A Study Of Diffusion Weighted MRI Applied To Carotid Intraplaque Hemorrhage And Cervical Artery Dissection

ObjectiveTo assess carotid hemorrhagic plaque and nonhemorrhagic plaque with ADC measurement, and evaluate carotid intraplaque hemorrhage and intramural hematoma of cervical artery dissection with ADC measurement to determine whether it is useful to differentiate intraplaque hemorrhage and intramural hematoma by diffusion weighted imaging (DWI) sequence.Materials and MethodsThis study was approved by the Review Board of Shandong Medical Imaging Institute, and informed consents were obtained.51 patients who had symptomatic cervical artery stenosis were enrolled from the department of neurology at Shandong Provincial Hospital in this study. Ten patients among these patients were highly suspected or diagnosed spontaneous cervical artery dissection by digital subtraction angiography (DSA). MRI was performed on a 3.0T MR scanner (Philips Achieva TX, Best, the Netherlands) with a cervical eight-channel phased-array surface coil. High-resolution MRI protocols included 3D-TOF (three-dimensional time of flight)、 T2WI (T2 weighted imaging)、T1WI (T1 weighted imaging)、PDWI (Proton density weighted imaging)、3D-MPRAGE (3D magnetization-prepared rapid acquisition gradient-echo) and DWI sequences. All images were assessed by two experienced radiologists and unqualified images were excluded. The group of hemorrhagic plaque and non hemorrhagic plaque were divided according to obvious hyperintense on 3D-MPRAGE sequence, and the portion of hemorrhage and non hemorrhage in the group of hemorrhagic plaque were delineated by 3D-MPRAGE sequence. Intramural hematomas of cervical artery dissection were determined by 3D-MPRAGE sequence as well. The ADC values of group of hemorrhagic plaque and non hemorrhagic plaque, the portion of hemorrhage and non hemorrhage in the group of hemorrhagic plaque and Intramural hematomas of cervical artery dissection were measured and recorded. Statistical analysis was utilized by SPSS V20.0 statistical software. The differences of ADC values of group of hemorrhagic plaque and non hemorrhagic plaque, the portion of hemorrhage and non hemorrhage in the group of hemorrhagic plaque and Intramural hematomas were analyzed with independent samples t-test. P<0.05 was considered statistically significant in this study.ResultsFinally 38 available patients with carotid plaque and 8 available patients with intramural hematoma of cervical artery dissection were included. Fifty-two plaques were detected from the 38 available patients with carotid plaque:19 hemorrhagic plaques,33 nonhemorrhagic plaques. The mean ADC values of group of hemorrhagic plaque and non hemorrhagic plaque were (1.284±0.327), (1.766±0.477)×10-3 mm2/s, respectively. The difference of group of hemorrhagic plaque and non hemorrhagic plaque was significant (t=-3.90, P<0.05). The mean ADC value of hemorrhagic and non-hemorrhagic portion in group of hemorrhagic plaque were (0.985±0.376), (1.480±0.465)×10-3 mm2/s. Significant difference of the mean ADC values between hemorrhagic and non-hemorrhagic portion in group of hemorrhagic plaque was revealed (t=-3.61, P<0.05). The mean ADC value of intramural hematoma was (0.563±0.119)×10-3 mm2/s, the difference of the mean ADC values between the portion of hemorrhage in the group of hemorrhagic plaque and intramural hematoma was significant (t=3.07, P<0.05)ConclusionThe hemorrhagic and non hemorrhagic plaques can be distinguished by DWI and the ADC value of overall plaque would reduce due to intraplaque hemorrhage. Thus DWI can be a useful complement to conventional high-resolution MRI for identifying hemorrhage of atherosclerotic plaques. Carotid intraplaque hemorrhage and intramural hematomas of cervical artery dissection can be differentiated by ADC measurement and it indicates that DWI may be a new method used to differentiate carotid intraplaque hemorrhage which has similar imaging findings with intramural hematomas of cervical artery dissection.