PubMed Health⌕ Search

Biomedical subjects

J van der Grond

Publications and source records attributed to J van der Grond.

At least 19 recordsLinked to original sources
PubMed2006

Intracranial compartment volumes in normal pressure hydrocephalus: volumetric assessment versus outcome.

BACKGROUND AND PURPOSE: Although enlargement of the cerebral ventricles plays a central role in the diagnosis of normal pressure hydrocephalus (NPH), there are no reports on the use of volumetric assessment to distinguish between patients who respond to ventriculoperitoneal shunt surgery and those who do not. The purpose of this study is to explore the association between preoperative intracranial compartment volumes and postoperative improvement. METHODS: Twenty-six patients (17 men; mean age, 75 years [range, 54-87 years]) with a clinical or radiologic suspicion of NPH were included in the study. Gait, cognition, and bladder function were evaluated by clinical rating. MR imaging of the brain was acquired at 0.5 T and 1.5 T. Total intracranial volume, ventricular volume, brain volume, and pericerebral CSF volume were determined by volumetric assessment. Four imaging variables were determined: ventricular volume ratio, brain volume ratio, pericerebral CSF volume ratio, and the ratio of ventricular volume to pericerebral CSF volume. All patients underwent ventriculoperitoneal shunt surgery. RESULTS: Clinical follow-up was assessed 1 year after shunt surgery. No difference in the mean ventricular volume ratio, the mean brain volume ratio, the mean pericerebral CSF volume ratio, and the mean ratio between ventricular and pericerebral CSF volume was found between subjects who improved on gait or cognition or bladder function and those who did not. CONCLUSION: Volumetric assessment has no predictive value in differentiating between NPH patients who respond to ventriculoperitoneal shunt surgery and those who do not.

Aged↗
PubMed2005

Fully automatic segmentation of white matter hyperintensities in MR images of the elderly.

The role of quantitative image analysis in large clinical trials is continuously increasing. Several methods are available for performing white matter hyperintensity (WMH) volume quantification. They vary in the amount of the human interaction involved. In this paper, we describe a fully automatic segmentation that was used to quantify WMHs in a large clinical trial on elderly subjects. Our segmentation method combines information from 3 different MR images: proton density (PD), T2-weighted and fluid-attenuated inversion recovery (FLAIR) images; our method uses an established artificial intelligent technique (fuzzy inference system) and does not require extensive computations. The reproducibility of the segmentation was evaluated in 9 patients who underwent scan-rescan with repositioning; an inter-class correlation coefficient (ICC) of 0.91 was obtained. The effect of differences in image resolution was tested in 44 patients, scanned with 6- and 3-mm slice thickness FLAIR images; we obtained an ICC value of 0.99. The accuracy of the segmentation was evaluated on 100 patients for whom manual delineation of WMHs was available; the obtained ICC was 0.98 and the similarity index was 0.75. Besides the fact that the approach demonstrated very high volumetric and spatial agreement with expert delineation, the software did not require more than 2 min per patient (from loading the images to saving the results) on a Pentium-4 processor (512 MB RAM).

Aged↗
PubMed2005

Proton MRS imaging in the follow-up of patients with suspected low-grade gliomas.

We compared the value of changes in proton magnetic resonance spectroscopic imaging ((1)H-MRSI) with changes in clinical status and/or contrast-enhanced magnetic resonance imaging (MRI) in the monitoring of patients with suspected low-grade glioma (LGG). From June 1, 1999 till May 31, 2002, we included consecutive, neurologically intact adult patients suspected of having an LGG, demonstrating non-enhancing supratentorial lesions without edema or mass effect on MRI, and in whom all treatment (including a diagnostic biopsy) was deferred. Till January 1, 2003, patients were surveyed clinically and radiologically (contrast-enhanced MRI and (1)H-MRSI). Patients who showed progression on clinical examination and/or MRI were denoted as progressive disease. Other patients were denoted as stable disease. A decrease in NAA/CHO ratio of > or =20% compared to the baseline value was considered as indicative for progression on (1)H-MRSI. We included 14 patients with suspected LGG. Seven patients demonstrated progressive disease during the follow-up period, preceded or accompanied by concomitant (1)H-MRSI changes in five patients. Four of these five patients were operated on within the follow-up interval. The histological diagnosis demonstrated high-grade glioma in three and LGG in one patient. In the other two patients with progressive disease, no progression was found on (1)H-MRSI. The other seven patients demonstrated stable disease, but four of them showed progression on (1)H-MRSI. Our data do not show convincing evidence that (1)H-MRSI contributes to adequate monitoring and follow-up of patients with suspected LGG. Future research should preferably include pathological data at the time of (1)H-MRSI changes.

