Rosario Morello
ADVANCES IN ELECTROMYOGRAPHY APPLICATION: EGG AND PAIN ASSESSMENT

In this paper, the author deals with the advances of electromyographic technique. Nowadays, electromyographic measurements are used in several applications to assess specific pathologies. According to the muscle or myoelectric activity to be monitored, different methodologies have been defined such as, for example, electromyography, electrocardiography, electrogastrography, electroencephalography. Although such techniques require different procedures and instrumentation, each one is based on recording myoelectric signals due to muscle or nerve activity. The analysis of such signals allows physician to diagnose a specific pathology depending on arrhythmias and irregularities of the acquired waveform. In the paper, two promising and challenging applications of the electromyographic technique are described: electrogastrography to diagnose gastrointestinal disorders and electromyography for assessing pain in patients with chronic pain. The manuscript aims to call the attention on the still undiscovered potentialities of electromyographic technique and its use in new applications.

D. Bouchaala, O. Kanoun, N. Derbel
MINIMIZATION OF STRAY CAPACITANCES IN HOWLAND CURRENT SOURCE

Stray capacitances, due to e. g. limitations of layout and the use of active circuit elements, lead to limitations of the performance of bioimpedance devices at higher frequencies. The effects of stray capacitances can be avoided by several methods, such as Generalized Impedance Converter (GIC), Negative Impedance Converter (NIC) or external compensating operational amplifier.
In this work, the investigation of NIC and GIC for Howland current source shows that both methods are not suitable for multifrequency measurement system, because they need different adjustments of components for every frequency. The external compensation method is investigated with uncompensated and compensated operational amplifier. Simulation results show that the addition of compensation capacitor externally to the operational amplifier in Howland current source has good accuracy about 0.02 % at high frequencies up to 1MHz.

M. Peccarisi, T. De Marco, L. Spedicato, A. Greco, F. Conversano, D. Panetta, G. Guido, V. Bottai, P. Salvadori, S. Casciaro
IN VITRO ULTRASOUND CHARACTERIZATION OF HUMAN PROXIMAL FEMUR MICROSTRUCTURE AND COMPARISON WITH MICRO-CT DATA

An in vitro investigation based on Quantitative Ultrasound (QUS) has been carried out in this paper on a sample of human femoral head, aiming at microstructure characterization and bone quality assessment. Two QUS parameters, Integrated Reflection Coefficient (IRC) and Apparent Integrated Backscatter (AIB) were measured by accurately analyzing ultrasonic signals backscattered from the target bone when immersed in water and insonified at 2.25 MHz. In particular, US data were acquired from 22 different positions along the maximum section perpendicular to the axial direction (head-neck axis) of the target sample. The obtained data were compared with local structural properties gathered at each considered position from a high-resolution micro-computed tomography (microCT) scan of the same sample. A linear regression analysis showed an appreciable correlation between QUS parameters and some of the micro-structural parameters. As expected, IRC correlated better with cortical bone volume fraction (r = -0.53), and AIB with trabecular bone volume fraction (r = -0.60) and trabecular spacing (r = 0.47). These results are particularly encouraging in view of a possible clinical translation of the proposed approach for early osteoporosis diagnosis.

A. Greco, P. Pisani, G. Soloperto, M. D. Renna, F. Conversano, M. Muratore, S. Casciaro
COMPARISON BETWEEN ULTRASOUND FRAGILITY SCORE AND FRAX® FOR THE ASSESSMENT OF OSTEOPOROTIC FRACTURE RISK

The assessment of osteoporotic fracture risk requires the measurement of bone mineral density (BMD) on reference sites (hip and spine) and the evaluation of clinical risk factors (CRFs) for fracture. The Fracture Risk Assessment algorithm (FRAX ®), internationally recognized by official guidelines for osteoporotic patient management, represents a tool for estimating 10-year probability of hip and major fragility fractures by integrating CRFs and femoral neck BMD or T-score, when available. In this work we presented an innovative ultrasound (US)-based method for estimating fracture risk by means of a safe and radiation- free approach. From abdominal ultrasound scans performed on 64 female patients, we defined and quantified a new US diagnostic parameter named Fragility Score (F.S.), which estimates bone fragility. Obtained results showed an high Pearson correlation coefficient between fracture probabilities calculated by FRAX ® and F.S. (r up to 0.75 in the case of FRAX® estimates including femoral neck BMD and r = 0.71 in the case of FRAX® estimates based on femoral neck T-score). The present study demonstrated the feasibility of a novel US approach for fracture risk prediction and prevention, directly applicable on spine and independent from BMD measurements and CRF assessments. The proposed methodology could represent a valid alternative to both FRAX ® and BMD for early assessment of fracture risk.

S. Casciaro, M. D. Renna, F. Conversano, G. Soloperto, E. Casciaro, E. Quarta, A. Grimaldi , M. Muratore
CLINICAL EVALUATION OF A NOVEL ULTRASOUND-BASED METHODOLOGY FOR OSTEOPOROSIS DIAGNOSIS ON OVERWEIGHT AND OBESE WOMEN

Osteoporosis and overweight/obesity constitute major worldwide public health burdens that are associated with aging. The gold standard for osteoporosis diagnosis is currently represented by bone mineral density (BMD) measurement through dual-energy X-ray absorptiometry (DXA). However, DXA cannot be used for early diagnosis through population mass screenings due to ionizing radiation employment. Because of this, generally, only people considered at high risk of fracture (underweight women after the menopause) undergo to osteoporosis screening. In fact, a significant risk factor for fracture is the low body mass index (BMI), while the tendency to overweight or obesity delays osteoporosis onset. Nevertheless, a high proportion of women after the menopause develop intra-abdominal adiposity, which leads to metabolic disorders and osteoporosis. This paper describes the diagnostic accuracy of a novel ultrasound (US)-based method to perform spinal densitometry. The proposed innovative methodology is based on a combined analysis of both echographic images and “raw” radiofrequency US signals. The diagnostic output is represented by the same parameters provided by DXA (BMD, T-score, Z-score). The efficiency of the proposed methodology was evaluated on a cohort of 280 overweight or obese (BMI > 25 kg/m²) female patients in the age range 45-65 years. For 81.4% of the patients, US diagnosis (osteoporotic, osteopenic, healthy) was the same of the corresponding DXA one, showing the high accuracy of the proposed US technique, especially in the youngest patients (86.4% of correct diagnoses in the age range 45-50 y). A good correlation was also found between the diagnostic parameters provided by both US and DXA methods: all obtained values of Pearson coefficient (r) were within the interval 0.66-0.76 (p < 0.001). Then, this new non-ionizing approach to spinal bone densitometry has the potential for being extremely useful for early osteoporosis diagnosis through population mass screenings.