Journal of Mechanics in Medicine and Biology

Data mining techniques has been used as a recent trend for achieving diagnostics results, especially in medical fields such as kidney dialysis, skin cancer and breast cancer detection, and also biological sequences classification. Due to its ability to discover the relationship and pattern of the medical database, early detection or prediction of pathological conditions through mining has become feasible. This paper discusses the data mining approach for parametric evaluation to improve the treatment of kidney dialysis patient. The experimental result shows that classification accuracy using Association mining between the ranges 50–97.7% is obtained based on the dialysis parameter combination. Such a decision-based approach helps the clinician to decide the level of dialysis required for individual patient.

Background: Breast cancer is a common and dreadful disease in women. One in five cancers in Singaporean women is due to breast cancer. Breast health is every woman's right and responsibility. In average, every $100 spent on breast mammogram screening, an additional $33 was spent on evaluating possible false-positive results. Thermography, with its non-radiation, non-contact and low-cost basis has been demonstrated to be a valuable and safe early risk marker of breast pathology, and an excellent case management tool available today in the ongoing monitoring and treatment of breast disease. The surface temperature and the vascularization pattern of the breast could indicate breast diseases and early detection saves lives. To establish the surface isotherm pattern of the breast and the normal range of cyclic variations of temperature distribution can assist in identifying the abnormal infrared images of diseased breasts. Before these thermograms can be analyzed objectively via computer algorithm, they must be digitized and segmented. The authors present a method to segment thermograms and extract useful region from the background. Thermography could detect the presence of tumors much earlier and of much smaller size than mammography. This paper thus aims to develop an intelligent diagnostic system based on thermography for the detection of tumors in breast. Methods: We have examined about 50 normal, healthy female volunteers in Nanyang Technological University and 130 patients in Singapore General Hospital. We did the examinations for some of them continuously for two months. From these examinations, we obtained about 1000 thermograms for contact and 800 thermograms for non-contact approaches. Standard ambient conditions were observed for all examinations. The thermograms obtained were analyzed. The first step in processing these thermograms is image segmentation. Its aim is to discern the useful region from the background. In general, autonomous segmentation is one of the most difficult tasks in image processing. This step in the process determines the eventual success or failure of the analysis. In this work, two different techniques have been presented to extract the objects from the background. Results: After analyzing these thermograms and with reference to some relevant well-documented papers, we were able to classify the thermograms. The step is very useful in identifying the normal or suspected (abnormal) thermograms. A series of thermograms was studied with the help of the in-house developed computer software. On the basis of the anatomic and vascular symmetry, the surface temperature distributions of both left and right breasts were compared. The surface isotherm pattern of breasts can indicate the local metabolism and vascularity of the underlying tissues, and the change in local blood or glandular activities can be reflected in the surface temperature of breast. We evaluated the temperature distribution pattern and the menstrual cyclic variation of temperature with time. All these results can be used to detect breast cancer. Conclusion: Automatic identification of object and surface boundary of breast thermal images is a difficult and challenging task. Both the traditional snake and gradient vector flow snake failed to detect the boundary of these images successfully. In this work, a new method is proposed in conjunction with image pre-processing, image transition, image derivative, filtering and gradient vector flow snake. This novel method can easily detect the boundary of the breast thermal image with good agreement.

An aneurysm is a local enlargement of the vessel lumen due to the weakening of the wall material. We propose a mathematical model of the pulsatile blood flow through the system consisting of the cerebral artery and an aneurysm. The mathematical model is based on mass and energy conservation laws. It comprises non-linear rheological properties of the aneurysm and artery, and inertial and resistant properties of the blood flow. The model equations are analyzed by the methods of non-linear dynamics and they are solved numerically. Special attention is paid to the flow stability as a function of the aneurysmal and arterial material properties, the mean and oscillating arterial pressure, and the frequency of heart pulsations. The results of the work can be summarized as follows: (i) the model equations are stable at normal physiological conditions and developed aneurysms, (ii) with decreasing of the aneurysmal compliance, the aneurysmal volume pulsations increase and a limit point of flow stability is approached, (iii) the increased amplitude of the pulsatile pressure and the heart frequency cannot lead to flow instabilities.

