Diagnosing acute lacunar infarction using CT perfusion

doi:10.1016/j.jocn.2016.01.001

Journal of Clinical Neuroscience

Volume 29, July 2016, Pages 70-72

https://doi.org/10.1016/j.jocn.2016.01.001 Get rights and content

Highlights

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CT perfusion (CTP) identifies large vessel ischemic stroke with high sensitivity.
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We examined sensitivity for lacunar infarction (single perforating vessel occlusion).
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CTP abnormalities were identified in 56% of lacunar stroke patients.
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Mean transit time (MTT) was the most sensitive map type.
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Recognition of CTP abnormalities in lacunar stroke may improve diagnostic confidence.

Abstract

The value of CT perfusion (CTP) in detecting acute lacunar infarcts (LACI) has not been well established. We tested the sensitivity of CTP for LACI. CTP maps of consecutive stroke patients from 2009–2013 were examined. MRI diffusion imaging was used to identify those with LACI. Two stroke neurologists independently evaluated the CTP maps for evidence of a perfusion lesion in a deep perforating artery territory. Cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT) and time to maximum (Tmax) maps were first examined in isolation and then in combination. Inter-observer agreement was measured using Cohen’s κ. The lesions identified were later confirmed against the diffusion MRI reference and the sensitivity and specificity of CTP maps calculated. A total of 63 patient scans were analysed. There were 32 patients with MRI-confirmed LACI within the coverage of CTP; 18 in the striatum, 10 thalamic, and four in the corona radiata. Another 31 patients had normal MRI. Inter-rater agreement was good (κ = 0.83). Sensitivity (blinded consensus) was highest for MTT (56.2%) compared to Tmax (25%, p < 0.001), CBV (9.3%, p = 0.021) and CBF (43.7%, p < 0.001). MTT maps enable detection of a significant proportion of LACI using CTP.

Introduction

Lacunar infarction (LACI) is presumed to be caused by occlusion of a single perforator artery and is commonly located within the internal capsule, striatum, corona radiata or thalamus [1]. Diffusion MRI has excellent sensitivity for LACI but is not readily accessible for acute stroke patients in many centres and is contraindicated in some cases (for example, those with metallic implants). CT perfusion (CTP) has advantages in accessibility but previous studies have found approximately 50% of false negative cases could be attributed to LACI [2], [3].

We studied the diagnostic accuracy of CTP obtained within 9 hours of stroke onset for the detection of LACI in a retrospective cohort of patients presenting with suspected acute ischemic stroke.

Section snippets

Patients

Patients presenting to The Royal Melbourne Hospital, Australia, with suspected acute ischemic stroke within 9 hours of onset had baseline multimodal CT scan and follow-up MRI diffusion weighted imaging (DWI) within 48 hours as part of routine care. Patients were diagnosed with lacunar infarction based on follow-up DWI (see below). Patients were excluded if they had large artery occlusion on CT angiography, cortical CTP lesions, DWI lesions outside CTP coverage, or poor CTP imaging data quality.

Results

There were 32 patients with MRI-confirmed lacunar stroke within CTP coverage (18 striatal, 10 thalamic and four corona radiata). Median age was 70 years (interquartile range [IQR] 56–79), 68% were male, 72% presented <4.5 hours after onset and 50% received intravenous tissue-plasminogen-activator after imaging. There were 31 patients with transient ischaemic attack or stroke mimics who had normal DWI with a median age of 62 years (IQR 42–71).

In blinded analysis of single maps, inter-rater

Discussion

This study found that CTP was able to detect a substantial proportion of acute lacunar infarcts with good inter-rater reliability. MTT was the most sensitive map and reviewing multiple maps did not appear to increase sensitivity further.

Many centres use time to peak (TTP) or Tmax as the primary perfusion map for identification of ischemia. These delay-based maps are highly sensitive to large vessel occlusion and collateral blood flow. However, in lacunar infarction, there is no macrovascular

Conflicts of Interest/Disclosures

The authors declare that they have no financial or other conflicts of interest in relation to this research and its publication.

