Alternative intraoperative optical imaging modalities for fluorescence angiography in gastrointestinal surgery: spectral imaging and imaging photoplethysmography

Abstract

Introduction: Intraoperative near-infrared fluorescence angiography with indocyanine green (ICG-FA) is a well-established modality in gastrointestinal surgery. Its main drawback is the application of a fluorescent agent with possible side effects for patients. The goal of this review paper is the presentation of alternative, non-invasive optical imaging methods and their comparison with ICG-FA. Material and methods: The principles of ICG-FA, spectral imaging and, imaging photoplethysmography (iPPG), and their applications in gastrointestinal surgery are described based on selected published works. Results: The main applications of the three modalities are the evaluation of tissue perfusion, the identification of risk structures, and tissue segmentation or classification. While the ICG-FA images are mainly evaluated visually, leading to subjective interpretations, quantitative physiological parameters and tissue segmentation are provided in spectral imaging and iPPG. The combination of ICG-FA and spectral imaging is a promising method. Conclusions: Non-invasive spectral imaging and iPPG have shown promising results in gastrointestinal surgery. They can overcome the main drawbacks of ICG-FA, i.e. the use of contrast agent, the lack of quantitative analysis, repeatability, and a difficult standardization of the acquisition. Further technical improvements and clinical evaluations are necessary to establish them in daily clinical routine.

Использование Визуализирующей Интраоперационной Фотоплетизмографии И Icg-Флуоресценции У Пациентов С Колоректальным Раком

“…Однако ввиду дороговизны не каждый медицинский центр имеет возможность приобретения и использования данной методики. Изображения ICG-флуоресценции обычно оцениваются визуально, что приводит к субъективной интерпретации [31]. Также следует отметить необходимость внутривенного или паратуморального введения пациентам контрастного вещества, что может ограничить круг допустимых лиц и привезти к развитию аллергических или побочных явлений.…”

Imaging lung tissue absorption in thoracoscopy surgery from coherent multiple scattering of near-infrared light

“…Another tissue absorption measurement technique is Photoplethysmography (PPG) [16], which uses dual-wavelength to measure the oxygen saturation signal (SpO2) pulsoxymetrically. The imaging PPG (iPPG) technology has recently been developed for tissue perfusion measurement in endoscopic applications [17]. However, in thoracoscopy imaging, it is hard to perform the iPPG due to the spontaneous movements of lung tissue.…”