Irina Eyngorn

Prognostic value of brain diffusion-weighted imaging after cardiac arrest.

Outcome prediction is challenging in comatose postcardiac arrest survivors. We assessed the feasibility and prognostic utility of brain diffusion‐weighted magnetic resonance imaging (DWI) during the first week.

Natural History of Perihematomal Edema After Intracerebral Hemorrhage Measured by Serial Magnetic Resonance Imaging

Background and Purpose— Knowledge on the natural history and clinical impact of perihematomal edema (PHE) associated with intracerebral hemorrhage is limited. We aimed to define the time course, predictors, and clinical significance of PHE measured by serial magnetic resonance imaging. Methods— Patients with primary supratentorial intracerebral hemorrhage ≥5 cm3 underwent serial MRIs at prespecified intervals during the first month. Hematoma (Hv) and PHE (Ev) volumes were measured on fluid-attenuated inversion recovery images. Relative PHE was defined as Ev/Hv. Neurologic assessments were performed at admission and with each MRI. Barthel Index, modified Rankin scale, and extended Glasgow Outcome scale scores were assigned at 3 months. Results— Twenty-seven patients with 88 MRIs were prospectively included. Median Hv and Ev on the first MRI were 39 and 46 cm3, respectively. Median peak absolute Ev was 88 cm3. Larger hematomas produced a larger absolute Ev (r2=0.6) and a smaller relative PHE (r2=0.7). Edema volume growth was fastest in the first 2 days but continued until 12±3 days. In multivariate analysis, a higher admission hematocrit was associated with a greater delay in peak PHE (P=0.06). Higher admission partial thromboplastin time was associated with higher peak rPHE (P=0.02). Edema volume growth was correlated with a decline in neurologic status at 48 hours (81 vs 43 cm3, P=0.03) but not with 3-month functional outcome. Conclusions— PHE volume measured by MRI increases most rapidly in the first 2 days after symptom onset and peaks toward the end of the second week. The timing and magnitude of PHE volume are associated with hematologic factors. Its clinical significance deserves further study.

Yield of combined perfusion and diffusion MR imaging in hemispheric TIA

Objective: Transient ischemic attacks (TIA) predict future stroke. However, there are no sensitive and specific diagnostic criteria for TIA and interobserver agreement regarding the diagnosis is poor. Diffusion-weighted MRI (DWI) demonstrates acute ischemic lesions in approximately 30% of TIA patients; the yield of perfusion-weighted MRI (PWI) is unclear. Methods: We prospectively performed both DWI and PWI within 48 hours of symptom onset in consecutive patients admitted with suspected hemispheric TIAs of <24 hours symptom duration. Two independent raters, blinded to clinical features, assessed the presence and location of acute DWI and PWI lesions. Lesions were correlated with suspected clinical localization and baseline characteristics. Clinical features predictive of a PWI lesion were assessed. Results: Forty-three patients met the inclusion criteria. Thirty-three percent had a PWI lesion and 35% had a DWI lesion. Seven patients (16%) had both PWI and DWI lesions and 7 (16%) had only PWI lesions. The combined yield for identification of either a PWI or a DWI was 51%. DWI lesions occurred in the clinically suspected hemisphere in 93% of patients; PWI lesions in 86%. PWI lesions occurred more frequently when the MRI was performed within 12 hours of symptom resolution, in patients with symptoms of speech impairment, and among individuals younger than 60 years. Conclusions: The combination of early diffusion-weighted MRI and perfusion-weighted MRI can document the presence of a cerebral ischemic lesion in approximately half of all patients who present with a suspected hemispheric transient ischemic attack (TIA). MRI has the potential to improve the accuracy of TIA diagnosis. ACA = anterior cerebral artery; CI = confidence interval; DWI = diffusion-weighted MRI; ICA = internal carotid artery; MCA = middle cerebral artery; MRA = magnetic resonance angiography; MTT = mean transit time; OR = odds ratios; PCA = posterior cerebral artery; PWI = perfusion-weighted MRI; RR = risk ratios; TIA = transient ischemic attacks; TOAST = Trial of Org 10172 in Acute Stroke Treatment.

Temporal and spatial profile of brain diffusion-weighted MRI after cardiac arrest.

