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Biomedical subjects

P Vinée

Publications and source records attributed to P Vinée.

15 recordsLinked to original sources
PubMed1995

[Percutaneous needle biopsy in skeletal metastases. Indications, technique, value and results].

Although modern imaging techniques have improved diagnostic specificity in osteolytic and osteoplastic lesions, histological examination is often still mandatory when primary bone tumors or skeletal metastases are concerned. We have developed a percutaneous puncture set, including sufficiently steady, but still fine biopsy needles (1.4-2 mm) and a slow rotating drill accessory. With this set, histological material can be obtained from almost anywhere in the skeleton with local anesthesia low complication risk, and low patient stress and discomfort. Together with the high accuracy of CT- or fluoroscopy-guided puncture (near 95%), this allows biopsies to be taken on an outpatient basis, with broad indications. Biopsy can be used early when making a diagnosis. Tedious searching for the primary tumor can thus be avoided with subsequent economic benefits.

Adult↗
PubMed1994

Detection of glomus tumor of the finger by dedicated MRI at 0.1 T.

Three glomus tumors of the fingers were detected using a dedicated hand and wrist low field (0.1 T) MR imager equipped with solenoidal coils allowing a FOV of 2 cm. Three-dimensional T1-, T*2-, or T2-weighted images were used (8 contiguous slices of 2 mm thickness). Glomus tumors had low or intermediate signal intensity (2 cases) or no signal (1 case) on T1-weighted images. On T*2- or T2-weighted images they had high signal intensity. MRI findings correlate well with surgery and biopsy.

Adult↗
PubMed1993

In vitro proton NMR study of collagen in human aortic wall.

The authors relate the findings in the 1H solid state line shape (at 60 MHz) of human aortic walls (n = 12) in native state and after histologically controlled selective lysis of collagen and elastin. An analysis of the line shape shows a composite free induction decay (FID) consisting of a low amplitude (3-7%) fast decaying component (T2 approximately 20 microseconds) and a slow decaying one (T2 > 1 ms). The fast component is identified as the protons of the collagen macromolecules. The second moment computed from the experimental fast component of the FID is in agreement with published studies examining the motional characteristics of collagen by multinuclear NMR employing spin labeling. A theoretical second moment is computed for the collagen macromolecular backbone from the atomic positions in the superhelix. Comparison with the observed experimental values allows determination of the step angle (29 degrees) of the fast rotational motion of the collagen strands along their long axis.

Aged↗
PubMed1993

Characterization of human aortic collagen's elasticity by nuclear magnetic resonance.

The elasticity of the human aortic wall in longitudinal uniaxial elongation at high strain, known to be determined mostly from tissular collagen's behaviour, is studied and compared to the second moment of the 1H nuclear magnetic resonance (NMR) solid state line-shape, a proton nuclear magnetic resonance (at 60 MHz) characteristic for the molecular motion and the rigidity of the collagen macromolecular backbone. The 1H NMR signal of collagen is identified after selective histologically controlled chemical lysis. The computed second moment of the line-shape shows statistically significant correlation with the slope of the strain-stress curve of the aorta at high strain, thus proving the relationship between a macroscopic tissular elasticity parameter and a macromolecular rigidity characteristic of collagen, a major tissular component. In vivo extension of this technique (e.g., MRI) would allow us to gain information on the biomechanical state of the aorta, a naturally highly stressed and strained tissue.

Aged↗
PubMed1993

[Metal abrasion as an imaging artefact in nuclear spin tomography].

Eighteen patients with vertebral body fractures that had been stabilized by an internal spinal skeletal fixation system were prospectively examined by magnetic resonance (MR) imaging between February 1989 and November 1990 at the Department od Diagnostic Radiology of the University Hospital Freiburg 3-7 days after removal of the metallic implants. In most cases imaging artifacts in the paraspinal extensor muscles were evident on MR studies. These were found especially in the region of the previous site of the metal clip jaw bearing. In a few cases artifacts were also present within the vertebral body and/or vertebral arch, but only if the vertebral body had been surgically reconstructed by transpedicular spongiosa implantation. None or only minor artifacts by abrasion of metal were detected if the (modified Schanz's) screws appeared to be tight at surgical removal of the implants. Therefore, marked metal artifacts on MR imaging retrospectively indicate a chronic straining of the implants, which has been shown to be a risk factor for implant loosening. Additional in vitro studies with powdered metallic alloy showed that as little as 1 mg of metal could be detected as artifacts in routine spin-echo sequences. When the metallic pieces were large enough to be seen on conventional radiographs or computed tomograms, they caused severe, distorting artifacts on MR imaging. It is concluded that MR imaging is the method of choice for detection of small amounts of metal.

Adult↗
PubMed1993

["Rare" urography by MRI: an alternative to IVU?].

The authors describe the technique of RARE sequences (Hennig, 1986) and their hydrographic application to urinary imaging, RARE urography. Heavily T2-weighted non-tomographic images of the urinary tract are obtained in less than 30 seconds, without contrast medium or ionizing radiation. The whole urinary tract is visualised on one image with a spatial resolution superior to that of sonography. The semiology of RARE urography is similar to that of the intravenous pyelogram. Silent kidneys are also visualised.

Adult↗
PubMed1992

Proton magnetic resonance relaxation times and biomechanical properties of human vascular wall. In vitro study at 4 MHz.

