New concepts in vocal fold imaging: a review

From Hype To Reality: A Narrative Review on the Promising Role of Artificial Intelligence in Larynx Cancer Detection and Transoral Microsurgery

Early larynx cancer detection plays a crucial role in improving treatment outcomes and recent studies have shown promising results in using artificial intelligence for larynx cancer detection. Artificial intelligence also has the potential to enhance transoral larynx microsurgery. This narrative review summarizes the current evidence regarding its use in larynx cancer detection and potential applications in transoral larynx microsurgery. The utilization of artificial intelligence in larynx cancer detection with white light endoscopy and narrow-band imaging helps improve diagnostic accuracy and efficiency. It can also potentially enhance transoral larynx microsurgery by aiding surgeons in real-time decision-making and minimizing the risk of complications. However, further prospective studies are warranted to validate the findings, and additional research is necessary to optimize the integration of artificial intelligence in our clinical practice.

Quasi-static ultrasound elastography of ex-vivo porcine vocal folds during passive elongation and adduction

OBJECTIVES

The elastic properties of the vocal folds have great influence on the primary sound and thus on the entire subsequent phonation process. Muscle contractions in the larynx can alter the elastic properties of the vocal fold tissue. Quasi-static ultrasound elastography is a non-destructive examination method that can be applied to ex-vivo vocal folds. In this work, porcine vocal folds were passively elongated and adducted and the changes of the elastic properties due to that manipulations were measured.

METHODS

Manipulations were performed by applying force to sewn-in sutures. Elongation was achieved by a suture attached to the thyroid cartilage, which was pulled forward by defined weights. Adduction was effected by two sutures exerting torque on the arytenoid cartilage. A series of ten specimens was examined and evaluated using a quasi-static elastography algorithm. In addition, the surface stretch was measured optically using tattooed reference points.

RESULTS

This study showed that the expected stiffening of the tissue during the manipulations can be measured using quasi-static ultrasound elastography. The measured effect of elongation and adduction, both of which result in stretching of the tissue, is stiffening. However, the relative change of specific manipulations is not the same for the same load on different larynges, but is rather related to stretch caused and other uninvestigated factors.

CONCLUSION

The passive elongation and adduction of vocal folds stiffen the tissue of the vocal folds and can be measured using ultrasound elastography.

Comparison of narrow band and fluorescence molecular imaging to improve intraoperative tumour margin assessment in oral cancer surgery

OBJECTIVE

New techniques have emerged to aid in preventing inadequate margins in oral squamous cell carcinoma (OSCC) surgery, but studies comparing different techniques are lacking. Here, we compared narrow band imaging (NBI) with fluorescence molecular imaging (FMI), to study which intraoperative technique best assesses the mucosal tumour margins.

MATERIALS AND METHODS

NBI was performed in vivo and borders were marked with three sutures. For FMI, patients received 75 mg of unlabelled cetuximab followed by 15 mg cetuximab-800CW intravenously-two days prior to surgery. The FMI borders were defined on the excised specimen. The NBI borders were correlated with the FMI outline and histopathology.

RESULTS

Sixteen patients were included, resulting in 31 NBI and 30 FMI measurements. The mucosal border was delineated within 1 mm of the tumour border in 4/31 (13 %) of NBI and in 16/30 (53 %) FMI cases (p = 0.0008), and within 5 mm in 23/31 (74 %) of NBI and in 29/30 (97 %) of FMI cases (p = 0.0048). The median distance between the tumour border and the imaging border was significantly greater for NBI (3.2 mm, range -6.1 to 12.8 mm) than for FMI (0.9 mm, range -3.0 to 7.4 mm; p = 0.028). Submucosal extension and previous irradiation reduced NBI accuracy.

CONCLUSION

Ex vivo FMI performed more accurately than in vivo NBI in mucosal margin assessment, mainly because NBI cannot detect submucosal extension. NBI adequately identified the mucosal margin especially in early-stage and not previously irradiated tumours, and may therefore be preferable in these tumours for practical and cost-related reasons.

Otorhinolaryngological Advancements in Phoniatrics

The production of voice is a powerful tool not only for communication, but also for artistic performances [...]

Validation of the European Laryngological Society classification of glottic vascular changes as seen by narrow band imaging in the optical biopsy setting

Purpose

In 2016, the European Laryngological Society (ELS) proposed a classification for vascular changes occurring in glottic lesions as visible by narrow band imaging (NBI), based on the dichotomic distinction between longitudinal vessels (not suspicious) and perpendicular ones (suspicious). The aim of our study was to validate this classification assessing the interobserver agreement and diagnostic test performance in detecting the final histopathology.

Methods

A retrospective study was carried out by reviewing clinical charts, preoperative videos, and final pathologic diagnosis of patients submitted to transoral microsurgery for laryngeal lesions in two Italian referral centers. In each institution, two physicians, independently re-assessed each case applying the ELS classification.

