Intracranial Cavity Volume Research Articles

Fetal MRI detects early alterations of brain development in Tetralogy of Fallot

Prenatal imaging has identified alterations of brain growth in fetuses with congenital heart disease. However, little is known about the timing of altered brain development and its occurrence in specific congenital heart disease subgroups. This magnetic resonance imaging study aimed to identify early (median, 25 gestational weeks [GW]) changes in fetal total brain (TBV), gray matter (GMV), and subcortical brain (SBV) volumes in Tetralogy of Fallot (TOF) cases in utero. Fetal magnetic resonance imaging (1.5 Tesla) was performed in 24 fetuses who were diagnosed with TOF and 24 normal age-matched control fetuses (20-34 GW). TBV, GMV, SBV, intracranial cavity, cerebellar, ventricular, and external cerebrospinal fluid volumes were quantified by manual segmentation based on coronal T2-weighted sequences. Mixed model analyses of variance and t-tests were conducted to compare cases and control fetuses. TBV was significantly lower (P < .001) in early (<25 GW) and late TOF cases. Both GMV (P = .003) and SBV (P = .001) were affected. The GMV-to-SBV ratio declined in fetuses with TOF (P = .026). Compared with normal fetuses, ventricular volume was increased (P = .0048). External cerebrospinal fluid was enlarged in relation to head size (P < .001). Intracranial cavity volume (P = .314) and cerebellar volume (P = .074) were not significantly reduced in fetuses with TOF. TOF is associated with smaller volumes of gray and white matter and enlarged cerebrospinal fluid spaces. These changes are present at ≤25 GW and indicate altered fetal brain growth in this pathophysiologic entity during early stages of human brain development.

Combined use of MRI and 1H proton magnetic resonance spectroscopy on the detection of brain metabolites and different brain areas of volume in small for gestational age

Objective By 1H magnetic resonance spectroscopy(1H MRS), small for gestational age(SGA)and appropriate for gestational age(AGA) as the detection of brain metabolites and MRI plus software measurement in different brain areas of volume, investigate its cerebral metabolites and the changes of brain in different parts of the volume and significance. Methods Select 88 patients eligible infants, SGA group of 27 cases and AGA group of 21 cases of premature infants; SGA group of 22 cases and AGA group of 18 cases of term infants.Preterm infants with a gestational age of 32 to 36 weeks, term infants with a gestational age of 37 to 41 weeks.Check time between 4 to 7 days old.Calculation of cerebrum volume, cerebellar volume and cerebrospinal fluid volume and intracranial volume, N-acetylaspartic acid(NAA), as 1H MRS area of metabolites measured right frontal choline compounds(Cho)and creatine compounds(Cr)wave, calculation of Cho/Cr and NAA/Cho ratio of NAA/Cr. Results NAA/Cr, the cerebrum volume and intracranial volume of SGA in premature infants group, term infants group and mixed group were 0.627±0.183, (2.831±0.199)×105 mm3, (3.178±0.209)×105 mm3; 0.706±0.139, (3.056±0.217)×105 mm3, (3.411±0.212×105 mm3; 0.708±0.171, (2.932±0.234)×105 mm3, (3.282±0.239)×105 mm3, respectively.NAA/Cr, the cerebrum volume and intracranial volume of AGA in premature infants group, term infants group and mixed group were 0.734±0.101, (2.987±0.111)×105 mm3, (3.347±0.137)×105 mm3; 0.805±0.106, (3.228±0.284)×105 mm3, (3.588±0.306)×105 mm3; 0.721±0.119, (3.098±0.240)×105 mm3, (3.458±0.258)×105 mm3, respectively.The data of SGA group were all lower than those in AGA group, which had significant difference(P 0.05, respectively). In the premature infants groups, the NAA/Cho of SGA group(0.401±0.737) was lower than in the AGA group(0.506±0.116), which had significant difference(P=0.000). In the term infants groups, the NAA/Cho of SGA group(0.483±0.605) was lower than in the AGA group(0.472±0.987), which had no significant difference(P=0.653). In the AGA groups, NAA/Cr, NAA/Cho, cerebellar volume and cerebrospinal fluid volume of premature infants group and term infants group had no significant difference(P>0.05). Both of the cerebellar volume and cerebrospinal fluid volume between the premature infants AGA group and premature infants AGA group had no significant difference(P>0.05). Conclusion Neurons in the brain, the cerebrum volume, the cranial cavity volume and NAA/Cr of SGA was significantly lower than those of AGA, but Cho/Cr, cerebellar volume and cerebrospinal fluid volume of SGA and AGA had no significant difference.NAA/Cr in the brain and the cerebrum volume of SGA may be associated with low volume of small nerve mental retardation, worthy of further study. Key words: Hydrogen proton magnetic resonance spectroscopy; Magnetic resonance imaging; Brain metabolites; Brain volume; Small for gestational age; Appropriate for gestational age

