MRI - Planes, parameters

Because of the large number of differently aligned structures in several anatomic regions, many dedicated MRI protocols must be used on the hand.

Standardized angulation of the imaging planes is important for comparability. They are planned using localizers (scouts), which are successively scanned perpendicular to each other in the three planes. Transaxial slices are acquired first. They are aligned perpendicular to the longitudinal axis of the forearm. This is followed by the coronal and sagittal planes, which in turn are perpendicular to each other.

Due to their anatomical orientation, the imaging planes for the SL and LT ligaments must be aligned obliquely, either primarily during acquisition or secondarily as part of reconstructions (MPR) of a 3D data set. Radial MPR slices with a pivot point on the ulnar styloid process are advantageous for visualizing the triangularly shaped TFCC. We recommend these as they significantly facilitate the diagnostics of TFCC lesions.

The finger rays converge on the carpal tunnel or scaphoid and are arranged in a transverse arch. In addition, the thumb ray is in opposition. The exact plane alignment can therefore only be performed on one finger ray simultaneously. Slice planning is done in the three orthogonal planes, aligning the respective finger skeleton and tendons in the transaxial plane.

Tags: Hand, Planes, Parameters, MRI