Triple-phase contrast-enhanced computed tomography findings for feline cranial mediastinal tumors: Pilot study.

OBJECTIVE

Thymoma and mediastinal lymphoma (ML) are the most common cranial mediastinal masses in cats. Considering differences in treatment and prognosis, accurate antemortem diagnosis is essential. However, fine-needle aspiration can be inconclusive. Computed tomography (CT) is often used as a diagnostic tool, though apparently no previous studies have directly compared CT findings for thymoma and ML. This pilot study was a preliminary investigation of using CT to differentiate thymoma from ML in cats.

ANIMALS AND PROCEDURE: Six cats diagnosed with either thymoma or ML underwent triple-phase contrast-enhanced CT. Parameters assessed included changes in CT attenuation across contrast phases and enhancement patterns.

RESULTS

Thymomas exhibited peak enhancement during the equilibrium phase with heterogeneous contrast patterns, whereas MLs enhanced rapidly in the arterial phase and peaked in the venous phase with homogeneous contrast distribution.

CONCLUSION AND CLINICAL RELEVANCE: We suggest that the contrast-enhancement patterns and variations in CT values in triple-phase contrast-enhanced CT scans may be key to differential diagnosis of thymoma versus ML in cats. However, this pilot study had a small sample size and the objective of proposing hypotheses. Large-scale studies are needed to test this hypothesis.