Clinical and imaging presentations are associated with function in incidental adrenocortical adenomas: a retrospective cohort study.

OBJECTIVE: The aim of this study is to assess whether clinical and imaging characteristics are associated with the hormonal subtype, growth, and adrenalectomy for incidental adrenal cortical adenomas (ACAs). DESIGN: This is a single-center cohort study. METHODS: Consecutive adult patients with incidental ACA were diagnosed between 2000 and 2016. RESULTS: Of the 1516 patients with incidental ACA (median age 59 years, 62% women), 699 (46%) had nonfunctioning adenomas (NFAs), 482 (31%) had mild autonomous cortisol secretion (MACS), 62 (4%) had primary aldosteronism (PA), 39 (3%) had Cushing syndrome, 18 (1%) had PA and MACS, and 226 (15%) had incomplete work-up. Age, sex, tumor size, and tumor laterality, but not unenhanced computed tomography Hounsfield units (HU), were associated with hormonal subtypes. In a multivariable analysis, ≥1 cm growth was associated with younger age (odds ratio [OR] = 0.8 per 5-year increase, P = .0047) and longer imaging follow-up (OR = 1.2 per year, P < .0001). Adrenalectomy was performed in 355 (23%) patients, including 38% of MACS and 15% of NFA. Adrenalectomy for NFA and MACS was more common in younger patients (OR = 0.79 per 5-year increase, P = .002), larger initial tumor size (OR = 2.3 per 1 cm increase, P < .0001), ≥1 cm growth (OR = 15.3, P < .0001), and higher postdexamethasone cortisol (OR = 6.6 for >5 vs <1.8 µg/dL, P = .002). CONCLUSIONS: Age, sex, tumor size, and laterality were associated with ACA hormonal subtype and can guide diagnosis and management. Tumor growth was more common with younger age and longer follow-up. Unenhanced HU did not predict hormonal subtype or growth. Adrenalectomy for MACS and NFA was mainly performed in younger patients with larger tumor size, growth, and elevated postdexamethasone cortisol.

Oncocytic adrenal cortical adenoma: a benign lesion mimicking malignancy.

Adrenocortical tumours are rare in children and account for only 0.3%-0.4% of all neoplasms in childhood. They present with variable signs and symptoms, depending on the type of hormonal hypersecretion. The majority of the adrenocortical tumours in children are functional (90%) and malignant (88%). Here, we describe a functional plurihormonal oncocytic adrenal cortical adenoma in a young girl, that mimicked a malignant adrenal lesion, clinically as well as on imaging and biochemical features. This report bears the objective of being aware of the atypical biochemical as well as imaging characteristics of oncocytic adrenal tumours.

Multimodal integration of radiology and pathology signatures for distinguishing between aldosterone-producing adenomas and nonfunctional adrenal adenomas.

OBJECTIVE: To develop and validate a nomogram combining radiomics and pathology features to distinguish between aldosterone-producing adenomas (APAs) and nonfunctional adrenal adenomas (NF-AAs). METHODS: Consecutive patients diagnosed with adrenal adenomas via computed tomography (CT) or pathologic analysis between January 2011 and November 2022 were eligible for inclusion in this retrospective study. CT images and hematoxylin & eosin-stained slides were used for annotation and feature extraction. The selected radiomics and pathology features were used to develop a risk model using various machine learning models, and the area under the receiver operating characteristic curve (AUC) was determined to evaluate diagnostic performance. The predicted results from radiomics and pathology features were combined and visualized using a nomogram. RESULTS: A total of 211 patients (APAs, n = 59; NF-AAs, n = 152) were included in this study, with patients randomly divided into either the training set or the testing set at a ratio of 8:2. The ExtraTrees model yielded a sensitivity of 0.818, a specificity of 0.733, and an accuracy of 0.756 (AUC = 0.817; 95% confidence interval [CI]: 0.675-0.958) in the radiomics testing set and a sensitivity of 0.999, a specificity of 0.842, and an accuracy of 0.867 (AUC = 0.905, 95% CI: 0.792-1.000) in the pathology testing set. A nomogram combining radiomics and pathology features demonstrated a strong performance (AUC = 0.912; 95% CI: 0.807-1.000). CONCLUSION: A nomogram combining radiomics and pathology features demonstrated strong predictive accuracy and discrimination capability. This model may help clinicians to distinguish between APAs and NF-AAs.

