Handheld Reflectance Confocal Microscopy for the Detection of Recurrent Extramammary Paget Disease

The Role of Line-Field Confocal Optical Coherence Tomography in Detecting Extramammary Paget Disease Recurrences: A Pilot Diagnostic Study

Extramammary Paget disease (EMPD) is an uncommon adenocarcinoma of apocrine gland-rich areas, presenting significant diagnostic challenges due to its nonspecific clinical appearance and frequent misidentification as benign, inflammatory skin conditions. Traditional diagnostic methods such as biopsy are invasive and uncomfortable, often required repeatedly due to high recurrence rates. Dermoscopy and non-invasive imaging techniques have been used but provide limited diagnostic accuracy due to their constraints in depth penetration and resolution. Recent advancements in imaging technologies, such as line-field confocal optical coherence tomography (LC-OCT), show promise in enhancing diagnostic precision while minimizing invasive procedures. LC-OCT merges high-resolution imaging with deep penetration capabilities, capturing detailed horizontal and vertical skin images akin to histopathology. This study evaluated the diagnostic performance of LC-OCT in detecting EMPD and its recurrence in 17 clinically suspicious anogenital regions, belonging to six patients. Data were collected prospectively at the patient's bedside by an LC-OCT expert with poor training for EMPD, and, then, reviewed retrospectively by an independent LC-OCT expert with adequate training for EMPD and no concerns about time. The prospective examination yielded 64.7% accuracy (11 true results out of 17 total cases), 71.4% sensitivity (10 true positives out of 14 actual positives), and 33.3% specificity (1 true negative out of 3 actual negatives). The retrospective analysis achieved 94.1% accuracy (16 true results out of 17 total cases), 100% sensitivity (14 true positives out of 14 actual positives), and 66.7% specificity (2 true positives out of 3 actual positives), with the only false positive case being a difficult-to-diagnose concomitant presentation of a lichen sclerosus et atrophicus. Despite the need for specialized training, our results suggest that LC-OCT represents a valuable tool for accurately identifying EMPD and improving its management by reducing unnecessary biopsies. Further studies are needed to standardize its clinical application.

Deep learning-based photodamage reduction on harmonic generation microscope at low-level optical power

The trade-off between high-quality images and cellular health in optical bioimaging is a crucial problem. We demonstrated a deep-learning-based power-enhancement (PE) model in a harmonic generation microscope (HGM), including second harmonic generation (SHG) and third harmonic generation (THG). Our model can predict high-power HGM images from low-power images, greatly reducing the risk of phototoxicity and photodamage. Furthermore, the PE model trained only on normal skin data can also be used to predict abnormal skin data, enabling the dermatopathologist to successfully identify and label cancer cells. The PE model shows potential for in-vivo and ex-vivo HGM imaging.

Case report: The application of neoadjuvant chemoradiotherapy in anal adenocarcinoma combined with perianal Paget disease involving vulvar skin

Anal adenocarcinoma combined with perianal Paget's disease (PPD) involving the vulva is rare, and there is no established standard treatment. We present the case of a 69-year-old woman with symptoms of intermittent hematochezia and perianal discomfort for 7 months. Upon examination, we discovered a plaque-like hard mass on the right posterior wall of the anal canal, which extended to encompass the anus and dentate line. The lesion skin also extended forward from the gluteal groove, involving the bilateral labial area. Colonoscopy revealed an extensive protruding lesion on the dentate line, which was confirmed as anal adenocarcinoma (mrT4N0M0). The presence of Paget's cells in perianal and vulvar skins led to the diagnosis of PPD. The strategy of neoadjuvant chemoradiotherapy (nCRT) followed by radical surgery was then made after multi-disciplinary discuss. The scope and extent of perianal and vulvar disease were significantly diminished after nCRT. The patient underwent laparoscopic abdominoperineal resection and vulvar lesion resection, confirming the diagnosis of anal adenocarcinoma (ypT2N0). No evidence of tumor cells was found in perianal and vulvar skin, indicating a complete response. The patient is regularly monitored without recurrence or metastasis.

