Low Field MRP of Portal Vein and Its Application in Portal Vein Obstruction Diseases

Objective:To investigate the technique essentials of low field magnetic resonance portography (MRP) of portal vein and its application in portal vein obstructive diseases.Methods:We collected 102 patients' data of low field MRP of portal vein,in which 30 cases were normal and 72 cases were abnormal.Using 2D FFE sequence to test the circulation time of contrast agent,according to the formula: delay time= cycle time - 1/4 acquisition time,computed out delay time.Using high-pressure syringe to inject contrast agents(0.2mmol/kg) into one side elbow vein,using 3D FFE sequence to do coronal scan, the portal vein data of the second group underwent maximum intensity projection(MIP).Results:In 102 patients,30 patients' MRP were normal,it can clearly show the portal trunk and intrahepatic branch veins of more than five classes,and also can clearly show splenic vein and mesenteric vein.72 cases were abnormal,in which 28 cases were hepatocellular carcinoma with portal vein tumor thrombus,19 cases were portal vein thrombosis,11 cases were cirrhotic portal hypertension,21 cases were portal vein stenosis,of which 2 cases of hepatic duct carcinoma,1 case of huge gastric fundus mass,3 cases of giant hemangioma in right liver lobe,12 cases of enlarged lymph nodes in hepatic hilar region,3 cases of pancreatic head mass.Conclusion:Dynamic enhanced MRP technique of portal vein can be well applied in low field MRP machines,the imaging effect has no significant difference comparing with high-field MRP machine,it can well display the structure and intrahepatic branches of portal vein,and can accurately evaluate the portal vein obstructive lesions.