Diagnostic imaging of piriform sinus fistulas

To establish the usefulness of ultrasound, computed tomography (CT), magnetic resonance imaging (MRI) and barium contrast swallow studies in the diagnosis of piriform sinus fistulas (PSF). We reviewed the clinical histories and imaging studies of four pediatric patients diagnosed with PSF. Cervical ultrasound was the first imaging study performed in all cases. Three patients subsequently underwent intravenous contrast-enhanced CT examination and one underwent MRI. Barium contrast swallow studies were performed in all patients at a later time. All cases were confirmed at surgery. Ultrasound enabled the lesions to be located on the left side and showed the existence of heterogeneous collections in and around the thyroid glands in all four patients. Posterior CT and MRI studies determined the exact size of the abscessed lesions. Barium contrast swallow studies demonstrated the existence of the PSF in all four cases. The presence of a recurrent inflammatory process and acute suppurating thyroiditis located on the left side should raise suspicions of PSF. Both CT and MRI are useful in the study of PSF; however, in our experience, ultrasound examination is the technique of choice for initial evaluation and follow-up. After the acute process, barium swallow studies continue to be the main method for diagnosing the trajectory of the fistulous tract.