Implementation of CAD/CAM program in a nonface-to-face classroom environment due to the COVID-19 pandemic.

PURPOSE/OBJECTIVES: This study aimed to evaluate a nonface-to-face crown designing module in a preclinical dental course. METHODS: Free dental planning software (Blue Sky Plan) was installed on the personal computers of dental college students, and a #46 full veneer crown designing practice was performed individually. An online survey was conducted on the computers' specification and main usage of the students, the practice process, and results. Statistical analysis was conducted to analyze the association between variables, such as "operating system," "central processing unit ," "number of cores," "random-access memory (RAM)," "graphic card," and task performance. RESULTS: Of the D2 students, 75.4% (52 of 69) responded to the survey. Overall, 96% of the respondents used their computers, and all respondents had no problem running the program. Most of the students marked their level of computer literacy as intermediate and had purchased the computers for the purpose of performing light work. The most common specifications of the computer were Intel i5, quad core, 8 GB RAM, and Windows 10. Students had little experience with computer-aided design/computer-aided manufacturing before the class. The relationship between computer specifications and task performance was not statistically significant. CONCLUSIONS: Overall, students with intermediate-level computer literacy used computers with less than the recommended specifications of the program; however, they were able to run the program and individually proceed with modules to submit results. Using an individually available crown designing program can provide an opportunity to diversify curricula and broaden students' perspectives even under circumstances like the COVID-19 pandemic that limits intimate face-to face classes.

Chest CT Findings in Hospitalized Patients with SARS-CoV-2: Delta versus Omicron Variants.

Background CT manifestations of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) may differ among variants. Purpose To compare the chest CT findings of SARS-CoV-2 between the Delta and Omicron variants. Materials and Methods This retrospective study collected consecutive baseline chest CT images of hospitalized patients with SARS-CoV-2 from a secondary referral hospital when the Delta and Omicron variants predominated. Two radiologists categorized CT images based on the Radiological Society of North America classification system for coronavirus disease 2019 (COVID-19) and visually graded pneumonia extent. Pneumonia, pleural effusion, and intrapulmonary vessels were segmented and quantified on CT images using a priori developed neural networks, followed by reader confirmation. Multivariable logistic and linear regression analyses were performed to examine the associations between the variants and CT category, distribution, severity, and peripheral vascularity. Results In total, 88 patients with the Delta (mean age, 67 years±15; 46 men) and 88 patients with the Omicron (mean age, 62 years±19; 51 men) variants were included. Omicron was associated with a less frequent typical peripheral, bilateral ground-glass opacity (32% [28/88] versus 57% [50/88]; P=.001), more frequent peri-bronchovascular predilection (38% [25/66] versus 7% [5/71]; P<.001), lower visual pneumonia extent (5.4±6.0 versus 7.7±6.6; P=.02), similar pneumonia volume (5%±10 versus 7%±11; P=.14), and a higher proportion of vessels with a cross-sectional area smaller than 5 mm2 relative to the total pulmonary blood volume (BV5%; 48%±11 versus 44%±8; P=.004). In adjusted analyses, Omicron was associated with a non-typical appearance (odds ratio, 0.34; P=.006), peri-bronchovascular predilection (odds ratio, 9.2; P<.001), and higher BV5% (ß value, 3.8; P=.01) but similar visual pneumonia extent (P=.17) and pneumonia volume (P=.67) relative to Delta variant. Conclusions On chest CT, the Omicron SARS-COV-2 variant showed nontypical, peri-bronchovascular pneumonia and less pulmonary vascular involvement than the Delta variant in hospitalized patients with comparable CT disease severity.

An Integrated Radiologic-Pathologic Understanding of COVID-19 Pneumonia.

