Linear Array Transducer Research Articles

3-D Contrast-Enhanced Fusion Ultrasound for Accurate Volume Assessment of Vessel Lumen and Plaque in Carotid Artery Disease as Compared With Computed Tomography Angiography

ObjectiveThree-dimensional contrast-enhanced fusion ultrasound (3D-CEFUS) of atherosclerotic carotid arteries provides spatial visualisation of the vessel lumen, creating a lumenography. As in 3D computed tomography angiography (3D-CTA), 3D-CEFUS outlines the contrast-filled lumen. Plaque and vessel contours are distinguished in 3D-CEFUS, allowing plaque volume quantification as a valid estimate of carotid plaque burden. 3D-CEFUS is unproven in inter-modality studies, vindicating the assessment of 3D-CEFUS applicability and comparing 3D-CEFUS and 3D-CTA lumenography as a proof-of-concept study. MethodsUsing an ultrasound system with magnetic tracking, a linear array transducer, and SonoVue contrast agent generated 3D-CEFUS acquisitions by spatial stitching of serial 2D images. From 3D-CEFUS and 3D-CTA imaging, the atherosclerotic carotid arteries were reconstructed with lumenography in an offline software programme for lumen and plaque volume quantification. Bland-Altman analysis was used for inter-image-modality agreement. ResultsThe study included 39 carotid arteries. Mean lumen and plaque volume in 3D-CEFUS were 0.63 cm3 (SD 0.26) and 0.62 cm3 (SD 0.26), respectively. Lumen volume differences between 3D-CEFUS and 3D-CTA were non-significant, with mean difference of 0.01 cm3 (SD 0.02, p = .26) and limits of agreement range (LoA-range) of ±0.11 cm3. Mean plaque volume difference was -0.12 cm3 (SD 0.19, p = .006) with LoA-range of ±0.39 cm3. ConclusionStrong agreement in lumenography between 3D-CEFUS and 3D-CTA was found. The inter-image-modality difference in plaque volumes was substantial due to challenging vessel wall definition in 3D-CTA. 3D-CEFUS is viable in quantifying carotid plaque volume burden and can potentially monitor plaque development over time.

Underestimation of Flow Velocity in 2-D Super-Resolution Ultrasound Imaging.

Velocity estimation in ultrasound imaging is a technique to measure the speed and direction of blood flow. The flow velocity in small blood vessels, i.e., arterioles, venules, and capillaries, can be estimated using super-resolution ultrasound imaging (SRUS). However, the vessel width in SRUS is relatively small compared with the full-width-half-maximum of the ultrasound beam in the elevation direction (FWHMy), which directly impacts the velocity estimation. By taking into consideration the small vessel widths in SRUS, it is hypothesized that the velocity is underestimated in 2-D super-resolution ultrasound imaging when the vessel diameter is smaller than the FWHMy. A theoretical model is introduced to show that the velocity of a 3-D parabolic velocity profile is underestimated by up to 33% in 2-D SRUS, if the width of the vessel is smaller than the FWHMy. This model was tested using Field II simulations and 3-D printed micro-flow hydrogel phantom measurements. A Verasonics Vantage 256™ scanner and a GE L8-18i-D linear array transducer with FWHMy of approximately 770 μm at the elevation focus were used in the simulations and measurements. Simulations of different parabolic velocity profiles showed that the velocity underestimation was 36.8%±1.5% (mean±standard deviation). The measurements showed that the velocity was underestimated by 30%±6.9%. Moreover, the results of vessel diameters, ranging from 0.125×FWHMy to 3×FWHMy, indicate that velocities are estimated according to the theoretical model. The theoretical model can, therefore, be used for the compensation of velocity estimates under these circumstances.

Comparison of pre-mortem 2D-3D ultrasound examination to post-mortem micro-CT of carotid arteries - first experiences.

