Apparent diffusion coefficient as a predictive biomarker of XXXX progression: value of fast and slow diffusion components.

@entity1 @entity263 @entity5
OBJECTIVE: The purpose of our study was to investigate whether fast and slow components of the apparent diffusion coefficient (ADC) from diffusion-weighted MR images could predict @entity263 progression in @entity1 managed by active surveillance. SUBJECTS AND METHODS: Eighty-one @entity1 managed by active surveillance underwent diffusion-weighted MRI in addition to T2-weighted MRI using an endorectal technique. ADCs from @entity5 regions of interest were calculated using all b values (ADC(all)), b = 0-300 s/mm(2) (ADC(fast)), and b = 300-800 s/mm(2) (ADC(slow)). These parameters and @entity5 volumes were compared in those upgraded at subsequent biopsy (n = 14) versus those histologically stable (n = 41) and in evaluable @entity1 who progressed to radical treatment (n = 16) versus those who did not (n = 64). Cox's regression was used to analyze the effect of parameter mean on time to treatment. RESULTS: ADC(all), ADC(fast), and ADC(slow) in @entity1 upgraded on repeat biopsy were significantly lower than those who were stable (1,070    110 vs 1,356    357   10(-6)mm(2)/s, p < 0.001; 1,283    188 vs 1,526    397   10(-6)mm(2)/s, p = 0.004; 843    74 vs 1,105    285   10(-6) mm(2)/s, p < 0.001, respectively). @entity5 volume was significantly higher in the upgraded group (0.86    0.9 vs 0.26    0.25 cm(3), p = 0.02). The lower ADC(slow) in @entity1 who subsequently progressed to radical treatment approached significance (922    256 vs 1,054    235   10(-6) mm(2)/s, p = 0.053; hazard ratio, 0.991 for time to treatment). @entity5 volume was significantly higher in the treated group (0.86    0.85 cm(3) vs 0.32    0.33 cm(3), p = 0.02). ADC(slow) and @entity5 volume were significant but independent predictors of upgrade on biopsy (p = 0.01 and 0.002, respectively). CONCLUSION: Both fast and slow diffusion components were significantly lower in @entity5 that were subsequently upgraded on histology. Both @entity5 volume and the true diffusion ADC(slow) were significant but independent predictors of histologic progression.
