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Biomedical subjects

P Germain

Publications and source records attributed to P Germain.

At least 91 records · Page 5Linked to original sources

[Detection of recent myocardial infarction by spin-echo MRI. Value of the third echo].

Seventeen patients underwent MRI spin-echo imaging (Magniscan 5000) 7 to 21 days after acute myocardial infarction (10 anterior, 7 inferior--average 13.1 +/- 3.7 days). The success rate of visualisation of AMI evaluated independently by a qualitative score (from 0 to 4) based on the brilliance of the myocardial signal after taking steps to eliminate the brillance of pericardial fat and subendocardial flow signals, was 3.1 +/- 0.87 in anterior AMI (10 out of 10) and 1.28 +/- 1.25 (4 out of 7) in inferior AMI (p less than 0.007). The diagnostic sensitivity was increased when images of the third echo were used (13 out of 17) compared to those of the second echo (8 out of 17, p less than 0.016). The value of the 3rd echo is explained and emphasised. Abnormal intramyocardial signals were not recorded in a control group of 10 patients under similar conditions of multi-echo imaging. Finally, significant correlations were observed between peak CPK concentrations and the MRI score (r = 0.62; p less than 0.01) and between peak CPK and the number of sections in which the hyperbrilliant signal was observed (r = 0.74; p less than 0.001): this may open the day to quantification of myocardial necrosis by MRI.

Adult↗

[Diagnosis of double aortic arch in the neonatal period. Contribution of magnetic resonance imaging. Apropos of a case].

The authors report a case of double aortic arch in the newborn (age: 1 month) explored with magnetic resonance imaging. MRI offers a non invasive and non ionizing examination very well-tolerated by the patient if a correct methodology is used (total acquisition time 40 mn). The quality of the images is sufficient for diagnosis and presurgical evaluation: the diameter, the permeability and the relationship with the surrounding organs of the respective aortic arches were well demonstrated with this technique. The contributions of MRI with respect to 2-D echocardiography and angiography as well as the future possible totally non invasive evaluation of this cardiac anomaly is discussed.

Aorta, Thoracic↗

[Magnetic resonance imaging in the diagnosis of myxedematous pericardial effusions].

Two cases of myxedematous pericardial effusions studied by magnetic resonance imaging (MRI) are reported. After a reminder of the place of pericardial involvement in this disease, the advantage of MRI which provides original semiologic factors on the analysis of topographic extension and on the approach of the cellular characteristics of the effusion, is presented. Concerning the latter, difficulties of interpretation and current imprecisions are discussed but we will especially remember the advantage of this recent technique in the diagnosis of an effusion, even moderate, in hypothyroidism, mainly in patients with poor sonographic response.

Adult↗

[Value of nuclear magnetic resonance in dilated cardiomyopathy. Approach to intraventricular hemodynamics].

The value of magnetic resonance imaging (MRI) with multiechoes spin-echo sequences was investigated in 22 patients with dilated cardiomyopathy (group I) and 25 normal subjects serving as controls (group II). The results of MRI in group I were compared with those of echocardiography and radionuclide ventriculography. Measurements of left ventricular dimensions at echography and MRI showed a tendency, with MRI, to overestimate wall thickness and underestimate ventricular diameter. Thus, for diastolic LV we had 63.8 +/- 10.5 mm with MRI vs 70.6 +/- 7.6 mm with echography, the corresponding figures for posterior wall thickness being 112 +/- 1.4 mm vs 9.9 +/- 1.1 mm respectively. These differences seem to be due to MRI introducing a partial volume effect dependent on the thickness of slices and of their orientation in relation to the cardiac axis. MRI evaluation of left ventricular function by calculation of myocardial fibre shortening fractions correlated poorly with the echocardiographic value of the same parameter and with the radionuclide ejection fraction (r = 0.58 and 0.575 respectively; p less than 0.05). For better quantification of the cardiac pump function, planimetry of the endocardial contour during diastole and systole is required. It would seem that the value of MRI resides in the possibility it offers to explore left intraventricular haemodynamics by studying the "flow signal" obtainable from multiechoes sequences at different moments of the cardiac cycle. During systole, we found a left intraventricular signal that was reinforced on even echoes and much more intense in cardiomyopathy patients (scores = 1.61 +/- 1.06) than in controls (score = 0.77 +/- 0.7; p less than 0.01). The intensity score for this signal correlated with the ejection fraction in group I subjects (r = 0.82).

Adult↗

[Spatial ventricular gradient studied by computerized vectorcardiography. Normal and pathological values. Interpretation and clinical evaluation].

The ventricular gradient is a reflection of uneven ventricular repolarisation. Until recently is was only appreciated in the frontal plane of the classical electrocardiogramme and expressed as the sum of the vectors representing the surfaces under the QRS complex and T wave. We used computerised vectorcardiography to obtain a more exact evaluation of the size and spatial orientation of the vector gradient. The spatial vector gradient was calculated in a control group and in a number of pathological conditions. The reference values were established in 70 normal subjects with a mean age of 36 +/- 21 years: 0.092 +/- 0.016 m V.s for amplitude: 38.4 degrees +/- 6.1 for thesite and 21.6 degrees +/- 8.7 for the azimuth. The size and spatial orientation of the ventricular gradient can be used to define normal limits and to distinguish subgroups by using the values of the site and azimuth. The spatial ventricular gradient is a new approach to defining the limits of normality in poorly understood abnormalities of ventricular repolarisation. It may also be useful in the comprehension of certain forms of cardiac arrhythmia related to desynchronisation of ventricular repolarisation.

Adolescent↗

[Nuclear magnetic resonance in the diagnosis of aortic diseases].

The diagnostic value of nuclear magnetic resonance imaging was assessed in a number of aortic pathologies: aneurysms of the thoracic and abdominal aorta, sinus of Valsalva aneurysms and dissection of the aorta. The imager was equipped with a resistor magnet providing a field of 0.15 Tesla. An electrocardiographic gating system was perfected. The images obtained were very satisfactory as they provided three dimensional morphological information and a qualitative assessment of blood flow. Further studies are now required with comparison with other invasive and non-invasive diagnostic methods to determine the clinical role of NMR imaging and to evaluate the diagnostic sensitivity and specificity of this new technique.

Aortic Dissection↗

[Nuclear magnetic resonance. Our preliminary experience on the normal heart and in various cardiopathies].

Nuclear magnetic resonance imaging (NMRI) is applied in our department to the study of the normal heart and in aortic, pericardial and myocardial pathologies: aortic aneurysms, hypertrophic cardiomyopathies, myocardial infarction, pericarditis and congenital cardiopathies. The apparatus used consists of a resistive magnet which provides a field of 0.15 Tesla. Synchronisation with the electrocardiogram leads to improvement of the cardiac signals. The documents obtained are promising to the extent that information concerning cardiac structure is provided in three planes (frontal, sagittal and horizontal) and is complementary to that provided by echocardiography, isotopic techniques and contrast angiography. The future potential of the method is considerable, particularly in the area of tissue characterisation.

Aorta↗

[Bioconversion of steroids in mutants of Nocardia restrictus].

Nocardia restrictus grows quickly on synthetic media containing different carbonated substrates (steroids, organic acids). The control of growth parameters of this microbial species allowed the development of the production and selection methodology for mutants unable to grow on androst-4ène-3,17-dione. A stable mutant convert androst-4-ène-3,17-dione in perhydroindan propionic acid without addition of any degradation inhibitor in the medium.

Androstenedione↗