Growth rates in cross-sectional abdominal imaging studies by imaging modality and patient class: an increasing proportion of acute care examinations has implications for future needs

OBJECTIVE: The purpose of this study was to assess abdominal imaging utilization across a large healthcare system over a 10-year period to compare growth rates and relative distribution of exams among patient classes (emergency department [ED] patients, inpatients [IP], and outpatients [OP]) and across cross-sectional imaging modalities. METHODS: Data from all abdominal computed tomography (CT), ultrasound (US), and magnetic resonance imaging (MRI) examinations performed in ED patients, inpatients, and outpatients were collected from a large healthcare system over a 10-year period (January 2014 through December 2023). Poisson regression analysis was used to model the number of examinations over time. Additional models were constructed to assess trends over time for each modality and for each patient class. RESULTS: Over the study period, 3,408,471 imaging studies were performed in 1,150,921 patients. ED volumes showed the largest average increase, 15.9% per year which was significantly greater than the 14.6% average annual increase for inpatients and 10.5% for outpatients. The average annual increases by modality were 14.5% for MRI, 14.4% for CT, and 10.7% for US. The percentage of acute care cases (IP and ED) relative to all exams significantly increased from 41.7% in 2014 to 52% in 2023. CONCLUSIONS: This study demonstrated a pattern of near-continuous annual growth in abdominal imaging examinations across all patient classes and major modalities over a 10-year period, with an increasing contribution of acute care cases. These findings highlight areas of need for resources.