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Biomedical subjects

C Chagnaud

Publications and source records attributed to C Chagnaud.

At least 37 records · Page 2Linked to original sources
PubMed1997

Bone mineral density in patients given oral vitamin K antagonists.

BACKGROUND: Divergent results have been obtained in studies of bone mineral density in patients under oral vitamin K antagonists. OBJECTIVE: To gather prospective data on bone mineral density and bone metabolism in 70 aortic valve replacement patients. STUDY DESIGN: 49 patients who had been under oral vitamin K antagonists for at least one year after implantation of a mechanical aortic valve were compared with 21 recipients of a tissue aortic valve that did not require anticoagulant therapy. The following investigations were done in all patients: (1) dual-energy X-ray absorptiometry measurement of bone mineral density at the lumbar spine and femoral neck; (2) roentgenograms of the spine and pelvis; (3) serum assays of calcium, phosphate, creatinine, alkaline phosphatase, osteocalcin, 25-OH-vitamin D3, and parathyroid hormone. RESULTS: The two groups were comparable regarding age and sex ratio. No differences were found in lumbar or femoral neck bone mineral density even after adjustment for age and sex. A trend toward an increase in bone mineral density at both sites with increasing duration of vitamin K antagonist therapy was demonstrated. The only bone turnover marker difference between the two groups was a significantly lower serum osteocalcin level in the group under vitamin K antagonist therapy (P < 0.0001). CONCLUSIONS: Long-term vitamin K antagonist therapy does not affect bone mineral density at the lumbar spine or femoral neck and also fails to modify bone turnover markers, with the exception of osteocalcin.

Administration, Oral↗
PubMed1996

Radiation dose to the lenses in CT of the paranasal sinuses.

The radiation dose to the lens during CT of the paranasal sinuses was measured in 20 patients. In 10 patients, a "standard" technique with axial and coronal sections was used. In the remaining 10 patients, overlapping axial sections for bidimensional reconstruction were obtained. Radiation dose was measured using thermoluminescent dosimeters. The mean dose was 22 mGy in patients who underwent "standard" CT and 42 mGy in those who underwent CT with overlapping sections. Dose was dependent on the total number of slices and of transorbital axial sections. Coronal sections did not statistically increase the radiation dose to the lenses. Although these doses were significantly below the critical dose for cataracts, CT with overlapping sections gives a considerably higher radiation dose. We recommend the bidimensional reconstruction technique only for selected cases (e.g. preoperative assessment of the roof of the ethmoid sinuses or in patients who can or should not maintain the hyperextended position required for coronal views.

Ethmoid Sinusitis↗
PubMed1996

Iobitridol 250 vs iohexol 240 in phlebography of th lower limbs. A double-blind clinical trial.

Iobitridol 250 (Xenetix 250) was compared with iohexol 240 (Omnipaque 240) in phlebography of the lower limbs by means of a multicenter, randomized double-blind trial in 70 patients. No significant difference was demonstrated between the 2 groups in terms of diagnostic efficacy, image quality or clinical safety. Only minor reactions were recorded in the 2 groups, essentially consisting of mild or moderate heat sensations. The only insufficiently informative examinations were not due to the contrast agent. Iobitridol 250 therefore appears to be a well-tolerated contrast medium, suitable for use in phlebography of the lower limbs.

Contrast Media↗
PubMed1995

Role of magnetic resonance imaging in predicting late facial motor function after removal of vestibular schwannomas by the translabyrinthine approach.

Facial motor function was assessed in 61 patients 18 months after surgical resection, by the translabyrinthine approach, of vestibular schwannoma involving both the cerebellopontine angle (CPA) and the auditory canal. Pre-operative magnetic resonance imaging (MRI) was performed to measure the maximum extracanalicular diameter of the tumour between the porus and the farthest extension in the CPA on transverse slices and to calculate extracanalicular tumour volume. Post-operative facial motor function was graded according to the House and Brackmann system. There was a statistically significant relationship between late facial motor function and extracanalicular diameter. The best cut-off point for good and poor results was 20mm. There was no relationship between the tumour volume and the late post-operative facial motor function grade. In this study the best pre-operative radiological predictor of the late facial motor function in patients operated on by the translabyrinthine approach was the maximum diameter measured by MRI.

Adult↗
PubMed1995

Type A dissection of the thoracic aorta: use of MR imaging for long-term follow-up.

