Autofluorescence Imaging Research Articles

Utilising Hyperspectral Autofluorescence Imaging in the Objective Assessment of Disease State and Pain in Patients with Rheumatoid Arthritis

Rheumatoid Arthritis (RA) is a chronic inflammatory disease resulting in joint swelling and pain. Treatment options can be reliant on disease activity scores (DAS) incorporating patient global assessments, which are quantified via visual analogue scales (VAS). VAS can be subjective and not necessarily align with clinical symptoms, such as inflammation, resulting in a disconnect between the patient’s and practitioners’ experience. The development of more objective assessments of pain would enable a more targeted and personalised management of pain within individuals with RA and have the potential to improve the reliability of assessments in research. Using emerging light-based hyperspectral autofluorescence imaging (HAI) technology, we aimed to objectively differentiate disease and pain states based on the analysis of synovial tissue (ST) samples from RA patients. In total, 22 individuals with RA were dichotomised using the DAS in 28-joint counts (DAS-28) into an inactive (IA) or active disease (active-RA) group and then three sub-levels of pain (low, mid, high) based on VAS. HAI was performed on ST sections to identify and quantify the most prominent fluorophores. HAI fluorophore analysis revealed a distinct separation between the IA-RA and active-RA mid-VAS cohort, successfully determining disease state. Additionally, the separation between active-RA Mid-VAS and active RA High-VAS cohort suggests that HAI could be used to objectively separate individuals based on pain severity.

Comparison of Geographic Atrophy Measurements Between Blue-Light Heidelberg Standard Field and Green-Light Optos Ultrawide Field Autofluorescence.

This study compared geographic atrophy (GA) measurements in the macula using standard 30° field and ultrawide field (UWF) fundus autofluorescence (FAF) imaging. Participants from Age-Related Eye Disease Study 2 (AREDS2) and Optos PEripheral RetinA (OPERA) studies with GA were included for comparison between standard field FAF with Heidelberg Spectralis and Optos 200Tx UWF FAF. Two time points 5years apart were evaluated. GA area (mm2) was recorded in the macular area for both imaging types and in the peripheral field for UWF. Of 102 paired images (73 subjects), the mean (SD) baseline GA area was 5.32 (6.36)mm2 with standard and 4.79 (5.87)mm2 with UWF FAF (P < 0.001). The mean difference between the two modalities was 0.52mm2 (95% confidence interval, -2.41 to 1.37). Progression of GA in 25 eyes over 5years showed a median annual growth rate of 1.28mm2 (range, 0.02 to 4.7) for standard and 1.34mm2 (range, 0.04 to 5.3) for UWF FAF (P = 0.49). The measurement of GA is larger on standard than on UWF FAF imaging. The observed difference may be due to image averaging and the use of blue versus green FAF. Similar GA progression with standard and UWF FAF suggests either may be used longitudinally, although not interchangeably. Further investigation is required with updated UWF technology. With the increasing adoption of UWF imaging modalities, this study suggests that Optos UWF FAF may be used longitudinally as an alternative to standard field FAF to monitor GA.

Quantification of Fundus Autofluorescence Features in a Molecularly Characterized Cohort of More Than 3500 Inherited Retinal Disease Patients from the United Kingdom

