Early Diffusion-weighted Magnetic Resonance Imaging Research Articles

119 Scanning Timing, Clinical Severity, and Imaging Patterns of Ultra- Early Diffusion-Weighted Magnetic Resonance Imaging in Cardiac arrest Survivors: A Multicenter Cohort Study

119 Scanning Timing, Clinical Severity, and Imaging Patterns of Ultra- Early Diffusion-Weighted Magnetic Resonance Imaging in Cardiac arrest Survivors: A Multicenter Cohort Study

Dá sa včasným pooperačným DWI zistiť reziduálny cholesteatóm?

Residual cholesteatoma results from an incomplete surgical removal of the cholesteatoma matrix. A variety of surgical procedures are used to remove cholesteatomas with varying success rates. In extensive cholesteatomas with minimal possibility of conductive system reconstruction, subtotal petrosectomy with blind sac closure is an effective surgical procedure. Diffusion-weighted magnetic resonance imaging (DWI) and ADC maps are used in the dia­gnosis of recurrent cholesteatoma. We present the case of a 40-year-old man, who repeatedly underwent revision surgeries for extensive cholesteatoma recidivism. An early postoperative DWI in the first days after the revision intervention did not show residual cholesteatoma. Surprisingly, a follow-up DWI detected the presence of cholesteatoma a few months later. The goal of this paper is to open the discussion on early postoperative DW MRI. Key words recidivism – residual and recurrent cholesteatoma – DWI – ADC map – subtotal petrosectomy – blind sac closure

Sensitivity of diffusion-weighted magnetic resonance imaging in transient global amnesia as a function of time from symptom onset.

The objective was to systematically evaluate the sensitivity of diffusion-weighted magnetic resonance imaging (DW-MRI) for transient global amnesia (TGA) across various time frames compared to the reference-standard clinical criteria. All indexed publications related to TGA and MRI through June 2020 were retrieved by a medical librarian. Two independent reviewers identified original research studies of adults with a clinical diagnosis of TGA using Caplan and Hodges and Warlow criteria (reference standard) who were evaluated with DW-MRI. Pooled estimates and its 95% confidence intervals (CI) for the proportion of acute TGA patients with positive DW-MRI (i.e., sensitivity) were obtained using random-effects meta-analysis for various time frames. Quality assessment was performed using the revised Quality of Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. After screening 665 reports, we identified 81 potentially relevant studies. Twenty-three studies representing 1688 patients met eligibility criteria, but not all studies had data available for meta-analysis. The pooled sensitivity (also described as positivity rate) of DW-MRI was 15.6% (95% CI=2.6%-35.0%) between 0 and 12h from symptom onset, 23.1% (95% CI=6.1%-45.7%) at 0-24h, 72.8% (95% CI=40.8%-96.3) at 12-24h, 68.8% (95% CI=44.8%-88.8%) at 24-36h, 72.4% (95% CI=59.8%-83.5%) at 36-48h, 82.8% (95% CI=54.7%-99.6%) at 48-60h, 66.9% (95% CI=47.5%-83.9%) at 60-72h, and 72.0% (95% CI=30.1%-100.0%) at 72-96h. There was significant concern for risk of bias in the QUADAS-2 domains of patient selection and index test, yielding a low level of certainty in the pooled estimates. DW-MRI lesions are uncommon in patients with TGA early after symptom onset, but the sensitivity (i.e., positivity rate) of DW-MRI increases with time. Despite the limited quality of existing evidence, obtaining an early DW-MRI in patients with clinical diagnosis of TGA in the acute setting is likely a low-yield test.

Lesion Patterns on Early Diffusion-weighted Magnetic Resonance Imaging and Ischemic Stroke Subtypes

Lesion Patterns on Early Diffusion-weighted Magnetic Resonance Imaging and Ischemic Stroke Subtypes

Diffusion MRI Reversibility in Ischemic Stroke Following Thrombolysis: A Meta-Analysis.

