Quality assurance and lab accreditation

Physics

Sonography labs are only as good as

the equipment within the lab

sonographer performing the study

radiologist reading the studies

QA programs are essential for

patient care

Goals of QA

proper equipment operation

detect gradual changes

minimize downtime

reduce non-diagnostic exams

reduce repeat scans

Gold standard

imaging test that is considered the most accurate test for that type of study

Sensitivity

how good is the test at finding positive exams?

Specificity

how good is the test at deciding if an exam is normal?

Accuracy

how good is the test overall? how good is the test at finding both positive and negative results

Reliability

is the test consistent? does it consistently provide accurate results

Positive predictive value (PPV)

how many abnormal (positive) exams your imaging test correctly identifies as positive

Negative predictive value (NPV)

how many normal (negative) exams your imaging test correctly identifies as normal

Preventative maintenance

routine electrical evaluation to ensure there will be no harm to the sonographer or patient

AIUM suggests all equipment should be evaluated and calibrated

ANNUALLY

Daily operations evaluated by the sonographer

fraying of electrical cords or transducer cords

tears in wiring casing

evaluate the face of the transducer for cracks or chips

evaluate the keyboard for sticky keys

examine the track ball

check for caliper malfunctions or depth adjustments

Performance testing imaging capabilities include:

axial resolution (LARRD)

lateral resolution (LATA)

vertical depth

horizontal calibration

overall registration of data

Performance testing phantoms

calibration and slice-thickness test objects

tissue mimicking phantoms

doppler phantoms

Phantoms are objective standards which means:

they are NOT open to interpretation

Calibration test objects

test the measurement accuracy of the machine

contain strategically located steel pins

speed of sound is identical to soft tissue

does not have attenuation properties

often called the AIUM test object

Test objects evaluate the accuracy and performance of the system:

axial resolution

lateral resolution

caliper accuracy

dead zone

Tissue equivalent phantoms

test objects or grayscale test objects that evaluate a machine’s grayscale sensitivity and contrast resolution

often combined with calibration test objects to create a general purpose phantom

Tissue equivalent phantoms perform very similar to soft tissue:

speed of sound (1.54 km/s)

attenuation

scattering characteristics

echogenicity

grayscale evaluation

Doppler phantoms

test objects are used to evaluate the flow direction, the depth capability of the doppler beam, accuracy of the sample volume location, and measured velocity

Types of doppler phantoms

flow phantom

vibrating string phantom

moving belt phantom

Slice-thickness phantom

1 ½ D transducer!!

evaluates the elevation resolution, or the thickness portion, of the sound beam perpendicular to the imaging plane

measures beam geometry perpendicular to the imaging plane

Accreditation means:

labs have met specific, comprehensive guidelines that govern departmental administration and policies, patient care, scanning protocols, and procedures

AIUM

American institute of ultrasound medicine

AB, small parts, gynecology, OB, vascular

IAC

intersocietal accreditation commission

vascular and echocardiography

ACR

American college of radiology

Ab, gynecology, small parts, OB, and vascular

Professional credentialing organizations

ARDMS - American registry for diagnostic medical sonography

CCI - cardiovascular credential international
ARRT - american registry of radiographic technologists