Validation of Zero TE–MRA in the Characterization of Cerebrovascular Diseases: A Feasibility Study

Abstract

BACKGROUND AND PURPOSE: Zero TE-MRA is less sensitive to field heterogeneity, complex flow, and acquisition noise. This study aimed to prospectively validate the feasibility of zero TE-MRA for cerebrovascular diseases assessment, compared with TOF-MRA. MATERIALS AND METHODS: Seventy patients suspected of having cerebrovascular disorders were recruited. Sound levels were estimated for each MRA subjectively and objectively in different modes. MRA image quality was estimated by 2 neuroradiologists. The degree of stenosis (grades 0-4) and the z-diameter of aneurysms (tiny group Յ3 mm and large group Ͼ3 mm) were measured for further quantitative analysis. CTA was used as the criterion standard. RESULTS: Zero TE-MRA achieved significantly lower subjective perception and objective noise reduction (37.53%). Zero TE-MRA images showed higher signal homogeneity (3.29 Ϯ 0.59 versus 3.04 Ϯ 0.43) and quality of venous signal suppression (3.67 Ϯ 0.47 versus 2.75 Ϯ 0.46). The intermodality agreement was higher for zero TE-MRA than for TOF-MRA (zero TE, 0.90; TOF, 0.81) in the grading of stenosis. Zero TE-MRA had a higher correlation than TOF-MRA (zero TE, 0.84; TOF, 0.74) in the tiny group and a higher consistency with CTA (intraclass correlation coefficient, 0.83; intercept, Ϫ0.5084-1.1794; slope Ϫ0.4952 to Ϫ0.2093) than TOF-MRA (intraclass correlation coefficient, 0.64; intercept, 0.7000-2.6133; slope Ϫ1.0344 to Ϫ0.1923). Zero TE-MRA and TOF-MRA were comparable in the large group. Zero TE-MRA had more accurate details than TOF-MRA of AVM and Moyamoya lesions. CONCLUSIONS: Compared with TOF-MRA, zero TE-MRA achieved more robust performance in depicting cerebrovascular diseases. Therefore, zero TE-MRA was shown to be a promising MRA technique for further routine application in the clinic in patients with cerebrovascular diseases. ABBREVIATIONS: ASL ϭ arterial spin-labeling; AVM ϭ arteriovenous malformation; MRA ϭ magnetic resonance angiography; CTA ϭ computed tomography angiography; CE ϭ contrast-enhanced; TOF ϭ time-of-flight; zTE ϭ zero echo time; MIP ϭ maximum intensity projection; VR ϭ volume rendering; MCA ϭ middle cerebral artery; ICA ϭ internal carotid artery

The feasibility of non-contrast-enhanced zero echo time magnetic resonance angiography for characterization of intracranial atherosclerotic disease

“…Similar to previous reports (23,42), we also found that zTE-MRA resulted in lower quality imaging of distal small branched vessels than TOF-MRA (Figure 4). In essential, zTE-MRA is a continuous ASL-based angiography method (15).…”

“…With these advantages, zTE-MRA might be considered with added clinical value in diagnosis of ICAS. Notably, Shang et al (23) recently published an interesting study that also confirmed the clinical value of zTE-MRA for imaging cerebrovascular diseases. Compared with their study, we used DSA as the reference for ICAD diagnosis, which we believe is more accurate than the CTA applied in their investigation (40).…”

“…In addition, other scholars also employed zTE-MRA for evaluating cerebrovascular disorder in clinic, including cerebral arteriovenous malformation and moyamoya disease (20)(21)(22). In essence, zTE-MRA uses a continuous ASL strategy and a zTE radial acquisition readout scheme (23). Both these intrinsic properties separately facilitate the acquisition of MRA images, with inflowing blood labeled with an endogenous contrast agent, and with high signal-to-noise-ratio and less sensitivity to local field inhomogeneities.…”

Can Hybrid Arterial Spin Labeling‐Tagged Zero‐Echo‐Time Magnetic Resonance Angiography Be an Effective Candidate in the Evaluation of Intracranial Artery Diseases? A Clinical Feasibility Study

“…A previously reported 5‐point scale was applied 29 : 0 = no noise, 1 = mild noise, 2 = moderate noise, 3 = loud noise, 4 = very loud noise, and 5 = unacceptable noise/cancellation of MR imaging. Objective measurements were described in previous study 16 . Briefly, a sound‐level meter (Type AS804; Smart Sensor, Guangdong, China) was used to measure the sound intensity under ambient and scanning conditions.…”

“…Among the various ASL‐MRA approaches, zero‐echo‐time (ZTE) MRA can diminish the saturation effect, minimize magnetic susceptibility, and reduce acoustic noise by integrating a continuous ASL (cASL) strategy, ZTE acquisition, and three‐dimensional (3D) radial sampling trajectories 14 . Previous studies have demonstrated the promising superiority of cASL‐ZTE‐MRA over TOF‐MRA in the follow‐up assessment of coiled aneurysms and the diagnosis of intracranial artery diseases 15–20 . However, Holdsworth et al implied that marginal blurring along the vessel walls occurs in cASL‐ZTE‐MRA and might be mistaken for vascular lesions 21 .…”