Autofluorescence imaging to optimize 5-ALA-induced fluorescence endoscopy of bladder carcinoma

Detection of Canine Urothelial Carcinoma Cells in Urine Using 5-Aminolevulinic Acid

This study aimed to establish a method to detect canine urothelial carcinoma cells in urine using 5-aminolevulinic acid (5-ALA) and to evaluate its diagnostic accuracy. Urine samples were collected from 21 dogs diagnosed with urothelial carcinoma and three urothelial carcinoma cell lines were used. Urine samples obtained from seven healthy dogs were used as controls. Cells in the urine sediment, or urothelial carcinoma cell lines, were cultured with 5-ALA and then observed under a fluorescence microscope. Moreover, we examined the relationship between fluorescence intensity and the presence of metastasis as well as tumor invasion into the bladder wall in cases of urothelial carcinoma. Urine-derived cells from urothelial carcinoma and urothelial carcinoma cell lines showed clearer red fluorescence with the addition of 5-ALA compared to that exhibited by the cells from healthy dogs. The sensitivity and specificity of the diagnosis of urothelial carcinoma were 90% and 86%, respectively. Significant associations were found between fluorescence intensity and tumor metastasis and bladder wall invasion. This study showed that 5-ALA can be used to detect urothelial carcinoma cells in dogs with relatively high diagnostic accuracy. Further, the fluorescence intensity of tumor cells caused by 5-ALA correlated with the clinical condition of urothelial carcinoma cases, which suggested that 5-ALA could be used as a prognostic marker for canine urothelial carcinoma.

Review of successful pathways for regulatory approvals in open-field fluorescence-guided surgery

SIGNIFICANCE

The modern use of fluorescence in surgery came iteratively through new devices and pre-existing imaging agents, with indications that were paved via regulatory approvals and device clearances. These events led to a growing set of surgery subspecialty uses.

AIM

This article outlines the key milestones that initiated commercially marketed systems and agents by highlighting temporal sequences and strategic decisions between them, with the goal of helping to inform future successes.

APPROACH

A review of successful regulatory approvals and the sequences between them was completed for companies that achieved US Food and Drug Administration (FDA) premarket approval or new drug approvals (NDAs) or device clearances in the fields of fluorescent imaging agents, open surgery imaging devices, and their approved medical indications.

RESULTS

Angiography agents, indocyanine green and fluorescein, were approved for human use as absorbing dyes, and this use in retinal imaging was the precursor to lateral translation into tissue perfusion imaging in the last two decades with a growing number of devices. Many FDA cleared devices for open fluorescence-guided surgery used the predicate created by the SPY SP2000 system. This first system was 510(k) cleared for angiography imaging with a unique split predicate from x-ray imaging of vasculature and retinal fluorescence angiography. Since that time, the lateral spread of open surgery devices being cleared for new indications has been occurring with a growth of adoption in surgical subspecialties. Growth into new surgical subspecialties has been achieved by leveraging different NDAs and clearances between indications, such that medical uses have broadened over time.

CONCLUSIONS

Key decisions made by developers to advance specific device clearances and NDAs have been based upon existing optical fluorescent agents. The historical lessons and regulatory trends in newer indications and contrast agents can help the field evolve via successful investment in new systems and applications.

Topical application of Photofrin® for photodynamic diagnosis of malignant cutaneous neoplasms

OBJECTIVES

The prognosis of patients suffering from malignant cutaneous neoplasms can be improved by early diagnosis. Exact demarcation of tumor margins could contribute to optimum results in surgical excision and reconstruction. The purpose of our study is to evaluate Photofrin^® with a new diagnostic procedure, photodynamic diagnosis (PDD), for the detection of Bowen's disease (squamous cell carcinoma (SCC) in situ), SCC, and basal cell carcinoma (BCC).

