Pulmonary Embolism in Hospitalized Patients with COVID-19: A Multicenter Study.

Background Pulmonary embolism (PE) commonly complicates SARS-CoV-2 infection, but incidence and mortality reported in single-center studies, along with risk factors, vary. Purpose To determine the incidence of PE in patients with COVID-19 and its associations with clinical and laboratory parameters. Materials and Methods In this HIPAA-compliant study, electronic medical records were searched retrospectively for demographic, clinical, and laboratory data and outcomes among patients with COVID-19 admitted at four hospitals from March through June 2020. PE found at CT pulmonary angiography and perfusion scintigraphy was correlated with clinical and laboratory parameters. The d-dimer level was used to predict PE, and the obtained threshold was externally validated among 85 hospitalized patients with COVID-19 at a fifth hospital. The association between right-sided heart strain and embolic burden was evaluated in patients with PE undergoing echocardiography. Results A total of 413 patients with COVID-19 (mean age, 60 years ± 16 [standard deviation]; age range, 20-98 years; 230 men) were evaluated. PE was diagnosed in 102 (25%; 95% CI: 21, 29) of 413 hospitalized patients with COVID-19 who underwent CT pulmonary angiography or perfusion scintigraphy. PE was observed in 21 (29%; 95% CI: 19, 41) of 73 patients in the intensive care unit (ICU) versus 81 (24%; 95% CI: 20, 29) of 340 patients who were not in the ICU (P = .37). PE was associated with male sex (odds ratio [OR], 1.74; 95% CI: 1.1, 2.8; P = .02); smoking (OR, 1.86; 95% CI: 1.0, 3.4; P = .04); and increased d-dimer (P < .001), lactate dehydrogenase (P < .001), ferritin (P = .001), and interleukin-6 (P = .02) levels. Mortality in hospitalized patients was similar between patients with PE and those without PE (14% [13 of 102]; 95% CI: 8, 22] vs 13% [40 of 311]; 95% CI: 9, 17; P = .98), suggesting that diagnosis and treatment of PE were not associated with excess mortality. The d-dimer levels greater than 1600 ng/mL [8.761 nmol/L] helped predict PE with 100% sensitivity and 62% specificity in an external validation cohort. Embolic burden was higher in patients with right-sided heart strain among the patients with PE undergoing echocardiography (P = .03). Conclusion Pulmonary embolism (PE) incidence was 25% in patients hospitalized with COVID-19 suspected of having PE. A d-dimer level greater than 1600 ng/mL [8.761 nmol/L] was sensitive for identification of patients who needed CT pulmonary angiography. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Ketai in this issue.

The radiation exposure associated with cervical and lumbar spine radiographs.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: To calculate the effective radiation doses of routine anteroposterior (AP) and lateral radiographs of the cervical and lumbar spines. SUMMARY OF BACKGROUND DATA: Although plain radiographs are generally used as the initial imaging modality for the evaluation of patients with spinal complaints, the radiation that patients receive during these studies has not been well quantified. The effective radiation dose represents a functional measure of exposure that takes into account the amount of radiation delivered and the radiosensitivity of the exposed organs. Consequently, the effective dose is important to consider from a radiation safety perspective. METHODS: The imaging practices of our radiology department were reviewed and the effective radiation doses for AP and lateral radiographs of the cervical and lumbar spines were calculated using the following variables: emitted radiation dose, source-to-object distance [SOD], film area, and patient tissue dimensions. Values were obtained from both direct measurements and an examination of the established protocols employed at our institution. RESULTS: The effective doses for AP and lateral cervical radiographs were 0.12 and 0.02 mSv, respectively, whereas the corresponding values for AP and lateral lumbar films were much larger (2.20 and 1.50 mSv, respectively). For comparative purposes, a typical chest x-ray results in a radiation dose between 0.06 and 0.25 mSv. CONCLUSIONS: In this investigation, cervical spine films gave rise to radiation doses that are similar to those of chest x-rays. However, lumbar spine radiographs generated effective radiation doses that were approximately an order of magnitude greater than these other studies. In both the cervical and lumbar regions, AP views resulted in significantly greater radiation exposure than corresponding lateral images. The effective radiation doses reported here may prove to be valuable for assessing the relative risks and benefits of spine radiographs to establish appropriate guidelines for their use.

