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Biomedical subjects

J F Heautot

Publications and source records attributed to J F Heautot.

14 recordsLinked to original sources
PubMed2004

[Renal arteriovenous fistula associated with fibromuscular dysplasia of the renal arteries].

Three to 5% of hypertensive diseases have a renovascular origin. Atherosclerosis and fibromuscular dysplasia are the two major causes of renovascular hypertension. Association of renal arteriovenous fistula and fibromuscular dysplasia is uncommon. The authors propose to illustrate the usefulness of Doppler ultrasonography and digital subtraction angiography in the diagnostic and therapeutic management of a renal arteriovenous fistula associated with fibromuscular dysplasia discovered after severe preeclampsia in a 30 year-old woman.

Adult↗
PubMed2001

[Coronary steal syndrome by systemic pulmonary hypervascularization fed by a mammary-left anterior descending artery bypass. Treatment by embolization].

We report a case of coronary-steal syndrome which occurred after coronary bypass surgery. It was related to systemic hypervascularization of the lung caused by a bronchopathy. The steal syndrome was fed by an ectopic bronchial artery arising from the internal mammary--left anterior descending artery bypass graft. The myocardial ischemia disappeared after hyperselective embolization of the ectopic bronchial artery. The authors outline the rarity of this syndrome and its pathophysiology. They insist on the necessity to perform broncho-systemic arteriography for candidates to coronary surgery, in patients with thoracic diseases which can induce systemic hypervascularization of the lung.

Bronchial Arteries↗
PubMed2000

The RETAIN project: DICOM teleradiology over an ATM-based network. Radiological Examinations Transfer on an ATM Integrated Network.

The RETAIN project (Radiological Examinations Transfer on an ATM Integrated Network) has aimed at testing videoconferencing and DICOM image transfers to get advice about difficult radiological cases over an asynchronous transfer mode (ATM)-based network, which affords a more comfortable interface than narrow-band networks and allows exchange of complete image series using the DICOM format of studies. For this purpose, an experimental ATM network was applied between six university hospitals in four different countries. An assessment of the functionalities of the system was performed by means of log-file analysis, video recording of the sessions and forms filled out by the participants at the end of each session. Questionnaires were answered by the users at the end of the project to bring out perspectives of utilisation and added value. We discussed 43 cases during 20 sessions. For technical or organisational problems, only 20 of the 36 planned sessions took place. The throughput over ATM (10.5 Mbit/s, 20 times faster than six ISDN B-channels) was adequate. Despite the experimental configuration of the network, the system was considered as satisfactory by all the physicians. In 72 % of the sessions, the expected result (answer to the question) was gained. By common consent, videoconferencing was unanimously regarded as a prominent tool in improving the interaction quality. Asynchronous transfer mode is an efficient method for fast transferring of radiologic examinations in DICOM format and for discussing them through high-quality videoconferencing.

Computer Communication Networks↗
PubMed1998

Analysis of cerebrovascular diseases by a new 3-dimensional computerised X-ray angiography system.

We set out to validate the concept of three-dimensional (3D) angiography. We evaluated the sensitivity and the quality of morphological analysis mode possible by an experimental system for imaging cerebrovascular disease versus standard digital subtraction angiography (DSA). The system, the 3D Morphometer, is a computerised X-ray angiography unit capable of acquiring a set of two-dimensional (2D) projections during a rotation and then reconstructing a 3D volume from them. We studied 78 patients with suspected cerebrovascular disease. 3D and 2D images (standard 2D DSA performed during the same procedure), were reviewed blindly to assess detection and display of morphological characteristics of cerebrovascular diseases. We found 53 aneurysms, 22 arteriovenous malformations and two venous angiomas. On 3D angiography we detected two aneurysms we missed on 2D angiography. In 47 aneurysms on which further data were obtained during surgery or embolisation, the 3D angiography allowed more accurate analysis of the neck and surrounding vessels in cases in which the 2D angiographic findings were doubtful. Assessment of arteriovenous malformations was equivalent with both techniques. Under the conditions of our study, the technical constraints being the same for both methods, 3D angiography was superior to 2D angiography. Implementation on C-arm vascular systems is being evaluated.

Algorithms↗
PubMed1997

Prospective randomized trial of chemoembolization versus intra-arterial injection of 131I-labeled-iodized oil in the treatment of hepatocellular carcinoma.

