[Sonography of the larynx--an alternative to laryngoscopy?]

Value of laryngeal ultrasound in comparison with flexible laryngoscope in diagnosis of various laryngeal masses: a cross-sectional study

Background

The term "vocal cord mass" refers to any abnormal growth of the vocal cords. This may include nodules, cysts, polyps, or cancers. Hoarseness of voice is considered the most common symptom of laryngeal lesions. Ultrasound imaging has evolved into a valuable and effective technique for evaluating the head and neck region, including the larynx's structure. Our aim is to evaluate laryngeal ultrasound as an alternative technique to the flexible laryngoscope in the diagnosis and assessment of various laryngeal masses.

Results

The study included 30 males (57.7%) and 22 females (42.3%) who presented with hoarseness of voice. All patients had laryngeal ultrasonography, which was followed by flexible laryngoscopy. The most commonly affected cord was the left vocal cord (42.3%), followed by the right vocal cord (32.7%), and finally both of them (25%). The sensitivity of laryngeal ultrasonography was 88.5% compared to the gold standard flexible laryngoscopy (p value 0.031).

Conclusions

The laryngeal ultrasonography is a highly successful technique in the diagnosis and assessment of various laryngeal masses and could be complementary to flexible laryngoscopy in many cases, especially when laryngoscopy is contraindicated, with relatively high sensitivity in the detection of laryngeal masses.

Synchronous video laryngoscopy and sonography of the larynx in children

Unlike laryngoscopy, laryngeal sonography is easily applicable, well tolerated by young children and less exhausting for the examiner. The aim of this study was to determine if sonography can adequately visualize the laryngeal structures and vocal fold movements of children. Synchronic video laryngoscopy and sonography of the larynx were performed in 35 children (aged 2-8 years) without a laryngeal disease. 10 investigators at differing stages of otolaryngological training were tasked with identifying vocal fold movement and specific anatomical structures after seeing (1) the sonography-only video and (2) the sonography video with a laryngoscopy video overlay. The percentage of correct identification of the structures and the vocal cord movement with and without additional video-overlay was compared. A sonographical view of the larynx could be found and the following anatomical structures were identified: subcutaneous fat tissue, left and right sternohyoid and thyrohyoid muscles, thyroid cartilage, left and right vocal folds, left and right paraglottic spaces, left and right side arytenoid cartilages, and rima glottides. Concerning the evaluation of the videos amongst the investigators: they identified >80 % of vocal fold movement and the targeted anatomical structures except the arytenoid cartilages (only up to 63 %), having the sonography only. In combination with the laryngoscopy video-overlay, investigator detection rates significantly improved (>90 % of vocal fold movement, p < 0.001; >90 % in most anatomical structures, (p < 0,001). Laryngeal sonography is a helpful diagnostic tool to identify laryngeal structures and the movement of the vocal folds in children.

Value of high resolution ultrasonography in assessment of laryngeal lesions

OBJECTIVE

The aim of this study is to evaluate the value of high resolution ultrasonography (HRUS) in diagnosis of various laryngeal lesions which already diagnosed with rigid endoscopy.

STUDY DESIGN

Prospective study with control group.

PATIENTS AND METHODS

Sixty-six patients were suffering from throat symptoms and pre-examined by rigid endoscopy under local anesthesia and diagnosed to have a laryngeal lesion and 32 volunteers compose the control group. All 98 persons (patients and control groups) were examined by HRUS.

RESULTS

HRUS was helpful in describing various laryngeal lesions, vocal fold polyps (17) 25.7%, glottic cancer (6) 9.1%, epiglottic enlargement (2) 3.1% and one patient had laryngocele (1.5%). HRUS was highly significant in diagnosis of subglottic lesions (10) 15.2%. Also vocal fold mobility can be demonstrated by HRUS. While interarytenoid lesions (17) 25.8% and small laryngeal lesions as vocal fold nodules (13) 19.6% were difficult to be described.

CONCLUSION

Rigid endoscopy in laryngeal examination gives us large, bright image but it is difficult to diagnose patients with a sensitive gag reflex, patients with neck or jaw diseases or stridor and very difficult in infants and children. HRUS is an alternative method in diagnosis of some laryngeal lesions, and it is superior in the diagnosis of small subglottic lesions.

