M Ferrari

Università degli Studi di Brescia, Brescia, Lombardy, Italy

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Publications (84)88.24 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Ultrasound (US) imaging offers advantages over other imaging modalities and has become the most widespread modality for many diagnostic and interventional procedures. However, traditional 2D US requires a long training period, especially to learn how to manipulate the probe. A hybrid interactive system based on mixed reality was designed, implemented and tested for hand-eye coordination training in diagnostic and interventional US.
    International Journal of Computer Assisted Radiology and Surgery 09/2014; · 1.36 Impact Factor
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    ABSTRACT: In this paper, a wireless temperature measurement system powered by energy harvesting from human motion is presented. The user force exerted on the hand-crank ElectroMagnetic (EM) device is converted into electricity. The electrical energy is stored into multiple capacitors by the proposed active power management circuit with the Sequential Charging of the Storage Capacitors network (SCSC). With an applied force of about 29.4 N over 2 cm, 27.5 mJ of energy are stored and used to power the wireless temperature sensor module. The module performs a noncontact temperature measurement, shows the reading on an LCD display, and sends the temperature data over a wireless-UART link at 433 MHz to a host PC.
    Proceedings of the 1st International Workshop on Energy Neutral Sensing Systems; 11/2013
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    ABSTRACT: In this study we evaluated the diagnostic performance of (99m)Tc-HMPAO-leucocyte ((99m)Tc-HMPAO-WBC) scintigraphy in a consecutive series of 55 patients (46 men and 9 women, mean age 71 ± 9 years, range 50 - 88 years) with a suspected late or a low-grade late vascular prosthesis infection (VPI), also comparing the diagnostic accuracy of WBC with that of other radiological imaging methods. All patients suspected of having VPI underwent clinical examination, blood tests, microbiology, US and CT, and were classified according to the Fitzgerald criteria. A final diagnosis of VPI was established in 47 of the 55 patients, with microbiological confirmation after surgical removal of the prosthesis in 36 of the 47. In the 11 patients with major contraindications to surgery, the final diagnosis was based on microbiology and clinical follow-up of at least 18 months. (99m)Tc-HMPAO-WBC planar, SPECT and SPECT/CT imaging identified VPI in 43 of 47 patients (20 of these also showed infection at extra-prosthetic sites). In the remaining eight patients without VPI, different sites of infections were found. The use of SPECT/CT images led to a significant reduction in the number of false-positive findings in 37 % of patients (sensitivity and specificity 100 %, versus 85.1 % and 62.5 % for stand-alone SPECT). Sensitivity and specificity were 34 % and 75 % for US, 48.9 % and 83.3 % for CT, and 68.1 % and 62.5 % for the FitzGerald classification. Perioperative mortality was 5.5 %, mid-term mortality 12 %, and long-term mortality 27 %. Survival rates were similar in patients treated with surgery and antimicrobial therapy compared to patients treated with antimicrobial therapy alone (61 % versus 63 %, respectively), while infection eradication at 12 months was significantly higher following surgery (83.3 % versus 45.5 %). (99m)Tc-HMPAO-WBC SPECT/CT is useful for detecting, localizing and defining the extent of graft infection in patients with late and low-grade late VPI with inconclusive radiological findings. (99m)Tc-HMPAO-WBC SPECT/CT might be used to optimize patient management.
