[Effect of cardiac rate on the index of feto-placental circulatory resistance]. / Effet de la fréquence cardiaque sur l'index de résistance circulatoire foeto-placentaire.

Variations of the fetal heart rate in normal or pathological fetuses may induce significant changes of the Doppler indices widely used for the evaluation and the assessment of the placental or cerebral resistances. In case of a low heart rate (120/mn for example), the end diastolic amplitude will be weaker than in case of a heart rate of high frequency (160/mn). This phenomena may explain the great scattering of the normal values of the Doppler indices and the relatively poor sensitivity of this parameter. We tried to minimize the effect of the heart rate on the evaluation of the doppler indices by two methods. Firstly by measuring on the maximum frequency curve the end diastolic frequency for a standard heart rate of 140/mn and the corresponding Doppler index (R'140). Secondly by using a formula giving directly (from the R value on the trace) the value of the index (R"140) for a heart rate of 140/mn. The diagrams of the indices (R'140 R"140) calculated for a standard frequency of 140/mn (on normal and pathological fetuses) show a greater dispersion than the R indices directly measured on the Doppler waveform. Therefore, the sensitivity and the specificity of the Doppler method are reduced. Finally, we conclude that the haemodynamic parameters in the different vascular areas of the fetus can adapt to the heart rate except for very strong abnormalities of the heart rate as it is the case in atrio ventricular blocks for instance. Out of these cases, it seems that the normalization of the index by the heart rate does not improve the accuracy of the doppler indices.

[Tentative classification of the ultrasound symptomatology of the prostate by an anatomo-ultrasonic comparison of 34 cases]. / Tentative de classification de la sémiologie échographique de la prostate par confrontation anatomo-ultrasonique de trente-quatre cas.

Ultrasound and histological sections were taken of 34 prostate units removed from fresh cadavers. Ultrasonography seems to raise more problems than it solves; only 73% of the normal prostates were homogeneous under ultrasound. Ultrasonography visualized nodular structures requiring biopsy in 71% of the cases of prostatic adenoma. There were too few cases of malignant tumors in the sample to warrant a conclusion. They were highly evolved. Ultrasonography gave strong grounds for suspicion, but they could be easily diagnosed clinically.

[Transcutaneous measurement of blood flow in arteriovenous fistulae caused by hemodialysis using Doppler ultrasound]. / Mesure transcutanée du débit dans les fistules artério-veineuses d'hémodialyse par échographie-Doppler.

Blood flow measurement in arterio-venous fistulae can be performed with a duplex ultrasound system which combines echography and C. W. Doppler. This method is very useful to follow up the patency of the fistulae and his consequence on the cardiac function. The exploration consists in two steps: a qualitative study of the Doppler spectrum to detect a possible decrease of the arterial diastole flow which traduce a severe stenosis; the evaluation of the blood flow in ml/min. The blood flow in ml/mn is a good parameter for the follow-up of the fistulae; moreover in case of high blood flow values, it is very useful to guide the surgical therapy.