Grandin C B, Mathurin P, Duprez T, Stroobandt G, Hammer F, Goffette P, Cosnard G
Department of Medical Imaging, St Luc University Hospital, Catholic University of Louvain, Brussels, Belgium.
AJNR Am J Neuroradiol. 1998 Feb;19(2):245-52.
Our goal was to determine the accuracy of MR angiography at 0.5 T for the diagnosis of intracranial aneurysms.
We retrospectively studied 140 patients, 70 with acute subarachnoid hemorrhage, who were either at high or low risk for intracranial aneurysm. Three-dimensional time-of-flight MR angiography was typically performed to cover the circle of Willis, with a volume thickness of 30 mm. Conventional spin-echo MR images and MR angiograms were reviewed together, and the results were compared with those obtained at intraarterial cerebral angiography to determine the sensitivity and specificity of MR angiography.
Eighty-nine aneurysms (size range, 2 to 27 mm; 25 aneurysms < 5 mm) were identified at intraarterial cerebral angiography. Six aneurysms were missed by MR angiography and two were doubtful (sensitivity, 91% to 93%; specificity, 100%). Missed aneurysms were located outside the MR angiographic acquisition volume (n = 3) or on the carotid siphon (n = 3; size = 2, 3, and 5 mm).
Even if MR angiography presents some restrictions in acquisition volume and spatial resolution, the detection rate of intracranial aneurysms is excellent at 0.5 T in both asymptomatic patients and in those with subarachnoid hemorrhage. A midfield system is not a restriction to the detection of intracranial aneurysms by MR examination.
我们的目标是确定0.5T磁共振血管造影术诊断颅内动脉瘤的准确性。
我们回顾性研究了140例患者，其中70例为急性蛛网膜下腔出血患者，这些患者患颅内动脉瘤的风险有高有低。通常采用三维时间飞跃磁共振血管造影术来覆盖 Willis 环，容积厚度为30mm。同时回顾常规自旋回波磁共振图像和磁共振血管造影图像，并将结果与动脉内脑血管造影结果进行比较，以确定磁共振血管造影术的敏感性和特异性。
动脉内脑血管造影发现89个动脉瘤（大小范围为2至27mm；25个动脉瘤<5mm）。磁共振血管造影术漏诊了6个动脉瘤，2个结果存疑（敏感性为91%至93%；特异性为100%）。漏诊的动脉瘤位于磁共振血管造影采集容积之外（n = 3）或颈内动脉虹吸部（n = 3；大小分别为2mm、3mm和5mm）。
即使磁共振血管造影术在采集容积和空间分辨率方面存在一些限制，但在0.5T时，无症状患者和蛛网膜下腔出血患者颅内动脉瘤的检出率都很高。中场强系统并非磁共振检查检测颅内动脉瘤的限制因素。
