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Updated: Apr 18, 2026
Optimized System for Cerebral Perfusion Monitoring in the Rat Stroke Model of Intraluminal Middle Cerebral Artery Occlusion
Published on: February 17, 2013
Different CT perfusion algorithms in the detection of delayed cerebral ischemia after aneurysmal subarachnoid
Charlotte H P Cremers1, Jan Willem Dankbaar, Mervyn D I Vergouwen
1Department of Neurology and Neurosurgery, Room G03.232, Brain Center Rudolf Magnus Department of Neurology and Neurosurgery, University Medical Center Utrecht, PO Box 85500, 3508 GA, Utrecht, The Netherlands, c.h.p.cremers-2@umcutrecht.nl.
Insights
Both tracer delay-sensitive and delay-insensitive CT perfusion algorithms show similar accuracy in diagnosing delayed cerebral ischemia (DCI) after subarachnoid hemorrhage. This suggests either method is suitable for visual assessment of CTP in DCI diagnosis.
Area of Science:
- Neuroradiology
- Cerebrovascular Imaging
- Medical Diagnostics
Background:
- CT perfusion (CTP) algorithms sensitive to tracer delay can overestimate ischemia in stroke.
- Delayed contrast arrival in aneurysmal subarachnoid hemorrhage (aSAH) may also lead to overestimation of ischemia, complicating DCI diagnosis.
Purpose of the Study:
- To investigate the diagnostic accuracy of both tracer delay-sensitive and delay-insensitive CTP algorithms for detecting delayed cerebral ischemia (DCI) in aSAH patients.
Main Methods:
- Included 71 aSAH patients with clinical deterioration (excluding rebleeding) within 21 days, who underwent NCCT/CTP/CTA.
- CTP maps were generated using delay-sensitive and delay-insensitive algorithms.
- Perfusion deficits were visually assessed by two independent observers of varying experience.
Main Results:
- For experienced observers, PPVs were 0.67 (delay-sensitive) vs. 0.66 (delay-insensitive), and NPVs were 0.73 vs. 0.74.
- For less experienced observers, PPVs were 0.60 for both, and NPVs were 0.66 (delay-sensitive) vs. 0.63 (delay-insensitive).
Conclusions:
- Tracer delay-sensitive and delay-insensitive CTP algorithms demonstrate comparable test characteristics for visual DCI assessment.
- Both algorithms are suitable for diagnosing DCI in the context of aSAH.
Introduction:
Tracer delay-sensitive perfusion algorithms in CT perfusion (CTP) result in an overestimation of the extent of ischemia in thromboembolic stroke. In diagnosing delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH), delayed arrival of contrast due to vasospasm may also overestimate the extent of ischemia. We investigated the diagnostic accuracy of tracer delay-sensitive and tracer delay-insensitive algorithms for detecting DCI.
Methods:
From a prospectively collected series of aSAH patients admitted between 2007-2011, we included patients with any clinical deterioration other than rebleeding within 21 days after SAH who underwent NCCT/CTP/CTA imaging. Causes of clinical deterioration were categorized into DCI and no DCI. CTP maps were calculated with tracer delay-sensitive and tracer delay-insensitive algorithms and were visually assessed for the presence of perfusion deficits by two independent observers with different levels of experience. The diagnostic value of both algorithms was calculated for both observers.
Results:
Seventy-one patients were included. For the experienced observer, the positive predictive values (PPVs) were 0.67 for the delay-sensitive and 0.66 for the delay-insensitive algorithm, and the negative predictive values (NPVs) were 0.73 and 0.74. For the less experienced observer, PPVs were 0.60 for both algorithms, and NPVs were 0.66 for the delay-sensitive and 0.63 for the delay-insensitive algorithm.
Conclusion:
Test characteristics are comparable for tracer delay-sensitive and tracer delay-insensitive algorithms for the visual assessment of CTP in diagnosing DCI. This indicates that both algorithms can be used for this purpose.
