Diagnostic performance of photon-counting detector CT for differentiation between adrenal adenomas and metastases.

OBJECTIVES: Aim of this study was to assess the value of virtual non-contrast (VNC) reconstructions in differentiating between adrenal adenomas and metastases on a photon-counting detector CT (PCD-CT). MATERIAL AND METHODS: Patients with adrenal masses and contrast-enhanced CT scans in portal venous phase were included. Image reconstructions were performed, including conventional VNC (VNCConv) and PureCalcium VNC (VNCPC), as well as virtual monochromatic images (VMI, 40-90 keV) and iodine maps. We analyzed images using semi-automatic segmentation of adrenal lesions and extracted quantitative data. Logistic regression models, non-parametric tests, Bland-Altman plots, and a random forest classifier were used for statistical analyses. RESULTS: The final study cohort consisted of 90 patients (36 female, mean age 67.8 years [range 39-87]) with adrenal lesions (45 adenomas, 45 metastases). Compared to metastases, adrenal adenomas showed significantly lower CT-values in VNCConv and VNCPC (p = 0.007). Mean difference between VNC and true non-contrast (TNC) was 17.67 for VNCConv and 14.85 for VNCPC. Random forest classifier and logistic regression models both identified VNCConv and VNCPC as the best discriminators. When using 26 HU as the threshold in VNCConv reconstructions, adenomas could be discriminated from metastases with a sensitivity of 86.7% and a specificity of 75.6%. CONCLUSION: VNC algorithms overestimate CT values compared to TNC in the assessment of adrenal lesions. However, they allow a reliable discrimination between adrenal adenomas and metastases and could be used in clinical routine in near future with an increased threshold (e.g., 26 HU). Further (multi-center) studies with larger patient cohorts and standardized protocols are required. CLINICAL RELEVANCE STATEMENT: VNC reconstructions overestimate CT values compared to TNC. Using a different threshold (e.g., 26 HU compared to the established 10 HU), VNC has a high diagnostic accuracy for the discrimination between adrenal adenomas and metastases. KEY POINTS: • Virtual non-contrast reconstructions may be promising tools to differentiate adrenal lesions and might save further diagnostic tests. • The conventional and a new calcium-preserving virtual non-contrast algorithm tend to systematically overestimate CT-values compared to true non-contrast images. • Therefore, increasing the established threshold for true non-contrast images (e.g., 10HU) may help to differentiate between adrenal adenomas and metastases on contrast-enhanced CT.

Feasibility and effectiveness of a single-catheter approach for adrenal vein sampling in patients with primary aldosteronism.

BACKGROUND: Adrenal vein sampling (AVS) is the preferred method for subtyping patients with primary aldosteronism, while the procedure is technically challenging. This study evaluated the feasibility and effectiveness of a single-catheter approach for AVS. METHODS: A retrospective analysis of 106 consecutive patients who underwent AVS was performed to determine the procedural success and complication rates. Bilateral AVS procedures were performed using a single 5-Fr Tiger catheter with repeated manual reshaping. RESULTS: We successfully advanced the catheter into the bilateral adrenal veins of all patients and reached a 90.6% procedural success rate of AVS. The procedural period was 33.0 ± 8.2 min, the fluoroscopy period was 5.8 ± 1.7 min, and the diagnostic contrast used was 17.3 ± 5.5 ml. Only one patient (0.9%) had a hematoma at the femoral puncture site. No other complications were observed. The operation period gradually shortened as the cumulative number of operations increased. The number of procedures required to overcome the learning curve was about 33 cases. CONCLUSIONS: The single-catheter approach is feasible and effective for AVS. Moreover, this approach required a relatively short learning curve for an inexperienced trainee.

Reliability of adrenal computed tomography in predicting the functionality of adrenal incidentaloma.

