The density ratio of grey to white matter on computed tomography as an early predictor of vegetative state or death after cardiac arrest

Grey-to-White Matter Ratio Values in Early Head Computed Tomography (CT) as a Predictor of Neurologic Outcomes in Survivors of Out-of-Hospital Cardiac Arrest Based on Severity of Hypoxic-Ischemic Brain Injury

BACKGROUND

Hypoxic-ischemic brain injury (HIBI) is a common complication of out-of-hospital cardiac arrest (OHCA).

OBJECTIVES

We investigated whether grey-to-white matter ratio (GWR) values, measured using early head computed tomography (HCT), were associated with neurologic outcomes based on the severity of HIBI in survivors of OHCA.

METHODS

This retrospective multicenter study included adult comatose OHCA survivors who underwent an HCT scan within 2 h after the return of spontaneous circulation. HIBI severity was assessed using the revised post-Cardiac Arrest Syndrome for Therapeutic hypothermia (rCAST) scale (low, moderate, and severe). Poor neurologic outcomes were defined as Cerebral Performance Categories 3 to 5 at 6 months after OHCA.

RESULTS

Among 354 patients, 27% were women and 224 (63.3%) had poor neurologic outcomes. The distribution of severity was 19.5% low, 47.5% moderate, and 33.1% severe. The area under the receiver operating curves of the GWR values for predicting rCAST severity (low, moderate, and severe) were 0.52, 0.62, and 0.79, respectively. The severe group had significantly higher predictive performance than the moderate group (p = 0.02). Multivariate logistic regression analysis revealed a significant association between GWR values and poor neurologic outcomes in the moderate group (adjusted odds ratio = 0.012, 95% CI 0.0-0.54, p = 0.02).

CONCLUSIONS

In this cohort study, GWR values measured using early HCT demonstrated variations in predicting neurologic outcomes based on HIBI severity. Furthermore, GWR in the moderate group was associated with poor neurologic outcomes.

New perspectives on assessment and understanding of the patient with cranial bone defect: a morphometric and cerebral radiodensity assessment

Background

Skull defects after decompressive craniectomy (DC) cause physiological changes in brain function and patients can have neurologic symptoms after the surgery. The objective of this study is to evaluate whether there are morphometric changes in the cortical surface and radiodensity of brain tissue in patients undergoing cranioplasty and whether those variables are correlated with neurological prognosis.

Methods

This is a prospective cohort with 30 patients who were submitted to cranioplasty and followed for 6 months. Patients underwent simple head CT before and after cranioplasty for morphometric and cerebral radiodensity assessment. A complete neurological exam with Mini-Mental State Examination (MMSE), modified Rankin Scale, and the Barthel Index was performed to assess neurological prognosis.

Results

There was an improvement in all symptoms of the syndrome of the trephined, specifically for headache (p = 0.004) and intolerance changing head position (p = 0.016). Muscle strength contralateral to bone defect side also improved (p = 0.02). Midline shift of intracranial structures decreased after surgery (p = 0.004). The Anterior Distance Difference (ADif) and Posterior Distance Difference (PDif) were used to assess morphometric changes and varied significantly after surgery. PDif was weakly correlated with MMSE (p = 0.03; r = -0.4) and Barthel index (p = 0.035; r = -0.39). The ratio between the radiodensities of gray matter and white matter (GWR) was used to assess cerebral radiodensity and was also correlated with MMSE (p = 0.041; r = -0.37).

Conclusion

Morphological anatomy and radiodensity of the cerebral cortex can be used as a tool to assess neurological prognosis after DC.

Recovery and Survival of Patients After Out-of-Hospital Cardiac Arrest: A Literature Review Showcasing the Big Picture of Intensive Care Unit-Related Factors

As an important public health issue, out-of-hospital cardiac arrest (OHCA) requires several stages of high quality medical care, both on-field and after hospital admission. Post-cardiac arrest shock can lead to severe neurological injury, resulting in poor recovery outcome and increased risk of death. These characteristics make this condition one of the most important issues to deal with in post-OHCA patients hospitalized in intensive care units (ICUs). Also, the majority of initial post-resuscitation survivors have underlying coronary diseases making revascularization procedure another crucial step in early management of these patients. Besides keeping myocardial blood flow at a satisfactory level, other tissues must not be neglected as well, and maintaining mean arterial pressure within optimal range is also preferable. All these procedures can be simplified to a certain level along with using targeted temperature management methods in order to decrease metabolic demands in ICU-hospitalized post-OHCA patients. Additionally, withdrawal of life-sustaining therapy as a controversial ethical topic is under constant re-evaluation due to its possible influence on overall mortality rates in patients initially surviving OHCA. Focusing on all of these important points in process of managing ICU patients is an imperative towards better survival and complete recovery rates.

Neuromonitoring after Pediatric Cardiac Arrest: Cerebral Physiology and Injury Stratification

BACKGROUND

Significant long-term neurologic disability occurs in survivors of pediatric cardiac arrest, primarily due to hypoxic-ischemic brain injury. Postresuscitation care focuses on preventing secondary injury and the pathophysiologic cascade that leads to neuronal cell death. These injury processes include reperfusion injury, perturbations in cerebral blood flow, disturbed oxygen metabolism, impaired autoregulation, cerebral edema, and hyperthermia. Postresuscitation care also focuses on early injury stratification to allow clinicians to identify patients who could benefit from neuroprotective interventions in clinical trials and enable targeted therapeutics.

METHODS

In this review, we provide an overview of postcardiac arrest pathophysiology, explore the role of neuromonitoring in understanding postcardiac arrest cerebral physiology, and summarize the evidence supporting the use of neuromonitoring devices to guide pediatric postcardiac arrest care. We provide an in-depth review of the neuromonitoring modalities that measure cerebral perfusion, oxygenation, and function, as well as neuroimaging, serum biomarkers, and the implications of targeted temperature management.

RESULTS

For each modality, we provide an in-depth review of its impact on treatment, its ability to stratify hypoxic-ischemic brain injury severity, and its role in neuroprognostication.

CONCLUSION

Potential therapeutic targets and future directions are discussed, with the hope that multimodality monitoring can shift postarrest care from a one-size-fits-all model to an individualized model that uses cerebrovascular physiology to reduce secondary brain injury, increase accuracy of neuroprognostication, and improve outcomes.

Emergent surgical evacuation of traumatic intracranial hematoma in patients with preoperative thrombocytopenia: surgical risk and early outcome

BACKGROUND

Surgical evacuation of intracranial hematoma, including epidural, subdural, intracerebral, and intraventricular hematoma, is recommended in patients with traumatic brain injury (TBI) for prevention of cerebral herniation and possible saving of life. However, preoperative coagulopathy is a major concern for emergent surgery on patients with severe TBI.

METHODS

We reviewed 65 consecutive patients with severe TBI who underwent emergency craniotomy for intracranial hematomas.

RESULTS

Univariate analysis showed preoperative pupil abnormality, absence of pupil light reflex, respiratory failure, preoperative thrombocytopenia (< 100 × 10⁹/L), increased activated partial thromboplastin time (> 36 s), low fibrinogen (< 150 mg/dL), platelet transfusion, red cell concentrate transfusion, and presence of brain contusion and traumatic subarachnoid hemorrhage (SAH) on computed tomography were correlated with poor outcome (death or vegetative state). Multivariate analysis revealed that pupil abnormality (p = 0.001; odds ratio [OR] 0.064, 95% confidence interval [CI] 0.012-0.344), preoperative thrombocytopenia (p = 0.016; OR 0.101, 95% CI 0.016-0.656), and traumatic SAH (p = 0.021; OR 0.211, 95% CI 0.057-0.791) were significant factors. Investigation of the 14 patients with preoperative thrombocytopenia found the emergency surgery was successful, with no postoperative bleeding during hospitalization. However, half of the patients died, and almost a quarter remained in the vegetative state mainly associated with severe cerebral edema.

CONCLUSIONS

Emergent craniotomy for patients with severe TBI who have preoperative thrombocytopenia is often successful, but the prognosis is often poor. Emergency medical care teams and neurosurgeons should be aware of this discrepancy between successful surgery and poor prognosis in these patients. Further study may be needed on the cerebral edema regulator function of platelets.

Evaluation of the prognosis of acute subdural hematoma according to the density differences between gray and white matter

Objective

Acute subdural hematoma (ASDH) is a common neurological emergency, and its appearance on head-computed tomographic (CT) imaging helps guide clinical treatment. To provide a basis for clinical decision-making, we analyzed that the density difference between the gray and white matter of the CT image is associated with the prognosis of patients with ASDH.

