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Biomedical subjects

E Mousseaux

Publications and source records attributed to E Mousseaux.

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

Multidimensional MR mapping of multiple components of velocity and acceleration by fourier phase encoding with a small number of encoding steps.

Previous studies have shown that the multi-step approach of velocity or acceleration encoding is highly efficient in terms of the signal-to-noise ratio per unit time. This work describes a multidimensional extension of this method for simultaneously measuring multiple components of velocity and acceleration with a few encoding steps. N flow dimensions were encoded with an ND-matrix, obtained by combining the various flow-encoding gradients. The small matrix obtained with as few as two encoding steps can be extended by zero-filling in all N dimensions and using ND-Fourier transformation to obtain the maximum of the resulting peak in the ND-matrix, which gives simultaneously all the components of velocity and/or acceleration. The processing time was shortened by using a method of phase computation that gives the same precision as Fourier transformation, but is much faster. A rotating disk was used to show that the velocity-to-noise ratio increases with the number of dimensions acquired, demonstrating the efficiency of multidimensional flow measurements. The feasibility of the method is illustrated by 3D maps of the myocardium velocity, and 2D measurement of velocity and acceleration in the ascending aorta-both obtained by multidimensional phase encoding in volunteers.

Acceleration↗
PubMed2000

Infectious pseudoaneurysms suspected at echocardiography: electron-beam CT findings.

PURPOSE: To review the electron-beam computed tomographic (CT) findings in patients with clinical endocarditis and suspected of having perivalvular pseudoaneurysms at echocardiography and to compare these findings with echocardiographic data. MATERIALS AND METHODS: Data on 17 patients who underwent electron-beam CT for suspicion of perivalvular infectious pseudoaneurysm at echocardiography were retrospectively reviewed. Thirteen patients had a history of valvular surgery. Electron-beam CT findings-lesion size, number, extent, and relationships with surrounding structures, and associated lesions-were compared with echocardiographic and surgical and/or autopsy data. RESULTS: In all patients, electron-beam CT depicted one or more abnormal cavities that filled with contrast material after bolus injection. The mean size (3.5 cm) and number (n = 21) of pseudoaneurysms recorded with electron-beam CT were greater than those recorded with echocardiography (2.9 cm and n = 13, respectively). Associated electron-beam CT findings included valvular vegetations in three patients; mediastinitis in two; and coronary arterial involvement in six. In eight (47%) patients, electron-beam CT depicted a pseudoaneurysm or an additional pseudoaneurysm that was only suspected-not depicted-at echocardiography. Transthoracic and transesophageal echocardiography resulted in underestimation of lesion number, size, and extent and associated lesions, particularly in patients with valvular prostheses or voluminous lesions. CONCLUSION: Thoracic infectious pseudoaneurysms are well depicted with electron-beam CT, which may be a useful addition to echocardiography for detection of this disease and thus help in preoperative planning.

Adult↗
PubMed2000

[Diagnosis of cardiac tumor by percutaneous thromboaspiration. A case report].

Percutaneous endovascular thromboaspiration is a valuable tool as illustrated by the case of a patient suffering from a large intracardiac tumour. Histological and immuno-histochemical analysis of the tumour fragments provided the diagnosis of a cardiac angiosarcoma. The patient was a 44 year old man admitted for a large sero-sanguinous pericardial effusion which recurred after drainage. The case was complicated by a haemorrhagic cerebrovascular accident unrelated to a secondary deposit. Initially suspected after transthoracic echocardiography, the diagnosis of a tumour invading the right atrium was confirmed by transoesophageal echocardiography and cardiac CT scan. Surgery was declined and as the diagnosis of lymphoma could not be excluded, the patient underwent biopsy by an original method of percutaneous thromboaspiration. This minimally invasive, low cost technique would appear to be a valuable alternative to other endovascular biopsy techniques (saber, biotome) and to surgical biopsy, and could be proposed as the technique of first intent in an a priori non-operable intra-cardiac tumour or when lymphoma is suspected.

Adult↗
PubMed2000

[Left ventricular thrombus revealed by electron bean computed tomography, in a patient with antiphospholipid syndrome].

The authors report a case of a 48 year old woman admitted to hospital because of digital ischemia, in a context of antiphospholipid syndrome. The electrocardiogram-triggered electron beam computed tomography revealed an apical thrombus associated with a thinning left ventricular wall, suggesting painless myocardial infarction. The diagnosis was secondary confirmed by coronarography.

Antiphospholipid Syndrome↗
PubMed1999

Spatial regularization of flow patterns in magnetic resonance velocity mapping.