<p>A prerequisite for the treatment of carotid atherosclerosis is the accurate measurement of the stenosis, that is most commonly evaluated by duplex ultrasonography. In this study, we aimed to verify the reliability of 2D and 3D ultrasonography, comparing the data to results of post-mortem micro-CT examination.</p>. <p>Neurological patients with any life-threatening, presumably fatal neurological disease were enrolled. Ultrasound examinations were performed with a Philips Epiq 5G machine, using a VL13-5 broadband linear volume array transducer. Plaque length, diameter and vessel area reduction (stenosis) were calculated using the 2D images. Finally, the stenosis was reassessed using automatized, 3D application as well. After the death of the patient, autopsy was performed, during which the previously examined carotid artery was removed. The samples were examined with micro-CT. Similar to the ultrasound examination, plaque length, diameter and vessel area reduction (stenosis) were determined.</p>. <p>Ten vessels of seven patients were eligible for complex comparison. Plaque diameter and length measured by CT did not correlate with the ultrasound data. CT-measured axial plaque and vessel areas showed no correlation with ultrasound results either. While determining the strength of correlation between stenoses measured by the different modalities, significant correlation was found between the results measured by ultrasound (2D) and CT (Pearson r: 0.902, P&lt;0.001).</p>. <p>Three-dimensional ultrasound analysis is a spectacular method for examining carotid plaques, as it can assist in a more detailed evaluation of the plaque morphology and composition, thereby identifying plaques with a particularly high risk of stroke. Micro-CT is an excellent tool for the exact determination of calcified plaque areas, but ultrasound images are not suitable yet for such a precise examination due to acoustic shadowing and artifacts.</p>.

Three-Dimensional Magneto-Acousto-Electrical Computed Tomography (3D MAE-CT): A Preliminary Study Using Ultrasound Linear Array Transducer.

Magneto-acousto-electrical tomography (MAET) is a hybrid imaging method that combines the high spatial resolution of ultrasonography with the high contrast of electrical impedance tomography (EIT). While most previous studies on MAET have focused on two-dimensional imaging, our recent research proposed a novel three-dimensional (3D) MAET method using B-mode and translational scanning. This method has been the first to reconstruct a 3D volume image of conductivity interfaces. However, this method has its limitations in mapping irregular shapes of conductivity. To address this challenge, we propose a 3D magneto-acousto-electrical computed tomography (3D MAE-CT) method utilizing an ultrasound linear array transducer in this work. Both phantom and in vitro experiments were conducted to validate our proposed method. The results from the phantom experiments demonstrate that our method can map the 3D volume conductivity with high spatial resolution. The oblique angles extracted from the 3D image closely match practical value, with the relative error ranging between -2.80% and 4.07%. Furthermore, the in vitro experiment successfully obtained a 3D image of a chicken heart, marking the first MAET 3D conductivity image of a tissue sample to date.

Venous Pseudoaneurysms: Sonographic Presentation, Correlation with Other Diagnostic Imaging Techniques, and Supported by the Literature

Objective: The objective of this study is to demonstrate the sonographic and computed tomographic features of venous pseudoaneurysms and show the difference between true and false venous aneurysms and arterial pseudoaneurysms. Likewise, it was important to provide a historical context based on a literature review of vascular aneurysms and pseudoaneurysms, emphasizing venous pseudoaneurysms. Materials and Methods: Clinical cases are presented for context, and the vascular examinations were performed utilizing a General Electric (GE) Logiq Fortis or Logiq S8 scanners with a broad-band linear-array transducer (L2-9). Computed tomography (CT) with contrast was performed on a GE Revolution Maxima 64-slice CT scanner with 100 mL Omnipaque-350 as a contrast agent. The three-dimensional (3D) axial, sagittal, and coronal reconstructions were made with the Philips IntelliSpace software. Levels of evidence are provided based on a literature search of relevant publications using the National Library of Medicine, PubMed, and Google Books. Results: Different types of venous pseudoaneurysms, venous aneurysms, and arterial pseudoaneurysm diagnosed by duplex sonography and CT were presented. An extensive historical and literature review was conducted based on publications from the 18th to 21st centuries. Conclusion: Venous pseudoaneurysms are uncommon. Most of them are iatrogenic and are usually found as a complication of repetitive venipuncture in patients receiving hemodialysis with arteriovenous fistulas. In rare cases, venous pseudoaneurysms occur spontaneously.

The development of a systematic ultrasound protocol facilitates the visualization of foreign bodies within the canine distal limb.