OBJECTIVES AND RATIONALE: Previous studies have suggested a relationship between tissue magnetic resonance (MR) relaxation times and its biomechanical behavior. To further investigate this relationship, the authors studied 41 human vascular wall samples from different anatomic localizations, including systemic and pulmonary arterial, as well as venous tissues. METHODS: The authors measured water content, proton MR T1 and T2 relaxation times, and two viscoelastic parameters of the samples at 4 MHz. RESULTS: T2, water content, and both viscoelastic variables significantly differed among the five anatomic localizations (P less than .05). Both T1 and T2 were significantly (P less than .05) and linearly related to viscoelastic parameters. Multiple linear regression showed that both viscoelastic parameters of a sample can be predicted from the measured values of T1 and T2. CONCLUSIONS: These results provide a basis for characterizing the mechanical stress of a tissue by knowing its MR relaxation times.

Adult↗
PubMed1992

[Uretero-arterial fistula. A rare cause of massive hematuria].

Ureteroarterial fistulae is a rare condition, with less than 25 reported cases. We describe such a fistula in a young female patient, after radiation therapy for cancer of the cervix and rectovaginal and vesicovaginal fistulae requiring sigmoidostomy and an ureteroureterostomy after long-lasting ureteral intubation. Angiography demonstrated the fistula and the reflux of contrast medium up to the pyelocalyceal cavities, and allowed establishing the origin of the massive hematuria, which caused the patient's death.

Adult↗
PubMed1991

[MR tomography of aneurysmal bone cyst].

The preoperative findings of magnetic resonance imaging (MRI) in six histology-proven aneurysmal bone cysts (ABC) are examined and compared with previous publications concerning MRI of ABC. The signal intensities differ considerably, and not all of our cases conform with the literature data. They can be summarised in three different subheadings: one form that is very inhomogeneous in T1- and T2-weighting, with fluid-fluid levels in the cystic spaces; one intermediate form without fluid-fluid levels, which is inhomogeneous only in T2-weighted images; and finally, an unusual form of ABC that has homogeneous low signal both in T1- and T2-weighting, and which has not been described in literature so far.

Adolescent↗
PubMed1991

[A 3 years' routine experience with a radiological information system].

We discuss the reasons for the system's installation and choice. The abilities and the structure of the RIS are summarized with special attention given to failures and defaults. Our system has been in use for more than 3 years and we describe our overall experience with its use. In addition, the results of a gallop poll concerning all the personnel category are given.

Evaluation Studies as Topic↗
PubMedDate not supplied

MR imaging of the pericardial cyst.

Findings obtained with magnetic resonance (MR) imaging in four patients with pericardial cyst are reported. MR imaging allowed not only localization and diagnosis in all four cases but characterization of cystic content. MR imaging, including RARE (rapid acquisition with relaxation enhancement) MR hydrography, which shows only liquids with T2s greater than 500 msec, proved to be useful in characterizing the fluid content of a mediastinal lesion and monitoring follow-up. In one case, MR imaging allowed differentiation of a pericardial cyst from a suspected necrotic lymph node in a patient with colic carcinoma, with subsequent correction of staging and therapy. The authors conclude that MR imaging is the method of choice for diagnosis (especially in unusual locations) and monitoring of pericardial cysts and for differential diagnosis of malignant mediastinal cystic tumors that show a solid part.

Diagnosis, Differential↗
PubMedDate not supplied

MR detection of quantitative and structural changes in human aortic aneurysms.

Collagen is a major component of the extracellular matrix and a determinant of the elastic behavior of the human aorta. To investigate the changes found in aneurysmal degeneration, the authors studied the solid-state hydrogen-1 nuclear magnetic resonance line shape of collagen in aneurysms and normal human aortas. A three-component decomposition of the free induction decay was performed, with collagen characterized by a T2 of about 18 microseconds. The second moment of the collagen line shape was found to be increased in aneurysms (5.3 vs 4.8 G2), while, correspondingly, the T2 of collagen was lower in aneurysms (16.3 vs 17.7 microseconds). This corresponds to a modification of collagen structure and molecular motion. Collagen concentration was lower in nondiseased aortic walls (9.4% vs 7.3%). These results are discussed in reference to the contradictory conclusions in the current literature. The increase in collagen and the modification of its structure and molecular motion are explained by the need to resist an increasing tangential tension due to increased aortic diameter and diminished wall thickness in aneurysms and by intercalation or site binding in the helices or electric dipolar interactions in the less mobile side groups.

Aorta, Abdominal↗
PubMedDate not supplied

Value of 3D CT imaging in fractured os calcis.

The authors report their experience with 3D computed tomography (CT) in 23 patients with fractured os calcis (several types of fractures) in comparison to classical 2D CT. The diagnostic accuracy was not found to be improved by the three-dimensional representation. 3D CT is affected by reconstruction artifacts and strongly depends on the choice of threshold. However the 3D visualization is appreciated by the surgeons.

Adult↗
PubMedDate not supplied

CT and MRI of Gorham syndrome.

Gorham syndrome, also known as massive osteolysis or vanishing bone, is a rare disorder (135 cases reported) leading to extensive loss of bony matrix, replaced by proliferating thin-walled vascular channels. Three histologically proven cases of the disease are reported, including the clinical presentation and modern imaging features with CT (with 3D reconstruction) as well as T1- and T2-weighted MRI. Two cases in young women were located in the pelvis with extensive osteolysis reaching to the acetabulum. The third case in a 2-month-old boy is the youngest case ever reported and involved the humerus. The radiological appearance of the disease is discussed and the importance of the modern imaging methods debated.

Acetabulum↗