Ultrasound Imaging and TIRADS Classification in Thyroid Nodules

MANAGEMENT OF THYROID NODULES : HOW TO MAKE A GOOD DIAGNOSIS ? 
Live Webinar, September 19th 2026
Ultrasound Imaging and TIRADS Classification in Thyroid Nodules
Achmad Fachri, MD
Head and Neck Department 
Dharmais National Cancer Center Hospital

Outline
Overview
What is US imaging ?
Why US ?
Anatomy Thyroid
TIRADS

Overview

Common Finding
Thyroid nodules are frequently encountered during routine ultrasonography in healthy adults.

Malignancy Risk
Majority are benign, but carry a 7–15% risk of malignancy requiring careful evaluation.

What is general US imaging?
US imaging  sonography  involves exposing part ot the body to high frequency sound waves  produce images

US examination do not use ionizing radiation (as used in x-rays).

US images are captured in real-time  show the structure and movement of the body’s internal organs  as well as blood flowing through blood vessels

Principles of US
Optimum frequency range for diagnostic  1-20 MHz.
3,5-5 MHz	:  abdominal, heart
5-10 MHz	:  thyroid, carotid, breast, testis, and other superficial tissues, infants.
10-15 MHz	:   for the eye

Ultrasound parts
Transducer

Image Optimization
Depth
Focus
TGC (to obtain a smooth grey-scale picture)
Zoom / magnification
Gain
Harmonic imaging  High contrast, high spatial resolution and low noise

Benefits
Mostly noninvasive
Widely available, easy to use and less expensive (relative)
Does not use ionizing radiation
Gives clear soft tissues image better than x ray
Real-time imaging  guide biopsies
Limitations
Operator dependent
US waves are disrupted by air / gas  not ideal imaging technique for bowel / organs obscured by the bowel
Large patients  Low image quality ec greater amounts of tissue attenuates (weakens) the sound waves
Difficulty penetrating bone

Anatomy Thyroid gland
Endocrine organ  thyroid hormone production. 
Enveloped by the pretracheal fascia
Extend from C5 to T1  anterior to thyroid and cricoic cartilages of larynx
Butterfly or "H"-shaped  two lobes (each +/- 4 cm in length)  connected by Isthmus. 
Arterial supply
A. Superior thyroid ( from External carotid)
A. Inferior thyroid ( from Thyrocervical trunk)
Venous drainage
Superior and Middle thyroid ( to Internal jugular vein)
Inferior thyroid ( to brachiosefalic vein)

ACR TI-RADS: Basic Principles
Goal: Improve the consistency of thyroid nodule evaluation and classification on ultrasound.

Provides specific management recommendations for each thyroid nodule.

Nodules are assessed  5 sonographic feature categories:
Composition
Echogenicity
Shape
Margin
Echogenic foci
Each feature is assigned 0–3 points according to its association with malignancy risk.

Total score → TR category (TR1–TR5) → management recommendation (follow-up or FNA).

Why We Need Risk Stratification
The Scope of the Problem
Thyroid nodules are found in as many as 68% of high-resolution ultrasound scans — making them one of the most common incidental findings in radiology practice.
Without a consistent framework, management decisions become arbitrary and patients face unnecessary procedures or inadequate follow-up.
A Fragmented Landscape
Over the past two decades, professional organizations worldwide developed a multitude of independent risk stratification systems (RSSs) — each yielding different management recommendations for identical nodules.
The result: confusion for practitioners and patients alike, and wide variation in biopsy rates across institutions.

ACR TI-RADS: The Points-Based Approach
Why Points-Based?
Ensures every nodule receives a classification.

By contrast, ATA guidelines left 13.9% of nodules unclassifiable, while K-TIRADS left 3.9% unclassified. ACR TI-RADS eliminates this gap entirely.

Five risk tiers (TR1–TR5) map directly to clear FNA and surveillance thresholds, reducing ambiguity at the point of care.

Key Advantage: Higher Size Thresholds

The Evidence Base
Thyroid cancer carries a 10-year relative survival of 99.4% for tumors smaller than 3 cm. 
Mortality does not exceed baseline until tumors surpass 2.5 cm.

