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Usefulness of chest perfusion computed tomography in the diagnosis of diabetic pulmonary microangiopathy

Kalicka R., Browarczyk M., Lipiński S.

Biocybernetics and Biomedical Engineering

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2015

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Vol. 35, no. 1

68--73

EN

This paper presents the usefulness of perfusion computed tomography (pCT) in the diagnosis of diabetic pulmonary microangiopathy. Our previous works have shown that perfusion parameters are useful in the diagnosis of diabetic pulmonary microangiopathy. We are looking for such measurements and perfusion parameters that provide the most accurate diagnosis. Two types of comparison were made based on the results of clinical trials: non-diabetic vs. diabetic and diabetes without microangiopathy vs. diabetes with microangiopathy. Our studies have shown that PS (permeability surface) is only perfusion parameter statistically significant. In certain regions of interest logistic regression as a classifier produces very good results in diagnosing lung microangiopathy: sensitivity Sens = 89% and excellent specificity Spec = 100%. The results were obtained on the base of measurements taken from 23 subjects. These results were compared with results reported in the literature and based on diffusion capacity and spirometry measurements and modeling. None of the previous results was as good as those obtained using the PS and logistic regression for binary classification.

2

The new hybrid pneumo-electrical piston model of lungs mechanics - preliminary tests

Kozarski M., Zieliński K., Pałko K. J., Stankiewicz B., Bożewicz D., Darowski M.

Biocybernetics and Biomedical Engineering

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2009

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Vol. 29, no. 3

3-18

EN

A design principle, construction and results of preliminary tests of a new hybrid physical-electrical model of lungs mechanics has been presented, The methods leading to development of lungs models of different complexity have been also included. The basic component of the model is a voltage controlled Bow source build up with a piston ~ cylinder system driven by a servomotor. This is used to develop a functional module playing a role of an impedance converter transforming an input electrical impedance Z0 of any electrical network connected to its electrical terminals into a pneumatic impedance Zin. Static and dynamic characteristics of the model connected to different pneumatic signal sources have been presented i.e. for the model connected with the respirator (expiration by the respiratory valve) and for the model with free unobstructed expiration. The very good dynamic features (time constant of the piston Bow source less than 1 ms) and a small resultant error of impedance conversion (less than 1%) enable the model to be applied in many application especially when new methods of lung ventilation are developed.

3

A hybrid model of the respiratory system

Michnikowski M., Glapiński J., Guć M., Gólczewski T., Darowski M.

Biocybernetics and Biomedical Engineering

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2009

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Vol. 29, no. 1

71-80

EN

The aim of this work is building a hybrid model of the human respiratory system which enables connecting the real clinical devices (respirators) with the computerized virtual lungs. A simulation of the artificial ventilation of lungs, with the use of the hybrid model and the Siemens Servo 900 respirator, was made. Waveforms of pressure inside the lungs, flow in the respiratory tract, and the lung volume during the simulated artificial ventilation were recorded. The compliance and resistance of the hybrid model of the respiratory system were calculated on the basis of the inspiratory pause algorithms and compared to the values set in the model. The initial tests have shown that the calculated values of the parameters differ by 20% (worst result) from the values set in the model. The model will enable the investigation of the different modes of lung ventilation, as well as educational presentation of the respirator-patient interaction.

4

Stimulation of nerves innervating the pancreas of a dog

Rozman J., Trlep M., Zorko B., Bunc M.

Journal of Technical Physics

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2002

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Vol. 43, no 4

467-473

EN

The purpose of the study was to evaluate the influence of electrical stimulation of nerves innervating the pancreas on the function of the cardiovascular system, lungs and urinary tract, measured as an ECG, blood pressure and pressure in the bladder of a dog. Spiral cuffs with 33 electrodes (1.0 x 2.0 mm) within a silicone sheet were manufactured and implanted in a Beagle dog in the vagus nerve, in the splanchnic nerve and in the pancreatic nerve. Each nerve was stimulated individually with biphasic, rectangular and current pulses (10 mA, 200 [my]s, 20 Hz). When stimuli were 10 mA or higher, measurable changes were observed during stimulation of both the vagus and the splanchnic nerves. In the splanchnic nerve, they were expressed as an increase in pressure in the bladder and as a tremor of the whole stomach. In the vagus nerve, they were expressed as a drastic decrease of arterial blood pressure and as abnormalities in the heart rate. In a further increase of stimuli to about 18 mA, the heart rate was slowed until it ceased as fatal brachicardia, asystolia and consequently hypotensia was occured.