Effects of body size on cranial capacity in Korean youth

Cranial capacity is an important parameter in the fields of evolutionary biology and anthropology and is closely related to brain size. Owing to modern imaging technologies such as computed tomography and magnetic resonance imaging (MRI), the exact measurement of cranial capacity is possible. Our group has reported the effects of body size on brain size in Korean youths based on MRI volumetry. However, the effects of body size on cranial capacity and related analyses have not yet been reported in a Korean population. In this study, we constructed three-dimensional models of the intracranial cavities of young Koreans and calculated the volumes. We evaluated the relations of stature and body weight with cranial capacity and analyzed the correlation of cranial capacity with brain volume. Stepwise linear regression showed that body height is a key parameter contributing to cranial capacity, which is expressed by the following equation: (intracranial capacity, cm3) = (11.440 × body height) – 420.03, R2 = 0.51. The correlation between intracranial cavity volume and brain volume was strong (r = 0.89), which allowed us to calculate an equation for brain volume based on intracranial cavity volume.

Comparison of the endocranial- and brain volumes in brachycephalic dogs, mesaticephalic dogs and Cavalier King Charles spaniels in relation to their body weight.

BackgroundA number of studies have attempted to quantify the relative volumes of the endocranial volume and brain parenchyma in association with the pathogenesis of the Chiari-like malformation (CLM) in the Cavalier King Charles spaniel (CKCS). In our study we examine the influence of allometric scaling of the brain and cranial cavity volume on morphological parameters in different dog breeds. MRI scans of 110 dogs (35 mesaticephalic dogs, 35 brachycephalic dogs, 20 CKCSs with SM, and 20 CKCSs without SM) have been used to create 3-dimensional volumetric models of skull and brain parts. Volumes were related to body weight calculating the adjusted means for different breeds.ResultsThere was a strong global dependency of all volumes to body weight (P < 0.0001). The adjusted means of the absolute and relative volumes of brain parenchyma and cranial compartments are not significantly larger in CKCSs in comparison to brachycephalic and mesaticephalic dogs. A difference in absolute or relative volumes between CKCSs with and without SM after relating these values to body weight could not be identified. The relative volume of the hindbrain parenchyma (caudal fossa parenchyma percentage) was larger in brachycephalic dogs than in CKCSs, without causing herniation or SM.ConclusionAn influence of body weight exist in dogs, which can be sufficiently large to render conclusions on the difference in volumes of the brain and skull unsafe unless some account of the body weight is taken in the analysis. The results of this study challenge the role of overcrowding for the development of SM in dogs.

Nonlocal intracranial cavity extraction.

