenalectomy. CONCLUSIONS: TREND seems to be a parameter which closely reflects adrenal physiological behaviour, especially in the case of bilateral adrenal involving. The possibility to quantify even contralateral adrenal uptake as standardised index provides additional useful information about normal adrenal parenchyma and, indirectly, about adenoma functional autonomy. (+info)
131I-6beta-iodomethyl-19-norcholesterol SPECT/CT for primary aldosteronism patients with inconclusive adrenal venous sampling and CT results. (5/10)(+info)
Limited significance of asymmetric adrenal visualization on dexamethasone-suppression scintigraphy. (6/10)To assess whether a single measurement of the adrenal uptake of 6 beta-[131I]-iodomethylnorcholesterol (NP-59) on constant dexamethasone suppression would allow discrimination of adenoma from normal and bilateral hyperplasia, the adrenal uptake of 6 beta-[131I]iodomethylnorcholesterol (NP-59) was determined in 50 patients with primary aldosteronism (30 adenoma, 20 hyperplasia) and in 13 with hyperandrogenism (six adenoma, seven hyperplasia). Bilateral adrenal NP-59 activity at 5 days was seen in 14 of 36 patients with adenoma (normal to adenoma ratio of greater than or equal to 0.5), whereas marked asymmetric uptake of NP-59 was seen in six of 27 patients with hyperplasia (uptake ratio of less than or equal to 0.5). Thus the level of adrenal NP-59 uptake does not alone serve to distinguish either adenoma from the normal, contralateral adrenal or the adrenal glands in bilateral hyperplasia in all cases. It appears that the pattern of adrenal imaging, early unilateral or early bilateral NP-59 activity (less than 5 days after NP-59 on 4 mg dexamethasone), best serves to separate adrenal adenoma from bilateral hyperplasia. (+info)
Concentration of radiolabeled cholesterol in a feminizing adenoma of the testis. (7/10)Quantitative tissue studies demonstrated increased 19-[131I]-iodocholesterol concentration in a feminizing adenoma of the testis. The potential application of iodocholesterol and its isomers in the detection of steroid-secreting neoplasms of the testis and ovary is suggested. (+info)
Value of bowel preparation in adrenocortical scintigraphy with NP-59. (8/10)The use of radiolabeled cholesterol derivatives for functional imaging of the adrenal cortex may be rendered inaccurate or impossible because of the excretion of activity by the liver and its subsequent appearance in the colon. A simple bowel preparation (bisacodyl 5 or 10 mg nightly) significantly reduced bowel background activity during 6 beta-[I-131]iodomethyl-19-norcholesterol (NP-59) adrenal cortical scintigraphy. Activity interfering with image interpretability was present less frequently in patients taking bisacodyl: three days after injection 22% compared with 59%; five days after injection 23% compared with 35%. As bisacodyl acts only on the colon and does not disturb the enterohepatic circulation of cholesterol or bile acids, it is ideal for use with a tracer of cholesterol metabolism. (+info)
19-Iodocholesterol is a radiolabeled compound that is commonly used in medical imaging studies, particularly in nuclear medicine. It is a derivative of cholesterol, with an iodine atom added to the 19th carbon position. When administered to a patient, 19-iodocholesterol is taken up by the liver and incorporated into bile acids. The bile acids are then excreted into the small intestine, where they can be absorbed into the bloodstream and transported to various organs and tissues. In nuclear medicine imaging studies, 19-iodocholesterol is often used to evaluate the function of the liver and bile ducts. It can be injected into the bloodstream and imaged using a gamma camera to detect the distribution and uptake of the compound in the liver and bile ducts. This information can be used to diagnose and monitor conditions such as liver disease, bile duct obstruction, and gallstones.
Adrenal gland diseases refer to a group of medical conditions that affect the adrenal glands, which are small endocrine glands located on top of the kidneys. The adrenal glands produce hormones that regulate various bodily functions, including metabolism, blood pressure, and the stress response. Adrenal gland diseases can be classified into two main categories: primary adrenal gland diseases and secondary adrenal gland diseases. Primary adrenal gland diseases occur when there is a problem with the adrenal glands themselves, such as an adrenal tumor, adrenal insufficiency, or Addison's disease. These conditions can cause a range of symptoms, including fatigue, weight loss, low blood pressure, and electrolyte imbalances. Secondary adrenal gland diseases occur when there is a problem with another gland or organ that affects the adrenal glands, such as a pituitary tumor or a problem with the thyroid gland. These conditions can also cause a range of symptoms, including high blood pressure, weight gain, and electrolyte imbalances. Treatment for adrenal gland diseases depends on the underlying cause and the severity of the symptoms. In some cases, medications may be used to regulate hormone levels, while in other cases, surgery or other medical procedures may be necessary.
Iodine radioisotopes are radioactive forms of the element iodine that are used in medical imaging and treatment procedures. These isotopes have a nucleus that contains an odd number of neutrons, which makes them unstable and causes them to emit radiation as they decay back to a more stable form of iodine. There are several different iodine radioisotopes that are commonly used in medical applications, including iodine-123, iodine-125, and iodine-131. Each of these isotopes has a different half-life, which is the amount of time it takes for half of the radioactive material to decay. The half-life of an iodine radioisotope determines how long it will remain in the body and how much radiation will be emitted during that time. Iodine radioisotopes are often used in diagnostic imaging procedures, such as thyroid scans, to help doctors visualize the structure and function of the thyroid gland. They may also be used in therapeutic procedures, such as radiation therapy, to treat thyroid cancer or other thyroid disorders. In these cases, the radioactive iodine is administered to the patient and selectively absorbed by the thyroid gland, where it emits radiation that damages or destroys cancerous cells.