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Biomedical subjects

A G Kessels

Publications and source records attributed to A G Kessels.

At least 19 recordsLinked to original sources
PubMed1998

Peripheral vascular tree stenoses: detection with subtracted and nonsubtracted MR angiography.

PURPOSE: To compare subtracted and nonsubtracted gadolinium-enhanced magnetic resonance (MR) angiography and cardiac-synchronized time-of-flight MR angiography for help in detecting pelvic-region stenoses. MATERIALS AND METHODS: Twenty-eight patients with intermittent claudication underwent MR angiography with a 1.5-T system; two-dimensional cardiac-synchronized time-of-flight MR angiograms and three-dimensional MR angiograms (without and with gadolinium enhancement) were obtained. Subtracted images were obtained by subtracting unenhanced data from enhanced data of identical volumes, and maximum intensity projection images were constructed, which two observers independently evaluated in blinded fashion, with conventional angiographic results as the reference standard. RESULTS: Sensitivity and specificity for grading of hemodynamically significant stenoses (> or = 50% lumen reduction) on subtracted MR angiograms were 94% and 93%, respectively. Sensitivity of subtracted images was significantly higher compared with that of time-of-flight images (P < .05) but not with that of nonsubtracted images. Contrast-to-noise ratio on subtracted images was significantly higher compared with that on nonsubtracted images (P < .05) but not with that on time-of-flight images. There was good correlation between stenosis length measurements on gadolinium-enhanced MR angiograms and those on conventional angiograms. CONCLUSION: Subtracted MR angiography is superior to cardiac-synchronized time-of-flight MR angiography for imaging of iliac and upper femoral arteries and provides higher contrast-to-noise ratio, fewer artifacts, and easier image interpretability than nonsubtracted MR angiography.

Angiography↗
PubMed1998

Peripheral vascular tree stenoses: evaluation with moving-bed infusion-tracking MR angiography.

PURPOSE: To evaluate a magnetic resonance (MR) angiographic technique for imaging of the peripheral arteries with gadolinium enhancement. MATERIALS AND METHODS: Moving-bed infusion-tracking MR angiograms were obtained in 15 healthy volunteers and in 28 patients with intermittent claudication before and during slow infusion of contrast material. Lower- and upper-leg and pelvic regions were imaged. Unenhanced images were subtracted from gadolinium-enhanced images, and maximum intensity projection images were generated. Image quality was evaluated subjectively and objectively, and maximum intensity projection images were compared with conventional angiograms, which served as the standard of reference. RESULTS: Moving-bed infusion-tracking MR angiography proved to be a robust technique, and image quality on maximum intensity projection images was comparable with that on conventional angiograms. Sensitivity and specificity for grading hemodynamically significant stenoses were 93% and 98%, respectively, with excellent interobserver agreement. CONCLUSION: Moving-bed infusion-tracking MR angiography can be used to image all peripheral arteries in 4 minutes by using a small amount of contrast material and a conventional 1.5-T MR imager.

Constriction, Pathologic↗
PubMed1997

On the prediction of the histologic composition of benign prostatic hyperplasia based on clinical and MRI parameters.

BACKGROUND: The histologic composition of prostate adenoma seems related to the development of clinical benign prostatic hyperplasia (BPH). Therefore, a new noninvasive prediction model as an alternative for biopsies was investigated. METHODS: In 19 patients, the data of a routine preoperative workup for transurethral resection (TURP) and of an additional MRI-examination were related to the results of morphometry on TURP-tissue. RESULTS: Statistical analysis identified age of the patient and MRI-volumetrics of the prostate adenoma as best predictors of the epithelial fraction, with a 95% confidence interval of at least 5% (range, 9-14%) (R2 = 50%). CONCLUSIONS: This prediction model is sufficiently accurate to categorize a population of patients into histologic subgroups. It seems very likely that this method will be of use as an investigative tool in medical trials to provide insight into the pathogenesis of clinical BPH and into treatment strategies for the individual patient.

