Key clinical benefits of neuroimaging at 7 T

Abstract

The growing interest in ultra-high field MRI, with more than 35.000 MR examinations already performed at 7 T, is related to improved clinical results with regard to morphological as well as functional and metabolic capabilities. Since the signal-to-noise ratio increases with the field strength of the MR scanner, the most evident application at 7 T is to gain higher spatial resolution in the brain compared to 3 T. Of specific clinical interest for neuro applications is the cerebral cortex at 7 T, for the detection of changes in cortical structure, like the visualization of cortical microinfarcts and cortical plaques in Multiple Sclerosis. In imaging of the hippocampus, even subfields of the internal hippocampal anatomy and pathology may be visualized with excellent spatial resolution. Using Susceptibility Weighted Imaging, the plaque-vessel relationship and iron accumulations in Multiple Sclerosis can be visualized, which may provide a prognostic factor of disease. Vascular imaging is a highly promising field for 7 T which is dealt with in a separate dedicated article in this special issue. The static and dynamic blood oxygenation level-dependent contrast also increases with the field strength, which significantly improves the accuracy of pre-surgical evaluation of vital brain areas before tumor removal. Improvement in acquisition and hardware technology have also resulted in an increasing number of MR spectroscopic imaging studies in patients at 7 T. More recent parallel imaging and short-TR acquisition approaches have overcome the limitations of scan time and spatial resolution, thereby allowing imaging matrix sizes of up to 128×128. The benefits of these acquisition approaches for investigation of brain tumors and Multiple Sclerosis have been shown recently. Together, these possibilities demonstrate the feasibility and advantages of conducting routine diagnostic imaging and clinical research at 7 T.

The pulvinar nucleus and antidepressant treatment: dynamic modeling of antidepressant response and remission with ultra-high field functional MRI

“…Moreover, these studies differ in regard to the field strengths used, treatment regimens, and comparison groups. Even though 7 T might exhibit superiority for fMRIstatistics for most of the brain regions [11] and provide increased spatial specificity [18], this study in concert with Fig. 4 Non-remitter failed to upregulate temporoparietal junction after treatment .…”

Quantitative MRI of Perivascular Spaces at 3T for Early Diagnosis of Mild Cognitive Impairment

“…Compared to 7T EPVS MR imaging, the lower magnetic field strength of these scanners entails a lower detection sensitivity and a reduced signal to noise ratio. 29 However, it carries the benefit of a more homogenous radiofrequency B 1 field, a feature that is appreciated for segmenting EPVS based on pixel-wise spatial gradient. Most importantly, EPVS quantification from clinically accessible 3T MRI has a higher potential for clinical applications.…”

Over‐discretized SENSE reconstruction and B0 correction for accelerated non‐lipid‐suppressed 1H FID MRSI of the human brain at 9.4 T

“…In fact, the SNR has been shown to increase at a super‐linear rate with respect to the field strength . For magnetic resonance spectroscopic imaging (MRSI), the use of higher field strength can lead to images with higher spatial resolution and spectra with higher spectral resolution …”