Automatic and accurate methods to estimate normalized regional brain volumes from MRI data are valuable tools which may help to obtain an objective diagnosis and followup of many neurological diseases. To estimate such regional brain volumes, the intracranial cavity volume (ICV) is often used for normalization. However, the high variability of brain shape and size due to normal intersubject variability, normal changes occurring over the lifespan, and abnormal changes due to disease makes the ICV estimation problem challenging. In this paper, we present a new approach to perform ICV extraction based on the use of a library of prelabeled brain images to capture the large variability of brain shapes. To this end, an improved nonlocal label fusion scheme based on BEaST technique is proposed to increase the accuracy of the ICV estimation. The proposed method is compared with recent state-of-the-art methods and the results demonstrate an improved performance both in terms of accuracy and reproducibility while maintaining a reduced computational burden.

Rapid Buildup of Brain White Matter Hyperintensities Over 4 Years Linked to Ambulatory Blood Pressure, Mobility, Cognition, and Depression in Old Persons

Brain white matter hyperintensities (WMH) are associated with functional decline in older people. We performed a 4-year cohort study examining progression of WMH, its effects on mobility, cognition, and depression with the role of clinic and 24-hour ambulatory systolic blood pressure as a predisposing factor. Ninety-nine subjects, 75-89 years were stratified by age and mobility, with the 67 completing 4-years comprising the cohort. Mobility, cognition, depressive symptoms, and ambulatory blood pressure were assessed, and WMH volumes were determined by quantitative analysis of magnetic resonance images. WMH increased from 0.99±0.98% of intracranial cavity volume at baseline to 1.47±1.2% at 2 years and 1.74±1.30% after 4 years. Baseline WMH was associated with 4-year WMH (p < .0001), explaining 83% of variability. Small, but consistent mobility decrements and some evidence of cognitive decline were noted over 4 years. Regression analyses using baseline and 4-year WMHs were associated with three of five mobility measures, two of four cognitive measures and the depression scale, all performed at 4 years. Increases in ambulatory systolic blood pressure but not clinic systolic blood pressure during the initial 2 years were associated with greater WMH accrual during those years, while ambulatory systolic blood pressure was related to WMH at 4 years. Declines in mobility, cognition, and depressive symptoms were related to WMH accrual over 4 years, and WMH was related to out-of-office blood pressure. This suggests that prevention of microvascular disease, even in asymptomatic older persons, is fundamental for preserving function. There may be value in tighter 24-hour blood pressure control in older persons although this requires further investigation.

Magnetic resonance imaging of the brain and skull of sheep with cerebral coenurosis

To determine MRI characteristics of the skulls and brains of sheep with chronic cerebral coenurosis (CC) caused by naturally acquired Taenia multiceps infection. 33 sheep with CC and 10 healthy control sheep. Sheep underwent MRI of the head. Volumes of the cranial cavity and rostral and caudal fossas of the cranial cavity were determined. For CC-affected sheep, the number, location, and volume of T multiceps cysts were determined and the percentage volumes of cysts in the cranial cavity and rostral and caudal fossas of the cranial cavity were calculated. Focal and diffuse abnormalities of cranial bones in CC-affected sheep were identified. Brain edema and hemorrhage and signs of increased cranial pressure (ICP) in MRI images were determined. Volumes of the cranial cavity and rostral and caudal fossas of the cranial cavity were significantly larger for CC-affected sheep versus healthy control sheep. Total volumes of cysts ranged from 4.40% to 46.93% in cranial cavities of sheep, 4.12% to 51.53% in rostral fossas of cranial cavities of sheep, and 15.24% to 68.30% in caudal fossas of cranial cavities of sheep. Moderate to severe diffuse cranial bone abnormalities and signs of increased ICP in MRI images were detected in 21 and 24 sheep, respectively, and were positively correlated with cyst volumes. Results suggested that cranial cavity volume and morphological abnormalities can be detected in sheep with CC. These changes may reflect abnormalities in ossification of the cranial bones secondary to chronically increased ICP caused by development of T multiceps cysts.

