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Biomedical subjects

A Bossuyt

Publications and source records attributed to A Bossuyt.

At least 37 records · Page 2Linked to original sources
PubMed1998

123I-5-I-R91150, a new single-photon emission tomography ligand for 5-HT2A receptors: influence of age and gender in healthy subjects.

5-HT2A receptors have been implicated in the pathophysiology of mood disorders and in the therapeutic effect of the so-called atypical antipsychotics. Recently, a new radioiodinated ligand with high affinity and selectivity for serotonin 5-HT2A receptors, 123iodinated 4-amino-N-1-[3-(4-fluorophenoxy)propyl]-4-methyl-4-piperidinyl] 5-iodo-2-methoxybenzamide (123I-5-I-R91150), has been developed and has been shown to be suitable for single-photon emission tomography (SPET) imaging. In this study the influence of age and gender on the ligand binding was investigated in normal volunteers. One hundred and fifty MBq of 123I-5-I-R91150 was administered to 26 normal volunteers (13 females and 13 males) with an age range of 23-60 years. SPET imaging was performed with a triple-headed gamma camera. For semi-quantitative analysis, ratios of ligand binding in different regions of interest to the binding in the cerebellum were calculated. Mean ratios of 1.7 were obtained. No gender difference was demonstrated. 5-HT2A binding was shown to decline with age. Over an age range of 40 years a reduction in ligand binding of 42% +/- 7% was found. These results are in agreement w in vitro and positron emission tomography findings of a decline in 5-HT2A receptor binding with age. The findings confirm the suitability of 123I-5-I-R91150 for SPET imaging of 5-HT2A receptors, and highlight the necessity for age-matched controls in clinical studies.

Adult↗
PubMed1998

The influence of cold and compression on lymph flow at the ankle.

OBJECTIVE: To investigate the effects of cold application with different temperatures on lymph flow in healthy persons and to examine the effects of the combination of cold and compression on lymph vessels. PARTICIPANTS: Thirty-nine healthy persons were included in the study, and each served as his or her own control. INTERVENTION: Water bags (1 degree, 15 degrees, and 32 degrees) with or without 25 mm Hg pressure were applied to the experimental legs for 30 minutes. Cold, pressure, or both were administered by an Aircast-Cryo-cuff (Aircast Europe GMBH, Rosenheim, Germany). MAIN OUTCOME MEASURES: Skin temperature was measured with a TESTO 901 (Testoterm GMBH, Leuven, Belgium) precision thermometer. Lymph flow was recorded continuously using lymphoscintigraphy. MANOVA with repeated measures was used for data analysis. RESULTS: As expected, skin temperature dropped relative to the temperature of the water. The migration of the tracer was comparable in both ankles during the first 30 minutes of the experiment (rest). When the water bag was applied, lymph flow increased significantly (p < 0.01). The application of water of 1 degree C without pressure influenced lymph evacuation significantly differently from the other temperatures. The application of pressure of 25 mm Hg influenced lymph evacuation significantly at 1 degree C and 32 degrees C. CONCLUSION: These results indicate that lymph evacuation at the ankle is influenced significantly when cold water is applied with or without pressure. When pressure is added to the application of water of 32 degrees C, lymph flow will also increase significantly, indicating the importance of pressure in lymph evacuation.

Adolescent↗
PubMed1998

Effect of oral glucose loading on the biodistribution of BMIPP in normal volunteers.

