Multidomain intervention for the prevention of cognitive decline after stroke - a pooled patient-level data analysis.

BACKGROUND AND PURPOSE: The aim of this pooled patient-level data analysis was to test if multidomain interventions, addressing several modifiable vascular risk factors simultaneously, are more effective than usual post-stroke care for the prevention of cognitive decline after stroke. METHODS: This pooled patient-level data analysis included two randomized controlled trials using a multidomain approach to target vascular risk factors in stroke patients and cognition as primary outcome. Changes from baseline to 12 months in the trail making test (TMT)-A, TMT-B and 10-words test were analysed using stepwise backward linear mixed models with study as random factor. Two analyses were based on the intention-to-treat (ITT) principle using different imputation approaches and one was based on complete cases. RESULTS: Data from 322 patients (157 assigned to multidomain intervention and 165 to standard care) were analysed. Differences between randomization groups for TMT-A scores were found in one ITT model (P = 0.014) and approached significance in the second ITT model (P = 0.087) and for complete cases (P = 0.091). No significant intervention effects were found for any of the other cognitive variables. CONCLUSION: We found indications that multidomain interventions compared with standard care can improve the scores in TMT-A at 1 year after stroke but not those for TMT-B or the 10-words test. These results have to be interpreted with caution due to the small number of patients.

Whole brain MP2RAGE-based mapping of the longitudinal relaxation time at 9.4T.

Mapping of the longitudinal relaxation time (T1) with high accuracy and precision is central for neuroscientific and clinical research, since it opens up the possibility to obtain accurate brain tissue segmentation and gain myelin-related information. An ideal, quantitative method should enable whole brain coverage within a limited scan time yet allow for detailed sampling with sub-millimeter voxel sizes. The use of ultra-high magnetic fields is well suited for this purpose, however the inhomogeneous transmit field potentially hampers its use. In the present work, we conducted whole brain T1 mapping based on the MP2RAGE sequence at 9.4T and explored potential pitfalls for automated tissue classification compared with 3T. Data accuracy and T2-dependent variation of the adiabatic inversion efficiency were investigated by single slice T1 mapping with inversion recovery EPI measurements, quantitative T2 mapping using multi-echo techniques and simulations of the Bloch equations. We found that the prominent spatial variation of the transmit field at 9.4T (yielding flip angles between 20% and 180% of nominal values) profoundly affected the result of image segmentation and T1 mapping. These effects could be mitigated by correcting for both flip angle and inversion efficiency deviations. Based on the corrected T1 maps, new, 'flattened', MP2RAGE contrast images were generated, that were no longer affected by variations of the transmit field. Unlike the uncorrected MP2RAGE contrast images acquired at 9.4T, these flattened images yielded image segmentations comparable to 3T, making bias-field correction prior to image segmentation and tissue classification unnecessary. In terms of the T1 estimates at high field, the proposed correction methods resulted in an improved precision, with test-retest variability below 1% and a coefficient-of-variation across 25 subjects below 3%.

Non-infectious risk factors for different types of cerebral palsy in term-born babies: a population-based, case-control study.

