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At least 1,405 records · Page 78Linked to original sources
PubMed1976

Measurement of regional myocardial blood flow in dogs using a catheter semiconductor radiation detector.

Simultaneous total left coronary and regional myocardial blood flow were measured by injecting 85Kr into the left coronary artery and recording its clearance using a precordial gamma detector and a catheter tip beta detector (CASRAD) placed directly on selected regions of the myocardium. There were no significant differences between total left coronary (175 ml-100 g-1/min) measured by the precordial gamma detection and regional myocardial blood flow (183 ml-100 g-1/min) determined in the area of the left anterior descending coronary artery (LAD) by the beta detector in five open chest dogs. After ligation of the LAD regional clearance of 85Kr ceased in the area of myocardium distal to the ligation while total coronary blood flow decreased only slightly from 152 to 126 ml-100 g-1/min. Measurement of regional myocardial blood flow by CASRAD may be of value in determining the extent of myocardial ischaemia in experimental animals and assessing the effect of therapeutic interventions.

Animals↗
PubMed1976

Brain-blood partition coefficients of 85Krypton at 37 C and 29.5 C.

To permit utilization of the Kety-Schmidt technique for measuring cerebral blood flow during hypothermia, the brain-blood partition coefficients for 85krypton at 37 C and 29.5 C were determined in a series of cats. At 37 C the partition coefficient for 85krypton was 1.092 +/- 0.009; it was 0.931 +/- 0.007 (SE) at 29.5 C. These values were significantly different from each other (P less than .001).

Animals↗
PubMed1981

Demonstration of a bronchopleural communication by inhalation of Kr-81m gas.

Suspicion of a persisting communication between the bronchial tree and the pleural space in a patient with surgically drained pneumothorax was confirmed by the inhalation of Kr-81m gas. Compared to other diagnostic methods, this technique is harmless and repeatable, and hence very convenient for the assessment and follow-up of persisting pneumothorax due to air-leaks and of bronchopleural fistulas of any cause.

Bronchial Fistula↗
PubMed1981

Radionuclide venography using continuous Kr-18 m infusion: preliminary note.

Continuous infusion of Kr-81m presents important advantages compared to the commonly used radionuclides for venography. High count rates can be accumulated, and a high resolution collimator can be employed to ensure good quality images. The study can be repeated immediately and multiple views can be performed until a satisfactory result is obtained. The production of radionuclide from a Rb-81--Kr-81m generator suitable for intravenous infusion is almost the same as that which is suitable for ventilation. The same generator can first be used for venography and then for ventilation imaging to complete the work-up patients suspected of having thromboembolic disease.

Evaluation Studies as Topic↗
PubMed1981

A Kr-81m inhalation method for detection of absence of uniform ventilation in asthma.

In an attempt to compare inhalation methods in detecting abnormal patterns of ventilation, the following four techniques were applied in 12 asthmatic patients: spontaneous respiration with a Kr-81m gas-air mixture (SP technique); serial inhalation of a Kr-81m gas-air mixture from the level of residual volume to total lung capacity (VC technique); bolus inhalation of 10 ml or Kr-81m gas from the level of residual volume, followed by air, to total lung capacity (RV technique); bolus inhalation of 10 ml of Kr-81m gas from the level of functional residual capacity, followed by air, to total lung capacity (FRC technique). Before exercise, abnormalities were detected by the RV and FRC techniques, but no abnormalities were detected by SP and VC techniques. On studies done after exercise, the abnormalities were detected by all the described techniques. However, they were best demonstrated by the RV technique and shown least well by the VC method.

Adolescent↗
PubMed1982

The use of Kr-81m in ventilation imaging.

Radioactive gases are very useful in the study of pulmonary disorders because they allow an assessment of regional lung function. The most widely used radioactive gases are Xe-133 and, more recently, Kr-81m. This paper is a review of the physical characteristics of Kr-81m, its production from the parent Rb-81, the different methods to produce Rb-81, the different types of generators which can be used in hospitals, and the clinical applications of pulmonary ventilation imaging. The paper suggests that Kr-81m offers several advantages over previous methods that used Xe-133 due to its improved spatial resolution, its capacity to provide superimposable ventilation and perfusion images in multiple projections, and its total lung dose which is ten times lower than that of Xe-133.

Child↗
PubMed1984

Pulmonary ventilation and perfusion studies in lung cancer.

In 46 patients with bronchogenic carcinoma, the diagnostic significance of pulmonary ventilation images by the continuous inhalation of Kr-81m gas, which has an extremely short half life, was studied in comparison with pulmonary perfusion images with Tc-99m MAA. The data were processed using digital analysis techniques. There were 15 cases with discrepancies between ventilation and perfusion. The V/Q ratios of the affected lung among the 43 patients showed values above 1.2 in nine cases and below 0.8 in six cases. The Kr-81m ventilation and Tc-99m perfusion images were compared before and after radiation therapy in eight patients. It was possible to assess the therapeutic effect on regional ventilation and regional perfusion, which could not be evaluated by chest x-ray alone, under the same conditions of normal breathing.

Adenocarcinoma↗