MATERIALS AND METHODS

Sixty patients with cutaneous neoplasms received 2.5 mg/mL Photofrin^® solution topically. After a period of 3 hours, the patients underwent fluorescence illumination (λex = 370-450 nm). Guided by their visible fluorescence, lesions were biopsied at four suspicious sites in each patient. All specimens were analyzed and measured by a pathologist. A quantitative analysis of the fluorescence contrast between the neoplasms and healthy tissue was performed using the Red, Blue, and Green (RGB) Mode and Gray Scale (GS). Statistical analysis was performed by the analysis of variance (ANOVA) test for multiple comparisons.

RESULTS

Of the 60 patients (20 Bowen's disease, 20 SCC, and 20 BCC), malignant neoplasms could be clearly distinguished from adjacent healthy tissue under fluorescence illumination (P < 0.0001). The sensitivity of the malignant neoplasms evaluated using the RGB and GS modes combined showed 92.74% in image results. The specificity of the malignant neoplasms evaluated using the RGB and GS modes combined showed 95.77%.

CONCLUSION

Light-induced fluorescence detection using topical Photofrin^® provides a sensitive, noninvasive technique for the early identification of malignant cutaneous neoplasms.

Chip-on-the-tip compact flexible endoscopic epifluorescence video-microscope for in-vivo imaging in medicine and biomedical research

We demonstrate a 60 mg light video-endomicroscope with a cylindrical shape of the rigid tip of only 1.6 mm diameter and 6.7 mm length. A novel implementation method of the illumination unit in the endomicroscope is presented. It allows for the illumination of the biological sample with fiber-coupled LED light at 455 nm and the imaging of the red-shifted fluorescence light above 500 nm in epi-direction. A large numerical aperture of 0.7 leads to a sub-cellular resolution and yields to high-contrast images within a field of view of 160 μm. A miniaturized chip-on-the-tip CMOS image sensor with more than 150,000 pixels captures the multicolor images at 30 fps. Considering size, plug-and-play capability, optical performance, flexibility and weight, we hence present a probe which sets a new benchmark in the field of epifluorescence endomicroscopes. Several ex-vivo and in-vivo experiments in rodents and humans suggest future application in biomedical fields, especially in the neuroscience community, as well as in medical applications targeting optical biopsies or the detection of cellular anomalies.

The Utility of a Flexible Fluorescence-Cystoscope with a Twin Mode Monitor for the 5-Aminolevulinic Acid-Mediated Photodynamic Diagnosis of Bladder Cancer

OBJECTIVES

To evaluate the diagnostic value of a new photodynamic diagnosis (PDD) system using 5-aminolevulinic acid (ALA) for the diagnosis of bladder tumors. To validate whether false-positive findings caused by tangent effects in PDD can be resolved, we compared diagnostic accuracies between the new PDD system and a conventional PDD system.

PATIENTS AND METHODS

Among 30 transurethral bladder biopsies, 15 cases received ALA-PDD using rigid fluorescence cystoscopy (conventional PDD system), and flexible fluorescence cystoscopy with a twin mode monitor (new PDD system) was used in a separate set of 15 cases. To evaluated the usefulness of ALA-PDD, diagnostic accuracies were retrospectively compared between the conventional PDD system and the new PDD system.

RESULTS

Of 207 specimens from 30 cases, we obtained 110 specimens using the conventional PDD system and 97 specimens using the new PDD system. Of these samples, we selected 30 distal bladder specimens each from both the conventional PDD system and the new PDD system. The overall sensitivity, specificity and false-positive rate for the new PDD system were 100%, 82.6%, and 17.4%, respectively. Those of the conventional PDD system were 83.3%, 66.2% and 33.8%, respectively. The overall false-positive rate of the new PDD system improved to 16.4% when compared with the conventional PDD system. Furthermore, the false-positive rate of the new PDD system in distal bladder samples improved to 11.8%. The overall AUC of the new PDD system was significantly greater compared with that of the conventional PDD system (P<0.05). We obtained similar significant results in the distal bladder samples (P<0.05). All procedures were well tolerated by all patients without any severe adverse events.

CONCLUSION

Flexible cystoscopy had a significantly higher specificity and improved incidence of tangent effects when compared with conventional methods. This preliminary study suggests that the new PDD system using 5-aminolevulinic acid may be more useful than the conventional PDD system.

