WE-FG-206-09: Association of Prostate Volumes with Restricted Diffusion and Prostate Cancer Aggressiveness

Authors


Abstract

Purpose:

To create an automatic workflow for evaluation of thresholds of restricted diffusion, based on Apparent Diffusion Coefficient (ADC) values in multiparametric (mp)MRI of the prostate. To investigate the association of these volumes with biopsy Gleason Score (GS).

Methods:

Patients with prostate cancer, imaged on 3T Discovery MR750 (GE, Waukesha, WI) magnet were selected from departmental database based on the presence of mpMRI exam. All subsequent analyses were performed using Java plugins in MIM (MIM, Cleveland, Ohio). Prostate, peripheral zone (PZ) and urethra were contoured manually for each patient. The procedure defines three volumes on ADC in PZ, related to high (<T1 µm2/s), medium (<T2 µm2/s), and low risk (<T3 µm2/s), where T1<T2<T3. The thresholds for each patient were set 200 µm2/s apart, i.e. T2=T1+200 µm2/s and T3=T1+400 µm2/s. The thresholds were offset by 100 µm2/s for the transition zone (TZ). Pixels with ADC<400 µm2/s and within the urethra are excluded from the analysis. The correlations between (i) ADC volume sizes; and (ii) the fractions of the volumes from the prostate volume (ADC/Prostate) and GS were investigated with Spearman correlation.

Results:

mpMRIs from 139 the analysis. The correlations between (i) ADC volume sizes; and (ii) the fractions of the volumes from the prostate volume (ADC/Prostate) and GS were investigated with Spearman correlation.

Results:

mpMRIs from 139 selected patients with mpMRI acquired between May, 2012 and February, 2016, were analyzed. Six values for T1 were investigated starting from 750 to 950 µm2/s with step of 50 µm2/s. All correlations between ADC volumes and ADC/Prostate volumes and GS were significant. The following thresholds for PZ/TZ: 950/700, 1100/900 and 1200/1100 performed the best for high, mid and low risk. The correlation coefficients of of ADC high and ADC high/Prostate were 0.45 and 0.469 with p-values <<0.00001.

Conclusion:

To the best of our knowledge, this is the first report which associates volumes of low diffusion and GS.

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