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Evolution of MR contrast enhancement patterns during the first week after acute ischemic stroke
J O Karonen1, P L Partanen, R L Vanninen
1Department of Clinical Radiology, Kuopio University Hospital, Finland.
Background And Purpose:
Intravascular and parenchymal enhancement have been detected with contrast-enhanced T1-weighted MR imaging in patients with ischemic stroke. Diffusion-weighted MR imaging depicts infarct within minutes after the onset of symptoms. The aims of this study were to study the different MR enhancement findings during the first week after stroke and to ascertain whether the presence of intravascular enhancement over a larger area than the infarct on diffusion-weighted images on day 1 is able to predict substantial infarct growth during the first week.
Methods:
Forty-eight patients were imaged on the first and second days and again 1 week after the onset of ischemic stroke. T1-weighted spin-echo imaging was performed before and after a 0.2 mmol/kg bolus of gadolinium chelate. Diffusion-weighted imaging was performed at the same slice positions. Enhancement findings were categorized as intravascular and parenchymal, with further categorization of parenchymal enhancement as cortical, subcortical, and deep; these findings were then compared with diffusion-weighted imaging findings.
Results:
Intravascular enhancement in the infarcted area was detected on day 1 in 78% of the cases, on day 2 in 78% of the cases, and at 1 week in 30% of the cases. Parenchymal enhancement was detected in 26%, 56%, and 100% of the cases, respectively. Intravascular enhancement over a larger area than the infarct on diffusion-weighted images on day 1 was not associated with the extent of infarct growth.
Conclusion:
Detection of different patterns of contrast enhancement can help in determining the age of infarct. Parenchymal enhancement may be intense and can cause diagnostic uncertainty in cases in which the clinical history is obscure.
Insights
Contrast-enhanced MRI reveals evolving enhancement patterns in ischemic stroke patients. While intravascular enhancement decreases, parenchymal enhancement increases over the first week, aiding infarct age determination.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Contrast-enhanced T1-weighted MRI and diffusion-weighted MRI (DWI) are used to detect changes in ischemic stroke.
- Enhancement patterns, both intravascular and parenchymal, are observed in patients with ischemic stroke.
Purpose of the Study:
- To investigate MR enhancement findings during the first week post-stroke.
- To determine if early intravascular enhancement predicts infarct growth.
Main Methods:
- 48 patients with ischemic stroke underwent MRI (T1-weighted with gadolinium and DWI) on days 1, 2, and 7.
- Enhancement patterns (intravascular and parenchymal) were categorized and compared with DWI findings.
Main Results:
- Intravascular enhancement was present in 78% on days 1 and 2, decreasing to 30% at 1 week.
- Parenchymal enhancement increased from 26% on day 1 to 100% at 1 week.
- Early intravascular enhancement did not predict infarct growth.
Conclusions:
- MR contrast enhancement patterns can help determine infarct age.
- Intense parenchymal enhancement may complicate diagnosis with obscure clinical history.