Magnetic resonance imaging - Application to family practice

OBJECTIVE To review indications, contraindications, and risks of using magn etic resonance imaging (MRI) in order to help primary care physicians refer patients appropriately for MRI, screen for contraindications to using MRI, and educate patients about MRI. QUALITY OF EVIDENCE Recommendations are based on classic textbooks, the pol icies of our MRI group, and a literature search using MEDLINE with the MeSH headings magnetic resonance imaging, brain, musculoskeletal, and spine. Th e search was limited to human, English-language, and review articles. Evide nce in favour of using MRI for imaging the head, spine, and joints is well established. For cardiac, abdominal, and pelvic conditions, MRI has been sh own useful for certain indications, usually to complement other modalities. MAIN MESSAGE For demonstrating soft tissue conditions, MRI is better than c omputed tomography (CT), but CT shows bone and acute bleeding better. There fore, patients with trauma or suspected intracranial bleeding should have C T. Tumours, congenital abnormalities, vascular structures, and the cervical or thoracic spine show better on MRI. Either modality can be used for lowe r back pain. Cardiac, abdominal, and pelvic abnormalities should be imaged with ultrasound or CT before MRI. Contraindications for MRI are mainly meta llic implants or shrapnel, severe claustrophobia, or obesity. CONCLUSIONS With the increasing availability of MRI scanners in Canada, bet ter understanding of the indications, contraindications, and risks will be helpful for family physicians and their patients.