Search Results (64)

Background: Timely and accurate identification of wound infections is essential for effective management, yet remains clinically challenging. This study evaluated the utility of a near-infrared autofluorescence imaging system (Fluobeam^®, Fluoptics, Grenoble, France) and a thermal imaging system (FLIR^®, Teledyne LLC, Thousand Oaks, CA, USA) for detecting bacterial and fungal infections in chronic wounds. Fluobeam^® enables real-time visualization of microbial autofluorescence without exogenous contrast agents, whereas FLIR^® detects localized thermal changes associated with infection-related inflammation. Methods: This retrospective clinical study included 33 patients with suspected wound infections. All patients underwent autofluorescence imaging using Fluobeam^® and concurrent thermal imaging with FLIR^®. Imaging findings were compared with microbiological culture results, clinical signs of infection, and semi-quantitative microbial burdens. Results: Fluobeam^® achieved a sensitivity of 78.3% and specificity of 80.0% in detecting culture-positive infections. Fluorescence signal intensity correlated strongly with microbial burden (r = 0.76, p < 0.01) and clinical indicators, such as exudate, swelling, and malodor. Pathogens with high metabolic fluorescence, including Pseudomonas aeruginosa and Candida spp., were consistently identified. Representative cases demonstrate the utility of fluorescence imaging in guiding targeted debridement and enhancing intraoperative decision-making. Conclusions: Near-infrared autofluorescence imaging with Fluobeam^® and thermal imaging with FLIR^® offer complementary, noninvasive diagnostic insights into microbial burden and host inflammatory response. The combined use of these modalities may improve infection detection, support clinical decision-making, and enhance wound care outcomes. Full article

Maximal safe surgical resection remains a critical component of glioblastoma (GBM) management, improving both survival and quality of life. However, complete tumor removal is hindered by the infiltrative nature of GBM and its proximity to eloquent brain regions. Fluorescence-guided surgery (FGS) has emerged as a valuable tool to enhance intraoperative tumor visualization and optimize resection outcomes. Currently used fluorophores such as 5-aminolevulinic acid (5-ALA), fluorescein sodium (FS), and indocyanine green (ICG) have distinct advantages but are limited by suboptimal specificity, shallow tissue penetration, and technical constraints. 5-ALA and SF often yield unreliable signals in low-grade tumors or infiltrative regions and also pose challenges such as phototoxicity and poor depth resolution. In contrast, near-infrared (NIR) fluorescence imaging represents a promising next-generation approach, providing superior tissue penetration, reduced autofluorescence, and real-time delineation of tumor margins. This review explores the mechanisms, clinical applications, and limitations of currently approved FGS agents and highlights future directions in image-guided neurosurgery. Full article

Objective: The clinical presentation of inherited retinal dystrophies associated with pathogenic variants in PRPH2 is highly variable. Here we present bilateral sector macular dystrophy as a novel clinical phenotype. Methods and analysis: Ophthalmologic examination, detailed retinal imaging with optical coherence tomography (OCT), OCT-angiography, fundus and near-infrared autofluorescence and molecular genetic testing were performed on a 30-year-old female. Results: The patient reported the onset of subjective visual disturbances 4.5 months prior to our first examination. Clinical examination and retinal imaging revealed bilateral sharply demarcated paracentral lesions in the temporal lower macula and otherwise normal retinal findings. Patient history revealed no medication or other possible causes for these unusual retinal lesions. Molecular genetic testing revealed a heterozygous c.623G>A variation (p.(Gly208Asp)) in the PRPH2 gene. Conclusions: Bilateral sectoral macular dystrophy has not been reported previously in any inherited retinal dystrophy. This feature adds to the wide spectrum of PRPH2-associated clinical presentations. Full article

