Pulmonary embolism? (CTPA)

CTAHA/ACC 2026

Dyspnea, chest pain, or unexplained hypoxia; CTPA defines embolus distribution and contributes RV risk information, while treatment escalation depends on integrated clinical severity.

Answer the surgeon

Anticoagulation vs escalation. Report embolus distribution and numeric RV/LV ratio, but systemic lysis or thrombectomy is selected from integrated hemodynamics, respiratory status, clinical severity, biomarkers, RV findings, bleeding risk, and multidisciplinary assessment — not clot burden alone.

Your answer must state:

PE: yes or no
Most proximal extent — saddle / main / lobar / segmental / subsegmental — and laterality
RV strain: RV/LV diameter ratio >1.0, septal flattening or bowing toward the LV, contrast reflux into the IVC and hepatic veins
Lung infarct
If negative: the alternative explanation for the symptoms

Key and direct findings

1.Intraluminal filling defect
A sharply marginated defect within an adequately opacified pulmonary artery; name the most proximal level.
2.RV strain signs
RV/LV diameter ratio >1.0 on the axial or four-chamber view, interventricular septal flattening or bowing toward the LV, and contrast reflux into the IVC/hepatic veins contribute to risk stratification; report them with every positive PE, but do not use CT findings alone to select therapy.

Supportive signs & checks

1.Lung infarct
Peripheral wedge-shaped consolidation, often with central lucency, in the territory of the embolus.
2.Flow and bolus artifacts
Transient interruption of contrast produces ill-defined, single-image, dependent pseudodefects — real emboli are sharp and reproducible.
Pitfall: A fuzzy defect seen on one image only in a poorly opacified artery is bolus timing, not PE.
3.Isolated subsegmental defects
Confirm on two planes and on contiguous images; if uncertain, say so — an overcalled subsegmental PE buys months of anticoagulation.
Pitfall: Respiratory motion makes lower-lobe subsegmental calls unreliable — check the lung windows for motion before committing.
4.Nodes and mucus plugs
Hilar lymph nodes and mucus-filled bronchi are the classic PE fakes — confirm the defect is intra-arterial.

Wet-read snippets

Fill the blanks, then copy into your preliminary report.

Positive

Acute pulmonary embolism, most proximal at the ___ (___ side[s]). RV findings: RV/LV ratio ___, septal bowing ___, IVC reflux ___. Lung infarct: ___.

Negative

Adequate-quality CTPA with no filling defect to the segmental level — no acute PE. Alternative finding: ___.

Equivocal

Possible isolated ___ subsegmental filling defect, not confirmed on orthogonal review — equivocal; correlate clinically ± repeat imaging.

Sources

2026 guideline for the evaluation and management of acute pulmonary embolism in adults — Creager MA et al. J Am Coll Cardiol (2026)
Management of suspected acute PE in the era of CT angiography (Fleischner statement) — Remy-Jardin M et al. Radiology (2007)

Content review: Content pending clinical review · 2026-07-15

Educational reference for trained clinicians. Verify every result against the cited original guideline before use. Not a substitute for clinical judgment or medical advice.