Multimodal CT pc-ASPECTS in infratentorial stroke: diagnostic and prognostic value

Improving acute stroke assessment in non-enhanced computed tomography: automated tool for early ischemic lesion volume detection

BACKGROUND AND OBJECTIVES

ASPECTs is a widely used marker to identify early stroke signs on non-enhanced computed tomography (NECT), yet it presents interindividual variability and it may be hard to use for non-experts. We introduce an algorithm capable of automatically estimating the NECT volumetric extension of early acute ischemic changes in the 3D space. We compared the power of this marker with ASPECTs evaluated by experienced practitioner in predicting the clinical outcome.

METHODS

We analyzed and processed neuroimaging data of 153 patients admitted with acute ischemic stroke. All patients underwent a NECT at admission and on follow-up. The developed algorithm identifies the early ischemic hypodense region based on an automatic comparison of the gray level in the images of the two hemispheres, assumed to be an approximate mirror image of each other in healthy patients.

RESULTS

In the two standard axial slices used to estimate the ASPECTs, the regions identified by the algorithm overlap significantly with those identified by experienced practitioners. However, in many patients, the regions identified automatically extend significantly to other slices. In these cases, the volume marker provides supplementary and independent information. Indeed, the clinical outcome of patients with volume marker = 0 can be distinguished with higher statistical confidence than the outcome of patients with ASPECTs = 10.

CONCLUSION

The volumetric extension and the location of acute ischemic region in the 3D-space, automatically identified by our algorithm, provide data that are mostly in agreement with the ASPECTs value estimated by expert practitioners, and in some cases complementary and independent.

Post-ASPECTS and Post-PC-ASPECTS Predict the Outcome of Anterior and Posterior Ischemic Stroke Following Thrombectomy

Purpose

In this study, we aimed to determine whether post-Alberta Stroke Project Early CT Changes Score (post-ASPECTS) in anterior stroke and post-(posterior circulation) PC-ASPECTS in posterior stroke on CT can predict post-endovascular thrombectomy (EVT) functional outcomes among patients with acute ischemic stroke (AIS) after EVT.

Patients and Methods

A total of 247 consecutive patients aged 18 and over receiving EVT for LVO-related AIS were recruited into a prospective database. The data was retrospectively analyzed between March 2019 and February 2022 from two comprehensive tertiary care stroke centers: Foshan Sanshui District People's Hospital and First People's Hospital of Foshan in China. Patient parameters included EVT within 24 hr of symptom onset, premorbid modified Rankin scale (mRS) ≤2, presence of distal and terminal cerebral blood vessel occlusion, and subsequent 24-72-hr post-stroke onset CT scan. Univariate comparisons were performed using the Fisher's exact test or χ2 test for categorical variables and the Mann-Whitney U-test for continuous variables. Logistic regression analysis was performed to further analyze for adjusting for confounding factors. A p-value of ≤0.05 was statistically significant.

Results

Overall, 236 individuals with 196 anterior circulation ischemic strokes and 40 posterior strokes of basilar artery occlusion were examined. Post-ASPECTS in anterior stroke and post-pc-ASPECTS as strong positive markers of favorable outcome at 90 days post-EVT; and lower rates of inpatient mortality/hospice discharge, 90-day mortality, and 90-day poor outcome were observed. Moreover, patients in the post-ASPECTS ≥ 7 cohort experienced shorter door-to-recanalization time (DRT), puncture-to-recanalization time (PRT), and last known normal-to-puncture time (LKNPT).

Conclusion

Post-ASPECTS ≥7 in anterior circulation AIS and post-pc-ASPECTS ≥7 in posterior circulation can serve as strong prognostic markers of functional outcome after EVT.

Basilar artery occlusion: A review of clinicoradiologic features, treatment selection, and endovascular techniques

