Biomedical subjects

K S Chuang

Publications and source records attributed to K S Chuang.

21 records · Page 2Linked to original sources

PubMedDate not supplied

A fast dual-energy computational method using isotransmission lines and table lookup.

An efficient method has been developed to speed up the computational time required for tissue separation after the dual-energy scan in computerized tomography and digital radiography. This method consists of two steps. First, an isotransmission line method is used to replace the iterative algorithm for solving the two nonlinear equations, which is computationally noisy and sensitive. Second, two tables, one for the aluminum component and the other for the plastic component, are derived from calibration data in order to replace calculation by a table lookup. Results from this method are compared with the conventional method.

Models, Structural↗

PubMedDate not supplied

Evaluation of inherent gray-level dynamic range in a digital image using the runs test and join-count statistics.

The dynamic range of the gray level of a digital image is limited by the noise it contains. Two statistical methods called "runs test" and "join-count statistic" are used to measure the noise level in a digital image. A residual image is formed by subtracting an original image from its smoothed version. Theoretically, the noise level in the residual image should be identical to that in the original image. The noise level is determined by examining each bit plane of the residual image individually starting from the least significant bit up to the bit plane whose statistic does not show a random pattern. Images from three digital modalities: computerized tomography, magnetic resonance, and computed radiography are used to evaluate the gray-level dynamic range. Both methods are easy to implement and fast to perform.

Biometry↗

PubMedDate not supplied

Effects of stellate ganglionectomy on the cat cardiovascular function.

The effects of stellate ganglionectomy on cardiovascular function were assessed in pentobarbital-anesthetized cats. A right stellectomy produced much more profound bradycardiac effects than a left stellectomy. This finding demonstrated that the stellate ganglion exerted a lateralized influence on heart beat in the cat. The cardiovascular response of intact cats to phase 4 (overshoot) of the Valsalva-like maneuver (VM) was reflex bradycardia. In response to VM, however, reflex bradycardia was completely abolished by a right or bilateral stellectomy, or by pretreatment with propranolol, but not by a left stellectomy alone or with phentolamine. The data indicated that the right stellate ganglion in cats makes a major contribution to cardiovascular control, especially over reflex bradycardia mechanisms.

Animals↗