    European Journal of Nuclear Medicine 10/2013; · 4.53 Impact Factor
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    ABSTRACT: The purpose of this in vitro study was to clinically assess the feasibility of a three-dimensional (3D) electromagnetic (EM) navigator, including sensorized catheters and guidewires, to determine any reduction in radiation dose and contrast medium injection. The study was performed using a navigator prototype developed at the EndoCAS center. The system includes catheters and guidewires simultaneously tracked with an EM localizer (Aurora, Northern Digital, Waterloo, Canada). Tests were performed on a commercial abdominal aortic aneurysm model. Fifteen operators were asked to cannulate renal arteries using the conventional fluoroscopic guidance and the EM navigator without fluoroscopic support. Each trial was video-recorded and analyzed for timing and success of completing the cannulation task by two blinded and independent observers. Performances were also qualitatively evaluated using the Imperial College Endovascular Cannulation Scoring Tool (IC3ST). Moreover, a questionnaire was administered to participants to evaluate the navigator potentialities. Quantitative analysis results show no significant difference between the fluoroscopic and EM guidance regarding the total procedure time (median 2.36 minutes [interquartile range {IQR} = 1.26-4.7) vs. 2.95 min [IQR = 1.35-5.38], respectively; p = .93); number of total hits with catheter/guidewire tip to vessels wall (median 5.50 [IQR = 2.00-10.00] vs. 3.50 [IQR = 2.50-7.00], respectively; p = .65); and number of attempts at cannulation (median 4.0 [IQR = 2.00-5.00] vs. 4.0 [IQR = 2.00-5.00], respectively; p = .72]. Moreover, there was no significant difference between the IC3ST score obtained using the EM navigator and the traditional method (average 22.37 [STD = 7.95] vs. 21.58 [STD = 6.86]; p = .92). Finally, questionnaire results indicate a general agreement concerning the navigator usefulness, which clearly shows the positions of instruments inside the 3D model of the patient's anatomy. Participants also agreed that the navigator can reduce the amount of contrast media delivered to the patient, as well as fluoroscopy time. This work provides proof of concept that simultaneous EM navigation of guidewires and catheters is feasible without the use of live fluoroscopic images.
    European journal of vascular and endovascular surgery: the official journal of the European Society for Vascular Surgery 10/2013; · 2.92 Impact Factor
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    ABSTRACT: Vessel lumen centerline extraction is important for intraoperative tracking of abdominal vessels and guidance of endovascular instruments. Three-dimensional ultrasound has gained increasing acceptance as a safe and convenient surgical image guidance modality. We aimed to optimize vascular centerline detection and tracking in 3D ultrasound. To overcome the intrinsic limitation of low ultrasound image quality, an active contour method (snake) was used to track changes in vessel geometry. We tested two variants of a classic snake using the image gradient and gradient vector field (GVF) as external forces. We validated these methods in liver ultrasound images of 10 healthy volunteers, acquired at three breath-holding instances during the exhalation phase. We calculated the distances between the vessel centerlines as detected by algorithms and a gold standard consisting of manual annotations performed by an expert. Both methods (GVF and image gradient) can accurately estimate the actual centerlines with average Euclidean distances of 0.77 and 1.24 mm for GVF and gradient, respectively. Both methods can automatically follow vessel morphology and position changes. The proposed approach is feasible for liver vessel centerline extraction from 3D ultrasound images. The algorithm can follow the movement of the vessels during respiration; further improvements of hardware components are needed for a real-time implementation.
    International Journal of Computer Assisted Radiology and Surgery 07/2013; · 1.36 Impact Factor
  • D. Alghisi, M. Ferrari, V. Ferrari
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    ABSTRACT: This paper presents an autonomous battery-less temperature measurement system powered on-demand by human action. The conversion between the human action and electrical energy is provided by an hand-held electromagnetic (EM) converter intentionally activated by the user. The AC voltage generated by the EM converter has time-varying amplitude and frequency and is rectified by a voltage doubler active rectifier circuit. The energy harvested is stored into multiple capacitors by the innovative Sequential Charging of Storage Capacitors (SCSC) technique. With a force of about 29.4 N over 2 cm applied to the EM converter, the power management circuit is able to extract an energy of 27.5 mJ and power the noncontact temperature measurement system for about 17 s.
