Intracranial Cerebrospinal Fluid Volume as a Predictor of Malignant Middle Cerebral Artery Infarction

Abstract

Background and Purpose- Predicting malignant middle cerebral artery (MCA) infarction can help to identify patients who may benefit from preventive decompressive surgery. We aimed to investigate the association between the ratio of intracranial cerebrospinal fluid (CSF) volume to intracranial volume (ICV) and malignant MCA infarction. Methods- Patients with an occlusion proximal to the M3 segment of the MCA were selected from the DUST (Dutch Acute Stroke Study). Admission imaging included noncontrast computed tomography (CT), CT perfusion, and CT angiography. Patient characteristics and CT findings were collected. The ratio of intracranial CSF volume to ICV (CSF/ICV) was quantified on admission thin-slice noncontrast CT. Malignant MCA infarction was defined as a midline shift of >5 mm on follow-up noncontrast CT, which was performed 3 days after the stroke or in case of clinical deterioration. To test the association between CSF/ICV and malignant MCA infarction, odds ratios and 95% CIs were calculated for 3 multivariable models by using binary logistic regression. Model performances were compared by using the likelihood ratio test. Results- Of the 286 included patients, 35 (12%) developed malignant MCA infarction. CSF/ICV was independently associated with malignant MCA infarction in 3 multivariable models: (1) with age and admission National Institutes of Health Stroke Scale (odds ratio, 3.3; 95% CI, 1.1-11.1), (2) with admission National Institutes of Health Stroke Scale and poor collateral score (odds ratio, 7.0; 95% CI, 2.6-21.3), and (3) with terminal internal carotid artery or proximal M1 occlusion and poor collateral score (odds ratio, 7.7; 95% CI, 2.8-23.9). The performance of model 1 (areas under the receiver operating characteristic curves, 0.795 versus 0.824; P=0.033), model 2 (areas under the receiver operating characteristic curves, 0.813 versus 0.850; P<0.001), and model 3 (areas under the receiver operating characteristic curves, 0.811 versus 0.856; P<0.001) improved significantly after adding CSF/ICV. Conclusions- The CSF/ICV ratio is associated with malignant MCA infarction and has added value to clinical and imaging prediction models in limited numbers of patients.

Keywords: brain edema; humans; infarction, middle cerebral artery; odds ratio; prognosis.

Figure 1.

Gaussian mixture models fitted to noncontrast computed tomography (CT) histograms. An example of gaussian mixture models fitted to 3 noncontrast CT histograms: coarsely segmented gray matter, white matter, and cerebrospinal fluid (CSF). The solid line represents the measured intensity histogram, whereas the dashed line represents the mixture model. The mixture model consists of 3 gaussian distributions: gray matter (light gray; mean, 33.6 HU), white matter (dark gray; mean, 27.0 HU), and CSF (black; mean, 9.5 HU). Note that the gray matter histogram is dominated by the gray matter peak, the white matter histogram by the white matter peak, and the CSF histogram by both the CSF and gray matter peaks.

Figure 2.

Examples illustrating the association between the ratio of intracranial cerebrospinal fluid volume (CSF) and intracranial volume (ICV) and malignant middle cerebral artery (MCA) infarction. First example of a baseline noncontrast computed tomography (CT) image of an 81-y-old man with a large MCA infarction due to an occlusion of the proximal M1 segment (A). The ratio between intracranial CSF/ICV was 0.19. On follow-up, noncontrast CT demarcation of the infarction is visible, but no midline shift has occurred (B). Second example of a baseline noncontrast CT image of a 52-y-old woman with a large MCA infarction due to an occlusion of the proximal M1 segment (C). The CSF/ICV was 0.08. On follow-up, noncontrast CT malignant edema has developed leading to a midline shift of >5 mm (D).

Figure 3.

Performance of prediction models with and without the ratio between intracranial cerebrospinal fluid volume (CSF) and intracranial volume (ICV). Clinical prediction model (A), prediction model with clinical and imaging predictors (B), and imaging prediction model (C) with and without the ratio between intracranial CSF/ICV, respectively. Proximal occlusion indicates terminal internal carotid artery or proximal M1 occlusion. NIHSS indicates National Institutes of Health Stroke Scale; and PCS, poor collateral score.