OBJECTIVE: To identify non-infectious antenatal and perinatal risk factors for cerebral palsy (CP) and its subtypes in children born at term. DESIGN: A population-based, case-control study. SETTING: The western healthcare region of Sweden. POPULATION: A population-based series of children with CP born at term during 1983-94 (n=309) was matched with a control group (n=618). METHODS: A total of 62 variables, maternal characteristics, and prepartal, intrapartal and postpartal variables were retrieved from obstetric records. Both univariate and multivariate analyses were performed for spastic and dyskinetic CP, and for the total CP group. MAIN OUTCOME MEASURES: Cerebral palsy (CP) and subtypes. RESULTS: Univariate analysis resulted in 26 significant risk factors for CP. Birthweight (OR 0.54, 95% CI 0.39-0.74), not living with the baby's father (OR 2.58, 95% CI 1.11-5.97), admittance to a neonatal intensive care unit (NICU) (OR 4.43, 95% CI 3.03-6.47), maternal weight at 34 weeks of gestation (OR 1.02, 95% CI 1.00-1.03) and neonatal encephalopathy (OR 69.2, 95% CI 9.36-511.89) were found to be risk factors for CP in the total CP group in our multivariate analysis. Factors during the periods before, during and after delivery were all shown to increase the risk of spastic diplegia and tetraplegia, whereas mostly factors during the period before delivery increased the risk of spastic hemiplegia, and only factors during delivery increased the risk of dyskinetic CP. Admittance to an NICU was a risk factor for all CP subtypes. CONCLUSIONS: The risk factor pattern differed by CP subtype. The presented risk factors may be useful indicators for identifying children at risk of developing CP, and helpful for targeting individuals for early intervention programmes.

The changing panorama of cerebral palsy in Sweden. X. Prevalence and origin in the birth-year period 1999-2002.

AIM: The aim of the study was to describe the prevalence and origin of cerebral palsy (CP), which is the tenth report from the western Swedish study. METHODS: A population-based study covering 85,737 live births in the area in 1999-2002. Birth characteristics and neuroimaging findings were recorded, prevalence of CP was calculated and aetiology was analysed. RESULTS: CP was found in 186 children. The crude prevalence was 2.18 per 1000 live births. The gestational age-specific prevalence for <28 gestational weeks was 55.6 per 1000 live births, whereas it was 43.7 for 28-31 weeks, 6.1 for 32-36 weeks and 1.43 per 1000 for >36 weeks. There was a female majority among children born at term and a male predominance in children born preterm. Hemiplegia accounted for 38%, diplegia for 32%, tetraplegia for 7%, whereas 17% had dyskinetic CP and 5% ataxia. Neuroimaging showed white-matter lesions in 31% and cortical/subcortical lesions in 29%. The aetiology was considered to be prenatal in 36%, peri/neonatal in 42%, whereas it remained unclassified in 21%. CONCLUSION: The decrease in CP prevalence observed since the 1980s had ceased. An increase in children born at term and in dyskinetic CP was found. In children born before 28 weeks of gestation, the prevalence decreased significantly. White-matter and cortical/subcortical lesions dominated on neuroimaging.

Dyskinetic cerebral palsy in Europe: trends in prevalence and severity.

OBJECTIVE: To describe the trends for and severity of dyskinetic cerebral palsy in a European collaborative study between cerebral palsy registers, the Surveillance of Cerebral Palsy in Europe (SCPE). METHODS: The prevalence of dyskinetic cerebral palsy was calculated in children born in 1976-1996. Walking ability, accompanying impairments and perinatal adverse events were analysed. RESULTS: 578 children had dyskinetic cerebral palsy, of whom 70% were born at term. The prevalence per 1000 live births increased from 0.08 in the 1970s to 0.14 in the 1990s. For the 386 children (70%) with a birth weight of > or =2500 g, the increase was significant (0.05 to 0.12). There was a concurrent decrease in neonatal mortality among children with a birth weight of > or =2500 g. Overall, 16% of the children walked without aids, 24% with aids and 59% needed a wheelchair. Severe learning disability was present in 52%, epilepsy in 51% and severe visual and hearing impairment in 19% and 6%, respectively. Accompanying impairments increased with motor severity. In children born in 1991-1996, perinatal adverse events, that is an Apgar score of <5 at 5 min and convulsions before 72 h, had occurred more frequently compared with children with bilateral spastic cerebral palsy (BSCP, n = 4746). Children with dyskinetic cerebral palsy had more severe cognitive and motor impairments than children with BSCP. CONCLUSIONS: The prevalence of dyskinetic cerebral palsy appears to have increased in children with a normal birth weight. They have frequently experienced perinatal adverse events. Most children have a severe motor impairment and several accompanying impairments.