Intra-arterial injection of radioactive Lipiodol has shown promising results in patients with hepatocellular carcinoma (HCC) and portal obstruction. The aim of this prospective, randomized trial was to compare the efficacy and tolerance of 131I-labeled Lipiodol and chemoembolization for the treatment of patients with HCC. From September 1990 to September 1993, 142 patients (135 men, 7 women; age: 65 +/- 6.6 years) were randomly assigned to treatment groups and given either intra-arterial injections of 131I-labeled Lipiodol (60 mCi; 2.2 GBq) (n = 73) or chemoembolization (70 mg cisplatin) (n = 69). Subsequent injections were given at 2, 5, 8, 12, and 18 months. Tumor response was assessed on the basis of tumor size and serum alpha-fetoprotein levels. Patient tolerance was assessed clinically and angiographically. Survival rate was the main end-point. A total of 129 patients (65 in the 131I-labeled Lipiodol group and 64 in the chemoembolization group) were available for analysis; 13 were excluded, mainly because of portal vein thrombosis. The two groups were comparable. Actuarial survival curves were not significantly different between the two groups. Overall survival rates at 6 months, 1, 2, 3, and 4 years were 69%, 38%, 22%, 14%, and 10%, and 66%, 42%, 22%, 3%, and 0% in the 131I-labeled Lipiodol and chemoembolization groups, respectively. Reduction in tumor size was similar for the two groups, with complete response in 1 and 0 patients and partial response in 15 and 16 patients in the 131I-labeled Lipiodol and chemoembolization groups, respectively. Tolerance was significantly better in the 131I-labeled Lipiodol group both clinically (3 severe side effects vs. 29 in the chemoembolization group; P < .001) and angiographically (1 arterial thrombosis vs. 10 in the chemoembolization group; P < .01). In terms of patient survival and tumor response, radioactive 131I-labeled Lipiodol and chemoembolization were equally effective in the treatment of HCC, but tolerance to 131I-labeled Lipiodol was significantly better.

Aged↗
PubMed1996

[Test of a teleradiology network based on ATM (asynchronous transfer mode)].

The retain project (Radiological Examination Transfer on ATM Integrated Network) consisted in teleradiology trials focused on pediatric imaging between two university hospitals. Rennes (France) and Barcelona (Spain) using an integrated broadband communication network based on ATM (asynchronous transfer mode), as part of a European research program. The network used was a full 10 Mbits/s ATM network directly connected to local PACSs (medical imaging hospital networks). One important reason to explicitly consider ATM for medical imaging is that multimedia applications on such networks allow integration of digital data and person-to-person communication. The utility of broadband communication for teleradiology has been confirmed. High quality video and sound are important for both human communication and medical video transfer. The project led to guidelines regarding technical options still open to improvement.

Computer Communication Networks↗
PubMed1994

MR lymphography: study of a high-efficiency lymphotrophic agent.

PURPOSE: To investigate the utility of a monocrystalline iron oxide nanoparticle (MION) as a contrast agent in magnetic resonance (MR) imaging of lymph nodes. MATERIALS AND METHODS: Pharmacokinetic data were obtained in rats after intravenous, subcutaneous, and intraarterial injection of indium-111-MION-46. MR imaging was performed to determine optimal dosages and pulse sequences in rats. Models of lymph node metastasis in rabbits and lymph node hyperplasia in rats were used to demonstrate the efficacy of MION in differentiation of malignant and benign adenopathies. RESULTS: Biokinetic data indicate that nodal accumulation occurs primarily after extravasation of agent into the interstitial space (slow component) and subsequent trapping by lymph node macrophages (fast component). Relatively low concentrations (15-25 mumol Fe per kilogram for peripheral nodes after intraarterial injection) decrease signal intensity of nodes at MR imaging. CONCLUSIONS: Lymph node accumulation of MION-46 is high. Modification of injection techniques that alter capillary permeability allows use of systemically administered agent at doses as low as 15-25 mumol Fe per kilogram.

Animals↗
PubMed1994

Hemochromatosis: diagnosis and quantification of liver iron with gradient-echo MR imaging.

PURPOSE: To assess the role of magnetic resonance (MR) imaging in detection and quantification of liver iron overload. MATERIALS AND METHODS: MR imaging at 0.5 T was prospectively performed on 77 patients (67 with liver iron overload and 10 without) who underwent a liver biopsy with biochemical determination of the liver iron concentration (LIC) (normal, < 36 mumol per gram of liver tissue [dry weight]). Ratios of signal intensities and liver T2 relaxation time were calculated from images obtained with spin-echo and breath-hold gradient-echo (GRE) sequences. RESULTS: Liver-to-tissue signal intensity ratios were better correlated with LIC than T2 relaxation time. Long-echo-time GRE sequences were the most sensitive for detection of slight overload. Thus, high sensitivity (94%) and specificity (90%) were obtained with a liver-to-fat ratio threshold of 1. The quantification of iron with MR imaging was accurate when the LIC was 80-300 mumol/g. For heavy overload, above 300 mumol/g, quantification was impossible owing to complete signal loss. Pancreatic and splenic signal intensity were unchanged in most cases. CONCLUSION: This method, which can be improved by using more sensitive sequences with a high-field-strength system, should be competitive with biopsy for the diagnosis of substantial liver iron overload.

Female↗
PubMed1993

[Station of interpretation].

Revisualization or image processing stations are constantly improving, but they have not yet been designed to replace the x-ray display unit for the interpretation of films. An improvement of the integration of these stations within the hospital computer system and functional enrichment must be achieved in order to prepare for the "digital" era. Although this prospect is not for the immediate future, it is important to develop tomorrow's tools with a minimum of intelligence to facilitate their acceptance.

Humans↗
PubMed1992

Magnetic resonance imaging and assessment of liver iron content in genetic hemochromatosis.