A technique dedicated to spatial regularization of magnetic resonance (MR) velocity data has been implemented to improve flow image quality. It is assumed that neighboring flow-velocity pixels are partially correlated, although large-velocity discontinuities remain possible. Increasing MR signal magnitude due to the in-flow effect also is used to enhance further reliability of the estimated velocity. By using an eight-step Fourier-encoding approach, 162 "reference" velocity images acquired in the ascending aorta from six healthy volunteers were compared with "raw" and "regularized" images that were computed from only two gradient steps. The mean square error decreased from 0.12 m(2) x s(-2) to 0.06 m(2) x s(-2) (P < 10-9) for velocity pixel values and from 1929 ml(2) x s(-2) to 1336 ml(2) x s(-2) (P < 0.01) for instantaneous flow rates. The regularization of two-step data sets provides the same velocity image quality as that found after using three-step data sets without regularization. The method can be applied to phase-velocity data sets of any MR technique to reduce velocity noise. J. Magn. Reson. Imaging 1999;10:851-860.

Adult↗
PubMed1999

Idiopathic dilatation of the pulmonary artery: report of four cases.

Idiopathic dilatation of the pulmonary artery (IDPA) is a rare congenital disease which is usually detected fortuitously on chest x-ray, thus radiologists must be aware of this clinical entity. This report describes four cases to which Magnetic Resonance Imaging (MRI) played a major role in diagnosing IDPA and in detecting the concomitant findings observed in this disease. MRI is a non-invasive procedure with many advantages for the accurate and reproducible measurement of artery structures, which makes it the preferred option for combined use with echocardiography in the diagnosis and follow-up of patients with IDPA.

Adolescent↗
PubMed1999

Pulmonary arterial resistance: noninvasive measurement with indexes of pulmonary flow estimated at velocity-encoded MR imaging--preliminary experience.

Cardiac output and pulmonary vascular resistance (PVR) were measured in 19 patients by means of catheterization of the right side of the heart. Results were compared with the cardiac output and indexes of pulmonary arterial blood flow estimated with velocity-encoded magnetic resonance (MR) imaging. Correlations were good between estimates with right-sided heart catheterization and those with velocity-encoded MR imaging. By providing accurate pulmonary arterial blood flow measurements, velocity-encoded MR imaging allowed distinction of patients with high PVR from subjects with normal PVR.

Adult↗
PubMed1999

[Spontaneous regression of a false aneurysm of the ascending aorta following surgery for dissection].

We report the case of a 50-year-old man admitted to hospital for a type A aortic dissection. After conventional surgical repair, he was asymptomatic and underwent computed tomography imaging at 15 days, 3 and 6 months. The first CT scan showed a small perigraft circulating false aneurysm which totally disappeared on the last exam. This case emphasizes the potential role of CT scan in the follow-up of patient after aortic surgery and the likely favorable outcome of some false aneurysm.

Aortic Dissection↗
PubMed1999

[Behcet's disease and iatrogenic arterial complications: importance of pre-operative noninvasive explorations].

We report a case of Behçet's disease complicated with a popliteal aneurysm, which appeared 8 years after first etiologic diagnosis. The points of interest of this observation are the pre-operative explorations and particularly the Magnetic Resonance Angiography (RMA). This last seems to be particularly safe for aortic and lower limbs aneurysms explorations, and can be performed without arterial functions. In fact the risk of arteriogram is effective in Behçet's disease with secondary false aneurysms. RMA and US-Doppler scan must be first proposed in Behçet's disease in case of aortic and peripheral aneurysms.

Aneurysm↗
PubMed1999

[Pericardial and myocardial adiastole in rheumatoid polyarthritis].

The authors describe a case of clinical, echocardiographic and haemodynamic adiastole in a man with severe rheumatoid arthritis with a previous history of pericardial effusion. The adiastole was mixed, fibrous pericarditis, confirmed by ultra fast CT scan and at surgery; myocardial adiastole was suspected on finding thickening of the ventricular walls (in the absence of hypertension and coronary artery disease) and, unfortunately, confirmed by the persistence of adiastole despite very satisfactory pericardectomy. The authors underline the involvement of the three cardiac tunics in rheumatoid arthritis and the value of different diagnostic methods in the differentiation between constrictive pericarditis and restrictive cardiomyopathy.

Arrhythmias, Cardiac↗
PubMed1998

A recurrent left atrium leiomyosarcoma.

Cardiac leiomyosarcoma is a rare tumour which can grow either intramurally or extramurally. Its prognosis is dismal. Surgery lengthens survival, but recurrences usually occur in the short term. Gated MRI is useful for the assessment of cardiac masses since it provides fine spatial and contrast resolution. We present the case of a left atrial leiomyosarcoma whose recurrence was diagnosed by gated MRI. Our patient underwent a second resection but died soon after.

Echocardiography, Transesophageal↗
PubMed1998

Cardiac metastatic melanoma investigated by magnetic resonance imaging.