P2‐025: Accurate intracranial cavity volume estimation using multiatlas segmentation

Intracranial cavity volume (ICV) is often used to correct brain structure volumes for inter-individual differences in magnetic resonance imaging (MRI) studies. ICV is frequently used as a correction factor, among other factors such as age, gender or genetics cross-sectional analyses of MRI biomarkers such as hippocampal and brain volumes in Alzheimer's Disease studies. Most existing skull stripping methods extract the brain surface, which can significantly differ from ICV in patients with cerebral atrophy, and is thus unsuitable for volume normalization. In this study, an automated method for accurate ICV extraction and estimation is proposed. Baseline scans of 276 MCI patients from the ADNI database (http://adni.loni.ucla.edu) were analyzed. HCV measurements were performed on three-dimensional T1 sequences. 20 additional MCI patients from the ADNI database were selected as atlases. For each atlas-subject, the ICV was semi-automatically segmented and manually quality-controlled by an experienced rater and used as “gold standard”. The ICV protocol included the area enclosing the brain and CSF, and the contour was delimited by the arachnoid when visible, and the dura mater when not. The atlases and their corresponding ICV labels were propagated to the patient using diffeomorphic demons registration. The 20 propagated ICV labels were then combined using the STAPLE algorithm to get the final patient ICV. The accuracy of the proposed technique was quantitatively compared to our “gold standard” and to the labels obtained with the cross-sectional and longitudinal versions of FreeSurfer (http://surfer.nmr.mgh.harvard.edu/), available on the ADNI database, using the Dice similarity index (“anatomical precision”) and the percent volume difference, D (“volumetric accuracy”), both expressed in percent. Results (mean and SD) are summarized in Table 1. The best Dice and D values were obtained with the proposed technique (98.4%-0.4%) when compared to the cross-sectional (95.0%-0.8%) or longitudinal (93.9%-1.2%) versions of FreeSurfer. A novel ICV quantification method was proposed. The multi-atlas strategy led to significantly better results than a single-atlas approach. The resulting accuracy was higher than cross-sectional and longitudinal implementations of FreeSurfer which appeared to be detecting a “brain envelope,” rather than the ICV, therefore missing a significant portion of external CSF.

Brain Volume and Metabolism in Fetuses With Congenital Heart Disease

Adverse neurodevelopmental outcome is an important source of morbidity in children with congenital heart disease (CHD). A significant proportion of newborns with complex CHD have abnormalities of brain size, structure, or function, which suggests that antenatal factors may contribute to childhood neurodevelopmental morbidity. Brain volume and metabolism were compared prospectively between 55 fetuses with CHD and 50 normal fetuses with the use of 3-dimensinal volumetric magnetic resonance imaging and proton magnetic resonance spectroscopy. Fetal intracranial cavity volume, cerebrospinal fluid volume, and total brain volume were measured by manual segmentation. Proton magnetic resonance spectroscopy was used to measure the cerebral N-acetyl aspartate: choline ratio (NAA:choline) and identify cerebral lactate. Complete fetal echocardiograms were performed. Gestational age at magnetic resonance imaging ranged from 25 1/7 to 37 1/7 weeks (median, 30 weeks). During the third trimester, there were progressive and significant declines in gestational age-adjusted total brain volume and intracranial cavity volume in CHD fetuses relative to controls. NAA:choline increased progressively over the third trimester in normal fetuses, but the rate of rise was significantly slower (P<0.001) in CHD fetuses. On multivariable analysis adjusted for gestational age and weight percentile, cardiac diagnosis and percentage of combined ventricular output through the aortic valve were independently associated with total brain volume. Independent predictors of lower NAA:choline included diagnosis, absence of antegrade aortic arch flow, and evidence of cerebral lactate (P<0.001). Third-trimester fetuses with some forms of CHD have smaller gestational age- and weight-adjusted total brain volumes than normal fetuses and evidence of impaired neuroaxonal development and metabolism. Hemodynamic factors may play an important role in this abnormal development.