Aged↗
PubMed1997

Prevalence and incidence of health problems in people with intellectual disability.

The objective of this study was to determine the prevalence and incidence of the most frequent chronic health problems in relation to age in people with intellectual disabilities living in residential facilities in the Netherlands. A prospective cohort study was done with four data collections, each with an interval of one year. Data were collected by means of questionnaires which were completed by each person's physician. Striking results included the reported high prevalence and incidence of visual and hearing impairment, which was even more pronounced in people with Down's syndrome than in people with intellectual disability resulting from other causes. Gastrointestinal problems also appeared to have high incidence rates. Dementia was frequently reported in people with Down's syndrome aged 40 years and older. The results reflect the need for a more predictive policy which can anticipate health problems in people with intellectual disability.

Adolescent↗
PubMed1997

Red and blue telangiectasias. Differences in oxygenation?

BACKGROUND: Leg telangiectasias are visible, ectatic dermal arteriols, capillaries, or veins with a diameter of 0.1-1 or 2 mm. Their origin is still not known and different opinions have been published. OBJECTIVE: In our study we were interested in the different colors of telangiectasias and we wanted to demonstrate whether a difference in blood gases is causing the difference in color between red and blue telangiectasias. METHODS: We measured a capillary astrup in 20 patients, who had red as well as blue telangiectasias on the lower limb. Therefore, we took two samples, one of a red and one of a blue telangiectasia. By this we measured the oxygen saturation and the carbon dioxide concentration of the samples. Furthermore, we introduced the appearance of telangiectasias in two rather newly developed techniques, such as high-frequency 20- and 50-MHz ultrasound and laser Doppler perfusion imaging (LDPI). RESULTS: Red telangiectasias of all 20 patients had an average oxygen concentration of 5.9 kPa, (range, 3.94-7.46 kPa); their average CO2 concentration was 5.45 kPa (range, 4.54-7.06 kPa). Blue telangiectasias had an average oxygen concentration of 5.11 kPa (range, 3.12-7.0 kPa); their average CO2 concentration was 6.07 kPa (range, 5.38-7.36 kPa). Statistically work-up with a paired student's t-test showed a higher oxygen saturation of the red telangiectasias and a higher carbon dioxide concentration of the blue vessels. CONCLUSION: As telangiectasias are assumed to be located in the capillary bed, the reason for differences in oxygenation could possibly be found in underlying physiological and anatomical principles of the capillary loops with the red telangiectasia representing the arterial loop of the capillary and the blue telangiectasia representing the venous loop of the capillary. With high frequency ultrasound and LDPI it is possible to get useful information for finding the underlying feeder veins, which "feed" the superficial telangiectasias. Injecting into the nutritional vessel telangiectases can potentially decrease the number of side effects and, may reduce the number of necessary injections.

Adult↗
PubMed1997

Pregnancy rate following normal versus abnormal hysterosalpingography findings: a meta-analysis.

A computerized Medline search was conducted, to assess the prognostic value of hysterosalpingography (HSG) and the probability of pregnancy after normal versus abnormal HSG findings. A total of 13 studies turned out to be eligible, reporting on 3,277 women. 15% of women with an abnormal HSG and 32% of women with a normal HSG achieved pregnancy. Sensitivities and specificities of the studies were heterogeneous. The pooled odds ratio was 3 (95% CI: 2.3-3.4). Its ROC Curve shows that, at the operating point yielding the lowest number of misclassifications, a sensitivity of 63% and a specificity of 62% is achieved. Seven studies reported unilateral and bilateral obstruction. Odds ratios were 2(95% CI: 1.5-2.6) and 19(95% CI: 7.5-46.5) respectively. So, overall, HSG has a low prognostic value, the outcome of HSG adds little to predicting the occurrence of pregnancy. However, when HSG shows bilateral obstruction, the chance of getting pregnant is only minimal.

Fallopian Tube Diseases↗
PubMed1997

Low diagnostic value of respiratory impedance measurements in children.