Adult↗
PubMed2005

Cognitive deficits and changes in neurometabolites after a lacunar infarct.

In contrast to earlier observations, recent studies have demonstrated that supratentorial lacunar infarcts in the white matter may cause mild neuropsychological impairments. The origin of these cognitive disturbances is yet unknown. In the current study proton magnetic resonance spectroscopy (1H MRS) was used to elucidate the hypothesized relation between a lacunar infarct, metabolic alterations, and neuropsychological function. Patients with a single supratentorial lacunar infarct (n = 26) were compared with patients with a mild myocardial infarct (n = 12) and healthy controls (n = 12) on a comprehensive neuropsychological examination, and on the N-acetyl-aspartate/creatine, choline/creatine and lactate/creatine ratios. The volume of interest of the MRI/MRS examination was located in normal-appearing white matter of the centrum semiovale at a distance from the infarct, in both the ipsilateral and contralateral hemisphere. On neuropsychological examination patients with a lacunar infarct performed worse than both patients with a myocardial infarct and healthy controls. The N-acetyl-aspartate/creatine ratio was decreased in patients with a lacunar infarct compared with the other two groups. More important, this decrease in neurometabolites was significantly correlated to the level of cognitive functioning for the ipsilateral hemisphere and, although to a lesser extent, for the contralateral hemisphere. We conclude that a single symptomatic lacunar infarct in the white matter is associated with (distant) disturbances in neurometabolites and that this decrease is related to a reduced cognitive capacity.

Aged↗
PubMed2004

A fetal circle of Willis is associated with a decreased deep white matter lesion load.

OBJECTIVE: To investigate the relationship between morphologic differences in the circle of Willis and the presence and location of white matter lesions (WMLs). METHODS: Two hundred forty-three consecutive patients with clinical manifestations of atherosclerotic disease underwent MRI of the brain and MR angiography of the circle of Willis. RESULTS: Subjects with a fetal configuration of the circle of Willis demonstrated a decreased load of small (p < 0.01) and medium (p < 0.01) deep WMLs compared with subjects with a nonfetal configuration of the posterior part of the circle of Willis. CONCLUSION: A fetal configuration of the posterior part of the circle of Willis may be an important protecting determinant in the etiology of white matter lesions.

Aged↗
PubMed2004

Cognition and quality of life in patients with carotid artery occlusion: a follow-up study.

BACKGROUND: Little is known about long-term cognitive functioning and quality of life (QoL) in patients with symptomatic carotid artery occlusion who do not undergo revascularization surgery. OBJECTIVE: To assess the course of cognitive impairment and changes in QoL in these patients and whether impaired cerebral metabolism predicts the course of cognitive functioning. METHODS: In 73 consecutive patients with TIA or a minor stroke associated with an occlusion of the internal carotid artery (ICA), cognition and health-related QoL in a 1-year follow-up study were examined. The presence of cerebral ischemic lesions was examined by MRI; the metabolic N-acetyl aspartate/creatine ratio and the presence of lactate were measured by 1H-MR spectroscopy in the centrum semiovale ipsilateral to the symptomatic ICA occlusion. RESULTS: Seventy percent of patients with a stroke and 40% of patients with a TIA were cognitively impaired. In patients with recurrent TIAs during follow-up, cognitive functioning remained at the same (impaired) level (mean impairment score: at baseline 0.7, at 1-year follow-up 0.6; p = 0.646). In patients without lactate at baseline and without recurrent symptoms during follow-up, cognitive functioning improved (mean impairment score: at baseline 1.1, at 1-year follow-up 0.7; p < 0.001). Self-perceived QoL remained affected at 12 months' follow-up, although not to a large extent (mean SD from norm scores <1). CONCLUSIONS: In patients with a symptomatic ICA occlusion, cognitive functioning improved within 1.5 years after the ischemic event, if no further symptoms occurred and patients had no lactate at baseline. Self-perceived QoL remained slightly affected.

Brain↗
PubMed2004

Recurrent stroke in patients with symptomatic carotid artery occlusion is associated with high-volume flow to the brain and increased collateral circulation.

