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Biomedical subjects

V Bousson

Publications and source records attributed to V Bousson.

26 records · Page 2Linked to original sources
PubMed1998

[Artifacts in magnetic resonance angiography].

Magnetic resonance angiography (MRA) has become a major tool in the management of vascular diseases. However, many artifacts that may lead to misinterpretations are encountered with this imaging modality. The purpose of this paper was to enumerate, explain and illustrate each kind of artifact encountered with "time of flight" or "phase contrast" imaging methods. For each artifact, we tried to provide one or several techniques to minimize its consequences.

Artifacts↗
PubMed1996

Preoperative portal vein embolization for extension of hepatectomy indications.

To render hepatectomy feasible in patients with an initially deficient volume of the future remnant liver (FRL), we redistributed portal blood flow rich in hepatotrophic substances toward the FRL. Redistribution was achieved with preoperative portal vein embolization (POPE) feeding the future resected liver. POPE was performed in 31 patients, under fluoroscopic guidance, via a percutaneous access. POPE was well tolerated and surgery was practicable in 24 patients without severe postoperative liver failure. Seven operations were cancelled, but only one due to insufficient hypertrophy of the FRL. FRL volume values were 90 to 560 mL (mean 260 mL) before POPE and 160-783 mL (mean 443 mL) after POPE, which represents a median increase of 79% +/- 50%. Hypertrophy of the FRL was 90% +/- 52% after 30 days with cyanoacrylate, 53% +/- 6% after 43 days with Gelfoam, and 44% +/- 30% after 35 days with coils. Slight shrinkage was obtained in the volume of the embolized liver, for which resection was planned. Overall survival was 2-62 months (mean 26 months), disease-free survival was 0-60 months (mean 19 months), and 7 patients are disease-free and alive 14 to 60 months (mean 43 months) after surgery. Although exclusively applicable in a limited subset of patients, POPE widens the possibilities of curative hepatectomies, because it induces sound hypertrophy of unembolized liver segments. Cyanoacrylate seems to ensure better and faster hypertrophy.

Adolescent↗
PubMed1995

[Post-radiation necrosis of the cricoid cartilage: an uncommon case].

Radiation therapy is considered as the treatment of choice for early stage laryngeal cancer. However, a few patients, after several years, develop severe life threatening complications, like edema or chondronecrosis. The clinical examination or endoscopy follow up may be difficult. CT and MR imaging can show the exact diagnosis depicting exquisitely the anatomy of the larynx. But at the beginning, the abnormalities are radiographically subtle and their diagnosis may be difficult because of artefacts due to patient dyspnea and mucous secretions. The main suggestive imaging features for suspecting a chondronecrosis seem to be the lost of normal signal hyperintensity on T1 MR imaging or a focal lack of cortical bone on CT scans, just adjacent to a focal swelling of the pharyngo-larynx mucosa. The barium pharyngography remains the best imaging diagnosis procedure for depicting associated abnormal communication between the digestive tract and the adjacent spaces or the cartilages of the larynx. Therefore, when the diagnosis is delayed, only salvage total laryngectomy can stop the infectious process. We report one case of a cricoid cartilage chondronecrosis eleven years after radiation therapy for laryngeal cancer.

Cricoid Cartilage↗
PubMed1995

[Anatomy of the circle of Willis with 3D time of flight magnetic resonance angiography and analysis of partitions].

The purpose of this study was to analyse with 3D TOF MR angiography the anatomical variants of the circle of Willis (CW) in 109 consecutive patients. In all cases, the quality of exams was sufficient to analyse the anatomy of CW. Nevertheless, MRA over estimated hypoplastic segments because incomplete CW were more frequently demonstrated with MRA than in anatomic literature. This lack of MRA sensitivity was related to artifacts as MIP artifacts and blood flow artifacts. MRA sensitivity was improved by analysis of partitions with MIP reconstructions.

Aged↗
PubMedDate not supplied

A method of radio-frequency inhomogeneity correction for brain tissue segmentation in MRI.

An automatic method of correcting radio-frequency (RF) inhomogeneity in magnetic resonance images is presented. The method considers that image intensity variation due to radio-frequency inhomogeneity contains not only low frequency components, but also high frequency components. The variation is regarded as a multiplication of low frequency (capacity variation of coil) and the frequency of object (true image). The efficiency of the proposed method is illustrated with the aid of both phantom and physical images. The impact of the inhomogeneity correction on brain tissue segmentation is studied in detail. The results show significant improvement of the tissue segmentation after inhomogeneity correction.

Brain↗
PubMedDate not supplied

De novo reconstruction of functional bone by tissue engineering in the metatarsal sheep model.

Large bone defects are still a challenge to orthopedic surgeons. In this study, a massive bone defect with a clinically relevant volume was efficiently reconstructed by transplanting an engineered bone in which mesenchymal stem cells (MSCs) expanded in autologous serum (AS) were combined with a porous scaffold. In the first step, we established that the way in which the MSCs are distributed over the scaffold affects the ultimate bone-forming ability of the transplant: constructs consisting of a natural coral scaffold and a pseudo-periosteal layer of MSCs surrounding the implant (coral-MSC3D) formed significantly more bone than constructs in which the MSCs were distributed throughout the implant (p = 0.01). However, bone healing occurred in only one sheep, owing to the high resorption rate of natural coral scaffold. To overcome this problem, constructs in which MSCs were combined with a porous coralline-based hydroxyapatite (CHA) scaffold having the same architecture as natural coral but a lower resorption rate were prepared. After their implantation, these constructs were found to have the same osteogenic potential as autologous bone grafts in terms of the amount of newly formed bone present at 4 months (p = 0.89) and to have been completely replaced by newly formed, structurally competent bone within 14 months. Nevertheless, although the rate of bone healing was strikingly improved when CHA-MSC3D constructs were used (five of seven animals healed) as compared with the coral-MSC3D construct (one of seven healed), it was still less satisfactory than that obtained with autografts (five of five healed).

Animals↗
PubMedDate not supplied

Intractable hiccups: the role of cerebral MR in cases without systemic cause.

PURPOSE: To look for central nervous system abnormalities as possible causes of intractable hiccups. METHODS: Of a series of 50 patients with chronic (ie, lasting more than 48 hours) hiccups, a prospective study identified a subgroup of 9 patients with no clinical or gastroesophageal abnormalities (according to endoscopy, pH monitoring and manometry). We performed in all 9 patients brain and upper cervical cord MR examination with precontrast and postcontrast T1- and T2-weighted sequences. A study of the last cranial nerves was done with thin T2-weighted imaging (constructive interference in a steady state sequence). The cervical cord and parapharyngeal space were systematically explored using coronal T2- and sagittal T1-weighted imaging. RESULTS: Five of these 9 patients had definite MR abnormalities located in the temporal lobe (3 cases), cerebellopontine angle (1 case), or areas of high signal intensity compatible with demyelination (1 case). The relationship between hiccups and infratentorial abnormalities in 2 cases was doubtful (vascular loop and prominent posterior condylar canal). MR findings in 2 cases were considered normal. CONCLUSIONS: Brain MR is a useful investigation in patients with chronic hiccups when gastroesophageal lesions are either excluded or too mild to account for an intractable hiccup.

Adult↗