Methods

We analyzed the data of 194 patients who had ASDH as a result of closed traumatic brain injury (TBI) between 2018 and 2021. The patients were subdivided into surgical and non-surgical groups, and the non-surgical group was further subdivided into "diffused [hematoma]" and "non-diffused" groups. The control group's CT scans were normal. The 3D Slicer software was used to quantitatively analyze the density of gray and white matter depicted in the CT images.

Results

Imaging evaluation showed that the median difference in density between the gray and white matter on the injured side was 4.12 HU (IQR, 3.91-4.22 HU; p < 0.001) and on the non-injured side was 4.07 HU (IQR, 3.90-4.19 HU; p < 0.001), and the hematoma needs to be surgically removed. The median density difference value of the gray and white matter on the injured side was 3.74 HU (IQR, 3.53-4.01 HU; p < 0.001) and on the non-injured side was 3.71 HU (IQR, 3.69-3.73 HU; p < 0.001), and the hematoma could diffuse in a short time.

Conclusion

Quantitative analysis of the density differences in the gray and white matter of the CT images can be used to evaluate the clinical prognosis of patients with ASDH.

Gray-White Matter Ratio at the Level of the Basal Ganglia as a Predictor of Neurologic Outcomes in Cardiac Arrest Survivors: A Literature Review

Loss of gray-white matter discrimination is the primary early imaging finding within of cranial computed tomography in cardiac arrest survivors, and this has been also regarded as a novel predictor for evaluating neurologic outcome. As displayed clearly on computed tomography and based on sensitivity to hypoxia, the gray-white matter ratio at basal ganglia (GWR-BG) region was frequently detected to assess the neurologic outcome by several studies. The specificity of GWR-BG is 72.4 to 100%, while the sensitivity is significantly different. Herein we review the mechanisms mediating cerebral edema following cardiac arrest, demonstrate the determination procedures with respect to GWR-BG, summarize the related researches regarding GWR-BG in predicting neurologic outcomes within cardiac arrest survivors, and discuss factors associated with predicting the accuracy of this methodology. Finally, we describe the effective measurements to increase the sensitivity of GWR-BG in predicting neurologic outcome.

Clinical Significance of Gray to White Matter Ratio after Cardiopulmonary Resuscitation in Children

Cardiopulmonary resuscitation (CPR) successfully restores systemic circulation approximately 50% of the time; however, many successfully restored patients have severe neurologic damage. In adults, the gray matter to white matter attenuation ratio (GWR) in brain computed tomography (CT) correlates with the neurologic outcome. However, in children, the clinical significance of GWR still remains unclear. The aim of this study was to evaluate the clinical characteristics of children who underwent CPR for cardiac arrest according to the survival and to demonstrate the differentiation of grey/white matter by Hounsfield units of brain CT and to characterize the attenuations of grey and white matters. Methods: This is a retrospective single-center study. We enrolled those who underwent brain CT within 24 h after return of spontaneous circulation (ROSC) from January 2005 to June 2018. Brain CTs were taken within 24 h of ROSC. We measured the attenuation of grey and white matter in Hounsfield units and calculated GWR. They were compared with healthy controls. Patients were analyzed as follows: survivors vs. non-survivors and better neurologic outcome vs. worse neurologic outcome. Results: Among 100 pediatric patients who had CPR, 56 met inclusion criteria. There were 24 patients who survived and 32 non-survivors. Our study revealed that the incidence of seizure, duration of CPR, and instances of hypothermia were significantly different between survivors and non-survivors. In both survivors and non-survivors, the attenuation of the caudate nucleus, putamen, GWR-basal ganglia, and average GWR were significantly different from controls. In regression analyses, the medial cortex and average GWR were the significant variables to predict survival, and the receiver operating curves revealed areas under curve of 0.733 and 0.666, respectively. Also, the medial cortex 1 was the only variable that predicted the neurologic outcome. Conclusions: There was some predictive survival value of GWR and medial cortex at the centrum semiovale level in early brain CT within 24 h after cardiac arrest. Although we could not find the predictive value of GWR in the neurologic outcome of pediatric patients, we found that the absolute attenuation of the medial cortex was low in patients with worse neurologic outcomes. Further prospective, multicenter studies are needed to determine the predictive value of GWR and the medial cortex.

Machine Learning for Early Detection of Hypoxic-Ischemic Brain Injury After Cardiac Arrest

Background

Establishing whether a patient who survived a cardiac arrest has suffered hypoxic-ischemic brain injury (HIBI) shortly after return of spontaneous circulation (ROSC) can be of paramount importance for informing families and identifying patients who may benefit the most from neuroprotective therapies. We hypothesize that using deep transfer learning on normal-appearing findings on head computed tomography (HCT) scans performed after ROSC would allow us to identify early evidence of HIBI.

Methods

We analyzed 54 adult comatose survivors of cardiac arrest for whom both an initial HCT scan, done early after ROSC, and a follow-up HCT scan were available. The initial HCT scan of each included patient was read as normal by a board-certified neuroradiologist. Deep transfer learning was used to evaluate the initial HCT scan and predict progression of HIBI on the follow-up HCT scan. A naive set of 16 additional patients were used for external validation of the model.

Results

The median age (interquartile range) of our cohort was 61 (16) years, and 25 (46%) patients were female. Although findings of all initial HCT scans appeared normal, follow-up HCT scans showed signs of HIBI in 29 (54%) patients (computed tomography progression). Evaluating the first HCT scan with deep transfer learning accurately predicted progression to HIBI. The deep learning score was the most significant predictor of progression (area under the receiver operating characteristic curve = 0.96 [95% confidence interval 0.91–1.00]), with a deep learning score of 0.494 having a sensitivity of 1.00, specificity of 0.88, accuracy of 0.94, and positive predictive value of 0.91. An additional assessment of an independent test set confirmed high performance (area under the receiver operating characteristic curve = 0.90 [95% confidence interval 0.74–1.00]).

Conclusions

Deep transfer learning used to evaluate normal-appearing findings on HCT scans obtained early after ROSC in comatose survivors of cardiac arrest accurately identifies patients who progress to show radiographic evidence of HIBI on follow-up HCT scans.

Differential Effectiveness of Hypothermic Targeted Temperature Management According to the Severity of Post-Cardiac Arrest Syndrome

International guidelines recommend targeted temperature management (TTM) to improve the neurological outcomes in adult patients with post-cardiac arrest syndrome (PCAS). However, it still remains unclear if the lower temperature setting (hypothermic TTM) or higher temperature setting (normothermic TTM) is superior for TTM. According to the most recent large randomized controlled trial (RCT), hypothermic TTM was not found to be associated with superior neurological outcomes than normothermic TTM in PCAS patients. Even though this represents high-quality evidence obtained from a well-designed large RCT, we believe that we still need to continue investigating the potential benefits of hypothermic TTM. In fact, several studies have indicated that the beneficial effect of hypothermic TTM differs according to the severity of PCAS, suggesting that there may be a subgroup of PCAS patients that is especially likely to benefit from hypothermic TTM. Herein, we summarize the results of major RCTs conducted to evaluate the beneficial effects of hypothermic TTM, review the recent literature suggesting the possibility that the therapeutic effect of hypothermic TTM differs according to the severity of PCAS, and discuss the potential of individualized TTM.

Differences in the gray-to-white matter ratio according to different computed tomography scanners for outcome prediction in post-cardiac arrest patients receiving target temperature management

The gray-to-white matter ratio (GWR) has been used to identify brain damage in comatose patients after cardiac arrest. However, Hounsfield units (HUs), the measurement of brain density on computed tomography (CT) images, may vary depending on the machine type or parameter. Therefore, differences in CT scanners may affect the GWR in post-cardiac arrest patients. We performed a retrospective study on comatose post-cardiac arrest patients who visited the hospital from 2007 to 2017. Two CT, Lightspeed and SOMATOM, scanners were used. Two observers independently measured the HUs of the caudate nucleus, putamen, posterior internal capsule, and corpus callosum using regions of interest. We compared the GWR calculated from the HUs measured at different CT scanners. The analysis of different scanners showed statistically significant differences in the measured HUs and GWR. The HUs and GWR of Lightspeed were measured lower than SOMATOM. The difference between the two CT scanners was also evident in groups divided by neurological prognosis. The area under the curve of the receiver operating characteristic curve to predict poor outcomes of Lightspeed was 0.798, and the cut-off value for 100% specificity was 1.172. The SOMATOM was 0.855, and the cut-off value was 1.269. The difference in scanners affects measurements and performance characteristics of the GWR in post-cardiac arrest patients. Therefore, when applying the results of the GWR study to clinical practice, reference values for each device should be presented, and an integrated plan should be prepared.