The aim of this study was to determine whether impedance values in children with various chronic respiratory complaints differed from those observed in symptom-free children. Respiratory impedance was measured using the forced oscillation technique in 1,776 Dutch children aged 6-12 yrs. In addition to the commonly used parameters of resistance and reactance, further impedance parameters were obtained by using linear and quadratic regression to describe individual resistance and reactance curves as a function of frequency. Furthermore, the diagnostic value of the individual impedance parameters was evaluated by means of receiver operator characteristic (ROC) curves. Statistically significant differences in impedance values were found in girls with symptoms suggesting asthma compared to symptom-free girls, but not in boys. In children with chronic cough, impedance was not significantly different from the values of symptom-free children. The results obtained by the additional impedance parameters were comparable to those of the commonly used measures. We conclude that the diagnostic values of the impedance parameters appeared to be low, as no cut-off points were found to discriminate clearly between symptomatic and symptom-free children. These findings may reflect absence of functional abnormalities in symptomatic children at this age.

Airway Resistance↗
PubMed1997

MR angiography of the iliac and upper femoral arteries using four different inflow techniques.

OBJECTIVE: The purpose of this study was to compare two inflow MR angiography pulse sequences obtained with and without systolic synchronization. We also compared these two MR angiography pulse sequences with conventional angiography. SUBJECTS AND METHODS: Thirty-one consecutive patients who were scheduled for conventional angiography because of symptomatic atherosclerotic occlusive disease of the iliac or femoral artery underwent MR angiography using four different MR angiography techniques. These techniques consisted of a multiple two-dimensional inversion prepulse gradient-recalled echo technique (turbo field-echo) obtained with and without systolic synchronization and a multiple two-dimensional gradient-recalled echo technique (fast field-echo) obtained with and without systolic synchronization. We then compared image quality and our ability to detect and grade degree and length of stenosis, using conventional angiography as the gold standard. RESULTS: The systolic-synchronized turbo field-echo sequence produced the best results both objectively and subjectively. Comparing systolic-synchronized turbo field-echo and fast field-echo techniques with conventional angiography regarding detection and grading degree of stenoses, we found no statistically significant differences. CONCLUSION: Systolic synchronization proved to be of significant importance for image quality. The systolic-synchronized turbo field-echo pulse sequence proved to be superior to the other three MR angiography techniques.

Aged↗
PubMed1997

Taking baths: the efficacy of balneotherapy in patients with arthritis. A systematic review.

OBJECTIVE: To review English, French, German, and Dutch language studies of the effectiveness of balneotherapy. Balneotherapy (hydrotherapy or spa therapy) is one of the oldest forms of therapy for patients with arthritis. One of the aims of balneotherapy is to relieve pain. METHODS: We performed a systematic review that included randomized and nonrandomized studies. Quality scores of the studies were determined using a criteria list. RESULTS: Most studies report positive findings, but all studies showed methodological flaws. A quality of life measurement was never reported as an outcome measure. None of the randomized clinical trials included intention-to-treat analysis or comparison of effects between groups. CONCLUSION: Because of the methodological flaws a conclusion about the efficacy of balneotherapy cannot be provided from studies we reviewed. We conclude that most flaws found could be avoidable in future research.

Arthritis↗
PubMed1996

Analgesic efficacy and safety of paracetamol-codeine combinations versus paracetamol alone: a systematic review.

