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At least 1,693 records · Page 94Linked to original sources
PubMed1976

Blood flow in the small intestine of cat and man as analyzed by an inert gas washout technique.

Using a recently developed 85Kr-elimination technique, blood flow and flow distribution of the human small intestine have been investigated in patients during abdominal surgery. Total intestinal blood flow was estimated to be 38 +/- 4 ml per min and 100 g of intestinal tissue (mean +/- SE: n = 19), jejunal blood flow being slightly higher than ileal. In 14 of these patients muscularis blood flow was determined to be 21 +/- 2 ml per min and 100 g of muscularis tissue and mucosal-submucosal blood flow was calculated to be 51 +/- 6 ml per min and 100 g of mucosal-submucosal tissue. Seventy-five +/- 3% of total blood flow was distributed to the mucosa-submucosa and the remaining 25 +/- 3% to the muscularis. It was demonstrated that an increasing fraction of flow was diverted to the mucosa-submucosa with enhanced total intestinal blood flow. The human gut exhibited great qualitative and quantitative circulatory similarities with the feline small intestine.

Animals↗
PubMed1991

Non-invasive detection of reduced regional myocardial perfusion at rest in patients with unstable angina pectoris: increased regional 81mKr deposition following intravenous injection of 81Rb.

The present study was to investigate whether combined imaging of 81Rb and 81mKr distributions after i.v. injection of 81Rb at rest might improve the differentiation between ischemic and irreversibly damaged myocardium as compared to 201Tl scintigraphy at rest. In 21 patients who had undergone diagnostic cardiac catheterization for evaluation of chest pain, 148 MBq ultrapure 81Rb were injected i.v. at rest immediately following 201Tl scintigraphy at rest. Of 14 patients with earlier myocardial infarction, 10 patients revealed decreased regional tracer uptake of 81Rb and/or 81mKr, compared to 12 patients with regional 201Tl uptake abnormalities. In 3 patients with unstable angina pectoris, however, an evident mismatch between either the regional 201Tl or 81Rb distributions and the distribution of 81mKr was observed: in contrast to the reduced uptake of 201Tl and/or 81Rb, 81mKr activity was increased in 3 myocardial segments with normal left ventricular performance but supplied by coronary arteries with high-grade stenoses. In patients with contraindications to exercise tests (e.g. unstable angina) 81Rb/81mKr rest scintigraphy may therefore assist the differentiation between malperfused but potentially viable and irreversibly damaged myocardium.

Angina, Unstable↗
PubMed1991

[Laser application in celioscopic surgery].

The laser is certainly one of the most important discoveries of this century. Laser means: Light Amplification by Stimulated Emission of Radiation. The characteristics of laser radiation are coherence (same phase, amplitude and direction), monochromaticity, and collimation. Using by laparoscopy, it is possible to obtain cutting, vaporisation and hemostasis. Each laser is defined by wavelength specific for each different medical application. One should remember, however, that the laser is only an instrument, not a technic.

Argon↗
PubMed1991

[Assessment of right atrial and ventricular function by radionuclide ventriculography using continuous infusion of 81mKr].

The purpose of this study is to assess the right atrial and ventricular function by radionuclide ventriculography using continuous infusion of 81mKr in normal subjects and in patients with heart disease. 1) Reproducibility of RVEF measurement by continuous infusion of 81mKr was good (interobserver; gamma = 0.97, p less than 0.001, n = 20: intraobserver; gamma = 0.97, p less than 0.001, n = 20). This method had a excellent correlation with RVEF of 99mTc first-pass technique (gamma = 0.92, p less than 0.001, n = 20). 2) RVEF was measured in 10 normal volunteers, 76 patients with myocardial infarction (OMI), 20 patients with dilated cardiomyopathy (DCM), 5 patients with arrhythmogenic right ventricular dysplasia (ARVD) and 5 patients with primary pulmonary hypertension (PPH). In OMI and DCM, their RVEF was lower than that of normal volunteers and, in ARVD and PPH, lower than that of OMI and DCM. There was a significant inverse correlation between RVEF, mean pulmonary artery pressure and right ventricular end-diastolic volume index. 3) The effect of the location of right coronary artery (RCA) lesions on RVEF during exercise was also evaluated. Ten normal volunteers and 27 patients with OMI were studied at rest and during exercise. The patients with OMI were divided into two groups: those without proximal RCA lesions (non RCA group, n = 12) and those with proximal RCA lesions (RCA group, n = 15). Although there were no significant increases of RVEF during exercise in both group, the percent change in RVEF was less in RCA group than in non RCA group. These findings suggested that proximal RCA stenosis is a major determinant of exercise RVEF. 4) To assess the right atrial function, right atrial volume curve was measured in 10 normal volunteers, 32 patients with OMI and 4 patients with PPH. The curve was clearly divided into 4 phase; filling phase (312 +/- 40 msec), early ejection phase (276 +/- 53 msec), plateau an index of right atrial reservoir function, was 0.41 +/- 0.05 and Contractile Volume/Stroke Volume (Contr. V/SV), as an index of right atrial pump function, was 0.23 +/- 0.05 in normal volunteers. In OMI and PPH, atrial reservoir function decreased and atrial pump function increased. It was concluded that radionuclide ventriculography using continuous infusion of 81mKr was useful to assess the right heart function.