Identifying parathyroid glands during surgery is challenging and time-consuming due to their small size (3–5 mm) and camouflaged appearance in the background of the thyroid, lymph nodes, fat, and other neck structures. For the gland itself, it is also important to differentiate abnormal ones from normal ones. Accidental damage or removal of the normal glands can result in complications like hypocalcemia, which may necessitate lifelong medication dependence, and, in extreme cases, lead to death. The study of autofluorescence optical properties of normal and abnormal parathyroid glands and the surrounding tissue will be helpful for developing non-invasive detection devices. The near-infrared (NIR) autofluorescence characteristics of parathyroid and thyroid tissues have been studied extensively and are now used for parathyroid gland detection during surgery. Additionally, there have been a few reports on the UV-visible light-excited autofluorescence characteristics of these tissues with a focus on spectroscopy. However, there is a lack of high-resolution, side-by-side autofluorescence imaging comparisons of both tissue types under various excitation wavelengths, ranging from visible to NIR. We developed a standalone tabletop autofluorescence imaging system to acquire images of ex vivo specimens in the operating room under different excitation wavelengths: visible 405 nm, 454 nm, 520 nm, 628 nm, and NIR 780 nm. Autofluorescence imaging features of parathyroid adenomas for each excitation wavelength were described and compared. It was found that visible light excites much stronger autofluorescence from parathyroid adenoma tissue compared to NIR light. However, NIR excitation provides the best intensity difference/contrast between parathyroid adenoma and thyroid tissue, making it optimal for differentiating these two tissue types, and detecting parathyroid adenoma during surgery. The high fluorescent site under the NIR 780 nm excitation also generates high fluorescence under visible excitation wavelengths. Heterogeneous fluorescence patterns were observed in most of the parathyroid adenoma cases across all the excitation wavelengths. Full article

With the increasing prevalence of plastic pollution, understanding its impact on soil nematodes is crucial for environmental sustainability and food security. Traditional fluorescence-based probes have the limitations of high background noise and interference from autofluorescence. In this study, the luminous upconverted NaYF4:Yb³⁺/Er³⁺ nanoparticles acted as high-sensitivity probes for real-time visualization of ingestion and biodistribution of polystyrene microplastics (PS-MPs) and nanoplastics (PS-NPs) in Caenorhabditis elegans. The novel probes enabled efficient near-infrared-to-visible light conversion. This approach improved the precision of nano- and microplastic detection in biological tissues. Microscopic imaging revealed that the probes effectively distinguished size-dependent plastic distribution patterns, with microplastics remaining in the digestive tract, whereas nanoparticles penetrated intestinal walls and entered systemic circulation. Quantitative fluorescence analysis confirmed that PS-NPs exhibited higher bioavailability and deeper tissue penetration, providing crucial insights into plastic behavior at the organismal level. The different toxicities of PS-NPs and PS-MPs were further confirmed by measurement of the locomotor impairments and the physiological disruptions. These findings emphasize the broader applications of upconverted nanoparticles as advanced bio-imaging probes, offering a sensitive and non-invasive tool for tracking pollutant interactions in environmental and biological systems. Full article

Background: Autofluorescence can identify parathyroid glands and protect their vasculature during thyroid surgery to prevent postoperative hypoparathyroidism. This study evaluates the Burjeel intraoperative protocol using near-infrared indocyanine green (ICG-NiR) imaging to preserve parathyroid glands during total thyroidectomy. Methods: This study conducted a single-centre retrospective matched cohort analysis involving 156 consecutive patients who underwent thyroidectomy using the Burjeel ICG-guided near-infrared (NiR) fluorescence protocol (“ICG group”). Patients were matched 1:1 based on gender and extent of resection with 156 counterparts who underwent standard thyroid surgery. The Stryker Spy-phi NiR fluorescence imaging system (Stryker™, Portage, MI, USA) was utilized in three modes—green, black/white, and colourful—to facilitate real-time visualization. Post-lobectomy, each parathyroid gland was individually scored for viability before the closure of the surgical site. Patients were stratified into hypoparathyroidism and euparathyroidism groups based on the parathyroid hormone levels measured on the first postoperative day. Results: The groups had 133 women and 23 men. Preoperative factors like age (43.7 years in both groups); resection time (49 min in the ICG group versus 50 min in the conventional group); and PTH, TPO, and Vit D3 levels were not statistically different. The ICG group had a lower rate of inadvertent parathyroidectomy (9% vs. 17.9% in the standard group, chi-square test, p = 0.015), a lower rate of postoperative hypoparathyroidism (18.6% vs. 35.3%, chi-square test, p = 0.001), and higher postoperative PTH levels (t-test, p = 0.0001). Postoperative hypoparathyroidism was associated with malignant surgical pathology and malignancy on both sides (p = 0.026 and 0.01, respectively). This study found that female participants had a higher incidence of unintentional parathyroidectomy (p = 0.001) but not postoperative hypoparathyroidism. Subgroup analysis showed a negative connection between ICG score and female hypoparathyroidism. Conclusions: The new Burjeel ICG-guided NiR fluorescence approach has greatly reduced inadvertent parathyroidectomy and hypoparathyroidism in female total thyroidectomy patients. Further research is needed to identify numerical variables that aid intraoperative decision-making. Full article

