Development of Real-Time Kinematic Magnetic Resonance Imaging (kMRI) Techniques for Studying the Kinematics of the Spine and Joints in Dogs-Preliminary Study on Cadavers

Abstract

Kinematic MRI (kMRI) is a novel human imaging technique that couples the excellent soft tissue contrast and multiplanar capabilities of traditional MRI with kinematic potential. The study's goals are: (1) testing the feasibility of spinal cord and joints real-time kMRI; and (2) evaluating the quality of these kinematic studies as a new diagnostic option in veterinary medicine. Standard and real-time kinematic MRI were performed on cervical spine, elbow, and stifle joints of seven cadavers. Studies were repeated after a surgical insult aimed to create a certain degree of joint instability. A total of 56 MRI were performed-7 cervical spinal tracts, 3 elbow joints, and 4 stifle joints were examined. The technique was feasible in all the three regions examined. The images were considered of excellent quality for the stifle joint, good to fair for the cervical spine, whereas two of three elbow studies were considered to have unacceptable image quality. Additionally, real-time kMRI provided good to excellent information about stifle instability. Therefore we consider kMRI a promising technique in veterinary medicine. Further studies and an in vivo setting are needed to increase the quality of the kMRI images, and to fully evaluate clinical usefulness.

Keywords: canine; cervical spine; elbow; real-time kinematic MRI; stifle.

Figure 1

(A) Before, (B) during, and (C) after the ventral slot procedure to remove two intervertebral disks and the dorsal longitudinal ligament.

Figure 2

Mongrel, 7 years old, male entire (Case 4). Cervical spine MRI sample images. (A) T2 weighted mid-sagittal image of the cervical spine. (B) Real-time kMRI starting position, no spinal cord compression is visible. (C) Real-time kMRI during flexion movement, C4–C5 mild subluxation is evident (arrow).

Figure 3

Dobermann, 8 years old, male entire (Case 7). Cervical spine MRI sample images: (A) T2 weighted mid-sagittal image of the cervical spine. (B–E) Real-time kMRI during neck flexion, C4–C5 mild dynamic subluxation is visible (arrows).

Figure 4

Case 6 elbow k-MRI sample images. (A) Neutral starting position; (B) point of maximum flexion.

Figure 5

Case 6 stifle k-MRI sample images. (A) Starting position, normal femorotibial alignment. (B) TCT endpoint, cranial subluxation of the tibia is visible, due to surgical cranial cruciate ligament resection; (C) flexion and (D) extension movement, femorotibial, no subluxation visible.