双指数表观弥散系数对颈内动脉狭窄者大脑的评价  

Biexponential apparent diffusion coefficients in brain with stenosis of internal carotid artery

作　　者：彭雯佳[1] 陆建平[1] 王敏杰[1] 金爱国[1] 方亮[1] 陈士跃[1] 黄挺[1] 

机构地区：[1]第二军医大学附属长海医院放射科,上海200433

出　　处：《实用放射学杂志》2013年第4期512-516,538,共6页Journal of Practical Radiology

摘　　要：目的以单侧颈内动脉（internalcarotidartery，ICA）不同狭窄程度的患者为研究对象，比较弥散加权成像的双指数模型、单指数模型的各参数值在狭窄侧与对侧大脑半球之间的差异。方法对本院经头颈部动脉CTA检查发现无动脉狭窄或仅有单侧ICA狭窄患者．在无MRI检查禁忌并患者知情同意的前提下，进行头颅的弥散加权成像（diffusionweightedimaging，DWI）检查。本研究采用双指数和单指数2种模型，b值序列是：0、5、10、20、50、100、200、400、600、1000、l500、2000、3000s／mm。，通过后处理工作站计算单指数表观弥散系数（monoexponentialADC）和双指数的快ADC（FastADC）、慢ADC（SlowADC）以及快ADC的分数（fractionoffastADC）。根据颈内动脉是否狭窄及狭窄程度将患者分为无狭窄组、轻／中度狭窄组、重度狭窄／闭塞组，统计各组左右两侧大脑中动脉供血区的各参数值．运用非参数秩和检验法比较各组之间两侧值的差异。结果收集符合条件的患者52例，其中无狭窄组10例、轻／中度狭窄组23例，重度狭窄／闭塞组19例。在ICA狭窄者中，狭窄侧的M0noexponentialADC值、FastADC值、SlowADC值均大于对侧的值。从无ICA狭窄组至重度狭窄／闭塞组，Monoexpon㈨tialADC值和SlowADC值左、右侧之差的绝对值也随着狭窄程度的加重而逐渐升高，各组之间的差异有统计学意义（P一0．0046和P一0．0054）。FastADC值双侧之差的绝对值在无狭窄组最大，重度狭窄／闭塞组次之，轻／中度狭窄组最小，各组的差异有显著性（P一0．0368）。FractionofFastADC值双侧之差的绝对值在重度狭窄／闭塞组最大．无狭窄组次之，轻／中度狭窄组最小，但各组的差异无娃著性（P一0．6443）。结论与单指数模型相似，双指数的多b值衰减模型能定量反映ICA狭窄与否及不同狭窄程度对大脑组织的弥散状态的影响．将来可能为�Objective To compare the differences of parameters of diffusion weighted imaging （DWI） with both biexponential and monoexponential model between affected and opposite cerebral hemisphere in patients with unilateral stenosis of internal carotid ar- tery {ICA}. Methods From June to August, 2011, patients who had no stenosis arteriostenosis or had only unilateral stenosis of ICA which diagnosed by CTA, and had no MR imaging contraindication and signed the informed consent underwent DWI at both biexponentiaI and monoexponential decay model, the b-values were 0, 5, 10, 20, 50, 100, 200, 400, 600, i000, 1500, 2000, 3000 s/ramz. Then apparent diffusion coefficients （ ADCs} of Monoexponential model, and Fast ADCs, Slow ADCs, Fraction of Fast ADCs of bi-exponential model were calculated through workstation. According to the stenotic degrees of ICA, patients were divided as following three groups： no stenotic group, mild/moderate stenotic group, and severe stenotic/occlusive group. Every parameters of both cerebral side in every groups were calculated, and compared the differences among groups for Wilcoxon rank sum test. Results Fifty-two patients were enrolled in our study, among whom Kruskal Wallis cases in no stenotic group, 23 cases in mild/moderate stenotic group, and 19 cases in severe stenotic/occlusive group. In the patients with ICA stenosis, Monoex ponential ADC, Fast ADC and Slow ADC on the affected sides were higher than that in the opposite sides. The differences between affected and opposite side of Monoexponential ADC and Slow ADC increased along with the severity of ICA stenosis, and the differ- ences among groups had statistical significance was highest in no stenotic group, followed by s （P=0.0046 and P=0.0054）. The absolute different value of Fast ADC in bilateral stenotic/occlusive mild/moderate betw stenotic group, there was no of een group （P = 0. 0368）. The differences of fraction of Fast ADC were lower in no group than those in severe stenotic/occlusive group, were low est in mild/mo

关 键 词：脑 磁共振成像 双指数衰减 颈内动脉 

分 类 号：R322.81[医药卫生—人体解剖和组织胚胎学] R445.2[医药卫生—基础医学]