正常人脑白质ADC值与年龄的相关性研究

目的探讨不同年龄组正常人脑白质的ADC值的特点及规律,建立正常人脑不同部位白质的标准ADC值,为弥散的临床应用及研究提供客观依据。方法收集60名正常健康体检者,对所有研究对象行头颅常规MR检查及平面回波弥散加权成像检查,获得各相同性弥散加权图。每个研究对象选16个感兴趣区,通过公式ADC=ln（S低／S高）／（b高-b低）计算每个感兴趣区的平均ADC值。结果正常人脑白质总的平均ADCave值为0．76±0．03（0．65～0．83）×10^-3mm^2／s,白质的平均ADC值随着年龄增长而增加,与年龄呈正相关,相关系数为0．46。结论不同年龄组正常人脑白质的ADC值有一定的变化规律,在临床对疾病的诊断时要考虑到该变化,以免误诊和漏诊;弥散定量测量在一定程度上可以用来评价正常人脑随着年龄增长伴随微观水平的改变,弥散技术有可能在脑老化研究中起到举足轻重的作用。     

多系统萎缩和帕金森病患者的磁共振影像学分析

目的 探讨多系统萎缩(multiple system atrophy,MSA)和帕金森病(Parkinson disease,PD)的磁共振成像(MRI)影像学特点,为早期诊断和鉴别诊断提供依据.方法 回顾性分析经临床确诊的24例MSA、30例PD和30例健康人的MRI资料,观察指标包括:(1)T2WI信号改变:十字征(即脑桥基底部十字样高信号)、裂隙征(即壳核外侧缘裂隙样高信号);(2)脑室、脑池扩大:四脑室、桥池、延池;(3)脑实质萎缩:延髓、脑桥、小脑中脚、壳核萎缩.并测量中脑面积、脑桥面积和小脑中脚宽度.结果 MSA患者中均出现至少1项MRI异常指标,并表现一定的分型差异.敏感性较高的指标是:小脑中脚萎缩(79.2%)、脑桥萎缩(79.2%)和十字征(75.0%);特异性和阳性预测值高的指标是:十字征(均为100%)、裂隙征(均为100%)、小脑中脚萎缩(93.3%和90.1%)、脑桥萎缩(96.7%和95.0%).MSA组脑桥面积、中脑面积及小脑中脚宽度分别为(288.7±75.4)mm2、(127.8±25.8)mm2及(10.7±2.8)mm,与PD组[分别为(477.5±54.3)mm2、(145.9±21.6)mm2及(16.2±1.3)mm]、对照组[分别为(454.5±36.8)mm2、(146.4±17.4)mm2及(16.7±1.2)mm]比较,差异有统计学意义(P＜0.05).结论 MRI有助于MSA的诊断及其与PD的鉴别诊断,对MSA的分型具有一定的价值.

Abstract：

Objective To explore the MRI features of patients with multiple system atrophy (MSA) and Parkinson's disease (PD) for providing early evidence in differential diagnosis. Methods The MRI features of 24 patients with MSA, 30 patients with PD and 30 healthy people as controls were retrospectively analyzed. Abnormal intensity in MRI included the hot-cross bun sign and the slitlike changes. The atrophies of brain included cerebellar, middle cerebellar peduncles, medulla oblongata and pon. Cerebral ventricle dilatation included fourth ventricle and cisterna pontis. The midbrain area, pons area and middle cerebellar peduncles width were measured. Results All patients with MSA had at least one of the features observed on MR images, and there were some differences in the subtypes of MSA. The high sensitive features were the atrophies of middle cerebellar peduncles (79.2%), the atrophies of pons (79.2%) and the hot-cross bun sign (75.0%). The parameters with high specificity and high positive predictive value were hot-cross bun sign (both 100%), the slit-like sign (both 100%), the atrophies of middle cerebellar peduncles (93.3% and 90.1%), and the atrophies of pons (96.7% and 95.0%). MSA group had the statistically significantly decreased values of pons area, midbrain area and middle cerebellar peduncles width [(288. 7±75. 4) mm2, (127.8±25.8) mm2 and (10. 7±2.8) mm, respectively], as compared with PD group [(477. 5 ± 54. 3) mm2, (145.9±21.6) mm2 and (16.2±1.3) mm, respectively] and healthy group [(454. 5±36. 8) mm2 , (146.4±17.4) mm2 and (16.7±1.2) mm, respectively] (all P ＜0. 05). Conclusions The routine MRI is helpful in differential diagnosis between MSA and PD and has some values in diagnosing the subtypes of MSA.