Objective To compare the diagnostic efficacy of computer-aided diagnosis（CAD）system based on different guidelines for the diagnosis of benign and malignant thyroid nodules.Methods A multicentric prospective study was conducted in 453 patients with 521 thyroid nodules

which were confirmed by pathology of surgery or ultrasound guided fine needle aspiration.Taken pathology as the gold standard

the receiver operating characteristic（ROC）curve of CAD system was obtained based on different guidelines（ACR guideline

ATA guideline

AACE guideline

KSThR consensus

BTA guideline

Kwak guideline

Seo guideline

Russ guideline）.The area under the curves（AUC）was calculated and the diagnostic efficiency was analyzed.Results When the cut-off value was 2 scores

the sensitivity

negative predictive value and AUC of KSThR consensus were 90.60%

84.1% and 0.759

respectively

which were higher than those of the other seven guidelines（all P<0.01）.When the cut-off value was grade 4

the specificity and positive predictive value of BTA guidelines in the diagnosis of thyroid malignant nodules were 79.95% and 70.9%

respectively

which were higher than the other seven guidelines（all P<0.01）.Conclusion The diagnostic efficay of CAD system in the diagnosis of benign and malignant thyroid nodules is satisfying.The KSThR consensus has the highest AUC and sensitivity

and the BTA guidelines has the highest specificity.