Head CT: Toward Making Full Use of the Information the X-Rays Give

Although clinical head CT images are typically interpreted qualitatively, automated methods applied to routine clinical head CTs enable quantitative assessment of brain volume, brain parenchymal fraction, brain radiodensity, and brain radiomass. These metrics gain clinical meaning when viewed relative to a reference database and expressed as quantile regression values. Quantitative imaging data can aid in objective reporting and in the identification of outliers, with possible diagnostic implications. The comparison to a reference database necessitates standardization of head CT imaging parameters and protocols. Future research is needed to learn the effects of virtual monochromatic imaging on the quantitative characteristics of head CT images.

Densitometric analysis of brain computed tomography as a new prognostic factor in patients with acute subdural hematoma

OBJECTIVE

Acute subdural hematoma (ASDH) is a major cause of mortality and morbidity after traumatic brain injury (TBI). Surgical evacuation is the mainstay of treatment in patients with altered neurological status or significant mass effect. Nevertheless, concerns regarding surgical indication still persist. Given that clinicians often make therapeutic decisions on the basis of their prognosis assessment, to accurately evaluate the prognosis is of great significance. Unfortunately, there is a lack of specific and reliable prognostic models. In addition, the interdependence of certain well-known predictive variables usually employed to guide surgical decision-making in ASDH has been proven. Because gray matter and white matter are highly susceptible to secondary insults during the early phase after TBI, the authors aimed to assess the extent of these secondary insults with a brain parenchyma densitometric quantitative CT analysis and to evaluate its prognostic capacity.

METHODS

The authors performed a retrospective analysis among their prospectively collected cohort of patients with moderate to severe TBI. Patients with surgically evacuated, isolated, unilateral ASDH admitted between 2010 and 2017 were selected. Thirty-nine patients were included. For each patient, brain parenchyma density in Hounsfield units (HUs) was measured in 10 selected slices from the supratentorial region. In each slice, different regions of interest (ROIs), including and excluding the cortical parenchyma, were defined. The injured hemisphere, the contralateral hemisphere, and the absolute differences between them were analyzed. The outcome was evaluated using the Glasgow Outcome Scale–Extended at 1 year after TBI.

RESULTS

Fifteen patients (38.5%) had a favorable outcome. Collected demographic, clinical, and radiographic data did not show significant differences between favorable and unfavorable outcomes. In contrast, the densitometric analysis demonstrated that greater absolute differences between both hemispheres were associated with poor outcome. These differences were detected along the supratentorial region, but were greater at the high convexity level. Moreover, these HU differences were far more marked at the cortical parenchyma. It was also detected that these differences were more prone to ischemic and/or edematous insults than to hyperemic changes. Age was significantly correlated with the side-to-side HU differences in patients with unfavorable outcome.

CONCLUSIONS

The densitometric analysis is a promising prognostic tool in patients diagnosed with ASDH. The supplementary prognostic information provided by the densitometric analysis should be evaluated in future studies.

Predictive Value of Gray-Matter-White-Matter Ratio on Brain Computed Tomography for Delayed Encephalopathy after Acute Carbon Monoxide Poisoning: A Retrospective Cohort Study

Background

This study is aimed at determining the predictive value of the gray-matter–white-matter ratio (GWR) on brain computed tomography for delayed encephalopathy after acute carbon monoxide (CO) poisoning (DEACMP).

Methods

This retrospective cohort study reviewed 352 patients with acute CO poisoning and who underwent the brain computed tomography test. These patients were admitted to Cangzhou Central Hospital from May 2010 to May 2020. The patients were divided into the DEACMP (n = 16) and non-DEACMP (n = 336) groups. Pearson's correlation coefficients were computed for correlation analysis. The predictive value of GWR for DEACMP was evaluated by using logistic regression analysis and receiver operator characteristic curves.

Results

The morbidity of DEACMP was 4.5% (16/352). The GWR-basal ganglia, GWR-cerebrum, and GWR-average in the DEACMP group were lower than those in the non-DEACMP group. Correlation analysis indicated that GWR-basal ganglia (r = 0.276; P < 0.001), GWR-cerebrum (r = 0.163; P = 0.002), and GWR-average (r = 0.200; P < 0.001) were correlated with DEACMP. Multivariate logistic regression analysis revealed that reduced GWR-basal ganglia, GWR-cerebrum, and GWR-average were independent risk factors (P < 0.001; P = 0.008; P = 0.001; respectively). Compared with GWR-cerebrum and GWR-average, GWR-basal ganglia had a higher area under the curve of 0.881 (95% confidence interval: 0.783–0.983) with sensitivity and specificity of 93.8% and 68.7%, respectively. The cut-off value of GWR-basal ganglia was 1.055.

Conclusion

GWR, especially GWR-basal ganglia, is an early useful predictor for DEACMP.

Comparison of Prognostic Performance between Neuron-Specific Enolase and S100 Calcium-Binding Protein B Obtained from the Cerebrospinal Fluid of Out-of-Hospital Cardiac Arrest Survivors Who Underwent Targeted Temperature Management

We compared the prognostic performances of serum neuron-specific enolase (sNSE), cerebrospinal fluid (CSF) NSE (cNSE), and CSF S100 calcium-binding protein B (cS100B) in out-of-hospital cardiac arrest (OHCA) survivors. This prospective observational study enrolled 45 patients. All samples were obtained immediately and at 24 h intervals until 72 h after the return of spontaneous circulation. The inter- and intragroup differences in biomarker levels, categorized by 3 month neurological outcome, were analyzed. The prognostic performances were evaluated with receiver operating characteristic curves. Twenty-two patients (48.9%) showed poor outcome. At all-time points, sNSE, cNSE, and cS100B were significantly higher in the poor outcome group than in the good outcome group. cNSE and cS100B significantly increased over time (baseline vs. 24, 48, and 72 h) in the poor outcome group than in the good outcome group. sNSE at 24, 48, and 72 h showed significantly lower sensitivity than cNSE or cS100B. The sensitivities associated with 0 false-positive rate (FPR) for cNSE and cS100B were 66.6% vs. 45.5% at baseline, 80.0% vs. 80.0% at 24 h, 84.2% vs. 94.7% at 48 h, and 88.2% (FPR, 5.0%) vs. 94.1% at 72 h. High cNSE and cS100B are strong predictors of poor neurological outcome in OHCA survivors. Multicenter prospective studies may determine the generalizability of these results.

Multimodal Long-Term Predictors of Outcome in Out of Hospital Cardiac Arrest Patients Treated with Targeted Temperature Management at 36 °C

Introduction: Early prediction of long-term outcomes in patients resuscitated after cardiac arrest (CA) is still challenging. Guidelines suggested a multimodal approach combining multiple predictors. We evaluated whether the combination of the electroencephalography (EEG) reactivity, somatosensory evoked potentials (SSEPs) cortical complex and Gray to White matter ratio (GWR) on brain computed tomography (CT) at different temperatures could predict survival and good outcome at hospital discharge and six months after the event. Methods: We performed a retrospective cohort study including consecutive adult, non-traumatic patients resuscitated from out-of-hospital CA who remained comatose on admission to our intensive care unit from 2013 to 2017. We acquired SSEPs and EEGs during the treatment at 36 °C and after rewarming at 37 °C, Gray to white matter ratio (GWR) was calculated on the brain computed tomography scan performed within six hours of the hospital admission. We primarily hypothesized that SSEP was associated with favor-able functional outcome at distance and secondarily that SSEP provides independent information from EEG and CT. Outcomes were evaluated using the Cerebral Performance Category (CPC) scale at six months from discharge. Results: Of 171 resuscitated patients, 75 were excluded due to missing data or uninterpretable neurophysiological findings. EEG reactivity at 37 °C has been shown the best single predictor of good out-come (AUC 0.803) while N20P25 was the best single predictor for survival at each time point. (AUC 0.775 at discharge and AUC 0.747 at six months follow up). The predictive value of a model including EEG reactivity, average GWR, and SSEP N20P25 amplitude was superior (AUC 0.841 for survival and 0.920 for good out-come) to any combination of two tests or any single test. Conclusions: Our study, in which life-sustaining treatments were never suspended, suggests SSEP cortical complex N20P25, after normothermia and off sedation, is a reliable predictor for survival at any time. When SSEP cortical complex N20P25 is added into a model with GWR average and EEG reactivity, the predictivity for good outcome and survival at distance is superior than each single test alone.

Prognostic Values of the Gray-to-White Matter Ratio on Brain Computed Tomography Images for Neurological Outcomes after Cardiac Arrest: A Meta-Analysis

Materials and Methods

The PubMed, ScienceDirect, Web of Science, and China National Knowledge Infrastructure databases were searched for all relevant articles published before March 31, 2020, without any language restrictions. The pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated with a random-effects model using Stata 14.0 software.

