Extracerebral Cerebrospinal Fluid Research Articles

T1w/FLAIR ratio standardization as a myelin marker in MS patients

IntroductionCalculation of a T1w/T2w ratio was introduced as a proxy for myelin integrity in the brain of multiple sclerosis (MS) patients. Since nowadays 3D FLAIR is commonly used for lesion detection instead of T2w images, we introduce a T1w/FLAIR ratio as an alternative for the T1w/T2w ratio. ObjectivesBias and intensity variation are widely present between different scanners, between subjects and within subjects over time in T1w, T2w and FLAIR images. We present a standardized method for calculating a histogram calibrated T1w/FLAIR ratio to reduce bias and intensity variation in MR sequences from different scanners and at different time-points. Material and methods207 Relapsing Remitting MS patients were scanned on 4 different 3 T scanners with a protocol including 3D T1w, 2D T2w and 3D FLAIR images. After bias correction, T1w/FLAIR ratio maps and T1w/T2w ratio maps were calculated in 4 different ways: without calibration, with linear histogram calibration as described by Ganzetti et al. (2014), and by using 2 methods of non-linear histogram calibration. The first nonlinear calibration uses a template of extra-cerebral tissue and cerebrospinal fluid (CSF) brought from Montreal Neurological Institute (MNI) space to subject space; for the second nonlinear method we used an extra-cerebral tissue and CSF template of our own subjects. Additionally, we segmented several brain structures such as Normal Appearing White Matter (NAWM), Normal Appearing Grey Matter (NAGM), corpus callosum, thalami and MS lesions using Freesurfer and Samseg. ResultsThe coefficient of variation of T1w/FLAIR ratio in NAWM for the no calibrated, linear, and 2 nonlinear calibration methods were respectively 24, 19.1, 9.5, 13.8. The nonlinear methods of calibration showed the best results for calculating the T1w/FLAIR ratio with a smaller dispersion of the data and a smaller overlap of T1w/FLAIR ratio in the different segmented brain structures. T1w/T2w and T1w/FLAIR ratios showed a wider range of values compared to MTR values. ConclusionsCalibration of T1w/T2w and T1w/FLAIR ratio maps is imperative to account for the sources of variation described above. The nonlinear calibration methods showed the best reduction of between-subject and within-subject variability. The T1w/T2w and T1w/FLAIR ratio seem to be more sensitive to smaller changes in tissue integrity than MTR. Future work is needed to determine the exact substrate of T1w/FLAIR ratio and to obtain correlations with clinical outcome.

MRI studies of brain size and growth in individuals with congenital heart disease.

Congenital heart disease (CHD) is the most frequent congenital abnormality. Most infants born with CHD now survive. However, survivors of CHD are at increased risk of neurodevelopmental impairment, which may be due to impaired brain development in the fetal and neonatal period. Magnetic resonance imaging (MRI) provides objective measures of brain volume and growth. Here, we review MRI studies assessing brain volume and growth in individuals with CHD from the fetus to adolescence. Smaller brain volumes compared to healthy controls are evident from around 30 weeks gestation in fetuses with CHD and are accompanied by increased extracerebral cerebrospinal fluid. This impaired brain growth persists after birth and throughout childhood to adolescence. Risk factors for impaired brain growth include reduced cerebral oxygen delivery in utero, longer time to surgery and increased hospital stay. There is increasing evidence that smaller total and regional brain volumes in this group are associated with adverse neurodevelopmental outcome. However, to date, few studies have assessed the association between early measures of cerebral volume and neurodevelopmental outcome in later childhood. Large prospective multicentre studies are required to better characterise the relationship between brain volume and growth, clinical risk factors and subsequent cognitive, motor, and behavioural impairments in this at-risk population.

MRI Natural History of the Leukodystrophy Vanishing White Matter.