Diffusion-weighted magnetic resonance imaging (DWI) detects early infarction in acute stroke. With the substantial progress in stroke therapies, the frequency of posttreatment DWI reversibility in modern stroke cohorts is currently unknown. The purpose of this study was to perform a systematic literature review examining the relationship between characteristics of patients with ischemic stroke and DWI reversibility following treatment with lytic therapy. A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, yielding a total of 422 unique articles. Studies that were nonclinical or did not report data pertaining to DWI reversibility in the context of an acute stroke series were excluded. Characteristics regarding presentation, diagnosis, intervention, and the timing of DWI reversibility were collected for each study. After full-text review, 10 studies were identified as meeting inclusion criteria. The number of patients with DWI reversal ranged from .9% to 50%, whereas the extent of reversal ranged from 1.8% to 72.7%. Studies reporting on younger patients describe greater rates of reversibility following stroke treatment. These data suggest that early DWI signal may not represent the definitive DWI burden in recanalized populations. However, substantial heterogeneity exists regarding the rate of DWI reversal following recanalization. Additional studies are needed to elucidate the relationship among time to treatment, early reversal rates, and clinical outcomes. Physicians should use caution when basing clinical decisions on DWI lesion volumes, as these likely change to some degree with recanalization.

Early diffusion-weighted imaging and outcome prediction of comatose survivors after suicidal hanging

PurposeEarly outcome prediction after suicidal hanging is challenging in comatose survivors. We analysed the early patterns of brain diffusion-weighted magnetic resonance imaging (DWI) abnormalities in comatose survivors after suicidal hanging. MethodsAfter suicidal hanging, 18 comatose survivors were prospectively evaluated from January 2013 to December 2016. DWI was performed within 3 h after hanging in comatose survivors. We evaluated Utstein style variables and analysed abnormal spatial profile of signal intensity on DWI, brain apparent diffusion coefficient (ADC) values, and qualitative DWI scores to predict neurological outcomes. ResultsAll hanging associated cardiac arrest (CA) patients demonstrated bad neurological outcomes; 80% of non-CA comatose patients experienced good neurological outcomes. In hanging survivors with CA, cortical grey matter structures and deep grey nuclei exhibited profound ADC reductions and high DWI scores within 3 h after hanging, which was associated with diffuse anoxic brain damage with poor cerebral performance categories scores. CA comatose survivors had significantly lower ADC values and higher DWI scores compared to non-CA comatose survivors in the cortex and deep grey nuclei. ConclusionAlthough the presence of CA is the most important clinical prognosticator in hanging-associated comatose survivors, HSI abnormalities and low ADC values in the cortex and deep grey nuclei on DWI performed within 3 h after hanging are well-correlated with unfavourable outcomes regardless of therapeutic hypothermia. Therefore, early DWI may increase the sensitivity of poor outcome prediction and may be an effective combinatorial screening method when available prognostic variables are not reliable or conclusive.

Collateral Flow and Brain Changes on Computed Tomography Angiography Predict Infarct Volume on Early Diffusion-weighted Imaging

We investigated whether a computed tomography (CT)-based score could predict a large infarct (≥ 80 mL) on early diffusion-weighted magnetic resonance imaging (DWI). Acute stroke patients considered for endovascular therapy within 8 hours of the onset of symptoms were included. The Alberta Stroke Program Early Computed Tomography Score (ASPECTS) was determined on noncontrast CT and computed tomography angiography source images (CTA-SI). Limited collateral flow was defined as less than 50% collateral filling on CTA-SI. Fifty-six patients were analyzed. National Institutes of Health Stroke Scale score was 20 (15-24) in the large infarct group and 16 (11-20) in the small infarct group (P = .049). ASPECTS on noncontrast CT and CTA-SI was 5 (3-8) and 3 (2-6) in the large infarct group and 9 (8-10) and 8 (7-9) in the small infarct group (both P < .001), respectively. Limited collateral flow was frequent in the large infarct group than in the small infarct group (92% vs. 11%, P < .001). Multivariate analysis found that CTA-SI ASPECTS less than or equal to 5 (odds ratio [OR], 40.55; 95% confidence interval [CI], 1.10-1493.44; P = .044) and limited collateral flow (OR, 114.64; 95% CI, 1.93-6812.79; P = .023) were associated with a large infarct. Absence of ASPECTS less than or equal to 5 and limited collateral flow on CTA-SI predicted absence of a large infarct with a sensitivity of .89, specificity of 1.00, positive predictive value of 1.00, and negative predictive value of .71. Assessment of ASPECTS and collateral flow on CTA-SI may be able to exclude a patient with large infarct on early DWI.

