Position Of Ultrasound Probe Research Articles

Six-Degree-of-Freedom Freehand 3D Ultrasound: A Low-Cost Computer Vision-Based Approach for Orthopedic Applications.

In orthopedics, X-rays and computed tomography (CT) scans play pivotal roles in diagnosing and treating bone pathologies. Machine bulkiness and the emission of ionizing radiation remain the main problems associated with these techniques. The accessibility and low risks related to ultrasound handling make it a popular 2D imaging method. Indeed, 3D ultrasound assembles 2D slices into a 3D volume. This study aimed to implement a probe-tracking method for 6 DoF 3D ultrasound. The proposed method involves a dodecahedron with ArUco markers attached, enabling computer vision tracking of the ultrasound probe's position and orientation. The algorithm focuses on the data acquisition phase but covers the basic reconstruction required for data generation and analysis. In the best case, the analysis revealed an average error norm of 2.858 mm with a standard deviation norm of 5.534 mm compared to an infrared optical tracking system used as a reference. This study demonstrates the feasibility of performing volumetric imaging without ionizing radiation or bulky systems. This marker-based approach shows promise for enhancing orthopedic imaging, providing a more accessible imaging modality for helping clinicians to diagnose pathologies regarding complex joints, such as the shoulder, replacing standard infrared tracking systems known to suffer from marker occlusion problems.

Registration between 2D and 3D Ultrasound Images to Track Liver Blood Vessel Movement.

For the accurate positioning of surgical tools, conventional intraoperative navigation systems have been developed to recognize the relationship between target positions and the tools. However, since an internal organ is deformed during the operation, registration between realtime two-dimensional (2D) ultrasound images and three-dimensional (3D) CT or MRI images is not always effective. Therefore, this study developed image registration between 2D and 3D ultrasound images considering deformation for tracking target vessel movement in the liver. 3D ultrasound image was obtained in advance with 3D coordinates, including the target vessel. Then real-time 2D images and ultrasound probe position were simultaneously acquired using a 3D position sensor. We applied multiple image resolution registration, where rapid and fine optimizations can be expected at higher and lower levels, respectively. Meanwhile, the gradient descent method was adopted for the optimization, which determines the relative arrangements to obtain maximum similarity between 2D and 3D images. We experimentally established resolution level parameters using a phantom before applying it to track liver blood vessel movements in a normal healthy subject. Comparing the 2D images and the registered images, although the approach has some limitations in tracking large displacement, we confirmed that the cross-section of the target blood vessel was clearly visualized. This method has the potential for an ultrasound therapy targeting blood vessels under natural respiration conditions.

CAL-Tutor: A HoloLens 2 Application for Training in Obstetric Sonography and User Motion Data Recording.

Obstetric ultrasound (US) training teaches the relationship between foetal anatomy and the viewed US slice to enable navigation to standardised anatomical planes (head, abdomen and femur) where diagnostic measurements are taken. This process is difficult to learn, and results in considerable inter-operator variability. We propose the CAL-Tutor system for US training based on a US scanner and phantom, where a model of both the baby and the US slice are displayed to the trainee in its physical location using the HoloLens 2. The intention is that AR guidance will shorten the learning curve for US trainees and improve spatial awareness. In addition to the AR guidance, we also record many data streams to assess user motion and the learning process. The HoloLens 2 provides eye gaze, head and hand position, ARToolkit and NDI Aurora tracking gives the US probe positions and an external camera records the overall scene. These data can provide a rich source for further analysis, such as distinguishing expert from novice motion. We have demonstrated the system in a sample of engineers. Feedback suggests that the system helps novice users navigate the US probe to the standard plane. The data capture is successful and initial data visualisations show that meaningful information about user behaviour can be captured. Initial feedback is encouraging and shows improved user assessment where AR guidance is provided.

