Addendum to below Tables on Aortic Dissection, Chamber Thrombus and Vegetations

Aortic Dissection 

There isn’t a single “fixed” test-characteristic for transthoracic echocardiography (TTE) in aortic dissection—the numbers depend on (1) whether the dissection involves the ascending (Stanford A) or descending (Stanford B) aorta, and (2) how the study defined a “positive” scan (intimal-flap only vs any suggestive sign)

How to interpret these numbers

• High specificity, limited sensitivity. A clearly visualised intimal flap on TTE is highly confirmatory; a negative study—especially when only parasternal/apical windows are obtained—cannot reliably exclude dissection, particularly type B disease.

• Ascending aorta is easier to see. Sensitivity is appreciably better for type A dissections because the proximal aorta and aortic root lie within normal TTE windows. Descending thoracic aorta is often obscured by lung and rib, leading to the much lower sensitivity for type B.

• Technique matters. Adding suprasternal notch views, harmonic imaging, or ultrasound contrast agents, and scanning specifically for any suggestive finding (intimal flap, root dilation, new AR, pericardial effusion) can push sensitivity above 90 %, while preserving high specificity.

• Clinical takeaway. Use TTE as a rapid bedside screen—particularly in haemodynamically unstable patients—knowing that:

• Positive TTE → can expedite surgical/cardiovascular CT confirmation.

• Negative or equivocal TTE → does not rule out dissection; proceed to gated CT angiography or TEE if suspicion remains high.

Vegetations /SBE

Rule of thumb: a positive (clearly mobile) vegetation on TTE is very reliable, but a negative study—especially in prosthetic valves or when image quality is sub-optimal—never rules out infective endocarditis and should be followed by TEE if clinical suspicion is high.

Why the numbers vary

• Vegetation size matters

  • Only ~25 % of vegetations < 5 mm are seen, but ~70 % of those 6–10 mm are detected ccjm.org.

  • Larger, more mobile masses are almost always picked up.

• Image quality & technique

  • Harmonic imaging and contrast agents explain why the recent meta-analysis (61 % sensitivity) out-performs older series from the 1990s (≈45 %).

  • Adding off-axis windows (right parasternal, suprasternal notch) and 3-D sweeps can push sensitivity into the mid-70 % range in experienced labs.

• Valve type

  • Acoustic shadowing from prosthetic material hides small vegetations, so sensitivity drops to ~30–50 %.

  • Conversely, specificity stays high because artefacts that mimic vegetations are well recognised.

Practical take-aways for reporting & patient care

1. Use TTE first for haemodynamically stable patients—it is fast, non-invasive, and will confirm IE in roughly two-thirds of native-valve cases.

2. Escalate to TEE (or gated cardiac CT/PET-CT for prostheses) when:

   • TTE is negative/equivocal but Duke or ESC/ACC clinical likelihood remains high.

   • The patient has a prosthetic valve, intracardiac device leads, prior surgery, or poor acoustic windows.

3. Repeat imaging 3–7 days later if suspicion persists; early vegetations may enlarge and become visible.

4. Document limitations in every negative TTE report: comment on image quality and indicate that small or prosthetic-masked vegetations cannot be excluded.

Bottom line: expect TTE to spot about two-thirds of native-valve vegetations and only one-half (or fewer) of prosthetic-valve vegetations, while maintaining >90 % specificity—hence the need for reflex TEE when the diagnosis still matters.

Any Chamber Thrombus

How to use these numbers in practice

• High specificity across the board – when you see a discrete, echo-dense mass with independent mobility at the expected location, it is very likely a true thrombus and should prompt treatment or confirmatory imaging rather than further scepticism.

• Sensitivity is chamber-dependent:

  • LV thrombus is easiest because the apex is usually in the near field; nevertheless, up to 40 % are still missed without contrast or apical-wall-motion scoring.

  • LA/LAA thrombus is routinely missed on TTE; a negative study never rules it out when the appendage is clinically relevant (e.g., before cardioversion). Proceed to TEE or CT.

  • Right-sided thrombi are rarer and often located in recesses or on hardware. Modified apical/sub-costal views and a focused search improve yield but many series still report only half of RV or 1 in 3 RA thrombi being seen on TTE.

• Contrast & advanced techniques help: LV opacifying agents or harmonic imaging increase sensitivity by ~15 %. There is emerging experience with intracavity contrast for atrial clots, but it is not yet routine.

• Report responsibly: For atrial or right-heart chambers, avoid a blanket “no thrombus” statement unless image quality genuinely excludes it; instead describe the acoustic windows and say “No thrombus seen; small or appendage thrombus cannot be excluded.”

Bottom line:
TTE is a rule-in tool for intracardiac thrombus – a positive finding is trustworthy – but its rule-out value varies: good for LV, modest for LA/LAA, and poor for RA/RV. When missing a clot has therapeutic consequences, reflex to TEE, cardiac CT or CMR.