Background In vanishing white matter (VWM), a form of leukodystrophy, earlier onset is associated with faster clinical progression. MRI typically shows rarefaction and cystic destruction of the cerebral white matter. Information on the evolution of VWM according to age at onset is lacking. Purpose To determine whether nature and progression of cerebral white matter abnormalities in VWM differ according to age at onset. Materials and Methods Patients with genetically confirmed VWM were stratified into six groups according to age at onset: younger than 1 year, 1 year to younger than 2 years, 2 years to younger than 4 years, 4 years to younger than 8 years, 8 years to younger than 18 years, and 18 years or older. With institutional review board approval, all available MRI scans obtained between 1985 and 2019 were retrospectively analyzed with three methods: (a) ratio of the width of the lateral ventricles over the skull (ventricle-to-skull ratio [VSR]) was measured to estimate brain atrophy; (b) cerebral white matter was visually scored as percentage normal, hyperintense, rarefied, or cystic on fluid-attenuated inversion recovery (FLAIR) images and converted into a white matter decay score; and (c) the intracranial volume was segmented into normal-appearing white and gray matter, abnormal but structurally present (FLAIR-hyperintense) and rarefied or cystic (FLAIR-hypointense) white matter, and ventricular and extracerebral cerebrospinal fluid (CSF). Multilevel regression analyses with patient as a clustering variable were performed to account for the nested data structure. Results A total of 461 examinations in 270 patients (median age, 7 years [interquartile range, 3-18 years]; 144 female patients) were evaluated; 112 patients had undergone serial imaging. Patients with later onset had higher VSR [F(5) = 8.42; P < .001] and CSF volume [F(5) = 21.7; P < .001] and lower white matter decay score [F(5) = 4.68; P < .001] and rarefied or cystic white matter volume [F(5) = 13.3; P < .001]. Rate of progression of white matter decay scores [b = -1.6, t(109) = -3.9; P < .001] and VSRs [b = -0.05, t (109) = -3.7; P < .001] were lower with later onset. Conclusion A radiologic spectrum based on age at onset exists in vanishing white matter. The earlier the onset, the faster and more cystic the white matter decay, whereas with later onset, white matter atrophy and gliosis predominate. © RSNA, 2021.

Magnetic resonance imaging of skull and brain parameters in fetuses with intrauterine growth restriction.

ObjectiveTo compare fetuses with intrauterine growth restriction (IUGR) and those with normal growth, in terms of skull and brain measurements obtained by magnetic resonance imaging (MRI).Materials and MethodsThis was a prospective cohort study including 26 single fetuses (13 with IUGR and 13 with normal growth), evaluated from 26 to 38 weeks of gestation. Using MRI, we measured skull and brain biparietal diameters (BPDs); skull and brain occipitofrontal diameters (OFDs); corpus callosum length and area; transverse cerebellar diameter; extracerebral cerebrospinal fluid (eCSF); and right and left interopercular distances (IODs).ResultsThe following were significantly smaller in IUGR fetuses than in control fetuses: skull BPD (76.9 vs. 78.2 mm; p = 0.0029); brain BPD (67.8 vs. 71.6 mm; p = 0.0064); skull OFD (93.6 vs. 95 mm; p = 0.0010); eCSF (5.5 vs. 8.2 mm; p = 0.0003); right IOD (9.8 vs. 13.9 mm; p = 0.0023); and left IOD (11.8 vs. 16.3 mm; p = 0.0183). The skull BPD/eCSF, brain BPD/eCSF, skull OFD/eCSF, and brain OFD/eCSF ratios were also lower in IUGR fetuses.ConclusionIUGR fetuses had smaller OFD and BPD, both skull and brain, and less eCSF when compared to normal growth fetuses.

Normative linear and volumetric biometric measurements of fetal brain development in magnetic resonance imaging.

