Penumbra pattern assessment in acute stroke patients: comparison of quantitative and non-quantitative methods in whole brain CT perfusion

Cost-effectiveness of short-protocol emergency brain MRI after negative non-contrast CT for minor stroke detection

Objectives

To investigate the cost-effectiveness of supplemental short-protocol brain MRI after negative non-contrast CT for the detection of minor strokes in emergency patients with mild and unspecific neurological symptoms.

Methods

The economic evaluation was centered around a prospective single-center diagnostic accuracy study validating the use of short-protocol brain MRI in the emergency setting. A decision-analytic Markov model distinguished the strategies “no additional imaging” and “additional short-protocol MRI” for evaluation. Minor stroke was assumed to be missed in the initial evaluation in 40% of patients without short-protocol MRI. Specialized post-stroke care with immediate secondary prophylaxis was assumed for patients with detected minor stroke. Utilities and quality-of-life measures were estimated as quality-adjusted life years (QALYs). Input parameters were obtained from the literature. The Markov model simulated a follow-up period of up to 30 years. Willingness to pay was set to $100,000 per QALY. Cost-effectiveness was calculated and deterministic and probabilistic sensitivity analysis was performed.

Results

Additional short-protocol MRI was the dominant strategy with overall costs of $26,304 (CT only: $27,109). Cumulative calculated effectiveness in the CT-only group was 14.25 QALYs (short-protocol MRI group: 14.31 QALYs). In the deterministic sensitivity analysis, additional short-protocol MRI remained the dominant strategy in all investigated ranges. Probabilistic sensitivity analysis results from the base case analysis were confirmed, and additional short-protocol MRI resulted in lower costs and higher effectiveness.

Conclusion

Additional short-protocol MRI in emergency patients with mild and unspecific neurological symptoms enables timely secondary prophylaxis through detection of minor strokes, resulting in lower costs and higher cumulative QALYs.

Key Points

• Short-protocol brain MRI after negative head CT in selected emergency patients with mild and unspecific neurological symptoms allows for timely detection of minor strokes.

• This strategy supports clinical decision-making with regard to immediate initiation of secondary prophylactic treatment, potentially preventing subsequent major strokes with associated high costs and reduced QALY.

• According to the Markov model, additional short-protocol MRI remained the dominant strategy over wide variations of input parameters, even when assuming disproportionally high costs of the supplemental MRI scan.

Drip and ship for mechanical thrombectomy within the Neurovascular Network of Southwest Bavaria

Objective

To determine feasibility and safety of stroke care organization within our Neurovascular Network of Southwest Bavaria (NEVAS) in a rural area with distances of up to 100 kilometers, we compared patients who underwent mechanical thrombectomy (MT) in large vessel occlusion admitted directly to our center (direct to center [DTC]) to patients who were transferred for MT via NEVAS (drip and ship [DS]).

Methods

This is a retrospective analysis of prospectively collected data of all MT patients between January 2015 and May 2018. Successful recanalization was defined as a thrombolysis in cerebral infarction score of 2b-3. Symptomatic intracerebral hemorrhage (sICH) was defined according to European Cooperative Acute Stroke Study 3. Modified Rankin Scale (mRS) score of 0–2 at 3 months indicated good outcome.

Results

MT was performed in 410 patients: 221 DTC and 189 DS. Median NIH Stroke Scale (NIHSS) score was 16 and premorbid mRS score was 0. Thrombolysis was applied in 62.2% with the same time from symptom onset in both groups (94.5 vs 95 minutes). Successful recanalization (79.3% vs 77.8%) and NIHSS score reduction from admission to discharge (16–7 vs 17–6) were comparable. Time delay from onset to revascularization was 96 minutes in DS (212 vs 308 minutes, p = 0.001). At follow-up, DTC patients had a trend to better outcome (33.5% vs 24.3%, p = 0.056). Neither sICH (6.3% vs 5.9%, p = 0.840) nor mortality (31.2% vs 34.4%, p = 0.387) differed between the groups.

Conclusion

DS patients benefit from MT without relevant safety concerns, but with a trend to unfavorable outcome compared to DTC patients. These results suggest that DS is suitable to provide MT in rural areas where DTC is not possible.

Middle Meningeal Artery Embolization as Treatment for Chronic Subdural Hematoma: A Case Series

BACKGROUND

Traditional treatment for symptomatic subdural hematoma (SDH) has been surgical evacuation, but recurrence rates are high and patients often harbor complex medical comorbidities. Growth and recurrence is thought to be due to the highly friable nature of the vascularized membrane that forms after initial injury. There have been reported cases of middle meningeal artery (MMA) embolization for treatment of recurrent SDH after surgical evacuation with the goal of eliminating the arterial supply to this vascularized membrane.

OBJECTIVE

To present the first known case series of MMA embolization as upfront treatment for symptomatic chronic SDHs that have failed conservative management in lieu of surgical evacuation.

METHODS

Five patients with symptomatic chronic SDHs underwent MMA embolization using PVA microparticles at our institution. Size of SDH was recorded in maximum diameter and total volume.

RESULTS

Four patients underwent unilateral and 1 underwent bilateral MMA embolization successfully. All cases had significant reduction in total volume of SDH at longest follow-up scan: 81.4 to 13.8 cc (7 wk), 48.5 to 8.7 cc (3 wk), 31.7 and 88 to 0 and 17 cc (14 wk, bilateral), 79.3 to 24.2 cc (8 wk), and 53.5 to 0 cc (6 wk). All patients had symptomatic relief with no complications. Histologic analysis of the chronic SDH membrane in a separate patient that required surgery revealed rich neovascularization with many capillaries and few small arterioles.

