Strategies for subtyping primary aldosteronism.

Adrenal venous sampling (AVS) is a crucial method for the lateralization of primary aldosteronism (PA). It is advised to halt the use of the patient's antihypertensive medications and correct hypokalemia prior to undergoing AVS. Hospitals equipped to conduct AVS should establish their own diagnostic criteria based on current guidelines. If the patient's antihypertensive medications cannot be discontinued, AVS can be performed as long as the serum renin level is suppressed. The Task Force of Taiwan PA recommends using a combination of adrenocorticotropic hormone stimulation, quick cortisol assay, and C-arm cone-beam computed tomography to maximize the success of AVS and minimize errors by using the simultaneous sampling technique. If AVS is not successful, an NP-59 (131 I-6-ß-iodomethyl-19-norcholesterol) scan can be used as an alternative method to lateralize PA. We depicted the details of the lateralization procedures (mainly AVS, and alternatively NP-59) and their tips and tricks for confirmed PA patients who would consider to undergo surgical treatment (unilateral adrenalectomy) if the subtyping shows unilateral disease.

Evaluation of standardized uptake value on 131I-6ß-iodomethyl-19-norcholesterol scintigraphy for diagnosis of primary aldosteronism and correspondence with adrenal venous sampling.

PURPOSE: Adrenal venous sampling (AVS) is a reliable method for lateralization of adrenal hormone secretion, which is important for discriminating between aldosterone-producing adenoma and bilateral adrenal hyperplasia, both of which cause primary aldosteronism (PA). The aim of this study was to evaluate the diagnostic accuracy of the maximum and mean standardized uptake values (SUVmax and SUVmean, respectively) of 131I-6ß-iodomethyl-19-norcholesterol (NP-59) single-photon emission computed tomography (SPECT) for PA and its correspondence with AVS. METHODS: Adrenal NP-59 scintigraphy was performed in 14 patients with suspected PA, and AVS was also performed in 7 of them. SUVmax and SUVmean of the adrenal lesions on the dominant side and their ratios to the values on the non-dominant side (SUVRmax and SUVRmean, respectively) were calculated on SPECT images using ordered-subset conjugate gradient minimization (OSCGM) and three-dimensional ordered-subset expectation maximization (3D-OSEM) reconstruction algorithms. RESULTS: SUVmax and SUVmean on NP-59 SPECT images were significantly higher for aldosterone-producing adenoma than for bilateral adrenal hyperplasia or non-functioning adenoma and slightly superior to SUVRmax and SUVRmean (P = 0.0475 and P = 0.0447 vs. P = 0.124 and P = 0.132, respectively, with OSCGM). The respective areas under the receiver-operating characteristic curve for SUV and SUVR were 0.933 and 0.725 with OSCGM and 0.844 and 0.750 with 3D-OSEM, while SUVmax and SUVRmax had exactly the same diagnostic accuracy as SUVmean and SUVRmean. SUV and SUVR were associated with the diagnostic features on AVS and consistent with lateralization by AVS in most patients. CONCLUSION: In this study, SUV on NP-59 SPECT helped in the diagnosis of PA and was consistent with the results of AVS in nearly all cases.

NP-59 Adrenal Scintigraphy as an Imaging Biomarker to Predict KCNJ5 Mutation in Primary Aldosteronism Patients.

Purpose: Somatic KCNJ5 mutation occurs in half of unilateral primary aldosteronism (PA) and is associated with more severe phenotype. Mutation status can only be identified by tissue sample from adrenalectomy. NP-59 adrenal scintigraphy is a noninvasive functional study for disease activity assessment. This study aimed to evaluate the predictive value of NP-59 adrenal scintigraphy in somatic KCNJ5 mutation among PA patients who received adrenalectomy. Methods: Sixty-two PA patients who had NP-59 adrenal scintigraphy before adrenalectomy with available KCNJ5 mutation status were included. Two semiquantitative parameters, adrenal to liver ratio (ALR) and lesion to contralateral ratio of bilateral adrenal glands (CON) derived from NP-59 adrenal scintigraphy, of mutated and wild-type patients were compared. Cutoff values calculated by receiver-operating characteristic (ROC) analysis were used as a predictor of KCNJ5 mutation. Results: Twenty patients had KCNJ5 mutation and 42 patients were wild type. Patients harboring KCNJ5 mutation had both higher ALR and CON (p = 0.0031 and 0.0833, respectively) than wild-type patients. With ALR and CON cutoff of 2.10 and 1.95, the sensitivity and specificity to predict KCNJ5 mutation were 85%, 57% and 45%, 93%, respectively. Among 20 patients with KCNJ5 mutation, 16 showed G151R point mutation (KCNJ5- G151R) and 4 showed L168R point mutation (KCNJ5-L168R), which former one had significantly lower ALR (p=0.0471). Conclusion: PA patients harboring somatic KCNJ5 mutation had significantly higher NP-59 uptake regarding to ALR and CON than those without mutation. APAs with KCNJ5-L168R point mutation showed significantly higher ALR than those with KCNJ5-G151R point mutation.