Trajectory estimation of ultrasound images based on convolutional neural network

Estimating ultrasound probe position and consequently its image position is challenging in image registration and reconstruction concept. On the other hand, in the last few years, the convolutional neural network has had a huge impact on the image processing concept. In this study, we proposed a new network modality. The proposed model attempts to employ the benefits of both the densely connected network and FlowNet for estimating the position information of the ultrasound images. Furthermore, for reducing implementation costs, the inertial measurement unit was utilized. Definition of the images to the networks’ input relies on stack manner. Evaluation of the network’s results was completed in three stages: in the first stage, the comparison is made between proposed network performance with two different image sequences, whereby the proposed model has better performance with a stack of three sequences; in the second stage, the network performance was compared with the conventional method, whereby results indicate better performance, especially in rotation angels; and finally, in the third stage, we attempted to answer how is that the network performance if instead of inertial measurement unit, transformation matrix computed with conventional feature extracting methods. According to the acquired results—utilizing conventional methods with three and five sequence networks performance reduces the amount of absolute mean square error in comparison to stage two results. Especially the amount of this reduction is significant in Euler angels’ estimation. However, the network has better performance while the transformation matrix is computed with IMU's information.

Design, Development and Validation of a Knee Brace to Standardize the US Imaging Evaluation of Knee Osteoarthritis.

Objective: A repeatable and reliable follow-up of knee injuries would be desirable to prevent delayed diagnosis and to monitor the efficacy of the applied treatment over time. Ultrasound (US) techniques are an attractive option to this purpose, since they are safe, low-cost and non-invasive. However, its use in the clinical practice is limited by the high dependency on the operator’s experience. Hence, the objective of this study is to provide a standardization of the US image acquisition process for knee osteoarthritis (OA) allowing an extended clinical use of US technologies in this domain. Methods: Clinical specifications were provided by expert musculoskeletal radiologists thus identifying the subject poses and the US probe positions needed to evaluate the cartilage structure, signs of synovitis and joint effusion. Such considerations were used to derive the technical requirements needed for the development of a wearable brace equipped with specific openings to guide the correct placement of the probe. The feasibility of the developed wearable brace was tested on three healthy volunteers, which were asked to acquire informative US images, similar to the reference images performed by the musculoskeletal radiologist. Results: Thanks to the knee brace, the untrained subjects were able to self-acquire informative B-mode images comparable to the corresponding images acquired by an expert clinician. Discussion/Conclusion: The use of a knee brace intended for knee OA US diagnosis demonstrated the possibility to standardize the acquisition protocol and make its application achievable also for untrained subjects, representing a key step toward tele-ultrasonography.

Ultrasound Probe Positions for Internal Jugular Vein Cannulation: A Prospective Study of Different Techniques.

We compared sonoanatomy of the internal jugular vein (IJV) the high (HA), conventional (CA) and the medial oblique approach (MA) to identify the best approach and head position for IJV cannulation. Total of 45 volunteers aged 18-65 years were included in this study. The degree of overlap in percentage, depth of IJV from skin, antero-posterior (AP) and transverse diameters (TD) of IJV were measured in real time with ultrasound (US). Measurements were taken in the HA, CA and MA in neutral and 30° head rotation on both the right and left side of the neck. The HA had lower percentage of overlap when compared to CA and MA in neutral and 30° head rotation (p= 0.002 to ≤0.001). The IJV was more shallow in the CA and MA. The AP and TD of the IJV were larger in the MA when compared to HA (p=<0.001) and CA (p =0.026 to < 0.001) and the right IJV has a larger AP and TD in all approaches. The HA had the least percentage of overlap compared to CA and MA, therefore the risk of accidental ICA puncture can be reduced. The apparent overlap seen in MA may not reflect the actual scenario because of the way the US beam cuts the vessel. The AP and TD of IJV were significantly increased in the MA, which would ease CVC. We conclude and recommend the medial oblique probe position with 30° head rotation provides optimal real time sonographic parameters for US guided IJV cannulation.

