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Aim: Magnetic Resonance Imaging (MRI) is an important prognostic tool in cardiac arrest (CA) survivors given its sensitivity for detecting hypoxic-ischemic brain injury (HIBI), however, it is limited by poorly defined objective thresholds. To address this limitation, we evaluated a qualitative MRI score for predicting neurological outcome in CA survivors., Methods: Adult comatose CA survivors who underwent MRI were retrospectively identified at a single academic medical center. Two blinded neurointensivists qualitatively scored HIBI amongst 12 MRI brain regions. Scores were summated to form four distinct score groups: cortex, deep grey nuclei (DGN), cortex-DGN combined, and total (cortex, DGN, brainstem, and cerebellum). Poor neurological outcome was defined as Cerebral Performance Category (CPC) score 3-5 at hospital discharge. Inter-rater reliability was tested using intra-class correlation (ICC) and discrimination of poor neurological outcome assessed using area under the receiver operating curve (AUC)., Results: Our cohort included 219 patients with median time to MRI of 96 (IQR 81-110) hours. ICC (95% CI) was good to excellent across all MRI scores: cortex 0.92 (0.89-0.94), DGN 0.88 (0.80-0.92), cortex-DGN 0.94 (0.92-0.95), and total 0.93 (0.91-0.95). AUC (95% CI) for poor outcome was good across all MRI scores: cortex 0.84 (0.78-0.90), DGN 0.83 (0.77-0.89), cortex-DGN 0.83 (0.77-0.89), and total 0.83 (0.77-0.88)., Conclusion: A simplified, qualitative MRI score had excellent reliability and good discrimination for poor neurologic outcome. Further work is necessary to externally validate our findings in an independent, ideally prospective, cohort., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: “Dr. Tripodis receives research support from the NIH and the AMA. Dr. Greer receives research funding in the form of a grant to Boston Medical Center to conduct the INTREPID study as co-PI, including reimbursed travel to present results at major conferences. In unrelated support, Dr. Greer receives research support from NIH/NINDS, as well as personal compensation as Editor-in-Chief for Seminars in Neurology, royalties for several books, as well as medical-legal expert work.”., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: Hypoxic-ischemic brain injury is the main cause of death and disability of comatose patients after cardiac arrest. Early and reliable prognostication is challenging. Common prognostic tools include clinical neurological examination and electrophysiological measures. Brain imaging is well established for diagnosis of focal cerebral ischemia but has so far not found worldwide application in this patient group., Objective: To review the value of Computed Tomography (CT), Magnetic Resonance Imaging (MRI), and Positron Emission Tomography (PET) for early prediction of neurological outcome of comatose survivors of cardiac arrest., Methods: A literature search was performed to identify publications on CT, MRI or PET in comatose patients after cardiac arrest., Results: We included evidence from 51 articles, 21 on CT, 27 on MRI, 1 on CT and MRI, and 2 on PET imaging. Studies varied regarding timing of measurements, choice of determinants, and cut-off values predicting poor outcome. Most studies were small (n = 6-398) and retrospective (60%). In general, cytotoxic oedema, defined by a grey-white matter ratio <1.10, derived from CT, or MRI-diffusion weighted imaging <650 × 10 -6  mm 2 /s in >10% of the brain could differentiate between patients with favourable and unfavourable outcomes on a group level within 1-3 days after cardiac arrest. Advanced imaging techniques such as functional MRI or diffusion tensor imaging show promising results, but need further evaluation., Conclusion: CT derived grey-white matter ratio and MRI based measures of diffusivity and connectivity hold promise to improve outcome prediction after cardiac arrest. Prospective validation studies in a multivariable approach are needed to determine the additional value for the individual patient., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Introduction: Predicting neurologic outcomes after cardiac arrest (CA) is challenging. This study tested the hypothesis that a quantitative analysis of diffusion weighted imaging (DWI) using the FMRIB Software Library (FSL) can predict neurologic outcomes after CA and can clarify the optimal apparent diffusion coefficient (ADC) thresholds for predicting poor neurologic outcomes., Methods: Out-of-hospital CA patients treated with targeted temperature management (TTM) who underwent DWI were included in this study. Voxel-based analysis was performed to calculate the mean ADC value. ADC thresholds (750, 700, 650, 600, 550, 500, 450 and 400) and brain