This article reviews the radiologic and pathologic findings of the epithelial and endothelial injuries in COVID-19 pneumonia to help radiologists understand the fundamental nature of the disease. The radiologic and pathologic manifestations of COVID-19 pneumonia result from epithelial and endothelial injuries based on viral toxicity and immunopathologic effects. The pathologic features of mild and reversible COVID-19 pneumonia involve nonspecific pneumonia or an organizing pneumonia pattern, while the pathologic features of potentially fatal and irreversible COVID-19 pneumonia are characterized by diffuse alveolar damage followed by fibrosis or acute fibrinous organizing pneumonia. These pathologic responses of epithelial injuries observed in COVID-19 pneumonia are not specific to SARS-CoV-2 but rather constitute universal responses to viral pneumonia. Endothelial injury in COVID-19 pneumonia is a prominent feature compared with other types of viral pneumonia and encompasses various vascular abnormalities at different levels, including pulmonary thromboembolism, vascular engorgement, peripheral vascular reduction, a vascular tree-in-bud pattern, and lung perfusion abnormality. Chest CT with different imaging techniques (eg, CT quantification, dual-energy CT perfusion) can fully capture the various manifestations of epithelial and endothelial injuries. CT can thus aid in establishing prognosis and identifying patients at risk for deterioration.

Long-term treatment outcome of Castleman's disease: A real-world experience.

Background: Castleman disease (CD), classified as unicentric CD (UCD) or multicentric CD (MCD), is a rare non-neoplastic lymphoproliferative disorder of unknown origin. Owing to its rarity, the clinical characteristics, therapeutic modalities, treatment outcomes, and prognostic factors related to UCD or MCD are not well defined. Method: We retrospectively analyzed 88 patients with CD, including those with hyaline-vascular, plasma-cell, mixed type, hypervascular, and plasmablastic subtypes, for presenting symptoms, physical, laboratory, and radiologic findings, and treatment response in the Korean population. Results: The median patient age was 44 years (range: 18-84 years) with slight predominance of women (53.4%). UCD and MCD accounted for 38.6% (n=34) and 61.4% (n=54) of cases, respectively. Histopathologically, UCD patients were classified as 88.2% (n=30) hyaline-vascular and 11.8% (n=4) plasma cell types, whereas MCD patients were classified as 27.8% (n=15) hypervascular, 61.1% (n=33) plasma cell, 7.4% (n=4) mixed, and 3.7% (n=2) plasmablastic types. Twelve (13.6%) patients exhibited a poor performance status with an Eastern Cooperative Oncology Group score of 2. The most common presenting symptom was sustained fever, followed by fatigue, anorexia, peripheral edema, and weight loss. Furthermore, splenomegaly, pleural effusion, and ascites were observed to be associated with CD. Surgical resection and siltuximab were the preferred treatment modalities for UCD and MCD, respectively, with favorable symptomatic, laboratory, and radiologic outcomes and safety profiles. The overall survival was 90.2%, with no significant difference between the UCD and MCD groups (p=0.073), but progression-free survival was significantly poorer in the MCD group (p=0.001). Age ≥60 years and splenomegaly significantly affected the overall and progression-free survival rates. Conclusion: Patients with UCD had favorable outcomes with surgical resection of a solitary mass, whereas in patients with MCD, old age and splenomegaly were identified as independent prognostic factors. Further well-designed prospective studies under advancing knowledge of the pathophysiology of MCD are warranted to establish suitable guidelines for the discontinuation or prolonging infusion intervals of siltuximab and treatment modalities for HHV-8 positive MCD patients or patients with siltuximab failure.

Pulmonary function and chest computed tomography abnormalities 6-12 months after recovery from COVID-19: a systematic review and meta-analysis.