To provide normative two-dimensional and three-dimensional measurements of brain development in normal fetuses during the second and third trimester by a new semi-automated method. In this retrospective study, we included 98 normal fetuses at our institution between 21 and 38weeks of gestation. Two-dimensional measurements of the brain were including biparietal diameter, occipitofrontal diameter, head circumference, transverse cerebellar diameter, and atrial diameter. Volumetric parameters were obtained by using ITK-SNAP software, including left and right cerebral hemispheres, lateral ventricle, the cerebellum, and extracerebral cerebrospinal fluid. All linear and volume measurements were positively correlated with gestational age except for cerebrospinal fluid. Each anatomical region of the fetal brain showed a different relative growth rate. There was some volume asymmetry between the left and right lateral ventricles, and the left side was larger. The inter-observer and intra-observer agreement was excellent for all measures. We established the 5th, 50th, and 95th percentile values of fetal brain volume measurements in magnetic resonance, and this may be helpful to understand the damage of fetal brain development.

Automatic brain tissue segmentation in fetal MRI using convolutional neural networks

MR images of fetuses allow clinicians to detect brain abnormalities in an early stage of development. The cornerstone of volumetric and morphologic analysis in fetal MRI is segmentation of the fetal brain into different tissue classes. Manual segmentation is cumbersome and time consuming, hence automatic segmentation could substantially simplify the procedure. However, automatic brain tissue segmentation in these scans is challenging owing to artifacts including intensity inhomogeneity, caused in particular by spontaneous fetal movements during the scan. Unlike methods that estimate the bias field to remove intensity inhomogeneity as a preprocessing step to segmentation, we propose to perform segmentation using a convolutional neural network that exploits images with synthetically introduced intensity inhomogeneity as data augmentation. The method first uses a CNN to extract the intracranial volume. Thereafter, another CNN with the same architecture is employed to segment the extracted volume into seven brain tissue classes: cerebellum, basal ganglia and thalami, ventricular cerebrospinal fluid, white matter, brain stem, cortical gray matter and extracerebral cerebrospinal fluid. To make the method applicable to slices showing intensity inhomogeneity artifacts, the training data was augmented by applying a combination of linear gradients with random offsets and orientations to image slices without artifacts. To evaluate the performance of the method, Dice coefficient (DC) and Mean surface distance (MSD) per tissue class were computed between automatic and manual expert annotations. When the training data was enriched by simulated intensity inhomogeneity artifacts, the average achieved DC over all tissue classes and images increased from 0.77 to 0.88, and MSD decreased from 0.78 mm to 0.37 mm. These results demonstrate that the proposed approach can potentially replace or complement preprocessing steps, such as bias field corrections, and thereby improve the segmentation performance.

Dynamic sodium imaging at ultra-high field reveals progression in a preclinical migraine model.

Under the hypothesis that increased extracellular sodium induces sustained neuronal excitability with the onset and progression of migraine, this study evaluates dynamic in vivo Na fluxes in the brain of a preclinical rodent analogue of migraine. Ultra-high field Na magnetic resonance imaging (MRI) at 21.1 T has demonstrated potential to quantify sodium concentrations with good spatial and temporal resolution after the onset of central sensitization. Sprague-Dawley male rats with implanted intraperitoneal lines were studied by MRI before and after an in situ injection of 10 mg/kg of nitroglycerin (NTG) vs vehicle and saline controls. Slice-selective Na images were acquired using a multislice free induction decay-based chemical shift imaging sequence with resolution of 1.1 × 1.1 × 3 mm for a 9-minute acquisition. A total of 27 repeated scans were acquired over 1 hour of baseline scanning and longitudinally up to 3 hours after injection. Increases of Na MRI signal in the brainstem, extracerebral cerebrospinal fluid, and cisterna magna were evident almost immediately after NTG injection, gaining significance from controls in 36 minutes. The cerebellum and third ventricle also showed sustained trends of increased Na, with the former gaining significance at over 2 hours after NTG injection. The data provide evidence of an early change in sodium concentration, markedly in posterior fossa cerebrospinal fluid and brainstem regions. Further study of fluctuations of sodium concentration and their modulation with treatments could help understand the dynamic features of migraine, locate a putative migraine generator, and guide development of therapeutic measures to correct the disturbance of sodium homeostasis.

