Research articleComputed diffusion-weighted MR imaging for visualization of pancreatic adenocarcinoma: Comparison with acquired diffusion-weighted imaging

- DWI has been used for diagnosing pancreatic adenocarcinoma.
- DWI often fails to delineate pancreatic adenocarcinomas.
- DWI with a higher b-value can improve tumour delineation.
- Computed DWI can extrapolate higher b-value images from lower b-value images.
- Computed DWI at a b-value of 1500 s/mm2 is as useful as directly acquired DWI.

ObjectiveTo assess the feasibility of computed diffusion-weighted imaging (cDWI) in comparison with directly acquired DWI for visualizing pancreatic adenocarcinomas.Materials and methodsPatients with pancreatic adenocarcinoma underwent DWI at b-values of 0, 1000 (DWI1000), 1500 (DWI1500) and 2000 (DWI2000) s/mm2. From DWIs at b-values of 0 and 1000 s/mm2, we generated cDWIs at b-values of 1500 (cDWI1500) and 2000 (cDWI2000) s/mm2. DWI findings of pancreatic adenocarcinomas (clear hyperintensity; hyperintensity with an unclear distal border; and isointensity), the image quality and the tumor to pancreas contrast ratio (CR) were compared between directly acquired DWI and cDWI.ResultsAmong the 63 included patients, clear hyperintense tumors were seen in 35 on DWI1000, 50 on DWI1500, 50 on cDWI1500, 53 on DWI2000 and 44 on cDWI2000. Incidence of clear hyperintense tumors was significantly higher on cDWI1500 than on DWI1000 (P = 0.013). There was no significant difference in the incidence of clear hyperintense tumors between DWI1500 and cDWI1500 (P > 0.999), but a lower incidence was seen on cDWI2000 than on DWI2000 (P = 0.028). Image quality was lower on cDWI than on DWI at b-values of 1500 (P = 0.002) and 2000 s/mm2 (P < 0.001). The tumor to distal pancreas CR was significantly higher on cDWI2000 than on cDWI1500 (P < 0.001), and on cDWI1500 than on DWI1000 (P < 0.001). The cDWI showed a significantly higher tumor to distal pancreas CR than DWI at b-values of 1500 (P = 0.004) and 2000 s/mm2 (P < 0.001).ConclusionscDWI1500 generated from b-values of 0 and 1000 s/mm2 should be considered more effective than DWI1000 and at least as effective as DWI1500.