Primary Multiparametric Quantitative Brain MRI: State-of-the-Art Relaxometric and Proton Density Mapping Techniques.

This review on brain multiparametric quantitative MRI (MP-qMRI) focuses on the primary subset of quantitative MRI (qMRI) parameters that represent the mobile ("free") and bound ("motion-restricted") proton pools. Such primary parameters are the proton densities, relaxation times, and magnetization transfer parameters. Diffusion qMRI is also included because of its wide implementation in complete clinical MP-qMRI application. MP-qMRI advances were reviewed over the past 2 decades, with substantial progress observed toward accelerating image acquisition and increasing mapping accuracy. Areas that need further investigation and refinement are identified as follows: (a) the biologic underpinnings of qMRI parameter values and their changes with age and/or disease and (b) the theoretical limitations implicitly built into most qMRI mapping algorithms that do not distinguish between the different spatial scales of voxels versus spin packets, the central physical object of the Bloch theory. With rapidly improving image processing techniques and continuous advances in computer hardware, MP-qMRI has the potential for implementation in a wide range of clinical applications. Currently, three emerging MP-qMRI applications are synthetic MRI, macrostructural qMRI, and microstructural tissue modeling.

Neonatal Cranial Ultrasound Findings among Infants Born Extremely Preterm: Associations with Neurodevelopmental Outcomes at 10 Years of Age.

OBJECTIVE: To examine the association between neonatal cranial ultrasound (CUS) abnormalities among infants born extremely preterm and neurodevelopmental outcomes at 10 years of age. STUDY DESIGN: In a multicenter birth cohort of infants born at <28 weeks of gestation, 889 of 1198 survivors were evaluated for neurologic, cognitive, and behavioral outcomes at 10 years of age. Sonographic markers of white matter damage (WMD) included echolucencies in the brain parenchyma and moderate to severe ventricular enlargement. Neonatal CUS findings were classified as intraventricular hemorrhage (IVH) without WMD, IVH with WMD, WMD without IVH, and neither IVH nor WMD. RESULTS: WMD without IVH was associated with an increased risk of cognitive impairment (OR 3.5, 95% CI 1.7, 7.4), cerebral palsy (OR 14.3, 95% CI 6.5, 31.5), and epilepsy (OR 6.9; 95% CI 2.9, 16.8). Similar associations were found for WMD accompanied by IVH. Isolated IVH was not significantly associated these outcomes. CONCLUSIONS: Among children born extremely preterm, CUS abnormalities, particularly those indicative of WMD, are predictive of neurodevelopmental impairments at 10 years of age. The strongest associations were found with cerebral palsy.

Association of Circulating Proinflammatory and Anti-inflammatory Protein Biomarkers in Extremely Preterm Born Children with Subsequent Brain Magnetic Resonance Imaging Volumes and Cognitive Function at Age 10 Years.

OBJECTIVES: To examine elevated neonatal inflammatory and neurotrophic proteins from children born extremely preterm in relation to later childhood brain Magnetic Resonance Imaging volumes and cognition. STUDY DESIGN: We measured circulating inflammation-related proteins and neurotrophic proteins on postnatal days 1, 7, and 14 in 166 children at 10 years of age (73 males; 93 females). Top quartile levels on ≥2 days for ≥3 inflammation-related proteins and for ≥4 neurotrophic proteins defined exposure. We examined associations among protein levels, brain Magnetic Resonance Imaging volumes, and cognition with multiple linear and logistic regressions. RESULTS: Analyses were adjusted for gestational age at birth and sex. Children with ≥3 elevated inflammation-related proteins had smaller grey matter, brain stem/cerebellar, and total brain volumes than those without elevated inflammation-related proteins, adjusted for neurotrophic proteins. When adjusted for inflammation-related proteins, children with ≥4 neurotrophic proteins, compared with children with no neurotrophic proteins, had larger grey matter and total brain volumes. Higher grey matter, white matter, and cerebellum and brainstem volumes were significantly correlated with higher IQ. Grey and white matter volumes were correlated with each other (r = -0.18; P = .021), and cerebellum and brainstem was highly correlated with grey matter (r = 0.55; P < .001) and white matter (r = 0.29; P < .001). Adjusting for other brain compartments, cerebellum and brainstem was associated with IQ (P = .016), but the association with white matter was marginally significant (P = .051). Grey matter was not associated with IQ. After adjusting for brain volumes, elevated inflammation-related proteins remained significantly associated with a lower IQ, and elevated neurotrophic proteins remained associated with a higher IQ. CONCLUSIONS: Newborn inflammatory and neurotrophin protein levels are associated with later brain volumes and cognition, but their effects on cognition are not entirely explained by altered brain volumes.