Research Techniques Made Simple: Emerging Imaging Technologies for Noninvasive Optical Biopsy of Human Skin

Over the past few years, high-resolution optical imaging technologies such as optical coherence tomography (OCT), reflectance confocal microscopy (RCM), and multiphoton microscopy (MPM) have advanced significantly as new methodologies for clinical research and for real-time detection, diagnosis, and therapy monitoring of skin diseases. Implementation of these technologies into clinical research and practice requires clinicians to have an understanding of their capabilities, benefits, and limitations. This concise review provides insights on the application of OCT, RCM, and MPM for clinical skin imaging through images acquired in vivo from the same lesions. The presented data are limited to pigmented lesions and basal cell carcinoma.

Evidence-Based Clinical Practice Guidelines for Extramammary Paget Disease

IMPORTANCE

Extramammary Paget disease (EMPD) is a frequently recurring malignant neoplasm with metastatic potential that presents in older adults on the genital, perianal, and axillary skin. Extramammary Paget disease can precede or occur along with internal malignant neoplasms.

OBJECTIVE

To develop recommendations for the care of adults with EMPD.

EVIDENCE REVIEW

A systematic review of the literature on EMPD from January 1990 to September 18, 2019, was conducted using MEDLINE, Embase, Web of Science Core Collection, and Cochrane Libraries. Analysis included 483 studies. A multidisciplinary expert panel evaluation of the findings led to the development of clinical care recommendations for EMPD.

FINDINGS

The key findings were as follows: (1) Multiple skin biopsies, including those of any nodular areas, are critical for diagnosis. (2) Malignant neoplasm screening appropriate for age and anatomical site should be performed at baseline to distinguish between primary and secondary EMPD. (3) Routine use of sentinel lymph node biopsy or lymph node dissection is not recommended. (4) For intraepidermal EMPD, surgical and nonsurgical treatments may be used depending on patient and tumor characteristics, although cure rates may be superior with surgical approaches. For invasive EMPD, surgical resection with curative intent is preferred. (5) Patients with unresectable intraepidermal EMPD or patients who are medically unable to undergo surgery may receive nonsurgical treatments, including radiotherapy, imiquimod, photodynamic therapy, carbon dioxide laser therapy, or other modalities. (6) Distant metastatic disease may be treated with chemotherapy or individualized targeted approaches. (7) Close follow-up to monitor for recurrence is recommended for at least the first 5 years.

CONCLUSIONS AND RELEVANCE

Clinical practice guidelines for EMPD provide guidance regarding recommended diagnostic approaches, differentiation between invasive and noninvasive disease, and use of surgical vs nonsurgical treatments. Prospective registries may further improve our understanding of the natural history of the disease in primary vs secondary EMPD, clarify features of high-risk tumors, and identify superior management approaches.

Value of pseudopod sign on high-frequency ultrasound in predicting the pathological invasion of extramammary Paget's disease lesions

BACKGROUND

Vertical invasion of extramammary Paget's disease (EMPD) is associated with poor prognosis. The usual vertical invasion route is directly downward or along the skin appendages. High-frequency ultrasound (HFUS) can be used to measure the EMPD lesion thickness, and visualize the pseudopod extensions due to skin appendage involvement. It is a non-invasive method for evaluating the extent of vertical invasion in EMPD.

OBJECTIVE

To investigate the value of HFUS in predicting the extent of vertical invasion in EMPD.

METHODS

In this retrospective study, 85 patients with EMPD were divided into two groups based on the pathology: invasive EMPD (iEMPD) group (n = 13) and in situ EMPD group (n = 72). The clinical and HFUS features of both the groups were analyzed. The different types of pseudopodia morphology on HFUS were as follows: no pseudopodia, irregular bottom, small sphere, short strip, long strip, vase shape, and nodular convex. These were further stratified into low-risk and high-risk levels.