UNLABELLED: We have evaluated whether myocardial uptake of the fatty acid analog 123I-15-(p-iodophenyl)-3-R,S-methyl pentadecanoic acid (BMIPP) is dependent on the dietary state. METHODS: We compared the biodistribution of 150 MBq of 123I-BMIPP in six healthy volunteers in two states: after at least 12 hr of fasting and after oral glucose loading (75 g) 60 min before tracer administration, followed by a meal enriched in carbohydrates and protein. Planar and tomographic acquisitions were performed over a 4-hr time period after tracer injection; data were corrected for radioactive decay and injected dose. Radioactivity was measured in blood samples drawn at several points. RESULTS: Significant increases of glycemia and insulinemia and a significant drop in plasma nonesterified acids were documented after glucose loading. Half-time values for plasma radioactivity were significantly shorter in the glucose-loaded state than in the fasted state (4.3 +/- 1.4 min compared to 6.3 +/- 1.3 min, p < 0.05). Activity in the heart and liver tended to be higher in the glucose-loaded state than in the fasted state. SPECT images at 0.5 hr after tracer injection demonstrated that the myocardial wall-to-cavity ratio was higher after glucose than in the fasted state (2.53 +/- 0.59 compared to 2.11 +/- 0.21, p = 0.15). Washout from the liver between 1 and 4 hr after injection increased from 18.6% +/- 4.4% in the fasted study to 24.1% +/- 2.4% after glucose (p = 0.04). Washout from the myocardium between 0.5 and 3.5 hr after injection increased from 13.1% +/- 8.8% in the fasted study to 24.0% +/- 3.7% after glucose (p = 0.05). CONCLUSION: These results indicate that fasting before BMIPP scintigraphy is not mandatory to obtain adequate SPECT images. At the tire when SPECT is usually performed, glucose loading may provide improved ratios between myocardial and blood pool activity.

Administration, Oral↗
PubMed1997

Cerebral blood flow related to induction of a depressed mood within and out of the realm of attention in normal volunteers.

The effects of a depressed mood on regional cerebral blood flow (rCBF) were measured after a mood-induction procedure (MIP) in normal volunteers. The MIPs were administered 'within the realm of attention' and 'out of the realm of attention'. A modified Velten procedure, which consisted of tape-recorded self-referent depressive statements, was used for mood induction. For the induction out of the realm of attention, a combination of dichotic listening and subliminal stimulation was used. A neutral induction procedure served as a control condition. CBF was measured with Tc-99m HMPAO single photon emission computed tomography (SPECT) with regard to 14 healthy female students. Scores on mood rating scales showed negative changes after both MIPs. Statistical analyses revealed lateralized changes in rCBF in the thalamus. Decreased thalamic CBF in the right hemisphere was demonstrated after both MIPs compared with the neutral induction condition. Moreover, hippocampal rCBF increased significantly, but only after induction out of the realm of attention. These findings suggest both hippocampal and thalamic involvement in the regulation of mood experience.

Adult↗
PubMed1997

Fascial Tc-99m MDP uptake in eosinophilic fasciitis as demonstrated by SPECT.

BACKGROUND: The presence of bone-seeking radiopharmaceutical uptake in extraskeletal tissues of the lower or upper extremities may indirectly reflect the presence of active inflammatory lesions in patients in whom systemic disease is suspected. MATERIALS AND METHODS: The authors present the case of a 26-year-old woman who had mixed signs of scleroderma and cosinophilic fasciitis, in whom misleading findings on planar bone scintigraphy suggested diffuse muscular tracer uptake in the lower extremities. RESULTS: However, using additional SPECT imaging of the pelvis and thighs, it was shown that the soft tissue radioactivity was clearly restricted to the fascia overlying the muscles. The fascial localization of the inflammation was confirmed by biopsy. CONCLUSION: SPECT imaging was proven useful in indicating the exact localization of an active inflammatory process in the muscle fascia.

Adult↗
PubMed1997

Visualizing ocular melanoma using iodine-123-N-(2-diethylaminoethyl)4-iodobenzamide SPECT.

UNLABELLED: Radiolabeled benzamides have recently been introduced for the detection of melanoma. We evaluated the potential clinical applicability of 123I-N-(2-diethylaminoethyl) 4-iodobenzamide ([123I]IDAB) for SPECT imaging of ocular melanoma. METHODS: Fourteen patients were studied, 10 with or suspected of malignant ocular melanoma and four with ocular naevi. All patients underwent SPECT imaging of the head and whole-body scintigraphy 4-5 hr after injection of 170 MBq [123I]IDAB. RESULTS: A definite tracer hyperfixation was observed in the pathological eye in 9 of 10 (90%) patients with ocular melanoma. The pathological-to-normal eye ratio averaged 1.46 (range 1.07-2.86). The melanoma nature of the scintigraphic lesions was confirmed after enucleation in eight cases and by clinical evolution in two. A false-negative scan was reported in a patient with a small and hypochromic lesion. In patients with ocular naevi, no false-positive scintigrams were documented. CONCLUSION: Iodine-123-IDAB scintigraphy may contribute significantly to decide about enucleation in cases where some doubt persists with conventional techniques.