    Emerging Technologies & Factory Automation (ETFA), 2013 IEEE 18th Conference on; 01/2013
  • M. Ferrari, F. Cerini, V. Ferrari
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    ABSTRACT: This work proposes and experimentally validates an autonomous battery-less sensor module based on off-the-shelf electronics powered by a multi-beam piezoelectric energy converter that exploits impact to widen the harvesting bandwidth at low frequency. The module manages the converted energy, interfaces two sensors and periodically sends the measurement signals over a radio-frequency (RF) link. The architecture and principle have been experimentally validated on a fabricated proof-of-concept prototype. The solution that exploits impact increases the overall rms output voltage of the converter of up to 35% and widens the useful bandwidth toward lower frequencies of up to 50% over the no-impact condition at parity of mechanical excitation. In the tested experimental conditions, the prototype features a typical time interval between measurement-and-transmission events of a few seconds, with event durations of the order of tens of milliseconds, corresponding to an operation duty cycle of about 1%. The average power consumption during transmission is of the order of 35 mW with an operative range of 25 m in laboratory environment.
    Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS & EUROSENSORS XXVII), 2013 Transducers & Eurosensors XXVII: The 17th International Conference on; 01/2013
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    ABSTRACT: BACKGROUND: The da Vinci robotic surgical telemanipulator has been utilized in several surgical specialties for varied procedures, and the users' experiences have been widely published. To date, no detailed system technical analyses have been performed. METHODS: A detailed review was performed of all publications and patents about the technical aspects of the da Vinci robotic system. RESULTS: Published technical literature on the da Vinci system highlight strengths and weaknesses of the robot design. While the system facilitates complex surgical operations and has a low malfunction rate, the lack of haptic (especially tactile) feedback and collisions between the robotic arms remain the major limitations of the system. Accurate, preplanned positioning of access ports is essential. CONCLUSION: Knowledge of the technical aspects of the da Vinci robot is important for optimal use. We confirmed the excellent system functionality and ease of use for surgeons without an engineering background. Research and development of the surgical robot has been predominant in the literature. Future trends address robot miniaturization and intelligent control design. Copyright © 2012 John Wiley & Sons, Ltd.
    International Journal of Medical Robotics and Computer Assisted Surgery 11/2012; · 1.49 Impact Factor
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    ABSTRACT: BACKGROUND: Currently, pedicle screws are positioned using a free-hand technique or under fluoroscopic guidance, with error in the range 10-40%, depending on the skill of the surgeon. METHODS: After spine CT acquisition, each vertebra is segmented and the surgeon plans screw positioning in a virtual environment, then the template is designed around the chosen trajectories. This design is based on surgical and mechanical considerations to obtain an optimal solution to guarantee template stability, simple positioning and minimized intervention invasiveness. In vitro evaluation on synthetic spine models and ex vivo animal tests on porcine specimens were performed, with the insertion of 28 Kirschner wires. RESULTS: During the in vitro tests, all the surgeons rendered positive evaluations regarding the device and considered template placement to be easy. Ex vivo tests were evaluated by CT examination, which showed that 96.5% of the Kirschner wires had been correctly inserted. CONCLUSIONS: The proposed solution is a promising, simple, highly precise, low-cost solution to safely performing posterior stabilization. Such a solution would be of interest even in hospitals in which a few spine interventions are performed per year, and for which it is not reasonable to purchase the equipment required for robotic or navigated approaches. Copyright © 2012 John Wiley & Sons, Ltd.
    International Journal of Medical Robotics and Computer Assisted Surgery 05/2012; · 1.49 Impact Factor
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    ABSTRACT: Endovascular procedures are nowadays limited by difficulties arising from the use of 2D images and are associated with dangerous X-ray exposure and the injection of nephrotoxic contrast medium. An electromagnetic navigator is proposed to guide endovascular procedures with reduced radiation dose and contrast medium injection. Five DOF electromagnetic sensors are calibrated and used to track in real time the positions and orientation of endovascular catheters and guidewires, while intraoperative 3D rotational angiography is used to acquire 3D models of patient anatomy. A preliminary prototype is developed to prove the feasibility of the system using an anthropomorphic phantom. The spatial accuracy of the system was evaluated during 70 targeting trials obtaining an overall accuracy of 1.2 ± 0.3 mm; system usability was positively evaluated by three surgeons. The strategy proposed to sensorize endovascular instruments paves the way for the development of surgical strategies with reduced radiation dose and contrast medium injection. Further in vitro, animal and clinical experiments are necessary for complete surgical validation.