[Ultrasound of the larynx, hypopharynx and upper esophagus]

Sonography is an integral part of the routine diagnosis of diseases of the head and neck area. Ultrasound plays an important role in particular in the diagnosis, treatment and follow-up of head and neck cancer. Sonographic imaging of the larynx, hypopharynx and upper esophagus is often difficult due to the anatomical conditions. Therefore, CT and MRI are performed as the imaging techniques of first choice for diseases of these organs. In addition to the well-established transcutaneous ultrasound, endoscopic endoluminal ultrasound has developed as a promising new technique in recent years. Hollow organs can be displayed in high resolution transcutaneously and endoluminally. Thus, the attending otolaryngologist can use endoscopy and ultrasonography for accurate surgical planning. The aim of the present paper is to present the possibilities and limitations of ultrasonography of the larynx, hypopharynx and upper esophagus.

Anatomical landmarks for endosonography of the larynx

BACKGROUND

A precise knowledge of anatomy is necessary to allow a correct interpretation of sonographic images when investigating a particular region of the body. The objective of the present study was to establish anatomical landmarks for endosonography of the larynx.

METHODS

In an experimental study, a total of 32 normal human larynges were examined endosonographically, and the classical landmarks were correlated to horizontal whole-organ sections of the scanned specimens.

RESULTS

All laryngeal specimens showed a similar and reproducible sonoanatomy, which could be verified consistently on corresponding histological cross sections. Anatomical structures readily identified included the laryngeal framework, the vocal ligament, the vocal muscle, the ventricular fold, the preepiglottic and paraglottic space, and the epiglottis.

CONCLUSIONS

Due to a reproducible sonoanatomy of the larynx, endosonography might be an interesting complementary tool in the diagnostic investigation of laryngeal lesions such as medium-sized tumors, cysts, laryngoceles, and stenoses.

Dynamic B-mode ultrasound imaging of vocal fold vibration during phonation

We used B-mode imaging to study the vibratory phenomena of the vocal folds. The presence of multilayered structures of the vocal folds in the B-mode image was verified by using freshly excised human larynges in vitro. To capture images of vocal fold vibration, a special treatment was used to reconstruct the aliasing B-mode motion pictures of vocal fold vibration. Echo-particle image velocimetry (Echo-PIV) analysis was then applied to trace the tissue particles in the motion pictures. The vibratory behavior of the body (vocal ligament and muscle) of the vocal folds was revealed. Further analysis showed a quasi-longitudinal wave along the body of the vocal folds in the coronal plane. This is, to the best of our knowledge, the first time that vocal fold vibration physiology has been studied using B-mode imaging and Echo-PIV.

Non-invasive assessment of benign vocal folds lesions in children by means of ultrasonography

OBJECTIVES

Flexible fiberoptic endoscopes have made pediatric laryngeal examinations an everyday practice, even though fiberoptic-flexible laryngoscopy (FFL) is not always well tolerated in young children because of limited cooperation. Laryngeal ultrasonography (LUS) has been applied to normal and pathological findings in infants and children, allowing the assessment of subglottic hemangiomas, laryngeal stenosis and paralysis. No previous study assessed benign vocal folds lesions by LUS in children. The aim of this study is to evaluate the possibility of LUS to detect benign vocal fold lesions in children by comparing the results of FFL in 16 children with those of LUS.

METHODS

Sixteen children (9 males and 7 females) with a mean age of 7.5+/-4.0 years were included in the study. Each child underwent FFL performed by a skilled phoniatrician and LUS performed blindly by an expert radiologist.

RESULTS

On FFL bilateral vocal folds nodules were found in 9 patients, vocal fold cyst in 2 other patients, while in 2 children the vocal folds appeared normal. Laryngeal papyllomatosis, vocal fold polyp and vocal fold irregularity were found in only one patient. LUS enabled the diagnosis in all the 14 patients with vocal fold lesions. Bilateral hyperechoic lesions were visible in 10 patients, while hypoechoic lesions were found in three patients. No lesion were found in two children, while one patient presented with a monolateral hyperechoic lesion.

CONCLUSIONS

LUS was accurate, safe, well accepted and tolerated. LUS appears to be a useful diagnostic tool for supplementing FFL in the assessment of benign vocal fold lesions in children and may represent an interesting alternative in everyday clinical practice.

