Chest imaging in pregnant patients with COVID-19: Recommendations, justification, and optimization.

Evaluation of COVID-19 related complication is challenging in pregnancy, due to concerns about ionizing radiation risk to mother and the fetus. Although there are instances when diagnostic imaging is clinically warranted for COVID-19 evaluation despite the minimal risks of radiation exposure, often there are concerns raised by the patients and sometimes by the attending physicians. This article reviews the current recommendations on indications of chest imaging in pregnant patients with COVID-19, the dose optimization strategies, and the risks related to imaging exposure during pregnancy. In clinical practice, these imaging strategies are key in addressing the complex obstetrical complications associated with COVID-19 pneumonia.

Utility of MRCP in surveillance of primary sclerosing cholangitis associated hepatobiliary malignancy: 15 year experience at a single institution in Ontario, Canada.

OBJECTIVE: Magnetic resonance cholangiopancreatography (MRCP) is used for the surveillance of primary sclerosing cholangitis (PSC) and its associated complications. The time interval gap for subsequent follow-up MRCP is variable depending on clinical practice patterns, therefore this study was done to assess the MRCP follow-up strategy used in our institution for screening PSC-associated hepatobiliary malignancies. MATERIALS AND METHODS: This retrospective observational cohort included MRCP studies in adult patients, with clinical and radiological diagnosis of PSC over the past 15-year period between January 1, 2003 to December 31, 2018. The study population was grouped based on the presence and absence of PSC-associated malignancy. The frequency of MRCP follow-up was compared between the groups to look for MRI ordering trends in surveillance for PSC-associated complications. RESULTS: The overall median interval follow-up with MRCP was 14 months. The median follow-up interval in cases with PSC-associated malignancy was 6.0 months, compared to 13.1 months in the PSC group without malignancy (p 0.013). During the study period, the PSC-associated malignancy group had a median number of 7.5 scans, while the no malignancy group had a median number of 4 scans. Three patients (3/10, 30%) developed hepatobiliary malignancies within the first year of clinical diagnosis of PSC. The most common malignancy associated with PSC was cholangiocarcinoma (4.6%,7/10). Other PSC-associated malignancies included carcinoma gallbladder (1.3%,2/10), and hepatocellular carcinoma (0.6%,1/10). The median age of PSC associated malignancies was 56 (IQR 15) and higher compared to median age of PSC group without malignancies 46 (IQR 25.5), p 0.035. CONCLUSION: The median interval for subsequent follow-up MRCP in our study cohort was 14 months. One-third of PSC-associated hepato-biliary malignancies developed within the first year of clinical diagnosis of PSC, and the risk of PSC-associated hepato-biliary malignancy is constant after the first year.

Diagnostic accuracy and inter-observer agreement with the CO-RADS lexicon for CT chest reporting in COVID-19.

PURPOSE: To measure the diagnostic accuracy and inter-observer agreement with the use of COVID-19 Reporting and Data System (CO-RADS) for detection of COVID-19 on CT chest imaging. METHODS: This retrospective study included 164 consecutive patients with clinical suspicion of COVID-19 in whom a CT chest examination was performed at a single institution between April 2020 and July 2020. Of them, 101 patients was RT-PCR positive for COVID-19. Six readers with varying radiological experience (two each of chest radiologists, general radiologists, and radiologists in training) independently assigned a CO-RADS assessment category for each CT chest study. The Fleiss' K was used to quantify inter-observer agreement. The inter-observer agreement was also assessed based on the duration of onset of symptoms to CT scan. ROC curve analysis was used to determine the diagnostic accuracy of CO-RADS. The area under curve was calculated to determine the reader accuracy for detection of COVID-19 lung involvement with RT-PCR as reference standards. The data sets were plotted in ROC space, and Youden's J statistic was calculated to determine the threshold cut-off CO-RADS category for COVID-19 positivity. RESULTS: There was overall moderate inter-observer agreement between all readers (Fleiss' K 0.54 [95% CI 0.54, 0.54]), with substantial agreement among chest radiologists (Fleiss' K 0.68 [95% CI 0.67, 0.68]), general radiologists (Fleiss' K 0.61 [95% CI 0.61, 0.61]), and moderate agreement among radiologists-in-training (Fleiss' K 0.56 [95% CI 0.56, 0.56]). There was overall moderate inter-observer agreement in early disease (stages 1 and 2), with cumulative Fleiss' K 0.45 [95% CI 0.45, 0.45]). The overall AUC for CO-RADS lexicon scheme to accurately diagnose COVID-19 yielded 0.92 (95% CI 0.91, 0.94) with strong concordance within and between groups, of chests radiologists with AUC of 0.91 (95% CI 0.88, 0.94), general radiologists with AUC 0.96 (95% CI 0.94, 0.98), and radiologists in training with AUC of 0.90 (95% CI 0.87, 0.94). For detecting COVID-19, ROC curve analysis yielded CO-RADS > 3 as the cut-off threshold with sensitivity 90% (95% CI 0.88, 0.93), and specificity of 87% (95% CI 0.83, 0.91). CONCLUSION: Readers across different levels of experience could accurately identify COVID-19 positive patients using the CO-RADS lexicon with moderate inter-observer agreement and high diagnostic accuracy.

Utility of visual coronary artery calcification on non-cardiac gated thoracic CT in predicting clinical severity and outcome in COVID-19.

BACKGROUND: Assessment of visual-coronary artery calcification on non-cardiac gated CT in COVID-19 patients could provide an objective approach to rapidly identify and triage clinically severe patients for early hospital admission to avert worse prognosis. PURPOSE: To ascertain the role of semi-quantitative scoring in visual-coronary artery calcification score (V-CACS) for predicting the clinical severity and outcome in patients with COVID-19. MATERIALS AND METHODS: With institutional review board approval this study included 67 COVID-19 confirmed patients who underwent non-cardiac gated CT chest in an inpatient setting. Two blinded radiologist (Radiologist-1 &2) assessed the V-CACS, CT Chest severity score (CT-SS). The clinical data including the requirement for oxygen support, assisted ventilation, ICU admission and outcome was assessed, and patients were clinically subdivided depending on clinical severity. Logistic regression analyses were performed to identify independent predictors. ROC curves analysis is performed for the assessment of performance and Pearson correlation were performed to looks for the associations. RESULTS: V-CACS cut off value of 3 (82.67% sensitivity and 54.55% specificity; AUC 0.75) and CT-SS with a cut off value of 21.5 (95.7% sensitivity and 63.6% specificity; AUC 0.87) are independent predictors for clinical severity and also the need for ICU admission or assisted ventilation. The pooling of both CT-SS and V-CACS (82.67% sensitivity and 86.4% specificity; AUC 0.92) are more reliable in terms of predicting the primary outcome of COVID-19 patients. On regression analysis, V-CACS and CT-SS are individual independent predictors of clinical severity in COVID-19 (Odds ratio, 1.72; 95% CI, 0.99-2.98; p = 0.05 and Odds ratio, 1.22; 95% CI, 1.08-1.39; p = 0.001 respectively). The area under the curve (AUC) for pooled V-CACS and CT-SS was 0.96 (95% CI 0.84-0.98) which correctly predicted 82.1% cases. CONCLUSION: Logistic regression model using pooled Visual-Coronary artery calcification score and CT Chest severity score in non-cardiac gated CT can predict clinical severity and outcome in patients with COVID-19.