Can high-attenuation renal cysts be differentiated from renal cell carcinoma at unenhanced CT?

PURPOSE: To retrospectively determine if renal cell carcinoma can be differentiated from high-attenuation renal cysts at unenhanced computed tomography (CT) based on Hounsfield unit measurements and heterogeneity. MATERIALS AND METHODS: The Human Investigation Committee at our institution approved this study with waiver of informed consent. This study was compliant with the HIPAA. Fifty-four pathologically proved renal cell carcinomas in 54 patients (36 men and 18 women; average age, 53 years; range, 23-90 years) and 56 high-attenuation renal cysts in 51 patients (30 men and 21 women; average age, 63 years; range, 28-86 years) were retrospectively evaluated at unenhanced CT. Two independent readers reviewed randomized unenhanced CT images and obtained Hounsfield unit readings of each mass. A subjective determination of lesion heterogeneity was also performed by using a four-point scale (1: homogeneous, 2: mildly heterogeneous, 3: moderately heterogeneous, 4: markedly heterogeneous). Statistical analysis was performed by using Bland-Altman regression tree, classification and regression tree, and Shapiro-Wilk normality test. RESULTS: The average attenuation of cysts for reader 1 was 53.4 HU (range, 23-113 HU) and for reader 2 was 53.8 HU (range, 21-108 HU). The average attenuation of neoplasms for reader 1 was 34.7 HU (range, 21-60 HU) and for reader 2 was 38.4 HU (range, 22-60 HU). For cyst heterogeneity, a score of 1 was given in 55 of 56 (98%) cysts for reader 1 and in 53 of 56 (95%) cysts for reader 2. For neoplasm heterogeneity, a score of 1 was given in 35 of 54 (65%) neoplasms for reader 1 and in 36 of 54 (67%) for reader 2. Given the distribution of cyst and tumor attenuation values and lesion heterogeneity, a homogeneous mass measuring 70 HU or greater at unenhanced CT has a greater than 99.9% chance of representing a high-attenuation renal cyst. CONCLUSION: The findings from this study may help differentiate high-attenuation renal cysts from renal cell carcinomas at unenhanced CT and may suggest the next appropriate imaging study for definitive characterization.

Infarcted splenule--a case report.

A 38-year-old woman presented with abdominal pain and left shoulder pain. A computed tomography scan was obtained, which demonstrated a rounded soft tissue density with surrounding stranding. It was interpreted as an infarcted splenule. Due to the increasing severity of the patient's symptoms, a laparoscopic exploration was performed. Pathology demonstrated an infarcted splenule. As infarcted splenules are rare, an understanding of its pathogenesis and familiarity with the corresponding imaging findings may be helpful for its diagnosis in the patient with the appropriate clinical scenario. It is important to recognize this entity as a cause of abdominal pain that can be managed nonsurgically.

What characterizes academic radiology departments that secure large amounts of external funding for research?

RATIONALE AND OBJECTIVES: We sought to identify factors associated with high levels of external research funding in order to provide departments with information that may help them increase their external research funding. MATERIALS AND METHODS: National Institutes of Health (NIH) data on grants were analyzed to identify the 72 radiology departments receiving funds for diagnostic radiology research. A survey was sent to these departments. We placed them into one of three categories according to total NIH funds to the department. The survey asked about department characteristics such as size; breakdown of full-time faculty among MDs, MD/PhDs, and PhDs; research space; equipment type; and number and types of trainees. RESULTS: Thirty-nine surveys were returned, including 20 from the 21 departments with the most NIH funding. PhDs played a larger role in the most research funding-intensive departments than in others. These departments also were more likely than others to give protected time to all MDs and to devote over 5% of clinical revenues to research, and they had a lower clinical workload per MD. NIH was the source of 70% of their research funding, The role of MD/PhDs and research space per 1000 research dollars did not vary by research intensity. CONCLUSIONS: These findings only demonstrate associations; they do not show the direction of causality. Nonetheless, they suggest what departments need to do if they wish to increase their external research funding.