Intra-Arterial Image Guidance With Optical Frequency Domain Reflectometry Shape Sensing

Abstract

Intra-arterial liver cancer therapies such as transarterial chemoembolization (TACE) are the preferred therapeutic approaches for advanced hepatocellular carcinoma (HCC). However, these palliative techniques are challenging for delivering therapeutic agents selectively in the tumor without real-time 3D visualization of the catheter within the hepatic arteries. The objective of this work is to develop and evaluate in preclinical tests an advanced interventional guidance platform using a distributed strain sensing device based on optical frequency domain reflectometry (OFDR) to track the tip and shape of a catheter. The scattering properties of a fiber triplet are enhanced by focusing an ultraviolet beam on these fibers, producing a fully-distributed strain sensor, which avoids interpolation errors observed with traditional shape tracking systems. A 3D roadmap of the hepatic arteries is obtained from a combined fully convolutional and residual networks trained on MR angiography, and combined with a 4D flow dynamic sequence enabling to map blood flow velocities. An anisotropic curvature matching method is proposed to map the sensed data onto pre-operative MR and using 3D ultrasound to correct for non-rigid deformations. Experiments were conducted in a controlled environment setting, as well as in both synthetic phantoms and in 5 porcine models to assess the performance for device navigation, yielding satisfactory tracking accuracy with 3D mean errors of 2.8 ± 0.9 mm. We present the first pilot study of MR-compatible UV-exposed OFDR optical fibers for non-ionizing device guidance in intra-arterial procedures, with the potential of avoiding multiple hospitalizations required to perform invasive selective chemoembolizations.

Performance Analysis of Scattering-Level Multiplexing (SLMux) in Distributed Fiber-Optic Backscatter Reflectometry Physical Sensors

“…Virtually, the whole digestive apparatus (about 900 cm) can be covered by dedicating an 8-16 channel SLMux for each directional strain, according to the performance analysis. Similar considerations can be drawn for cardiovascular devices [22], which operate over few tens of centimeters of length. Clearly, such sensing systems can be arranged by proper geometrical design of the fibers around the medical apparatus; this analysis shows the feasibility of such architecture.…”

“…Similarly, strain sensing requires 3-4 fibers (typically, three fibers for shape sensing, four fibers when temperature compensation is also accounted [22]) for each device under test. The epidural needle investigated in [21] requires interrogation over an 8 cm length, which is easily achieved by each fiber configuration.…”

“…This approach has been, so far, reported for the measurement of strain [18] and shape [21] on a medical needle, and for a planar temperature measurement in a mini-invasive thermotherapy [19]. This scenario is sketched in Figure 1, while OBR has been presently used with fibers arranged in an arbitrary shape, or using a switch to multiplex multiple fibers in time [17,22], SLMux is the only method that allows a simultaneous scan of multiple sensing fibers. findings; Section 5 analyzes a range-extension to high-scattering fibers using FBGs; Section 6 discusses the results of the performance analysis in the light of the biomedical applications; finally, Section 7 draws the conclusions.…”

“…(a) The fiber is displaced in a 2D/3D configuration, as in [15]; this is impractical for several medical devices, due to limited spacing, tight bending and excessive mechanical torsions of the fiber. (b) The alternative is to use a 1 × N switch (TDM arrangement), to single out each individual channel [17,22]; in this arrangement, the OBR loses a large portion of real-time sensing, due to the significant increase of measurement time (N-fold increase, with ideal switches and optimal software), well over 1 s. (c) The SLMux setup [18,19], presented in this work; the switch is substituted by a splitter, hence the detection is simultaneous and real-time (0.3 s). A network of single-mode fiber delayers and high-scattering fiber multiplex from a single fiber to the N-size sensing network, each constituted by a distributed sensor.…”

“…This approach has been, so far, reported for the measurement of strain [ 18 ] and shape [ 21 ] on a medical needle, and for a planar temperature measurement in a mini-invasive thermotherapy [ 19 ]. This scenario is sketched in Figure 1 , while OBR has been presently used with fibers arranged in an arbitrary shape, or using a switch to multiplex multiple fibers in time [ 17 , 22 ], SLMux is the only method that allows a simultaneous scan of multiple sensing fibers.…”