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Minimizing OCT quantification error via a surface-tracking imaging probe
Hyeon-Cheol Park1, Ang Li1, Honghua Guan2
1Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21215, USA.
Abstract:
OCT-based quantitative tissue optical properties imaging is a promising technique for intraoperative brain cancer assessment. The attenuation coefficient analysis relies on the depth-dependent OCT intensity profile, thus sensitive to tissue surface positions relative to the imaging beam focus. However, it is almost impossible to maintain a steady tissue surface during intraoperative imaging due to the patient's arterial pulsation and breathing, the operator's motion, and the complex tissue surface geometry of the surgical cavity. In this work, we developed an intraoperative OCT imaging probe with a surface-tracking function to minimize the quantification errors in optical attenuation due to the tissue surface position variations. A compact OCT imaging probe was designed and engineered to have a long working distance of ∼ 41 mm and a large field of view of 4 × 4 mm2 while keeping the probe diameter small (9 mm) to maximize clinical versatility. A piezo-based linear motor was integrated with the imaging probe and controlled based upon real-time feedback of tissue surface position inferred from OCT images. A GPU-assisted parallel processing algorithm was implemented, enabling detection and tracking of tissue surface in real-time and successfully suppressing more than 90% of the typical physiologically induced motion range. The surface-tracking intraoperative OCT imaging probe could maintain a steady beam focus inside the target tissue regardless of the surface geometry or physiological motions and enabled to obtain tissue optical attenuation reliably for assessing brain cancer margins in challenging intraoperative settings.
Insights
This study introduces a novel intraoperative optical coherence tomography (OCT) probe with surface-tracking capabilities. This innovation significantly improves the accuracy of brain cancer margin assessment by minimizing motion-related errors during surgery.
Area of Science:
- Biomedical Optics
- Surgical Technology
- Neuro-oncology
Background:
- Optical coherence tomography (OCT) enables quantitative imaging of tissue optical properties for intraoperative brain cancer assessment.
- Accurate analysis of attenuation coefficients is crucial but sensitive to variations in tissue surface position relative to the OCT imaging focus.
- Physiological motions and complex surgical cavity geometry impede maintaining a stable tissue surface during intraoperative procedures.
Purpose of the Study:
- To develop an intraoperative OCT imaging probe with integrated surface-tracking functionality.
- To minimize quantification errors in optical attenuation measurements caused by dynamic tissue surface position variations.
- To enhance the reliability of brain cancer margin assessment in challenging surgical environments.
Main Methods:
- Engineered a compact OCT imaging probe with a long working distance (∼41 mm) and wide field of view (4×4 mm²), maintaining a small diameter (9 mm).
- Integrated a piezo-based linear motor for real-time surface position feedback control, inferred from OCT images.
- Implemented a GPU-assisted parallel processing algorithm for real-time tissue surface detection and tracking, suppressing >90% of physiological motion.
Main Results:
- The developed surface-tracking OCT probe successfully maintained a stable beam focus within the target tissue, irrespective of surface geometry or physiological motion.
- Achieved reliable tissue optical attenuation measurements, crucial for accurate intraoperative assessment.
- Demonstrated significant suppression of motion-induced artifacts, enhancing imaging consistency.
Conclusions:
- The surface-tracking intraoperative OCT imaging probe offers a robust solution for overcoming motion-related challenges in quantitative optical property imaging.
- This technology enables reliable assessment of brain cancer margins during surgery, improving clinical decision-making.
- The probe's design enhances clinical versatility for various intraoperative applications.
