Serena Pullini MD, Presenter: Nothing to Disclose

Shi-Li Chao DIPLPHYS, PhD, Abstract Co-Author: Nothing to Disclose

Julie Absil PhD, MS, Abstract Co-Author: Nothing to Disclose

Francesco Puleo, Abstract Co-Author: Nothing to Disclose

Celso Matos MD, Abstract Co-Author: Nothing to Disclose

Maria-Antonetta Bali, Abstract Co-Author: Nothing to Disclose

To measure the performance of Histogram-based Apparent Diffusion Coefficient (ADC) analysis in the evaluation of treatment response in pancreatic ductal adenocarcinomas (PDC).

12 patients with PDC underwent T2-weighted and Diffusion-weighted MR (DW-MR) imaging acquired with nine b values (0,10,20,30,40,50,150,300,1000 s/mm^2), performed on 1.5T, before and after therapy (mean 6 weeks) with Gemcitabine alone (n=5) or combined Gemcitabine+nab-Paclitaxel (n=7). For each PDC, baseline and after-treatment: 1) tumour longest diameter on T2-weighted images (RECIST criteria); 2) tumour volume on DW-MR images and 3) Histograms ADC (H-ADC) parameters (mean, median, 10th, 25th, 75th, and 90th centile) obtained from the entire tumour volume, were calculated. The therapeutic response was based on clinical and biological evaluation. Mann-Whitney test and Wilcoxon test were applied for comparison.

8/12 patients (66,6%) were responders. In the responder group, tumour diameter decreased more than 30% in only one patient (1/8), whereas DW-MR-based tumour volume reduction was greater than 30% in all responders (p<0.01). After treatment, in responders both mean and median H-ADC increased (p=0.015), while there was no significant difference in non-responder group. In the responder group, baseline 75th and 90th percentile H-ADC values were significantly lower than those of non-responder group (p=0.03 and p=0.04, respectively).

DWI-based tumour volume provides a significant marker of PDC response to chemotherapy and H-ADC parameters may be useful in evaluating and predicting tumour response.

DWI-based tumour volume and Histogram-based ADC analysis may be useful in evaluating and predicting chemotherapy response in advanced pancreatic ductal adenocarcinomas.

Pullini, S, Chao, S, Absil, J, Puleo, F, Matos, C, Bali, M, Assessment of Treatment Response in Pancreatic Ductal Adenocarcinomas: Value of Histogram-based Apparent Diffusion Coefficient analysis. Preliminary Results.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14008028.html