[Sciatalgy: which imaging in first intention?].

Lombosciatalgy is a very common pathology and accounts for one of the most important problems of the public health. Usually it is a symptom that decreases with medical treatment. MRI or CT examinations may be asked for when symptoms persist for more than 7 weeks after medical treatment, symptoms increase or if there is a manipulation or infiltration foreseen. When there is a doubt on the specific origin of the symptoms, in other words when the pathology is secondary to an inflammatory/infectious, traumatic or tumoral aetiology, X-rays are performed followed by a complementary examination by CT or MRI. A CT-scan will be performed mainly in the workup of pathology of the intervertebral disk, or in a posttraumatic setting. An MRI is advisable when there is a suspicion of a primary or secondary tumour, infection or inflammation and in stenosis of the spinal canal.