Basilar artery occlusion (BAO) is an infrequent but often fatal subtype of stroke. Predicting outcomes and selecting patients for endovascular therapy (EVT) remains challenging. Advances in neuroimaging and the development of prognostic scoring systems have augmented clinical decision-making over time. Recent randomized trials, BEST (Basilar Artery Occlusion Endovascular Intervention vs. Standard Medical Treatment), BASICS (Basilar Artery International Cooperation Study), BAOCHE (Basilar Artery Occlusion CHinese Endovascular Trial) and ATTENTION (Endovascular Treatment for Acute Basilar Artery Occlusion), compared EVT and medical management for patients with BAO. These trials yielded mixed results. The former two suggested unclear benefit while the latter two supported a benefit of EVT. While all had limitations, most providers agree caution should be exercised when excluding patients from EVT who may stand to benefit. Further studies are therefore needed to determine the effectiveness, safety, selection criteria, and optimal technical approach for EVT among patients with BAO. Hyperacute-phase advanced imaging can offer several benefits to aid decision making. It is reasonable to exclude patients with low National Institutes of Health Stroke Scale (NIHSS), large imaging-proven cores, and evidence of perforator occlusion by branch atheromatous disease. Herein, we review the clinical presentation, imaging work-up, treatments, and clinical outcomes for BAO, while highlighting knowledge gaps in treatment selection and technique.

The value of computed tomography perfusion deficit volumes in acute isolated brainstem infarction

Purpose

Diagnosis of acute isolated brainstem infarction is challenging owing to non-specific, variable symptoms, and the effectiveness of non-contrast computed tomography (NCCT) is poor owing to limited spatial resolution and artifacts. Computed tomography perfusion (CTP) imaging parameters are significantly associated with functional outcomes in posterior circulation acute ischemic stroke; however, the role of CTP in isolated brainstem infarction remains unclear. We aimed to determine the value of CTP imaging parameters in predicting functional outcomes for affected patients.

Methods

In total, 116 consecutive patients with isolated pontine/midbrain hypoperfusion who underwent CTP and follow-up by magnetic resonance imaging (MRI) between January 2018 and March 2022, were retrospectively analyzed. Perfusion deficit volumes on all maps, and the final infarction volume (FIV) on MRI were quantified. "Good" functional outcome was defined as a 90-day modified Rankin Scale score of 0 and 1. Statistical analysis included uni- and multivariate regression analyses, binary logistic regressions, and receiver operating characteristics (ROC) analyses.

Results

In total, 113 patients had confirmed isolated pontine/midbrain infarction on follow-up MRI. Onset-to-scan time, visibility of ischemic lesions on NCCT, the baseline National Institutes of Health Stroke Scale (NIHSS) score, and perfusion deficit volumes on all CTP maps were significantly associated with FIV (p < 0.05). In a multivariate linear regression model, adjusted for age, sex, NIHSS score, onset-to-scan time, and visibility of NCCT, perfusion deficit volumes remained significantly associated with FIV. In binary logistic regression analyses, perfusion deficit volumes on all CTP maps remained independent predictors of a good functional outcome. In ROC analyses, the cerebral blood flow deficit volume showed a slightly higher discriminatory value with the largest area under the curve being 0.683 [(95% CI, 0.587-0.780), p = 0.001].

Conclusion

Perfusion deficit volumes of CTP imaging could reflect the FIV and contain prognostic information on functional outcomes in patients with acute isolated brainstem infarction.

Prognostic Neuroimaging Biomarkers in Acute Vascular Brain Injury and Traumatic Brain Injury

Prognostic imaging biomarkers after acute brain injury inform treatment decisions, track the progression of intracranial injury, and can be used in shared decision-making processes with families. Herein, key established biomarkers and prognostic scoring systems are surveyed in the literature, and their applications in clinical practice and clinical trials are discussed. Biomarkers in acute ischemic stroke include computed tomography (CT) hypodensity scoring, diffusion-weighted lesion volume, and core infarct size on perfusion imaging. Intracerebral hemorrhage biomarkers include hemorrhage volume, expansion, and location. Aneurysmal subarachnoid biomarkers include hemorrhage grading, presence of diffusion-restricting lesions, and acute hydrocephalus. Traumatic brain injury CT scoring systems, contusion expansion, and diffuse axonal injury grading are reviewed. Emerging biomarkers including white matter disease scoring, diffusion tensor imaging, and the automated calculation of scoring systems and volumetrics are discussed.

Cerebral perfusion imaging predicts final infarct volume after basilar artery thrombectomy

OBJECTIVES

Cerebral perfusion imaging may be used to identify the ischemic core in acute ischemic stroke (AIS) patients with a large vessel occlusion of the anterior circulation; however, perfusion parameters that predict the ischemic core in AIS patients with a basilar artery occlusion (BAO) are poorly described. We determined which cerebral perfusion parameters best predict the ischemic core after successful endovascular thrombectomy (EVT) in BAO patients.