Is photodynamic diagnosis ready for introduction in urological clinical practice?

The aim of this review is to provide an up-to-date review of the available literature on photodynamic diagnosis (PDD) for nonmuscle-invasive bladder cancer, to present the technique in a comprehensive approach and, finally, to discuss the relevance of PDD in clinical practice in terms of indications, outcomes and its development trend. A literature search was conducted up to July 2012, using MEDLINE and EMBASE via Ovid databases to identify published studies on PDD for nonmuscle-invasive bladder cancer. Only English-language and human-based full manuscripts that reported on case series and studies with >40 participants, concerning clinical evidence of the technique, its efficacy and safety data were included. Evidence showed that PDD significantly improves detection of bladder cancer compared with standard white-light cystoscopy, having proven to be more effective for the diagnosis of carcinoma in situ. This condition seems to facilitate more complete resections, resulting in a lower residual tumor rate, which, in turn consecutively leads to higher recurrence-free survival rates. The literature search demonstrated that for mid- and long-term follow-up, PDD showed acceptable outcomes in terms of tumor detection, as well as lower residual tumor and lower recurrence rates compared with white-light cystoscopy. It has proven to be safe and well tolerated; the major limitations of PDD are its low specificity and elevated costs.

Fluorescence guidance in urologic surgery

PURPOSE OF REVIEW

Fluorescent tracers can provide anatomical and functional information without altering the visual surgical field. Despite the advances that are being made in tracer development, only a few fluorescent tracers are available for urological interventions.

RECENT FINDINGS

Protoporphyrin IX, hypericin, fluorescein, and indocyanine green were shown to facilitate surgical resection in various ways. Hybrid imaging agents, combining radio and fluorescent labels, have shown improved integration between preoperative and intraoperative imaging. With the rise of surgical fluorescence guidance, various camera systems have been developed that are tailored for optimal detection of the fluorochromes of interest.

SUMMARY

In this review, the basics of fluorescence-guided surgery, including tracer and hardware requirements are discussed.

Photodynamic diagnosis in urology: state-of-the-art

OBJECTIVES

To provide an overview on the methodology and clinical relevance of fluorescence diagnosis with exogenous fluorochromes or fluorochrome prodrugs in urology.

METHODS

The methodology is summarised on the basis of our experience and the relevant literature. Clinical results and perspectives are reported and concluded after we scanned and evaluated sources from PubMed. Search items were "aminolev*" or "hypericin" or "photodyn*" or "porphyrin" or "fluorescence" or "autofluorescence" and "bladder" or "prostate" or "kidney" or "peni*" or "condylo*". Some literature was also obtained from journals not indexed.

RESULTS

A large number of clinical trials have shown that photodynamic diagnosis (PDD) improves the ability to detect inconspicuous urothelial carcinoma of the bladder. Fluorescence diagnosis has recently been approved in Europe for the detection of bladder cancer after instillation of a hexaminolevulinate (Hexvix) solution. PDD is recommended by the European Association of Urology for the diagnosis of carcinoma in situ of the bladder. To date, the major weakness of PDD for the detection of bladder cancer is its relatively low specificity. Initial results with PDD for the detection of penile carcinoma, prostate cancer, kidney tumours, and urethral condylomata are promising.

CONCLUSIONS

To determine the actual impact of PDD on recurrence and progression rates of bladder cancer, further long-term observational studies are necessary. These studies also will clarify whether PDD is cost efficient.

Subnanosecond-resolution phase-resolved fluorescence imaging technique for biomedical applications

Characterization of fluorescence emissions from cells often leads to conclusive results in the early detection of cellular abnormalities. Cellular abnormalities can be characterized by their difference in the fluorescence lifetime, which may be less than nanoseconds. A sensitive frequency domain technique, also called a phase-resolved fluorescence imaging technique, is proposed in which fluorescence emissions at the same wavelengths can more effectively be separated with subnanosecond resolution in their lifetime difference. The system configuration is optimized by incorporating even-step phase shifting in the homodyne-assisted signal-processing concept along with the phase-resolved fluorescence technique to eliminate the dc offsets of emission. Experiments are carried out with simulated samples composed of two fluorescence emissions of the same wavelength but with different lifetime values. Suppression of either of the fluorescence emissions by selective imaging of the other validates the superiority of the proposed technique. Hence, this technique can potentially be applied in the early detection of cellular abnormalities.

