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Acute Care Musculoskeletal (AC MSK)

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CURRICULUM

Review the curriculum to achieve IP certification

Earn CME credits at the same time via the MOC program

POCUS basics / Bases d'ÉCHO

All CPoCUS-certified Independent Practitioners (CPoCUS IPs) must be able to use the following controls on their ultrasound system:

Power:

Provides power to ultrasound machine. Ideally, all systems should be kept in sleep mode if there is a long start up time (i.e. longer than 30 seconds) so that there is always immediate PoCUS capability in emergency situations.

Depth:

Magnifies the area of interest and centers it in the vertical plane. The default for beginners is to maximize the depth for most scans (see detailed text for recommended starting depths for each specific scan). This control should be continually adjusted while scanning.

Gain:

Modifies the brightness on the screen and is used to ensure that the area of interest is clear enough to interpret correctly and to compensate for differences in tissue density and reflectivity as well as ultrasound artifacts. Should be continually adjusted while scanning.

Frequency:

Modifies the frequency of sound waves emitted from the ultrasound probe. Most modern ultrasound
systems will have variable frequency probes and allow the operator to change the probe frequency to one
of three settings:

General mode for scanning most tissues (3.5 MHz for the curvilinear probe)
Resolution mode for scanning near-surface structures or low-density tissues (5 MHz for the curvilinear probe)
Penetration mode for scanning deeper structures or high-density tissues (2.5 MHz for the curvilinear probe)

M-mode:

Measures movement along a vertical line (from near field to far field) on the ultrasound screen and graphs this over time. May be used to measure fetal heart rate in first trimester scanning, to detect movement along the pleural line in pneumothorax scanning, and to help estimate fractional shortening in the sub-xiphoid cardiac scan. The use of this control is NOT required for CPoCUS CORE IP certification.

Exam presets:

Provides pre-determined optimal settings for specific scans. Used before starting a scan to optimize the ultrasound system for a specific type of scan, such as abdominal, cardiac, or lung. Although the use of appropriate exam presets will enhance the ultrasound images produced, use of this control is NOT required for CPoCUS certification.

Freeze:

Freezes the image on the screen to allow the operator to identify essential anatomy and perform other functions such as measurements.

Focus:

Optimizes lateral resolution by ‘bending’ the ultrasound beams closer to one another and thus increasing their ability to distinguish whether what appears to be a single object is really two objects side by side at the same depth. Focus is usually represented by a marker on the side of the screen (often a triangle) that can be moved either towards the near field or the far field. Some machines will automatically set the focus at the mid-point of the screen, emphasizing that one should always center the area of interest at the mid-point of the screen with the depth function. Placing the focus at the level of the area of interest should be standard practice to optimize lateral resolution.

Calipers:

Produces electronic markers (i.e. calipers) when the image is frozen. These can be placed in two locations on the screen to output the true body distance between the markers. Can be used to measure the diameter of the abdominal aorta, the length of the fetal pole, the width of the myometrial mantle and the size of other structures.

Cineloop:

Allows one to review several seconds of a scan, going back in time from the moment the freeze button was pushed. Most systems use a trackpad or trackball to scroll back and forth through images. This function is helpful to review essential anatomy and physiology, especially during very dynamic scans and with moving tissues (e.g. the heart).

Save image/video:

Allows the operator to save a still image as well as video clips of a scan. This function is particular to each ultrasound manufacturer, and the user manual should be consulted to learn how to perform this. Although image archiving and recording is not explicitly required for CPoCUS certification, it is often necessary for local or jurisdictional quality assurance or billing systems.

Artefacts:

Refraction/edge artifact: Ultrasound beams are ‘bent’ away from the sides of fluid-filled structures with bright echogenic walls (e.g. aorta, bladder, kidney) resulting in a linear black shadow extending tangentially from the edge of these structures into the far field. It is essential not to mistake this artifact for free fluid.
Acoustic shadow artifact: Ultrasound beams do not penetrate very dense tissues (e.g. bone) resulting in a black shadow in the area beyond these tissues, into the far field. This artifact is very helpful in identifying some landmarks (e.g. spine in the aortic scan and ribs for the pneumothorax scan) but can also be a significant hindrance at other times (e.g. rib shadows obscuring the interface in the upper quadrant scan).
Enhancement artifact: Fluid-filled structures do not impede the beams traveling through the fluid. The tissues far field to this fluid reflect more energy back to the probe and therefore look brighter than adjacent tissues.
Mirror artifact: Structures on the near field side of a highly reflective structure are ‘mirrored’ in the far field. The most common example of this is the mirror image of the liver on the far field side of the diaphragm during a pleural effusion scan.

