MRI in Children With Pyriform Sinus Fistula.

Background: A variety of imaging modalities have been described for the diagnosis of congenital pyriform sinus fistula (CPSF). To date, there have been few MRI reports.

Purpose: To evaluate MRI findings of CPSF and interobserver reliability.

Study Type: Retrospective.

Population: In all, 115 patients aged 23 days to 15.4 years at operation.

Field Strength/sequence: 3.0T/axial T -weighted image (T WI)-SPIR, axial T WI, axial T WI-STIR, coronal T WI-SPIR, diffusion-weighted imaging (DWI), axial and coronal gadolinium-enhanced T WI-SPIR.

Assessment: For each patient, the medical records, including demographics, clinical manifestations, and MRI findings were reviewed. All the MRI studies were interpreted by three radiologists independently.

Statistical Test: Kendall's W test was made to determine the interobserver reliability of three reviewers for MRI findings.

Results: CPSF occurred on the left side in 104 (90.4%) patients and on the right side in 11 (9.6%) patients. The male-to-female ratio was 59:56. The age at first episode varied from birth to 12.3 years. There was one neonate patient, who presented with a unilocular cystic mass in the left neck. A tunnel-like lesion between the pyriform fossa and the upper pole of the thyroid gland, T high signal behind the cricothyroid joint, thyroid gland involvement, deep neck abscesses or masses were noted in 46 (40%), 93 (80.9%), 96 (83.5%), and 36 (31.3%) patients, respectively. There was excellent interobserver reliability for all the MRI findings, ranging from 0.84 to 1.00.

Data Conclusion: The sinus tract presenting with a tunnel-like lesion goes behind the cricothyroid joint in most cases. For patients presenting with acute suppurative thyroiditis (AST) or neck infection with thyroid gland involvement, the presence of T high signal behind the cricothyroid joint highly suggests the diagnosis of CPSF. MRI is a reliable method for the diagnosis of CPSF.

Level Of Evidence: 4 TECHNICAL EFFICACY STAGE: 2.