PurposeTo quantify relevant fundus autofluorescence (FAF) image features cross-sectionally and longitudinally in a large cohort of patients with inherited retinal diseases (IRDs). DesignRetrospective study of imaging data (55-degree blue-light FAF, Heidelberg Spectralis) . ParticipantsPatients with a clinical and molecularly confirmed diagnosis of IRD who have undergone 55-degree FAF imaging at Moorfields Eye Hospital (MEH) and the Royal Liverpool Hospital (RLH) between 2004 and 2019. MethodsFive FAF features of interest were defined: vessels, optic disc, perimacular ring of increased signal (ring), relative hypo-autofluorescence (hypo-AF) and hyper-autofluorescence (hyper-AF). Features were manually annotated by six graders in a subset of patients based on a defined grading protocol to produce segmentation masks to train an AI model, AIRDetect, which was then applied to the entire imaging dataset. Main Outcome MeasuresQuantitative FAF imaging features including area in mm2 and vessel metrics, were analysed cross-sectionally by gene and age, and longitudinally to determine rate of progression. AIRDetect feature segmentation and detection were validated with Dice score and precision/recall, respectively. ResultsA total of 45,749 FAF images from 3,606 IRD patients from MEH covering 170 genes were automatically segmented using AIRDetect. Model-grader Dice scores for disc, hypo-AF, hyper-AF, ring and vessels were respectively 0.86, 0.72, 0.69, 0.68 and 0.65. Across patients within our cohort at presentation, the five genes with the largest hypo-AF areas were CHM, ABCC6, RDH12, ABCA4, and RPE65, with mean per-patient areas of 43.72, 29.57, 20.07, 19.65, and 16.92 mm2. The five genes with the largest hyper-AF areas were BEST1, CDH23, NR2E3, MYO7A, and RDH12, with mean areas of 0.50, 047, 0.44, 0.38, and 0.33 mm2 respectively. The five genes with largest ring areas were NR2E3, CDH23, CRX, EYS and PDE6B, with mean areas of 3.60, 2.90, 2.89, 2.56, and 2.20 mm2. Vessel density was found to be highest in EFEMP1, BEST1, TIMP3, RS1, and PRPH2 (11.0%, 10.4%, 10.1%, 10.1%, 9.2%) and was lower in Retinitis Pigmentosa (RP) and Leber Congenital Amaurosis genes. Longitudinal analysis of decreasing ring area in four RP genes (RPGR, USH2A, RHO, EYS) found EYS to be the fastest progressor at -0.18 mm2/year. ConclusionsWe have conducted the first large-scale cross-sectional and longitudinal quantitative analysis of FAF features across a diverse range of IRDs using a novel AI approach.

Use of autofluorescent stomatoscopy in the diagnostic algorithm for oral mucosal and vermilion border lesions in adolescents

Relevance. There is currently significant interest in studying the prevalence of diseases affecting the oral mucosa and lip vermilion border in adolescents. A promising approach in this field is the use of modern non-invasive optical technologies, which not only offer additional insights into the patient's oral health status but also enhance their compliance.Materials and methods. A total of 71 adolescents (9th to 11th grade students) aged 15 to 17 years (mean age — 16.2 ± 0.8 years) were examined. The oral mucosa and lip vermilion border were assessed for abnormalities under natural light and through endogenous fluorescence using autofluorescent stomatoscopy. Various optical filters were applied, and clinical images were compared with autofluorescent images. A visual analog scale was used to assess the clarity of the diagnostic test results for the participant. Recommendations were provided, and treatment was prescribed according to the established diagnoses.Results. Oral mucosal lesions and lesions of the lip vermilion border were observed in 45% of cases, all of benign origin, without visible changes to the naked eye or pain. The most frequently diagnosed lesions were morsicatio buccarum and chapped lips. Distinct autofluorescent characteristics of the identified lesions were observed and documented. Participant-reported feedback was positive in 100% of cases during autofluorescent stomatoscopy. The mean score for the clarity of diagnostic results, assessed using the visual analog scale, was 9.3±0.12, indicating a high level of diagnostic visibility.Conclusion. Implementing a qualified clinical approach focused on preventing oral diseases in adolescent patients is recommended with the use of autofluorescent stomatoscopy. This technique not only offers real-time insights into the patient’s oral health status but also actively engages young patients, increasing their motivation to maintain good oral health.

