Experimental basis of percutaneous laser disc decompression (PLDD): a review of literature.
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Decompression, Surgical↗
Biomedical subjects
Mark A van Buchem
Publications and source records attributed to Mark A van Buchem.
Shape differences of the brain ventricles in Alzheimer's disease.
The brain ventricles are surrounded by gray and white matter structures that are often affected in dementia in general and Alzheimer's disease (AD) in particular. Any change of volume or shape occurring in these structures must affect the volume and shape of the ventricles. It is well known that ventricular volume is significantly higher in AD patients compared to age-matched healthy subjects. However, the large overlap between the two volume distributions makes the measurement unsuitable as a biomarker of the disease. The purpose of this work was to assess whether local shape differences of the ventricles can be detected when comparing AD patients and controls. In this work, we captured the ventricle's shape and shape variations of 29 AD subjects and 25 age-matched controls, using a fully automatic shape modeling technique. By applying permutation tests on every single node of a mesh representation of the shapes, we identified local areas with significant differences. About 22% of an average surface of the ventricles presented significant difference (P < 0.05) ( approximately 14% of the left against approximately 7% of the right side). We found out that in patients with Alzheimer disease, not only the lateral horns were significantly affected, but also the areas adjacent to the anterior corpus callosum, the splenium of the corpus callosum, the amygdala, the thalamus, the tale of the caudate nuclei (especially the left one), and the head of the left caudate nucleus.
Aged↗
Annular erythema of Sjögren's syndrome.
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Adult↗
Brain stem and cerebellar hyperintense lesions in migraine.
BACKGROUND AND PURPOSE: Migraineurs are at increased risk of cerebellar infarcts and supratentorial white matter lesions. The prevalence, frequency, and distribution of infratentorial hyperintense lesions in migraine are unknown. METHODS: Migraineurs with aura (n=161), without aura (n=134), and controls (n=140) from a population-based sample of adults (30 to 60 years of age) were evaluated with MRI. RESULTS: Infratentorial hyperintensities were identified in 13 of 295 (4.4%) migraineurs and in 1 of 140 (0.7%) controls (P=0.04). Twelve cases had hyperintensities, mostly bilaterally, in the dorsal basis pontis. Those with infratentorial hyperintensities also had supratentorial white matter lesions more often. CONCLUSIONS: We found an increased prevalence of infratentorial (mostly pontine) hyperintensities in migraineurs from the general population. This extends the knowledge about vulnerable brain regions and type of lesions in migraine brains. A hemodynamic ischemic pathogenesis is likely, but further research is needed.
Adult↗
Association between microscopic brain damage as indicated by magnetization transfer imaging and anticardiolipin antibodies in neuropsychiatric lupus.
The pathogenetic role of anticardiolipin antibodies (aCLs) in patients with neuropsychiatric systemic lupus erythematosus (NPSLE) without cerebral infarcts remains elusive. Magnetization transfer imaging (MTI) has proved to be a sensitive tool for detecting diffuse microscopic brain damage in NPSLE patients. In this study we examined the correlation between grey and white matter magnetization transfer ratio (MTR) parameters and the presence of IgM and IgG aCLs and lupus anticoagulant in 18 patients with systemic lupus erythematosus and a history of NPSLE but without cerebral infarcts on conventional magnetic resonance imaging. Lower grey matter mean MTR (P < 0.05), white matter mean MTR (P < 0.05), white matter peak location (P < 0.05) and grey matter peak location (trend toward statistical significance) were observed in IgM aCL-positive patients than in IgM aCL-negative patients. No significant differences were found in MTR histogram parameters with respect to IgG aCL and lupus anticoagulant status, nor with respect to anti-dsDNA or anti-ENA (extractable nuclear antigen) status. This is the first report of an association between the presence of aCLs and cerebral damage in grey and white matter in NPSLE. Our findings suggest that aCLs are associated with diffuse brain involvement in NPSLE patients.
Adult↗
Detection of change in CNS involvement in neuropsychiatric SLE: a magnetization transfer study.
