数字减影-时间飞跃磁共振血管造影的临床应用研究

目的评价数字减影-时间飞跃磁共振血管造影(DS-TOF MRA)在亚急性及慢性脑出血中的临床应用价值。资料与方法58例T1WI呈高信号的亚急性、慢性脑内血肿患者,行常规静脉血流饱和3D-TOF MRA序列(A)及反向动脉血流饱和3D-TOF MRA序列(B),应用数字减影方法,将反向动脉血流饱和B序列源图像作为蒙片,A序列源图像减去B序列源图像即为DS-TOF MRA的源图像,将其进行最大信号强度投影(MIP)重建产生无高信号组织背景干扰的DS-TOF MRA图像。测量血肿区对比度/噪声比(C/Ns)值并比较动脉血管边缘的显示情况,对减影效果进行评价。结果除2例患者因运动而无法产生清晰图像外,其余56例在3D-TOF MRA上有高信号背景组织干扰影像,在DS-3D MRA图像上均被完全消除。DS-TOF MRA源图像血管-血肿区C/Ns值为19.30±1.72,常规TOFMRA源图像血管-血肿区C/Ns值为2.62±0.31(t=17.3828,P<0.01)。DS-TOF MRA源图像血管-血肿区C为(1.40±0.01)%(P<0.01)。减影后DS-TOF MRA图像脑动脉管壁显示情况明显优于常规TOF-MRA(u=-8.8452,P<0.01)。结论DS-TOF MRA能有效消除常规TOF MRA源图像血肿高信号对血管影像的干扰,增加血管与周围组织的对比度,有利于准确地评价脑动脉的病变

Clinic Application of the Digital Subtraction TOF Magnetic Resonance Angiography

Objective To evaluate the clinical application of digital subtraction time of flight magnetic resonance angiography(DS TOF MRA) in chronic and subacute intracerebral hematoma.Materials and Methods 58 patients of chronic and subacute intracerebral hematoma with hyperintensity on T_1W,were performed with venous flow saturation(sequence A) and arterial flow saturation(sequence B).Then the resultant images were the DS TOF MRA,which were acquired by means of sequence B subtraction from sequence A and reconstructed by means of MIP technique.Hematomas were evaluated by means of contrast to noise ratio(C/Ns).Visualization grades of cerebral arterial edge were compared between DS TOF MRA and conventional TOFMRA.Results 56 cases of DS TOF MRA,except 2 cases with motion artifacts,were eliminated the short T_1 hyperintensity signal in background secondary to chronic and subacutal intracerebral hematoma seen on the conventional 3D TOF MRA with venous flow saturation.C/Ns was 19.3 1.72 for DSTOF MRA and 2.62 0.31 for conventional TOF MRA.All the hemotomas had lower C/Ns on conventional TOF MRA than that on DS TOF MRA(t=17.3828,P<0.01).The results of visualization grades of cerebral arterial edge with DS TOF MRA were superior to that with conventional TOF MRA(u=-8.8452,P<0.01).Conclusion DS TOF MRA is valuable to avoid the influence of hyperintensity by hematoma on the conventional TOF MRA,it is helpful to correctly evaluate the lesions of cerebral arteries.