Search PubMed⌕ Search

Biomedical subjects

J D Picard

Publications and source records attributed to J D Picard.

At least 19 recordsLinked to original sources
PubMed2000

[Positron emission tomography in tumor pathology].

After a brief reminder concerning the PET technique and use of FDG, the author sets out to summarize the results of numerous PET centers in the world and in more detail, results of European units he visited. Leaving neurology and cardiology out, the most important works are dealing with tumoral pathology. The sensitivity of the technique is high for localizing tumoral tissue, evaluating lymphatic spread and detecting metastases. On the contrary, specificity is low as non tumoral lesions, especially inflammatory lesions, tuberculosis may pick up FDG though with less intensity. PET contributes to precise staging TNM of cancer, especially in case of pulmonary neoplasms. Results of clinical evaluation of bronchial carcinoma are presented. Other research programs show similar positive results for the staging of digestive tract neoplasm, primary or metastatic lymph node diseases, metastases from a quiescent, unknown primary tumor. The fact that the number of PET units is small explains the relatively poor dissemination of the method. It is rather obvious that the limitation of the number of PET units is due to economic reasons. Since 1990, many scientific evaluations of this technique conclude positively on PET's future. As it essentially is a functional method, the future developments of PET will largely depend on the discovery of new tracers.

Europe↗
PubMed2000

[Arteriography, endoscopy and periscopy: simultaneous digital imaging].

The author reports his personal, limited experience as well as a literature review concerning first results of a simultaneous study of the blood vessels obtained in a similar approach to conventional angiography, but using a digital approach of the vascular lumen, the normal or pathological endothelium, the adventice and/or the perivascular environment. A static and morphologic iconography aims to demonstrate the potential of this imaging approach in the future, especially knowing that those images may be combined to kinetic and/or functional images of the blood circulation.

Angiography↗
PubMed1999

[Virtual endoscopy].

After a brief definition of Virtual Endoscopy (VE), the authors, by a personal experience and literature analysis, present the results of this new method in several applications: tracheo-bronchial tree, vessels, colon, bladder, central nervous system; patients were referred by standard endoscopy, advantages and limits were studied. We underline the atraumatic feature of VE and superiority of fibroscopy. Terminology is assessed. To compare two methods, one recent, is not actually specially justified. "VE" development is an undeniably interesting challenge for standard endoscopy. Is is absolutely conceivable that in the next future, an important number of purely diagnostic exams will be carried on by virtual technics (J. F Rey).

Endoscopy↗
PubMed1998

[History of mammography].

The History of mammography began in 1913, when a Berliner surgeon, A. Salomon realized a roentgeno-histological study on 3,000 mastectomies. This work is the basis of mammography. Until 1938, few articles were published but were of little help to mammography. From 1947 to 1970, the second period brought the results of roentgenologic and clinical correlation. R. Leborgne was the first accountable for the wide development of this method. Since 1951, many American and European radiologists brought their contribution. Ch. Gros is the best known. He gave this technique an acknowledgment throughout the world for the diagnosis of breast diseases. Since 1970, the third period emphasizes the value of mammography as a technique for detection of breast cancer. Some "Screening working groups" are being set up. The problem is mainly economical.

Adult↗
PubMed1997

[Imaging venous and lymphatic valves].

Venous and lymphatic valves have many common characteristics which can be studied with various direct and indirect methods. The indirect methods only recognize functional disorders provoked by valve damage. A disruption in the valve system produces venous or lymphatic stasis whose clinical manifestation depends on the localization and the extent of the valve damage. Blockade is another, generally less important mechanism leading to stasis. Valve insufficiency and blockade are often associated. The only point distinguishing between venous and lymphatic valve damage is the site. The peripheral, usually in the limbs, or terminal veins, for example in the heart, are usually involved while for the lymphatic vessels, the entire system may be involved including deep organs where visceral lymph stasis is observed. The general notions lead to indications for different imaging techniques. Functional explorations include ultrasound-Doppler, dynamic phlebography, isotopic lymphography and methylene blue test. Some clinical examples are presented describing the possibilities of these methods. The morphology of the valves is usually studied with phlebography and perhaps in the near future with magnetic resonance angiography. Endoscopy is the ideal method but is limited by the assessible venous territories. Search for the cause of blockade relies on computed tomography and magnetic resonance imaging which have progressively replaced lymphography and phlebography. In conclusion, the methods presented here, whether used in combination, are often in direct competition. They are all relatively aggressive examinations with a high cost. It is thus important to carefully choose the method according to the clinical indication and expected performance.

Humans↗
PubMed1996

[Bertha Röntgen or the transparency of the hand].

