J Stroke.  2022 Sep;24(3):390-395. 10.5853/jos.2022.00220.

Simplified Assessment of Lesion Water Uptake for Identification of Patients within 4.5 Hours of Stroke Onset: An Analysis of the MissPerfeCT Study

• Sporns PB
• Höhne M
• Meyer L
• Krogias C
• Puetz V
• Thierfelder KM
• Duering M
• Kaiser D
• Langner S
• Brehm A
• Rotkopf LT
• Kunz WG
• Fiehler J
• Heindel W
• Schramm P
• Wiendl H
• Minnerup H
• Psychogios MN
• Kemmling A
• Minnerup J

• KMID: 2534268
• DOI: http://doi.org/10.5853/jos.2022.00220

Abstract

Background and Purpose
Many patients with stroke cannot receive intravenous thrombolysis because the time of symptom onset is unknown. We tested whether a simple method of computed tomography (CT)-based quantification of water uptake in the ischemic tissue can identify patients with stroke onset within 4.5 hours. Methods This retrospective analysis of the MissPerfeCT study (August 2009 to November 2017) includes consecutive patients with known onset of symptoms from seven tertiary stroke centers. We developed a simplified algorithm based on region of interest (ROI) measurements to quantify water uptake of the ischemic lesion and thereby quantify time of symptom onset within and beyond 4.5 hours. Perfusion CT was used to identify ischemic brain tissue, and its density was measured in non-contrast CT and related to the density of the corresponding area of the contralateral hemisphere to quantify lesion water uptake. Results Of 263 patients, 204 (77.6%) had CT within 4.5 hours. Water uptake was significantly lower in patients with stroke onset within (6.7%; 95% confidence interval [CI], 6.0% to 7.4%) compared to beyond 4.5 hours (12.7%; 95% CI, 10.7% to 14.7%). The area under the curve for distinguishing these patient groups according to percentage water uptake was 0.744 with an optimal cut-off value of 9.5%. According to this cut-off the positive predictive value was 88.8%, sensitivity was 73.5%, specificity 67.8%, negative predictive value was 42.6%. Conclusions Ischemic stroke patients with unknown time of symptom onset can be identified as being within a timeframe of 4.5 hours using a ROI-based method to assess water uptake on admission non-contrast head CT.

Keyword

Stroke; Brain ischemia; Ischemic stroke

Figure

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  Figure 1. Illustration of the method of quantification of lesion water uptake for a patients with a symptom onset <4.5 and >4.5 hours. (A) Cerebral blood volume (CBV)-map (mL/100 g) showing low CBV lesion in the right posterior cerebral artery territory. (B) A region of interest (yellow circles) is placed in the area that corresponds to the lowest CBV lesion in the non-contrast computed tomography (NCCT). Mean computed tomography (CT) attenuation in of the lesion on the ischemic side (41.7 Hounsfield unit [HU]) is divided through mean attenuation on the contralateral side (42.1 HU) indicating a quotient of 0.99 which correctly determined the patient to be inside the 4.5-hour-time window. (C) CBV-map (mL/100 g) showing low CBV lesion in the right temporal middle cerebral artery territory. (D) A region of interest (yellow circles) is placed in the area that corresponds to the lowest CBV lesion in the NCCT. Mean CT attenuation of the lesion on the ischemic side (25.9 HU) is divided through mean attenuation on the contralateral side (36.8 HU) indicating a quotient of 0.70 which correctly determined the patient to be outside the 4.5-hour-time window.

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  Figure 2. Receiver operating characteristic (ROC)-curve for identification of patients within 4.5 hours of symptom onset. AUC, area under the curve.

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  Figure 3. Cut-off 0.095 for identification of patients within 4.5 hours of symptom onset. PPV, positive predictive value; NPV, negative predictive value.

Reference

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