PURPOSE: To assess whether magnetization transfer imaging (MTI) parameters change in correspondence with clinical changes in NPSLE patients. MATERIALS AND METHODS: Nineteen female patients (mean age=37.5 years, range=19-64) underwent MTI on at least two separate occasions (mean time between scans=25.4 months, range=5.4-52.3 months). Twenty-four pairs of scans of 19 patients were available. Each patient's clinical course was classified as improved, stable, or deteriorated. Whole-brain magnetization transfer ratio (MTR) histograms were generated. The peak height of these histograms was used as an estimate of parenchymal integrity. Based on the change in clinical status, paired examinations were grouped and tested for significant differences between the first and second examinations using paired-samples t-tests. RESULTS: Four patients clinically deteriorated, all patients showed a significant peak height decrease (mean decrease=8.6%, P=0.02), and in 14 patients with stable disease the peak height did not change significantly (mean increase=0.4%). Six patients clinically improved, and all showed a significant relative peak height increase (mean increase=12.0%, P=0.02). CONCLUSION: The peak height of whole-brain MTR histograms corresponds to changes in the clinical status of individual NPSLE patients. This suggests that MTI can be a valuable tool in the clinical assessment of such patients.
Adult↗
Magnetic resonance angiography of the human middle meningeal artery: implications for migraine.
PURPOSE: To describe a novel noninvasive method for studying middle meningeal artery (MMA) diameter changes in vivo in humans. Dilatation of the MMA has been implicated in the pathophysiology of migraine headache, but no direct evidence has been obtained in humans. MATERIALS AND METHODS: The diameter of the MMA (the extracranial part) was measured in 19 healthy volunteers before and after administration of a vasodilator (nitroglycerin (NTG), 1.2 mg sublingually) known to provoke headache. We used magnetic resonance angiography (MRA) in combination with a 47-mm microscopy coil and a semiautomatic contour detection program. RESULTS: The diameter of the MMA was 1.5+/-0.26 mm (mean+/-SD) before and 1.79+/-0.30 mm after NTG administration. This increase was 20.1% (95% CI=12.9-27.3; P<0.001). The mean increase in subjects who developed headache (N=11) was 0.34+/-0.19 mm as compared to 0.22 mm+/-0.20 mm in the eight subjects who did not (95% CI for difference=-0.07 to 0.31; P=0.188). CONCLUSION: MRA in combination with a 47-mm microscopy coil is a novel, noninvasive method to measure changes in the diameter of human meningeal vessels, with potential applications for migraine and other fields of neurovascular research.
Adolescent↗
Selective involvement of the amygdala in systemic lupus erythematosus.
BACKGROUND: Antibodies specifically affect the amygdala in a mouse model of systemic lupus erythematosus (SLE). The aim of our study was to investigate whether there is also specific involvement of the amygdala in human SLE. METHODS AND FINDINGS: We analyzed a group of 37 patients with neuropsychiatric SLE (NP-SLE), 21 patients with SLE, and a group of 12 healthy control participants with diffusion weighted imaging (DWI). In addition, in a subset of eight patients, plasma was available to determine their anti-NMDAR antibody status. From the structural magnetic resonance imaging data, the amygdala and the hippocampus were segmented, as well as the white and gray matter, and the apparent diffusion coefficient (ADC) was retrieved. ADC values between controls, patients with SLE, and patients with NP-SLE were tested using analysis of variance with post-hoc Bonferroni correction. No differences were found in the gray or white matter segments. The average ADC in the amygdala of patients with NP-SLE and SLE (940 x 10(-6) mm2/s; p = 0.006 and 949 x 10(-6) mm2/s; p = 0.019, respectively) was lower than in healthy control participants (1152 x 10(-6) mm2/s). Mann-Whitney analysis revealed that the average ADC in the amygdala of patients with anti-NMDAR antibodies (n = 4; 802 x 10(-6) mm2/s) was lower (p = 0.029) than the average ADC of patients without anti-NMDAR antibodies (n = 4; 979 x 10(-6) mm2/s) and also lower (p = 0.001) than in healthy control participants. CONCLUSIONS: This is the first study to our knowledge to observe damage in the amygdala in patients with SLE. Patients with SLE with anti-NMDAR antibodies had more severe damage in the amygdala compared to SLE patients without anti-NMDAR antibodies.
