Super High Contrast USPIO-Enhanced Cerebrovascular Angiography Using Ultrashort Time-to-Echo MRI

Figure 5

The technique provides qualitatively and quantitatively different vascular images than blood pool GBCA imaging. (a) Quantitative Ultrashort Time-to-Echo Contrast-Enhanced MR angiography compared to gadolinium-based contrast-agent enhanced Magnetization Prepared RApid Gradient Echo (MPRAGE), presented in maximum intensity projections (MIPs) from different individuals. High SNR and broad suppression of background (tissue, fat, and skull) signals enable simple visualization of the intracranial vascular network. (b) To examine the intracranial vessels, postprocessing is required to strip the skull while preserving superior cortical vessels for Gd MPRAGE. (c) Focusing on a cutout section emphasizes the increased delineation of smaller vessels using QUTE-CE MRA. (d) Histograms of raw intensity values in the cropped brains for the two techniques. Histograms capture the order of magnitude difference between the vessels (V) and tissue (T) in the two techniques. (e) As the high QUTE-CE CNR results in vascular enhancement below the voxel size, changing the visible intensity threshold allows examining vasculature across sizes. This effect is not possible with standard blood pool Gd imaging. Note that the top of the skull is cropped from both images to enable visualization of the structures inside the head in the Gd MPRAGE scan.