intro to ultrasounds

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Questions and Answers

What happens when an ultrasound beam encounters a highly reflective interface?

It results in a slice thickness effect impacting image clarity.

It reflects back completely and creates a distal shadow. (correct)

It leads to the formation of an echo that enhances image brightness.

It creates a bright area deep to a fluid structure.

Which term describes a structure that appears as a darker shade of grey on an ultrasound image?

Hyperechoic

Hypoechoic (correct)

Isoechoic

Anechoic

Which of the following best describes 'slice thickness' in ultrasound imaging?

The ability of a structure to absorb sound waves effectively.

The separation between multiple structures in an image.

The width of the ultrasound beam that impacts image resolution. (correct)

The depth increment at which images are obtained.

What does 'acoustic shadowing' refer to in ultrasound imaging?

The complete reflection and shadowing distal to a reflective interface. Signup and view all the answers

Which echogenicity term refers to a structure that appears entirely black on an ultrasound image?

Anechoic Signup and view all the answers

What causes the piezo-elements in the transducer to produce an ultrasound wave?

A steady current that causes oscillation Signup and view all the answers

Which of the following best describes the term 'refraction' in ultrasonography?

The alteration in wave direction due to tissue density changes Signup and view all the answers

What is one of the advantages of using abdominal ultrasound over radiography?

Ability to visualize soft tissues in real-time Signup and view all the answers

Which imaging fault is most likely to occur due to improper positioning during an ultrasound?

Reduced tissue contrast Signup and view all the answers

What is the result when sound waves are received at the transducer?

They cause compression of the crystals Signup and view all the answers

What is the purpose of a Thoracic Focused Assessment with Sonography for Trauma (TFAST)?

To examine for pleural space disease and pericardial effusions Signup and view all the answers

Which of the following describes the characteristic ultrasound sign indicating the presence of fluid?

Hypoechoic effusion Signup and view all the answers

In the Vet BLUE assessment, which lung lobe region is NOT evaluated?

Basal lung lobe region Signup and view all the answers

What does the absence of the 'glide sign' indicate in a thoracic ultrasound?

Presence of air in the pleural space Signup and view all the answers

Which ultrasound artefact is associated with the rib in thoracic ultrasound imaging?

Hyperechoic line with distal acoustic shadow Signup and view all the answers

What is the main consequence of attenuation in ultrasound?

Loss of energy of the wave Signup and view all the answers

Which ultrasound probe type features a fan-shaped image?

Curved Array Signup and view all the answers

What determines the axial resolution in ultrasound?

Path of the beam Signup and view all the answers

What effect does a high gain setting have on an ultrasound image?

Increases overall brightness Signup and view all the answers

What is the role of Time Gain Compensation (TGC) in ultrasound imaging?

Balances brightness at different tissue depths Signup and view all the answers

Which statement is true regarding lateral resolution?

Is determined by beam width Signup and view all the answers

What causes mirror image artifacts in ultrasound imaging?

Curved reflective surfaces Signup and view all the answers

Which of the following describes a characteristic of high frequency ultrasound?

Good axial resolution Signup and view all the answers

What characterizes a homogeneous echotexture?

Uniform distribution of grey shade or dot size Signup and view all the answers

Which of the following is NOT one of the roentgen signs for describing a lesion?

Color Signup and view all the answers

What is a primary advantage of abdominal ultrasound?

Non-invasive and safe Signup and view all the answers

What is the purpose of performing a POCUS scan in an emergency situation?

To identify free fluid often following trauma Signup and view all the answers

Which echocardiography view is taken from the left side of the chest?

Left apical 4 and 5 chamber view Signup and view all the answers

Which factor can interfere with sound transmission during an abdominal ultrasound?

Gas in the gastrointestinal tract Signup and view all the answers

What is the recommended positioning of the patient for abdominal ultrasound?

Lateral recumbency Signup and view all the answers

What preparation is recommended for a patient prior to undergoing an abdominal ultrasound?

Withholding food for 8 hours Signup and view all the answers

Which of the following is a disadvantage of abdominal ultrasound?

Limited in visualizing diffuse disease Signup and view all the answers

What is the purpose of using ultrasound guidance for procedures such as abdominocentesis?

To improve target acquisition Signup and view all the answers

Which of the following is NOT a required step in patient preparation for echocardiography?

Patient should lie in dorsal recumbency Signup and view all the answers

Which of the following statements about echocardiography is correct?

It can reveal abnormalities based on standard views Signup and view all the answers

Which measurement is NOT typically assessed during an abdominal ultrasound?

