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Biomedical subjects

P Halimi

Publications and source records attributed to P Halimi.

At least 37 records · Page 2Linked to original sources
PubMed1993

Internal architecture of the parotid gland at MR imaging: facial nerve or ductal system?

A radiologic-anatomic study was performed to determine the nature of the low-signal-intensity curvilinear structures currently seen in the normal parotid gland on axial T1-weighted magnetic resonance (MR) images. These structures are considered by some to represent the intraparotid facial nerve. After cannulation of the Stensen duct, the authors imaged the parotid gland of two cadavers in situ before and after intraductal injection of gadolinium tetrazacyclododecanetetraacetic acid. Retrograde filling was obtained in one gland. The same sections were used throughout a subsequent anatomic study, allowing correlation of the MR findings with the macroscopic and histologic appearance of the gland. Comparison of MR images and gross and histologic sections established that two intraparotid facial nerve segments, although identified from the histologic study, were not visible on corresponding MR images. Many areas of low signal intensity seen within the gland were found to represent the main duct and some afferent ductal branches.

Cadaver↗
PubMed1993

[Does the use of nasal vasoconstrictor agents change tomodensitometric images of nasosinusal polyposis?].

This study compared the results of the CT scan of the paranasal sinuses in nasal polyposis patients before and after a topical vasoconstrictor application on the nasal mucosa. No change have been observed either on the maxillary and ethmoidal sinuses, or the middle meatus. On the other hand, an important retraction was observed on the nasal mucosa, in particular on the inferior turbinate. Then, the application of a topical vasoconstrictor on the nasal mucosa does not seem necessary in order to explore the sinuses in patients with nasal polyposis.

Adult↗
PubMed1992

[Is facial nerve visible on magnetic resonance imaging?].

The internal architecture of the parotid gland was studied by nuclear magnetic resonance (NMR) imaging, particular attention being paid to the intra-parotid portion of the facial nerve. Currently available apparatuses provide high resolution images of previously poorly elucidated anatomic details. Certain authors consider that images in the axial plane in T1 allow direct visualization of the facial nerve and its branches in the form of low frequency linear signals within the gland. The present study, based on radio-anatomic correlations and date determined in a healthy volunteer, demonstrated that these structures correspond in fact to segments of the excretory canal tree, the facial nerve and its branches being invisible on NMR imaging. It is not possible, therefore, to determine the location of a parotid tumor in relation to these nerve elements using this imaging technique.

Facial Nerve↗
PubMed1992

[Nasal and sinusal polyposis. Semiology and values of magnetic resonance imaging].

Twelve patients with nasal polyposis were examined with magnetic resonance imaging (MRI) prior to surgical ethmoidectomies (20 ethmoidectomies). MRI signal was analyzed in correlation with surgical findings in order to define the semiology of nasal and sinuses polyps. One of the most important point of this semiology is based on the analysis of sequences after administration of gadolinium. MRI seems an interesting method for analysing the extension of nasal polyposis and could be useful for ENT surgeons before an endoscopic nasal surgery.

Adolescent↗
PubMed1992

[Severe iatrogenic hyponatremia in a pregnant woman].

Severe hyponatremia may be associated with several complications leading sometimes to the death of the patient. We present the case of a healthy young pregnant woman who developed a severe acute iatrogenic hyponatremia (120 mEq.l-1). The treatment of the acute dehydration due to hyperemesis gravidarum led to a dilutional hyponatremia. The causes, complications and management of severe acute hyponatremia are discussed.

Acute Disease↗
PubMed1991

Anterior and posterior hypopituitarism with pituitary stalk abnormalities.

Hypopituitarism and diabetes insipidus are often idiopathic conditions. A retrospective study of 6 cases of diabetes insipidus and 8 cases of partial or global idiopathic anterior hypopituitarism has shown that MRI is of considerable value to detect abnormalities of the pituitary stalk or hypothalamo-pituitary "relay". On the basis of MRI findings, some cases of idiopathic hypopituitarism can now be grouped together in a new entity which may be called hypopituitarism due to neonatal transection of the pituitary stalk.

Adolescent↗
PubMed1991

[The normal cranial nerves in MRI. Description and visualization frequency].