Effects of Posthemorrhagic Ventricular Dilatation in the Preterm Infant on Brain Volumes and White Matter Diffusion Variables at Term-Equivalent Age

To evaluate the differential impact of germinal matrix-intraventricular hemorrhage (GMH-IVH) and posthemorrhagic ventricular dilatation (PHVD) on brain and cerebrospinal fluid (CSF) volumes and diffusion variables in preterm born infants at term-equivalent age (TEA). Nineteen infants (gestational age <31weeks) with GMH-IVH grade II-III according to Papile etal and subsequent PHVD requiring intervention were matched against 19 controls with GMH-IVH grade II but no PHVD and 19 controls without GMH-IVH. Outcome variables on magnetic resonance imaging (MRI) including diffusion weighted imaging at TEA were volumes of white matter, cortical gray matter, deep gray matter, brainstem, cerebellum, ventricles, extracerebral CSF, total brain tissue, and intracranial volume (ICV), as well as white matter and cerebellar apparent diffusion coefficients (ADCs). Effects of GMH-IVH and PHVD on TEA-MRI measurements were evaluated using multivariable regression analysis. Brain and CSF volumes were adjusted for ICV to account for differences in bodyweight at TEA-MRI and ICV between cases and controls. PHVD was independently associated with volumes of deep gray matter (β [95% CI]: -1.4cc [-2.3; -.5]), cerebellum (-2.7cc [-3.8; -1.6]), ventricles (+12.7cc [7.9; 17.4]), and extracerebral CSF (-11.2cc [-19.2; -3.3]), and with ADC values in occipital, parieto-occipital, and parietal white matter (β: +.066-.119×10(-3)mm(2)/s) on TEA-MRI (P<.05). No associations were found between GMH-IVH grade II-III and brain and CSF volumes or ADC values at TEA. PHVD was negatively related to deep gray matter and cerebellar volumes and positively to white matter ADC values on TEA-MRI, despite early intervention for PHVD in the majority of the infants. These relationships were not observed for GMH-IVH.

Sequential Cranial Ultrasound and Cerebellar Diffusion Weighted Imaging Contribute to the Early Prognosis of Neurodevelopmental Outcome in Preterm Infants

ObjectiveTo evaluate the contribution of sequential cranial ultrasound (cUS) and term-equivalent age magnetic resonance imaging (TEA-MRI) including diffusion weighted imaging (DWI) to the early prognosis of neurodevelopmental outcome in a cohort of very preterm infants (gestational age [GA] <31 weeks).Study designIn total, 93 preterm infants (median [range] GA in weeks: 28.3 [25.0–30.9]) were enrolled in this prospective cohort study and underwent early and term cUS as well as TEA-MRI including DWI. Early cUS abnormalities were classified as normal, mild, moderate or severe. Term cUS was evaluated for ex-vacuo ventriculomegaly (VM) and enlargement of the extracerebral cerebrospinal fluid (eCSF) space. Abnormalities on T1- and T2-weighted TEA-MRI were scored according to Kidokoro et al. Using DWI at TEA, apparent diffusion coefficients (ADCs) were measured in four white matter regions bilaterally and both cerebellar hemispheres. Neurodevelopmental outcome was assessed at two years’ corrected age (CA) using the Bayley Scales of Infant and Toddler Development, third edition. Linear regression analysis was conducted to explore the correlation between the different neuroimaging modalities and outcome.ResultsModerate/severe abnormalities on early cUS, ex-vacuo VM and enlargement of the eCSF space on term cUS and increased cerebellar ADC values on term DWI were independently associated with worse motor outcome (p<.05). Ex-vacuo VM on term cUS was also related to worse cognitive performance at two years’ CA (p<.01).ConclusionThese data support the clinical value of sequential cUS and recommend repeating cUS at TEA. In particular, assessment of moderate/severe early cUS abnormalities and ex-vacuo VM on term cUS provides important prognostic information. Cerebellar ADC values may further aid in the prognostication of gross motor function.

