Evolution of photodynamic medicine based on fluorescence image-guided diagnosis using indocyanine green and 5-aminolevulinic acid

Fluorescence spectral analysis and logistic regression modeling for diagnosing basal cell carcinoma on head and neck

The optical fluorescence method is distinguished by key features such as non-invasiveness, high sensitivity, and resolution, which are superior to traditional diagnostic approaches. Unlike histopathological examinations and biochemical analyses, optical diagnostic methods obviate the need for tissue sampling, enabling the analysis of virtually unlimited material. The research aims to examine the effectiveness of emission spectra analysis in the diagnosis of basal cell carcinoma (BCC) of the scalp and neck. The analysis was based on data provided by Specialized Hospital No. 2 in Bytom comprising a study sample of 10 patients. For each patient, fluorescence emission spectra were recorded from each of 512 points along a 5 mm line. The results obtained from the histopathological examination, the analysis and morphological evaluation of the tissue, and the diagnosis through microscopic observation were used to define a dichotomous variable (presence or absence of a cancerous lesion), adopted in the study as the modeled variable. The next step of the presented study involved constructing a logistic regression model for identifying cancerous lesions depending on the biochemical indicator's relative fluorescence value (RFV) and emission wavelength (ELW) within the 620 nm to 730 nm range. This wavelength range is often used in fluorescence diagnostics to detect various pathologies, including cancerous lesions. The resulting binary logistic regression model, logit(p)=-33.17+0.04ELW+0.01RFV, indicates a statistically significant relationship between wavelength and relative fluorescence values with the probability of detecting cancer. The estimated model exhibits a good fit and high predictive accuracy. The overall model accuracy is 84.8 %, with the correct classification rates at approximately 96 % for healthy individuals and 74 % for individuals with cancer. These findings underscore the potential of photodynamic diagnostics in cancer detection and monitoring.

Changes in choroidal hemodynamics of form-deprivation myopia in Guinea pigs

PURPOSE

We studied changes in the choroid, particularly variation in blood flow, during the development of myopia. The hemodynamic mechanism in play remains unclear. We evaluated blood flow by quantitating indocyanine green (ICG) fluorescence in a guinea pig model of form-deprivation myopia.

METHODS

Guinea pigs were divided into form-deprivation myopia (FDM) and normal control (NC) groups. Ocular biometric and choroidal hemodynamics parameters were quantitatively derived via ICG imaging, and included the maximal ICG fluorescence intensity (Imax), rising time (Trising), blood flow index (BFI), and mean transit time (MTT).

RESULTS

Form deprivation was associated with significant interocular differences in terms of both refractive error and axial length. ICG fluorescence hemodynamic maps of fundal blood flow and vasculature density were evident. In deprived eyes, the fluorescence signals exhibited significantly longer Trising and MTT but lower Imax and BFI than fellow eyes and NC group. The interocular differences in terms of the ocular biometric and hemodynamic parameters were significantly correlated. Hemodynamic analysis of choriocapillaris lobules revealed weakened fluorescence intensity and prolonged arrival and filling times in deprived eyes. Form deprivation reduced the number of lobulated choriocapillaris structures.

CONCLUSION

Form-deprivation myopia triggered changes in the hemodynamic and vascular network structures of the choroid and choriocapillaris. The ICG fluorescence imaging/analysis method provides a unique tool for further myopia research.

Ready vascular permeability of a near-infrared fluorescent agent ASP5354 for intraoperative ureteral identification enables imaging of carcinoma tissues

