Diagnosing dural metastases.
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Brain Neoplasms↗
Biomedical subjects
M Oudkerk
Publications and source records attributed to M Oudkerk.
Hypertension and cerebral white matter lesions in a prospective cohort study.
White matter lesions are frequently found on cerebral MRI scans of elderly people and are thought to be important in the pathogenesis of dementia. Hyper tension has been associated with the presence of white matter lesions but this has been investigated almost exclusively in cross-sectional studies. We studied prospectively the association of these lesions with the duration and treatment of hypertension. We randomly sampled 1077 subjects aged between 60 and 90 years from two prospective population-based studies. One-half of the study subjects had their blood pressure measured between 1975 and 1978 and the other half between 1990 and 1993. All subjects underwent 1.5 T MRI scanning; white matter lesions in the subcortical and periventricular regions were rated separately. Subjects with hypertension had increased rates of both types of white matter lesion. Duration of hypertension was associated with both periventricular and subcortical white matter lesions. This relationship was influenced strongly by age. For participants with >20 years of hypertension and aged between 60 and 70 years at the time of follow-up, the relative risks for subcortical and periventricular white matter lesions were 24.3 [95% confidence interval (CI) 5.1-114.8] and 15.8 (95% CI 3.4-73.5), respectively, compared with normotensive subjects. Subjects with successfully treated hypertension had only moderately increased rates of subcortical white matter lesions and periventricular white matter lesions (relative risk 3.3, 95% CI 1.3-8.4 and 2.6, 95% CI 1.0-6.8, respectively) compared with normotensive subjects. For poorly controlled hypertensives, these relative risks were 8.4 (95% CI 3.1-22.6) and 5.8 (95% CI 2.1-16.0), respectively. In conclusion, we found a relationship between long-standing hypertension and the presence of white matter lesions. Our findings are consistent with the view that effective treatment may reduce the rates of both types of white matter lesion. Adequate treatment of hypertension may therefore prevent white matter lesions and the associated cognitive decline.
Age Factors↗
Cerebral white matter lesions and subjective cognitive dysfunction: the Rotterdam Scan Study.
OBJECTIVE: To determine the relationship between cerebral white matter lesions (WML) and subjective cognitive dysfunction. BACKGROUND: Subjective cognitive dysfunction is present when a person perceives failures of cognitive function. When annoying enough, these failures will be expressed as complaints. Subjective cognitive dysfunction may be a prelude to or coincide with objective cognitive impairment. WML have been related to objective cognitive impairment and dementia, but their relationship with subjective cognitive dysfunction is not clear. Previous population-based studies on the latter relationship have been limited in sample size, recording of subjective cognitive function, and assessment of WML severity. METHODS: We randomly sampled 1,049 elderly nondemented participants from the general population. Data on subjective cognitive dysfunction and its progression were derived from a 15-item questionnaire. Objective cognitive performance was assessed using a series of neuropsychological tests. WML were scored on MRI for periventricular and subcortical regions separately. RESULTS: WML were associated with more subjective cognitive failures. WML were more severe for participants reporting progression of these failures compared with participants without these failures, especially within participants with better than average cognitive performance (p = 0.008, for periventricular WML). Participants with severe WML reported progression of cognitive failures more than twice as often than did those with little or no WML. The relationship between the severity of WML and subjective cognitive failures was present for periventricular and subcortical WML. CONCLUSIONS: WML are associated with subjective cognitive failures and in particular with reporting progression of these failures, even in the absence of objective cognitive impairment.
Aged↗
Four-dimensional cardiac imaging with multislice computed tomography.
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Angina, Unstable↗
[Screening for lung cancer in the Netherlands: the role of spiral CT scan].
The very poor prognosis of lung cancer has barely changed in the last two decades despite all efforts. However, prognosis is better when the disease is detected earlier, so that curative surgery or radiotherapy can be applied. Lung cancer screening in the past by chest X-ray did not lead to a decrease in lung cancer mortality, because the chest X-ray has low sensitivity for early invasive stages. With the advent of the low-dose spiral CT scan it has become feasible to detect early invasive stage I lung cancer in 80-90%. Modern screening for lung cancer by spiral CT scan could possibly decrease lung cancer mortality. Despite the first favourable results of screening the question remains whether lung cancer screening will be cost-effective. These questions can only be resolved in a randomised controlled trial with lung cancer mortality as unbiased end-point. Such a study should be initiated in the Netherlands, a country with large experience in screening trials and a good health care system. Only after lung cancer screening has proven to be cost-effective can appropriate implementation be recommended to prevent uncontrolled and opportunistic diffusion of this new screening technique into clinical practice in the near future.