Adult↗
Seasonal variation of primary neuropsychiatric systemic lupus erythematosus.
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Adolescent↗
Whole brain magnetization transfer histogram analysis of pediatric acute lymphoblastic leukemia patients receiving intrathecal methotrexate therapy.
BACKGROUND AND PURPOSE: The purpose of this prospective study was to evaluate the hypothesis that magnetization transfer ratio (MTR) histogram analysis of the whole brain could detect early and subtle brain changes nonapparent on conventional magnetic resonance imaging (MRI) in children with acute lymphoblastic leukemia (ALL) receiving methotrexate (MTX) therapy. MATERIALS AND METHODS: Subjects in this prospective study comprised 10 children with ALL (mean age, 6 years; range, 0-16 years). In addition to conventional MRI, magnetization transfer images were obtained before and after intrathecal and intravenous MTX therapy. MTR values were calculated and plotted as a histogram, and peak height and location were calculated. Differences in peak height and location between pre- and post-MTX therapy scans were statistically analyzed. Conventional MRI was evaluated for abnormal signal area in white matter. RESULTS: MTR peak height was significantly lower on post-MTX therapy scans than on pre-MTX therapy scans (p = 0.002). No significant differences in peak location were identified between pre- and post-chemotherapy imaging. No abnormal signals were noted in white matter on either pre- or post-MTX therapy conventional MRI. CONCLUSIONS: This study demonstrates that MTR histogram analysis allows better detection of early and subtle brain changes in ALL patients who receive MTX therapy than conventional MRI.
Adolescent↗
Late-onset dementia: structural brain damage and total cerebral blood flow.
PURPOSE: To prospectively compare indicators of structural brain damage and total cerebral blood flow in patients with late-onset dementia, subjects of the same age with optimal cognitive function, and young subjects. MATERIALS AND METHODS: The institutional ethics committee approved the studies, and all participants (or their guardians) gave informed consent. The test group included 17 patients older than 75 years (four men, 13 women; median age, 83 years) and with a diagnosis of dementia according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. The control group included 16 subjects (four men, 12 women; median age, 87 years) with optimal cognitive function, who were selected from among 599 elderly subjects enrolled in a population-based follow-up study, and 15 young healthy subjects (seven men, eight women; median age, 29 years). Measurements of intracranial and total brain volumes, structural brain damage, and cerebral blood flow were obtained with magnetic resonance imaging. Mean values were compared with the t test; medians, with the Mann-Whitney U test. RESULTS: Values for total brain volume were significantly smaller in elderly subjects (P < .001) but did not differ significantly between patients with dementia and subjects of the same age with optimal cognitive function (P = .69). Among the elderly, significantly higher scores for number and extent of white matter areas of signal hyperintensity (P = .028) and lower magnetization transfer ratios (P = .016) indicated greater structural brain damage in those with dementia. Cerebral blood flow was 246 mL/min lower (P < .001) in elderly subjects than in young subjects. In patients with dementia, cerebral blood flow was 108 mL/min lower than that in subjects of the same age with optimal cognitive function (551 vs 443 mL/min, P < .001). CONCLUSION: The combined observations of more structural brain damage and lower cerebral blood flow in demented elderly individuals than in subjects of the same age with optimal cognitive function support the hypothesis that vascular factors contribute to dementia in old age.
Aged↗
Infarcts in the posterior circulation territory in migraine. The population-based MRI CAMERA study.
