Initial Experience with a COVID-19 Screening Chatbot Before Radiology Appointments.

Guidelines for COVID-19 issued by the Centers for Disease Control and Prevention prompted state and local governments to mandate safety measures for screening high-risk patient populations and for institutions to look for ways to limit human contact when possible. The aim of this study was to determine the feasibility of an automated communication system (chatbot) for COVID-19 screening before patients' radiology appointments and to describe patient experiences with the chatbot. We developed a chatbot for COVID-19 screening before outpatient radiology examination appointments and tested it in a pilot study from July 6 to August 31, 2020. The chatbot assessed the presence of any symptoms, exposure, and recent testing. User experience was assessed via a questionnaire based on a 5-point Likert scale. Multivariable logistic regression was performed to predict response rate. The chatbot COVID-19 screening SMS message was sent to 4687 patients. Of these patients, 2722 (58.1%) responded. Of the respondents, 46 (1.7%) reported COVID-19 symptoms; 34 (1.2%) had COVID-19 tests scheduled or pending. Of the 1965 nonresponders, authentication failed for 174 (8.8%), 1496 (76.1%) did not engage with the SMS message, and 251 (12.8%) timed out of the chatbot. The mean rating for the chatbot experience was 4.6. In a multivariable logistic regression model predicting response rate, English written-language preference independently predicted response (odds ratio, 2.71 [95% CI, 1.77-2.77]; P = .007). Age (P = 0.57) and sex (P = 0.51) did not predict response rate. SMS-based COVID-19 screening before scheduled radiology appointments was feasible. English written-language preference (not age or sex) was associated with higher response rate.

Breast Radiation Dose With CESM Compared With 2D FFDM and 3D Tomosynthesis Mammography.

OBJECTIVE: We aimed to compare radiation dose received during contrast-enhanced spectral mammography (CESM) using high- and low-energy projections with radiation dose received during 2D full field digital mammography (FFDM) and 3D tomosynthesis on phantoms and patients with varying breast thickness and density. MATERIALS AND METHODS: A single left craniocaudal projection was chosen to determine the doses for 6214 patients who underwent 2D FFDM, 3662 patients who underwent 3D tomosynthesis, and 173 patients who underwent CESM in this retrospective study. Dose measurements were also collected in phantoms with composition mimicking nondense and dense breast tissue. RESULTS: Average glandular dose (AGD) ± SD was 3.0 ± 1.1 mGy for CESM exposures at a mean breast thickness of 63 mm. At this thickness, the dose was 2.1 mGy from 2D FFDM and 2.5 mGy from 3D tomosynthesis. The nondense phantom had a mean AGD of 1.0 mGy with 2D FFDM, 1.3 mGy with 3D tomosynthesis, and 1.6 mGy with CESM. The dense breast phantom had a mean AGD of 1.3 mGy with 2D FFDM, 1.4 mGy with 3D tomosynthesis, and 2.1 mGy with CESM. At a compressed thickness of 4.5 cm, radiation exposure from CESM was approximately 25% higher in dense breast phantoms than in nondense breast phantoms. The dose in the dense phantom at a compressed thickness of 6 cm was approximately 42% higher than the dose in the nondense phantom at a compressed thickness of 4.5 cm. CONCLUSION: CESM was found to increase AGD at a mean breast thickness of 63 mm by approximately 0.9 mGy and 0.5 mGy compared with 2D FFDM and 3D tomosynthesis, respectively. Of note, CESM provides a standard image (similar to 2D FFDM) that is obtained using the low-energy projection. Overall, the AGD from CESM falls below the dose limit of 3 mGy set by Mammography Quality Standards Act regulations.

Radiologic diagnoses of patients who received imaging for venous thromboembolism despite negative D-dimer tests.

OBJECTIVE: The literature supports a negative D-dimer (-DD) excluding venous thromboembolic disease (VTE) in low-risk patients. We determined the radiologic diagnoses in patients where imaging was ordered despite a -DD. METHODS: This is a retrospective chart review of patients with a -DD (Tinaquant; Roche Diagnostics, Mannheim, Germany) and a radiologic study within 48 hours, sought to determine radiologic diagnosis (primary outcome), treatment of VTE, and consensus diagnosis of acute VTE. RESULTS: Among 3462 DD tests, 1678 met the inclusion criteria. Of 1362 patients with DD values of 350 ng/mL or less, 166 (12.2%) had radiologic studies: 93.4% of the final radiologic diagnoses were negative for VTE, 3.6% were indeterminate, and 3.0% (1.0%-6.9%) were positive; 1.8% ultimately had a consensus diagnosis of acute VTE. In 316 patients with DD values between 351 and 500 ng/mL, 88 (27.8%) had radiologic studies: 95.5% were negative, 1.1% were indeterminate, and 3.4% (0.7%-9.6%) were positive. CONCLUSIONS: Of patients who receive radiologic studies despite -DD tests, 3.0% have positive radiologic diagnoses for acute VTE; only 1.8% had acute VTE after the review of their hospital course.