Differences in the diagnostic value between fiberoptic and high definition laryngoscopy for the characterisation of pharyngeal and laryngeal lesions: A multi-observer paired analysis of videos

Diagnosis of laryngopharyngeal carcinoma through office-based flexible laryngoscopy as a reliable alternative for biopsies under general anesthesia: Faster diagnostics with equal oncological outcome

PURPOSE

Diagnostic endoscopy with biopsy under general anesthesia (DE-GA) is still considered as the established standard to assess laryngopharyngeal cancer patients. Office-based flexible laryngoscopic biopsy (FLB) offers an alternative, but the effect on oncological outcome remains uncertain. Therefore, the diagnostic process and survival of patients undergoing FLB, compared to those undergoing DE-GA were evaluated.

METHODS

Patients suspected of laryngopharyngeal cancer who underwent FLB were evaluated. Patients with FLB-confirmed squamous cell carcinoma (SCC) were matched with DE-GA patients based on tumor site, T-classification, N-classification, age, and p16 overexpression. Time from first visit to diagnosis (FVD), time to treatment interval (TTI), disease-specific survival (DSS) and overall survival (OS) were analyzed.

RESULTS

FLB yielded a definitive diagnosis in 155/164 (95 %) patients. No complications were observed. Ninety-eight of the 124 patients in which FLB revealed a SCC received curative treatment and were compared with 98 matched patients who underwent DE-GA. Median FVD interval was 6 days after FLB and 15 days after DE-GA (p < 0.001). Median TTI interval (FLB: 28 days, DE-GA: 28 days) was equal (p = 0.91). Oncological outcomes were comparable (p > 0.05) between FLB (OS: 2-yr: 76 %, 5-yr: 42 %; DSS: 2-yr: 86 %, 5-yr: 85 %) and DE-GA groups (OS: 2-yr: 76 %, 5-yr: 50 %; DSS: 2-yr: 81 %, 5-yr: 79 %).

CONCLUSION

FLB in the outpatient setting demonstrates a high diagnostic accuracy, is safe, accelerates the diagnostic process and has no negative effects on clinical outcome compared to DE-GA. Therefore, FLB should be considered as the standard diagnostic procedure in patients suspected of laryngopharyngeal cancer.

The influence of clinical experience on reliable evaluation of pharyngeal and laryngeal lesions: comparison of high-definition laryngoscopy using narrow band imaging with fibre-optic laryngoscopy

BACKGROUND

Fibre-optic laryngoscopy is still widely used in daily clinical practice; however, high-definition laryngoscopy using narrow band imaging could be more reliable in characterising pharyngeal and laryngeal lesions.

METHODS

Endoscopic videos were assessed in a tertiary referral hospital by 12 observers with different levels of clinical experience. Thirty pairs of high-definition laryngoscopy with narrow band imaging and fibre-optic laryngoscopy videos were judged twice, with an interval of two to four weeks, in a random order. Inter- and intra-observer reliability, sensitivity and specificity were calculated in terms of detecting a malignant lesion and a specific histological entity, for beginners, trained observers and experts.

RESULTS

Using high-definition laryngoscopy with narrow band imaging, inter-observer reliability for detecting malignant lesions increased from moderate to substantial in trained observers and experts (high-definition laryngoscopy with narrow band imaging κ = 0.66 and κ = 0.77 vs fibre-optic laryngoscopy κ = 0.51 and κ = 0.56, for trained observers and experts respectively) and sensitivity increased by 16 per cent.

CONCLUSION

Inter-observer reliability increased with the level of clinical experience, especially when using high-definition laryngoscopy with narrow band imaging.

Edge Enhancement Optimization in Flexible Endoscopic Images to the Perception of Ear, Nose and Throat Professionals

OBJECTIVES

Digital endoscopes are connected to a video processor that applies various operations to process the image. One of those operations is edge enhancement that sharpens the image. The purpose of this study was to (1) quantify the level of edge enhancement, (2) measure the effect on sharpness and image noise, and (3) study the influence of edge enhancement on image quality perceived by ENT professionals.

METHODS

Three digital flexible endoscopic systems were included. The level of edge enhancement and the influence on sharpness and noise were measured in vitro, while systematically varying the levels of edge enhancement. In vivo images were captured at identical levels of one healthy larynx. Each series of in vivo images was presented to 39 ENT professionals according to a forced pairwise comparison test, to select the image with the best image quality for diagnostic purposes. The numbers of votes were converted to a psychometric scale of just noticeable differences (JND) according to the Thurstone V model.

