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Biomedical subjects

J P Cottier

Publications and source records attributed to J P Cottier.

At least 37 records · Page 2Linked to original sources
PubMed2000

Observations on metal concentrations in three species of shark (Deania calcea, Centroscymnus crepidater, and Centroscymnus owstoni) from southeastern Australian waters.

Deep sea dog sharks (Deania calcea, Centroscymnus crepidater, and Centroscymnus owstonii) were captured from the waters off western Victoria, Australia, in April and May 1998. The elements As, Ca, Cd, Cu, Fe, Hg, K, Mg, Mn, Na, Sr, and Zn were detected in the muscle tissue. The concentrations of Al, Ba, Be, Cr, Mo, Ni, Pb, and V were below the detection limits of the instrumental techniques employed (ICP-ES and GF-AAS). However, significant concentration differences between species were detected for As, Cd, Hg, and Zn. C. owstoni contained the highest concentrations of each of these elements. The concentrations of Cu, Pb, and Zn in each species were below the maximum levels permitted in food by the Australian Food Standards Code. The maximum permitted concentrations of As and Hg were exceeded in all species, and weekly consumption of 400 g of any of these sharks would result in intake of more than the FAO's provisional tolerable weekly intake. Although C. crepidator and D. calcea have strong relationships between length and mercury concentration, C. owstoni does not. Placing C. crepidator and C. owstoni in the same genus, therefore, is worth re-examination as the mechanisms for controlling mercury in C. owstoni appear to differ from that used by both C. crepidator and D. calcea.

Animals↗
PubMed2000

Cavernous sinus invasion by pituitary adenoma: MR imaging.

PURPOSE: To define magnetic resonance (MR) imaging criteria for the diagnosis of cavernous sinus invasion by pituitary adenoma. MATERIALS AND METHODS: The MR images obtained in 106 patients (86 female, 20 male; age range, 16-71 years) were reviewed retrospectively by two physicians. The standard-of-reference criteria for invasion were the surgical findings. A chi(2) analysis was performed, and the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for nine groups of MR imaging signs were computed. RESULTS: Invasion of the cavernous sinus was certain (PPV, 100%) if the percentage of encasement of the internal carotid artery (ICA) by tumor was 67% or greater. It was highly probable if the carotid sulcus venous compartment was not depicted (PPV, 95%) or the line joining the lateral wall of the intracavernous and supracavernous ICAs was passed by the tumor (PPV, 85%). It was definitely not invaded (NPV, 100%) if the percentage of encasement of the intracavernous ICA was lower than 25% or the line joining the medial wall of the intracavernous and supracavernous ICAs was not passed by the tumor. CONCLUSION: The radiologic diagnosis of cavernous sinus invasion by pituitary adenoma remains difficult, but the above-mentioned criteria may be of assistance.

Adenoma↗
PubMed2000

Uterine artery embolization in the primary treatment of uterine leiomyomas: technical features and prospective follow-up with clinical and sonographic examinations in 58 patients.

OBJECTIVE: The purpose of this study was to analyze the technical features of uterine artery embolization and to evaluate the effectiveness of this method as the primary treatment of uterine leiomyomas in a series of 58 patients monitored by clinical and sonographic examinations. SUBJECTS AND METHODS: Fifty-eight women (age range, 33-65 years; mean age, 44.5 years) with symptoms caused by uterine leiomyomas (abnormal bleeding, bulk-related symptoms, pelvic pain) were included in this prospective study. We performed embolization with a single catheter using the single-femoral artery approach, injection of particles (150-250 mm), and an absorbable gelatin sponge. Postprocedural pain was assessed using a visual analog scale. Systematic follow-up included clinical and sonographic examinations at 3 months for 58 patients, at 6 months for 46 patients, at 1 year for 27 patients, and at 2 years for seven patients. RESULTS: Embolization was performed without problems in 84% of the patients. Post-procedural pain control was excellent in 90% of the patients. In most patients, symptoms were improved or had resolved at 3 months (90%), 6 months (92%), and 1 year (93%), and all patients were symptom-free at 2 years. Clinical failure of treatment occurred in only two patients (3%). Progressive reduction in leiomyoma size was revealed during sonographic follow-up, and new leiomyomas were seen in one patient at 2 years. CONCLUSION: Uterine artery embolization is an endovascular method for the treatment of uterine leiomyomas that is clinically effective in most patients and that induces a progressive reduction in the size of the largest leiomyomas.

