AIM: To investigate the feasibility of T2* relaxation time for distinguishing benign from malignant regions,as well as tumour aggressiveness,within the peripheral zone(PZ)of the prostate in comparison with diffusion-weighted imaging(DWI).MATERIALS AND METHODS: Fifty-eight patients with prostate cancer underwent 3T magnetic resonance imaging using multiecho T2* and DWI(maximum b-value,2000 s/mm2).Parametric maps were obtained for apparent diffusion coefficient(ADC)and T2* values.Two radiologists reviewed these maps and measured ADC and T2* values in sextants positive for cancer at biopsy.Data were analysed using mixed-model analysis of variance and receiver operating characteristic curves.RESULTS: Ninety-three sextants exhibited a Gleason score of 6; 59 exhibited a Gleason score of 7 or 8.The T2* value was significantly lower in cancerous sextants than in the benign PZ(48.69t0.60 versus 74.14t0.56,p<0.001),as well as in cancerous sextants with higher rather than lower Gleason scores(43.18t0.89 versus 52.18t0.55,p<0.001).The T2* value showed significantly greater specificity for differentiating cancerous sextants from benign PZ than ADC(93.1%versus 89.7%,p<0.001),with equal sensitivity(82.8%versus 81%,p>0.05).The T2* value exhibited significantly greater sensitivity and specificity for differentiating sextants with low-and high-grade cancer than ADC(79.6%versus 64.5%and 81.4%versus 72.9%,respectively; p<0.05).The T2* value had a significantly greater area under the receiver operating characteristic curve for differentiating sextants with low-and high-grade cancer than ADC(0.77 versus 0.71,p<0.01).CONCLUSION: Preliminary findings suggest that the T2* relaxation time has increased diagnostic value compared with DWI in prostate PZ cancer assessment.