RESULTS

The maximum level of edge enhancement varied per endoscopic system and ranged from 0.8 to 1.2. Edge enhancement increased sharpness and noise. Images with edge enhancement were unanimously preferred to images without edge enhancement. The quality difference with respect to zero edge enhancement reaches an optimum at levels between 0.7 and 0.9.

CONCLUSION

Edge enhancement has a major impact on sharpness, noise, and the resulting perceived image quality. We conclude that ENT professionals benefit from this video processing and should verify if their equipment is optimally configured.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:842-847, 2024.

Influence of edge enhancement applied in endoscopic systems on sharpness and noise

Significance

Flexible endoscopes are essential for medical internal examinations. Digital endoscopes are connected to a video processor that can apply various operations to enhance the image. One of those operations is edge enhancement, which has a major impact on the perceived image quality by medical professionals. However, the specific methods and parameters of this operation are undisclosed and the arbitrary units to express the level of edge enhancement differ per video processor.

Aim

Objectively quantify the level of edge enhancement from the recorded images alone, and measure the effect on sharpness and noise

Approach

Edge enhancement was studied in four types of flexible digital ear nose and throat endoscopes. Measurements were performed using slanted edges and gray patches. The level of edge enhancement was determined by subtracting the step response of an image without edge enhancement from images with selected settings of edge enhancement and measuring the resulting peak-to-peak differences. These values were then normalized by the step size. Sharpness was characterized by observing the normalized modulation transfer function (MTF) and computing the spatial frequency at 50% MTF. The noise was measured on the gray patches and computed as a weighted sum of variances from the luminance and two chrominance channels of the pixel values.

Results

The measured levels were consistent with the level set via the user interface on the video processor and varied typically from 0 to 1.3. Both sharpness and noise increase with larger levels of edge enhancement with factors of 3 and 4 respectively.

Conclusions

The presented method overcomes the issue of vendors expressing the level of edge enhancement each differently in arbitrary units. This allows us to compare the effects, and we can start exploring the relationship with the subjectively perceived image quality by medical professionals to find substantiated optimal settings.

Implementation of functional imaging using 11C-methionine PET-CT co-registered with MRI for advanced surgical planning and decision making in prolactinoma surgery

PURPOSE

To report the first experience of our multidisciplinary team with functional imaging using ¹¹C-methionine positron emission tomography-computed tomography (¹¹C-methionine PET-CT) co-registered with MRI (Met-PET/MRI^CR) in clinical decision making and surgical planning of patients with difficult to treat prolactinoma.

METHODS

In eighteen patients with prolactinoma, referred to our tertiary referral centre because of intolerance or resistance for dopamine agonists (DA), Met-PET/MRI^CR was used to aid decision-making regarding therapy.

RESULTS

Met-PET/MRI^CR was positive in 94% of the patients. MRI and Met-PET/MRI^CR findings were completely concordant in five patients, partially concordant in nine patients, and non-concordant in four patients. In five patients Met-PET/MRI^CR identified lesion(s) that were retrospectively also visible on MRI. Met-PET/MRI^CR was false negative in one patient, with a cystic adenoma on conventional MRI. Thirteen patients underwent transsphenoidal surgery, with nine achieving full biochemical remission, two clinical improvement and near normalized prolactin levels, and one patient clinical improvement with significant tumour reduction. Hence, nearly all patients (94%) were considered to have a positive outcome. Permanent complication rate was low. Three patients continued DA, two patients have a wait and scan policy.

CONCLUSION

Met-PET/MRI^CR can provide additional information to guide multidisciplinary preoperative and intraoperative decision making in selected cases of prolactinoma. This approach resulted in a high remission rate with a low rate of complications in our expert centre.

Deep Learning Applied to White Light and Narrow Band Imaging Videolaryngoscopy: Toward Real-Time Laryngeal Cancer Detection

OBJECTIVES

To assess a new application of artificial intelligence for real-time detection of laryngeal squamous cell carcinoma (LSCC) in both white light (WL) and narrow-band imaging (NBI) videolaryngoscopies based on the You-Only-Look-Once (YOLO) deep learning convolutional neural network (CNN).

STUDY DESIGN

Experimental study with retrospective data.

METHODS

Recorded videos of LSCC were retrospectively collected from in-office transnasal videoendoscopies and intraoperative rigid endoscopies. LSCC videoframes were extracted for training, validation, and testing of various YOLO models. Different techniques were used to enhance the image analysis: contrast limited adaptive histogram equalization, data augmentation techniques, and test time augmentation (TTA). The best-performing model was used to assess the automatic detection of LSCC in six videolaryngoscopies.

