Fetal Dosimetry at CT: A Primer.

CT scanning of a pregnant patient is often a source of distress for both patient and staff. Despite having expertise in image interpretation, a radiologist may not feel equipped to discuss the radiation-related safety issues during CT scanning of the fetus. In addition, patients are frequently concerned about the risk of adverse effects on the fetus from exposure to ionizing radiation. Recognizing the possibility of adverse effects from fetal exposure and the impossibility of direct in vivo measurement, medical physicists have developed several methods to estimate the amount of radiation reaching the fetus. A physician should know the potential biologic effects of fetal irradiation and at what radiation dose thresholds they occur. Physicians should also have an understanding of these methods and how the numbers they produce relate to potential fetal bioeffects. Furthermore, radiologists should have some understanding of how a qualified medical physicist calculates the fetal dose, how much they should trust those numbers, and the relevant variables that can affect the outcomes. Finally, the radiologist should know the magnitude of doses for CT scans commonly used in pregnant patients. Armed with this knowledge, a radiologist should be confident when discussing fetal dose and determining the best course of action for the pregnant patient. Online supplemental material is available for this article. ©RSNA, 2020.

Tracheomegaly among Extremely Preterm Infants on Prolonged Mechanical Ventilation.

By using phantom radiographs, the accuracy of tracheal measurements was established. Preterm infants (≤29 weeks) were enrolled in short (<7 days) and prolonged ventilation (≥28 days) groups. Both groups had 3 weight categories, namely, <1000 g, 1000-1999 g, and >2000 g. Tracheal sizes were measured on serial chest radiographs (CXR). We noted tracheomegaly in association with prolonged ventilation at ≥1000 g.

Sedation with Propofol During Catheter-Directed Thrombolysis for Acute Submassive Pulmonary Embolism Is Associated with Increased Mortality.

PURPOSE: To evaluate if sedation with propofol during catheter-directed thrombolysis (CDT) in patients with acute submassive pulmonary embolism (PE) affects survival. MATERIALS AND METHODS: This single-institution, retrospective study identified 136 patients from 2011-2017 who underwent CDT for acute submassive PE. Patients were grouped based on procedural sedation-propofol versus fentanyl and/or midazolam. Groups were compared for differences in baseline characteristics. Primary endpoint was in-hospital mortality. Logistic regression analysis was performed to evaluate for independent variables predictive of mortality. Propensity-matched analysis was also performed. RESULTS: Propofol was given to 18% (n = 25) of patients, and fentanyl and/or midazolam was given to 82% (n = 111) of patients. Mortality was 28% (n = 7) in the propofol group versus 3% (n = 3) in the fentanyl/midazolam group (P = .0003). Patients receiving propofol had 10.4 times the risk of cardiopulmonary arrest or dying during hospitalization compared with patients receiving fentanyl and/or midazolam (95% confidence interval, 2.9-37.3, P = .0003). The number needed to harm was 4 (95% confidence interval, 2.8-6.8). Logistic regression model analysis including Pulmonary Embolism Severity Index score, right-to-left ventricle diameter ratio and age was not predictive of mortality (P = .19). Adding type of sedation made the model predictive of mortality (P < .001). Propensity-matched analysis controlling for baseline differences in age, adjunctive maneuvers, American Society of Anesthesiologists class, and intubation before the procedure revealed that statistical significance between groups remained (P = .01). CONCLUSIONS: Sedation with propofol during CDT for acute submassive PE is associated with increased mortality and should be used with caution.

Complex Vascular Ring Diagnosed on Cardiovascular MR in a 3-Day-Old Infant.

Prenatal ultrasonography in the early third trimester showed an unusual branching pattern of the right aortic arch. Echocardiography performed 4 h after birth showed the right aortic arch with mirror-image branching, patent ductus arteriosus, and patent foramen ovale. Because the location of the ductus arteriosus was unclear on echocardiography, cardiovascular magnetic resonance imaging was performed 3 days after birth. Advanced techniques including contrast-enhanced time-resolved magnetic resonance angiography and 3D time-of-flight magnetic resonance angiography allowed accurate diagnosis of a vascular ring comprising ascending and descending aorta, right aortic arch with mirror-image branching, and diverticulum of Kommerell giving rise to a left ligamentum arteriosum. The infant had hiccups, but no other symptoms. The esophagram was negative for obstruction. The infant was closely monitored; however, she developed esophageal obstruction at 7 months of age because of the vascular ring. She underwent lysis of the left ligamentum arteriosum followed by aortopexy for relief of esophageal obstruction. This report shows the utility of neonatal cardiovascular magnetic resonance imaging to evaluate complex congenital aortic arch anomalies.