The increased field in the basal ganglia and correlation with disease duration suggest pathological iron content increases in MS. The peripheral phase rings are consistent with histological data demonstrating iron-rich macrophages at the periphery of a subset of lesions. The clearly defined vessels penetrating MS lesions should increase our ability to detect focal vascular abnormalities specifically related to demyelinating processes.

The increased susceptibility effects and high signal-to-noise ratio at 7T enable imaging of the brain using the phase of the magnetic resonance signal. This study describes and evaluates a robust method for calculating phase images from gradient-recalled echo (GRE) scans. The GRE scans were acquired at 7T using an eight-channel receive coil at spatial resolutions up to 0.195×0.260×2.00mm. The entire 7T protocol took less than 10 minutes. Data was acquired from forty-seven subjects including clinical patients with multiple sclerosis (MS) or brain tumors. The phase images were post-processed using a fully automated phase unwrapping algorithm that combined the data from the different channels. The technique was used to create the first phase images of MS patients at any field strength and the first phase images of brain tumor patients above 1.5T. The clinical images showed novel contrast in MS plaques and depicted microhemorrhages and abnormal vasculature in brain tumors with unsurpassed resolution and contrast.

Susceptibility-weighted imaging (SWI) is a valuable technique for high-resolution imaging of brain vasculature that greatly benefits from the emergence higher field strength MR scanners. Autocalibrating partially parallel imaging techniques can be employed to reduce lengthy acquisition times as long as the decrease in signal-to-noise ratio does not significantly affect the contrast between vessels and brain parenchyma. This study assessed the feasibility of a GRAPPA-based SWI technique at 7 Tesla in both healthy volunteers and brain tumor patients. GRAPPA-based SWI allowed a 2-fold or more reduction in scan time without compromising vessel contrast and small vessel detection. Post-processing parameters for the SWI needed to be modified for patients where the tumor causes high-frequency phase wrap artifacts but did not adversely affect vessel contrast. GRAPPA-based SWI at 7T revealed regions of microvascularity, hemorrhage, and calcification within heterogeneous brain tumors that may aid in characterizing active or necrotic tumor and monitoring treatment effects.