Adult↗
PubMed2000

[MRI diagnosis of cavernous sinus invasion by pituitary adenomas].

Several MRI signs are helpful for the preoperative MRI diagnosis of cavernous sinus invasion by an adenoma. The first step is to analyse the percentage of encasement of the intracavernous ICA by the adenoma. If this percentage is greater than or equal to 66%, the cavernous sinus is invaded. If the percentage of encasement of intracavernous CA is less than 25%, the cavernous sinus is not invaded. If the percentage of encasement is between 25 and 66%, the analysis of the cavernous venous compartment, the drawing of intercarotid lines and the analysis of the shape and venous compartments of the cavernous sinus are necessary. The cavernous sinus invasion remains very likely if the carotid sulcus venous compartment is obliterated, or if the lateral intercarotid line is crossed. Conversely, if the median intercarotid line is uncrossed, the superior venous compartment is visible, the cavernous sinus is of normal size, or there is no bulging of its lateral dural wall, invasion of the cavernous sinus space can reliably be excluded.

Adenoma↗
PubMed1999

Failure to demonstrate a direct caroticocavernous fistula due to arterialisation of the ipsilateral cavernous sinus.

We report a woman in whom a small direct caroticocavernous fistula (DCCF) was revealed after successful transarterial occlusion of a contralateral fistula which drained into both cavernous sinuses. We underline that a second smaller fistula can be masked by a contralateral larger one due to the lack of pressure gradient between the internal carotid artery (ICA) and arterialised blood in the ipsilateral cavernous sinus. We suggest that bilateral ICA angiograms should be performed before and after occlusion of all DCCF.

Aged↗
PubMed1999

Effects of the method of drawing regions of interest on the differential diagnosis of extrapyramidal syndromes using 123I-iodolisuride SPET.

Various parameters are currently used for the semi-quantitative assessment of dopamine D2 receptors and differ according to the delineation of the striatal region of interest (ROI) and the choice of the reference ROI. The aim of this study was to assess the value of different ROI approaches in differentiating patients with normal or increased numbers of D2 dopamine receptors (group 1 = Parkinson's disease, n = 8) from patients with decreased dopamine D2 receptors (group 2 = other extrapyramidal syndromes, n = 9) using 123I-iodolisuride SPET (ILIS-SPET). 123I-iodolisuride (190 +/- 31 MBq) and 99Tcm-ethyl cysteinate dimer (99Tcm-ECD) perfusion SPET were performed in the same position, with a dual-headed gamera camera equipped with fan beam collimators. Both a geometric approach (ellipse, circle or rectangle) and an anatomical approach using the CT scan and perfusion SPET as anatomical guides were used to draw striatal and reference ROIs. A total of 33 different parameters were calculated for each patient, indicating the ratio of counts between the striatal and reference ROIs (frontal, occipital cortex or cerebellum) and the asymmetry between the right and left striatum. More significant differences between group 1 and group 2 were found by using geometric ROIs than by using anatomical ROIs. The most discriminant ratios were the caudate/occipital, caudate/frontal and striatum/occipital ratios (P = 0.001, P = 0.002, P = 0.003 respectively). A close correlation was found between the striatum/caudate and striatum/occipital ratios, but not between the striatum/frontal and striatum/occipital ratios or between the striatum/frontal and striatum/caudate ratios. We conclude that the occipital cortex is the best reference for the semi-quantitative evaluation of dopamine D2 receptors as the frontal cortex could include some dopamine D2 receptor-bound radioligand, and that the caudate/occipital ratio is an appropriate parameter for differentiating Parkinson's disease from non-Parkinson extrapyramidal syndrome by 123I-iodolisuride SPET.

Adult↗
PubMed1999

Hemianopsia related to dissection of the internal carotid artery.

Spontaneous dissection of the internal carotid artery is typically associated with cerebral vascular infarction along the anterior and middle cerebral distribution, whereas occipital infarction is usually related to posterior circulation abnormalities. Hemianopsia with occipital infarction related to carotid artery dissection has therefore rarely been reported. A 40-year-old woman in whom acute-onset hemianopsia developed, related to occipital infarction secondary to internal artery dissection, is described. This atypical association is explained by anatomic variations of the posterior part of the circle of Willis. Neuroimages showed occipital infarction related to internal carotid artery dissection associated with hypoplasia of the proximal portion of the cerebral posterior artery (P1). The anatomic correlation of this atypical association and a review of the literature are presented.

