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PubMed1993

Right ventricular function at rest and during exercise in chronic obstructive pulmonary disease. Comparison of two radionuclide techniques.

Right ventricular function was assessed in 24 patients with COPD, at rest and during submaximal exercise, using both technetium-99m (99mTc) blood-pool and krypton-81m (81mKr) equilibrium ventriculography. Technetium-99m right ventricular ejection fraction (RVEF) at rest was lower than 81mKr RVEF (0.39 +/- 0.12 and 0.54 +/- 0.08, respectively; p < 0.001). During submaximal exercise, there was no increase in RVEF using either imaging technique. This observation contrasted with an increase in RVEF in a group of age-comparable normal subjects during modest submaximal exercise. An inability to obtain spatial separation of right heart structures using 99mTc imaging leads to a value for RVEF that is consistently lower than that measured using 81mKr ventriculography. Resting RVEF is well preserved at rest in most patients with COPD. In contrast to normal subjects, many show an inability to augment right ventricular function during exercise that may contribute to the reduced exercise capacity observed in these patients.

Aged↗
PubMed1993

Regional distribution of lung perfusion and ventilation at rest and during steady-state exercise after unilateral lung transplantation.

Cardiopulmonary exercise testing has previously demonstrated a reduced maximum oxygen uptake and anaerobic threshold, as well as abnormal wasted ventilation fraction and gas exchange after unilateral lung transplantation. To further explain the mechanisms of these abnormalities, we assessed the regional distribution of pulmonary blood flow and ventilation at rest and during steady-state exercise in nine recipients of unilateral lung transplants. Krypton-81 (81mKr) aerosol and technetium-99m (99mTc) were utilized to assess lung ventilation (V) and perfusion (Q), respectively. The digitalized images were trisected to analyze apical, mid-, and basilar lung perfusion and ventilation in both the transplanted and native lung, both at rest and steady-state upright exercise. Results were compared with previously reported data obtained in normal subjects in our laboratory using the identical technique. At rest, 75 +/- 13 percent of perfusion was directed to the transplanted lung; however, the corresponding fractional ventilation was only 67 +/- 14 percent. During exercise, there was no significant change in fractional perfusion or ventilation. Resting apical perfusion in the transplanted lung was higher than normal in four patients and comparable to normal in five patients. In contrast to the augmentation of apical perfusion observed in normal subjects during upright exercise, none of our patients increased the regional perfusion to the apices during exercise in either transplanted or native lungs. These unexpected responses suggest either more maximal allograft apical recruitment at rest due to the increased allograft perfusion or an abnormality in the apical pulmonary vasculature after transplantation. Furthermore, the relative mismatch in ventilation and perfusion in transplanted and native lungs suggests regions of high V/Q in the native, and low V/Q in the transplanted lung. This mismatch is most pronounced in recipients of single lung transplants for pulmonary vascular disease.

Adult↗
PubMed1994

Regional deposition and regional ventilation during inhalation of pentamidine.

In most patients, the deposition of aerosolized pentamidine (AP) is less in the apex of the lung relative to the base. As the apex of the lung is relatively less ventilated than the base, it is possible that reduced regional ventilation may explain the inhomogeneity in regional drug deposition. The purpose of this study was to measure the relationship between regional deposition of AP and regional ventilation, and the influence of particle size and airway caliber on this relationship. Ten subjects with HIV infection who were receiving prophylaxis with AP were recruited. Using krypton (81mKr), we measured regional ventilation during treatment with AP, labeled with 99mTc. Two nebulizers were used (Respirgard II and Fisoneb) that produced particles of different size. In addition, patients were studied with and without a bronchodilator because changes in airway geometry can affect sites of particle deposition. There was no significant correlation between regional ventilation and regional particle deposition (r = 0.00, linear regression). Particle deposition in the upper lobes relative to the lower lobes was less than would be predicted by regional ventilation, by a ratio of 0.84 +/- 0.03 (mean +/- SE). Using two-way analysis of variance (ANOVA), the upper to lower zone deposition pattern was not affected by either nebulizer or by the use of albuterol. The Fisoneb had significantly more central deposition relative to the jet nebulizer (mean +/- SE, skC/P: Fisoneb 1.3 +/- 0.1, Respirgard 1.1 +/- 0.1, p = 0.005, two-way ANOVA). The use of a bronchodilator did not significantly affect the central/peripheral deposition pattern. We conclude that differences in deposition between upper and lower lung regions are not accounted for simply by differences in regional ventilation in patients undergoing prophylaxis with AP. In assessing the cause of regional inhomogeneities of pharmaceutical aerosol deposition (and in devising strategies to achieve more uniform distribution), regional ventilation should be measured directly rather than be inferred from the deposition pattern of the aerosol.