Clinical Trials as Topic↗
Coronary angiography with multi-slice computed tomography.
BACKGROUND: A new generation of subsecond multi-slice computed tomography (MSCT) scanners, which allow complete coronary coverage, are becoming widely available. We investigated the potential value of MSCT angiography in a range of coronary disorders. METHODS: We studied 35 patients, including 11 who had undergone percutaneous transluminal coronary angioplasty and four who had had coronary-artery bypass grafts, by both MSCT and conventional coronary angiography. After intravenous injection of a non-ionic contrast medium with high iodine content, the entire heart was scanned within a single breath-hold. The total examination time was no more than 20 min. The retrospective electrocardiographically gated reconstruction source images and three-dimensional reconstructed volumes were analysed by two investigators, unaware of the results of conventional angiography. FINDINGS: In the 31 patients without previous coronary surgery, 173 (73%) of the 237 proximal and middle coronary segments were assessable. In the assessable segments, 17 of 21 significant stenoses (>50% reduction of vessel diameter) were correctly diagnosed. The non-assessable segments included four lesions. Misinterpretations were mainly the result of severe calcification of the vessel wall. Segments with implanted stents were poorly visualised, but stent patency could be assessed in all cases. Of the 17 segments of bypass grafts, 15 were assessable and four of five graft lesions were detected. Two cases of anomalous coronary anatomy could be visualised well. INTERPRETATION: These preliminary data suggest that MSCT allows non-invasive imaging of coronary-artery stenoses and has potential to develop into a reliable clinical technique.
Adult↗
MR spectroscopy detection of lactate and lipid signals in the brains of healthy elderly people.
Magnetic resonance spectroscopy was used to assess the presence of brain lactate and lipid signals, frequently associated with the presence of pathology, in healthy persons of 60-90 years old (n = 540). Lactate and lipid signals were observed in, respectively, 25 and 6% of women, and 18 and 2% of men. Upon adjustment for age, and for MRI-detected cerebral atrophy and white matter lesions, the gender differences in lactate and lipid remained the same (p = 0.05 and p = 0.03, respectively). Brain lactate and lipid signals appear to be intrinsic to aging. However, the presence of these metabolites in very focal areas only, rather than in any distributed fashion within the brain (the latter generally the case with cerebral atrophy and white matter lesions), strongly suggests the existence of asymptomatic focal pathology not shown on MRI.
Aged↗
Serum carotenoids and cerebral white matter lesions: the Rotterdam scan study.
OBJECTIVES: To study the relation between serum levels of carotenoids and white matter lesions (WMLs) on magnetic resonance imaging (MRI). DESIGN: Evaluation of cross-sectional data from a cohort study. SETTING: The Rotterdam Scan Study. PARTICIPANTS: Two hundred and three nondemented older persons, age 60 to 90, from the Rotterdam Scan Study. MEASUREMENTS: Serum levels of carotenoids were determined. WMLs on MRIs were rated separately into periventricular and subcortical WMLs. Odds ratios (ORs) for the presence of severe WMLs (upper decile) were calculated per standard deviation (SD) increase in serum carotenoid level and per SD increase in overall carotenoid serum level. Effect modification by smoking status was studied through stratified analyses. RESULTS: Increasing levels of all the separate carotenoids were associated with less severe periventricular WMLs, which reached statistical significance for the overall carotenoid serum level (OR 0.4 per SD; 95% confidence interval (CI) = 0.2-0.9). We found no association between carotenoid levels and the presence of severe subcortical WMLs (OR 1.2 per SD; 95% CI = 0.7-2.0). The association of carotenoid levels with severe periventricular WMLs was more marked in those who ever smoked (OR 0.1 per SD; 95% CI = 0.0-0.9) than in those who had never smoked (OR 0.9 per SD; 95% CI = 0.4-2.1). CONCLUSIONS: These findings are compatible with the view that high levels of carotenoids may protect against WMLs in the periventricular region, in particular in smokers. Longitudinal studies with repeated measurements of both carotenoids and WMLs are necessary to explore this hypothesis further.
