Accurate Therapeutic Response Assessment of Pancreatic Ductal Adenocarcinoma Using Quantitative Dynamic Contrast-Enhanced Magnetic Resonance Imaging With a Point-of-Care Perfusion Phantom A Pilot Study

Objectives: The aim of this study was to test the feasibility of dynamic contrastenhanced magnetic resonance imaging (DCE-MRI) with concurrent perfusion phantom for monitoring therapeutic response in patients with pancreatic ductal adenocarcinoma (PDAC). Materials andMethods: Aprospective pilot study was conductedwith 8 patients (7 men and 1 woman) aged 46 to 78 years (mean age, 66 years). Participants had either locally advanced (n = 7) or metastatic (n = 1) PDAC, and had 2 DCE-MRI examinations: one before and one 8 +/- 1 weeks after starting first-line chemotherapy. A small triplicate perfusion phantom was imaged with each patient, serving as an internal reference for accurate quantitative image analysis. Tumor perfusion was measured with Ktrans using extended Tofts model before and after phantombased data correction. Results are presented as mean +/- SD and 95% confidence intervals (CIs). Statistical difference was evaluated with 1-way analysis of variance. Results: Tumor-size change of responding group (n = 4) was -12% +/- 4% at 8 weeks of therapy, while that of nonresponding group (n = 4) was 18% +/- 15% (P = 0.0100). Before phantom-based data correction, the Ktrans change of responding tumors was 69% +/- 23% (95% CI, 32% to 106%) at 8 weeks, whereas that of nonresponding tumors was -1% +/- 41% (95% CI, -65% to 64%) (P = 0.0247). After correction, the data variation in each group was significantly reduced; the Ktrans change of responding tumors was 73% +/- 6% (95% CI, 64% to 82%) compared with nonresponding tumors of -0% +/- 5% (95% CI, -7% to 8%) (P < 0.0001). Conclusions: Quantitative DCE-MRI measured the significant perfusion increase of PDAC tumors responding favorably to chemotherapy, with decreased variability after correction using a perfusion phantom.