RESULTS

Two hundred and nineteen patients were retrospectively enrolled. A total of 624 LSCC videoframes were extracted. The YOLO models were trained after random distribution of images into a training set (82.6%), validation set (8.2%), and testing set (9.2%). Among the various models, the ensemble algorithm (YOLOv5s with YOLOv5m-TTA) achieved the best LSCC detection results, with performance metrics in par with the results reported by other state-of-the-art detection models: 0.66 Precision (positive predicted value), 0.62 Recall (sensitivity), and 0.63 mean Average Precision at 0.5 intersection over union. Tests on the six videolaryngoscopies demonstrated an average computation time per videoframe of 0.026 seconds. Three demonstration videos are provided.

CONCLUSION

This study identified a suitable CNN model for LSCC detection in WL and NBI videolaryngoscopies. Detection performances are highly promising. The limited complexity and quick computational times for LSCC detection make this model ideal for real-time processing.

LEVEL OF EVIDENCE

3 Laryngoscope, 2021.

High-definition videolaryngoscopy is superior to fiberoptic laryngoscopy: a 111 multi-observer study

Purpose

This study aims to analyse differences in fiberoptic laryngoscopy (FOL) versus high definition laryngoscopy (HDL) by examining videolaryngoscopy images by a large group of observers with different levels of clinical expertise in ear, nose and throat (ENT) medicine.

Methods

This study is a 111 observer paired analysis of laryngoscopy videos during an interactive presentation. During a National Meeting of the Dutch Society of ENT/Head and Neck Surgery, observers assessed both FOL and HDL videos of nine cases with additional clinical information. Observers included 41 ENT consultants (36.9%), 34 ENT residents (30.6%), 22 researchers with Head and Neck interest (19.8%) and 14 with unspecified clinical expertise (12.6%). For both laryngoscopic techniques, sensitivity, specificity, positive and negative predictive value and diagnostic accuracy were determined for identifying a normal glottis, hyperkeratosis, radiotherapy adverse effects and squamous cell carcinoma. The sensitivities for FOL and HDL were analysed with regard to the different levels of clinical expertise.

Results

The overall sensitivity for correctly identifying the specific histological entity was higher in HDL (FOL 61% vs HDL 66.3%, p < 0.05). HDL was superior to FOL in identifying a normal glottis (FOL 68.1% vs HDL 91.6%, p < 0.01) and squamous cell carcinoma (FOL 70.86% vs HDL 79.41%, p = 0.02). Residents and researchers with Head and Neck interest diagnosed laryngeal lesions more correctly with HDL (p < 0.05).

Conclusions

In a large population of observers with different levels of clinical expertise, HDL is superior to FOL in identifying laryngeal lesions.

Differences in the diagnostic value between fiberoptic and high definition laryngoscopy for the characterisation of pharyngeal and laryngeal lesions: A multi-observer paired analysis of videos

OBJECTIVES

High definition laryngoscopy (HDL) could lead to better interpretation of the pharyngeal and laryngeal mucosa than regularly used fiberoptic laryngoscopy (FOL). The primary aim of this study is to quantify the diagnostic advantage of HDL over FOL in detecting mucosal anomalies in general, in differentiating malignant from benign lesions and in predicting specific histological entities. The secondary aim is to analyse image quality of both laryngoscopes.

DESIGN

Retrospective paired analysis with multiple observers evaluating endoscopic videos simulating daily clinical practice.

SETTING

A tertiary referral hospital.

PARTICIPANTS

In 36 patients, both FOL and HDL videos were obtained. Six observers were provided with additional clinical information, and 36 FOL and HDL videos were evaluated in a randomised order.

MAIN OUTCOME MEASURES

Sensitivity, specificity, positive and negative predictive value and diagnostic accuracy of observers using both flexible laryngoscopes were calculated for detection of mucosal lesions in general and uncovering malignant lesions. Sensitivities were calculated for prediction of specific histological entities. Image quality (scale 1-10) was assessed for both flexible laryngoscopes.

RESULTS

HDL reached higher sensitivity compared to FOL for detection of mucosal abnormalities in general (96.0% vs 90.4%; P = .03), differentiating malignant from benign lesions (91.7% vs 79.8%; P = .03) and prediction of specific histological entities (59.7% vs 47.2%; P < .01). Image quality was judged better with HDL in comparison with FOL (mean: 8.4 vs 5.4, P < .01).

CONCLUSIONS

HDL is superior to FOL in detecting mucosal anomalies in general, malignancies and specific histological entities. Image quality is considered as superior using HDL compared to FOL.