Whole-brain CTP in acute ischemic stroke

- Lin, Longting

Title
Whole-brain CTP in acute ischemic stroke
Creator
Lin, Longting
Relation
University of Newcastle Research Higher Degree Thesis
Resource Type
thesis
Date
2015
Description
Research Doctorate - Doctor of Philosophy (PhD)
Description
Perfusion imaging technology not only enables stroke diagnosis by identifying the ischemic lesion earlier, but also helps the clinician to make treatment decisions by further classifying the ischemic lesion into salvageable tissue and non-salvageable tissue. The imaging of salvageable tissue, penumbra, provides a direct target for reperfusion treatment. However, the accuracy of penumbra measurement with perfusion imaging has been questioned, especially with CT perfusion (CTP). Perfusion images, acquired on earlier generation instruments such as the16 or 64-detector scanners, have limited coverage of potentially ischemic brain, a factor recognised to reduce the accuracy of penumbra measurement. This limitation can be overcome by the advance in technology. The new generation “mega-detector” scanners, such as 320-detector Toshiba Aquilion One, provide whole brain coverage of 160mm from skull base to vertex. In this thesis, I presented a series of studies aiming to evaluate the utility of whole-brain CTP in acute ischemic stroke. The first study was to derive the optimal penumbra measurement on whole-brain CTP with the reference of ischemic tissue outcome, and the second study was to test the penumbra measurement of whole-brain CTP in predicting clinical patient outcome. The two studies found that only with the threshold setting at Tmax>6s or DT>3s, did the whole-brain CTP achieve high accuracy (>99%) in delineating acute ischemic penumbra and good sensitivity (>80%) in predicting favourable clinical outcome. It was also confirmed that the accuracy of penumbra measurement was comprised when the brain coverage of CTP decreased from 160mm to 20mm. Following two studies examined the utility of whole-brain CTP in the clinical setting. Firstly, CTP was compared to MRP, the perfusion modality that has already been well used in clinic. This work demonstrated that with whole brain coverage, CTP was as effective as MPR in measuring the acute penumbra and in selecting patients for reperfusion treatment. Secondly, a case by case review was carried out to assist clinicians in the interpretation CTP output. In conclusion, findings of this thesis support the usage of whole-brain CTP in acute ischemic stroke. Noticeably, the conclusion only applies to patients with anterior circulation stroke. Whole-brain CTP might also have advantage in detecting ischemic lesions in posterior circulation territory, which require studies to prove it in the future.
Subject
CT perfusion; ischemic stroke; penumbra; reperfusion
Identifier
http://hdl.handle.net/1959.13/1310399
Identifier
uon:22033
Rights
Copyright 2015 Longting Lin
Language
eng
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