This study investigates the ability of a near-infrared fluorescence (NIRF) imaging agent, ASP5354, for in vivo fluorescence imaging of esophageal squamous cell carcinoma (ESCC) tissues. The ability of ASP5354 was evaluated using a single dose of ASP5354 or indocyanine green (ICG), which was intravenously administered to a KYSE850 human ESCC xenograft mouse model. Subsequently, in vivo NIRF images of the mouse were obtained using a clinically available camera system. ASP5354-specific NIRF signals were strongly detectable in KYSE850 carcinoma tissues immediately (30 s) following ASP5354 administration compared with normal tissues. Meanwhile, ICG could not distinguish between normal and carcinomatous tissues. To elucidate the associated imaging mechanisms, the vascular permeability of ASP5354 and ICG was investigated in rat back dermis treated with saline or histamine, which enhances vascular permeability, using in vivo NIRF imaging. ASP5354 exhibited higher vascular permeability in histamine-treated skin than in normal skin. KYSE850 carcinoma tissues can be distinguished from normal tissues based on the measurement of ASP5354-specific NIRF signals, and the mechanism that enables imaging relies on the specific and rapid leakage of ASP5354 from the capillaries into the stroma of carcinoma tissues.

In vivo near-infrared fluorescence imaging of gastric cancer in an MKN-45 gastric cancer xenograft mouse model using intraoperative ureteral identification agent ASP5354

Accurate intraoperative identification of gastric cancer lesions and determination of the extent of resection are important for curability and function preservation. This study aimed to investigate the potential of the near-infrared fluorescence (NIRF) imaging agent ASP5354 for in vivo fluorescence imaging of gastric cancer. The capability of ASP5354 was evaluated using an MKN-45 human gastric cancer xenograft mouse model. A single dose of ASP5354 was intravenously administered to the mice at a concentration of 120 nmol (0.37 mg)/kg body weight. In vivo NIRF images of the mouse backs were obtained using an NIRF camera system. Moreover, the cancer tissues were dissected, and the NIRF intensity in the tissue sections was measured using the NIRF camera system. ASP5354 uptake in MKN-45 cells was assessed in vitro using the NIRF microscope. The NIRF signal of ASP5354 was selectively detected in gastric cancer tissues immediately after the intravenous administration of ASP5354. The cancer tissues emitted stronger NIRF signals than adjacent normal tissues. The difference in the NIRF intensity between the normal and cancer tissues was clearly observed at the boundary between them in the macrolevel NIRF images. Cancer tissues can be distinguished from normal tissues based on the measurement of the NIRF of ASP5354, using an NIRF camera system. ASP5354 is a promising agent for NIRF imaging of gastric cancer tissues.

Intraoperative Imaging Techniques to Improve Surgical Resection Margins of Oropharyngeal Squamous Cell Cancer: A Comprehensive Review of Current Literature

Inadequate resection margins in head and neck squamous cell carcinoma surgery necessitate adjuvant therapies such as re-resection and radiotherapy with or without chemotherapy and imply increasing morbidity and worse prognosis. On the other hand, taking larger margins by extending the resection also leads to avoidable increased morbidity. Oropharyngeal squamous cell carcinomas (OPSCCs) are often difficult to access; resections are limited by anatomy and functionality and thus carry an increased risk for close or positive margins. Therefore, there is a need to improve intraoperative assessment of resection margins. Several intraoperative techniques are available, but these often lead to prolonged operative time and are only suitable for a subgroup of patients. In recent years, new diagnostic tools have been the subject of investigation. This study reviews the available literature on intraoperative techniques to improve resection margins for OPSCCs. A literature search was performed in Embase, PubMed, and Cochrane. Narrow band imaging (NBI), high-resolution microendoscopic imaging, confocal laser endomicroscopy, frozen section analysis (FSA), ultrasound (US), computed tomography scan (CT), (auto) fluorescence imaging (FI), and augmented reality (AR) have all been used for OPSCC. NBI, FSA, and US are most commonly used and increase the rate of negative margins. Other techniques will become available in the future, of which fluorescence imaging has high potential for use with OPSCC.