BACKGROUND: Adrenal incidentaloma (AI) is an adrenal mass discovered accidentally during abdominal or chest imaging techniques not aimed to adrenal gland assessment. Guidelines suggested confirming the benignity of AI radiologically and excluding hormonal dysfunctions. This study evaluated the reliability of computed tomography (CT) scan radiological parameters in predicting the functionality of AI. PATIENTS AND METHODS: A cross-sectional study performed in Faiha Specialized Diabetes, Endocrine and Metabolism Centre from July 2017 to July 2018, involving 38 patients (23 females [60.5%]) harbouring 43 AI referred for evaluation. For all patients, we assessed history, physical examination, radiological parameters of AI by CT scan (native Hounsfield unit [HU]), maximum diameter and absolute percentage washout [APW] and blood investigations (glycated haemoglobin, adrenocorticotropic hormone, aldosterone, renin, aldosterone/renin ratio, normetanephrine, metanephrine, dehydroepiandrosterone sulphate, cortisol and 1 mg overnight dexamethasone suppression test). RESULTS: Native CT adrenal HU ≥18.5 was statistically significant seen in most functional AI (FAI) (P = 0.006), especially in patients with mild autonomous cortisol excess (MACE) and pheochromocytoma (PCC) with P = 0.02 in both. Maximum diameter was significantly high (≥40 mm) in PCC and congenital adrenal hyperplasia (CAH) (P = 0.018 and 0.008, respectively). APW was significantly < 60% only in PCC (P = 0.02). CONCLUSIONS: Native HU was the most significant radiological parameter in predicting the functionality of FAI, MACE and PCC, but not in CAH and aldosterone-producing adenoma. The maximum diameter was significant in predicting the PCC and CAH, whereas the APW was significant in predicting PCC only.

Hypercortisolism and primary aldosteronism caused by bilateral adrenocortical adenomas: a case report.

BACKGROUND: Co-existing Cushing's syndrome and primary aldosteronism caused by bilateral adrenocortical adenomas, secreting cortisol and aldosterone, respectively, have rarely been reported. Precise diagnosis and management of this disorder constitute a challenge to clinicians due to its atypical clinical manifestations and laboratory findings. CASE PRESENTATION: We here report a Chinese male patient with co-existing Cushing's syndrome and primary aldosteronism caused by bilateral adrenocortical adenomas, who complained of intermittent muscle weakness for over 3 years. Computed tomography scans revealed bilateral adrenal masses. Undetectable ACTH and unsuppressed cortisol levels by dexamethasone suggested ACTH-independent Cushing's syndrome. Elevated aldosterone to renin ratio and unsuppressed plasma aldosterone concentration after saline infusion test suggested primary aldosteronism. Adrenal venous sampling adjusted by plasma epinephrine revealed hypersecretion of cortisol from the left adrenal mass and of aldosterone from the right one. A sequential bilateral laparoscopic adrenalectomy was performed. The cortisol level was normalized after partial left adrenalectomy and the aldosterone level was normalized after subsequent partial right adrenalectomy. Histopathological evaluation of the resected surgical specimens, including immunohistochemical staining for steroidogenic enzymes, revealed a left cortisol-producing adenoma and a right aldosterone-producing adenoma. The patient's symptoms and laboratory findings resolved after sequential adrenalectomy without any pharmacological treatment. CONCLUSIONS: Adrenal venous sampling is essential in diagnosing bilateral functional adrenocortical adenomas prior to surgery. Proper interpretation of the laboratory findings is particularly important in these patients. Immunohistochemistry may be a valuable tool to identify aldosterone/cortisol-producing lesions and to validate the clinical diagnosis.

Histogram Analysis of Adrenal Lesions With a Single Measurement for 10th Percentile: Feasibility and Incremental Value for Diagnosing Adenomas.