volumes below each threshold were also analyzed for their correlation with outcomes. The patients were divided into early (within 48 h after return of spontaneous circulation (ROSC)) and late group (between 48 h and 7 days after ROSC) according to the DWI scan time. The primary outcome was a poor neurologic outcome at 6 months after CA, defined as a cerebral performance category (CPC) of 3-5., Results: One hundred ten DWIs were analyzed. The mean ADC values were 789.0 (761.5-826.5) × 10 -6  mm 2 /s for the good neurologic outcome group and 715.2 (663.1-778.4) × 10 -6  mm 2 /s for the poor neurologic outcome group (p < 0.001). All the ADC thresholds could differentiate patients with good versus poor outcomes. The ADC threshold of 400 × 10 -6  mm 2 /s had the highest odds ratio (4.648 in the early group and 11.283 in the late group) after adjusting for initial rhythm and anoxic time. To achieve 100% specificity using an ADC threshold of 400 × 10 -6  mm 2 /s, the sensitivity was 64% (cutoff value; >2.5% ADC threshold of 400 × 10 -6  mm 2 /s) in the early group and 79.2% (cutoff value; >1.66% ADC threshold of 400 × 10 -6  mm 2 /s) in the late group., Conclusions: Voxel-based analysis using FSL software can predict neurologic outcomes after CA. The ADC threshold of 400 × 10 -6  mm 2 /s had the highest OR for predicting a poor neurologic outcome., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Traditional predictors of neurological prognosis after cardiac arrest are unreliable after targeted temperature management. Absence of pupillary reflexes remains a reliable predictor of poor outcome. Diffusion-weighted imaging has emerged as a potential predictor of recovery, and here we compare imaging characteristics to pupillary exam., Methods: We identified 69 patients who had MRIs within seven days of arrest and used a semi-automated algorithm to perform quantitative volumetric analysis of apparent diffusion coefficient (ADC) sequences at various thresholds. Area under receiver operating characteristic curves (ROC-AUC) were estimated to compare predictive values of quantitative MRI with pupillary exam at days 3, 5 and 7 post-arrest, for persistence of coma and functional outcomes at discharge. Cerebral Performance Category scores of 3-4 were considered poor outcome., Results: Excluding patients where life support was withdrawn, ≥2.8% diffusion restriction of the entire brain at an ADC of ≤650×10 -6 m 2 /s was 100% specific and 68% sensitive for failure to wake up from coma before discharge. The ROC-AUC of ADC changes at ≤450×10 -6 mm 2 /s and ≤650×10 -6 mm 2 /s were significantly superior in predicting failure to wake up from coma compared to bilateral absence of pupillary reflexes. Among survivors, >0.01% of diffusion restriction of the entire brain at an ADC ≤450×10 -6 m 2 /s was 100% specific and 46% sensitive for poor functional outcome at discharge. The ROC curve predicting poor functional outcome at ADC ≤450×10 -6 mm 2 /s had an AUC of 0.737 (0.574-0.899, p=0.04)., Conclusion: Post-anoxic diffusion changes using quantitative brain MRI may aid in predicting persistent coma and poor functional outcomes at hospital discharge., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Aim of the Study: Previous studies found that the gray matter to white matter ratio (GWR) on brain computed tomography (CT) could be used to predict poor outcomes in cardiac arrest survivors. However, these studies have included cardiac arrests of both cardiac and non-cardiac etiologies. We sought to evaluate if the GWR on brain CT can help to predict poor outcomes after out-of-hospital cardiac arrest (OHCA) of cardiac etiology., Methods: Using a multicenter retrospective registry of adult cardiac arrest survivors treated with therapeutic hypothermia, we identified survivors of OHCA of cardiac etiology who underwent brain CT within 24h after successful resuscitation. Gray and white matter attenuations were measured, and the GWRs were calculated as in previous studies. The prognostic values of the GWRs were analyzed, and a logistic regression analysis was performed to determine the contribution of the GWR in predicting poor outcomes (Cerebral Performance Category 3-5)., Results: of 283 included patients, 140 had good outcomes and 143 had poor outcomes. Although the GWRs could predict poor outcomes with statistical significance, the sensitivities were remarkably low (3.5% to 5.6%) at cutoff values with 100% specificity. No significant difference in predictive performance was found between the primary predictive model, containing independent poor outcome predictors, and the primary predictive model combined with the GWR., Conclusion: In a cohort of comatose adults after OHCA of cardiac etiology, the GWR demonstrated poor predictive performance and was not helpful