Diffusion measurement of intraplaque hemorrhage and intramural hematoma using diffusion weighted MRI at 3T in cervical artery.

Objectives: To assess the difference between carotid haemorrhagic plaque and non-haemorrhagic plaque by using diffusion-weighted imaging (DWI) and to evaluate carotid intraplaque haemorrhage (IPH) and intramural hematoma (IMH) of cervical artery dissection with apparent diffusion coefficient (ADC) measurement.

Methods: Fifty-one symptomatic patients underwent 3.0-T carotid MR imaging, including conventional sequences, three-dimensional (3D) magnetization-prepared rapid acquisition gradient-echo (MPRAGE) sequence, and DWI. Thirty-nine patients with carotid plaque and eight patients with IMH of cervical artery dissection were finally included. The groups of hemorrhagic plaque, non-hemorrhagic plaque and IMH were divided according to 3D MPRAGE sequence. ADC values of different groups were measured, and t tests were performed.

Results: The mean ADC values of hemorrhagic plaques, non-hemorrhagic plaque and IMH were (1.284 ± 0.327) × 10(-3)mm(2)/s, (1.766 ± 0.477) × 10(-3)mm(2)/s, and (0.563 ± 0.119) × 10(-3)mm(2)/s, respectively. The mean ADC values of hemorrhagic and non-hemorrhagic regions in the hemorrhagic plaque group were (0.985 ± 0.376) × 10(-3)mm(2)/s and (1.480 ± 0.465) × 10(-3)mm(2)/s, respectively. The differences between the hemorrhagic plaque and non-hemorrhagic plaque, hemorrhagic region and non-hemorrhagic region in hemorrhagic plaque, and the hemorrhagic region in the hemorrhagic plaque and IMH of artery dissection were significant (P < 0.05).

Conclusion: DWI may be a useful complement to conventional MR imaging for identifying haemorrhage of carotid plaques and differentiate IMHs from IPH.

Key Points: • ADC values of IPH are lower than the plaque without IPH. • DWI might be a useful complement to identify IPH. • IMH may be differentiated from IPH by using DWI.