INTRODUCTIONCharacterizing adrenal lesions in patients with a known primary malignancy has a vital role in treatment and prognostication. Approximately 40-57% of adrenal incidentalomas are benign in these patients. 1 The prevalence of adrenal metastases in patients with known primary malignancy ranges between 32% and 73% in different series.2 CT, MRI and FDG PET are widely used to characterize adrenal lesions.In a retrospective study by Gufler et al, the combined morphologic criteria with the density measurements on NECT, found a high accuracy in differentiating adrenal adenomas from metastases in patients with a known malignancy.3 They proposed a scoring system based on density, contour, homogeneity and size.This study evaluates the sensitivity and specificity of this NECT scoring system and comparing it with that of 18F FDG PET. ABSTRACTBackground: Characterizing adrenal lesions in patients with a known primary malignancy has a vital role in treatment and prognostication. A study by Gufler et al proposed a scoring system based on density, contour, homogeneity and size and found a high accuracy in differentiating adrenal adenomas from metastasis in patients with a known malignancy. This study evaluates the sensitivity and specificity of this NECT scoring system and comparing it with that of 18F FDG PET. Methods: The study was conducted on patients with diagnosed malignancies with adrenal mass, referred for 18F-FDG PET-CT scanning as a part of work up or follows up between October 2014 and March 2016. Whole-body CT and PET images were obtained using standard protocol. NECT scoring and quantitative analysis of FDG uptake in the adrenal lesions (SUVavg analysis) is done separately. Results: Of the 50 patients studied, 33 patients had benign adrenal lesions and the rest had metastatic lesions. Most common site of primary was lung. NECT score yielded a sensitivity of 88.2%, specificity of 100% and positive predictive value of 100%. SUVavg analysis yielded a 100% sensitivity, specificity and positive predictive value. Comparison of the predictive power of the two tests showed a z score of 2.5 and p value of 0.0124. Conclusions: 18-FDG PET can be considered as a gold standard for differentiating between metastasis and benign lesions of adrenal glands in patients with known primary. NECT has a comparable specificity as that of FDG PET, however with lower sensitivity.

Background:Presently, computed tomography (CT) is the most important source of medical radiation exposure. CT radiation doses vary considerably across institutions depending on the protocol and make of equipment. India does not yet have national or region-specific CT diagnostic reference levels.Aim:To evaluate radiation doses of consecutive multidetector CT (MDCT) examinations based on anatomic region, performed in 1 month, collected simultaneously from seven tertiary care hospitals in Kerala.Settings and Design:Descriptive study.Materials and Methods:We collected the CT radiation dose data of examinations from the seven collaborating tertiary care hospitals in Kerala, performed with MDCT scanners of five different makes. The data included anatomic region, number of phases, CT dose index (CTDIvol), dose-length product (DLP), and effective dose (ED) of each examinations and patient demographic data.Statistical Analysis:We calculated the 25th, 50th, and 75th percentiles of the CTDIvol, DLP, and ED according to anatomic region. We made descriptive comparisons of these results with corresponding data from other countries.Results:Of 3553 patients, head was the most frequently performed examination (60%), followed by abdomen (19%). For single-phase head examinations, 75th percentile of CTDIvol was 68.1 mGy, DLP 1120 mGy-cm, and ED 2.1 mSv. The 75th percentiles of CTDIvol, DLP, and ED for single-phase abdomen examinations were 10.6, 509.3, and 7.7, and multiphase examinations were 14.6, 2666.9, and 40.8; single-phase chest examinations were 23.4, 916.7, and 13.38, and multiphase examinations were 19.9, 1737.6, and 25.36; single-phase neck were 24.9, 733.6, and 3.814, and multiphase neck were 24.9, 2076, and 10.79, respectively.Conclusion:This summary CT radiation dose data of most frequently performed anatomical regions could provide a starting point for institutional analysis of CT radiation doses, which in turn leads to meaningful optimization of CT.