Sialographic Analysis of Radioiodine-Associated Chronic Sialadenitis

Abstract

Objectives/hypothesis: To apply a novel sialography classification system to identify parotid and submandibular ductal findings following I-131 therapy and to assess correlates to dose and duration of symptoms.

Study design: Retrospective single-center case series.

Methods: Patients who underwent sialography between February 2008 and February 2019 after previously receiving I-131 treatment were identified via a retrospective chart review. Their sialograms were systematically evaluated and scored by applying the Iowa parotid sialogram scale to also include submandibular gland analysis.

Results: From 337 sialograms, 30 (five submandibular, 25 parotid) underwent analysis. Ductal stenosis was identified in all sialograms and was graded as moderate (>50%-75%) in 7/30 cases and severe (>75%) in 15/30 cases. The distal (main) duct was narrowed in 23/30 cases. No association was identified between degree of ductal stenosis and I-131 dose (P = .39), age (P = .81), or time from I-131 therapy to sialogram (P = .97).

Conclusions: The Iowa parotid sialogram scale was successfully applied to report abnormalities of the parotid and submandibular ductal system. The most common manifestation of I-131-associated sialadenitis was a severe stenosis within the distal salivary duct. No statistically significant association was found between degree of ductal stenosis and dose of I-131, age, or duration of symptoms.

Level of evidence: 4 Laryngoscope, 131:E1450-E1456, 2021.

Keywords: Sialography; parotid gland; radioactive iodine; sialadenitis; submandibular gland.

Figure 1:

Representative sialogram images under fluoroscopy of the left parotid gland in a patient who had previously underwent radioactive iodine therapy. (A) shows the initial cannulation of the left parotid duct without injection of dye. No calculi are visualized. Lateral (B) and antero-posterior (AP) (C) sialogram images after injection of 3 cc of Isoview-370 dye show a marked stenotic portion (>75% stenotic) of the distal parotid duct. Magnified AP view (D) demonstrates the intraglandular parotid ductules with an irregular contour and paucity of normal branching pattern. Lateral (E) and AP (F) sialogram images obtained after the patient was given a small amount of lemon juice to swish and expectorate demonstrate no significant washout of contrast, consistent with the significant distal obstruction.

Figure 2:

Radioactive iodine (I-131) dose (A), patient age (B), and time from I-131 therapy (C) stratified by severity of ductal stenosis via box-and-whisker plot.