RESULTS

The clinical features were comparable between the two groups (P > .05). There were significant differences between the two groups in the HFUS features (lesion thickness, lesion shape, bottom shape, layer involvement, pseudopodia morphology, and color Doppler blood flow signal; all P < .05). The distribution of the pseudopodia morphology types in the in situ EMPD and iEMPD groups, was as follows: no pseudopodia, 30/72 and 0/13; irregular bottom, 5/72 and 0/13; small sphere, 5/72 and 0/13; short strip, 21/72 and 0/13; long strip, 8/72 and 3/13; vase shape, 3/72 and 3/13; and nodular convex, 0/72 and 7/13 (P < .05 for all). The sensitivity and specificity of high-risk pseudopodia in identifying iEMPD were 100% and 84.7%, respectively.

CONCLUSIONS

HFUS provides morphological information regarding EMPD lesions. Risk stratification for pseudopodia can help to distinguish between iEMPD and in situ EMPD lesions.

Assessment of Extramammary Paget Disease by Two-Photon Microscopy

Two-photon microscopy techniques are non-linear optical imaging methods which are gaining momentum in the investigation of fixed tissue sections, fresh tissue or even for in vivo experiments. Two-photon excited fluorescence and second harmonic generation are two non-linear optical contrast mechanisms which can be simultaneously used for offering complementary information on the tissue architecture. While the former can originate from endogenous autofluorescence sources (e.g., NADH, FAD, elastin, keratin, lipofuscins, or melanin), or exogenous eosin, the latter is generated in fibrillar structures within living organisms (e.g., collagen and myosin). Here we test the ability of both these contrast mechanisms to highlight features of the extramammary Paget disease on fixed tissue sections prepared for standard histological examination using immunohistochemical markers and hematoxylin and eosin staining. We also demonstrate the label-free abilities of both imaging techniques to highlight histological features on unstained fixed tissue sections. The study demonstrated that two-photon microscopy can detect specific cellular features of the extramammary Paget disease in good correlation with histopathological results.

Intensity-Mosaic: automatic panorama mosaicking of disordered images with insufficient features

Purpose: Handling low-quality and few-feature medical images is a challenging task in automatic panorama mosaicking. Current mosaicking methods for disordered input images are based on feature point matching, whereas in this case intensity-based registration achieves better performance than feature-point registration methods. We propose a mosaicking method that enables the use of mutual information (MI) registration for mosaicking randomly ordered input images with insufficient features. Approach: Dimensionality reduction is used to map disordered input images into a low dimensional space. Based on the low dimensional representation, the image global correspondence can be recognized efficiently. For adjacent image pairs, we optimize the MI metric for registration. The panorama is then created after image blending. We demonstrate our method on relatively lower-cost handheld devices that acquire images from the retina in vivo, kidney ex vivo, and bladder phantom, all of which contain sparse features. Results: Our method is compared with three baselines: AutoStitch, "dimension reduction + SIFT," and "MI-Only." Our method compared to the first two feature-point based methods exhibits 1.25 (ex vivo microscope dataset) to two times (in vivo retina dataset) rate of mosaic completion, and MI-Only has the lowest complete rate among three datasets. When comparing the subsequent complete mosaics, our target registration errors can be 2.2 and 3.8 times reduced when using the microscopy and bladder phantom datasets. Conclusions: Using dimensional reduction increases the success rate of detecting adjacent images, which makes MI-based registration feasible and narrows the search range of MI optimization. To the best of our knowledge, this is the first mosaicking method that allows automatic stitching of disordered images with intensity-based alignment, which provides more robust and accurate results when there are insufficient features for classic mosaicking methods.

