An update on pharyngeal assessment by the modified barium swallow

Abstract

The modified barium swallow study (MBSS) is a diagnostic examination that visualizes the functional anatomy and physiology of the oral pharyngeal swallowing mechanism in real time. The MBSS, a videofluoroscopic imaging method, is indicated for patients with known or suspected oropharyngeal dysphagia and ideally involves the combined expertise of a radiologist and speech pathologist. The MBSS provides critical diagnostic insights that help in identifying and assessing the type and severity of physiological swallowing impairments, evaluating the safety of oral intake, testing the effectiveness of evidence-based interventions, and developing treatment plans. This manuscript aims to present an overview of MBSS standards from an interdisciplinary perspective, emphasizes key areas of best practices, and reviews the common morphologic abnormalities seen on MBSS exams.

Keywords: Dysphagia; Modified barium swallow; Swallowing.

Fig. 1

Select pharyngeal domain components including critical elements of airway protection such as laryngeal elevation and laryngeal vestibular closure (a), contraction of the tongue base and apposing pharyngeal constrictors (b), shortening and compression of the pharynx (c), and opening of the pharyngoesophageal sphincter (d)

Fig. 2

Lateral and AP images of the pharynx demonstrating typical anatomy encountered during a MBSS. a. Tongue base, b. Epiglottis, c. Vallecula containing a small amount of residual barium, d. Hyoid bone, e. Laryngeal vestibule coated in barium, consistent with laryngeal penetration, f. Piriform sinuses containing a small amount of residual barium, g. Vocal cords coated in barium, h. Barium coating the anterior aspect of the trachea, consistent with tracheal aspiration

Fig. 3

a Lateral image shows a cricopharyngeal bar (arrow) that narrows the cricopharyngeal junction by approximately 50%. b Lateral image shows a Zenker’s diverticulum (arrow) posterior and superior to the narrowed cricopharyngeus. c Oblique image shows a Killian–Jamieson diverticulum arising inferior to the cricopharyngeus and extending in an anterior and lateral fashion. d AP image demonstrates a thin cervical esophageal web (arrow). e Lateral image shows a post cricoid defect (arrow), a normal finding along the anterior aspect of the hypopharynx. f Large anterior cervical osteophytes (arrow heads) prevent inversion of the epiglottis (arrow)

Fig. 4

Abnormal prevertebral soft tissues on MBSS in 3 separate patients. A First patient, 1-day post-anterior cervical discectomy and fusion (ACDF) complaining of dysphagia. Prevertebral soft tissue thickening is present anterior to the fusion hardware (arrow). Laryngeal flash penetration is subtly present as well (arrowhead). On follow-up MBSS performed 6 days later (not shown), the soft tissue thickening had significantly decreased and no laryngeal penetration or aspiration was demonstrated. In the absence of an underlying fluid collection, prevertebral soft tissue swelling after ACDF will usually peak around 2–4 days and then gradually improves/decreases, resolves within 6 weeks. B Second patient complaining of neck pain and dysphagia, without recent surgical or trauma history. Prevertebral soft tissue thickening is present (arrow). Further clinical and imaging evaluation was recommended, which revealed discitis osteomyelitis due to methicillin-susceptible Staphylococcus aureus. C Third patient with history of asthma complaining of chest and neck pain, as well as dysphagia. Subtle linear lucency tracking along the prevertebral soft tissues (arrows), consistent with retropharyngeal emphysema. Chest radiograph demonstrated pneumomediastinum (not shown). Acknowledgement: Cases 2 and 3 are courtesy of Dr. Sarah Shaves, Eastern Virginia Medical School

Fig. 5

a Lateral image of a modified barium swallow demonstrates an irregular mass centered at the epiglottis and extending to the larynx which was later proven to be a squamous cell carcinoma (arrows). b This patient had a prior history of laryngeal squamous cell carcinoma and underwent total laryngectomy with free flap reconstruction. This AP image demonstrates an irregular stricture (arrow) along the right lateral aspect of the distal end of the neopharynx that was proven to be secondary to squamous cell carcinoma recurrence. c A band of scar tissue or “pseudoepiglottis” (arrow) at the tongue base after total laryngectomy. If the pseudoepiglottis impedes the flow of liquid and food, then it may lead to formation of a diverticulum proximal to it. Long segment benign stricture (dashed arrow) is also present throughout the neopharynx in this patient that was likely secondary to a post radiation stricture. d This patient had a history of laryngeal squamous cell carcinoma and underwent a total laryngectomy with free flap reconstruction. A TEP was placed for voice restoration (white arrow), and the patient subsequently complained of coughing upon swallowing. Black dashed arrow shows leakage of barium through the TEP resulting in tracheal aspiration