MORPHOLOGY OF THE CAUDAL FOSSA IN CAVALIER KING CHARLES SPANIELS

Chiari malformations and syringohydromyelia are an important disease complex in Cavalier King Charles Spaniels. Although abnormalities in caudal fossa morphology are considered major contributors to the development of this disease, limited information exists on the range of morphologies in Cavalier King Charles Spaniels and on the relationship of these to clinically evident disease. Sixty-four Cavalier King Charles Spaniels were studied. Each underwent a neurologic examination and magnetic resonance imaging of the cervical spine and brain. T2-weighted sagittal images were used to determine both the morphologic characteristics and volume of the caudal fossa in each dog. This volume was also analyzed as a percentage of total cranial cavity volume. Each attribute was correlated with neurological grade and presence of syringohydromyelia. Fifteen dogs had neurologic signs, and 59 had morphologic abnormalities of the craniocervical junction. While 27 dogs had syringohydromyelia, 13 of these were clinically normal. Cerebellar herniation and occipital dysplasia were common findings but were not associated with syringohydromyelia. Dorsal compressive lesions were noted at the first and second cervical vertebral junction. Factors associated with the presence of neurologic signs included syringohydromyelia and the ratio of caudal fossa/total cranial cavity volume; dogs with signs had significantly larger syringohydromyelia than asymptomatic dogs. Caudal fossa size was not associated with syringohydromyelia. A positive association was identified between foramen magnum size and length of cerebellar herniation. The prevalence of craniocervical junction abnormalities is high in Cavalier King Charles Spaniels. While several factors are associated with neurologic signs, occipital hypoplasia appears to be the most important factor.

Validation of hippocampal volumes measured using a manual method and two automated methods (FreeSurfer and IBASPM) in chronic major depressive disorder

To validate the usefulness of the packages available for automated hippocampal volumetry, we measured hippocampal volumes using one manual and two recently developed automated volumetric methods. The study included T1-weighted magnetic resonance imaging (MRI) of 21 patients with chronic major depressive disorder (MDD) and 20 normal controls. Using coronal turbo field echo (TFE) MRI with a slice thickness of 1.3 mm, the hippocampal volumes were measured using three methods: manual volumetry, surface-based parcellation using FreeSurfer, and individual atlas-based volumetry using IBASPM. In addition, the intracranial cavity volume (ICV) was measured manually. The absolute left hippocampal volume of the patients with MDD measured using all three methods was significantly smaller than the left hippocampal volume of the normal controls (manual P = 0.029, FreeSurfer P = 0.035, IBASPM P = 0.018). After controlling for the ICV, except for the right hippocampal volume measured using FreeSurfer, both measured hippocampal volumes of the patients with MDD were significantly smaller than the measured hippocampal volumes of the normal controls (right manual P = 0.019, IBASPM P = 0.012; left manual P = 0.003, FreeSurfer P = 0.010, IBASPM P = 0.002),. In the intrarater reliability test, the intraclass correlation coefficients (ICCs) were all excellent (manual right 0.947, left 0.934; FreeSurfer right 1.000, left 1.000; IBASPM right 1.000, left 1.000). In the test of agreement between the volumetric methods, the ICCs were right 0.846 and left 0.848 (manual and FreeSurfer), and right 0.654 and left 0.717 (manual and IBASPM). The automated hippocampal volumetric methods showed good agreement with manual hippocampal volumetry, but the volume measured using FreeSurfer was 35% larger and the agreement was questionable with IBASPM. Although the automated methods could detect hippocampal atrophy in the patients with MDD, the results indicate that manual hippocampal volumetry is still the gold standard, while the automated volumetric methods need to be improved.