Ultrasonography is an excellent investigative tool that can assist with the diagnosis of soft tissue conditions. In human medicine, ultrasonography is a fundamental diagnostic tool for the investigation of suspected vegetal foreign bodies (VFB), with protocol-based ultrasonography providing increased accuracy compared to lesion-focused examinations. Protocol-based ultrasonography is an emerging tool within the veterinary field, however, compared to human medicine is not routinely employed. The objective of this study was to develop a systematic ultrasound protocol to examine the distal limb for the visualization of vegetal foreign bodies (SUEDVEG). A 12 MHz linear and an 18 MHz high-frequency small-footprint linear array transducer was used on cadaver forelimbs (n = 6) and hindlimbs (n = 6) with images obtained from three common foreign body locations within the distal limb; 1; the interdigital webbing, 2; the palmar/plantar aspect of the phalanges and metacarpus and 3; the dorsal region of the phalanges and metacarpus. From these images, a 13-step systematic musculoskeletal protocol was developed and utilized on eight clinical cases or 10 limbs that had signs typical of distal limb VFB to preliminarily validate the proposed method. Vegetal foreign bodies were successfully identified and retrieved in seven (n = 8) clinical cases with method steps 9 and 11 (orthogonal views) identifying the majority of VFBs. The described ultrasound method appears highly useful for visualizing soft tissue locations of the canine distal limb known for tracking foreign bodies. Further studies are required to validate the described systematic examination method as the preferred clinical protocol over currently used lesion-focused exploration techniques.

The role of preoperative ultrasound in the management of peripheral nerve injuries

BackgroundPeripheral nerve injury refers to any damage or trauma to the nerves located outside the central nervous system. Ultrasonography is a reliable, cheap, and minimally invasive method in clinical practice to give physicians useful information about nerve injury. Objectivesto assess the power of ultrasound in determining the presence, localization, and extent of neural damage in patients with clinical evidence of peripheral nerve lesions before surgery. MethodsThis cross-sectional study was conducted on 78 patients (56 females and 22 males, aged from 9 to 52 years) who had different pathologies including entrapment, tumoral, post-traumatic, and post-surgical nerve injuries at the Neurosurgery and Physical Medicine, Rheumatology, and Rehabilitation Departments, Tanta University Hospitals. All studied patients had preoperative evaluation; neurological examination, electrodiagnostic studies, and sonographic examinations with linear array transducers (frequencies ranging from 7.5 to 16 MHz). ResultsThe most common pathological condition was entrapment neuropathy (39 patients) (50%). Ultrasound complemented the electrodiagnostic studies by determining the site of entrapment manifested by increased mean maximum cross-sectional area of the nerve proximal to the site of entrapment and nerve hypoechogenicity. In post-traumatic and iatrogenic neuropathies (35 patients) (44.9%), the ultrasound finding revealed neuroma in continuity in nine cases (11.5%), complete neurotmesis with stump neuroma in eighteen patients (23.1%), and eight cases (10.3%) showed perineural adhesion. In all cases, the nerve was hypoechoic at the site of injury. The presence of hyperechoic fibrous tissue could indicate perineural adhesion and the necessity for neurolysis. This study also included three (3.8%) cases had schwannoma, and one case (1.3%) had neurofibroma. Ultrasound was used to confirm the diagnosis by determining the tumor's size and vascular supply. ConclusionsUltrasonography is a diagnostic and surgical planning tool that is becoming more and more useful for the management of peripheral nerve injuries. Its high resolution and real-time capability provide safe and cost-effective scans that aid in determining the extent of injuries. For patients with peripheral nerve injuries, ultrasound is advised to be added to the routine clinical and neurophysiological evaluation. It is also advised to use ultrasound as a first-line imaging modality for tumors thought to be of nerve origin.

The development of a flexible linear array transducer with high bandwidth based on piezoelectric composite

The development of a flexible linear array transducer with high bandwidth based on piezoelectric composite

Variational mode decomposition based self-adaptive denoising imaging method for ultrasonic array testing of coarse-grained titanium alloys processed by additive manufacturing

The coarse columnar grain structure in titanium alloys processed by additive manufacturing leads to strong grain noise in ultrasonic testing, which affects the accurate detection and quantification of its defects. In this paper, a self-adaptive denoising imaging method for ultrasonic array testing is proposed based on variational mode decomposition (VMD). The proposed method uses VMD to decompose complex ultrasonic signals in full matrix capture (FMC) data collected by a linear ultrasonic array transducer. According to the particle swarm optimization (PSO) method, VMD parameters for FMC methods of the total focusing method (TFM), the plane wave imaging (PWI), and the Hadamard spatial encoding are self-adaptively determined. The evaluation parameters are set to select the intrinsic mode function components by VMD to complete the denoising reconstruction and imaging of FMC data. An additive-manufactured titanium alloy specimen was used to verify the improvement of defect detection capability by PSO-VMD denoising method. For a defect at large thickness in the specimen, compared with the conventional TFM and PWI methods, VMD denoising method based on the Hadamard spatial encoding can improve the signal-to-noise ratio by 7.7 dB and 9.0 dB, and reduce the quantitative error by 74 % and 68 %.