Focused ultrasound in out-of-hospital cardiac arrest by advanced paramedics

Background: This study describes and evaluates advanced paramedic practitioner (APP) use of focused cardiac ultrasound (FoCUS) in out-of-hospital cardiac arrest (OHCA), and relates ultrasound findings with decisions to terminate resuscitation. The authors report characteristics of patients who do/do not undergo a FoCUS examination by APPs, ultrasound probe positions used and whether FoCUS findings were associated with decisions to terminate resuscitation or to convey patients to an emergency department (ED) with ongoing resuscitation. Method: A retrospective, observational cohort study of all adult medical OHCA patients attended by APPs in Greater London during 2018 was carried out using data from EMS and APP databases. Results: Twenty-eight APPs attended 1444 OHCA patients in 2018, of whom 744 underwent FoCUS. The subcostal probe position was used most frequently (74%), followed by the parasternal long axis (19%), with significantly smaller use of the parasternal short axis and apical windows. Absence of spontaneous cardiac motion (SCM) was associated with resuscitation being terminated (333 out of 391; 85%) and the presence of SCM was associated with conveyance to the emergency department (213 out of 264 patients; 80%). All decisions to terminate resuscitation were within the APP scope of practice. Conclusion: The authors believe this is the largest prehospital study involving FoCUS in OHCA. An association between FoCUS findings and decisions made to either convey patients to hospital or terminate resuscitation was found. The SC window was most used and ROLE decisions were deemed to be in accordance with local guidance and practice.

Focused ultrasound in out-of-hospital cardiac arrest by advanced paramedics

Background: This study describes and evaluates advanced paramedic practitioner (APP) use of focused cardiac ultrasound (FoCUS) in out-of-hospital cardiac arrest (OHCA), and relates ultrasound findings with decisions to terminate resuscitation. The authors report characteristics of patients who do/do not undergo a FoCUS examination by APPs, ultrasound probe positions used and whether FoCUS findings were associated with decisions to terminate resuscitation or to convey patients to an emergency department (ED) with ongoing resuscitation. Method: A retrospective, observational cohort study of all adult medical OHCA patients attended by APPs in Greater London during 2018 was carried out using data from emergency medical services (EMS) and APP databases. Results: Twenty-eight APPs attended 1444 OHCA patients in 2018, of whom 744 underwent FoCUS. The subcostal probe position was used most frequently (74%), followed by the parasternal long axis (19%), with significantly smaller use of the parasternal short axis and apical windows. Absence of spontaneous cardiac motion (SCM) was associated with resuscitation being terminated (333 out of 391; 85%) and the presence of SCM was associated with conveyance to the emergency department (213 out of 264 patients; 80%). All decisions to terminate resuscitation were within the APP scope of practice. Conclusion: The authors believe this is the largest prehospital study involving FoCUS in OHCA. An association between FoCUS findings and decisions made to either convey patients to hospital or terminate resuscitation was found. The SC window was most used and ROLE decisions were deemed to be in accordance with local guidance and practice.

Autonomous Robotic Point-of-Care Ultrasound Imaging for Monitoring of COVID-19-Induced Pulmonary Diseases.

The COVID-19 pandemic has emerged as a serious global health crisis, with the predominant morbidity and mortality linked to pulmonary involvement. Point-of-Care ultrasound (POCUS) scanning, becoming one of the primary determinative methods for its diagnosis and staging, requires, however, close contact of healthcare workers with patients, therefore increasing the risk of infection. This work thus proposes an autonomous robotic solution that enables POCUS scanning of COVID-19 patients’ lungs for diagnosis and staging. An algorithm was developed for approximating the optimal position of an ultrasound probe on a patient from prior CT scans to reach predefined lung infiltrates. In the absence of prior CT scans, a deep learning method was developed for predicting 3D landmark positions of a human ribcage given a torso surface model. The landmarks, combined with the surface model, are subsequently used for estimating optimal ultrasound probe position on the patient for imaging infiltrates. These algorithms, combined with a force–displacement profile collection methodology, enabled the system to successfully image all points of interest in a simulated experimental setup with an average accuracy of 20.6 ± 14.7 mm using prior CT scans, and 19.8 ± 16.9 mm using only ribcage landmark estimation. A study on a full torso ultrasound phantom showed that autonomously acquired ultrasound images were 100% interpretable when using force feedback with prior CT and 88% with landmark estimation, compared to 75 and 58% without force feedback, respectively. This demonstrates the preliminary feasibility of the system, and its potential for offering a solution to help mitigate the spread of COVID-19 in vulnerable environments.