in predicting poor outcomes., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Aim of the Study: We determined whether combining the grey-to-white matter ratio (GWR) on brain computed tomography (CT) and serum neuron specific enolase (NSE) improves the prognostic performance when compared to either alone in cardiac arrest patients treated with therapeutic hypothermia (TH)., Methods: We performed a retrospective study of a cohort of cardiac arrest patients treated with TH. The Hounsfield unit was measured in the caudate nucleus (CN), putamen (P), posterior limb of internal capsule (PIC) and corpus callosum (CC); GWR was calculated as CN/PIC and P/CC. The NSE value was obtained at 0, 24, and 48h after restoration of spontaneous circulation (ROSC). We analysed the prognostic performance of GWR and NSE, singly and in combination, in predicting poor neurologic outcome (cerebral performance category 3-5)., Results: Of the 224 included patients, 82 showed good neurologic outcome at hospital discharge, while 142 showed poor neurologic outcome. The P/CC (area under receiver operating characteristics (AUROC) 0.864, sensitivity/specificity 52.9%/100%) showed better prognostic performance than did the CN/PIC (AUROC 0.721, sensitivity/specificity 19.8%/100%). The NSE value at 48h after ROSC (AUROC 0.895, sensitivity/specificity 60.2%/100%) showed the highest prognostic value among the three NSE time points. Analysis of 119 patients undergoing both brain CT and NSE at 48h indicated that combining P/CC and NSE improved the sensitivity (78.6%) compared to either alone (48.6%, 62.9%)., Conclusion: Combining brain CT and serum NSE improves the prognostic performance when compared to either alone in predicting poor neurologic outcome in cardiac arrest patients treated with TH., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Background: Prolonged coma is not an uncommon clinical problem following resuscitation from cardiac arrest. Early and precise prediction of outcome is highly desirable for ethical and economical reasons. The aims of this study were to use positron emission tomography (PET) to investigate the regional dynamic changes of cerebral blood flow and metabolism during the early period after cardiopulmonary resuscitation (CPR) in unconscious patients and to evaluate if PET may be a potential prognostic evaluator., Methods and Results: PET and Glasgow Coma Scale examinations were sequentially performed on days 1, 3 and 7 in seven patients remaining comatose post CPR. Each PET included regional determinations of cerebral blood flow (rCBF), oxygen metabolism (rCMRO(2)), oxygen extraction ratio (rOER), and cerebral blood volume (rCBV). One patient was excluded due to complex trauma problems. Three patients remained unconscious until death and three woke up. All patients initially exhibited low CMRO(2) and CBF. Increased OER was only found exceptionally and when present was predominantly in focal areas. The comatose patients showed progressive depression of CMRO(2) and after 1 week had lower CMRO(2) than those patients who woke up. This difference was most pronounced in the putamen and occipital cortex. Two of the seven patients developed large focal infarcts., Conclusions: An initially low CMRO(2) was common to all patients. Early development of subclinical focal ischemic lesions was also common. The progressive depression of CMRO(2) over the first week in those patients remaining unconscious may be an indication of prolonged but not necessarily permanent coma. Further studies are required to identify pathophysiological features that can predict the long-term clinical outcome in patients who remain unconscious after 1 week.

Interest was aroused in two patients of 16 and 17 years of age and similar craniocerebral trauma, but who had differing EEG's 1 year after injury while their later situation was the reverse of what the EEG would have led one to expect. The patient with an iso-electric EEG showed clinical improvement during the course of the second year, as indicated by a rise in his Glasgow coma rating from 8 to 11. This patient had marked cortical atrophy with discrete central atrophy, shown by computed axial tomography (CT); the isotope cisternogram showed good peripheral absorption of the isotope and no penetration into the ventricles. The other patient showed diffuse slow-wave activity in his EEG but failed to improve clinically or electroencephalographically. His CT-scan showed marked central and discrete cortical atrophy; his isotopic cisternogram showed penetration of isotope into the ventricles with poor peripheral absorption. These two cases illustrate the hazard of relying on an iso-electric EEG after 1 year of coma as an indicator of brain death, and the value of the CT-scan in the initial assessment of such cases.