Purpose: Information regarding prostate blood flow as determined by positron emission tomography (PET) with (H2O)-O-15 may provide useful information about tumor diagnosis; however, PET requires a cyclotron for the production of an extremely short half-life (2 minutes) tracer. Therefore, the aim of this study was to propose a complementary index for blood flow as determined by MRI to validate the results and compare them with PET, especially for prostate tissue.
Methods: Six consecutive patients with prostate disease were studied. The two semiquantitative indices for tumor blood flow were calculated from the time-concentration curve measured from double-echo MR images. The theory of nondiffusible tracers by means of indicator dilution theory was applied to MR data. The relative regional blood flow (rrBF) was calculated as the ratio of the relative regional blood volume to relative regional mean transit time. Another proposed index was the maximum height of the time-concentration curve. PET studies Were also performed. and absolute blood flow values were calculated for each subject. These indices calculated from different modalities were then compared.
Results: A significant correlation was found between the rrBF and the absolute blood flow as determined by PET (r(2) = 0.69, p < 0.005). A significant correlation was also found between the maximum height of the time-concentration curve and the absolute blood flow (r(2) = 0.85, p < 0.0001).
Conclusions: The semiquantitative tumor blood flow indices measured with MRI have a good correlation with the corresponding measurements by PET therefore, these indices may provide useful information about tumor diagnosis in clinical settings.