Cortical Overgrowth in Fetuses With Isolated Ventriculomegaly

Mild cerebral ventricular enlargement is associated with schizophrenia, autism, epilepsy, and attention-deficit/hyperactivity disorder. Fetal ventriculomegaly is the most common central nervous system (CNS) abnormality affecting 1% of fetuses and is associated with cognitive, language, and behavioral impairments in childhood. Neurodevelopmental outcome is partially predictable by the 2-dimensional size of the ventricles in the absence of other abnormalities. We hypothesized that isolated fetal ventriculomegaly is a marker of altered brain development characterized by relative overgrowth and aimed to quantify brain growth using volumetric magnetic resonance imaging (MRI) in fetuses with isolated ventriculomegaly. Fetal brain MRI (1.5 T) was performed in 60 normal fetuses and 65 with isolated ventriculomegaly, across a gestational age range of 22-38 weeks. Volumetric analysis of the ventricles and supratentorial brain structures was performed on 3-dimensional reconstructed datasets. Fetuses with isolated ventriculomegaly had increased brain parenchyma volumes when compared with the control cohort (9.6%, P < 0.0001) with enlargement restricted to the cortical gray matter (17.2%, P = 0.002). The extracerebral cerebrospinal fluid and third and fourth ventricles were also enlarged. White matter, basal ganglia, and thalamic volumes were not significantly different between cohorts. The presence of relative cortical overgrowth in fetuses with ventriculomegaly may represent the neurobiological substrate for cognitive, language, and behavioral deficits in these children.

Cerebral and extracerebral cholesterol metabolism and CSF markers of Alzheimer's disease

The disturbances of the cholesterol synthesis and metabolism described in Alzheimer's disease (AD) may be both a consequence of the neurodegenerative process and a contributor to the pathogenesis. These putative relationships and their underlying mechanisms are not well understood.The aim of this study was to evaluate the relationship between the cerebral and extracerebral cholesterol synthesis and metabolism, and the AD pathology as reflected by CSF markers in humans.We evaluated the relationships between the plasma and the cerebrospinal fluid (CSF) concentrations of cholesterol, the cholesterol precursors lanosterol, lathosterol and desmosterol, and the cholesterol elimination products 24S-hydroxycholesterol and 27-hydroxycholesterol, and the CSF markers for AD pathology Aβ1–42 and p-tau181 in 86 subjects with normal cognition and in 107 AD patients. CSF desmosterol, cholesterol and 24S-hydroxycholesterol in the AD group, and CSF 24S-hydroxycholesterol in the control group correlated with the p-tau181 levels. Neither CSF nor plasma concentrations of the included compounds correlated with the CSF Aβ1–42 levels. In multivariate regression tests including age, gender, albumin ratio, number of the APOEɛ4 alleles, and diagnosis, p-tau181 levels independently predicted the CSF desmosterol, cholesterol and 24S-hydroxycholesterol concentrations. The associations remained significant for CSF cholesterol and 24S-hydroxycholesterol when analyses were separately performed in the AD group.The results suggest that alterations of CNS cholesterol de novo genesis and metabolism are related to neurodegeneration and in particular to the cerebral accumulation of phosphorylated tau.