Benzamides↗
PubMed1997

Low back pain and nuclear medicine.

Low back pain (LBP) is a major cause of disability in many patients during some time of their lives. In this article the role of nuclear medicine, and more in particular the role of single photon emission tomography (SPECT), in the investigation of LBP is discussed by reviewing the literature. Because of the improved anatomical localization of lesions in the vertebral body when up-to-date SPECT is used, this technique is a powerful imaging modality in patients with LBP. Bone scintigraphy therefore can contribute significantly in the diagnosis of patients with LBP. In cases where conventional radiological techniques fail to elucidate the cause of LBP performing a bone scintigraphy with SPECT should strongly be recommended.

Diagnosis, Differential↗
PubMed1996

Optimal collimator choice for sequential iodine-123 and technetium-99m imaging.

Dual-isotope studies with technetium-99m and iodine-123 may be useful for various organs, including brain and myocardium. For the images obtained with each of the tracers to be comparable, it is important that activity ratios (activity in one part of the image/reference activity in the image) are preserved by the imaging method. We have used a Rollo phantom to study how collimator response affects such ratios. All investigations were performed with 123I(p,5n) and on a Siemens Orbiter 3700 camera fitted with either a low-energy high-resolution (LEHR) or a medium-energy (ME) collimator. Images were made of a Rollo phantom filled with an aqueous solution of either 99Tc or 123I, and placed on the collimator surface with 8 cm of methyl-methacrylate interposed. Count densities were measured in ROIs drawn in each cell of the phantom, and normalised to the maximal ROI value in the image. The mean square error (MSE) was used to assess how well the ratios of count densities approximated the known activity ratios based on the dimensions of the cells of the phantom. For 99mTc, regardless of the collimator used, the count density ratios approximated the activity ratios fairly well (LEHR: MSE=0.008; ME: MSE=0.020). For 123I, count density ratios obtained with the LEHR were consistently higher than activity ratios (MSE=0. 235), whereas the differences between the measured and the theoretical values were less with the ME collimator (MSE=0.013). Contrast fidelity of the 123I images obtained with the LEHR collimator could be improved with Jaszczak scatter correction with k=1, but this led to unfavourable signal-to-noise ratios. For sequential 99mTc/123I studies with extended sources, ME is to be preferred because of its higher contrast accuracy. Spatial resolution is less for the ME than for the LEHR collimator (FWHM with scatter: LEHR/99mTc=6.9 mm, LEHR/123I=7.4 mm, ME/99mTc= 10.1 mm, ME/123I=11.1 mm), but remains similar for both tracers when the ME is used.

Gamma Cameras↗
PubMed1996

Left ventricular ejection fraction from gated SPET myocardial perfusion studies: a method based on the radial distribution of count rate density across the myocardial wall.