Signal domain adaptation network for limited-view optoacoustic tomography

Optoacoustic (OA) imaging is based on optical excitation of biological tissues with nanosecond-duration laser pulses and detection of ultrasound (US) waves generated by thermoelastic expansion following light absorption. The image quality and fidelity of OA images critically depend on the extent of tomographic coverage provided by the US detector arrays. However, full tomographic coverage is not always possible due to experimental constraints. One major challenge concerns an efficient integration between OA and pulse-echo US measurements using the same transducer array. A common approach toward the hybridization consists in using standard linear transducer arrays, which readily results in arc-type artifacts and distorted shapes in OA images due to the limited angular coverage. Deep learning methods have been proposed to mitigate limited-view artifacts in OA reconstructions by mapping artifactual to artifact-free (ground truth) images. However, acquisition of ground truth data with full angular coverage is not always possible, particularly when using handheld probes in a clinical setting. Deep learning methods operating in the image domain are then commonly based on networks trained on simulated data. This approach is yet incapable of transferring the learned features between two domains, which results in poor performance on experimental data. Here, we propose a signal domain adaptation network (SDAN) consisting of i) a domain adaptation network to reduce the domain gap between simulated and experimental signals and ii) a sides prediction network to complement the missing signals in limited-view OA datasets acquired from a human forearm by means of a handheld linear transducer array. The proposed method showed improved performance in reducing limited-view artifacts without the need for ground truth signals from full tomographic acquisitions.

Three-dimensional ultrasound matrix imaging

Matrix imaging paves the way towards a next revolution in wave physics. Based on the response matrix recorded between a set of sensors, it enables an optimized compensation of aberration phenomena and multiple scattering events that usually drastically hinder the focusing process in heterogeneous media. Although it gave rise to spectacular results in optical microscopy or seismic imaging, the success of matrix imaging has been so far relatively limited with ultrasonic waves because wave control is generally only performed with a linear array of transducers. In this paper, we extend ultrasound matrix imaging to a 3D geometry. Switching from a 1D to a 2D probe enables a much sharper estimation of the transmission matrix that links each transducer and each medium voxel. Here, we first present an experimental proof of concept on a tissue-mimicking phantom through ex-vivo tissues and then, show the potential of 3D matrix imaging for transcranial applications.

Ultrasound imaging of the testes in children and adolescents

Ultrasound, the imaging method of choice to evaluate abnormalities of the testes and the scrotum, provides accurate anatomic details and allows the assessment of perfusion using color Doppler and power Doppler. Ultrasound represents arapid and reliable procedure which in most cases leads to aconclusive diagnosis. The three most common conditions in the clinical picture of acute scrotum are testicular torsion, torsion of the testicular appendages and inflammatory changes of the testis and the epididymis (epididymo-orchitis). Especially in the case of testicular torsion, rapid diagnosis is essential since time is an important factor to initiate organ-preserving therapy. High-frequency linear array transducer (at least 10 MHz), which allows detection of slow flow rates, is recommended.

Sonographic evaluation of common carotid artery intima-media thickness in adults with coexisting type two (2) diabetes and hypertension: A case-controlled study

