Elastography of the thyroid nodule, cut-off points between benign and malignant lesions for strain, 2D shear wave real time and point shear wave: a correlation with pathology, ACR TIRADS and Alpha Score

Abstract

Objective: A prospective cross-sectional investigation of 170 thyroid nodules (TN) between January 2020 and December 2021 at Alpha Imagen was conducted to determine cut-off points (C/O) for elastography measurements and their diagnostic accuracy.

Methods: Nodules were categorized by ACR TI-RADS, Alpha Score (AS), and Bethesda; all were evaluated using 2D Shear Wave Real Time Elastography (RT-SWE), point Shear Wave (pSWE), and Strain Elastography (SE). Data was assessed with ROC curves, the Shapiro-Wilk test, T test, Chi-square test, and ANOVA.

Results: C/O were as follows: RTSWE Emax of 115kPa and 6.5 m/s, Emean of 47.5 kPa and 4.1 m/s, pSWE (average) of 52.4 kpa and 4.15 m/s; sensitivity of 81.2% and specificity of 57.6%, with a PPV of 72.4% and NPV of 70.0%. SE Value A had a C/O of 0.20%, with a sensitivity of 84%, specificity of 57%, PPV of 72.4% and NPP of 73.6%. The Strain Ratio nodule/tissue C/O was calculated as 2.69, with a sensitivity of 84%, specificity of 57%, PPV of 72.3%, and NPV of 73.5%. The RLBIndex quality control must be at least 92%; for pSWE, we suggest a mean interquartile ratio of ≤15.7% for kPa and 8.1% for m/s. The recommended depth is between 1.2 and 1.5 cm, and commonly used ROI boxes were 3x3 and 5x5mm.

Conclusion: 2D-SWE and pSWE with Emax and Emean demonstrated C/O with excellent diagnostic accuracy. To maximize the correct classification of TN, we suggest combining ACR TI-RADS and AS with any of the elastography measurements assessed here.

Keywords: 2D SWE; Alpha Score; RT SWE; TIRADS; pSWE; strain elastography; thyroid elastography; thyroid nodule.

Figure 1

(A) Nodule in the lower left third of the thyroid gland. ACR TI-RADS 4, AS high suspicion, diameter greater than 1.55 cm. (B, C) TE 2D-SWE Emean and Emax above the C/O both in kPa and m/s. (D) SE A value of 0.13% suspicious for malignancy, and SR nodule/muscle of 0.6, lower than expected, not useful. Cytopathology: Bethesda VI. Post-surgical result: Papillary Thyroid Carcinoma.

Figure 2

(A) Nodule in the left middle third of the thyroid gland, 1.38 cm in its largest diameter, ACR TI-RADS 4, AS high suspicion. (B–D), TE 2D-SWE Emean, Emax above the C/O, A value 0.11% suspicious for malignancy, SR nodule/muscle slightly elevated. (D) quality maps, homogeneous green hue (optimum), M-STB Index with 5 stars and RLB index with 94%, values ​​considered optimal. Bethesda VI result, post-surgical histopathology: Papillary Thyroid Carcinoma.

Figure 3

Nodule in the right middle third of the thyroid gland, ACR TI-RADS 3, AS low suspicion. (A, B) pSWE with values ​​below the C/O, observe the optimal MIQR values ​​for both kPa and m/s, 3x3 mm ROI box, 1.0 cm depth. (C, D) Emean in kPa, maximum scale 140 kPa, the C/O is slightly elevated, but not the values: E max kPa, E max m/s and E mean m/s that are below the C/O. (D) the maximum scale in m/s of 6.8 has been used, the quality maps M-STB Index with 5 stars and RLB index with 95% with optimal values ​​for obtaining the samples. Cytopathological result: Bethesda II, benign.

Figure 4

(A) nodule in the lower right third of the thyroid gland, maximum diameter 2.0 cm, ACR TI-RADS 4. (B) peripheral Doppler vascularization, AS moderate suspicion. (C) maximum scale of 180kPa, TE 2D-SWE Emean and Emax with kPa below C/O. (D) pSWE kPa below C/O, MIQR 16%, ROI box 3 x 3 mm, depth 1.6 cm. Result: cytopathological Bethesda: II, benign.

Figure 5

(A), nodule in the left middle third of the thyroid gland, diameter greater than 1.6 cm, peripheral vascularization, ACR TI-RADS 4, AS moderate suspicion. (B) SE with ROI B of 3 mm, SR Nodule/Tissue of 1.14 under the C/O and Value A of 0.23% not suspicious. (C) 2D-SWE, full scale 5.8 m/s, Emean 3.5 and Emax 6.1 cm/s below C/O. (D) pSWE slightly above C/O, 52.8 kPa average, 57.4 kPa median, unreliable values ​​by the MIQR of 25% above the recommended value (15% for kPa), depth also at the maximum limit 1.53 cm. Cytopathological result: Bethesda II, benign.

Figure 6

(A) nodule on the right upper third and middle of the thyroid gland, diameter 2.1 cm; ACR TI-RADS 5 and AS high suspicion. (B) SE with SR Nodule/Tissue of 5.7 above the C/O and value A of 0.12%, suspicious of malignancy. (C) 2D-SWE Emean 95.4 and Emax 300 Kpa, above C/O. (D) pSWE with 118 kPa (average) and 113 kPa (median), above the C/O, with a good MIQR of 14% and a good depth of 1.19 cm. Cytopathological result: Bethesda V, post-surgical result Papillary Thyroid Carcinoma.