| Objective: To evaluate the capability of MR angiography techniques in displaying cerebral vessels; To evaluate the veracity of MRA in measuring the diameters of cerebral arteries and to upbuild normal MRA diameter values of cerebral arteries; To survey the variations of cerebral arteries on MR angiograms; To generalize MRA diagnostic and differentiable points of main cerebrovascular diseases, and the angiographic techniques for them. Materials and Methods: Th most ramus grades of cerebral arteries displayed were analyzed comparatively on MR angiograms and DSA in 43 cases to evaluate the difference in displaying cerebral arteries between 3D-TOF and high Venc 3D-PC MRA. The numbers of cerebral veins displayed were analyzed comparatively to differentiate the capability of displaying cerebral veins between 2D-TOF and lowVenc 3D-PC MRA.The diameters of 53 arteries in 5 cases were measured comparatively on MRA andon DSA images to evaluate the veracity of MRA in measuring the diameters ofcerebral arteries. Cerebral arteries diameters of 100 normal cases were measured,and their diversities in gender, ages and sides were analyzed to upbuild theirnormal values.MR angiograms of 204 cases were analyzed retrospectively to sum up the variationratios of cerebral arteries, their differences in gender and sides, in which the arterynot displayed was regarded as absence and the artery 1/2 diameter less than thesymmetrical one was regard as hypogenesis.MR angiograms of 90 cases of cerebrovascular diseases were analyzed includingarteriovenous malformation (AVM), arteriovenous fistula (AVF), aneurysm andstenosis or occlusion of cerebral arteries, to sum up the MRA signs of thesediseases, and to evaluate the veracity of MRA in displaying cerebrovasculardiseases by comparison to DSA.Results: The average grade of cerebral arteries displayed on MRA was 1 grade lessthan that displayed on DSA, and there was no obviously statistical difference between the average displayed on 3D-TOF MRA and that displayed on high Venc 3D-PC MRA (P>0.05). There was obviously statistical difference between the numbers of veins displayed on 2D-TOF and those displayed on low Venc 3D-PC MRA (PO.05), and the numbers on low Venc 3D-PC were more than those on 2D-TOF MRA.On measuring the diameters of cerebral arteries, MRA measurement was less than DSA, but the difference was much smaller (-0.1114mm+0.2817mm) between them. There was no significant difference on MRA diameters of most cerebral arteries in gender, age and sides, in few arteries but the difference was very much smaller, and was no practically meaningful.On the variations of cerebral arteries of 204 cases on MR angiograms, the hypogenesis and absence of ACA Al segment were seen in 10.8% and 8.3% separately, branching earlier of MCA in 1.5%, PCoA in 61.3%, fetaltype PCA in 29.9%, and the abnormal communicating arteries between ICA and BA system in 0.5%.MRA displayed the signs of main cerebrovascular diseases much better. The AVMs nidus on MR angiograms were much bigger than on DSA (P<0.05), and the number of draining veins on MRA was more than on DSA (P<0.05). The numbers of feeding arteries and draining veins were correlated to the lesion size positively. MR angiography displayed all signs of AVF displayed on DSA. The most diseases of AVF were carotid-cavernous fistula (4/8) and PCA-Galen fistula (2/8). Aneurysms located frequently in the main branches of cerebral arteries (8/9). MR angiogram is similar to DSA in displaying the sizes of aneurysms, superior to DSA in displaying the necks of aneurysms, and displayed 3 mm aneurysm in diameter well. The stenotic degree of cerebral arteries on MR angiogram was correlated to the severity of MRI manifestations positively, but very dispersively. The overestimation to artery stonesis is still in existence. MRA displayed the collateral pathways in stenosis and occlusion cases well.Conclusions: The evaluations of MR angiography techniques indicate that, the capability in displaying cerebral arteries of MR...
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