Result

A total of 24 eligible studies with 2812 CA patients were recruited in the meta-analysis. The pooled result showed that decreased GWR was correlated with poor neurological outcomes after CA (OR = 11.28, 95% CI: 6.29–20.21, and P < 0.001) with moderate heterogeneity (I² = 71.5%, P < 0.001). The pooled sensitivity and specificity were 0.58 (95% CI: 0.47–0.68) and 0.95 (95% CI: 0.87–0.98), respectively. The area under the curve (AUC) of GWR was 0.84 (95% CI: 0.80–0.87). Compared with GWR (cerebrum) and GWR (average), GWR using the basal ganglion level of brain CT had the highest AUC of 0.87 (0.84–0.90). Subgroup analysis indicated that heterogeneity may be derived from the time of CT measurement, preset specificity, targeted temperature management, or proportion of cardiac etiology. Sensitivity analysis indicated that the result was stable, and Deeks' plot showed no possible publication bias (P = 0 .64).

Conclusion

Current research suggests that GWR, especially using the basal ganglion level of brain CT, is a useful parameter for determining neurological outcomes after CA.

Pediatric Head CT: Automated Quantitative Analysis with Quantile Regression

BACKGROUND AND PURPOSE

Together with quantile regression methods, such a model would have the potential for clinical utility through automated quantitative comparison of individual cases relative to their age and gender-matched peer group. Our aim was to demonstrate the automated processing of digital clinical head CT data in the development of a clinically useful model of age-related changes of the brain in the first 2 decades of life.

MATERIALS AND METHODS

A total of 415 (209 female) consecutive, clinical head CTs with radiographically normal findings from patients from birth through 20 years of age were retrospectively selected and subjected to automated segmentation. Brain volume, brain parenchymal fraction, brain radiodensity, and brain radiomass were assessed as a function of patient age. Statistical modeling and quantile regression were performed.

RESULTS

Brain volume increased from 400 cm3 at birth to 1350 cm3 at 20 years of age (>3-fold). Males had a slightly steeper growth trajectory than females, with approximately 8% difference in volume between the sexes established in the first few years of life. Brain parenchymal fraction was variable at younger than 2 years of age, stabilizing between 0.85 and 0.92 at 2-3 years of age. Brain mean radiodensity was lower at birth (24 HU) and increased through 3 years of age, after which it stabilized near 30 HU, an approximately 25% increase. The product of brain volume and mean brain radiodensity (radiomass), increased from 700 HU × mL at birth to 3900 HU × mL, a 5.6-fold increase, with approximately 5% difference between males and females at 20 years. Quantile regression enables a given metric to be interpreted relative to an age- and sex-matched peer group.

CONCLUSIONS

Automated segmentation of clinical head CT images permitted the generation of a reference database for quantitative analysis of pediatric and adolescent brains. Quantile regression facilitates clinical application.

Utility of brain parenchyma density measurement and computed tomography perfusion imaging in predicting brain death

Purpose

To assess the utility of brain parenchyma density measurement on unenhanced computed tomography (CT) in predicting brain death (BD), in order to evaluate the added value of CT perfusion (CTP).

Material and methods

A total of 77 patients who were clinically diagnosed as BD and had both CT angiography (CTA) and CTP imaging in the same session were retrospectively reviewed. On unenhanced phase of CTA, density measurement was performed from 23 regions of interests (ROIs) which were located in the following areas: level of basal ganglia (caudate nucleus, putamen, corpus callosum, posterior limb of internal capsule), level of brainstem, grey- white matters on levels of centrum semiovale (CS), high convexity (HC), and cerebellum. CTP images were evaluated qualitatively and independently. Grey matter (GM), white matter (WM), density, and GM/WM density ratio of BD patients were compared with control subjects.

Results

Comparing with the normal control group, the GM and WM density at each level and GM/WM density ratio of CS, HC, and cerebellum level were significantly lower in brain-dead patients (p = 0.019 for HC-WM, p < 0.001 for other areas). Using ROC analysis, the highest value of area under curve (AUC) for the GM/WM density ratio was found at the HC level (AUC = 0.907). The sensitivity of the GM/WM density ratio at the HC level was found to be 90% when the cut-off value of 1.25 was identified. Evaluating the GM/WM density ratio together with the CTP results increased the sensitivity further to 98%.

Conclusions

The GM/WM density ratio at the HC level on unenhanced CT may be a useful finding to predict BD. Also, the addition of CTP increases the sensitivity of this method.

Neurologic prognostication after resuscitation from cardiac arrest

Out-of-hospital cardiac arrest remains a leading cause of mortality in the United States, and the majority of patients who die after achieving return of spontaneous circulation die from withdrawal of care due to a perceived poor neurologic prognosis. Unfortunately, withdrawal of care often occurs during the first day of admission and research suggests this early withdrawal of care may be premature and result in unnecessary deaths for patients who would have made a full neurologic recovery. In this review, we explore the evidence for neurologic prognostication in the emergency department for patients who achieve return of spontaneous circulation after an out-of-hospital cardiac arrest.

Duration and clinical features of cardiac arrest predict early severe cerebral edema

BACKGROUND

Severe brain edema appears early after cardiopulmonary resuscitation (CPR) in a subset of patients and portends a poor prognosis. We tested whether clinical features of patients or resuscitation during out-of-hospital cardiac arrest (OHCA) are associated with early, severe cerebral edema.

METHOD/RESEARCH DESIGN

We reviewed pre-hospital and hospital records for comatose patients surviving to hospital admission after OHCA who had computed tomography (CT) of brain at the time of hospital admission available for inspection. We measured the gray-white ratio (GWR) of X-ray attenuation between the caudate nucleus and posterior limb of the internal capsule, defining severe cerebral edema as GWR < 1.20. We calculated associations between severe cerebral edema and patient or resuscitation variables.

RESULTS

Between 2010 and 2019, 1340 subjects were admitted of whom 296 (22%) showed severe cerebral edema on initial CT. Subjects with severe edema had lower survival (5/296, 2% vs. 377/1044, 36%). Severe edema was independently associated with total CPR duration, total dose of epinephrine, younger age, non-shockable arrest rhythms, fewer total number of rescue shocks, rearrest after initial return of pulses, and non-cardiac arrest etiology. Prevalence of severe cerebral edema increased from 2% among subjects with 0-10 min of CPR to 31% among subjects with >40 min of CPR.

CONCLUSION

CPR duration along with easily measurable clinical and resuscitation characteristics predict early severe cerebral edema after OHCA. Future interventional trials should consider targeting or preventing cerebral edema after prolonged hypoxic-ischemic brain injury especially in patients with high risk clinical features.

The Use of Gray-White-Matter Ratios May Help Predict Survival and Neurological Outcomes in Patients Resuscitated From Out-of-Hospital Cardiac Arrest

Background

The gray-white-matter ratio (GWR) measured on brain computed tomography (CT) following return of spontaneous circulation (ROSC) has been reported to be helpful in the prognostication of mortality or comatose status of cardiac arrest victims. However, whether the use of GWR in predicting the outcomes in out-of-hospital cardiac arrest (OHCA) survivors in Taiwan population remains uninvestigated.

Methods

This retrospective observational study conducted in a single tertiary medical center in Taiwan enrolled all the non-traumatic OHCA adults (> 18 years old) with sustained ROSC (≥ 20 minutes) during the period from 2006 to 2014. Patients with following exclusion criteria were further excluded: no brain CT within 24 hours following ROSC; the presence of intracranial hemorrhage, severe old insult, brain tumor, ventriculoperitoneal shunt, and severe image artifact. The GWR values were obtained from the density measurement of bilateral putamen, caudate nuclei, posterior limbs of internal capsule, corpus callosum, medial cortex and medial white matter of cerebrum in Hounsfield unit with region of interest of 0.11 cm², and further compared between the patients who survived to hospital discharge or not and the patients with and without good neurological outcome (good: cerebral performance category [CPC] of 1-2, poor: CPC of 3-5), respectively.

Results

A total of 228 patients were included in the final analysis with 59.2% in male gender and mean age of 65.8-year-old. There were 106 patients (46.5%) survived to hospital discharge and 40 patients (17.5%) discharged with good neurological outcomes. The GWR values of patients who survived to hospital discharge was significantly higher than ones of those who failed (e.g. basal ganglion: 1.239 vs. 1.199, p < 0.001). Patients with good neurological outcome also had higher GWR values than those with poor outcome (e.g. basal ganglion: 1.243 vs. 1.208, p = 0.010). The Area Under Curve of Receiver of Characteristic curve demonstrated fair predicting ability of GWR for survival and neurological outcomes.

Conclusion

The use of GWR measured on bran CT within 24 hours following ROSC can help in predicting survival-to-hospital discharge and neurological outcome in OHCA survivors.

How can neurological outcomes be predicted in comatose pediatric patients after out-of-hospital cardiac arrest?

