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F Joffre

Publications and source records attributed to F Joffre.

At least 55 records · Page 3Linked to original sources
PubMed1999

In vivo tissue extracellular volume fraction measurement by dynamic spin-lattice MRI relaxometry: application to the characterization of muscle fiber types.

RATIONALE AND OBJECTIVES: The extracellular volume fraction (v) was estimated in leg rabbit muscles by MRI dynamic longitudinal relaxation rate (R1) relaxometry to distinguish between slow- and fast-twitch muscle fiber types. METHOD: The extracellular volume fraction was calculated from the dynamic increase of the longitudinal relaxation rate after intravenous administration of a gadolinium (Gd-DTPA) contrast bolus, assuming a biexponential plasma concentration model. RESULTS: It has been shown that the extracellular volume fraction increases with the slow fiber content (oxidative type I); the maximal value (v = 0.186+/-0,018) was obtained in pure slow-twitch muscle fiber (100% type I). CONCLUSION: NMR extracellular volume estimates closely agree with those obtained using the more classic invasive isotopic method (99mTc-DTPA) carried out on the same rabbit strain and with data reported in the literature. The method has potential applications to characterize the pathophysiologic status of tissues. It is also applicable to a wide range of tissues and pathologies, in particular for the characterization of malignant tissues and their response to therapies.

Animals↗
PubMed1999

MRI dosimetry: a fast quantitative MRI method to determine 3D absorbed dose distributions.

RATIONALE AND OBJECTIVES: Magnetic resonance imaging (MRI) techniques seem to be very promising for 3D dosimetry studies, but long imaging acquisition time limits their use. A new fast T1 mapping protocol, easy to implement on a conventional MR imager, has been used to determine dose distributions on Fricke gels. METHODS: The method has been tested on manganese chloride (MnCl2) doped ferrous gelatin gels. The T1 measuring times range from 1 minute 40 seconds to 3 minutes 30 seconds for a 256x256 matrix image. RESULTS: The two- and three-dimensional profiles agree with those obtained with conventional dosimetry techniques (ion chambers). The precision and the spatial resolution principally depend on the signal-to-noise ratio of the used imaging RF coil. For example, for a surface coil, the accuracy is about 2.5% with a 1.56 mm spatial resolution. CONCLUSION: These preliminary results support the feasibility of the proposed technique for accurate MRI dosimetry studies and also have potential for various clinical quantitative MRI applications.

Gels↗
PubMed1999

[Diagnosis and endovascular treatment of thoracic aortic diseases].

Recent years have seen the emergence of non-invasive imaging techniques for the morphological assessment of the thoracic aorta. This evolution results in an important reduction of the role of diagnostic angiography. Simultaneously, thanks to a tremendous technologic development, endovascular treatment techniques concern nowadays some pathologic conditions of the descending aorta. A number of reports using a variety of devices have been published in the literature concerning the treatment of dissection and aortic aneurysm. Based on mid-term results, endoluminal repair with use of stent-grafts is a feasible and safe alternative to surgery with a low rate of morbidity and mortality. In type B dissections with end-organ involvement, interventional radiology can be used either to fenestrate the flap or to stent the flap in branch arteries. Proper selection of patients by non-invasive imaging is fundamental for successful endoluminal treatment. However, there is still major concern with respect to long term results of these new treatments.

Adult↗
PubMed1998

Endovascular stents in arterial injury after radiotherapy.

We evaluated preliminary success and patency of stenting for the treatment of radiation-induced arterial diseases. Thirteen stents were placed in 8 patients to treat occlusion (n = 3), aneurysm (n = 1), residual stenosis (n = 2), multiple stenoses (n = 1), and delayed restenosis after previous balloon angioplasty (n = 1). Interventional procedure was successfully performed in 8 patients for their arterial lesions after radiotherapy. Six patients underwent interventional procedure once or twice. Two patients underwent PTA 4 times. Five of these patients demonstrated primary patency with relief of clinical symptoms with a mean follow-up of 2 years (range: 8-60 months). Clinical improvement was noted in the other patients. Our results suggest that stent placement by single or multiple techniques may have immediate effect on arterial lesions caused by radiation and can be considered as a therapeutic option of choice in these cases.

Adult↗
PubMed1998

Endovascular retrieval of two migrated venous stents by means of balloon catheters.