Imaging of hepatic drug transporters with [131I]6-ß-iodomethyl-19-norcholesterol.

We examined whether [131I]6-ß-iodomethyl-19-norcholesterol (NP-59), a cholesterol analog, can be used to measure function of hepatic drug transporters. Hepatic uptake of NP-59 with and without rifampicin was evaluated using HEK293 cells expressing solute carrier transporters. The stability of NP-59 was evaluated using mouse blood, bile, and liver, and human liver S9. Adenosine triphosphate-binding cassette (ABC) transporters for bile excretion were examined using hepatic ABC transporter vesicles expressing multidrug resistance protein 1, multidrug resistance-associated protein (MRP)1-4, breast cancer resistance protein (BCRP), or bile salt export pump with and without MK-571 and Ko143. Single photon emission computed tomography (SPECT) was performed in normal mice injected with NP-59 in the presence or absence of Ko143. Uptake of NP-59 into HEK293 cells expressing organic anion transporting polypeptide (OATP)1B1 and OATP1B3 was significantly higher than that into mock cells and was inhibited by rifampicin. NP-59 was minimally metabolized in mouse blood, bile, and liver, and human liver S9 after 120 min of incubation. In vesicles, NP-59 was transported by MRP1 and BCRP. Excretion of NP-59 into bile via BCRP was observed in normal mice with and without Ko143 in the biological distribution and SPECT imaging. NP-59 can be used to visualize and measure the hepatic function of OATP1B1, OATP1B3, and BCRP.

NP-59 test for preoperative localization of primary hyperaldosteronism.

PURPOSE: Adrenal venous sampling is generally considered the gold standard to identify unilateral hormone production in cases of primary hyperaldosteronism. The aim of this study is to evaluate whether the iodine-131-6-ß-iodomethyl-19-norcholesterol (NP-59) test may represent an alternative in selected cases. METHODS: Patients submitted to laparoscopic adrenalectomy for suspected primary hyperaldosteronism (n = 27) were retrospectively reviewed. When nuclear medicine tests were preoperatively performed, their results were compared with the histopathologic findings and clinical improvement. RESULTS: Nuclear medicine tests were realized in 13 patients. In 11 (84.6%), a planar anterior and posterior NP-59 scintigraphy was performed and a SPECT/TC in two (15.4%). Scintigraphy indicated a preoperative lateralization in 12 out of 13 patients (92.3%). When the value of NP-59 tests was based on pathologic results, it showed a sensitivity of 90.9% and a positive predictive value of 83.3%. When the nuclear medicine test's performance was based on postoperative blood pressure control, both sensitivity and positive predictive value were 91.6%. CONCLUSIONS: Nuclear medicine tests represent a useful tool in the preoperative localisation of primary hyperaldosteronism with a high sensitivity and positive predictive value. In patients with contraindications to adrenal venous sampling like contrast allergies, or when it is inconclusive, scintigraphy can represent a useful and non-invasive alternative.

Hormonal, Radiological, NP-59 Scintigraphy, and Pathological Correlations in Patients With Cushing's Syndrome Due to Primary Pigmented Nodular Adrenocortical Disease (PPNAD).