Evaluation of in vivo reflectance confocal microscopy in the diagnosis of extramammary Paget's disease

Extramammary Paget's disease (EMPD) is a rare cutaneous malignancy that most commonly affects the apocrine glands of older men and women. Because it is associated with other cancers, early diagnosis and evaluation are needed. This study is to evaluate the value of reflectance confocal microscopy (RCM) in diagnosing EMPD. A total of 73 patients with clinically suspicious diagnosis of EMPD were enrolled in this study, and the RCM device imaged their lesions. Moreover, 67 patients underwent skin biopsies to confirm the diagnosis. We retrospectively analyzed the results of RCM and histological diagnosis and then evaluated the RCM value of biopsy-confirmed lesions. Based on the RCM image analysis, 54 of 73 (74.0%) patients were diagnosed with EMPD. Of all 67 biopsied lesions, 52 (77.6%) were EMPD. Then, we analyzed the RCM characteristics of 52 cases of biopsy-confirmed EMPD, compared their RCM image characteristics of three different lesions of EMPD, and further concluded the key points of EMPD under RCM microscopy based on the 52 EMPD cases. Finally, we focused on the differential diagnosis of EMPD from other skin diseases. RCM showed great diagnostic value in diagnosing EMPD.

Diagnosis of subclinical extramammary Paget's disease with a combination of noninvasive photodynamic diagnosis and reflectance confocal microscopy

Extramammary Paget's disease is a rare skin malignancy, and its diagnosis requires invasive biopsy and histopathological examination. Surgery is the standard treatment for extramammary Paget's disease patients; however, as incision boundaries and the depth of tumor cell infiltration are often unclear, the postoperative recurrence rate is high. We present a case in which we used photodynamic diagnosis in combination with reflectance confocal microscopy before surgery to detect an extramammary Paget's disease lesion that was located 3 cm away from the classical lesion. This secondary lesion exhibited a subclinical presentation, and it was eventually confirmed as an extramammary Paget's disease lesion by pathological examination. During detection using our technique, we delineated the boundaries of the extramammary Paget's disease lesion as a guide for surgical excision. The findings of our case demonstrate that photodynamic diagnosis combined with reflectance confocal microscopy can be used for the noninvasive diagnosis of subclinical extramammary Paget's disease and may be used to guide strategies for planning treatment and preventing relapse.

Treatment of Extramammary Paget Disease and the Role of Reflectance Confocal Microscopy: A Prospective Study

BACKGROUND

Extramammary Paget disease (EMPD) poses treatment challenges. Invasive and noninvasive treatment modalities exist with variable success reported. Reflectance confocal microscopy (RCM) is emerging as an adjuvant diagnostic tool.

OBJECTIVE

To evaluate the treatment of EMPD patients and the role of RCM.

METHODS

Prospective study. Demographic and tumor characteristics were recorded. Handheld-RCM was performed and correlated with histology. Treatment, clearance, pathology, and follow-up were all recorded.

RESULTS

Thirty-six EMPD lesions in 33 patients were included. Mean age was 71.7 years, and 23 were men. Mean number of surgical stages needed to clear margins was 1.9 (SD, 0.9; 1.0-3.0 stages), and mean margin needed to clear was 1.8 cm. Reflectance confocal microscopy correlated well with scouting punch biopsies (kappa, 0.93; p < .001). Disruption of the dermoepidermal junction was associated with invasive EMPD versus in situ (83.3% vs 25.9%) on histology (p = .01).

LIMITATIONS

Relatively small sample size.

CONCLUSION

Extramammary Paget disease is challenging, and lesion demarcation is of the utmost importance. Using a staged surgical excision approach, the mean margins needed were 1.8 cm, less than previously reported. Nonsurgical modalities, including radiation therapy, imiquimod, or photodynamic therapy can be considered if surgery is not pursued. Reflectance confocal microscopy is a valuable noninvasive imaging modality for the management of EMPD.