Left ventricular ejection fraction (LVEF) can be derived from gated single-photon emission tomographic (SPET) myocardial perfusion studies using either manual or edge detection techniques. In the presence of severe perfusion defects, however, difficulties may be encountered. In this article a method based on the assumption that the average position of the myocardial wall can be localized by means of statistical analysis of the distribution count density, and not on edge detection, is used to measure LVEF. SPET myocardial perfusion images, gated in eight time bins, were recorded in 50 patients 60 min after the injection of 925 MBq technetium-99m tetrofosmin. Masking of non-myocardial structures and thresholding resulted in images in which only myocardial walls had significant non-zero values. The distance of the wall relative to the centre of the cavity was calculated in the three-dimentional space as the first moment of the count rate distribution along radii originating in the centre of the cavity. LVEF was calculated using, for each time bin, the sum of the cube of all distances as an estimate of the cavity volume. The method required minimal operator interventions and was successful in all patients, including those with severe perfusion defects. Intraobserver and interobserver variability was excellent, with regression coefficients of 0.97 and standard deviations of 4.5% and 4.7%, respectively. For 30 patients, the measurements were validated against planar equilibrium radionuclide angiography (ERNA) that was obtained within an interval of 1 week. LVEF ranged from 12% to 88%. Agreement between the two methods was excellent (LVEFERNA=1.05+0.92 LVEFGSPET, r=0.93, P=0.023, SEE=7.06). The Bland-Altman analysis did not show any apparent trend in the differences between ERNA and gated SPET over a wide range of ejection fractions. The standard deviation of the differences was 3. 1%. In addition no relationship was found between the two methods and the severity of perfusion defects. In conclusion, accurate measurements of LVEF are obtained from gated SPET perfusion images using a method based on statistical analysis of the count rate density. This method did not deteriorate even in the presence of severe perfusion defects and could therefore be used in following patients after myocardial infarction.

Aged↗
PubMed1996

Technetium-99m hexamethylpropylene amine oxime single-photon emission tomography of regional cerebral blood flow in insulin-dependent diabetes.

The study was performed to investigate subclinical abnormalities in regional cerebral blood flow (rCBF) in patients with insulin-dependent diabetes mellitus (IDDM) and to correlate them with patients characteristics. After intravenous injection of technetium-99m hexamethylpropylene amine oxime (HMPAO), tracer uptake of the prefrontal, frontal and parieto-occipital zones was measured with a triple-head single-photon emission tomography (SPET) camera system in 35 IDDM patients outside an episode of hypoglycaemia. Tracer uptake values in 16 age- and sex-matched healthy volunteers served as reference values. Compared with healthy subjects, increased tracer uptake of both prefrontal regions and the left frontal region could be shown in diabetes. Tracer uptake was negatively correlated with the duration of diabetes in all investigated regions. In diabetic patients with a disease duration of more than 5 years (n=26), stepwise regression analysis revealed a significant positive correlation between their HbA1c levels and tracer uptake. Long-term diabetic patients with reduced (pre)frontal tracer uptake (n=8) had lower HbA1c levels than those without (8.4%+/-0.2% vs 9.3%+/-0.3%, P<0.05) and tended to have more frequently a history of hypoglycaemic coma (6/8 vs 6/18, P=0.06). It can be concluded that duration of diabetes contributes to subclinical changes in basal rCBF in IDDM as detected with HMPAO SPET of the brain. The positive correlation between the presence of regional hypoperfusion and lower HbA1c levels in long-term diabetic patients may be interpreted in the light of a presumed higher incidence of hypoglycaemia as metabolic control improves.

Adult↗
PubMed1996

Comparison of 99m Tc HMPAO SPECT scan between chronic fatigue syndrome, major depression and healthy controls: an exploratory study of clinical correlates of regional cerebral blood flow.

An explorative analysis of the relationship between symptomatology and cerebral blood flow in the chronic fatigue syndrome (CFS) as assessed with 99mTc HMPAO SPECT scan reveals statistically significant positive correlations between frontal blood flow on the one hand and objectively and subjectively assessed cognitive impairment, self-rating of physical activity limitations and total score on Hamilton Depression Rating Scale on the other. A pathophysiological role of frontal blood flow in the cognitive impairment and physical activity limitations in CFS is hypothesized. A comparison of cerebral blood flow between CFS, major depression (MD) and healthy controls (HC) has been performed. A lower superofrontal perfusion index is demonstrated in MD as compared with both CFS and HC. There is neither a global nor a marked regional hypoperfusion in CFS compared with HC. Asymmetry (R > L) of tracer uptake at parietotemporal level is demonstrated in CFS as compared with MD.

