Assessment of short TI inversion recovery (STIR) imaging of soft tissue in the maxillofacial region

The purpose of this study was to describe short TI inversion recovery (STIR) signal characteristics of normal structures in the maxillofacial region, and evaluate the usefulness of the STIR imaging in the maxillofacial region compared with conventional T1- and T2-weighted spin echo (SE) images. Signal characteristics of normal structures (parotid glands, submandibular glands, sublingual glands, masseter muscles, lymph nodes, palatine tonsils, laryngeal tonsils, mandibular bone marrow) on STIR images in 80 normal subjects were evaluated. Lesion visibility on STIR images in 40 patients with histopathologically confirmed disorders (16 tumors, 2 malignant tumors, 10 cysts, 12 inflammations) in the maxillofacial region were compared with that on conventional T1- and T2-weighted SE images. Lesion visibility was rated as 1 (poor), 2 (moderate), 3 (good), 4 (excellent). On STIR imaging of normal subjects, parotid glands demonstrated intermediate signal intensities (77.5%), submandibular glands demonstrated intermediate to high signal intensities (95%) and sublingual glands demonstrated intermediate to high signal intensities (100%). Masseter muscles showed intermediate signal intensities (100%) and lymph nodes showed high signal intensities (100%) on STIR images. Palatine tonsils demonstrated intermediate to high signal intensities (81.25%) and the laryngeal tonsils demonstrated intermediate to high signal intensities (88.75%) on STIR images. Mandibular bone marrow demonstrated low signal intensities (83%) on STIR images. STIR imaging is more effective for evaluation in 40 disorders (16 tumors, 2 malignant tumors, 10 cysts 12 inflammations) than T1-weighted images and T2-weighted images especially in the case of inflammation (p<0.05). The use of STIR imaging is effective for diagnosing disorders in the maxillofacial region. (author)