Basic Ultrasound Scan Techniques
The simulator offers three different scenarios that test your ability to perform the basic techniques required to perform general ultrasound scanning.
The video guides you through a step-by-step demonstration of the basic techniques required to begin general ultrasound scanning.
The anatomy provides 3D, 360-degree rotating images to illustrate the key structures and components comprising the abdomen and associated vessels.
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Step 1: Overview
The initial observation of an ultrasound scan or when picking up a transducer for the first time.
1.1.1. Anatomical directions
These terms are used both to describe the direction of movement of the transducer and to describe the relationship between various organs or structures.
|Superior (cephalad, cranial)||
Towards the patient's head
Towards the patient's feet
Towards the front of the patient
Towards the back of the patient
Patient's right side
Patient's left side
Towards the patient's midline
To the right or left of the patient's midline
1.1.2. Planes or body sections
There are four main scanning planes: sagittal, transverse, coronal, and oblique.
Sagittal or longitudinal
A lengthwise plane that divides a structure into left and right sides (often in the midline)
A horizontal plane that divides a structure into superior and inferior parts
A lengthwise plane that divides a structure into anterior and posterior portions
A plane that divides a structure at any angle which is not in the longitudinal, transverse, or coronal plane
Scan planes can apply to either the whole body or an individual organ.
1.1.3. On-screen orientation
To assist with orientation, most transducers have a notch or mark on the transducer that corresponds to a mark on the screen.
Images are displayed on the ultrasound screen in a standardized way. Imagine standing at the foot of a bed and looking up at a large loaf of sliced bread. The captured image is projected as a slice, lifted onto the screen.
A transverse image is orientated with the patient's right side to the left of the screen. Sagittal images are displayed with the patient's head to the left of the screen.
1.1.4. Abdominal quadrants and regions
The abdomen can be divided into four quadrants and nine regions.
The four areas of the abdomen can be defined by two imaginary lines (one longitudinal and one transverse) intersecting at the umbilicus. The four quadrants are: right upper quadrant (RUQ), right lower quadrant (RLQ), left upper quadrant (LUQ), and left lower quadrant (LLQ).
Two horizontal and two vertical lines define nine regions: right hypochondrium, epigastrium, left hypochondrium, right lumbar, umbilical, left lumbar, right iliac fossa, hypogastrium, and left iliac fossa. Within the nine regions the following abdominal organs can be identified:
1.2. Cross sectional anatomy
All the structures in the upper abdomen are related to each other in three dimensions.
1.3. Abdominal vascular landmarks
Step 2: Preprocedure considerations
2.1. Patient preparation
Introduce yourself to the patient. Ensure the patient is wearing appropriate clothing for the examination.
Check the patient's details and confirm the area to be examined. Briefly explain the procedure to the patient, the length of time the scan will take, and obtain verbal consent.
Take a brief patient history. Ask about current medication and about latex or gel allergy. Ask about recent or previous imaging (particularly imaging relevant to the current problem). Information provided by the patient will often assist the sonographer to modify or add to the examination protocol. Many institutions provide a history questionnaire for the sonographer or the patient to fill in. The history questionnaire is specific to the requirements of each department.
2.3. Patient position
There are six patient positions commonly used for abdominal imaging. These positions are reasonably comfortable for the patient and provide improved access for efficient image capture.
- Dorsal recumbent position
- Lie on back
- Head and shoulders slightly elevated
- Pillow under knees
- Arms at side or over head
- Also called lateral decubitus
- Lie on the right or left side
- Arms in front
- Dependent arm over head
- Dependent leg straight
- Lateral oblique
- From the lateral position the patient rolls back to angle of 30 to 40 degrees
- Support with pillows or wedges
- Can be right or left posterior oblique (RPO or LPO)
- Lie on abdomen
- Arms flexed at side
- Pillow under chest to relieve pressure
- Feet extended off table
- Sitting upright
- Sitting up, supporting upper body with extended arms
- Legs over side of table
- Modified Fowler
- Elevation of head and shoulders
- Elevation of upper portion of back
- Knees elevated
- Improves blood flow to the inferior vena cava
- Lie on back
- Head of bed tilted 30 to 40 degrees toward floor
- Used to elevate pelvis higher than the head
- Reverse Trendelenburg
- Lie on back
- Head of bed raised 30 to 40 degrees
- Feet supported on a footrest
- Used for lower extremity vascular scans
Step 3: Procedure
Scan technique is a combination of hand-eye coordination, three dimensional visualization, and a lot of practice.
