Evaluating MRI as a technique for visualizing the neurocentral junction

Study Design. Magnetic resonance imaging (MRI) of the neurocentral junction (NCJ) was correlated with gross anatomic and histologic sections acquired at the same position. Objectives. To determine the composition of the MRI of the NCJ and to explore the long-standing discrepancy between the ages of closure of the NCJ as determined by anatomic and imaging studies. Summary of Background Data. Disparate growth at the site of the NCJ has been implicated as a potential cause of adolescent idiopathic scoliosis since the early 1990s. Although anatomic studies have refuted this theory by maintaining that the NCJ closes before the age of 10 years, recent MRI studies have suggested that the NCJ remains open until adolescence. Methods. One hundred fourteen porcine NCJs in various stages of development were visualized using MRI. Gross anatomic and histologic sections were acquired at the same position as MRI for correlation. Results. The presence or absence of NCJ cartilage was represented by the presence or absence of a line on MRI. However, the NCJ image overestimated the width of the NCJ cartilage in the anteroposterior direction during development. As the NCJ underwent the process of closure, the NCJ image underestimated the extent of closure in the medial-lateral direction. Conclusions. Although MRI underestimated the extent of NCJ closure, MRI accurately showed whether cartilage was present or absent at the NCJ site. MRI determination of the age of NCJ closure appears reliable, and further exploration of the asymmetric growth hypothesis is required.