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Biomedical subjects

A Bossuyt

Publications and source records attributed to A Bossuyt.

At least 55 records · Page 3Linked to original sources
PubMed1995

111In-octreotide scintigraphy: a tool to select patients with endocrine pancreatic tumors for octreotide treatment?

The results of octreotide scintigraphy, performed in two patients with malignant endocrine pancreatic tumors, were compared with the effect of somatostatin-14 and its analogue octreotide on hormonal levels and clinical outcome. Radiolabeled octreotide failed to demonstrate any tumor localisation in a patient with a malignant insulinoma. Nevertheless, IV injection of somatostatin and octreotide resulted in a significant decrease in peripheral insulin levels. Moreover in this patient, chronic treatment with a high dose of octreotide subcutaneously was able to transiently lower the incidence of hypoglycemic events. In a second patient with metastatic PP-oma, 111In-octreotide disclosed a pancreatic tumor in the tail of the pancreas and metastatic supraclavicular lymph nodes. In this patient IV administration of somatostatin and octreotide inhibited the hormonal secretion of the tumor but subcutaneous injection of octreotide induced hardly any decrease in plasma PP levels and failed to affect tumor growth. These observations find a possible reason for this in the heterogeneous affinity of the somatostatin receptors in endocrine pancreatic tumors. They indicate that octreotide scintigraphy alone should not be used to select patients with neuroendocrine tumors who can benefit from chronic treatment with the somatostatin analogue.

Adult↗
PubMed1995

Gastric emptying in critically ill patients is accelerated by adding cisapride to a standard enteral feeding protocol: results of a prospective, randomized, controlled trial.

OBJECTIVE: To investigate the effect of cisapride, a relatively new prokinetic agent, on gastric emptying in critically ill patients. DESIGN: Prospective, randomized, controlled study. SETTING: Adult medical/surgical intensive care unit in a university hospital. PATIENTS: Twenty-one consecutively enrolled patients, requiring prolonged mechanical ventilation and enteral feeding. INTERVENTIONS: Patients were randomized to receive either no cisapride or 10 mg of cisapride four times daily, which was added to a standard enteral nutrition feeding protocol. MEASUREMENTS AND MAIN RESULTS: Gastric emptying was evaluated by daily measurements of gastric residue and on days 5 through 7 by bedside scintigraphy. Normal values for gastric clearance of a tracer-labeled test meal and for measurements obtained in the supine position were determined in ten healthy volunteers. The mean time at which 50% of the technetium 99m-labeled test meal was eliminated from the stomach (T 1/2) in this control group was 31 +/- 15 mins. In ten critically ill patients (enteral nutrition group), gastric emptying was markedly delayed after 5 to 7 days of enteral feeding (mean T 1/2 = 78 +/- 40 mins; p < .002 as compared with the control group). In contrast, patients treated with cisapride (cisapride group) showed an accelerated gastric emptying (mean T 1/2 = 18 +/- 7 mins; p > .05 as compared with controls; p < .005 as compared with enteral nutrition group). The mean gastric residue over a 1-wk period was also significantly lower in the cisapride group than in the enteral nutrition group (17.7 +/- 8.9 vs. 94.5 +/- 33.4 mL; p < .001). CONCLUSIONS: The data indicate that gastric emptying in critically ill, sedated, and mechanically ventilated patients can be significantly improved by adding cisapride to a routine enteral feeding protocol.

Aged↗
PubMed1995

Regional cerebral hypoperfusion in long-term type 1 (insulin-dependent) diabetic patients: relation to hypoglycaemic events.

Regional distribution of cerebral blood flow was determined semi-quantitatively with 99Tcm-HMPAO brain SPET under basal conditions in Type 1 (insulin-dependent) diabetic patients of recent onset and longer disease duration, and related to metabolic control and history of hypoglycaemic events. Long-term diabetic patients showed significantly more alterations in regional cerebral blood flow than diabetics of recent onset and healthy controls. Regional hypoperfusion, predominantly localized in the fronto-temporal cortex, was almost exclusively observed in patients with long-term diabetes. The latter finding was related to lower HbA1c levels (i.e. better metabolic control) and to the frequency of impending hypoglycaemia, but not to age of the patient, duration of diabetes or to chronic diabetes complications. The incidence of hypoperfusion was comparable in patient groups with or without a medical history of hypoglycaemic coma. However, regions of hypoperfusion were larger in the patients who had experienced hypoglycaemic coma. It is concluded that regional cerebral hypoperfusion in long-term Type 1 (insulin-dependent) diabetics, as evidenced by HMPAO-SPET can be related to the frequency and degree of hypoglycaemic events and to tight metabolic control, which is however at the expense of an increased risk of recurrent hypoglycaemia.