3.1. Image optimization
Although modern ultrasound machines provide preset specifications for many scanning protocols, they may not result in a perfect image for every patient. The image can be optimized by checking a number of parameters and adjusting them for each patient:
When starting an examination, you first need to select an appropriate transducer to get the best achievable resolution (this is determined by the amount of attenuation). There is a variety of arrays and frequencies available.
"Array" refers to the way the crystal elements of the transducer are aligned during manufacture. The number of elements, their size, shape, and arrangement varies considerably for different transducers and from manufacturer to manufacturer.
Transducers are available in the following arrays: linear, curved linear (curvilinear), and phased (or sector) array.
Either single frequency transducers or, if available, multifrequency transducers (typically in the range of 2-12 MHz) are used. As a general guideline the higher frequency transducers (with shorter wavelength) provide more detail but less penetration. A lower frequency transducer (with longer wavelength) will be suitable for larger patients and deeper structures, with increased penetration but less detail. Optimal images are produced when the highest frequency transducer that allows sufficient penetration is selected.
For slim patients, children, and to view superficial structures the best images are obtained by using higher frequency transducers.
Field of view (FOV)
The field of view (FOV) determines the size of the area of tissue shown. The smaller the FOV, the better the resolution. A small FOV allows higher frame rates and increased line density (produces a clearer picture).
The best lateral resolution is achieved where the focal zones pass through the organ. The focal zone(s) should always be placed at the depth of major interest.
Time gain compensation (TGC)
Almost all systems now use segmented controls, each one operating over a short range. Time gain compensation (TGC) counters the effect of attenuation and is used to keep the image uniformly bright throughout the full depth of the display.
Zoom is available both as write and as read zoom. Write zoom improves spatial resolution at the expense of field of view. Read zoom magnifies part of the existing image and does not affect image resolution.
The gain sets the overall level of amplification of all echo signals. Gain affects the brightness of the echoes in the display.
Dynamic range refers to the range of echoes, from strongest to weakest, that can be shown on the display at any one time. As dynamic range is reduced, low-level echoes are removed from the display, increasing the amount of contrast.
3.2. Transducer manipulation
There are four standard transducer manipulations. They are used in combination, together with correct transducer pressure, to acquire appropriate images.
Moving the transducer from one area to another region or area.
Angling the transducer from side to side in a sagittal scan plane, or from superior to inferior (or vice versa) on a transverse scan plane (without sliding).
Angling superior to inferior (or vice versa) on a sagittal scan plane or right and left (or vice versa) on a transverse scan plane so that one end of the transducer loses contact with the skin.
Turning the transducer from one scan plane to another plane.
Most student sonographers are timid when it comes to applying pressure on the abdomen with the transducer. Image quality will often improve with firmer transducer pressure for a number of reasons:
- Sound transmission will be more efficient as air is completely eliminated from the skin-to-transducer interface
- The organ being imaged will be closer to the transducer, thus reducing attenuation
- Bowel (or bowel gas) may be displaced, especially when visualizing deeper structures like the aorta
There are three approaches for the imaging of the upper abdomen:
Not all the organs and structures in the upper abdomen can be visualized from one approach. What might work for one patient may not for another.
Patient habitus can influence the choice of approach. For example, when scanning the kidneys of a slim young patient, a perpendicular approach may provide excellent images. An elderly patient with some degenerative changes to the spine may require a subcostal approach. Some larger patients will benefit from an intercostal approach.
