"There is at least an 11.3% prevalence of malignant or potentially malignant lesions among incidental thyroid abnormalities detected on CT. Patients 35 years or younger who have incidental abnormalities have a significantly greater rate of malignancy. No CT feature reliably distinguishes benign from malignant lesions in the thyroid gland. CT underestimates the number of nodules relative to sonography, which suggests that sonography is a useful adjunctive test after the incidental detection of a thyroid abnormality on CT."
Significance of Incidental Thyroid Lesions Detected on CT: Correlation Among CT, Sonography, and Pathology
Shetty SK et al.
AJR 2006 Nov;187(5):1349-1356
- What CT findings of an incidental thyroid nodule are concerning?
- malignant nodules showed nodular or rim calcifications more frequently than benign nodules
- AP/T ratio of greater than 1.0 was more frequent in malignant nodules (anterior-posterior to transverse diameter measurements)
- higher mean attenuation value is more frequent in malignant nodules (>130 HU)
"The prevalence of incidental thyroid lesions in the general population seems to be high—approximately 10% to 40% in ultrasonography studies and 36% to 50% in autopsy series. Most of these lesions are benign; however the risk of malignancy ranges from 1.5% to 17% in incidentally detected lesions."
The Prevalence and Significance of Incidental Thyroid Nodules Identified on Computed Tomography
Yoon DY et al.
J Comput Assist Tomogr 2008;32:810-815
"We found at least 9.4% (15/160) prevalence of malignancy among incidental thyroid nodules detected on CT. The further evaluation with US or biopsy should be performed if an ITN shows CT features suggesting malignancy (calcification; AP/T ratio >1.0, or mean attenuation value >130 HU)."
The Prevalence and Significance of Incidental Thyroid Nodules Identified on Computed Tomography
Yoon DY et al.
J Comput Assist Tomogr 2008;32:810-815
- How do you manage the incidental thyroid nodule seen on a CT scan of the neck or chest?
- Mention it in the report but do not provide further guidance
- Advise clinical correlation
- Recommend ultrasound in all cases
- Ignore it
- All of the above at different times
"Four specific patterns were identified; spongiform configuration, cyst with colloid clot, giraffe pattern and diffuse hyper-echogenicity, which had 100% specificity for benignity. In our series identification of nodules with one of these four patterns could have obviated more than 60% of thyroid biopsies."
Pattern Recognition of Benign Nodules at Ultrasound of the Thyroid: Which Nodules Can Be Left Alone?
Bonavita JA et al
AJR 2009;193:207-213
"Recognition of specific morphologic patterns is an accurate method of identifying benign thyroid nodules that do not require cytologic evaluation. Use of this approach may substantially decrease the number of unnecessary biopsy procedures."
Pattern Recognition of Benign Nodules at Ultrasound of the Thyroid: Which Nodules Can Be Left Alone?
Bonavita JA et al
AJR 2009;193:207-213
- Thyroid Nodules: Some Facts
- Seen in up to 50% of the population in autopsy series
- Incidence of malignancy in thyroid nodule is 3-7%
- Increased incidence of discovery with modern imaging techniques
