[Quality Control Test of Transcranial MRI-guided Focused Ultrasound Treatment System before Surgery].

OBJECTIVE: To investigate the pre-treatment preventive maintenance and quality control procedure of MRI system and transcranial MRI-guided focused ultrasound (TcMRgFUS) treatment system by monitoring quality control of these two systems. METHODS: The general performance index and image quality control index of MRI system, as well as the quality assurance program of TcMRgFUS EXABLATE 4000 system were tested and recorded. RESULTS: The general performance index and image quality control index of MRI system met requirements. CONCLUSIONS: Through system detection, the system performance could be monitored, ensuring the accuracy and safety of surgery.

A comparative study of the efficacy of ultrasonics and extracorporeal shock wave in the treatment of tennis elbow: a meta-analysis of randomized controlled trials.

BACKGROUND: Tennis elbow or lateral epicondylitis is a common source of pain among craftsmen. Although it cannot be completely resolved, extracorporeal shock wave therapy (ESWT) and ultrasonics (US) have been found to be effective for tennis elbow as highlighted in previously published randomized controlled trials (RCTs) and reviews. However, the efficacy of these two therapies in treating tennis elbow is unknown. This meta-analysis compares the effectiveness of ESWT and US in relieving pain and restoring the functions of tennis elbow following tendinopathy. METHODS: RCTs published in the PubMed, Embase, Cochrane Library, and SpringerLink databases comparing ESWT and US in treating tennis elbow were identified by a software and manual search. The risk of bias and clinical relevance of the included studies were assessed. Publication bias was explored using funnel plot and statistical tests (Egger's test and Begg's test). The major outcomes of the studies were analyzed using the Review Manager 5.3. RESULTS: Five RCTs comprising five patients were included in the present meta-analysis. The results revealed a significantly lower VAS score of pain in the ESWT group (1 month: MD = 4.47, p = 0.0001; 3 months: MD = 20.32, p < 0.00001; and 6 months: MD = 4.32, p < 0.0001) compared to US. Besides, the grip strength was markedly higher 3 months after the intervention in ESWT (MD = 8.87, p < 0.00001) than in the US group. Although no significant difference was observed in the scores of the elbow function after 3 months of treatment (SMD = 1.51, p = 0.13), the subjective scores of elbow functions were found to be better in the ESWT group (SMD = 3.34; p = 0.0008) compared to the US group. CONCLUSIONS: Although there was no significant difference in the elbow function evaluation scores between ESWT and US, the superiority of the ESWT group in the VAS of pain (both at 1 month, 3 months, and 6 months follow-ups) raised grip strength in ESWT group and the scores for subjective evaluation of efficacy indicated that ESWT offers more effective therapy for lateral epicondylitis than US therapy.

Determination of physiotherapy ultrasound beam quality parameters from images derived using thermochromic material.

The evaluation of the performance of nine physiotherapy ultrasound transducers used clinically was performed in the hospital environment using an acoustically absorbing thermocromic tile developed at the National Physical Laboratory (UK). The method consists of exposing an acoustic absorber tile, part of which contains a thermochromic pigment, to the ultrasonic beam, thereby forming an image of the intensity profile of the transducer. Images acquired using thermochromic materials were postprocessed in order to estimate effective radiating area (ERA) and beam nonuniformity ratio (BNR) for ultrasound transducers operating within the frequency range from 1.0 to 3.3 MHz, and nominal applied intensities in the range of 1-2W/cm2. Results of our measurements have shown that thermocromic tile can be used for quality control of ultrasound transducers in the hospital environment. Experimental results show that proposed method can be used to distinguish highly non - uniform ultrasound beams with high value of BNR. Influence of exposure duration on obtained ERA and BNR values was also analysed. Our results show that values for ERA increase with insonation time, while BNR values decrease. In order to compare our results with theory we have estimated temperature rise in thermochromic material experimentally and compare it with theoretical prediction.

