Coupling a recurrent neural network to SPAD TCSPC systems for real-time fluorescence lifetime imaging.

Fluorescence lifetime imaging (FLI) has been receiving increased attention in recent years as a powerful diagnostic technique in biological and medical research. However, existing FLI systems often suffer from a tradeoff between processing speed, accuracy, and robustness. Inspired by the concept of Edge Artificial Intelligence (Edge AI), we propose a robust approach that enables fast FLI with no degradation of accuracy. This approach couples a recurrent neural network (RNN), which is trained to estimate the fluorescence lifetime directly from raw timestamps without building histograms, to SPAD TCSPC systems, thereby drastically reducing transfer data volumes and hardware resource utilization, and enabling real-time FLI acquisition. We train two variants of the RNN on a synthetic dataset and compare the results to those obtained using center-of-mass method (CMM) and least squares fitting (LS fitting). Results demonstrate that two RNN variants, gated recurrent unit (GRU) and long short-term memory (LSTM), are comparable to CMM and LS fitting in terms of accuracy, while outperforming them in the presence of background noise by a large margin. To explore the ultimate limits of the approach, we derive the Cramer-Rao lower bound of the measurement, showing that RNN yields lifetime estimations with near-optimal precision. To demonstrate real-time operation, we build a FLI microscope based on an existing SPAD TCSPC system comprising a 32[Formula: see text]32 SPAD sensor named Piccolo. Four quantized GRU cores, capable of processing up to 4 million photons per second, are deployed on the Xilinx Kintex-7 FPGA that controls the Piccolo. Powered by the GRU, the FLI setup can retrieve real-time fluorescence lifetime images at up to 10 frames per second. The proposed FLI system is promising and ideally suited for biomedical applications, including biological imaging, biomedical diagnostics, and fluorescence-assisted surgery, etc.

Lipid Profile Paradox: Investigating Improved Lipid Levels in Diabetic Mellitus Patients with Foot Ulcer Infections-A Prospective Descriptive Study.

Type 2 diabetes mellitus (DM) is a chronic metabolic disorder posing multifaceted challenges to global public health. Among its numerous complications, infected diabetic foot ulcers (IDFUs) represent a particularly debilitating consequence. Beyond cardiovascular implications, there is an emerging understanding of the interconnectedness among IDFUs, neuropathy, atherosclerosis, and dyslipidemia. IDFUs, peripheral neuropathy, and atherosclerosis share common risk factors and mechanistic pathways. The primary objective of this study was to characterize the lipid profiles in DM patients with IDFUs, comparing them with DM patients without foot ulcers, and with a control group of healthy subjects. The secondary objectives included evaluating apolipoprotein E (ApoE) levels across these study groups and comparing lipid profiles within IDFU subgroups. A total of 160 patients were assessed for this study. After applying exclusion criteria, 140 participants were included, divided into three groups: Group IDFU (80 patients with IDFUs), Group DM (32 patients with DM but no foot ulcers), and Group Controls (28 healthy controls). Compared to Group DM, Group IDFU demonstrated lower levels of high-density lipoprotein cholesterol (HDL-C) (30.9 ± 12.6 mg/dL vs. 40.8 ± 16.6 mg/dL, p = 0.002), but improved levels of ApoE (160.9 ± 68.4 mg/dL vs. 197.2 ± 69.6 mg/dL, p = 0.01), triglycerides (TG) (126.9 ± 56.2 mg/dL vs. 165.8 ± 79.0 mg/dL, p = 0.004), low-density lipoprotein cholesterol (LDL-C) (84.2 ± 32.3 mg/dL vs. 92.3 ± 39.3 mg/dL, p = 0.1), and total cholesterol (133.6 ± 43 mg/dL vs. 164.6 ± 44.4 mg/dL, p = 0.002). The IDFU patients exhibit improved lipid profiles, excepting HDL-C, which is unusual because IDFU follows complications related to dyslipidemia for DM patients. Anemia, impaired renal function, and elevated TG levels were identified as biomarkers for mortality among patients with IDFUs. The data suggest that a lower level of HDL-C and an improved lipid profile may indicate a systemic end-stage disease manifestation in DM patients with IDFUs.

Covid-19 and Its Impact on Colorectal Cancer Diagnosis in Romania: A Single-Centered 5-year Retrospective Cohort Study.