A Comparison of Near-Infrared Autofluorescence Findings in Benign Versus Malignant Adrenal Tumors.

BACKGROUND: Many adrenal tumors are deemed radiologically indeterminate and surgically removed. Adrenal tissue, like parathyroid glands, exhibits near-infrared autofluorescence (NIRAF) properties. This study was designed to investigate the potential of NIRAF to differentiate benign versus malignant adrenal tumors. METHODS: Patients undergoing adrenalectomy between October 2021 and May 2023 were prospectively studied. Adrenalectomy specimens were inspected with NIRAF imaging. Specimen autofluorescence (AF) characteristics were recorded. Comparisons were made between different tumor types and a logistic regression model was constructed to differentiate benign versus malignant tumors. A receiver operating characteristic curve was used to identify an optimal AF threshold differentiating benign versus malignant tumors. RESULTS: A total of 108 adrenal specimens were examined: adrenocortical adenomas/other benign lesions (n = 72), pheochromocytomas (n = 18), adrenocortical neoplasms of uncertain behavior (n = 4), and malignant tumors (n = 14). A significant difference in normalized AF intensity was identified when comparing adrenocortical adenomas (3.08 times background) with pheochromocytomas (1.95, p = 0.001) and malignant tumors (1.11, p < 0.0001). The Area Under the Curve differentiating benign vs malignant tumors was 0.87, with an optimal normalized AF threshold at 1.93. CONCLUSIONS: Different adrenal pathologies exhibit diverse AF properties. These findings suggest a potential intraoperative utility of NIRAF in predicting benign versus malignant nature for radiologically indeterminate adrenal tumors.

Adrenocortical Adenoma Arising from Adrenohepatic Fusion: A Mimic of Hepatocellular Carcinoma-Case Report.

AIM: We present a case of adrenocortical adenoma originating from the adrenohepatic fusion (AHF) region, accompanied by advanced hepatosteatosis in the liver tissue, and discuss its distinction from hepatocellular carcinoma.  Case Experience: A 68-year-old male patient was admitted to the hospital following a fall from a height. He was referred to our hospital after an incidental discovery of a liver mass during an abdominal ultrasound examination. Subsequently, magnetic resonance imaging (MRI) imaging was conducted, followed by segmental liver resection with right adrenalectomy, and histological analysis of a biopsy from the lesion.  Results: Upon histologic examination, the case was determined to be an adrenocortical adenoma originating from the AHF.  Discussion: Adrenohepatic fusion (AHF) denotes the histological amalgamation of cells from the right adrenal cortex and right hepatic parenchyma. Only a limited number of cases of neoplasia originating from this region have been documented. These rare instances often present a diagnostic challenge, with preoperative imaging frequently misidentifying them as primary malignancies of either hepatic or adrenal origin, potentially leading to unnecessary extensive resections. The integration of immunohistochemical staining alongside clinical and radiological data proves helpful for accurately diagnosing this condition.  Conclusion: Awareness among clinicians, radiologists, and pathologists regarding the tumors that may arise from this region can mitigate the risk of performing extensive resections unnecessarily.

Adrenal cortical adenoma arising in the setting of renal-adrenal fusion: a case report and review of the literature.

BACKGROUND: Renal-adrenal fusion is a rare entity resulting from incomplete encapsulation of the adrenal gland and kidney. Only 18 cases have been reported in English literature to date. CASE PRESENTATION: Our patient is a 77-year-old African American female who presented with a systolic blood pressure of 200 mmHg. Computed tomography showed an enhancing 9 × 6 cm mass anterior and medial to the left kidney. The patient underwent a left adrenalectomy with partial nephrectomy. Gross and histologic examinations revealed an adrenal cortical adenoma and renal-adrenal fusion. CONCLUSION: Renal-adrenal fusion may pose a diagnostic challenge, particularly when there is a concurrent adrenal adenoma. It is important to be aware of this uncommon anomaly to avoid misdiagnosis and overtreatment.