Spontaneous acute subdural hematoma contralateral to an arachnoid cyst

Arachnoid cysts (AC) are extra-cerebral cerebrospinal fluid collections of unknown origin. They correspond to 1% of all intracranial nontraumatic space-occupying lesions and appear more frequently in the middle fossa (50%). More than 25% of these cysts are incidental findings and the majority of patients are asymptomatic. Seizures, intracranial hypertension signs, neurological deficits, macrocrania, developmental delay and bulging of the skull are the main signs and symptoms of the lesion. AC rupture and bleeding are rare, usually occurring in young adults and associated with trauma. The risk of hemorrhage does not exceed 0.04% / year. We describe the case of a ten-year-old boy who presented with acute signs of intracranial hypertension secondary to a spontaneous acute subdural hematoma, contralateral to an AC of the middle fossa. Three factors were significant in this case: signs and symptoms occurred spontaneously; the presence of an acute subdural hematoma exclusively contralateral to the AC; successful outcome of the conservative treatment.

Positional skull deformities in children: skull deformation without synostosis

Patients with craniosynostosis are readily diagnosed by clinical and neuroimaging findings. Surgical treatment is indicated for preventing neurological deficits and for correcting esthetically unacceptable head deformities. In recent years, we have witnessed a progressive number of neurosurgical consultations for abnormal head shapes unrelated to premature fusion of the cranial sutures, especially of positional plagiocephaly. There have been descriptions of abnormalities in the cerebrospinal fluid (CSF) spaces in children with craniosynostosis. The aim of the present study was to investigate the role of the changes of the CSF spaces in the development of positional skull deformities in children. The authors reviewed demographic, clinical, and neuroimaging data of 23 patients assessed for some form of nonsynostotic skull deformity (group A). The results were compared with those of a simultaneous group of nine infants diagnosed with benign extracerebral collections of fluid (group B). The study group was composed of 11 boys and 12 girls, aged 3 years or younger. Seventeen children had plagiocephaly, four scaphocephaly, and two brachycephaly. Sixteen children (15 with plagiocephaly and 1 with brachycephaly) exhibited enlarged subarachnoid CSF spaces. In group B, the boy/girl ratio was of 7:2. Infants in group A presented at an older age (mean 12.7 months) than group B (mean age at presentation of 7.17 months). Children with benign extracerebral fluid collections were born with a head circumference (HC) greater than infants with positional skull deformities (p=0.005). The percentile of the children's HC at consultation was also larger for children of group B (p=0.03). The form of clinical presentation differed between the two groups. Most infants of group A were seen because of a type of head deformity, and children in group B were studied for macrocephaly. Long-term follow-up assessment showed better outcomes for patients in group B than for children of group A in regard to regression of initial symptoms (p=0.03). Most positional head deformities appear to be related with the children's positioning for sleeping. We have not confirmed macrocephaly as a contributing factor for positional deformities. The distribution of extracerebral CSF and the presence of abnormal collections of fluid in children with positional head deformities do not seem to be related with the findings of pericerebral CSF encountered in children with benign extracerebral collections of fluid. In our view, brain pulsations, transmitted to these accumulations of CSF, play an important part in the development of the infants' skull deformities (p=0.02). The findings of enlarged CSF spaces in children with nonsynostotic skull deformation constituted an age-related event, as these collections tended to disappear as the children grew older (p=0.04).

External hydrocephalus: a probable cause for subdural hematoma in infancy

Subdural hemorrhage is common in infancy, particularly in the first year of life. The most common cause is nonaccidental (child abuse), with accidental in second place. We present three healthy infants, ages 4, 5, and 7 months that, during an evaluation for macrocephaly, were found to have frontal subdural hematoma in association with prominent extracerebral cerebrospinal fluid spaces (external hydrocephalus). There was no history of trauma or risk factors for child abuse. Skull surveys and ophthalmologic examinations were normal. All infants were neurologically intact and achieved normal developmental milestones in one-year follow-up. We suggest that some infants with external hydrocephalus may be at risk for development of subdural hematoma with minimal or no trauma, most likely secondary to stretching of the bridging veins in the unusually widened subarachnoid spaces. Child abuse, although it should always be kept in mind and should be excluded, may not be the most common cause in this specific context. Ravid S, Maytal J. External hydrocephalus: A probable cause for subdural hematoma in infancy.

