Sonography Lecture Notes

Ultrasound Scanning Principles and Practices

Introduction to Ultrasound

• Ultrasound is a wave with a frequency exceeding the upper limit of human hearing.

  • Frequency > 20,000 Hz (20 kHz).

• Audible sound:

  • Frequency: 20 - 20,000 Hz.

• Process:

  • Transducer emits sound waves.

  • Waves bounce off structures and return as echoes.

  • Transducer interprets echoes and creates gray dots on the screen.

  • Millions of echoes per second create a real-time image.

Professional Standards

• Dress appropriately in training facilities and labs.

• Introduce yourself to the patient. Practice this, even if you know the person.

  • "Hi, my name is…"

• Refer to patients by their appropriate name, not first names or terms like "honey" or "sweetie."

• Explain the procedure to the patient to make them feel comfortable.

Patient Interaction

• Introduce yourself.

  • "I'm Nancy, your sonographer. This is what we're doing today."

• In the lab, practice introductions.

  • "Hi, so and so. What's your name? What's your date of birth?"

• Verify patient information (name, date of birth) before bringing them into the room.

• Briefly explain the exam.

  • "I am going to take images of the organs of your abdomen. I'm gonna use some gel to do that. The gel might be a little bit cold. I'm gonna ask you to take a deep breath in and hold it throughout the exam. If I forget to ask you to breathe, just go ahead and breathe, and I'll ask you again to take a deep breath and then hold it."

• Inform the patient about potential pressure during the exam.

  • "I'm going to be pressing. You may feel a little pressure. You feel pain. Let me know."

• Obtain medical history to understand the reason for the scan.

  • Example: "I'm having pain." "Where are you having pain?" "How long have you had the pain?" "When did the pain start?" "Does the pain start when you eat?"

• Ensure patient comfort to facilitate information sharing.

Uniforms and Appearance

• Inappropriate uniforms:

  • Too tight.

  • Too short.

  • Too revealing.

• Uniform policy: Students must wear appropriate uniforms.

• Appropriate uniforms:

  • Not super baggy, not super tight.

  • Cover past the hips.

  • Maroon or wine-colored.

Image Documentation

• Machine settings automatically document:

  • Patient's name and medical ID number.

  • Sonographer's name or initials.

  • Date and time of the exam.

  • Scanning site (e.g., Lakewood Regional Medical Center).

  • Transducer information.

  • Area of interest (annotated on screen).

  • Patient position (supine, decubitus, etc.).

  • Scanning plane (long sagittal, transverse, coronal).

• Film annotations should be confined to the margins around the image, not on the anatomy itself.

• Use up-to-date calibrated ultrasound machines.

• Areas of interest should be represented in at least two scanning planes.

• Take representative images to show the radiologist the findings.

Operator Dependence of Ultrasound

• Ultrasound is operator-dependent.

• If the sonographer doesn't see it and represent it, it won't be seen in the images.

• Image quality and representation of findings depend on the operator.

Ergonomics and Scanning Techniques

• Sonographers can sit or stand while scanning.

• Adjust the bed to the appropriate height (hip level).

• Use the right hand to hold the transducer and the left hand on the machine.

• Maintain the left hand on the machine at all times.

• Hold the transducer, not the cord.

• Avoid wrapping the cord around arms or neck.

• Wear a glove on the scanning (right) hand; no glove on the left hand.

• Ergonomics: Arrange the workspace to be comfortable and productive, reducing physical stress.

Correct Posture and Positioning

• Adjust the machine, console, and monitor for comfortable positioning.

• Screen at eye level.

• Elbow at 90 degrees, close to the body.

• Avoid a "death grip" on the transducer.

  • A tighter grip increases tension on the hand and wrist.

  • Hold the transducer loosely but with control.

  • Relax.

• Arm posture contributes to shoulder and neck pain.

• Keep a straight neck, avoid twisting and bending.

• Ideal standing position:

  • Monitor at arm's length, top at or just below eye level.

  • Upper arms close to the body, elbow at approximately 90 degrees.

  • Keyboard and mouse on the same surface.

  • Wrists straight, hands at or below the elbow.

  • Head, neck, torso, and legs in line.

Transducer Cleaning

• Clean transducers between patients to avoid transmitting infectious material.