Role of computed tomography in predicting adrenal adenomas with cortisol hypersecretion.

OBJECTIVES: To investigate performance of adrenal CT-derived multivariate prediction models in differentiating adenomas with cortisol hypersecretion from the other subtypes. METHODS: This retrospective study included 127 patients who underwent adrenal CT and had a surgically proven adrenal adenoma. Adenoma subtypes were defined according to biochemical test results: Group A, overt cortisol hypersecretion; Group B, mild cortisol hypersecretion; Group C, aldosterone hypersecretion; and Group D, non-function. Two independent readers analyzed size, attenuation, and washout properties of adenomas, and performed quantitative and qualitative analyses for assessing contralateral adrenal atrophy. Actual and internally validated areas under the curves (AUCs) of adrenal CT-derived multivariate prediction models for differentiating adenomas with cortisol hypersecretion from the other subtypes were assessed. RESULTS: In differentiating Group A from the other groups, the actual and internally validated AUCs of the prediction model were 0.856 (95% confidence interval [CI]: 0.786, 0.926) and 0.847 (95% CI: 0.695, 0.999) for Reader 1, respectively, and 0.901 (95% CI: 0.845, 0.956) and 0.897 (95% CI: 0.783, 1.000) for Reader 2, respectively. In differentiating Group B from groups C and D, the actual and internally validated AUCs of the prediction model were 0.777 (95% CI: 0.687, 0.866) and 0.760 (95% CI: 0.552, 0.969) for Reader 1, respectively, and 0.783 (95% CI: 0.690, 0.875) and 0.765 (95% CI: 0.553, 0.977) for Reader 2, respectively. CONCLUSION: Adrenal CT may be useful in differentiating adenomas with cortisol hypersecretion from the other subtypes. ADVANCES IN KNOWLEDGE: Adrenal CT may benefit in adrenal adenoma subtyping.

Feasibility of single-port laparoscopic partial adrenalectomy with selective adrenal venous sampling and high-resolution ultrasound for unilateral aldosterone-producing adenomas.

BACKGROUND: The surgical and endocrinological outcomes of single-port laparoscopic partial adrenalectomy for patients with aldosterone-producing adenomas are unknown. Precise diagnosis of intra-adrenal aldosterone activity and a precise surgical procedure may improve outcomes. In this study, we aimed to determine the surgical and endocrinological outcomes of single-port laparoscopic partial adrenalectomy with preoperative segmental selective adrenal venous sampling and intraoperative high-resolution laparoscopic ultrasound in patients with unilateral aldosterone-producing adenomas. We identified 53 patients with partial adrenalectomy and 29 patients with laparoscopic total adrenalectomy. Single-port surgery was performed for 37 and 19 patients, respectively. METHODS: A single-center, retrospective cohort study. All patients with unilateral aldosterone-producing adenomas diagnosed by selective adrenal venous sampling and treated surgically between January 2012 and February 2015 were included. Follow-up with biochemical and clinical assessments was set at 1 year after surgery for short-term outcomes and was performed every 3 months after surgery. RESULTS: We identified 53 patients with partial adrenalectomy and 29 patients with laparoscopic total adrenalectomy. Single-port surgery was performed for 37 and 19 patients, respectively. Single-port surgery was associated with shorter operative and laparoscopic times (odds ratio, 0.14; 95% confidence interval, 0.039-0.49; P = .002 and odds ratio, 0.13; 95% confidence interval, 0.032-0.57; P = .006, respectively). All single-port and multi-port partial adrenalectomy cases showed complete short-term (median 1 year) biochemical success, and 92.9% (26 of 28 patients) who underwent single-port partial adrenalectomy and 100% (13 of 13 patients) who underwent multi-port partial adrenalectomy showed complete long-term (median 5.5 years) biochemical success. No complications were observed with single-port adrenalectomy. CONCLUSION: Single-port partial adrenalectomy is feasible after selective adrenal venous sampling for unilateral aldosterone-producing adenomas, with shorter operative and laparoscopic times and a high rate of complete biochemical success.