Comparison of high-frequency and ultrahigh-frequency probes in chronic inflammatory demyelinating polyneuropathy.

OBJECTIVES: High-frequency ultrasound (HFUS 18-20 MHz) performed on patients with chronic inflammatory demyelinating polyneuropathy (CIDP) shows a focal enlargement, particularly in the proximal segments of upper-arm motor nerves. Ultrahigh frequency ultrasound (UHFUS 30-70 MHz), having a higher spatial resolution, enables a better characterization of nerve structures. The aim of this study was to compare the two ultrasound probes in the evaluation of motor nerve characteristics in CIDP patients. METHODS: Eleven patients with definite or probable CIDP underwent an ultrasound evaluation of median and ulnar nerves, bilaterally. Nerve and fascicle cross-sectional area (CSA), vascularization, and echogenicity were assessed. RESULTS: Nerve and fascicle CSA were increased in the proximal segments, especially in the median nerve, in 9/11 patients and in 10/11 patients at the HFUS and UHFUS evaluations, respectively. A statistically significant difference between CSA values obtained with the two probes was found only for fascicle values. UHFUS allowed for a more precise estimation of fascicle size and number than the HFUS. We were able to identify nerve vascularization in 4/11 patients at UHFUS only. CONCLUSION: UHFUS gives more detailed information on the changes in the internal nerve structure in CIDP patients. In particular, it permits to better characterize fascicle size and morphology, and to have a precise estimation of their number. Its frequency range also allows to evaluate nerve vascularization. SIGNIFICANCE: Ultrasound evaluation could become an adjunctive diagnostic tool for CIDP. Further studies are needed to validate the examined parameters as biomarkers for the evaluation and follow-up of CIDP patients.

The Future of Brain Stimulation Treatments.

Trends in brain stimulation include becoming less invasive, more focal, and more durable with less toxicity. Several of the more interesting new potentially disruptive technologies that are just making their way through basic and sometimes clinical research studies include low-intensity focused ultrasound and temporally interfering electric fields. It is possible, and even likely, that noninvasive brain stimulation may become the dominant form of brain treatments over the next 20 years. The future of brain stimulation therapeutics is bright.

Survey of ultrasound practice amongst podiatrists in the UK.

BACKGROUND: Ultrasound in podiatry practice encompasses musculoskeletal ultrasound imaging, vascular hand-held Doppler ultrasound and therapeutic ultrasound. Sonography practice is not regulated by the Health and Care Professions Council (HCPC), with no requirement to hold a formal qualification. The College of Podiatry does not currently define ultrasound training and competencies.This study aimed to determine the current use of ultrasound, training received and mentorship received and/or provided by podiatrists using ultrasound. METHODS: A quantitative study utilising a cross-sectional, on-line, single-event survey was undertaken within the UK. RESULTS: Completed surveys were received from 284 podiatrists; 173 (70%) use ultrasound as part of their general practice, 139 (49%) for musculoskeletal problems, 131 (46%) for vascular assessment and 39 (14%) to support their surgical practice. Almost a quarter (n = 62) worked for more than one organisation; 202 (71%) were employed by the NHS and/or private sector (n = 118, 41%).Nearly all (93%) respondents report using a hand-held vascular Doppler in their daily practice; 216 (82%) to support decisions regarding treatment options, 102 (39%) to provide diagnostic reports for other health professionals, and 34 (13%) to guide nerve blocks.Ultrasound imaging was used by 104 (37%) respondents primarily to aid clinical decision making (n = 81) and guide interventions (steroid injections n = 67; nerve blocks n = 39). Ninety-three percent stated they use ultrasound imaging to treat their own patients, while others scan at the request of other podiatrists (n = 28) or health professionals (n = 18). Few use ultrasound imaging for research (n = 7) or education (n = 2).Only 32 (11%) respondents (n = 20 private sector) use therapeutic ultrasound to treat patients presenting with musculoskeletal complaints, namely tendon pathologies.Few respondents (18%) had completed formal post-graduate CASE (Consortium for the Accreditation of Sonographic Education) accredited ultrasound courses.Forty (14%) respondents receive ultrasound mentorship; the majority from fellow podiatrists (n = 17) or medical colleagues (n = 15). Over half (n = 127) who do not have ultrasound mentorship indicated they would like a mentor predominantly for ultrasound imaging. Fifty-five (19%) report they currently provide ultrasound mentorship for others. CONCLUSIONS: Understanding the scope of ultrasound practice, the training undertaken and the requirements for mentorship will underpin the development of competencies and recommendations defined by the College of Podiatry to support professional development and ensure safe practice.