OBJECTIVE: Our purpose was to assess whether histogram analysis of adrenal lesions from a single measurement of mean attenuation and SD, using a threshold of 10% of negative voxels, can replace voxel counting while maintaining diagnostic accuracy. MATERIALS AND METHODS: In a 4-year period, 325 adrenal lesions were detected on CT examinations of 308 consecutive patients. After exclusions, 91 patients with 108 lesions, including 20 malignant lesions and 88 adenomas (defined by histologic results or follow-up), were enrolled. Two observers retrospectively measured lesion size, mean attenuation value, and SD attenuation value and generated a pixel histogram. The 10th percentile (P10) was obtained from the conventional histogram analysis and was also calculated from the following formula: P10 = mean attenuation - (1.282 × SD). Diagnostic accuracies of the mean attenuation criterion, histogram analysis, and calculated 10th percentile were compared. RESULTS: The study group was composed of 74 patients with 88 adenomas and 17 patients with 20 malignant lesions, including seven adrenocortical carcinomas and 13 metastases; 93.1% of histograms showed normal distribution. The correlation between histogram analysis and calculated 10th percentile was 0.9827 and 0.9843 for reader 1 and 2 (p < 0.00001 for both). For both readers, sensitivity and specificity of the mean attenuation analysis were 65.9% (95% CI, 55.0-75.7%) and 100.0% (95% CI, 83.2-100%). The sensitivity and specificity of histogram analysis and calculated 10th percentile were the same, 87.5% (95% CI, 78.7-93.6%) and 95.0% (95% CI, 75.1-99.8%), for both readers. The increment increase in sensitivity was significant (p < 0.001), whereas the decrease in specificity was not (p = 0.15). CONCLUSION: For most adrenal lesions, the pixel attenuation has a gaussian distribution, allowing estimation of 10th percentile with a single measurement. The accuracy of histogram analysis and calculated 10th percentile outperformed the mean attenuation as a diagnostic criterion for nonfunctioning adenomas.

ACTH-independent Cushing's syndrome with bilateral cortisol-secreting adrenal adenomas: a case report and review of literatures.

BACKGROUND: Adrenocorticotropic hormone (ACTH)-independent Cushing's syndrome (CS) with bilateral cortisol-secreting adenomas has been rarely reported in the literatures. Precise recognition and management of this disorder constitute a challenge to clinicians due to the difficulty of exact location of the functional lesions. CASE PRESENTATION: We herein report a new case of a Chinese female patient with a complaint of exertional dyspnea for over 10 years. ACTH-independent CS was diagnosed based on undetectable ACTH and unsuppressed cortisol levels by dexamethasone. Computed tomography (CT) scan indicated bilateral adrenal masses, and adrenal venous sampling (AVS) adjusted by plasma aldosterone revealed hypersecretion of cortisol from both adrenal glands. Bilateral cortisol-secreting adrenal adenomas were suspected and confirmed by the postoperative pathology in subsequent two-step bilateral laparoscopic adrenalectomy. The symptoms and signs of CS relieved after surgery with continuous glucocorticoid replacement. CONCLUSIONS: AVS adjusted by plasma aldosterone could be a useful technique in diagnosing ACTH-independent CS with bilateral adrenal adenomas prior to surgery. And the aldosterone ratio could be used to confirm the success of adrenal vein cannulation in this situation.

Can Imaging Predict Subclinical Cortisol Secretion in Patients With Adrenal Adenomas? A CT Predictive Score.

