Biomedical subjects
Publications and source records attributed to E Mousseaux.
The authors report a case of severe constrictive pericarditis occurring 6 weeks after coronary bypass surgery and in the absence of any other predisposing factor. The diagnosis was confirmed by CT scan and cardiac catheterisation which showed signs of a diastole. The patient died despite early surgical reoperation because of the severity of the pericardial fibrosis.
Recent cardiovascular morphologic studies focus on direct innovative ultrafast CT applications in detecting coronary calcifications and assessing pericardial diseases. In functional studies, quantitation of regional and global indicators of myocardial function and structure, such as wall thickness or thickening, volume, and mass, can be performed using ultrafast CT and MR imaging with similar approaches. Recent ultrafast CT developments illustrate the fact that cardiac tomographic imaging is evolving rapidly. The production of three-dimensional images from tomography, which is still uncommon, has enhanced resolution and wall motion analysis. Applications will have a major impact on the knowledge of cardiac physiology and the understanding of cardiovascular diseases, if not in daily patient care. Further developments in computer-automated analysis from cardiac ultrafast CT or MR images must be carried out to gain clinical acceptance and to facilitate the routine and consistent measurements of the parameters of cardiac function.
Ultrafast computed tomography and magnetic resonance imaging are two new methods of cardiac imaging. Measurements of left ventricular volume (end-diastolic, end-systolic volume, stroke volume) and mass have been validated with both methods. The calculations are independent of the geometric shape of the ventricle. Although regional analysis is difficult because of the complex movement of the left ventricle in the tomographic cuts, these methods present a number of advantages: excellent temporospatial tomographic resolution, approximately the same in all dimensions, appreciation of endocardial movement from an epicardial centre, the potential to record their transform spatial data in 3 dimensions from initial planar acquisition. However, all potential regional measurements are still being validated as they are operator-dependent and require visual identification and manual tracing of the cardiac contours or local infrastructures which affect the results of these techniques which are still relatively little used in cardiac imaging. In the context of clinical evaluation, these relatively non-invasive methods will become extremely accurate in the appreciation of parameters of left ventricular geometry and function. They will become very useful in the determination of the myocardial effects of drugs, surgery or other interventional procedures in different models of cardiac disease.
Benign non myxomatous cardiac tumors are rare. Between 1968 and 1988, 9 patients presenting benign non myxomatous cardiac tumors were operated in our institution. Tumors were: 2 rhabdomyomas, 2 lipomas, 2 fibromas, 1 pheochromocytomas, 1 mesothelioma and 1 papillary fibroelastoma. Total excision was possible in all cases but one (multiple fibromas). We hereby present a review of the literature on the subject. We focalize on the new imagery techniques in order to help the diagnosis and on the new surgical possibilities (cardiomyoplasty) which make possible complete surgical excision.
The diagnosis of pheochromocytoma is biological. If ultrasound enables the visualization of certain adrenal tumours or hepatic metastasis, in fact two tests enable the topographic diagnosis, the screening of ectopic localizations and metastasis. They are IMBG scintigraphy and tomographic scanning. The place of magnetic resonance imaging is not yet specified. However, it has many advantages: absence of irradiations, good anatomic precision, meticulous screening of ectopic forms, of metastases and of adenopathies, study of the tissue characterization, good definition of the tumour relation with the vascular pedicles and the neighbouring structures.
Two patients who underwent left internal mammary artery (IMA) anastomoses to the left anterior descending artery (LAD) developed sudden angina associated with anterior ischemic changes on EKG in the early postoperative period, one at 4 hr and the other at 3 days following operation. Digitalized arteriography via retrograde injection of the left brachial artery revealed the IMAs, which were partially obstructed because of looping and Kinking, although the anastomoses to the LAD were patent. Reoperation was successful in relieving obstruction by reducing these abnormalities and resulted in an uncomplicated postoperative course following the second operation. Discussion of the etiology, radiological technique of diagnosis, correction, and prevention of this cause of internal mammary graft failure is presented.
Magnetic resonance imaging maps of velocity were acquired with a 1.5-T system in 10 subjects in a plane perpendicular to the main pulmonary artery. Velocity images were successively acquired with a method developed from Fourier-encoding velocity imaging (FEVI) principles with eight gradient steps and one excitation, and with two-point phase-subtraction mapping. Reconstruction in FEVI was implemented by zero-filling interpolation around the eight gradient steps and then around the four central steps. The methods were compared by using estimates of noise in velocity measurements based on the difference between the experimental map and a smooth fitted map. For the same acquisition time, FEVI with four encoding steps was more precise in velocity measurements than phase mapping. Precision was further increased by the use of eight encoding steps, but acquisition time was doubled.