Focused ultrasound transducer spatial peak intensity estimation: a comparison of methods.

Characterisation of the spatial peak intensity at the focus of high intensity focused ultrasound transducers is difficult because of the risk of damage to hydrophone sensors at the high focal pressures generated. Hill et al (1994 Ultrasound Med. Biol. 20 259-69) provided a simple equation for estimating spatial-peak intensity for solid spherical bowl transducers using measured acoustic power and focal beamwidth. This paper demonstrates theoretically and experimentally that this expression is only strictly valid for spherical bowl transducers without a central (imaging) aperture. A hole in the centre of the transducer results in over-estimation of the peak intensity. Improved strategies for determining focal peak intensity from a measurement of total acoustic power are proposed. Four methods are compared: (i) a solid spherical bowl approximation (after Hill et al 1994 Ultrasound Med. Biol. 20 259-69), (ii) a numerical method derived from theory, (iii) a method using measured sidelobe to focal peak pressure ratio, and (iv) a method for measuring the focal power fraction (FPF) experimentally. Spatial-peak intensities were estimated for 8 transducers at three drive powers levels: low (approximately 1 W), moderate (~10 W) and high (20-70 W). The calculated intensities were compared with those derived from focal peak pressure measurements made using a calibrated hydrophone. The FPF measurement method was found to provide focal peak intensity estimates that agreed most closely (within 15%) with the hydrophone measurements, followed by the pressure ratio method (within 20%). The numerical method was found to consistently over-estimate focal peak intensity (+40% on average), however, for transducers with a central hole it was more accurate than using the solid bowl assumption (+70% over-estimation). In conclusion, the ability to make use of an automated beam plotting system, and a hydrophone with good spatial resolution, greatly facilitates characterisation of the FPF, and consequently gives improved confidence in estimating spatial peak intensity from measurement of acoustic power.

The Dynatron Solaris® Ultrasound Machine: Slower Heating Than Textbook Recommendations at 3 MHz, 1.0 W/cm2.

CONTEXT: Therapeutic ultrasound clinical parameters are provided in many modality textbooks based on research performed with the Omnisound brand. Literature exists to support variability in heating rates with different manufacturers. It is unknown if the Dynatron Solaris heats at rates consistent with textbook recommendations. OBJECTIVE: Determine the rate of tissue-temperature increases in the medial triceps surae with the Dynatron Solaris® 708 ultrasound unit. DESIGN: 3 × 13 repeated measures. Independent variables were tissue depth (1.0, 1.75, and 2.5 cm) and time (13 time periods throughout the treatment). SETTING: Research laboratory. PARTICIPANTS: 30 healthy volunteers (female = 11, male = 19; age 21.30 ± 1.95 y; adipose thickness = 0.54 ± 0.15 cm). INTERVENTION:  Three thermocouples were inserted into the medial triceps surae at 1.0, 1.75, and 2.5-cm depths. A continuous 3-MHz, 1.0-W/cm2 for 20 minutes ultrasound treatment was performed with a Dynatron Solaris 708 machine. MAIN OUTCOME MEASURES: Intramuscular tissue-temperature increases at each depth throughout the 20-min treatment. RESULTS: There was a significant main effect of depth (F2,52 = 29.76, P < 0.001) and time (F12,312 = 181.59, P < .001) and a significant interaction between times and depths (F24,624 = 15.49, P < .001). The 1.0-cm depth increased 4.22 ± 1.58°C in 6 min (0.70°C/min rate), the 1.75-cm depth increased 3.93 ± 1.94°C in 10 min (0.39°C/min rate), and the 2.5-cm depth increased 3.60 ± 1.86°C in 20 min (0.18°C/min rate). CONCLUSIONS: The rate of tissue-temperature increase varied at each depth and the 1.0-cm depth was the only rate similar to textbooks. Clinicians will not reach tissue-temperature goals using Omnisound textbook parameters on the Dynatron Solaris 708 at depths greater than 1.0 cm, which may affect clinicians, educators, and state-certification exams.

