Longitudinal In Vivo 3T MRI of Naturally Occurring Early Osteochondrosis Lesions in the Piglet Humeral Epiphyseal Cartilage and Growth Plate

Osteochondrosis/osteochondritis dissecans (OC/OCD) is a developmental orthopedic disease primarily affecting the knee, ankle, and elbow joints of children and multiple animal species. Subclinical lesions of OC/OCD have been described, but most can be visualized only histologically in cadaveric specimens. To monitor the evolution of these lesions and to allow early separation of lesions that will undergo spontaneous healing versus requiring surgical intervention, Magnetic resonance imaging (MRI) techniques that are precise and can be used in vivo are needed. The purpose of this study was to demonstrate the utility of noninvasive 3 T MRI in the identification of naturally occurring OC lesions in the articular epiphyseal cartilage complex (AECC) and growth plate of the distal humerus in domestic piglets. N = 4 asymptomatic piglets underwent four consecutive, in vivo, bilateral elbow joint MRI exams under anesthesia at 4, 6, 8, and 11 weeks of age. 3D Double echo steady state (DESS) morphological images and cartilage T2 relaxation time maps were acquired using a clinical 3 T MRI scanner. After the last MRI, piglets were euthanized, and distal humeri were harvested for histologic evaluation. Multiple preclinical OC lesions were detected in the AECC and the growth plate of the examined humeri and their temporal progression or resolution was successfully monitored using MRI. Although most lesions resolved by 11 weeks of age, those remaining on MRI were confirmed histologically at necropsy. Clinical Significance: In vivo 3 T MRI may allow for longitudinal monitoring of early OC lesions and determination of whether a lesion is resolving or progressing to clinical OCD that may necessitate surgical intervention.