Gray-white Matter Ratio Research Articles

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

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

The prognostic value of gray–white matter ratio on brain computed tomography in adult comatose cardiac arrest survivors

BackgroundRecent studies suggested that the gray–white matter ratio (GWR) determined from brain computed tomography (CT) scans may be a reliable predictor of poor neurological outcomes. The aim of study was to evaluate the association between the GWR and the outcomes in adult comatose cardiac arrest (CA) survivors in Chinese. MethodsA total of 58 CA patients who had CT scans within 72 h of resuscitation between January 2011 and December 2015 were included in this single-center retrospective study. Gray and white matter attenuations (Hounsfield units) were measured, and the GWRs were calculated according to previous studies. The study analyzed the prognostic values of the GWRs in predicting poor outcomes (Cerebral Performance Category 3–5). ResultsThe attenuation values of gray matter were significantly higher in the good outcome group than in the poor one. All GWRs were significantly higher in the good outcome group (p < 0.05). A GWR (basal ganglia) < 1.18 predicted poor outcomes with a sensitivity and specificity of 50.0% and 87.5%, respectively (p = 0.021). GWR (cerebrum) showed the best predictive performance when CT was performed within 24–72 h (p = 0.003). No significant differences were found between GWR and poor outcomes when CT was performed within the first 24 h. ConclusionLow GWRs which were obtained from brain CT scans in comatose CA patients after restoration of spontaneous circulation were associated with poor neurological outcomes. GWR from brain CT can be a useful parameter for prognostic prediction aiding to an optimal clinical decision process in comatose CA survivors.

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.

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). 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. 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. 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 prognostic value of gray-white-matter ratio in patients after respiratory and cardiac arrest

To evaluate the role of gray-white-matter ratio (GWR) on neurological outcome in patients with coma after cardiopulmonary resuscitation (CPR) post-respiratory and cardiac arrest (CA). Respiratory and CA patients with restoration of spontaneous circulation (ROSC) and coma after CPR admitted to Nanjing Drum Tower Hospital Clinical Medical College of Nanjing Medical University from February 2013 to June 2016 were enrolled. All patients were subjected to target temperature management (TTM) after CPR, and received cranial CT within 5 days after ROSC. Attenuation (hounsfield units) was measured at special sites (basal ganglia, centrum semiovale), and specific locus (caudate nucleus, put amen, corpus callosum, posterior limb of internal capsule, medial cortex, medial white matter). The GWR was calculated for basal ganglia and cerebrum. Neurological outcome was judged according to the Glasgow-Pittsburgh cerebral performance category (CPC) at 3 months after ICU discharge. CPC 1-3 were divided into good prognosis, CPC 4-5 were divided into poor prognosis. The receiver-operating characteristic (ROC) curve was drawn to evaluate the prognostic value of GWR in patients with respiratory and CA. Forty-three patients were enrolled, including 26 males and 17 females; age (63±15) years old; 14 good prognosis and 29 poor prognosis. Compared with the good prognosis group, the basal ganglia GWR (GWRbg) and the average GWR (GWRav) were significantly lowered in the poor prognosis group (1.064±0.103 vs. 1.163±0.818, 1.068±0.087 vs. 1.128±0.071, both P < 0.05), the centrum semiovale GWR (GWRce) was similar to that in the good prognosis group (1.072±0.077 vs. 1.092±0.075, P > 0.05). It was shown by ROC curve analysis that the GWRbg, GWRav could evaluate the neurological outcomes of patients, but GWRce could not. The area under the ROC curve (AUC) of GWRbg was 0.756 [95% confidence interval (95%CI) = 0.607-0.905, P = 0.007], the cut-off value was 1.13, the sensitivity was 71.4%, and specificity was 69.0%; the AUC of GWRav was 0.701 (95%CI = 0.532-0.869, P = 0.035), the cut-off value was 1.13, the sensitivity was 71.4%, and specificity was 65.5%; the AUC of GWRce was 0.590 (95%CI = 0.405-0.775, P = 0.344). Respiratory and CA patients receiving TTM with high GWR had favorable neurological outcome. GWR, especially GWRbg could provide help for clinical treatment and prognostic value of survival after CA.

