Application Research Of High Magnetic Resonance Perfusion Weighted Imaging In Pancreatic Cancer

Objective: To investigate the magnetic resonance manifestations of normal pancreas and pancreaticcarcinoma, analyze the diagnostic value of high-field magnetic resonance perfusion imaging of pancreaticcancer.Methods: Thirty-three patients with pancreatic cancer underwent high field magnetic resonance perfusionimaging, Patients were aged forty-one and seventy-six years and the median age was six point fifty-twoyears, fourteen cases were female and nineteen were males. All the cases were proved by operationpathology or symptom, lab examination and imaging findings. Twenty-four cases occurred in the head ofpancreas, and nine cases in pancreatic body or tail. According to the International Association UICC onclinical stage for pancreatic cancer (1992): two cases in stageⅠ, eleven cases in stage II, fifteen cases instage III, five cases in stage IV. All patients were scanned by conventional MR imaging firstly, and thendynamic contrast-enhanced perfusion imaging (PWI) and the last routine enhanced scanning. MR scanusing body surface coil phased array scanned the upper abdomen and the whole pancreas. Axialrespectively used T1WI-TSE fast spin echo sequence, T1WI-VIBE with fat suppression sequences,T2WI-Blade with fat suppression sequences and diffusion weighted imaging (b=50, b=800), and coronalused T2WI-Haste sequence Fourier acquisition single-shot fast spin echo. PWI using Turbo-flash2Dsequence scanned the selected dimensions continuously for50dynamics and each dynamic included6layers; a total of300images were obtained. contrast agent (Gad-DTPA) and an equal amount ofphysiological saline were both injected from hand vein or median cubical venous with a dose of0.2mmol/Kg, using a high pressure syringe, at a rate of3ml/s. Images were analyzed using GermanSiemens mean curve software to get time signal curve and signal strength values, at the same time calculateperfusion parameters including slope (Slop), peak (peak enhancement PE), time to peak (TTP) and signal enhancement ratio (SR)Results: Thirty-three cases of pancreatic cancer could be seen obvious signal abnormalities area in the headof pancreas or the body and tail, twenty-four cases of which were found pancreatic head area or region ofhead and neck had bump, four cases with bump in pancreatic body and tail. The boundary of bumps werenot clear, The solid components of tumor were low signal on T1WI, slightly high signal on T2WI; fatsuppressed sequence and DWI both showed high signal performance. Some larger masses had the necroticcomponents, which showed low signal on T1WI, high signal on T2WI. The other five patients were notfound obvious bump, only showing the diffusing enlargement of pancreatic body and tail and the abnormalsignal, low signal on T1WI, slightly high signal on T2WI. Twenty of all patients appeared pancreatic ductcircuity and common bile duct and pancreatic duct expanded, forming double tube sign. Twelve cases ofabove patients appeared multiple liver metastases, fifteen cases with lymph node metastasis and elevencases with superior mesenteric vascular or portal vein invasion. TIC of pancreatic cancer areas showed aslow rising trend continuously, with no wave, and its perfusion parameters Slop, PE, SR were all less thanthe tumor periphery and the normal area, while the TTP was prolonged, the differences among them werestatistically significant; TIC of the tumor periphery and the normal area were both rising fast to reach peakin early stage, but PE and Slop in the tumor periphery were lower than that in normal Zone, TTP was lowerdelay than that in normal area, After reaching peak TIC of normal areas decreased, while the tumorperiphery areas maintained a platform or a slow ascendant trend. At the same time, Slop, TTP and SR ofpancreatic lesion between stageⅠ, Ⅱand stageⅢ, Ⅳwere all not significantly different, TIC shape trendof these lesion area was slowly rising state, no wave, TIC of necrotic area was a similar flat curve.Conclusion: High field strength MR imaging with high resolution of soft tissue can clearly shows theboundary and form of the tumor tissue and normal pancreatic, making the tumor and normal pancreatic tissue signal contrast more apparent. At the same time, the conventional enhanced scanning and PWI canreflect tumor internal blood perfusion status; understanding hemodynamic changes, thereby improving thetumor detection rate and the accuracy of qualitative diagnosis.