MR imaging characteristics of noncancerous lesions of the prostate

Abstract

Radical prostatectomy specimens from 53 men with clinical stage A or B prostate cancer were retrospectively reviewed and compared with correlative axial T2-weighted magnetic resonance (MR) images obtained just before surgery. Non-cancerous lesions were evaluated for signal intensity and location. Focal high-signal-intensity areas (n = 72) were present in 81% of patients. The 26% of lesions seen in the central gland all correlated with cystic atrophy. Of the 53 lesions seen in the peripheral prostate, 47 (89%) were cystic atrophy without associated cancer, four (7.5%) cystic atrophy with cancer, and two (3.8%) focal inflammation. Focal low-signal-intensity areas (n = 42) were present in 60% of patients. Of the 31% of lesions in the central prostate, one-fifth correlated with benign prostatic hyperplasia (BPH) and four-fifths with fibrous tissue. Of the 69% of peripheral lesions, 83% corresponded to fibrous tissue, 10% to BPH, and 7% to normal tissue. Mixed lesions (n = 42) were present in 64% of patients; 86% of these were located centrally and 14% peripherally. All mixed central lesions were BPH; the peripheral lesions were areas of combined cystic atrophy and fibrosis. BPH of low or mixed signal intensity can extend into the peripheral prostate and mimic cancer. High-intensity cystic atrophy associated with cancer can mimic normal tissue.

Diffusion-Weighted Imaging of Prostate Cancer

“…Because of the similarity in signal intensity between prostate cancer and other benign lesions such as benign prostatic hyperplasia on T2W imaging, however, conventional MR imaging has good sensitivity (78%-83%) but low specificity (50%-55%) in detecting and localizing prostate cancer. [4][5][6][7][8][9] Additional procedures, such as MR spectroscopy, have been applied to achieve a more specific diagnosis and localization of prostate cancer. 19,20 Combined MR imaging and spectroscopy indicated the presence of tumor with high sensitivity (95%) and high specificity (91%).…”

“…4 This finding is nonspecific, however, because other diseases such as prostatitis or hyperplasia can also cause low signal intensity on T2W imaging. [5][6][7][8] Moreover, detection of prostate cancer in the transition zone, which is present in up to 30% of all prostate cancer, is difficult because this zone is the site of the origin of benign prostatic hyperplasia, which can have a heterogeneous appearance. 9 Recently, diffusion-weighted (DW) imaging has been available for abdominal and pelvic lesions such as liver, 10,11 renal, 12 and ovarian tumors.…”

Dynamic TurboFLASH subtraction technique for contrast-enhanced MR imaging of the prostate: correlation with histopathologic results.

“…Reported data for detection of tu mors with MR imaging are, in gen eral, poor especially for central gland tumors (20,21). The sensitivity for lo calization of tumors with dynamic subtracted TurboFLASH imaging was consistently better than that with fast SE images.…”

Determination of the cutoff level of apparent diffusion coefficient values for detection of prostate cancer

“…5 However, other pathological conditions, including infl ammation, hyperplasia, fi brosis, and hemorrhage, can also show low signal intensity on T2WI. [6][7][8][9][10] Detection of a transition zone (TZ) cancer could be much more diffi cult because the TZ is a common site of origin of benign hyperplasia, whose signal intensity can be similar to that of cancer on T2WI. 11,12 Although dynamic contrastenhanced MRI can detect prostate cancer as an enhanced area, some overlap in the enhancement patterns between tumors and hyperplastic nodules has been reported.…”