ABSTRACT
A new optical probing method with increased interferometric sensitivity for a low-density gas jet characterization is presented. The proposed technique employs a Michelson interferometer with a self-imaging object arm, which enables the relay imaging of the object on itself, and in this way, the phase sensitivity of the device is increased by a double propagation of the object laser beam through the gas jet. The wavelength of 405 nm was chosen to further increase the sensitivity by increasing the probe wavenumber. A low-density argon gas jet with various backing pressures was characterized by our method and by a commonly used Mach-Zehnder interferometer setup showing the expected twofold increase in the signal to noise ratio in the double pass configuration.
Subject(s)
Diabetes Mellitus, Type 2/pathology , Diabetic Angiopathies/pathology , Female , Humans , Male , Middle Aged , Time FactorsSubject(s)
Coronary Vasospasm/diagnosis , Electrocardiography , Exercise Test , Angina Pectoris, Variant/physiopathology , Female , Humans , MaleABSTRACT
The authors analysed in a group of 82 patients with a symmetric left ventricle and a homogeneous ventricular wall thickness the reliability of M-mode echocardiography in recognizing left ventricular hypertrophy. In concentric hypertrophies, a sufficient diagnostic criterion is ventricular wall thickness. Measurement of the interventricular septum offers a better correlation with angiographic values (r = 0.609, p less than 0.001) than measurement of the posterior wall (r = 0.358, p less than 0.01); a correct diagnosis can be determined in 84%. In excentric hypertrophies, the hypertrophy must be assessed on the basis of calculating the left ventricular mass. The most accurate of echocardiographic methods proved to be the calculation according to the authors' own formula (r = 0.760, p less than 0.001), which recognizes left ventricular hypertrophy correctly in 85%. The diagnostic correctness of Teichholz' formula is 80% and of the cubic formula 74%. Fortuin's equations proved to be of no value for documenting ventricular hypertrophy. In a group of 13 patients with hypertrophic cardiomyopathy, the correlation between angiographic and echocardiographic values of the left ventricular mass was very low (r = 0.534, p = 0.05).
Subject(s)
Angiography/standards , Cardiomegaly/diagnosis , Echocardiography/standards , Cardiomegaly/diagnostic imaging , Cardiomegaly/pathology , Echocardiography/methods , Heart Ventricles , Humans , Myocardium/pathologyABSTRACT
The authors studied at repeated ventriculographic examinations the changes in the left ventricular function after application of routinely used ionic contrast medium and of newer nonionic medium. They demonstrated that ionic medium does not significantly change the left ventricular volume and ejection fraction, but influences the left ventricular diastolic function. Nonionic contrast material does not significantly change the left ventricular function. The mechanism of side-effects of contrast agents and possible indications for the application of nonionic contrast media are discussed.