Quantification of gray matter changes in the cerebral cortex after isolated cerebellar damage: a voxel-based morphometry study.

There is growing evidence based on behavioral and functional imaging studies about the cerebellar involvement in the modulation of cognitive functions. However, it still remains to be clarified how the cerebellum interacts with brain regions sub-serving different cognitive domains. In this study we used magnetic resonance imaging (MRI) and voxel based morphometry (VBM) to investigate changes of cerebral gray matter (GM) density in 15 patients with a focal cerebellar damage (CD) compared to 15 healthy controls. T2-weighted scans and T1-weighted volumes were collected from each subject. With the exception of the cerebellar lesion, none of the patients showed any additional brain MRI abnormality. T1-volumes were analyzed by voxel-based morphometry. Consistent with their neuropsychological abnormalities, patients with right-CD compared to controls showed a reduction of GM density mainly involving the left frontal, parietal and temporal lobes. Conversely, patients with left-CD did not show any significant neuropsychological or cerebral GM abnormality. The present study indicates that specific GM changes may be detected in patients with isolated CD and cognitive dysfunction. We discuss the findings in terms of cerebellar influence on the neuronal networks involved in higher level functions of the association cortex.

Cerebral palsy and restricted growth status at birth: population-based case-control study.

OBJECTIVE: To evaluate the association between growth status at birth and subsequent development of cerebral palsy in preterm and term infants. DESIGN: Population-based case-controlled study. SETTING: Cerebral palsy register in Western Sweden. Subjects Cohort of 334 singletons born between 1983 and 1990, with cerebral palsy diagnosed from age 4, and 668 singletons matched for gestation, gender and delivery unit. METHOD: Growth status at birth was determined using small for gestational age (SGA) categories, with customised birthweight percentiles (SGAcust) based on the Swedish population. MAIN OUTCOME MEASURES: Proportion of babies that were SGAcust, comparing cases and controls in three gestational age categories: early preterm (24-33 weeks), late preterm (34-36 weeks) and term (37+ weeks). RESULTS: Of the 334 children with cerebral palsy, 87 (26.6%) were born early preterm, 27 (8.1%) late preterm and 218 (66%) at term. Children who had been born at term were more likely to have been SGA <1st customised percentile (SGAcust1) than their matched controls (OR 6.6, 95% CI 2.3-18.6). In contrast, children with cerebral palsy born preterm were not more likely to have been SGAcust1 (OR 0.9, 95% CI 0.4-1.9), and this applied to early preterm as well as late preterm births. For less severely small babies (SGA between 1st and 5th customised percentiles), the association with cerebral palsy remained significant for term births (OR 5.2, 95% CI 2.7-10.1) but was again not significant for preterm births. CONCLUSIONS: Term singletons with severely SGA birthweights had a five- to seven-fold risk of developing cerebral palsy compared with gestational age-matched infants with birthweights within normal limits. For children born preterm, SGA was not more likely to be present in cases than in controls. These findings support the concept of cerebral palsy as a multifactorial condition and highlight the importance of antenatal surveillance of fetal growth.

Essential head tremor is associated with cerebellar vermis atrophy: a volumetric and voxel-based morphometry MR imaging study.

BACKGROUND AND PURPOSE: Our aim was to investigate the presence of brain gray matter (GM) abnormalities in patients with different forms of essential tremor (ET). MATERIALS AND METHODS: We used optimized voxel-based morphometry (VBM) and manually traced single region-of-interest analysis in 50 patients with familial ET and in 32 healthy subjects. Thirty patients with ET had tremor of the arms (a-ET), whereas the remaining 20 patients had both arm and head tremor (h-ET). RESULTS: VBM showed marked atrophy of the cerebellar vermis in the patients with h-ET with respect to healthy subjects (P(corrected) < .001). Patients with a-ET showed a trend toward a vermal GM volume loss that did not reach a significant difference with respect to healthy controls (P(uncorrected) < .01). The region-of-interest analysis showed a reduction of the cerebellar volume (CV) in the h-ET group (98.2 +/- 13.6 mm(3)) compared with healthy controls (110.5 +/- 15.5 mm(3), P < .012) as well as in the entire vermal area (790.3 +/- 94.5 mm(2), 898.6 +/- 170.6 mm(2), P < .04 in h-ET and control groups, respectively). CONCLUSIONS: Atrophy of the cerebellar vermis detected in patients with h-ET strongly supports the evidence for the involvement of the cerebellum in the pathophysiology of ET. The lack of a significant CV loss observed in patients with a-ET suggests that a-ET and h-ET might represent distinct subtypes of the same disease.