BACKGROUND AND PURPOSE: To investigate whether the risk of recurrent ipsilateral ischemic stroke in patients with symptomatic carotid artery occlusion (CAO) is related to (1) volume flow in the contralateral internal carotid artery (ICA), basilar artery (BA), and middle cerebral arteries (MCAs), and (2) intracranial collateral flow to the symptomatic side, measured in the first 6 months after the qualifying symptoms occurred. METHODS: We prospectively studied 112 patients with symptomatic CAO. Quantitative volume flow was measured with magnetic resonance angiography (MRA) and collateral flow via the circle of Willis with MRA, via the ophthalmic artery (OA) with transcranial Doppler sonography, and via leptomeningeal anastomoses with conventional angiography. RESULTS: During 49+/-14 months of follow-up (mean+/-SD), 7 patients had recurrent ipsilateral ischemic stroke. Compared with patients without recurrent stroke, these patients had significantly higher total flow to the brain, ie, ICA+BA flow (mean 536 mL/min versus 410 mL/min; P<0.05), and significantly higher contralateral ICA flow (355 mL/min versus 209 mL/min; P<0.001), whereas BA and MCA flow showed no significant differences. Also, they more often had Willisian collateral flow (P<0.05), mainly caused by increased collateral flow via the posterior communicating artery (PCoA; 71% versus 28%; P<0.05), whereas collateral flow via the OA and leptomeningeal anastomoses did not differ significantly. CONCLUSIONS: Recurrent ipsilateral ischemic stroke in patients with symptomatic CAO is associated with high volume flow to the brain and increased collateral PCoA flow.

Brain Ischemia↗
PubMed2004

High total cerebral blood flow is associated with a decrease of white matter lesions.

BACKGROUND: Low cerebral blood flow (CBF) has been associated with the presence of white matter lesions (WMLs). However, the power of these studies was insufficient (n=20-35) to determine whether flow is associated with WMLs. PURPOSE: The aim of this study was to investigate whether total cerebral blood flow (tCBF) is associated with the severity of white matter lesions (WMLs) in a large patient sample. SUBJECTS AND METHODS: 228 patients with clinical symptoms of cardiovascular disease had MRI of the brain, consisting of a T2-w FLAIR and a 2D phase-contrast flow measurement of the internal carotid arteries and the basilar artery. WMLs were graded according to prevalence and size of deep and periventricular WMLs. To determine the relation between tCBF and WMLs we used linear and logistic regression analysis adjusted for age, gender, intima media thickness and hypertension. RESULTS: We observed an inverse association between the tCBF and the total number of WMLs adjusted for age, gender, intima media thickness and hypertension [B=-1, 0 WML 95% CI (-2.0 to 0.0, p=0.045) per 100 mL increase in tCBF]. The adjusted odds ratio for the presence of severe WMLs in patients with high tCBF (> 675 mL/min) was 0.5 (95% CI 0.2-1.0) compared with patients with normal tCBF. CONCLUSION: In this study we found that high tCBF is associated with a decrease in presence and severity of WMLs.

Adult↗
PubMed2003

Collateral flow and ischemic brain lesions in patients with unilateral carotid artery occlusion.

OBJECTIVE: To investigate the association between ischemic brain lesions and intracranial collateral blood flow in patients with unilateral occlusion of the internal carotid artery (ICA). METHODS: Sixty-eight consecutive patients were included. Ischemic lesions on MRI were identified on hard copies, and volume measurements of the lesions were performed on an MR workstation. Intracranial collateral pathways were studied with MR angiography, digital subtraction angiography, and transcranial Doppler sonography. RESULTS: The presence of collateral flow via the anterior communicating artery (ACoA) was associated with a reduction in prevalence (p = 0.01) and volume (p = 0.008) of internal border zone infarcts in the hemisphere ipsilateral to the occluded ICA. Absence of collateral blood flow via the circle of Willis was associated with an increase in prevalence (p = 0.007) and volume (p = 0.005) of internal border zone infarcts. No association between any collateral flow pattern in the circle of Willis and periventricular lesions or lacunar, territorial, or external border zone infarcts was found. No association between collateral flow via the ophthalmic artery or leptomeningeal vessels with any type of ischemic lesion was found. CONCLUSION: Collateral flow via the ACoA is associated with a reduction of the prevalence and volume of internal border zone lesions but not with any other type of ischemic lesion. The presence of a functional posterior communicating artery or secondary collateral pathways is not associated with the prevalence of any type of ischemic lesion.

Adult↗
PubMed2003

Cerebral hemodynamics and metabolism in patients with symptomatic occlusion of the internal carotid artery.