Multimodal Optical Imaging of Ex Vivo Fallopian Tubes to Distinguish Early and Occult Tubo-Ovarian Cancers

Background: There are currently no effective screening measures to detect early or occult tubo-ovarian cancers, resulting in late-stage detection and high mortality. This work explores whether an optical imaging catheter can detect early-stage tubo-ovarian cancers or precursor lesions where they originate in the fallopian tubes. Methods: This device collects co-registered optical coherence tomography (OCT) and autofluorescence imaging (AFI). OCT provides three-dimensional assessment of underlying tissue structures; autofluorescence imaging provides functional contrast of endogenous fluorophores. Ex vivo fallopian tubes (n = 28; n = 7 cancer patients) are imaged; we present methods for the calculation of and analyze eleven imaging biomarkers related to fluorescence, optical attenuation, and OCT texture for their potential to detect tubo-ovarian cancers and other lesions of interest. Results: We visualize folded plicae, vessel-like structures, tissue layering, hemosiderin deposits, and regions of fibrotic change. High-grade serous ovarian carcinoma appears as reduced autofluorescence paired with homogenous OCT and reduced mean optical attenuation. Specimens containing cancerous lesions demonstrate a significant increase in median autofluorescence intensity and decrease in Shannon entropy compared to specimens with no lesion. Non-cancerous specimens demonstrate an increase in optical attenuation in the fimbriae when compared to the isthmus or the ampulla. Conclusions: We conclude that this approach shows promise and merits further investigation of its diagnostic potential.

Autofluorescence imaging guided needle-type Raman spectroscopy (TNBN-RS) system for breast tumor margin assessment

Autofluorescence imaging guided needle-type Raman spectroscopy (TNBN-RS) system for breast tumor margin assessment

Glutaraldehyde-enhanced autofluorescence as a general tool for 3D morphological imaging.

Routine histochemical techniques are capable of producing vast amount of information from diverse samples types, but these techniques are limited in their ability to generate 3D information. Autofluorescence imaging can be used to analyse samples in 3D but it suffers from weak/low signal intensities. Here, we describe a simple chemical treatment with glutaraldehyde to enhance autofluorescence for 3D fluorescence imaging and to generate detailed morphological images on whole-mount samples. This methodology is straightforward and cost-effective to implement, suitable for a wide range of organisms and sample types. Furthermore, it can be readily integrated with standard confocal and fluorescence microscopes for analysis. This approach has the potential to facilitate the analysis of biological 3D structures and research in developmental biology, including studies on model and non-model organisms.

Multispectral Imaging of Collagen, NAD(P)H and Flavin Autofluorescence in Mesenchymal Stem Cells Undergoing Trilineage Differentiation.

Understanding the molecular mechanisms of differentiation is important for regenerative medicine and developmental biology. This study aims to characterise the role of the glycolysis/oxidative phosphorylation balance as a driver of mesenchymal stem cell (MSC) differentiation. Cells were maintained in normal conditions or stimulated towards the MSC trilineage cell types over 21 days. Multispectral imaging of cell autofluorescence was applied as a non-invasive methodology to continuously image cultures in situ. Spectral signals for collagen, NAD(P)H, and flavins were unmixed. MSCs cultured under chondrogenic conditions exhibited increased collagen levels relative to controls. Following osteogenic induction, MSCs showed increased collagen levels relative to controls during the earlier stages of culture; however, control cells increased their collagen levels as they became confluent. MSCs cultured under adipogenic conditions exhibited lower levels of collagen than controls. The redox ratio (RR; NAD(P)H/flavins) immediately decreased during chondrogenesis, with this early effect persisting throughout the culture compared to control cells, which appeared to increase their RR, similar to osteogenesis. Adipogenesis resulted in a small increase in RR on day 2 relative to control cells, followed by a persistent decrease. Chondrogenic and adipogenic differentiation favoured oxidative phosphorylation, whereas osteogenesis and MSC overgrowth resulted in a glycolytic metabolism. Following consideration of these findings, as well as the diverse reports in the literature, it is concluded that neither enhanced oxidative phosphorylation nor glycolysis are fundamental to the canonical modes of differentiation, and researchers should avoid interpreting shifts as indicating differentiation.