Use of Ultrathin Bronchoscope on a Need Basis Improves Diagnostic Yield of Difficult-to-Approach Pulmonary Lesions.

There are cases of peripheral lung nodules that are difficult to approach despite using ancillary diagnostic devices during multimodal bronchoscopy. The use of ultrathin bronchoscopes has shown superiority over standard thin bronchoscopes. We retrospectively evaluated whether substitution of the thin-bronchoscope by the ultrathin device during multimodal bronchoscopy improves lesion ultrasound visualization and diagnostic yield in patients with difficult-to-approach pulmonary lesions. The study comprised 44 out of 338 patients that underwent multimodal bronchoscopy at Matsusaka Municipal Hospital. The thin-bronchoscope with an external diameter of 4 mm was substituted by the ultrathin-bronchoscope with an external diameter of 3 mm when the radial endobronchial ultrasound showed that the probe position was not within the target lesion. The median diameter of the pulmonary tumors was 17.5 mm (range: 6.0–5.2.0 mm). The endobronchial ultrasound showed the probe's position adjacent to the lesion in 12 cases and no visible lesion in 32 cases using a thin-bronchoscope. However, the endobronchial ultrasound views changed from adjacent to the lesion to within the lesion in nine cases, from no visible lesion to within the lesion in 17 cases, and from no visible lesion to adjacent to the lesion in nine cases after bronchoscope substitution. After substitution, the diagnostic yield was 80.8% in cases with the radial probe within the target lesion, 72.7% in cases with the probe adjacent to the target lesion, and 0% in cases with no visible lesion. The overall diagnostic yield was 65.9% after bronchoscope substitution. The substitution of the thin bronchoscope by the ultrathin device on a need basis improves the position of the radial endobronchial ultrasound probe and diagnostic yield of pulmonary lesions during multimodal diagnostic bronchoscopy.

Acute Care: Pain Management

Pain is a chief complaint in more than 50% of emergency department (ED) visits. Injury accounts for approximately one-third of presentations associated with pain; other common diagnoses include neck and back pain, minor infections, abdominal pain, and headache. In the ED, pain is underdiagnosed and undertreated, and existing pain management practices in the ED are inconsistent. Inadequate pain management is common, and pain remains unchanged or worsens during the ED visit for more than 40% of patients. Patient satisfaction improves when expectations for pain control are met. This review covers the pathophysiology of pain and the practice of pain management. Figures show the approach to pain management in the ED, an example of a numerical and visual analog scale pain rating scale, field block of the pinna, ultrasound probe and hand position for ultrasound-guided regional anesthesia, regional anesthesia of the face, innervation of the hand and fingers, regional anesthesia of the median, radial and ulnar nerves, innervation of the foot, ultrasound-guided regional anesthesia of the posterior tibialis nerve, regional anesthesia of the sural nerve, and method of regional anesthesia of the dorsal foot. This review contains 13 figures, 16 tables, and 72 references. Key words: Acute pain, Pain management, Oligoanalgesia, Pain assessment, Inadequate pain management, Acute pain management, Pain management in the emergency department, Pain in the ED, Pain presentation

Automatic Normal Positioning of Robotic Ultrasound Probe Based Only on Confidence Map Optimization and Force Measurement