The prognostic value of gray-white matter ratio on brain computed tomography in comatose adult survivors from cardiac arrest

Objective To evaluate the correlation between the gray-white matter ratio (GWR) and the outcomes of comatose adult survivors from cardiac arrest (CA) in Chinese. Methods Sixty-one CA patients checked with CT scans within 72 hours of resuscitation from January 2011 to January 2016 were included in this single-center retrospective study. Gray and white matter density (Hounsfield units) were measured, and the GWRs were calculated according to previous studies. The prognostic values of the GWRs in predicting poor outcomes (Cerebral Performance Category 3-5) were analyzed. Results The density values of gray matter were significantly higher in the good outcome group than those in the poor one. All GWRs were significantly higher in the good outcome group (P < 0.05). A GWR (basal ganglia) < 1.18 predicted poor outcomes with a sensitivity and specificity of 50.0% and 88.2%, respectively (P = 0.012). Conclusions Low GWRs, determined from brain CT scans in comatose CA patients after resuscitation, were associated with poor neurological outcomes. GWR determination from brain CT can be a useful indicator for outcome prediction aiding in an optimal clinical decision process in comatose survivors from CA. Key words: Cardiac arrest; Coma; Computed tomography; Gray-white matter ratio; Prognosis

Useful Computed Tomography Score for Estimation of Early Neurologic Outcome in Post-Cardiac Arrest Patients With Therapeutic Hypothermia.

The Alberta Stroke Program Early CT Score (ASPECTS) is used to assess early ischemic stroke damage. This study compared bilateral ASPECTS (ASPECTS-b) with the gray:white matter ratio (GWR) and quantitative regional abnormality (QRA) to evaluate the prognostic utility of early computed tomography (CT) findings in post-cardiac arrest patients.Methods and Results:Out-of-hospital cardiac arrest patients with return of spontaneous circulation (ROSC) who underwent brain CT (<6 h after onset) and therapeutic hypothermia were recruited from a university hospital over a 2-year period. General demographics, ROSC characteristics, ASPECTS-b (total score=20 points), GWR, and QRA were assessed. Multivariate logistic regression analysis was used to predict neurologic outcome using cerebral performance category (CPC) at 1 month. The study population was divided into good (n=20; CPC 1-2) and poor (n=47; CPC 3-5) outcome groups. The good (vs. poor) outcome group was younger (mean [±SD] age 46.7±11.8 vs. 60.3±17.2 years; P=0.002) and had more initial shockable rhythms (40.0% vs. 8.5%; P=0.002). In addition, the good outcome group had a higher mean ASPECTS-b score (15.3±2.7 vs. 9.0±4.9; P<0.001), despite no differences in QRA and mean GWR. Age and ASPECTS-b were independent predictors of outcome after adjusting for potential confounders. These findings suggest that an initial CT score (ASPECTS-b) could help estimate early neurologic outcomes in post-cardiac arrest patients treated with therapeutic hypothermia.

Automated assessment of early hypoxic brain edema in non-enhanced CT predicts outcome in patients after cardiac arrest

Abstract Introduction Early prediction of potential neurological recovery in patients after cardiac arrest is challenging. Recent studies suggest that the densitrometic gray-white matter ratio (GWR) determined from cranial computed tomography (CT) scans may be a reliable predictor of poor outcome. We evaluated an automated, rater independent method to determine GWR in CT as an early objective imaging predictor of clinical outcome. Methods We analyzed imaging data of 84 patients after cardiac arrest that underwent noncontrast CT within 24h after arrest. To determine GWR in CT we applied two methods using a recently published automated probabilistic gray-white matter segmentation algorithm (GWR_aut) and conventional manual measurements within gray-white regions of interest (GWR_man). Neurological outcome was graded by the cerebral performance category (CPC). As part of standard routine CPC was assessed by the treating physician in the intensive care unit at admission and at discharge to normal ward. The performance of GWR measures (automated and manual) to predict the binary clinical endpoints of poor (CPC3–5) and good outcome (CPC1–2) was assessed by ROC analysis with increasing discrimination thresholds. Results of GWR_aut were compared to GWR_man of two raters. Results Of 84 patients, 55 (65%) showed a poor outcome. ROC curve analysis revealed reliable outcome prediction of GWR_aut (AUC 0.860) and GWR_man (AUC 0.707 and 0.699, respectively). Predictive power of GWR_aut was higher than GWR_man by each rater ( p =0.019 and p =0.021, respectively) at an optimal cut-off of 1.084 to predict poor outcome (optimal criterion with 92.7% sensitivity, 72.4% specificity). Interrater reliability of GWR_man by intra-class correlation coefficient (ICC) was moderate (0.551). Conclusion Automated quantification of GWR in CT may be used as an objective observer-independent imaging marker for outcome in patients after cardiac arrest.