Adult↗
PubMed1995

Combined left ventricular wall motion and myocardial perfusion stress imaging in the initial assessment of patients with a recent uncomplicated myocardial infarction.

UNLABELLED: The aim of the study was to examine the ability to simultaneously assess left ventricular function and myocardial perfusion by using a single injection of technetium-99m sestamibi at rest and during submaximal exercise to identify high-risk patients with left main, proximal left anterior descending (LAD), or three-vessel coronary artery disease (CAD) after an uncomplicated acute myocardial infarction (AMI). Multiple studies have evaluated the separate value of the exercise ECG, myocardial perfusion scintigraphy, and radionuclide angiocardiography (RNA) for identifying patients with severe CAD. The availability of technetium-99m (Tc99m)-labeled myocardial imaging agents offers the opportunity to evaluate simultaneously ventricular function and myocardial perfusion during a single exercise session. Only limited data are available about the value of this combined technique in the workout of patients early after an uncomplicated AMI. Combined first-pass RNA and myocardial perfusion tomoscintigraphy (SPECT) at rest and during submaximal exercise were performed in 52 patients, less than six weeks after an uncomplicated AMI, with use of Tc99m sestamibi. Patients were classified in two subgroups according to the presence of left main, proximal LAD, or three-vessel CAD. Stepwise logistic regression analysis was used to determine the independent predictors of severe CAD. All patients underwent the exercise testing without any medical complication. On univariate analysis, the global left ventricular ejection fraction (LVEF), wall motion score, and myocardial perfusion score, both at rest and at submaximal exercise, were significantly associated with the presence of severe CAD. The response of LVEF to exercise, and the presence of exercise-induced wall motion or myocardial perfusion abnormalities, were not associated with the severity of CAD. On multivariant analysis only the wall motion score during exercise was an independent predictor for the presence of severe CAD (P < 0.001, r = 0.6). In analyzing patients with anterior AMI separately, LVEF at submaximal exercise was the most accurate predictive parameter. If a cutoff value of 40% was chosen, the LVEF at exercise had a sensitivity of 85% and a specificity of 78% for the detection of severe CAD. In patients with inferior AMI, neither LVEF nor wall motion or myocardial perfusion scores were useful for differentiating the two subgroups. In these patients the presence of an additional perfusion defect during exercise in one of the anterior wall segments yielded a sensitivity of 70% and a specificity of 75% for the presence of severe CAD. IN CONCLUSION: simultaneous evaluation of LV function and myocardial perfusion at submaximal exercise, using a single injection of Tc99m-sestamibi, is a safe and accurate technique for selecting patients with severe CAD after an uncomplicated AMI.

Aged↗
PubMed1995

Technetium-99m-tetrofosmin in dipyridamole-stress myocardial SPECT imaging: intraindividual comparison with technetium-99m-sestamibi.

UNLABELLED: Tetrofosmin is a new 99mTc-labeled myocardial perfusion imaging agent. Biodistribution studies suggest more favorable heart-to-adjacent organ biokinetics than for 99mTc-sestamibi after injection during exercise. The aim of this work was to determine intraindividually whether tetrofosmin is more suitable than sestamibi for pharmacological stress testing in a 1-day protocol. METHODS: Thirty subjects underwent two similar 1-day, rest and dipyridamole stress imaging protocols: one using tetrofosmin, the other using sestamibi. SPECT was performed 60 min after tracer administration. Myocardial images were analyzed both visually and quantitatively. RESULTS: Heart-to-liver activity ratios measured on the anterior SPECT projections were significantly higher for tetrofosmin than for sestamibi in the rest and stress studies. Heart-to-lung ratios were similar for both tracers. Significant linear correlations between tetrofosmin and sestamibi perfusion indices were found in normals and in patients with proven or suspected coronary artery disease. In segments showing abnormal uptake during stress, the perfusion indices were similar for tetrofosmin and sestamibi at rest and during stress. The degree of reversibility in these segments was also similar for both tracers. Finally, the extent, intensity and severity of perfusion defects were similar for both tracer studies. CONCLUSION: Tetrofosmin has a more optimal biodistribution than sestamibi when used in a 1-day, rest and dipyridamole stress myocardial SPECT imaging protocol. No significant difference in either the quality or diagnostic interpretation of the images could be demonstrated.

