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Biomedical subjects

F Cattin

Publications and source records attributed to F Cattin.

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

[Ultrasound contrast agents].

Ultrasound contrast agents are introducing a new vision to ultrasonography. The increase in the Doppler signal intensity improves difficult examinations. Technical failures in the study of transcranial, liver and renal vessel might be rescued with the injection of these new compounds. The introduction of specific image sequences such as harmonic imaging and pulse inversion imaging allows detection of parenchymal enhancement in liver and renal examinations. The injection of ultrasound contrast agents also provides dynamic quantitative information to develop functional imaging. However, it is mandatory to understand the interaction with the ultrasound beam in order to optimise their use and define the adequate ultrasound sequence.

Artifacts↗
PubMed1999

[Transcranial Doppler and cerebral vasospasm].

Increase in transcranial Doppler ultrasound flow velocities in the major basal arteries correlates with symptomatic vasospasm. Transcranial Doppler examinations are performed using a pulsed Doppler Probe via the trans temporal approach. Transcranial colour-coded real time sonography can be useful and help to identify the cerebral arteries. Maximum flow velocities of > 200 cm/sec are associated with cerebral ischemia and infarction. A maximum rise in Doppler velocity of more than 50 cm/sec/24 h is correlated with poor outcome. Using a diagnostic cutoff of 130 cm/sec a 87% positive predictive value can be obtained using TCD in the middle cerebral artery. Numerous factors affect Doppler flow velocities and may lead to erroneous conclusions about the presence or absence of vasospasm. Flow velocity is directly related to cerebral blood flow. Intracranial pressure, blood pressure and volume, hematocrite and subarachnoid hemorrhage affect Doppler flow velocities. False-negative examinations of vasospasm using TCD are associated with distal vasospasm, severe spasm of the carotid siphon, chronic high blood pressure and increased intracranial pressure.

Blood Flow Velocity↗
PubMed1999

[Brain CT scan for acute cerebral infarction: early signs of ischemia].

Computed tomography (CT) is widely used for early evaluation of acute strokes. Most importantly, CT excludes acute hemorrhage or other diseases mimicking ischemia. Therefore, CT is the main imaging examination in patients with brain ischemia and when antithrombotic agents are being considered. During the first hours after acute ischemic stroke, the CT does not usually show much in the first 24 hours. However, early abnormal findings on CT scan have been described such as the hyperdense middle cerebral artery sign (HMCAS), and reduced contrast attenuation of the cerebral parenchyma. HMCAS reflects arterial occlusion. Early parenchymal abnormalities, the attenuation of lentiform nucleus (ALN), loss of the insular ribbon (LIR) or hemispheric sulcus effacement (HSE) occur less frequently and they are positive criteria for cerebral in progress. Early parenchymal abnormalities might also predict subsequent infarct extension and hemorrhagic transformation. Therapeutic trials of ischemia in MCA territory involved decision making when the CT may not show obvious ischemic changes. Finally, initial CT findings may also help to predict response to therapy.

Acute Disease↗
PubMed1998

[Role of transcranial ultrasonography in neuroradiological diagnosis].

Blood flow within the major arteries supplying the brain can be studied with transcranial Doppler sonography, a noninvasive, portable procedure. We describe the technique of examination, as well as indications in children and adults such as the investigation of intracranial stenosis, collateral pathways, vasospasm, cerebral emboli and arteriovenous malformations.

Adult↗
PubMed1996

MRI and MR angiography of persistent trigeminal artery.

We describe the MRA and MR angiography (MRA) features of persistent trigeminal artery (PTA) found incidentally in eight patients, with special attention to its origin, site and course. The different patterns of posterior communicating arteries were also noted. The PTA were shown on sagittal, coronal and axial MRI and on MRA. In four cases, the PTA arose from the lateral aspect of the intracavernous internal carotid artery, ran caudally, passing round the bottom of the dorsum sellae to join the basilar artery. In the other four cases, it arose from the medial aspect, ran caudally through the sella turcica and pierced the dorsum sellae to join the basilar artery. The posterior communicating arteries were present unilaterally in five cases and bilaterally in one, and absent bilaterally in two. Identification of a PTA with a trans-sellar course is crucial if a trans-sphenoidal surgery is planned.

Adolescent↗
PubMed1996

Early CT signs in acute middle cerebral artery infarction: predictive value for subsequent infarct locations and outcome.

During the first hours after acute ischemic stroke, the CT usually shows no abnormalities. Therapeutic trials of ischemia in the middle cerebral artery (MCA) territory involves decision-making when the CT may not show obvious ischemic changes. We reviewed 100 consecutive patients, admitted within 14 hours after a first stroke. Selective criteria were clinical presentation with MCA ischemia and at least two CTs (1 initial and 1 control). All CTs were retrospectively analyzed by at least two physicians blinded to the patient's status. On the first CT, early signs were hyperdense MCA sign (HMCAS), early parenchymatous signs (attenuation of the lentiform nucleus [ALN], loss of the insular ribbon [LIR], and hemispheric sulcus effacement [HSE]), midline shift, and early infarction. Subsequent infarct locations were classified according to total, partial superficial (superior or inferior), deep, or multiple MCA territories. Clinical features, etiology, and Rankin scale were collected. There were 52 women (mean age 70.8). The CTs were performed at mean 6.4 hours (1 to 14 hours) and before the sixth hour in 62% of the patients. Early CT was abnormal in 94% of the cases, and the abnormalities found were an HMCAS in 22 patients, ALN in 48, LIR in 59, HSE in 69, midline shift in 5, and early infarct in 7. CT was normal in six patients where it was performed earliest (mean 4.5 hours) and in the oldest patients (mean age 80.1). Early parenchymatous CT signs were significantly associated with subsequent MCA infarct location and extension: ALN and deep infarct, HSE and superficial infarct, LIR and large infarct. HMCAS was never found in isolation and was always associated with the three other signs in extended MCA infarct. The presence of two or three signs (ALN, LIR, or HSE) was associated with extended MCA infarct (p < 0.001) and poor outcome (p < 0.001). Our findings suggest that CT frequently discloses parenchymal abnormalities during the first hours of ischemic stroke. Early signs allow the prediction of subsequent infarct locations; CT may provide a simple tool in evaluating the early prognosis of MCA infarction and thus may be useful in selecting better treatments.