Utility of photodynamic diagnosis plus reflectance confocal microscopy in detecting the margins of extramammary Paget disease

BACKGROUND

Due to the clinically poorly delineated unclear margin of extramammary Paget disease, the recurrence rate after surgical resection is high.

AIMS

To compare photodynamic diagnosis and photodynamic plus reflectance confocal microscopy diagnosis in determining the tumor margins in patients with extramammary Paget disease.

METHODS

Thirty-six patients with histopathologically confirmed primary extramammary Paget disease between January 2017 to June 2018 were included in the study. The skin lesion margins were preoperatively observed by the naked eye and with photodynamic diagnosis and photodynamic diagnosis plus reflectance confocal microscopy and they were compared to the postoperative histopathological examination results.

RESULTS

Among the 130 sections taken from 36 patients, 83 sections (63.8%, 83/130) had tumor margins beyond the macroscopic line with a distance of 3.5 ± 3.1mm and a median of 2.7mm. Forty-six sections (35.4%, 46/130) exceeded the photodynamic diagnosis marker line with a distance of 2.1 ± 1.7mm and a median of 1.5mm. Twenty seven sections (20.8%, 27/130) were obtained beyond the photodynamic diagnosis plus reflectance confocal microscopy marker line with a distance of 1.4 ± 1.2mm and a median of 0.9mm.

LIMITATIONS

Photodynamic diagnosis and reflectance confocal microscopy detection can be used to observe only the superficial margin of the tumor and not the deep part. Moreover, reflectance confocal microscopy was not used alone as a control.

CONCLUSION

In terms of determining the extramammary Paget disease margin invasively, photodynamic diagnosis and photodynamic diagnosis plus reflectance confocal microscopy were found superior to observations made with the naked eye, while photodynamic diagnosis plus reflectance confocal microscopy was superior to photodynamic diagnosis alone.

Real-time video mosaicking to guide handheld in vivo microscopy

Handheld and endoscopic optical-sectioning microscopes are being developed for noninvasive screening and intraoperative consultation. Imaging a large extent of tissue is often desired, but miniature in vivo microscopes tend to suffer from limited fields of view. To extend the imaging field during clinical use, we have developed a real-time video mosaicking method, which allows users to efficiently survey larger areas of tissue. Here, we modified a previous post-processing mosaicking method so that real-time mosaicking is possible at >30 frames/second when using a device that outputs images that are 400 × 400 pixels in size. Unlike other real-time mosaicking methods, our strategy can accommodate image rotations and deformations that often occur during clinical use of a handheld microscope. We perform a feasibility study to demonstrate that the use of real-time mosaicking is necessary to enable efficient sampling of a desired imaging field when using a handheld dual-axis confocal microscope.

Feasibility of a Video-Mosaicking Approach to Extend the Field-of-View For Reflectance Confocal Microscopy in the Oral Cavity In Vivo

BACKGROUND

Reflectance confocal microscopy (RCM) is a developing approach for noninvasive detection of oral lesions with label-free contrast and cellular-level resolution. For access into the oral cavity, confocal microscopes are being configured with small-diameter telescopic probes and small objective lenses. However, a small probe and objective lens allows for a rather small field-of-view relative to the large areas of tissue that must be examined for diagnosis. To extend the field-of-view for intraoral RCM imaging, we are investigating a video-mosaicking approach.

METHODS

A relay telescope and objective lens were adapted to an existing confocal microscope for access into the oral cavity. Imaging was performed using metal three-dimensional-printed objective lens front-end caps with coverslip windows to contact and stabilize the tissue and set depth. Four healthy volunteers (normal oral mucosa), one patient (with an amalgam tattoo) in a clinical setting, and 20 anesthetized patients (with oral squamous cell carcinoma [OSCC]) in a surgical setting were imaged. Instead of the usual still RCM images, videos were recorded and then processed into video-mosaics. Thirty video-mosaics were read and qualitatively assessed by an expert reader of RCM images of the oral mucosa.