OBJECTIVE: The aim of this study is to determine whether any correlation between CT findings and functional parameters exists to predict subclinical glucocorticoid secretion. MATERIALS AND METHODS: This is a retrospective database study of 55 patients with incidentally discovered adenomas, investigated through CT with an adrenal protocol, assessing diameters and attenuation values on the unenhanced and contrast-enhanced phases. Patients underwent blood cortisol and corticotropin evaluation and overnight dexamethasone suppression test (DST), in accordance with clinical recommendations. Cortisol levels higher than 50 nmol/L after DST identified subclinical cortisol secretion. We identified 28 subjects with lipid-rich nonsecreting adenomas, nine with lipid-rich secreting adenomas, 11 with lipid-poor nonsecreting adenomas, and seven with lipid-poor secreting adenoma. RESULTS: Cortisol levels after DST were significantly and positively related to mass diameters. At univariate analysis, maximum and minimum diameters and attenuation in the delayed phase were significantly related to the presence of secreting or nonsecreting adenoma; at multivariate analysis, only the minimum diameter and the attenuation in the venous phase entered the stepwise logistic regression. Similarly, minimum diameter and attenuation in the venous phase emerged also at the multivariate stepwise regression between radiologic parameters and cortisol levels after DST. The formula of the radiologic score computed by using the coefficients of the multivariate regression was as follows: (0.1914 × minimum diameter) + (0.0308 × enhanced attenuation). The diagnostic accuracy of this discriminatory score in differentiating secreting from nonsecreting adenomas was 84.9%, the sensitivity was 81.3%, and the specificity was 87.2%. Adenomas with scores greater than 7.59 were considered as secreting adenomas, and adenomas with scores less than 7.36 were considered as nonsecreting adenomas. CONCLUSION: This study shows that imaging parameters can predict subclinical cortisol hypersecretion in patients with adrenal adenomas.

Combined chemical shift imaging with early dynamic serial gadolinium-enhanced MRI in the characterization of adrenal lesions.

OBJECTIVE: The purpose of this study was to retrospectively evaluate early dynamic serial gadolinium-enhanced and chemical-shift imaging (CSI) MRI to distinguish benign from malignant adrenal tumors. MATERIALS AND METHODS: Between July 2007 and December 2011, 205 patients with 239 adrenal lesions (177 adenomas, 54 metastases, 5 pheochromocytomas, and 3 adrenal cortical carcinomas) underwent early dynamic serial gadolinium-enhanced MRI and CSI. CSI was assessed qualitatively and by calculating the adrenal index, and enhancement patterns were evaluated qualitatively and quantitatively. Statistical analyses were performed. RESULTS: Most adenomas exhibited either an arterial blush or homogeneous enhancement, whereas most metastases showed early peripheral or heterogeneous enhancement. Visualization of higher enhancement on arterial and venous phases enabled differentiation of adenomas from metastases in most cases. Moderate to high signal intensity drop on CSI was seen in 95.4% of adenomas and 14.8% of metastases. In lesions with this level of signal intensity drop, 87 of 88 lesions with a capillary blush were adenomas. Early dynamic serial imaging alone was a significant (p < 0.0001) indicator of nonadenoma (area under the curve [AUC], 0.912) with optimal sensitivity of 81% and specificity of 93% for differentiating adenomas from nonadenomas. Combined analysis (CSI and early dynamic serial imaging) was also significant (p < 0.0001 and p=0.0014, respectively) for diagnosing nonadenomas (AUC, 0.983) with optimal sensitivity of 94% and specificity of 98%. CONCLUSION: Early dynamic serial gadolinium-enhanced MRI aids in characterization of adrenal tumors, especially lesions that are categorized as indeterminate on the basis of CSI.

What is the role of CHCHD2 in adrenal tumourigenesis?

PURPOSE: CHCHD2 is an antiapoptotic mitochondrial protein acting through the BCL2/BAX pathway in various cancers. However, data on the regulatory role of CHCHD2 in adrenal tumourigenesis are scarce. METHODS: We studied the expression of CHCHD2, BCL2, and BAX in human adrenocortical tissues and SW13 cells. mRNA and protein levels were analyzed through qPCR and immunoblotting, respectively, in 16 benign adrenocortical neoplasms (BANs), along with their adjacent normal adrenal tissues (controls), and 10 adrenocortical carcinomas (ACCs). BCL2/BAX mRNA expression was also analyzed in SW13 cells after CHCHD2 silencing. MTS, flow cytometry and scratch assays were performed to assess cell viability, apoptosis, and invasion, respectively. RESULTS: BCL2 and CHCHCD2 mRNA and protein expression was increased in BANs compared to normal adrenal tissues whereas BAX was decreased. BAX and CHCHD2 mRNA and protein levels were significantly downregulated and upregulated, respectively, in ACCs compared with either BANs or controls. Expression of the studied genes was not different among cortisol-secreting and nonfunctional ACAs. No significant association was found between genes' expression and other established prognostic markers of ACCs patients. In vitro analysis showed that CHCHD2 silencing resulted in reduced cell viability and invasion as well as increased SW13 cells apoptosis. CONCLUSIONS: CHCHD2 expression seems to be implicated in adrenal tumourigenesis and its absence resulted to increased apoptosis in vitro. However, the exact mechanism of action and particularly its association with the BAX/BCL2 pathway needs to be further studied and evaluate whether it could be a protentional therapeutic target.