Adult↗
PubMed1995

The role of magnetic resonance imaging in the diagnosis of endocrine tumours of the sellar region in children.

Most tumours of the sellar region in children give rise to one or more of the following endocrinological symptoms; anterior pituitary hypersecretion syndromes, growth delay, diencephalic syndrome, diabetes insipidus or precocious puberty. Magnetic resonance imaging enables the visualization of tumours, providing recognizable characteristics allowing the relatively easy recognition of pituitary adenomas, craniopharyngiomas, germinomas, hamartomas, hypothalamic astrocytomas as well as granulomatous proliferations.

Child↗
PubMed1994

Intracranial alveolar echinococcosis: CT and MRI.

Intracranial alveolar echinococcosis is uncommon. We report a patient with right frontal lobe and palpebral lesions secondary to a primary hepatic focus with secondary lesion in the lung. The intracranial and palpebral cystic masses were totally removed and both proved to be alveolar hydatid cysts. An unusual feature in this case is CT and MRI demonstration of dural and bony extension.

Brain Diseases↗
PubMed1993

Pituitary microadenomas: early enhancement with dynamic CT--implications of arterial blood supply and potential importance.

In a search for early contrast medium enhancement, which can indicate the presence of direct arterial supply, a retrospective review of dynamic computed tomographic (CT) scans was performed in 260 patients with a pituitary microadenoma smaller than 10 mm in diameter. Fifty patients underwent examination with dynamic CT for nonendocrinologic disease as a control group to establish the normal pattern of pituitary gland enhancement. One hundred seventy microadenomas (65.4%) displayed the usual dynamic CT pattern (ie, they did not show early enhancement before that of the portal system of the pituitary gland: those pituitary microadenomas appeared less enhanced than the normal pituitary gland during the entire examination). On the other hand, in 90 microadenomas (34.6%), early partial or complete enhancement was seen within the microadenoma before the normal portal enhancement of the gland. Therefore, analysis with dynamic CT yields two groups of pituitary microadenomas separable on the basis of blood supply: those with portal blood supply only and those with partial or predominantly direct arterial blood supply; in theory, the second group avoids hypothalamic control.

Adenoma↗
PubMed1991

Radioanatomy of the laterosellar veins. Value of dynamic computerized tomography.

Dynamic computerized tomography is a simple and rapid technique which can provide an accurate mapping of the vascular elements of the cavernous sinus. It is not very different from the technique used to visualize the capillary bed of the pituitary gland and its progressive contrast enhancement. From a series of 780 dynamic CT explorations, we were able to individualize 5 groups of veins: (1) the veins of the lateral wall of the cavernous sinus; (2) the veins of the infero-lateral group, located beneath the intracavernous segment of the internal carotid artery (ICA); (3) the vein of the carotid sulcus, located between the intracavernous ICA and the carotid sulcus; (4) the medial vein, situated between the intracavernous ICA and the pituitary gland, and (5) the pericarotid plexus. In some cases the anterior and inferior coronary sinuses and the basilar sinus can be visualized.

Capillaries↗
PubMed1990

Free-floating thrombus of the extracranial internal carotid artery.

Free-floating clots of the extracranial internal carotid artery are generally considered as surgical emergencies. This retrospective study analyzes six free-floating clots diagnosed by arteriography. Three of these patients had a fixed stroke while the other three had an evolving stroke. Three patients had antecedent ocular or hemispheric transient ischemic attacks. The causes of free-floating clots in the internal carotid artery were atheromatous stenosis in two cases, ulcerated plaque in three cases, and carotid artery dissection in one. All six patients were seen late, approximately 15 hours after their neurologic accident. They were treated with intravenous heparin over a two to five week period. Repeat arteriograms demonstrated complete clot lysis in four instances, while partial lysis was seen in one case. Moderate extension of thrombus occurred in one case only. No further neurologic complications were noted during the treatment by heparin. As indicated by follow-up arteriographic findings, secondary surgery was performed for major carotid lesions and residual clots in five cases. The free-floating thrombus syndrome of the carotid artery should not be considered as a surgical emergency when discovered late in the wake of an acute neurologic accident.

Carotid Artery Thrombosis↗
PubMed1990

[Intraluminal thrombosis of the cervical internal carotid artery].

Intraluminal clot of the internal cervical carotid artery is commonly thought to require emergency surgery: 7 intraluminal clots specially threatening (6 of whom had a long defect--15 mm and more) are demonstrated by intraarterial digital angiography--4 patients experienced mild stroke, 3 major stroke. 3 of whom had previous recurrent T.I.A. (3 transient blindness, 1 hemispheric TIA). Carotid angiography identified 3 severe atherosclerotic stenosis, 3 ulcerated plaques and 1 dissection. One patient with coma carus died quickly. Anticoagulation therapy (6 cases) was made, 4 weeks along, without neurologic complications. Follow-up angiograms showed total resolution (4 cases), partial lysis (1 case) and mild extension (1 case). Delayed endarterectomy was made only for severe carotid atherosclerosis (5 cases). In our experience, intraluminal clot of the carotid artery may not be a surgical emergency but require anticoagulant therapy and delayed surgery if major underlying lesions.

Carotid Artery Thrombosis↗