# Temporal and geographical variations in musculoskeletal imaging: a register-based study in Norway with focus on potential low-value imaging

## TL;DR

This study examines changes over time and differences across regions in musculoskeletal imaging in Norway, focusing on potentially unnecessary MRI scans of the knee and lower back.

## Contribution

The study provides new insights into geographical and temporal variations in potentially low-value musculoskeletal imaging in Norway.

## Key findings

- The use of musculoskeletal imaging in Norway decreased by 6.8% from 2013 to 2022.
- Geographical variations were highest for potential low-value MRI scans, with the highest-use region performing over twice as many as the lowest-use region.
- Temporal variations in imaging use were small, but substantial differences were observed between hospital trusts.

## Abstract

Musculoskeletal (MSK) issues generate extensive use of diagnostic imaging. Geographical variations in imaging are of interest as they can indicate under- and overutilisation. Low-value imaging is defined as examinations where evidence suggests it confers no or very little benefit on patients.

To assess the temporal and geographical variations in MSK imaging with special attention to two potential low-value MSK examinations, i.e. MRI of knee and MRI of lower back, in Norway from 2013 to 2022.

Both inpatient and outpatient examinations from 2013 to 2022 were included. Data on outpatients was collected from the Norwegian Health Economics Administration, while inpatient data was gathered directly from strategically selected hospitals in Norway. Missing inpatient data was extrapolated based on population and outpatient data for each hospital trust. The rates are adjusted for age and sex to the European Standard Population.

Yearly, 1,884,614 MSK examinations were conducted in Norway. I.e. 3,586 examinations per 10,000 inhabitants. The use of MSK imaging decreased by 6.8% during the study period. The geographical variations were highest for the use of the potential low-value MSK examinations, where the region with the highest use conducted over twice as many examinations than the region with the lowest use.

The temporal variations in the use of MSK examinations was small. However, there were substantial geographical variations between the hospital trusts, and modest variations between the regional health trusts. Reducing low-value examinations could free up resources for examinations with high value.

The online version contains supplementary material available at 10.1007/s43999-025-00077-x.