Realistic simulations of neuronal activity: a contribution to the debate on direct detection of neuronal currents by MRI.

Many efforts have been done in order to preview the properties of the magnetic resonance (MR) signals produced by the neuronal currents using simulations. In this paper, starting with a detailed calculation of the magnetic field produced by the neuronal currents propagating over single hippocampal CA1 pyramidal neurons placed inside a cubic MR voxel of length 1.2 mm, we proceeded on the estimation of the phase and magnitude MR signals. We then extended the results to layers of parallel and synchronous similar neurons and to ensembles of layers, considering different echo times, voxel volumes and neuronal densities. The descriptions of the neurons and of their electrical activity took into account the real neuronal morphologies and the physiology of the neuronal events. Our results concern: (a) the expected time course of the MR signals produced by the neuronal currents in the brain, based on physiological and anatomical properties; (b) the different contributions of post-synaptic potentials and of action potentials to the MR signals; (c) the estimation of the equivalent current dipole and the influence of its orientation with respect to the external magnetic field on the observable MR signal variations; (d) the size of the estimated neuronal current induced phase and magnitude MR signal changes with respect to the echo time, voxel-size and neuronal density. The inclusion of realistic neuronal properties into the simulation introduces new information that can be helpful for the design of MR sequences for the direct detection of neuronal current effects and the testing of bio-electromagnetic models.

Dyskinetic cerebral palsy: a population-based study of children born between 1991 and 1998.

The aim of this study was to describe the epidemiology, aetiology, and clinical findings in dyskinetic cerebral palsy (CP)in a population-based follow-up study of children born between 1991 and 1998. Age range at ascertainment was 4 to 8 years and prevalence was 0.27 per 1000 live-births. Forty-eight children were examined (27 males, 21 females; mean age 9y, range 5-13y). Thirty-nine had dystonic CP and nine a choreo-athetotic subtype. Primitive reflexes were present in 43 children and spasticity in 33. Gross Motor Function Classification System levels were: Level IV, n= 10 and Level V, n= 28. The rate of learning disability (n= 35) and epilepsy (n= 30) increased with the severity of the motor disability. Thirty-eight children had anarthria. Peri- or neonatal adverse events had been present in 34 of 42 children born at >or=34 weeks' gestation. Motor impairment was most severe in this group. Placental abruption or uterine rupture had occurred in 8 participants and 19 of the 42 near-term/term children required assisted ventilation, compared with 1% and 12% respectively in other CP types. Neuroimaging in 39 children born at >or=34 weeks revealed isolated, late third trimester lesions in 24 and a combination of early and late third trimester lesions in seven. Dyskinetic CP is the dominant type of CP found in term-born, appropriate-for-gestational-age children with severe impairments who have frequently experienced adverse perinatal events.

Imaging nervous pathways with MR tractography.

This paper describes the state of the art of tractography, a technique which enables the virtual reconstruction of axon bundles of the central nervous system using diffusion-weighted magnetic resonance images. This technique has raised enthusiasm and expectations among specialists because it is the only non-invasive method for studying the three-dimensional architecture of axonal fibres in vivo. Tractography is a new technique used to assess the anatomy of the central nervous system, and it will be available for routine clinical use in the future. Understanding its potential applications and limitations is therefore important.