Differential diagnosis of adrenal adenomas and metastases using spectral parameters in dual-layer detector spectral CT.

OBJECTIVE: To assess the diagnostic value of spectral parameters in differentiating adrenal adenomas from metastases based on dual-layer detector spectral CT (DLSCT). MATERIALS AND METHODS: Patients with adenomas or metastases who underwent enhanced DLSCT of the adrenals were enrolled. The CT values of virtual non-contrast images (CTVNC), iodine density (ID) values, and Z-effective (Z-eff) values, the normalized iodine density (NID) values, slopes of spectral HU curves (s-SHC), and iodine-to-CTVNC ratios of the tumors were measured in each phase. Receiver operating characteristic (ROC) curves were used to compare the diagnostic values. RESULTS: Ninety-nine patients with 106 adrenal lesions (63 adenomas, 43 metastases) were included. In the venous phase, all spectral parameters were significantly different between adenomas and metastases (all p < 0.05). The combined spectral parameters showed a better diagnostic performance in the venous phase than in other phase (p < 0.05). The iodine-to-CTVNC value had a larger area under the ROC curve (AUC) than the other spectral parameters in the differential diagnosis of adenomas and metastases, with a diagnostic sensitivity and specificity of 74.4% and 91.9%, respectively. In the differential diagnosis of lipid-rich adenomas, lipid-poor adenomas and metastases, the CTVNC value and s-SHC value also had a larger AUC than the other spectral parameters, with a diagnostic sensitivity of 97.7%, 79.1% and specificity of 91.2%, 93.1%, respectively. CONCLUSION: On DLSCT, the combined spectral parameters in the venous phase could help better distinguish adrenal adenomas from metastases. The iodine-to-CTVNC, CTVNC and s-SHC values had the highest AUC values in differentiating adenomas, lipid-rich adenomas and lipid-poor adenomas from metastases, respectively.

Concomitant coexistence of ACTH-dependent and independent Cushing syndrome.

We report a case of a patient who presented for ACTH-dependent Cushing after a confirmed hypercortisolism and an inadequate normal ACTH. A transsphenoidal surgery of a pituitary picoadenoma has been done. After surgery, the patient showed the persistence of hypercortisolism. CT scan revealed adrenal adenomas removed surgically and improved the patient.

The Role of Immunohistochemical Markers for the Diagnosis and Prognosis of Adrenocortical Neoplasms.

Adrenal cortical carcinoma (ACC) is a rare cancer with poor prognosis that needs to be distinguished from adrenocortical adenomas (ACAs). Although, the recently developed transcriptome analysis seems to be a reliable tool for the differential diagnosis of adrenocortical neoplasms, it is not widely available in clinical practice. We aim to evaluate histological and immunohistochemical markers for the distinction of ACCs from ACAs along with assessing their prognostic role. Clinical data were retrospectively analyzed from 37 patients; 24 archived, formalin-fixed, and paraffin-embedded ACC samples underwent histochemical analysis of reticulin and immunohistochemical analysis of p27, p53, Ki-67 markers and were compared with 13 ACA samples. Weiss and Helsinki scores were also considered. Kaplan-Meier and univariate Cox regression methods were implemented to identify prognostic effects. Altered reticulin pattern, Ki-67% labelling index and overexpression of p53 protein were found to be useful histopathological markers for distinguishing ACAs from ACCs. Among the studied markers, only pathological p53 nuclear protein expression was found to reach statistically significant association with poor survival and development of metastases, although in a small series of patients. In conclusion, altered reticulin pattern and p53/Ki-67 expression are useful markers for distinguishing ACCs from ACAs. Immunohistopathology alone cannot discriminate ACCs with different prognosis and it should be combined with morphological criteria and transcriptome analysis.