The use of autofluorescence stomatoscopy in the algorithm of diagnosing of the oral mucosal abnormalities of patients with tuberculosis infection

AIM. To evaluate the feasibility of using the autofluorescence stomatoscopy in dental examination of patients with tuberculosis infection.MATERIALS AND METHODS. The objects of the study were 75 patients aged 21 to 65 years (average age 47.9±2.1 years), 48 men and 27 women (64% and 36%, respectively) who are at the stages of treatment and reha bilitation of the underlying disease (pulmonary tuberculosis) in a specialized tuberculosis sanatorium. The design of the study included the generally standard stages of a comprehensive dental examination of patients, in which diseases of the oral mucosa and the red border of the lips were additionally detected using autofluorescence stomatoscopy, as well as a laboratory Candida test was carried out. The clinical picture of the diagnosed pathological conditions of the oral mucosa, autofluorescence images and their pathomorphological features were compared. The reports of the examined persons regarding the autofluorescence stomatoscopy were evaluated.RESULTS. It was shown that diseases of the oral mucosa and the red border of the lips in patients with tuberculosis infection are highly common (92%), are found more often in males and differ in the heterogeneity of their structure, which is dominated by candidiasis of the oral mucosa, traumatic lesions and various forms of cheilitis. The features of autofluorescence images of pathological conditions of the oral mucosa of different nature of the origin are marked. Positive feedback from patients after the autofluorescence stomatoscopy was recorded in 100% of cases.CONCLUSIONS. The use of the autofluorescence stomatoscopy in the algorithm of dental examination of patients with tuberculosis infection is appropriate because it allows to implement the principle of oncological alertness among specialists, helps the doctor to obtain additional information about the pathological process in real time and increases the motivation of the examined persons to maintain dental health.

Rheumatic fever and long-term use of benzathine penicillin as possible risk factors for extensive macular atrophy with pseudodrusen in a Brazilian cohort

BackgroundAlthough there has been a large increase in the number of extensive macular atrophy with pseudodrusen (EMAP) cases, the basic aspects of this disease remain unknown. Brazilian patients have a common past history of rheumatic fever (RF) and/or benzathine penicillin (BP) treatment possibly related to the disease. We analyzed how RF and BP might be correlated with EMAP in Brazilian patients.DesignObservational, retrospective, case-control study.MethodsThe databases of three private eye clinics in Brazil were searched for patients with an EMAP-like appearance. Each patient was asked about a previous history of RF and/or long-term use of BP. Patients underwent best-corrected visual acuity (BCVA) measurement, color fundus imaging, fundus autofluorescence (FAF) imaging, optical coherence tomography (OCT) imaging, and electroretinography (ERG). The following characteristics were analyzed: subretinal drusenoid deposits (SDD), pigment mottling, retinal pigment epithelial/basement membrane (RPE/BM) separation, outer retinal or RPE atrophy, and identification of a paving stone-like appearance. The choroidal thickness was measured using enhanced depth imaging OCT. The central atrophic area was measured manually on ultra-wide-field FAF.ResultsA total of 154 eyes of 77 patients (women, 66.2%; mean age, 58.6 years) with EMAP were included; 90.9% of patients were diagnosed with RF; 94.8% had been treated with BP and treatment was started at an average age of 7.3 years (mean duration, 11.8 years). The treatment duration was significant for the area of atrophy (P = 0.027) in which each 1-year increase in treatment duration led to an average reduction of 6.91 mm2 in area. The age at diagnosis of RF was significant (P = 0.026) for SDD. The increase of 1 year in the diagnosis of RF (late disease) led to a reduction of 24% in the chance of central SDD being present. On OCT, 65.5% eyes had SDD and more than 70% had a split RPE/BM and outer retinal or RPE atrophy. The choroidal thickness in patients with EMAP was significantly (P < 0.001) thinner than the control group. The ERG was abnormal in all eyes.ConclusionThese findings may suggest a relation between RF and EMAP in Brazilian patients. Patients with EMAP should be questioned about a history of RF.

