| [Objective] 1. To evaluate the quality of images obtained with sequences of three-dimensional fast imaging with steady-state procession (3D-FISP) and three-dimensional fast low angle shot (3D-FLASH),and further to elucidate the diagnostic value of three-dimensional dynamic contrast-enhanced magnetic resonance angiography (3D DCE MRA) applied to the lesions of the abdominal blood vessels and the variations in the intrahepatic portions of the hepatic and portal veins through animal experiments and clinical applications of 3D DCE MRA. 2. To elucidate the accuracy and the clinical value of bolus tracking technique (BTT) and phase mapping (PM) applied to determining the hemodynamics of the portal vein.[Materials and Methods] 1. Animal experimental study on 3D DCE MRA:5 rabbits were examined by MRA with sequences of 3D-FISP and 3D-FLASH,and CT angiography (CTA). After scanning,the images were reconstructed with the method of maximum intensity projection (MIP). By using the technique of multiple planar reconstruction (MPR),the diameters of the abdominal aorta,the posterior vena cava,the portal vein,the anterior mesenteric artery and the renal arteries were measured in source images and MIP images on workstation. The signal intensity and the noise intensity of the above-mentioned blood vessels and the psoas were also measured and then the signal-to-noise ratio (SNR),and contrast-to-noise ratio (CNR) could be calculated. 2. Clinical study on 3D DCE MRA:3D DCE MRA was performed in 59 cases. Among them,54 cases were scanned with 3D-FISP sequence and 5 cases with 3D-FLASH sequence,9 cases were performed with digital subtract angiography (DSA),and 3 cases were examined with CTA. 3. Study on theflow quantitation of the portal vein:after fasting for about 8 hours before scanning,10 healthy volunteers and 15 patients with hepatocirrhosis underwent the examinations of the flow quantitation of the trunk of the portal vein including velocity,flow capacity and flow direction with BTT and PM. In the group of healthy volunteers,all cases were examined with Duplex US (DUS),and the value of DUS was considered as a reference standard. 4. All these data were analyzed with statistical methods of one-way ANOVA,t-test,least-significant difference,correlative and regression analysis.[Results] 1. Animal experimental study on 3D DCE MRA:(1) The values of the diameters (D) of the abdominal aorta at the level of the renal artery,medial segments of the portal vein and the posterior vena cava,the anterior mesenteric artery and the renal arteries in source images of different examinations had trends:D3D-nsp> DSD-FLASDCTA,and in MIP images,the trends were:DSD-FISPSD-FLASH,and the values of the differences (d) in diameters of the above-mentioned blood vessels between source images and MIP images had trends:dsD-FispsD-FLASH- There were no significant differences between these results in statistics (P>0.05). (2) The values of the SNRs of the above-mentioned blood vessels in source images or MIP images of 3D-FISP and 3D-FLASH sequences were all:SNR3D-Fisp< SNR3D-FLASH,and among them,there were significant differences in the SNRs of the anterior mesenteric artery and the renal arteries between these two sequences (P<0.05). And in source images,the values of the CNRs between the above-mentioned blood vessels and psoas were:CNRaD-FispNRsD-FLASH,there were no significant differences between these two sequences in statistics (P>0.05). (3) In MIP images of 3D-FISP sequence,the distal branches of the above-mentioned blood vessels were demonstrated better than that of 3D-FLASH sequence. 2. Clinical study on 3D DCE MRA:(1) Normal appearances:3 cases,the abdominal aorta,the vena cava,the portal vein and their major branches were all demonstrated clearly in the images of 3D DCE MRA. (2) Abdominal aortic aneurysm:12 cases,the involved segement of the aorta became deformed irregularly and the actual aneurysmal lumen wasdisplayed clearly. The thrombosis and the actual size of aneurysm could be seen in source images and pre-contrast images. (3) Aorti...
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