Dynamic tracking of scaphoid, lunate, and capitate carpal bones using four-dimensional MRI

Abstract

A preliminary exploration of technical methodology for dynamic analysis of scaphoid, capitate, and lunate during unconstrained movements is performed in this study. A heavily accelerated and fat-saturated 3D Cartesian MRI acquisition was used to capture temporal frames of the unconstrained moving wrist of 5 healthy subjects. A slab-to-volume point-cloud based registration was then utilized to register the moving volumes to a high-resolution image volume collected at a neutral resting position. Comprehensive in-silico error analyses for different acquisition parameter settings were performed to evaluate the performance limits of several dynamic metrics derived from the registration parameters. Computational analysis suggested that sufficient volume coverage for the dynamic acquisitions was reached when collecting 12 slice-encodes at 2.5mm resolution, which yielded a temporal resolution of and 2.6 seconds per volumetric frame. These acquisition parameters resulted in total in-silico errors of 1.9°±1.8° and 3°±4.6° in derived principal rotation angles within ulnar-radial deviation and flexion-extension motion, respectively. Rotation components of the carpal bones in the radius coordinate system were calculated and found to be consistent with earlier 4D-CT studies. Temporal metric profiles derived from ulnar-radial deviation motion demonstrated better performance than those derived from flexion/extension movements. Future work will continue to explore the use of these methods in deriving more complex dynamic metrics and their application to subjects with symptomatic carpal dysfunction.

Wrist & Hand

“…Most previous published work has focused on technologies as they have developed, such as X-ray fluoroscopy and 4D CT scanning; however, the present study from Milwaukee (Wisconsin, USA) explored dynamic joint profiling using MRI. 1 The two main advantages of MRI are obviously that it is non-ionizing, but most importantly for the hand and wrist, that it also gives more information with respect to soft-tissues such as ligaments. The study sought to examine whether dynamic 4D MRI can be used to track rotational motion of the scaphoid, lunate, and capitate during unconstrained movements.…”

Real-time MRI of the moving wrist at 0.55 tesla

“…4 To address this shortcoming, realtime MRI (RT-MRI) protocols, typically using 1.5T and 3T MRI scanners, have been developed. [5][6][7] These protocols, however, have suffered from a relatively slow image acquisition rate that is inadequate for tracking wrist motion at natural speeds, and image artifacts that frequently obscure critical wrist structures.…”