Larger Biopsy Cutoffs
ACR TI-RADS sets the TR3 FNA threshold at 2.5 cm — compared to 1.5 cm under ATA guidelines — directly reflecting this survival data.

Biopsy Reduction
Grani et al.: The higher thresholds translate to a 19.9–46.5% reduction in unnecessary biopsies compared to other leading risk stratification systems, with the lowest false-negative rate (2.2%)

Evidence: Biopsy Reduction Across Studies
ACR Registry: 32,746 Nodules
In the largest comparative analysis, ACR TI-RADS recommended biopsy in only 26% of nodules — half the rate of ATA guidelines (51%) and K-TIRADS (50%).
Grani et al. (502 Nodules)
ACR TI-RADS achieved the lowest benign biopsy rate at 43.8%, versus 54.7% for ATA, 68.0% for EU-TIRADS, and 82.2% for K-TIRADS — reducing unnecessary procedures by 17.1–53.4%.

Mixed cystic-solid (1)
Isoechoic (1)
Comet tail artifact (0)

TI-RADS 2
No FNA or follow up

Mixed cystic-solid (1)
hypoechoic (3)

TI-RADS 3
FNA at 2.5 cm and 
follow up at 1.5 cm

Back wall of cyst
Cystic region

Mixed cystic-solid (1)
Isoechoic (1)
Lobulated margin (2)

TI-RADS 4
FNA at 1,5 cm and 
follow up at 1.0 cm

Solid (2)
Isoechoic (1)

TI-RADS 3
FNA at 2.5 cm and 
follow up at 1.5 cm

Safety: Will We Miss Cancers?
The Core Concern
Reducing biopsies raises the legitimate question: are we deferring diagnosis of clinically significant malignancies?
The Built-In Safety Net
ACR TI-RADS includes explicit follow-up recommendations for all nodules that do not meet FNA thresholds. Surveillance is a proven safe strategy for small suspicious nodules and even diagnosed small papillary thyroid cancers, given their indolent biology.
The Numbers
68.2% of malignancies received biopsy recommendations. An additional 21% were captured through surveillance monitoring — yielding a combined detection pathway of 89.2% of malignancies addressed under the protocol.

The Interobserver Variability Challenge
Structured Reporting Is Not Enough
Despite the explicit points-based framework, a study of 100 nodules interpreted by eight radiologists revealed only moderate agreement for management decisions (κ = 0.51).
Biopsy rates across seven different practices using ACR TI-RADS ranged from 4% to 35% — a nine-fold spread that underscores how much interpretation varies in real-world settings.
The Weakest Links

Margin
κ = 0.25–0.39
Fair agreement only

Echogenic Foci
κ = 0.25–0.39
Most consequential feature

Management
κ = 0.51
Moderate overall

Sources of Variability: Artifacts & Technique
Comet Tail Artifacts
Large comet tail artifacts — or high-echogenicity foci from the back wall of tiny cysts — are frequently misread as punctate echogenic foci (PEF). Since PEF carry 3 points, this single misclassification can elevate a TR2 nodule to TR4, triggering biopsy.
Scanning Parameters
Gain settings, transducer frequency, and post-processing compression significantly affect feature conspicuity. The same nodule can appear differently depending on equipment and operator technique — before interpretation even begins.
Training & Experience
Reader expertise matters. Training sessions and consensus discussions demonstrably improve feature assignment accuracy and reduce inter-reader discordance across institutions.

Future Directions: Emerging Technologies
Each technology addresses a distinct limitation of conventional B-mode ultrasound. Elastography offers reproducible stiffness quantification (sensitivity 75–89% in meta-analyses), contrast-enhanced ultrasound interrogates tumor vascularity, and AI-driven point optimization has already demonstrated accuracy gains beyond unmodified ACR TI-RADS — though adoption barriers of time, cost, and regulatory approval remain.
Elastography
Contrast‑Enhanced US
Artificial Intelligence

MANAGEMENT OF THYROID NODULES : 
HOW TO MAKE A GOOD DIAGNOSIS ? 
Live Webinar, September 19th 2026
Thank You

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