Cerebrospinal fluid dynamics and relation with blood flow: a magnetic resonance study with semiautomated cerebrospinal fluid segmentation.

To investigate and measure temporal and amplitude aspects of blood and cerebrospinal fluid (CSF) flow waveform relations. A cine phase-contrast magnetic resonance imaging pulse sequence was used to measure blood and CSF flow in 16 healthy subjects aged 27 +/- 4 years. A semiautomated segmentation algorithm was developed to study CSF flow. Standard deviations of the aqueductal and cervical flow measurements carried out by five observers were 1% and 4%, respectively. The peak systolic arterial flow was 1087 +/- 169 mL/min, and the peak cervical CSF flush (173 +/- 59 mL/min) occurred at 5% +/- 3% of the cardiac cycle after the internal carotid systolic peak flow. Peak aqueductal flush flow (13 +/- 5 mL/min) occurred at 21% +/- 7% of the cardiac cycle after the internal carotid systolic peak flow. The CSF segmentation algorithm is reproducible. Brain expansion was quickly regulated by a major extracerebral CSF flush flow, whereas ventricular CSF made only a very small contribution.

Arachnoid membrane closure: Prevention of postoperative cerebrospinal fluid leakage

BACKGROUND Opening the arachnoid membrane causes leakage of the cerebrospinal fluid (CSF). CSF spillage and collection in the subdural, epidural, and/or subcutaneous space are occasionally seen on a postoperative CT scan. Closure of the arachnoid membrane is considered to be unnecessary because most of the fluid in the extracerebral space is temporary and disappears spontaneously. However, in some cases, this CSF collection results in serious complications such as brain compression, extracerebral hematoma, intractable meningitis, and skin problems. In this study for prevention of CSF leakage, the arachnoid membrane was tightly closed with 10-0 nylon after a small opening was made for cerebrovascular bypass surgery. METHODS The arachnoid membrane closure was performed in 18 patients (20 sides) after bypass surgery between 1994 and 1995. As a control, 51 patients (57 sides) had conventional bypass surgery without the arachnoid membrane closure. RESULTS The radiological findings revealed that only one (5%) of the patients had a small fluid collection after arachnoid membrane closure, which was significantly lower than the control (49%). CONCLUSION Arachnoid membrane closure is a simple technique and is effective for prevention of postoperative extracerebral CSF collection.

Brain atrophy in normal ageing and Alzheimer's disease. Volumetric discrimination and clinical correlations.

We examined the differences in volume of the ventricular and extracerebral cerebrospinal fluid spaces in normal ageing and in probable Alzheimer's disease (AD) and we tried to investigate the effects of the severity of illness on the morphometric differentiation of AD and ageing, the principal components underlying brain atrophy in both conditions, and the correlations of these measurements with clinical findings. Forty patients with probable AD were matched with 40 non-demented elderly controls. Both groups underwent standardised clinical tests and unenhanced cranial computed tomography for post hoc volumetric analysis. The lateral and third ventricles and the anterior and lateral fissures were significantly larger in AD than in normal ageing. The volumes of the lateral ventricle and lateral fissure permitted a highly efficient differentiation between normal ageing and AD even at the mild stage of dementia, and this differentiation was improved further in the more severe stages of illness. We identified one principal component underlying brain atrophy in normal ageing and two components in AD: a 'grey matter' component accounting for sulcal and third ventricular enlargement, and a 'white matter' component for lateral ventricular enlargement. In AD, most of the volumetric measurements were significantly correlated with cognitive impairment, but in the group of non-demented elderly controls they were correlated with age. CONCLUSION. Volumetric indices of brain atrophy permit a highly efficient differentiation between normal ageing and AD even in the mild stages of illness and this demonstrates that substantial structural brain changes have developed in the preclinical phase of illness. We suggest that there is an uncoupling between lateral ventricular enlargement and cortical brain atrophy in AD.