Background: This study investigates the use of near-infrared fluorescence imaging (NIFI) as an alternative to intraoperative parathyroid hormone (ioPTH) measurement in patients with primary hyperparathyroidism (PHP) due to parathyroid adenoma (PA) with two preoperative imaging examinations in agreement on the position of the altered parathyroid gland. Methods: Fifty patients who underwent minimally invasive parathyroidectomy (MIP) from March 2021 to April 2024 were enrolled. MIPs utilised both NIFI and ioPTH, comparing the time to adenoma excision with NIFI against the total surgical time, including ioPTH measurement wait time. Results: Results showed successful MIPs in all patients, with a mean excision time of 44.7 min (SD ± 25.2) and a total procedure time of 85.5 min (SD ± 37.1). The median of the duration of the surgical procedure until adenoma excision was 35.0 min (IQR 38.8), while the median duration of the entire procedure was 74.5 min (IQR 40.5). This difference in medians is statistically significant using the Wilcoxon non-parametric test for paired samples (p < 0.001). The average wait for ioPTH results post-excision was 37 min (SD ± 12.2). Three fluorescence patterns were identified: “cap” (46%), heterogeneous (30%), and homogeneous (24%). Conclusions: If preoperative imaging confirms PA location, NIFI could replace ioPTH reducing surgical time without compromising success rates. Full article

Near-infrared autofluorescence (NIA) is a non-invasive retinal imaging technique used to examine the retinal pigment epithelium (RPE) based on the autofluorescence of melanin. Melanin has several functions within RPE cells. It serves as a protective antioxidative factor and is involved in the phagocytosis of photoreceptor outer segments. Disorders affecting the photoreceptor–RPE complex result in alterations of RPE cells which are detectable by alterations of NIA. NIA allows us to detect early alterations in various chorioretinal disorders, frequently before they are ophthalmoscopically visible and often prior to alterations in lipofuscin-associated fundus autofluorescence (FAF) or optical coherence tomography (OCT). Although NIA and FAF relate to disorders affecting the RPE, the findings for both imaging methods differ and the area involved has been demonstrated to be larger in NIA compared to FAF in several disorders, especially inherited retinal dystrophies (IRDs), indicating that NIA detects earlier alterations compared to FAF. Foveal alterations can be much more easily detected using NIA compared to FAF. A reduced subfoveal NIA intensity is the earliest sign of autosomal dominant Best disease, when FAF and OCT are still normal. In other IRDs, a preserved subfoveal NIA intensity is associated with good visual acuity. So far, the current knowledge on NIA in IRD has been presented in multiple separate publications but has not been summarized in an overview. This review presents the current knowledge on NIA in IRD and demonstrates NIA biomarkers. Full article

Background: Choroideremia is a monogenic inherited retinal dystrophy that manifests in males with night blindness, progressive loss of peripheral vision, and ultimately profound sight loss, commonly by middle age. It is caused by genetic defects of the CHM gene, which result in a deficiency in Rab-escort protein-1, a key element for intracellular trafficking of vesicles, including those carrying melanin. As choroideremia primarily affects the retinal pigment epithelium, fundus autofluorescence, which focuses on the fluorescent properties of pigments within the retina, is an established imaging modality used for the assessment and monitoring of affected patients. Methods and Results: In this manuscript, we demonstrate the use of both short-wavelength blue and near-infrared autofluorescence and how these imaging modalities reveal distinct disease patterns in choroideremia. In addition, we show how these structural measurements relate to retinal functional measures, namely microperimetry, and discuss the potential role of these retinal imaging modalities in clinical practice and research studies. Moreover, we discuss the mechanisms underlying retinal autofluorescence patterns by imaging with a particular focus on melanin pigment. Conclusions: This could be of particular significance given the current progress in therapeutic options, including gene replacement therapy. Full article