Detection of myocardial borders on sequences of electron beam CT images is carried out using an adaptive segmentation algorithm developed to enhance dynamic analysis of cardiac function. Adaptivity is based on description of the myocardial borders from the mean and standard deviation of the grey level and gradient distributions on each image of the sequence. Comparison of segmentations from five experimentators with automatically determined borders on a set of 416 endocardial and epicardial contours indicated differences between automatic and manual tracing very close to differences due to inter-observer reproducibility.
To explore the potential role of MRI in detecting cardiac allograft rejection in transplant recipients using gadolinium tetraazacyclododecane tetraacetic acid (Gd-DOTA) for contrast enhancement, we examined 7 normal healthy volunteers and 39 patients separated into three groups according to histological findings. Quantitative myocardial enhancement (ME), expressed as the ratio of maximum signal intensity after intravenous Gd-DOTA injection to signal intensity before intravenous injection of Gd-DOTA, was significantly lower for patients without histological rejection (n = 14; regional ME = 83 +/- 41%; mean ME = 53 +/- 24%) when compared with patients with grade 1 histological rejection (n = 18; regional ME = 122 +/- 20%, p = 0.02; mean ME = 70 +/- 14%, p < 0.05) and with patients with grade 2 or 3 rejection (n = 7; regional ME = 135 +/- 44%, p = 0.02; mean ME = 81 +/- 27%, p < 0.05). Myocardial enhancement was not significantly different in patients with grade 1 histological rejection compared with patients with grade 2 or 3 rejection. Because predominant focal areas of ME were observed in all patients, regional ME seemed a better measurement than mean ME to distinguish focal histological changes when the rejection process is beginning. More sophisticated software analysis is necessary to quantify and map high ME to establish the exact relationship between the extent of edema and the severity of rejection.
PURPOSE: The purpose of this work was to assess typical findings of Takayasu arteritis on serial CT examinations following therapy. METHOD: Serial CT studies were performed on 16 patients with early phase Takayasu arteritis. Mural or luminal changes of the aorta on successive CT scans were compared with clinical data. RESULTS: Vascular lesions progressed during follow-up in 6 of 16 patients. In one patient, progression of lesions was symptomatic. In the other five of six patients with worsening lesions, vascular progression occurred without new clinical symptoms and was first identified on CT scans. One of these five had dilatation of the ascending aorta and required aortic repair. Four others had progression of stenotic vascular lesions leading to changes in medical treatment only or in combination with either surgery or angioplasty. For two of them, CT examinations showed decreased mural lesions after changes in medical treatment. CONCLUSION: CT examinations performed in treated patients with Takayasu arteritis demonstrate either regression, stabilization, or progression of vascular lesions. Serial CT examinations may thus be useful for evaluating response to treatment.
Post-operative deformation of the aortic arch architecture is associated with an increased risk of hypertension following correction of coarctation. In addition to morphological analysis, MRI allows a functional analysis of the thoracic aorta. We report three examples which illustrate the direct relationship between aortic arch morphology and blood flow in the thoracic aorta.
The mechanisms of secondary hypertension after repair of coarctation of the aorta are not well understood. Abnormalities of the architecture of the aortic arch and their consequences on blood pressure have not been studied. In order to study the relationship between abnormalities or aortic arch architecture and resting blood pressure ninety-four patients without re-coarctation were followed up prospectively from 1997 to 2004 (mean age 16.9 +/- 8.1 years; mean weight 57.5 +/- 18.3 Kg; interval since surgery 16.3 +/- 5.4 years). All underwent MRI angiography of the thoracic aorta which enabled the abnormalities to be classified in 3 groups: gothic arch, crenellated arch and roman arch. Twenty-four patients (25.5%) were hypertensive and 70 (74.4%) normotensive. There were 40 gothic arches (42.5%). 14 crenellated arches (15%) and 40 roman arches (42.5%). Gothic arches were more commonly observed in the hypertensive patients (18/40, [45%, 95% CI 31-62]) than the crenellated arches (4/14, [28.5%, 95% CI 7-48]) or the roman arches (2/40, [5%, 95% CI 2-12]). Only the gothic arch was independently correlated with hypertension on multivariate analysis. The authors conclude that gothic deformation of the aortic arch is an independent predictive factor of hypertension in patients operated for coarctation with an excellent result on the isthmic region. Patients with a gothic appearance of their aortic arch should be followed up closely.
A case of histologically confirmed benign lipoma of the right atrium is presented. Magnetic resonance imaging was successfully used to visualize and characterize the tumor previously detected by echocardiography. T1-weighted MR was superior to echocardiography and was in surgical agreement with examination in identifying the relationship of the lipoma to the right atrial wall, the coronary sinus, and the interatrial septum. Comparison of measurements of the tumor's signal intensities on T1- and T2-weighted images and T2 relaxation time with those of surrounding myocardium and mediastinal fat allowed a preoperative diagnosis of lipoma. Magnetic resonance may obviate surgical intervention in selected asymptomatic cases where the diagnosis of benign lipoma appears likely.