CONTEXT: Primary pigmented nodular adrenocortical disease (PPNAD) is a rare cause of ACTH-independent Cushing's syndrome that may occur in an isolated form or as part of Carney complex. The diagnosis of this disease can be difficult preoperatively because computed tomography (CT) scan can be normal or suggest unilateral adrenal lesion, which can impede the correct diagnosis of bilateral adrenal disease. OBJECTIVE: The aim of our study was to describe the results of preoperative imaging (adrenal [6ß-(131)I]iodomethyl-19-norcholesterol] [NP-59] scintigraphy and standard adrenal CT scan) and their correlations with clinical, pathological, and genetics investigations in patients with PPNAD. PATIENTS AND METHODS: Seventeen patients with ACTH-independent syndrome due to PPNAD were investigated with a standard adrenal CT scan and NP-59 scintigraphy. Hormonal, pathological, and genetics data were analyzed. RESULTS: Four males and 13 females (median age, 27 y) were included. PPNAD was isolated in 11 patients (with PRKAR1A mutation, n = 7; and without PRKAR1A mutation, n = 4) and was associated with extra-adrenal manifestations of Carney complex in six patients (with PRKAR1A mutation, n = 4; and without PRKAR1A mutation, n = 2). Standard adrenal CT scan revealed micronodules in 11 patients, macronodules in three patients, and was normal in three patients. All patients demonstrated bilateral adrenal radiocholesterol uptake. Adrenal uptake was asymmetrical in 10 of 17 patients (59%). Asymmetrical uptake correlated with the presence of macronodules at pathological analysis (P = .03). CONCLUSION: Standard adrenal CT scan most often reveals micronodules but there is no specific CT imaging. NP-59 scintigraphy always shows a bilateral adrenal uptake confirming the bilateral nature of the disease, but asymmetrical scintigraphic uptake can be observed in patients with macronodules.

Adrenal (131)I-6ß-iodomethylnorcholesterol scintigraphy in choosing the side for adrenalectomy in bilateral adrenal tumors with subclinical hypercortisolemia.

PURPOSE: Adrenal scintigraphy with 131I-6ß-iodomethylnorcholesterol is considered by several authors the gold standard for assessing tumors with subclinical hypercortisolemia. However, most of the described series consist mainly of cases with unilateral lesions. The aim of our study was to assess whether scintigraphy is useful in choosing the adrenalectomy side in the case of bilateral adrenal tumors with subclinical hypercortisolemia. METHODS: The study focused on 15 consecutive patients with benign bilateral adrenal tumors and subclinical hypercortisolemia. The scintigraphy with 131I-6ß-iodomethylnorcholesterol was performed. Fourteen patients underwent unilateral adrenalectomy; the gland with predominant uptake on scintigraphy was removed. Cortisol and ACTH concentrations were measured one and six months after surgery. Post-dexamethasone cortisolemia was assessed six months after surgery. To date, the patients have been under postoperative observation for 1-4 years. RESULTS: Four patients showed unilateral uptake of radiotracer, and nine patients showed predominant accumulation of radiotracer in one of the adrenal glands. The smaller tumor was predominant in 2 cases. Percentage of activity on the predominant side correlates positively with the difference between tumors' diameters. Unilateral uptake of radiotracer predicts long-lasting postoperative insufficiency of the second adrenal gland. Excision of predominating tumor led to cessation of hypercortisolemia in all patients. CONCLUSIONS: The corticoadrenal scintigraphy is useful in choosing the side for operation in the case of bilateral adrenal tumors with subclinical hypercortisolemia.

Long-term study of subclinical Cushing's syndrome shows high prevalence of extra-adrenal malignancy in patients with functioning bilateral adrenal tumors.

Subclinical Cushing's syndrome (SCS) is characterized by subtle autonomous cortisol secretion from adrenal tumors without specific signs and symptoms of hypercortisolism. Patients with SCS have a high prevalence of "lifestyle-related diseases," such as hypertension, diabetes mellitus, dyslipidemia, and osteoporosis. Long-term follow-up of SCS patients is reportedly indispensable for establishing indications for surgical treatment of SCS. We performed a follow-up survey of 27 patients with SCS (median: 5.3 years) and compared those who had undergone surgical treatment (n=15) with those who had not (n=12). The mean diameter of tumors was 31 mm; 16 (59%) patients had unilateral lesions and 11 (41%) carried bilateral ones. In 67% and 60% of the treatment group, respectively, hypertension and diabetes mellitus improved. We also noticed that eight of 11 (73%) SCS patients with bilateral adrenal tumors had extra-adrenal malignancies in various tissues. Interestingly, among nine SCS patients who had malignancies, eight showed bilateral adrenal uptake in ¹³¹I-aldosterol scintigraphy. The results imply that surgical treatment can reduce cardiovascular risks in SCS patients. Screening for malignancy may be necessary in patients with bilateral adrenal tumors suspected of autonomous hypersecretion of cortisol from both sides.

