Robust framework for COVID-19 identication from a multicenter dataset of chest CT scans.

The main objective of this study is to develop a robust deep learning-based framework to distinguish COVID-19, Community-Acquired Pneumonia (CAP), and Normal cases based on volumetric chest CT scans, which are acquired in different imaging centers using different scanners and technical settings. We demonstrated that while our proposed model is trained on a relatively small dataset acquired from only one imaging center using a specific scanning protocol, it performs well on heterogeneous test sets obtained by multiple scanners using different technical parameters. We also showed that the model can be updated via an unsupervised approach to cope with the data shift between the train and test sets and enhance the robustness of the model upon receiving a new external dataset from a different center. More specifically, we extracted the subset of the test images for which the model generated a confident prediction and used the extracted subset along with the training set to retrain and update the benchmark model (the model trained on the initial train set). Finally, we adopted an ensemble architecture to aggregate the predictions from multiple versions of the model. For initial training and development purposes, an in-house dataset of 171 COVID-19, 60 CAP, and 76 Normal cases was used, which contained volumetric CT scans acquired from one imaging center using a single scanning protocol and standard radiation dose. To evaluate the model, we collected four different test sets retrospectively to investigate the effects of the shifts in the data characteristics on the model's performance. Among the test cases, there were CT scans with similar characteristics as the train set as well as noisy low-dose and ultra-low-dose CT scans. In addition, some test CT scans were obtained from patients with a history of cardiovascular diseases or surgeries. This dataset is referred to as the "SPGC-COVID" dataset. The entire test dataset used in this study contains 51 COVID-19, 28 CAP, and 51 Normal cases. Experimental results indicate that our proposed framework performs well on all test sets achieving total accuracy of 96.15% (95%CI: [91.25-98.74]), COVID-19 sensitivity of 96.08% (95%CI: [86.54-99.5]), CAP sensitivity of 92.86% (95%CI: [76.50-99.19]), Normal sensitivity of 98.04% (95%CI: [89.55-99.95]) while the confidence intervals are obtained using the significance level of 0.05. The obtained AUC values (One class vs Others) are 0.993 (95%CI: [0.977-1]), 0.989 (95%CI: [0.962-1]), and 0.990 (95%CI: [0.971-1]) for COVID-19, CAP, and Normal classes, respectively. The experimental results also demonstrate the capability of the proposed unsupervised enhancement approach in improving the performance and robustness of the model when being evaluated on varied external test sets.

Pancreatic Steatosis Evaluated by Automated Volumetric CT Fat Fraction of the Pancreas: Association with Severity in COVID-19 Pneumonia.

This study investigated the relationship between the severity of pneumonia based on chest CT findings and that of pancreatic steatosis assessed using an automated volumetric measurement of the CT fat volume fraction (CT-FVF) of the pancreas, using unenhanced three-dimensional CT in polymerase chain reaction (PCR)-confirmed COVID-19 patients. The study population consisted of 128 patients with PCR-confirmed COVID-19 infection who underwent CT examinations. The CT-FVF of the pancreas was calculated using a histogram analysis for the isolation of fat-containing voxels in the pancreas. The CT-FVF (%) of the pancreas had a significantly positive correlation with the lung severity score on CT (ρ = 0.549, p < 0.01). CT-FVF (%) of the pancreas in the severe pneumonia group was significantly higher than that of the non-severe pneumonia group (21.7% vs. 7.8%, p < 0.01). The area under the curve of CT-FVF (%) of the pancreas in predicting the severity of pneumonia on CT was calculated to be 0.82, with a sensitivity of 88% and a specificity of 68% at a threshold for the severity score of 12.3. The automated volumetric measurement of the CT-FVF of the pancreas using unenhanced CT can help estimate disease severity in patients with COVID-19 pneumonia based on chest CT findings.

"New Normal" Radiology.

