联合MRI常规与弥散成像判断多发性硬化斑块的病理基础

目的：研究MRI常规与弥散成像（DWI，DTI）联合应用，在判定多发性硬化斑块病理基础中的价值。材料和方法：对14例脑部多发性硬化病例进行联合MRI常规及弥散加权（DWI）、弥散张量成像（DTI）。其中1例为继发进展型（SP型），13例为好转－复发型（RR型）。首次发作期（急性斑块）成像者5例，缓解期（慢性斑块）成像者9例。分析常规MRI T1WI、T2WI及DWI、DTI成像后所获得的ADC图、FA图上的信号改变，量化分析DTI成像中的平均D值及各向异性指数AI值。结果：急性与慢性MS斑块MRI表现明显不同。急性MS斑块较大，斑块内信号不均匀，大致可以分为两部分：中心为数毫米至2cm不等的圆形或卵圆形异常信号影，呈T1WI低、T2WI高信号，推测病理为脱髓鞘或轴索丢失。周围为片状不规则形T1WI略低、T2WI略高信号影，考虑为水肿。发作MS斑块DWI可呈现高信号，e指数ADC图亦可呈现高信号，但范围后者明显小于前者。斑块中心平均D值升高、AI值明显下降，周围ADC值亦升高，但不如前者明显，AI值无明显改变，支持常规MRI关于斑块病理的推测。慢性MS斑块较小，多呈小片状或宽条状分布于侧脑室旁，T1WI呈略低信号、T2WI高信号。DWI呈近等信号、e指数ADC图呈等或略低信号。斑块平均D值不同程度升高，AI值下降，提示为脱髓鞘或轴索丢失，而无水肿存在。结论：联合MRI常规与弥散成像可以判断多发性硬化斑块的病理，从而进一步加深了对MS斑块病理的认识。

Combined Conventional and Diffusion MRI in Determining the Pathological Changes of Multiple Sclerosis Lesions

Purpose: To evaluate the usefulness of combined conventional and diffusion MRI in determining pathological changes of brain multiple sclerosis lesions. Materials and Methods:A combined conventional and diffusion MRI(including DWK DTI) were obtained from 14 multiple sclerosis. One is secondary progressive multiple sclerosis (SPMS), thirteen is relapsing - remitting multiple sclerosis (RRMS) . Five cases are the first onset (which lesions are known as acute lesions) ,nine are in the period of remission (chronic lesions) .We investigated the lesions intensity in T1WK T2WI of conventional MRI. After obtaining mean diffusivity(D) and fractional anisotropy images and image coregistration, the lesion intensity in DWI and eADC mapping were also investigated. D and AI values were measured form six dots of MS lesion which can be seen in T2WI and compared to contralateral white matter.Results: There are signficantly different manifestation between acute and chronic MS lesions in MRI. Acute MS lesions are larger with inho-mogeneous intensity, which can be divided into two parts: core and surroundings.Core are round or oval shape with low intensity in T1 WI and high intensity in T2 WI. We infer the pathologic changes is likely demyelination and axonal loss . Surroundings appear irregular patchy with slightly hypointense in T1WI and hyperintense in T2WI, Which is likely edema. It suggested infarction inside acute lesions which are high intensity in DWI and eADC mapping. The results shown D value increased and AI values decreased in circle of acute lesions. Similar D value changes can be seen in surroundings , but AI value is almost normal . The chronic lesions are smaller patchy appearance beside the lateral ventricle which is slightly low intensity in T1 WI and high intensity in T2 WI. For chronic MS lesins, D value were higher and AI value low in lesions than control white matter, which suggested its pathological changes are demyelination and ax-onal loss,but no emeda.Conclusion: A combined conventional and diffusion MRI(including DWKDTI) can determined the pathological changes of the acute and chronic MS lesions. The measurement of D and AI values supported the judgement of pathological changes in MS lesions in differential period.