Use of Noncontact Low-Frequency Ultrasound in Deep Tissue Pressure Injury: A Retrospective Analysis.

PURPOSE: The purpose of this study was to examine the effect of noncontact low-frequency ultrasound (NLFU) on deep tissue pressure injury (DTPI), both hospital-acquired and those present on admission (POA). DESIGN: Retrospective, descriptive study. SAMPLE AND SETTING: Medical records from 44 adult patients with a DTPI treated with NLFU were reviewed; 22 had a hospital-acquired DTPI (HADTPI) and 22 had DTPI POA. Their mean age was 71.3 ± 16.3 years (mean ± SD); 52% were male. The study setting was a 318-bed community hospital in the Mid-Atlantic region of the United States. METHODS: Data were collected from the medical records including demographic and relevant clinical characteristics, DTPI measurements, and DTPI evolution/resolution. Data were summarized and examined using descriptive statistics (eg, frequencies and percentages and means and standard deviations). Differences between groups were examined using paired t tests or the Mann-Whitney U test and the chi-square test as appropriate. In addition, the heel DTPI subgroup (N = 8) was examined separately due to the small sample size. RESULTS: All patients with HADTPI and DTPI POA treated with NLFU exhibited a statistically significant decrease in injury size from initiation to discontinuation of NLFU therapy (24.6 cm vs 14.4 cm, P = .02). No statistically significant difference in wound resolution was found between HADTPI versus DTPI POA (27% vs 18%, P = .47). Mean size of both HADTPI and DTPI POA decreased significantly from 15.9 to 13.4 cm (P = .045) by NLFU therapy. Wounds were classified as resolved at completion of treatment in 23% (10 out of 44) of all treated patients. Of all patients with the potential to be resolved (not discharged early or expired) 63% (10 out of 16) had wounds classified as resolved. CONCLUSION: Study findings suggest that NLFU is a viable and promising treatment option for both HADTPI and DTPI POA. Future studies are needed to confirm these results and to examine efficacy and feasibility of DTPI across care settings.

Las técnicas ecoguiadas, una herramienta muy útil también para enfermería / Ultrasound-guided techniques, also a very useful tool for nursing

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[Health issues and regulatory aspects of the use of ultrasound in physiotherapy]. / Problematiche sanitarie e aspetti normativi dell'utilizzo degli ultrasuoni in fisioterapia.

The use of ultrasounds in medicine requires, like all physical agents potentially harmful to human health, an accurate assessment of the risks to the health of patients. The nature and extent of these risks depend on exposure levels which in turn are differentiated according to the specific diagnostic or therapeutic applications. Intermediate exposure levels are associated to physiotherapic applications. To analyze specific issues relating to the effectiveness and safety of physiotherapic treatments, a review of the scientific literature and technical standards was carried out. At present, the actual effectiveness of ultrasound physiotherapy is still far from being clearly assessed: further clinical and experimental studies are needed in order to optimize therapies, determining the benefits and risks of treatments and deepening the understanding of the action mechanisms of the physical agent, even on the basis of a better characterization of those physical quantities mostly significant for biological effects. The examination of technical standards defining the security requirements of the equipment allowed the identification of some critical issues; on these bases some proposals are suggested for the improvement of quality and safety of treatments.