Objectives: The main objective of this study was to report and investigate the characteristics and longitudinal changes in dark-without-pressure (DWP) fundus lesions in patients with autoimmune diseases using multimodal imaging techniques. Methods: In this retrospective observational case series, five patients affected by ocular and systemic autoimmune disorders and DWP were examined. DWP was assessed by multimodal imaging, including color fundus photography (CFP), near-infrared reflectance (NIR), blue reflectance (BR), blue autofluorescence (BAF), optical coherence tomography (OCT), OCT-angiography (OCT-A), fluorescein angiography (FA) and indocyanine green angiography (ICGA), and functional testing, including standard automated perimetry (SAP) and electroretinography (ERG). Follow-up examinations were performed for four out of five patients (range: 6 months–7 years). Results: DWP fundus lesions were found in the retinal mid-periphery and were characterized by the hypo-reflectivity of the ellipsoid zone on OCT. DWP appeared hypo-reflective in NIR, BR and BAF, and exhibited hypo-fluorescence in FA in two patients while showing no signs in one patient. ICGA showed hypo-fluorescent margins in one patient. SAP and ERG testing did not show alterations attributable to the DWP lesion. Follow-up examinations documented rapid dimensional changes in DWP even in the short term (1 month). Conclusions: This study suggests a possible association between autoimmune diseases and DWP. New FA and ICGA features were described. The proposed pathogenesis hypotheses may operate as a basis for further investigation of a lesion that is still largely unknown. Large population studies would be necessary to confirm whether there is a higher incidence of DWP in this patient category. Full article

Fine-needle aspiration biopsy is crucial for modern diagnostics of endoscopic procedures and thus an efficient and reliable method for increasing biopsy yields is urgently needed. In our study, we address the limited availability and high price of the rapid onsite evaluation (ROSE) technique by introducing the technique of near-infrared on-site evaluation (NOSE) consisting of spectral measurement of near-infrared radiation (NIR) transmitted through the evaluated material. For this purpose, we designed a special optical probe consisting of two fibres, of which one is a source fibre and the second is a detector fibre. The distal ends of both fibres are brought together into one bundle which is, with the help of a special extension, applied to a cuvette with an analysed sample at a defined distance from the cuvette bottom and fixed in place. A portion of the NIR radiation received by the detector fibre after it propagates through the sample then depends on the optical and therefore morphological characteristics of the sample. Based on the measured spectral curve, we can calculate the attenuation coefficient curve and subsequently the parameter of the sample richness and the parameter characterising the autofluorescence peak as well. We found that the value of our introduced parameters is in significant relation to sample richness as well as to sample malignity. NOSE evaluation of EBUS/EUSb (endobronchial/oesophageal ultrasound bronchoscopy) specimens can be considered an easy new technique aiming to improve sampling diagnostic accuracy and to diminish costs related to the presence of a cytopathologist and related instrumentation in the endoscopy suite. Full article

Diabetic retinopathy is a leading cause of visual morbidity worldwide. Fundus autofluorescence is a rapid, non-invasive imaging modality that has gained increased popularity in recent years in the multimodal evaluation of diabetic retinopathy and, in particular, of diabetic macular oedema. Acquired using either a fundus camera or the confocal scanning laser ophthalmoscope, short-wavelength and near-infrared autofluorescence are the most used techniques in diabetic retinopathy. In diabetic macular oedema, short-wavelength autofluorescence, in its cystoid pattern, is useful for detecting cystoid macular oedema. Increased spot hyperautofluorescence in short-wavelength and granular changes in near-infrared autofluorescence correlate well with other imaging findings, indicating photoreceptor and retinal pigment epithelium damage and being associated with decreased visual acuity. While also being a marker of oxidative stress, increased short-wavelength autofluorescence in the setting of diabetic macular oedema appears to be a prognostic factor for poor visual outcome, even after the resolution of the intraretinal fluid. Autofluorescence also helps in the assessment of diabetic retinal pigment epitheliopathy and choroidopathy. Fundus autofluorescence is an evolving technology that will assist in gaining further insight into the pathophysiology of diabetic retinopathy and allow for a more comprehensive evaluation of these patients. Full article

