Table of Contents

Echospine

Last updated: May 8, 11:03 PM

Summary

Background, Specific Aims, and Significance

Lumbar puncture (spinal tap) is the process by which physicians insert an epidural needle between the bone structures of the vertebra in order to collect cerebrospinal fluid. A lumbar puncture can help diagnose serious infections, such as meningitis; other disorders of the central nervous system, such as Guillain-Barre syndrome and multiple sclerosis; or cancers of the brain or spinal cord. However, physicians must avoid blood vessels, nerves, and bone without visibility. The physician palpates to locate the interspace between L2-L3, L3-L4, or L4-L5, then inserts the needle slightly cephalad into the interspace. The physician slowly advances the needle until they sees the fluid return. The position and angle to insert the needle are especially difficult to determine on obese patients. Error in the position and angle of the needle results in reattempt and sometimes complications. Conventional ultrasound guidance requires the practitioner to search for the gaps between vertebrae using an ultrasound transducer, mark insertion point, then insert blindly. Our goal is to make a device that can image the spinal column, allow us to determine the insertion point, and track the needle throughout insertion all in real time.

Deliverables

Technical Approach

In our work, we will extend upon the single element ultrasound needle guidance system proposed by Zhang et. al. To maintain image update during needle insertion, we move the imaging element out of the needle onto two parallel rails that are parallel to the image plane. We will continue to use the backpropagation-based synthetic tracked aperture focusing, which mitigates the low frame-rate problem by updating the image as soon as each new A-line is acquired. To address the low visibility of the needle in B-mode image, we will keep an ultrasound source (PZT/PA) on the tip of the needle to enable triangulation with the ultrasound elements on the rails. Each of the rails contains one large (5mm dia) and sensitive ultrasound element with 5 MHz center frequency or a low-element-count (~8) array facing the skin of the patient. The rails are parallel to the spine and centered on the midline of the patient. The element or array can move in 1 degree of freedom.

Dependencies

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Milestones and Status

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Reports and presentations

Project Bibliography

Other Resources and Project Files

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