RESULTS

Whereas the objective lens' native field-of-view is 0.75 mm × 0.75 mm, the video-mosaics display larger areas, ranging from 2 mm × 2 mm to 4 mm × 2 mm, with resolution, morphologic detail, and image quality that is preserved relative to that observed in the original videos (individual images). Video-mosaics in healthy volunteers' and the patients' images showed cellular morphologic patterns in the lower epithelium and at the epithelial junction, and connective tissue along with capillary loops and blood flow in the deeper lamina propria. In OSCC, tumor nests could be observed along with normal looking mucosa in margin areas.

CONCLUSIONS

Video-mosaicking is a reasonably quick and efficient approach for extending the field-of-view of RCM imaging, which can, to some extent, overcome the inherent limitation of an intraoral probe's small field-of-view. Reading video-mosaics can mimic the procedure for examining pathology: initial visualization of the spatial cellular and morphologic patterns of the tumor and the spread of tumor margins over larger areas of the lesion, followed by digitally zooming (magnifying) for closer inspection of suspicious areas. However, faster processing of videos into video-mosaics will be necessary, to allow examination of video-mosaics in real-time at the bedside. Lasers Surg. Med. 51:439-451, 2019. © 2019 Wiley Periodicals, Inc.

A review of non-invasive imaging in extramammary Paget's disease

Extramammary Paget's Disease (EMPD) is a rare intraepithelial adenocarcinoma that classically manifests with pruritic, erythematous and scaling plaques. The clinical picture frequently mimics inflammatory or infectious conditions and is thus commonly misdiagnosed. The assessment of tumour margins is equally challenging as tumours have a propensity to spread beyond clinically visible boundaries. Appropriate non-invasive diagnostic tools can assist in the early detection, diagnosis and management of EMPD. This paper will review the literature on non-invasive imaging modalities used in EMPD. Articles from the PubMed database were selected based on relevance to the topic of this review. Articles that were not specific to EMPD and non-invasive imaging were excluded. Search strategy is further described in the methods section below. Eighteen articles were selected for this review: six PET/CT, five reflectance confocal microscopy (RCM), two photodynamic diagnosis (PDD), two dermoscopy, two MRI and one optical coherence tomography (OCT) paper(s). Dermoscopy, PDD, RCM and OCT can help to distinguish malignant conditions, including EMPD, from benign conditions. RCM and OCT can identify atypical cells in real-time, and have the potential to improve the accuracy of surgical margins intraoperatively and overall management. Distinctive confocal characteristics of EMPD have been described using RCM. The sensitivity and specificity of these findings require additional validation. Radiographic techniques also play a central role in the diagnosis of EMPD and assessment of disease spread. PET/CT and MRI can detect primary disease, nodal and distant metastases, with superior delineation of disease spread on MRI. Limitations of PET/CT are mainly related to primary tumour thickness, and size and FDG-avidity of nodal and distant metastases. Limitations of MRI include the fact that few studies have examined its use in EMPD; additional research is warranted. Randomized controlled trials and large prospective studies evaluating the use of non-invasive imaging in EMPD are needed.

The diagnosis and management of extramammary Paget's disease

INTRODUCTION

Extramammary Paget's disease (EMPD) is a rare neoplastic condition that commonly affects the anogenital area in the elderly. Owing to its low incidence, limited data regarding EMPD's diagnosis and treatment have been available. This review article aims to explore the current knowledge of EMPD to improve the management of this disease. Areas covered: This review outlines the diagnosis and management of EMPD. Articles on this issue that had been published in PubMed were identified and surveyed. We provide an overview of the reported studies, focusing on the recent advances in this field. Expert commentary: A new TNM staging system specific for EMPD has been proposed in Japan; the T category was classified by tumor thickness and lymphovascular invasion, the N category by the number of metastatic lymph nodes, and the M category by systemic metastases. As new diagnostic tools for EMPD, dermoscopy and reflectance confocal microscopy have emerged. Recent reports about Mohs micrographic surgery, mapping biopsy, radiation therapy, photodynamic therapy, topical imiquimod, conventional chemotherapy, and targeted therapy are also discussed. Despite the increasing publications of EMPD, limited information on this condition is available and the accumulation of more data is required.