Background and Purpose— Diffusion-weighted magnetic resonance imaging of the brain is a promising technique to help predict functional outcome in comatose survivors of cardiac arrest. We aimed to evaluate prospectively the temporal-spatial profile of brain apparent diffusion coefficient changes in comatose survivors during the first 8 days after cardiac arrest. Methods— Apparent diffusion coefficient values were measured by 2 independent and blinded investigators in predefined brain regions in 18 good- and 15 poor-outcome patients with 38 brain magnetic resonance imaging scans and were compared with those of 14 normal controls. The same brain regions were also assessed qualitatively by 2 other independent and blinded investigators. Results— In poor-outcome patients, cortical structures, in particular the occipital and temporal lobes, and the putamen exhibited the most profound apparent diffusion coefficient reductions, which were noted as early as 1.5 days and reached a nadir between 3 and 5 days after the arrest. Conversely, when compared with normal controls, good-outcome patients exhibited increased diffusivity, in particular in the hippocampus, temporal and occipital lobes, and corona radiata. By qualitative magnetic resonance imaging readings, 1 or more cortical gray matter structures were judged to be moderately to severely abnormal in all poor-outcome patients except for the 3 patients imaged within 24 hours after the arrest. Conclusions— Brain diffusion-weighted imaging changes in comatose, postcardiac arrest survivors in the first week after the arrest are region and time dependent and differ between good- and poor-outcome patients. With increasing use of magnetic resonance imaging in this context, it is important to be aware of these relations.

Prognostic Value of A Qualitative Brain MRI Scoring System After Cardiac Arrest

To develop a qualitative brain magnetic resonance imaging (MRI) scoring system for comatose cardiac arrest patients that can be used in clinical practice.

A comparison of cooling techniques to treat cardiac arrest patients with hypothermia.

Introduction. We sought to compare the performance of endovascular cooling to conventional surface cooling after cardiac arrest. Methods. Patients in coma following cardiopulmonary resuscitation were cooled with an endovascular cooling catheter or with ice bags and cold-water-circulating cooling blankets to a target temperature of 32.0–34.0°C for 24 hours. Performance of cooling techniques was compared by (1) number of hourly recordings in target temperature range, (2) time elapsed from the written order to initiate cooling and target temperature, and (3) adverse events during the first week. Results. Median time in target temperature range was 19 hours (interquartile range (IQR), 16–20) in the endovascular group versus. 10 hours (IQR, 7–15) in the surface group (P = .001). Median time to target temperature was 4 (IQR, 2.8–6.2) and 4.5 (IQR, 3–6.5) hours, respectively (P = .67). Adverse events were similar. Conclusion. Endovascular cooling maintains target temperatures better than conventional surface cooling.

Magnetic Resonance Imaging Profile of Blood–Brain Barrier Injury in Patients With Acute Intracerebral Hemorrhage

Background Spontaneous intracerebral hemorrhage (ICH) is associated with blood–brain barrier (BBB) injury, which is a poorly understood factor in ICH pathogenesis, potentially contributing to edema formation and perihematomal tissue injury. We aimed to assess and quantify BBB permeability following human spontaneous ICH using dynamic contrast‐enhanced magnetic resonance imaging (DCE MRI). We also investigated whether hematoma size or location affected the amount of BBB leakage. Methods and Results Twenty‐five prospectively enrolled patients from the Diagnostic Accuracy of MRI in Spontaneous intracerebral Hemorrhage (DASH) study were examined using DCE MRI at 1 week after symptom onset. Contrast agent dynamics in the brain tissue and general tracer kinetic modeling were used to estimate the forward leakage rate (Ktrans) in regions of interest (ROI) in and surrounding the hematoma and in contralateral mirror–image locations (control ROI). In all patients BBB permeability was significantly increased in the brain tissue immediately adjacent to the hematoma, that is, the hematoma rim, compared to the contralateral mirror ROI (P<0.0001). Large hematomas (>30 mL) had higher Ktrans values than small hematomas (P<0.005). Ktrans values of lobar hemorrhages were significantly higher than the Ktrans values of deep hemorrhages (P<0.005), independent of hematoma volume. Higher Ktrans values were associated with larger edema volumes. Conclusions BBB leakage in the brain tissue immediately bordering the hematoma can be measured and quantified by DCE MRI in human ICH. BBB leakage at 1 week is greater in larger hematomas as well as in hematomas in lobar locations and is associated with larger edema volumes.

Natural history and prognostic value of corticospinal tract Wallerian degeneration in intracerebral hemorrhage.

