Diagnosis Of Pancreatic Carcinoma With Multi-Sequence Of MRI And Investigation Of The Specific Sign Of MRCP

Objective: To investigate the value of multi-sequence united diagnosis for pancreatic carcinoma and the specific MRCP sign for pancreatic head cancer. Materials and Methods: Thirty-three patients suspected having pancreatic tumors underwent MR Imagng including T1WI, T2WI, fat-saturation sequence, MRCP and dynamic contrast sequence. Two blinded radiogists analyzed the whole scaned images and described the size, signal of tumors and morphology, the maximum ductal diameters of pancreatic duct in the head, body and tail of pancreas respectively. The CNRs between the tumor and normal pancreas were calculated also. The results were correlated with surgery, pathology and follow-up findings. Results: Final malignant and benign dignoses were determined in 20(61%) and 13(39%) patients respectively. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value are 95%, 81%, 89.5%, 88%, 91.5% respectively。The CNRs of artieal-phase and after Gd-DTPA administration are higher than that of before contast medial administration significantly (P<0.01), but no difference between delay-phase and before contast medial administration (P>0.05). The CNRs of portal-venous-phase are higher than that of arterial-phase(32.89±5.084 vs 25.15±2.977,P<0.01). With the four-segment sign as the creiterion of pancreatic head cancer, we found a specificity of 100% and a positive predictive value of 100% respectively but that of 69% and 60% for double-duct sign. Conclusion: MRI is important in diagnosis of pancreatic carcinoma and combined use of multi-sequence is more valuable. The best scan phase is portal-venous-phase which can display the highest CNR. Both double-duct sign and four-segment sign are important and predictive in diagnosis of pancreatic carcinoma, while the four-segment sign is more specific and may be regarded as a specific MRCP sign for pancreatic head cancer. The source image especially selective-reconstruced MRCP image which can increase both rate of four-segment sign and quality of MRCP is important in analysis of MRCP.