The MRI appearance of myloglossus.

PURPOSE: This case report describes the MRI appearance and significance of the myloglossus muscle, a variant extrinsic tongue muscle. METHODS: The myloglossus muscle was incidentally discovered on imaging performed for head and neck cancer evaluation. RESULTS: The myloglossus is best visualized on non-fat saturated T2 MRI and has signal characteristics that match those of muscle. It originates at the angle of the mandible and inserts into the tongue between the styloglossus and hyoglossus. CONCLUSION: Accurate identification and delineation of the extrinsic muscles of the tongue, including the myloglossus, is essential for proper staging and treatment of head and neck cancers. This case report attempts to fill a void in depicting the MRI appearance of myloglossus muscle.

Transverse growth of the mandibular body in untreated children: a longitudinal CBCT study.

OBJECTIVES: Currently available reports on mandibular transverse growth are limited to two-dimensional images and cross-sectional studies. The objective of this study was to examine transverse growth of the mandibular body in untreated growing individuals during the mixed dentition stage using longitudinal three-dimensional imaging. METHODS: CBCT images of 25 (13 females and 12 males) untreated subjects at two time points were analyzed. The average age was 9.1 years at T1 and 11.3 years at T2. Mandibular segmentation and superimposition were performed to obtain linear and angular measurements at different axial levels. RESULTS: At the superior (mental foramen) axial level, transverse growth between the buccal surfaces gradually increased from the premolars to the ramus. At the inferior axial level, significant transverse growth differences were detected between the ramus and the dentition regions. In contrast, between the lingual surfaces, both superior and inferior levels showed minimal change in the region under the dentition and a significant amount of resorption in the ramus region. This difference between buccal and lingual surface changes led to a mandibular body angulation change in the premolar and molar regions. In contrast, the overall mandibular body angulation measured from the posterior-most border of the mandible to the symphysis remained the same. Differences were detected between males and females, with males tending to exhibit greater transverse growth in the ramus region at the inferior level. CONCLUSIONS: The mandibular body exhibited different transverse growth patterns at different axial levels. Differences were also found between genders. CLINICAL RELEVANCE: An in-depth understanding of craniofacial growth and development is crucial to diagnosis and treatment planning. The current study provides additional insight into the transverse growth of the mandible.

The interplay among a dental procedure, infective endocarditis, and an acute ischemic stroke.

BACKGROUND: This case report highlights the rare association among a dental procedure, infective endocarditis, and an acute ischemic stroke. CASE DESCRIPTION: A 54-year-old woman who experienced an acute ischemic stroke 5 weeks after a tooth extraction is described. The initial symptoms of this patient included mild to moderate word-finding difficulty and right facial droop. Computed tomographic angiography revealed a left M1 segment middle cerebral artery occlusion (thrombolysis in cerebral infarction scale, 0) with reconstitution of the distal middle cerebral branches through arterial collaterals. After initial administration of tissue plasminogen activator, endovascular thrombectomy was successfully performed with thrombolysis in cerebral infarction scale 3 (complete) recanalization. After the procedure, the patient showed improvement in language and neurologic deficits. Imaging showed multifocal, bilateral, cortical, and deep brain hemorrhages. Blood cultures grew Streptococcus mitis, ultimately leading to the diagnosis of endocarditis. Echocardiographic imaging revealed moderate to severe aortic insufficiency, a mitral valve vegetation, and mild mitral valve regurgitation. After evaluation by the cardiothoracic surgery team, the patient was discharged with intravenous antibiotics and short-term outpatient follow-up with the cardiothoracic surgery team. PRACTICAL IMPLICATIONS: Dental procedures, although generally safe, can introduce oral bacteria into the bloodstream, leading to bacterial seeding of cardiac valves and subsequent infective endocarditis. Recognizing infective endocarditis subsequent to a dental procedure, including a tooth extraction, as a potential cause of an acute ischemic stroke is vital so that prompt treatment can be initiated.

A User-Friendly Protocol for Mandibular Segmentation of CBCT Images for Superimposition and Internal Structure Analysis.

BACKGROUND: Since cone-beam computed tomography (CBCT) technology has been widely adopted in orthodontics, multiple attempts have been made to devise techniques for mandibular segmentation and 3D superimposition. Unfortunately, as the software utilized in these methods are not specifically designed for orthodontics, complex procedures are often necessary to analyze each case. Thus, this study aimed to establish an orthodontist-friendly protocol for segmenting the mandible from CBCT images that maintains access to the internal anatomic structures. METHODS: The "sculpting tool" in the Dolphin 3D Imaging software was used for segmentation. The segmented mandible images were saved as STL files for volume matching in the 3D Slicer to validate the repeatability of the current protocol and were exported as DICOM files for internal structure analysis and voxel-based superimposition. RESULTS: The mandibles of all tested CBCT datasets were successfully segmented. The volume matching analysis showed high consistency between two independent segmentations for each mandible. The intraclass correlation coefficient (ICC) analysis on 20 additional CBCT mandibular segmentations further demonstrated the high consistency of the current protocol. Moreover, all of the anatomical structures for superimposition identified by the American Board of Orthodontics were found in the voxel-based superimposition, demonstrating the ability to conduct precise internal structure analyses with the segmented images. CONCLUSION: An efficient and precise protocol to segment the mandible while retaining access to the internal structures was developed on the basis of CBCT images.