Role of fundus autofluorescence imaging in the management of submacular hemorrhage

PurposeTo evaluate the baseline characteristics of fundus autofluorescence (FAF) in patients with submacular hemorrhage (SMH).MethodsThis retrospective study included patients diagnosed with treatment-naive, foveal-involving subretinal hemorrhage (size > 2-disc diameters) of any etiology, presenting between June 2017 and June 2023. Only cases with good-quality color fundus photographs, optical coherence tomography (OCT) scans, and blue-light FAF images at baseline were included. SMH imaging characteristics were documented and correlated with treatment outcomes. A successful treatment outcome was defined as the reduction, displacement or clearance of the SMH from beneath the fovea.ResultsNineteen cases of SMH (13 males, 6 females), ranging from 14 to 85 years, were analyzed. Neovascular age-related macular degeneration (nAMD) was the most common etiology (n = 11, 58%). Baseline visual acuity ranged from 6/9 to counting fingers at ½ meter, with a median presentation time of 7 days from symptom onset (range: 1–57 days). Treatment success was observed in 13 eyes (68%). Hypoautofluoroscence on FAF was significantly associated with SMH resolution (p = 0.021). However, no association was found between treatment success and clinical hemorrhage characteristics (p = 0.222), OCT findings (p = 0.222), or specific treatments (p > 0.05). Hypoautofluoroscence on FAF was the sole predictor of treatment success, as demonstrated by Spearman’s correlation (r = 0.637; p = 0.003) and linear regression analysis (p = 0.003).ConclusionFAF, in conjunction with color fundus photography and OCT, may provide valuable insights for clinicians in formulating treatment strategies for patients with SMH. Hypoautofluoroscence on FAF was a significant predictor of successful SMH resolution in this study.

Secondary Multiple Evanescent White Dot Syndrome in a patient with North Carolina Macular Dystrophy.

To describe a novel case of secondary multiple evanescent white dot syndrome in a patient with North Carolina Macular Dystrophy (NCMD). The patient was evaluated with ultra-widefield color and autofluorescence imaging, fluorescein angiography, and spectral-domain optical coherence tomography. A 43-year-old man with longstanding blurred vision in both eyes acutely developed glare in the right eye after an upper respiratory illness. He had chorioretinal atrophy in both eyes consistent with North Carolina Macular Dystrophy, which was later confirmed by genetic testing. He alsyo had white spots in the macula of the right eye consistent with secondary MEWDS. The diagnosis of secondary MEWDS was confirmed with fundus autofluorescence and fluorescein angiography, as well as a negative infectious workup. His symptoms and the retinal lesions had resolved by 11 weeks and after a short course of oral corticosteroids. Prior studies have suggested a link between disruption of the RPE/Bruch's membrane complex and secondary MEWDS. This report describes the first case of secondary MEWDS after NCMD and provides further support for this association.

PATHWAYS TO GEOGRAPHIC ATROPHY IN NONNEOVASCULAR AGE-RELATED MACULAR DEGENERATION.

To characterize and quantify the precursor lesions of geographic atrophy in eyes with age-related macular degeneration. A retrospective study of eyes with a minimum of 6-month follow-up before developing geographic atrophy. Evaluations included color and autofluorescence imaging, along with spectral-domain optical coherence tomography, employing definitions from the Consensus of Atrophy Meeting Group and Consensus on Neovascular Age-Related Macular Degeneration Nomenclature Study Group. There were 55 eyes of 44 patients, who had a mean age of 81.3 years at onset of atrophy; 35 (63.6%) were female. The mean duration of follow-up before and after the advent of geographic atrophy was 4.9 years and 1.2 years, respectively. Geographic atrophy was preceded by collapse of a druse in 41 eyes (74.5%). Of these, 29 (70.7%) were drusenoid pigment epithelial detachments. Among the eyes with regressing drusen, there were 9 with overlying vitelliform deposit, and all had concurrent subretinal drusenoid deposit; however, 19 of 30 eyes with no vitelliform deposit overlying the druse had concurrent subretinal drusenoid deposit, a difference that was significant ( P < 0.001). Regression of subretinal drusenoid deposit was found in 4 eyes (7.3%), regression of vitelliform deposit associated with subretinal drusenoid deposit in 5 (9.1%), and regression of vitelliform deposit in eyes concurrently harboring drusen was found in 3 (5.4%) and regression of vitelliform deposit alone in 2 (3.6%) at the site of eventual development of geographic atrophy. Geographic atrophy appears to develop from multiple pathways as manifested by the many precursor lesions, all various forms of extracellular deposit, that upon regression, result in a common end-stage appearance.

