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Objective To compare monopolar (MP) and bipolar (BP) diffusion weighted imaging (DWI) in detecting small liver metastases. Materials and methods Eighty-eight patients underwent 3-T MRI. The signal-to-noise ratios (SNR) of the liver parenchyma and lesions, the lesion-to-liver contrast-to-noise ratios (CNR), and the detection sensitivities were compared. The lesion distortion was scored (LDS) from 4 (no distortion) to 1 (excessive distortion), dichotomised as no-distortion and distortion, and the association between detected lesions for each reader in the MP or BP DWI group and the dichotomised lesion distortion degree was assessed. Result Forty-six hepatic metastases were confirmed. The CNR with BP images showed significantly higher values than with MP (P = 0.017). The detection sensitivities of the three readers were higher in the BP sequence than in MP, and one reader detected significantly more hepatic lesions with BP images (P = 0.04). LDS was significantly improved with BP sequence (P = 0.002). In the no-distortion group, excluding the MP DWI assessments of one reader, detection sensitivities were significantly higher than in the distortion group (P < 0.001 and P = 0.002, respectively). Conclusion Reduced lesion distortion improves the detection of small liver metastases, and BP is more sensitive in detecting small liver metastases than MP DWI. [ABSTRACT FROM AUTHOR]

Objective. The objective was to investigate the relationship between prognosis in case of pancreatic cancer and perfusion in tissue surrounding pancreatic cancer using perfusion CT. Methods. We enrolled 17 patients diagnosed with inoperable pancreatic adenocarcinoma. All patients were examined by perfusion CT and then underwent chemotherapy using gemcitabine. The time density curve (TDC) of each CT pixel was analyzed to calculate area under the curve (AUC) and blood flow (BF) using a mathematical algorithm based on the single-compartment model. To measure the AUC and BF of tumor (AUCT and BFT) and peritumoral tissue (AUCPTT and BFPTT), regions of interest were manually placed on the cancer and in pancreatic tissue within 10mm of proximal pancreatic parenchyma. Survival days from the date of perfusion CT were recorded. Correlation between AUC or BF and survival days was assessed. Results. We found a significant correlation between AUCPTT or BFPTT and survival days (P = 0.04 or 0.0005). Higher AUCPTT or BFPTT values were associated with shorter survival. We found no significant correlation between AUCT or BFT and survival. Conclusions. Our results suggest that assessments of perfusion in pancreatic tissue within 10mm of proximal pancreatic parenchyma may be useful in predicting prognosis. [ABSTRACT FROM AUTHOR]