Availability of CT and MR for Assessing Patients with Acute Stroke

Access to MRI Most hospitals that admitted patients with acute stroke had MRI facilities on site (192/245; 78%). Of the 192 hospitals with MR, 3 used mobile units which were not available 24 h a day. All the hospitals that had MR also had CT ( fig. 1 ). Forty-eight hospitals had on-site CT but no MRI. Of the 46 respondents, the average distance to an MRI machine was 37 km (range 0.8–129). Although more than three quarters of hospitals had MRI in their hospital, access for stroke patients was difficult. Seventythree percent of hospitals found MRI access difficult during working hours and 95% out of hours. Background Brain imaging is essential for the selection of stroke patients for thrombolysis. The imaging method must be available rapidly at all times, quick to perform, and able to exclude intracerebral haemorrhage and mimics of stroke [1] . Computerised tomography (CT) scanning is already widely available [2–4] and cost-effective [5] . However, signs on CT indicating ischaemic stroke are subtle within the first few hours of symptom onset and can be hard to see in people with leukoaraiosis or previous stroke [6] . Magnetic resonance imaging (MRI) may provide more information than CT in patients with acute stroke. For example, diffusion-weighted imaging (DWI) MR may be more sensitive than CT at detecting ischaemic stroke in patients with mild symptoms [7] , and gradient echo more sensitive for showing old haemorrhages in patients who present several days after their stroke [8] . There is increasing pressure that MR should be the method of choice to select patients with acute stroke for thrombolysis [9] and the firstline imaging method for all stroke [10] (though there are practical difficulties in performing MR in about 20% of stroke patients) [11, 12] . At least 2 acute stroke trials in progress are assessing the use of MRI DWI to select patients [13, 14] . If it is established that MR improves selection for thrombolysis, we sought to identify whether the UK would be in a position to provide this imaging modality for patients with acute stroke. We therefore surveyed all acute hospitals in the UK admitting patients with acute stroke to assess their access to MRI.