Quantitative Magnetic Resonance Imaging Volumetry Distinguishes Delusional Disorder from Late-Onset Schizophrenia

Late paraphrenia is recognised as a heterogeneous disorder. This is reflected by the division of such patients into schizophrenia and delusional disorder in ICD-10. Earlier imaging studies have suggested that major structural abnormalities may be associated with the onset of psychosis in later life. Fifty late paraphrenics and 35 age-matched healthy controls underwent structural magnetic resonance imaging of the whole brain in the coronal plane. Measurements were made of intracranial and brain volumes and the volumes of the intracerebral and extracerebral cerebrospinal fluid spaces. No differences in intracranial, brain or extracerebral cerebrospinal fluid volumes between patients and controls were found. Late paraphrenic patients had greater lateral and third ventricle volumes than controls and the left lateral ventricle was larger than the right. When the patients were divided into appropriate ICD-10 diagnoses: paranoid schizophrenia (n = 31) and delusional disorder (n = 16), lateral ventricle volumes in the delusional disorder patients were much greater than those of the schizophrenics and almost twice those of controls. Structural brain differences underly diagnostic heterogeneity within late paraphrenia. The brains of late onset schizophrenics are only subtly different from those of healthy elderly individuals.

Cranial imaging in autosomal recessive osteopetrosis. Part II. Skull base and brain.

The authors reviewed cranial imaging studies (radiographs, computed tomographic scans, and magnetic resonance [MR] images) in 13 infants and children with the autosomal recessive form of osteopetrosis to characterize patterns of skull base, brain, and cranial nerve involvement at presentation and with progression of disease. Marked sclerosis and deposition of osteopetrotic bone was noted along the anterior (but not posterior) occipitomastoid suture (n = 8), at the basioccipital-exoccipital synchondrosis (n = 9), and along the sphenooccipital synchondrosis (n = 8). Endobones, presumably representing unresorbed primitive ossification centers, were seen in the sphenoidal body and basioccipital bone in 11 of the 13 patients. Marked cupping at the basioccipital-exoccipital synchondrosis was observed in three. Neurologic deficits included blindness (n = 11), conductive hearing loss (n = 11), and facial nerve palsies (n = 4). Delayed myelination was seen with MR imaging in two of five retarded infants, including one with a documented coexisting neuronal storage defect. Prominent extracerebral cerebrospinal fluid spaces were present over the frontal lobes in five of the eight developmentally normal patients, representing either subclinical parenchymal disease or a phenomenon related to discordant growth rates between skull and brain.

Post-traumatic normal pressure hydrocephalus following severe head injury. Result of shunt operation

Six cases of normal perssure hydrocephalus (NPH) were found among 160 surgical cases of intracranial hematoma due to severe head injury, in the past 10 years. Out of the 160 cases, 80 were followed up. The incidence of post-traumatic NPH was 3.7%, or 7.5% in the followed-up cases. After a little improvement following the removal of intracranial hematoma, these cases showed prolonged disturbance of consciousness or a delayed recovery rate and a progressive enlargement of the ventricle without cerebral atrophy on CT scan. Diagnosis of post-traumatic NPH was made by the plateau level of clinical improvement accompanied by absence of intracranial hypertension and a progressive ventricular dilatation shown by an increased bicaudate cerebroventricular index on CT scan. Radioisotope serum albumin cisternography revealed disturbance of cerebrospinal fluid (CSF) circulation in all these cases and was a reliable tool for determining the indication for a shunting operation, which brought a marked improvement in five patients. The authors believe that the shunting operation should be tried on post-traumatic NPH patients who do not show cerebral atrophy. Presence of a subarachnoidal and a contusional hemorrhage on brain surfaces, noted in the operation, suggests the need to pay attention not only to the disturbance of the conventional extracerebral CSF pathway, but to that of the intracerebral pathway as regards the pathogenesis of post-traumatic NPH.