Acquiring good image quality is one of the main challenges for fully-automatic robot-assisted ultrasound systems (RUSS). The presented method aims at overcoming this challenge for orthopaedic applications by optimizing the orientation of the robotic ultrasound (US) probe, i.e. aligning the central axis of the US probe to the tissue's surface normal at the point of contact in order to improve sound propagation within the tissue. We first optimize the in-plane orientation of the probe by analyzing the confidence map of the US image. We then carry out a fan motion and analyze the resulting forces estimated from joint torques to align the central axis of the probe to the normal within the plane orthogonal to the initial image plane. This results in the final 3D alignment of the probe's main axis with the normal to the anatomical surface at the point of contact without using external sensors for surface reconstruction or localizing the point of contact in an anatomical atlas. The algorithm is evaluated both on a phantom and on human tissues (forearm, upper arm and lower back). The mean absolute angular difference (±STD) between true and estimated normal on stationary phantom, forearm, upper arm and lower back was 3.1 ± 1.0°, 3.7 ± 1.7°, 5.3 ± 1.3° and 6.9 ± 3.5°, respectively. In comparison, six human operators obtained errors of 3.2 ± 1.7° on the phantom. Hence the method is able to automatically position the probe normal to the scanned tissue at the point of contact and thus improve the quality of automatically acquired ultrasound images.

Acute Care: Pain Management

Pain is a chief complaint in more than 50% of emergency department (ED) visits. Injury accounts for approximately one-third of presentations associated with pain; other common diagnoses include neck and back pain, minor infections, abdominal pain, and headache. In the ED, pain is underdiagnosed and undertreated, and existing pain management practices in the ED are inconsistent. Inadequate pain management is common, and pain remains unchanged or worsens during the ED visit for more than 40% of patients. Patient satisfaction improves when expectations for pain control are met. This review covers the pathophysiology of pain and the practice of pain management. Figures show the approach to pain management in the ED, an example of a numerical and visual analog scale pain rating scale, field block of the pinna, ultrasound probe and hand position for ultrasound-guided regional anesthesia, regional anesthesia of the face, innervation of the hand and fingers, regional anesthesia of the median, radial and ulnar nerves, innervation of the foot, ultrasound-guided regional anesthesia of the posterior tibialis nerve, regional anesthesia of the sural nerve, and method of regional anesthesia of the dorsal foot. This review contains 13 figures, 15 tables, and 71 references. Key words: Acute pain, Pain management, Oligoanalgesia, Pain assessment, Inadequate pain management, Acute pain management, Pain management in the emergency department, Pain in the ED, Pain presentation

DESIGN AND PERFORMANCE EVALUATION OF PASSIVE INTERLOCKING POSTURE ADJUSTMENT MECHANISM FOR TRANSRECTAL ULTRASOUND PROBE

In the current prostate biopsy procedure, it is necessary for the doctor to hold the ultrasonic probe during the entire process. This increases the fatigue degree of the doctor, and the motion of the ultrasonic probe is more likely to cause damage to the anus of the patient. A medical device that can assist doctors in prostate scans and biopsy puncture devices was developed. We focused on the passive interlocking transrectal ultrasonic probe posture adjustment mechanism. Based on the posture adjustment mechanism, a passive interlocking transrectal ultrasound probe position and posture adjustment mechanism capable of assisting the doctor in prostate scanning and puncture intervention was designed. The passive interlocking posture adjustment mechanism with a seven-degree-of-freedom (DOF) interlocking mechanism was designed and can meet the requirements of doctors. The physical prototype of the passive interlocking transrectal ultrasonic probe posture adjustment mechanism was developed and commissioned. The locking torque and braking torque of the mechanism were measured. The results showed that the ultrasonic probe can achieve reliable locking and effectively meet the operation requirements.