Aged↗
PubMed1994

Dopamine D2 receptors in depression measured with single photon emission computed tomography.

Psychobiological theories of mood disorders have been concerned mainly with noradrenaline and serotonin. There exists, however, a recent upsurge of interest in dopamine. We have used single photon emission computed tomography and 123I-iodobenzamide, a high-affinity ligand for D2 receptors, to study these receptors in depression. Subjects were 21 (unipolar) depressed inpatients and 11 normal controls. The mean basal ganglia/cerebellum uptake ratio was 1.94 (+/- 0.27) in the depressed patients versus 1.74 (+/- 0.17) in the controls. This difference was statistically significant (Mann-Whitney U test, p = 0.025). These data could indicate an increase of D2 receptor density in depression.

Adult↗
PubMed1994

Radiation doses to those accompanying nuclear medicine department patients: a waiting room survey. EANM Task Group Explaining Risks. European Association of Nuclear Medicine.

In a multi-centre European trial we have assessed the radiation dose to those accompanying patients undergoing nuclear medicine investigations. Dosemeters were first calibrated against each other and then used to measure the radiation dose to the nurse or relative while they were in the waiting room. In departments where there was one waiting room the median radiation dose was 13 microSv, and the corresponding figures for where there were two waiting rooms and where the patients were allowed to leave the department with their nurse or relative were 12 and 11 microSv, respectively. These figures are not significantly different. However, we found that the median radiation dose to relatives was 13 microSv while that to nurses was 3 microSv (P < 0.01), although the waiting times were not significantly different. The reasons for these differences are discussed. Our data do not support the need for a second waiting room for injected patients in a nuclear medicine department.

Calibration↗
PubMed1994

Relationship between blood flow and fatty acid metabolism in subacute myocardial infarction: a study by means of 99mTc-Sestamibi and 123I-beta-methyl-iodo-phenyl pentadecanoic acid.

Contradictory data have been published on the relative behaviour of fatty acids and flow tracers during the subacute stage of myocardial infarction. Therefore, the present study was set up (1) to investigate the potential occurrence of mismatches between beta-methyl-iodo-phenyl pentadecanoic acid (BMIPP), a fatty acid analogue, and Sestamibi, and to describe their nature, and (2) to relate these mismatches to clinical characteristics such as whether or not thrombolysis or percutaneous transluminal coronary angioplasty (PTCA) had been performed. Twenty-six patients were studied within 2 weeks after myocardial infarction. Sestamibi and BMIPP single-photon emission tomography (SPET) were performed within 4 days of one another. Activity of both tracers was scored in 16 basal, 16 midventricular and 8 apical segments, using a four-point grading system: 3 = normal (> or = 65% of maximum activity), 2 = mildly decreased (45%-64%), 1 = moderately decreased (25%-44%), 0 = severely decreased (0%-24%). Coronary arteriography was obtained during the same hospital stay. Four hundred and seventy-seven segments out of 1040 studied were abnormal for at least one tracer: 197 with higher Sestamibi activity (group I), 226 with equal scores for Sestamibi and BMIPP (group II) and 54 with higher BMIPP activity (group III). Seventy-five percent of group I segments and 84% of group III segments were found in infarct-related artery territories. Group I segments were associated with acute thrombolysis and/or PTCA (P < 0.01), and with the absence of prior infarction in the territory of the infarct-related artery (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1994

Progressive diaphyseal dysplasia (Camurati-Engelmann's disease). Improvement of clinical signs and of bone scintigraphy during pregnancy.