Administration, Inhalation↗
PubMed1996

Noninvasive assessment of right heart function by 81mKr equilibrium radionuclide ventriculography in chronic pulmonary diseases.

Noninvasive multigated equilibrium radionuclide ventriculography with krypton-81m (81mKr) was used to assess right heart relaxation in patients with chronic pulmonary diseases (CPD). The subjects consisted of 30 patients with CPD and 8 patients free of cardiopulmonary diseases admitted to our department. A region of interest (ROI) was selected on both the right atrium (RA) and right ventricle (RV). A time activity curve was obtained for each ROI. As a diastolic index of the right heart performance, the right atrial early emptying rate (RAER) was obtained from the right atrial time activity curve, while the right ventricular rapid filling rate (RVRFR) was obtained from the right ventricular time activity curve. The mean RAER was significantly lower in CPD patients compared with the control (CPD, 9.5 +/- 4.5; control, 16 +/- 3.4%/100 ms). Similarly, the mean RVRFR was significantly lower in CPD patients compared with the control (CPD, 27.3 +/- 9.9; control, 34 +/- 8.5%/100 ms). A strong negative correlation was noted between the mean pulmonary arterial pressure (mPAP) and RAER (r = -0.77; p < 0.001) and between the mPAP and the RVRFR (r = -0.63; p < 0.001). Our results suggest that RAER and RVRFR measured by 81mKr are clinically useful in the noninvasive assessment of right heart relaxation in patients with CPD.

Adult↗
PubMed1985

Changes in distribution of lung perfusion and ventilation at rest and during maximal exercise.

A new method for evaluation of changes in the distribution of pulmonary perfusion and ventilation during exercise was applied to normal male volunteers. Ventilation and perfusion scans were done with the subjects seated on a bicycle ergometer. The resting studies utilized krypton 81 (81mKr) for ventilation and technetium 99m (99mTc) macroaggregate albumin intravenously for perfusion. Exercise studies were done when 80 percent of maximum predicted heart rate was maintained for five minutes and utilized 81mKr for ventilation and a tenfold dose of 99mTc for perfusion. Higher dose of 99mTc would minimize the effect of radioactivity left over from the resting study. This method allowed us to assess changes in ventilation and perfusion in normal subjects induced by exercise, but may also be applicable in a variety of cardiopulmonary conditions that affect pulmonary ventilation and perfusion or both.

Adult↗
PubMed1987

Noninvasive method to assess cor pulmonale in patients with chronic obstructive pulmonary disease.

In our study of 15 patients with chronic obstructive pulmonary disease, we performed myocardial perfusion single-photon-emission computerized tomography (SPECT) with thallium-201 to quantitatively assess right ventricular hypertrophy. On the SPECT images, we determined the ratio of activity in the right-to-left ventricular wall as the thallium score. Right ventricular ejection fraction (RVEF) was measured by multigated equilibrium radionuclide ventriculography with krypton-81m. Both the thallium scores and RVEF values correlated well with pulmonary arterial pressure (r = 0.65 and r = -0.86, respectively) and permitted the structural and functional assessment of cor pulmonale. When the patients were classified according to the thallium scores and RVEF values, those who had both a high thallium score and reduced RVEF had a significantly high pulmonary arterial pressure and vice versa. The combined evaluation of the thallium score and RVEF enabled accurate noninvasive assessment of cor pulmonale.

Adult↗
PubMed1995

Regional lung function following upper sleeve lobectomy for bronchogenic carcinoma.

