Dental radiography plays an important role in clinical diagnosis, treatment and surgery. In recent years, efforts have been made on developing computerized dental X-ray image analysis systems for clinical usages. A novel framework for objective evaluation of automatic dental radiography analysis algorithms has been established under the auspices of the IEEE International Symposium on Biomedical Imaging 2015 Bitewing Radiography Caries Detection Challenge and Cephalometric X-ray Image Analysis Challenge. In this article, we present the datasets, methods and results of the challenge and lay down the principles for future uses of this benchmark. The main contributions of the challenge include the creation of the dental anatomy data repository of bitewing radiographs, the creation of the anatomical abnormality classification data repository of cephalometric radiographs, and the definition of objective quantitative evaluation for comparison and ranking of the algorithms. With this benchmark, seven automatic methods for analysing cephalometric X-ray image and two automatic methods for detecting bitewing radiography caries have been compared, and detailed quantitative evaluation results are presented in this paper. Based on the quantitative evaluation results, we believe automatic dental radiography analysis is still a challenging and unsolved problem. The datasets and the evaluation software will be made available to the research community, further encouraging future developments in this field. (http://www-o.ntust.edu.tw/~cweiwang/ISBI2015/).

Cephalometric analysis is an essential clinical and research tool in orthodontics for the orthodontic analysis and treatment planning. This paper presents the evaluation of the methods submitted to the Automatic Cephalometric X-Ray Landmark Detection Challenge, held at the IEEE International Symposium on Biomedical Imaging 2014 with an on-site competition. The challenge was set to explore and compare automatic landmark detection methods in application to cephalometric X-ray images. Methods were evaluated on a common database including cephalograms of 300 patients aged six to 60 years, collected from the Dental Department, Tri-Service General Hospital, Taiwan, and manually marked anatomical landmarks as the ground truth data, generated by two experienced medical doctors. Quantitative evaluation was performed to compare the results of a representative selection of current methods submitted to the challenge. Experimental results show that three methods are able to achieve detection rates greater than 80% using the 4 mm precision range, but only one method achieves a detection rate greater than 70% using the 2 mm precision range, which is the acceptable precision range in clinical practice. The study provides insights into the performance of different landmark detection approaches under real-world conditions and highlights achievements and limitations of current image analysis techniques.

BackgroundSystemic inflammation, neurocognitive impairments, and morphologic brain changes are associated with obstructive sleep apnea (OSA). Understanding their longitudinal evolution and interactions after surgical treatment provides clues to the pathogenesis of cognitive impairment and its reversibility. In the present study, we investigate clinical disease severity, systemic inflammation, cognitive deficits, and corresponding gray matter volume (GMV) changes in OSA, and the modifications following surgery.MethodsTwenty-one patients with OSA (apnea-hypopnea index, AHI > 5) and 15 healthy volunteers (AHI < 5) underwent serial evaluation, including polysomnography, flow cytometry for leukocyte apoptosis categorization, cognitive function evaluation, and high-resolution brain scan. Disease severity, leukocyte apoptosis, cognitive function, and imaging data were collected to assess therapeutic efficacy 3 months after surgery.ResultsPre-operatively, patients presented with worse cognitive function, worse polysomnography scores, and higher early leukocyte apoptosis associated with increased insular GMV. There was reduced GMV in the anterior cingulate gyrus before and after surgery in the cases compared to that in controls, suggesting an irreversible structural deficit. Post-operatively, there were significant improvements in different cognitive domains, including attention, executive and visuospatial function, and depression, and in early leukocyte apoptosis. There was also a significant decrease in GMVs after treatment, suggesting recovery from vasogenic edema in the precuneus, insula, and cerebellum. Improvement in early leukocyte apoptosis post-surgery predicted better recovery of precuneus GMV.ConclusionsIn OSA, increased disease severity and systemic inflammation can alter GMV in vulnerable regions. Surgical treatment may improve disease severity and systemic inflammation, with subsequent recovery in brain structures and functions.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-016-0887-8) contains supplementary material, which is available to authorized users.

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The baroreflex maintains a stable blood pressure (BP) by dynamically adjusting heart rate (vagal component) and total peripheral resistance (adrenergic component). Vagal baroreflex sensitivity (BRS-v) is widely used but no methodology existed to quantitate adrenergic baroreflex sensitivity (BRS-a) until we developed the indices of BP recovery time (PRT) and BRS-a. The aims of this study were to generate a normative database and to evaluate whether there is an age effect on the cardiovagal and adrenergic sensitivities. We evaluated recordings of heart rate (HR) and BP in 255 normal subjects during the Valsalva maneuver (VM) and determined both BRS-v and BRS-a sensitivities. PRT increased with age whereas all other parameters declined with age. The adrenergic parameters correlated well with each other but not significantly with BRS-v. The results indicate that both BRS-a and BRS-v become blunted with increasing age and that these indices behave independently of each other.

The detection of anatomical landmarks in bioimages is a necessary but tedious step for geometric morphometrics studies in many research domains. We propose variants of a multi-resolution tree-based approach to speed-up the detection of landmarks in bioimages. We extensively evaluate our method variants on three different datasets (cephalometric, zebrafish, and drosophila images). We identify the key method parameters (notably the multi-resolution) and report results with respect to human ground truths and existing methods. Our method achieves recognition performances competitive with current existing approaches while being generic and fast. The algorithms are integrated in the open-source Cytomine software and we provide parameter configuration guidelines so that they can be easily exploited by end-users. Finally, datasets are readily available through a Cytomine server to foster future research.

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BackgroundVascular abnormalities are the predominant histologic changes associated with radiation in nasopharyngeal carcinoma (NPC). This study examined if the duration after radiotherapy correlates with the progression of carotid intima-media thickness (IMT) and investigated its relationship with inflammatory markers.MethodsOne hundred and five NPC patients post-radiotherapy for more than one year and 25 healthy control subjects were examined by B-mode ultrasound for IMT measurement at the far wall of the common carotid artery (CCA). Surrogate markers including lipid profile, HbA1c, and high sensitive C-reactive protein (hs-CRP) were assessed.ResultsThe IMT of CCA was significantly increased in NPC patients and carotid plaque was detected in 38 NPC patients (38/105, 36.2%). Significant risk factors for carotid plaques included age, duration after radiotherapy, and HbA1c levels. Age, duration after radiotherapy, hs-CRP, HbA1c, and platelet count positively correlated with IMT. The cut-off value of age and duration after radiotherapy for the presence of plaque was 52.5 years and 42.5 months, respectively. In NPC subjects, multiple linear regression analysis revealed that age, gender, duration after radiotherapy and platelet counts were independently associated with CCA IMT. After adjustments for age, gender and platelet counts, IMT increased in a linear manner with duration after radiotherapy.ConclusionsRadiation-induced vasculopathy is a dynamic and progressive process due to late radiation effects. Extra-cranial color-coded duplex sonography can be part of routine follow-up in NPC patients aged ≥50 years at 40 months post-radiotherapy.