Ultrasound bio-effects and safety considerations.

The responsibility for safe ultrasound applications has been devolved to the user with the introduction of displayed safety indices on the scanner screen. It is therefore essential that the mechanisms of interaction of the ultrasound beam with the tissue being interrogated are properly understood and that the potential biological effects are determined.

Efficacy of conventional ultrasound therapy on myofascial pain syndrome: a placebo controlled study.

OBJECTIVES: Myofascial pain syndrome (MPS) is a complex pain syndrome characterized with trigger points (TP) in skeletal muscles. We aimed to assess the efficacy of ultrasound (US) therapy, which is one of the main devices used in physical medicine and rehabilitation, for the treatment of TP in MPS. METHODS: Fifty nine patients (49 females, 10 males) with active TP on the upper trapezius fibers were randomized into the treatment (n=30) and the control groups (n=29). The treatment group received conventional US therapy for 6 minutes, on 1.5 Watt/cm2 dose with 1 MHz frequency for 15 days whereas a placebo US therapy was administered to the control group. Prior to the treatment, immediately and 3 months later pain severity during rest and physical activity was assessed with visual analog scale (VAS), TP tenderness was measured with 0-5 scale, pressure pain threshold (PPT) was analyzed with algometer and the depression level was evaluated with Beck's depression questionnaire (BDP) by a clinician blinded to the groups. RESULTS: The mean age of the patients were 37.43±9.07 and 35.83±5.68 years, in the treatment and control groups, respectively. Compared to the pre-treatment values VAS, 0-5 scale and BDP scores decreased (p<0.01) along with an increase in PPT (p<0.01) in both groups at the follow-up visits. 0-5 scales and BDP scores were significantly lower and PPT was significantly higher in the treatment group, compared to the control group (p<0.001). CONCLUSION: Our results revealed that US treatment is effective on MPS.

Facts and misfits in ultrasound therapy: steps to improve your treatment outcomes.

Ultrasound has been used as a therapeutic agent for decades. Unfortunately many treatments are ineffective because the wrong treatment parameters are used. In this paper I present much of my work over the past 20 years with the goal of improving ultrasound use. Seven steps to optimal ultrasound use are presented. These include: treatment size area; movement speed of the transducer; and the "stretching window".

Theoretical study for safe and efficient energy transfer to deeply implanted devices using ultrasound.

The goal of this paper is to prove that a safe and efficient energy transfer is possible between an external transducer located on the patient's skin and a device deeply implanted in the abdomen. An ultrasound propagation model based on the Rayleigh-Sommerfeld diffraction integral is coupled with the data from the Visible Human Project to account for the geometry of the organs in the body. The model is able to predict the amount of acoustic power received by the device for different acoustic paths. The acoustic model is validated by comparison with measurements in water and in heterogeneous liquid phantoms. Care is taken to minimize adverse bioeffects-mainly temperature rise and cavitation in tissues. Simulations based on the bio-heat transfer equation are performed to check that thermal effects are indeed small.

Bio-effects and safety of low-intensity, low-frequency ultrasonic exposure.

Low-frequency (LF) ultrasound (20-100 kHz) has a diverse set of industrial and medical applications. In fact, high power industrial applications of ultrasound mainly occupy this frequency range. This range is also used for various therapeutic medical applications including sonophoresis (ultrasonic transdermal drug delivery), dentistry, eye surgery, body contouring, the breaking of kidney stones and eliminating blood clots. While emerging LF applications such as ultrasonic drug delivery continue to be developed and undergo translation for human use, significant gaps exist in the coverage of safety standards for this frequency range. Accordingly, the need to understand the biological effects of LF ultrasound is becoming more important. This paper presents a broad overview of bio-effects and safety of LF ultrasound as an aid to minimize and control the risk of these effects. Its particular focus is at low intensities where bio-effects are initially observed. To generate a clear perspective of hazards in LF exposure, the mechanisms of bio-effects and the main differences in action at low and high frequencies are investigated and a survey of harmful effects of LF ultrasound at low intensities is presented. Mechanical and thermal indices are widely used in high frequency diagnostic applications as a means of indicating safety of ultrasonic exposure. The direct application of these indices at low frequencies needs careful investigation. In this work, using numerical simulations based on the mathematical and physical rationale behind the indices at high frequencies, it is observed that while thermal index (TI) can be used directly in the LF range, mechanical index (MI) seems to become less reliable at lower frequencies. Accordingly, an improved formulation for the MI is proposed for frequencies below 500 kHz.