Cortical changes in cerebral small vessel diseases: a 3D MRI study of cortical morphology in CADASIL

Brain atrophy represents a key marker of disease progression in cerebrovascular disorders. The 3D changes of cortex morphology occurring during the course of small vessel diseases of the brain (SVDB) remain poorly understood. The objective of this study was to assess the changes affecting depth and surface area of cortical sulci and their clinical and radiological correlates in a cohort of patients with cerebral autosomal dominant arteriolopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a genetic SVDB. Data were obtained from a series of 69 CADASIL patients. Validated methods were used to determine depth and surface area of four cortical sulci. The ratio of brain to intracranial cavity volumes (brain parenchymal fraction--BPF), volume of lacunar lesions (LL) and of white matter hyperintensities, number of cerebral microhaemorrhages, and mean apparent diffusion coefficient were also measured. Association between depth and surface area of the cortical sulci and BPF, clinical status and subcortical MRI lesions were tested. Depth and surface area of cortical sulci obtained in 54 patients were strongly correlated with both cognitive score and disability scales. Depth was related to the extent of subcortical lesions, surface area was related only to age. In additional analyses, the depth of the cingular sulcus was independently associated with the volume of LL (P = 0.001), and that of the superior frontal sulcus with the mean apparent diffusion coefficient (P = 0.003). In CADASIL, important morphological changes of cortical sulci occur in association with clinical worsening, extension of subcortical tissue damage and progression of global cerebral atrophy. These results suggest that the examination of cortical morphology may be of high clinical relevance in SVDB.

Clinical and pathological features in 49 elderly patients with meningiomas

Background As aging in elderly people, their brain tissue has degeneration and brain atrophy of different severity, and the volume of cranial cavity is relatively enlarged, it has greater compensatory ability to the space occupying lesion, and it is difficult to detect the meningioma because it grows to expand slowly, the tumor locates in non-functional region, and there are atypical symptoms and deficiency of localization signs. Objective To investigate the clinicopathologic features of senile meningiomas. Design A retrospective analysis. Setting Affiliated Hospital of Hebei University. Participants Forty-nine elderly patients with meningioma were selected from the Department of Neurosurgery, Affiliated Hospital of Hebei University from May 1999 to March 2005, including 15 males and 34 females, 60–74 years of age, and they were all diagnosed by CT and MRI. Methods The sites of tumors were identified by CT and MRI examinations in all the patients. The tumors were partially or totally resected according to their own conditions. The types of the resected tumor were pathologically observed. The conditions of postoperative recovery were observed after 1, 3 and 6 months, and without new neurological dysfunction or complication was considered as good outcome. Main outcome measures ▪ Sites and pathological types of the tumor; ▪ Postoperative outcomes and complications. Results All the 49 patients were involved in the analysis of results. ▪ The tumors had wide distributions with a main location in brain convexity. Among the 49 cases of meningioma, there were 25 cases of fibrocystic type, 12 cases of meningothelial type, 6 cases of psammomatous type, 4 cases of angiomatous type and 2 cases of microcystic type. ▪ Among the 49 patients, 35 had good outcome, 8 had self-care ability, 4 required care by others, 2 (4.1%) died postoperatively. No long-term complication related to the operation was observed during the follow-up postoperatively. Conclusion Meningioma has a main location in brain convexity, and its pathological type is mainly fibrocystic one, and there is good operative outcome.

Brain Atrophy Is Related to Lacunar Lesions and Tissue Microstructural Changes in CADASIL

