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At least 379 records · Page 21Linked to original sources
PubMed1981

Krypton 81m ventilation scanning in chronic obstructive airways disease.

Ventilation and perfusion scans using 81Krm and 99Tcm-labelled macroaggregates have been studied in 60 patients with established chronic obstructive airways disease. Matched defects were found in all patients distributed throughout the lungs. Patients scanned during acute exacerbation frequently showed basal mismatched defects of ventilation (21 out of 30) and in a few follow-up scans showed resolution on treatment. Other patients also scanned in acute exacerbation showed unmatched defects of perfusion thought to represent pulmonary emboli. Poor correlation was found between scan defects assessed on a semiquantitative basis and conventional lung function tests.

Humans↗
PubMed1983

Assessment of right ventricular function and anatomy using peripheral vein infusion of krypton 81m.

A method for imaging the right side of the heart (atrium, ventricle and main pulmonary artery) and for assessment of RV systolic function (ejection fraction and ejection rate) is described. An ultra-short-lived isotope (81Krm) is continuously eluted in 5% dextrose and infused into an ante-cubital arm vein; standard multigated images are acquired using a gamma camera and commercially available software. Preliminary evaluation of the method in 55 subjects (20 with repaired tetralogy of Fallot, 14 with dilated cardiomyopathy and 21 normal volunteers) showed that the technical success rate was 100%; that RV boundaries free from LV overlap can be clearly visualised due to efficient exhalation of 81Krm through the lungs and that 81Krm measurements of RVEF are reproducible. The technique offers considerable potential for serial non-invasive assessment of RV function.

Cardiomyopathy, Hypertrophic↗
PubMed1985

A comparison of the economics of xenon 127, xenon 133 and krypton 81m for routine ventilation imaging of the lungs.

We have compared the cost of providing routine lung ventilation scintigraphy using 127Xe with other radioactive gases in 100 patients. The physical properties of 127Xe permit a logical imaging sequence where a ventilation study is only carried out if indicated by perfusion scintigraphy which is performed first. With 133Xe, all patients must be ventilated prospectively, or a preselection carried out based on radiographic appearances at the time of imaging. This results in a greater number of ventilation studies than with 127Xe. Despite the greater cost per study of 127Xe, the overall cost of providing a routine diagnostic service with this gas is no more than that of using 133Xe in selected patients. The cost of ventilating all patients prospectively with 133Xe is considerably greater than using 127Xe only when indicated by abnormal perfusion images. If ventilation imaging is to be available at all times, either isotope of xenon costs very much less than 81Krm. We conclude that 127Xe is the radiopharmaceutical of choice for routine lung ventilation scintigraphy.

Costs and Cost Analysis↗
PubMed1986

Clinical comparison of a new technetium 99m DTPA aerosol delivery system with krypton 81m.

We compared the clinical performance of a new 99Tcm DTPA aerosol delivery system with steady-state 81Krm gas in the diagnosis of pulmonary embolic disease. Forty patients had aerosol and 81Krm ventilation imaging followed by perfusion scintigraphy. The combined aerosol/perfusion images were compared with 81Krm/perfusion images for diagnostic equivalence. Aerosol image quality was also compared directly with 81Krm. Three-quarters of the patients who had segmental ventilation-perfusion (V/Q) mismatch on 81Krm/perfusion images also had mismatch on aerosol/perfusion images. Of those who had no mismatch on Kr/perfusion images, it was possible to rule out mismatch on aerosol/perfusion images in 80% of cases. Fifteen per cent of aerosol images were uninterpretable due to excess deposition in large airways. This problem was significantly more frequent in smokers than in non-smokers. The average delivery efficiency of the system was 2%, in terms of the proportion of loaded activity retained in the lungs. We conclude that the new device gives accurate clinical information in most cases, but is of less value for smokers.

Aerosols↗
PubMed1992

Can dynamic krypton-81m imaging separate regional ventilation and volume?

This study explores the assumption that 81mKr static images represent regional ventilation. Dynamic acquisition of 81mKr ventilation images permits creation of time-activity curves and the possible separation of the confounding influences of ventilation and volume. By using a two-compartment gas mixing lung phantom, the results demonstrate that both total and tidal 81mKr are closely related to regional ventilation. In 61 children and 15 adult volunteers, there was good agreement between fractional ventilation assessed by total and tidal 81mKr. The dynamic steady-state ventilation image can be analyzed to separate tidally exchanged and resident 81mKr. This may allow regional ventilation to be distinguished from regional volume.

Adolescent↗