Background The purpose of this study was to define the incidence, imaging characteristics, natural history, and prognostic implication of corticospinal tract Wallerian degeneration (CST‐WD) in spontaneous intracerebral hemorrhage (ICH) using serial MR imaging. Methods and Results Consecutive ICH patients with supratentorial ICH prospectively underwent serial MRIs at 2, 7, 14, and 21 days. MRIs were analyzed by independent raters for the presence and topographical distribution of CST‐WD on diffusion‐weighted imaging (DWI). Baseline demographics, hematoma characteristics, ICH score, and admission National Institute of Health Stroke Score (NIHSS) were systematically recorded. Functional outcome at 3 months was assessed by the modified Rankin Scale (mRS) and the motor‐NIHSS. Twenty‐seven patients underwent 93 MRIs; 88 of these were serially obtained in the first month. In 13 patients (48%), all with deep ICH, CST‐WD changes were observed after a median of 7 days (interquartile range, 7 to 8) as reduced diffusion on DWI and progressed rostrocaudally along the CST. CST‐WD changes evolved into T2‐hyperintense areas after a median of 11 days (interquartile range, 6 to 14) and became atrophic on MRIs obtained after 3 months. In univariate analyses, the presence of CST‐WD was associated with poor functional outcome (ie, mRS 4 to 6; P=0.046) and worse motor‐NIHSS (5 versus 1, P=0.001) at 3 months. Conclusions Wallerian degeneration along the CST is common in spontaneous supratentorial ICH, particularly in deep ICH. It can be detected 1 week after ICH on DWI and progresses rostrocaudally along the CST over time. The presence of CST‐WD is associated with poor motor and functional recovery after ICH.

Functional Neurologic Outcomes Change Over the First 6 Months After Cardiac Arrest.

Objectives:To determine the longitudinal changes in functional outcome and compare ordinal outcome scale assessments in comatose cardiac arrest survivors. Design:Prospective observational study of comatose cardiac arrest survivors. Subjects who survived to 1 month were included. Setting:Academic medical center ICU. Patients:Ninety-eight consecutive patients who remained comatose after resuscitation from cardiac arrest; 45 patients survived to 1 month. Interventions:None. Measurements and Main Results:Patients’ functional neurologic outcomes were assessed by phone call or in-person clinic visit at 1, 3, 6, and 12 months postcardiac arrest using the modified Rankin Scale, Glasgow Outcome Scale, and Barthel Index. A “good” outcome was defined as modified Rankin Scale 0–3, Barthel Index 70–100, and Glasgow Outcome Scale 4–5. Changes in dichotomized outcomes and shifts on each outcome scale were analyzed. The mean age of survivors was 51 ± 19 years and 18 (40%) were women. Five (19%) out of 26 patients with data available at all timepoints improved to good modified Rankin Scale outcome and none worsened to poor outcome between postarrest months 1 and 6 (p = 0.06). Thirteen patients (50%) improved on the modified Rankin Scale by 1–3 points and four (15%) worsened by 1–2 points between months 1 and 6 (overall improvement by 0.5 points; 95% CI, 0–1; p = 0.04). From postarrest months 6 to 12, there was no change in the number of patients with good versus poor outcomes. The modified Rankin Scale and Barthel Index were more sensitive to detecting changes in outcome than the Glasgow Outcome Scale. Conclusions:In initially comatose cardiac arrest survivors, improvements in functional status occur over the first 6 months after the event. There was no significant change in outcome between postarrest months 6 and 12. The modified Rankin Scale is a sensitive outcome scale in this population.

MRI guides diagnostic approach for ischaemic stroke

Background and aim Identification of ischaemic stroke subtype currently relies on clinical evaluation supported by various diagnostic studies. The authors sought to determine whether specific diffusion-weighted MRI (DWI) patterns could reliably guide the subsequent work-up for patients presenting with acute ischaemic stroke symptoms. Methods 273 consecutive patients with acute ischaemic stroke symptoms were enrolled in this prospective, observational, single-centre NIH-sponsored study. Electrocardiogram, non-contrast head CT, brain MRI, head and neck magnetic resonance angiography (MRA) and transoesophageal echocardiography were performed in this prespecified order. Stroke neurologists determined TOAST (Trial of Org 10172 in Acute Stroke Treatment) classification on admission and on discharge. Initial TOAST stroke subtypes were compared with the final TOAST subtype. If the final subtype differed from the initial assessment, the diagnostic test deemed the principal determinant of change was recorded. These principal determinants of change were compared between a CT-based and an MRI-based classification schema. Results Among patients with a thromboembolic DWI pattern, transoesophageal echocardiography was the principal determinant of diagnostic change in 8.8% versus 0% for the small vessel group and 1.7% for the other group (p<0.01). Among patients with the combination of a thromboembolic pattern on MRI and a negative cervical MRA, transoesophageal echocardiography led to a change in diagnosis in 12.1%. There was no significant difference between groups using a CT-based scheme. Conclusions DWI patterns appear to predict stroke aetiologies better than conventional methods. The study data suggest an MRI-based diagnostic algorithm that can potentially obviate the need for echocardiography in one-third of stroke patients and may limit the number of secondary extracranial vascular imaging studies to approximately 10%.