COVID-19, the most recent and globally impactful zoonotic viral pandemic in the last 20 years, has now entered its third year. As the global dental profession returns to providing as full a range of services as possible, in addition to embedding the new infection-control processes that were developed for this pandemic, it should also take full advantage of digital conventional radiology (intraoral, extraoral, and panoramic radiography) and cone-beam computed tomography. Regardless of vaccinations, new or yet-to-manifest variants, and testing, some dentists may be working in communities where the asymptomatic but potentially infectious patient poses a real risk. This needs to be met with not only the whole COVID-19 panoply the dentist is already too familiar with but also the need to minimise aerosol generation production by dental radiography. A flowchart and a table that compares the attributes of the above modalities are included.

Progressive destruction of jaws caused by the delayed treatment of Langerhans cell histiocytosis in a 2-year-old boy: A case report.

Langerhans cell histiocytosis (LCH) is a disease with varied clinic manifestations. The oral symptoms and signs of LCH localized to the jaws are nonspecific, which may lead to misdiagnosis of this disease. The purpose of this paper was to present the case of a 2-year, 4-month-old LCH patient with progressive destruction of jaws caused by the delayed treatment due to the global outbreak of COVID-19. The cone beam CT analysis after an interval of 6 months reminded us the great significance of early diagnosis and treatment of LCH.

Improvement in bladder volume reproducibility using A-mode portable ultrasound bladder scanner in moderate-hypofractionated volumetric modulated arc therapy for prostate cancer patients.

PURPOSE: This study introduced an A-mode portable ultrasound bladder scanner, the Lilium® α-200 (here after Lilium; Lilium Otsuka, Kanagawa, Japan), for the treatment of prostate cancer patients with hypofractionated volumetric modulated arc therapy to improve the reproducibility of bladder volume (BV). MATERIALS AND METHODS: Thirty patients were advised to maintain full BV prior to computed tomography (CT) simulation and daily treatment. Among these, the BV of 15 patients was measured using Lilium until a BV of 80% in the simulation was achieved (with the Lilium group). Daily cone-beam CT (CBCT) was performed for treatment. The correlation between BV measured by CBCT and Lilium was assessed. The differences in the BV and dosimetric parameters of the bladder in the CBCT versus planning CT were compared between the groups with and without Lilium. RESULTS: There was a significantly strong relationship (r = 0.796, p < 0.05) between the BVs measured using CBCT and Lilium. The relative BV ratios to simulation CT < 0.5 and > 2 were observed in 10.3% and 12.7%, respectively, of treatment sessions without Lilium group, while these ratios were 1% and 2.8%, respectively, in the Lilium group. The mean absolute difference in the range of V30Gy to V40Gy without Lilium sessions was significantly larger (p < 0.05) than that in the Lilium group. CONCLUSION: The use of the A-mode portable ultrasound bladder scanner significantly improved the reproducibility of the BV, resulting in few variations in the dosimetric parameters for the bladder.

Delaying Intraoral Radiographs during the COVID-19 Pandemic: A Conundrum.

BACKGROUND: The COVID-19 pandemic has made dentists very assiduous about cross-infection during dental treatment, thereby delaying dental radiographs for treatment. However, patients needing dental emergency treatment in the ongoing pandemic require relevant intra/extraoral dental radiography for adequate diagnosis and treatment planning. METHODS: This article is aimed at adding to the hot debate: Is delay for intraoral radiographs justified or a possible proxy? As a narrative review, it provides an insight into the reasons for delaying intra-oral dental radiographs during in the pandemic and options of the nontraditional radiographic techniques available until the pandemic subsides. Discussion and Conclusion. Cross-contamination concerns through respiratory droplets grow while using intraoral film holders that stimulate gag reflex, coughing, saliva secretion, and if proper disinfection protocols are not applied. Since the patients' acquiring emergency dental treatment cannot be neglected, the return-to-work guidelines by the health regulatory bodies urge to prioritize extraoral radiographic imaging techniques to curb the infection, offering the best diagnostic efficacy. The dental professionals can consider cone-beam computed tomography (CBCT) scans and sectional dental panoramic radiographs (SDPRs), followed by a risk assessment for COVID-19, a safer modality in reducing cross-contamination and assuring an innocuous environment for both patient and coworkers.

Comparison of changes in skeletal, dentoalveolar, periodontal, and nasal structures after tooth-borne or bone-borne rapid maxillary expansion: A parallel cohort study.