Deep Learning to Predict the Future Growth of Geographic Atrophy from Fundus Autofluorescence

PurposeThe region of growth (ROG) of geographic atrophy (GA) throughout the macular area has an impact on visual outcomes. Here, we developed multiple deep learning (DL) models to predict the 1-year ROG of GA lesions using fundus autofluorescence (FAF) images. DesignIn this retrospective analysis, 3 types of models were developed using FAF images collected 6 months after baseline to predict the GA lesion area (segmented lesion mask) at 1.5 years, FAF images collected at baseline and 6 months to predict the GA lesion at 1.5 years, and FAF images collected 6 months after baseline to predict the GA lesion at 1 and 1.5 years. The 1-year ROG from the 6-month visit was derived by taking the difference between the GA lesion area (segmented lesion mask) at the 1.5-year and 6-month visits. ParticipantsPatients enrolled in the following lampalizumab clinical trials and prospective observational studies: NCT02247479, NCT02247531, NCT02479386, and NCT02399072. MethodsDatasets of study eyes from 597 patients were split into model training (310), validation (78), and test sets (209), stratified by baseline or initial lesion area, lesion growth rate, foveal involvement, and focality. DL experiments were performed using the 2-dimensional U-Net, whole-lesion and multiclass models were developed. Main Outcome MeasuresThe performance of the models was evaluated by calculating the Dice score, coefficient of determination (R2), and the squared Pearson correlation coefficient (r2) between the true and derived GA lesion 1-year ROG. ResultsThe model using baseline and 6-month FAF images to predict GA lesion enlargement at 1.5 years had the best performance for the derived 1-year ROG. Mean Dice scores were 0.73, 0.68, and 0.70, respectively, in the training, validation, and test sets. The R2 (0.77, 0.53, and 0.79) and r2 (0.83, 0.61, and 0.79) showed similar trends across the 3 sets. ConclusionsThese findings show the potential of using baseline and/or 6-month visit FAF images to predict 1-year GA ROG using a DL approach. This work could potentially help support decision making in clinical trials and more informed treatment decisions in clinical practice.

IMAGING PREDICTORS OF FUNCTIONAL OUTCOMES AFTER RHEGMATOGENOUS RETINAL DETACHMENT REPAIR.

To evaluate the microstructural optical coherence tomography and fundus autofluorescence imaging predictors of visual acuity, metamorphopsia, and aniseikonia following rhegmatogenous retinal detachment repair. This is a multicenter retrospective study of patients with primary rhegmatogenous retinal detachment who underwent repair. Best-corrected visual acuity, metamorphopsia, and aniseikonia were formally tested at 3 months postoperatively. Metamorphopsia and aniseikonia were quantitatively assessed with M-CHARTS and the New Aniseikonia Test, respectively. High-resolution spectral-domain optical coherence tomography and fundus autofluorescence images were obtained at 3 months postoperatively. Images were assessed for discontinuity of the outer retinal bands on optical coherence tomography and retinal displacement detected by retinal vessel printings on fundus autofluorescence by two masked graders with disagreements adjudicated by a third senior masked grader. Multiple linear regression models were used to determine the predictors of postoperative visual acuity, metamorphopsia, and aniseikonia. Six hundred fourteen eyes of 614 patients were included in this study. Regression analysis indicated that significant early postoperative (at 3 months) imaging predictors of visual acuity were discontinuity of the external limiting membrane (P = 0.001) and the presence of retinal vessel printings on fundus autofluorescence (P = 0.033). Discontinuity of interdigitation zone was a significant predictor of metamorphopsia [horizontal metamorphopsia (P =0.004); vertical metamorphopsia (P = 0.056); average of horizontal metamorphopsia + vertical metamorphopsia (P = 0.008)], and presence of retinal vessel printings was a significant predictor of aniseikonia (P = 0.04). Discontinuity of the external limiting membrane and retinal displacement were significant predictors of postoperative visual acuity following rhegmatogenous retinal detachment repair. Discontinuity of the interdigitation zone and retinal displacement were significant predictors of metamorphopsia and aniseikonia, respectively.

