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F Cavailloles

Publications and source records attributed to F Cavailloles.

18 recordsLinked to original sources
PubMed1991

Radionuclide evaluation of cardiac function during sleep in children with bronchopulmonary dysplasia.

The influence of sleep on cardiac function in severe bronchopulmonary dysplasia was assessed in five children 1.5 to 5 years of age. Left and right ventricular ejection fractions (LVEF and RVEF) were investigated by equilibrium radionuclide ventriculography in five children undergoing polygraphic monitoring during the different states of alertness: wakefulness, nonrapid eye movement sleep, and rapid eye movement sleep. Intraobserver and interobserver LVEF and RVEF measurement reproducibility was high. During quiet, supine wakefulness, LVEF was normal, but RVEF was low. During sleep, a decrease in both LVEF and RVEF, expressed as a percentage of the awake value, was marked in the two children with the most nocturnal desaturation and longest duration of paradoxic rib cage motion during inspiration. It is concluded that radionuclide ventriculography can be easily performed during sleep in children and can provide useful information regarding right ventricular function during sleep in children with severe bronchopulmonary dysplasia.

Bronchopulmonary Dysplasia↗
PubMed1987

Automated processing of first-pass radionuclide angiocardiography by factor analysis of dynamic structures.

A method for automatic processing of cardiac first-pass radionuclide study is presented. This technique, factor analysis of dynamic structures (FADS) provides an automatic separation of anatomical structures according to their different temporal behaviour, even if they are superimposed. FADS has been applied to 76 studies. A description of factor patterns obtained in various pathological categories is presented. FADS provides easy diagnosis of shunts and tricuspid insufficiency. Quantitative information derived from the factors (cardiac output and mean transit time) were compared to those obtained by the region of interest method. Using FADS, a higher correlation with cardiac catheterization was found for cardiac output calculation. Thus compared to the ROI method, FADS presents obvious advantages: a good separation of overlapping cardiac chambers is obtained; this operator independant method provides more objective and reproducible results. A number of parameters of the cardio-pulmonary function can be assessed by first-pass radionuclide angiocardiography (RNA) [1,2]. Usually, they are calculated using time-activity curves (TAC) from regions of interest (ROI) drawn on the cardiac chambers and the lungs. This method has two main drawbacks: (1) the lack of inter and intra-observers reproducibility; (2) the problem of crosstalk which affects the evaluation of the cardio-pulmonary performance. The crosstalk on planar imaging is due to anatomical superimposition of the cardiac chambers and lungs. The activity measured in any ROI is the sum of the activity in several organs and 'decontamination' of the TAC cannot easily be performed using the ROI method [3]. Factor analysis of dynamic structures (FADS) [4,5] can solve the two problems mentioned above. It provides an automatic separation of anatomical structures according to their different temporal behaviour, even if they are superimposed. The resulting factors are estimates of the time evolution of the activity in each structure (underlying physiological components), and the associated factor images are estimates of the spatial distribution of each factor. The aim of this study was to assess the reliability of FADS in first pass RNA and compare the results to those obtained by the ROI method which is generally considered as the routine procedure.

Angiocardiography↗
PubMed1985

[Tomodensitometry and cerebral scintigraphy. Respective indications].

The comparative values of computerized tomography and radionuclide scan for the diagnosis of brain lesions were assessed on a series of 550 patients. A number of indications for each of these two methods have emerged from our results and from those found in the literature. The biases encountered in this type of study are discussed, and a "decision-making flow-chart" is proposed. The procedure of choice is computerized tomography in patients with suspected tumour or intracerebral haematoma, and radionuclide scan in those with suspected subdural haematoma or superficial cerebrovascular disease. The usefulness of clinical examination to determine precisely which of these two methods should be used cannot be overstressed.

Brain↗
PubMed1984

Factor analysis in gated cardiac studies.