Among Children Born Extremely Preterm a Higher Level of Circulating Neurotrophins Is Associated with Lower Risk of Cognitive Impairment at School Age.

OBJECTIVES: To test the hypothesis that higher blood levels of neurotrophic proteins (proteins that support neuronal survival and function) in the first 2 weeks of life are associated with a lower risk of cognitive impairment at 10 years. STUDY DESIGN: We evaluated 812 10-year-old children with neonatal blood specimens enrolled in the multicenter prospective Extremely Low Gestational Age Newborn Study, assessing 22 blood proteins collected on 3 days over the first 2 weeks of life. Using latent profile analysis, we derived a cognitive function level based on standardized cognitive and executive function tests. We defined high exposure as the top quartile neurotrophic protein blood level on ≥2 days either for ≥4 proteins or for a specific cluster of neurotrophic proteins (defined by latent class analysis). Multinomial logistic regression analyzed associations between high exposures and cognitive impairment. RESULTS: Controlling for the effects of inflammatory proteins, persistently elevated blood levels of ≥4 neurotrophic proteins were associated with reduced risk of moderate (OR, 0.35; 95% CI, 0.18-0.67) and severe cognitive impairment (OR, 0.22; 95% CI, 0.09-0.53). Children with a cluster of elevated proteins including angiopoietin 1, brain-derived neurotrophic factor, and regulated upon activation, normal T-cell expressed, and secreted had a reduced risk of adverse cognitive outcomes (OR range, 0.31-0.6). The risk for moderate to severe cognitive impairment was least with 0-1 inflammatory and >4 neurotrophic proteins. CONCLUSIONS: Persisting elevations of circulating neurotrophic proteins during the first 2 weeks of life are associated with lowered risk of impaired cognition at 10 years of age, controlling for increases in inflammatory proteins.

[Prediction of hospital mortality of ST elevation myocardial infarction using TIMI score]. / Validación del puntaje de riesgo TIMI como predictor de mortalidad en pacientes chilenos con infarto agudo al miocardio con supradesnivel de ST.

BACKGROUND: Thrombolysis in myocardial infarction risk score (TIMI-RS) was designed to predict early mortality in patients with a ST elevation acute myocardial infarction (STEAMI). AIM: To evaluate the predictive capacity for hospital mortality of TIMI-RS. MATERIAL AND METHODS: Patients with ≤ 12-hour evolution STEAMI were selected from a prospective registry of all patients hospitalized in our coronary unity within January 1988 and December 2005. Observed mortality was analyzed according to TIMI-RS and its predictive capacity was estimated. RESULTS: We analyzed 1125 consecutive patients aged 61 ± 13 years (76% men). Fifty one percent were smokers, 47% hypertensive and 40% had a history of angina. Fifty eight percent of patients underwent reperfusion therapy. Most patients had TIMI-RS scores ≤ 5 points and only 3.6% had scores ≥ 10 points. Overall mortality was 14.8% and there was an 80% concordance between observed mortality and that predicted with the TIMI-RS score. The area under the curve for the receiver operating characteristic (ROC) curve was 0.7. CONCLUSIONS: TIMI-RS was acceptably useful to predict in-hospital mortality in this group of patients with STEAMI. Differences between the observed and originally predicted mortality are explained by the clinical profile and therapeutic protocols applied to patients in different studies. Thus, caution needs to be taken when interpreting the risk associated to a specific score, particularly within non-reperfused patients whose risk might be underestimated.

Validación del puntaje de riesgo TIMI como predictor de mortalidad en pacientes chilenos con infarto agudo al miocardio con supradesnivel de ST / Prediction of hospital mortality of ST elevation myocardial infarction using TIMI score