Gross and fine motor function and accompanying impairments in cerebral palsy.

The aim of this study was to describe and analyze gross and fine motor function and accompanying neurological impairments in children with cerebral palsy (CP) born between 1991 and 1998 in western Sweden. A population-based study comprised 411 children with a diagnosis of CP ascertained at 4 to 8 years of age. Gross Motor Function Classification System (GMFCS) levels were documented in 367 children (205 males, 162 females). Bimanual Fine Motor Function (BFMF) classification levels of 345 of the children and information on learning disability, epilepsy, visual and hearing impairments, and hydrocephalus from 353 children were obtained. For spastic CP, a new classification according to the Surveillance of Cerebral Palsy in Europe of uni- and bilateral spastic CP was applied. GMFCS was distributed at Level I in 32%, Level II in 29%, Level III in 8%, Level IV in 15%, and Level V in 16%. The corresponding percentages for BFMF were 30.7%, 31.6%, 12.2%, 11.9%, and 13.6% respectively. Learning disability was present in 40%, epilepsy in 33%, and severe visual impairment in 19% of the children. Motor function differed between CP types. More severe GMFCS levels correlated with larger proportions of accompanying impairments and, in children born at term, to the presence of adverse peri/neonatal events in the form of intracranial haemorrhage/stroke, cerebral infection, and hypoxic-ischaemic encephalopathy. GMFCS Level I correlated positively to increasing gestational age. We conclude that the classification of CP should be based on CP type and motor function, as the two combine to produce an indicator of total impairment load.

Disabilities in children with hydrocephalus--a population-based study of children aged between four and twelve years.

BACKGROUND: Children with hydrocephalus represent a heterogeneous group with various aetiologies and disability profiles. Over the years, continuous changes in medical care have occurred and updated information is important. AIM: To study disability profiles in aetiological and gestational age subgroups of children with hydrocephalus in the 1990s. METHOD: A population-based series of 114 children, 70 with infantile hydrocephalus and 44 with hydrocephalus associated with MMC. All the children were examined clinically and interviewed. RESULTS: Learning disabilities were present in 47 % of children with infantile hydrocephalus compared with 16 % of those with MMC, cerebral palsy in 27 % vs. zero and epilepsy in 34 vs. 11 %. Even after excluding children with cerebral palsy, the majority had abnormal tendon reflexes and scored below the 5th centile on a motor test. Hydrocephalus overt at birth, low gestational age, a perinatal origin, enlarged ventricles at follow-up and several shunt revisions all indicated risk factors for a poor outcome. CONCLUSIONS: In spite of major advances in management, hydrocephalus in children still has a considerable impact on outcome. Being born very preterm and with a hydrocephalus that is already overt at birth involve the highest risk of a poor outcome. Apart from major impairments, the children frequently have definite motor problems.

The changing panorama of cerebral palsy in Sweden. IX. Prevalence and origin in the birth-year period 1995-1998.

AIM: This is the ninth report from the western-Swedish study of the prevalence and origin of cerebral palsy. METHODS: A population-based study covering the 88 371 live births in the area in 1995-1998. Birth characteristics, neuroimaging findings and risk factors in children with cerebral palsy were recorded, prevalence was calculated, and aetiology was analysed. RESULTS: The study comprised 170 children with cerebral palsy, i.e. a prevalence of 1.92 per 1000 live births. Excluding eight post-neonatally derived cases, the gestational age-specific prevalences were 77 per 1000 for children born before 28 wk of gestation, 40 for children born at 28-31 wk, 7 for children born at 32-36 wk and 1.1 for children born after 36 wk of gestation. Spastic hemiplegia, diplegia and tetraplegia accounted for 38%, 35% and 6%, respectively, dyskinetic cerebral palsy for 15%, and ataxia for 6%. For the first time, hemiplegia was now most common, due to the decline in preterm diplegia. There was a further increase in full-term dyskinetic cerebral palsy. The origin of cerebral palsy in children born at term was considered to be prenatal in 38%, peri/neonatal in 35% and unclassifiable in 27%, while in children born preterm it was 17%, 49% and 33%, respectively. CONCLUSION: The decreasing trend from the period 1991-1994 continued, both in children born at term and especially in those born preterm. However, the increase in dyskinetic cerebral palsy in children born at term was a matter of concern. In this group, a perinatal hypoxic ischaemic encephalopathy had been present in 71%.