Computed tomography (CT) scanning is not highly sensitive in the assessment of liver iron content and magnetic resonance imaging (MRI) appears to be more efficient. The aim of this study was to determine the effectiveness of MRI in the evaluation of liver iron content using a standard spin-echo technique. The study included 23 patients with genetic hemochromatosis and 24 non-iron-overloaded patients as controls. A comparison was made of: (a) MRI signal intensity of liver, spleen, paravertebral muscles and subcutaneous adipose tissue using two different spin-echo sequences (SE 500/28; SE 2000/28,56); (b) liver attenuation determined by a single energy CT scan; and (c) a biochemical determination of hepatic iron. There was a significant decrease in liver signal intensity in the genetic hemochromatosis group (256 +/- 201, mean +/- S.D.) compared with the control group (801 +/- 413, p less than 0.001), but there was no correlation with liver iron concentration. However, such a correlation was found and was even more highly significant than in CT when the ratio between the liver and another organ was taken into account. For a lower limit of liver/spleen ratio calculated at 0.46 (mean 2 S.D. in the control group), the specificity (0.96) of MRI was satisfactory, but the sensitivity (0.78) remained insufficient (MRI being unable to detect an iron overload of up to 125 mumol/g). Hopefully, these results might be improved in the near future by using more sensitive sequences such as gradient echo sequences.

Adipose Tissue↗
PubMed1987

Splenic pseudoaneurysm rupture into the colon: colonoscopy before and after successful arterial embolization.

We report a case of splenic pseudoaneurysm rupture into the colon in chronic pancreatitis. At the time of bleeding, pancreatitis was undiagnosed and the colonic lesion was misinterpreted at colonoscopy. The lesion was also misinterpreted at laparotomy, because it simulated intra-abdominal carcinomatosis. The diagnosis was made by CT examination which showed an eccentric enhancing region within a hypodense mass in the region of the splenic hilum. Definitive control of bleeding was achieved by splenic arterial embolization. Splenic infarction and an intrasplenic abscess complicated the embolization, but they did not require surgical intervention. Healing of the colonic wall and of the colonic mucosa was observed at colonoscopy 3 weeks after the embolization.

Aneurysm↗
PubMedDate not supplied

Superparamagnetic iron oxide: clinical time-response study.

Superparamagnetic iron oxide (AMI 25) is a promising new contrast agent for imaging the reticuloendothelial-system. Iron oxide crystals possess a large magnetic susceptibility and enhance proton relaxation rates, especially transverse relaxation (T2). In order to guide the clinical utilization of this contrast media we analyzed 4 patients with malignant lesions of the liver before and after slow intravenous administration (20 mumol Fe/kg) of AMI 25. We performed two magnetic resonance (MR) sequences at different times using a 0.35 T magnet. MR signal-to-noise ratio (SNR) of the reticuloendothelial system (particularly the liver SNR) decrease promptly. The maximum decrease in SNR (67-72% for the liver, 46-65% for the spleen, 23-41% for the bone marrow) is observed 3 h after injection (P less than 0.01). However, except the peak of contrast enhancement in T1-weighted sequences of splenic tissue, the curve describes a plateau within 30 min and 6 h, allowing a delay between injection and imaging. T2-weighted sequences give a greater contrast-to-noise ratio (CNR) by adding the spontaneous tumor contrast to the effect yielded by AMI 25. These results suggest that images must be acquired between 1 and 6 h after intravenous administration of superparamagnetic iron oxide.

Aged↗
PubMedDate not supplied

Influence of the teleradiology technology (N-ISDN and ATM) on the inter-hospital management of neurosurgical patients.

We set out to assess the influence of a teleradiology network on the relations between a general hospital and a 100 km distant university hospital in the context of neurosurgical emergencies, and compared a commercially available technology, N-ISDN (Narrowband Integrated Service/Digital Network), to an emerging technology, ATM (Asynchronous Transfer Mode). The evaluation was conducted using records of advice request calls and patient transfers. Three phases were considered: without teleradiology, with transfer of digitized images over N-ISDN at 64 kbps, and with an experimental ATM network at 10.5 Mbps with DICOM image transfers and videoconferencing. Additionally, staff meetings over ATM videoconferencing were set up. To assess the ATM service, we used log files and questionnaires, 108 advice requests were studied over a 18 month period. The average transmission time for one examination was 38 s with full DICOM image resolution over ATM, versus 150 s with 10:1 JPEG (Joint Photographic Expert Group) compression over N-ISDN. Up to 50% unnecessary patient transfers were avoided. Advice requests increased fourfold, and non-urgent advice requests increased from 0 to 21%. Despite the experimental configuration of the ATM network, the service gave satisfaction to all the physicians. Videoconferencing was unanimously regarded as a prominent tool to improve the quality of interaction. It was particularly useful for non-urgent cases and distant staff meetings. Teleradiology can improve the relations between hospitals through an increase of urgent and non-urgent advice requests. Asynchronous transfer mode is an efficient way for fast transfer of radiological examinations in DICOM format and for discussing them through high-quality videoconferencing.

Brain Neoplasms↗