OBJECTIVES: To assess whether adding codeine to paracetamol has an additive analgesic effect; to assess the safety of paracetamol-codeine combinations versus paracetamol alone. DESIGN: Systematic literature review with meta-analysis, methodological quality of published trials being scored by means of 13 predefined criteria. TRIALS: 24 of 29 trials that met the inclusion criteria. Models studied in the trials were postsurgical pain (21), postpartum pain (one), osteoarthritic pain (one), and experimentally induced pain (one). INTERVENTIONS: Dosages ranged from 400 to 1000 mg paracetamol and 10 to 60 mg codeine. MAIN OUTCOME MEASURES: The sum pain intensity difference (efficacy analysis) and the proportion of patients reporting a side effect (safety analysis). RESULTS: Most trials were considered of good to very good quality. Only the single dose studies could be combined for analysis of analgesic efficacy. Pooled efficacy results indicated that codeine added to paracetamol provided a 5% increase in analgesia on the sum pain intensity difference. This effect was comparable to the difference in analgesic effect between codeine and placebo. The cumulative incidence of side effects with each treatment was comparable in the single dose trials. In the multidose studies a significantly higher proportion of side effects occurred with paracetamol-codeine preparations. CONCLUSION: The difference is analgesic effect between paracetamol-codeine combinations and paracetamol alone was small but statistically significant. In the multidose studies the proportion of patients reporting a side effect was significantly higher with paracetamol-codeine combinations. For occasional pain relief a paracetamol-codeine combination might be appropriate but repeated use increases the occurrence of side effects.

Acetaminophen↗
PubMed1996

Effectiveness of antiepileptic prophylaxis used with supratentorial craniotomies: a meta-analysis.

Thirty publications on the effectiveness of prophylactic antiepileptic drugs (AEDs) with supratentorial craniotomies were reviewed (1980-1995). After a first selection, six controlled studies remained (11 publications). These six were evaluated according to previously defined methodological criteria. The criteria were divided into three main categories: (1) internal validity, (2) proper and relevant outcome-measures and (3) analysis. In this way a maximum of 145 points could be obtained for each study. Three studies were considered to be of satisfactory methodological quality (> or = 55% or 145 points) and the odds ratios were calculated as a measure of association between treatment and occurrence of convulsions. The odds ratios of these three studies were statistically pooled using the Mantel-Haenszel Estimator. From this test it appeared that prophylactically used AEDs showed a tendency to prevent postoperative convulsions, but this effect was certainly not statistically significant (P = 0.1 one-tailed). Points of attention concerning possible future investigations are stressed.

Brain Diseases↗
PubMed1996

Care dependence and activities of daily living in relation to ageing: results of a longitudinal study.

From 1990 to 1993, the University of Limburg and the Pepijn Centre, the Netherlands, have performed a prospective cohort study on ageing and intellectual disability. The key questions of the study were: "To what degree do the level of care dependence and activities of daily living (ADL) differ between age groups, and to what degree do these skills change during the study period (3 years)? Are the changes age related?'. Looking at the changes in time, the results show that the level of care dependence did not change substantially in the sample of 1602 residents of Dutch facilities for people with intellectual disability. Only the oldest residents (70+ years) showed a significant decline in independence. The results also show that the skills of young people with Down's syndrome (< 40 years) did not change substantially, whereas older people with Down's syndrome (40+ years) showed a substantial decrease in ADL-skills. The ADL-skills of the residents with other aetiological diagnoses younger than 60 years of age did not change substantially, while the older residents (60-69 and 70+ years) showed a significant decrease in ADL-functions. The trend between changes in ADL and age in both aetiological groups was statistically significant. Attention is paid to the implications of these findings in the discussion.

Activities of Daily Living↗
PubMed1996

Haematuria: intravenous urography, ultrasound or both?

PURPOSE: To compare the diagnostic value of intravenous urography (IVU), ultrasound (US) and their combination in detecting upper urinary tract malignancies in patients with haematuria. MATERIALS AND METHODS: In a prospective study, 360 consecutive patients who consulted the urologist for haematuria without renal colic were scheduled for IVU and US on the same day. The two procedures were performed by two different radiologists and reported independently. Histology or clinical follow-up of one year served as the gold standard. RESULTS: 63 patients dropped out. Of the remaining 297 patients, 9 (3%) had a malignancy in the upper urinary tract. Sensitivity and specificity with regard to the upper urinary tract pathology were 67% and 91% for IVU and 56% and 94% for US, respectively. For both techniques combined this was 79% and 88%, respectively. CONCLUSION: An acceptable sensitivity for detecting upper urinary tract malignancies is obtained only by combining IVU and US.