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NCCT and CTA enable the exclusion of intracerebral hemorrhage and the detection of vessel occlusion. CTP imaging aids in the diagnosis of acute cerebral infarct early and accurately and facilitates treatment decisions by the estimation of an irreversible infarct core and reversible penumbra [1–4]. However, NCCT, brain CTP, and head-and-neck CTA are only performed separately with 2 adequate doses of contrast injection due to the limitation of scanner capability, resulting in increased imaging time and contrast dosage.
We sought to evaluate the performance of a new “one-stop-shop” scan protocol combining brain computed tomography perfusion (CTP) and head-and-neck CT angiography (CTA) imaging for acute stroke patients using a 256-detector CT scanner.
From March to August 2020, 60 patients (30 men and 30 women) aged 22–88 years with suspected acute stroke were enrolled and randomly divided into 2 groups to undergo brain CTP and head-and-neck CTA with a 256-detector CT system. Group A used traditional scan protocol with a separate brain CTP and head-and-neck CT examination that included non–contrast-enhanced and contrast-enhanced acquisitions; group B used the new “one-stop-shop” scan protocol with head-and-neck CTA data inserted into brain CTP scans at the peak time (PT) of the arterial phase. The insertion point of the head-and-neck CTA data was determined by a test bolus. The examination time, contrast dose, radiation dose, and image quality were compared between the groups.
The total contrast dose was reduced by 40% in group B compared to group A (60 mL vs. 100 mL). The imaging time was 52.5 ± 2.6 s in group B and 74.9 ± 3.3 s in group A, showing a reduction of approximately 43% in group B. There was no significant difference in image quality both quantitatively and qualitatively between the groups (all P > 0.05). Group B had a slight reduction in dose length product (1139.0 ± 45.3 vs. 1211.6 ± 31.9 mGy·cm, P < 0.001).
The proposed “one-stop-shop” scan protocol combining brain CTP and head-and-neck CTA on a 256-detector CT system can reduce imaging time and contrast dose, without affecting image quality or perfusion results, compared to the traditional protocol of separating the examinations.
Extending thrombolysis to 4·5–9 h and wake-up stroke using perfusion imaging: a systematic review and meta-analysis of individual patient data
2019, The Lancet
Citation Excerpt :
However, patients with lacunar stroke would not meet perfusion mismatch criteria, but were found to benefit from thrombolysis in WAKE-UP.23 CT perfusion can identify around 50% of patients with lacunar stroke,24 but no data are available on thrombolysis of lacunar stroke more than 4·5 h from stroke onset based on CT perfusion. The trials included in this meta-analysis were largely done before the publication of evidence supporting endovascular thrombectomy in patients with large vessel occlusion 6–24 h after stroke onset.
Stroke thrombolysis with alteplase is currently recommended 0–4·5 h after stroke onset. We aimed to determine whether perfusion imaging can identify patients with salvageable brain tissue with symptoms 4·5 h or more from stroke onset or with symptoms on waking who might benefit from thrombolysis.
In this systematic review and meta-analysis of individual patient data, we searched PubMed for randomised trials published in English between Jan 1, 2006, and March 1, 2019. We also reviewed the reference list of a previous systematic review of thrombolysis and searched ClinicalTrials.gov for interventional studies of ischaemic stroke. Studies of alteplase versus placebo in patients (aged ≥18 years) with ischaemic stroke treated more than 4·5 h after onset, or with wake-up stroke, who were imaged with perfusion-diffusion MRI or CT perfusion were eligible for inclusion. The primary outcome was excellent functional outcome (modified Rankin Scale [mRS] score 0–1) at 3 months, adjusted for baseline age and clinical severity. Safety outcomes were death and symptomatic intracerebral haemorrhage. We calculated odds ratios, adjusted for baseline age and National Institutes of Health Stroke Scale score, using mixed-effects logistic regression models. This study is registered with PROSPERO, number CRD42019128036.
We identified three trials that met eligibility criteria: EXTEND, ECASS4-EXTEND, and EPITHET. Of the 414 patients included in the three trials, 213 (51%) were assigned to receive alteplase and 201 (49%) were assigned to receive placebo. Overall, 211 patients in the alteplase group and 199 patients in the placebo group had mRS assessment data at 3 months and thus were included in the analysis of the primary outcome. 76 (36%) of 211 patients in the alteplase group and 58 (29%) of 199 patients in the placebo group had achieved excellent functional outcome at 3 months (adjusted odds ratio [OR] 1·86, 95% CI 1·15–2·99, p=0·011). Symptomatic intracerebral haemorrhage was more common in the alteplase group than the placebo group (ten [5%] of 213 patients vs one [<1%] of 201 patients in the placebo group; adjusted OR 9·7, 95% CI 1·23–76·55, p=0·031). 29 (14%) of 213 patients in the alteplase group and 18 (9%) of 201 patients in the placebo group died (adjusted OR 1·55, 0·81–2·96, p=0·66).
Patients with ischaemic stroke 4·5–9 h from stroke onset or wake-up stroke with salvageable brain tissue who were treated with alteplase achieved better functional outcomes than did patients given placebo. The rate of symptomatic intracerebral haemorrhage was higher with alteplase, but this increase did not negate the overall net benefit of thrombolysis.
None.
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CT Perfusion in Lacunar Stroke: A Systematic Review
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Clinical StudyDiagnosing acute lacunar infarction using CT perfusion

Highlights

Abstract

Introduction

Section snippets

Patients

Results

Discussion

Conflicts of Interest/Disclosures

Subcortical infarction – classification and terminology

Cerebrovasc Dis

Perfusion ct improves diagnostic accuracy for hyperacute ischemic stroke in the 3-hour window: study of 100 patients with diffusion mri confirmation

Cerebrovasc Dis

CT perfusion improves diagnostic accuracy and confidence in acute ischaemic stroke

J Neurol Neurosurg Psychiatry

Real-time diffusion-perfusion mismatch analysis in acute stroke

J Magn Reson Imaging

Clinical Study
Diagnosing acute lacunar infarction using CT perfusion