There is a high rate of cardiac involvement in malignant melanoma (MM), but such cardiac metastases are usually diagnosed late. This report describes four cases with different clinical presentations of MM cardiac involvement that were investigated by magnetic resonance imaging (MRI). The MM cardiac involvement was asymptomatic in one case, detected because of a superior vena cava syndrome in a second, and because a tamponade in the remaining two cases. MRI permitted the diagnosis of cardiac metastases of MM, which was not made by echocardiography in one case. By precisely detecting the extent of the tumors, MRI was a great help in management, especially when an isolated cardiac metastasis was suitable for surgical ablation (two cases). Because both clinical signs and transthoracic echocardiogram are not very sensitive for diagnosing MM myocardial involvement, MRI can help provide such a diagnosis and ensure better treatment-monitored decisions.

Aged↗
PubMed1998

[Comparison of magnetic resonance angiography with injection of gadolinium and conventional arteriography of the ilio-femoral arteries].

Twenty-three patients underwent conventional arteriography and 3D contrast enhanced magnetic resonance angiography explorations. The study was limited to the iliofemoral arteries (13 segments for each patient). Each segment was classified as having 0-49%, 50-99% or 100% stenosis. Overall results were excellent with K = 0.822, sensitivity 92% and specificity 93%. Segment by segment analysis corroborated the overall results except for the internal iliac arteries and the deep femoral arteries, demonstrating the limitations of this technique in this series.

Aged↗
PubMed1997

Acceleration mapping by Fourier acceleration-encoding: in vitro study and initial results in the great thoracic vessels.

Acceleration mapping can be conducted by replacing the bipolar gradient pulse of a velocity mapping sequence by a tripolar pulse. However, since the acceleration encoding pulse is longer, the image quality is altered by the requirement of a long echo time. Since Fourier encoding velocity imaging has been shown to be robust, this velocity mapping method was transformed into an acceleration mapping method. Four steps of the tripolar acceleration encoding gradient pulse were applied successively; acceleration was then obtained by Fourier transform after zero-filling. The accuracy of the method was assessed with a phantom giving a pulsatile flow. Acceleration maps of the ascending aorta and pulmonary artery were obtained in 10 healthy volunteers. The acceleration values measured were in the range of known physiologic values. The feasibility of Fourier encoding acceleration imaging was also demonstrated in four patients.

Adolescent↗
PubMed1996

Angiographic and electron-beam computed tomography studies of retrograde cardioplegia via the coronary sinus.

Retroperfusion of the coronary sinus does not provide homogeneous distribution of cardioplegic solution. The goal of this study was to analyze the distribution of flow during retrograde cardioplegic infusion in cadaveric human hearts with two different techniques of coronary sinus cannulation: (1) internal occlusion of the coronary sinus by balloon inflation and (2) external occlusion by tightening the orifice of the coronary sinus around a simple catheter. To evaluate differences between the two techniques, angiographic and electron-beam computed tomographic studies were performed. Computed digital angiography was performed on 14 hearts. Angiographic patterns varied according to type of coronary sinus cannulation. With the balloon inflation technique, the marginal vein and the anterior descending vein were perfused first; the posterior descending vein was not perfused. This vein was opacified secondarily through a venovenous anastomosis located at the apex of the heart. Backward flow into the right atrium (steal phenomenon) was demonstrated. At completion of retroperfusion, the inferior part of the septum remained poorly opacified. Conversely, angiographic findings after external occlusion of the coronary sinus revealed simultaneous injection of all venous channels. The entire septum was well opacified at completion of retroperfusion. Electron-beam computed tomographic study was performed on eight hearts with the external occlusion technique and nine with the internal occlusion technique. The computed tomographic findings confirmed the results of digital angiography. The peak myocardial enhancement and the peak rising rate of myocardial enhancement within the interventricular septum were significantly more important (p < 0.0001) when the external coronary sinus occlusion mode was used than when the internal coronary sinus occlusion mode was used. In all hearts except one, the right ventricular wall was not opacified, regardless of the type of cannulation and the type of radiologic analysis. This study demonstrates the importance of coronary sinus cannulation technique in optimizing the protection of the interventricular septum with retrograde cardioplegic infusion.

Adult↗
PubMed1996

Percutaneous treatment of acute iliac artery injury after intraaortic balloon counterpulsation.

We report on a novel approach to correcting iliac artery occlusions caused by aortic counterpulsation. Two patients who had leg ischemia after retrieval of an intraaortic balloon pump underwent angiograms that showed occlusion of the right external iliac artery because of dissection (one case) or thrombosis (one case). Percutaneous self-expandable stents were implanted in the occluded vessels, and they fully restored normal iliac patency with no complications and satisfactory midterm follow-up results. We conclude that iliac artery occlusion induced by aortic counterpulsation can be safely treated by implanting self-expandable stents in cases of acute iatrogenic dissection.

Acute Disease↗