Factors influencing the accuracy of multimodal image fusion for oral and maxillofacial tumors: a retrospective study.

BACKGROUND: Ensuring high accuracy in multimodal image fusion for oral and maxillofacial tumors is crucial before further application. The aim of this study was to explore the factors influencing the accuracy of multimodal image fusion for oral and maxillofacial tumors. METHODS: Pairs of single-modality images were obtained from oral and maxillofacial tumor patients, and were fused using a proprietary navigation system by using three algorithms (automatic fusion, manual fusion, and registration point-based fusion). Fusion accuracy was evaluated including two aspects-overall fusion accuracy and tumor volume fusion accuracy-and were indicated by mean deviation and fusion index, respectively. Image modality, fusion algorithm, and other characteristics of multimodal images that may have potential influence on fusion accuracy were recorded. Univariate and multivariate analysis were used to identify relevant affecting factors. RESULTS: Ninety-three multimodal images were generated by fusing 31 pairs of single-modality images. The interaction effect of image modality and fusion algorithm (P = 0.02, P = 0.003) and thinner slice thickness (P = 0.006) were shown to significantly influence the overall fusion accuracy. The tumor volume (P < 0.001), tumor location (P = 0.007), and image modality (P = 0.01) were significant influencing factors for tumor volume fusion accuracy. CONCLUSIONS: To ensure high overall fusion accuracy, manual fusion was not preferred in CT/MRI image fusion, and neither was automatic fusion in image fusion containing PET modality. Using image sets with thinner slice thickness could increase overall fusion accuracy. CT/MRI fusion yielded higher tumor volume fusion accuracy than fusion containing PET modality. The tumor volume fusion accuracy should be taken into consideration during image fusion when the tumor volume is small and the tumor is located in the mandible.

Expressions of GLUT-1, PK-M2 and HIF-1α and Mutation Status of BRAF in Odontogenic Keratocysts.

OBJECTIVE: To investigate the expressions and clinicopathological features of glucose transporter 1 (GLUT-1), pyruvate kinase M2 (PK-M2) and hypoxia-inducible factor 1α (HIF-1α) in odontogenic keratocysts (OKCs), and to investigate the mutation status of v-raf murine sarcoma viral oncogene homolog B1 (BRAF). METHODS: Following a retrospective review of the clinicopathological data of 28 OKC cases, the expressions of GLUT-1, PK-M2 and HIF-1α in these tissue samples were detected through immunohistochemistry. The BRAF mutation statuses of all cases were examined using polymerase chain reaction amplification and direct sequencing. RESULTS: The expression levels of HIF-1α varied in 96.4% of OKC tissues, and there were higher positive rates of PKM2 (100%) and GLUT-1 (100%) in these tissues. None of the 28 OKC samples carried the BRAF mutation. CONCLUSION: The positive expressions of GLUT-1, PK-M2 and HIF-1α indicate that patients with OKCs undergo anaerobic glycolysis to a certain extent, but these processes appear to be irrelevant to clinicopathological features and to the BRAF mutation.

[Temporomandibular joint osteoarthrosis in patients receiving orthodontic treatments: a clinical investigation].

OBJECTIVE: To investigate the clinical characteristics of temporomandibular joint osteoarthrosis (TMJOA) in patients with malocclusion before orthodontic treatment and evaluate the radiographic changes of temporomandibular joint during treatment. METHODS: Complete clinical recordings of 10,032 patients referring to the Orthodontic Department of Peking University School and Hospital of Stomatology from January 1998 to December 2003 were reviewed in present study. Patients with a history of previous orthodontic treatment, jaw surgery, facial trauma or systemic diseases which could potentially involve temporomandibular joint were excluded. The detection rate of TMJOA was calculated and its association with the possible risk factors of age, gender and malocclusion classifications was analyzed using the method of chi-square and multivariate logistic regression analysis. The clinical and radiographic characteristics were investigated and the radiographic findings before and after treatment were compared to evaluate the orthodontic effect on the articular bony structures. RESULTS: The detection rate of TMJOA in 10,032 patients before orthodontic treatment was 1.6% (159/10,032) and significantly higher in females (1.9%, 124/6,409) than in males(1.0%, 35/3,623)(chi-square = 13.925, P < 0.01).The detection rate increased positively with age (chi-square = 136.381, P < 0.01). Multivariate logistic regression analysis showed that patients with Angle II malocclusion were 1.683 times more likely to suffer from TMJOA compared with patients with Angle I malocclusion(Wald chi-square = 9.007, OR = 1.683, P < 0.01), while there was no significantly difference between the patients with Angle III and I malocclusion. Among the 85 TMJOA patients who finished their orthodontic treatments, 63 patients (74.1%, 63/85) maintained stable articular bony structure and the remaining 9(10.6%, 9/85) and 13 (15.3%, 13/85) patients showed recovering and deteriorating signs respectively according to the radiographs. CONCLUSION: The detection rate of TMJOA associated with age, gender and malocclusion classifications. Stable articular bony structure was maintained in the majority of the TMJOA patients (74.1%, 63/85) during the orthodontic treatments.

Cheek fistula from the ectopic salivary gland: a variant of the oculo-auriculo-vertebral spectrum.

OBJECTIVES/HYPOTHESIS: This study aimed to investigate the diagnosis and management of a distinct developmental deformity syndrome characterized by congenital cheek fistula, ectopic accessory parotid gland, and preauricular appendage. STUDY DESIGN: Retrospective study. METHODS: We analyzed the medical records, radiologic and histopathologic findings, and follow-up data for seven patients (four males) with a congenital cheek salivary fistula. Computed tomography, fistulography, and sialography had been performed for diagnosis. Surgical treatment effect was evaluated. RESULTS: The mean age of the patients was 8.1 years (range, 2-16 years). The distinctive clinical feature was a congenital skin orifice lateral to the commissure with saliva discharge during eating. The cheek fistulae were accompanied by ipsilateral preauricular appendages in all seven patients. The skin orifice connected to an ectopic gland anterior to the masseter and inferior to Stensen's duct. Parotid sialography demonstrated an intact Stensen's duct in all cases. Hypoplasia of the ipsilateral mandible could be observed in five cases. Excision of the ectopic gland, skin orifice, and fistula was performed in five cases resulting in optimal treatment outcomes with no recurrent or adverse events. CONCLUSIONS: A congenital saliva-discharging fistula with an ectopic accessory parotid gland, ipsilateral preauricular appendage, and mandibular hypoplasia constitutes a rare developmental syndrome. Surgical excision can effectively treat congenital cheek salivary fistula. LEVEL OF EVIDENCE: 4.

Craniofacial morphology of Chinese patients with bilateral temporomandibular joint osteoarthrosis.

OBJECTIVE: To evaluate the morphological features of craniofacial structures in young patients affected by bilateral temporomandibular joint osteoarthrosis (TMJOA). METHODS: Forty-three males and 189 females aged 15 to 25 years who had lateral cephalograms and temporomandibular joint (TMJ) radiological examinations were included. They were classified into a TMJOA group and a control group, according to TMJ bony status. Thirty-two variables from lateral cephalogram were analysed by t test to evaluate the cranial and dentofacial differences between the two groups. RESULTS: TMJOA group showed a shorter posterior ramus height and shorter condyles, smaller SNB angle and larger ANB angle, smaller facial plane angle and larger angle of convexity, steeper mandibular plane angle and more vertical y-axis. CONCLUSION: Bilateral TMJOA is associated with dentofacial alterations characterised by a tendency toward retrognathism and shorter mandibles. However, the cause-and-effect relationship is yet to be clarified.