New Breakthrough in the Field of Cerebral Vascular Diseases: Clinical Application of Small Optical Coherence Tomography Imaging Probe

Academic Background and Research Motivation

In recent years, interventional treatment has become the preferred method for cerebrovascular diseases such as cerebral aneurysm, ischemic stroke, arterial dissection, and intracranial atherosclerotic disease (ICAD). However, current imaging technologies have limitations in spatial resolution and contrast, leading to difficulties in accurate diagnosis and treatment monitoring. Common imaging techniques like digital subtraction angiography (DSA), computed tomography (CT), and magnetic resonance imaging (MRI) cannot adequately display arterial wall lesions, aneurysm morphology, and detailed conditions of implanted devices. Additionally, complications during or after the surgery, such as thrombosis or device non-adherence to the arterial wall, are challenging to detect with existing technologies.

To overcome these challenges, it is necessary to develop an imaging technology capable of accurately displaying arterial tissues and metallic devices at high resolution. Optical coherence tomography (OCT) offers high sensitivity, high dynamic range, and high-resolution imaging capabilities, providing detailed in situ volumetric microscopy images. It has been widely applied in coronary artery disease. Nevertheless, existing imaging catheters are not suitable for safely navigating and reliably displaying the complex intracranial arterial anatomy of the human brain. To address this issue, this study developed a flexible, small endoscope device—neuro OCT (NOCT) probe—and applied it in humans for the first time, aiming to achieve high-resolution imaging of complex cerebral vasculature.

Authors and Source of the Paper

This research paper was authored by Vitor M. Pereira et al., who are affiliated with St. Michael’s Hospital, Toronto, Canada; Clínica Sagrada Familia, Buenos Aires, Argentina; and the University of Massachusetts Chan Medical School, Worcester, USA. The paper was published in the May 15, 2024, issue of the journal Science Translational Medicine.

Research Process

Subjects and Methods

The study was conducted on 32 patients undergoing neurovascular interventional treatment. The NOCT probe is a highly miniaturized and mechanically flexible device capable of providing artifact-free images in the complex vascular environment of the brain. The NOCT system utilizes fast-rotating near-infrared laser for Fourier domain imaging, achieving an axial resolution close to 10 micrometers. The probe has an outer diameter of 0.39 millimeters and can be delivered to the target arterial segment via a standard neurovascular microcatheter with a 0.021-inch inner diameter. Temporary contrast agent injection is employed to clear blood from the arterial lumen for image quality. Within 2 seconds, the probe rotates and retracts rapidly, capturing the arterial wall and implanted device in a helical light pattern.

Major Experimental Results

NOCT’s high-resolution imaging successfully achieved volumetric microscopy of the arteries in the anterior and posterior circulations of the brain. This includes distal segments of the internal carotid artery (ICA), middle cerebral artery (MCA), vertebral artery, basilar artery, and posterior cerebral artery. Pathologies captured include cerebral aneurysms, ischemic stroke, arterial stenosis, arterial dissection, and intracranial atherosclerotic disease. Compared to traditional X-ray imaging methods, NOCT provides artifact-free, high-resolution visualization of intracranial arterial lesions and neurovascular devices.

In aneurysm treatment, NOCT revealed the presence of thrombus and device non-apposition in a right posterior communicating artery aneurysm. This information helped optimize medical treatment and interventional procedures. Additionally, NOCT clearly demonstrated the device configuration and microstructure of the arterial wall in evaluating recurrent aneurysms, providing more detailed diagnostic information and guiding subsequent treatment decisions.

For intracranial atherosclerotic disease, NOCT detailed the microstructure, composition, and inflammatory markers of the plaques, such as macrophage accumulation and cholesterol crystals. In acute stroke intervention and thrombectomy procedures, NOCT differentiated normal arterial appearance from pathological states including defective arterial disease and arteritis, guiding treatment planning.

Conclusion and Study Value

As a diagnostic tool, NOCT achieved high-resolution volumetric depiction in intracranial arteries, supplementing the shortcomings of existing imaging technologies. NOCT-provided information aids in optimizing neurointerventional surgery, personalizing patient management, innovating existing treatment devices and techniques, and promoting the study of related physiological mechanisms. This technology not only evaluates arterial walls, devices, and intraluminal objects but also provides high-resolution observation of subarachnoid space, penetrating arteries, and veins.

Study Highlights

1. High-Resolution Imaging: NOCT provides artifact-free, high-resolution imaging of intracranial arteries and related devices, aiding more accurate diagnosis and treatment monitoring.
2. Strong Practicality: The NOCT probe can be delivered through standard neurovascular microcatheters, compatible with existing clinical workflows.
3. Detailed Pathological Features: NOCT reveals plaque microstructure, arterial wall pathological characteristics, and thrombus formation, providing critical information for treatment planning.
4. Good Safety: In application to 32 patients, NOCT demonstrated high safety and tolerability, with no observed related acute adverse events.

Additional Information

The study detailed the application of NOCT in different clinical scenarios, including diagnosis and treatment monitoring of aneurysms, evaluation and management of intracranial atherosclerotic disease, thrombectomy process in ischemic stroke, and postoperative follow-up. The application of NOCT technology in the subarachnoid space and other anatomical regions also demonstrated its broad potential. Future research is expected to further validate NOCT’s role in improving clinical outcomes and reducing complications and explore its potential in revealing new pathological mechanisms.

Materials and Methods

Study Design: This study is an observational proof-of-concept study aimed at evaluating the application of NOCT in intracranial arteries. It did not involve randomization, blinding, or sample size calculation.

NOCT System: The imaging engine uses a central wavelength of 1300 nanometers with a fast-scan laser capturing 200,000 scan lines per second. The imaging probe has a maximum outer diameter of 0.39 millimeters and an insertion length of 190 centimeters, combined with a 0.021-inch microcatheter for targeting vessels.

Data Collection and Analysis: NOCT data were captured at a speed of 250 frames per second using rapid contrast agent injection. The study completed 75 scans (96.2% success rate), generating approximately 37,799 cross-sectional images, with a detailed analysis of image quality and related pathological features.

The results of this study indicate that NOCT technology provides unprecedented detail and diagnostic information for volumetric microscopy imaging of intracranial arteries, offering a new tool for neurointerventional surgery and the management of cerebrovascular diseases. Future studies are expected to reveal more potential and value in its clinical application.