Table 3.

Sensitivity, specificity and accuracy of CT and MRI for extrathyroid invasion

	CT (%)	CT criteria[38]	MRI (%)	MRI criteria
Trachea
Sensitivity	59	One of: ≥180° circumferential contact Lumen deformity Mucosal abnormality	100	One of: ≥180° circumferential contact Soft tissue signal in cartilage Intraluminal mass[36]
Specificity	91		84
Accuracy	83		90
Esophagus
Sensitivity	29	≥180° circumferential contact OR	82	Outer layer invasion[37]
Specificity	96	Abnormal wall or lumen	94
Accuracy	91		91
Recurrent laryngeal nerve
Sensitivity	78	2 of the following: Effaced fatty tissue in tracheoesophageal groove >25% of tumor abutting posterior portion of thyroid Signs of ipsilateral vocal cord palsy	94	Effaced fatty tissue in tracheoesophageal groove on at least one axial image[35]
Specificity	90		82
Accuracy	86		88
Carotid artery
Sensitivity	75	≥180° circumferential contact	100	≥270° circumferential encasement[41]
Specificity	99		88
Accuracy	99		91
Internal jugular vein
Sensitivity	33	≥180° circumferential contact
Specificity	99
Accuracy	97