Intracranial vessel wall MRI: a review of current indications and future applications

Abstract

Background: Intracranial vessel wall MRI (IVWM) is a new diagnostic imaging approach with the goal of evaluating intracranial vascular pathology by directly visualizing arterial vessel wall abnormalities with MR sequences, preferably at 3 Tesla field strength, that suppress blood and have excellent spatial resolution. Body: The differentiation of intracranial vascular pathology has historically relied on luminal imaging techniques that depict the alteration of flow created by atherosclerotic stenosis or vasospasm. With IVWM, it is possible to identify distinct radiologic findings of the pathology within the intracranial vessel wall itself, ranging from arterial dissection to vasculitis. Futhermore, IVWM imaging characteristics, such as post-contrast enhancement, can elucidate the temporal relationship between imaging findings and clinical pathology; and may predict future behavior of unruptured aneurysms or atherosclerotic plaques. Conclusion: We present a review of the basic IVWM imaging techniques and the relevant published literature on IVWM, with a focus on evidence-based diagnostic indications for IVWM and discussion of the strengths and weaknesses of each indication. Finally, we discuss how IVWM can be used to differentiate between intracranial pathology and future directions for IVWM research.

Circumferential Thick Enhancement at Vessel Wall MRI Has High Specificity for Intracranial Aneurysm Instability

“…Examinations were performed by using a 3-T MR imager (MR 750; GE Healthcare, Milwaukee, Wis) with an eight-channel head coil. The imaging protocol included at least a three-dimensional T1-weighted fast-spin-echo sequence (Cube; GE Healthcare), a three-dimensional variable refocusing flip angle acquisition with inherent black-blood effect, and post-contrast agent enhancement that enabled visualization of vessel wall enhancement (8,(11)(12)(13)(14). Technical parameters were as follows: field of view, 23 3 23 3 16 cm 3 ; repetition time msec/echo time msec, 600/11.5; bandwidth, 62.5 kHz; 288 3 288 3 160 matrix interpolated to 512 3 512 3 320 matrix; spatial resolution, 0.9 3 0.9 3 1 mm interpolated to 0.45 3 0.45 3 0.5 mm; and parallel acceleration was applied along the phase direction (autocalibrating reconstruction for Cartesian sampling, factor of two).…”

The Use and Pitfalls of Intracranial Vessel Wall Imaging: How We Do It

“…Although intracranial VW imaging is still in its developmental stage, there are already several challenging diagnostic situations in which it has shown its potential value (1,2,60,61), the most important of which is determining the cause of stroke and assessing accompanying VW lesions. Recently, two excellent review papers have been published that both address the commonly found imaging characteristics of different types of intracranial VW disease, including a thorough literature overview (2,62).…”

Advanced imaging in acute ischemic stroke

“…[1][2][3][4][5]. 9 This can provide a wealth of new information that timeof-flight (TOF) MRI sequences and other luminal imaging techniques cannot deliver.…”

“…9 To help provide a more accurate assessment of VW pathology, multiplanar 2D and 3D techniques are employed, and multiple sequences have been developed for this specific purpose. Fortunately, the acquisition of sequences for VW imaging does not significantly increase the time required to perform scanning, with some sequences adding only 7-11 minutes.…”

“…9 However, VW-MRI is helping to make diagnosis easier by detecting the VW enhancement that is nearly universally present in this condition. This enhancement is a result of the mural inflammation that is a hallmark of this disease process.…”