Aged↗
Clinical validity of a normal pulmonary angiogram in patients with suspected pulmonary embolism--a critical review.
AIM: To determine the validity of a normal pulmonary angiogram in the exclusion of pulmonary embolism (PE), based on the safety of withholding anticoagulant therapy in patients with a normal pulmonary angiogram. MATERIALS AND METHODS: A review of English reports published between 1965 and April 1999 was carried out. Eligible articles described prospective studies in patients with suspected PE and a normal pulmonary angiogram, who remained untreated and were followed-up for a minimum of 3 months. Articles were evaluated by two authors, using pre-defined criteria for strength of design. End points consisted of fatal and non-fatal recurrent thromboembolic events. A sensitivity analysis was performed, by removing one study at a time from the overall results and by comparing pre- and post-1990 publications. RESULTS: Among 1050 patients in eight articles included in the analysis, recurrent thromboembolic events were described in 18 patients (1.7% 95% CI: 1.0-2.7%). These were fatal in three patients (0.3% 95% CI: 0.02-0.7%). The recurrence rate of PE decreased from 2.9% (95% CI: 1.4-6.8%) before 1990 to 1.1% (95% CI: 0.5-2.2%) after 1990. CONCLUSION: It would appear that the ability to exclude PE by angiography has improved over the years, as indicated by recurrence rate of PE. The low recurrence rate of PE supports the validity of a normal pulmonary angiogram for the exclusion of PE.
Anticoagulants↗
Human brain chemical shift imaging at age 60 to 90: analysis of the causes of the observed sex differences in brain metabolites.
RATIONALE AND OBJECTIVES: To assess whether differences in cerebral atrophy and white matter lesions or in the presence of lactate and lipid signals can explain the observed differences in brain choline, creatine, and N-acetylaspartate levels between healthy elderly women and men. METHODS: In addition to standard magnetic resonance imaging of the brain, an 8 x 8 x 2-cm3 supraventricular transverse brain volume parallel to the canthomeatal line was examined by magnetic resonance spectroscopy (automated 1H chemical shift imaging) in 540 healthy elderly persons. RESULTS: At P = 0.01, 0.001, and 0.0001, choline differed between women and men in 14, 9, and 5 of 36 voxels, respectively. On correction for cerebral atrophy (more frequent in men than in women), white matter lesions (more frequent in women), and lactate and lipid (more frequent in women), the differences in choline were reduced to 13, 6, and 3. Sex differences for creatine and N-acetylaspartate were similar but less numerous after correction. CONCLUSIONS: Elderly women and men in the general population show differences in the levels of creatine, N-acetylaspartate, and especially choline in portions of the brain. The sex-related differences in brain metabolite levels cannot be explained by differences in cerebral atrophy or other aging-related phenomena (white matter lesions, lactate, lipid).
Aged↗
Prevalence of cerebral white matter lesions in elderly people: a population based magnetic resonance imaging study. The Rotterdam Scan Study.
OBJECTIVE: White matter lesions are often seen on MR scans of elderly non-demented and demented people. They are attributed to degenerative changes of small vessels and are implicated in the pathogenesis of cognitive decline and dementia. There is evidence that especially periventricular white matter lesions are related to cognitive decline, whereas subcortical white matter lesions may be related to late onset depression. The frequency distribution of subcortical and periventricular white matter lesions according to age and sex reported. METHODS: A total of 1077 subjects aged between 60-90 years were randomly sampled from the general population. All subjects underwent 1.5T MR scanning; white matter lesions were rated separately for the subcortical region and the periventricular region. RESULTS: Of all subjects 8% were completely free of subcortical white matter lesions, 20% had no periventricular white matter lesions, and 5% had no white matter lesions in either of these locations. The proportion with white matter lesions increased with age, similarly for men and women. Women tended to have more subcortical white matter lesions than men (total volume 1.45 ml v 1. 29 ml; p=0.33), mainly caused by marked differences in the frontal white matter lesion volume (0.89 ml v 0.70 ml; p=0.08). Periventricular white matter lesions were also more frequent among women than men (mean grade 2.5 v 2.3; p=0.07). Also severe degrees of subcortical white matter lesions were more common in women than in men (OR 1.1; 95% confidence interval (95% CI) 0.8-1.5) and periventricular white matter lesions (OR 1.2; 95% CI 0.9-1.7), albeit that none of these findings were statistically significant. CONCLUSIONS: The prevalence and the degree of cerebral white matter lesions increased with age. Women tended to have a higher degree of white matter lesions than men. This may underlie the finding of a higher incidence of dementia in women than in men, particularly at later age.
