MR imaging of the human hand and wrist at 7 T

The purpose of this study was to evaluate the feasibility, quality, and possible future implications of magnetic resonance imaging (MRI) of the human hand and wrist at 7 T. Images of the left hand of a healthy volunteer were acquired with a 7- and a 1.5-T whole body system and comparatively analyzed. Axial and coronal two-dimensional gradient echo (GRE) images with inflow saturation, coronal 3D GRE images, and time-of-flight angiographies were obtained without averaging. Image details were related to the complex hand anatomy. With the 7-T protocols established in this study, high-quality and high-resolution images of the hand and wrist were obtained. In the 2D GRE images at 7 T, small anatomical structures of the hand were depicted in vivo with superior detail and resolution, compared to 1.5 T and published studies at lower field strength. Signal-to-noise ratios (SNRs) were approximately five times higher at 7 T compared to 1.5 T. Additionally, thin 3D GRE images with good quality of the whole hand were obtained in a short acquisition time. Moreover, time-of-flight angiographies of the small hand arteries have been acquired without the application of contrast agents. Seven-tesla imaging of the hand can be used in vivo with ultra-high resolution and sufficient SNR. It allows for exact delineation of most anatomical structures including nerves, muscles, tendons, ligaments, cartilage, and blood vessels.