Development of an AVF Stenosis Assessment Tool for Hemodialysis Patients Using Robotic Ultrasound System.

With the aging population and lifestyle changes, the number of hemodialysis (HD) patients increases year by year. The arteriovenous fistula (AVF) is the gold standard vascular access used to access the blood for HD treatment. Since the status of stenosis affects HD efficiency, current clinical practices usually use a Doppler ultrasound imaging system to assess the parameters of the stenosis, such as the degree of stenosis (DOS). Unfortunately, this is a very time-consuming task. Furthermore, it is difficult to stably maintain the ultrasound probe for a prolonged period to give doctors clearer or reproducible images. In this study, a robotic ultrasound system (RUS) with ultrasound sequential imaging analysis was designed to evaluate the DOS of the AVF. The sequential imaging analysis was capable of image smoothing and vessel boundary detection. It enabled clinicians to mark the thickness of the plaque for further processing. Finally, the system was used to reconstruct 3D models of fistulas and calculated the DOS for clinical assessment. We also designed a pressure sensing module attached to the ultrasound probe to prevent the probe from coming loose, vibrating, and exerting abnormal pressure on the skin. In the phantom test, the results showed that the error of the DOS that was calculated by RUS was less than 3%. The results of clinical trials obtained from ten patients show that the error between the RUS and clinicians' measurement was about 10% and had a highly linear correlation (R Square > 0.95). In addition, the reproducibility error was about 3% and could effectively save about 46% of the time during clinical examinations.

Adaptive network-based fuzzy inference system for assessment of lower limb peripheral vascular occlusive disease.

Detecting lower limb peripheral vascular occlusive disease (PVOD) early is important for patients to prevent disabling claudication, ischaemic rest pain and gangrene. According to previous research, the pulse timing and shape distortion characteristics of photoplethysmography (PPG) signals tend to increase with disease severity and calibrated amplitude decreases with vascular diseases. However, this is not a reliable method of evaluating the condition of PVOD because of noise effect. In this paper, an adaptive network-based fuzzy inference system (ANFIS) is proposed to assess lower limb PVOD based on PPG signals. PPG signals are non-invasively recorded from the right and left sides at the big toe sites from twenty subjects, including normal condition (Nor), lower-grade disease (LG), and higher-grade disease (HG) groups. The number of each group is 10, 8 and 2 respectively, and the ages ranged from 24 to 65 years. With the time-domain technique, the parameters for the absolute bilateral differences (right-to-left side of foot) in pulse delay and amplitude were extracted for analyzing ANFIS. The results indicated that ANFIS based on three timing parameters base bilateral differences, including ΔPTTf and ΔPTTp, and ΔRT has a high rate and noise tolerance of PVOD assessment.

Development of a telecare system based on ZigBee mesh network for monitoring blood pressure of patients with hemodialysis in health care centers.

In Taiwan, the number of the patients needing dialysis increases rapidly in recent years. Because there is risk in every hemodialysis session, monitoring physiological status, such as blood pressure measurement every 30 min to 1 h is needed during about 4 h hemodialysis process. Therefore, an assisted measurement on blood pressure is needful in dialysis care centers. Telecare system (TCS) is regarded as one of important technique in the medical care. In this study, we utilized ZigBee wireless technique to establish a mesh network for monitoring blood pressure automatically and data storage in medical record system for display and further analysis. Moreover, while the blood pressure exceeds the normal range, the system could send a warning signal to remind, or inform the relatives and clinicians in health care center through the personal handy-phone system (PHS) immediately. The proposed system provides an assisted device for monitoring patients' blood pressure during hemodialysis process and saving medical manpower.

Implementation of a burn scar assessment system by ultrasound techniques.

Tissue injury and its ensuing healing process cause scar formation. In addition to physical disability, the subsequent disfigurements from burns often bring negative psychological impacts on the survivors. Scar hypertrophy and contracture limit the joint motion and body function of the patient. With fast development of the current available technologies regarding the scar therapies, not only the process of wound healing has to be focused, but also the cosmetic and functional outcomes need to be emphasized. Therefore, proper evaluation and assessment of the healing process to nil scar status is highly recommended. However, the currently employed tools for scar evaluation are mostly subjective. For example, Vancouver General Hospital (VGH) scar index uses color, pigmentation, vascularity, pliability, and depth of the scar as dependent variables for scar evaluation. These parameters only estimate the superficial surface of the scar, but they can not evaluate the deeper tissue within dermis. Ultrasound is a safe, inexpensive, and multifunctional technique for probing tissue characteristics. In addition, its resolution is not inferior to other measurement techniques. Although 3D-ultrasound is available in clinical application, it's still not widely used in scar evaluation because of its high cost. In this study, we proposed a system for scar assessment using B-mode ultrasonic technique. By utilizing the reconstruction methods to search the scar border, many characteristic parameters, including depth, area and volume, can be estimated. The proposed method is useful in assisting the clinician to evaluate the treatment effect and to plan further therapeutic strategy more objectively. In this report, the quantitative assessment system was used to evaluate the scar of a seriously burned patient. In order to verify the reliability of systematic reconstruction method, we constructed a phantom to imitate the scar tissue. The results show that it can achieve more than 90% in accuracy.