Factor analysis of dynamic structures (FADS) can automatically provide "physiological" factors related to anatomical structures that have different temporal behavior, even if these structures overlap; it also yields images corresponding to the factors' spatial distributions. In normal patients, two significant cardiac factors, corresponding to the atria and the ventricles, may be extracted. A third significant factor can be obtained when additional dynamic structures exist. However, the method does not provide an estimate of the background. It becomes part of the factors, but it does not modify their shapes. FADS has been applied to 45 gated cardiac studies. Results obtained by FADS were compared with those obtained from the amplitude and the phase of first-harmonic Fourier analysis (FA). The joint results were compared with the final diagnosis, established by real-time echocardiography and/or ventriculography. In normal patients, good agreement was obtained between the two approaches. On the whole set of patients, FADS was significantly better than FA (by sign test: p less than 5%).

Atrial Function↗
PubMed1983

Thallium uptake in fasted and nonfasted rats.

Thallium uptake was studied in selected organs in two groups of rats: fasted and nonfasted. A significant increase in thallium uptake was found in the stomach and the small intestine after eating while a significant decrease was found in the lung.

Animals↗
PubMed1983

Bone scintigraphy in Perthes disease.

After intravenous injection of 99mTc methyldiphosphonate, 190 hip bone scans were performed on 103 children. In 64 children with Perthes disease, 61 of 71 hips (86%) showed abnormal scintigraphy. There were no false positives. In other hip disorders, the scan was never considered to simulate Perthes disease. There were 36 children with acute synovitis and three with Meyer's dysplasia. The sensitivity was 97%, suggesting that this test should be used more frequently in the early assessment of hip pain in the young child, before the appearance of characteristic radiographic abnormalities. This test is also valuable for follow-up of the disease because of its prognostic value--the bone scan becomes normal far earlier than the radiograph. The progressive normalization of the scan may help determine when the child can begin weight-bearing.

Adolescent↗
PubMed1982

Bone scintigraphy in the diagnosis and follow up of Perthes' disease.

One hundred and thirty three children were studied (a total of 218 scintigrams) after IV injection of 100 microCi/kg 99Tc-MDP. Of 64 pathological hips (6 being bilateral), 52 were judged typically abnormal, 8 without initial radiological evidence. Of the rest, 8 were considered doubtful and 4 normal. No scan was considered typical of Perthes' disease in other hip disorders. The resulting figure of the sensitivity was 94%, for specificity 97%, for positive predictive value 97%, and for negative predictive value 95%. It is more difficult to assess the value of bone scintigraphy in the follow up of these patients. The disappearance of uptake defect in the femoral head may be a good index and occurs earlier than the normalization of the radiographs. On the other hand, the significance of the neighbouring region of increased uptake is difficult to assess although related to revascularization and reconstruction. The evolution of the disease does not seem to be correlated with the localization and the intensity of these regions in a straightforward manner.

Adolescent↗
PubMed1980

Performance characteristics of a commercial ECG gate.

A commercial ECG gate was tested to evaluate its ability to predict accurately the time of end-systole. The predicted times followed the manufacturer's specifications quite well. These times were compared with the actual times of end-systole as determined by computer-derived left-ventricular time-activity curves using Tc-99m-labeled red blood cells. Although there was moderate scatter, the predicted times of end-systole correlated well with the actual times (n = 59, r = 0.829). If the left-ventricular ejection fraction was calculated using the predicted time of end-systole, the error would be 0.03, or less, for 95% of the subjects.

Cardiac Output↗
PubMed1978

[Extra-intracranial arterial bypasses. Evaluation of their permeability by use of the Doppler effect].

40 temporo-sylvian anastomoses were controlled using Doppler ultrasonic examination. The results are compared to post-operative arteriograms. The Doppler examination has proved to be highly accurate when compared to contrast arteriography in the survey of extra-intracranial anastomosis. This non invasive procedure can easily be repeated. However the size of the revascularized area cannot be estimated. The simultaneous isotopic studies of regional cerebral blood flow could provide a means of quantifying the results of the anastomoses.

Carotid Artery, External↗