Nuclear medicine communications
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A series of 14 patients with heart failure due to coronary artery disease and impaired left ventricular function underwent radionuclide ventriculography with simultaneous thermodilution measurement of cardiac output by pulmonary artery catheter on two occasions (m1, m2) separated by 6 weeks in order to determine the reproducibility of haemodynamic and left ventricular volume measurements at rest and during supine bicycle exercise. The patients were in NYHA grade II or III and had baseline left ventricular ejection fractions below 40%. Derived haemodynamic variables were calculated from the thermodilution cardiac output and from the radionuclide ejection fraction as follows: stroke volume = thermodilution cardiac output/heart rate; left ventricular end-diastolic volume = stroke volume/ejection fraction; left ventricular end-systolic volume = end-diastolic volume - stroke volume. ⋯ By contrast, the reproducibility of the pulmonary capillary wedge pressure measurements was poor, as reflected by a PD value of 14 +/- 51% for exercise pulmonary capillary pressure. Combining radionuclide ventriculography and the thermodilution measurement of cardiac output is useful for measuring left ventricular volume at rest and during exercise in patients with heart failure. This minimally invasive technique allows for a comprehensive assessment of left ventricular performance and appears to be particularly suited for assessing the effects of therapeutic interventions aimed at minimizing the progressive left ventricular enlargement in heart failure.
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Clinical Trial Controlled Clinical Trial
Quantification of extracorporeal white cell and platelet deposition in cardiopulmonary bypass: comparison of membrane and bubble oxygenators.
Cardiopulmonary bypass is known to activate both white cells and platelets. The aim of this study was to investigate whether the use of bubble and membrane oxygenators results in different degrees of deposition in the filter and oxygenator of the bypass circuit. Dual-isotope imaging techniques were employed, with white cells labelled with 99Tcm and platelets with 111In, and with subsequent imaging of the filters and oxygenators on a gamma camera fitted with a medium-energy, parallel-hole collimator, relative to a known standard. ⋯ The striking feature of the data is the non-normal distribution of the deposition in both types of oxygenator. This study demonstrated that both white cell and platelet deposition in the cardiopulmonary bypass circuit can be quantified using radiolabelled cells. No differences in oxygenator or filter deposition were found in patients randomly allocated to membrane or bubble oxygenation.
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Clinical Trial Controlled Clinical Trial
The effect of coffee on gastric emptying.
The effect of coffee on gastric emptying was addressed in a scintigraphic liquid-phase gastric emptying study in patients with non-ulcer dyspepsia. Ninety-three subjects (56 males, 37 females; mean age 40 years, range 17-77 years) diagnosed as having non-ulcer dyspepsia were enrolled in the study. The baseline study was to drink 500 ml of 5% glucose water and the coffee study was to drink 500 ml of 5% glucose water containing 4 g of regular instant coffee. ⋯ However, 68 (73.2%) subjects showed accelerated emptying (-14.8 +/- 19.5 min), while 25 (26.8%) subjects showed delayed emptying (5.9 +/- 4.5 min) after ingestion of coffee. There was no significant difference in the change in gastric emptying with coffee in duplicate measurements from the 15 subjects who had two coffee studies (P = 0.082). We conclude that coffee accelerates liquid-phase gastric emptying in the majority of patients with non-ulcer dyspepsia.
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Air contamination levels arising from lung aerosol ventilation studies have previously been monitored [1]. Residence time in the room used for ventilation was perceived to be an important factor in dose received. This study was designed to assess air contamination levels when ventilation and imaging are carried out in the same room. ⋯ Aerosol ventilation in the gamma camera room does not constitute a significant radiation hazard to staff. Patient compliance is an important factor in minimizing doses. Clear instructions and practice are a vital part of the procedure.
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Comparative Study
Is computer-aided interpretation of 99Tcm-HMPAO leukocyte scans better than the naked eye?
In order to compare visual interpretation of inflammation detected by leukocyte scintigraphy with that of different computer-aided quantification methods, 34 patients (25 with ulcerative colitis and 9 with endoscopically verified non-inflamed colonic mucosa), were investigated using 99Tcm-hexamethylpropyleneamine oxime (99Tcm-HMPAO) leukocyte scintigraphy and colonoscopy with biopsies. Scintigrams were obtained 45 min and 4 h after the injection of labelled cells. Computer-generated grading of seven colon segments using four different methods was performed on each scintigram for each patient. ⋯ Agreement assessed using kappa statistics was 0.54 at 45 min (P < 0.001). Separate data concerning the presence/absence of active inflammation showed a high kappa value (0.74, P < 0.001). Our results showed that a simple scintigraphic scoring system based on assessment using the human eye reflects colonic inflammation at least as well as computer-aided grading, and that highly correlated results can be achieved between different investigators.