Functional characterization of prostate cancer by integrated magnetic resonance imaging and oxygenation changes during carbogen breathing

Objective: The objective of this study was to evaluate the changes in oxygenation of prostate cancer induced by carbogen breathing using blood oxygen level-dependent (BOLD) magnetic resonance image (MRI) with an endorectal coil (eMRI). Materials and Methods: In 32 patients with biopsy-proven prostate cancer, endorectal MRI was performed at 1.5 Testa using the BOLD method. Images were acquired during 4 X 4-minute episodes alternating between room air and carbogen (95% O-2/5% CO,) breathing. In each episode, 40 images were acquired (T2*-weighted EPI sequence, 12-14 slices, 3-mm thickness). All patients underwent radical prostatectorry; BOLD-MRI findings were correlated with the histopathologic results. Results: BOLD-MRI could be evaluated in 29 patients, and revealed heterogeneous signal changes of normal prostate and cancer tissue similar to the heterogeneity of prostate tissue in anatomic/pathologic preparation. A significant signal intensity increase (P = 0.004) was found in normal central gland and peripheral zone during carbogen breathing. Signal enhancement in carcinoma was significantly lower (P = 0.004) compared with the contralateral normal side. Conclusion: Intrinsic blood-tissue contrast-functional MRI during carbogen breathing may help detect and characterize prostate carcinoma from normal tissue, particularly in small I-sided carcinomas. This may be useful for identifying candidates for radiotherapy and monitoring noninvasive therapeutic approaches.