The usefulness of vascular stenting was demonstrated in both arterial and venous applications to restore patency and improve suboptimal results after percutaneous transluminal angioplasty. Dislodgment of venous stents with an embolization into the right cavities or the pulmonary artery, however, is one of the most feared complications of this procedure. Percutaneous removal of these migrated stents is an appealing method of replacing more invasive operative intervention with cardiopulmonary bypass, which may be very hazardous in these often severely ill patients. We describe the cases of two patients with stents that migrated into the right ventricle and the pulmonary artery. In one patient, we were able to successfully remove these stents by using an angioplasty balloon with an operative extraction from the iliac vein, thereby obviating the need for a major operative procedure.

Adult↗
PubMed1998

Modular component separation and reperfusion of abdominal aortic aneurysm sac after endovascular repair of the abdominal aortic aneurysm: a case report.

Transluminal placement of a stent graft in patients with an abdominal aortic aneurysm is a new endovascular technique that offers a potentially less invasive and less risky alternative to open surgery. Complications after stent graft placement are not infrequent, but in most cases secondary endovascular intervention is successful. We describe a late major leak in the aneurysmal sac caused by a distal migration of the iliac limb of a bifurcated graft. This late complication was successfully treated by covered stent placement, excluding and thrombosing completely the reformed aneurysm.

Aged↗
PubMed1997

Histopathologic analysis of transjugular intrahepatic portosystemic shunts.

This prospective study was undertaken in 17 patients treated with 22 transjugular intrahepatic portosystemic shunt (TIPS) procedures and aimed to evaluate the nature and causes of short- and long-term shunt abnormalities. Specimens were collected after autopsy in 6 patients and after liver transplantation in 11 patients; the time from shunting ranging from 4 to 385 days. During the first 2 weeks the shunt surface was covered by poorly organized fibrin platelet clots that were mixed with inflammatory and red blood cells. Thereafter, a pseudointima developed, initially made of loose granulation tissue that was formed by edema, myofibroblasts, neo-capillaries, collagen fibers, and inflammatory cells. This pseudo-intima extended with time as the myofibroblasts increased in number, as the collagen fibers thickened, and as the inflammatory cells grew more scarce. Its thickness ranged from 50 to 3,500 microm, the maximal values being observed in the middle of the shunt. The shunt was obstructed by a clot in 4 patients (18%). In 7 shunts (31.8%) the pseudo-intima was thicker than 1,000 microm and was referred to as hyperplastic pseudo-intima. It showed more dense inflammatory infiltrate and anarchic deposition of more scarce collagen fibers. Pseudo-intima hyperplasia was associated with previously diagnosed thrombosis, which had been treated by dilatation in 2 cases and by biliary deposits in 3 cases, while it remained unexplained in 2 cases. Accordingly, this study confirms the following: 1) that early TIPS obstruction results from thrombosis; 2) that 2 weeks after insertion, the stent is covered by a smooth pseudo-intima; 3) that thereafter, pseudo-intimal hyperplasia is the main cause of TIPS stenosis or occlusion; and 4) that biliary secretions and previous thrombosis could be important triggering mechanisms for this pseudo-intima overgrowth.

Adult↗
PubMed1997

Percutaneous recanalization of acutely thrombosed vessels by hydrodynamic thrombectomy (Hydrolyser).

A hydrodynamic thrombectomy catheter was prospectively evaluated for the treatment of recently thrombosed vessels. A total of 52 consecutive patients (42 males and 10 females; mean age 64 +/- 15 years) presenting with acute or subacute occlusion of dialysis shunts (n = 25), peripheral bypass (n = 14) or native arteries (n = 15) were treated with the Hydrolyser (Cordis Europa NV, Roden, The Netherlands). Mean occlusion time was 4 days (range 1-17 days) and mean thrombus length 19 +/- 11 cm. The Hydrolyser was effective and fast in removing thrombus, regardless of the thrombus length. No major complications were reported. The immediate procedure success rates were 82, 100, 87 and 79 % for Brescia Cimino, dialysis shunt, native arteries and bypass grafts, respectively. Adjunctive thrombolysis (applied for persistence of residual thrombus or thrombosed distal vessels too small for hydrolytic thrombectomy) was required in 4 % of thrombotic dialysis shunts, in 20 % of native arteries and in 50 % of bypass graft occlusions. On angiographic controls, distal embolizations were reported only in native arteries (13 %) and bypasses (14 %); all were successfully treated percutaneously, except for one case treated by Fogarty balloon. Cumulative primary patency rates were respectively at 6 months 56, 62, 78 and 65 % for each indication. We conclude from this preliminary clinical study that hydrodynamic thrombectomy with a Hydrolyser is a promising technique to treat acute occlusions. This device can reduce complications as well as the time required to remove large amounts of thrombus and the use of expensive thrombolytic drugs.