Adult↗
PubMed1998

Radiation-induced optic neuropathy 4 years after radiation: report of a case followed up with MRI.

We report a case of radiation-induced optic neuropathy in a 32-year-old man with Cushing's disease and a recurrent tumour of the left cavernous sinus. The patient experienced rapid, painless loss of vision 4 years after treatment without recurrence of tumour or other visual disorder. MRI showed enlargement and contrast enhancement of the optic chiasm. A year later the patient was almost blind and MRI showed atrophy and persistent contrast enhancement of the chiasm.

Adenoma↗
PubMed1998

Bilateral olivary hypertrophy and palatal myoclonus.

We report on a case of palatal myoclonus associated with olivary hypertrophy on magnetic resonance imaging (MRI) in a 63-year-old man. This rare radiological finding must be differentiated from a brainstem tumor.

Brain Neoplasms↗
PubMed1998

[MRI diagnosis of sinus cavernous invasion by pituitary adenomas].

PURPOSE: To evaluate the preoperative MRI criteria of a sinus cavernous invasion by a pituitary adenoma. MATERIAL AND METHODS: Study of 102 cavernous sinuses among 51 patients who had had a surgical cure of pituitary adenoma. Thirteen patients had a surgical invasion of the cavernous sinus. RESULTS: A certain number of signs eliminated cavernous sinus invasion. The best means consisted in not crossing the intercarotid line (Sensitivity-Se = 100%, Specificity-Sp = 85% and Negative Predictive Value-NPV = 100%). The others means implied: not going past twelve o'clock on the internal carotid artery-ICA (NPV = 97.1%), symmetrical size of the cavernous sinus (NPV = 92.5%), non-convexity of the lateral wall (NPV = 90.2%), visualization of at least two venous groups of the laterosellar space (NPV = 90.2%) and finally, non-displacement of the ICA (NPV = 89.2%). The best criteria for diagnosis were passing by the intra and supracavernous ICA lateral tangent (Se = 84.6%, Sp = 95%) and the percentage of ICA encasement by the adenoma exceeding 25% (Se = 92.3%, Sp = 85%). CONCLUSION: Except the total encasement of the intracavernous ICA, the cavernous sinus can be invaded when the lateral tangent of the supra and the intracavernous ICA is crossed, and also when the percentage of ICA encasement exceeds 25%.

Adenoma↗
PubMed1998

[Comparison of three fat suppression sequences for the detection of vertebral detection. Turbo STIR, phase contrast gradient-echo, and MISTEC-Chopper after gadolinium injection].

OBJECTIVES: Assess three fat suppression sequences used to search for spinal metastases: TurboSTIR, phase contrast gradient-echo, and MISTEC-Chopper after gadolinium injection. MATERIAL AND METHODS: A prospective study was conducted in 10 patients with primary neoplasia. MIR sequences acquired (1 Tesla) were TurboSTIR, T1 spin-echo with and without gadolinium injection, phase contrast gradient-echo and M-Chop after gadolinium injection. Signal intensity in normal bone marrow, metastatic tissue, and subcutaneous fat as well as background noise was measured. Signal-to-noise (S/N) ratio was determined. Lesion borders, artefacts, and extent of detected lesions were determined quantitatively. Bone marrow signal intensity was also recorded. RESULTS: S/N ratio was best with gradient-echo which identified well the borders of lesions within the hemopoietic marrow. For lesions located in high-fat marrow (as in post-radiation marrow), the high intensity signal of the lesion confounded with the fat signal. TurboSTIR gave effective fat signal suppression and was particularly useful for yellow marrow, less so for red marrow. This technique confounded cell proliferation with perilesional edema (enlarging lesion extention). In one case, this sequence did not detect a small lesion visible with the two other sequences. This sequence was sensitive to artefacts (especially vascular artefacts) which can produce false nodular images. M-Chop gave good suppression of vertebral fat tissue (better for yellow marrow) but subjective detection of lesions was more difficult. CONCLUSION: The phase contrast gradient-echo sequence after gadlinium injection appeared to be the best sequence excepting cases of post-trauma (radiotherapy or chemotherapy) fat transformation of the marrow where the TurboSTIR sequence could be preferred.

Adipose Tissue↗
PubMed1997

[Cerebral achromatopsia without prosopagnosia, alexia, object agnosia].