The prognosis of patients who are comatose after resuscitation remains uncertain. The accurate prediction of neurological outcome is important for management decisions and counseling. A neurological examination is an important factor for prognostication, but widely used sedatives alter the neurological examination and delay the response recovery. Additional studies including electroencephalography, somatosensory-evoked potentials, brain imaging, and blood biomarkers are useful for evaluating the extent of brain injury. This review aimed to assess the usefulness of and provide practical prognostic strategy for pediatric postresuscitation patients. The principles of prognostication are that the assessment should be delayed until at least 72 hours after cardiac arrest and the assessment should be multimodal. Furthermore, multiple factors including unmeasured confounders in individual patients should be considered when applying the prognostication strategy.

Prognostic value of OHCA, C-GRApH and CAHP scores with initial neurologic examinations to predict neurologic outcomes in cardiac arrest patients treated with targeted temperature management

OBJECTIVE

The aim of this study in out-of-hospital cardiac arrest (OHCA) patients treated with targeted temperature management (TTM) was to evaluate the prognostic value of OHCA, C-GRApH, and CAHP scores with initial neurologic examinations for predicting neurologic outcomes.

METHODS

This retrospective study included OHCA patients treated with TTM from 2009 to 2017. We calculated three cardiac arrest (CA)-specific risk scores (OHCA, C-GRApH, and CAHP) at the time of admission. The initial neurologic examination included an evaluation of the Full Outline of UnResponsiveness brainstem reflexes (FOUR_B) and Glasgow Coma Scale motor (GCS_M) scores. The primary outcome was the neurologic outcome at hospital discharge.

RESULTS

Of 311 subjects, 99 (31.8%) had a good neurologic outcome at hospital discharge. The OHCA score had an area under the receiver operating characteristic curve (AUROC) of 0.844 (95% confidence interval (CI): 0.798-0.884), the C-GRApH score had an AUROC of 0.779 (95% CI: 0.728-0.824), and the CAHP score had an AUROC of 0.872 (95% CI: 0.830-0.907). The addition of the FOUR_B or GCS_M score to the OHCA score improved the prediction of poor neurologic outcome (with FOUR_B: AUROC = 0.899, p = 0.001; with GCS_M: AUROC = 0.880, p = 0.004). The results were similar with the C-GRApH and CAHP scores in predicting poor neurologic outcome.

CONCLUSIONS

This study confirms the good prognostic performance of CA-specific scores to predict neurologic outcomes in OHCA patients treated with TTM. By adding new variables associated with the initial neurologic examinations, the prognoses of neurologic outcomes improved compared to the existing scoring models.

Resuscitating the Globally Ischemic Brain: TTM and Beyond

Cardiac arrest (CA) afflicts ~ 550,000 people each year in the USA. A small fraction of CA sufferers survive with a majority of these survivors emerging in a comatose state. Many CA survivors suffer devastating global brain injury with some remaining indefinitely in a comatose state. The pathogenesis of global brain injury secondary to CA is complex. Mechanisms of CA-induced brain injury include ischemia, hypoxia, cytotoxicity, inflammation, and ultimately, irreversible neuronal damage. Due to this complexity, it is critical for clinicians to have access as early as possible to quantitative metrics for diagnosing injury severity, accurately predicting outcome, and informing patient care. Current recommendations involve using multiple modalities including clinical exam, electrophysiology, brain imaging, and molecular biomarkers. This multi-faceted approach is designed to improve prognostication to avoid "self-fulfilling" prophecy and early withdrawal of life-sustaining treatments. Incorporation of emerging dynamic monitoring tools such as diffuse optical technologies may provide improved diagnosis and early prognostication to better inform treatment. Currently, targeted temperature management (TTM) is the leading treatment, with the number of patients needed to treat being ~ 6 in order to improve outcome for one patient. Future avenues of treatment, which may potentially be combined with TTM, include pharmacotherapy, perfusion/oxygenation targets, and pre/postconditioning. In this review, we provide a bench to bedside approach to delineate the pathophysiology, prognostication methods, current targeted therapies, and future directions of research surrounding hypoxic-ischemic brain injury (HIBI) secondary to CA.

Prognosis Value of Gray-White-Matter Ratios in Comatose Survivors After In-Hospital Cardiac Arrest

BACKGROUND

The gray-white-matter ratio (GWR) measured on cerebral non-contrasted computed tomography (NCCT) has been reported to help the prognostication of mortality or comatose status of out-of-hospital cardiac arrest (OHCA) victims. Since the etiologies and resuscitative process differ significantly between patients with OHCA and in-hospital cardiac arrest (IHCA), the predictive ability of GWR in IHCA survivors remains unclear.

METHODS

This retrospective observational study conducted in a single tertiary medical center in Taiwan enrolled all the non-traumatic IHCA adults with sustained return of spontaneous circulation (ROSC) and had received cerebral NCCT examination within 24 hours following cardiac arrest. The GWR of survivor and non-survivor as well as good and poor neurological outcome were analyzed.

RESULTS

A total of 79 IHCA patients with 68.4% in male gender and mean age of 66-year-old were enrolled in the current study. 34 patients (43.0%) survived to hospital discharge and 20 patients (25.3%) were discharged with good neurological outcome. The median GWR of patients with good and poor outcomes in either aspect of survival or neurological function did not show significant difference. The area under the plotted receiver of characteristic curves of each GWR also did not show satisfactory predictive performance.

CONCLUSIONS

The use of GWR for outcome prognosis of patients in emergency department whom progressed to circulatory failure did not show promising result.

Imaging for Neuroprognostication After Cardiac Arrest: Systematic Review and Meta-analysis

BACKGROUND

Predicting neurological outcome in comatose survivors of cardiac arrest relies on clinical findings, radiological and neurophysiological test results. To evaluate the predictive accuracy of brain computed tomography (CT) and magnetic resonance imaging (MRI) for prognostication of neurological outcomes after cardiac arrest.

METHODS

We searched MEDLINE (database inception to August 2018) and included all observational cohort studies or randomized controlled trials including adult (16 years or older) survivors of cardiac arrest which evaluated the diagnostic accuracy of CT or MRI for predicting neurologic outcome or mortality. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. All review stages were conducted independently by 2 reviewers, and where possible data were pooled using bivariate meta-analysis. The main outcome was to evaluate the of accuracy of CT and MRI in neuroprognostication of patients after cardiac arrest.

RESULTS

We included 44 studies that examined brain CT (n = 24) or MRI (n = 21) in 4008 (n per study, 9-398) patients. Decreased grey to white matter ratio on CT (20 studies) was useful for predicting poor neurological outcome (sensitivity 0.44, 95% CI 0.29-0.60; specificity 0.97, 95% CI 0.93-0.99; positive likelihood ratio [LR+] 13.8, 95% CI 6.9-27.7). Similarly, diffusion-weighted imaging (DWI) on MRI (16 studies; sensitivity 0.77, 95% CI 0.65-0.85; specificity 0.92, 95% CI 0.85-0.96; LR+ 9.2, 95% CI 5.2-16.4) and DWI and fluid-attenuated inversion recovery (FLAIR) MRI (4 studies, sensitivity 0.70, 95% CI 0.43-0.88; specificity 0.95, 95% CI 0.79-0.99; LR+ 13.4, 95% CI 3.5-51.2) were useful for predicting poor neurological outcomes. We found marked heterogeneity in timing of radiological examinations and neurological assessments relative to the cardiac arrest.

CONCLUSION

Decreased grey to white matter ratio on CT and DWI or DWI and FLAIR on MRI are useful adjuncts for predicting poor early neurological outcome after cardiac arrest.

Timing of brain computed tomography and accuracy of outcome prediction after cardiac arrest

AIM

Gray-white-matter ratio (GWR) calculated from head CT is a radiologic index of tissue changes associated with hypoxic-ischemic encephalopathy after cardiac arrest (CA). Evidence from previous studies indicates high specificity for poor outcome prediction at GWR thresholds of 1.10-1.20. We aimed to determine the relationship between accuracy of neurologic prognostication by GWR and timing of CT.

METHODS

We included 195 patients admitted to the ICU following CA. GWR was calculated from CT radiologic densities in 16 regions of interest. Outcome was determined upon intensive care unit discharge using the cerebral performance category (CPC). Accuracy of outcome prediction of GWR was compared for 3 epochs (<6, 6-24, and >24 h after CA).

RESULTS

125 (64%) patients had poor (CPC4-5) and 70 (36%) good outcome (CPC1-3). Irrespective of timing, specificity for poor outcome prediction was 100% at a GWR threshold of 1.10. Among 50 patients with both early and late CT, GWR decreased significantly over time (p = 0.002) in patients with poor outcome, sensitivity for poor outcome prediction was 12% (7-20%) with early CTs (<6 h) and 48% (38-58%) for late CTs (>24 h). Across all patients, sensitivity of early and late CT was 17% (9-28%) and 39% (28-51%), respectively.