It is to Wilhelm Conrad Röntgen, the first elected "radiologist" of our Academy and the first Nobel Prize winner in physics, that we owe the transparency of the hand. We celebrate today the centenary of the great scientific discovery which was to revolutionize the diagnosis, and thereby the treatment, of a large number of illnesses the discovery of X-rays. It would be unjust not to link the name of this scientist with that of his wife, Bertha, who, ignorant of the dangers of all "novel medical inventions" volunteered her own hand for his research experiments: the hand which was to bring to the world tangible proof of this remarkable discovery. To a lesser degree, but nonetheless essential, we acknowledge, albeit not in exhaustive detail, all the progress made by the work of pioneers using this new investigative technique. So let us now return to the hand:--a body part which it was easy to immobilize, remembering that in those days a single radiographic exposure took up to an hour to obtain,--we will consider the immortalised hand of Bertha Röntgen,---to whom this address is dedicated,---and its radiographic exposures which allow us to appreciate the advances and to perceive the limitations of this technique. They also enable us better to envisage future investigative approaches whereby a deeper knowledge of the human body may be acquired. We note that compared with the histopathological sciences, imaging is not specific. Numerous microscopic structures, in particular neurological and vascular ones, are still insufficiently well visualised and the transmission pathways between the hand and the central nervous system deserve better characterisation. Current, research programmes are attempting to overcome these limitation of modern imaging. All the experience gained in studying the transparency of the hand, as we have discussed, is applicable to every part of the human anatomy. To credit: Röntgen's discovery with all its originality, we could say that the hand was to radiology what the brain was to CT and MRI scanning: an exceptional victory is rendering the human body transparent.

Female↗
PubMed1996

[Forensic medical implications of vascular punctures and catheterization and radiologic procedures with diagnostic or therapeutic purpose].

Whatever the aim of the procedure, puncture of a vessel can lead to local complications. Access to the artery carries a risk of hemorrhage, occlusion, stenosis, arteriovenous fistulization or pseudo-aneurysm. The same types of complications can occur in veins. Other complications include skin necrosis due to extravasation of the contrast medium, perforation of the superior vena cava after insertion of an infusion catheter and the risk of pericardial effusion. General complications occur immediately, usually caused by contrast media, or late. There are different examples of secondary legal procedures following punctures involving, with the exception of radiology cases, intraarterial injection at the elbow, perforation of the right atrium by a jugular catheter and acute ischemia of the foot after catheterization of the pedial artery. Legal procedures after radiological procedures were discussed in more detail. The personal experience of the authors and others concerns accidents occurring after arteriography, angioplasty or embolization. Finally, two legal cases after treatment for impotency are analyzed. We focus on a certain number of rules on patient information, preangiography consultation, participation of an anesthetist, careful post-operative follow-up and operation report. Finally, the possibility of radiation-induced arteriopathy is demonstrated by one case reported here.

Angiography↗
PubMed1995

[The future of angiography].

Recent trends in echo-Döppler, heli CT and magnetic resonance angiography (MRA) together, have brought about a very significant drop in conventional X-ray angiography indications. Diagnosis of arterial, venous and lymphatic pathology is studied in various vascular anatomic areas. Based on these results, an attempt is made to forecast X-ray angiography future and its importance with respect to other imaging modalities. It is thought that the remaining role of angiography will be very poor in vascular pathology diagnosis. Still, its importance as endovascular treatment will remain vital. This change will cause a drastic shift among clinical activities of the various vascular diagnosticians and vascular specialist populations.

Angiography↗
PubMed1990

[Current status of research of a lymphatic system in the nervous system: initial trials with cerebral lymphography].

After having recognized the existence of post-mortem intra-cerebral circulation of a coloring substance with lymphatic resorption, the author is continuing his research by injecting a product sharing the same characteristics: Iotrolan. Brain X-rays show brain circulation from the cortex to the ventricular cavities and from the spinal cord to the bulbar area and to the cerebellum. One question deserves to be asked: what is this circulation?

Animals↗
PubMed1990

[In search of the lymphatic system of the central nervous system].

Lymphatic flow in the brains and lymphatic vessels in the meninges are recognized through the intra-cerebral injection of a dye specific to the lymphatic system. The confluence of these two components can only be at the level of the cerebro spinal fluid (CSF), which lends support to the hypothesis that the CSF itself constitutes the lymph of the nervous system. The authors report the results of a study based on a necropsic investigation and an experimental animal model, contributing new facts in favor of this hypothesis. For a certain number of inflammatory diseases of the central nervous system (CNS) when the initial phase is still limited to the brain or to the spinal chord tissues, it is usually asymptomatic; only when it reaches the meninges, that clinical symptoms be seen: this can be explained by the presence of such lymphatic circulatory system. Stasis of the cerebral lymphatic circulation, should be regarded as a new etiologic factor in the onset of brain oedemas. This concept, already taken into account by some investigators, deserves consideration in the study of most CNS diseases.

Animals↗
PubMed1989

[Pitfalls in phlebography].

Despite the progress in functional investigation procedures, phlebography remains the standard test in venous disease of the lower extremities. The development of better quality contrast media has significantly improved patients tolerance. After a review of the regular, routine procedure, the authors stress the technic's pitfalls. Uncomplicated pitfalls are air bubbles, Venturi's effect, venous malformations, and superimposed venous axes or gases. This type of problems is easily circumvented. Flow images caused by confluent axes of high-flow veins (internal iliac veins, renal veins) or layer courants (gutter effect) are presented as a reminder. Compression images are often more treacherous: related to normal veins: compression of left iliac vein by aortic junction; of inferior vena cava by enlarged aorta or by osteophyte; tourniquet too low, iliac vein compressed by a dilated bladder; or compression due to intramuscular hematoma,... related to pathological veins: to be mentioned are bridle-caused obstruction of the popliteal vein (Klippel-Trénaunay syndrome), and retroperitoneal fibrosis. Although the present description of phlebography-related pitfalls is neither new, nor exhaustive, it should be reconsidered, as phlebography of the lower limbs, while being currently better tolerated, is still an update technic that needs to be rendered more reliable.

Constriction↗