    International Journal of Medical Robotics and Computer Assisted Surgery 02/2012; 8(3):300-10. · 1.49 Impact Factor
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    ABSTRACT: Among the main vibration-to-electricity conversion systems, resonant harvesters suffer from a series of strong limits like their narrow frequency response and poor output power at small scale. Most of all, realistic vibration sources are variable in time and abundant at relatively low frequencies. Nonlinear vibration harvesters, on the other hand, are more attractive, thanks to their large bandwidth response and flexibility to convert kinetic energy of the natural frequency of the sources. In particular, bistable oscillators have been proven to show higher global performances when excited by random vibrations. In this paper, such an approach is investigated for piezoelectric beams by exerting an increasing axial compression. An advantage of this technique is the absence of magnetic forces to create bistable dynamics. A thin piezoelectric axially loaded beam is theoretically modelled and experimentally investigated under wideband random vibrations. In the buckled configuration, the device exhibits superior power generation over a large interval of resistive load, with gains up to more than a factor of ten compared to the unbuckled state. The numerical model and experimental results are in good qualitative agreement.
    Smart Materials and Structures 02/2012; 21(3):035021. · 2.02 Impact Factor
  • Proceedings Eurosensors 2012; 01/2012
  • M Ferrari, D Alghisi, M Baù, V Ferrari
    Procedia Engineering 01/2012; 47:410 - 413.
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    ABSTRACT: Power harvesters from mechanical vibrations are commonly linear mechanical resonators that are most effective when excited at resonance. Differently, under wideband vibrations, linear converters are suboptimal. A nonlinear converter is here proposed that implements nonlinearity and bistability by employing a single external magnet, in order to improve conversion effectiveness while simplifying device fabrication. The converter is composed of a piezoelectric bimorph on a ferromagnetic cantilever. The fabrication technology is based on the screen printing of a PZT low-curing-temperature paste on harmonic steel substrate. The ferromagnetic cantilever converter, under proper coupling with the external magnet, bounces between two stable states when excited by random vibrations and generates an electric output via the piezoelectric effect. According to theoretical predictions, when bistable behaviour is present, experimental results demonstrate an improvement of about 400% of the rms voltage generated by the converter with respect to the linear case.
    Sensors and Actuators A-physical - SENSOR ACTUATOR A-PHYS. 12/2011;
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    ABSTRACT: According to literature evidence, simulation is of the utmost importance for training and innovative surgical strategies assessment. At present commercial physical simulators are limited to single or only a few anatomical structures and these are often just standard anatomies. This paper describes a strategy to produce patient-specific abdominal silicone organs with realistic shapes and colors, starting from radiological images. Synthetic organs can be assembled in a complex physical simulator or, if paired with electromagnetic sensors, in a hybrid environment (mixed reality) to quantify deformations caused by surgical action. A physical trunk phantom with liver, gallbladder, pancreas and a sensorized stomach has been developed. It is coupled with consistent radiological images and a 3D model of the entire upper abdomen. The simulator has been evaluated in quantitative and qualitative terms to quantify its accuracy and utility, respectively. This simulator can be used in the field of abdominal surgery to train students and as a testing environment to assess and validate innovative surgical technologies.