Near-Infrared Autofluorescence Signatures of Single- vs Multigland Disease in Primary Hyperparathyroidism

The success of parathyroidectomy depends on accurate intraoperative localization and identification of all diseased glands in parathyroid exploration based on surgeon expertise to prevent persistent hyperparathyroidism. Near-infrared autofluorescence (NIRAF) imaging has recently emerged as a promising adjunctive intraoperative tool for localizing parathyroid glands; however, its potential utility in the assessment of parathyroid glands has yet to be established. To analyze the differences in NIRAF signatures of parathyroid glands in single vs multiple glands in primary hyperparathyroidism (pHPT). This prospective diagnostic study analyzed in vivo NIRAF images of parathyroid glands obtained during parathyroidectomies between November 18, 2019, and December 31, 2023, at a single tertiary referral center. Pixel intensities of the images were measured using third-party software. Patients who underwent parathyroidectomy for sporadic pHPT using a second-generation NIRAF imaging device were included. Patients with multiple endocrine neoplasm disorders were excluded. In vivo NIRAF images obtained during the procedures were analyzed. Near-infrared autofluorescence imaging during parathyroidectomy. The primary outcomes were the autofluorescence intensity and heterogeneity of single adenomas and multigland disease (ie, double adenomas and 3- or 4-gland hyperplasia) in sporadic pHPT. Normalized autofluorescence intensity was calculated by dividing the mean pixel intensity of the parathyroid gland by the background tissue. A heterogeneity index was calculated by dividing the standard deviation by the mean pixel intensity of the gland. The secondary outcome was the visibility of each parathyroid gland on NIRAF imaging before it became apparent to the naked eye during exploration. A total of 1287 in vivo NIRAF images obtained from 377 patients (median [IQR] age, 66 [56-73] years; 299 female [79.3%]) were analyzed. Of all patients, 230 (61.0%) had a single adenoma, 91 (24.1%) had double adenomas, and 56 (14.9%) had 3- or 4-gland hyperplasia. A mean (SD) of 3.4 (1.1) parathyroid glands were identified in the procedures. A comparison of 581 diseased glands (45.1%) and 706 normal glands (54.9%) showed a lower median normalized autofluorescence intensity of 2.09 (95% CI, 1.07-4.01) vs 2.66 (95% CI, 1.43-4.20; effect size = 0.36) and higher heterogeneity index of 0.18 (95% CI, 0.07-0.41) vs 0.11 (95% CI, 0.01-0.27; effect size = 0.45), respectively. Of diseased glands, single adenomas (233 [40.1%]) vs double adenomas (187 [32.2%]) and 3- or 4-gland hyperplasia (161 [27.7%]) had a lower median autofluorescence intensity of 1.92 (95% CI, 1.02-4.44) vs 2.22 (95% CI, 1.10-3.97; effect size = 0.21), respectively. On receiver operating characteristic analysis, the optimal autofluorescence intensity threshold to differentiate between single adenomas vs multigland disease was 2.14, with a sensitivity of 64.4%, specificity of 58.1%, and area under the curve of 0.626. These findings suggest that parathyroid glands in single- vs multigland disease may exhibit different autofluorescence characteristics. Although the effect size was modest, the differences identified should be kept in mind when assessing the parathyroid glands during surgical exploration.

From onset to blindness: a comprehensive analysis of RPGR-associated X-linked retinopathy in a large cohort in China

BackgroundVariants in the RPGR are the leading cause of X-linked retinopathies (XLRPs). Further in-depth investigation is needed to understand the natural history.MethodsReview of all case records, molecular genetic testing results,...

Retinal displacement following direct versus indirect fluid exchange in pars Plana vitrectomy for rhegmatogenous retinal detachment.

