caa a22 4500 605492352 CHVBK 20210128100514.0 cr unu---uuuuu 210128e20150801xx s 000 0 eng 10.1007/s00261-014-0307-6 doi (NATIONALLICENCE)springer-10.1007/s00261-014-0307-6 Histogram analysis for characterization of indeterminate adrenal nodules on noncontrast CT [Elektronische Daten] [Michael Lin, Lauren Chang-Sen, Jay Heiken, Thomas Pilgram, Kyongtae Bae] Objective: To determine the effectiveness of the CT histogram method to characterize indeterminate adrenal nodules above 10Hounsfield units (HU) on noncontrast CT. Materials and methods: Retrospective review of clinical CT data from January 2005 through 2008 identified 194 indeterminate adrenal nodules (>10HU on noncontrast CT) in 175 patients. 20 nodules in 18 patients were excluded due to large standard deviation (SD>30) of HU values. Of the remaining 174 nodules, 131 were classified as benign lipid-poor nodules based on size stability for ≥1year (104), in- and opposed-phase MRI (17), adrenal washout CT (3), or biopsy (7). 43 were classified as malignant by size increase over a short time (30), avid FDG uptake on PET/CT (15), or biopsy (5). Histogram analysis was performed by drawing a circular region of interest on all adrenal nodules. Mean attenuation, total number of pixels, number of negative pixels, and percentage of negative pixels were recorded for each nodule. Results: At the threshold value of >10% negative pixels, 59/131 benign nodules were correctly characterized, but 1/43 malignant nodules was falsely characterized as benign (sensitivity 45%, specificity 98%, positive predictive value 98%). With a slightly higher threshold value of >15% negative pixels, there were no false benign judgments. 36 nodules had more than 15% negative pixels, all of which were benign (sensitivity 27%, specificity 100%, positive predictive value 100%). In the subgroup of benign nodules measuring 11-20HU, 80% and 54% were identified with threshold values of >10% and >15% negative pixels, respectively. Conclusion: The CT histogram method with a threshold value of >10% negative pixels can identify many benign adrenal nodules with attenuation values >10HU on unenhanced CT with extremely high specificity. A threshold of >15% negative pixels can achieve 100% specificity. This method is highly robust provided very "noisy” CT examinations (SD>30) are eliminated. Springer Science+Business Media New York, 2014 CT nationallicence Histogram analysis nationallicence Adrenal nodules nationallicence Negative pixels nationallicence CT noise nationallicence Lin Michael Mallinckrodt Institute of Radiology, Washington University in St. Louis, 510 South Kingshighway, Box 8131, 63131, St. Louis, MO, USA aut Chang-Sen Lauren University of Pittsburgh Medical Center, Pittsburgh, PA, USA aut Heiken Jay Mallinckrodt Institute of Radiology, Washington University in St. Louis, 510 South Kingshighway, Box 8131, 63131, St. Louis, MO, USA aut Pilgram Thomas St. Louis, USA aut Bae Kyongtae University of Pittsburgh Medical Center, Pittsburgh, PA, USA aut Abdominal Imaging Springer US; http://www.springer-ny.com 40/6(2015-08-01), 1666-1674 0942-8925 40:6<1666 2015 40 261 https://doi.org/10.1007/s00261-014-0307-6 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 review-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00261-014-0307-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lin Michael Mallinckrodt Institute of Radiology, Washington University in St. Louis, 510 South Kingshighway, Box 8131, 63131, St. Louis, MO, USA aut NATIONALLICENCE 700 1- Chang-Sen Lauren University of Pittsburgh Medical Center, Pittsburgh, PA, USA aut NATIONALLICENCE 700 1- Heiken Jay Mallinckrodt Institute of Radiology, Washington University in St. Louis, 510 South Kingshighway, Box 8131, 63131, St. Louis, MO, USA aut NATIONALLICENCE 700 1- Pilgram Thomas St. Louis, USA aut NATIONALLICENCE 700 1- Bae Kyongtae University of Pittsburgh Medical Center, Pittsburgh, PA, USA aut NATIONALLICENCE 773 0- Abdominal Imaging Springer US; http://www.springer-ny.com 40/6(2015-08-01), 1666-1674 0942-8925 40:6<1666 2015 40 261