title: Reproducibility of Dynamic Contrast-Enhanced MRI in Renal Cell Carcinoma: A Prospective Analysis on Intra- and Interobserver and Scan-Rescan Performance of Pharmacokinetic Parameters.
abstract: The objective of this study was to investigate the intra- and interobserver as well as scan-rescan reproducibility of quantitative parameters of renal cell carcinomas (RCCs) with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). A total of 21 patients with clear cell RCCs (17 men, 4 woman; age 37-69 years, mean age 54.6 years, mean size, 5.0 ± 2.2 cm) were prospectively recruited from September 2012 to November 2012. Patients underwent paired DCE-MRI studies on a 3.0 T MR system with an interval of 48 to 72 hours. The extended-Tofts model and population-based arterial input function were used to calculate kinetic parameters. Three observers defined the 2-dimensional whole-tumor region of interest at the slice with the maximum diameter of the RCC. Intraobserver and scan-rescan differences were assessed using paired t tests, whereas interobserver differences using two-way analysis of variance. Intra- and interobserver reproducibility and scan-rescan reproducibility were evaluated using within-subject coefficient of variation (wCoV) and intraclass correlation coefficient (ICC). There were no significant intra-, interobserver, or scan-rescan differences in parameters (all P > 0.05). All ICCs for intra- and interobserver agreements were >0.75 (P < 0.05), whereas the scan-rescan agreement was moderate to good; V(e) (0.764, 95% confidence interval [CI]: 0.378-0.925) and K(ep) (0.906, 95% CI: 0.710-0.972) had higher ICC than K(trans) (0.686; 95% CI: 0.212-0.898) and V(p) (0.657; 95% CI: 0.164-0.888). In intra- and interobserver variability analyses, all parameters except V(p) had low wCoV values. K(trans) and V(e) had slightly lower intraobserver wCoV (1.2% and 0.9%) compared with K(ep) (3.7%), whereas all 3 of these parameters had similar interobserver wCoV values (2.5%, 3.1%, and 2.9%, respectively). Regarding scan-rescan variability, K(trans) and K(ep) showed slightly higher variation (15.6% and 15.4%) than V(e) (10.1%). V(p) had the largest wCoV in all variability analyses (all >30%). DCE-MRI demonstrated good intra- and interobserver reproducibility and moderate to good scan-rescan performance in the assessment of RCC using K(trans), K(ep), and V(e) as parameters under noncontinuous scanning mode. V(p) showed poor reproducibility, and thus may not be suitable for this scanning protocol.
authors.affiliation: From the Department of Radiology (HW, HY, LL, LM), Chinese PLA General Hospital, Beijing, China; Advanced Application (ZS), GE Healthcare, Beijing, China; Advanced Application (XX), GE Healthcare, Shanghai, China; Department of Radiology (ZS), Zhangjiakou First Hospital, Zhangjiakou City, Hebei Province, China; Medical Imaging Center (FD), Jiayuguan Jiugang Hospital, Jiayuguan City, Gansu Province, China; Department of Radiology (YS), General Hospital of Pingdingshan Coal Group, Pingdingshan City, Henan Province, China; and Lincoln School of Computer Science (TL), University of Lincon, Lincon, UK.
authors.forename: Haiyi
authors.initials: H
authors.lastname: Wang
authors.forename: Zihua
authors.initials: Z
authors.lastname: Su
authors.forename: Huiyi
authors.initials: H
authors.lastname: Ye
authors.forename: Xiao
authors.initials: X
authors.lastname: Xu
authors.forename: Zhipeng
authors.initials: Z
authors.lastname: Sun
authors.forename: Lu
authors.initials: L
authors.lastname: Li
authors.forename: Feixue
authors.initials: F
authors.lastname: Duan
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Song
authors.forename: Tryphon
authors.initials: T
authors.lastname: Lambrou
authors.forename: Lin
authors.initials: L
authors.lastname: Ma
mesh_terms: D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000175:diagnosis*; D003287:Contrast Media / Q000493:pharmacokinetics*; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA