Ultrasound-based System Research Articles

Effectiveness evaluation of the Thyroid Imaging Report and Data System proposed by American Radiological Society (2017) (ACR-TIRADS) for differential diagnosis in thyroid nodules

Objective To evaluate the effect of the Thyroid Imaging Report and Data System proposed by American Radiological Society (ACR-TIRADS) for differential diagnosis in thyroid nodules, and compare ACR-TIRADS to the TIRADS proposed by Kwak et al.(K-TIRADS) and the ultrasound-based risk stratification system evaluated by American Thyroid Association (ATA-Risk Stratification). Methods The clinical data of 1 760 patients with 1 912 thyroid nodules from 8 hospitals in Jiangsu province were retrospectively analysed. All of them were categorized based on ultrasound-based risk stratification systems. The ROC curve was established to assess and compare the diagnostic value of the systems. Results The area under the ROC curve (AUC) of ACR-TIRADS was 0.830, with high sensitivity and negative predictive value (86.9% and 87.5%, respectively), and relatively low specificity and positive predictive value (64.1% and 62.9%, respectively). The sensitivity and specificity of K-TIRADS were up to 84.9% and 76.1%, respectively. The AUC of ATA-Risk Stratification was 0.852, with relatively high specificity (83.4%), and low sensitivity (79.4%). There were significant differences in the AUC among the three ultrasound-based risk stratification systems, of which K-TIRADS was the highest (P<0.001). There was no significant difference in sensitivity of ACR-TIRADS and K-TIRADS (P=0.137), but significantly higher than that of ATA-Risk Stratification (P<0.001). There were significant differences in the specificity among the three systems, of which ATA-Risk Stratification was the highest (P<0.001). In addition, there were 109 nodules (5.7%) couldn′t be classified based on ATA-Risk Stratification, with high malignancy rate of 31.2%. Conclusions The diagnostic efficiency of ACR-TIRADS is good, but lower than K-TIRADS and ATA-Risk Stratification. ACR-TIRADS has the highest sensitivity, and ATA-Risk Stratification has the highest specificity, while the overall diagnostic efficiency of K-TIRADS is the best. Key words: Ultrasonography; Thyroid nodule; Thyroid imaging reporting and data system; Ultrasound-based risk stratification; Differential diagnosis

Comparison of joint status in children with haemophilia A using ultrasound and physical examination

Purpose: This study aimed to compare assessments of joint status conducted by a physiotherapist using a clinical scoring system, Haemophilia Joint Health Score (HJHS 2.1), and an ultrasound-based scoring system, Haemophilia Early Arthropathy Detection with UltraSound (HEAD-US), for detecting early signs of haemophilic arthropathy.Materials and methods: The study group comprised 32 patients aged 6–17 years with a moderate or severe bleeding disorder, haemophilia A. The elbow, ankle and knee joints were evaluated using HJHS 2.1 and HEAD-US.Results: There was a strong correlation between total scores of the clinical scoring system and the ultrasound scoring system (rS =0.66, p < .01) for elbows and knees (rS = 0.57, p < .01 and rS = 0.76, p < .01, respectively). The correlation for ankles was substantially weaker (rS = 0.36, p = .04). The clinical scores correlated also with annual bleeding rate.Conclusions: The total and individual joint scores, especially for knees and elbows, using “Haemophilia Early Arthropathy Detection with UltraSound” correlated well with “Haemophilia Joint Health Score”. The clinical score, also measuring function, correlated better with bleeding rate. The relevance of HEAD-US as a prognostic tool is still unclear.

DELIVERABILITY AND SAFETY OF A NOVEL NON-INVASIVE, ULTRASOUND-BASED RENAL NERVE ABLATION SYSTEM IN A LARGE PRECLINICAL MODEL VIA HISTOPATHOLOGICAL EVALUATION

Background: Although controversial, RDN has been proposed as an alternative therapy for resistant hypertensive patients. We aim to evaluate the acute and subchronic safety and deliverability of a novel extracorporeal, ultrasound-based RDN system in a large animal model. Methods: 7 swine were

Non-invasive, non-ionizing fatty liver assessment by means of a new ultrasound-based imaging system: The Steatometer

Non-invasive, non-ionizing fatty liver assessment by means of a new ultrasound-based imaging system: The Steatometer

Tumor characterization and treatment monitoring of postsurgical human breast specimens using harmonic motion imaging (HMI).

BackgroundHigh-intensity focused ultrasound (HIFU) is a noninvasive technique used in the treatment of early-stage breast cancer and benign tumors. To facilitate its translation to the clinic, there is a need for a simple, cost-effective device that can reliably monitor HIFU treatment. We have developed harmonic motion imaging (HMI), which can be used seamlessly in conjunction with HIFU for tumor ablation monitoring, namely harmonic motion imaging for focused ultrasound (HMIFU). The overall objective of this study was to develop an all ultrasound-based system for real-time imaging and ablation monitoring in the human breast in vivo.MethodsHMI was performed in 36 specimens (19 normal, 15 invasive ductal carcinomas, and 2 fibroadenomas) immediately after surgical removal. The specimens were securely embedded in a tissue-mimicking agar gel matrix and submerged in degassed phosphate-buffered saline to mimic in vivo environment. The HMI setup consisted of a HIFU transducer confocally aligned with an imaging transducer to induce an oscillatory radiation force and estimate the resulting displacement.Results3D HMI displacement maps were reconstructed to represent the relative tissue stiffness in 3D. The average peak-to-peak displacement was found to be significantly different (p = 0.003) between normal breast tissue and invasive ductal carcinoma. There were also significant differences before and after HMIFU ablation in both the normal (53.84 % decrease) and invasive ductal carcinoma (44.69 % decrease) specimens.ConclusionsHMI can be used to map and differentiate relative stiffness in postsurgical normal and pathological breast tissues. HMIFU can also successfully monitor thermal ablations in normal and pathological human breast specimens. This HMI technique may lead to a new clinical tool for breast tumor imaging and HIFU treatment monitoring.

Long-term outcomes of mandibular kinematics following class II malocclusion therapy with removable functional appliance therapy

Objective: To evaluate mandibular kinematics in class I adults following class II therapy with removable functional appliances (RFAs) during the growth period in comparison with orthodontically untreated class I and II individuals.Methods: Condylar (CRoM) and incisal range of motion (InRoM), velocity during opening and closing, and the mandibular rotation angle were recorded using an ultrasound-based jaw-tracking system in 36 test patients (mean age = 28.03 ± 6.58 years).Results: Significant group effects were found for CRoM towards the posterior in the right joint (p = 0.002) and InRoM towards the anterior (p = 0.043). The post hoc Tukey test indicates a significantly longer CRoM (posterior) for the right condyle in class II (p = 0.003) and RFA individuals (p = 0.023).Discussion: The kinematic data imply greater dentoalveolar effects due to RFA therapy than adaptive remodeling of the temporomandibular joint. The class I relationship in the RFA group following treatment indicates stable long-term outcomes.

On the Use of Ultrasound-Based Technology for Cargo Inspection

A new guided wave imaging application for fast, low-cost ultrasound-based cargo scanning system is proposed. The ultimate goal is the detection of high-atomic-number, shielding containers used to diminish the radiological signature of nuclear threats. This ultrasonic technology has the potential to complement currently deployed X-ray-based radiographic systems, thus enhancing the probability of detecting nuclear threats. An array of ultrasonic transceivers can be attached to the metallic structure of the cargo to create a guided Lamb wave. Guided medium thickness and composition variation creates reflections whose placement can be revealed by means of an imaging algorithm. The knowledge of the reflection position provides information about the shielding metallic container location inside the cargo. Moreover, due to the low coupling between metallic and nonmetallic surfaces, only the footprint of metallic containers shows up in the imaging results, thus avoiding false positives from plastic or wooden assets. As imaging capabilities are degraded if working with dispersive Lamb wave modes, the operating frequency is tuned to provide a tradeoff between low dispersion and real-time image resolution. Reflected waves in the guided domain bounds may limit the performance of imaging methods for guided media. This contribution proposes a solution based on real-time Fourier domain analysis, where plane wave components can be filtered out, thus removing nondesired contributions from bounds. Several realistic examples, scaled due to limited calculation capabilities of the available computational resources, are presented in this work, showing the feasibility of the proposed method.

Proof-of-Concept Studies for Marker-Based Ultrasound Doppler Analysis of Microvascular Anastomoses in a Modified Large Animal Model.

Background Despite attempts to solve the problem of flap monitoring, assessing the patency of vascular anastomoses postoperatively remains challenging. In addition, experimental data suggest that near-total vessel occlusion is necessary to produce significant changes in clinical appearance or monitoring devices. We sought to develop an ultrasound-based system that would provide definitive data on anastomotic function. Methods A system was developed consisting of a resorbable marker made from poly-lactic-co-glycolic acid (PLGA) implanted during the time of surgery coupled with ultrasound software to detect the anastomotic site and perform Doppler flow analysis. Surgical procedures consisting of microvascular free tissue transfer or femoral vessel cutdown were performed followed by marker placement, closure, and ultrasound monitoring. Transient vascular occlusion was produced via vessel-loop constriction. Permanent thrombosis was induced via an Arduino-controlled system applying current to the vessel intima. Results Four surgeries (one femoral vessel cutdown and three microvascular tissue transfer) were successfully performed in Yorkshire swine. The markers were readily visualized under ultrasound and provided a bounding area for Doppler analysis as well as orientation guidance. Transient spasm and partial occlusion were detected based on changes in Doppler data, while complete occlusion was evident as the total loss of color Doppler. Conclusion In this preliminary report, we have conceptualized and developed a novel system that enables the real-time visualization of vascular pedicle flow at the bedside using Doppler ultrasound and a surgically implanted marker. In a large animal model, use of the system allowed identification of the anastomosis, flow analysis, and real-time detection of flow loss.

Prospective multicenter study of ultrasound-based measurements of fetal head station and position throughout labor.

To assess the relationship between fetal head position and head station during labor, as measured using an ultrasound-based system, and the occurrence of occiput posterior (OP) position at delivery. This was an international prospective observational study including women who delivered between January 2009 and September 2013 in four centers: one in Brooklyn, NY, USA; one in Haifa, Israel; and two in Paris, France. We used an ultrasound-based system (LaborPro) to monitor fetal head station and position non-invasively throughout labor. We collected data on demographics, labor parameters and outcome. A total of 595 women were included. In 563 (94.6%) women, fetal head position at delivery was occiput anterior (OA), in 31 (5.2%) it was OP and in one (0.2%) it was occiput transverse. In 89% of pregnancies with intrapartum OP when fetal head station was above -2, the head position turned to OA at delivery; the equivalent figures were 74% and 63% OA at delivery when intrapartum OP was diagnosed at head stations of -2 to < 0, and 0 and below, respectively. Cesarean delivery was performed in 35% of pregnancies with fetal head in OP position at delivery, as opposed to 10% of those with non-OP position at delivery. On retrospective analysis, all deliveries in OP were already in OP at station -2 and below. In this first assessment of fetal head position at delivery according to fetal head position at various station levels, our data show that 100% of OP positions at delivery were already in OP position at station -2 and below. We did not observe rotation from a non-OP to an OP position from station -2 and below. Nearly two-thirds of fetuses in OP at station 0 and below will rotate to an OA position for delivery.

Ultrasound-guided spinal injections: a feasibility study of a guidance system.

Facet joint injections of analgesic agents are widely used to treat patients with lower back pain. The current standard-of-care for guiding the injection is fluoroscopy, which exposes the patient and physician to significant radiation. As an alternative, several ultrasound guidance systems have been proposed, but have not become the standard-of-care, mainly because of the difficulty in image interpretation by the anesthesiologist unfamiliar with the complex spinal sonography. We introduce an ultrasound-based navigation system that allows for live 2D ultrasound images augmented with a patient-specific statistical model of the spine and relating this information to the position of the tracked injection needle. The model registration accuracy is assessed on ultrasound data obtained from nine subjects who had prior CT images as the gold standard for the statistical model. The clinical validity of our method is evaluated on four subjects (of an ongoing in vivo study) which underwent facet joint injections. The statistical model could be registered to the bone structures in the ultrasound volume with an average RMS accuracy of 2.3±0.4 mm. The shape of the individual vertebrae could be estimated from the US volume with an average RMS surface distance error of 1.5±0.4 mm. The facet joints could be identified by the statistical model with an average accuracy of 5.1 ± 1.5 mm. The results of this initial feasibility assessment suggest that this ultrasound-based system is capable of providing information sufficient to guide facet joint injections. Further clinical studies are warranted.

Development of a New Ultrasound-Based System for Tracking Motion of the Human Lumbar Spine: Reliability, Stability and Repeatability during Forward Bending Movement Trials

The aim of this study was to develop a new method for quantifying intersegmental motion of the spine in an instrumented motion segment L4–L5 model using ultrasound image post-processing combined with an electromagnetic device. A prospective test–retest design was employed, combined with an evaluation of stability and within- and between-day intra-tester reliability during forward bending by 15 healthy male patients. The accuracy of the measurement system using the model was calculated to be ± 0.9° (standard deviation = 0.43) over a 40° range and ± 0.4 cm (standard deviation = 0.28) over 1.5 cm. The mean composite range of forward bending was 15.5 ± 2.04° during a single trial (standard error of the mean = 0.54, coefficient of variation = 4.18). Reliability (intra-class correlation coefficient = 2.1) was found to be excellent for both within-day measures (0.995–0.999) and between-day measures (0.996–0.999). Further work is necessary to explore the use of this approach in the evaluation of biomechanics, clinical assessments and interventions.

Asthma Pattern Identification via Continuous Diaphragm Motion Monitoring

Ultrasound imaging has been widely used in bio-medical imaging diagnosis for a long history because of its merits: no radiation, high penetration depth, and real-time imagingcapability. In this paper, we propose an ultrasound-based system that monitors respiratory status of asthma subjects via detecting of diaphragm movement. This system implements Chan-Vese algorithm to accurately segment diaphragm area from ultrasound image sequences and extracts 1D breathing waveform by computing mutual information (MI) between two consecutive ultrasound frames. In addition, four types of respiratory signals are identified: normal breath, fast breath, apnoea, and cough, which are related to four symptoms of asthma attack and defined as the breathing templates used for early asthma detection. In experiments, the proposed system is evaluated with a public dataset from “Ultrasound image gallery” which contains nine ultrasound videos and our dataset collected by “Interson Seemore” probe which contains five ultrasound videos in the diaphragm area. The results show that Chan-Vese segmentation method is superior to the other three algorithms: adaptive thresholding, EM/MPM, and Fuzzy C Means (FCM), and MI is a feasible method to extract accurate respiratory signal and clear information of the phase of respiratory cycle from 2D images.

Assessment of Scoliotic Deformity Using Spinous Processes: Comparison of Different Analysis Methods of an Ultrasonographic System

ObjectiveThe purpose of this study was to evaluate the performance of 5 analysis methods in quantifying scoliotic deformity, using the spatial positions of SP tips acquired by a custom-developed ultrasound-based system, with different curve fitting methods and angle metrics in terms of their correlation with Cobb angle, test-retest reliability, vulnerability to digitization errors, and accuracy of identifying end vertebrae and convexity direction. MethodsThree spinal column dry bone specimens were randomly configured to 30 different scoliotic deformities. Raw spatial data of the SP tips were processed by the following 3 methods: (1) fifth-order polynomial fitting, (2) locally weighted polynomial regression (LOESS) with smoothing parameter (α) = .25, and (3) LOESS with α = .4. Angle between the 2 tangents along the spinal curve with the most positive and negative slopes (ie, posterior deformity angle) and summation of the angles formed by every 2 lines joining 3 neighboring SPs between the end vertebrae (ie, accumulating angle) were computed to quantify scoliotic deformity. Their performances were compared in terms of their correlation with Cobb angle, test-retest reliability, vulnerability to digitization errors, and accuracy of identifying end vertebrae. ResultsPosterior deformity angle calculated from the spinal curve constructed by LOESS with α = .4 excelled in every aspect of the comparison (ie, Cobb angle, test-retest reliability, vulnerability to digitization errors, and accuracy of identifying end vertebrae and convexity direction), making it the method of choice of those tested for processing the spatial data of the SP tips in this ultrasonography study using dry bone specimens. ConclusionsThe ultrasound-based system and the LOESS (0.4)–posterior deformity angle method developed for this study offer a viable technology for quantifying scoliotic deformity in a reliable and radiation-free manner. However, further validation using scoliosis subjects is needed before they can be used to quantify spinal deformity in the clinical setting.

Convergent field elastography

An ultrasound-based system for non-invasive estimation of soft tissue shear modulus will be presented. The system uses a nested pair of transducers to provide force generation and motion measurement capabilities. The outer annular element produces a ring-like ultrasonic pressure field distribution. This in turn produces a ring-like force distribution in soft tissue, whose response is primarily observable as a shear wave field. A second ultrasonic transducer nested inside the annular element monitors the portion of the shear field that converges to the center of the force distribution pattern. Propagation speed is estimated from shear displacement phase changes resulting from dilation of the forcing radius. Forcing beams are modulated in order to establish shear speed frequency dependence. Prototype system data will be presented for depths of 10–14 cm in a tissue phantom, using drive parameters within diagnostic ultrasound safety limits. [Work supported by ONR and the Neely Chair in Mechanical Engineering, Georgia Institute of Technology.]

Association of Total Atherosclerotic Burden with Progression of Penile Vascular Disease

Abstract Background: Erectile dysfunction (ED) is an early manifestation of a generalized arterial disease. The association between penile vascular disease progression and total atherosclerotic burden was investigated using a classification that incorporates ultrasonographic assessments of intima media thickness (IMT) and plaques from both the carotid and femoral arteries. Methods: Sixty-five ED patients (mean age, 56±10 yrs) were evaluated for cavernous vascular disease severity using penile Doppler ultrasound. Ultrasonographic assessments of IMT, lumen diameter, and plaques in the carotid and femoral arteries were evaluated, and patients were classified according to an ultrasound-based morphological system. Results: Based on the results of ultrasonic assessments, patients were divided into two groups—a high-score group and a low-score group. Patients in the high-score group had increased intima-media (>1.0 mm) and/or plaque in any of the four arteries. Patients in the low-score group had normal carotid ...

EP-1304: IGRT for prostate cancer with ultrasound-based system and surface imaging system: role of the two methods

EP-1304: IGRT for prostate cancer with ultrasound-based system and surface imaging system: role of the two methods

An ultrasound-based navigation system for minimally invasive neck surgery.

Future minimally invasive neck surgery requires a navigation system adapted to the actual intra-operative bedding of the patient. The detection of the bedding-caused tissue shift is essential for a safe orientation for the surgeon new endoscopic operation procedures in neck surgery. It is essential to visualize the relation between important anatomic landmarks and operation instruments at any time. Within the scientific project SACAS we focus on developing an ultrasound supported navigation system based on preoperative imaging which considers the intra-operative tissue shift. A rotatable, flexible neck-model provides the basis for our analysis to evaluate the tissue shift and to invent the new navigation system for endoscopic neck surgery. The total registration error of the system was 2 mm.

Variability of gait in the early postoperative period of total knee arthroplasty with different surgical technique

The purpose of this study was to work out an objective and sensitive method for the early postoperative period following total knee arthroplasty (TKA) in which analysis of the gait parameters is possible and also to investigate the influence of different surgical approaches for TKA on the gait during stepping in the first threemonths of the postoperative period. Three groups of patients: age-matched healthy elderly patients as a control group, patients operated upon by the conventional technique and finally by the minimally invasive technique combined with computer-assisted navigation. All three groups included ten patients. The motions of knee, shoulder and pelvis were measured by ZEBRIS ultrasound-based system preoperatively plus six and 12weeks postoperatively. From the joint motion, the variability of cadence, and the variability of knee joint motion and that of pelvis and shoulder girdle was determined. Osteoarthritis (OA) of the knee joint and TKA using both operation techniques significantly influenced the variability of stepping parameters compared to the controls. In the early postoperative period a significant difference was detected between the two groups of the operated patients in all parameters. Our data prove that our method seems appropriate to provide objective measurement of the gait in the early postoperative period. The variability of motion of the patient groups approaches that of the healthy control group steadily, but does not reach them.

Computer-Assisted Percutaneous Renal Access Using Intraoperative Ultrasonography

This paper develops an ultrasound-based surgical navigation system for percutaneous renal intervention. The proposed system integrates preoperative magnetic resonance (MR) planning with intraoperative ultrasonography (US) slices, where the MR imagery is registered to the calibrated US data. The interventional punctures can be performed under a visualized guidance interface. We describe this navigation system in details and evaluate the navigated intervention via a phantom model.

An ultrasound-based system for temperature distribution measurements in injection moulding: system design, simulations and off-line test measurements in water

The polymer melt temperature in the screw ante-chamber of an injection moulding machine influences a number of parameters during the polymer process and therefore the final product quality. For measurement of this temperature, a sensor must be non-invasive (because of the axial moved screw during the injection of the plasticized polymer into the mould) and withstand the high pressure (>1000 bar) and temperature (>200 °C) during the injection moulding process. It is well known that the temperature of the polymer melt in the screw ante-chamber is inhomogeneous, and for that reason the sensor system must be able to measure the temperature spatially resolved. Due to the fact that sound velocity is temperature dependent, we developed a non-invasive tomography system using the transit times of ultrasonic pulses along different sound paths for calculating the temperature distribution in a polymer melt. Simulation results and example experiments at a test measurement setup are shown. Moreover, different strategies for the ultrasonic probe design (buffer rods, generation of wide beam angle) are discussed. The results of the proposed system are important for the validation of numerical simulations, a better understanding of the plasticizing process and can be used for the input of a novel temperature control system.