Diagnostic efficacy of 18F-FDG PET/CT in patients with adrenal incidentaloma.

BACKGROUND: The management of adrenal incidentaloma is still a challenge with respect to determining its functionality (hormone secretion) and malignancy. In this light, we performed 18F-FDG PET/CT scan to assess the SUVmax values in different adrenal masses including Cushing syndrome, pheochromocytoma, primary hyperaldosteronism and non-functional adrenal adenomas. METHODS: Total 109 (73 F, 36 M) patients with adrenal mass (incidentaloma), mean age of 53.3 ± 10.2 years (range, 24-70) were screened by 18F-FDG PET/CT. Data of 18F-FDG PET/CT imaging of the patients were assessed by the same specialist. Adrenal masses were identified according to the calculated standardized uptake values (SUVs). Clinical examination, 24-h urine cortisol, catecholamine metabolites, 1-mg dexamethasone suppression test, aldosterone/renin ratio and serum electrolytes were analyzed. RESULTS: Based on the clinical and hormonal evaluations, there were 100 patients with non-functional adrenal mass, four with cortisol-secreting, four with pheochromocytomas and one with aldosterone-secreting adenoma. Mean adrenal mass diameter of 109 patients was 2.1 ± 4.3 (range, 1-6.5 cm). The 18F-FDG PET/CT imaging of the patients revealed that lower SUVmax values were found in non-functional adrenal masses (SUVmax 3.2) when compared to the functional adrenal masses including four with cortisol-secreting adenoma (SUVmax 10.1); four with pheochromcytoma (SUVmax 8.7) and one with aldosterone-secreting adenomas (SUVmax 3.30). Cortisol-secreting (Cushing syndrome) adrenal masses showed the highest SUVmax value (10.1), and a cut-off SUVmax of 4.135 was found with an 84.6% sensitivity and 75.6% specificity cortisol-secreting adrenal adenoma. CONCLUSIONS: Consistent with the similar studies, non-functional adrenal adenomas typically do not show increased FDG uptake and a certain form of functional adenoma could present various FDG uptake in FDG PET/CT. Especially functional adrenal adenomas (cortisol secreting was the highest) showed increased FDG uptake in comparison to the non-functional adrenal masses. Therefore, setting a specific SUVmax value in the differentiation of malignant adrenal lesion from the benign one is risky and further studies, including a high number of functional adrenal mass are needed.

Prevalence of Somatic KCNJ5 Mutations in Thai Patients With Aldosterone-Producing Adrenal Adenomas.

Somatic KCNJ5 mutations result in excess aldosterone production and are reported to be more common in Asia than elsewhere. To assess the prevalence of somatic KCNJ5 mutations in Thai patients with aldosterone-producing adrenal adenomas (APAs) in a single tertiary center, we analyzed the paraffin-embedded tissue of KCNJ5 mutations from 96 patients with sporadic APAs who underwent unilateral laparoscopic adrenalectomy at our center during 2007 to 2016. We also assessed the clinical characteristics, treatment outcomes, and biochemistry and histologic differences among patients with and without somatic KCNJ5 mutations. Of the 96 patients with APA, 67 (70%) had somatic mutations of the KCNJ5 gene: 39 patients with p.G151R, 26 patients with p.L168R, one patient with p.T158A, and one patient with p.W126R. All patients presented with hypertension. Hypokalemia was documented in 98% of patients. The hypertension cure rate at 1 year after surgery was 35%. Patients with somatic KCNJ5 mutations required more potassium supplementation and had adrenal histology compatible with zona fasciculata-like cells compared with patients without the mutations (all P < 0.05). There were no significant differences in preoperative plasma aldosterone concentration (PAC), plasma renin activity, aldosterone/renin ratio, potassium level, treatment of hypertension, tumor size, and hypertension cure rate among patients in the KCNJ5-mutant and nonmutant groups. In a multivariate analysis, a higher PAC was associated with the presence of somatic KCNJ5 mutations. In summary, the prevalence of somatic KCNJ5 mutations in patients with sporadic APAs in Thailand, an Asian country with residents of different ethnic backgrounds, is comparable to previous reports in Asia.