In a previous study, migraine cases from the general population were found to be at significantly increased risk of silent infarct-like lesions in the posterior circulation (PC) territory of the brain, notably in the cerebellum. In this study we describe the clinical and neuroimaging characteristics of migraine cases with and without aura and controls with PC lesions. In total, 39 PC infarct-like lesions represented the majority (65%) of all 60 identified brain infarct-like lesions in the study sample (n = 435 subjects with and without migraine). Most lesions (n = 33) were located in the cerebellum, often multiple, and were round or oval-shaped, with a mean size of 7 mm. The majority (88%) of infratentorial infarct-like lesions had a vascular border zone location in the cerebellum. Prevalence of these border zone lesions differed between controls (0.7%), cases with migraine without aura (2.2%) and cases with migraine with aura (7.5%). Besides higher age, cardiovascular risk factors were not more prevalent in cases with migraine with PC lesions. Presence of these lesions was not associated with supratentorial brain changes, such as white matter lesions. The combination of vascular distribution, deep border zone location, shape, size and imaging characteristics on MRI makes it likely that the lesions have an infarct origin. Previous investigators attributed cases of similar 'very small' cerebellar infarcts in non-migraine patients to a number of different infarct mechanisms. The relevance and likelihood of the aetiological options are placed in the context of known migraine pathophysiology. In addition, the specific involvement of the cerebellum in migraine is discussed. The results suggest that a combination of (possibly migraine attack-related) hypoperfusion and embolism is the likeliest mechanism for PC infarction in migraine, and not atherosclerosis or small-vessel disease.
Adult↗
Neuropsychological correlates of MRI measures in the continuum of cognitive decline at old age.
OBJECTIVE: To investigate the independent associations between medial temporal lobe atrophy and white matter hyperintensities (WMH) and cognitive functions in the elderly. METHODS: Cognitive functions of 41 Alzheimer's disease patients, 20 patients with mild cognitive impairment and 28 elderly subjects without memory complaints were assessed using a neuropsychological test battery. Quantitative MRI measures of medial temporal lobe volume and WMH were obtained. Multiple regression analyses were performed to assess the independent contribution of MRI measures to impairment in several cognitive functions. RESULTS: Scores on the Wechsler Memory Scale and Trails B depended selectively on medial temporal lobe volume, whereas WMH selectively contributed to performance on Trails A. Medial temporal lobe volume and WMH both contributed to scores on the Cambridge Cognitive Examination and the Boston naming task. CONCLUSIONS: MRI measures suggestive of Alzheimer-type pathology and microvascular pathology independently contribute to cognitive decline at old age. Memory impairment as measured using the Wechsler Memory Scale and performance on Trails B primarily depended on medial temporal lobe atrophy. Psychomotor slowness, as measured using Trails A, mainly depended on WMH. These results suggest that vascular pathology and Alzheimer-type pathology each have specific cognitive correlates.
Aged↗
MRI measures and progression of cognitive decline in nondemented elderly attending a memory clinic.
OBJECTIVE: To investigate whether MRI-based volumes of whole brain, medial temporal lobe and white matter hyperintensities (WMH) predict progression of cognitive decline in a sample of nondemented elderly. METHODS: Thirty-seven nondemented elderly attending a memory clinic and 28 elderly controls participated in this follow-up study. The average follow-up period was 1.8 years. Cognitive function was measured at baseline and follow-up with the Cambridge Cognitive Examination (CAMCOG). Baseline Magnetic Resonance Imaging (MRI) provided quantitative measures of whole brain, medial temporal lobe and WMH. Linear mixed models controlled for age and sex were used to assess the independent associations between MRI measures, baseline cognition, and annual decline in cognition. RESULTS: Medial temporal lobe volume was independently associated with baseline CAMCOG score (p < 0.01), whereas whole brain volume (p < 0.01) and WMH (p < 0.05) were associated with annual decline in CAMCOG score. CONCLUSIONS: These data suggest that regional damage to the medial temporal lobes underlies initial mild cognitive impairment, whereas more global brain changes, such as whole brain atrophy and WMH, contribute to further progression of cognitive decline.
Aged↗
Fully automatic shape modelling using growing cell.
In this paper, we present a new framework for shape modelling and analysis: we suggest to look at the problem from a pattern recognition point of view, and claim that under this prospective several advantages are achieved. The modelling of a surface with a point distribution model is seen as an unsupervised clustering problem, and tackled by using growing cell structures. The adaptation of a model to new shapes is studied as a classification task, and provides a straightforward solution to the point correspondence problem in active shape modelling. The method is illustrated and tested in 3D synthetic datasets and applied to the modelling of brain ventricles in an elderly population.