INTRODUCTION: This parallel cohort study aimed to assess the dentoalveolar, skeletal, periodontal, and airway effects of tooth-borne (hyrax) and computer-guided miniscrew-supported rapid palatal expansion appliances. METHODS: Thirty-six subjects were randomly allocated into 2 groups. Eighteen subjects (mean age, 12.2 years; male-to-female ratio, 10:8) were assigned to receive treatment with the hyrax appliance (group A), and 18 subjects were treated with the computer-guided miniscrew-supported appliance (group B). The same type of expansion screw and expansion protocol was used in both groups. Linear and angular measurements of skeletal, dentoalveolar, periodontal, and nasal floor changes were performed on the pretreatment and posttreatment cone-beam computed tomography images (6-month follow-up). Descriptive statistics and the independent Student t test were used for the statistical analysis. Intraoperator reliability was evaluated using a 2 sample t test. The level of significance was P ≤0.05. RESULTS: Ten subjects were censured because posttreatment cone-beam computed tomography imaging was not performed because of the coronavirus disease 2019 pandemic. In the remaining 26 subjects, increases in linear measurements were observed in both groups. The transversal skeletal increase was greater and statistically significant in the group treated with the bone-borne expander (P ≤0.05). The dentoalveolar transverse diameters were greater in the tooth-supported expander group, with no statistically significant difference between the groups. The buccal inclination of the maxillary first molar was observed in the group with the tooth-borne expander, with a statistically significant difference between the 2 groups. A slight reduction of buccal and palatal thicknesses at the level of the maxillary first molars was observed in both groups, smaller in the skeletal expander group, with a statistically significant difference between the 2 groups only on the right buccal cortical plate. The width of the nasal floor increased more in the group with skeletal expander with a statistically significant difference of 2 mm. CONCLUSIONS: Computer-guided miniscrew-supported maxillary expanders allowed a greater transversal increase of the nasal-maxillary skeletal structures by reducing the dentoalveolar side effects of the tooth-supported devices.

Imaging-guided radiofrequency ablation of osteoid osteoma in typical and atypical sites: Long term follow up.

PURPOSE: To assess efficacy and safety of imaging-guided radiofrequency ablation (RFA) of Osteoid Osteoma (OO) in both typical and atypical sites. METHODS AND MATERIALS: Between January 2014 and March 2019, 102 consecutive percutaneous RFA were performed and retrospectively reviewed. The procedures were performed using a RFA bipolar ablation system (Covidien, exposed tip of 0.7-1cm), under Computed Tomography (CT) guidance or using a navigation system (Masmec) under CT and Cone Beam CT (CBCT) guidance. Patients were followed up over 24 months. Clinical success and recurrences were considered on the base of established criteria. In patients with clinical failure and/or imaging evidence of relapse, retreatment was considered. RESULTS: Administered power per-procedure was ≤8 W (mean temperature, 90°C). The pre-procedure average value of visual analog scale (VAS) was 8.33+/-0.91. Primary and secondary success rate 96.08% (98/102) and100% (102/102), respectively. No major complication was described. Technical success was proved in every patient by CT scan acquisition after needle positioning. Relapse and tumour location were significantly correlated (p-value = 0.0165). The mean dose-length product was 751.55 mGycm2. Advanced bone healing was noted in 68 lesions after 1y-follow up and in 86 lesions after 2y-follow up. CONCLUSION: Imaging-guided percutaneous RFA is a highly effective technique for OO, both in typical and atypical sites. CT or CBCT guidance, navigation systems and operator experience grant the technical success, which is the most crucial parameter affecting outcome.

A rare entity to major outbreak: a case report on mucormycosis.

