Imaging studies in sixty patients with acute suppurative thyroiditis.

Area of Science:

• Radiology
• Otolaryngology
• Endocrinology

Background:

• Pyriform sinus fistulae are the primary cause of infection in acute suppurative thyroiditis (AST).
• Limited reports exist on imaging findings in AST.
• This study aims to clarify imaging features for improved diagnosis and treatment.

Purpose of the Study:

• To review and elucidate the imaging features of acute suppurative thyroiditis (AST) based on ultrasonography (US), computed tomography (CT), and barium swallow studies.
• To differentiate AST from subacute thyroiditis using imaging.
• To identify the most effective imaging modality for detecting pyriform sinus fistulae.

Main Methods:

• Retrospective review of US, CT, and barium swallow studies from 60 AST patients with pyriform sinus fistulae (1998-2008).
• Analysis of imaging findings during acute, early, and late inflammatory stages of AST.
• Comparison of imaging features between AST and subacute thyroiditis.

Main Results:

• In the acute stage, US showed hypoechoic lesions and abscesses; CT revealed anatomical involvement and edema.
• Early-stage AST imaging can be mistaken for subacute thyroiditis due to unclear or nonspecific findings.
• Characteristic US findings for AST include perithyroidal hypoechoic space, effaced tissue planes, and unifocal lesions, differentiating it from multifocal/bilateral subacute thyroiditis.
• Barium swallow studies are superior to US and CT for detecting pyriform sinus fistulae.

Conclusions:

• US and CT effectively show inflammatory processes in AST, with CT offering better anatomical detail.
• Early inflammatory stage imaging may lead to misdiagnosis of subacute thyroiditis.
• Careful US evaluation can suggest AST, with barium swallow or fine-needle aspiration confirming the diagnosis.