gms | German Medical Science

Objective: Magnetic resonance imaging (MRI) plays a major role in diagnosis, multimodal treatment, and follow-up of low-grade and high-grade gliomas. This study aims to prospectively evaluate low-grade and high-grade gliomas using 7 Tesla (T) MRI in comparison to the current 3 T MRI gold standard.

Method: Nineteen patients suffering from low-grade and high-grade gliomas underwent preoperative MRI scans at 3 T and 7 T, respectively. The local university institutional review board approved the study, and written informed consent was obtained before each examination. Acquired imaging sequences included pre- and post-contrast T1 weighted magnetization-prepared rapid acquisition gradient-echo, susceptibility weighted imaging (SWI), T2-weighted gradient echo, and T2-weighted fluid-attenuated inversion recovery (FLAIR). Images were evaluated in consensus reading by two experienced raters with special focus on intra-tumoral structures, vascularization, intra-lesional hemorrhage, and contrast uptake. The findings were correlated with histopathological gradings.

Results: All patients tolerated the examinations well and without report of any adverse effects. The study group comprised of 10 male and 9 female patients with a mean age of 50 years (23 – 82 years). Tumors were located in various brain regions: frontal (n=8), fronto temporal (n=2), temporal (n=6), parietal (n=1), occipital (n=1), and infiltrating the corpus callosum (n=1). Histological diagnoses included: glioblastoma multiforme (WHO IV, n=7), anaplastic astrocytoma (WHO III, n=6), anaplastic oligoastrocytoma (WHO III, n=2), oligoastrocytoma (WHO II, n=2), fibrillary astrocytoma (WHO II, n=1), and gliosarcoma (WHO IV, n=1). Intra-tumoral structures could be better visualized at 7 T compared to 3 T due to better image contrast and higher spatial resolution. Malignant gliomas showed micro hemorrhages and sub-millimeter vascularization in ultra-high-resolution SWI at 7 T, only vaguely delineated at 3 T. Depiction of tumor necrosis and perifocal edema was excellent in T2 and T2 FLAIR images.

Conclusions: Ultra-high-field 7 T MRI can depict intra-tumoral structures in excellent image quality superior to 3 T MRI. Further evaluation, especially of SWI in high-grade gliomas is warranted, as it might be a future imaging predictor for the course of the disease.