Exploiting thermochromic materials for the rapid quality assurance of physiotherapy ultrasound treatment heads.

Significant nonuniformities in the acoustic intensity distribution generated by physiotherapy ultrasound treatment heads are not uncommon, potentially leading to significant localised temperature rises and tissue damage. An acoustic absorber tile containing a thermochromic pigment has been developed to provide rapid quality assurance of physiotherapy ultrasound treatment heads by virtue of a thermochromic colour change, indicating the time-averaged intensity distributions generated by these devices. As a bench-top device, the use of the tile is designed to mimic the nature of the physiotherapeutic application, requiring minimal training. Two designs where thermochromic pigments are added to the various polymeric layers of the tile are presented. Testing has been conducted with two physiotherapy treatment heads of differing performance, one of them notably exhibiting a strong "hot-spot" in localised acoustic time-averaged intensity. Findings show good qualitative agreement with classical hydrophone scans. Techniques are explored for the correction of nonlinearities in the thermochromic relationship, to enhance the accuracy of quantitative assessment.

Improvised source of water coolant for ultrasonic scaler: an appropriate technology in underserved communities.

Traditionally dental plaque, calculus and stains have been removed by scaling and polishing manually with hand instruments such as curettes, chisels, hoes and scalers. However, ultrasonic scaling is becoming the preferred method of initial periodontal treatment and maintenance, due to improved patient and operator comfort. Ultrasonic scaling can be performed effectively using pipe-borne water as coolant. However, such a water supply is unavailable in many rural dental clinics, especially in underserved communities in Nigeria. This article reports on an improvised source of water coolant, designed and fabricated to make modern, easy and effective plaque control available to people in communities where there is no pipe-borne water. The device will improve operator efficiency in tooth cleaning and patient compliance with treatment. Due to its simple design but effective function, the device is ideal for use in Nigeria's primary healthcare delivery program, offering enhanced preventive and curative services to remote, rural and semi-urban populations. In doing so oral health can be improved with a reduction in the incidence of oral diseases.

Minimizing the thermal losses from perfusion during focused ultrasound exposures with flowing microbubbles.

This paper demonstrated the use of flowing microbubbles (MBs) to minimize thermal losses from perfusion during focused ultrasound exposures due to acoustic cavitation. Temperature and cavitation were simultaneously investigated as MBs flowing through a wall-less flow phantom with varying flow velocities (2-55 cm/s) and concentrations (0%-0.1%) when exposed at different acoustic power levels (5-120 W). The peak temperature at the end of ultrasonic exposures in the flow and in the outer of the vessel as well as the cavitation were higher than those pure controls measured at the same exposure parameters and flow velocities but without MBs. All the peak temperatures initially increased with increasing flow velocities of MBs, followed by a decrease of the peak temperatures with increasing flow velocities when the velocity was higher than the inflection velocity. Meanwhile, cavitation showed a trend of increases with increasing flow velocity. The inflection velocity and cavitation increased with increasing acoustic power and MBs concentration. Thermal lesion appeared around the vessel as MBs flow through the vessel, at which lesion was not observed originally without MBs. These results suggested that this may provide an effective way to minimize thermal losses from perfusion during focused ultrasound exposures.