Combined magnetic resonance imaging and magnetic resonance spectroscopy imaging in the diagnosis of prostate cancer: a systematic review and meta-analysis.

CONTEXT Magnetic resonance imaging (MRI) combined with magnetic resonance spectroscopy imaging (MRSI) emerged as a promising test in the diagnosis of prostate cancer and showed encouraging results. OBJECTIVE The aim of this systematic review is to meta-analyse the diagnostic accuracy of combined MRI/MRSI in prostate cancer and to explore risk profiles with highest benefit. EVIDENCE ACQUISITION The authors searched the MEDLINE and EMBASE databases and the Cochrane Library, and the authors screened reference lists and contacted experts. There were no language restrictions. The last search was performed in August 2008. EVIDENCE SYNTHESIS We identified 31 test-accuracy studies (1765 patients); 16 studies (17 populations) with a total of 581 patients were suitable for meta-analysis. Nine combined MRI/MRSI studies (10 populations) examining men with pathologically confirmed prostate cancer (297 patients; 1518 specimens) had a pooled sensitivity and specificity on prostate subpart level of 68% (95% CI, 56-78%) and 85% (95% CI, 78-90%), respectively. Compared with patients at high risk for clinically relevant cancer (six studies), sensitivity was lower in low-risk patients (four studies) (58% [46-69%] vs 74% [58-85%]; p>0.05) but higher for specificity (91% [86-94%] vs 78% [70-84%]; p<0.01). Seven studies examining patients with suspected prostate cancer at combined MRI/MRSI (284 patients) had an overall pooled sensitivity and specificity on patients level of 82% (59-94%) and 88% (80-95%). In the low-risk group (five studies) these values were 75% (39-93%) and 91% (77-97%), respectively. CONCLUSIONS A limited number of small studies suggest that MRI combined with MRSI could be a rule-in test for low-risk patients. This finding needs further confirmation in larger studies and cost-effectiveness needs to be established.