Ultrasonic computed tomography of the breast. Improvement of image quality by use of cross-correlation time-of-flight and phase-insensitive attenuation measurements.

The authors present two methods of reducing refraction artifacts in ultrasonic computed tomography of the breast. Measuring the time of flight of sonic pulses by cross-correlation instead of leading-edge detection significantly reduces distortion and improves resolution in speed-of-sound images. Phase-insensitive reception of pulse energy across a large aperture array is shown to be superior to a conventional single-element transducer for attenuation imaging.

Estimation of ultrasonic attenuation and mean backscatterer size via digital signal processing.

The backscattered rf signals from the lungs of fetal sheep during their last trimester of development were digitized and processed in an attempt to correlate ultrasonic parameters with measured functional parameters related to lung maturation. The broadband, post- TGC , rf signal of a commercial B-mode ultrasonic scanner was digitized at a sampling rate of 25 MHz. Sorting excluded data from regions of rib shadowing and other nonlung structures from analysis.

Hepatic imaging: positron emission tomography, digital angiography, and nuclear magnetic resonance imaging.

Major advances in diagnostic imaging of the human body have been made in recent years. Positron emission tomography, a technique founded on advances in radiopharmaceuticals and radionuclide imaging apparatus, permits imaging regional metabolism, metabolite distribution, and flow. Thus far, its major applications have been in the study of the brain, and to a lesser extent, the heart; however, it is also finding a role in the study of the liver.

A tissue-equivalent upper abdominal phantom.

The first prototypes of an abdominal phantom have been constructed. The phantom is intended for eventual use in training diagnostic ultrasound personnel and in demonstrating commercial equipment. It is constructed from plastics believed to be stable and approximately tissue-equivalent at room temperature.

Platelet size in myocardial infarction.

The mean platelet volume and platelet count were measured serially in 100 patients soon after myocardial infarction and again at a follow up clinic about seven weeks later. The results were compared with those in age matched controls. The mean platelet volume after infarction (mean 9.

Postoperative wound infections: a study of bacteriology and pathogenesis.

Of 200 patients, 6.5% were skin carriers of Staphylococcus aureus and 3.5% became skin carriers after admission.

Sonographic identification of lung maturation in the fetal lamb.

Ultrasound evaluation of fetal lung development in utero could be a noninvasive method for frequent monitoring of the state of pulmonary maturity and predicting when parturition could occur with minimum or no risk of respiratory distress syndrome of the newborn. In cases of high-risk obstetric management in premature labor, this ability may be a particularly useful tool. To pursue this possibility, the lungs and livers of 13 living fetal lambs were successfully imaged with a modified clinical B-scanner under carefully controlled conditions; physiologic function tests on the excised lungs determined the state of pulmonary maturity.

Exercise after myocardial infarction: a controlled trial.

Six weeks after acute myocardial infarction, 303 men were randomly divided into exercise and control groups. The exercise group attended the hospital gymnasium twice weekly for a three-month supervised exercise course. Both groups were exercise tested before and after the course and at subsequent follow-up.

Epidemic of hospital-acquired infection due to methicillin-resistant Staphylococcus aureus in major Victorian hospitals.

During 1979, the Victorian Health Commission received reports of a rising proportion of methicillin-resistant Staphylococcus aureus (MRSA) isolates from an increasing number of institutions. At least 31 metropolitan hospitals were involved, and six of these reported MRSA totaling between 20% and 40% of all Staph. aureus isolates.

Anthropomorphic breast phantoms for assessing ultrasonic imaging system performance and for training ultrasonographers: part II.

Three prototype anthropomorphic breast phantoms are discussed. The phantoms were constructed using ultrasonically tissue-mimicking materials; these materials mimic various tissue parenchymae in terms of attenuation, speed of sound, density, and scatter level. Realistic artifacts related to refraction and reflection at interfaces between different simulated parenchymae are produced.

Anthropomorphic breast phantoms for assessing ultrasonic imaging system performance and for training ultrasonographers: part I.

Three prototype anthropomorphic breast phantoms are discussed. The phantoms were constructed using ultrasonically tissue-mimicking materials; these materials mimic various tissue parenchymae in terms of attenuation, speed of sound, density, and scatter level. Realistic artifacts related to refraction and reflection at interfaces between different simulated parenchymae are produced.

Breast imaging in coronal planes with simultaneous pulse echo and transmission ultrasound.

Clear delineation of breast architecture was achieved with compound pulse echo ultrasound imaging in which the images were acquired in the coronal planes used for quantitative transmission ultrasonic computed tomography. Since most connective tissue planes in the breast radiate toward the nipple, compound scans from the sides of the breast record normal interfaces more consistently and reveal greater symmetries in normal portions of relatively full breasts than do conventional scans in sagittal or transverse planes. Simultaneous acquisition of the pulse echo images and images representing the local ultrasound attenuation coefficient and speed of ultrasound suggested complementary role for reflection and through-transmission images in breast cancer detection.

Toxicology of the 8-aminoquinolines and genetic factors associated with their toxicity in man.

In vitro studies on primaquine have been carried out to examine its ability to stimulate the oxidative pathway of glucose metabolism in human erythrocytes and in vivo studies were carried out after ingestion of the drug to determine plasma levels and to investigate the formation of metabolites and the effects of the drug on human erythrocytes. These investigations showed that:1) Two mechanisms are involved in the stimulation of the oxidative pathway. This was demonstrated by comparing the effects of methylene blue, ascorbic acid, primaquine, and other drugs on normal, glutathione-reductase-deficient, and G6PD-deficient erythrocytes.