Scatter:

When the ultrasound beam hits gas, it is scattered in numerous directions. No organized information returns to the probe. The image generated is uninterpretable.

Frequency:

The number of sound waves emitted by the probe in a second. The higher the probe frequency, the shorter the distance between the sound waves, resulting in better clarity (i.e. resolution) of the image on the screen. However, these closely-spaced sound waves do not travel as far (i.e. penetrate) into the body. The lower the frequency, the greater the distance between the sound waves. These widely-spaced sound waves will travel deeper into the body, but the resultant image will have poorer resolution. Almost all modern ultrasound probes have multiple frequency settings. The operator can choose the most appropriate frequency to compensate for tissue variations and for the body habitus of the patient.

Penetration:

The ability of ultrasound waves to travel into the body. The greater the penetration, the farther they travel.

Attenuation:

The degradation of the energy of the ultrasound beam as it passes through tissue. Higher density tissues cause more attenuation.

Reflection:

The return of ultrasound waves back towards the probe. Highly reflective structures will be brighter on the screen as more energy is returned to the probe.

Resolution:

The degree to which ultrasound waves are able to distinguish whether adjacent structures are separate, rather than being one large object. Improving axial resolution allows the operator to distinguish between two structures that are parallel to the ultrasound beam (on top of each other from near to far field). Axial resolution is dependent on the frequency of the probe. Improving lateral resolution allows the operator to distinguish between two structures that are perpendicular to the ultrasound beam (next to each other from side to side). Lateral resolution is improved by moving the location of the focus.

B-mode:

Also known as greyscale. Almost all POCUS scanning is done in this mode. The image is created by reflected sound waves returning to the probe.

M-mode:

Movement mode. A graphic representation created from a B-mode image where movement along one straight line going from near to far field is displayed over time. This allows the operator to see the movement of tissues away from and towards the probe over time, and to measure the distance the tissue moves. M-mode can also be used to measure the rate of movement of tissues (e.g. fetal heart rate in the first trimester scan). The use of this control is NOT required for CPoCUS CORE certification.

Slide:

Moving the probe left-to-right, cephalad-caudad, or anterior-posterior while maintaining the same orientation of the indicator and the handle, with respect to the patient.

Sweep:

Tilting the probe from side to side, perpendicular to the plane of the beam, while keeping the same point of contact on the patient. Also called tilting or fanning.

Rotate:

Turning or twisting the probe on the long axis of the handle clockwise or counter-clockwise, while keeping the same point of contact on the patient and the same view of the area of interest. This a very difficult maneuver for beginners and often results in movement of the probe face and loss of the area of interest on the screen. One can minimize this by rotating the probe slowly, holding the tail of the probe with the opposite hand while rotating, and sliding the probe slightly from side to side during rotation to keep the area of interest in view.

Heel:

Rocking the probe from the indicator side to the non-indicator side or vice versa (i.e. parallel to the beam) while keeping the same point of contact on the patient. Also called heeling/toeing.

Curved array probe (curvilinear or abdominal):

A low-frequency probe with a broad and curved footprint, producing a pie-wedge-shaped image (missing a bite at the apex) with a beam angle of less than 90 degrees. This probe has good lateral resolution and excellent penetration. This probe is ideal for all CORE indications other than trans-vaginal scanning, with the caveat that images in the first 1-2 cm of the near field cannot be interpreted. This is the ‘dead zone’, caused by the coalescence of information returning to the probe face. This probe should not be used for superficial scans requiring very near field image interpretation.

Linear array probe (vascular):

A high-frequency probe with a narrow linear footprint producing a rectangular image. This probe has no dead zone, excellent axial resolution but poor penetration. It should be considered the probe of choice for pneumothorax scanning, vascular access and troubleshooting a small superficial yolk sac in first trimester scans.

