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

Abstract

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 T 2*-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 K trans in untreated gynecological tumors. There is no evidence of an acute, large magnitude antivascular effect caused by cisplatin- or taxane-based chemotherapy. © 2007 Wiley-Liss, Inc.