Comparison of Various Ultrasound-Based Malignant Risk Stratification Systems on an Occasion for Assessing Thyroid Nodules in Hashimoto’s Thyroiditis

Figures & data

Figure 1 Flowchart of the study.

Abbreviations: BSRTC, Bethesda System for Reporting Thyroid Cytology; US, ultrasound; US-FNA, ultrasound-guided fine-needle aspiration; FNA, fine-needle aspiration.

Figure 2 The ultrasound images of four thyroid nodules with or without HT. (A) Benign nodule without HT, solid, hyperechoic, wider than tall shape, smooth margin, no echogenic foci; (B) Benign nodule with HT, almost completely solid, isoechoic, wider than tall shape, smooth margin, no echogenic foci; (C) Malignant nodule without HT, solid, hypoechoic, taller than wide shape, smooth margin, macro-calcifications; (D) Malignant nodule with HT, solid, hypoechoic, taller than wide shape, irregular margin, no echogenic foci.

Abbreviation: HT, Hashimoto’s thyroiditis.

Table 1 Clinical Characteristics of the Study Population

	Total		HT		Non-HT
	Malignant	Benign	Malignant	Benign	Malignant	Benign
Number of patients	406	288	154	61	252	227
Number of nodules	426	290	161	62	265	228
Sex (men/women)	76/350	55/235	13/148	4/58	63/202	51/177
Age	44.29±12.46	49.9±12.40**	42.44±12.11	49.2±13.15**	45.41±12.57	50.10±12.21**
TT3 (ug/L)	1.10±0.20	1.09±0.21	1.09±0.19	1.04±0.20	1.10±0.21	1.10±0.21
TT4 (ug/L)	83.44±18.54	87.76±19.65**	81.70±17.76	84.59±18.42	84.53±18.97	88.69±19.94*
FT3 (pmol/L)	4.82±0.57	4.76±0.56	4.81±0.60	4.67±0.48	4.82±0.55	4.78±0.58
FT4 (pmol/L)	17.15±2.67	17.31±2.31	16.68±2.54	17.13±2.13	17.44±2.71	17.36±2.36
TSH (mIU/L)	2.39±2.47	1.91±1.33**	3.05±3.54	2.67±1.76	1.96±1.26	1.69±1.09*
TgAb (kU/L)	39.2(23.3, 128.5)	34.0 (23.0,62.0)*	144.0(60.0, 280.0)	170.9(63.4, 299.3)	27.3(18.9,39.6)	29.4(21.5,40.4)
TPOAb (kU/L)	37.2(28.0, 238.6)	33.9 (28.0,54.4)**	525.7(78.4, 1300.0)	579.1(47.4, 1300.0)	28.8(28.0,38.2)	30.0(28.0,40.8)

Notes: Data were expressed as mean ± standard deviation for normal distribution, and as median (interquartile range 25–75%) for skewed variables. *P<0.05, **P<0.01 vs patients with malignant nodules.

Abbreviations: TT3, total triiodothyronine; TT4, total thyroxine; FT3, free triiodothyronine; FT4, free thyroxine; TSH, thyroid-stimulating hormone; TgAb, thyroglobulin antibody; TPOAb, thyroid peroxidase antibody; HT, Hashimoto’s thyroiditis.

Table 2 The Malignancy Rates of Various Categories of the ATA, ACR and KSThR Guidelines

	Malignant		Benign		Recommended Malignancy Risk (%)	Calculated Malignancy Risk (%)		Ptrend
	HT	Non-HT	HT	Non-HT		HT	Non-HT	HT	Non-HT
ATA guidelines								<0.001	<0.001
High suspicion	124	217	17	57	>70–90	87.9	79.2*
Intermediate suspicion	35	41	26	97	10–20	57.4	35.3**
Low suspicion	1	3	12	48	5–10	7.7	5.9
Very low suspicion	0	0	6	19	<3	0	0
Benign	0	0	0	0	<1	0	0
ACR guidelines								<0.001	<0.001
Highly Suspicious	105	195	11	40	>20	90.5	83.0
Moderately Suspicious	55	67	35	130	5–20	61.1	34.0**
Mildly Suspicious	1	3	12	44	5	7.7	6.4
Not Suspicious	0	0	3	10	<2	0	0
Benign	0	0	1	4	<2	0	0
KSThR guidelines								<0.001	<0.001
High suspicion	119	210	15	52	>60	88.8	80.2*
Intermediate suspicion	41	52	29	108	15–50	58.6	32.5**
Low suspicion	1	3	17	64	3–15	5.6	4.5
Benign	0	0	1	4	<3	0	0

