Diagnosis of acute fractures of the extremities: comparison of low-field MRI and conventional radiography

The aim of this study was to compare low-field MRI (0.2 T) and conventional radiography for the detection of acute fractures of the distal part of the extremities. X-ray and MRI examinations of 78 (41 fractures, 37 without fracture) patients with the clinical suspicion of an acute fracture in the distal part of the extremities were compared. Four experienced radiologists, two for each of the two modalities, independently analyzed the images. Interobserver variability and receiver operating characteristic (ROC) analysis for both methods were established. The MRI and conventional radiography revealed an accuracy of 81.4 and of 79.5%, respectively, in the detection of acute fractures. The diagnostic accuracy of MRI to detect fractures in the hand and forefoot proved to be significantly inferior to conventional X-ray examinations. On the other hand, MRI achieved a better accuracy for the examination of bones near a large joint. The interobserver variability for both methods was rated as moderate. In ROC analysis both methods were rated as good. There was no statistical difference of the accuracy between low-field MRI and conventional radiography in the detection of acute fractures of the distal part of the extremities. Consequently, a routine use of low-field MRI as an alternative to conventional radiography to diagnose acute fractures of the extremities seems not to be justified.