Advances in laryngeal imaging

Imaging and image analysis became an important issue in laryngeal diagnostics. Various techniques, such as videostroboscopy, videokymography, digital kymography, or ultrasonography are available and are used in research and clinical practice. This paper reviews recent advances in imaging for laryngeal diagnostics.

Using the patient's questionnaire data to screen laryngeal disorders

This paper is concerned with soft computing techniques for screening laryngeal disorders based on patient's questionnaire data. By applying the genetic search, the most important questionnaire statements are determined and a support vector machine (SVM) classifier is designed for categorizing the questionnaire data into the healthy, nodular and diffuse classes. To explore the obtained automated decisions, the curvilinear component analysis (CCA) in the space of decisions as well as questionnaire statements is applied. When testing the developed tools on the set of data collected from 180 patients, the classification accuracy of 85.0% was obtained. Bearing in mind the subjective nature of the data, the obtained classification accuracy is rather encouraging. The CCA allows obtaining ordered two-dimensional maps of the data in various spaces and facilitates the exploration of automated decisions provided by the system and determination of relevant groups of patients for various comparisons.

Technique of high-frequency endolaryngeal ultrasound

Objective:

We describe in detail the technique of in vivo endolaryngeal ultrasound during microlaryngoscopy, offering a number of practical suggestions which may be of use, especially to the otolaryngologist.

Methods:

Endosonography is a non-invasive imaging technology usually applied for the assessment of local tumour growth and regional lymph node metastases in the digestive tract.

Conclusions:

Due to a penetrating depth of up to 25 mm and a high tissue resolution, endosonography also qualifies for use in the larynx. The technique may have a potentially important role in the intra- and post-operative investigation of laryngeal lesions bigger than 3 mm.

Multiple feature sets based categorization of laryngeal images

This paper is concerned with an automated analysis of laryngeal images aiming to categorize the images into three decision classes, namely healthy, nodular, and diffuse. The problem is treated as an image analysis and classification task. Aiming to obtain a comprehensive description of laryngeal images, multiple feature sets exploiting information on image colour, texture, geometry, image intensity gradient direction, and frequency content are extracted. A separate support vector machine (SVM) is used to categorize features of each type into the decision classes. The final image categorization is then obtained based on the decisions provided by a committee of support vector machines. Bearing in mind a high similarity of the decision classes, the correct classification rate of over 94% obtained when testing the system on 785 laryngeal images recorded at the Department of Otolaryngology, Kaunas University of Medicine is rather promising.

ULTRASONOGRAPHY OF THE EQUINE LARYNX

Nasopharyngeal and laryngeal evaluation is important when examining horses with upper airway signs for poor performance. Currently endoscopy is the most common method to evaluate the equine upper airway. Ultrasonography of the equine larynx has not previously been described. Using six cadaveric specimens and four standing horses, the ultrasonographic appearance of the equine larynx was established. A scanning technique, including useful acoustic windows and the normal ultrasonographic appearance at each site, is described. Ultrasound allowed visualization of portions of the hyoid apparatus, laryngeal cartilages, associated soft tissues, and intrinsic and extrinsic laryngeal musculature, that are not seen using endoscopy. Additionally, real-time ultrasound allowed observation of the movement of the vocal folds and the arytenoid cartilages during respiration. In three horses with arytenoid chondritis, ultrasonography aided in the diagnosis and localization of arytenoid abcessation and perilaryngeal inflammation. The establishment of this technique will serve as the basis for future investigations in the evaluation of clinical patients with upper airway abnormalities.

Charakterisierung von Stimmlippen mittels optischer Kohärenztomographie

Optical coherence tomography (OCT) is a new, non-invasive method for investigating biological tissue, with a beam penetration of up to 3 mm. In this study, OCT was used on porcine and human larynxes. The porcine vocal folds were assigned to defined areas and examined by OCT followed by traditional histomorphological analysis. We were able to validate this new method by demonstrating that both OCT and the histological assays showed a clear demarcation of the epithelium mucosae from the deeper layers. OCT application to human vocal folds delivered same results. The current standard procedure for ensuring an accurate diagnosis if tissue is malignant, is still an invasive one. Our results show that OCT allows the collection of crucial information on the quality of morphological changes on a vocal fold without the necessity of being invasive. Thus, we propose that OCT be introduced as a new method for the detection of morphological changes in the vocal fold complementary to other established methods.