Feasibility Study of Simultaneous MR and 4D Ultrasound Imaging for IGRT

This work aimed to assess the feasibility of simultaneous MR and ultrasound image acquisition of healthy volunteers as part of a cost-effective and non-invasive real-time motion management solution for liver image-guided radiotherapy (IGRT). Pre-treatment simultaneous ultrasound and MR image datasets will be used to characterize respiratory motion states of salient features during free-breathing image acquisitions. These features will be tracked during treatment using ultrasound and mapped to the pre-treatment dataset to provide real-time motion management. While other motion management solutions exist, many have one or more drawbacks such as employing a high cost system, requiring invasive implants for imaging, adding dose to the patient, or potentially compromising on accuracy by utilizing optical tracking of external motion. Nine healthy volunteers were included in this study. For this IGRT project, we developed the first hands-free, MR-compatible, and real-time e4D ultrasound probe. The maximum depth is 18 cm with 2 mm lateral resolution at 7 cm depth. In 3D mode at 18 cm depth, the frame rate is 4 fps. The ultrasound was positioned either sub- or intercostally in order to view vasculature in the liver and a strap technique was utilized for probe stabilization. For this study, the harmonic mode (1.7/3.3 MHz) was employed. A fast spoiled gradient echo sequence (FSPGR) was used to obtain multi-phase 2D sagittal image slices. Nine consecutive sagittal slices were acquired for each volunteer. During acquisition, both datasets were streamed to an external machine for processing and analysis. After the scan, the data was synchronized using temporal image information. The image data was then analyzed using ITK-Snap and DICOM Slicer. Simultaneous ultrasound and MR images were successfully acquired and synchronized from nine volunteers. There were no major artifacts in either the ultrasound or MR images. Minor low level susceptibility artifacts within 1-2 cm of the ultrasound probe position were visible in the MR for some of the images acquired; such artifacts have not inhibited image analysis nor have they impacted overall image quality. Preliminary analyses do not provide evidence of drift over the course of ultrasound data acquisition, implying the position of the ultrasound is stable over the course of imaging. Limitations with internal over-heating of the ultrasound were experienced. We found that heating is mediated by lowering the acoustic power and allowing cooling time between slices of MR data. This study demonstrates the feasibility of simultaneous ultrasound and MR image acquisition using a hands-free, MR-compatible, 4D ultrasound transducer. While the current project looks to apply this technology specifically to liver IGRT, there may be opportunities for more broad application in IGRT as well as other image guidance procedures.

Feasibility of Image Registration for Ultrasound-Guided Prostate Radiotherapy Based on Similarity Measurement by a Convolutional Neural Network.

Purpose:Registration of 3-dimensional ultrasound images poses a challenge for ultrasound-guided radiation therapy of the prostate since ultrasound image content changes significantly with anatomic motion and ultrasound probe position. The purpose of this work is to investigate the feasibility of using a pretrained deep convolutional neural network for similarity measurement in image registration of 3-dimensional transperineal ultrasound prostate images.Methods:We propose convolutional neural network-based registration that maximizes a similarity score between 2 identical in size 3-dimensional regions of interest: one encompassing the prostate within a simulation (reference) 3-dimensional ultrasound image and another that sweeps different spatial locations around the expected prostate position within a pretreatment 3-dimensional ultrasound image. The similarity score is calculated by (1) extracting pairs of corresponding 2-dimensional slices (patches) from the regions of interest, (2) providing these pairs as an input to a pretrained convolutional neural network which assigns a similarity score to each pair, and (3) calculating an overall similarity by summing all pairwise scores. The convolutional neural network method was evaluated against ground truth registrations determined by matching implanted fiducial markers visualized in a pretreatment orthogonal pair of x-ray images. The convolutional neural network method was further compared to manual registration and a standard commonly used intensity-based automatic registration approach based on advanced normalized correlation.Results:For 83 image pairs from 5 patients, convolutional neural network registration errors were smaller than 5 mm in 81% of the cases. In comparison, manual registration errors were smaller than 5 mm in 61% of the cases and advanced normalized correlation registration errors were smaller than 5 mm only in 25% of the cases.Conclusion:Convolutional neural network evaluation against manual registration and an advanced normalized correlation -based registration demonstrated better accuracy and reliability of the convolutional neural network. This suggests that with training on a large data set of transperineal ultrasound prostate images, the convolutional neural network method has potential for robust ultrasound-to-ultrasound registration.