Regional lung function of the operated side following upper sleeve lobectomy (n = 8) and simple upper lobectomy (n = 7) for lung cancer was evaluated. Regional ventilation was studied with Krypton 81m and regional pulmonary blood flow was studied with Technetium 99m. Measurements were taken from 12 to 24 months after operation. The ventilation rate of the operated side following right upper sleeve lobectomy (n = 5) was 42.9 +/- 6.7% and the perfusion rate was 37.4 +/- 4.6%. The regional ventilation rate of the operated side after simple right upper lobectomy (n = 3) was 45.9 +/- 10.5% and the perfusion rate was 46.2 +/- 5.2%. For the patients with left upper sleeve lobectomy (n = 3), these ratios were 29.9 +/- 11.1% and 19.2 +/- 3.6%, respectively. For the patients with simple left upper lobectomy (n = 4), these ratios were 27.3 +/- 4.5% and 22.3 +/- 3.3%. There were no statistical differences between the group with upper sleeve lobectomy and that with simple upper lobectomy. Regional function improved gradually with time. In conclusion, the regional lung function of the operated side following sleeve lobectomy was well preserved and showed no difference when compared with the regional function after simple lobectomy for lung cancer.

Aged↗
PubMedDate not supplied

Alteration in pulmonary blood flow induced by cold exposure to the hand in progressive systemic sclerosis.

To determine whether pulmonary blood flow is altered by cold exposure to the hand, cold exposure was induced by immersion of the left hand in 7 degrees C water in 8 patients with progressive systemic sclerosis (PSS). Lung perfusion was measured by continuous infusion of 81M krypton into the right antecubital vein. Exposing the left hand to cold caused an 11 to 32% decrease in the pulmonary blood flow in all lung fields in 4 of 8 patients. After release of cold exposure, in one of the 4 patients demonstrating a decrease during cold exposure, pulmonary blood flow recovered, while it kept on a decrease in the remaining 3 patients. Physiological abnormalities of pulmonary blood flow in PSS have been shown as a quantitative change and a image.

Cold Temperature↗
PubMed1993

Cause of regional ventilation-perfusion mismatching in patients with idiopathic pulmonary fibrosis: a combined CT and scintigraphic study.

OBJECTIVE: Regional ventilation and perfusion were studied in patients with idiopathic pulmonary fibrosis (cryptogenic fibrosing alveolitis) to seek an explanation for the mismatched ventilation/perfusion (V/Q) seen on scintigrams, which may suggest pulmonary embolic disease. SUBJECTS AND METHODS: Eight patients with idiopathic pulmonary fibrosis were examined with inspiratory and expiratory CT scans. Planar and tomographic (single-photon emission computed tomography, SPECT) scintigraphy, using inhalation of krypton-81m gas (ventilation) and IV injection of 99mTc-albumin macroaggregates (perfusion), also was performed. The lungs were divided into quadrants (cranial, caudal, right, left) for analysis. RESULTS: Cystic air spaces with a "honeycomb" appearance occupied more than 33% of the cross-sectional area in 75% of all lung quadrants (n = 16), more than 66% of the area in 44% of quadrants, and less than 33% of the area in the remaining 25% of quadrants. On expiratory CT scans, the cross-sectional area of the cystic spaces diminished significantly (unlike emphysematous spaces). Sixty-seven percent of lung quadrants, corresponding to those with marked or moderate involvement with cystic spaces, showed a mismatched V/Q pattern on scintigrams (absent perfusion, normal ventilation); 27% of quadrants had matched V/Q defects, and 6% did not show defects. Two patients had, in addition, large cystic spaces typical of emphysema, but the coexistent fibrosis prevented the gross air trapping seen in bullous emphysema. CONCLUSION: The cystic air spaces that are often seen on CT scans of patients with idiopathic pulmonary fibrosis are unperfused (probably due to vascular obliteration) but are usually normally ventilated. This V/Q mismatch on scintigrams explains the large physiologic dead space seen at rest and on exercise and could suggest pulmonary embolism unless a CT scan is obtained. Conversely, the larger cystic spaces might be mistaken for emphysema unless V/Q scintigraphy is done.

