The Experimental And Clinical Study Of The Three Dimensional Dynamic Contrast Enhanced Magnetic Resonance Angiography

ABSTRACTObjective: To compare 3D DCE MRA(Three dimensional dynamic contrast enhanced magnetic resonance angiography) with DSA(Digital subtracted angiography) in assessing vascular stenosis of animal model. And to probe the technique of 3D DCE MRA at different territories and features of vessles, and assess the value of clinical application for diagnosis, taking operation or DSA as gold standard, which could provide the objective, exact and non-invasion imaging diagnosis evidences for assessing the type, degree and range of vascular diseases. Method: 1. Experiment models with Stenotic femoral arteries were established in six caninewith 6 mild stenosis (26% of degree) and severe stenosis (65% of degree). Stenotic vessles were examinated by means of 3D DCE MRA and DSA. And the degree and length of target Stenotic vessles were measured respectively. The results of 3D DCE MRA were compared with the findings on DSA.-6-2. Among patients suspected of vascular disease underwent 3D DCE MRA. 75 of them had various aortic and major branches lesions and 21 were normal. 63 cases (47 patients and 16 normal) were identified by surgery and/or DSA. 82 cases underwent DLJS (Doppler ultrasonography) simuteniously. According to different territories, the target vessles were divided into four groups, including aorta, carotid arteries, portal vein and peripheral vasculature. The acquisitive sequence was 3DT|-FFE, and the scanning parameters, injection dose and velocity and calculation of delay time (bolus test or BolusTrak) were determined on the basis of location and features of the target vessles. Some cases underwent subtraction and MobiTrak to improve the image quality and enlarge FOV. After the image quality was evaluated, all cases were diagnosed by two doctors in double-blind method. The results were statisticsed and the sensitivity, specificity and accuracy of 3D DCE MRA were calculated, taking operation and/or DSA as standard.Result:1. The degree of stenosis measured by 3D DCE MRA was higher than that of DSA. especially for severe stenosis. There was no significant difference between 3D DCE MRA and DSA. (analysis of variance P>0.05).2. All cases were classified as good image quality. The rate of satisfactory of vessel visualization for 3D DCE MRA was 100%.63 cases were identified by surgery and/or DSA, and the fasle positive in 2, fasle negative in I .The sensitivity, specificity and accuracy of 3D DCE MRA were 100%, 100% and 100% for aorta. 100%.75.0% and 92.9%for carotid arteries, 100%, 75% and 93.3%for portal vein and 93.3%, 80% and 90% for peripheral vasculature respectively. The total sensitivity, specificity and accuracy were 97.9% , 81.3 % and 93.7%.-7-Conclusion:1. 3D DCE MRA is accurate and reliable for determination of the degree and length of stenosis. There is no significant difference between 3D DCE MRA and DSA. but the value of the stenotic degree of 3D DCE MRA may be overestimated.2. 3D DCE MRA is a safe and reliable technique of MR angiography, demonstating most of vessles and diseases. It is a valuable imaging method to detect and diagnose the vascular diseases of aorta, carotid arteries, the portal vein and peripheral vasculature. It is also important to combine MRI technique. 3D DCE MRA was superior to DUS in diagnosis of vascular diseases, evaluated by surgery and DSA, especially for the portal vein system and peripheral vasculature. This method possesses great potential of clinical application. With the improvement of imaging, it can possibly and progressively replace DSA in the future.