The case of a woman suffering from progressive diaphyseal dysplasia is presented. Characteristic symptoms of crippling pain in both legs, severe aching in both forearms, and episodic temporofrontal and occipital headache were only partially regulated by corticosteroid treatment. However, pregnancy resulted in a progressive disappearance of these symptoms, allowing withdrawal of steroid treatment. Tc-99m MDP scintigraphy performed immediately after delivery showed a decrease of the intense uptake in the forearms, tibiae, and skull, which had been documented prior to pregnancy. However, widespread pain recurred within 6 weeks after delivery, accompanied by a recurrence of multiple severely hyperactive foci on bone scintigraphy. Alterations of immune modulated processes and changes in bone mineral homeostasis and in endogenous cortisol metabolism during pregnancy can be considered as possible explanations for the temporary improvement in clinical and scintigraphic signs of progressive diaphyseal dysplasia in this patient.

Adult↗
PubMed1994

Abnormal free fatty acid uptake in subacute myocardial infarction after coronary thrombolysis: correlation with wall motion and inotropic reserve.

UNLABELLED: Iodine-123-free fatty acid analogs, such as beta-methyliodophenylpentadecanoic acid (BMIPP), allow for myocardial metabolic studies with SPECT. The goal of this investigation was to determine whether BMIPP uptake can be used to differentiate viable myocardium from scar tissue soon after coronary thrombolysis for acute myocardial infarction. METHODS: BMIPP and 99mTc-sestamibi (MIBI) myocardial distribution after injection at rest were analyzed in 22 patients 4 to 10 days after coronary thrombolysis. The relative uptake of the two tracers was compared on a segmental basis to the regional wall motion and to the inotropic reserve assessed by two-dimensional echocardiography and low-dose dobutamine stimulation. RESULTS: Three segmental patterns were identified in the infarct-related coronary artery territory. Segments with normal BMIPP and MIBI uptake showed normal wall motion. Segments with more reduced BMIPP uptake than MIBI uptake (mismatching) showed either normal wall motion or demonstrated inotropic reserve during dobutamine stimulation. Segments with matched defects always showed abnormal wall motion and did not demonstrate inotropic reserve, regardless of the MIBI uptake. CONCLUSION: In patients with subacute myocardial infarction, combined imaging of BMIPP and MIBI at rest might be more sensitive than MIBI or wall motion at rest alone to demonstrate myocardial areas that have been acutely ischemic. Mismatching is due to more severely depressed fatty acid metabolism than expected on the basis of the flow and is indicative of jeopardized, but viable myocardium. In dysfunctional segments, mismatching may correspond either to stunned or to hibernating myocardium. Matched defects are associated with scar tissue.

Coronary Angiography↗
PubMed1994

Prospective evaluation of technetium-99m-HMPAO SPECT in mild and moderate traumatic brain injury.

UNLABELLED: We prospectively evaluated the contribution of 99mTc-HMPAO SPECT in patients who have sustained acute, mild or moderate head trauma. METHODS: Forty-two patients formed the first subgroup of moderate trauma (ModTr) and 25 patients formed the second subgroup of mild trauma (MilTr). All 67 patients underwent an initial SPECT (Tinit) within 4 wk after a closed cranial trauma. After a mean interval of 3 mo from the time of Tinit, all patients were clinically re-evaluated; those with an abnormal Tinit underwent a repeat SPECT (Trpt) as well. All SPECT studies were visually graded by agreement of three observers adjudging a score ranging from 0 (no lesions) to 4. RESULTS: For the group as a whole (ModTr + MilTr), the following results could be derived: (1) in 32/33 Tinit negative cases, clinical symptoms had resolved; (2) the positive predictive value of Tinit was only 20/34 (59%); (3) the sensitivity for the repeat SPECT was 19/20 (95%). CONCLUSION: Our results show that: (1) SPECT alterations correlate well with the severity of the trauma; (2) a negative initial SPECT study is a reliable predictor of a favorable clinical outcome; (3) in cases with a positive initial SPECT, a follow-up consisting of a combination of SPECT and clinical data is necessary; (4) in patients suffering from postconclusive symptoms, SPECT offers an instrument to objective sequelae.

Adolescent↗
PubMed1993

Regional distribution of 123I-(ortho-iodophenyl)-pentadecanoic acid and 99Tcm-MIBI in relation to wall motion after thrombolysis for acute myocardial infarction.

