Dr(hc)
Purpose:To prospectively evaluate diagnostic performance of T2-weighted magnetic resonance (MR) imaging and MR spectroscopic imaging in detecting lesions stratified by pathologic volume and Gleason score in men with clinically determined low-risk prostate cancer.
Materials and Methods:The institutional review board approved this prospective, HIPAA-compliant study. Written informed consent was obtained from 183 men with clinically low-risk prostate cancer (cT1-cT2a, Gleason score 6 at biopsy, prostatespecific antigen [PSA] level , 10 ng/mL [10 mg/L]) undergoing MR imaging before prostatectomy. By using a scale of 1-5 (score 1, definitely no tumor; score 5, definitely tumor), two radiologists independently scored likelihood of tumor per sextant on T2-weighted images. Two spectroscopists jointly recorded locations of lesions with metabolic features consistent with tumor on MR spectroscopic images. Whole-mount step-section histopathologic analysis constituted the reference standard. Diagnostic performance at sextant level (T2-weighted imaging) and detection sensitivities (T2-weighted imaging and MR spectroscopic imaging) for lesions of 0.5 cm 3 or larger were calculated.
Results:For T2-weighted imaging, areas under the receiver operating characteristic curves for sextant-level detection were 0.77 (reader 1) and 0.82 (reader 2). For lesions of 0.5 cm 3 and ,1 cm 3 , sensitivities were significantly lower when the lesion Gleason score was 6 (0.
Conclusion:In men with clinically low-risk prostate cancer, detection of lesions of ,1 cm 3 with T2-weighted imaging is significantly dependent on lesion Gleason score; detection of lesions of 1 cm 3 is significantly better than detection of smaller lesions and is not affected by lesion Gleason score. The role of MR spectroscopic imaging alone in this population is limited.q RSNA, 20121 From the Departments of Radiology (H