All the upper abdominal organs lie close to the diaphragm. The diaphragm moves the abdominal contents (including bowel gas and ribs) past the transducer with each breath. Making use of the patient's breathing, instructing the patient to perform arrested inspiration (breathing in) or arrested expiration (breathing out), can often significantly improve the image quality.
An acoustic window is an area or structure through which ultrasound waves move freely. There are three main acoustic windows used in abdominal ultrasound: liver, spleen, and stomach.
The liver acts as an excellent window when imaging the upper abdomen, especially from the subcostal or intercostal approach.
The spleen can be used as a window to visualize the left kidney or tail of the pancreas.
When obtaining images of the body and tail of the pancreas, it may be useful to utilize a fluid-filled stomach as a window after asking the patient to drink some water.
3.6. Survey scan
A survey is performed at the start of every scan. The survey involves a series of real-time sliding movements in sagittal and transverse of the whole abdomen. There are a number of reasons to perform a survey scan:
- To ensure the correct transducer and preset have been selected
- To ensure the parameters have been correctly adjusted, including depth, focus, and time gain compensation (TGC)
- To obtain an overview of any unusual features or pathology and to allow the examination protocol to be amended accordingly
Every department or institution will have a set of protocols for each type of examination and region of interest. Protocols are used for a number of reasons:
- To allow standardization of each examination for quality assurance purposes
- As a methodical technique to ensure that every region and structure is studied fully
- To ensure that any obscure or secondary pathology is identified
A set of guidelines for the annotation of all ultrasound images may be included in a department protocol. Most ultrasound machines give the option to save a list of common annotations that can be activated with a single function.
It is very important that all images are correctly annotated. The following should be included in an annotation protocol.
- Orientation - careful use of the mark on the transducer and the corresponding mark on the screen will assist the sonographer to adhere to the agreed orientation protocol. Remember in a sagittal view, the patient's head will be to the left of the screen and in a transverse view, the patient's right will be to the left of the screen as though a slice has been lifted up and viewed from the foot of the bed
- Right or left - a protocol may state the department preference for R, L, RT, LT, or full spelling of right and left
- Scan plane - includes longitudinal (or sagittal), transverse, oblique, or coronal. A protocol will advise what abbreviations can be used. It is also necessary to decide whether scan plane refers to body scan planes or organ scan planes. For example, a longitudinal view of the pancreas would be obtained in a transverse scan plane
- Body marker - most ultrasound machines give the option of using a body marker. This feature enables the sonographer to locate the transducer position and orientation in a simple line drawing which appears on the screen. The use of a body marker is the easiest way to avoid potential confusion between a body or organ scan plane
- Structure scanned - a protocol will include a list of all structures to be imaged and may also advise the acceptable abbreviations. For example, right kidney may be RK, gallbladder may be GB, and inferior vena cava abbreviated to IVC
- Patient position - common positions (supine, erect, decubitus, posterior oblique) may be identified in the protocol together with abbreviations (left lateral decubitus may be LLD, right posterior oblique may be RPO)
- Pathology - it is important to identify pathology and any unusual or abnormal features. The protocol may advise on the use of arrows, cursors and on-screen terms
Together with the required views and annotation protocols, there is usually advice on a standard way to measure various structures. Certain measurements will be mandatory, for example the length of a kidney, the diameter of the aorta, or the diameter of the bile duct.
- Measurement principles
- Utilize depth, zoom, and focus to ensure the structure to be measured is in the middle of the screen, almost filling the field of view with the focal zones at the level of the measurement
- Use sweeping and rocking movements to align the measurement plane to be parallel or perpendicular to the central axis of the transducer
- Use small movements in real time to clearly identify the outer margins of the structure
- Revise the department protocol to identify the mandatory measurements and the placement of the measuring cursor, including, eg, the cursor placement on the inner or outer wall of tubular structures
The following examples may appear in a department protocol, enabling sonographers to be confident that there is a consistent and reliable standard in each department:
- Renal measurements (see reference)
- Kidney length is measured along a long axis of the kidney, which is an oblique plane extending from the medial upper pole to the more lateral and anterior lower pole
- Upper and lower poles must be carefully identified
- Measurement is most accurate in a coronal or sagittal view with the patient supine or decubitus
- To calculate a volume three perpendicular measurements are made
- Measurement of the abdominal aorta (see reference)
- Longitudinal views of the aorta from outer to outer edge at largest diameter
- Transverse view is orientated to compensate for vessel angulation
- The outer to outer AP diameter and width is recorded and the larger diameter used
- Transverse AP measurements are less variable than width measurements because axial resolution is better than lateral resolution
Step 4: Postprocedure considerations
Before ending the examination, particularly when pathology or atypical anatomy has been found, it may be useful to have the reading physician come into the room and re-scan the areas of interest or concern. This allows the reading physician to clarify the pathology or atypical anatomy for reporting purposes.