Mucormycosis is relatively uncommon, fulminant, progressive, life threatening fungal disease which is most often seen in debilitating patients with immunocompromised condition. Mucormycosis cases are seen in patients with the use of systemic steroids in the treatment of severely affected COVID-19 cases and also in the patients with uncontrolled diabetes which causes immunosuppression are being reported with mucormycosis. The main symptoms of this disease include pain on the temporal and the orbital region of the affected side which could be throbbing or lancinating type, mobility of the teeth, jaw pain and often swelling is present which could be extraoral and intraoral both or sometimes only intraorally. The diagnostic approach in such cases is done with the help of clinical diagnosis, histopathology and with advanced imaging like cone beam computed tomography, magnetic resonance imaging and computed tomography. We here used cone beam computed tomography imaging that revealed haziness in the sinuses and breach in cortical bone of the affected area which confirmed the diagnosis of mucormycosis. Early treatment planning like administration of antifungal drugs and surgical debridement will be life saving in such a deadly disease.

Automated quantitative thin slice volumetric low dose CT analysis predicts disease severity in COVID-19 patients.

PURPOSE: This study aimed to identify predictive (bio-)markers for COVID-19 severity derived from automated quantitative thin slice low dose volumetric CT analysis, clinical chemistry and lung function testing. METHODS: Seventy-four COVID-19 patients admitted between March 16th and June 3rd 2020 to the Asklepios Lung Clinic Munich-Gauting, Germany, were included in the study. Patients were categorized in a non-severe group including patients hospitalized on general wards only and in a severe group including patients requiring intensive care treatment. Fully automated quantification of CT scans was performed via IMBIO CT Lung Texture analysis™ software. Predictive biomarkers were assessed with receiver-operator-curve and likelihood analysis. RESULTS: Fifty-five patients (44% female) presented with non-severe COVID-19 and 19 patients (32% female) with severe disease. Five fatalities were reported in the severe group. Accurate automated CT analysis was possible with 61 CTs (82%). Disease severity was linked to lower residual normal lung (72.5% vs 87%, p = 0.003), increased ground glass opacities (GGO) (8% vs 5%, p = 0.031) and increased reticular pattern (8% vs 2%, p = 0.025). Disease severity was associated with advanced age (76 vs 59 years, p = 0.001) and elevated serum C-reactive protein (CRP, 92.2 vs 36.3 mg/L, p < 0.001), lactate dehydrogenase (LDH, 485 vs 268 IU/L, p < 0.001) and oxygen supplementation (p < 0.001) upon admission. Predictive risk factors for the development of severe COVID-19 were oxygen supplementation, LDH >313 IU/L, CRP >71 mg/L, <70% normal lung texture, >12.5% GGO and >4.5% reticular pattern. CONCLUSION: Automated low dose CT analysis upon admission might be a useful tool to predict COVID-19 severity in patients.

Cone Beam Computed Tomography (CBCT) Technology and Learning Outcomes in Dental Anatomy Education: E-Learning Approach.

E-learning is an educational method that improves knowledge innovation by sharing relevant images for advanced learning, especially in a pandemic state. Furthermore, cone-beam computed tomography (CBCT) is a method that gathers medical or dental diagnostic images. This study aimed to analyze the effectiveness of dental anatomy education through a CBCT technology tool, through teachers' and students' perspectives, adjusted according to the disruptions caused by the Covid-19 pandemic. A cohort study and longitudinal exploratory analysis were performed. Forty undergraduate first-year dental students, from the University of Coimbra in Portugal, were selected as per the inclusion and exclusion criteria. Two different teaching methods were applied during an identical time-period: face-to-face lectures complemented by physical models (T1 cohort) and webinar lectures complemented by CBCT images (T2 cohort). Learning outcomes were then studied according to theoretical and spatial orientation contexts. A self-reported survey that focused on students' satisfaction, stress, and support was studied. Both teaching methods were analyzed with paired sample student's t-test and Pearson Correlation Confidence intervals 95% with P < 0.05. Furthermore, exploratory factor analysis (EFA) was used for self-reported satisfaction survey validity and reliability analysis. The learning outcomes between T1 and T2 cohorts were statistically significant, (P < 0.001) corresponding to differences with a large effect degree (r > 0.60). Students' satisfaction, as measured on a six-point Likert scale, was positively influenced by the webinar lectures supplemented with CBCT images (T2 cohort) in a learning context (4.95 ± 0.5) and future applications (5.92 ± 0.27). In conclusion, the webinar approach with CBCT images was more effective and better learning method for teaching dental anatomy.

