1.3 Blueprint Domains and Weighting
Key Takeaways
- The VT content outline has 7 domains; Pathology, Perfusion, and Function is the single largest at 32%.
- Normal Anatomy (21%), QA/Safety/Physical Principles (14%), and Physiologic Exams (12%) together with Pathology make up about 79% of the exam.
- Surgically Altered Anatomy (6%) and Ultrasound-guided Procedures (7%) are low weight but still decide borderline passes.
- Allocate study time by weight first, then adjust upward for your diagnostic weak spots.
1.3 Blueprint Domains and Weighting
The ARDMS VT content outline is the exam map. It does not reveal live questions, but it defines the tasks and knowledge areas item writers may test, and it publishes the exact percentage weight of each domain. Verified weights for 2026 are below; confirm against the official outline.
The seven domains and weights
| Domain | Weight | What it covers |
|---|---|---|
| Pathology, Perfusion, and Function | 32% | Carotid/cerebrovascular disease, peripheral arterial disease (PAD), deep vein thrombosis (DVT), venous insufficiency, visceral/renal/mesenteric pathology |
| Normal Anatomy, Perfusion, and Function | 21% | Cerebrovascular, peripheral arterial, peripheral venous, and abdominal/visceral anatomy and normal hemodynamics |
| QA, Safety, and Physical Principles | 14% | Doppler physics, hemodynamics, image optimization, artifacts, ALARA, quality assurance |
| Physiologic Exams | 12% | Segmental pressures, ankle-brachial index (ABI), pulse volume recording (PVR), photoplethysmography (PPG), exercise/stress testing |
| Preparation, Documentation, Communication | 8% | Indications/contraindications, patient prep, protocols, reporting, communication |
| Ultrasound-guided Procedures/Intraoperative | 7% | Access guidance, pseudoaneurysm compression/thrombin injection, intraoperative duplex |
| Surgically Altered Anatomy and Pathology | 6% | Bypass grafts, stents, AV fistula/graft for dialysis, endovascular (EVAR) repair surveillance |
Where the points concentrate
Pathology (32%) plus Normal Anatomy (21%) equal 53% of the exam, all of it grayscale, color, and spectral Doppler interpretation. Add QA/Physical Principles (14%) and Physiologic Exams (12%) and you reach about 79%. If your duplex interpretation and velocity-criteria knowledge are strong, you are positioned for the bulk of the test. The two smallest domains, Surgically Altered Anatomy (6%) and Ultrasound-guided Procedures (7%), are easy to neglect, yet near the 555 cut line, four or five missed easy items in a small domain can decide a pass.
A practical allocation rule
Start by mirroring the weights: spend roughly a third of your time on pathology, a fifth on normal anatomy/hemodynamics, and so on. Then overlay your diagnostic misses. If practice sets show repeated errors in venous insufficiency reflux criteria or ABI calculation, raise those even though their parent domains are mid-weight.
Anchor the high-weight content to numbers
The pathology domain is largely threshold knowledge. Keep a one-page table of decision values you must know cold:
- ICA >70% stenosis: peak systolic velocity (PSV) >230 cm/s, end-diastolic velocity (EDV) >100 cm/s, ICA/CCA ratio >4.0.
- ICA 50-69%: PSV 125-230 cm/s.
- Resting ABI: >1.0 normal, 0.9-1.0 borderline, <0.9 PAD, <0.4 severe/critical limb ischemia.
- Venous reflux: retrograde flow lasting >0.5 s (superficial) or >1.0 s (deep/femoropopliteal).
Mapping anatomy and pathology together
The Normal Anatomy (21%) and Pathology (32%) domains are best studied as paired opposites rather than separate units. For each vascular bed, learn the normal waveform first, then the diseased deviation. In the carotids, the normal internal carotid artery (ICA) shows a low-resistance waveform with continuous forward diastolic flow, while the external carotid artery (ECA) is high-resistance with sharp systolic peaks and little diastolic flow; disease then appears as elevated velocities and spectral broadening. In the legs, normal peripheral arteries are triphasic, and PAD progressively flattens them to biphasic then monophasic.
Studying normal and abnormal side by side turns two large domains into one coherent picture and roughly half the exam.
The physiologic-exam domain rewards arithmetic
Physiologic Exams (12%) is the most calculation-heavy domain and a frequent source of avoidable misses. You must be able to compute an ABI by dividing the higher ankle pressure by the higher brachial pressure, interpret segmental pressure drops of 20-30 mmHg between adjacent levels as a localizing sign of disease, and recognize the loss of the dicrotic notch on pulse volume recording (PVR) waveforms. Photoplethysmography (PPG) and toe pressures matter when ankle vessels are calcified and noncompressible (ABI >1.4). Practice these as timed math, not as concepts.
Surgically altered anatomy: small but distinctive
The 6% Surgically Altered Anatomy domain tests recognition of bypass grafts, stents, endovascular aneurysm repair (EVAR) surveillance, and dialysis access. Key facts include normal arteriovenous (AV) fistula volume flow targets (generally >500-600 mL/min for adequacy) and the surveillance criteria for graft stenosis (focal velocity elevation, typically a velocity ratio >2.0 across a narrowing). These are high-yield because they are specific and rarely confused with other domains once learned.
Blueprint tracker
For each domain, mark four readiness states: understand, can apply, can calculate or decide under time, and can explain why distractors are wrong. A domain is not done until all four are checked. Revisit the heaviest domains (Pathology, Anatomy) in every weekly cycle, and rotate the smaller domains so none goes untouched for more than a week.
The Preparation, Documentation, Communication domain
The 8% Preparation, Documentation, and Communication domain is easy to underrate but high-yield because the rules are concrete. It covers correct indications and contraindications, patient preparation (for example, fasting before a mesenteric or renal artery duplex to reduce bowel gas), informed-consent expectations, standardized scanning protocols, accurate labeling and measurement documentation, and communicating critical findings such as a newly detected proximal deep vein thrombosis to the ordering clinician promptly.
Item writers like this domain because the answers are policy-aligned and defensible: choose the option that follows protocol, protects the patient, and produces a clean, complete record. When two answers seem clinically reasonable, favor the one that documents the finding and escalates appropriately.
Which VT content domain carries the largest single percentage weight on the exam?
A candidate scores well on pathology and normal anatomy but consistently misses items on bypass grafts and AV dialysis access. What is the best response given the blueprint?