Prognostic value of semiquantification NP-59 SPECT/CT in primary aldosteronism patients after adrenalectomy.

PURPOSE: Primary aldosteronism (PA), characterized by an excessive production of aldosterone, affects 5-13 % of patients with hypertension. Accurate strategies are needed for the timely diagnosis of PA to allow curability and prevention of excessive cardiovascular events and related damage. This study aimed to evaluate the usefulness of semiquantification of (131)I-6ß-iodomethyl-norcholesterol (NP-59) single photon emission computed tomography (SPECT)/CT in differentiating aldosterone-producing adenoma (APA) from idiopathic adrenal hyperplasia (IAH) and in predicting clinical outcomes after adrenalectomy. METHODS: We retrospectively reviewed 49 PA patients who had undergone adrenalectomy after NP-59 SPECT/CT within 1 year. A conventional visual scale (VS) and two semiquantitative parameters generated from SPECT/CT, adrenal to liver ratio (ALR) and lesion to contralateral ratio of bilateral adrenal glands (CON), with cutoff values calculated by receiver-operating characteristic (ROC) analysis, were compared with pathology results and postsurgical outcomes to determine the accuracy. RESULTS: An ALR cutoff of 1.84 and a CON cutoff of 1.15 showed an ability to distinguish adenoma from hyperplasia similar to VS (p = 0.2592 and 0.1908, respectively). An ALR cutoff of 2.28 and a CON cutoff of 1.11 yielded the highest sensitivity and specificity to predict postsurgical outcomes, and an ALR of 2.28 had an ability superior to VS (p = 0.0215), while a CON of 1.11 did not (p = 0.1015). Patients with either ALR or CON greater than the cutoff had a high probability of positive postsurgical outcomes (n = 36/38), while patients with both ALR and CON less than the cutoff had a low probability of positive postsurgical outcomes (n = 2/11). CONCLUSION: Semiquantification of NP-59 scintigraphy has an ability similar to VS in differentiating APA from IAH, but an excellent ability to predict postsurgical outcomes of adrenalectomy. An ALR or CON greater than the cutoff strongly suggests benefits from adrenalectomy, and both ALR and CON less than the cutoff implies a reduced chance of improvement in postsurgical outcome.

Is there a role for Nuclear Medicine in diagnosis and management of patients with primary aldosteronism?

Primary aldosteronism (PA) is the most common cause of secondary hypertension. The diagnosis of PA is of clinical importance for choosing the appropriate treatment, meaning, surgery for the unilateral disease, and inclusion of aldosterone antagonists in the antihypertensive treatment for the bilateral disease. Current diagnostic approaches showed that the prevalence of PA is much higher than previously estimated. There is still controversy regarding the true prevalence of PA in hypertensive patients. The gold standard for differentiating between unilateral and bilateral disease is the adrenal vein sampling (AVS), a method that is invasive and is performed accurately in only few dedicated centers. Non invasive methods (imaging) for discriminating the two entities are: the CT scan, MRI and iodocholesterol (NP-59) scintigraphy performed under dexamethasone suppression. But the accuracy of imaging compared to AVS is suboptimal and can result in wrong therapeutic decisions. NP-59 scintigraphy is a non-invasive functional imaging technique that reveals the adrenal cortical autonomic function and could have of incremental value over anatomical imaging. In conclusion, in previous years NP-59 scintigraphy was used infrequently, but recently with the advent of hybrid single photon emission tomography (SPET/CT) systems the interest in NP-59 scintigraphy has been renewed. Studies comparing NP-59 SPET/CT imaging with AVS are warranted in order to establish its diagnostic accuracy.

Diagnosis of primary aldosteronism in chronic kidney disease by I-131 NP-59 SPECT/CT imaging.