CONCLUSION

A GWR below 1.10 predicts poor outcome (CPC4-5) in patients after CA with high specificity irrespective of time of acquisition of CT. Because GWR decreases over time in patients with severe HIE, sensitivity for prediction of poor outcome is higher for late CTs (>24 h after CA) as compared to early CTs (<6 h after CA).

Cerebral Edema After Cardiopulmonary Resuscitation: A Therapeutic Target Following Cardiac Arrest?

We sought to review the role that cerebral edema plays in neurologic outcome following cardiac arrest, to understand whether cerebral edema might be an appropriate therapeutic target for neuroprotection in patients who survive cardiopulmonary resuscitation. Articles indexed in PubMed and written in English. Following cardiac arrest, cerebral edema is a cardinal feature of brain injury and is a powerful prognosticator of neurologic outcome. Like other conditions characterized by cerebral ischemia/reperfusion, neuroprotection after cardiac arrest has proven to be difficult to achieve. Neuroprotection after cardiac arrest generally has focused on protecting neurons, not the microvascular endothelium or blood-brain barrier. Limited preclinical data suggest that strategies to reduce cerebral edema may improve neurologic outcome. Ongoing research will be necessary to determine whether targeting cerebral edema will improve patient outcomes after cardiac arrest.

Early whole-body CT for treatment guidance in patients with return of spontaneous circulation after cardiac arrest

PURPOSE

Non-traumatic cardiac arrest (CA) and return of spontaneous circulation (ROSC) after cardiopulmonary resuscitation (CPR) are often associated with multiple pathologies. Expecting a high prevalence of important findings, a whole-body CT (WBCT) could be of relevance for therapy. The aim of this study is to investigate the feasibility and diagnostic yield of an early WBCT in this setting.

METHODS

This single-center retrospective study included 100 consecutive patients (27 female; 73 male; mean age 68.5± 12.57 years) with non-traumatic, in- and out-of-hospital CA and ROSC following CPR, who underwent a contrast-enhanced WBCT within 6 h after ROSC over 12 months. CT findings were determined corresponding to anatomical region.

RESULTS

Early WBCT was successfully carried out in 100% of the patients with CA and ROSC after CPR. Acute pathologies were found not only in the chest but also in the head (15%) and the abdomen (6%). Early global brain edema (n = 12), acute stroke (n = 3), pulmonary embolism (n = 10), pneumothorax (26%), acute abdominal pathologies (n = 6), iatrogenic bleeding (4%), and CPR-related injuries (93%) were detected by CT right from the beginning of the post-cardiac arrest care.

CONCLUSIONS

An early WBCT is feasible and provides added diagnostic value for patients with ROSC after non-traumatic CA.

Prognostication via early computed tomography head in patients treated with targeted temperature management after cardiac arrest

BACKGROUND

We evaluated computed tomography head (CTH) imaging obtained prior to targeted temperature management (TTM) in patients after cardiac arrest, and its role in prognostication.

METHODS

In this retrospective cohort study in a tertiary-care hospital, 341 adults presenting with out-of-hospital cardiac arrest received a CTH prior to TTM. Associations between outcomes and neuroimaging variables were evaluated with Chi-square analysis for significant associations that yielded a composite neuroimaging score-Tennessee Early Neuroimaging Score (TENS). Univariable and multivariable logistic regression analysis including TENS as an independent variable and the four outcome dependent variables were analyzed.

RESULTS

Four of the neuroimaging variables-sulcal effacement, partial gray-white matter effacement, total gray-white matter effacement, deep nuclei effacement-had significant associations with each of the four outcome variables and yielded TENS. In multivariable logistic regression models adjusted for potential confounders, TENS was associated with poor discharge CPC (OR 2.15, 95%CI 1.16-3.98, p = .015), poor disposition (OR 2.62, 95%CI 1.37-5.02, p = .004), in-hospital mortality (OR 1.99, 95%CI 1.09-3.62, p = .024), and ICU mortality (OR 1.89, 95%CI 1.12-3.20, p = .018).

CONCLUSION

Imaging prior to TTM may help identify post-cardiac arrest patients with severe anoxic brain injury and poor outcomes.

Grey-white matter ratio measured using early unenhanced brain computed tomography shows no correlation with neurological outcomes in patients undergoing targeted temperature management after cardiac arrest

AIM

This study evaluated whether the grey-white matter ratio (GWR) assessed via early brain computed tomography (CT) within 2 h after the return of spontaneous circulation (ROSC) following cardiac arrest is associated with poor neurological outcomes after 6 months in post-cardiac arrest patients treated with targeted temperature management (TTM).

METHODS

This study used data from the Korean Hypothermia Network prospective registry obtained from November 2015 to October 2017 to assess patients with out-of-hospital cardiac arrest (OHCA) who underwent brain CT within 2 h following the ROSC. The primary endpoint was the neurological outcome 6 months post-cardiac arrest (cerebral performance category; CPC). The GWR was measured using early brain CT images. The subgroup analysis examined the difference in GWRs obtained from early and repeated brain CT.

RESULTS

Five-hundred-twelve patients were enrolled. Good (CPC 1-2) and poor (CPC 3-5) neurological outcomes were observed in 162 (31.6%) and 350 (68.4%) patients, respectively. The multivariate logistic regression analysis revealed that the GWR measured using early brain CT was a statistically nonsignificant predictor of poor neurologic outcomes (p = 0.727). In patients with poor outcomes, the mean GWR obtained from early and repeated CT images were 1.171 ± 0.058 and 1.091 ± 0.133, respectively (p < 0.001); there was no statistically significant difference between the GWRs in patients with good outcomes.

CONCLUSION

The GWR assessed via early brain CT alone is not an independent factor predictive of poor neurologic outcomes but could be useful when used with repeated CT data.

Multimodal assessment using early brain CT and blood pH improve prediction of neurologic outcomes after pediatric cardiac arrest

BACKGROUND

Early prediction of neurologic prognosis in children resuscitated from cardiac arrest is a major challenge. This study aimed to investigate the usefulness of a combined model based on brain computed tomography (CT) and initial blood gas analysis to predict neurologic prognoses in pediatric patients after cardiac arrest.

METHODS

We retrospectively analyzed the medical records of patients resuscitated after cardiac arrest from 2000 to 2018. Patients aged one month to 18 years were included. Gray to white matter ratio (GWR), ambient cistern effacement (ACE), and blood gas analysis were studied. The primary outcome was neurological prognosis, which was evaluated using the Pediatric Cerebral Performance Category (PCPC) scale at discharge.

RESULTS

Of 97 resuscitated patients, 64 brain CT images were available. Fourteen patients had a good neurologic outcome (PCPC 1-3) and 50 patients a poor neurologic outcome (PCPC 4-6). The multimodal model (AUC 0.897) containing GWR of basal ganglia (BG), ACE, and blood pH was found to be superior for predicting poor neurologic prognosis than single variable models (AUC of GWR-BG: 0.744, ACE: 0.804, pH: 0.747). Interestingly, we found the GWR-BG cutoff value for specificity 100% differed significantly between patients <4 years (cutoff value: 1.08, p = 0.04) and ≥4 years (cutoff value: 1.18, p = 0.004).

CONCLUSIONS

The combination of GWR-BG, ambient cistern effacement, and blood pH was found to usefully predict neurological outcome in children resuscitated from cardiac arrest. In addition, the cutoff value of GWR-BG for the prediction of neurologic outcome was found to increase with age.

Combination of Early EEG, Brain CT, and Ammonia Level Is Useful to Predict Neurologic Outcome in Children Resuscitated From Cardiac Arrest

Purpose: Predicting neurologic prognosis in pediatric patients recovered after cardiac arrest is more difficult than in adults. This study hypothesized that a combination model of early electroencephalography, brain computed tomography (CT), and laboratory findings improve prediction performance of neurologic outcome in pediatric patients after cardiac arrest. Methods: We retrospectively analyzed the medical records of pediatric patients resuscitated after non-traumatic cardiac arrest. Clinical features, electroencephalography, gray matter to white matter attenuation ratio on brain CT, and laboratory findings were analyzed. The primary outcome was neurologic prognosis based on the Pediatric Cerebral Performance Category score. Results: Of 21 patients, seven (33.3%) were classified as a good neurologic outcome group and 14 (66.7%) were classified as a poor neurologic outcome group. The good outcome group was associated with a slow and disorganized electroencephalographic background pattern (P = 0.006), reactivity (P = 0.006), and electrographic seizures (P = 0.03). The frequency of a suppressed electroencephalographic background pattern was significantly higher in the poor outcome group (P = 0.006). The poor outcome group was also associated with a low level of gray matter to white matter attenuation ratio (P = 0.03) and hyperammonemia (P = 0.003). The area under curve of the combined model, consisting of electroencephalographic background, gray matter to white matter attenuation ratio, and ammonia was the highest at 0.959 (0.772-0.999) with a specificity of 100%. Conclusion: Unfavorable electroencephalographic background, low gray matter to white matter attenuation ratio on brain CT, and hyperammonemia are associated with poor neurologic outcome in children after cardiac arrest.