Depth of anesthesia Signup and view all the answers

Study Notes

Basic Ultrasonography

Ultrasonography is a medical imaging technique using sound waves to create images of internal structures.
The technique involves transmitting sound waves through the body and interpreting returning echoes to form an image.
Learning outcomes include understanding the generation and delivery of ultrasound, and the differences between probes.
Learning goals further include describing ultrasonographic images, recognizing potential image faults, and discussing the advantages and disadvantages of abdominal ultrasound compared to radiography.

Basic Ultrasound Principles

Ultrasound uses sound waves to create images of tissues.
An electrical current is applied to crystals in a transducer, causing them to vibrate, producing sound waves.
Returning sound waves create an electrical signal that is interpreted to form an image.

Interaction with Tissues

Reflection: Sound waves bounce back from tissues, creating echoes.
Refraction: Sound waves change direction when passing through tissues with different densities.
Diffraction: Sound waves bend or spread as they pass through structures or around corners.
Attenuation: Sound waves lose energy as they travel through tissues due to scattering and absorption.

Ultrasound Probes

Linear Array: Crystals in a line, creating rectangular images.
Curved Array: Crystals in a curve, producing fan-shaped images, allowing for greater depth view.
Phased Array: Crystals in a line, electronically steered to produce fan-shaped images with greater depth, offering good lateral resolution.

Frequency

High frequency: Better axial resolution but poorer penetration.
Low frequency: Poorer axial resolution but better penetration.

Basics of an Ultrasound Image: Echogenicity, Echotexture

Different tissues appear as different shades of gray on ultrasound images. This is termed "echogenicity," and it is based on how tissues reflect ultrasound waves.
The overall pattern of gray shades in an image is referred to as "echotexture", providing insight into the uniformity or heterogeneity of a tissue.
Structures displaying a similar shade to surrounding tissues are considered "isoechoic"; those showing a darker shade, "hypoechoic," and those showing a lighter shade, "hyperechoic". Completely black regions are considered "anechoic."

Image Descriptors: Describing a Lesion

A homogeneous area displays a consistent echotexture.
A heterogeneous area shows an inconsistent echotexture.
Key factors to describe a lesion include its location, echotexture, measurements, outline, number, size, margins and any potential artifacts.

Ultrasound Artifacts

Reverberation: Parallel bright lines caused by multiple reflections between structures.
Mirror Image: A duplicated image of a structure due to reflection from a curved boundary.
Acoustic Enhancement: A brighter area behind a fluid-filled or gas-filled structure due to increased transmission of ultrasound waves.
Poor Probe Contact: A weak image or distorted artifacts result from inadequate coupling between the ultrasound probe and the patient's skin. (not properly applying gel to the area)
Acoustic Shadowing: A dark area behind a highly reflective structure that blocks sound transmission.
Edge Shadowing: Shadowing on the edge of a structure likely due to differences in tissue densities.
Slice Thickness: Image distortion due to the width of the ultrasound beam.

Abdominal Ultrasound

Elective indications: Conditions affecting abdominal organs, tumor identification, staging of diseases, biopsies.
Emergency indications: Free fluid identification after trauma.
Scanning planes: DH, HR, SR, CC are used for specific views.
Advantages: Non-invasive, excellent morphological information, real-time sampling.
Disadvantages: Limited functional information, problematic with diffuse disease, potential for artifacts, need for sedation or clipping.
Patient Preparation: Fasting, clipping, applying gel, patient positioning.

Ultrasound-Guided Techniques

Ultrasound guidance improves accuracy during procedures like abdominocentesis, cystocentesis and biopsies.

Echocardiography

Indications: Heart murmurs, ECG abnormalities, radiographic abnormalities, hypertension, dyspnea, syncope, arterial thromboembolism and pre-breeding assessments.
Preparation: Clip around the chest area. Position patient in lateral recumbency with appropriate cut-out of the table.
Views: Right parasternal long axis, right parasternal short axis, subcostal, left apical 4 and 5 chamber. Essential for evaluating heart structure and function.

Thoracic Ultrasound

Indications: Assessing pleural space disease and pericardial effusions using the TFAST scan protocol.
Includes various point scans for examination.

Vet BLUE Assessment

Used to evaluate pulmonary parenchyma in four areas of the thorax.

Summary:

Key concepts of ultrasonography, its principles and applications are presented in this study material.
Practical preparation steps, benefits, and drawbacks are included for each area covered.

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