Turbo-Proton Echo Planar Spectroscopic Imaging (t-PEPSI) MR technique in the detection of diffuse axonal damage in brain injury. Comparison with Gradient-Recalled Echo (GRE) sequence.

PURPOSE: Diffuse axonal injury (DAI) is a common type of primary neuronal injury in patients with severe traumatic brain injury, and is frequently accompanied by tissue tear haemorrhage. The T2*-weighted gradient-recalled echo (GRE) sequences are more sensitive than T2-weighted spin-echo images for detection of haemorrhage. This study was undertaken to determine whether turbo-PEPSI, an extremely fast multi-echo-planar-imaging sequence, can be used as an alternative to the GRE sequence for detection of DAI. MATERIALS AND METHODS: Nineteen patients (mean age 24,5 year) with severe traumatic brain injury (TBI), occurred at least 3 months earlier, underwent a brain MRI study on a 1.5-Tesla scanner. A qualitative evaluation of the turbo-PEPSI sequences was performed by identifying the optimal echo time and in-plane resolution. The number and size of DAI lesions, as well as the signal intensity contrast ratio (SI CR), were computed for each set of GRE and turbo-PEPSI images, and divided according to their anatomic location into lobar and/or deep brain. RESULTS: There was no significant difference between GRE and turbo-PEPSI sequences in the total number of DAI lesions detected (283 vs 225 lesions, respectively). The GRE sequence identified a greater number of hypointense lesions in the temporal lobe compared to the t-PEPSI sequence (72 vs 35, p<0.003), while no significant differences were found for the other brain regions. The SI CR was significantly better (i.e. lower) for the turbo-PEPSI than for the GRE sequence (p<0.00001). CONCLUSIONS: Owing to its very short scan time and high sensitivity to the haemorrhage foci, the turbo-PEPSI sequence can be used as an alternative to the GRE to assess brain DAI in severe TBI patients, especially if uncooperative and medically unstable.

Evaluation of mixed effects in event-related fMRI studies: impact of first-level design and filtering.

With the introduction of event-related designs in fMRI, it has become crucial to optimize design efficiency and temporal filtering to detect activations at the 1st level with high sensitivity. We investigate the relevance of these issues for fMRI population studies, that is, 2nd-level analysis, for a set of event-related fMRI (er-fMRI) designs with different 1st-level efficiencies, adopting three distinct 1st-level filtering strategies as implemented in SPM99, SPM2, and FSL3.0. By theory, experiments, and simulations using physiological fMRI noise, we show that both design and filtering impact the outcome of the statistical analysis, not only at the 1st but also at the 2nd level. There are several reasons behind this finding. First, sensitivity is affected by both design and filtering, since the scan-to-scan variance, that is the fixed effect, is not negligible with respect to the between-subject variance, that is the random effect, in er-fMRI population studies. The impact of the fixed effects error on the sensitivity of the mixed effects analysis can be mitigated by an optimal choice of er-fMRI design and filtering. Moreover, the accuracy of the 1st- and 2nd-level parameter estimates also depend on design and filtering; especially, we show that inaccuracies caused by the presence of residual noise autocorrelations can be constrained by designs that have hemodynamic responses with a Gaussian distribution. In conclusion, designs with both good efficiency and decorrelating properties, for example, such as the geometric or Latin square probability distributions, combined with the "whitening" filters of SPM2 and FSL3.0, give the best result, both for 1st- and 2nd-level analysis of er-fMRI studies.