CONCLUSION

MMA embolization could present a minimally invasive and low-risk initial treatment alternative to surgery for symptomatic chronic SDH when clinically appropriate.

Addressing a real-life problem: treatment with intravenous thrombolysis and mechanical thrombectomy in acute stroke patients with an extended time window beyond 4.5 h based on computed tomography perfusion imaging

BACKGROUND AND PURPOSE

Acute ischemic stroke treatment with intravenous thrombolysis (IVT) is restricted to a time window of 4.5 h after known or presumed onset. Recently, magnetic resonance imaging-guided treatment decision-making in wake-up stroke (WUS) was shown to be effective. The aim of this study was to determine the safety and outcome of IVT in patients with a time window beyond 4.5 h selected by computed tomography perfusion (CTP) imaging.

METHODS

We analyzed all consecutive patients last seen well beyond 4.5 h after stroke onset treated with IVT based on CTP between January 2015 and October 2018. CTP was visually assessed to estimate the mismatch between cerebral blood flow and cerebral blood volume maps. Early infarct signs were documented according to Alberta Stroke Program Early CT Score (ASPECTS). Safety data were obtained for mortality and symptomatic intracerebral hemorrhage (sICH). Follow-up was assessed with the modified Rankin Scale (mRS).

RESULTS

A total of 70 patients fulfilled the inclusion criteria (mean age ± SD 77.6 ± 11.5 years, 50.0% female). Median National Institutes of Health Stroke Scale score on admission was 8.0 [interquartile range (IQR), 4-14]. The most frequent reasons for an extended time window were WUS (60.0%) and delayed hospital admission (27.1%). Median time from last seen well to IVT was 11.4 h. Median ASPECTS was 10 (IQR, 9-10) and CTP mismatch 90% (IQR, 80%-100%). A total of 24 patients (34.3%) underwent additional mechanical thrombectomy. sICH occurred in four patients (5.7%). At follow-up, 49.3% had an mRS score of 0-2 and 22.4% had an mRS score of 0-1.

CONCLUSIONS

In patients presenting in an extended time window beyond 4.5 h, IVT treatment with decision-making based on CTP might be a safe procedure. Further evaluation in clinical trials is needed.

Differential Benefit of Collaterals for Stroke Patients Treated with Thrombolysis or Supportive Care : A Propensity Score Matched Analysis

PURPOSE

Leptomeningeal collaterals can slow down infarction growth; however, despite good collaterals in the DAWN and DEFUSE 3 trials, outcomes were devastating if reperfusion was not attempted. The aim of this study was to compare the influence of collaterals on morphological and functional outcome in patients with acute middle cerebral artery (MCA) stroke undergoing intravenous thrombolysis (IVT) vs. supportive care (non-IVT).

METHODS

Out of 1639 consecutive patients examined with multiparametric computed tomography (CT) for suspected ischemic stroke, all patients with confirmed MCA stroke who did not undergo endovascular thrombectomy were selected. Propensity score matching (PSM) was used to match IVT and non-IVT treated patients for potential confounders including age, sex, National Institutes of Health Stroke Scale (NIHSS) score on admission, Alberta Stroke Program Early CT Score (ASPECTS), and occlusion site. Regression analysis after PSM was performed to identify independent associations.

RESULTS

After PSM, 90 IVT patients were matched with 90 non-IVT patients. In multivariable regression analysis, a high regional leptomeningeal collateral (rLMC) score was independently associated with lower final infarction volume (FIV) in the IVT group (b = -0.472, p < 0.001) but not in the non-IVT group (b = -0.116, p = 0.327). The trichotomized rLMC scores predicted functional outcome in IVT treated patients (adjusted odds ratio, aOR = 4.57, 95% confidence interval, CI, 1.03-20.32, p = 0.046) but showed no independent association with outcome in the non-IVT group (aOR = 0.69, 95% CI 0.07-6.80, p = 0.753).

CONCLUSION

Good collaterals favored smaller FIV and good functional outcome in IVT treated patients but not in non-IVT treated patients. Good collateral flow may have limited prognostic value if IVT is not administered to attempt reperfusion.

Radiological imaging in acute ischaemic stroke

Patients who suffer acute ischaemic stroke can be treated with thrombolysis if therapy is initiated early. Radiological evaluation of the intracranial tissue before such therapy can be given is mandatory. In this review current radiological diagnostic strategies are discussed for this patient group. Beyond non-enhanced computed tomography (CT), the standard imaging method for many years, more sophisticated CT stroke protocols including CT angiography and CT perfusion have been developed, and additionally an increasing number of patients are examined with magnetic resonance imaging as the first imaging method used. Advantages and challenges of the different methods are discussed.

Multimodal imaging in acute ischemic stroke

OPINION STATEMENT

Recent years have seen the development of novel neuroimaging techniques whose roles in the management of acute stroke are sometimes confusing and controversial. This may be attributable in part to a focus on establishing simplified algorithms and terminology that omit consideration of the basic pathophysiology of cerebral ischemia and, consequently, of the full potential for optimizing patients' care based upon their individual imaging findings. This review begins by discussing cerebral hemodynamic physiology and of the effects of hemodynamic disturbances upon the brain. Particular attention will be paid to the hemodynamic measurements and markers of tissue injury that are provided by common clinical imaging techniques, with the goal of enabling greater confidence and flexibility in understanding the potential uses of these techniques in various clinical roles, which will be discussed in the remainder of the review.