Automated assessment of early hypoxic brain edema in non-enhanced CT predicts outcome in patients after cardiac arrest

IntroductionEarly prediction of potential neurological recovery in patients after cardiac arrest is challenging. Recent studies suggest that the densitrometic gray-white matter ratio (GWR) determined from cranial computed tomography (CT) scans may be a reliable predictor of poor outcome. We evaluated an automated, rater independent method to determine GWR in CT as an early objective imaging predictor of clinical outcome. MethodsWe analyzed imaging data of 84 patients after cardiac arrest that underwent noncontrast CT within 24h after arrest. To determine GWR in CT we applied two methods using a recently published automated probabilistic gray-white matter segmentation algorithm (GWR_aut) and conventional manual measurements within gray-white regions of interest (GWR_man). Neurological outcome was graded by the cerebral performance category (CPC). As part of standard routine CPC was assessed by the treating physician in the intensive care unit at admission and at discharge to normal ward. The performance of GWR measures (automated and manual) to predict the binary clinical endpoints of poor (CPC3–5) and good outcome (CPC1–2) was assessed by ROC analysis with increasing discrimination thresholds. Results of GWR_aut were compared to GWR_man of two raters. ResultsOf 84 patients, 55 (65%) showed a poor outcome. ROC curve analysis revealed reliable outcome prediction of GWR_aut (AUC 0.860) and GWR_man (AUC 0.707 and 0.699, respectively). Predictive power of GWR_aut was higher than GWR_man by each rater (p=0.019 and p=0.021, respectively) at an optimal cut-off of 1.084 to predict poor outcome (optimal criterion with 92.7% sensitivity, 72.4% specificity). Interrater reliability of GWR_man by intra-class correlation coefficient (ICC) was moderate (0.551). ConclusionAutomated quantification of GWR in CT may be used as an objective observer-independent imaging marker for outcome in patients after cardiac arrest.

Prognostication of outcome after cardiac arrest and targeted temperature management

The vast majority of cardiac arrest (CA) survivors remain comatose at hospital arrival. Around one-half of these patients suffer from severe hypoxic encephalopathy leading to death or unresponsive wakefulness. Early outcome prognostication may reduce futile intensive care and suffering for next of kin. Several early prognostic markers have shown high positive predictive value for poor outcome in patients treated at normothermia, but results may be altered by targeted temperature management (TTM). Most prominently, absent motor response to painful stimuli 3 days after CA and a serum concentration of neuron-specific enolase (NSE) above 33 ng/ml do not predict poor outcome reliably in these patients [1,2]. Sedation during TTM is a relevant confounder for motor response and corneal reflexes [3]. Bilaterally absent pupillary light reaction 3 days after CA is a reliable predictor of poor outcome (sensitivity 20%) [1]. Eye diseases and medication are potential confounders. A threshold for poor outcome prediction by NSE has not been established after TTM. Above a level of 80 to 100 ng/ml 72 hours after CA good outcome has rarely been reported. The NSE levels may vary with different test kits, and NSE producing tumors, acute brain diseases and severe hematological diseases/hemolysis are confounders. Bilateral absence of cortical median nerve SSEP remains a reliable predictor, but single cases with recovery were reported [4] and inter-rater reliability is not perfect. Preserved spinal SSEP and low cortical noise levels are important prerequisites. The sensitivity of absent SSEP for poor outcome prediction is around 40% [1]. EEG can be a valuable predictive tool when interpreted by experienced neurophysiologists and indicates (subclinical) status epilepticus [5]. The influence of medication on EEG needs to be considered. Recently, a revised EEG classification has been proposed [6]. A reduced contrast between gray and white matter in brain computed tomography is associated with poor outcome. It can be quantified as gray–white-matter ratio and values below 1.1 predict poor outcome with high specificity [7]. Additional studies are needed to establish this threshold more firmly. MRI emerges as a prognostic parameter because of high spatial resolution and high sensitivity for cytotoxic brain edema with DWI/ADC imaging [8]. However, access is limited and quantification of early changes needs to be established in larger cohorts. To date, most authors argue for a multiparameter prognostication approach including repeated neurological examination, SSEP, NSE, EEG and imaging (CT or MRI) combined with a waiting period for potential recovery of several days after cardiac arrest.