Wrist ultrasound - the model method for grey-scale and power Doppler scoring

The use of ultrasound (US) has been at the forefront of aiding diagnosis of inflammatory arthritis since its introduction. More recently, US imaging in patients with clinical remission appears to...

A virtual environment for ultrasound examination learning

ABSTRACTIn this study, we propose a virtual learning environment for ultrasonography gestures based on an ultrasound (US) learning database. The learning database is comprised of US probe position and orientation, US images and force applied on the skin for each image. The intermediate images were inferred using the set of two-dimensional (2D) US images acquired at various force levels by the mean of interpolation method. A force feedback joystick with three degrees of freedom is used to monitor the applied forces. The proposed virtual environment was able to overcome the lack of immersion of the learner in the existing systems, especially, the US image deformation and force feedback feeling. In addition to the low cost, our system simulates, accurately, the US exam ensuring a good immersion to the learner with all senses involved in the US exam. An intelligent agent supervises the learner through the whole process. The virtual environment was evaluated by experts and trainees, and the results are presented and discussed.

Comparison of transverse short-axis classic and oblique long-axis "Syringe-Free" approaches for internal jugular venous catheterization under ultrasound guidance

There are different ultrasound probe positions used for internal jugular venous catheter placement. Also, in-plane or out of plane needle approach may be used for catheterization. Transverse short-axis classic approach is the most popular performed approach in literature. "Syringe-Free" is a new described technique that is performed with oblique long-axis approach. We aimed to compare performance of these two approaches. This study was conducted as a prospective and randomized study. 80 patients were included the study and divided into two groups that were named Group C (transverse short-axis classic approach) and Group SF (oblique long-axis syringe-free approach) by a computer-generated randomization. The primary outcome was mean time that guidewire is seen in the internal jugular vein (performing time). The secondary outcomes were to compare number of needle pass, number of skin puncture and complications between two groups. Demographic and hemodynamic data were not significantly different. The mean performing time was 54.9±19.1s in Group C and 43.9±15.8s in Group SF. Significant differences were found between the groups (p=0.006). Mean number of needle pass was 3.2(±2.1) in Group C and 2.1(±1.6) in Group SF. There were statistically significant differences between two groups (p=0.002). The number of skin puncture was 1.6(±0.8) and 1.2(±0.5) in Group C and SF, respectively (p=0.027). "Syringe-Free" technique has lower performing time, number of needle pass and skin puncture. Also, it allows to follow progress of guide-wire under continuous ultrasound visualization and the procedure does not need assistance during catheter insertion. Namely, "Syringe-Free" is effective, safe and fast technique that may be used to place internal jugular venous catheter.

How I do it: feasibility of a new ultrasound probe fixator to facilitate high quality stress echocardiography

BackgroundStress echocardiography (SE) has recently regained momentum as an important diagnostic tool for the assessment of both ischemic and non-ischemic heart disease. Performing SE during physical exercise is challenging due to a suboptimal patient position and vigorous movements of the patient’s chest. This hampers a stable ultrasound position and reduces the diagnostic performance of SE. A stable ultrasound probe position would facilitate producing high quality images during continuous measurements. With Probefix (Usono, Eindhoven, The Netherlands), a newly developed tool to fixate the ultrasound probe to the patient’s chest, stabilization of the probe during physical exercise is possible.Implementation and resultsThe technique of SE with the Probefix and its’ feasibility are evaluated in a small pilot study. Probefix fixates the ultrasound probe to the patient’s chest, using two chest straps and a fixation device. The ultrasound probe position and angle may be altered with a relative high degree of freedom. We tested the Probefix for continuous echocardiographic imaging in 12 study subjects during supine and upright ergometer stress tests. One patient was unable to perform exercise and in two study subjects good quality images were not achieved. In the other patients (82%) a stable probe position was obtained, with subsequent good quality echocardiographic images during SE.ConclusionWe have demonstrated the feasibility of the Probefix support during ergometer tests in supine and upright positions and conclude that this external fixator may facilitate continuous monitoring of cardiac function in a group of patients.