Automated Measurement of Cerebral Atrophy and Outcome in Endovascular Thrombectomy

Abstract

Background and Purpose— Methods of identifying ischemic stroke patients with a greater probability of poor outcome following endovascular thrombectomy (EVT) might improve shared treatment decision-making between patients, families, and physicians. We used an objective, automated method to measure cerebral atrophy and investigated whether this was associated with outcome in EVT patients. Methods— Consecutive EVT patients from a single-center registry were studied. CT brain scans were segmented with a combination of a validated U-Net and Hounsfield unit thresholding. Intracranial cerebrospinal fluid (CSF) volume was used as a marker of cerebral atrophy and calculated as a proportion of total intracranial volume. The primary outcome was functional independence, defined as a 3-month modified Rankin Scale score of 0 to 2. Results— Three-hundred sixty EVT patients were included. Functional independence was achieved in 204 (56.7%) patients. The mean±SD CSF volume was 9.0±4.7% of total intracranial volume. Multivariable regression demonstrated that increasing CSF volume was associated with reduced functional independence (OR=0.65 per 5% increase in CSF volume; 95% CI, 0.48–0.89; P =0.007) and higher 3-month modified Rankin Scale scores (common OR, 1.59 per 5% increase in CSF volume; 95% CI, 1.05–2.41; P =0.03). Conclusions— Cerebral atrophy determined by automated measurement of intracranial CSF volume is associated with functional outcome in patients undergoing EVT. If validated in future studies, this simple, objective, and automated imaging marker could potentially be incorporated into decision-support tools to improve shared treatment decision-making.

Response

“…We would respond that, like Schrödinger's Cat, the skull could be both at the same time. That is, greater intracranial reserve may certainly reflect cerebral atrophy and biologic aging, serving as a marker of impaired resiliency with respect to eventual functional recovery after large-vessel stroke [1]. In parallel but conversely, lower intracranial reserve was a clear marker of higher risk for malignant cerebral edema in our and two other recent studies [2][3][4].…”

Quantitative Serial CT Imaging-Derived Features Improve Prediction of Malignant Cerebral Edema after Ischemic Stroke

“…While atrophy is correlated with age, this imaging surrogate of atrophy was significantly better at distinguishing those destined for malignant edema than age alone. This biomarker, extracted automatically by our image analysis pipeline, has also been demonstrated to predict outcome after endovascular treatment for large-vessel stroke [23]. It likely captures the space available to compensate for swelling and those with more reserve are able to tolerate larger strokes with more edema before deterioration.…”

Brain atrophy predicts mortality after mechanical thrombectomy of proximal anterior circulation occlusion

“…[11][12][13][14] Furthermore, in AIS patients undergoing MT, cerebral atrophy has been linked to inferior functional outcome. [15] Moreover, brain atrophy is associated with physical frailty, [16,17] and in our previous study we showed that sarcopenia, represented by masseter muscle area and 3 density, is associated with poor three-month survival after MT. [18] The potential predictive value of BAI and its dependence on sarcopenia as well as other risk factors in AIS patients treated with MT remains poorly defined.…”