Cerebral atrophy has been recently recognized as a key marker of disease progression in cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). The contribution of subcortical cerebral lesions in this process remains undetermined. The aim of this study was to investigate the relationships between cerebral volume and different types of subcortical MRI lesions in CADASIL. Demographic, clinical, and laboratory data from 147 patients with CADASIL recruited from a prospective cohort study were analyzed. Validated methods were used to determine the ratio of brain volume to intracranial cavity volume (brain parenchymal fraction [BPF]), volume of white matter hyperintensities, volume of lacunar lesions, number of cerebral microhemorrhages, and mean apparent diffusion coefficient. Associations between BPF, clinical scales, and the different subcortical MRI markers were tested. BPF obtained in 129 patients was significantly associated with the Mattis dementia rating scale (P<0.0001), Mini-Mental State Examination (P=0.002), and modified Rankin scale (P<0.0001) after adjustment for age and sex. Multiple linear regression modeling showed that BPF was independently associated with mean apparent diffusion coefficient (P<0.0001), volume of lacunar lesions (P=0.004), and age (P<0.0001), accounting for 46% of the observed variance in BPF but not with volume of white matter hyperintensities or number of microhemorrhages. In association with age, mean apparent diffusion coefficient and volume of lacunar lesions are strong and independent MRI predictors of BPF, a key marker of cognitive and motor disability in CADASIL. These results suggest brain atrophy is related to remote and/or diffuse consequences of both lacunar lesions and widespread microstructural alterations within the brain outside lacunar lesions.

Structural brain correlates of alcohol and cannabis use in recreational users.

Previous studies on substance-dependent populations have shown that age of first use and duration of use are associated with alterations in regional brain volumes. However, it is not clear whether such alterations are factors that predispose young people to use, and so are also present in recreational users, or are a consequence of chronic exposure to substances and/or comorbid psychopathology. To investigate relationships between key brain structures and parameters of alcohol and cannabis use, in otherwise healthy male recreational users. High-resolution magnetic resonance imaging was used to measure hippocampal, amygdala, whole-brain and intracranial cavity (ICC) volumes in 22 young men with a history of both alcohol and cannabis use. Linear regression analyses with hippocampal, amygdala and whole-brain volumes as the dependent variables and age and ICC as covariates were performed. Findings showed that use of cannabis and alcohol at an earlier age were independently predictive of larger amygdala volumes, whereas longer duration of cannabis use was predictive of smaller hippocampal volumes. Our findings offer preliminary support for a relationship between patterns of substance use and regional brain volumes in recreational users. It is speculative, but possible that this relationship is an evidence of a neurobiological vulnerability to drug-taking behaviour.

Comparison of Craniometric Features and Cranial Cavity Volume in Domestic Pig (Sus scrofa forma domestica) and Wild Boar (Sus scrofa) in View of Development

Comparison of Craniometric Features and Cranial Cavity Volume in Domestic Pig (<i>Sus scrofa forma domestica</i>) and Wild Boar (<i>Sus scrofa</i>) in View of Development

Accrual of MRI white matter abnormalities in elderly with normal and impaired mobility

White matter signal abnormality (WMSA) is often present in the MRIs of older persons with mobility impairment. We examined the relationship between impaired mobility and the progressive accrual of WMSA. Mobility was assessed with the Short Physical Performance Battery (SPPB) and quantitative measures of gait and balance. Fourteen subjects had baseline and follow-up MRI scans performed 20 months apart. WMSA was detected and quantified using automated computer algorithms. In the control subjects, WMSA volume increased by 0.02±0.05% ICCV (percent intracranial cavity volume)/year while the WMSA of mobility impaired subjects increased five-times faster (0.10±0.10 ICCV/year, p=0.03). WMSA volume was related to some of the mobility measures and was sensitive to change which was not true of the other MRI variables. The study demonstrates the sensitivity of longitudinal automated volumetric analysis of WMSA to differentiate differences in the accrual rate of WMSA in groups selected on the basis of mobility. Based on these results, we propose that a subset of subjects with mobility impairment have accelerated, disease related WMSA accrual, thus explaining the rapid progression of mobility impairment in some older persons without apparent cause. This study demonstrates that quantitative MRI and performance measures can provide valuable insight into the rate of progression and pathophysiologic abnormalities underlying mobility impairment.