Recent development of non-invasive and remote sensing modalities such as the Laser Doppler Perfusion Imager (LDPI) technology for probing the skin blood perfusion and its spatial variability over a region of interest, allows for detailed analysis of alterations in skin blood perfusion, with virtually no disturbance of the microcirculation under study. In this study, we have investigated perfusion flux pattern changes obtained from the abdominal area of 30 Chinese male patients (mean age of 26, presented only 2 typical cases) undergoing an acupuncture slimming course. The objective was to study the alterations in skin blood flux by detailed analysis of the Doppler images taken before, during which and after the insertion of needles. We explained the correlation of alterations of skin blood flux with the flow of Qi and the losses of body weight and body fat content. The purpose was to quantify a relationship between changes in perfusion flux pattern and the efficacy of weight loss through acupuncture. In conclusion, this study affirmed that skin blood perfusion flux values in the abdominal area were the highest, whilst the acupuncture needles were inserted. There is also evidence that the increased flux values occurred along the meridian channels of acupuncture, thereby acknowledging the flow of Qi in them. Hence, further clinical studies in the use of LDPI to investigate acupuncture with more subjects are warranted.

The paper presents a novel technique of nonlinear spectral analysis. This technique is based on the concept of generalized entropy of a given probability distribution, known as the Rényi entropy. This concept allows defining generalized fractal dimension of encephalogram (EEG) and determining fractal spectra of encephalographic signals. These spectra contain information of both frequency and amplitude characteristics of EEG and can be used together with well-accepted techniques of EEG analysis as an enhancement of the latter. Powered by volume visualization of the brain activity, the method provides new clues for understanding the mental processes in humans.

The arterial wall dynamics evaluation requires the assessment of its frequency-response. The aim was to apply an original methodology, to evaluate the arterial wall pressure-diameter frequency-response and elastic complex modulus, of human in vivo and in vitro common carotid arteries (CCA). CCA pressure, diameter and wall thickness were recorded. In vitro recordings were performed using pressure microtransducer (Konigsberg) and sonomicrometry, in 14 CCA segments (from donors). The in vivo recordings were obtained non-invasively by tonometry and mode-B echography in 10 normotensive patients, and in 10 hypertensive patients before and after 3 months of treatment with an ACE-inhibitor. A system modeling-identification approach was used to estimate the viscoelastic parameters: elastic, viscous and inertial indexes, and to perform an isofrequency analysis (up to 5Hz) of the incremental elastic modulus E_inc(jω) of the arterial wall. The new approach, proposed to evaluate the frequency-dependence of arterial wall mechanics, was applied satisfactorily.

The connection of vascular segments with different mechanical properties increases the risk of generating blood turbulent fluxes, and involves the development of complications such as atherosclerosis in the arterial vessels. The mechanical properties of arterial vessel of two different subjects, the donor and the recipient, were analyzed. To experimentally validate the effects of the arterial wall mechanical properties on blood fluxes, 352 patients who received kidney transplantation were studied, concerning the development of renal artery atherosclerotic stenosis. An anastomothic arterial stenosis was observed in 92% of transplanted patients with donor/recipient age difference > 15 years, and in 5.7% of transplanted patients with donor/recipient age difference ≤ 15 years. In conclusion, it is useful to give more consideration to the patient's age difference in organ and vessel transplantations.

The goal of this paper is to examine the trapezius muscle tone by measuring simultaneously using Myoton-2 myometer i.e., the natural oscillation frequency, stiffness and the elasticity of the trapezius muscle. With this method, the mechanical response of the muscle, to a short applied mechanical impulse, is registered by an acceleration probe. From the acquired damped natural oscillation waveform, the frequency (Hz), the stiffness (N/m) and the logarithmic decrement of damping (characterizing tissue's elasticity) are calculated, quantifying the functional state of the muscle. The trapezius muscle on both sides of the body was tested in twenty adult women by two investigators using the Myoton-2 myometer. During the measurements, the subjects were in a relaxed sitting position. The Bland and Altman graphical test, comparing the differences of the measurements of two investigators, was used for assessing the inter-observer repeatability. The registered values for the trapezius muscle tension, stiffness and elasticity are varying between the tested subjects, but the intra-class correlation coefficient (ICC) was near 1 for three muscular properties, showing that the variation within the subject (due to the investigator) is negligible, compared with the variation between the subjects.