Topical application of photofrin for photodynamic diagnosis of oral neoplasms

BACKGROUND

The prognosis of patients with oral cancer can be improved by early diagnosis. Exact demarcation of tumor margins could contribute to optimum results in surgical excision and reconstruction. Therefore, the purpose of this study was to evaluate Photofrin (Quadra Logic Technologics, Inc., Vancouver, British Columbia, Canada) with protoporphyrin IX fluorescence as a new diagnostic procedure: photodynamic diagnosis for the detection of hyperplastic and malignant changes in oral tissue.

METHODS

Twenty patients with oral neoplasms received 2.5 mg/ml Photofrin solution topically. After a period of 3 hours, the patients underwent fluorescence illumination (lambdaex = 370 to 450 nm). Guided by their visible fluorescence, lesions were biopsied at four suspicious sites for each patient. All specimens were analyzed and measured by a pathologist. A quantitative analysis of the fluorescence contrast between the neoplastic and healthy tissue was performed using the red, green, and blue mode and the gray scale mode. Statistical analysis was performed by means of the analysis of variance test for multiple comparisons.

RESULTS

The sensitivity of the neoplastic tissue evaluated using the red, green, and blue and the gray scale modes combined was 92.45 percent in the macroscopic study and 93.75 percent in the microscopic study. The specificity of the neoplastic tissue evaluated using the red, green, and blue and gray scale modes combined was 95.65 percent in the macroscopic study and 97.50 percent in the microscopic study. Five patients (25 percent) displayed hyperkeratosis, nine (45 percent) displayed squamous hyperplasia, and six (30 percent) displayed squamous cell carcinoma. It is likely that Photofrin induced the visible red fluorescence. Some fluorescence could be detected in the surrounding healthy tissue. The intensity of the light was much lower than that from the lesions. The difference between healthy tissue and the lesions as a group was statistically significant.

CONCLUSIONS

Light-induced fluorescence detection using topical Photofrin provides a sensitive, noninvasive technique for the early identification of malignant neoplasms in the oral cavity. Further study by the authors will evaluate fluorescence-guided photodynamic therapy for oral cancers in early stages.

Spectral analysis of laser-induced ultraweak delayed luminescence in cultured normal and tumor human cells: temperature dependence

The emission spectrum of ultraviolet A laser induced ultraweak delayed luminescence in cell cultures of mammalian cells depended on the temperature during irradiation and photonic measurements. A new method using a sophisticated photomultiplier system was developed in order to find differences between normal and tumor cells. The maximal peak of the emitted light for cultures measured at low temperature of 10 degrees C was near 510 nm in the green visible region while following irradiation at 32 degrees C this maximum was shifted to yellow-orange at 570 nm both in normal and melanoma cells. Overall, this ultraweak photonic model of cultured cells provides to be a new and powerful non-invasive tool for developing new strategies in skin cancer detection.

Formulation and implementation of a phase-resolved fluorescence technique for latent-fingerprint imaging: theoretical and experimental analysis

A theoretical and experimental study of the imaging of latent fingerprints by a phase-resolved fluorescence technique along with associated signal-processing analysis is described. The system configuration is optimized by incorporation of a novel approach of homodyne-assisted even-step phase shifting in a signal-processing concept. The excitation laser source and gain of the detection device, which are modulated at megahertz frequency followed by sensitive signal-processing concepts, are employed to separate the fingerprint fluorescence from background fluorescence. Experiments are carried out with fingerprints deposited upon different types of substrate surfaces. Later, a quantitative image-quality assessment is carried out, which confirms the improvement in the quality of the phase-resolved fingerprint image. Imaging of older fingerprints with better contrast is also carried out with the proposed novel technique.