Results

The cohort was composed of 707 patients. The pathologic report showed benign lesions in 208 (29.5%) cases, papillomatosis in 34 (4.8%), squamous intraepithelial neoplasia (SIN) up to carcinoma in situ in 200 (28.2%), and squamous cell carcinoma (SCC) in 265 (37.5%). The interobserver agreement was extremely high in both institutions (k = 0.954, p < 0.001 and k = 0.880, p < 0.001). Considering the diagnostic performance for identification of at least SIN or SCC, the sensitivity was 0.804 and 0.902, the specificity 0.793 and 0.581, the positive predictive value 0.882 and 0.564, and the negative predictive value 0.678 and 0.908, respectively.

Conclusion

The ELS classification for NBI vascular changes of glottic lesions is a highly reliable tool whose systematic use allows a better diagnostic evaluation of suspicious laryngeal lesions, reliably distinguishing benign ones from those with a diagnosis of papillomatosis, SIN or SCC, thus paving the way towards confirmation of the optical biopsy concept.

Laryngeal Image Processing of Vocal Folds Motion

This review provides a comprehensive compilation, from a digital image processing point of view of the most important techniques currently developed to characterize and quantify the vibration behaviour of the vocal folds, along with a detailed description of the laryngeal image modalities currently used in the clinic. The review presents an overview of the most significant glottal-gap segmentation and facilitative playbacks techniques used in the literature for the mentioned purpose, and shows the drawbacks and challenges that still remain unsolved to develop robust vocal folds vibration function analysis tools based on digital image processing.

Learning curve for endoscopic evaluation of vocal folds lesions with narrow band imaging

Introduction

The endoscopic methods are progressing and becoming more common in routine clinical diagnosis in the field of otorhinolaryngology. Relatively large amount of researches have proved high accuracy of narrow band imaging endoscopy in differentiating benign and malignant lesions within vocal folds. However, little is known about learning curve in narrow band imaging evaluation of laryngeal lesions.

Objective

The aim of this study was to determine the learning curve for the narrow band imaging evaluation of vocal folds pathologies depending on the duration of the procedure.

Methods

Records of 134 narrow band imaging that were analyzed in terms of the duration of the procedure and the accuracy of diagnosis confirmed by histopathological diagnosis were enrolled in the study. The narrow band imaging examinations were performed sequentially by one investigator over a period of 18 months.

Results

The average duration of narrow band imaging recordings was 127.82 s. All 134 studies were divided into subsequent series of several elements. An evident decrease in time of investigation was noticed between 13th and 14th series, when the examinations were divided into 5 elements series, which corresponds to the difference between 65th and 70th subsequent narrow band imaging examination. Parallel groups of 67 examinations were created. Group 1 included 1st to 67th subsequent narrow band imaging examination; Group 2 – 68th to 134th narrow band imaging examinations. The non-parametric U Mann–Whitney test confirmed statistically significant difference between the mean duration of narrow band imaging examination in both groups 160.5 s and 95.1 s, respectively (p < 10⁻⁷). Sensitivity and specificity of narrow band imaging examination in the first group were respectively: 83.7% and 76.7%. In the second group, these indicators amounted 98.1% and 80% respectively.

Conclusions

A minimum of 65th–70th narrow band imaging examinations are required to reach a plateau phase of the learning process in assessment of glottis lesions. Analysis of learning curves is useful for the development of training programs and determination of a mastery level.

Imaging the Vocal Folds: A Feasibility Study on Strain Imaging and Elastography of Porcine Vocal Folds

Vocal folds are an essential part of human voice production. The biomechanical properties are a good indicator for pathological changes. In particular, as an oscillation system, changes in the biomechanical properties have an impact on the vibration behavior. Subsequently, those changes could lead to voice-related disturbances. However, no existing examination combines biomechanical properties and spatial imaging. Therefore, we propose an image registration-based approach, using ultrasound in order to gain this information synchronously. We used a quasi-static load to compress the tissue and measured the displacement by image registration. The strain distribution was directly calculated from the displacement field, whereas the elastic properties were estimated by a finite element model. In order to show the feasibility and reliability of the algorithm, we tested it on gelatin phantoms. Further, by examining ex vivo porcine vocal folds, we were able to show the practicability of the approach. We displayed the strain distribution in the tissue and the elastic properties of the vocal folds. The results were superimposed on the corresponding ultrasound images. The findings are promising and show the feasibility of the suggested approach. Possible applications are in improved diagnosis of voice disorders, by measuring the biomechanical properties of the vocal folds with ultrasound. The transducer will be placed on the vocal folds of the anesthetized patient, and the elastic properties will be measured. Further, the understanding of the vocal folds’ biomechanics and the voice forming process could benefit from it.

Development of three-dimensional laryngostroboscopy for office-based laryngeal diagnostics and phonosurgical therapy

OBJECTIVE

To develop a three-dimensional (3D) laryngostroboscopic examination unit, compare the optic playback quality in relation to established 2D procedures, and report the first case series using 3D rigid laryngostroboscopy for diagnosis and management of laryngotracheal diseases.

