BACKGROUND: Subtype-related various computed tomography (CT) features of renal cell carcinoma (RCC) are a confusing factor in differentiating angiomyolipoma with minimal fat (AMLmf) from RCC. To overcome RCC heterogeneity, a scoring system, which integrates multiple discrimitive parameters can be helpful for differentiating AMLmf from RCC. PURPOSE: To develop a MDCT-based scoring system for differentiating AMLmf from RCC. MATERIAL AND METHODS: In 407 patients with pathologically confirmed 48 AMLmfs and 359 RCCs (247 clear cell RCCs, 67 papillary RCCs, and 45 chromophobe RCCs), MDCT features (ratio of long-to-short diameter, enhancement characteristics, tumor attenuation on unenhanced scan, tumor margin, calcification), age, and sex were compared between AMLmf and RCCs. Based on logistic regression, a scoring system for diagnosing AMLmf over RCC was built, and its diagnostic accuracy was evaluated. RESULTS: Scores suggesting AMLmf, i.e. the logit function as used in logistic regression analysis, were calculated as follows: Score = e(6.16.A-0.003.B+1.20.C+0.97.D+2.13.E-0.05.F)/1+e(6.16.A-0.003.B+1.20.C+0.97.D+2.13.E-0.05.F), where A = ratio of long-to-short diameter, B = enhancement amount in early excretory phase, C = homogeneous enhancement, D = tumor attenuation on unenhanced scan, E = sex, and F = age. Area under receiver-operating characteristics curve of scoring system was 0.919. With a score of 0.204 or higher, the scoring system yielded greatest accuracy (90%, 368/407) for diagnosing AMLmf over RCC, which was greater than that of any single MDCT or clinical parameter (53-85%) (P < 0.05). With a score of 0.317 or higher, sensitivity and specificity were 68% (32/48) and 95% (340/359). CONCLUSION: MDCT-based scoring system can improve diagnostic performance of MDCT in differentiating AMLmf from RCC and help patients with AMLmf to avoid unnecessary surgery with high specificity.
BACKGROUND: Subtype-related various computed tomography (CT) features of renal cell carcinoma (RCC) are a confusing factor in differentiating angiomyolipoma with minimal fat (AMLmf) from RCC. To overcome RCC heterogeneity, a scoring system, which integrates multiple discrimitive parameters can be helpful for differentiating AMLmf from RCC. PURPOSE: To develop a MDCT-based scoring system for differentiating AMLmf from RCC. MATERIAL AND METHODS: In 407 patients with pathologically confirmed 48 AMLmfs and 359 RCCs (247 clear cell RCCs, 67 papillary RCCs, and 45 chromophobe RCCs), MDCT features (ratio of long-to-short diameter, enhancement characteristics, tumor attenuation on unenhanced scan, tumor margin, calcification), age, and sex were compared between AMLmf and RCCs. Based on logistic regression, a scoring system for diagnosing AMLmf over RCC was built, and its diagnostic accuracy was evaluated. RESULTS: Scores suggesting AMLmf, i.e. the logit function as used in logistic regression analysis, were calculated as follows: Score = e(6.16.A-0.003.B+1.20.C+0.97.D+2.13.E-0.05.F)/1+e(6.16.A-0.003.B+1.20.C+0.97.D+2.13.E-0.05.F), where A = ratio of long-to-short diameter, B = enhancement amount in early excretory phase, C = homogeneous enhancement, D = tumor attenuation on unenhanced scan, E = sex, and F = age. Area under receiver-operating characteristics curve of scoring system was 0.919. With a score of 0.204 or higher, the scoring system yielded greatest accuracy (90%, 368/407) for diagnosing AMLmf over RCC, which was greater than that of any single MDCT or clinical parameter (53-85%) (P < 0.05). With a score of 0.317 or higher, sensitivity and specificity were 68% (32/48) and 95% (340/359). CONCLUSION: MDCT-based scoring system can improve diagnostic performance of MDCT in differentiating AMLmf from RCC and help patients with AMLmf to avoid unnecessary surgery with high specificity.
Authors: Guenther Schneider; Thorsten Probst; Miles A Kirchin; Jonas Stroeder; Peter Fries; Arno Buecker Journal: Radiol Med Date: 2015-06-19 Impact factor: 3.469