MATERIALS AND METHODS

We performed multicenter retrospective study of BAO patients with perfusion imaging before EVT and a DWI after successful EVT. The ischemic core was defined as regions on CTP, which were co-registered to the final DWI infarct. Various time-to-maximum (Tmax) and cerebral blood flow (CBF) thresholds were compared to final infarct volume to determine the best predictor of the final infarct.

RESULTS

28 patients were included in the analysis for this study. Tmax >8s (r²: 0.56; median absolute error, 16.0 mL) and Tmax >10s (r²: 0.73; median absolute error, 11.3 mL) showed the strongest agreement between the pre-EVT CTP study and the final DWI. CBF <38% (r²: 0.76; median absolute error, 8.2 mL) and CBF <34% (r²: 0.76; median absolute error, 9.1 mL) also correlated well with final infarct volume on DWI.

CONCLUSIONS

Pre-EVT CT perfusion imaging is useful to predict the final ischemic infarct volume in BAO patients. Tmax >8s and Tmax >10s were the strongest predictors of the post-EVT final infarct volume.

Enteral Nutrition and Hydration in Patients with Acute Stroke: Efficacy of an Automatic Pump System for Water Administration and Flushes-A Pilot Study

BACKGROUND

Enteral nutrition is often prescribed in acute stroke to meet energy and fluid needs in patients with dysphagia. Tubes clogging represent a common complication of enteral formula delivery, requiring substitution and influencing nutrition administration. Frequent water flushes are recommended as one of the most effective procedures to prevent tube occlusion, but it might be time demanding and not consistently performed by the healthcare staff. This study aimed to assess the efficacy of an automatic flush pump, compared to a manual flush system, to prevent tubes' occlusions in acute-stroke patients, as this might affect nutrition and hydration.

METHODS

Gastrointestinal symptoms, nutrition and hydration biomarkers were also monitored to determine the different devices' safety. Sixty-two patients were included in the study and allocated to the "manual" or "automatic" flushes device.

RESULTS

The mean duration of data collection was 7 ± 2 days. Tube occlusions occurred in 22.6% of the patients in the "manual" group, whereas only one tube clogging was reported in the "automatic" group (p = 0.023). No significant differences between groups were reported for constipation and diarrhea frequency nor nutrition and hydration status. When the nurses were asked to simulate manual flush administration at the same frequency of the automatic device, they were able to meet the recommendations only 10% of the time.

CONCLUSION

This preliminary study suggests the efficacy of automatic flush systems to prevent enteral tube clogging, without affecting health status compared to standard manual flush systems.

Incremental value of Alberta Stroke Program Early CT Score to collateral score for predicting target mismatch in stroke patients with extended time window or unknown onset time

PURPOSE

To evaluate whether Alberta Stroke Program Early CT Score (ASPECTS) could provide incremental value to collateral score, and their integration could be an effective surrogate of CTP in predicting target mismatch.

MATERIAL AND METHODS

One hundred and fifty-nine stroke patients (onset time 6-16 h or with unknown onset time) with MCA and/or ICA occlusion underwent non-contrast computed tomography (NCCT) and CT perfusion (CTP) scan for initial assessment. Simulated single-phase CT angiography (sCTA, peak arterial phase) and multiphase CTA (mCTA) were reconstructed from CTP. ASPECTS was assessed on NCCT and sCTA. Collateral score was evaluated on mCTA. Target mismatch was defined as infarct core volume < 70 mL, the mismatch ratio ≥ 1.8, and the absolute mismatch volume ≥ 15 mL. Pearson correlation analysis, Mann-Whitney U test, chi-square test, and receiver operating characteristic curve analyses were performed.

RESULTS

Median CTA source image (CTA-SI) ASPECTS was significantly lower than NCCT ASPECTS (p = 0.001). NCCT ASPECTS, CTA-SI ASPECTS, and mCTA collateral score correlated significantly with infarct core volume and mismatch ratio (all p < 0.05). Mismatch group showed significantly higher NCCT ASPECTS, CTA-SI ASPECTS, and mCTA collateral score than non-mismatch group (all p < 0.001). NCCT ASPECTS and CTA-SI ASPECTS showed comparable predicting performance with mCTA collateral score (p > 0.05). Adding CTA-SI ASPECTS to mCTA collateral score improved the performance of mCTA in predicting target mismatch (area under curve, 0.905 vs. 0.804, p = 0.003).

CONCLUSION

ASPECTS can provide incremental information to collateral score in predicting target mismatch. If CTP scan fails, clinical decision based on ASPECTS and collateral score might be reasonable.