Cerebral Ventricles↗
Lack of effect of pravastatin on cerebral blood flow or parenchymal volume loss in elderly at risk for vascular disease.
BACKGROUND AND PURPOSE: Ageing is associated with a decline in cerebral blood flow. Animal studies have shown that cholesterol-lowering therapy with statins might preserve cerebral blood flow (CBF). We examined the effect of 40 mg pravastatin on the decline in CBF and brain volume in a subset of elderly subjects participating in the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) trial. METHODS: Randomization was not stratified according to whether or not subjects participated in the MRI substudy. In 391 men (n=226) and women (n=165) aged 70 to 82 years (mean+/-SD, 75+/-3.2), we measured total CBF (in mL/min) at baseline and after a mean+/-SD follow-up of 33+/-1.4 months with a gradient-echo phase-contrast MRI technique. Total CBF was defined as the summed flows in both internal carotid and vertebral arteries. Parenchymal volume (whole brain) was segmented with the use of in-house-developed semiautomatic software. RESULTS: Total CBF significantly declined in the placebo-allocated group, from 521+/-83 to 504+/-92 mL/min (P=0.0036) and in the pravastatin-allocated group from 520+/-94 to 506+/-92 mL/min (P=0.018). This decline was not significantly different between treatment groups (P=0.56). There was also a significant reduction in brain volume over time (P<0.001), which was not different between the treatment groups (P=0.47). When expressed per unit of parenchymal volume, the decline in CBF over time was no longer statistically significant. CONCLUSIONS: Elderly people at risk for cerebral vascular disease had a significant decline in CBF with increasing age that was explained by a concomitant reduction in brain volume. Treatment with 40 mg pravastatin daily had no beneficial effect on total CBF.
Aged↗
Multisection CT as a valuable tool in the postoperative assessment of cochlear implant patients.
A data acquisition protocol for postoperative imaging of cochlear implants by using multisection CT (MSCT) is described. The improved image quality of MSCT allows assessment of the precise intracochlear position of the electrode array and visualization of individual electrode contacts. Such images can aid in fitting the speech processor, especially in difficult cases.
Adult↗
Age-related changes in normal-appearing brain tissue and white matter hyperintensities: more of the same or something else?
BACKGROUND AND PURPOSE: Cerebral white matter (WM) hyperintensities are a frequent finding in elderly people, and lowering of cerebral magnetization transfer ratio (MTR) has been observed. The aim of this study was to assess the relationship between age-related WM hyperintensities and MTR changes in the brain. METHODS: We performed MR imaging in a group of young subjects, a group of elderly individuals with minimal WM hyperintensities, and a group of elderly individuals with abundant WM hyperintensities. In addition, we performed volumetric MTR analysis of the whole brain and of the normal-appearing WM (NAWM) in these groups. RESULTS: Volumetric MTR parameters differed between elderly and young patients. Mean MTR +/- standard error of the mean (SEM) was 34.0% +/- 0.12% in the young, 33.0% +/- 0.08% in the elderly with minimal WM hyperintensities, 32.8% +/- 0.09%) in the group with abundant WM hyperintensities. Peak height (number of voxels +/- SEM) was 122 +/- 1.2 in the young, 99 +/- 1.5 in the elderly with minimal WM hyperintensities, and 98 +/- 1.6 in the group with abundant WM hyperintensities. Mean MTR of NAWM was lower in the elderly compared with the young (36.7% +/- 0.12%) but did not differ between subjects with minimal (36.0% +/- 0.11%) and those with abundant WM hyperintensities (35.9% +/- 0.13%). CONCLUSION: Our results show that aging gives rise to changes in normal-appearing brain tissue. These changes, which can be detected on magnetization transfer imaging, seem to have no relationship with age-related WM hyperintensities and might have a different etiology.
Adult↗