Tumoral angiogenesis in both adrenal adenomas and nonadenomas: a promising computed tomography biomarker for diagnosis.

To explore the correlation between the typical findings of dynamic contrast-enhanced computed tomography (DCE-CT) and tumoral angiogenesis (microvessel density [MVD] and vascular endothelial growth factor [VEGF]) in adenomas and nonadenomas such that the enhancement mechanism of DCE-CT in adrenal masses can be explained more precisely. Forty-two patients with 46 adrenal masses confirmed by surgery and pathology were included in the study; these masses included 23 adenomas, 18 nonadenomas, and 5 hyperplastic nodules. The findings of DCE-CT and angiogenesis in adrenal masses were studied. The features of DCE-CT in adenomas and nonadenomas were evaluated to determine whether the characteristics of DCE-CT in adrenal masses were closely correlated with tumoral angiogenesis. Adrenal adenomas were significantly different from nonadenomas in the time density curve and the mean percentage of enhancement washout at the 7-minute delay time in DCE-CT. The mean MVD and VEGF expression exhibited significant differences between the rapid washout group (types A and C) and the slow washout group (types B, D, and E) and between the relative washout (Washr) ≥34% and the absolute washout (Washa) ≥43% on the 7-minute enhanced CT scans (P=0.000). Adenomas were suggested when adrenal masses presented as types A and C, and/or the Washr ≥34%, and/or the Washa ≥43%, and the opposite was suggested for nonadenomas. These results showed a close correlation between the characteristics of DCE-CT and both MVD and VEGF expression in adrenal masses. There was also a significant difference in MVD and VEGF expression between adenomas and nonadenomas. In conclusion, MVD and VEGF expression are two important pathological factors that play important roles in the characterization of DCE-CT in adrenal masses because they cause different time density curve types, the Washr and the Washa for adrenal adenomas and nonadenomas.

Differentiation between adrenal adenomas and nonadenomas using dynamic contrast-enhanced computed tomography.

This study was performed to evaluate the findings including the time density curve (TD curve), the relative percentage of enhancement washout (Washr) and the absolute percentage of enhancement washout (Washa) at dynamic contrast-enhanced computed tomography (DCE-CT) in 70 patients with 79 adrenal masses (including 44 adenomas and 35 nonadenomas) confirmed histopathologically and/or clinically. The results demonstrated that the TD curves of adrenal masses were classified into 5 types, and the type distribution of the TD curves was significantly different between adenomas and nonadenomas. Types A and C were characteristic of adenomas, whereas types B, D and E were features of nonadenomas. The sensitivity, specificity and accuracy for the diagnosis of adenoma based on the TD curves were 93%, 80% and 87%, respectively. Furthermore, when myelolipomas were excluded, the specificity and accuracy for adenoma were 90% and 92%, respectively. The Washr and the Washa values for the adenomas were higher than those for the nonadenomas. The diagnostic efficiency for adenoma was highest at 7-min delay time at DCE-CT; Washr was more efficient than Washa. Washr ≥34% and Washa ≥43% were both suggestive of adenomas and, on the contrary, suspicious of nonadenomas. The sensitivity, specificity and accuracy for the diagnosis of adenoma were 84%, 77% and 81%, respectively. When myelolipomas were precluded, the diagnostic specificity and accuracy were 87% and 85%, respectively. Therefore, DCE-CT aids in characterization of adrenal tumors, especially for lipid-poor adenomas which can be correctly categorized on the basis of TD curve combined with the percentage of enhancement washout.