Benign prostatic hyperplasia: value of MR imaging for determining histologic type.

PURPOSE: To assess the value of magnetic resonance (MR) imaging for determining the histologic type of benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS: Unenhanced T1- and T2-weighted images and gadolinium-enhanced T1-weighted images were obtained in the transverse plane at 1.5 T in 33 patients with BPH. Hyperphasia was classified as stromal or nonstromal. Nonstromal hyperplasia was diagnosed if (a) the nodules in the inner gland had heterogeneous high signal intensity on T2-weighted images and peripheral enhancement on gadolinium-enhanced images, (b) a surgical capsule was present, or (c) the inner gland volume to total volume ratio was greater than 0.75.

RESULTS: A correct diagnosis was made with MR imaging in 23 of 24 patients with nonstromal hyperplasia and eight of nine with stromal hyperplasia (94% accuracy). In nonstromal hyperplasia, nodular lesions were seen in 20 patients and a surgical capsule was seen in 19. Eighteen patients had a transition zone ratio greater than 0.75.

CONCLUSION: MR imaging appears to be useful for choosing the type of pharmacotherapy performed because accurate histologic assessment is possible.