BACKGROUND AND PURPOSE: The goals of this study were to investigate (1) whether the concentrations of choline, creatine, and N-acetyl aspartate (NAA) in cerebral white matter are changed in patients with symptomatic occlusion of the internal carotid artery (ICA) and (2) whether possible changes in metabolite concentration are related to regional cerebral perfusion or cerebral vasoreactivity. METHODS: In 19 patients (mean+/-SD age, 60+/-9 years), white matter metabolite concentrations were measured with proton MR spectroscopic imaging on average 4+/-2 months after symptoms occurred. In selected voxels, corresponding cerebral blood flow and volume, mean transit time, and time-to-bolus peak were determined with dynamic susceptibility contrast MRI. Cerebral CO2 reactivity was determined with transcranial Doppler sonography. RESULTS: No significant changes in choline and creatine concentrations were observed. NAA concentration was significantly reduced in the hemisphere on the side of the symptomatic ICA (9.1+/-1.7 mmol/L) compared with the contralateral hemisphere (10.5+/-1.7 mmol/L, P<0.005) and control subjects (10.5+/-0.9 mmol/L, P<0.01). Although no significant interhemispheric difference in NAA concentration was found in patients who presented with retinal ischemia, patients with cerebral ischemia had a significantly lower NAA concentration in the symptomatic hemisphere (9.0+/-1.7 mmol/L) compared with the asymptomatic hemisphere (10.4+/-1.6 mmol/L, P<0.05). In all patients, NAA concentration was not significantly correlated with quantitative cerebral perfusion parameters or CO2 reactivity. CONCLUSIONS: Patients with symptomatic ICA occlusion may show chronic neuronal damage in cerebral white matter as evidenced by reduced NAA concentration. This seems to be related to previous symptomatology rather than to the cerebral hemodynamic status in a chronic stage.

Aspartic Acid↗
PubMed2002

Relaxation times of choline, creatine and N-acetyl aspartate in human cerebral white matter at 1.5 T.

Several studies have investigated the T1 and T2 relaxation time of choline, creatine and N-acetyl aspartate in cerebral white matter in normal human subjects. However, these studies demonstrate a large variation in T1 and T2 values. In the present study, relaxation times of choline, creatine and N-acetyl aspartate were determined in cerebral white matter in 15 control subjects (age 21 +/- 2 y, mean +/- SD) at 1.5 T. Using PRESS, seven or eight data points were obtained to fit the T1 and T2 relaxation curves to, respectively. The mean voxel size was 14 cm3. The T1 relaxation times of choline, creatine and N-acetyl aspartate were 1091 +/- 132 (mean +/- SD), 1363 +/- 137 and 1276 +/- 132 ms. The T2 relaxation times were 352 +/- 52, 219 +/- 29 and 336 +/- 46 ms, respectively.

Adult↗
PubMed2002

Quantitative cerebral perfusion MRI and CO2 reactivity measurements in patients with symptomatic internal carotid artery occlusion.

Quantitative perfusion MRI is a promising new technique capable of offering information on cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). However, it is still unclear how these perfusion parameters relate to the underlying physiological indicators and how they compare to conventional techniques. The purpose of this study was to investigate how quantitative perfusion MRI is related to the cerebrovascular reactivity as measured by transcranial Doppler ultrasonography (TCD) in combination with a CO2 stimulus in patients with a symptomatic occlusion of the internal carotid artery (ICA). Thirty-nine patients with transient or minor disabling retinal or hemispheric ischemic symptoms and an occlusion of the ICA underwent quantitative perfusion MRI and CO2 reactivity measurements by TCD. Perfusion parameters were correlated with cerebrovascular reactivity measurements and compared with measurements of control subjects. The results of this study show a negative correlation between the cerebrovascular reactivity and the time to bolus peak (TBP) both for gray (r = -0.26, P = 0.035) and white matter (r = -0.28, P = 0.026). No correlation between resting CBV, CBF, or MTT and cerebrovascular reactivity was found. Our results indicate that an increase in TBP reflects a poor development of collateral flow, which is supported by a relatively low CO2 reactivity in these patients.

Adult↗
PubMed2001

Collateral ability of the circle of Willis in patients with unilateral internal carotid artery occlusion: border zone infarcts and clinical symptoms.