Adult↗
PubMed1996

Renal technetium-99m-DMSA SPECT in normal volunteers.

UNLABELLED: Dimercaptosuccinic acid (DMSA) renal scintigraphy today is considered a sensitive and useful technique for the detection of cortical abnormalities. Recent studies have suggested that lesion detection can be improved by SPECT imaging. This study investigated normal kidneys using different SPECT modalities. METHODS: Ten young, healthy volunteers with normal clinical history and normal renal ultrasound underwent planar and SPECT DMSA imaging 2 to 4 hr after intravenous injection of 99mTc-DMSA (185 MBq). Analysis of SPECT data was focused on the homogeneity of cortical uptake (comparison of upper and lower pole activity) as well as on the presence or absence of focal cortical defects. RESULTS: No abnormality could be observed on the planar images. SPECT revealed, in seven kidneys (five left and two right), the presence of a hypoactive upper pole. This was visually observed on the coronal slices with up to 35% difference between upper and lower pole. Moreover, three focal cortical defects were visualized on the coronal slices as well as on three-dimensional surface shade displays. CONCLUSION: These normal patterns should be recognized when evaluating a patient with possible renal involvement.

Adult↗
PubMed1996

One-year follow-up of technetium-99m-HMPAO SPECT in mild head injury.

UNLABELLED: We evaluated the predictive capacity of 99mTc-HMPAO SPECT for clinical outcome during a follow-up period of 12 mo after mild head injury. METHODS: We prospectively evaluated 136 patients with mild head injury who underwent initial SPECT imaging (SPECTO) within 4 wk after the trauma. Re-evaluations were made 2.9-3.3 mo (T3mo), 5.7-6.3 mo (T6mo) and 11.9-12.6 mo (T12mo) postinjury. All patients with an abnormal SPECT underwent a repeat study at the subsequent time of evaluation. Patients with a previously normal SPECT scan did not undergo a repeat study. Clinical reassessments (CLIN) were performed as long as the earlier study had been positive or until patients were completely asymptomatic. RESULTS: During all follow-up evaluations, SPECT had a high sensitivity and negative predictive value, increasing from 91% and 89%, respectively, at T3mo to 100% at T6mo and at T12mo. Clinical normalization occurred earlier than scintigraphic normalization. However, at 12 mo postinjury, we observed considerable improvement in the specificity and positive predictive value of SPECT (85% and 83%, respectively). The persistent lesions on the SPECT scan were related to their severity and to localization in the frontal cortex. CONCLUSION: A normal 99mTc-HMPAO SPECT scan is a reliable tool in the exclusion of clinical sequelae of mild head injury. At 12 mo postinjury, a positive SPECT study is also a reliable predictor for clinical outcome.

Adolescent↗
PubMed1996

Exercise myocardial perfusion and wall motion imaging to predict recurrence of angina pectoris after successful angioplasty.

OBJECTIVES: This study investigates the predictive value of concurrent exercise radionuclide ventriculography and myocardial perfusion scintigraphy obtained six weeks after successful percutaneous transluminal coronary angioplasty for the recurrence of angina. METHODS: Both studies were obtained simultaneously with a single injection of technetium-99m sestamibi using the first-pass technique and the computerized tomographic technique, respectively. Ninety-five patients were investigated at rest and at maximal exercise 6 weeks after technically successful coronary angioplasty. RESULTS: Exercise-induced left ventricular dysfunction was present in 44 patients (46%). Exercise-induced myocardial perfusion defects were noted in 29 patients (30%). All patients underwent a six months follow-up. Seventeen patients (18%) had recurrent angina pectoris. Exercise-induced left ventricular dysfunction at six weeks after angioplasty was significantly associated with the recurrence of angina (p = 0.002), but exercise-induced perfusion defects were not. An abnormal left ventricular response to exercise was more sensitive than exercise-induced perfusion defects (82% versus 47%) to identify those patients with recurrent angina. The combination of both tests allows to select patients at a very high (40%) and very low (7%) risk of recurrent angina. CONCLUSION: Exercise-induced left ventricular dysfunction is more strongly associated with the recurrence of angina pectoris during a 6 month follow-up than are exercise-induced myocardial perfusion defects.