STUDY DESIGN

Laboratory study, prospective case series.

METHODS

The optical efficacy of newly developed rigid 3D endoscopes was examined in a laboratory setting. Diagnostic suitability was investigated in 100 subjects (50 male, 50 female) receiving 2D high-definition (HD) and 3D laryngostroboscopy. Two of the subjects subsequently underwent 3D-assisted office-based transoral phonosurgery under local anesthesia. Main outcome measures were comparative visualization of laryngotracheal pathologies, influence on preoperative planning, and evaluation of prognostic factors for the outcome of phonosurgical interventions.

RESULTS

Three-dimensional endostroboscopic procedures were effectively optimized to establish an examination protocol for all-day clinical use. Office-based 3D laryngostroboscopy was successfully applied in subjects with normal anatomy (n = 10) and various laryngotracheal findings (n = 90). In comparison to 2D HD videolaryngostroboscopy, the 3D view offered enhanced visualization of laryngotracheal anatomy, with qualitatively improved depth perception and spatial representation. In organic pathologies, this resulted in a more precise indication of phonosurgical procedures, increased accuracy in surgical planning, facilitated office-based endoscopic surgery, and better evaluation of prognostic factors for the outcome of phonosurgical interventions.

CONCLUSION

Three-dimensional laryngostroboscopy proved to increase the understanding of functional and surgical anatomy. Its application has enormous potential for improving the diagnostic value of laryngoscopy, surgical precision in laryngotracheal interventions, tissue preservation, and methods of teaching.

LEVEL OF EVIDENCE

NA Laryngoscope, 128:2823-2831, 2018.

Narrow band imaging versus laryngovideostroboscopy in precancerous and malignant vocal fold lesions

BACKGROUND

This is a comparative analysis of the diagnostic accuracy of narrow band imaging (NBI) and laryngovideostroboscopy (LVS) in the assessment of premalignant and malignant vocal fold lesions.

METHODS

A prospective analysis was performed on 105 consecutive patients with vocal fold lesions. The NBI and LVS were obtained before the microsurgery.

RESULTS

The NBI and LVS showed no significant differences in identifying premalignant and malignant pathologies. However, in analysis restricted to identification of only malignant lesions, the specificity (88.9% vs 20.6%), accuracy (90.5% vs 51.4%), and positive predictive value (PPV; 84.8% vs 45.1%) were significantly higher for NBI (P value < .001; .015; and .045, respectively). A comparison of LVS scored results relative to each NBI type revealed statistically significant differences (P < .001). A moderate positive correlation between NBI and LVS was demonstrated (P = .54).

CONCLUSION

The NBI and LVS are useful, complementary tools in evaluating early potential vocal fold malignancies. The NBI was superior to LVS on several statistical analyses.

Guidelines for the Surgical Management of Laryngeal Cancer: Korean Society of Thyroid-Head and Neck Surgery

Korean Society of Thyroid-Head and Neck Surgery appointed a Task Force to develop clinical practice guidelines for the surgical treatment of laryngeal cancer. This Task Force conducted a systematic search of the EMBASE, MEDLINE, Cochrane Library, and KoreaMed databases to identify relevant articles, using search terms selected according to the key questions. Evidence-based recommendations were then created on the basis of these articles. An external expert review and Delphi questionnaire were applied to reach consensus regarding the recommendations. The resulting guidelines focus on the surgical treatment of laryngeal cancer with the assumption that surgery is the selected treatment modality after a multidisciplinary discussion in any context. These guidelines do not, therefore, address non-surgical treatment such as radiation therapy or chemotherapy. The committee developed 62 evidence-based recommendations in 32 categories intended to assist clinicians during management of patients with laryngeal cancer and patients with laryngeal cancer, and counselors and health policy-makers.

Narrow Band Imaging

Objectives:

Narrow band imaging (NBI) is supposed to be a technique for a better visualization of vessel structures in superficial tissue as it selects the wavelengths of hemoglobin. It was hypothesized that, in the regular follow-up examination of patients with recurrent laryngeal papillomatosis, NBI enables a better detection of laryngeal papillomatosis in contrast to normal white light endoscopy.

Methods:

Eleven patients, 10 with a known recurrent papillomatosis (8 with a relapse, 2 without) and 1 with a primary diagnosis of papillomatosis, were examined with normal white light and NBI endoscopy. Twenty-six video sequences (11 white, 11 NBI, 4 doubled for validity) were generated and randomly presented to 20 otolaryngologists who rated the videos in terms of lesions seen and number of lesions identified. Results were compared with the histopathologic findings of microlaryngoscopy.

Results:

Detection of papillomatosis and the correct number of lesions identified were more accurate with NBI than with normal white light endoscopy. There was a significantly higher probability of detecting laryngeal papillomata with NBI.

Conclusions:

NBI endoscopy enables a more accurate detection of laryngeal papillomatosis than white light endoscopy.