To characterize the myocardium after thrombolytic therapy for infarction single photon emission computed tomographic (SPECT) studies with 123I-(ortho-iodophenyl)-pentadecanoic acid (oPPA) and 99Tcm-methoxyisobutyl isonitrile (MIBI) were obtained at rest in nine patients within a fortnight after the acute event. A decreased oPPA activity compared to MIBI was observed in 15/45 segments (7/9 patients). The segments with discordant oPPA/MIBI activities showed less severe wall motion abnormalities than the segments with concordant decreased oPPA and MIBI activities (P = 0.004). A significant association was found between discordant oPPA/MIBI activities and the early evolution of wall motion following thrombolysis: discordant oPPA/MIBI activities were present in nine of the 11 segments (82%) with improved wall motion, while the wall motion of the seven segments with similar decreased oPPA and MIBI activities was unchanged or had deteriorated (P = 0.018). It is concluded that metabolic abnormalities often persist longer than perfusion and wall motion abnormalities soon after thrombolysis, and that 123I-oPPA in combination with 99Tcm-MIBI is useful to demonstrate myocardial areas which have been salvaged by thrombolysis.

Aged↗
PubMed1993

Semiquantitative analysis of cerebral blood flow by means of 99Tcm-HMPAO SPECT in individuals before and after a high altitude Himalayan expedition.

Nine members of the 'Belgian Tibet Expedition 1991' underwent a 99Tcm-hexamethylpropyleneamine oxime (HMPAO) brain single photon emission computed tomographic study before and after their stay at high altitude. Cerebral and cerebellar activity were analysed in three circumference profiles, representing the lower, middle and upper transaxial sections of the brain. The count value of each volume element (VE) was normalized to the maximum cerebellar value. In order to compare individual regional cerebral blood flow (rCBF) before and after the expedition, the relative differences in rCBF were calculated for each VE as: rel delta (%) = 100 x (value after expedition - value before expedition)/value before expedition. In 4/9 cases regional rel delta values were negative in most cortical regions; in 3/9 individuals nonsignificant changes were found and 2/9 climbers showed a positive rel delta value in most cortical regions. For the group as a whole there was (1) a mean decrease of 1.7% in global cortical CBF and (2) a significantly (P < 0.01) diminished rCBF was observed in both temporal and the left frontotemporal areas.

Adult↗
PubMed1993

Imaging of renal cell cancer with radiolabelled octreotide.

Recently the presence of somatostatin receptors on human renal cell carcinomas has been demonstrated by autoradiographic techniques on surgically removed kidneys. In a prospective study we evaluated, by means of 111In-labelled octreotide scintigraphy, the in vivo tumour imaging in a group of patients with biopsy proven renal cell carcinomas at different tumour stages. Seven patients were studied. In three of them (43%) pathological tracer accumulation was demonstrated. In these patients 20 out of 23 known tumour localizations were clearly visualized. Tracer uptake could be inhibited by prior administration of cold octreotide. We conclude that 111In-octreotide scintigraphy can be used to demonstrate, in vivo, metastatic renal cell carcinoma.

Aged↗
PubMed1992

Intraoperative radioactive localization of small bone tumours.

A sodium-iodide scintillation probe and a portable scaler rate-metre were used to localize small bone tumours at operation, after the preoperative injection of technetium-99m methylene diphosphonate. This technique allows complete removal of the tumour nidus of an osteoid osteoma or the active part of other lesions without undue sacrifice of the surrounding bone. The method has been used for successful relief of pain in thirteen patients.

Adolescent↗
PubMed1992

SPECT imaging of serotonin2 receptors in depression.

Changes of serotonin2 (5HT2) receptors have been described in depression, and long-term antidepressant treatment has been shown to decrease the number of 5HT2 receptors. In this study, single photon emission computed tomography (SPECT), with 2-123I-ketanserin as a ligand, was used to investigate 5HT2 receptors in vivo in the brain of depressed patients and normal volunteers. A higher uptake of the tracer was observed in the parietal cortex of the patients, and there was a right greater than left asymmetry in the infero-frontal region of the depressed subjects and not in that of the control subjects. These findings could indicate changes in 5HT2 receptors in major depression.

Adolescent↗