ARRT Sonography common mistakes
ARRT Sonography · Understand the traps and how to avoid them.
Picks the highest-frequency transducer available to "get better resolution," then compensates for the poor penetration on a deep structure by cranking up overall gain and output power.
The candidate memorized "higher frequency equals better resolution" as an isolated fact and never paired it with the attenuation/penetration trade-off, so depth is ignored when selecting the probe.
What to do instead
Before choosing a transducer, estimate the required penetration depth and pick the highest frequency that reaches it; then optimize the image with harmonics, focal zone placement and TGC rather than with output power. State the rule to yourself as: axial resolution improves with frequency, penetration falls with frequency.
Labels every dark band behind a structure as "shadowing" and every bright band as "enhancement" without checking what the structure actually attenuates, and accepts a mirror-image or edge-shadow artifact as a real second structure or mass.
Artifacts are studied as a list of names rather than as predictable consequences of beam physics, so the candidate pattern-matches the appearance instead of reasoning about the mechanism (reflection, refraction, attenuation difference, propagation speed error).
What to do instead
For each artifact, store a mechanism plus a disproof test: mirror image vanishes when the reflecting interface is moved out of the beam path; edge (refraction) shadowing sits at a curved border and does not follow a real attenuating structure; enhancement occurs behind a fluid-filled, low-attenuation structure. Practice assigning a mechanism before assigning a name.
When color does not fill a vessel, keeps raising color gain until the color bleeds outside the vessel wall; or, when the spectral trace wraps around, lowers gain instead of changing the scale.
Aliasing and overgain are both perceived as "the Doppler is not working," so the candidate applies the wrong control and never links the wrap-around to the Nyquist limit (PRF/2).
What to do instead
Learn the aliasing correction set in order: increase the velocity scale/PRF, lower the transmitted frequency, shift the baseline, steepen the Doppler angle, or switch to continuous wave. Learn that increasing gain fixes weak signal, never aliasing, and that overgain produces color outside the vessel.
Treats every probe the same way between patients, wiping an endocavitary probe with a low-level surface wipe or using a disinfectant not approved for the probe, rather than applying the correct disinfection level for the contact type.
Disinfection is memorized as "clean the probe" instead of as a classification exercise (noncritical, semicritical, critical contact), and endocavitary probes are mentally grouped with abdominal probes.
What to do instead
Anchor each probe to a contact category: skin-contact probes need low-level disinfection; probes contacting mucous membranes (endocavitary, transesophageal) are semicritical and need high-level disinfection plus a probe cover; sterile contact needs sterile technique. Confirm the disinfectant's contact time and compatibility on the label.
Completes the protocol, writes the report, and lets the patient leave without escalating an immediately actionable finding such as a suspected ruptured ectopic pregnancy, a large abdominal aortic aneurysm, or new deep venous thrombosis.
The candidate separates "scanning" from "communicating" and assumes the reading physician will catch it later, so no critical-results pathway is triggered at the time of the exam.
What to do instead
Maintain a short critical-findings list and rehearse the escalation script: identify the finding, notify the supervising/reading physician or covering clinician by the facility's defined route, document who was notified and when, and confirm the patient is not released before handoff.
Reports the abdominal aorta as normal without an actual measurement, or measures it inner-wall to inner-wall or in a longitudinal plane only.
The measurement is treated as optional when the vessel "looks fine," and the wall-to-wall convention is not tied to how aneurysm size is defined and followed over time.
What to do instead
Measure the aorta outer-wall to outer-wall, anterior-posterior, in the transverse plane, at proximal, mid and distal segments; use longitudinal views for plaque and branch evaluation but not for the diameter call. Report the number, not just the impression.
Calls the common bile duct dilated without measuring it, or measures across the wrong walls or mistakes the hepatic artery or portal vein for the duct at the porta hepatis.
The porta hepatis is a cluster of tubular structures and the candidate has not fixed the landmarks (duct anterior to the portal vein, hepatic artery to the left) or the measurement convention.
What to do instead
Identify the duct by its relationship to the portal vein and hepatic artery, confirm with color Doppler that the structure has no flow, and measure inner-wall to inner-wall at the level of the porta hepatis. Memorize the normal upper limit and the expected age-related and post-cholecystectomy widening.
Obtains fetal biometry in whatever plane shows the structure largest, e.g., an oblique head plane for BPD/HC, an abdominal plane missing the portal sinus or stomach, or a femur measurement that includes the distal epiphysis.
Each measurement is learned as "find the structure and measure it" instead of as a set of required anatomic landmarks that define the correct plane.
What to do instead
Tie each measurement to its landmark checklist: BPD/HC at the level of the cavum septi pellucidi and thalami with the midline continuous; AC at the level of the stomach bubble and portal sinus in a true transverse plane; femur along the ossified shaft only, excluding the epiphysis. Recite the checklist before measuring.
Sees a fluid collection within the uterus on a first-trimester scan and calls it a gestational sac, then rules out ectopic pregnancy on that basis.
Any intrauterine fluid is treated as a sac, and the distinguishing criteria (decidual reaction, sac position, contents, shape) are not applied systematically.
What to do instead
Apply the discriminating criteria: a true gestational sac is eccentrically located within the endometrium, shows the double decidual sign, and contains a yolk sac; a pseudogestational sac is central, conforms to the cavity, and lacks a yolk sac. Correlate with hCG level and, when the location is uncertain, keep ectopic pregnancy in the differential and say so.
Evaluates a painful scrotum with color Doppler at default high-flow settings, does not compare with the contralateral side, and documents "flow present" without assessing whether flow is symmetric and adequate.
Default machine presets are built for larger vessels, so low testicular flow is missed, and the contralateral testis is not used as the internal control.
What to do instead
Use power Doppler or color with a low velocity scale, low wall filter, and optimized gain, image both testes with identical settings, and compare side to side. Document presence, symmetry and character of intratesticular flow; if torsion is suspected, escalate immediately rather than waiting for the report.