Intermolecular double quantum coherences (iDQc) and diffusion-weighted imaging (DWI) imaging of the human brain at 1.5 T.

To study the sensitivity of intermolecular double quantum coherences (iDQc) imaging contrast to brain microstructure and brain anisotropy, we investigated the iDQC contrast between differently structured areas of the brain according to the strength and the direction of the applied correlation gradient. Thus diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) maps have been obtained. This procedure, which consists of analyzing both iDQc and DWI images at different gradient strength and gradient direction, could be a promising tool for clinical brain investigations performed with higher than 1.5 T magnetic fields.

In vivo multiple spin echoes imaging of trabecular bone on a clinical 1.5 T MR scanner.

In vivo multiple spin echoes (MSE) images of bone marrow in trabecular bone were obtained for the first time on a clinical 1.5 T scanner. Despite of a reduced sensitivity of the MSE trabecular bone images with respect to the cerebral matter ones, it is possible to observe some features in the MSE trabecular bone images that may be useful in the diagnosis of osteopenic states. Two different CRAZED-type MSE imaging sequences based on spin-echo and EPI imaging modalities were applied in phantom and in vivo. Preliminary experimental results indicate that EPI imaging readout seems to conceal the MSE contrast correlated with pore dimension in porous media. However it is still possible to detect anisotropy effects related to the bone structure in MSE-EPI images. Some strategies are suggested to optimize the quality of MSE trabecular bone images.

Real-time quantification of T(2)(*) changes using multiecho planar imaging and numerical methods.

Conventional approaches to quantify whole brain T(2)(*) maps use nonlinear regression with intensive computational requirements that therefore likely limit quantitative T(2)(*) mapping for real-time applications. To overcome these limitations an alternative method, NumART(2)(*) (NUMerical Algorithm for Real-time T(2)(*) mapping) that directly calculates T(2)(*) by a linear combination of images obtained at three or more different echo times was developed. NumART(2)(*), linear least-squares, and nonlinear regression techniques were applied to multiecho planar images of the human brain and to simulated data. Although NumART(2)(*) may overestimate T(2)(*), it yields comparable values to regression techniques in cortical and subcortical areas, with only moderate deviations for echo spacings between 18 and 40 ms. NumART(2)(*), like linear regression, requires 2% of the computational time needed for nonlinear regression and compares favorably with linear regression due to its higher precision. The use of NumART(2)(*) for continuous on-line T(2)(*) mapping in real time fMRI studies is shown.

Cerebral palsy in preterm infants: a population-based case-control study of antenatal and intrapartal risk factors.

UNLABELLED: Previous studies have indicated that foetomaternal infection increases the risk of spastic cerebral palsy (CP) in term infants, whereas this association appears to be less evident in preterm infants. The aim of this study was to analyse infection-related risk factors for spastic CP in preterm infants. A population-based series of preterm infants with spastic CP, 91 very preterm (<32 wk) and 57 moderately preterm (32-36 wk), born in 1983-90, were included and matched with a control group (n = 296). In total, 154 maternal, antenatal and intrapartal variables were retrieved from obstetric records. In the entire group, histological chorioamnionitis/pyelonephritis, long interval between rupture of membranes and birth, admission-delivery interval <4 h and Apgar scores of <7 at 1 min just significantly increased the risk of CP, and Apgar scores of <7 at 5 and 10 min were strongly associated with an increased risk. Abruptio placentae, Apgar scores <7 at 1 min and pathological non-stress test (reason for delivery) were significant risk factors of CP only in the moderately preterm and hemiplegic groups, whereas fever before delivery was a significant risk factor in the very preterm and spastic diplegic groups. Antibiotics during pregnancy was associated with CP only in the spastic diplegic CP group. CONCLUSION: Antenatal infections marginally increased the risk of CP. Low Apgar score and abruptio placentae were associated with CP, especially in moderately preterm infants with hemiplegic CP.