磁共振弥散峰度成像诊断急性脑梗死的应用价值

A study on the clinical application of MR diffusion kurtosis imaging in cerebral infarction

目的初步探讨磁共振弥散峰度成像(DKI)技术在诊断急性脑梗死中的应用价值。方法对27例临床诊断为超急性-急性脑梗死患者行常规MRI平扫检查和DKI检查,其中超急性脑梗死1例,急性脑梗死26例。分析27例脑梗死的DWI和DKI图像特点,并测量26例急性脑梗死病灶侧与对侧相应正常组织的MD、AD、RD、MK、AK、RK值,比较病灶侧与对侧正常组织各值的差异。结果 1例超急性脑梗死的MK图在脑梗死1 h内能清楚显示脑梗死核心区域,MK图显示的异常信号区范围小于DWI图异常信号区;发病3个月随访发现MK和DWI异常信号重叠的区域呈FLAIR低信号;而MK和DWI不匹配的区域,在FLAIR图像呈稍高信号。26例急性脑梗死病灶侧的MD、AD、RD值均较对侧相应正常组织减低,病灶侧的MK、AK、RK值均较对侧相应正常组织增高,DKI参数(MK、AK、RK)的变化百分比明显比DTI参数(MD、AD、RD)的变化百分比大。结论 (1)DKI能有效评估超急性脑梗死组织的预后,DKI和DWI异常信号重叠区域趋向于梗死,而DKI和DWI异常信号不匹配区域趋向于恢复;(2)DKI比DTI更敏感检测脑梗死灶的发生及其演变过程,有助于对超急性-急性脑梗死的诊断及预后评估。

Objective To evaluate the diagnostic value of diffusional kurtosis imaging theory in acute cerebral infarction. Methods Twenty-seven patients with cerebral infarction （hyperacute infarction in 1 case and acute infarction in 26 cases） were scanned with conventional MRI and DKI sequences. All images of DWI and DKI were analyzed, the MD/AD/RD/MK/AK/RK value of lesion side and contralateral side were measured. Results In the case of hyperacute cerebral infarction, the abnormal area can be detected clearly in the DWI and MK maps, the visible volume of the MK lesions were smaller than in DWI. Three months later, the abnormal area that showed up in both MK and DWI images also showed up with low signal in FLAIR. The MD/AD/RD values in 26 cases with acute cerebral infarction decreased compared with contralateral side, while the MK/AK/ RK values increased. Conclusion DKI could be used to effectively assess the prognosis of hyperacute cerebral infarction organization. Abnormal areas showed up in both DKI and DWI indicated infarction and softening lesion. Abnormal area showed up in only one of the DWI/DKI would probably recover; DKI could showed the heterogeneity of acute cerebral lesions, suggested that the inconsistency of ischemic tissue prognosis. DKI could be a useful complementary tool for the clinical diagnosis of acute cerebral infarction. Compared with the traditional DTI, DKI could be more sensitive to detect acute cerebral infarction and its dynamic changes, DKI could contribute to the clinical diagnosis and prognosis of hyperacute and acute cerebral infarction.