The T1 mapping and T2 mapping of lateral pterygoid muscle: a quantitative analysis in patients with acute and chronic temporomandibular joint disorders.

OBJECTIVE

The study aimed to quantitatively assess the signal changes in the lateral pterygoid muscle (LPM) of patients with acute and chronic temporomandibular joint disorders (TMD) using T1 mapping and T2 mapping techniques, and to explore the correlation between these changes and clinical symptoms.

MATERIALS AND METHODS

Fifty-five acute TMD patients, 121 chronic TMD patients, and 19 normal controls (NC) were enrolled in this prospective study. T1 mapping and T2 mapping sequences were acquired to obtain T1 and T2 values of the superior heads of the lateral pterygoid muscle (SHLP) and inferior heads of the lateral pterygoid muscle (IHLP). According to the position of the TMD, acute and chronic TMD patients were further divided into two subgroups, which were the normal position group (TMD-NP) and the anterior disc displacement group (TMD-ADD).

RESULTS

Chronic TMD patients exhibited significantly lower T1 mapping values in both SHLP and IHLP compared to NC and acute TMD patients (p < 0.05). Conversely, acute TMD-ADD patients showed significantly higher T2 mapping values in SHLP and IHLP compared to acute TMD-NP and NC (p < 0.05). Positive correlation was observed between T2 mapping values and numerical rating scale (NRS) scores for pain in both acute and chronic TMD patients (p < 0.05).

CONCLUSION

Chronic TMD may be associated with fat infiltration in the LPM, while acute TMD-ADD may present with inflammatory edema. The strong correlation between T2 mapping values and pain scores underscores the clinical utility of these techniques in assessing TMD severity and monitoring treatment responses.

KEY POINTS

Question Are there differences in T1 and T2 mapping signals of the LPMs between patients with acute and chronic TMD? Findings Chronic TMD patients had lower T1 mapping values, and cut TMD-ADD patients had higher T2 mapping values than acute TMD-NP and NC. Clinical relevance By providing quantitative measures of muscle signal changes, T1 mapping and T2 mapping may help clinicians differentiate between acute and chronic TMD, assess the severity of muscle involvement, and guide treatment decisions.