Early diffusion-weighted magnetic resonance imaging in children after cardiac arrest may provide valuable prognostic information on clinical outcome

We examined whether early diffusion-weighted magnetic resonance imaging (DW-MRI) abnormalities of the brain and variation of apparent diffusion coefficient (ADC) values can provide prognostic information on clinical outcome in children following cardiac arrest (CA). Retrospective study. A 12-bed paediatric intensive care unit (PICU). Children aged between 1month and 18years who had DW-MRI with ADC measurement within the first week following CA. Neurological outcomes were assessed using the Pediatric Cerebral Performance Category Scale (PCPC). Differences between the favourable (PCPC ≤3) and unfavourable (PCPC ≥4) groups were analysed with regard to clinical data, electrophysiological patterns as well as qualitative and quantitative DW-MRI abnormalities. Twenty children with a median age of 20months (1.5-185) and a male/female sex ratio of 1.5 underwent DW-MRI after CA with a median delay of 3days (1-7). Aetiologies of CA were (i) asphyxia (n=10), (ii) haemodynamic (n=5) or (iii) unknown (n=5). With regard to DW-MRI findings, the unfavourable outcome group (n=8) was associated with cerebral cortex (p=0.02) and basal ganglia (p=0.005) lesions, with a larger number of injured brain regions (p=0.001) and a global decrease in measured ADC signal (p=0.008). Normal DW-MRI (n=5) was exclusively associated with the favourable outcome group (n=12). Qualitative, topographic and quantitative analysis of early DW-MRI with ADC measurement in children following CA may provide valuable prognostic information on neurological outcomes.

Resolution of Acute Onset Hemichorea–Hemiballismus After Treatment With Intravenous Tissue Plasminogen Activator

Hyperkinetic movement disorders are uncommon after acute ischemic stroke. Since these movement disorders are rarely the initial manifestation of acute cerebral ischemia, their presence may result in diagnostic uncertainty or it may inappropriately delay intravenous thrombolytic therapy for ischemic stroke. Hemichorea-hemiballism (HC-HB) is one of the more frequently encountered hyperkinetic movement disorders occurring in conjunction with stroke. Although HC-HB may result from a stroke mimic, the acute onset should prompt rapid evaluation and consideration for the presence of stroke along with its time-dependent therapies including recombinant tissue plasminogen activator (rtPA). In this article, we describe a case of a patient with acute cerebral ischemia presenting clinically with HC-HB, who was given intravenous rtPA therapy despite an initially negative, early diffusion-weighted magnetic resonance imaging (MRI). Follow-up brain MRI performed 24 hours after the initiation of thrombolytic therapy confirmed acute infarction in the contralateral striatum. The patient had near-complete resolution of her HC-HB on discharge and had no complications related to the administration of intravenous rtPA.

Serial brain MRI in TIA patients

Up to 40% of patients with transient ischemic attack (TIA) demonstrate lesions on diffusion-weighted magnetic resonance imaging (DWI). However, the time course of these ischemic lesions is not well known. Some lesions could vanish soon after symptom onset whereas others could be visible only after a certain delay. Based on a population of TIA patients imaged twice with DWI within the first week after onset, our aim was to estimate the rate of patients with DWI reversible ischemic lesion or with delayed DWI positivity. We retrospectively compared DWI at admission (DWI(1), median = 15 hours after TIA) with follow-up DWI (DWI(2), median = 47 hours) in 64 consecutive TIA over a 7-month period. DWI was reviewed in consensus by two readers, blinded to clinical information. Number, extent and arterial distribution of lesions were assessed. DWI(1) and DWI(2) showed similar findings in 55 TIA patients (32 with and 23 without ischemic lesions). In nine (14%) patients, changes were observed on DWI(2): presence of ischemic lesions despite normal DWI(1) (n = 3), increase in lesion size (n = 3), or partial or complete lesion reversibility (n = 3). In most TIA cases, ischemic lesions captured by early DWI and 48-hour DWI are similar. However, some ischemic lesions vanish rapidly while lesion visibility is delayed in other cases.