Background: Drusen and drusenoid deposits are a hallmark of age-related macular degeneration (AMD). Nowadays, a multimodal retinal imaging approach enables the detection of these deposits. However, quantitative data on subretinal drusenoid deposits (SDDs) are still missing. Here, we compare the capability of en-face drusen and SDD area detection in eyes with non-exudative AMD using conventional imaging modalities versus Retro mode imaging. We also quantitatively assess the topographic distribution of drusen and SDDs. Methods: In total, 120 eyes of 90 subjects (mean age ± standard deviation = 74.6 ± 8.6 years) were included. Coherent en-face drusen and SDD areas were measured via near-infrared reflectance, green (G-) and blue (B-) fundus autofluorescence (AF), and Retro mode imaging. Drusen phenotypes were classified by correlating en-face drusen areas using structural high-resolution spectral domain optical coherence tomography. The topographic distribution of drusen was analyzed according to a modified ETDRS (Early Treatment of Diabetic Retinopathy Study) grid. Intraclass correlation coefficient (ICC) analysis was applied to determine the inter-reader agreement in the SDD en-face area assessment. Results: The largest coherent en-face drusen area was found using Retro mode imaging with a mean area of 105.2 ± 45.9 mm² (deviated left mode (DL)) and 105.4 ± 45.5 mm² (deviated right mode (DR)). The smallest en-face drusen areas were determined by GAF (50.9 ± 42.6 mm²) and BAF imaging (49.1 ± 42.9 mm²) (p < 0.001). The inter-reader agreement for SDD en-face areas ranged from 0.93 (DR) to 0.70 (BAF). The topographic analysis revealed the highest number of SDDs in the superior peripheral retina, whereas sub-retinal pigment epithelium drusen were mostly found in the perifoveal retina. Retro mode imaging further enabled the detection of the earliest SDD stages. Conclusions: Retro mode imaging allows for a detailed detection of drusen phenotypes. While hundreds/thousands of SDDs can be present in one eye, the impact of SDD number or volume on AMD progression still needs to be evaluated. However, this new imaging modality can add important knowledge on drusen development and the pathophysiology of AMD. Full article

Age-related macular degeneration (AMD) is an age-related disorder that is a global public health problem. The non-enzymatic Maillard reaction results in the formation of advanced glycation end products (AGEs). Accumulation of AGEs in drusen plays a key role in AMD. AGE-reducing drugs may contribute to the prevention and treatment of AGE-related disease. Fructosamine oxidase (FAOD) acts on fructosyl lysine and fructosyl valine. Based upon the published results of fructosamine 3-kinase (FN3K) and FAOD obtained in cataract and presbyopia, we studied ex vivo FAOD treatment as a non-invasive AMD therapy. On glycolaldehyde-treated porcine retinas, FAOD significantly reduced AGE autofluorescence (p = 0.001). FAOD treatment results in a breakdown of AGEs, as evidenced using UV fluorescence, near-infrared microspectroscopy on stained tissue sections of human retina, and gel permeation chromatography. Drusen are accumulations of AGEs that build up between Bruch’s membrane and the retinal pigment epithelium. On microscopy slides of human retina affected by AMD, a significant reduction in drusen surface to 45 ± 21% was observed following FAOD treatment. Enzymatic digestion followed by mass spectrometry of fructose- and glucose-based AGEs (produced in vitro) revealed a broader spectrum of substrates for FAOD, as compared to FN3K, including the following: fructosyllysine, carboxymethyllysine, carboxyethyllysine, and imidazolone. In contrast to FN3K digestion, agmatine (4-aminobutyl-guanidine) was formed following FAOD treatment in vitro. The present study highlights the therapeutic potential of FAOD in AMD by repairing glycation-induced damage. Full article

The Retinal Pigment Epithelium (RPE) plays a prominent role in diseases such as age-related macular degeneration, but imaging individual RPE cells is challenging due to their high absorption and low autofluorescence emission. The RPE lies beneath the highly reflective photoreceptor layer (PR) and contains absorptive pigments, preventing direct backscattered light detection when the PR layer is intact. Here, we used near-infrared autofluorescence adaptive optics scanning laser ophthalmoscopy (NIRAF AOSLO) and transscleral flood imaging (TFI) in the same healthy eyes to cross-validate these approaches. Both methods revealed a consistent RPE mosaic pattern and appeared to reflect a distribution of fluorophores consistent with findings from histological studies. Interestingly, even in apparently healthy RPE, we observed dynamic changes over months, suggesting ongoing cellular activity or alterations in fluorophore distribution. These findings emphasize the value of NIRAF AOSLO and TFI in understanding RPE morphology and dynamics. Full article