内窥光学相干层析成像：前沿进展与临床应用（特邀）

Significance Optical coherence tomography (OCT) is a high-resolution, minimally invasive imaging technique based on lowcoherence interferometry, providing imaging depths of 1‒3 mm and resolution at the micron level. It is an optical imaging technique that bridges the gap between ultrasound imaging and confocal microscopy. Unlike traditional imaging methods, OCT enables high-precision imaging of tissues based on their natural optical properties without the need for external contrast agents, offering significant advantages in non^-invasive medical imaging diagnostics. Traditional diagnostic methods for the digestive tract, respiratory system, and blood vessels primarily rely on white light endoscopy for surface morphological observation. However, the imaging capability of white light endoscopy is limited by its shallow imaging depth, making it difficult to reveal pathological changes in deeper layers, such as the submucosa. This limitation has spurred research into combining endoscopy with OCT. Endoscopic OCT devices, which integrate OCT imaging with endoscopic technology, can access the lumen of the body and visualize the microscopic structure of internal tissues in real^-time. These devices provide high-resolution near-histologic quality cross^-sectional and volumetric images, revealing subtle changes in diseased areas. As a result, endoscopic OCT is often referred to as“optical biopsy,”and its advent marks a significant breakthrough in the application of optical imaging technology in medicine, offering new tools for early disease detection and treatment. Early^-time domain OCT systems had the disadvantage of long signal acquisition time. However, with the introduction of frequency^-domain OCT, imaging speeds have increased dramatically, further enhancing the clinical value of endoscopic OCT. Advances in miniaturization technology, MEMS (microelectromechanical systems), and novel optical fiber manufacturing processes have allowed endoscopic OCT probes to achieve compact sizes while maintaining excellent imaging capabilities, significantly improving their applicability in complex and narrow body cavities. Over the years, endoscopic OCT has evolved from traditional structural imaging to intelligent, functional, and multimodal integrated imaging systems, opening up broader possibilities for precision medicine in the future. Therefore, summarizing existing research findings is crucial to providing a rational guide for future developments. Progress We provide a systematic review of the development history of endoscopic OCT, first summarizing key technological and clinical breakthroughs along a timeline. Based on this, we divide the major evolutionary phases of OCT into five parts: the germination and validation phase, the technological breakthrough and initial application phase, the high-speed and multi^-scene application phase, the multimodal and functional phase, and the intelligent and clinical translation phase. Next, we further analyze the key technological advancements in endoscopic OCT. These include miniaturization techniques aimed at reducing probe size while ensuring imaging performance, such as ultra^-thin 3D printing technology and liquid-shaping techniques. We also highlight the emergence of new endoscopic technologies, such as capsule endoscopy, which enables better delivery and imaging within the human body. Following this, we discuss multimodal imaging techniques that complement the limitations of single OCT imaging. These technologies include fluorescence imaging, which offers high sensitivity and specificity for malignant tumor lesions, ultrasound imaging, which provides deeper penetration, near^-infrared spectroscopy for tissue chemical analysis, and photoacoustic imaging, which combines high-contrast optical imaging with deep penetration ultrasound imaging. In recent years, advancements in active manipulation and intelligent technologies for endoscopes have also been made to better adapt to the complex anatomy of the human body. In the future, the integration of endoscopic OCT with robotic technology and artificial intelligence may enable semi^-autonomous navigation and targeted therapy, further unlocking the potential of endoscopic OCT. In terms of clinical applications, we introduce representative studies of endoscopic OCT in cardiovascular and cerebrovascular systems, including coronary artery atherosclerosis imaging, cardiovascular imaging analysis combined with artificial intelligence, and the endoscopic probe for cerebrovascular imaging. Endoscopic OCT is also applicable to deep brain imaging, helping to analyze the structural and functional patterns of neural circuits and providing reliable positional guidance for deep brain surgeries. In the digestive and respiratory systems, endoscopic OCT can provide layered information of luminal structures, revealing subtle features such as glands beneath the surface layer. In the urological and reproductive systems, endoscopic OCT can also identify tissue structures and provide valuable imaging for cancer diagnosis and biopsy. Emerging clinical applications include laser ablation for minimally invasive treatments and in vivo tissue biopsies guided by OCT. Laser ablation guided by OCT ensures precise targeting of tumor areas, allowing real^-time monitoring of tumor damage, and facilitating accurate removal of the target while minimizing damage to surrounding healthy tissues. OCT-guided biopsies can effectively eliminate the blindness inherent in traditional biopsy methods, improving diagnostic accuracy. These emerging applications signify a shift from diagnostic tools to guiding platforms for minimally invasive interventions. Conclusions and Prospects Endoscopic OCT has evolved from a laboratory prototype into an important imaging tool in certain medical specialties. The technological progression provides a clear paradigm and engineering experience for future innovations. In the future, endoscopic OCT will further contribute to early diagnosis and treatment and play an essential role in precision medicine.