Our latest manuscript on universal RF shimming for human head imaging at 10.5T! Very grateful to have collaborated on this project with Simon Schmidt, Greg Metzger, Wolfgang Bogner, and Gosia Marjanska. #MRI #UltraHighField #10_5T #Neuroimaging #UMN #CMRR
onlinelibrary.wiley.com/doi/10.1002/...
To date, 7T TOF-MRA has shown value in the evaluation of cerebrovascular malformations, atherosclerosis, and neurodegenerative diseases. However, it also faces challenges such as susceptibility artifacts at the air-bone interface of the sella turcica region, and physiological motion (e.g., vascular pulsation), which lead to suboptimal imaging of the petrous segment of the internal carotid artery (ICA). This paper aims to optimize imaging of the petrous ICA through optimized acquisition parameters. The petrous segment of the ICA is located in the parasellar region, where the large susceptibility difference between air and bone leads to susceptibility artifacts. These artifacts affect the homogeneity of both the B0 and B1 fields, which can result in asymmetry of TOF signals between the two sides. Even B0 shimming and volume-specific parallel-transmit (pTX) B1 shimming could not fully resolve the signal loss at the ICA. The optimization strategy was revised by altering the flow compensation scheme and increasing the acquisition bandwidth, therefore shortening the echo time (TE) and reducing the influence of T2* effects. Furthermore, changing the phase-encoding direction redirected pulsation artifacts away from critical vascular structures. Together, these approaches minimized the impact of susceptibility and pulsation artifacts in this region and led to a better display of the ICA on the TOF-MRA. The figures show a 77-year-old male with atherosclerosis. Visual inspection of the original TOF-MRA images revealed the following findings: 1. Shorter TE values exhibit superior efficacy in suppressing vascular pulsation artifacts. 2. Reduced TE improved homogeneity of the blood flow signal. 3. Under conditions of pronounced pulsation artifacts, P>>A (posterior-to-anterior) phase-encoding orientation effectively prevents cross-vessel interference induced by pulsation-related artifacts.
Optimization of Petrous Internal Carotid Artery Imaging in #7T Ultra-High-Field TOF-MRA by Hui Liu, Ph.D. (Siemens Healthineers, Zhengzhou, China).
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#MRI #NeuroSky #MRA #VesselImaging #UHF #UltraHighField
Among the various functional imaging techniques, arterial spin labeling (#ASL) has emerged as a powerful tool, not only in neuroscience and cognitive research but also in clinical practice. By using water as an endogenous tracer, ASL delivers quantitative perfusion information with high spatial specificity. Over the years, ASL has demonstrated its clinical value in diagnosing and monitoring a range of neurological conditions, from stroke and brain tumors to neurodegenerative disease, and has been extensively applied at 3T and 1.5T field strengths. The advent of ultra-high-field (UHF) 7T MRI has opened new opportunities for ASL while also presenting significant technical challenges. Increased magnetic field strength accentuates B0 and RF field inhomogeneities, increases SAR, and markedly reduces transverse relaxation time (T2). These challenges, less pronounced at 3T or lower fields, demand systematic innovations and modifications to the ASL sequence to ensure robust and reliable performance at 7T. The figure shows a 45-year-old woman with pathologically confirmed oligodendroglioma. A mass with predominantly mild heterogeneous hyperintensity on T2-weighted imaging was observed in the right frontal lobe, extending into the knee of the corpus callosum, with small areas of hypointensity. Susceptibility-weighted imaging (SWI) sequences revealed signs of bleeding or calcification within the mass, and significant enhancement was noted. ASL sequences demonstrated hyperperfusion in most regions of the lesion.
Unlocking the Potential of ASL at 7T #MRI: Overcoming Challenges and Advancing Neuroscience Applications
by Danny JJ Wang (@keck.usc.edu), @jianxun-qu.bsky.social (Siemens Healthineers), et al www.magnetomworld.siemens-healthineers.com/clinical-cor...
#NeuroSky #UltraHighField @mritobi.bsky.social
Ultra-high-field magnetic resonance imaging (UHF MRI) at 7T holds promise for tackling these obstacles, given its capacity to generate higher-resolution images and offer distinct contrasts due to a higher susceptibility effect and different relaxation time constants. GRE T2*-weighted imaging (T2*WI) is a fast, convenient, noninvasive, and feasible technique that exhibits advantages in clinical settings. T2*W sequences make it easier to identify lesions in the local magnetic field, such as bleeding and hemosiderin accumulation. Structures with slightly different magnetic properties introduce detectable field variations at high B0, which leads to a noticeable increase in lesion identification at 7T. Learn more about - SWI in Wilson disease - SWI in primary angiitis of the central nervous system - T2*-weighted MRI in multiple sclerosis - Other biomarkers such as motor band sign in amyotrophic lateral sclerosis (ALS) patients
Insights from 7T: GRE T2*-weighted Sequences Uncover Biomarkers in Neurological Diseases by Jing Jing, MD; et al (Tiantan Neuroimaging Center of Excellence, Beijing, China). Learn more at
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#MagnetomWorld #UltraHighField #7T #MRI #NeuroSky
