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Biomedical subjects

L Pourcelot

Publications and source records attributed to L Pourcelot.

At least 145 records · Page 8Linked to original sources
PubMed1980

[Ultrasonographic examination of the breast: current use and perspectives (author's transl)].

Ultrasonographic examinations were conducted in one hundred patients with breast tumors (fifty cancers, twenty-five fibro-adenomas, and twenty-five cysts) using a manual apparatus and a 5 megahertz probe. Cysts are easily, diagnosed by ultrasonography if they are larger than 5 mm in diameter, but an equally effective result can be obtained by needle puncture. Results are less valid in fibro-adenomas (3 false positives), but this method is feasible in young women with radio-opaque breasts. Diagnosis by ultrasonography of breast cancers again depends on the size of the tumor (40 p. cent of false negatives in TI cases). The authors presently employ ultrasonography only for the diagnosis of solid, apparently non-malignant tumors, in young women (under 30 years) in whom mammography is ineffective, and for non-palpable radiologically detected opacities. New ultrasonography technics should enable improved results to be obtained when using non-invasive procedures for the diagnosis of breast tumors.

Adenofibroma↗
PubMed1978

The contribution of nuclear medicine and ultrasounds in cardiac surgery.

The constant progress in surgical techniques during the last few years have prepared the way for important developments in the field of noninvasive cardiac exploration. Their non-traumatic character, appreciable in diagnostic and preoperative examinations, become indipensable whenever there is a need to repeat the examination in order to evaluate the effects of a treatment or to monitor progress both in the short and long term. In order that such methods be adopted in cardiac surgery it is important that not only must they be without risk but also that the results obtained be clearly presented, if possible in the form of images, and allow a quantitative interpretation. It is necessary also that the results can be justified both by clinical experience and also by comparison with other examinations. No procedure, not even radiologic, can at the same time explore the myocardium and its perfusion, the central circulation and the cardiac haemodynamics. By reason of their respective principles, radioisotopic methods and ultrasounds tackle cardiac problems in different ways and facilitate, by appropriate choice of methods, the selection of one diagnostic response from among several. This paper contains first of all, a resume of the principal nuclear and ultrasonic techniques used together with their basic principles. Next we try to show how these non-invasive techniques, most with dynamic imaging, can assist cardiac surgery. For this, we successively look at the different pathologies, working from the exterior (pericardium) towards the interior (intracardiac structures and central circulation) and covering the different aspects of the myocardial pathology. In each case the mutual contributions of physical techniques is specified as well as the preference for either isotopic or ultrasonic methods.

Angiocardiography↗
PubMedDate not supplied

Doppler assessment of hemodynamic changes after hemodilution in retinal vein occlusion.

PURPOSE: We assessed the usefulness of color Doppler imaging and spectral analysis in monitoring the effect of isovolemic hemodilution on retinal vein occlusion. METHODS: Color Doppler imaging was used to measure the systolic and diastolic blood flow velocities and the resistance index (RI) in the central retinal artery and the maximum and minimum blood flow velocities in the central retinal vein of affected eyes and contralateral unaffected eyes before and 1 day after isovolemic hemodilution in 70 adults (40 men and 30 women; mean age, 62.4 +/- 13.7 years) who presented with retinal vein occlusion. RESULTS: With hemodilution, the hematocrit value was decreased from 41.8 +/- 3.0 to 33.0 +/- 3.0. In central retinal vein occlusion, the pretreatment arterial and venous flow velocities of affected eyes were significantly lower than those of unaffected eyes. After hemodilution in eyes affected by ischemic occlusion, a significant improvement in the RI in the central retinal artery was observed without changes in venous flow velocity. After hemodilution in eyes affected by non-ischemic occlusion, a significant increase in maximal venous flow velocity only was noted. In branch retinal vein occlusion, no significant difference was observed in the RI between affected and unaffected eyes. After hemodilution, an improvement in RI was noted only for affected eyes. CONCLUSIONS: The present results confirm the potential value of Doppler analysis in monitoring the impact of hemodilution on arterial and venous velocity in patients with central retinal vein occlusion.

Adult↗
PubMedDate not supplied

Doppler study of fasting and postprandial resistance indices in the superior mesenteric artery in healthy subjects and patients with cirrhosis.

PURPOSE: We assessed the resistance index (RI) in the superior mesenteric artery under fasting and postprandial conditions in healthy subjects and in patients with cirrhosis to determine whether the amount of change in the RI reflects the presence or severity of liver dysfunction. METHODS: Fifteen subjects with normal livers and 27 patients with cirrhosis underwent Doppler sonography of the superior mesenteric artery before and after ingesting a standard meal. The RI at baseline (fasting state) and the postprandial RI were compared between the 2 groups. The fasting RIs and post postprandial RIs changes in cirrhotic patients were correlated with the severity of disease. RESULTS: No difference was found between the baseline RIs in healthy (RI = 0.85) and cirrhotic subjects (RI = 0.84), nor was there a difference in baseline RIs between subgroups of cirrhotic patients according to the severity of liver disease. The RI decreased significantly (p < 0.05) after the meal in both the healthy (13%) and cirrhotic (8%) subjects, but the postprandial decrease was significantly less pronounced (p < 0.05) in cirrhotic patients than in healthy subjects. Among cirrhotic patients, there was no correlation between the postprandial decrease of the RI and severity of liver disease. CONCLUSIONS: The marked decrease in the postprandial RI in the SMA in healthy subjects is generally not seen in patients with cirrhosis, and changes in the postprandial RI do not reliably predict the severity of liver dysfunction.

Adult↗
PubMedDate not supplied

Diffusion imaging with a multi-echo MISSTEC sequence.

An imaging method is presented to measure the water-diffusion coefficient. The sequence (MISSTEC) uses the simultaneous acquisition of a spin echo and several stimulated echoes with the same intensity except for diffusion weighting. The optimal number of stimulated echoes was calculated to minimize the diffusion coefficient error (D). D values obtained in vitro and in vivo were in good agreement with those from the spin-echo sequence (IntraVoxel Incoherent Motion [IVIM] method). The total acquisition time is half that of the classic IVIM method.

Brain↗
PubMedDate not supplied

[Ultrasonographic study of the cerebral circulation in elderly subjects (author's transl)].

The amount of diastolic blood flow in the carotid and vertebral axes determines the tolerance capacity of the cerebral circulation to physiological variations. In the elderly subject this "circulatory reserve" is modified by increases in cerebral circulation resistance, but also by various common cardiac or blood pressure disorders. Furthermore, direct visualization of the atheromatous plaques and calcifications in the vessel walls by ultrasonography can reveal lesions that have no clinical expression.

Aged↗