Diabetes mellitus (DM) and hypertension (HTN) are the two leading risk factors for atherosclerosis. Carotid intima-media thickness (CIMT) is considered a reliable surrogate measure for detecting subclinical atherosclerosis including its progression and regression. The study aim at evaluating the intima-media thickness of the common carotid artery in adults with coexisting diabetes mellitus and hypertension (DM+HTN) and compare with healthy controls.. A prospective case control study involving 115 adult subjects with coexisting DM+HTN and 144 healthy adult controls was carried out. Common carotid intima-media thickness (CCIMT) was measured at point approximately 1 cm distal to the right and left carotid bulb using the 7-12 MHz, multi-frequency linear array transducer of high resolution, touch Venue 50 ultrasound machine equipped with electronic callipers. The overall mean CCIMT was 1.13±0.40 mm and 0.82±0.23 mm for subjects with coexisting DM and HTN; and healthy controls, respectively. There was a statistically significant difference in CIMT of subjects with DM+HTN compared to healthy controls (p=0.000 each for both males and females, respectively). There were positive correlations between CCIMT and age in subjects with DM+HTN (r=0.260 and r=0.424 for males and females respectively); with healthy controls (r=0.619 and 0.626 for males and females, respectively). There was a statistically significant difference in CCIMT between subjects with DM+HTN and healthy controls. This implies that the increase in CCIMT is associated with both DM and HTN. In addition, age has a significant positive relationship with CCIMT in both subjects with DM+HTN and healthy controls.

Diagnostic efficacy of quantitative ultrasonography for anterior disc displacement of the temporomandibular joint.

Ultrasonography has been applied as an alternative method in the assessment of temporomandibular joint (TMJ) pathology including anterior disc displacement (ADD). However, a concrete screening or diagnostic method which is feasible in clinical practice has not yet been established. The study aimed to establish a quantitative ultrasonographic method and determine its diagnostic efficacy for ADD of the TMJ. A total of 75 joints were allocated to either the normal disc position (NDP) group or the ADD group using magnetic resonance imaging (MRI) as the reference standard. Longitudinal scans of the lateral articular compartment were obtained by a 14-MHz L-shaped linear array transducer. The width of the lateral joint space (LJS), the upper lateral joint space (ULJS), and the lower lateral joint space (LLJS), as well as the position of the lateral articular disc edge (ADE), were investigated by stepwise logistic regression analysis to identify significant indicators of ADD and to build a diagnostic model. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were computed at the optimal cut-off value. MRI detected 25 joints in the NDP group and 50 joints in the ADD group. Correlation analysis indicated that all 4 variables were associated with ADD. With the best performance of the area under the receiver operating characteristic (ROC) curve (AUC) of 0.939, LJS and ULJS were identified as predictors of ADD and subsequently adopted to build a diagnostic model by stepwise logistic regression. The optimal cut-off value of the 2-variable regression model for diagnosing ADD was 0.800, with a sensitivity of 82%, specificity of 96%, PPV of 97.6%, NPV of 72.7%, and an accuracy of 86.7%. The quantitative ultrasonographic diagnostic method showed promising diagnostic efficacy. It has the potential to be used for ADD screening in future clinical practice.

Flexible Ultrasound Transducer With Embedded Optical Shape Sensing Fiber for Biomedical Imaging Applications.

Flexible ultrasound transducers (FUTs), capable of conforming to irregular surfaces, have become a research hotspot in the field of medical imaging. With these transducers, high-quality ultrasound images can be obtained only if strict design criteria are fulfilled. Moreover, the relative positions of array elements must be determined, which are important for ultrasound beamforming and image reconstruction. These two major characteristics present great challenges to the design and fabrication of FUTs compared to that for traditional rigid probes. In this study, an optical shape-sensing fiber was embedded into a 128-element flexible linear array transducer to acquire the real-time relative positions of array elements to produce high-quality ultrasound images. Minimum concave and convex bend diameters of approximately 20 and 25 mm, respectively, were achieved. The transducer was flexed 2000 times, and yet no obvious damage was observed. Stable electrical and acoustic responses confirmed its mechanical integrity. The developed FUT exhibited an average center frequency of 6.35 MHz, and average -6-dB bandwidth of 69.2%. The array profile and element positions measured by the optic shape-sensing system were instantly transferred to the imaging system. Phantom experiments for both spatial resolution and contrast-to-noise ratio proved that FUTs can maintain satisfactory imaging capability despite bending to sophisticated geometries. Finally, color Doppler images and Doppler spectra of the peripheral arteries of healthy volunteers were obtained in real time.

