Geographical variations in the use of outpatient diagnostic imaging in Norway 2019

Geographical variations in the use of outpatient imaging can reveal inappropriate use of radiological services. Knowledge about these variations is crucial in the strive for appropriate and improved services.

To investigate the geographical variations in outpatient diagnostic imaging and analyze variations for main groups of examinations and for specific examinations.

Data on outpatient radiological procedures registered at the Norwegian Health Economics Administration in Norway for 2019 were accessed with county-based population rates for age adjustment accessed through Statistics Norway. Age-adjusted rates were used to calculate high/low ratios, means, standard deviations, and coefficients of variation were calculated per 10,000 inhabitants.

There is high geographical variation for PET/CT and PET/MRI and moderate variation for neuroradiological outpatient examinations in Norway in 2019. Variations for the musculoskeletal systems and of thorax, abdomen, and vessels are almost 50%. We find high high-to-low ratios in CT-face (9.7), MRI-elbow joint (8.5), CT of the neck, thorax, abdomen, and pelvis (6.5) as well as MRI-prostate (6.2). Comparing with data from 2012-5, we find a reduction in variation for some examinations, such as MRI of the hip and MRI of the entire spine, and an increase in variations for others, such as CT of the face and MRI of the elbow joint.

Despite much attention to the problem, we demonstrate substantial variations in radiological services in Norway raising concern with respect to appropriateness, quality of care, equity, and justice. The findings provide important input for quality improvement in radiological services.