Evaluation of the Articular Disc Using the Magnetic Resonance Cartigram in Asymptomatic and Symptomatic Temporomandibular Disorders.

The study is aimed to perform magnetic resonance (MR) cartigram of the articular disc in patients with asymptomatic and symptomatic temporomandibular disorders (TMD).  Thirty-nine volunteers were divided into three groups: 16 symptomatic TMD, 16 asymptomatic TMD, and 7 controls. The articular disc was divided into three segments (anterior, middle, and posterior) and analyzed using morphological magnetic resonance imaging (MRI) and T2 mapping sequences. T2 relaxation values were measured and assessed by an experienced radiologist and two observers. The T2 values in the discs were compared between the control, asymptomatic, and symptomatic groups using the Kruskal-Wallis test. The right and left discs were compared using the Wilcoxon signed rank test. Inter-examiner reliability among different examiners was evaluated.  The controls had the highest T2 values compared with the other groups. The comparison among the right and left sides of all the groups revealed statistically significant results in the anterior portion in the asymptomatic group and the middle portion in the symptomatic group (  < 0.05). The inter-examiner reliability coefficients among the three examiners were consistently high, with values of 0.921, 0.920, and 0.930.  Our study found the T2 relaxation time span was shorter than that reported in previous studies, which could be attributed to the early stage of cartilage deterioration in the individuals with TMD inferring treatment at this phase may be eventually effective with a good prognosis.