Renal Cortical Tumors: Use of Multiphasic Contrast-enhanced MR Imaging to Differentiate Benign and Malignant Histologic Subtypes

• Published in: Radiology Vol. 264; no. 3; pp. 779 - 788
• Main Authors: VARGAS, Hebert Alberto, CHAIM, Joshua, LEFKOWITZ, Robert A, LAKHMAN, Yulia, JUNTING ZHENG, MOSKOWITZ, Chaya S, SOHN, Michael J, SCHWARTZ, Lawrence H, RUSSO, Paul, AKIN, Oguz
• Format: Journal Article
• Language: English
• Published: Oak Brook, IL Radiological Society of North America 01.09.2012; Radiological Society of North America, Inc
• Subjects: Adult; Aged; Aged, 80 and over; Biological and medical sciences; Contrast Media; Diagnosis, Differential; Female; Gadolinium DTPA; Humans; Image Interpretation, Computer-Assisted; Investigative techniques, diagnostic techniques (general aspects); Kidney Cortex - pathology; Kidney Neoplasms - pathology; Kidneys; Linear Models; Magnetic Resonance Imaging - methods; Male; Medical sciences; Middle Aged; Neoplasm Grading; Nephrology. Urinary tract diseases; Original Research; Retrospective Studies; Tumors of the urinary system; Kidney disease; Nuclear medicine; Urinary system disease; Kidney tumor; Radiology; Medical imagery; Histology; Malignant tumor; Nuclear magnetic resonance imaging; Cancer
• ISSN: 0033-8419; 1527-1315
• DOI: 10.1148/radiol.12110746

To investigate the use of quantitative multiphasic contrast material-enhanced magnetic resonance (MR) imaging in differentiating between common benign and malignant histologic subtypes of renal cortical tumors. The institutional review board waived informed consent and approved this retrospective HIPAA-compliant study of 138 patients who underwent preoperative contrast-enhanced MR imaging during the period of January 2004-December 2008. At surgery, 152 renal tumors were identified (77 clear cell, 22 papillary, 18 chromophobe, and 10 unclassified carcinomas; 16 oncocytomas; nine angiomyolipomas). Three readers independently identified and measured the most-enhanced area in each tumor and placed corresponding regions of interest in similar positions on images from the precontrast, corticomedullary, nephrographic, and excretory phases. The percentage change in signal intensity (%SI change) between precontrast imaging and each postcontrast phase was calculated. Interreader agreement was evaluated by using the overall concordance correlation coefficient (OCC). A linear mixed-effects model was used to estimate and compare the trajectories of the means of log %SI change across all phases between the six histologic subtypes. Interreader agreement was substantial to almost perfect (OCC, 0.77-0.88). The %SI change differed significantly between clear cell carcinomas and papillary and chromophobe carcinomas in all phases of enhancement (P < .0001-.0120). In addition, %SI change was significantly higher in angiomyolipomas than in clear cell carcinomas, but only in the corticomedullary phase (P = .0231). Enhancement did not differ significantly between clear cell carcinoma and oncocytoma in any phase (P = .2081-.6000). Quantitative multiphase contrast-enhanced MR imaging offers a widely available, reproducible method to characterize several histologic subtypes of renal cortical tumors, although it does not aid differentiation between clear cell carcinomas and oncocytomas.