Dynamic MRI for imaging tumor microvasculature: Comparison of susceptibility and relaxivity techniques in pelvic tumors

Purpose To assess the reproducibility of intrinsic relaxivity and both relaxivity‐ and susceptibility‐based dynamic contrast enhanced (DCE) MRI in pelvic tumors; to correlate kinetic parameters obtained and to assess whether acute antivascular effects are seen in response to cisplatin‐ or taxane‐based chemotherapy. Materials and Methods T1‐weighted and T2*‐weighted DCE‐MRI and basal R2* measurements were performed on three consecutive days in women with gynecological tumors. The third scan was 21.0 (range 17.3–23.5) hours after the first cycle of chemotherapy. Kinetic parameter estimates were obtained and correlated between techniques. Test‐retest reproducibility and response to treatment were assessed. Results Relative blood volume (rBV) and relative blood flow (rBF) correlated strongly with transfer constant (Ktrans), kep, and the initial area under the gadopentetate dimeglumine (Gd‐DTPA) concentration‐time curve (IAUGC) (all P < 0.01). The group 95% confidence interval (CI) for change was –10.8 to +12.1%; ±5.1%; –9.5 to +10.5%; ±7.5%; for Ktrans, ve, kep, and IAUGC, respectively, and ±13.6%, ±2.4%, ±11.6%, and ±11.0%, for rBV, mean transit time (MTT), rBF, and R2*, respectively. There were no significant acute changes in kinetic parameter estimates in response to treatment on group analysis, apart from a small decrease in ve. Conclusion The results confirm the dominant influence of flow on Ktrans in untreated gynecological tumors. There is no evidence of an acute, large magnitude antivascular effect caused by cisplatin‐ or taxane‐based chemotherapy. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.