Reducing unnecessary thyroid fine needle aspiration using ACR--TIRADS system

Expósito Mª Rosa Alhambra; Ana Barrera-Martín; Ángel Rebollo-Román; Pedro Segui-Azpilcueta; Gálvez-Moreno María Ángeles

doi:10.1530/endoabs.70.AEP969

Introduction: Thyroid ultrasound is the main technique to study this gland’s pathology. ACR TI-RADS system evaluates the malignancy risk in thyroid nodules according to their sonographic features and stablishes the size in which to perform fine needle aspiration (FNA) for its cytological study. Nodules diagnosed as Bethesda category 4 (B4) means are follicular neoplasms or suspicious for follicular neoplasms.

Aim: Determine the pathology diagnosis of B4 nodules and study associations among malignancy and ACR-TIRADS sonographic features.

Material and Methods: Retrospective study of thyroid nodules classified as B4 in FNA in our hospital between 2012 and 2018. Statistical analysis: SPSS v.22.0 (Student’s t-test to compare means and Squared Chi/Fisher to proportions).

Results: 162 nodules classified as B4 in FNA. Mean age: 54.07 ± 14.62 years. 75.3% Women. 2.6% nodules stratified as ACR TI-RADS 2 with mean longest diameter (MLD) of 35.25 cm. 23.9% ACR TI-RADS 3 with MLD of 31.94 mm, 66.5% ACR TI-RADS 4 with MLD of 30.19 mm and 7.1% ACR TI-RADS 5 with a MLD of 29.09 mm.


Composition		Echogenicity		Shape		Margin		Echogenic Foci
Feature	%	Feature	%	Feature	%	Feature	%	Feature	%
Cystic or almost completely cystic	0	Hyperechoic or isoechoic	24.5	Wider than tall	94.2	Smooth	93.5	None or large comet-tail artifacts	87.1
Spongiform	0	Hypoechoic	71.0	Taller than wide	5.8	Lobulated or irregular	6.5	Macro-calcifications	5.8
Mixed	3.9	Very-hipoechoic	4.5			Extra-thyroidal extension	0%	Peripheralcalcifications	1.3
Solid or almost completely solid	96.1							Punctate echogenic foci	5.8

29 (17.8%) nodules met standard malignancy criteria: 15 papillary thyroid carcinomas, 12 follicular thyroid carcinomas and 2 medullary carcinomas. If ACR TI-RADS had been strictly followed, 25.2% of FNA could have been avoided. Among nodules without FNA indication, 3 were malignant (2 papillary and 1 follicular carcinoma). Of those with FNA indication 24.5% were malignant. In our cohort, ACR TI-RADS system was of 88.8% (CI 95% 1.08–0.77) and specificity of 30.2% (CI 95% 0.38–0.21). Positive predictive value was 24% and negative predictive valuewas 91%.

Conclusions: FNA performed could have been reduced in our cohort if the decision had been taken upon the strict application of ACR TI-RADS system. Given the low rate of false negative nodules, ACR-TIRADS constitutes a good screening method to determine which nodules should undergo FNA.

Endocrine Abstracts

AEP969