    International Journal of Medical Robotics and Computer Assisted Surgery 06/2011; 7(2):202-13. · 1.49 Impact Factor
  • M. Bau, M. Ferrari, V. Ferrari, E. Tonoli
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    ABSTRACT: A technique for contactless readout of AT-cut quartz resonator sensors is proposed and validated. The technique is based on the separation in time of the excitation and detection phases, exploiting the sensing of the transient response of the resonator. An external primary coil is electromagnetically air-coupled to a secondary coil connected to the electrodes of the resonator. During the excitation phase the fundamental thickness shear mode of the resonator is excited, while in the detection phase the excitation signal is turned off and the transient response of the resonator is contactless sensed by measuring the voltage induced back across the primary coil. A lumped-element equivalent circuit has been studied in order to model the interrogation principle. Experimental results validate the theoretical model and show the successful detection of relative humidity changes by a quartz resonator sensitized with a hygroscopic coating. More generally the proposed technique can be exploited for the measurement of physical or chemical quantities affecting the resonant response of quartz resonator sensors.
    01/2011;
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    ABSTRACT: Several kinds of energy are available in the environment such as sunlight power, thermal gradients, wind, rain, tides, acoustic, and mechanical vibrations. This energy can be exploited to power electronic devices by means of suitable conversion mechanisms. Specifically, in the case of wearable device the need for onsite energy production emerges for the sake of both battery recharge and powering of sensors and electronics. In this chapter a review of power harvesting methodology is presented along with two examples of devices implementing advanced energy harvesting. Keywordsenergy harvesting-kinetic energy-piezoelectric-non linear mechanism-MEMS
    10/2010: pages 97-113;
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    ABSTRACT: A piezoelectric multifrequency converter array intended for energy harvesting from broadband vibrations to power autonomous sensors and two different configurations of multi-input rectifier circuits are presented. The converter array is composed of multiple bimorph cantilevers with different natural frequencies fabricated by screen-printed PZT films on steel. In the two proposed rectifier circuits, the converters of the array are connected in parallel-like and series-like configurations, respectively. The effect produced on the harvesting performances for the two configurations is analyzed and validated by experimental results on the fabricated array. At parity of mechanical excitation, the series-like configuration can provide a marked increase in the overall output voltage over the parallel-like configuration.
    Sensor Device Technologies and Applications (SENSORDEVICES), 2010 First International Conference on; 08/2010
  • M. Ferrari, V. Ferrari, D. Marioli
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    ABSTRACT: This work proposes an interface circuit which exploits a compact implementation of impedance measurement to innovatively analyze a quartz crystal resonator (QCR) sensor across multiple-harmonic overtones. The system measures the real and imaginary parts of the sensor electrical admittance, from which the series resonant frequency and the motional resistance are derived for each overtone. By probing the resonator at multiple-harmonic modes, enhanced sensing capabilities can be conveniently achieved because a larger set of parameters can be measured with a single sensor. Experimental tests run with 5-MHz QCR sensors on which microdroplets of a sugar–water solution were deposited by a piezoelectric microdispenser show that the response patterns measured across different harmonics can be put in relation with the changes in the acoustic wavelength into the loading medium.
    Sensors and Actuators B-chemical - SENSOR ACTUATOR B-CHEM. 01/2010; 146(2):489-494.
  • Conf Proc ICABB, International Conference on Applied Bionics and Biomechanics, Venice, Italy; 01/2010

Publication Stats

414 Citations
88.24 Total Impact Points

Institutions

  • 2004–2013
    • Università degli Studi di Brescia
      • Department of Information Engineering
      Brescia, Lombardy, Italy
  • 1988–2012
    • Università di Pisa
      • Department of Clinical and Experimental Medicine
      Pisa, Tuscany, Italy
  • 2008
    • Polytechnical University of Valencia
      • Department of Electronic Engineering
      Valencia, Valencia, Spain
  • 2007
    • Stanford University
      Palo Alto, California, United States
    • University of Valencia
      Valenza, Valencia, Spain
  • 2004–2005
    • Azienda Ospedaliero-Universitaria Pisana
      Pisa, Tuscany, Italy
  • 2003–2004
    • Università degli studi di Parma
      Parma, Emilia-Romagna, Italy
  • 2002–2004
    • Brescia University
      Kenosha, Wisconsin, United States