Phased array probe (cardiac):

A low-frequency probe with a small footprint producing a pie-wedge-shaped image. It is ideal for narrow spaces as it was designed to fit in between ribs for transthoracic cardiac scanning. However, this probe has poor lateral resolution in the far field and less penetration than the curvilinear probe. It can be used as an alternative probe in thin patients and children for most CORE indications, with the appropriate preset utilized (i.e. abdominal versus cardiac).

Endocavitary probe (transvaginal):

A mid-frequency probe with a small curved footprint producing a wide pie-wedge-shaped image (again with a bit out of the apex, but this time with a beam angle of greater than 90 degrees). This probe has excellent resolution and average penetration.

Appropriate use of and storage of gel:

Getting the best acoustic contact, with the right amount of gel between the probe and the patient’s skin, is critical for good image generation. The gel must be stored on the ultrasound machine and readily accessible. Clinicians must not warm the gel as this may lead to bacterial overgrowth.

Probe cover use:

Probe covers are necessary for sterile procedures and all transvaginal scans. The gel should be placed in between the probe and the probe cover, and gel (or sterile lubricating jelly for transvaginal scans) should be placed on the outside of the cover. Covers should be removed and discarded after each use.

Plugging/docking into power supply:

This should be standard practice after each scan and should be performed by the clinician performing PoCUS. As many systems have long start-up times, leaving ultrasound machines unplugged with dead batteries could have detrimental effects on patient care in emergent situations.

Probe docking/storage:

Handle the probe with care at all times as it is one of the most fragile and expensive parts of the ultrasound system. Probes must be returned into the docking area of the ultrasound cart in between use by the clinician performing PoCUS. Endocavitary probes may need to be stored in sterile or protective containers, depending on local policies.

Cleaning probes and system:

Cleaning the probe between each use is essential. Removing debris / organic tissue, probe covers and disinfecting the probes and ultrasound systems, according to manufacturer specifications and local infection control policies, should be performed by the clinician performing PoCUS, whenever possible*.

*Endocavitary probes:

These probes are often cleaned and disinfected using complex protocols and equipment. Local hospital policies will dictate how endocavitary probes are handled and cleaned between uses. Regardless of disinfection practices, the use of endocavitary probes for PoCUS should not be restricted to the radiology department because of infection control policies and should be available to all hospital clinicians regardless of location. Disinfection procedures should allow turnaround times of 2 hours or less for non-urgent needs and 30 minutes or less for urgent requirements.

Accéder à la version française

Advanced skills for certification

Primary authors
Isabel Alonzo-Proulx
Jean-Michel Cérat
Geneviève Dallaire
Hugo Lamontagne

Editors
Geneviève Dallaire
Greg Hall
Troy Neufeld
Chau Pham
Aaron Webb

Publishing
Sharon Oleskevich

© Canadian Point of Care Ultrasound Society 2019
Reproduction or distribution without express written permission is prohibited

CERTIFY OTHERS

To certify others as an AC MSK Independent Practitioner (IP),
an examiner may submit an IP Request

only if:

The IP candidate has completed introductory training, acquired logged scans, and passed all three AC MSK examinations

and

The examiner is certified as a AC MSK Track Instructor or AC MSK Master Instructor in the modules relevant to the exams

If you cannot see the button below, you have not met the examiner certification criteria

SCAN DOCUMENTATION

The summary below is taken from the curriculum Determinate scan requirements and Certification for each module.

For all Prerequisites, the introductory scans do not count towards certification and do not need to be determinate.

For all Logged scan requirements, there is no requirement for a minimum number of positive scans.

*An ‘unassisted’ scan is one in which the learner generates a determinate image and uses appropriate troubleshooting maneuvers without ANY assistance (verbal or physical) from the instructor.

Dislocation

Dislocation-Shoulder-GHJ (also applies for Effusion-Shoulder-GHJ)

Prerequisites

Appropriate didactic and practical introduction to technique that must include written materials covering all relevant ultrasound physics, anatomy and theory, a minimum of 30 minutes of live or on-line lectures, and at least 5 introductory supervised GHJ scans.