Angiography↗
PubMed1997

[Cystic adventitial disease: importance of computed tomography in the diagnostic and therapeutic management].

PURPOSE: Popliteal artery entrapment and adventitial cystic disease are the main causes of claudication in young patients. Adventitial cystic disease is a rare vascular pathology mostly affecting the popliteal artery but other localisations have been reported. Diagnosis and therapeutic management of adventitial cystic disease and particularly percutaneous aspiration are presented. MATERIALS AND METHODS: The authors report six cases (four men and two women; mean age: 55) of CAD of the popliteal artery (n = 4) and unusual cases in the femoral artery (n = 1) and in the femoral vein (n = 1) explored by sonography, computed tomography (CT), magnetic resonance imaging (MRI) and angiography. Five patients were initially treated by CT-guided aspiration and one with endoprosthesis. RESULTS: Sonography, CT or MRI are more useful to establish the diagnosis because these techniques can directly visualize the arterial wall. All these patients but one have been treated by percutaneous method with a good functional outcome but surgical intervention was necessary for two of them because of cysts recurrence. CONCLUSION: Our experience suggests that percutaneous CT-guided aspiration is the first treatment option for small cysts but close long-term follow-up is necessary to detect recurrence.

Adult↗
PubMed1996

[Adventitial cyst of the popliteal artery. Imaging and percutaneous treatment].

Adventitial cystic disease of the popliteal artery is a rare cause of calf claudication in young patients. A case explored by magnetic resonance imaging is reported: a water rich mass around the popliteal artery compressed the arterial lumen. Treatment consisted in CT-guided percutaneous aspiration. Good functional outcome except for severe efforts, despite persistance of cystic images was observed. Echography, computed tomography or magnetic resonance imaging are more useful to establish the diagnosis than arteriography because these techniques can directly visualize the arterial wall. Percutaneous treatment preserves the intima and can be performed in out-patients. When feasible, it could be preferred to conventional surgery.

Adult↗
PubMed1996

[Treatment with endoprosthesis of the pathology of the descending thoracic artery].

Surgery and medical treatment have been classically accepted as the therapy of choice in some diseases of the thoracic aorta. Recently, treatment with endoprosthesis has emerged as a useful technique in the pathology of the descending thoracic aorta. The type of endoprosthesis, indications and experimental and clinical results are discussed.

Aortic Dissection↗
PubMed1995

[Percutaneous treatment of popliteal aneurysms using a covered stent: preliminary clinical experience].

This report describes preliminary results with stented grafts (Cragg EndoPro) for treatment of popliteal aneurysms in 3 consecutive patients (3 men, average age 68 years, varying from 44 to 81 years old). One to 4 transluminally placed stented grafts (50 to 100 mm of length and 8 to 10 mm in diameter) were used to treat 3 popliteal aneurysms. The procedures were successful in all cases, under local anesthesia, without hameodynamic compromise or major complications. Angiography and color Doppler demonstrated patency and aneurysm exclusion, up to 9 months with these stented grafts in all cases except for one case occluded 15 days after stent insertion. Although technical success and short-term patency have been good with this technique, long-term patency is not yet known. The use of these stented grafts already appears justified in critically ill patients, but durability must be established in relation to traditional bypass surgery before it can be recommended on a wider scale.

Adult↗
PubMed1994

[Stenosis of the renal artery of the transplant: comparison between interventional and medical treatment].

In a retrospective analysis of 542 renal transplantations performed over a 10 years period, we diagnosed 25 cases of renal allograft artery stenosis that is a prevalence of 4.6%. The reason for angiography was persistent hypertension and/or renal insufficiency. An interventional procedure was performed in 16 patients (group 1): surgery in 5 and transluminal angioplasty (PTA) in 11. Nine other patients were medically treated (group 2). PTA or surgery was undertaken when a significant stenosis (> 70%) was found and when hypertension was severe (mean PAM = 123 +/- 11 mmHg). PTA was primarily performed when the anatomical situation of the stenosis was judged suitable. Medical treatment was chosen because the stenosis was assesses as not being severe enough or because was considered unsuitable for correction. Interventional treatment was successful in 77%. Long term results are shown in the table: in both 2 groups blood pressure decreased significantly at mean follow-up; the number of antihypertensive drugs decreased non significantly but are still necessary in the group 1. Mean serum creatinine is not significantly modified after treatment, there is no degradation of renal function in group 2 and no amelioration in group 1.

Adult↗