Novel 3D segmentation for reliable volumetric assessment of the nasal airway: a CBCT study.

OBJECTIVE: Nasal airway obstruction affects up to one-third of Americans and is one of the most common complaints by patients to otolaryngologists. Nasal airway obstruction and obstructive sleep apnea syndrome (OSAS) are closely related. The aim of this study was to use the 3D imaging software, ITK-SNAP as a platform to define a gold standard for anatomically accurate boundaries of the nasal airway in 3D CBCT and to create a more reliable and precise 3D CBCT segmentation of the nasal airway for assisting diagnosis, treatment, and monitoring of nasal airway obstruction and OSAS. METHOD AND MATERIALS: After review of the literature to identify established parameters using CBCT and CT technology for the segmentation of the nasal airway, and the existing drawbacks, a gold standard for locating the anatomical boundaries of the nasal airway using CBCT is proposed. This new method aims at standardization of segmentation and quantification, allowing for more reliable comparison between studies. ITK-SNAP software was used to segment three CBCT samples of healthy patients aged 21 to 59 years, who were patients of record, with CBCT obtained for either orthodontic, endodontic, or prosthodontic treatment planning purposes.
Results: The literature search identified 11 studies describing nasal airway parameters utilizing CBCT and CT. A great variation was detected on where the anatomical boundaries for the nasal airway were selected. A new standard in the identification of anatomical boundaries of the nasal airway is proposed for consistent segmentation and quantification using 3D CBCT by using the following landmarks: the inferior ANS-PNS border, the anterior nares border, the posterior sella-PNS border, and superiorly the border in alignment with the base of the skull (excluding the ostia, frontal, ethmoidal, and sphenoidal air cells). The three segmented samples were volumetrically measured, and statistically analyzed. The mean average Hounsfield unit intensity using the CBCT samples in this study was 629 with a standard deviation of 190.
Conclusion: The literature indicates a lack of a gold standard using CBCT technology for the segmentation of the nasal airway. With the proposed standard in this study, it is possible to quantify the nasal airway volume and thereby its reduction. For the general dental practitioner, this is an important aspect during the evaluation of overall airway assessment. This information can be useful in the diagnosis and treatment of airway compromised dental patients. (Quintessence Int 2021;52:154-164; doi: 10.3290/j.qi.a45429).

Effect of Surgical Mask on Setup Error in Head and Neck Radiotherapy.

PURPOSE: With the widespread prevalence of Corona Virus Disease 2019 (COVID-19), cancer patients are suggested to wear a surgical mask during radiation treatment. In this study, cone beam CT (CBCT) was used to investigate the effect of surgical mask on setup errors in head and neck radiotherapy. METHODS: A total of 91 patients with head and neck tumors were selected. CBCT was performed to localize target volume after patient set up. The images obtained by CBCT before treatment were automatically registered with CT images and manually fine-tuned. The setup errors of patients in 6 directions of Vrt, Lng, Lat, Pitch, Roll and Rotation were recorded. The patients were divided into groups according to whether they wore the surgical mask, the type of immobilization mask used and the location of the isocenter. The setup errors of patients were calculated. A t-test was performed to detect whether it was statistically significant. RESULTS: In the 4 groups, the standard deviation in the directions of Lng and Pitch of the with surgical mask group were all higher than that in the without surgical mask group. In the head-neck-shoulder mask group, the mean in the Lng direction of the with surgical mask group was larger than that of the without surgical mask group. In the lateral isocenter group, the mean in the Lng and Pitch directions of the with surgical mask group were larger than that of the without surgical mask group. The t-test results showed that there was significant difference in the setup error between the 2 groups (p = 0.043 and p = 0.013, respectively) only in the Lng and Pitch directions of the head-neck-shoulder mask group. In addition, the setup error of 6 patients with immobilization open masks exhibited no distinguished difference from that of the patients with regular immobilization masks. CONCLUSION: In the head and neck radiotherapy patients, the setup error was affected by wearing surgical mask. It is recommended that the immobilization open mask should be used when the patient cannot finish the whole treatment with a surgical mask.