Clear identification of bone structures is crucial for ultrasound-guided lumbar interventions, but it can be challenging due to the complex shapes of the self-shadowing vertebra anatomy and the extensive background speckle noise from the surrounding soft tissue structures. Therefore, in this work, we will present our method for estimating the vertebra bone surfaces by using a spatiotemporal U-Net architecture learning from the B-Mode image and aggregated feature maps of hand-crafted filters. Additionally, we are integrating this solution with our patch-like wearable ultrasound system to capture the repeating anatomical patterns and image the bone surfaces from multiple insonification angles. 3D bone representations can then be created for interventional guidance. The methods are evaluated on spine phantom image data collected by our proposed “Patch” scanner, and our systematic ablation experiment shows that improved accuracy can be achieved with the proposed architecture. Equipped with this surface estimation network, our wearable ultrasound system can potentially provide intuitive and accurate interventional guidance for clinicians in an augmented reality setting.
Lumbar punctures (LPs) are interventional procedures that are used to collect cerebrospinal fluid. Since the target window is small, physicians have limited success conducting the procedure. The procedure is especially difficult for obese patients due to the increased distance between bone and skin surface. We propose a simple and direct needle insertion platform, enabling image formation by sweeping a needle with a single ultrasound element at the tip. The needle-shaped ultrasound transducer can not only sense the distance between the tip and a potential obstacle, such as bone, but also visually locate the structures by combining transducer location tracking and synthetic aperture focusing. The concept of the system was validated through a simulation that revealed robust image reconstruction under expected errors in tip localization. The initial prototype was built into a 14 G needle and was mounted on a holster equipped with a rotation shaft allowing one degree-of-freedom rotational sweeping and a rotation tracking encoder. We experimentally evaluated the system using a metal-wire phantom mimicking high reflection bone structures and human spinal bone phantom. Images of the phantoms were reconstructed, and the synthetic aperture reconstruction improved the image quality. These results demonstrate the potential of the system to be used as a real-time guidance tool for improving LPs.
Lumbar punctures (LPs) are interventional procedures used to collect cerebrospinal fluid (CSF), a bodily fluid needed to
diagnose central nervous system disorders. Most lumbar punctures are performed blindly without imaging guidance.
Because the target window is small, physicians can only accurately palpate the appropriate space about 30% of the time
and perform a successful procedure after an average of three attempts. Although various forms of imaging based
guidance systems have been developed to aid in this procedure, these systems complicate the procedure by including
independent image modalities and requiring image-to-needle registration to guide the needle insertion. Here, we propose
a simple and direct needle insertion platform utilizing a single ultrasound element within the needle through dynamic
sensing and imaging. The needle-shaped ultrasound transducer can not only sense the distance between the tip and a
potential obstacle such as bone, but also visually locate structures by combining transducer location tracking and back
projection based tracked synthetic aperture beam-forming algorithm. The concept of the system was validated through
simulation first, which revealed the tolerance to realistic error. Then, the initial prototype of the single element
transducer was built into a 14G needle, and was mounted on a holster equipped with a rotation tracking encoder. We
experimentally evaluated the system using a metal wire phantom mimicking high reflection bone structures and an actual
spine bone phantom with both the controlled motion and freehand scanning. An ultrasound image corresponding to the
model phantom structure was reconstructed using the beam-forming algorithm, and the resolution was improved
compared to without beam-forming. These results demonstrated the proposed system has the potential to be used as an
ultrasound imaging system for lumbar puncture procedures.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.