PURPOSE: To evaluate routine magnetic resonance (MR) imaging for long-term follow-up in patients who undergo surgery for type A aortic dissection. MATERIALS AND METHODS: Ninety-two MR examinations were performed in 36 patients. Standard spin-echo images were obtained with electrocardiographic gating (n = 92) and rapid images with a fast low-angle shot sequence and intravenous administration of gadopentetate dimeglumine (n = 25). All segments of the native thoracic aorta were evaluated. Anastomoses of the prosthesis and periprosthetic hematoma were carefully analyzed. RESULTS: Of 22 complications that occurred in 18 patients, 18 were diagnosed at MR imaging (nine false aneurysms and nine aneurysms distal to the graft). Nine patients underwent reoperation. The findings at MR imaging correlated with those at surgery. CONCLUSION: Routine follow-up with MR imaging should improve long-term survival in patients who survive emergency surgical repair of type A aortic dissection.

Aortic Dissection↗
PubMed1994

Protrusion of the optic nerve into the ethmoid and sphenoid sinus: prospective study of 150 CT studies.

Damage to the optic nerve is a serious complication of intranasal sinus surgery. Protrusion of the optic canal into the sphenoid sinus is a major risk factor. In this prospective study of 150 CT studies, we found this anatomical variation in 8% of cases. It was consistently associated with pneumatisation of the ipsilateral anterior or clinoid process. Protrusion of the optic nerve into the posterior ethmoid cells was never observed. CT is a useful part of the preoperative investigation of patients undergoing intranasal sinus surgery. Axial and coronal images obtained or by direct acquisition by reconstructions are necessary to show the position of the optic nerve.

Adult↗
PubMed1994

[Intra-arterial thrombolysis using rt-PA for the treatment of occluded infra-inguinal bypasses].

From July 1990 to July 1993, we performed 41 percutaneous intra-arterial thrombolysis procedures for the treatment of obstructed infra-inguinal bypass grafts in 32 patients. There were 27 men and five women with a mean age of 63 +/- 17 years (range 21 to 83 years). The symptoms of occlusion were intermittent claudication in three cases, rest pain in 12 cases, severe ischemia without sensitive-motor loss in 26 cases. Bypasses were achieved using a prosthesis in 18 cases (43.9%), a saphenous vein in 10 cases (24.4%), an arterial allograft in nine cases (21.9%), and a composite prosthesis-vein graft in four cases (9.8%) (table I). The distal anastomosis of the bypass graft was located on the popliteal artery in 26 cases (63.4%) and a crural artery in 15 cases (36.6%). The mean duration of the occlusion was 4.9 +/- 3.4 days (range 1 to 15 days). The percutaneous approach was through the contralateral common femoral artery in 26 cases (63.4%), through the ipsilateral common femoral artery in seven cases (17.1%), through the left humeral artery in eight cases (19.5%). In all cases the thrombolytic agent was the recombinant tissue-type plasminogen activator (rt-PA). Each procedure began with the injection of a five milligram bolus of rt-PA into or onto the thrombus followed by infusion of rt-PA into the thrombus at a dose of 0.05 mg/kg/h. Intravenous heparin was simultaneously administered. Serum fibrinogen, prothrombin time, and partial thromboplastin time (PTT) were measured every three hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Dehiscence of the lamina papyracea of the ethmoid bone: CT findings.

PURPOSE: To describe the CT findings characterizing dehiscence of the lamina papyracea. METHODS: Axial and coronal CT scanning of the paranasal sinuses was performed on 783 patients. RESULTS: Dehiscence of the lamina papyracea was noted incidentally in six patients. In all cases dehiscence was characterized by protrusion of orbital fat through a gap in the anterior ethmoid. The posterior limit of the dehiscence was always the basal lamella. The anterior limit varied. CONCLUSION: CT scans are often taken to detect polyps or assess chronic sinusitis. Awareness of dehiscence of the lamina papyracea is important to avoid misdiagnosis as infectious or tumoral process and possible injury of the orbit during endoscopic surgery.

Congenital Abnormalities↗
PubMed1993

Early-stage avascular necrosis of the femoral head: MR imaging for prognosis in 31 cases with at least 2 years of follow-up.

Thirty-one cases of stage 1 or 2 osteonecrosis (ON) of the hip in 27 patients were studied with T1-weighted coronal magnetic resonance (MR) imaging. Three quantitative parameters were measured on the contiguous MR sections, corresponding to the 2-cm-wide median portion of the femoral head: the angle filled by ON (alpha), the percentage of weight-bearing femoral cortex involved with ON (WB), and the percentage of femoral head surface involved with ON. The clinical and radiologic courses were assessed after at least 2 years of follow-up (mean, 46 months). Core decompression was performed in 12 cases of ON. Values were strikingly lower in the group with good clinical or radiologic outcome versus poor outcome, with very little overlapping. WB was the more reliable parameter. Outcome of hips treated with versus without core decompression appeared closely related with these MR parameters and not with the treatment procedure. Thus, a quantitative approach to determination of extent and location of the lesion on the initial MR image appears accurate for use in the prediction of long-term outcome of ON. Effectiveness of core decompression should be reevaluated on this basis.

