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Updated: Aug 23, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
Comparison of preperfusion and postperfusion magnetic resonance angiography in acute stroke
Salvador Pedraza1, Yolanda Silva, José Mendez
1Service of Radiology, Unidad de RM-IDI, Hospital Universitari Doctor Josep Trueta, Girona, Spain. spedraza@retemail.es
Background And Purpose:
The multimodal magnetic resonance imaging study in acute stroke includes perfusion-weighted imaging (PWI) after administration of contrast and magnetic resonance angiography (MRA). However, MRA may overestimate the degree of vessel obstruction caused by limitations to detect low flow states. Our aim was to determine the usefulness of a new fast imaging protocol combining classical MRA, PWI, and postperfusion MRA to improve the diagnostic management in acute ischemic stroke.
Methods:
We studied 31 patients with a middle cerebral artery (MCA) infarction within the first 12 hours from the onset of symptoms. All patients had an MCA stenosis or occlusion. The study protocol included a preperfusion MRA and a postperfusion MRA. Modified thrombolysis in myocardial infarction (TIMI) classification was used to assess the patency of vessels.
Results:
In 17 patients (group A, 55%), preperfusion MRA and postperfusion MRA accorded in the estimation of vascular status, whereas in 14 patients (group B, 45%) postperfusion MRA showed a better vascular flow than preperfusion MRA. The improvement in the depiction of flow was from a complete occlusion (TIMI I) to a partial occlusion (TIMI II) in 9 patients and from TIMI II to normal patency (TIMI III) in 5 patients. Thirty-six percent of the patients with suspected internal carotid artery occlusion in the preperfusion MRA showed flow in the intracranial internal carotid artery in the postperfusion MRA.
Conclusions:
Postperfusion contrast-enhanced MRA can demonstrate arterial segments with low flow and avoid overestimation of vascular obstruction.
Insights
Postperfusion MRA improves acute ischemic stroke diagnosis by better visualizing low blood flow, reducing overestimation of vessel obstruction compared to standard MRA. This enhances diagnostic accuracy for middle cerebral artery (MCA) occlusions.
Area of Science:
- Neuroradiology
- Vascular Imaging
- Stroke Diagnostics
Background:
- Multimodal MRI, including perfusion-weighted imaging (PWI) and magnetic resonance angiography (MRA), is used in acute stroke.
- Standard MRA may overestimate vessel obstruction due to limitations in detecting low flow states.
Purpose of the Study:
- To evaluate a novel fast imaging protocol combining MRA, PWI, and postperfusion MRA.
- To improve diagnostic management in acute ischemic stroke by enhancing flow assessment.
Main Methods:
- 31 patients with middle cerebral artery (MCA) infarction within 12 hours of symptom onset were studied.
- A preperfusion MRA and a postperfusion MRA were performed.
- Modified Thrombolysis In Myocardial Infarction (TIMI) classification assessed vessel patency.
Main Results:
- Postperfusion MRA revealed improved vascular flow compared to preperfusion MRA in 45% of patients.
- Improvements included transitions from complete occlusion (TIMI I) to partial occlusion (TIMI II) and to normal patency (TIMI III).
- 36% of patients with suspected carotid artery occlusion showed intracranial flow on postperfusion MRA.
Conclusions:
- Postperfusion contrast-enhanced MRA accurately demonstrates arterial segments with low flow.
- This technique helps avoid the overestimation of vascular obstruction seen with conventional MRA.
