Background and Purpose - Many patients with transient ischemic attack (TIA) or minor stroke present to medical attention after a delay of several days or weeks, at which time it may be more difficult to obtain a clear history and clinical signs may have resolved. Because ischemic lesions on diffusion- weighted MRI (DWI) often persist for several weeks, we hypothesized that adding DWI to a standard protocol with T2- weighted imaging might be useful in the management of patients presenting late. Methods - We studied consecutive patients with TIA or minor stroke presenting ≥ 3 days after the event. Two independent observers recorded the presence or absence of recent ischemic lesions on 2 different occasions, first with the T2 scan only, and second with T2 and DWI. Each time, with the aid of a written clinical summary, the observers recorded their diagnosis and proposed management. Results - 300 patients (159 men) were scanned at a median of 17 (interquartile range=10 to 23) days after symptom onset. DWI showed a high signal lesion in 114/164 (70% ) minor strokes versus 17/136 (13% ) TIAs (P < 0.0001). The presence of high- signal lesions on DWI decreased nonlinearly with time since symptom onset (F < 0.0001) and increased with National Institutes of Health Stroke Score (P=0.038) and with age (P=0- 01). In 90/206 (43.7% ) patients with 1 or multiple lesions on T2, DWI helped to clarify whether these were related to a recent ischemic event (79 [48% Abstract: strokes; 11 [31% Abstract:- TIAs). Compared with T2 alone, DWI provided additional information in 108 (36% ) patients (91 [56% Abstract: strokes and 17 [13% Abstract: TIAs), such as clarification of clinical diagnosis (18 patients, 6% ) or vascular territory (28 patients, 93% ), which was considered likely to influence management in 42 (14% )- patients (32 [19% Abstract: strokes; 10 [7.4% Abstract: TIAs). Conclusions - The clinically useful information available from DWI provides a further justification for an MRI- based imaging protocol in patients with subacut
Familial hemiplegic migraine (FHM) is a rare inherited autosomal dominant diso rder. Migraine aura may last up to several weeks and then resolve without sequel . We report a 21 year old male with FHM since the age of 3 years. Diffusion w eighted magnetic resonance imaging (DWI), perfusion MR imaging (P MRI) and [9 9 mTc] hexamethyl propyleneamine oxime single photon emission tomography (HMPA O SPECT) were performed on day 2, when he was somnolent with right sided hemipl egia, on day 9 when a mild hemiparesis was still present and on day 24 after rec overy. The right central region showed normal findings in DWI, whereas P MRI an d SPECT revealed hyperperfusion on day 2, less marked on day 9, and normal findi ngs on day 24. In conclusion, this case report indicates for the first time, by means of SPECT, P MRI and DWI studies, that even extremely long lasting migrai ne aura is not associated with cerebral ischaemia. Therefore, it supports the re vised International Headache Society criteria where the term persistentaura is proposed.
Infarction is a rare cause of spinal cord dysfunction. Whereas diffusion weighted (DW) MRI has been established as a highly sensitive technique for assessing acute cerebral ischemia, its role in spinal cord infarction remains to be determined. The purpose of this study is to present the signal characteristics of acute spinal cord ischemia using DW MRI within the first two days and after one week. MRI including DW imaging (DWI) was performed in three patients with acute spinal cord dysfunction 8, 12 and 30 hours after the onset of symptoms and repeated after one week in two patients. Two initial scans included EPI DWsequences in transverse and sagittal orientation. The remaining examinations were performed with an optimised high spatial resolution DWI sequence in the transverse plane. The diagnosis of spinal cord ischemia was established by imaging, clinical history and CSF analysis. T2 signal abnormality and restricted diffusion was demonstrated in all initial examinations. Transverse DW sequences had the highest sensitivity. The spinal infarctions were mainly located in the centre of the spinal cord and the grey matter. Contrast enhancement was absent. After one week, the restricted diffusion had normalised (pseudo normalisation) whereas the T2 signal changes had become more prominent. Restricted diffusion in the course of spinal cord ischemic infarction can be demonstrated using DW MRI. Whereas a diffusion abnormality can be found after few hours, it does not last for longer than one week. At this time, the establishment of the diagnosis has to rely mainly on T2 weighted images with additional post contrast T1 weighted images being useful.