MRI in Patients with Acute Basilar Artery Occlusion – DWI Lesion Scoring is an Independent Predictor of Outcome

We analyzed early diffusion-weighted magnetic resonance imaging of patients with acute basilar artery occlusion by applying different lesion scoring systems and determined their predictive value for favorable outcome. Between 1998 and 2010, patients with confirmed basilar artery occlusion were entered in a local database. magnetic resonance imaging angiography was performed for diagnosis of basilar artery occlusion and/or during initiated recanalization therapy. We analyzed the patients' clinical and radiological baseline data, recanalization, and favorable outcome modified Rankin Scale 0-2 after three-months. Diffusion weighted imaging findings were categorized into lesions in vascular territories as well as by two previously published scores for ischemic damage in the posterior circulation, the Renard score and posterior circulation Acute Stroke Prognosis Early computed tomography Score. Fifty patients with basilar artery occlusion received an early MRI, and in 30 of those, a follow-up MRI was performed. Median time to baseline MRI was 5·5 h (one-hour to 24 h). Median baseline Renard score and posterior circulation Acute Stroke Prognosis Early CT Score were 2·75 (0-10) and 7 (0-10), respectively. Of the patients, 82% received an acute recanalization therapy and in 78% of those, the basilar artery recanalized. Median time to therapy was five-hours (1·25-20 h). 24% of all patients had a favorable outcome (mRS 0-2). Patients with a favorable outcome had a lower Renard score and higher pcASPECTS, a lower rate of complete basilar artery occlusion, a higher Glasgow coma scale on admission, and a higher rate of successful recanalization (all P < 0·05). After logistic regression, the only independent predictor for favorable outcome was a posterior circulation Acute Stroke Prognosis Early CT Score of 8 or more points (odds ratio 3·9, 95% confidence interval 1·4-11·7, P < 0·05). In patients with acute basilar artery occlusion, posterior circulation Acute Stroke Prognosis Early CT Score of 8 or more points on early diffusion weighted imaging is an independent predictor for favorable outcome.

Early Diffusion Weighted MRI as a Negative Predictor for Disabling Stroke After ABCD 2 Score Risk Categorization in Transient Ischemic Attack Patients

The prognostic value early diffusion-weighted magnetic resonance imaging (DWMRI) adds in the setting of transient ischemic attack (TIA), after risk stratification by a clinical score, is unclear. The purpose of this study is to evaluate, after ABCD2 score risk categorization in admitted TIA patients, whether negative DWMRI performed within 24 hours of symptom onset improves on the identification of patients at low risk for experiencing a disabling stroke within 90 days. At 15 North Carolina hospitals, we enrolled a prospective nonconsecutive sample of admitted TIA patients. We excluded patients not undergoing a DWMRI within 24 hours of admission and patients for whom a dichotomized (< or = or >3) ABCD2 score could not be calculated. We conducted a medical record review to determine disabling ischemic stroke outcomes within 90 days. Over 35 months, 944 TIA patients met inclusion criteria, of whom 4% (n=41) had a disabling ischemic stroke within 90 days. In analyses stratified by low versus moderate/high ABCD2 score, the combination of a low risk ABCD2 score and a negative early DWMRI had excellent sensitivity (100%, 95% CI 34 to 100) for identifying low-risk patients. In patients classified as moderate to high risk, a negative early DWMRI predicted a low risk of disabling ischemic stroke within 90 days (sensitivity 92%, 95% CI 80 to 97; NLR 0.11, 95% CI 0.04 to 0.32). After risk stratification by the ABCD2 score, early DWMRI enhances the prediction of a low risk for disabling ischemic stroke within 90 days. Further study is warranted in a large, consecutive TIA population of early DWMRI as a sensitive negative predictor for disabling stroke within 90 days.

Transient Ischemic Attack Etiologic Subtype and Early Risk of Stroke

To the Editor: Although clinical features help stratify stroke risk after transient ischemic attack (TIA), the novel study by Purroy et al1 on predictors of early recurrent ischemia according to etiologic subtype of the index TIA emphasizes additional variables we must consider in our prognostication algorithms. We wish to discuss some issues raised in the article which we felt merited further exploration. The study found a very low recurrent event rate in the small-vessel disease (SVD) group (1.5%, or 1 event/68 patients). Transient lacunar events due to SVD are commonly thought to have a relatively benign prognosis, and these results support such an assertion. However, in our experience, lacunar events can often progress after a seemingly transient onset, and others have shown that lacunar …