Out-of-plane brachial plexus block with a novel SonixGPSTMneedle tracking system

Time-aware deep neural networks for needle tip localization in 2D ultrasound

PURPOSE

Accurate placement of the needle is critical in interventions like biopsies and regional anesthesia, during which incorrect needle insertion can lead to procedure failure and complications. Therefore, ultrasound guidance is widely used to improve needle placement accuracy. However, at steep and deep insertions, the visibility of the needle is lost. Computational methods for automatic needle tip localization could improve the clinical success rate in these scenarios.

METHODS

We propose a novel algorithm for needle tip localization during challenging ultrasound-guided insertions when the shaft may be invisible, and the tip has a low intensity. There are two key steps in our approach. First, we enhance the needle tip features in consecutive ultrasound frames using a detection scheme which recognizes subtle intensity variations caused by needle tip movement. We then employ a hybrid deep neural network comprising a convolutional neural network and long short-term memory recurrent units. The input to the network is a consecutive plurality of fused enhanced frames and the corresponding original B-mode frames, and this spatiotemporal information is used to predict the needle tip location.

RESULTS

We evaluate our approach on an ex vivo dataset collected with in-plane and out-of-plane insertion of 17G and 22G needles in bovine, porcine, and chicken tissue, acquired using two different ultrasound systems. We train the model with 5000 frames from 42 video sequences. Evaluation on 600 frames from 30 sequences yields a tip localization error of [Formula: see text] mm and an overall inference time of 0.064 s (15 fps). Comparison against prior art on challenging datasets reveals a 30% improvement in tip localization accuracy.

CONCLUSION

The proposed method automatically models temporal dynamics associated with needle tip motion and is more accurate than state-of-the-art methods. Therefore, it has the potential for improving needle tip localization in challenging ultrasound-guided interventions.

Ultrasonographic needle tip tracking for in-plane infraclavicular brachialis plexus blocks: a randomized controlled volunteer study

BACKGROUND

Onvision is a new technology for needle tip detection and tracking in ultrasound-guided regional anesthesia. The system consists of a piezoelectric sensor close to the needle tip and an electronic console integrated in the ultrasound system. The needle tip is visualized by a green circle on the ultrasound screen. The aim of the study was to investigate the effect of the new needle tip tracking technology on in-plane infraclavicular plexus blocks.

METHODS

The study was a randomized, controlled, observer blinded cross-over trial in 26 healthy volunteers. Two specialists in anesthesiology performed an ultrasound-guided infraclavicular lateral sagittal brachial plexus block with and without needle tip tracking. Primary outcome was procedure time, measured from insertion of the needle until local anesthesia injection was completed. Secondary outcome measures included the number of hand movements and path lengths (assessed by hand motion analysis), block success rate, onset time and duration, discomfort experienced by the volunteers, and the anesthesiologists' confidence as to whether their block would be successful or not.

RESULTS

Mean (SD) procedure time was 183.0 (56.1) s with and 206.8 (56.2) s without needle tip tracking (p=0.16). There were no significant differences in any of the secondary outcomes. Two volunteers' experienced Horner syndrome after blocks without needle tip tracking. No other adverse events occurred during the study.

CONCLUSION

Our study on needle tip tracking for infraclavicular blocks did not reveal any significant differences between active needle tip tracking and the control procedures, neither for primary outcome nor secondary outcome measurements.

TRIAL REGISTRATION NUMBER

NCT03631914.

Needle tip tracking for ultrasound-guided peripheral nerve block procedures-An observer blinded, randomised, controlled, crossover study on a phantom model

BACKGROUND

The Onvision needle tip tracking (NTT) is a new technology consisting of a needle with an ultrasound sensor close to the needle tip and a console for computerised signal processing. The aim of the study was to evaluate NTT technology during ultrasound-guided simulated peripheral nerve block procedures in a porcine phantom model.

METHODS

Forty anaesthesiologists performed in-plane and out-of-plane simulated nerve blocks with and without NTT guidance. The primary outcome measure was procedure time. Secondary outcomes were hand movements and the path length travelled by the hands measured by motion analysis, precision of the needle tip related to the target structure, success rates and violations of the target structure, and the participants confidence whether their procedure would be successful or not.