To compare the occurrence and characteristics of retinal displacement following direct perfluorocarbon liquid (PFCL)-silicone oil (SO) exchange versus indirect PFCL for air and air for SO exchange methods during pars plana vitrectomy (PPV) in patients with rhegmatogenous retinal detachment (RRD). A comparative case series study was conducted on 58 eyes with recent RRD, undergoing standard three-port PPV with SO tamponade. Fluid exchange was performed using either direct or indirect methods. Postoperatively, a comprehensive ophthalmic examination and fundus autofluorescence (FAF) imaging were conducted at one month. The presence, amount, and direction of retinal displacement were assessed based on FAF imaging and compared between the direct and indirect fluid exchange groups. FAF imaging at one month revealed retinal displacement in 41.4% of eyes in the direct group and 62.1% in the indirect group, with no statistical difference between them (P = 0.537). However, the mean displacement was significantly higher in the indirect group (282.61 ± 110.83 µm) compared to the direct group (220.33 ± 39.67 µm, P = 0.04). The direction of displacement (downward or upward) did not differ significantly between the groups (P = 0.093). While the occurrence and location of postoperative retinal displacement did not significantly differ between direct and indirect fluid exchange methods during PPV for RRD, eyes treated with the direct method exhibited lower mean displacement compared to the indirect method. These findings suggest potential benefits of the direct exchange approach in minimizing retinal displacement following surgery.

Virtual birefringence imaging and histological staining of amyloid deposits in label-free tissue using autofluorescence microscopy and deep learning

Systemic amyloidosis involves the deposition of misfolded proteins in organs/tissues, leading to progressive organ dysfunction and failure. Congo red is the gold-standard chemical stain for visualizing amyloid deposits in tissue, showing birefringence under polarization microscopy. However, Congo red staining is tedious and costly to perform, and prone to false diagnoses due to variations in amyloid amount, staining quality and manual examination of tissue under a polarization microscope. We report virtual birefringence imaging and virtual Congo red staining of label-free human tissue to show that a single neural network can transform autofluorescence images of label-free tissue into brightfield and polarized microscopy images, matching their histochemically stained versions. Blind testing with quantitative metrics and pathologist evaluations on cardiac tissue showed that our virtually stained polarization and brightfield images highlight amyloid patterns in a consistent manner, mitigating challenges due to variations in chemical staining quality and manual imaging processes in the clinical workflow.

Analysis of near-infrared autofluorescence imaging for detection of inadvertently resected parathyroid glands after endoscopic thyroidectomy

BackgroundPreserving parathyroid function during thyroidectomy is crucial, but remains challenging. Real-time near-infrared autofluorescence (NIRAF) aids surgeons in intraoperative parathyroid gland (PTG) identification. However, its role in detecting PTGs unintentionally removed during surgery is unclear. Study designThis prospective study included adult patients undergoing endoscopic thyroidectomy. Surgeons identified and documented PTGs visually. Excised specimens underwent visual inspection and NIRAF imaging (PDE-Neo II). All fluorescent tissues were dissected and pathologically evaluated (reference standard). One scanned image per lobe was chosen to quantify autofluorescence (AF) intensity. ResultsOverall, 95 patients underwent endoscopic thyroidectomies, with NIRAF imaging applied to 152 excised lobes. Of these, 19 lobes displayed a total of 23 spots with increased intensity. 175 specimens were sent for pathological evaluation, and 7 were confirmed to be parathyroid tissue. NIRAF demonstrated 100.0 % sensitivity and 90.5 % specificity for predicting parathyroid tissue, with 30.4 % positive predictive value, 100.0 % negative predictive value of and 90.9 % accuracy. Quantitatively normalized, the AF signal intensity was significantly higher in NIRAF-positive tissues than negative (4.3 vs 1.2 times, p < 0.0001). Additionally, the AF signal intensity in regions pathologically confirmed of parathyroid tissue was higher than non-parathyroid tissue (9.1 vs 2.1 times, p < 0.0001). ConclusionThis study suggests that NIRAF has high sensitivity and specificity for detecting inadvertently resected PTGs after endoscopic thyroidectomy, contributing to preservation efforts. However, NIRAF-positive tissues still require additional confirmation through multiple methods, emphasizing other examinations to verify that they are indeed parathyroid tissues. Further research is warranted to refine NIRAF imaging parameters.