• Wipe off the transducer after each exam.

• Clean with a suitable effective agent each day.

• Use wipes specifically designed for transducers (soda wipes), not harsh chemicals like Clorox wipes.

• Avoid touching the tip of the gel bottle to the transducer or patient's skin to prevent contamination.

• Apply gel directly to the patient's skin without touching the bottle to the skin.

Patient Positions

• Supine: Lying on the back.

• Prone: Lying on the front or abdomen (not used in this class).

• Sitting: Erect or semi-erect (Bowler's or semi-Bowler's position).

• Right Lateral Decubitus: Lying on the right side.

• Left Lateral Decubitus: Lying on the left side.

• Right Posterior Oblique: Lying on the back with the left side elevated about 45 degrees.

• Left Posterior Oblique: Lying on the back with the right side elevated about 45 degrees.

Scanning Planes

• Establish the direction the ultrasound beam enters the patient's body.

• Anatomic planes are two-dimensional.

• Interpretation depends on the transducer location and sound wave approach.

• Sagittal: Divides the body into equal right and left sections. If the plane is moved from that midline, it is known as a parasagittal right and left sections.

• Coronal: Divides the body into anterior and posterior sections.

• Transverse: Divides the body into unequal superior and inferior sections.

• Longitudinal views show a structure's length and depth (long axis). Longitudinal and sagittal are used interchangeably.

• Transverse (axial) view shows the structure's width and depth (cross-section).

Monitor Orientation

• Understanding the orientation of the image on the monitor is crucial.

• Longitudinal Plane (Anterior Approach):

  • Top: Anterior.

  • Bottom: Posterior.

  • Left: Superior (head).

  • Right: Inferior (feet).

• Transverse Plane (Anterior Approach):

  • Top: Anterior.

  • Bottom: Posterior.

  • Left: Patient's Right.

  • Right: Patient's Left.

• Coronal Plane (Right Lateral Approach):

  • Top: Right Lateral.

  • Bottom: Medial.

  • Sides: Superior and Inferior.

• Transverse Plane (Right Lateral Approach):

  • Top: Right Lateral.

  • Bottom: Medial.

  • Left: Posterior.

  • Right: Anterior.

• Coronal Plane (Left Lateral Approach):

  • Top: Left Lateral.

  • Bottom: Medial.

  • Sides: Superior and Inferior.

• Transverse Plane (Left Lateral Approach):

  • Top: Left Lateral.

  • Bottom: Medial.

  • Left: Anterior.

  • Right: Posterior.

Transducers

• Various types exist, but only one will be used in this class.

• Parts of a transducer:

  • Footprint: Part that touches the patient (curved, flat, wide, or thin).

  • Body or Housing: Contains wires and internal components.

  • Cable: Connects the transducer to the machine.

• Frequencies: Higher frequency for superficial structures, lower frequency for deeper structures.

• Holding the Transducer:

  • Light but firm grip.

  • Crystals are inside of those transducers that produce our images. So you don't want it falling.

  • Hold it like a pencil at the base of the transducer to have good control of that transducer.

  • Hold it closer to that cord or somewhere along the middle to have a good grip on that transducer

  • Avoid straightening the wrist.

Transducer Manipulation

• Small movements make big changes.

• Watch the screen while scanning to correlate hand movements with the image.

• Transducer Indicator/Orientation Marker (Notch):

  • Should face up towards the patient's head or to the right towards you.

  • Turning the notch down towards the patient's feet, now you're upside down.

• Maintain contact with the patient to see the image.

• Don't use excessive pressure, except with "fluffy" patients to image through fat tissue.

• Air and bone are enemies.

Machine Controls

• Each machine has an indicator matching the manufacturer (e.g., P for Philips).

Image Optimization and Machine Settings

• Make sure that you're scanning you're not you're not starting upside down or backwards. So that orientation marker or notch should either be facing up or facing towards you. Never this way, never down. Because then you're gonna be backwards or upside down.

• Hold the transducer close to the base with a good grip, not by the cord.

• Statements regarding how to hold the transducer is incorrect? B. Hold the transducer at the footprint.

