B-mode Ultrasound, Sono-Elastography, and Diffusion-weighted Imaging MRI in Thyroid Nodules

Comparative Study of B-mode Ultrasound, Sono-Elastography, and Diffusion-weighted Imaging MRI in the Characterization of Thyroid Nodules

To compare the accuracy of the conventional Ultrasound 'TI-RADS', US elastography, DWI MRI, and its ADC value in characterization and differentiation of thyroid nodules.

Thyroid nodules are one of the most common endocrine carcinomata (1) Most thyroid tumors have a good prognosis if early diagnosis and timely treated (2) An Ultrasound (US) exam is a safe, non-invasive imaging technique for detecting thyroid nodules (3) However, still there are no dependable criteria to discriminate malignant from benign lesions. (4) In 2009, Horvath et al proposed the Thyroid Imaging Report and Data System (TI-RADS). The new version of TI-RADS was launched by ACR in 2017. (5) Color Doppler ultrasound is also used to differentiate benign from malignant thyroid nodules. The presence of intra-nodular vascularity (Type 1b) was considered close to be malignant (6) US elastography is a novel tool to increase the diagnostic value of Ultrasound and as an adjuvant tool (7) Shear wave elastography evaluates elasticity through the propagation speed of shear waves, with the wave speed being faster in hard tissue (8) Conventional T1-and T2-weighted MR imaging can-not differentiate benign from malignant nodules (9) Diffusion-weighted imaging (DWI) is a non-invasive tool used to distinguish benign from malignant nodules (10). Malignant thyroid nodules usually have a lower ADC value attributed to cellular density and tissue perfusion. (11) Combining subjective MRI features with a quantitative measurement could improve the diagnostic yield of DW-MRI (12) The cytological examination by fine-needle aspiration (FNA) has become a reliable tool to diagnose thyroid cancers (2) Suspicious cytological findings reach up to 30% of all aspirated nodules, suggesting the need for less invasive methods (13)

Inclusion Criteria:

• Patients should have a normal bleeding profile.
• Presence of solitary or multiple nodules in the thyroid gland.
• In the case of patients having multiple nodules, the nodule having suspicious ultrasound features (having TI-RADS score 4 or 5) was selected for further analysis.
• The nodules were either solid or mixed (containing both solid and cystic parts) with a predominant solid component

Exclusion Criteria:

• Contraindicated biopsy (as thrombocytopenia or bleeding disorder).
• Patient with cystic and mainly cystic nodules (TI-RADS 1 nodules).
• Nodules with complete shell-calcification which may cause color mapping artifacts.
• MRI contraindications such as Claustrophobia, MR-incompatible pacemakers, and MR-incompatible prosthetic heart valves.
• Patients with recurrent thyroid masses.
• History of operative procedure, chemo, or radiotherapy on the thyroid gland.
• Declined consent.