MR-guided biopsy of the prostate: an overview of techniques and a systematic review.

CONTEXT: Systematic transrectal ultrasound-guided biopsy (TRUSBx) is the gold standard for detecting prostate cancer. This systematic approach is characterized by low sensitivity (39-52%) and high specificity (81-82%). Magnetic resonance (MR)-guided biopsy techniques are becoming more and more available, but there is no current consensus on the optimal technique. OBJECTIVE: This review presents an overview of MR-guided biopsy techniques for prostate cancer detection. EVIDENCE ACQUISITION: Current literature was reviewed regarding MR-guided biopsy for prostate cancer detection. A literature search was performed using the commercially available MedLine online search engine. Combinations of the following search and Medical Subject Headings terms were applied to retrieve relevant articles: "magnetic resonance," "prostatic neoplasms," and "biopsy." Review articles and studies describing techniques other than MR-guided biopsy were excluded. EVIDENCE SYNTHESIS: Biopsy of the prostate is an essential procedure for determining optimal treatment. Systematic TRUSBx is the gold standard, but it fails to detect numerous tumors. Diagnostic MR imaging provides more accurate selection of regions in which tumors are suspected. Using these diagnostic images during an MR-directed biopsy procedure improves quality of the biopsy. In open MR scanners, the prebiopsy images often must be registered to the real-time biopsy images because open MR scanners do not provide optimal tissue contrast; thus, the patient must first be examined in a closed MR scanner and then biopsied in an open scanner. The advantage of open MR over closed MR is that the physician has easy patient access. With special equipment, prostate MR-guided biopsy is also possible in a closed system. Closed MR scanners can be used for the prebiopsy scan as well as for the biopsy procedure. CONCLUSIONS: The combination of a diagnostic MR examination and MR-guided biopsy is a promising tool and may be used in patients with previous negative TRUSBx