Anna Louise Beattie MBBCh, BSc, Presenter: Nothing to Disclose

Gustav Andreisek MD, Abstract Co-Author: Nothing to Disclose

Lawrence M. White MD, Abstract Co-Author: Nothing to Disclose

Marshall Stephen Sussman PhD, Abstract Co-Author: Nothing to Disclose

A novel navigator-based MRI technique has been developed for visualizing joint kinematics. This technique potentially allows generation of kinematic images with high spatial and temporal resolution. Our aims were to demonstrate feasibility of the technique for visualizing joint kinematics, and to evaluate the influence of different temporal resolutions on image quality relative to conventional kinematic sequences.

14 healthy volunteers (male, 5; female, 9; mean age, 32.7) gave informed, written consent. Repetitive radio-ulnar deviation of the wrist was performed throughout the MR scan. The navigator-based technique was applied to fast imaging employing steady-state acquisitions (FIESTA) sequences (TR/TE, 4.3/1.9 msec) at 1.5T. Three navigator acquisitions with different temporal resolutions (34.4, 68.8, and 137.6 msec) were achieved by varying frequency of navigator lines. One conventional FIESTA sequence (temporal resolution, 1.1 sec) was performed for comparison. Reconstructed movie loops were qualitatively analyzed by two blinded observers and independently ranked with regard to “smoothness of motion”, “sharpness of anatomic borders”, and “presence of artifacts” using a 4-point rank scale. A randomization test was performed on ranked data. Inter-observer agreement was calculated using Cohen`s kappa.

The navigator-based kinematic method was technically successful in all subjects. Smoothest motion was observed at temporal resolutions of 34.4msec; (p=0.009) and was significantly better with the navigator than conventional technique. Temporal resolution greater than 34.4ms was associated with reduced image sharpness (p=0.008). Navigator acquisitions had more artefacts than images without (p=0.011). The overall inter-observer agreement was moderate (κ = 0.59).

Kinematic MRI of the wrist using navigator-based acquisitions is feasible and imaging with a temporal resolution of 34.4 msec shows smoothest representation of the joint motion.

Abnormal joint kinematics can predispose to osteoarthritis, therefore we aim to optimise non-invasive imaging with good spatial and temporal resolution and good soft tissue contrast.

Beattie, A, Andreisek, G, White, L, Sussman, M, Kinematic MRI of the Wrist Using Novel Similarity-based Navigator Echo (SIMNAV) Technique: Feasibility and Influence of Temporal Resolution on Image Quality.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6006511.html