Using CT radiomic features based on machine learning models to subtype adrenal adenoma.

BACKGROUND: Functioning and non-functioning adrenocortical adenoma are two subtypes of benign adrenal adenoma, and their differential diagnosis is crucial. Current diagnostic procedures use an invasive method, adrenal venous sampling, for endocrinologic assessment. METHODS: This study proposes establishing an accurate differential model for subtyping adrenal adenoma using computed tomography (CT) radiomic features and machine learning (ML) methods. Dataset 1 (289 patients with adrenal adenoma) was collected to develop the models, and Dataset 2 (54 patients) was utilized for external validation. Cuboids containing the lesion were cropped from the non-contrast, arterial, and venous phase CT images, and 1,967 features were extracted from each cuboid. Ten discriminative features were selected from each phase or the combined phases. Random forest, support vector machine, logistic regression (LR), Gradient Boosting Machine, and eXtreme Gradient Boosting were used to establish prediction models. RESULTS: The highest accuracies were 72.7%, 72.7%, and 76.1% in the arterial, venous, and non-contrast phases, respectively, when using radiomic features alone with the ML classifier of LR. When features from the three CT phases were combined, the accuracy of LR reached 83.0%. After adding clinical information, the area under the receiver operating characteristic curve increased for all the machine learning methods except for LR. In Dataset 2, the accuracy of LR was the highest, reaching 77.8%. CONCLUSION: The radiomic features of the lesion in three-phase CT images can potentially suggest the functioning or non-functioning nature of adrenal adenoma. The resulting radiomic models can be a non-invasive, low-cost, and rapid method of minimizing unnecessary testing in asymptomatic patients with incidentally discovered adrenal adenoma.

68Ga-DOTATATE PET/CT of ACTH-Independent Cushing Syndrome Due to Ectopic Adrenocortical Adenoma.

ABSTRACT: Adrenocorticotropic hormone-independent Cushing syndrome due to ectopic adrenocortical adenoma is a very rare entity. We herein present a case of a 57-year-old woman who was referred to our hospital with persistent Cushing syndrome after undergoing unnecessary laparoscopic left adrenalectomy. 68Ga-DOTATATE PET/CT revealed increased uptake in the nodule in the right hilum, which was histologically confirmed to be ectopic adrenocortical adenoma. Removal of the tumor was followed by the disappearance of clinical symptoms of Cushing syndrome. In this case, 68Ga-DOTATATE PET/CT contributed to the diagnosis of ectopic adrenocortical adenoma.

Dual Energy-Derived Metrics for Differentiating Adrenal Adenomas From Nonadenomas on Single-Phase Contrast-Enhanced CT.

