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 ≤3 mm and large group >3 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 ± 0.59 versus 3.04 ± 0.43) and quality of venous signal suppression (3.67 ± 0.47 versus 2.75 ± 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, −0.5084–1.1794; slope −0.4952 to −0.2093) than TOF-MRA (intraclass correlation coefficient, 0.64; intercept, 0.7000–2.6133; slope −1.0344 to −0.1923). 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.
Gliomas constitute over 90% of primary brain tumors. Accurate identification of glioma recurrence and treatment effects is important, as it can help determine whether to continue with standard adjuvant chemotherapy or to switch to a second-line therapy for recurrence. Our purpose is to compare three dimensional pseudo-continuous arterial spin labeling (3D-pcASL) technique and dynamic susceptibility contrast perfusion magnetic resonance imaging (DSC-MRI) for differentiation tumor recurrence from treatment-related effects in gliomas.Twenty-nine patients with gliomas previously who showed enlarged, contrast-enhancing lesions within the radiation field after surgery and concurrent chemoradiotherapy (CCRT) were assessed with 3D-pcASL and DSC-MRI. These patients were classified into 2 groups, tumor recurrence group (n = 17) and treatment effects group (n = 12), based on pathologic analysis or clinical-radiologic follow-up. The perfusion imaging quality was assessed using a 3-point scale (1 = poor imaging, 2 = moderate imaging, and 3 = good imaging). Comparison for perfusion imaging-quality score between the 2 techniques was performed with Wilcoxon one-sample test. Quantitative analyses were performed between the 2 groups with cerebral blood flow values (ASL-CBF), relative cerebral blood flow values (ASL-rCBF, DSC-rCBF), and relative cerebral blood volume values (DSC-rCBV) using Wilcoxon one-sample test. The intra-class correlation coefficient (ICC) statistics were calculated for testing intrareader variability in regions of interest (ROIs) measurement of all perfusion parameters.The imaging-quality score of 3D-pcASL was higher than that of DSC-MRI (P = .01). The perfusion parameters between tumor recurrence group and treatment effects group had statistically significant differences. There was a significant correlation between ASL-rCBF and DSC-rCBF values (r = 0.803), between ASL-rCBF and DSC-rCBV values (r = 0.763), and between DSC-rCBF and DSC-rCBV (r = 0.907). A receiver operating characteristic (ROC) curve analysis was performed for significant results of perfusion parameters between the 2 groups. Using a cutoff value of 1.110, ASL-rCBF showed the maximum area under the ROC curve (AUC). However, there were no significant differences among different AUCs. The ICC demonstrated excellent agreement for ROIs measurements of ASL-CBF (ICC = 0.9636), dynamic susceptibility contrast- cerebral blood flow (DSC-CBF) (ICC = 0.8508), and dynamic susceptibility contrast-cerebral blood volume (DSC-CBV) (ICC = 0.8543).3D-pcASL is an alternative perfusion method to DSC-MRI for the differentiation between tumor recurrence and treatment effects in gliomas. 3D-pcASL is noninvasive and shows fewer susceptibility artifacts than DSC-MRI.
This study used blood oxygen level-dependent (BOLD) MRI to assess the hemodynamics of the lower limbs for patients with peripheral artery disease. We obtained dynamic change of BOLD T2* with high temporal and spatial resolution in reactive hyperemia experiment and found good correlation between BOLD parameters and clinical walking performance, which verified the significance of perfusion measurement for clinical assessment.
Motivation: Lower extremity reactive hyperemia BOLD have been used to evaluate the skeletal muscle perfusion status. The existing methods, such as multi-echo GRE and single-echo EPI, have limitations in terms of spatial coverage and signal quantification. Goal(s): The study aims to apply dual-echo multi-band EPI to achieve high temporal and spatial resolution, and large coverage in BOLD experiment. Approach: The study applied dual-echo EPI to sample the T2* along the reactive hyperemia experiment. Images at TE of zero were synthesized to investigate the intrinsic signal change. Results: The proposed method can provide semi-quantitative indicators of the perfusion status of the lower extremity skeletal muscle. Impact: This work demonstrates the advantages of dual echo EPI acquisition for lower extremity reactive hyperemia experiments. Compared to the commonly used acquisition strategies, the proposed one can be used to enhance the quality and efficiency of lower extremity perfusion imaging.
The authors conducted a study to noninvasively and nonradioactively reveal moyamoya disease (MMD) intracerebral perfusion and perfusion territory supplied by the unilateral internal carotid artery (ICA) and external carotid artery (ECA) and bilateral vertebral arteries (VAs) before surgery and to further identify risk factors for preoperative hemorrhage in adult MMD.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)