Serum Chromium is Inversely Correlated with the Carotid Intima– Media Thickness in Type 2 Diabetic Subjects

Objective: The aim of this study was to determine and correlate the serum chromium in Carotid intima - media thickness (CIMT) in type 2 Diabetes Mellitus (T2DM) subjects.&#x0D; Materials and Methods: The present case – control study included 40 healthy controls and 45 T2DM subjects that were selected through non-probability (purposive) sampling by prior inclusion and exclusion criteria. Serum chromium (Cr) was detected and measured on inductively coupled “Plasma Optical Emission Spectrophotometer” (ICP- OES)- Carotid artery was examined with a 7.5-MHz linear-array transducer (Siemens Acuson x300) sonography. Data was analyzed by Student’s t test and Chi square test in the SPSS 22.0 (USA). Linear regression model was used for predicting carotid intima media thickness. Level of confidence interval of statistical significance was 95% (P≤ 0.05).&#x0D; Results: Serum Cr in controls and cases was noted 0.873 (± 0.162) and 0.281 (± 0.240) µg/ml (P= 0.001). Serum Cr proved negative correlation with random blood sugar (r= -0.145, P= 0.185), HbA1c (r= -0.145, P= 0.0001) and CIMT (r= -0.730, P= 0.0001). Multiple regression analysis model showed significant association of serum Cr (r= -0.730, P&lt; 0.0001) and HbA1c (r= 0.754, P&lt; 0.0001) with the CIMT.&#x0D; Conclusion: The present study reported serum Cr was inversely correlated with the carotid intima - media thickness that is a marker of atherosclerosis. Cr supplements may be advised to diabetics in clinical management.

Sonographic assessment of the common carotid artery luminal diameter in adults with co-existing diabetes mellitus and hypertension

Background: Diabetes mellitus (DM) and hypertension (HTN) are known to cause major in changes in arterial morphology and function, (remodelling) including alterations in carotid intima media thickness (CIMT), carotid artery luminal diameter (CALD), and arterial compliance and blood flow velocity. However, there is a paucity of data evaluating common carotid luminal diameter (CCALD) in an adult with both DM and HTN (DM+HTN) in the study locality. Objective: This study is therefore aimed at evaluating the CCALD in adults with DM+HTN. Methodology: One hundred and fifteen (115) adult subjects with co-existing DM+HTN and one hundred and fourty four (144) healthy controls participated in the study. Their ages ranged from 18 to 80 years. The common carotid artery luminal diameter (CCALD) at the diastolic phase of the cardiac cycles was scanned and measured using a venue 50 ultrasound scanners with electronic calipers and high frequency linear array transducer. Result: The overall mean CCALD was 6.43±0.87 mm and 5.88±0.77 mm for subjects with DM+HTN and healthy controls, respectively. The mean CCALD value was significantly higher in subjects DM+HTN compared to the healthy controls (0.000). The mean CCALD correlated positively with age in males with DM+HTN hypertensive females, while no significant correlations were observed among healthy controls. Males had significantly higher mean CCALD value when compared to their female counterparts in both subjects with DM+HTN and healthy controls. Conclusion: In this study, the mean CCALD value in subjects with DM+HTN is significantly higher compared to those of healthy controls.

The utility of a portable muscle ultrasound in the assessment of muscle alterations in children with acute lymphoblastic leukaemia.