BACKGROUND. Adrenal masses are often indeterminate on single-phase postcontrast CT. Dual-energy CT (DECT) with three-material decomposition algorithms may aid characterization. OBJECTIVE. The purpose of this study was to compare the diagnostic performance of metrics derived from portal venous phase DECT, including virtual noncontrast (VNC) attenuation, fat fraction, iodine density, and relative enhancement ratio, for characterizing adrenal masses. METHODS. This retrospective study included 128 patients (82 women, 46 men; mean age, 64.6 ± 12.7 [SD] years) who between January 2016 and December 2019 underwent portal venous phase abdominopelvic DECT that showed a total of 139 adrenal lesions with an available reference standard based on all imaging, clinical, and pathologic records (87 adenomas, 52 nonadenomas [48 metastases, two adrenal cortical carcinomas, one ganglioneuroma, one hematoma]). Two radiologists placed ROIs to determine the following characteristics of the masses: VNC attenuation, fat fraction, iodine density normalized to portal vein, and for masses with VNC greater than 10 HU, relative enhancement ratio (ratio of portal venous phase attenuation to VNC attenuation). Readers' mean measurements were used for ROC analyses, and clinically optimal thresholds were derived as thresholds yielding the highest sensitivity at 100% specificity. RESULTS. Adenomas and nonadenomas were significantly different (all p < .001) in VNC attenuation (mean ± SD, 18.5 ± 12.9 vs 34.1 ± 8.9 HU), fat fraction (mean ± SD, 24.3% ± 8.2% vs 14.2% ± 5.6%), normalized iodine density (mean ± SD, 0.34 ± 0.15 vs 0.17 ± 0.17), and relative enhancement ratio (mean ± SD, 186% ± 96% vs 58% ± 59%). AUCs for all metrics ranged from 0.81 through 0.91. The metric with highest sensitivity for adenoma at the clinically optimal threshold (i.e., 100% specificity) was fat fraction (threshold, ≥ 23.8%; sensitivity, 59% [95% CI, 48-69%]) followed by VNC attenuation (≤ 15.2 HU; sensitivity, 39% [95% CI, 29-50%]), relative enhancement ratio (≥ 214%; sensitivity, 37% [95% CI, 25-50%]), and normalized iodine density (≥ 0.90; sensitivity, 1% (95% CI, 0-60%]). VNC attenuation at the traditional true noncontrast attenuation threshold of 10 HU or lower had sensitivity of 28% (95% CI, 19-38%) and 100% specificity. Presence of fat fraction 23.8% or greater or relative enhancement ratio 214% or greater yielded sensitivity of 68% (95% CI, 57-77%) with 100% specificity. CONCLUSION. For adrenal lesions evaluated with single-phase DECT, fat fraction had higher sensitivity than VNC attenuation at both the clinically optimal threshold and the traditional threshold of 10 HU or lower. CLINICAL IMPACT. By helping to definitively diagnose adenomas, DECT-derived metrics can help avoid downstream imaging for incidental adrenal lesions.

Differentiating between adrenocortical carcinoma and lipid-poor cortical adenoma: A novel cross-sectional imaging-based score.

BACKGROUND: Discrimination between adrenocortical carcinoma and lipid-poor cortical adenoma preoperatively is frequently difficult as these two entities have overlapping imaging characteristics. Differentiation will allow for the selection of the most appropriate operative approach and may help prevent over-treatment. We aimed to identify imaging features that could preoperatively differentiate adrenocortical carcinoma from lipid-poor cortical adenoma and use them in a novel imaging-based score. METHODS: We conducted a retrospective analysis of patients with pathologically proven adrenocortical carcinoma and lipid-poor cortical adenoma who underwent resection in a single tertiary referral center between March 1998 and August 2020. The inclusion criteria were diameter >1 cm, attenuation >10 Hounsfield units on nonenhanced computed tomography, and histopathologic diagnosis. Patients with metastatic or locally advanced adrenocortical carcinoma adenoma (stages 3-4) were excluded. We developed a score using binary logistic multivariate regression model in 5-fold derivation (∼70%) cohorts with stepwise backward conditional regression as feature selection. Standardized mean regression weight was used as variable score points. RESULTS: We identified 232 adrenals resected across 211 patients. By comparing the imaging characteristics of adrenocortical carcinoma (n = 56) and lipid-poor cortical adenoma (n = 156), we revealed statistically significant differences between the groups in 9 parameters: size, attenuation, thin and thick rim enhancement patterns, heterogeneity, calcification, necrosis, fat infiltration, and lymph node prominence. The score mean performance was 100% sensitivity for the exclusion of adrenocortical carcinoma, 80% specificity (95% confidence interval, 68.3-91.5), 66% positive predictive value (95% confidence interval, 52.3-78.7), and 100% negative predictive value with area under the curve of 0.974. CONCLUSION: We defined and evaluated a novel 9-variable, imaging-based score. This score outperformed any single variable and could facilitate safe preoperative discrimination of adrenocortical carcinoma and lipid-poor cortical adenoma.

Differential diagnostic value of plain CT scan in adrenal adenoma and non-adenoma: A two-center control study of mean attenuation value, minimum attenuation value, and CT histogram.