Diagnostic performance of CT densities in selected gray- and white-matter regions for the clinical diagnosis of brain death: A retrospective study in a tertiary-level general hospital

INTRODUCTION

We aimed to determine the diagnostic performance of Hounsfield Units (HUs) in selected brain region using computed tomography for the clinical diagnosis of brain death (BD).

METHODS

A retrospective, case-control study design. A total of 66 subjects (22 cases, 44 controls) underwent brain tomography between January 2011 and December 2016. Inclusion criteria for cases considered patients with a CT performed within the 24 first hours of a clinical diagnosis of brain death. Exclusion criteria applied to patients with no CT scan performed before BD diagnosis. Brain-healthy-control subjects were identified from the hospital's CT scan database. We selected 12 regions for each cerebral hemisphere (4 basal ganglia; 2 regions gray matter (GM) regions; 4 white matter (WM) regions; 2 brain stem regions); two GM and WM regions in each cerebellar hemisphere, and 4 GM/WM ratios. Measurements included analysis of variance, receiver operating characteristic (ROC) curve, and of pooled effect sizes.

RESULTS

72 measures per subject were recorded. Without contrast material, the best performance was the GM/WM ratio at the basal ganglia level (AUROC = 0.893, 95% C.I. = 0.83, 0.96; p-value <.001). After contrast enhancement, the greatest AUROC value corresponded to the thalamus (AUROC = .959, 95% C.I. = .93, .99; p-value < .001).

CONCLUSIONS

There is not an absolute threshold of GM-WM differentiation below which all patients are diagnosed with BD, but a group of HUs in selected brain regions, some of them with very high sensitivity and specificity to be used as early predictors of BD.

Changes in the gray and white matter of patients with ischemic-edematous insults after traumatic brain injury

OBJECTIVE

Gray matter (GM) and white matter (WM) are vulnerable to ischemic-edematous insults after traumatic brain injury (TBI). The extent of secondary insult after brain injury is quantifiable using quantitative CT analysis. One conventional quantitative CT measure, the gray-white matter ratio (GWR), and a more recently proposed densitometric analysis are used to assess the extent of these insults. However, the prognostic capacity of the GWR in patients with TBI has not yet been validated. This study aims to test the prognostic value of the GWR and evaluate the alternative parameters derived from the densitometric analysis acquired during the acute phase of TBI. In addition, the prognostic ability of the conventional TBI prognostic models (i.e., IMPACT [International Mission for Prognosis and Analysis of Clinical Trials in TBI] and CRASH [Corticosteroid Randomisation After Significant Head Injury] models) were compared to that of the quantitative CT measures.

METHODS

Three hundred patients with TBI of varying ages (92 pediatric, 94 adult, and 114 geriatric patients) and admitted between 2008 and 2013 were included in this retrospective cohort study. The normality of the density of the deep GM and whole WM was evaluated as the proportion of CT pixels with Hounsfield unit values of 31-35 for GM and 26-30 for WM on CT images of the entire supratentorial brain. The outcome was evaluated using the Glasgow Outcome Scale (GOS) at discharge (GOS score ≤ 3, n = 100).

RESULTS

Lower proportions of normal densities in the deep GM and whole WM indicated worse outcomes. The proportion of normal WM exhibited a significant prognostic capacity (area under the curve [AUC] = 0.844). The association between the outcome and the normality of the WM density was significant in adult (AUC = 0.792), pediatric (AUC = 0.814), and geriatric (AUC = 0.885) patients. In pediatric patients, the normality of the overall density and the density of the GM were indicative of the outcome (AUC = 0.751). The average GWR was not associated with the outcome (AUC = 0.511). IMPACT and CRASH models showed adequate and reliable performance in the pediatric and geriatric groups but not in the adult group. The highest overall predictive performance was achieved by the densitometry-augmented IMPACT model (AUC = 0.881).

CONCLUSIONS

Both deep GM and WM are susceptible to ischemic-edematous insults during the early phase of TBI. The extent of the secondary injury was better evaluated by analyzing the normality of the deep GM and WM rather than by calculating the GWR.

Gray-to-white matter ratio predicts long-term recovery potential of patients with aneurysmal subarachnoid hemorrhage

Predicting recovery potential of patients with aneurysmal subarachnoid hemorrhage (aSAH) is challenging. We investigated whether the gray-to-white matter ratio (GWR) predicts recovery of cognitive function (CF) and quality of life (QOL) of these patients. We analyzed data of 69 patients with aSAH. Patients' demographics, comorbidities, and neurological status were recorded. One year after aSAH, Montreal Cognitive Assessment (MoCA) and Short Form-36 (SF-36) tests were administered to the patients, and brain volumes of patients were examined using MRI. Three years after aSAH, MoCA and SF-36 tests were conducted again. Differences between the test scores 1 and 3 years after aSAH were evaluated (ΔMoCA and ΔSF-36). Patients with ΔMoCA ≥ 4 points and those with ΔSF-36 ≥ 8 points were referred to as good MoCA and SF-36 recovery, respectively. ΔMoCA correlated with GWR in male and female patients (females: p < 0.001, R² = 0.581; males: p < 0.001, R² = 0.481). In female patients, GWR > 1.34 predicted good MoCA recovery with 82.3% sensitivity and 80% specificity, and in male patients, GWR > 1.36 predicted good MoCA recovery with 80% sensitivity and 95% specificity. ΔSF-36 correlated with GWR in male and female patients (females: p < 0.001, R² = 0.479; males: p < 0.001, R² = 0.627). In female patients, GWR > 1.35 predicted good SF-36 recovery with 74% sensitivity and 84% specificity, and in male patients, GWR > 1.38 predicted good SF-36 recovery with 72% sensitivity and 92% specificity. GWR is a good predictor of the recovery of CF and QOL in patients with aSAH and, thus, can help physicians to better organize rehabilitation of patients.

Brain imaging in comatose survivors of cardiac arrest: Pathophysiological correlates and prognostic properties

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 mm²/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.

Gray matter to white matter ratio for predicting neurological outcomes in patients treated with target temperature management after cardiac arrest: A systematic review and meta-analysis

AIMS

This study aimed to evaluate the prognostic accuracy of the gray matter to white matter ratio (GWR) in predicting neurological outcomes in post-cardiac arrest patients treated with target temperature management.

DATA SOURCES

We systematically searched MEDLINE and EMBASE (Search date: 09/13/2017). Included studies were those evaluating neurological outcomes using the cerebral performance categories scale. We performed a subgroup analysis based on the location of the measurement. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess the risk of bias.

RESULTS

In total, 1150 patients from 10 observational studies were included. GWR of the basal ganglia (BG) average showed the highest value (area under the curve [AUC] 0.96, SE 0.02, Q 0.90) compared with the putamen/posterior limb of internal capsule (AUC 0.93, SE 0.05, Q 0.87), overall average (AUC 0.91, SE 0.02, Q 0.85), and cerebrum (AUC 0.89, SE 0.05, Q 0.82) for prognostic accuracy. Furthermore, the highest pooled diagnostic odd ratio of GWR for predicting poor neurological outcomes was shown for the BG average (21.00, 95% CI 6.85-64.40) followed by the overall average (20.71, 95% CI 9.53-44.98), putamen/posterior limb of internal capsule (16.08, 95% CI 4.36-59.23), and cerebrum (13.96, 95% CI 4.26-45.76).

CONCLUSIONS

GWR in the early cranial computed tomography scan had high prognostic value in predicting poor neurological outcomes in post-cardiac arrest patients. The BG GWR had the highest prognostic accuracy when compared to other locations of the brain.

Prognostication after cardiac arrest

Hypoxic-ischaemic brain injury (HIBI) is the main cause of death in patients who are comatose after resuscitation from cardiac arrest. A poor neurological outcome-defined as death from neurological cause, persistent vegetative state, or severe neurological disability-can be predicted in these patients by assessing the severity of HIBI. The most commonly used indicators of severe HIBI include bilateral absence of corneal and pupillary reflexes, bilateral absence of N₂O waves of short-latency somatosensory evoked potentials, high blood concentrations of neuron specific enolase, unfavourable patterns on electroencephalogram, and signs of diffuse HIBI on computed tomography or magnetic resonance imaging of the brain. Current guidelines recommend performing prognostication no earlier than 72 h after return of spontaneous circulation in all comatose patients with an absent or extensor motor response to pain, after having excluded confounders such as residual sedation that may interfere with clinical examination. A multimodal approach combining multiple prognostication tests is recommended so that the risk of a falsely pessimistic prediction is minimised.

