Cardiovascular Testing in the United States during the COVID-19 Pandemic: Volume Recovery and Worldwide Comparison

Purpose

To characterize the recovery of diagnostic cardiovascular procedure volumes in U.S. and non-U.S. facilities in the year following the initial COVID-19 outbreak.

Materials and Methods

The International Atomic Energy Agency (IAEA) coordinated a worldwide study called the IAEA Noninvasive Cardiology Protocols Study of COVID-19 2 (INCAPS COVID 2), collecting data from 669 facilities in 107 countries, including 93 facilities in 34 U.S. states, to determine the impact of the pandemic on diagnostic cardiovascular procedure volumes. Participants reported volumes for each diagnostic imaging modality used at their facility for March 2019 (baseline), April 2020, and April 2021. This secondary analysis of INCAPS COVID 2 evaluated differences in changes in procedure volume between U.S. and non-U.S. facilities and among U.S. regions. Factors associated with return to prepandemic volumes in the United States were also analyzed in a multivariable regression analysis.

Results

Reduction in procedure volumes in April 2020 compared with baseline was similar for U.S. and non-U.S. facilities (-66% vs -71%, P = .27). U.S. facilities reported greater return to baseline in April 2021 than did all non-U.S. facilities (4% vs -6%, P = .008), but there was no evidence of a difference when comparing U.S. facilities with non-U.S. high-income country (NUHIC) facilities (4% vs 0%, P = .18). U.S. regional differences in return to baseline were observed between the Midwest (11%), Northeast (9%), South (1%), and West (-7%, P = .03), but no studied factors were significant predictors of 2021 change from prepandemic baseline.

Conclusion

The reductions in cardiac testing during the early pandemic have recovered within a year to prepandemic baselines in the United States and NUHICs, while procedure volumes remain depressed in lower-income countries.Keywords: SPECT, Cardiac, Epidemiology, Angiography, CT Angiography, CT, Echocardiography, SPECT/CT, MR Imaging, Radionuclide Studies, COVID-19, Cardiovascular Imaging, Diagnostic Cardiovascular Procedure, Cardiovascular Disease, Cardiac Testing Supplemental material is available for this article. © RSNA, 2023.

Cardiac Imaging Trends from 2010 to 2019 in the Medicare Population

Purpose

To evaluate changes in utilization of cardiac imaging-transthoracic, transesophageal, and stress echocardiography (TTE, TEE, and SE), coronary CT angiography (cCTA), cardiac MRI (cMRI), myocardial perfusion imaging (MPI), and cardiac positron emission tomography (cPET).

Materials and Methods

The 2010-2019 Physician/Supplier Procedure Summary files were used to find imaging utilization per 100 000 Medicare beneficiaries. Global and professional claims were aggregated, representing total interpretive services. Specialty codes identified provider specialty. Results were stratified by physician offices, hospital outpatient departments (HOPDs), inpatient setting, and the emergency department.

Results

From 2010 to 2019, there was a partial shift from cardiologist offices to the HOPD for TTE (office: -23%; HOPD: +107%) and SE (office: -44%; HOPD: +11%). Cardiologist cCTA also shifted from the office (-57%) to the HOPD (+211%). Radiologist-performed cCTA grew in all locations but most in the HOPD (+355%), with radiologists performing more cCTA than cardiologists in all settings. cMRI rates remain low but rose in the HOPD for both cardiologists (+209%) and radiologists (+207%). Cardiologist MPI rates dropped dramatically in the office (-52%), with a smaller absolute rate increase in the HOPD (+71%). cPET nearly tripled in the cardiology office (+193%), but rates remained steady for radiologists.

Conclusion

While most cardiologist in-office imaging has shifted to the HOPD, there has been an increase in in-office cPET, likely due to a combination of technological advances, interpretation familiarity, and financial incentives. Radiologist cCTA rates continue to increase, representing a growing opportunity for radiologists to collaborate in cardiac imaging.Keywords: CT Angiography, Echocardiography, MR Imaging, PET, Radionuclide Studies, SPECT, Cardiac, Work Force Issues Supplemental material is available for this article. © RSNA, 2021.

Multimodal Bone Metastasis-associated Epidermal Growth Factor Receptor Imaging in an Orthotopic Rat Model

Purpose To develop multimodality imaging techniques for measuring epidermal growth factor receptor (EGFR) as a therapy-relevant and metastasis-associated molecular marker in triple-negative mammary adenocarcinoma metastases. Materials and Methods An orthotopic bone metastasis EGFR-positive, triple-negative breast cancer (TNBC) model in rats was used for bioluminescence imaging, SPECT/CT, PET/CT, and MRI with quantitative analysis of transcripts (n = 22 rats). Receptor-specific MRI of EGFR expression in vivo was performed by acquiring spin-echo T1-weighted images after sequential administration of a pair of anti-EGFR antigen binding fragments, F(ab')₂, conjugated to either horseradish peroxidase or glucose oxidase, which have complementing activities, as well as paramagnetic (gadolinium[III]-mono-5-hydroxytryptamide of 2,2',2''-(10-(2,6-dioxotetrahydro-2H-pyran-3-yl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid, or Gd-5HT-DOTAGA) or positron-emitting (gallium 68-5HT-DOTAGA) substrates for MRI and PET/CT imaging, respectively. EGFR expression was confirmed by quantitative reverse transcriptase polymerase chain reaction and immunohistochemical analyses to compare with image findings. Results After surgical intraarterial delivery of TNBC cells, rats developed tumors that diverged into either rapidly growing osteolytic or slow-growing nonosteolytic tumors. Both tumor types showed receptor-specific initial MRI signal enhancement (contrast-to-noise ratio) that was three to six times higher than that of normal bone marrow (29.4 vs 4.9; P < .01). Micro PET/CT imaging of EGFR expression demonstrated a high level of heterogeneity with regional uptake of the tracer, which corresponded to region-of-interest MRI signal intensity elevation (121.1 vs 93.3; P < .001). Analysis of metastases with corroboration of imaging results showed high levels of EGFR protein and messenger RNA, or mRNA, expression in the invasive tumor. Conclusion Convergence of multimodal molecular receptor imaging enabled comprehensive assessment of EGFR overexpression in an orthotopic model of TNBC metastasis. Keywords: Animal Studies, Molecular Imaging-Cancer, MR-Contrast Agent, Radionuclide Studies, Skeletal-Appendicular, Metastases Supplemental material is available for this article. © RSNA, 2021.