Objectives: To investigate the value of mean attenuation value (AVmean), minimum attenuation value (AVmin), and CT histogram (CTH) for the differential diagnosis of adrenal adenoma and non-adenoma in two medical centers. Methods: The plain CT data of 403 cases of adrenal adenoma and 141 cases of non-adenoma in center A were retrospectively analyzed, and compared with data of 86 cases of adenoma and 71 cases of non-adenoma in center B. All cases were confirmed by pathology or clinical follow-up. The diagnostic efficacy of AVmean ≤ 10 Hounsfield units (HU), AVmin ≤ 0 HU, and CTH negative pixels ≥ 10% for adrenal adenoma, and AVmin and CTH for adenoma with AVmean > 10Hu were compared between the two medical centers. Results: In medical centers A and B, the AUC of AVmean for the differential diagnosis of adenoma and non-adenoma was 0.956 and 0.956, respectively, and the corresponding sensitivity, specificity, and accuracy were, 0.591 and 0.663, 1.000 and 1.000, 0.697, and 0.815, respectively, when the threshold was ≤ 10 HU. The AUC of AVmin was 0.941 and 0.958, respectively, and the corresponding sensitivity, specificity, and accuracy were 0.869 and 0.826, 0.986, and 0.972, 0.899, and 0.892, respectively, when the threshold was ≤ 0 HU. The AUC of CTH negative pixels was 0.948 and 0.952, respectively, and the corresponding sensitivity, specificity, and accuracy were 0.759 and 0.674, 1.000 and 1.000, 0.822, and 0.822, respectively, when the threshold was ≥ 10%. Among adenoma with AVmean >10 HU, the best threshold of AVmin in center A and center B were -0.250HU and 2.375HU, and the corresponding AUC, sensitivity and specificity were 0.858 and 0.846, 0.691 and 0.586, 0.986 and 0.958; the best threshold of CTH in center A and center B were 0.895% and 0.775%, and the corresponding AUC, sensitivity and specificity were 0.873 and 0.822, 0.818 and 0.724, 0.837 and 0.915. Conclusion: AVmean, AVmin, and CTH are all important parameters for differentiating adrenal adenoma from non-adenoma. Even for adenomas with AVmean > 10 HU, AVmin and CTH still had high diagnostic efficiency. The three parameters are complementary, assisting clinicians to develop personalized treatments.

Oncocytic adrenocortical tumour presenting as an incidentaloma: a diagnostic challenge.

Oncocytic adrenocortical neoplasms are a rare histopathological subtype of adrenal tumours which are usually benign and, if malignant, are less likely to metastasise. We report a case of a non-functioning oncocytic adrenocortical tumour, identified incidentally in a middle-aged woman. It was initially reported as a left-sided 3.5×3.4×5.6 cm adrenal adenoma. It however increased in size to 5.4×4.0×4.3 cm on follow-up scans. Subsequent review of the scans revealed an indeterminate lesion with a precontrast density of 30 Hounsfield units, an absolute washout of 42.6% and a relative washout of 28.6%. As a result, laparoscopic left adrenalectomy was performed. Histology confirmed oncocytic adrenocortical carcinoma when using the Lin-Weiss-Bisceglia system, though it was deemed benign when using the Helsinki scoring system. There has been no evidence of recurrence to date. This case highlights the potential pitfalls in the diagnosis of oncocytic neoplasms and the increased specificity of the Helsinki score in assessing metastatic potential.

Evaluation of the T2-weighted (T2W) adrenal MRI calculator to differentiate adrenal pheochromocytoma from lipid-poor adrenal adenoma.