RESULTS

Procedure time was reduced from 66.7 (SD = 47.5) seconds to 43.8 (SD = 29.2) seconds when NTT was used for out-of-plane procedures (P = 0.002). The number of hand movements of the probe hand was 13.9 (SD = 30.2) with NTT and 22.8 (SD = 30.0) without NTT (P = 0.019). No significant differences were registered during the performance of in-plane procedures. The participants confidence in a presumed block success was increased with both in-plane procedures (8.50 (SD = 1.18) with NTT vs 7.65 (SD = 1.96), P = 0.004) and out-of-plane procedures (8.50 (SD = 1.09) vs 7.10 (SD = 1.89), P = 0.0001).

CONCLUSIONS

The new NTT technology significantly reduced the procedure time and the number of hand movements for ultrasound-guided out-of-plane PNB procedures. No significant differences were found for the in-plane procedures.

Effect of ultrasound image enhancement software on the quality of vision of regional anesthesia needles

BACKGROUND

Our objective was to evaluate and compare the visualization of different types of needles with or without ultrasound image enhancement software, both in biological tissues and artificial models.

METHODS

This is an observational study on fresh porcine tissue and gelatin models. Six types of plexus needles were studied. The same anesthesiologist performed in-plane punctures with each needle at 30°, 40° and 50° in both 2D mode and using software-based enhanced mode without changing position, generating 72 images. The images were evaluated blind by 38 anesthesiologists with at least two years of experience in ultrasound and rated from 0 to 10. A univariate and multivariate analysis was performed to identify differences between the images according to needle, mode, angle and experimental model. We described the results as mean (standard deviation).

RESULTS

The Echoplex needle, 8.31 (1.94), was significantly better than the Sonoplex needle, 7.53 (2.16), P=0.0003, and both were significantly better than the other needles (P<0.0001). Significant differences were also found in favor of the gelatin model, 7.26 (2.48) vs. 6.24 (3.67), P<0.0001, and with ultrasound image enhancement software, 8.59 (1.55) vs. 4.91 (3.31), P<0.0001. These differences were confirmed by multivariate analysis.

CONCLUSIONS

Although there are differences between the different types of needles used with ultrasound visualization strategies, ultrasound image enhancement software provides good visualization, regardless of the model chosen.

The new technological trends in ultrasound-guided regional anesthesia

PURPOSE OF REVIEW

Real-time two-dimensional ultrasound guidance is undoubtedly one of the most important evolutions in the field of regional anesthesia techniques, for peripheral nerve blocks and neuraxial anesthesia. The recent literature has been analyzed for studies concerning new technological trends in ultrasound-guided regional anesthesia. This review focuses on electromagnetic tracking systems for ultrasound guidance and three/four-dimensional ultrasound imaging in regional anesthesia.

RECENT FINDINGS

Electromagnetic tracking can facilitate needle-beam alignment for in-plane approaches and indicates where the needle crosses the beam during out-of-plane ultrasound-guided procedures. Three-dimensional ultrasound imaging can provide more detailed anatomical information and better spatial orientation than two-dimensional imaging. Four-dimensional ultrasound imaging enhances the visualization of a particular anatomy and offers real-time assessment of local anesthetic spread during ultrasound-guided regional anesthesia. These techniques have some limitations and drawbacks limiting their expansion.

SUMMARY

This article describes the principles, technology and development of electromagnetic tracking system for ultrasound guidance and three/four-dimensional ultrasound imaging in regional anesthesia, considering whether these new technologies will have impending applications in clinical practice.

[Seeing more : Technical innovations in regional anesthesia]

Visualization and verification are key factors since the implementation of ultrasound-guided regional anesthesia. This article reviews and discusses newer technical innovations in regional anesthesia with regard to optimization of needle guidance, improvements in needle visibility, technical improvements in ultrasound techniques and innovative technologies in regional anesthesia. Clinically available applications are presented as well as experimental tools and techniques with a potential for clinical implementation in the future. Mechanical needle guides are used to improve alignment of needle axis and ultrasound beam axis. Compound imaging technology improves needle visibility in steep needle insertion angles and is already implemented in daily clinical practice. Sonoelastography improves tissue discrimination and detection of small amounts of fluids. Benefits of 3D and 4D ultrasound in regional anesthesia are discussed as well as experimental tools for tissue discrimination, such as optical reflection spectrophotometry.