Atrial Function, Right↗
PubMed1991

Ventilation agents--what agents are currently used?

A survey of radiologists and nuclear physicians in 360 hospitals in the UK was undertaken to assess the current use of pulmonary ventilation agents. Replies were received from 340 (94%) hospitals. Of these, 200 (59%) provided lung scanning. The agents used for ventilation studies were Tc-labelled aerosols (118, 59%), 81Krm (58, 29%), 133Xe (42, 21%) and 127Xe (4, 2%). Nine (4.5%) hospitals performed perfusion scintigraphy without providing ventilation imaging. Thirty-two (16%) hospitals used more than one agent for ventilation imaging.

Humans↗
PubMed1990

[Determination of cerebral blood flow using an 81Rb/81mKr generator system].

A method is being developed which not only measures cerebral blood flow as a static quantity but also its changes with time. For that purpose a semiconductor device ascertains the proportion of intracerebral 81 Rb and 81mKr activities. By opening the hemato-encephalic barrier in animal experiments a sufficient concentration of intracerebral 81 Rb could be attained and the modified blood circulation after step-wise ligature of all brain arteries brought into relation to the corresponding Rb/Kr quotient. Over the range from undisturbed to completely interrupted cerebral blood flow this quotient varied up to 25% of its initial value.

Animals↗
PubMed1990

[Clinical evaluation of Kr-81m inhalation study through a dead space].

A new inhalation technique of 81mKr gas was applied to evaluate the pathophysiological abnormality of ventilation. 81mKr gas (370 MBq) was continuously supplied into a mouth piece directly (without dead space), VE, or through a dead space of 500 ml, VL, in 110 subjects with various lung diseases. Subjects were divided in four groups by a combination of distribution patterns of 81mKr gas obtained by these two inhalation techniques. Group 1: No ventilatory defect in both techniques. Group 2: Defects larger in VE than VL. Group 3: Defects larger in VL than VE. Group 4: No remarkable difference in defects in both techniques. Cases of group 1 were normal in pulmonary function test and chest X-ray. Finding of group 2 reflects early airway closure. This group consisted of cases in remission of bronchial asthma, small air way disease and pulmonary congestion. In group 3, restrictive disease and obstructive disease, especially emphysema, were included. Patients with severe obstructive disease and organized change of pulmonary parenchyma were belonged in group 4. In ventilation study with 81mKr gas, a combined study of inhalation technique through a dead space and by direct infusion may be useful to evaluate a pathophysiological change of various pulmonary diseases.

Administration, Inhalation↗
PubMed1990

[Pulmonary perfusion and ventilation scintigraphies before and after cardiac catheterization in infants with congenital heart diseases].

We performed 99mTc-MAA pulmonary perfusion scintigraphies before and after catheterization of 50 infants with congenital heart disease. 81mKr ventilation scintigraphies were also performed in 41 patients. Both right and left heart catheterization (23 patients) and right heart catheterization (27 patients) were performed by Seldinger's method. Pulmonary perfusion scintigraphies showed new perfusion defects in 6 patients (12%) following catheterization. Of six patients, three had ventilation defects. Clinical characteristics, duration of catheterization, hemodynamic variables were not significantly different between patients with and without lung perfusion defects. The lung perfusion defects seemed to be due to pulmonary embolism following cardiac catheterization.

Adolescent↗
PubMed1989

Effect of PEEP on regional ventilation and perfusion in the mechanically ventilated preterm lamb.

Improvement of gas exchange through closer matching of regional ventilation (V) and lung perfusion (Q) with the application of positive end-expiratory pressure (PEEP) was evaluated in vivo in six mechanically ventilated preterm lambs (107-126 days/145 days gestation). Changes in V and Q were determined from in vivo scintigraphic measurements in four lung regions with inhaled radioactive 81mKr, and infused 81mKr/dextrose and/or [99mTc]MAA as PEEP was applied at 2, 4, and 6 cm H2O in each animal. Dynamic compliance varied between 0.02 and 0.40 ml/cm H2O, which was consistent with surfactant deficiency. As PEEP was increased, the regional distribution of Q shifted from the rostral to the caudal lung regions (p less than 0.02 to less than 0.05), while that of V remained unchanged. Regional V/Q matching improved together with a trend towards improvement of arterial blood gases as PEEP was increased from 2 to 4 cm H2O. Pulmonary scintigraphy offers a noninvasive methodology for the quantitative assessment of regional V and Q matching in preterm lambs and may be clinically applicable to ventilated neonates.

Animals↗