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Diffusion-weighted imaging of patients with subacute cerebral ischemia: comparison with conventional and
M Augustin1, R Bammer, J Simbrunner
1Department of Neurology, MR Institute Karl-Franzens University, Graz, Austria.
Background And Purpose:
The importance of diffusion-weighted imaging (DWI) for delineating acute ischemic lesions has been investigated extensively; however, few studies have investigated the role of DWI in the subacute stage of stroke. Because these lesions tend to appear bright throughout the first days of ischemia, owing to restricted diffusion, we speculated that DWI could also improve the detection of subacute infarcts as compared with conventional and contrast-enhanced MR imaging.
Methods:
Interleaved echo-planar DWI with phase navigation was performed on a 1.5-T MR unit in a consecutive series of 53 patients (mean age, 66 +/- 14 years) with suspected recent cerebral ischemia. The interval between onset of clinical symptoms and MR imaging ranged from 1 to 14 days (mean, 6 +/- 4 days). Contrast material was given to 28 patients in a dose of 0.1 mmol/kg.
Results:
DWI clearly delineated recent ischemic damage in 39 patients (74%) as compared with 33 (62%) in whom lesions were identified or suspected on conventional T2-weighted images. DWI provided information not accessible with T2-weighted imaging in 17 patients when evidence of lesion multiplicity or detection of clinically unrelated recent lesions was included for comparison. Subacute ischemic lesions were also seen more frequently on DWI sequences than on contrast-enhanced images (20 versus 13 patients). DWI was more likely to make a diagnostic contribution in the first week of stroke and in patients with small lesions or preexisting ischemic cerebral damage than was conventional MR imaging.
Conclusion:
Recent ischemic damage is better shown on DWI sequences than on conventional and contrast-enhanced MR images throughout the first days after stroke and may provide further information about the origin of clinical symptoms. Adding DWI to imaging protocols for patients with subacute cerebral ischemia is recommended.
Insights
Diffusion-weighted imaging (DWI) significantly improves the detection of subacute stroke lesions compared to conventional MRI. This advanced technique enhances visualization of ischemic damage in the crucial first week post-stroke.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Diffusion-weighted imaging (DWI) is established for acute stroke, but its utility in the subacute stage is less explored.
- Subacute ischemic lesions often exhibit restricted diffusion, suggesting DWI's potential for improved detection.
Purpose of the Study:
- To evaluate the effectiveness of DWI in detecting subacute cerebral infarcts.
- To compare DWI's diagnostic performance against conventional and contrast-enhanced MRI in the subacute stroke phase.
Main Methods:
- 53 patients with suspected recent cerebral ischemia underwent interleaved echo-planar DWI on a 1.5-T MR unit.
- Imaging was performed 1-14 days post-symptom onset; 28 patients received contrast material.
- Phase navigation was used to mitigate motion artifacts.
Main Results:
- DWI delineated ischemic damage in 74% of patients, surpassing conventional T2-weighted imaging (62%).
- DWI identified additional lesions or multiplicity in 17 patients, information not available with T2-weighted imaging.
- Subacute lesions were more frequently detected on DWI (20 patients) than contrast-enhanced MRI (13 patients).
Conclusions:
- DWI sequences offer superior visualization of recent ischemic damage compared to conventional and contrast-enhanced MRI in the early days post-stroke.
- DWI may provide crucial information regarding the origin of clinical symptoms in subacute stroke.
- Incorporating DWI into imaging protocols for subacute cerebral ischemia is recommended.