Adult↗
PubMed1987

An evaluation of two inert gas clearance techniques for measurement of endometrial blood flow in women.

Two methods utilizing inert gas clearance for the measurement of endometrial blood flow in non-pregnant women have been assessed and compared. A Krypton-85 rebreathing technique allowed measurement of superficial flow by means of an intrauterine semiconductor beta-detector probe. Intrauterine instillation of high specific activity Xenon-133 in small volumes of saline allowed endometrial flow measurement by gamma camera recording of the rate of clearance. Both these methods permitted calculation of absolute rates of flow and comparison of cyclical changes. Direct comparison of the techniques in the same women, and repeatability studies have shown good agreement, with calculated rates of absolute endometrial blood flow varying within the range 14-60 ml per 100 g tissue per minute. Vaginal blood flow measured simultaneously was always significantly lower (36-64%) than endometrial flow.

Adult↗
PubMed1982

Pentobarbital changes compartmental contribution to cerebral blood flow.

Barbiturates were administered to normal dogs, establishing an isoelectric electrocorticogram. Cortical cerebral blood flows (CBF) and deeper CBF's were respectively measured by krypton-85 (85Kr) and xenon-133 (133 Xe). Following barbiturate administration, the two methods of measuring CBF showed a poor coefficient of variation (r=0.12, p less than 0.05). The cortical flows decreased less than the fast compartment flows. A shifting of percentage contribution of flow to the slow compartment (60% increase, p less than 0.001) was observed after barbiturate infusion. A selective shunting of blood flow to the slower areas may explain the lowering of intracranial pressure and protection of the deep white matter observed by many authors who use barbiturates in clinical an experimental situations.

Animals↗
PubMed1991

Microvascular right-to-left pulmonary shunt demonstrated by a radionuclide method.

A 37-yr-old man with angiolymphoid hyperplasia (Kimura's syndrome), who had been treated unsuccessfully for suspected asthma, was investigated due to a decrease in arterial oxygen saturation (86%). Right heart catheterization and angiography of the pulmonary artery failed to demonstrate any right-to-left shunts. However, simultaneous scintigraphy over the lungs, kidneys, and head after injection of 150 MBq technetium-99m-labeled macroaggregated albumin i.v. and inhalation of 150 MBq krypton-81m demonstrated a right-to-left shunt in the lungs probably caused by precapillary pulmonary arteriovenous shunts.

Adult↗
PubMed1978

Studies of whole-body retention and clearance of inhaled noble gases.

The in vivo measurements of 127Xe and 79Kr clearance from the whole body indicate five components, with biologic half-times ranging from 13 sec to 17.04 h. The slowest component correlated highly with percent total-body fat, the half-time varying between 7.59 and 17.04 for xenon and between 4.20 and 9.62 h for krypton. The long-term retention was localized to regions of high fat content as determined by the coincidence mode of the whole-body counter and images obtained with the scintillation camera. The estimated dose based on the retention data of this study would indicate increased doses to body fat and gonads as compared with those previously calculated. These increased doses are due to the longer retention of noble gases in fat. After 10-min inhalations of a mixture of 127Xe and air and 79Kr and air, approximately one third of the total 127Xe and one fifth of the total 79Kr were transferred to the body tissues, extrapolated back to the start of gas washout. Of this amount, approximately 13% of the 127Xe and approximately 9% of the 79Kr were associated with the slowest component.

Adipose Tissue↗
PubMed1985

An evaluation of blood flow and perfusion in the canine pancreas.

This study evaluates pancreatic blood flow in the anaesthetised dog. Total flow was measured with an electromagnetic flowmeter and tissue perfusion using a Krypton-85 (85Kr) clearance technique. Cardiac output was also monitored with an electromagnetic flow probe placed on the ascending aorta. The flow and tissue perfusion in the pancreas were measured before and after devascularisation of the duodenum from the pancreas. The results show that the two techniques give similar values after pancreaticoduodenal devascularisation. If these vessels are left intact, however, electromagnetic measurements overestimate pancreatic flow by approximately 35%. Pancreatic blood flow in the dog is considered to have a normal value of 60-65 ml/min/100 g, or 25 ml/min, approximately 1.7% of the cardiac output being distributed to the gland.