Outcome Prediction in Patients After Cardiac Arrest: A Simplified Method for Determination of Gray–White Matter Ratio in Cranial Computed Tomography

Out-of-hospital cardiac arrest is a frequent cause of death in Europe. Hypoxic ischemic encephalopathy (HIE) often develops in initial survivors, and the question of treatment limitation arises in severely affected patients. To establish a poor prognosis with a high level of certainty, the use of a combination of prognostic parameters such as neurological examination, somatosensory evoked potentials, and neuron-specific enolase is common practice. A few recent studies suggest that gray-white matter ratio (GWR) determined from cranial computed tomography (CT) scans is an additional reliable predictor of poor prognosis. The standard GWR determination method involves measurements of 16 different regions of interest (ROIs). We tested whether a simplified method to obtain GWR has equivalent reliability for poor outcome prediction. We retrospectively analyzed 98 patients after cardiac arrest who had been treated with hypothermia. CT scans were obtained within the first 7 days after cardiac arrest. Neurological outcome was determined at intensive care unit discharge. Four different methods to obtain GWR were compared in a receiver-operating characteristic curve analysis with respect to their prognostic value for poor outcome prediction. The simplest method using only four ROIs (putamen and internal capsule bilaterally) had the same prognostic value compared with the standard method using 16 ROIs. The simplified GWR predicted poor outcome with a sensitivity of 44 % at 100 % specificity. Our results indicate that for poor outcome prediction in survivors of cardiac arrest, a simplified GWR determination is feasible and has the same reliability as the complex standard procedure.

The effects of prenatal sex steroid hormones on sexual differentiation of the brain

Most of the anatomical, physiological and neurochemical gender-related differences in the brain occur prenatally. The sexual differences in the brain are affected by sex steroid hormones, which play important roles in the differentiation of neuroendocrine system and behavior. Testosterone, estrogen and dihydrotestosterone are the main steroid hormones responsible for the organization and sexual differentiation of brain structures during early development. The structural and behavioral differences in the female and male brains are observed in many animal species; however, these differences are variable between species. Animal and human (in vivo imaging and postmortem) studies on sex differences in the brain have shown many differences in the local distribution of the cortex, the gray-white matter ratio, corpus callosum, anterior commissure, hypothalamus, bed nucleus of the stria terminalis, limbic system and neurotransmitter systems. This review aims to evaluate the anatomical, physiological and neurochemical differences in the female and male brains and to assess the effect of prenatal exposure to sex steroid hormones on the developing brain.

The prognostic value of gray-white-matter ratio in cardiac arrest patients treated with hypothermia

BackgroundMild therapeutic hypothermia alters the validity of a number of parameters currently used to predict neurological outcome after cardiac arrest and resuscitation. Thus, additional parameters are needed to increase certainty of early prognosis in these patients. A promising new approach is the determination of the gray-white-matter ratio (GWR) in cranial computed tomography (CCT) obtained early after resuscitation. It is not known how GWR relates to established outcome parameters such as neuron specific enolase (NSE) or somatosensory evoked potentials (SSEP).MethodsCardiac arrest patients (n = 98) treated with hypothermia were retrospectively analyzed with respect to the prognostic value of GWR, NSE and SSEP.ResultsA GWR < 1.16 predicted poor outcome with 100% specificity and 38% sensitivity. In 62 patients NSE, SSEP and CCT were available. The sensitivity of poor outcome prediction by both NSE > 97 μg/L and bilateral absent SSEP was 43%. The sensitivity increased to 53% in a multi-parameter approach predicting poor outcome using at least two of the three parameters (GWR, NSE and SSEP).ConclusionOur results suggest a strong association of a low GWR with poor outcome following cardiac arrest. Determination of the GWR increases the sensitivity in a multi-parameter approach for prediction of poor outcome after cardiac arrest.