Primary aldosteronism (PA) may be missed in patients with chronic kidney disease (CKD), because CKD may disturb the renin-angiotensin-aldosterone system. Adrenal vein sampling has increased risks in patients with CKD. We report the case of a 58-year-old man with CKD and suspected PA. Left adrenal aldosteronism was diagnosed by NP-59 SPECT/CT. Left adrenalectomy demonstrated adrenocortical nodular hyperplasia. Plasma aldosterone normalized and blood pressure stabilized after surgery. NP-59 SPECT/CT may be a helpful diagnostic tool for detecting and lateralizing PA in CKD patients.

Diagnostic value of I-131 NP-59 SPECT/CT scintigraphy in patients with subclinical or atypical features of primary aldosteronism.

Accumulating evidence has shown the adverse effect of long-term hyperaldosteronism on cardiovascular morbidity that is independent of blood pressure. However, the diagnosis of primary aldosteronism (PA) remains a challenge for patients who present with subtle or atypical features or have chronic kidney disease (CKD). SPECT/CT has proven valuable in the diagnosis of a number of conditions. The aim of this study was to determine the usefulness of I-131 NP-59 SPECT/CT in patients with atypical presentations of PA and in those with CKD. The records of 15 patients with PA were retrospectively analyzed. NP-59 SPECT/CT was able to identify adrenal lesion(s) in CKD patients with suspected PA. Patients using NP-59 SPECT/CT imaging, compared with those not performing this procedure, significantly featured nearly normal serum potassium levels, normal aldosterone-renin ratio, and smaller adrenal size on CT and pathological examination and tended to feature stage 1 hypertension and non-suppressed plasma renin activity. These findings show that noninvasive NP-59 SPECT/CT is a useful tool for diagnosis in patients with subclinical or atypical features of PA and those with CKD.

Noninvasive adrenal imaging in hyperaldosteronism: is it accurate for correctly identifying patients who should be selected for surgery?

BACKGROUND AND AIMS: The most common causes of hyperaldosteronism (HA) are bilateral idiopathic hyperaldosteronism (IHA), aldosterone-producing adenoma (APA), and unilateral primary adrenal hyperplasia (PAH). We evaluated if non-invasive preoperative imaging studies are able to reliably differentiate these causes of hyperaldosteronism. METHODS: The medical records of 50 consecutive patients with HA were reviewed. Follow up was obtained by outpatient consultation or phone contact. RESULTS: Thirty-five patients (70%) underwent successful adrenalectomy for APA, basing on the computed tomography (CT) scan results only. All these patients were biochemically cured. The remaining 15 patients underwent dexamethasone suppression adrenal cortical scintiscan (ACS) because of equivocal or inconclusive CT scan. In 11 of these patients, ACS showed a bilateral uptake, suggesting IHA. They were followed-up. In the remaining four patients, ACS showed a unilateral uptake. These patients underwent adrenalectomy. Final histology showed APA in three patients and PAH in one. They were biochemically cured. Sensitivity of combined non-invasive imaging procedures (CT and ACS) in detecting histologically proven and biochemically cured APA and PAH was 100%. CONCLUSION: Non-invasive adrenal imaging studies are accurate in distinguishing between IHA and APA/PAH. Invasive diagnostic tests (adrenal venous sampling) should be indicated only when they do not conclusively localize hypersecretion.

Unusual visualization of an adrenal carcinoma on NP-59 scintiscan.

[Iodine-131]6-beta-iodomethylnorcholesterol (NP-59) visualization of adrenocortical carcinoma is unusual. We describe a 17-year-old female with virilization and elevated plasma testosterone, dehydroepiandrosterone sulfate (DHEAS) and aldosterone. Magnetic resonance imaging disclosed a 9-cm right adrenal mass. NP-59 adrenal scanning displayed unilateral uptake of tracer and no visualization of the contralateral adrenal gland. Exploratory laparotomy revealed adrenocortical carcinoma. Subsequent immunohistochemical studies confirmed that the tumor was capable of producing a mixture of steroids, including testosterone, DHEAS and aldosterone. Visualization of an adrenal tumor on NP-59 scintiscan is an unusual finding, which cannot exclude the possibility of malignancy.

[Preoperative diagnostics in patients with adrenal tumors]. / Diagnostyka przedoperacyjna u chorych z guzami nadnerczy.

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.

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.