What is the role of neuroimaging in the treatment of stroke?

Updated: Nov 30, 2018
  • Author: Andrew Danziger; Chief Editor: L Gill Naul, MD  more...
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Current treatments for acute ischemic stroke include intravenous thrombolytic therapy with tPA and endovascular therapies, including intraarterial thrombolytic therapy and clot retrieval devices. Surgical management with hemispheric decompression in patients with middle cerebral artery territory infarction and associated life-threatening parenchymal edema has also been supported. [5, 112]

Advanced neuroimaging with diffusion and perfusion imaging may then serve an important role in identifying potentially salvageable tissue at risk and guiding clinical decision making regarding therapy. [13, 113, 114, 115] In acute ischemic stroke, brain tissue that has been irreversibly damaged is called the infarct core, whereas the tissue that is reversibly damaged is called penumbra. In order to save penumbra, blood flow to the area must be restored before irreversible damage occurs. When determining the management of acute ischemic stroke, the physician must consider if the benefit of saving penumbra outweighs the risk of hemorrhagic conversion into an infarct core. For example, the most favorable conditions for reperfusion therapy is one with a large penumbra and small infarct core, since the benefit of saving a significant amount of brain tissue outweighs the small risk of hemorrhagic conversion. Therefore, a need to quantify and distinguish penumbra and infarct core is essential to the management. Perfusion imaging studies have shown to be useful in this distinction. For example, one study evaluating the usefulness of CT perfusion in acute ischemic stroke found that a delayed time to the peak of residual function (DT) greater than 2 seconds in addition to a CBF < 40% accurately represents infarct core, whereas those with a CBF >40% accurately defines penumbra. [116] However, further research is needed for standardization. 

Newer stroke trials have shown the benefit of using neuroimaging to select the patients who are most likely to benefit from thrombolytic therapy and the potential benefits of extending the window for thrombolytic therapy beyond previous guidelines.

The Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution (DEFUSE) trial demonstrated the benefit of administering IV tPA within 3-6 hours of stroke onset in patients with small ischemic cores on DWI and larger perfusion abnormalities (large ischemic penumbras).

Randomized trials have shown superior benefit of combining endovascular mechanical thrombectomy with IV rtPA versus rtPA alone. [117]

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