Intracranial Artery Steno-Occlusion: Diagnosis by Using Two-dimensional Spatially Selective Radiofrequency Excitation Pulse MR Imaging

Purpose: To determine whether magnetic resonance (MR) imaging by using two-dimensional spatially selective radiofrequency (RF) excitation pulses (zoomed MR imaging) is a reliable method for the diagnosis of intracranial artery steno-occlusion compared with full-field-of-view (FOV) MR imaging. Materials and Methods: The institutional review board approved this retrospective study and informed consent was waived. From December 2014 to August 2015, 88 patients who underwent both fullFOV MR imaging and zoomed MR imaging for further evaluation of intracranial artery steno-occlusion at prior luminal evaluation were included. Two neuroradiologists independently diagnosed the diseases (atherosclerosis, dissection, moyamoya disease, vasculitis, undetermined diagnosis, and no vascular pathologic condition) based on both clinical information and MR imaging features and assessed diagnosisrelated parameters (diameter, length, eccentricity index, eccentricity, signal intensity ratio, vessel wall hemorrhage, and the total number of lesions), as well as image quality parameters (signal-to-noise ratio and image quality scale) with full-FOV MR imaging and zoomed MR imaging. Parametric measurements were compared between full-FOV MR imaging and zoomed MR imaging by using paired t test and McNemar test. The criterion for intermethod reliability was that the upper limit of the 95% confidence interval (CI) in the difference of agreement was less than 10% based on a noninferiority test. Results: The pooled agreement for diagnosing the disease between full-FOV MR imaging and zoomed MR imaging was 93% (164 of 176 lesions). The difference of agreement was 2.84% (one-sided 95% CI: 20.49%, 6.17%). The diagnosis-related parameters were not significantly different between both methods (all P>.05), with good to excellent agreement (both intraclass correlation coefficient and k value. 0.61). However, full-FOV MR imaging had better image quality parameters than zoomed MR imaging, including precontrast signal-to-noise ratio and image quality scale (both P>.05). Conclusion: Zoomed MR imaging is a reliable method for the diagnosis of intracranial artery steno-occlusion compared with full-FOV MR imaging. (C) RSNA, 2017