Animals↗
PubMed1988

Effects of laser wavelengths on experimental retinal detachments and retinal vessels.

We studied the effects of the yellow (577 nm), orange (595 nm) and red (630 nm) dye lasers, the argon blue-green (488, 514.5 nm) and green (514.5 nm) lasers, and the krypton red (647 nm) laser on experimentally produced serous and hemorrhagic retinal detachments and on retinal vessels in rabbits. Retinal detachments were created by either injecting balanced saline solution or partially hemolyzed blood under the retina. All laser wavelengths except the argon blue-green bypassed the sensory retina and produced no damage on either the sensory retina or the underlying retinal pigment epithelium with serous retinal detachment. Each laser wavelength, however, produced a specific effect on the detached retina with hemorrhagic fluid. Blue-green, green, yellow and orange wavelengths damaged the sensory retina more severely than the red wavelengths. Laser coagulation of the retinal vessels with the blue-green, green and orange wavelengths produced vasospasms.

Animals↗
PubMed1987

[Right ventricular systolic and diastolic functions assessed by 81mKr scintigraphy and relation to ventricular septal ischemia].

Right ventricular (RV) systolic and diastolic functions were assessed in patients with previous anteroseptal myocardial infarction to ascertain the influence of interventricular septal ischemia on RV function. Gated right ventriculography with continuous infusion of krypton-81 m was performed in 12 normal subjects and 28 patients with infarction but without significant stenosis of the right coronary artery. Furthermore, RV contractile reserve by postextrasystolic potentiation was evaluated by gated radionuclide ventriculography with 99mTc-HSA. The patients with anteroseptal infarction were divided into two groups by the presence or absence of three hours' redistribution in the septal region on exercise thallium-201 myocardial scintigraphy. Two indices of systolic function (ejection fraction and the peak ejection rate) and three indices of diastolic function (1/3 diastolic filling rate, the peak filling rate and time to the peak filling rate) were derived from the right ventricular time-activity curve and its derivative curve. There was no difference in systolic function among normal subjects and patients with or without redistribution. However, diastolic function was impaired only in the patients without redistribution. The RV contractile reserve in the patients without redistribution was less than in those with it. Thus, RV systolic function was maintained in the patients with anteroseptal infarction, but contractile reserve deteriorated only in severe septal ischemia. Similarly, diastolic function was maintained in mild septal ischemia, but impaired in severe septal ischemia. We concluded that RV systolic and diastolic functions are closely related to interventricular septal ischemia.

Diastole↗
PubMed1985

Laser instrumentation and safety.

A review of the operation principles of lasers and the various types used in chest medicine is given. This includes CO2, Nd:YAG, argon, krypton, and dye lasers. Safety considerations in the use of lasers are also outlined.

Argon↗
PubMed1979

Methods of studying lobar and segmental function of the lung in man.

Making the decision whether a patient with chest disease can undergo lung surgery may be easier if the anatomical extent of the disease and the functional effects of resection can be estimated. Although information can be gained by non-invasive physiological studies of lung function of a routine kind, these cannot define the anatomical extent of the disease or distinguish the relative influence of affected and unaffected parts as estimates of lung function. Whole lung ventilation and perfusion scans provide immediate topographic information but have limited resolution and anatomical accuracy, particularly when the architecture of the lung is disturbed by disease. Bronchoscopy gives direct visual information about the more central airways but little or none about the function of the areas they serve. This paper gives brief descriptions of a series of procedures which could help in assessing the feasibility of lung surgery. The size, shape and volumes of individual lungs and lobes can be estimated from plain chest radiographs. Corresponding information about individual segments, and about lobes not delineated by normal X-ray, can be obtained using radio-active krypton 81m and a gamma camera during otherwise routine fibreoptic bronchscopy segments can be determined by simple single-breath manoeuvres at bronchoscopy using a respiratory mass spectrometer. The radio-isotope and spectrometric tests can be obtained in the same breath. The spectrometric tests can be recorded from more than one part of the lung within the same breath. All of the procedures give information in terms of anatomical units of interest to the surgeon.

Adult↗