Aged↗
Lung scintigraphy and helical computed tomography for the diagnosis of pulmonary embolism: a meta-analysis.
To assess the diagnostic value of lung scintigraphy and helical computed tomography (hCT) in patients with suspected pulmonary embolism (PE), all English-language articles that described lung scintigraphy and hCT in patients with suspected PE were retrieved. Articles were assessed for strength of methodology, based on nine a priori-defined criteria. Parameters of diagnostic accuracy and results of management studies were calculated and evaluated. Lung scintigraphy is diagnostic in approximately 50% of patients with suspected PE. A normal perfusion scan has a chance of recurrent PE in two of 693 patients (0.3%; 95% CI: 0.2-0.4%; fatal in 0.15%). A high-probability lung scan is correlated with angiographically proven PE in 308 of 350 patients (88%; 95% CI: 84-91%). Pulmonary embolism was proven in 385 of 1529 patients (25%; 95% CI: 24-28%) with a nondiagnostic lung scan. Helical CT studies were compared with angiography and lung scintigraphy in 1171 patients, with a prevalence of PE of 39%. The sensitivity and specificity of hCT was 283/320 (88%; 95% CI: 83-91%) and 374/408 (92%; 95% CI: 89-94%), respectively. Only one prospective management study using hCT was available. In patients in whom anticoagulants were withheld based on a normal hCT study, recurrent thromboembolic events occurred in six of 109 patients (5.5%; 95% CI: 2-12%), with one fatality (1%; 95% CI: 0.02-4.3%). Lung scintigraphy is evaluated extensively and yields a diagnostic result in 50% of patients. Helical CT has similar positive predictive value to a high-probability lung scan. However, the exact role of hCT in the management of patients with suspected PE needs to be determined in prospective studies.
Angiography↗
Lung cancer screening by low-dose spiral computed tomography.
The poor prognosis of lung cancer has barely changed in the last decades, but the prognosis is better when the disease is detected earlier. Lung cancer screening by chest radiography did not lead to a decrease in lung cancer mortality, presumably because the chest radiograph is a poor screening tool with low sensitivity. With the advent of the low-dose spiral computed tomography (CT) scan it has become feasible to detect early invasive stage I lung cancer in 8-90% of cases. This technique could possibly decrease lung cancer mortality, but the extent of this effect is as yet unknown, and whether lung cancer screening will be cost-effective is yet to be determined. These questions can only be resolved in a randomized controlled trial with lung cancer mortality as an unbiased end-point. In this review, the initiatives to evaluate low dose spiral CT screening for lung cancer in Japan, USA and Europe are presented. In the USA and Japan, evaluation is in one-armed studies, whereas in many European countries randomized trials are now being planned and several one-armed studies have been initiated. A formal collaboration among these countries has now been set up. It is strongly recommended that lung cancer screening be evaluated in randomized trials in order to allow evidence-based health policy decisions to be made on this subject.
Adenocarcinoma↗
Exclusion of pulmonary embolism using quantitative plasma D-dimer assays.