Give the patient a towel or cloth to wipe off the gel.
Allow the patient to sit up. Explain to the patient that the images will be reported by the reading physician. A report will go to the referring physician (and/or their family physician) in a few days. The result will be given to them by their referring physician.
Take the patient to the changing room, or allow them some privacy, to get dressed.
Remove your gloves.
Wipe clean the ultrasound transducers, and place them back into the slots on the machine. Replace the gel in the warmer.
End the study on the ultrasound machine (this sends the images to a PACS system or printer) or delete the patient identification (ID) from the ultrasound machine.
Change the linen and tidy the room.
4.2. Preliminary report
Write up a sonographer's preliminary report on the worksheet. A preliminary report includes:
- Location of scan plane
- Normal or abnormal echogenicity
- Measurements and locations
- Presence of shadowing or enhancement
- Presence and location of masses
- Presence and location of fluid collections
- Any technical difficulties
Step 5: Professional considerations
As with many repetitive jobs, there is a danger of injury because of repeated actions.
Injury in the workplace
The most common injuries are tendonitis and tenosynovitis involving the shoulder, neck, wrist, and back. Injuries are often related to prolonged arm abduction, muscle loading, and constant transducer pressure.
A number of factors may be involved:
- Poorly designed equipment
- Improper body mechanics
- Length of time a procedure takes
- Inappropriate force
- Insufficient breaks
Prevention of workplace injury
More than one factor, related to ergonomics of the equipment and to the sonographer's actions, is involved in prevention.
- Position the patient as close to the sonographer as possible
- Use an adjustable examination table and sonographer's chair
- The sonographer's scanning arm should be held as close to their body as possible
- If available, use an arm support with the scanning arm
- Rest the opposite arm in your lap
- When sitting, support your feet on a foot stool
- Avoid excessive reaching, bending, or twisting
- Position the monitor directly in front of the sonographer's chair
- Be aware of wellness programs and education resources
5.2. Professional involvement
Memberships in professional organizations are valuable because they are inexpensive for students and an investment for the future.
Membership benefits include:
- Continuing education
- Access to professional information
- Participation in leadership roles
- Professional development
- Advocating for state and federal regulatory issues
- Assisting career advancement
- Remaining current with the latest research
- Opportunity for publication
- Access to financial, insurance, and health programs
Links to websites:
Online CME courses. GE healthcare website. Available at http://www.gehealthcare.com/usen/ultrasound/msucme.html. Accessed May 14, 2009.
Craig, M. Essentials of Sonography and Patient Care. 2nd ed. St. Louis, MI: Saunders Elsevier; 2006.
Edelman, SK. Understanding Ultrasound Physics. 3rd ed. Woodlands, Tx: ESP; 2007.
Gent, R. Applied Physics and Technology of Diagnostic Ultrasound. Adelaide, SA: Milner; 1997.
Goldberg, BB, McGahan, JP. Atlas of Ultrasound Measurements. 2nd ed. Philadelphia, PA: Mosby Elsevier; 2006.
Hagen-Ansert, SL. Textbook of Diagnostic Ultrasonography. 6th ed. St. Louis, MI: Mosby Elsevier; 2006.
Hofer, M. The Ultrasound Teaching Manual. 2nd ed. New York, NY: Thieme; 2005.
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