Usefulness of black-blood magnetic resonance angiography generated from vessel wall imaging after the stent-assisted treatment of intracranial arterial diseases

Abstract

Purpose After stent-assisted treatment for intracranial diseases, three-dimensional time-of-flight magnetic resonance angiography is a noninvasive follow-up method, but susceptibility artifacts prevent accurate evaluations of stented arteries. Sampling perfection with application-optimized contrast using different flip angle evolution (SPACE) sequence often used for vessel wall imaging is less susceptible to susceptibility artifacts, since it is a spin-echo sequence. Hence, we evaluated the feasibility of black-blood magnetic resonance angiography generated from vessel wall imaging data obtained using the SPACE sequence in the depiction of stented arteries by comparing with three-dimensional time-of-flight magnetic resonance angiography and digital subtraction angiography. Methods Our study group comprised 11 consecutive patients. For both three-dimensional time-of-flight magnetic resonance angiography and black-blood magnetic resonance angiography, the contrast ratio obtained from the stented artery and the normal artery proximal to the stent were calculated. And the depiction of stented arteries was visually evaluated. Additionally, the relative diameter index obtained from the stented artery and the normal artery proximal to the stent were calculated for three-dimensional time-of-flight magnetic resonance angiography, black-blood magnetic resonance angiography and digital subtraction angiography. Results The contrast ratio of the stented artery was significantly lower than that of the normal artery on three-dimensional time-of-flight magnetic resonance angiography, but no significant difference was seen using black-blood magnetic resonance angiography. Regarding both the diameter index and the visual assessment score, black-blood magnetic resonance angiography was significantly better than three-dimensional time-of-flight magnetic resonance angiography. On black-blood magnetic resonance angiography, the diameter index was equal to that of digital subtraction angiography, and the flow signal was homogeneous and continuous in most the cases.

Vessel Wall Imaging of Intracranial Arteries: Fundamentals and Clinical Applications

“…As 3D-VWI using a variable flip angle is a spin echo-based sequence, it is less affected by the magnetic susceptibility artifact produced by the stent, thrombi in the stent can be visualized, 73 and the diameter of the stented artery can be evaluated more accurately. 74 In addition, by postprocessing via partial minimum intensity projection (MinIP) in the source data of 3D-VWI to create a BB-MRA, it becomes easier to visually evaluate the stent lumen, as can be seen in MIP images of 3D-TOF MRA. 74 …”

“… 74 In addition, by postprocessing via partial minimum intensity projection (MinIP) in the source data of 3D-VWI to create a BB-MRA, it becomes easier to visually evaluate the stent lumen, as can be seen in MIP images of 3D-TOF MRA. 74 …”