Background: Thrombolysis in myocardial infarction risk score (TIMI-RS) was designed to predict early mortality in patients with a ST elevation acute myocardial infarction (STEAMI). Aim: To evaluate the predictive capacity for hospital mortality of TIMI-RS. Material and Methods: Patients with ≤ 12-hour evolution STEAMI were selected from a prospective registry of all patients hospitalized in our coronary unity within January 1988 and December 2005. Observed mortality was analyzed according to TIMI-RS and its predictive capacity was estimated. Results: We analyzed 1125 consecutive patients aged 61 ± 13 years (76% men). Fifty one percent were smokers, 47% hypertensive and 40% had a history of angina. Fifty eight percent of patients underwent reperfusion therapy. Most patients had TIMI-RS scores ≤ 5 points and only 3.6% had scores ≥ 10 points. Overall mortality was 14.8% and there was an 80% concordance between observed mortality and that predicted with the TIMI-RS score. The area under the curve for the receiver operating characteristic (ROC) curve was 0.7. Conclusions: TIMI-RS was acceptably useful to predict in-hospital mortality in this group of patients with STEAMI. Differences between the observed and originally predicted mortality are explained by the clinical profile and therapeutic protocols applied to patients in different studies. Thus, caution needs to be taken when interpreting the risk associated to a specific score, particularly within non-reperfused patients whose risk might be underestimated.

Circulating Inflammatory-Associated Proteins in the First Month of Life and Cognitive Impairment at Age 10 Years in Children Born Extremely Preterm.

OBJECTIVES: To evaluate whether in children born extremely preterm, indicators of sustained systemic inflammation in the first month of life are associated with cognitive impairment at school age. STUDY DESIGN: A total of 873 of 966 eligible children previously enrolled in the multicenter Extremely Low Gestational Age Newborn Study from 2002 to 2004 were evaluated at age 10 years. We analyzed the relationship between elevated blood concentrations of inflammation-associated proteins in the first 2 weeks ("early elevations"; n = 812) and the third and fourth week ("late elevations"; n = 532) of life with neurocognition. RESULTS: Early elevations of C-reactive protein, tumor necrosis factor-α, interleukin (IL)-8, intercellular adhesion molecule (ICAM)-1, and erythropoietin were associated with IQ values >2 SD below the expected mean (ORs: 2.0-2.3) and with moderate to severe cognitive impairment on a composite measure of IQ and executive function (ORs: 2.1-3.6). Additionally, severe cognitive impairment was associated with late protein elevations of C-reactive protein (OR: 4.0; 95% CI 1.5, 10), IL-8 (OR: 5.0; 1.9, 13), ICAM-1 (OR: 6.5; 2.6, 16), vascular endothelial growth factor-receptor 2 (OR: 3.2; 1.2, 8.3), and thyroid-stimulating hormone (OR: 3.1; 1.3, 7.3). Moderate cognitive impairment was most strongly associated with elevations of IL-8, ICAM-1, and vascular endothelial growth factor-receptor 2. When 4 or more inflammatory proteins were elevated early, the risk of having an IQ <70 and having overall impaired cognitive ability was more than doubled (ORs: 2.1-2.4); the presence of 4 or more inflammatory protein elevated late was strongly linked to adverse cognitive outcomes (ORs: 2.9-4.8). CONCLUSIONS: Extremely preterm children who had sustained elevations of inflammation-related proteins in the first postnatal month are more likely than extremely preterm peers without such elevations to have cognitive impairment at 10 years.

Girls and Boys Born before 28 Weeks Gestation: Risks of Cognitive, Behavioral, and Neurologic Outcomes at Age 10 Years.

OBJECTIVES: To compare the prevalence of cognitive, neurologic, and behavioral outcomes at 10 years of age in 428 girls and 446 boys who were born extremely preterm. STUDY DESIGN: A total of 889 of 966 eligible children previously enrolled in the multicenter Extremely Low Gestational Age Newborns Study from 2002-2004 were evaluated at 10 years of age. Children underwent a neuropsychological battery and testing for autism spectrum disorder (ASD), and parents reported on their child's behavior, development, and seizures. RESULTS: Of the children, 28% of boys and 21% of girls exhibited moderate to severe impairment on summary measures of cognitive abilities. Boys had a higher prevalence of impairment than girls in nearly all measures of cognition, were more than twice as likely to have microcephaly (15% in boys, 8% in girls), and require more often assistive devices to ambulate (6% in boys, 4% in girls). In contrast, boys and girls had comparable risk for a history of seizure (identified in 10% of the cohort) or epilepsy (identified in 7% of the cohort). The boy-to-girl ratio of ASD (9% in boys, 5% in girls) was lower than expected compared with the overall US autism population. CONCLUSIONS: In this contemporary cohort of children born extremely premature and evaluated at school age, boys had higher prevalence of cognitive, neurologic, and behavioral deficits than girls. The ratio of boys to girls among those with ASD deserves further study as does the perinatal environmental-genetic interactions that might contribute to male preponderance of deficits in this high-risk sample.