Thymic cyst: Is attenuation artifactually increased on contrast-enhanced CT?

Area of Science:

• Radiology
• Medical Imaging
• Thoracic Imaging

Background:

• Thymic cysts are frequently misdiagnosed as thymomas or lymph nodes.
• This misdiagnosis can lead to unnecessary thymectomy procedures.

Purpose of the Study:

• To investigate the artifactual effect of adjacent large vessels on thymic cyst attenuation values.
• To analyze the impact on contrast-enhanced CT (CE-CT) findings.

Main Methods:

• Retrospective analysis of 84 patients with pathologically confirmed thymic cysts and preoperative CE-CT.
• Quantitative measurements of cyst size, attenuation, and adjacent large vessel attenuation.
• Classification into artifactual hyper-density, unchanged density, and artifactual hypo-density groups based on attenuation changes.

Main Results:

• Artifactual hyper-density was associated with smaller cyst diameter, higher postcontrast cyst attenuation, and lower nonenhanced adjacent vessel attenuation.
• Multivariable logistic regression identified factors influencing artifactual hyper-density.

Conclusions:

• Pseudo-enhancement of thymic cysts is more pronounced with higher adjacent large vessel attenuation on CE-CT.
• Understanding this artifactual hyper-density phenomenon can reduce preoperative misdiagnosis and unnecessary thymectomy.