The Relation between Neurologic Prognosis and Optic Nerve Sheath Diameter Measured in Initial Brain Computed Tomography of Cardiac Arrest and Hanging Patients

Background: Early prediction of neurologic outcome is important to patients treated with therapeutic hypothermia after hypoxic brain injury. Hypoxic brain injury patients may have poor neurologic prognosis due to increased intracranial pressure. Increased intracranial pressure can be detected by optic nerve sheath diameter (ONSD) measurement in computed tomography (CT) or ultrasound. In this study, we evaluate the relation between neurologic prognosis and optic nerve sheath diameter measured in brain CT of hypoxic brain injury patients. Methods: We analyzed the patient clinical data by retrospective chart review. We measured the ONSD in initial brain CT. We also measured and calculated the gray white matter ratio (GWR) in CT scan. We split the patients into two groups based on neurologic outcome, and clinical data, ONSD, and GWR were compared in the two groups. Results: Twenty-four patients were included in this study (age: 52.6 ± 18.3, 18 males). The mean ONSD of the poor neurologic outcome group was larger than that of the good neurologic outcome group (6.07 mm vs. 5.39 mm, p = 0.003). The GWR of the good neurologic outcome group was larger than that of the poor outcome group (1.09 vs. 1.28, p = 0.000). ONSD was a good predictor of neurologic outcome (area under curve: 0.848), and an ONSD cut off ≥ 5.575 mm had a sensitivity of 86.7% and a specificity of 77.8%. Conclusions: ONSD measured on the initial brain CT scan can predict the neurologic prognosis in cardiac arrest and hanging patients treated with therapeutic hypothermia.

Early time points perfusion imaging: relative time of arrival, maximum derivatives and fractional derivatives.

Time of arrival (TOA) of a bolus of contrast agent to the tissue voxel is a reference time point critical for the Early Time Points Perfusion Imaging Method (ET) to make relative cerebral blood flow (rCBF) maps. Due to the low contrast to noise (CNR) condition at TOA, other useful reference time points known as relative time of arrival data points (rTOA) are investigated. Candidate rTOA's include the time to reach the maximum derivative, the maximum second derivative, and the maximum fractional derivative. Each rTOA retains the same relative time distance from TOA for all tissue flow levels provided that ET's basic assumption is met, namely, no contrast agent has a chance to leave the tissue before the time of rTOA. The ET's framework insures that rCBF estimates by different orders of the derivative are theoretically equivalent to each other and monkey perfusion imaging results supported the theory. In rCBF estimation, maximum values of higher order fractional derivatives may be used to replace the maximum derivative which runs a higher risk of violating ET's assumption. Using the maximum values of the derivative of orders ranging from 1 to 1.5 to 2, estimated rCBF results were found to demonstrate a gray-white matter ratio of approximately 3, a number consistent with flow ratio reported in the literature.

Prefrontal gray and white matter volumes in healthy aging and Alzheimer disease.

To quantify the contribution of gray and white matter volumes to total prefrontal volume in healthy aging. To determine if prefrontal tissue volumes distinguish healthy aging from Alzheimer disease (AD). Volumes of total prefrontal cortex, prefrontal gray matter, and prefrontal white matter were compared among young healthy elderly (YHE) (n = 14; mean age, 70 years), old healthy elderly (OHE) (n = 14; mean age, 90 years), and subjects with AD (n = 14; mean age, 70 years) by analysis of variance. Additionally, Pearson correlations were performed between volumes and age. Old healthy elderly and subjects with AD had significantly less total prefrontal volume (approximately 15% less in both groups) and prefrontal white matter volume (approximately 30% less and 20% less in the OHE and AD groups, respectively) than YHE, but there were no differences between the OHE and AD groups. There was a significant difference in gray-white matter volume ratio with OHE having a higher ratio than YHE. Subjects with AD did not differ from YHE or OHE in this ratio. There were significant negative correlations between age and total prefrontal volume and age and prefrontal white matter volume in the healthy subjects. In the very old, the decline of white matter volume is disproportionately greater than the decline of gray matter volume. In subjects with AD both gray and white matter loss contribute to the decline of prefrontal volume. This is demonstrated by the gray-white matter ratio that does not differ between YHE and subjects with AD. Thus, it is likely that AD is different from accelerated aging.