Published in:
01-02-2021 | Magnetic Resonance Imaging | Pancreas
Optimal target b-value on computed diffusion-weighted magnetic resonance imaging for visualization of pancreatic ductal adenocarcinoma and focal autoimmune pancreatitis
Published in: Abdominal Radiology | Issue 2/2021
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Purpose
To compare computed diffusion-weighted imaging (cDWI) feasibility with that of directly acquired DWI for visualizing pancreatic ductal adenocarcinoma (PDAC) and focal autoimmune pancreatitis (AIP).
Methods
From April 2012 to January 2017, 135 patients with PDAC (n = 111) or focal AIP (n = 24) were retrospectively enrolled. They underwent DWI with b-values of 0, 500, and 1000 s/mm2. From DWI0 and DWI1000, we generated cDWIs with targeted b-values of 1500, 2000, and 3000 s/mm2. The lesions’ signal intensities, image quality, signal intensity ratio (SIR) of lesions and pancreatic parenchyma to spinal cord, and lesion-to-pancreatic parenchyma contrast ratio (CR) were compared among the five DWI protocols (DWI500, DWI1000, cDWI1500, cDWI2000, and cDWI3000). SIR was analyzed by receiver operating characteristic (ROC) analyses.
Results
DWI500, DWI1000, and cDWI1500 had higher image quality than cDWI2000 and cDWI3000 (P < 0.001). The incidence of clear hyperintense PDAC was highest on cDWI2000, followed by cDWI1500, and cDWI3000 (P < 0.001–0.002), while the incidence of clear hyperintense AIP was higher on DWI1000, cDWI1500, and cDWI2000 than on DWI500 and cDWI3000 (P = 0.001–0.022). SIRs decreased whereas CRs increased as the b-value increased, for both PDAC and AIP. The area under the ROC curve (AUC) of SIRlesion was significantly lower on cDWI1500 than on cDWI2000 and cDWI3000 (P < 0.001).
Conclusion
cDWI1500 or cDWI2000 generated from b-values of 0 and 1000 s/mm2 were the most effective for visualizing PDAC and focal AIP; however, the SIRlesion AUC was significantly lower on cDWI1500 than on cDWI2000 and cDWI3000.