Should magnetic resonance imaging or computed tomography be the primary brain imaging modality in the transient ischemic attack clinic?

OBJECTIVE The Royal College of Physicians and National Institute of Clinical Excellence have recommended that magnetic resonance imaging should be the modality of choice for cerebral imaging in transient ischemic attack patients. However, implementation of this is often difficult. Therefore, it is important to know whether magnetic resonance imaging contributes significantly to early clinical management in transient ischemic attack patients. DESIGN A retrospective case-notes review of 65 consecutive patients seen by one neurology trainee (with consultant review), in a neurovascular service where computed tomography has been the primary cerebral imaging modality. SETTING Outpatient TIA/Neurovascular clinic at Imperial College hospital. PARTICIPANTS 65 consecutive patients seen by one neurology trainee (with consultant review). MAIN OUTCOME MEASURE We recorded the preliminary clinical diagnosis, details of investigations performed and whether or not patients had a magnetic resonance imaging brain scan subsequently, the number followed up in clinic and the final diagnosis. RESULTS Of the 65 cases seen, 55% were classified initially as transient ischemic attack/stroke mimics. Of the 29 cases (45%) that were classified as transient ischemic attack, all had computed tomography scans, 12 had magnetic resonance imaging scans subsequently and 14 were followed up several weeks later. Of the 36 cases classified as stroke mimics, 27 had computed tomography scans immediately and 31 had carotid Dopplers, six subsequently had magnetic resonance imaging scans and 14 were followed up in clinic. Only two patients had their diagnosis revised on the basis of the magnetic resonance imaging. CONCLUSIONS Our study suggests that magnetic resonance imaging brain changes the diagnosis in a relatively small percentage of cases. A good history and examination remain paramount in the assessment of patients presenting to the transient ischemic attack clinic, particularly when more than 50% of cases referred are transient ischemic attack/stroke mimics.