Miniaturized Multichannel Near Infrared Endoscope for Mouse Imaging

We describe the design and construction of a miniaturized multichannel near infrared (NIR) endoscopic imaging system developed for high-resolution imaging of mice. The device allows for simultaneous real-time video images in white light and two independent NIR channels. Testing demonstrated independent acquisition of nanomolar concentrations of fluorochromes Cy5.5 and Cy7. Cross-talk between the NIR channels, partially a result of broad tails in the spectra of commonly used organic fluorochromes, was assessed, modeled for the linear range of the concentration/signal intensity function, and compensated. The calculated compensation was 5.5% and 22% of the total signal intensity in the two channels NIR700 and NIR780, respectively, at equal concentrations of the two fluorochromes. Using a mouse model of colonic adenomatosis, we show that both perfusion and protease activity can be detected simultaneously, independently, and repeatedly in live mice. The developed device should be useful for in vivo imaging of diverse molecular targets.

Optimal excitation-emission wavelengths for autofluorescence diagnosis of bladder tumors

Tissue autofluorescence depends on endogenous fluorophores in the tissue, which undergo a change associated with malignant transformation. This change can be detected as an alteration in the spectral profile and intensity of autofluorescence. Our purpose was to determine the optimal excitation and emission wavelengths for autofluorescence diagnosis of bladder cancer. A total of 52 bladder tissue specimens were obtained from 25 patients undergoing mucosal biopsies or surgical resections of bladder tumors. Light-induced autofluorescence measurements were performed to study the spectroscopic differences between normal and malignant bladder tissue. Fluorescence excitation wavelengths varying from 220 to 500 nm were used to induce tissue autofluorescence, and emission spectra were measured in the 280-700 nm range. These spectra were then combined to construct 2-dimensional fluorescence excitation-emission matrices (EEMs). Significant changes in fluorescence intensity of EEMs were observed between normal and tumor bladder tissues, the most marked differences being at the excitation wavelengths of 280 and 330 nm. The diagnostic algorithm based on the combination of the fluorescence peak intensity ratios of I(350)/I(470) at 280 nm excitation and I(390)/I(470) at 330 nm excitation yielded a sensitivity of 100% [95% confidence interval (CI) 0.95-1.0] and specificity of 100% (95% CI 0.90-1.0). The results of the present fluorescence EEM study demonstrate that autofluorescence spectroscopy can distinguish malignant from normal bladder tissue and that excitation wavelengths of 280 and 330 nm are the most significant for differentiation between normal and malignant bladder mucosae with a high degree of diagnostic accuracy.

Detection of squamous cell carcinomas and pre-cancerous lesions in the oral cavity by quantification of 5-aminolevulinic acid induced fluorescence endoscopic images

BACKGROUND AND OBJECTIVES

Studies of 5-aminolevulinic acid-induced protoporphyrin IX fluorescence have shown a sensitivity of 95-100% for oral cancer diagnosis, but the specificity is only about 50-60%. Here, we explore the applicability of quantifying PPIX fluorescence images to improve the diagnostic specificity and detect early oral lesions.

STUDY DESIGN/MATERIALS AND METHODS

PPIX Fluorescence endoscopy and imaging were performed on 28 patients with a known or suspected premalignant or malignant oral cavity lesion. A total of 70 biopsies were taken from the tissue sites imaged for histological analysis. The red-to-blue and red-to-green intensity ratios were calculated from the fluorescence images to correlate with histology.

RESULTS

Suspicious lesions display bright reddish fluorescence, while normal mucosas exhibit blue color background in the fluorescence images. The red-to-blue and red-to-green intensity ratios of malignant tissues are larger than those of benign tissues. Combining the two ratio diagnostic algorithms yields a sensitivity and specificity of 95% and 97%, respectively, exceeding each diagnostic algorithm alone for discriminating malignant tissue from benign tissue.

CONCLUSIONS

Quantifying PPIX fluorescence endoscopic images combined with the ratio diagnostic algorithms developed in this study has the potential to significantly improve the noninvasive diagnosis of oral cavity lesions in vivo.