Recent quantitative studies using pulmonary angiography as reference method have indicated that the overall accuracy of quantitative D-dimer assays for the exclusion of pulmonary embolism (PE) in patients suspected of PE is poorer than was reported in earlier studies in which the same D-dimer assays were used (90-94% vs 98-100%). An explanation can be found in the fact that the earlier studies are hampered by the fact that the reference method was a compilation of clinical data and non-invasive diagnostic tests rather than a true gold standard. Furthermore, in those studies no discrimination was made between the milder cases of subsegmental PE and the more severe cases of segmental and larger PE. The lack of a true gold standard and preselection leading to reduced proportions of cases of subsegmental PE in the earlier studies rather than differences in the storage conditions of plasma samples or treatment with heparin, appear to have caused the discrepancies in the reported accuracy of D-dimer assays. It is concluded that the sensitivity and negative predictive values obtained with different quantitative D-dimer assays are in close agreement with each other, that is poor for subsegmental PE and excellent for segmental and larger PE. In diagnostic algorithms D-dimer can reliably exclude acute segmental and/or massive PE. Further work-up within 48 hours is still necessary in negative D-dimer outcomes to exclude subsegmental PE.
Antifibrinolytic Agents↗
Comparison of a quantitative latex and a quantitative ELISA plasma D-dimer assay in the exclusion of segmental and subsegmental pulmonary embolism.
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Angiography↗
Magnetic resonance angiography of a pulmonary artery stenosis late after cardiac surgery.
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Adult↗
[CBO guideline 'Deep venous thrombosis and pulmonary embolism; revision of the earlier guidelines. Dutch Organization for Quality Assurance in Hospitals].
Diagnosis of clinically suspected deep venous thrombosis is based on a clinical score, serial compression ultrasonography and D-dimer assay. For the diagnosis of pulmonary embolism perfusion scintigraphy, ventilation scintigraphy, echography of the leg veins and pulmonary angiography in that order lead to the lowest mortality, morbidity and costs. Diagnostics with spiral CT followed by pulmonary angiography leads to equal mortality and fewer angiography procedures. Decision rules based on anamnesis, physical examination, blood gas analysis and chest radiograph have proved to be insufficiently reliable. The present D-dimer assays have too little sensitivity and too much variability. Thrombo-prophylaxis with low-molecular-weight heparin is indicated for general surgery, joint replacement of the knee or hip, cranial and spinal surgery, subarachnoid haemorrhage after surgical treatment of an aneurysm, acute myocardial infarction, ischaemic stroke or spinal cord lesion, intensive care patients, patients with acute paralysis due to a neuromuscular disorder, and bedridden patients with a risk factor. Prophylaxis has to be continued as long as the indication exists. In the acute phase of deep venous thrombosis or pulmonary embolism treatment with (low-molecular-weight) heparin in an adequate dose is necessary. When started at the same time as coumarin derivatives the treatment with heparin has to be continued for at least 5 days. The risk of postthrombotic syndrome after deep venous thrombosis will be lowered by carrying compression stockings for at least 2 years after the event.
Anticoagulants↗
Coronary artery fly-through using electron beam computed tomography.
BACKGROUND: Virtual reality techniques have recently been introduced into clinical medicine. This study examines the possibility of coronary artery fly-through using a dataset obtained by noninvasive coronary angiography with contrast-enhanced electron-beam computed tomography. METHODS AND RESULTS: Ten patients were examined, and 40 to 60 transaxial tomograms (thickness, 1.5 mm; in-plane pixel dimensions, approximately 0.5x0.5 mm) were obtained after intravenous contrast injection. The datasets were processed on a graphics workstation using volume-rendering software. For fly-throughs, the contrast-enhanced lumen was made transparent and other tissue was made opaque. Then, key frames were selected in a path through the vessel, with software interpolation of frames between key frames. A typical movie contained 150 to 300 frames (10 to 15 key frames). Fly-throughs of coronary bypass grafts (n=3), left anterior descending arteries (LAD; n=6), and the intermediate branch (n=1) were reconstructed. Coronary calcifications were seen in 3 patients. The fly-through of the intermediate branch, the bypass grafts, and one of the LADs did not show any irregularities. In 2 cases, a stenosis was visible in the LAD; its presence was confirmed by conventional coronary angiography. CONCLUSIONS: Recent developments in fast-volume rendering using special-purpose hardware in combination with noninvasive coronary angiography with electron beam computed tomography have provided the possibility of performing coronary artery fly-throughs.
Calcinosis↗