Adult↗
PubMed1996

99Tcm-DMSA renal scintigraphy for acute pyelonephritis in adults: planar and/or SPET imaging?

A number of authors have indicated a more sensitive detection of renal cortical defects using single photon emission tomography (SPET) compared with planar imaging when performing 99Tcm-dimer-captosuccinic acid (99Tcm-DMSA) renal scintigraphy. The place of SPET in the evaluation of kidneys in adults suspected of acute pyelonephritis (APN) remains controversial, however. The aim of this study was to address the role of SPET in adult patients suspected of having APN. Planar and SPET 99Tcm-DMSA renal imaging was performed in 53 patients. The data sets were separated and presented in random order to three independent observers. The kidneys were divided into three segments, which were classified as normal, definitely abnormal or equivocal. Ir. a second step, the number of lesions (definite or equivocal) on planar and SPET imaging were counted. The overall concordance between the planar and SPET imaging scores was 90.9, 89.9 and 87.7% for the three observers, respectively. Inter-observer discordance was recorded in a small percentage of both planar and SPET images. The number of lesions, based on the average of the three observers, was 22 for planar and 25 for SPET imaging. Obvious differences between observers were noted. The planar images were more often interpreted as equivocal by the least experienced observer. The more experienced observers gained limited additional information using SPET routinely. Most equivocal lesions on the planar scintigrams were observed in the lower segment. For SPET, no such distribution was noted. High-quality 99Tcm-DMSA images allow the detection of the same number of lesions as SPET in adults suspected of APN.

Acute Disease↗
PubMed1996

Prediction of functional outcome after myocardial infarction using BMIPP and sestamibi scintigraphy.

UNLABELLED: We determined the predictive value of combined beta-methyl iodophenyl pentadecanoic acid (BMIPP) and sestamibi scintigraphy for the functional outcome after myocardial infarction and compared the value of this approach with dobutamine echocardiography. METHODS: Rest BMIPP, rest sestamibi and low-dose dobutamine echocardiographic studies were obtained in 18 patients 4 to 10 days after infarction (mean 6.7 +/- 2.0 days). Six months later, a rest echocardiographic study was performed to assess functional outcome. RESULTS: Wall motion improved in 27/33 segments (82%) which showed mismatching but not in 19/21 segments (90%) with matched defects (p < 0.001). The accuracy of combined BMIPP and sestamibi SPECT in predicting segmental functional outcome was higher (85%) than that of sestamibi uptake alone (77%). Wall motion improved in 16/20 segments (80%) showing contractile reserve and not in 21/34 segments (63%) with the negative dobutamine test, giving an accuracy of 69% for dobutamine echocardiography. Combination of the two techniques resulted in higher positive (94%) and negative predictive values (94%). CONCLUSION: Mismatching of BMIPP and sestamibi uptake is predictive for long-term functional recovery after acute myocardial infarction. In contrast, segments with matched defects contain only scar tissue. Combined BMIPP and sestamibi scintigraphy offers increased accuracy compared to dobutamine echocardiography.

Coronary Angiography↗
PubMed1996

I-123-IDAB: a new tracer for scintigraphic visualisation of malignant melanoma.

I-123-N-(2-Diethylaminoethyl) 4-lodobenzamide (I-123IDAB) has recently been introduced as a radiopharmaceutical agent in the management of patients with malignant melanoma. We tested the diagnostic potential of this substance in 5 patients suspected of having an ocular malignant melanoma. I-123-IDAB scintigraphy identified 4 patients with high tracer uptake in the pathologic eye. Three cases were confirmed histologic as a malignant melanoma, the fourth patient was submitted to radiotherapy. The amelanotic (histologically confirmed) irismelanoma of the fifth patient could not be detected. From these preliminary results we conclude that I-123-IDAB scintigraphy may be a valuable tool for establishing the diagnosis of malignant melanotic melanoma.

Aged↗