Presentation Quantitative analysis of circulatory function for prostate tumors using reference tissue model in DCE-MRI studies

Youko, Ikoma  ,  Obata, Takayuki  ,  Tachibana, Yasuhiko  ,  Omatsu, Tokuhiko  ,  Kishimoto, Riwa  ,  Tsuji, Hiroshi

In dynamic contrast-enhanced MRI (DCE-MRI) studies, a time-concentration curve of injected contrast agent is obtained from dynamically acquired T1-weighted images, and circulatory function around tumors is evaluated quantitatively by compartmental analysis with an arterial input function (AIF). However, it is difficult to obtain AIF individually, and AIF errors deteriorate the reliability of quantitative outcomes. In this study, we developed a quantitative analysis method using reference tissue, and applied it to DCE-MRI of prostate tumors. The reference tissue model, providing the ratio of transfer rate constants between the target and reference regions without AIF, was derived from a conventional one-tissue compartment model. In the DCE-MRI images of patients with prostate tumors, the model parameters in normal parts (transitional zone and peripheral zone) and tumor parts were estimated by the reference tissue model using the gluteus muscle as reference region. The differences between normal and tumor parts were evaluated using paired t-test with 0.05 as significance level, and were compared with those by the conventional method with AIF. The reference tissue model showed higher efflux rate constants in the tumors compared with normal parts, and the ability to discriminate between normal and tumor parts was better than that of the conventional method. The proposed method can provide reliable parameters related to circulatory function by a simple analysis, and it should be useful for the diagnosis of prostate tumors.

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