Logged scan requirements

8 GHJ determinate scans supervised by a CPoCUS AC MSK Track Instructor.
Determinate scans are defined in ‘Determinate scan requirements’.
A minimum of 1 scan must be done ‘unassisted’*.

Effusion

Effusion-Elbow-Olecranon fossa

Prerequisites

Logged scan requirements

5 elbow (olecranon fossa) determinate scans supervised directly by a CPoCUS AC MSK Track Instructor for the entirety of the scan.
Determinate scans are defined in ‘Determinate scan requirements’.
A minimum of 1 scan must be done ‘unassisted’.*

Effusion-Wrist-RCJ (also applies for Fracture-Wrist-DR)

Prerequisites

Logged scan requirements

5 wrist RCJ/DR determinate scans supervised directly by a CPoCUS AC MSK Track Instructor for the entirety of the scan.
Determinate scans are defined in ‘Determinate scan requirements’.
A minimum of 1 scan must be done ‘unassisted’.*

Effusion-Hand-MCPJ (also applies for Tendon-Hand-FTS)

Prerequisites

Logged scan requirements

5 hand MCPJ/FTS determinate scans supervised directly by a CPoCUS AC MSK Track Instructor for the entirety of the scan.
Determinate scans are defined in ‘Determinate scan requirements’.
A minimum of 1 scan must be done ‘unassisted’.*

Effusion-Hip

Prerequisites

Logged scan requirements

8 hip joint determinate scans supervised directly by a CPoCUS AC MSK Track Instructor for the entirety of the scan.
Determinate scans are defined in ‘Determinate scan requirements’.
A minimum of 1 scan must be done ‘unassisted’.*

Effusion-Knee-SPR

Prerequisites

Logged scan requirements

6 knee SPR determinate scans supervised directly by a CPoCUS AC MSK Track Instructor for the entirety of the scan.
Determinate scans are defined in ‘Determinate scan requirements’.
A minimum of 1 scan must be done ‘unassisted’.*

Effusion-Ankle-Tibiotalar

Prerequisites

Logged scan requirements

6 ankle tibiotalar joint determinate scans supervised directly by a CPoCUS AC MSK Track Instructor for the entirety of the scan.
Determinate scans are defined in ‘Determinate scan requirements’.
A minimum of 1 scan must be done ‘unassisted’.*

Effusion-Foot-MTPJ

Prerequisites

Logged scan requirements

2 First MTPJ determinate scans supervised directly by a CPoCUS AC MSK Track Instructor for the entirety of the scan.
Determinate scans are defined in ‘Determinate scan requirements’.
A minimum of 1 scan must be done ‘unassisted’.*

Tendon

Tendon-Ankle-Achilles

Prerequisites

Logged scan requirements

8 Achilles determinate scans supervised directly by a CPoCUS MSK AC Track Instructor for the entirety of the scan.
Determinate scans are defined in ‘Determinate scan requirements’.
A minimum of 1 scan must be done ‘unassisted’.*

Fracture

Fracture-Sternum

Prerequisites

Logged scan requirements

4 sternum determinate scans supervised directly by a CPoCUS AC MSK Track Instructor for the entirety of the scan.
Determinate scans are defined in ‘Determinate scan requirements’.
A minimum of 1 scan must be done ‘unassisted’.*

Fracture-Humerus

Prerequisites

Logged scan requirements

3 humeral shaft determinate scans supervised directly by a CPoCUS AC MSK Track Instructor for the entirety of the scan.
Determinate scans are defined in ‘Determinate scan requirements’.
A minimum of 1 scan must be done ‘unassisted’.*

Fracture-Femur

Prerequisites

Logged scan requirements

3 femoral shaft determinate scans supervised directly by a CPoCUS AC MSK Track Instructor for the entirety of the scan.
Determinate scans are defined in ‘Determinate scan requirements’.
A minimum of 1 scan must be done ‘unassisted’.*

Soft tissue

Soft tissue-Layers

Prerequisites

Logged scan requirements

2 soft tissue layers determinate scans supervised directly by a CPoCUS AC MSK Track Instructor for the entirety of the scan.
Determinate scans are defined in ‘Determinate scan requirements’.
A minimum of 1 scan must be done ‘unassisted’.*