Adult↗
PubMed1992

[Ioversol 300 and iopamidol 300 in "whole body" computed tomography. A double-blind clinical trial].

The authors compared ioversol 300 to iopamidol 300 by double blind study in patients undergoing enhanced computed body tomography. There was no significant difference in clinical tolerance and efficacy between the two products. Only minor reactions were recorded in both groups. Contrast media were not considered to be responsible for the poor diagnostic quality of a few explorations. Ioversol 300 appears as a well tolerated and effective contrast medium for computed body tomography.

Adult↗
PubMed1992

[Aspects and role of spinal MRI in the assessment of solitary plasmacytoma and multiple myeloma. Apropos of 11 cases].

Spinal MRI was performed in 9 multiple myeloma and 2 solitary plasmacytoma, using sagittal, T 1-weighted (TR: 350-550 ms/TE: 15-26 ms) and T 2-weighted (TR: 2,000-2,500 ms/TE: 60-120 ms) sequences, with additional gadolinium injection in 3 cases. MRI features were the following: 1) round, patchy lesions with low T 1 signal highlighted by gadolinium and bright T 2 signal were present in 10 of the 11 patients: all osteolytic lesions seen on plain X-rays corresponded to such lesions and biopsy performed in 4 cases showed massive marrow replacement by plasma cells. 2) overall marrow signal was dramatically decreased in 3 patients (2 of whom had a high tumoral mass). 3) extra-dural compression was present in 4 cases. 4) 25 vertebral compression fractures (10 of whom with a "benign" appearance) and focal fat deposition were seen. 5) postradiation treatment examination seemed predictive of the outcome in the 2 solitary plasmacytomas. MRI proved to be more sensitive than plain X-rays or bone scintigraphy. Number and size of focal tumor-like lesions did not correlate with the low marrow signal appearance. Both correlated poorly with overall tumoral mass but diffuse abnormalities were associated with rapidly fatal outcome in three cases. These features might reflect qualitative rather than quantitative patterns of the disease (nodular or diffuse macroscopic marrow replacement). These findings are in agreement with those of the few previous studies. MRI is valuable for spinal cord damage assessment. It appears less accurate in benign versus malignant vertebral compression fracture determination than it does in bone metastasis. Its prognostic value is still questionable.

Aged↗
PubMed1992

[Extrapleural hematoma].

The authors report a case of a voluminous extra-pleural hematoma in relation to a fracture of the body of the eleventh thoracic vertebra on a 74 year-old man after craniothoracic injury. Thoracic CT Scan showed a homogeneous posterior parietal mass of tissue density (40 HU) outlined by a fatty lining associated with a fracture of the eleventh thoracic vertebra. This allowed a modification in the diagnosis of a hemothorax established previously on conventional radiography. The authors insist on the gravity of this affection when the volume of the hematoma is important. But this is very rare (6 cases out of which 5 were autopsic findings). If present it requise an urgent surgical treatment without forgetting the fiability of CT Scan which relies on putting into evidence the pleural lining sign.

Aged↗
PubMed1991

The normal uterus on magnetic resonance imaging and variations associated with the hormonal state.

Magnetic Resonance Imaging of the pelvis has lead to a new radioanatomical description of the uterus. Variations in the anatomical zones of the uterus were noted with different sequences used in MRI. There was also structural and signal variation depending on hormonal impregnation. Twenty seven MRIs of pelvices were carried out on 16 female volunteers. Eight of them were on oestroprogesterone as the method of contraception (Group I) and had a single MRI. Six were not taking contraceptives (Group II) and had different MRI's during the same cycle. Two women already had already gone through the menopause (Group III). Results showed differences in the size of the uterus (uterine height, length of the uterine body and cervix, diameter of the cervix) between groups I and II but no cyclic changes were observed within group II. The myometrium was found to be thicker in group I and in the luteal phase of group II females in comparison to the follicular phase in the same group. The endometrial cavity was seen in 40% of cases on T1 weighted sequences; on T2 weighted sequences it was seen in all the cases. It was thicker during the second phase in group II than in group I and III. The myometrial signal compared to that of the bladder content (urine) showed a significant increase between early and late echoes on T2 weighted sequences in group I and during the second phase of the menstrual cycle in group II. No variations, or at times a decrease in signal, were observed during the first phase of the cycle in group II.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