Autonomous Real-Time Interventional Scan Plane Control With a 3-D Shape-Sensing Needle

Abstract

This study demonstrates real-time scan plane control dependent on three-dimensional needle bending, as measured from magnetic resonance imaging (MRI)-compatible optical strain sensors. A biopsy needle with embedded fiber Bragg grating (FBG) sensors to measure surface strains is used to estimate its full 3-D shape and control the imaging plane of an MR scanner in real-time, based on the needle’s estimated profile. The needle and scanner coordinate frames are registered to each other via miniature radio-frequency (RF) tracking coils, and the scan planes autonomously track the needle as it is deflected, keeping its tip in view. A 3-D needle annotation is superimposed over MR-images presented in a 3-D environment with the scanner’s frame of reference. Scan planes calculated based on the FBG sensors successfully follow the tip of the needle. Experiments using the FBG sensors and RF coils to track the needle shape and location in real-time had an average root mean square error of 4.2 mm when comparing the estimated shape to the needle profile as seen in high resolution MR images. This positional variance is less than the image artifact caused by the needle in high resolution SPGR (spoiled gradient recalled) images. Optical fiber strain sensors can estimate a needle’s profile in real-time and be used for MRI scan plane control to potentially enable faster and more accurate physician response.

Recent developments in fibre optic shape sensing

“…Post 2000's, the developed methods have been widely used on various structures and applications [35,41]. One of the most practical and successful examples that has been used in industry is FOSS on surgical needles and catheters since 2010 [40,[42][43][44][45][46][47][48][49].…”

“…Using commercially available SSMF, FBGs and interrogator systems has been particularly of interest to develop application specific FOSS. Many shape-sensing research projects have used a triangular FBG arrangement for shape sensing [42,[44][45][46][47][48][96][97][98][99], helically wrapped single fibres [100], parallel fibres [101] and an orthogonal fibre arrangement [102,103]. A comprehensive review of these works, which summarises different shape sensing approaches using standard single-mode, is reported in literature [85].…”

Endoluminal ultrasound applicators for MR‐guided thermal ablation of pancreatic tumors: Preliminary design and evaluation in a porcine pancreas model

“…Temperature monitoring slices were prescribed using two approaches: manually, using a scout scan in the RTHawk interface to localize the applicator and determine alignment or automatically using the coordinates of the two active tracking coils. 27 One thermometry slice was positioned sagittal to the applicator transducer fixture to visualize the longitudinal extent of heating, and one to three were prescribed along the axial plane through the transducer stage. All slices were 5 mm in thickness with 1 mm gap between parallel slices, chosen to capture planes through the center of each transducer and the transducer assembly fixture.…”

Enhancement of accuracy in shape sensing of surgical needles using optical frequency domain reflectometry in optical fibers

“…Therefore, medical applications have incorporated FBGs in biopsy needles [12], catheters and other minimally invasive tools for shape detection and force sensing [13]. Medical robotics for image guided prostate biopsies has also used shape sensing to track needle deflections during insertions [14].…”