Application of R2 and Apparent Diffusion Coefficient in Estimating Tumor Grade and T Category of Bladder Cancer

• Published in: American journal of roentgenology (1976) Vol. 214; no. 2; pp. 383 - 389
• Main Authors: Wang, Yanchun, Shen, Yaqi, Hu, Xuemei, Li, Zhen, Feng, Cui, Hu, Daoyu, Kamel, Ihab R.
• Format: Journal Article
• Language: English
• Published: United States 01.02.2020
• Subjects: Adult; Aged; Aged, 80 and over; Diffusion Magnetic Resonance Imaging - methods; Female; Humans; Male; Middle Aged; Neoplasm Grading; Neoplasm Staging; Prospective Studies; Urinary Bladder Neoplasms - diagnostic imaging; Urinary Bladder Neoplasms - pathology; Urinary Bladder Neoplasms - surgery; T2-weighted imaging; MRI; bladder cancer; DWI
• ISSN: 0361-803X; 1546-3141; 1546-3141
• DOI: 10.2214/AJR.19.21668

The objective of our study was to compare the feasibility of R2* and apparent diffusion coefficient (ADC) for differentiating tumor grade and T category of bladder cancer. In this prospective study, 58 patients with pathologically confirmed bladder cancers underwent pretreatment T2*-weighted imaging and DWI on a 3-T MRI unit. The apparent transverse relaxation rate R2*, which is derived from T2*-weighted imaging, and ADC, which is derived from DWI, were calculated and compared between low- and high-grade bladder cancers as well as between non-muscle-invasive bladder cancers (NMIBCs) and muscle-invasive bladder cancers (MIBCs) using the Mann-Whitney test. The diagnostic performances of R2*, ADC, and the combination of R2* and ADC were evaluated through an ROC analysis. Significant differences were found in R2* (mean ± SD, 16.55 ± 5.54 vs 20.96 ± 7.75 s ; = 0.001) and ADC (1.62 ± 0.31 vs 1.33 ± 0.21 × 10 mm /s; < 0.001) between lowand high-grade bladder cancers. R2* was significantly higher (22.56 ± 8.41 vs 18.06 ± 6.46 s ; 0.008) and ADC was considerably lower (1.21 ± 0.18 vs 1.53 ± 0.27 × 10 mm /s; < 0.001) in MIBCs than in NMIBCs. The AUCs for differentiating low-from high-grade groups were 0.714 using R2* and 0.779 using ADC. AUCs for distinguishing between NMIBC and MIBC groups using R2* and ADC were 0.682 and 0.850, respectively. In addition to ADC, R2* can be used as a quantitative imaging biomarker to provide additional information for tumor characterization of bladder cancer.