OBJECTIVES: To evaluate the T2-weighted (T2W) MRI calculator to differentiate adrenal pheochromocytoma from lipid-poor adrenal adenoma. METHODS: Twenty-nine consecutive pheochromocytomas resected between 2010 and 2019 were compared to 23 consecutive lipid-poor adrenal adenomas. Three blinded radiologists (R1, R2, R3) subjectively evaluated T2W signal intensity and heterogeneity and extracted T2W signal intensity ratio (SIR) and entropy. These values were imputed into a quantitative and qualitative T2W adrenal MRI calculator (logistic regression model encompassing T2W SIR + entropy and subjective SI [relative to renal cortex] and heterogeneity) using a predefined threshold to differentiate metastases from adenoma and accuracy derived by a 2 × 2 table analysis. RESULTS: Subjectively, pheochromocytomas were brighter (p < 0.001) and more heterogeneous (p < 0.001) for all three radiologists. Inter-observer agreement was fair-to-moderate for T2W signal intensity (K = 0.37-0.46) and fair for heterogeneity (K = 0.24-0.32). Pheochromocytoma had higher T2W-SI-ratio (p < 0.001) and entropy (p < 0.001) for all three readers. The quantitative calculator differentiated pheochromocytoma from adenoma with high sensitivity, specificity, and accuracy (100% [95% confidence intervals 88-100%], 87% [66-97%], and 94% [86-100%] R1; 93% [77-99%], 96% [78-100%], and 94% [88-100%] R2; 97% [82-100%], 96% [78-100%], and 96% [91-100% R3]). The qualitative calculator was specific with lower sensitivity and overall accuracy (48% [29-68%], 100% [85-100%], and 74% [65-83%] R1; 45% [26-64%], 100% [85-100%], and 72% [63-82%] R2; 59% [39-77%], 100% [85-100%], and 79% [70-88% R3]). CONCLUSIONS: T2W signal intensity and heterogeneity differ, subjectively and quantitatively, in pheochromocytoma compared to adenoma. Use of a quantitative T2W adrenal calculator which combines T2W signal intensity ratio and entropy was highly accurate to diagnose pheochromocytoma outperforming subjective analysis. KEY POINTS: • Pheochromocytomas have higher T2-weighted signal intensity and are more heterogeneous compared to lipid-poor adrenal adenomas evaluated subjectively and quantitatively. • The quantitative T2-weighted adrenal MRI calculator, a logistic regression model combining T2-weighted signal intensity ratio and entropy, is highly accurate for diagnosis of pheochromocytoma. • The qualitative T2-weighed adrenal MRI calculator had high specificity but lower sensitivity and overall accuracy compared to quantitative assessment and agreement was only fair-to-moderate.

Inter-individual comparison of diagnostic accuracy of adrenal washout CT compared to chemical shift MRI plus the T2-weighted (T2W) adrenal MRI calculator in indeterminate adrenal masses: a retrospective non-inferiority study.

OBJECTIVE: To compare diagnostic accuracy of washout (WO)-CT to chemical shift (CS)-MRI + T2W adrenal MRI Calculator (T2W-Calculator) to diagnose adrenal adenoma in indeterminate adrenal masses. METHODS: This retrospective, cross-sectional, non-inferiority study evaluated 40 consecutive indeterminate adrenal masses; each with WO-CT and MRI. Two blinded radiologists independently evaluated in mixed order: pre-contrast attenuation (Hounsfield Units, HU) and absolute WO ([Peak.HU-Delay.HU]/[Peak.HU-Pre.HU] × 100%), Chemical Shift Signal Intensity (CS-SI) Index, T2W SI ratio, and Entropy (which were imputed into the T2W-Calculator). Diagnostic accuracy for adrenal adenoma was tabulated using 2 × 2 tables. True -positive diagnoses of adenoma were CT = Pre-HU < 10 or absolute WO ≥ 60%, MRI = SI index ≥ 16.5% or T2W-Calculator < 0.631. RESULTS: There were 73% (29/40) adenomas and 27% (11/40) other masses (5 pheochromocytoma, 3 solitary fibrous tumor, 1 metastasis, 1 cavernous hemangioma, and 1 adrenocortical carcinoma). Sensitivity, specificity, and accuracy for diagnosis of adenoma using CT-WO were 78% (95% confidence intervals [CI] 56-93%), 35% (14-62%), and 57% (42-71%) Reader 1 and 72% (53-87%), 46% (17-77%), and 59% (41-76%) Reader 2. Sensitivity, specificity, and accuracy for diagnosis of adenoma using MRI were 100% (88-100%), 64% (34-90%), and 82% (67-97%) Reader 1 and 86% (68-96%), 73% (39-94%), and 80% (64-95%) Reader 2. MRI had higher overall accuracy (p = 0.02 Reader 1, 0.05 Reader 2) compared to CT-WO. CONCLUSION: Chemical shift MRI combined with the T2W adrenal MRI calculator is not inferior to CT Washout for diagnosis of adrenal adenoma among indeterminate adrenal masses.