Incidental findings on preoperative head and neck MRI for orthognathic surgery in jaw deformity patients

Objective: Imaging is a critical component of orthognathic treatment. Magnetic resonance imaging (MRI) is a non-invasive method for observing the temporomandibular joint (TMJ). At our institution, MR images of the TMJ are also used when planning treatment for jaw deformities, head and neck screening images are also acquired using a head coil during MR imaging of the TMJ to confirm the presence of incidental findings (IFs) of head and neck lesions. IFs may require additional examination and/or treatment, even if the lesion is asymptomatic. This article presents a review of diseases detected as IFs during MR imaging. Case reports are also presented in which the detection of an IF affected the management of the jaw deformity.Methods: Reports of 401 patients with jaw deformities who underwent TMJ MR imaging including head and neck screening before preoperative orthodontic treatment were retrospectively reviewed.Results: Asymptomatic IFs were detected in 89 patients on screening images performed simultaneously with the TMJ MR imaging. The most common site was the maxillary sinus, and the most common lesions were inflammatory lesions. Although most of the IFs were not clinically significant, 10 required treatment prior to orthognathic treatment or required more detailed examination.Conclusions: Although small in number, some of the IFs detected in this study required the use of non-conventional treatment strategies. Our approach of combining TMJ MR imaging with head and neck screening assists not only in evaluating the TMJ but also in detecting lesions that are difficult to detect in radiographic images.