Background: Colorectal cancer, 3rd in incidence and 2nd in mortality among cancers worldwide, represents the most common malignant tumor of the digestive tract. In Romania, it is the most frequently diagnosed type of cancer (approximately 0.06% of the population/year). During the COVID-19 pandemic the legislation preventing the SARS-CoV-2 viral transmission impairing access to outpatient healthcare services combined with patients fear of SARS-CoV-2 infection had consequences on the diagnosis and treatment of all other pathologies. Methods: A 5-year retrospective cohort study was conducted in a tertiary hospital in Arad, Romania, and included 1329 newly diagnosed colorectal cancer patients. For statistical analysis, Fisher's exact test was used for categorical data and the unpaired test with Welch's correction for continuous data. Results: The age on diagnosis decreased during the early COVID-19 pandemic to 68.50 (95% CI [67.90 69.11]) years, with the highest percentage (7.41%) of early onset colorectal cancer patients, a steady post-pandemic increase in the percentage of male (52.71% in 2019 to 62.20% in 2022) and urban (54.18% in 2018 to 70.10% in 2022) patients, admitted to the hospital due to an emergency presentation (peaking at 83.95% in 2020) and requiring a longer hospitalization period (10.03 [95% CI (8.76-11.30)] days in 2020 to 8.37 [95% CI (7.44-9.30)] days in 2022). The most common colo-rectal cancer diagnosis of patients in our reference population was malignant neoplasm of the rectum (ICD-10 code C20.0), while the most common complications were peritumoral adherence-related disorder, occlusion, and perforation, encountered in patients with comorbidities such as arterial hypertension, ischemic cardiomyopathy, diabetes mellitus, obesity, and non-alcoholic steatohepatitis. Conclusions: Regional particularities should be analyzed to better target the population at risk and to better direct the necessary healthcare resources towards the reference population, especially during crisis periods similar to the COVID-19 pandemic.

Pentraxin-3 and Other Inflammatory Markers for an Infected Diabetic Foot Ulcer Diagnosis: A Prospective Study.

Strategies have been researched and implemented to reduce the number of people with diabetic foot ulcers (DFUs). One problem is the accurate assessment of DFU severity, which is the main factor in resource allocation and treatment choice. The primary objective of this study was to assess pentraxin-3 as a biomarker of an infected DFU (IDFU), the limb amputation level prognosis, and patient survival. The secondary objectives were to evaluate and compare other markers, including white blood cells (WBCs), C-reactive protein (CRP), the erythrocyte sedimentation rate (ESR), and procalcitonin (PCT), for identifying IDFUs. Over a period of two years, 145 patients were followed; 131 of these were analyzed for this study. Pentraxin-3 was found to be a good predictor of death (p = 0.047). A comparison between IDFUs and DFUs revealed the following differences: PCT had the highest AUROC of 0.91, sensitivity of 93.7, and specificity of 83.3%. CRP had a cutoff value of 226 mg/L, an AUROC of 0.89, a sensitivity of 95.5%, and a specificity of 83.3%. Fibrinogen had an AUROC of 0.87 at a cutoff value of 5.29 g/L, with a good sensitivity and specificity of 85% and 87%, respectively. ESR had a cutoff value of 46 mm/h, an AUROC of 85%, a sensitivity of 83.7%, and a specificity of 83.3%. Pentraxin-3 showed promising results in predicting IDFUs and DFUs, and it served as a marker for the risk of death in IDFU patients during the 6 month follow-up. Other markers, including CRP, PCT, ESR, and fibrinogen, were more effective in differentiating between IDFUs and DFUs.

Massively parallel, real-time multispeckle diffuse correlation spectroscopy using a 500 × 500 SPAD camera.

Diffuse correlation spectroscopy (DCS) is a promising noninvasive technique for monitoring cerebral blood flow and measuring cortex functional activation tasks. Taking multiple parallel measurements has been shown to increase sensitivity, but is not easily scalable with discrete optical detectors. Here we show that with a large 500 × 500 SPAD array and an advanced FPGA design, we achieve an SNR gain of almost 500 over single-pixel mDCS performance. The system can also be reconfigured to sacrifice SNR to decrease correlation bin width, with 400 ns resolution being demonstrated over 8000 pixels.

The importance of CA 72-4 and CA 19-9 dosing in gastric cancer.