During treatment for acute lymphoblastic leukaemia (ALL), children are prone to musculoskeletal deterioration. However, non-invasive tools to measure muscle mass and intramuscular alterations are limited. In this study we explored the feasibility of muscle ultrasound in children with ALL. Additionally, we analysed whether automated ultrasound outcomes of muscle size and intramuscular fat infiltration (IMAT) were associated with appendicular skeletal muscle mass (ASMM), muscle strength and physical performance. Children with ALL, aged 3-18years were included during maintenance therapy. Bilateral images of the rectus femoris muscle were captured using a portable linear array transducer connected to a tablet. Subsequently, an automated image annotation software (MuscleSound) was used to estimate cross-sectional area, muscle thickness and IMAT. Feasibility was assessed using acceptance (percentage of children approached who were enrolled), practicality (percentage of children that completed the ultrasound measurement after enrolment) and implementation (percentage of children that had sufficient imaging to be processed and analysed by the software). Assessments of ASMM by bioimpedance analysis, muscle strength using handheld dynamometry and timed physical performance tests were administered at the same visit. Multivariable linear models were estimated to study the associations between muscle ultrasound outcomes and ASMM, strength and physical performance, adjusted for sex, age, body mass index and ALL treatment week. Muscle ultrasound was performed in 60 out of 73 invited patients (76.9%), of which 37 were boys (61.7%), and median age was 6.1years (range: 3-18.8years). The acceptance was 98.7%, practicality 77.9% and implementation was 100%. Patients who refused the examination (n=13) were younger (median: 3.6, range: 3-11.2years) compared with the 60 examined children (P=0.0009). In multivariable models, cross-sectional area was associated with ASMM (β=0.49 Z-score, 95% confidence interval [CI]:0.3,2.4), knee-extension strength (β=16.9 Newton [N], 95% CI: 4.8, 28.9), walking performance (β=-0.46s, 95% CI: -0.75, -0.18) and rising from the floor (β=-1.07s, 95% CI: -1.71, -0.42). Muscle thickness was associated with ASMM (β=0.14 Z-score, 95% CI: 0.04, 0.24), knee-extension strength (β=4.73N, 95% CI: 0.99, 8.47), walking performance (β=-0.13s, 95% CI: -0.22, -0.04) and rising from the floor (β=-0.28s, 95% CI: -0.48, -0.08). IMAT was associated with knee-extension strength (β=-6.84N, 95% CI: -12.26, -1.41), walking performance (β=0.2s, 95% CI: 0.08, 0.32) and rising from the floor (β=0.54s, 95% CI: 0.27, 0.8). None of the muscle ultrasound outcomes was associated with handgrip strength. Portable muscle ultrasound appears a feasible and useful tool to measure muscle size and intramuscular alterations in children with ALL. Validation studies using magnetic resonance imaging (gold standard) are necessary to confirm accuracy in paediatric populations.

Assessment of common extensor tendon vascularization using superb microvascular imaging: a potential tool in the evaluation of extracorporeal shock wave therapy and therapeutic ultrasound effectiveness in lateral epicondylitis.

Lateral epicondylitis, also known as tennis elbow, is the most common elbow pain in the adult age group. To evaluate common extensor tendon (CET) vascularity with superb microvascular imaging (SMI) before and after extracorporeal shock wave therapy (ESWT) and ultrasound (US) treatment in patients with lateral epycondylitis and to compare the effects of two different treatments on tendon vascularity. Patients with lateral epycondylitis were divided into two groups; 30 patients were treated with ESWT (group 1) and 30 patients were treated with therapeutic US (group 2). We performed a high-frequency (14-MHz) linear array transducer to evaluate tendon anatomy and vascularity before and after treatment in both groups. The decrease in Patient-Rated Tennis Elbow Evaluation (PRTEE) score after treatment was statistically significant compared to pre-treatment for both groups (P < 0.001). Likewise, the decrease in visual analog scale (VAS) score after treatment was statistically significant compared to pre-treatment for both groups (P < 0.001). A significant difference was found between the CET SMI values of group 1 and group 2 after treatment, according to the chi-square test (P < 0.001). In the post-treatment VAS and PRTEE comparison of both groups, the score reduction in group 1 was higher than in group 2, and this decrease was statistically significant (P < 0.001). We can evaluate CET vascularization with the SMI method as a new potential diagnostic tool in comparing the effectiveness of different treatments in cases of lateral epicondylitis.

Full Waveform Inversion for NDT using ultrasonic linear arrays

Ultrasonic (UT) imaging is a widespread technique for nondestructive testing (NDT). The state-of-the-art UT image reconstruction algorithms are based on delay-and-sum (DAS) operations, which assume constant acoustic velocity across the tested objects and also neglects nonlinear effects such as diffractions and multiple reflections. These assumptions limit the reconstruction capabilities of DAS-based algorithms, especially for complex objects composed by several materials. In seismology, Full Waveform Inversion (FWI) methods have been used to obtain subsurface properties based on scattered and transmitted sound waves - which is a very similar problem to ultrasonic imaging in NDT - using the full wave information, showing promising results. In this paper, we present the application of FWI in NDT using simulated data representing acquisitions with a common linear array transducer. We review the theoretical formulation of FWI and discuss some difficulties that arise when it is applied to NDT. Image reconstruction is performed using both a state-of-the-art DAS algorithm, namely the Total Focusing Method, and FWI. The implementation targets a GPU platform, using the CUDA API. This leverages the highly parallelizable nature of the simulations and the FWI algorithm. The obtained results show that FWI can show more internal structures than TFM, with less information about the specimen. To foster further development, all source codes are provided.