Notes: Data were showed as number of nodules. *P_trend <0.05, **P_trend <0.01 vs patients with Hashimoto’s thyroiditis.

Abbreviations: ATA, American Thyroid Association; ACR, American College of Radiology; KSThR, Korean Society of Thyroid Radiology; HT, Hashimoto’s thyroiditis.

Table 3 The Diagnostic Performance of the ATA, ACR and KSThR Guidelines in Detecting Malignant Thyroid Nodules

Guidelines	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)
HT
ATA guidelines	77.5(70.1–83.6)	72.1(59.0–82.5)	87.9(81.1–92.6)	55.0(43.5–66.0)
ACR guidelines	65.2(57.3–72.4)**	82.3(70.1–90.4)*	90.5(83.3–94.9)	47.7(40.0–57.5)
KSThR guidelines	73.9(66.3–80.4)^##	75.8(63.0–85.4)	88.8(81.9–93.4)	52.8(42.0–63.4)
Non-HT
ATA guidelines	83.1(77.9–87.4)	74.2(67.8–79.7)	79.2(73.8–83.7)	78.8(72.5–84.1)
ACR guidelines	73.6(67.8–78.7)**	82.5(76.8–87.0)**	83.0(77.4–87.4)	72.9(66.9–78.1)
KSThR guidelines	79.2(73.8–83.9)*^##	77.2(71.1–82.4)^##	80.2(74.7–84.7)	76.2(70.1–81.4)

Notes: *P<0.05, **P<0.01 vs the ATA guidelines; ^##P<0.01 vs the ACR guidelines.

Abbreviations: PPV, positive predictive value; NPV, negative predictive value; ATA, American Thyroid Association; ACR, American College of Radiology; KSThR, Korean Society of Thyroid Radiology; HT, Hashimoto’s thyroiditis.

Table 4 Comparison of Unnecessary FNA Rates for the Diagnosis of Thyroid Cancer (≥1cm)

Guidelines	No. of Nodules Indicated for FNAs		No. of Malignant Nodules Among the FNAs		No. of Benign Nodules Among the FNAs		Unnecessary FNA Rate (%)
	HT	Non-HT	HT	Non-HT	HT	Non-HT	HT	Non-HT
ATA guidelines	68	178	41	60	27	118	37.5	59.0**
High suspicion	40	72	36	47	4	25
Intermediate suspicion	16	60	5	12	11	48
Low suspicion	8	34	0	1	8	33
Very low suspicion	4	12	0	0	4	12
Benign	0	0	0	0	0	0
ACR guidelines	47	120	34	44	13	76	18.1	38.0**
Highly Suspicious	31	51	30	38	1	13
Moderately Suspicious	15	46	4	6	11	40
Mildly Suspicious	1	23	0	0	1	23
Not Suspicious	0	0	0	0	0	0
Benign	0	0	0	0	0	0
KSThR guidelines	70	187	41	61	29	126	40.3	63.0**
High suspicion	34	66	32	45	2	21
Intermediate suspicion	23	71	9	15	14	56
Low suspicion	12	49	0	1	12	48
Benign	1	1	0	0	1	1

Notes: Data were showed as number of nodules. **P<0.01 vs patients with Hashimoto’s thyroiditis.

Abbreviations: FNA, fine-needle aspiration; ATA, American Thyroid Association; ACR, American College of Radiology; KSThR, Korean Society of Thyroid Radiology; HT, Hashimoto’s thyroiditis.