Serological analysis of tumor markers has emerged as a non-invasive method for monitoring cancer patients, including tumor recurrence and response to treatment. Tumor markers have the potential to aid in both the diagnosis and prognosis of cancer, but their most important role currently lies in the monitoring of tumor progression. Tumor markers can also provide valuable information on treatment effectiveness, with changes in plasma values indicating tumor regression or progression. This research aimed to investigate the correlation between the serum detection values of three tumor markers - CEA, CA 19-9, and CA 72-4 - and their utility in the diagnosis and prognosis of patients with gastric cancer. The study seeks to uncover the relationship between these tumor markers and the evolution of gastric cancer, providing insights into their potential use in clinical practice.

Clinical significance of tumor necrosis factor-alpha and carcinoembryonic antigen in gastric cancer.

Tumour necrosis factor (TNF)-α plays an important role in inflammatory, infectious, and tumor processes, and it is closely related to the early stages of gastric cancer. It is a pro-inflammatory cytokine, produced not only by macrophages and monocytes but also by the lymphocytes, mast cells, neutrophils, keratinocytes, smooth muscle cells, and some tumor cell lines. Large amounts of TNF are released upon contact of macrophages, CD4 + T lymphocytes, and natural killer (NK) cells with lipopolysaccharides, bacterial products, and interleukin 1. TNF-alpha inducing protein (Tipa) is a unique carcinogenic factor of Helicobacter pylori, secreted into culture broth. The biological activities of TNF alpha and deletion mutant were studied. TNF alpha protein specifically binds to cell-surface nucleolin and then enters the gastric cancer cells, where TNF-a and chemokine gene expressions are induced by NF-jB activation. Nucleolin localizes on the surface of gastric cancer cells, and interaction between TNF alpha and cell-surface nucleolin causes a cancer-oriented microenvironment that increases the risk of gastric cancer. This paper discusses a mechanism of gastric cancer development and the clinical significance of tumor necrosis-alpha and carcinoembryonic antigen in gastric cancer.

Esophageal ulcer associated with mild hemophilia A: case report.

In this paper, we present the case of a 68-year-old male with personal medical history of coagulopathy issues, who presented to our Emergency Room (Emergency County Hospital, Arad, Romania) with bleeding of the superior tract of the digestive system; the case was difficult to manage, thus warranting the intervention of the Department of Gastroenterology. Endoscopy was performed to localize the site of bleeding and to stop the hemorrhage. This procedure was not successful. The patient was transferred to our Intensive Care Unit where different medications, such as proton pump inhibitor, hemostatic agent and prokinetic drugs were administered. Unfortunately, our attempt to stop bleeding failed; this led us to expand our investigation. We focused on a possible hemophilia as the cause of bleeding, which was confirmed as hemophilia A through the coagulometry test after a period of three days. Patient medical history and coagulation test led us to believe that this is a very rare case of a mild hemophilia A. Finally, the correction of Factor VIII deficiency and repeated endoscopic hemostasis clip was able to stop patients bleeding and ensured a favorable clinical evolution of the patient.

Sarcomatoid renal cell carcinoma with clear cells and eosinophilia: a case report and short review of the literature.

Sarcomatoid renal cell carcinoma (SRCC) is an aggressive form of de-differentiated renal cell carcinoma. We report a case of a 79-year-old male who presented himself to the Department of Emergency complaining of macroscopic hematuria for the last two days and a back pain located in the lumbar region persisting for around a month; there were no major changes in the initial laboratory tests. Abdominal ultrasonography identified a renal mass located in the lower pole of the left kidney. The computed tomography (CT) scan with iodine-based contrast revealed the left kidney had a complete deletion of corticomedullary differentiation and a large renal mass located in the lower pole with inhomogeneous iodophilia, which measured around about 15 cm in transversal diameter and 13.6 cm in craniocaudal diameter. Nephrectomy of the left kidney was performed. Histopathological and immunochemistry tests diagnosed a SRCC with clear cells and eosinophilia. We present these findings along with a short review of the literature.

Wide-field time-gated SPAD imager for phasor-based FLIM applications.

We describe the performance of a new wide area time-gated single-photon avalanche diode (SPAD) array for phasor-FLIM, exploring the effect of gate length, gate number and signal intensity on the measured lifetime accuracy and precision. We conclude that the detector functions essentially as an ideal shot noise limited sensor and is capable of video rate FLIM measurement. The phasor approach used in this work appears ideally suited to handle the large amount of data generated by this type of very large sensor (512 × 512 pixels), even in the case of small number of gates and limited photon budget.