BACKGROUND AND PURPOSE: The circle of Willis is regarded as the major source of collateral flow in patients with severe carotid artery disease. The purpose of the present study was to assess whether the presence of border zone infarcts is related to the collateral ability of the circle of Willis in symptomatic (transient ischemic attack, minor stroke) and asymptomatic patients with unilateral occlusion of the internal carotid artery (ICA). METHODS: Fifty-one patients (35 symptomatic, 16 asymptomatic) and 53 control subjects were investigated. Patients had unilateral occlusion of the ICA and contralateral ICA stenosis between 0% and 69%. The directions of flow, on the side of the ICA occlusion, and the size of the component vessels in the circle of Willis were investigated with MR angiography. RESULTS: On average, 92% of the patients without border zone infarcts (n=26) had willisian collateral flow compared with 60% of patients with border zone infarcts (n=25; P<0.05). This increase in collateral flow was caused by the high prevalence of collateral flow via the posterior communicating artery in patients without border zone infarcts (50% versus 12%; P<0.05). No statistically significant relation was found between the pattern of collateral flow via the circle of Willis and the presence of clinical symptoms. Nevertheless, asymptomatic patients with ICA occlusion demonstrated an increased diameter of the anterior communicating artery (P<0.05). CONCLUSIONS: In patients with unilateral ICA occlusion, the presence of collateral flow via the posterior communicating artery in the circle of Willis is associated with a low prevalence of border zone infarcts. Asymptomatic patients with an ICA occlusion do not have an increased collateral function of the circle of Willis.

Adult↗
PubMed2001

Magnetic coupling between water and creatine protons in human brain and skeletal muscle, as measured using inversion transfer (1)H-MRS.

Using the inversion transfer technique, the possible magnetic coupling between water protons and the protons of low-molecular weight metabolites was investigated in human brain and skeletal muscle at 1.5 T. The localized (1)H-MR spectra were recorded at different times after selective inversion of the water resonance. Water inversion led to a significant transient reduction in the signal intensity of the methyl protons of creatine/phosphocreatine, in both tissues. This is indicative of magnetic coupling between the protons of water and those of creatine/phosphocreatine. Neither the choline and N-acetylaspartate protons in brain nor the protons of the trimethylammonium pool in skeletal muscle showed a significant magnetic coupling to mobile water.

Brain Chemistry↗
PubMed2001

Cerebral blood flow in relation to contralateral carotid disease, an MRA and TCD study.

OBJECTIVE: to describe redistribution of cerebral blood flow in patients with severe internal carotid artery (ICA) stenoses in relation to contralateral ICA disease. METHODS: sixty-six patients scheduled for carotid endarterectomy (CEA) were grouped according to severity of contralateral stenosis (<30% [group I]; 30-69% [group II]; 70-99% [group III]; occlusion [group IV]. Transcranial Doppler (TCD) and magnetic resonance angiography (MRA) investigations were performed preoperatively. RESULTS: TCD demonstrated a reversed flow in the contralateral anterior cerebral artery (A(1)segment) and ophthalmic artery in three-quarters of group IV patients (p <0.0001). Group IV patients also exhibited decreased blood flow velocity in the contralateral middle cerebral artery (p =0.001). MRA showed increased ipsilateral ICA and basilar artery (BA) blood flow volumes (Q-flows) in group IV patients when compared to the other groups (p <0.001). No changes in total Q-flow (ICAs+BA) were found. CONCLUSIONS: in patients considered for CEA, the severity of the contralateral ICA disease is an important determinant of the pattern of blood flow redistribution through the anterior communicating pathway and ophthalmic artery. Significant flow redistribution through the posterior communicating pathway occurs especially in patients with contralateral ICA occlusion.

Adult↗
PubMed2001

Cerebral proton magnetic resonance spectroscopy of neonates after extracorporeal membrane oxygenation.

UNLABELLED: During venoarterial extracorporeal membrane oxygenation the right carotid artery is ligated in a hypoxic neonate. The aim of the present study was to compare the morphology and metabolism of the left and right basal ganglia in 10 neonates after extracorporeal membrane oxygenation, using proton magnetic resonance imaging and spectroscopy. Data could be obtained in 9 neonates. No significant metabolic differences were found between either the left or right basal ganglia, despite a small right-sided thalamic infarct in one child. Metabolism was normal in all cases. All the infants showed symmetrical neurodevelopment. CONCLUSION: Ligation of the right carotid artery for venoarterial extracorporeal membrane oxygenation did not produce persistent changes in brain metabolism in the basal ganglia in this small group of patients.

Basal Ganglia↗