Sonography of the Thyroid Gland

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Sonography of the Thyroid Gland
Nagesh Ragavendra, M.D. Professor of
Radiology Department of Radiological
Sciences David Geffen School of Medicine at UCLA
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Thyroid Imaging Techniques

• CT MRI
• No functional information. NO role in
  evaluation of thyroid structure. Tumor staging
• Ultrasound
• Modality of choice for evaluation of thyroid
  structure No functional information
• Isotope PET
• Functional information Limited structural
  information

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Sonography

• Noninvasive medical imaging
• High frequency sound waves (ultrasound)
• Visualize internal body structures

Utility

• Diagnosis
• Biopsy Guidance
• Treatment Planning
• OR - Tumor Localization

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SONAR Sound Navigation and Ranging

• Speed of Sound in Water
• 1540 m/sec gt Known
• Distance gt gtgtgtCalculated

Echo Brightness gtgtgt Intensity B Mode
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Sonography
Advantages Disadvantages

• No Radiation
• No IV Injection
• Portable
• Painless

• Operator Dependence
• Bone, air/gas
• Obesity

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Real Time Ultrasound Scanner
Linear Sector Transducers
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Liver
Trachea
Kidney
Diaphragm
Transverse View Thyroid Gland
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Transducer Linear

• Clinical Uses
• Superficial Structures
• Thyroid
• Parathyroid
• Breast
• Testes

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Transducer Sector

• Clinical Uses
• Deeper Structures
• Liver
• Pancreas
• Uterus
• Ovary

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Transducer Frequency Typical 3 MHz 12 MHz

Trade-off
Depth of Penetration High frequency gtgt
Shallow Low Frequency gtgt Deep
Resolution High Frequency gtgt Higher Low
Frequency gtgt Poorer
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Patient Positioning
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Anatomic Scanning Planes
Sagittal (Longitudinal)
Transverse
Coronal
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Thyroid Anatomy
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Thyroid Anatomy
Esophagus
Longus
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Thyroid Nodule Characterization
Solid
Complex
Cyst

• Characteristics of a Cyst
• Echo free center
• Smooth back wall
• Acoustic enhancement

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• Characteristics of a Solid Nodule
• Many echo reflections
• Back wall indistinct
• No acoustic enhancement

• Characteristics of a Complex Nodule
• Cyst Solid Features Combined

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• Characteristics of a Cyst
• Echo free center
• Smooth back wall
• Acoustic enhancement

Longitudinal Right Lobe
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• Characteristics of a Solid Nodule
• Many echo reflections
• Back wall indistinct
• No acoustic enhancement

Longitudinal Right Lobe
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Characteristics of a Complex Nodule Cyst Solid
Features Combined
Longitudinal Right Lobe
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Hypoechoic Isoechoic Hyperechoi
c
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1 cm
Shape
Typical features of a malignant thyroid nodule
Micro-calcification
0.6 cm
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Dec 2005- Feb 2009 Total 1668 FNA

• Solid Nodules (788)
• Benign 630
• Malignant 158
• NonSolid (880)
• Benign 854
• Malignant 26

Solid NonSolid
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Take home points

• Relevant
• Solidity of the nodule
• Border characteristics
• Punctate calcifications

• Irrelevant
• Size
• Color Doppler features

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What is solidity?
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Darci T. Butcher, Tamara Alliston Valerie M.
Weaver Nature Reviews Cancer 9, 108-122 (February
2009)
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• Example Two nodules BOTH with solid US features
• Nodule 1 Soft and not stiff
• Nodule 2 Hard and stiff

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Ultrasound Elastography The New Sonic Boom
ShearWave Elastography
Supersonic Imagine US System
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The End