DMST 202: Ultrasound Scanning Fundamentals - Great Vessels

Great Vessels Overview

Aorta & Inferior Vena Cava (IVC)

• Great vessels that lie midline along the long axis of the body in the sagittal plane.

• Anechoic tubes.

• The aorta lies to the left of the IVC.

Abdominal Aorta

Introduction

• Patient Preparation:

  • Fasting is recommended.

• Location:

  • Just left of midline.

  • Anterior to the vertebral column.

  • The proximal aorta courses more posteriorly, while the distal aorta courses more anteriorly.

  • Courses superior to inferior in the body.

• Key Branches:

  • Celiac Axis (CA)

  • Superior Mesenteric Artery (SMA)

Indications for an Aortic Sonogram

• Pulsatile abdominal mass.

• Abdominal pain.

• Known AAA (Abdominal Aortic Aneurysm).

• Family history of AAA.

Normal Measurements

• Anteroposterior measurement is < 3 cm, measured at the distal end of the aorta.

Normal Sonographic Appearance

• Tubular structure.

• Tapers from cranial to caudal end.

• Contains echogenic bright walls.

• The lumen appears anechoic (echo-free).

• Non-compressible.

• Pulsatile (cannot be compressed with pressure).

Detailed Sonographic Appearance

• Normal Aorta characteristics:

  • To the left of the IVC.

  • Echogenic bright walls.

  • Pulsatile.

  • Tapers distally.

  • Non-compressible.

  • Proximal portion courses posteriorly as it passes through the diaphragm.

  • Distal portion is more anterior.

Celiac Axis (CA)

• Branches off the proximal aorta anteriorly.

• The Superior Mesenteric Artery (SMA) branches after the CA, running inferiorly along the course of the aorta.

• Scanning Windows and Breathing Techniques:

  • Probe should be placed in the midline of the abdomen from xiphisternum (xiphoid process) to umbilicus.

  • Deep breath in and/or normal breathing for proximal aorta; normal breathing for distal aorta.

Inferior Vena Cava (IVC)

Introduction

• Patient Preparation:

  • Fasting is recommended.

• Location:

  • Just right of midline.

  • Sits anterior to the vertebral column (less visible due to being collapsible).

Scanning Windows and Breathing Techniques

• Probe placed in the midline of the abdomen from the xiphisternum to umbilicus.

• Deep breath in and/or normal breathing for proximal IVC; normal breathing for distal IVC.

Indications for an IVC Sonogram

• Abdominal pain.

• Heart disease.

Normal Sonographic Appearance

• Tubular structure.

• Contains thin, undulating walls.

• Lumen appears anechoic (echo-free).

• Compressible (wavy walls, not as bright as aorta, depicted by mobility with patient's breath).

Required Images

Aorta (Sagittal and Transverse Planes)

• Sagittal Plane:

  • SAG AO PROX

  • SAG AO DIST

• Transverse Plane:

  • TRX AO DIST

  • TRX AO BIF

IVC (Sagittal Plane)

• SAG IVC

Required Anatomy to Identify

• Heart

• Diaphragm

• Liver

• Celiac Axis

• Superior Mesenteric Artery

Scanning Protocol for Great Vessels

Professionalism

1. Introduce yourself as a SAIT student.

2. Confirm the patient's first and last name.

3. Confirm the patient's birthday.

4. Explain the examination to the patient

5. Ask for permission to begin the examination.

Ultrasound Machine Setup

• Enter patient ID including:

  • Student's first and last name.

  • Student's SAIT ID number.

  • Scanner's initials.

• Select the ABD SAIT Preset.

• Select the 5MHz curvilinear transducer.

TGC Setup

1. Place a small amount of gel just below the xiphoid process (xiphisternal window).

2. Place the probe in the sagittal plane in this window; have the patient take a deep breath in and hold it.

3. Angle the probe towards the patient's right side; a large segment of the liver will appear.

4. Adjust depth to ensure the entire liver is visible.

5. Place focus posterior to the liver and check TGC for echo penetration.

6. Adjust gains appropriately for vessels to appear echo-free.

7. Allow patient to breathe out.

Adjustments for Abdominal Aorta/IVC

• Move the transducer back to the xiphisternal window.

• Ask the patient to take a deep breath in and hold it.

• Adjust depth so that proximal aorta/IVC is centered on the screen.

• Allow patient to breathe out.

Scanning Techniques for Abdominal Structures

Sagittal Interrogations of the Abdominal Aorta

• Place the probe in the xiphisternal window in a sagittal plane.

• Ask the patient for deep breaths and hold.

• Identify heart and diaphragm on the left.

• Locate aorta and place focus posterior to it.

• Elongate the proximal/mid aorta using transducer manipulation (rotation).

• Slide transducer down the abdomen while maintaining the long length of the aorta on the screen.

• After halfway down, allow the patient to breathe.

• Continue to slide down until the aorta tapers.

• Adjust focus throughout.

• Note: depth adjustment is not mandatory in Scanning Fundamentals but is required in future courses.

Transverse Interrogations of the Aorta

• Place the probe in the xiphisternal window in a transverse plane.

• Ask patient to take a deep breath.

• Tilt transducer superiorly to find heart.

• Tilt probe inferiorly and slide down the aorta in one motion.

• Identify celiac trunk and SMA.

• Once identified, allow patient to breathe out.

• Follow aorta down to bifurcation, adjusting focus and depth as necessary.

Sagittal Interrogations of the IVC

• Implement similar procedure as the aorta but specific to the IVC (must be careful to not compress the IVC).

• Ensure to interrogate from the diaphragm to the right renal vein.