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delayed_cerebral_ischemia_diagnosis

Delayed cerebral ischemia diagnosis

Evaluating the proportion of the brain with critical hypoperfusion after SAH may better capture the extent of DCI than averaging CBF across heterogenous brain regions 1).

Early low CBF measurements and a high lactate and lactate to pyruvate ratio may be early warning signs of the risk of developing Delayed cerebral ischemia (DCI). The clinical value of these findings needs to be confirmed in larger studies 2).

Transcranial Doppler (TCD) and transcranial color-coded duplex sonography (TCCS) are noninvasive modalities that can be used to assess vasospasm. However, high flow velocity does not always reflect DCI.

Significant literature shows that perfusion computed tomography (CTP) can provide sufficient information on cerebral hemodynamics and effectively indicate delayed cerebral ischemia (DCI) before the development of infarction. Sun et al. aimed at performing a meta-analysis to provide a more full and accurate evaluation of CTP and CTP parameters in detecting DCI in patients with aneurysmal subarachnoid hemorrhage.

In the PubMed, MedLine, Embase and Cochrane databases analysis published from February 2005 to February 2013. The extraction of CTP parameters, including cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), time to peak (TTP), interhemispheric ratios for CBV and CBF and interhemispheric differences for MTT and TTP. Pooled estimates of sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and the summary receiver-operating characteristic curve were determined.

Four research studies are met the inclusion criteria for the analysis. The pooled sensitivity, specificity, PLR, NLR and DOR of CTP for detecting the DCI were 82%, 82%, 4.56, 0.22 and 20.96, respectively. Through the evaluation of absolute CTP parameters, CBF and MTT showed diagnostic value for DCI, but CBF and TTP did not. Moreover, CBF ratio, MTT difference and TTP difference showed more diagnostic value than CBV ratio in DCI detection by the assessment of relative CTP parameters.

As a non-invasive and short time consuming screening method, CTP own a high diagnostic value for the detection of DCI after aneurysm rupture 3).

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.

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.

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 4).


Whole-brain CT Perfusion (CTP) on Day 3 after aneurysmal subarachnoid hemorrhage (aSAH) allows early and reliable identification of patients at risk for delayed ischemic neurological deficits (DIND) and tissue at risk for delayed cerebral infarction (DCI) 5).


The association between alpha-delta ratio (ADR) on quantitative electroencephalography (EEG) and DCI has been reported in several previous studies, but their results are conflicting 6).

1)
Jafri H, Diringer MN, Allen M, Zazulia AR, Zipfel GJ, Dhar R. Burden of cerebral hypoperfusion in patients with delayed cerebral ischemia after subarachnoid hemorrhage. J Neurosurg. 2019 May 31:1-8. doi: 10.3171/2019.3.JNS183041. [Epub ahead of print] PubMed PMID: 31151110.
2)
Rostami E, Engquist H, Howells T, Johnson U, Ronne-Engström E, Nilsson P, Hillered L, Lewén A, Enblad P. Early low cerebral blood flow and high cerebral lactate: prediction of delayed cerebral ischemia in subarachnoid hemorrhage. J Neurosurg. 2017 Jun 2:1-9. doi: 10.3171/2016.11.JNS161140. [Epub ahead of print] PubMed PMID: 28574309.
3)
Sun H, Zhang H, Ma J, Liu Y, Wang K, You C. Accuracy of computed tomography perfusion in detecting delayed cerebral ischemia following aneurysmal subarachnoid hemorrhage: a meta-analysis. Neurol India. 2013 Sep-Oct;61(5):507-12. doi: 10.4103/0028-3886.121922. PubMed PMID: 24262454.
4)
Cremers CH, Dankbaar JW, Vergouwen MD, Vos PC, Bennink E, Rinkel GJ, Velthuis BK, van der Schaaf IC. Different CT perfusion algorithms in the detection of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage. Neuroradiology. 2015 Jan 23. [Epub ahead of print] PubMed PMID: 25614332.
5)
Malinova V, Dolatowski K, Schramm P, Moerer O, Rohde V, Mielke D. Early whole-brain CT perfusion for detection of patients at risk for delayed cerebral ischemia after subarachnoid hemorrhage. J Neurosurg. 2015 Dec 18:1-9. [Epub ahead of print] PubMed PMID: 26684786.
6)
Yu Z, Wen D, Zheng J, Guo R, Li H, You C, Ma L. The predictive accuracy of alpha-delta ratio on quantitative electroencephalography for delayed cerebral ischemia in patients with aneurysmal subarachnoid hemorrhage: a meta-analysis. World Neurosurg. 2019 Feb 27. pii: S1878-8750(19)30493-0. doi: 10.1016/j.wneu.2019.02.082. [Epub ahead of print] PubMed PMID: 30825635.
delayed_cerebral_ischemia_diagnosis.txt · Last modified: 2019/06/04 08:25 by administrador