AbbreviationsCOVID-19 (coronavirus disease 2019), CT (computed tomography), CXR (chest radiograph), RT-PCR (reverse transcriptase-polymerase chain reaction), ICU (intensive care unit), WBC (white blood cell), LDH (lactate dehydrogenase), CRP (C-reactive protein) SummaryVaccinated patients with COVID-19 breakthrough infections showed fewer chest CT findings of pneumonia compared to unvaccinated patients. Key Results1. Of 761 hospitalized patients with COVID-19 disease and chest radiographs, 77% (587/761) were in unvaccinated patients while breakthrough infection in fully vaccinated subjects occurred in 6.2% (47/761) patients.2. The initial chest x-ray showed no pneumonia in 75% of fully vaccinated patients with breakthrough infection and 63% of unvaccinated patients (p=.37).3. In 412 patients with chest CT during hospitalization, a CT showed no pneumonia in 59% of fully vaccinated patients with breakthrough infection and 27% of unvaccinated patients (p=.01).

Background Few reports have evaluated the effect of the SARS-CoV-2 variant and vaccination on the clinical and imaging features of COVID-19. Purpose To evaluate and compare the effect of vaccination and variant prevalence on the clinical and imaging features of infections by the SARS-CoV-2. Materials and Methods Consecutive adults hospitalized for confirmed COVID-19 at three centers (two academic medical centers and one community hospital) and registered in a nationwide open data repository for COVID-19 between August 2021 and March 2022 were retrospectively included. All patients had available chest radiographs or CT. Patients were divided into two groups according to predominant variant type over the study period. Differences between clinical and imaging features were analyzed using Pearson χ 2 test, Fisher exact test, or the independent t-test. Multivariable logistic regression analyses were used to evaluate the effect of variant predominance and vaccination status on imaging features of pneumonia and clinical severity. Results Of the 2180 patients (mean age, 57 years ± 21, 1171 women), 1022 patients (46%) were treated during the Delta variant predominant period and 1158 (54%) during the Omicron period. The Omicron variant prevalence was associated with lower pneumonia severity based on CT scores (OR, 0.71 [95% CI: 0.51, 0.99; P = .04]) and lower clinical severity based on ICU admission or in-hospital death (OR 0.43, 95% CI: 0.24, 0.77, P = .004) than the Delta variant prevalence. Vaccination was associated with the lowest odds of severe pneumonia based on CT scores (OR 0.05, 95% CI:0.03, 0.13, P < .001) and clinical severity based on ICU admission or in-hospital death (OR 0.15, 95% CI: 0.07, 0.31, P < .001) relative to no vaccination. Conclusion The SARS-CoV-2 Omicron variant prevalence and vaccination were associated with better clinical outcomes and lower severe pneumonia risk relative to Delta variant prevalence.

A number of studies have evaluated the variable courses of facial artery. However, the results of these differed substantially from each other so not consistent relationships have yet been established. There has also yet to be a relevant study using conventional angiography. We assessed the variant branching pattern of the facial artery and its branches using conventional angiography. Two radiologists retrospectively reviewed 284 cases of angiographies of the external carotid artery in 198 patients. The courses of the facial artery and infraorbital branch of the maxillary artery were classified into 4 types and 2 types, according to the end branch. Among 284 cases of facial artery, type 1 (angular branch) made up 104 cases (36.6%), type 2 (lateral nasal branch) made up 138 cases (48.6%), type 3 (superior labial branch) made up 24 cases (8.5%), and type 4 (inferior labial branch) made up 18 cases (6.3%). Regarding the 284 total cases of maxillary artery, 163 cases (57.4%) had anastomosis with the angular artery or extended to the territory of the angular artery. In addition, 121 cases (42.6%) had nothing done in regard to the angular artery. The results may be helpful for avoiding complications related to facial and maxillary arteries during facial surgeries and cosmetic procedures.

Background and Objectives: Although reducing the radiation dose level is important during diagnostic computed tomography (CT) applications, effective image quality enhancement strategies are crucial to compensate for the degradation that is caused by a dose reduction. We performed this prospective study to quantify emphysema on ultra-low-dose CT images that were reconstructed using deep learning-based image reconstruction (DLIR) algorithms, and compared and evaluated the accuracies of DLIR algorithms versus standard-dose CT. Materials and Methods: A total of 32 patients were prospectively enrolled, and all underwent standard-dose and ultra-low-dose (120 kVp; CTDIvol < 0.7 mGy) chest CT scans at the same time in a single examination. A total of six image datasets (filtered back projection (FBP) for standard-dose CT, and FBP, adaptive statistical iterative reconstruction (ASIR-V) 50%, DLIR-low, DLIR-medium, DLIR-high for ultra-low-dose CT) were reconstructed for each patient. Image noise values, emphysema indices, total lung volumes, and mean lung attenuations were measured in the six image datasets and compared (one-way repeated measures ANOVA). Results: The mean effective doses for standard-dose and ultra-low-dose CT scans were 3.43 ± 0.57 mSv and 0.39 ± 0.03 mSv, respectively (p < 0.001). The total lung volume and mean lung attenuation of five image datasets of ultra-low-dose CT scans, emphysema indices of ultra-low-dose CT scans reconstructed using ASIR-V 50 or DLIR-low, and the image noise of ultra-low-dose CT scans that were reconstructed using DLIR-low were not different from those of standard-dose CT scans. Conclusions: Ultra-low-dose CT images that were reconstructed using DLIR-low were found to be useful for emphysema quantification at a radiation dose of only 11% of that required for standard-dose CT.

Acute phlegmonous esophagitis is a very rare, life-threatening form of esophagitis, characterized by diffuse bacterial infection and pus formation within the submucosal and muscularis layers of the esophagus. We describe a case in which contrast-enhanced chest CT was useful for evaluating the severity of phlegmonous esophagitis, which was overlooked and underestimated by endoscopy.