Diagnostic usefulness of endorectal magnetic resonance imaging with dynamic contrast-enhancement in patients with localized prostate cancer: mapping studies with biopsy specimens.

Abstract

New diagnostic criteria for dynamic magnetic resonance (MR) imaging in prostate cancer are presented. The diagnostic usefulness of endorectal MR imaging with dynamic contrast-enhancement in localized prostate cancer and the validity of these criteria were evaluated. Eighteen untreated patients who were suspected of localized prostate cancer were included in the study. They received endorectal dynamic MR imaging before systematic sextant needle biopsy. First. a mapping study with the findings of MR images and histopathology of biopsy specimens was performed in eight patients out of 18 to compare the difference in T2-weighted images with the endorectal coil and the body coil in the same individuals. Second, another mapping study was performed in all 18 patients by analyzing the findings of endorectal dynamic MR images. For the diagnosis of prostate cancer in MR imaging, we offered diagnostic criteria from our experience in addition to those in plain T2-weighted images from the literature. The overall diagnostic rates of endorectal dynamic MR imaging were 88.9% in accuracy, 100% in sensitivity, and 81.8% in specificity. In the comparison of the endorectal and body coils in T2-weighted images in eight patients, there was no difference in the diagnostic rates except for one more histopathologic false positive portion in endorectal MR imaging. In the second mapping study in 18 patients, the diagnostic rates were 92.6% in accuracy, 88.9% in sensitivity and 93.3% in specificity. Endorectal dynamic imaging raised the diagnostic sensitivity from 77.8 to 88.9%. The data demonstrated the validity of this diagnostic criteria and the diagnostic usefulness of endorectal dynamic MR imaging in localized prostate cancer.