Status of growth plates can be monitored by MRI

Abstract

Background: Growth plate injuries and disorders cause premature closure, resulting in shortened or deformed limbs. Quantitative assessment by MRI might monitor the status of the growth plate and may assist in the prediction of these deformations.

Purpose: To investigate whether the status of the growth plate can be monitored by quantitative evaluation using MRI of the noninjured region of the growth plate in a physeal injury model.

Study type: Prospective, longitudinal.

Animal model: A 3.0-mm drill was used to create an injury to the central region of the right proximal tibial growth plate in 5-week-old male Japanese white rabbits (N = 18). The left tibia served as the control.

Field strength/sequence: 7.04T, T₂ -weighted imaging, diffusion-weighted imaging.

Assessment: Eight of 18 rabbits underwent MRI, proton density-weighted imaging, and T₂ -weighted and diffusion-weighted imaging. T₂ and apparent diffusion coefficient (ADC) maps were generated for each image. The growth plate height and the T₂ and ADC values of the noninjured region were measured. Two rabbits were sacrificed at 2, 4, 6, 8, and 10 weeks postinjury. Proximal tibial bones were evaluated using microcomputed tomography, histological, and immunohistological methods.

Statistical tests: Data were compared using repeated-measures analysis of variance followed by Tukey post-hoc multiple comparison.

Results: Growth plate height decreased at 10 weeks postinjury (P = 0.018) on the injured side. T₂ values were greater at 2 weeks postinjury (P = 0.0478) and decreased at 8 and 10 weeks (P = 0.0226, P = 0.0470, respectively) on the injured side. ADC values increased at 6 weeks on the lateral side (P = 0.0304) and decreased at 8 weeks and 10 weeks postinjury (P < 0.01) on the medial and injured sides, respectively.

Data conclusion: Quantitative MRI can help monitor the status of the growth plate and capture its changes early.

Level of evidence: 1 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2020;51:133-143.

Keywords: T2 map; diffusion-weighted image; growth disturbance; growth plate injury (physeal injury); growth plates (physis); magnetic resonance imaging (MRI).