Poster abstracts

Poster number 38 submitted by Huyen Nguyen

Diagnostic Value of Apparent Diffusion Coefficient in bladder cancer diagnosis

Huyen Nguyen (Wright Center of Innovation in Biomedical Imaging, Department of Radiology, The Ohio State University), Zarine Shah (Wright Center of Innovation in Biomedical Imaging, Department of Radiology, The Ohio State University), Guang Jia (Wright Center of Innovation in Biomedical Imaging, Department of Radiology, The Ohio State University), Kamal Pohar (Department of Urology, The Ohio State University), Amir Mortazavi (Department of Internal Medicine, The Ohio State University), Michael Knopp (Wright Center of Innovation in Biomedical Imaging, Department of Radiology, The Ohio State University)

Abstract:
20 patients with pathologic confirmation of bladder cancer were included in this prospective study. All patients had a baseline MRI on a 3T MRI system (Achieva, Philips Healthcare) using a multi-channel phased-array surface coil. 13 patients underwent neoadjuvant chemotherapy and had additional 1 or 2 post-chemotherapy MRI scans before their radical cystectomy. DWI data was processed on IDL (ITT)-based software to acquire ADC maps. On ADC maps, regions of interest (ROIs) were drawn to cover the whole tumor to get its tumor ADC. Tumor ADCs were correlated with pathologically confirmed T-stages. The change of tumor ADC values in the 13 patients after chemotherapy was correlated with the tumor chemotherapeutic responsiveness. Pathology diagnosed 3 patients with T1 or lower stage, 6 with T2 stage, 7 with T3 stage, and 4 with T4 stage. Average tumor ADCs of T1, T2, T3, and T4 stages were respectively 2.7±0.1(•10-3) (mm2/s), 2.3±0.2 (•10-3)(mm2/s), 2.0±0.3 (•10-3)(mm2/s), and 1.9±0.2(•10-3)(mm2/s). Statistical analysis of ADC showed that there were significant differences between ADC of stage T1 or lower and that of higher stages T2 (P<0.05), T3 (P<0.05), and T4 (P<0.01). In 9 out of 13 chemotherapy-treated patients, tumors were responsive to the treatment and shrank significantly in size. The other 4 patients represented a tumor progression or no shrink in tumor size. Analysis of tumor ADC change after chemotherapy revealed that ADC of responsive tumors significantly (P≤0.05) increased while that of nonresponsive tumors stayed unchanged or decreased. The findings of this Phase I study suggest that the quantitative analysis of ADC may guide in determining whether a bladder tumor is in an organ-confined (T1 or lower) or nonorgan-confined (T2 or higher) stage. Concurrently, the change of ADC can provide valuable information on tumor responsiveness to enable the accurate assessment of biologic effects of chemotherapy on bladder cancer.

References:
Yoshida S et al. Urology 2010; 75:387-391.
Kobayashi et al. Eur Radiol 2011; 21:2178-2186

Keywords: Diffusion Weighted MRI, Apparent Diffusion Coefficient, Chemotherapeutic Response