• Manipulating: We slide our transducer sometimes up and down, left to right. We tilt our transducer, what we call fanning. We rotate. We rock the transducer, which is something we call heel toe. Another technique that could be considered a fifth movement would be compression, pressing down on that on that patient.

• The transducer that is used in this class has a curve to its footprint, and that curve that it has gives a wider field of view.
  *Every machine is gonna have a little slot where they go. So that's where you always wanna put it. Even if you're just going to get whatever you printed or type something, put it on that little holder. And that is to ensure that they don't fall, that they don't break. It it secures them in place.

• Always use scanning gel because what try putting your transducer down and looking at what image you get when you don't use gel. It's gonna be black. You're not gonna see anything. Gel allows us to visualize the organs in the body.

• We intercostal, we may be scanning between the ribs. We may have to rotate ankle, have our transducer projagigula. Sometimes we have to toggle our transducer. We have the heel toe where we're moving it towards the head, towards the body. It depends on what we're trying to image. You wanna scan according to the lie of the organ.

• Monitor Orientation.

The Machine in Use

• What is the patient position? Left lateral decubitus.

• What is the scanning plane? Paroma.

• Briefly about the machine the transducer that we use converts electrical energy into acoustic energy during transmission at the time it's sending out the signal, and then turns and then when that signal come comes back, it turns in that acoustic energy into electric energy.

• The display is what we're seeing our image on.

• TGC.

• Compensate making all the echoes arising from similar structures appear the same brightness regardless of how to they have to travel. That is something that we adjust. We're gonna show you how to adjust that.

• TGC looks like these toggles. There's usually a few of them, and they correlate, and they can be adjusted individually.

• This is the same patient. Same image. Really bright up here. A little bit brighter down here. so adjusted the TTC so that the image appears uniform. Appears mid-level gray throughout the entire image And so that's what these toggles are being used for. We adjust them.

  • Adjust overall amplification, which is the strength of returned that are displayed on the screen. Like the brightness adjusted on television. You turn the whole thing bright or the whole thing dark. It does not take account the different depths of the returning sound wave like the TGC did, so it doesn't care what depth it came from. You're telling the machine. I want the whole thing to look brighter or the whole thing to look darker.

• This one being is an example of adjusting the depth to make the whole thing brighter, and this one, adjusting the depth to make the whole thing darker.

• It does not take account the different depths of the returning sound wave, like the TGC did. So it doesn't care what depth it came from. You're telling the machine. I want the whole thing to look brighter or the whole thing to look darker.

• Focus is the same shape coming out we make at the best imagine we put it.
  *So resolution means image quality.

• Students are gonna show you that button as well. How to take an image, or how to save an image, or how do we print an image? So there's a knob that's called the freeze button, and it's like when you take your picture on a camera. Right? You're gonna focus. You're gonna change the depth. You're gonna change everything, and then you're gonna freeze it. When you're freezing, your image is gonna freeze and that's the image that you can print. And images should be frozen before they get printed.

Depth

Each of these represents one centimeter in-depth. That's one centimeter deep, two centimeters, three, five, six, seven. I'm telling the machine, I only wanna see anatomy up to seven centimeters. But we can change our depth. We can we can increase the depth and say, I want to add three more centimeters, and now I wanna see anatomy down to that 10 centimeter mark. Or we can decrease our depth and say, I only wanna see anatomy four centimeters deep. So maybe we're gonna cut off that kidney. So we're just telling the machine, I only want you to display echos from up to four centimeters, or I want you to display echos up to 15 centimeters. So it's adjustable.

Scanning Protocol

Abnormalities Identified

Size measurements must be taken in at least two planes when we see some when we see an abnormality or when we want to measure an organ.

Compositional

Is there something solid or Cystic Is it complex? Is cystic? And it has some solid components. So that's the composition of whatever we're seeing.

Echo Texture

We'll say a term we will say it's homogeneous. That means it has an even echo pattern reflection that has a very uniform composition throughout it.

Texture

Those two terms we interchange very commonly, echogenic means can increase. Hypo means lowering. Echoic equals Same thing.

Shadow Artifacts

Some artifacts actually help us make a diagnosis, like it a patient gallstones gallstones cast enhancement is it and it's gonna that demonstrates a lot of brightness behind it. So tell them that they're saw a stick mixed and they're located.