Soft tissue-Foreign body

Prerequisites

Logged scan requirements

2 soft tissue foreign body determinate scans supervised directly by a CPoCUS AC MSK Track Instructor for the entirety of the scan.
Determinate scans are defined in ‘Determinate scan requirements’.
A minimum of 1 scan must be done ‘unassisted’.*

CPoCUS AC MSK documentation standards

Use consistent and unambiguous documentation standards to describe the results of your ultrasound examination.
Be aware that these documentation standards emphasize the distinction between your examination and examinations performed in the Diagnostic Imaging department.
Understand that the documentation standards are binary to encourage staying within the limits of your competence.
If a result is neither positive or negative for any reason, it should be documented as indeterminate. The first aim of POCUS is to never declare a false-positive or a false-negative which highlights the importance of documenting a result as indeterminate.

Dislocation

Dislocation-GHJ:
GHJ dislocation positive (specify anterior or posterior)

GHJ dislocation negative
GHJ dislocation indeterminate

GHJ effusion positive

GHJ effusion negative

GHJ effusion indeterminate

Effusion

Effusion-Elbow-Olecranon fossa:

Elbow joint effusion positive
Elbow joint effusion negative
Elbow joint effusion indeterminate

Effusion-Wrist-DR-RCJ:

RCJ effusion positive
RCJ effusion negative
RCJ effusion indeterminate

Effusion-Hand-MCPJ+FTS:

MCPJ space effusion positive
MCPJ space effusion negative
MCPJ space effusion indeterminate

FTS positive
FTS negative
FTS indeterminate

Effusion-Hip:

Hip effusion positive
Hip effusion negative
Hip effusion indeterminate

Effusion-Knee-SPR:

Knee effusion positive
Knee effusion negative
Knee effusion indeterminate

Effusion-Ankle-Tibiotalar:

Ankle joint effusion positive
Ankle joint effusion negative
Ankle joint effusion indeterminate

Effusion-Foot-MTPJ:

First MTPJ effusion positive
First MTPJ effusion negative
First MTPJ effusion indeterminate

Tendon

Tendon-Ankle-Achilles:
Achilles tendon tear positive
Achilles tendon tear negative
Achilles tendon tear indeterminate

Tendon-Hand-MCPJ+FTS:

MCPJ space effusion positive
MCPJ space effusion negative
MCPJ space effusion indeterminate

FTS positive
FTS negative
FTS indeterminate

Fracture

Fracture-Sternum:

Sternal fracture positive
Sternal fracture negative
Sternal fracture indeterminate

Fracture-Humerus:

Humeral shaft fracture positive
Humeral shaft fracture negative
Humeral shaft fracture indeterminate

Fracture-Wrist-DR:

DR fracture positive
DR fracture negative
DR fracture indeterminate

Fracture-Femur:

Femoral shaft fracture positive
Femoral shaft fracture negative
Femoral shaft fracture indeterminate

Soft tissue

Soft tissue-Layers:

Cellulitis positive
Cellulitis negative
Cellulitis indeterminate

Abscess positive

Abscess negative
Abscess indeterminate

Necrotizing fasciitis positive

Necrotizing fasciitis negative

Necrotizing fasciitis indeterminate

Soft tissue-Foreign body:

Foreign body positive
Foreign body negative
Foreign body indeterminate

Image capture

While a still image may be required for billing in some jurisdictions, the use of hard copy for negative image capture for clinical purposes is strongly discouraged, for two reasons:

Image capture blurs the distinction between POCUS and formal ultrasound. POCUS should be considered an extension of the physical exam. As such, it should be documented in the same manner as cardiac auscultation or fundoscopy: a notation in the chart.
Still images cannot be relied upon to determine a true negative scan. This requires a dynamic scan, during which the entire Area of Interest is swept by the ultrasound beam. As an extension of the physical exam, POCUS should be performed at a much lower threshold than for radiology-perfomed studies. Inevitably, this will mean that the vast majority of POCUS studies will be negative. Hard copies will therefore not only be misleading, but also wasteful.

The use of hard copy for image capture is useful for positive studies. Such images should be shown to other physicians involved in the patient’s care and should become part of the patient’s record.

Video archiving

As archiving systems become more widely disseminated, CPoCUS will make specific recommendations regarding the use of video archiving for quality assurance purposes.

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