Association Between Gray-White Matter Ratio in Computed Tomography and Outcome in Patients with Extra-Axial Hematoma

OBJECTIVE

To evaluate relationship between gray-white matter ratio (GWR) on computed tomography and prognosis in patients with extra-axial hematoma.

METHODS

Patients with extra-axial hematoma who had undergone surgical treatment at Qinghai Provincial People's Hospital from September 2016 to December 2017 were included. GWR values were calculated by measuring values of gray matter and white matter in Hounsfield units in noninjury sites of basal ganglia. According to Glasgow Outcome Scale score at 3 months after operation, patients were divided into good prognosis (Glasgow Outcome Scale score 4-5) and poor prognosis (Glasgow Outcome Scale score 1-3) groups.

RESULTS

Of 103 patients who met inclusion criteria and were analyzed, 24 had with a poor outcome, including 5 deaths, and 79 patients had a good outcome. There were significant differences between the 2 groups in terms of age, type of hematoma, admission Glasgow Coma Scale score, and presence of hernia (all P < 0.05). Postoperative HU values of posterior capsule, postoperative GWR values, and difference between preoperative and postoperative GWR values had statistical significance (all P < 0.05). Receiver operating characteristic curve showed that difference between preoperative and postoperative GWR values was the best predictor of poor outcome.

CONCLUSIONS

The difference between preoperative or postoperative GWR values has a higher sensitivity and greater area under the curve to predict patient outcome. Measuring the difference between preoperative and postoperative GWR values may be useful as an objective early predictor of outcome in patients with extra-axial hematoma. Larger samples and multicenter prospective studies are still required.

Relation of gray-white matter ratio with long-term cognitive functions and quality of life in patients with mild to moderate aneurysmal subarachnoid hemorrhage: a prospective observational study

BACKGROUND

In the present study, we hypothesized that a low gray matter-white matter ratio (GWR) is associated with poor cognitive function and low quality of life in patients with mild to moderate (WFNS ≤3) aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

All patients with aSAH who were admitted to the neurointensive care unit (Neuro ICU) and whose WFNS score was ≤ 3 were enrolled in the study. During the Neuro ICU follow-up period, the following variables were recorded: demographics, neurological status, comorbidities, time elapsed between onset of bleeding and Neuro ICU admission, treatment method, number of days with vasospasm symptoms (DVS) and vasopressor usage. One year after bleeding, all patients except those who could not answer the questionnaires appropriately were administered the MoCA and SF-36 tests, and brain magnetic resonance imaging and then volumetric brain analysis were performed.

RESULTS

Eighty-two patients completed the study. One year after aSAH, cognitive dysfunction and low quality of life were observed in 59.8% and 25.6% of patients, respectively. Among the variables obtained during Neuro ICU follow-up, DVS was found to be a major risk factor for cognitive dysfunction (OR: 3.9, 95% CI: 1.9-7.8; p < 0.001), poor quality of life (OR: 2.8, 95% CI: 1.4-5.3, p = 0.002) and a lower GWR value (p < 0.001, correlation coefficient = -0.410, R2 = 0.234). One year after aSAH, higher GWR values were associated with higher MoCA (R2 = 0.506 for males, R2 = 0.413 for females) and SF-36 (R2 = 0.270 for males, R2 = 0.364 for females) scores in both genders. Also, GWR ≤ 1.35 in males and GWR ≤1.33 in females indicated MoCApoor patients with over 80% specificity and sensitivity.

CONCLUSION

GWR has good correlation with the MoCA and SF-36 score, and a low GWR can indicate cognitive dysfunction. In this context, GWR can be used as an additional method to evaluate cognitive function and quality of life.

Neurological Prognostications for the Therapeutic Hypothermia among Comatose Survivors of Cardiac Arrest

Background

Currently, there are limited data of prognostic clues for neurological recovery in comatose survivors undergoing therapeutic hypothermia (TH). We aimed to evaluate clinical signs and findings that could predict neurological outcomes, and determine the optimal time for the prognostication.

Materials and Methods

We retrospectively reviewed database of postarrest survivors treated with TH in our hospital from 2006 to 2014. Cerebral performance category (CPC), neurological signs and findings in electroencephalography (EEG) and brain computed tomography (CT) were evaluated. In addition, the optimal time to evaluate neurological status was analyzed.

Results

TH was performed in 51 postarrest patients. Approximately 53% of TH patients survived at discharge and 33% of the hospital survivors had favorable outcome (CPC1-2). The prognostic clues for unfavorable outcome (CPC3-5) at discharge were lack of pupillary light response (PLR) and/or gag reflex after rewarming, and the absence of at least one of the brainstem reflexes, no eye-opening, or abnormal motor response on the 7^th day. Myoclonus and seizure could not be used to indicate poor prognosis. In addition, prognostic values of EEG and CT findings were inconclusive.

Conclusions

Our study showed the simple neurological signs helped predict short-term neurological prognosis. The most reliable sign determining unfavorable outcome was the lack of PLR. The optimal time to assess prognosis was either at 48-72 h or 7 days after return of spontaneous circulation.

Head computed tomography for prognostication of poor outcome in comatose patients after cardiac arrest and targeted temperature management

INTRODUCTION

A multimodal approach to prognostication of outcome after cardiac arrest (CA) is recommended. Evidence for combinations of methods is low. In this post-hoc analysis we described findings on head computed tomography (CT) after CA. We also examined whether generalised oedema on CT alone or together with the biomarker Neuron-specific enolase (NSE) could predict poor outcome.

METHODS

Patients participating in the Target Temperature Management after out-of-hospital-cardiac-arrest-trial underwent CT based on clinical indications. Findings were divided into pre-specified categories according to local radiologists descriptions. Generalised oedema alone and in combination with peak NSE at either 48h or 72h was correlated with poor outcome at 6 months follow-up using the Cerebral Performance Category (CPC 3-5).

RESULTS

356/939 (37.9%) of patients underwent head CT. Initial CT≤24h after CA was normal in 174/218 (79.8%), whilst generalised oedema was diagnosed in 21/218 (9.6%). Between days 1-7, generalised oedema was seen in 65/143 (45.5%), acute/subacute infarction in 27/143 (18.9%) and bleeding in 9/143 (6.3%). Overall, generalised oedema predicted poor outcome with 33.6% sensitivity (95%CI:28.1-39.5) and 98.4% specificity (95%CI:94.3-99.6), whilst peak NSE demonstrated sensitivities of 61.5-64.8% and specificity 95.7% (95%CI:89.5-98.4). The combination of peak NSE>38ng/l and generalised oedema on CT predicted poor outcome with 46.0% sensitivity (95%CI:36.5-55.8) with no false positives. NSE was significantly higher in patients with generalised oedema.

CONCLUSION

In this study, generalised oedema was more common >24h≤7d after CA. The combination of CT and NSE improved sensitivity and specificity compared to CT alone, with no false positives in this limited population.

Comparison of brain computed tomography and diffusion-weighted magnetic resonance imaging to predict early neurologic outcome before target temperature management comatose cardiac arrest survivors

AIM

We previously reported that diffusion-weighted magnetic resonance imaging (DW-MRI) could be used to predict neurologic outcomes before targeted temperature management (TTM) after return of spontaneous circulation (ROSC) from cardiac arrest (CA). We compared the efficacy of brain computed tomography (CT) and DW-MRI to predict neurologic outcome before TTM in comatose cardiac arrest survivors.

METHODS

We performed a retrospective study of CA patients treated with TTM. The brain CT and DW-MRI were both obtained before TTM. We analysed the grey matter to white matter ratio (GWR) on the brain CT and the presence of high signal intensity on DW-MRI, alone or in combination, to predict poor neurologic outcome (CPC 3-5).

RESULTS

Of 47 comatose CA patients treated with TTM, 39 patients with brain CT and DW-MRI data were included. Median time from the ROSC to the brain CT and DW-MRI was 90min (52-150) and 175min (118-240), respectively. There was no significant difference in predicting poor neurologic outcome between average GWR (area under the curve [AUC] 0.891, sensitivity/specificity 78.8%/100%) and DW-MRI (AUC 0.894, sensitivity/specificity 75.8%/100%) (p=0.963). The combination of average GWR and DW-MRI (AUC 0.939, sensitivity/specificity 87.9%/100%) improved the prediction of poor neurologic outcome rather than each one alone and in other combinations.

CONCLUSION

Our preliminary finding suggests that DW-MRI is potentially useful for early prediction of neurologic outcome (i.e., before TTM) in CA patients. The combination of GWR on brain CT and that on DW-MRI, rather than on each modality alone, appears to improve the sensitivity for predicting neurologic outcome after ROSC from CA. Large prospective multicenter studies should be conducted to confirm these results.