BACKGROUND: Some coronavirus disease 2019 (COVID-19) survivors experience prolonged and varying symptoms, a condition termed post-acute COVID-19 syndrome (PACS). However, the prevalence of chronic pulmonary sequelae of PACS during long-term follow-up remains unclear. Several studies have examined this issue and reported heterogeneous results. METHODS: We conducted a systematic review and meta-analysis using a random-effects model to estimate the pooled prevalence of the pulmonary sequelae of COVID-19, as demonstrated by pulmonary function testing (PFT) and chest computed tomography (CT) performed at least 6 months after initial infection. PubMed, Embase, and Cochrane Library databases were searched from January 1, 2020 to December 31, 2021 to identify related studies. We investigated whether the prevalence of pulmonary sequelae decreased over time and attempted to identify the factors associated with their development by performing multiple subgroup and meta-regression analyses. RESULTS: Of the 18,062 studies identified, 30 met our eligibility criteria. Among these studies, 25 and 22 had follow-up PFT and chest CT data, respectively. The follow-up durations were approximately 6 and 12 months in 18 and 12 studies, respectively. Impaired diffusion capacity was the most common abnormality on PFT (pooled prevalence 35%, 95% confidence interval [CI] 30-41%) with a prevalence of 39% (95% CI 34-45%) and 31% (95% CI 21-40%) in the 6-month and 12-month follow-up studies, respectively (P = 0.115). Restrictive pulmonary dysfunction evident as reduced forced vital capacity was less frequent (pooled prevalence 8%, 95% CI 6-11%); however, its prevalence was lower in the 12-month follow-up studies than in the 6-month follow-up studies (5% [95% CI 3-7%] vs. 13% [95% CI 8-19%], P = 0.006). On follow-up chest CT, the pooled prevalence of persistent ground-glass opacities and pulmonary fibrosis was 34% (95% CI 24-44%) and 32% (95% CI 23-40%), respectively, and the prevalence did not decrease over time. As every meta-analysis showed significant between-study heterogeneity, subgroup and meta-regression analyses were performed to identify potential effect modifiers; the severity of index infection was associated with the prevalence of impaired diffusion capacity and pulmonary fibrosis. CONCLUSIONS: A substantial number of COVID-19 survivors displayed pulmonary sequelae as part of PACS. Except for restrictive pulmonary dysfunction, the prevalence of these sequelae did not decrease until 1 year after initial infection. Considering the association between the severity of acute COVID-19 and risk of pulmonary sequelae, patients who recover from severe COVID-19 require close respiratory follow-up. Systematic review registration number PROSPERO CRD42021234357.

CT Examinations for COVID-19: A Systematic Review of Protocols, Radiation Dose, and Numbers Needed to Diagnose and Predict.

Purpose: Although chest CT has been discussed as a first-line test for coronavirus disease 2019 (COVID-19), little research has explored the implications of CT exposure in the population. To review chest CT protocols and radiation doses in COVID-19 publications and explore the number needed to diagnose (NND) and the number needed to predict (NNP) if CT is used as a first-line test. Materials and Methods: We searched nine highly cited radiology journals to identify studies discussing the CT-based diagnosis of COVID-19 pneumonia. Study-level information on the CT protocol and radiation dose was collected, and the doses were compared with each national diagnostic reference level (DRL). The NND and NNP, which depends on the test positive rate (TPR), were calculated, given a CT sensitivity of 94% (95% confidence interval [CI]: 91%-96%) and specificity of 37% (95% CI: 26%-50%), and applied to the early outbreak in Wuhan, New York, and Italy. Results: From 86 studies, the CT protocol and radiation dose were reported in 81 (94.2%) and 17 studies (19.8%), respectively. Low-dose chest CT was used more than twice as often as standard-dose chest CT (39.5% vs.18.6%), while the remaining studies (44.2%) did not provide relevant information. The radiation doses were lower than the national DRLs in 15 of the 17 studies (88.2%) that reported doses. The NND was 3.2 scans (95% CI: 2.2-6.0). The NNPs at TPRs of 50%, 25%, 10%, and 5% were 2.2, 3.6, 8.0, 15.5 scans, respectively. In Wuhan, 35418 (TPR, 58%; 95% CI: 27710-56755) to 44840 (TPR, 38%; 95% CI: 35161-68164) individuals were estimated to have undergone CT examinations to diagnose 17365 patients. During the early surge in New York and Italy, daily NNDs changed up to 5.4 and 10.9 times, respectively, within 10 weeks. Conclusion: Low-dose CT protocols were described in less than half of COVID-19 publications, and radiation doses were frequently lacking. The number of populations involved in a first-line diagnostic CT test could vary dynamically according to daily TPR; therefore, caution is required in future planning.