In order to assess the value of MR in the depiction of intracranial nerves, we retrospectively reviewed 60 patients investigated over a period of 2 years. The aim of this study was: 1) to assess the score of MR in the detection of cranial nerves III to XII; 2) to determine accurate landmarks allowing for easy detection of those cranial nerves. Cranial nerves III, V, VII, VIII are well seen (70 to 100%), very often in both axial, sagittal and coronal sections. Nerves IX to XII are correctly studied only on axial planes [81 and 83%), but it is difficult to distinguish between the vagal nerve and the glossopharyngeal and spinal nerves. Due to their oblique direction and small size, fourth and sixth nerves are rarely visualized. The more important landmarks are the chiasma, the colliculi, the Meckel's cave, the internal auditory canal, the jugular foramen, the hypoglossal canal and the different brainstem structures. We suggest the following scanning protocol: short spin echo sequences (TR = 600 ms, TE = 20 msec), 3 to 5 continuous sections, 16 to 20 cm field of vue with respectively 4 or 2 excitations, 256 x 256 matrix, with at least one acquisition plane (axial), but preferably two or three planes. Thus MR is sensitive exam in the recognition of cranial nerves, and it must be the first step exam in patients presenting with cranial nerve disease.

Adult↗
PubMed1990

Occult cerebrovascular malformations: follow-up with MR imaging.

The clinical and magnetic resonance (MR) imaging findings in 20 patients with MR evidence of occult cerebrovascular malformations (OCVMs) were retrospectively analyzed. Of 27 lesions followed up throughout a mean period of 18 months, eight showed obvious evolution on MR images (four cases of regression and four cases of new bleeding). Three new independent lesions were disclosed. Clinical evolution was discordant with MR findings in five patients. In the other patients, topography of the lesion, mass effect, and location of the hemorrhage could explain clinical data. The dynamic nature of OCVMs must be considered in decisions on therapeutic management.

Adult↗
PubMed1990

[Physico-chemical properties of 4 endodontic sealing cements].

Four endodontic sealers were compared with two series of tests, in thin layer and in 10 mm long and 5 mm diameter rods. Under these conditions, the Pulp Canal Sealer showed the best ability to present a thin layer and the same flow than the Cortisomol. Its setting time was 15 minutes. Forty-eight hours later, the Sealite showed a very good tightness compared to the other sealers. At 30 days, the Pulp Canal Sealer and the OZn-Eugénol were the tightest ones. Less water was absorbed with the Cortisomal and the Sealite. Is there, for these sealers, any correlation between water-absorbtion and tightness?

Absorption↗
PubMed1990

Visibility of cranial nerves at MRI.

In order to assess the value of MRI in the depiction of intracranial nerves, we retrospectively reviewed 60 patients investigated over a 2-year period. The purposes of this study were: 1) to determine the score of MRI in detecting cranial nerves III to XII, and 2) to establish accurate landmarks for easy detection of these nerves. Cranial nerves III, V, VII and VIII are well seen (70 to 100%), very often on axial, sagittal and coronal sections. Nerves IX to XII are correctly studied only on axial planes (81 and 83%), but it is difficult to distinguish between the vagus nerve and the glossopharyngeal and spinal nerves. Due to their oblique direction and small size, nerves IV and VI are seldom visualized. The most important landmarks are the chiasma, the colliculi, Meckel's cavity, the internal auditory canal, the jugular foramen, the hypoglossal canal and the brainstem structures. We suggest the following scanning technique: short spin-echo sequences (TR 600 ms, TE 20 ms), 3 to 5 mm thick contiguous sections, 16 to 20 cm field of view with 4 or 2 excitations respectively, 256 x 256 matrix, and at least one acquisition plane (axial plane), but preferably two or three planes. MRI is a sensitive examination in the recognition of cranial nerves. It should be the first-step exploratory procedure in patients with cranial nerve pathology.

Adolescent↗
PubMed1990

[Severe lesions of the petrous bone caused by pseudomonas aeruginosa].

Pseudomonas aeruginosa is often isolated in infections of the ear cleft. In some circumstances, this organism can cause serious petrous or peri-petrous lesions. Two pictures are seen: Malignant external otitis with severe headaches, signs of external otitis, and usually pseudomonas aeruginosa is isolated. This is usually seen in an elderly diabetic patient. Nerve paralysis is the main risk. The other complications, very grave in the past, are rare nowadays with the use of selective antibiotic treatment. Pseudomonas aeruginosa is also the causative organism in extensive osteitis of the skull base. Diagnostic problems are seen in case of specific infections or tumoral lesions. The treatment includes the same medications as for the malignant external otitis, as well as complete surgical excision.

Aged↗
PubMed1990

[Computerized electroencephalographic monitoring in anesthesia].

The computerized electroencephalogram monitor provides a simple interpretation of the standard EEG trend. In the operating room, this compact EEG monitor is convenient and the trend is easy to read for a non-specialist user. EEG monitoring is especially indicated in carotid endarterectomy for the detection of ischemic event during surgery. The use of this monitor should be recommended for high risk patients (cardiac surgery, cerebral aneurysm surgery, controlled hypotension) to determine the adequate depth of anesthesia and to perform a stress-free anesthesia when the anesthetic drug is given by titration according to the decrease in the awakening electrical cerebral activity.

Anesthesiology↗
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↗