Near-infrared fluorophores methylene blue for targeted imaging of the stomach in intraoperative navigation

Near-infrared (NIR) fluorescence imaging-guided surgery is increasingly concerned in gastrointestinal surgery because it can potentially improve clinical outcomes. This new technique can provide intraoperative image guidance for surgical margin evaluation and help surgeons examine residual lesions and small tumors during surgery. NIR fluorophores methylene blue (MB) is a promising fluorescent probe because of its safety and intraoperative imaging in the clinic. However, whether MB possesses the potential to perform intraoperative navigation of the stomach and gastric tumors needs to be further explored. Therefore, the current study mainly validated MB's usefulness in animal models' intraoperative imaging of stomach and gastric tumors. NIR fluorophores MB can exhibit specific uptake by the gastric epithelial cells and cancer cells. It is primarily found that MB can directly target the stomach in mice. Interestingly, MB was applied for the NIR imaging of gastric cancer cell xenografts, suggesting that MB cannot specifically target subcutaneous and orthotopic gastric tumors in xenograft models. Thus, it can be concluded that MB has no inherent specificity for gastric tumors but specificity for gastric tissues. Apparently, MB-positive and negative NIR imaging are meaningful in targeting gastric tissues and tumors. MB is expected to represent a helpful NIR agent to secure precise resection margins during the gastrectomy and resection of gastric tumors.

Mapping Lymph Node during Indocyanine Green Fluorescence-Imaging Guided Gastric Oncologic Surgery: Current Applications and Future Directions

Huge strides have been made in the navigation of gastric cancer surgery thanks to the improvement of intraoperative techniques. For now, the use of indocyanine green (ICG) enhanced fluorescence imaging has received promising results in detecting sentinel lymph nodes (SLNs) and tracing lymphatic drainages, which make it applicable for limited and precise lymphadenectomy. Nevertheless, issues of the lack of specificity and unpredictable false-negative lymph nodes were encountered in gastric oncologic surgery practice using ICG-enhanced fluorescence imaging (ICG-FI), which restrict its application. Here, we reviewed the current application of ICG-FI and assessed potential approaches to improving ICG-FI.

Theranostics Using Indocyanine Green Lactosomes

Lactosomes™ are biocompatible nanoparticles that can be used for cancer tissue imaging and drug delivery. Lactosomes are polymeric micelles formed by the self-assembly of biodegradable amphiphilic block copolymers composed of hydrophilic polysarcosine and hydrophobic poly-L-lactic acid chains. The particle size can be controlled in the range of 20 to 100 nm. Lactosomes can also be loaded with hydrophobic imaging probes and photosensitizers, such as indocyanine green. Indocyanine green-loaded lactosomes are stable for long-term circulation in the blood, allowing for accumulation in cancer tissues. Such lactosomes function as a photosensitizer, which simultaneously enables fluorescence diagnosis and photodynamic therapy. This review provides an overview of lactosomes with respect to molecular design, accumulation in cancer tissue, and theranostics applications. The use of lactosomes can facilitate the treatment of cancers in unresectable tissues, such as glioblastoma and head and neck cancers, which can lead to improved quality of life for patients with recurrent and unresectable cancers. We conclude by describing some outstanding questions and future directions for cancer theranostics with respect to clinical applications.

pH-Activatable Cyanine Dyes for Selective Tumor Imaging Using Near-Infrared Fluorescence and Photoacoustic Modalities

Photoacoustic (PA) imaging is an emerging molecular imaging modality that complements fluorescence imaging and enables high resolution within deep tissue. Fluorescence/PA multimodality imaging would be a powerful technique to extract more comprehensive information from targets than traditional single-modality imaging. In this paper, we developed a new pH-activatable sensor, CypHRGD, which is applicable to both fluorescence and PA detection. CypHRGD was derived from our previous near-infrared pH-sensing platform, in which substitution with a bulky phenyl group and functionalization with a cRGD peptide remarkably improved the sensor's biocompatibility with attenuated dye aggregation. The multimodality imaging applications of CypHRGD were demonstrated in cultured cells and cancer-xenografted mice with rapid kinetics and high sensitivity and specificity, which relies on cRGD-facilitated tumor targeting, probe accumulation and subsequent activation in the acidic organelles after endocytosis.