Review of Society of Radiologists in US (SRU) guidelines 2005
Note: The updated and peer-reviewed version of this resource is now available for download after registration on the MedEDPORTAL website. The link is below:
https://www.mededportal.org/publication/8467
BACKGROUND
Compared to other specialties, diagnostic radiology has few management guidelines. Examples of published guidelines include BI-RADS for breast imaging, management of incidental pulmonary nodules, management of ovarian cysts, and management of thyroid nodules.
In early 2010, we conducted a local quality analysis project and nation-wide survey that demonstrated that radiologists often do not follow published guidelines for reporting thyroid nodules, risking litigation and negative patient outcomes.
REVIEW OF GUIDELINES
The Society of Radiologists in Ultrasound (SRU) published a consensus statement in 2005 in Radiology that recommended when fine needle aspiration (FNA) should be considered for thyroid nodules detected by ultrasound (US). These guidelines were recently reviewed and compared to the American Thyroid Association guidelines in the SRU newsletter in 2010. Recommendations for FNA are based on three primary features:
1. Size
2. Composition (solid, cystic, or mixed)
3. Calcifications
The presence of cervical lymphadenopathy trumps nodule features and warrants biopsy, either of the lymph node or any suspicious nodule in the thyroid. Growth demonstrated by follow up also warrants biopsy, regardless of features. Vascularity demonstrated by Doppler ultrasound should be considered a problem solving tool, but is not included among primary features. Internal vascularity is more suspicious than peripheral vascularity.
Our goal is to demonstrate the ease of applying SRU guidelines to make thyroid US interpretation objective (and less subjective for the radiologist), to help radiologists gain experience in thyroid nodule interpretation, and to improve patient management. Criteria are reproduced below.
Society of Radiologists in Ultrasound
|
Ultrasound feature of thyroid nodule * |
Recommendation |
|
Microcalcifications |
Strongly consider FNA if ≥ 1 cm |
|
Solid or coarse calcifications |
Strongly consider FNA if ≥ 1.5 cm |
|
Mixed solid and cystic or almost entirely cystic with solid mural component |
Consider FNA if ≥ 2 cm |
|
None of above, but substantial growth compared to prior US |
Consider FNA |
|
Almost entirely cystic, none of above criteria, and no growth |
FNA probably unnecessary |
*Suspicious lymphadenopathy overrides nodule features and should prompt FNA of either the lymph node or the thyroid nodule. Internal vascularity increases the likelihood of malignancy.
Reference: Frates MC, Benson CB, Charboneau JW, et al. Management of Thyroid Nodules Detected at US: Society of Radiologists in Ultrasound Consensus Conference Statement. Radiology 2005;237:794-800.
Note that these guidelines simplify management:
1. The recommendation of the radiologist becomes simple – FNA, yes or no.
2. The table may be used as an algorithm, starting at the top. If a nodule contains microcalcifications and ≥ 1 cm, there is no need to debate about whether it is solid. If a nodule is solid and ≥ 1.5 cm, there is no need to analyze the vascularity, and so on. If a nodule can pass through the table without meeting any criteria, it escapes FNA.
Addressing the choices in the pre-test:
1. There is no role for thyroid scintigraphy in these recommendations. The need for scintigraphy is determined by the clinician based on symptoms and laboratory tests such as TSH.
2. There is no recommendation for follow up. In our experience, follow up depends on multiple factors, including patient age, risk factors, and local clinician preference