Adenocarcinoma↗
PubMed1996

A randomized clinical trial of ultrasound in the treatment of pressure ulcers.

BACKGROUND AND PURPOSE: The purpose of this study was to assess the effects of ultrasound (US) therapy in the treatment of pressure ulcers as an adjunct to standardized treatment. SUBJECTS: Eighty-eight patients from 11 nursing homes and one hospital participated. Subjects were randomly assigned to either a US group (n = 45) or a sham US group (n = 43). METHODS: This was a multicenter placebo-controlled randomized trial. Wound survival, healing rates of wound surfaces, and changes on a clinical rating scale were measured over 12 weeks. RESULTS: Comparison of the 12-week cumulative incidences of wound closure showed that 40% (18/45) of ulcers in the US group and 44% (19/43) of ulcers in the sham US group were closed. An analysis in which between-group baseline differences and the days of wound closures were accounted for showed that the wound closure probability per unit of time (ie, closure rate) was almost equal in the two treatment groups (Cox proportional-hazards ratio of 1.08). Mean absolute healing rates were 0.18 and 0.31 cm2/wk in the US and sham US groups, respectively. Relative healing rates and healing speeds were similar in the two treatment groups. A panel scored slides of the ulcers with a report mark between 1 (bad) and 10 (excellent). The improvement was 0.71 and 0.46 points per week in the US and sham US groups, respectively. CONCLUSION AND DISCUSSION: These data do not support the idea that US speeds up the healing of pressure ulcers.

Aged↗
PubMed1996

Renovascular disease in patients with hypertension: detection with systolic and diastolic gating in three-dimensional, phase-contrast MR angiography.

PURPOSE: To evaluate the usefulness of three-dimensional, phase-contrast magnetic resonance (MR) angiography performed with cardiac synchronization in the assessment of renal arteries. MATERIALS AND METHODS: Thirty-eight patients (24 men, 14 women) underwent three-dimensional, phase-contrast MR angiography without gating and with systolic and diastolic gating. Conventional angiography was used as the standard of reference. RESULTS: The sensitivity for the detection of all stenoses (> 0%) was 93% with systolic, 92% with diastolic, and 77% without gating. However, there was no difference between the three techniques in the diagnosis of hemodynamically significant stenoses (> 50%). The mean arterial length depicted was significantly better with diastolic gating than with either of the other techniques (P < .0001). Vascular disease was significantly overestimated with systolic gating relative to estimation without (P = .030) or with diastolic (P = .008) gating. CONCLUSION: Three-dimensional, phase-contrast MR angiography provides good image quality and enables assessment of renovascular disease. Cardiac gating has limited improvement of these results.

Angiography↗
PubMed1995

[Drug use by mentally handicapped persons in institutions and family-replacing residential facilities].

OBJECTIVE: Description of use of medication by people with mental handicaps in relation to age, level of mental handicap and living facility. DESIGN: Cross-sectional study. SETTING: Institutions and group homes for people with mental handicaps in North Brabant and Limburg, the Netherlands. METHODS: Of a patient sample (n = 1265), stratified according to age and living facility (i.e. institution or group home) data were collected by means of questionnaires to be completed by the general practitioners. For 101 persons data about level of mental handicap were lacking. RESULTS: 57% of the patients used one or more drugs. The numbers of drugs used were significantly related to (increased) age and level of mental handicap. Older patients more often used antipsychotics, laxatives and cardiovascular medication, younger ones more often used anticonvulsants. More severely handicapped persons used antipsychotics, anticonvulsants, laxatives, antacids, psychoactive medication and gastrointestinal medication more often. There was no relationship between amount of medication and living facility. CONCLUSION: Many mentally handicapped use medication. Since epilepsy, psychiatric and behavioural diseases and gastrointestinal problems are frequent, and because the patients offer little spontaneous information, alertness with respect to drug interaction and side effects is indicated.

Adult↗