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Biomedical subjects

D Doyon

Publications and source records attributed to D Doyon.

At least 73 records · Page 4Linked to original sources
PubMed1989

[Diagnosis of diseases of the spinal cord and the vertebral column].

Magnetic resonance imaging (MRI) nowadays plays a predominant role in the diagnosis and evaluation of spinal canal pathologies and has reduced the other exploratory methods, including computerized tomography (CT) and myelography, to an ancillary role. These pathologies are divided into three groups: those where MRI is the only imaging method (syringomyelia, tumours in the spinal canal, phakomatoses, external pachymeningitis, spinal cord injuries, myelitis); those where MRI is the initial method and is completed by other examinations (vascular malformations, dysraphism, myelopathies due to cervical osteoarthritis) and those where MRI still play a lesser role than CT (degenerative lesions of the lumbar column).

Humans↗
PubMed1989

Magnetic resonance investigations of non-acoustic petrous lesions.

Twenty cases of intrapetrous lesions were studied by a 1.5 T magnetic resonance (MR) unit. In all cases, comparisons were made between MR, CT and clinical findings. Our present material included 9 cholesteatomas, 1 cholesterol cyst, 3 primary epidermoid carcinomas, 2 metastatic neoplasms, 1 glomus jugulare tumor and 4 facial neurinomas. Gadolinium was injected in 7 cases and seemed to be the best method for studying the intrapetrous tumors. MR permitted accurate topographic study and assessment of tumoral extension, as well as a ready demonstration of tumor vascularity. The present findings also showed that MR is not capable of defining small bony detail or calcifications.

Adolescent↗
PubMed1989

[MRI in the diagnosis of recurrent cholesteatoma of the petrous bone].

Nine cases of recurrent petrous cholesteatomas have been studied by a 1,5 T MR unit. Gadolinium was injected in 1 case. In all cases, comparison between MR, CT and clinical findings were made. MR allows for accurate topographic study and assessment of cholesteatomas extension, in particular in the posterior fossa and skull base. Relationships with the internal carotid artery and the jugular vein are clearly depicted.

Adult↗
PubMed1988

MRI features of craniopharyngiomas at 1.5 Tesla. A series of 13 cases.

Thirteen patients with craniopharyngioma were explored with a 1.5 Tesla magnetic resonance imager. The results were compared with those of CT and with operative findings. The MRI signals were correlated with the biochemical composition of the cysts (proteins, lipids, iron, LDH) in 5 cases; 2 patients were studied after an intravenous injection of gadolinium DOTA. MRI proved vastly superior to CT to evaluate the spread and identify the various components of craniopharyngiomas (cysts, fleshy parts, haemorrhages), except for calcifications. Gadolinium improved the detection of fleshy parts and "active" cysts. The signals emitted by cysts were extremely variable on T1-weighted sequences. The correlation between MRI and biochemical data was complex, but it appeared that protein, lipid and iron concentrations had a major influence on cyst signals. MRI with gadolinium may be envisaged as first-line examination to improve the evaluation of spread, determine the prognosis and detect recurrences of craniopharyngiomas. CT could be reserved to difficult cases with invasion of bones and sinuses.

Adolescent↗
PubMed1987

Comparative trial of Hexabrix (320 mg iodine/ml), iohexol (300 mg iodine/ml) and iopamiron (300 mg iodine/ml) in cerebral and spinal angiography: a preliminary report.

A comparison has been carried out of results of cerebral and spinal-cord angiography with two non-ionic contrast media, iohexol and Iopamiron, and a low-osmolality contrast medium, Hexabrix. A comparative study of iohexol, Hexabrix, and Iopamiron was carried out in a first group of 41 patients, and Hexabrix was compared with Iopamiron in a second group of 56. Evaluation criteria included local and general safety, as well as quality of angioscopy and angiography. In the first group of patients there were no significant differences in safety between the three agents. On the other hand, quality of visualisation during angioscopy with Hexabrix was clearly better. In the second group, safety and quality of the radiographic images were identical; however, once again, quality of angioscopy was better with Hexabrix than with Iopamiron. We conclude that Hexabrix appears to be the best opacifying agent currently available for cerebral and spinal-cord angiography. While results with Iopamiron were quite similar, the latter agent is slightly more expensive.

Cerebral Angiography↗
PubMed1987

[Complications of the dilatation of Stensen's duct: stenosis and lithiasis].

A recent publication noted the apparent lack of serious complications of dilatation of salivary canals, based on a review of 16 cases. This is contested by the report of three cases of dilatation of Stensen's duct complicated by lithiasis and stenosis, with associated canalar pseudo-cysts. Surgical excision was required and allowed study of histopathology of this affection.

Adult↗
PubMed1987

[Are auditory prostheses a contraindication to magnetic resonance imaging?].

Prior to the use of nuclear magnetic resonance imaging (NMRI) in patients with metallic ossicular prostheses their compatibility must be investigated with the intense magnetic fields generated by NMRI. Implanted auditory prostheses are an absolute contraindication to NMRI, but an experimental study of its possible interaction with metallic stapedial prostheses has shown absence of their displacement. The artefact induced may alter images of middle ear but do not affect internal auditory canal. Nevertheless, manufacturers should conduct tests of magnetism of prostheses before they are passed as satisfactory.

Cochlear Implants↗