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 T1 -weighted image (T1 WI)-SPIR, axial T2 WI, axial T2 WI-STIR, coronal T2 WI-SPIR, diffusion-weighted imaging (DWI), axial and coronal gadolinium-enhanced T1 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, T2 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 T2 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.