Correlation of Handheld Reflectance Confocal Microscopy With Radial Video Mosaicing for Margin Mapping of Lentigo Maligna and Lentigo Maligna Melanoma

Importance

The management of lentigo maligna (LM) and LM melanoma (LMM) is challenging because of extensive subclinical spread and its occurrence on cosmetically sensitive areas. Reflectance confocal microscopy (RCM) improves diagnostic accuracy for LM and LMM and can be used to delineate their margins.

Objectives

To evaluate whether handheld RCM with radial video mosaicing (HRCM-RV) offers accurate presurgical assessment of LM and LMM margins.

Design, Setting, and Participants

This prospective study included consecutive patients with biopsy-proven LM and LMM located on the head and neck area who sought consultation for surgical management from March 1, 2016, through March 31, 2017, at the Dermatology Service of the Memorial Sloan Kettering Cancer Center. Thirty-two patients underwent imaging using HRCM-RV, and 22 patients with 23 LM or LMM lesions underwent staged surgery and contributed to the analysis.

Main Outcomes and Measures

Clinical lesion size and area, LM and LMM area based on HRCM-RV findings, surgical defect area estimated by HRCM-RV, and observed surgical defect area. In addition, the margins measured in millimeters estimated for tumor clearance in each quadrant based on HRCM-RV findings were calculated and compared with the surgical margins.

Results

Among the 22 patients (12 men and 10 women; mean [SD] age, 69.0 [8.6] years [range, 46-83 years]) with 23 lesions included in the final analysis, the mean (SD) surgical defect area estimated with HRCM-RV was 6.34 (4.02) cm2 and the mean (SD) area of surgical excision with clear margins was 7.74 (5.28) cm2. Overall, controlling for patient age and previous surgery, surgical margins were a mean of 0.76 mm (95% CI, 0.67-0.84 mm; P < .001) larger than the HRCM-RV estimate.

Conclusions and Relevance

Mapping of LM and LMM with HRCM-RV estimated defects that were similar to but slightly smaller than those found in staged excision. Thus, mapping of LM using HRCM-RV can help spare healthy tissue by reducing the number of biopsies needed in clinically uncertain areas and may be used to plan treatment of LM and LMM and counsel patients appropriately.

Automated video-mosaicking approach for confocal microscopic imaging in vivo: an approach to address challenges in imaging living tissue and extend field of view

We describe a computer vision-based mosaicking method for in vivo videos of reflectance confocal microscopy (RCM). RCM is a microscopic imaging technique, which enables the users to rapidly examine tissue in vivo. Providing resolution at cellular-level morphology, RCM imaging combined with mosaicking has shown to be highly sensitive and specific for non-invasively guiding skin cancer diagnosis. However, current RCM mosaicking techniques with existing microscopes have been limited to two-dimensional sequences of individual still images, acquired in a highly controlled manner, and along a specific predefined raster path, covering a limited area. The recent advent of smaller handheld microscopes is enabling acquisition of videos, acquired in a relatively uncontrolled manner and along an ad-hoc arbitrarily free-form, non-rastered path. Mosaicking of video-images (video-mosaicking) is necessary to display large areas of tissue. Our video-mosaicking methods addresses this need. The method can handle unique challenges encountered during video capture such as motion blur artifacts due to rapid motion of the microscope over the imaged area, warping in frames due to changes in contact angle and varying resolution with depth. We present test examples of video-mosaics of melanoma and non-melanoma skin cancers, to demonstrate potential clinical utility.