A 62-year-old woman was admitted for a disorder of color vision. This cerebral achromatopsia was isolated, without prosopagnosia, alexia, object agnosia. MRI showed bilateral temporo-occipital infarcts, including lingual and fusiform gyrus. Neuropsychological examination and topographic hypotheses are discussed.

Color Perception↗
PubMed1996

[MRI and computer-assisted tomography in Kufs disease. Apropos of a familial form].

Kufs disease is the adult form of ceroid neurolipofuscinosis, and an uncommon cause of degenerative nervous system disease affecting young adults. We present here 4 cases of family form revealed by a demential syndrome. In all 4 patients MRI showed diffuse cortical atrophy predominant in the parietal regions. In 3 of these 4 patients MRI also exhibited a low signal in T2-weighted sequences on the putamens. There was no abnormality of the white matter. Diagnosis was made by cerebral biopsy in one case and by rectal biopsy in all other cases. Although the MRI images are not specific, they must be used when the diagnosis of Kufs disease is suspected in young patients with demential syndrome.

Adult↗
PubMed1996

[Primary intramedullary melanoma. Apropos of a case].

Primary melanoma is a rare spinal tumour first reported by Hirschberg in 1906. Since then, only 34 cases have been reported. When present here a new case of primary intramedullary thoracic melanoma developed in a 64-year old male patient. MRI showed a paramagnetic signal with reactive cysts. Macroscopy and histology confirmed the diagnosis. Spinal cord melanoma is presumed to be primary when no other melanoma is found outside the CNS. The tumour is often located in the middle or lower thoracic cord, may be intra- or extra-medullary and leptomeningeal or extradural. It frequently progresses slowly. MRI is the essential examination as it demonstrates a lesion with paramagnetic properties. Its image is not specific and may correspond to other pigmented tumours (meningeal melanocytoma, melanotic schwannoma), to a lipoma or to a vascular or tumoral haemorrhagic lesion. Treatment is uncertain, but surgery is frequently associated with radiation. Postoperative follow-up aims at detecting a local regrowth of the tumour or leptomeningeal dissemination which affects the prognosis.

Diagnosis, Differential↗
PubMed1996

[Use of a stimulated echo sequence in the MRI study of the brain and spine].

We describe in this paper how the STEAM sequence can be an efficient tool to obtain images free of flow artifacts in anatomical situation where the spin echo failed. The simplest way to eliminate flow artifacts is to exploit the dephasing induced by motion in magnetic field gradients and to reduce to zero the signal from moving tissues. This can be achieve by increasing the time elapsed between the spin excitation and the signal observed. Because of T2 relaxation, such an increase results in a signal decrease when the spin echo sequence is used. The STEAM sequence has the unique property that the time elapsed between observation and excitation can be increased without change in T2 value and so allows a good suppression of signals from the moving spins with short TE. Our results demonstrate that, although the stimulated echo intensity is only half that of a spin echo taken at the same read out time, the advantages of STEAM imaging can compensate for this partial loss in signal to noise in some particular clinical situations. The influence of mixing time on contrast has been evaluated using thoracic spine imaging and it has been shown that contrast between spine and CSF can be significantly improved (+ 60%) when TM is increased (from 17 ms to 50 ms). In the same time, the contrast between spine and fat issue decreases (40%). This last effect facilitates the adjustment of contrast window. Suppression of motion artifacts has first been evaluated with thoracic spine imaging, using a whole body coil. Suppression of artifacts was better than that obtained with a flow compensated spin echo sequence, especially in the case of kyphotic patients when a presaturation band was inefficient. In a second step suppression of motion artifacts has been evaluated from posterior fossa examination after injection of a paramagnetic contrast agent. The images obtained with the stimulated echo sequence show a dramatic reduction of signal from blood in the lateral sinus, and therefore an increase of quality by elimination of motion artifacts.

Adipose Tissue↗
PubMed1995

Endometriosis of the sciatic nerve: case report demonstrating the value of MR imaging.

Among the many causes of sciatica, endometriosis, a rare aetiology, should be considered in menstruating women in view of the diagnostic strategy and ensuing therapeutic implications. We report a case of sciatic nerve involvement with endometriosis in contact with the nerve in the left sciatic notch. Exploration by MRI was invaluable for the diagnosis, revealing a signal on the stem of the nerve suggestive of a lesion with haemorrhagic content.

Adult↗