Intracranial cavity volume can be accurately estimated from the weights of intracranial contents: confirmation by the dental plaster casting method

Intracranial cavity volume is used to evaluate brain size relative to the intracranial space. This volume can theoretically be obtained from the weights and densities of the brain and surrounding cerebrospinal fluid (weight method). However, the accuracy of this method has not been examined. In this study, we examined the reliability of the weight method, by comparing the intracranial cavity volumes of 41 post-mortem cases obtained by the weight method (ICVw) with those obtained by a dental plaster casting method (ICVcast) which was shown to be unbiased. The ICVw was not significantly different from the ICV cast (P=0.49, paired t-test), and the standard error of difference was 18 ml (1.3% of ICVcast). These results show that the weight method is reliable, and applicable to routine autopsies.

Age‐related brain atrophy with a constant cortical thickness in the normal elderly

A study was performed to determine whether the thickness of the cerebral cortex remains unchanged during agerelated brain atrophy in the normal elderly (physiological brain atrophy of the elderly). Thirty autopsied brains from normal subjects (normal brains; patient age 65–96 years) and two from patients with Alzheimer‐type dementia (ATD brains; patient age 90 and 101 years) were analyzed. Volumes of the fresh brain and intracranial cavity were measured at autopsy to estimate the degree of brain atrophy using the ratio of fresh brain volume to intracranial cavity volume (BV/ICV ratio). Each brain was then fixed, and sliced coronally at 1.0 cm intervals. Each cut surface was photographed, and input to a personal computer. Then, the cross‐sectional areas of the cortex and the white matter, and the perimeter of the cortex were measured to calculate the volumes of the cortex and the white matter. For normal brains, the cortical thickness was constant (0.27 ± 0.01 cm), regardless of age and the BV/ICV ratio. In addition, the volume ratio of the cortex to the white matter remained unchanged, regardless of the brain volume or BV/ICV ratio. These results show that the cortical thickness remains constant regardless of the degree of brain atrophy or cortical atrophy. In the two ATD brains, the cortical thickness was 0.23 and 0.21 cm, being less than that of any of the normal brains. Thus, the mean cortical thickness remains unchanged in physiological brain atrophy of the elderly, and a decrease in cortical thickness can be a pathological phenomenon.

Serial neuropsychological assessment and magnetic resonance imaging analysis in multiple sclerosis.

To assess the correlation between cognitive dysfunction and disease burden in multiple sclerosis (MS) during a 1-year period. The Brief, Repeatable Battery of Neuropsychological Tests in Multiple Sclerosis was performed at entrance and 1 year. Patients underwent at least 20 proton density (range, 20-24) and T2-weighted axial magnetic resonance imaging (MRI) brain scans except for stable patients who were scanned monthly. Magnetic resonance imaging was evaluated using computer-automated, 3-dimensional volumetric analysis. A research clinic of a university hospital. Forty-four patients with MS of the following disease categories: relapsing-remitting (14), relapsing-remitting progressive (12), chronic progressive (13), and stable (5). The relationships between scores on the Brief, Repeatable Battery of Neuropsychological Tests in Multiple Sclerosis and 2 MRI measures (total lesion volume and brain to intracranial cavity volume ratio) were assessed using linear regression. These MRI measures were also compared with cognitive status at 1 year using analysis of variance. Overall, there was no decline in mean cognitive test performance during 1 year. Significant correlations were found between baseline neuropsychological test scores of nonverbal memory, information-processing speed, and attention and both MRI measures. Patients with chronic progressive MS demonstrated the strongest correlations. At 1 year, change in information-processing speed and attention correlated with change in total lesion volume. The mean increase in total lesion volume was 5.7 mL for 4 patients whose cognitive status worsened compared with 0.4 mL for 19 patients who improved and 0.5 mL for 21 patients who remained stable. During a 1-year period mean cognitive performance did not worsen. Automated volumetric MRI measures of total lesion volume and brain to intracranial cavity volume ratio correlated with neuropsychological performance, especially in patients with chronic progressive MS. Worsening MRI lesion burden correlated with cognitive decline.