Fluorescence lifetime imaging with a single-photon SPAD array using long overlapping gates: an experimental and theoretical study.

Developing large arrays of single-photon avalanche diodes (SPADs) with on-chip time-correlated single-photon counting (TCSPC) capabilities continues to be a difficult task due to stringent silicon real estate constraints, high data rates and system complexity. As an alternative to TCSPC, time-gated architectures have been proposed, where the numbers of photons detected within different time gates are used as a replacement to the usual time-resolved luminescence decay. However, because of technological limitations, the minimum gate length implement is on the order of nanoseconds, longer than most fluorophore lifetimes of interest. However, recent FLIM measurements have shown that it is mainly the gate step and rise/fall time, rather than its length, which determine lifetime resolution. In addition, the large number of photons captured by longer gates results in higher SNR. In this paper, we study the effects of using long, overlapping gates on lifetime extraction by phasor analysis, using a recently developed 512×512 time-gated SPAD array. The experiments used Cy3B, Rhodamine 6G and Atto550 dyes as test samples. The gate window length was varied between 11.3 ns and 23 ns while the gate step was varied between 17.86 ps and 3 ns. We validated the results with a standard TCSPC setup and investigated the case of multi-exponential samples through simulations. Results indicate that lifetime extraction is not degraded by the use of longer gates, nor is the ability to resolve multi-exponential decays.

Widefield High Frame Rate Single-Photon SPAD Imagers for SPIM-FCS.

Photon-counting sensors based on standard complementary metal-oxide-semiconductor single-photon avalanche diodes (SPADs) represent an emerging class of imagers that enable the counting and/or timing of single photons at zero readout noise (better than high-speed electron-multiplying charge-coupling devices) and over large arrays. They have seen substantial progress over the last 15 years, increasing their spatial resolution, timing accuracy, and sensitivity while reducing spurious signals such as afterpulsing and dark counts. They are increasingly being applied for time-resolved applications with the added advantage of enabling real-time options such as autocorrelation. We report in this study on the use of such a state-of-the-art 512 × 128 SPAD array, capable of a time resolution of 10-5-10-6 s for full frames while retaining acceptable photosensitivity thanks to the use of dedicated microlenses, in a selective plane illumination-fluorescence correlation spectroscopy setup. The latter allows us to perform thousands of fluorescence-correlation spectroscopy measurements simultaneously in a two-dimensional slice of the sample. This high-speed SPAD imager enables the measurement of molecular motion of small fluorescent particles such as single chemical dye molecules. Inhomogeneities in the molecular detection efficiency were compensated for by means of a global fit of the auto- and cross-correlation curves, which also made a calibration-free measurement of various samples possible. The afterpulsing effect could also be mitigated, making the measurement of the diffusion of Alexa-488 possible, and the overall result quality was further improved by spatial binning. The particle concentrations in the focus tend to be overestimated by a factor of 1.7 compared to a confocal setup; a calibration is thus required if absolute concentrations need to be measured. The first high-speed selective plane illumination-fluorescence correlation spectroscopy in vivo measurements to our knowledge were also recorded: although two-component fit models could not be employed because of noise, the diffusion of eGFP oligomers in HeLa cells could be measured. Sensitivity and noise will be further improved in the next generation of SPAD-based widefield sensors, which are currently under testing.

Synchronous gastric tumors - case presentation.

Synchronous gastric tumors, and, especially the presence of an adenocarcinoma and gastrointestinal stromal tumors, are less frequent. We present the case of a 75-year-old patient, with no gastrointestinal pathology in the medical history, who was admitted for marked asthenia, nausea, coffee grounds vomiting, inappetence, dizziness, weight loss and periodical epigastralgias. The clinical and imagistic examinations highlighted an ulcerative, infiltrative, bleeding tumor formation, present on the anterior side and subcardially on the small curvature. During the surgery, there was highlighted a second tumor, whitish, of about 2.5 cm, prominent under the peritoneal serous, of firm consistency and with an adherence to the stomach muscles. For removing the two tumors, there was performed total gastrectomy with esophagus-jejunal termino-lateral anastomosis, with jejunum ansa "in omega". The histopathological and immunohistochemical examinations established that the first tumor was a poorly differentiated carcinoma, and the second was a gastrointestinal stromal tumor. The patient's evolution was a good one, both clinically and biologically, the imagistic examinations performed after six and 12 months highlighting the lack of local relapses and absence of metastases.