Optimal CTA Reporting for Acute Pulmonary Embolism

A practical radiology review of Optimal CTA Reporting for Acute Pulmonary Embolism, focused on imaging findings, differential diagnosis, reporting points, and high-yield teaching pearls.

• Consensus by ESC, Fleischner, EACVI, ESTI, STR, ERS (2025).

Purpose & Context

• 》CTA = first-line imaging for suspected acute PE.
• ︎Goal: deliver standardized, prognostically relevant, and actionable reports.

How to Perform CTA

• kV: 80–120 (use automatic low-kV selection if possible).
• Flow rate: ≥4 mL/s (5 mL/s ideal) with ≥20 G antecubital IV access.
• Contrast: 80–100 mL (300–370 mg I/mL).
• Rotation time: shortest possible, section thickness: 1 mm.
• Direction: caudo-cranial in dyspneic patients.
• Reconstruction: iterative or deep-learning.
• Pregnancy: reduce kV (80–100), limit z-axis (diaphragm–aortic top).

Common Pitfalls & Fixes

• Poor opacification: wrong ROI or delayed bolus → repeat with ROI in aorta.
• Motion artifacts: use shallow breathing, caudo-cranial direction.
• Transient interruption of contrast: avoid deep inspiration.

Structured Reporting Essentials Include all core findings (Delphi ≥80% consensus)

‼ “Must Haves”

• RV/LV ratio (axial): sign of RV strain.
• Central PE location (main/lobar arteries).
• (Isolated) subsegmental PE (report explicitly).
• Septal deviation (toward LV → RV overload).
• Intravascular webs/bands (chronic PE indicator).
• Pulmonary artery retraction.
• Bronchial artery dilation.
• RV hypertrophy.

“Nice to Haves”

• PA trunk diameter.
• Organized mural thrombi.
• Complete arterial
• occlusion.

Report Structure (Suggested)

• Technique: scanner type, contrast, dose, ECG gating if used.
• Image quality: adequate / suboptimal / nondiagnostic.

3. Findings

• 》Clot presence & location (central/lobar/segmental/subsegmental).
• 》Extent (occlusive/non-occlusive).
• 》Signs of RV dysfunction (RV/LV ratio > 1, septal bowing, reflux).
• 》Chronicity (webs, retraction, bronchial collaterals).
• 》Parenchymal findings (infarcts, mosaic attenuation).
• 》Alternative diagnoses (aortic dissection, pneumonia, etc.).
• Impression: confirm/exclude PE; indicate acute/chronic; comment on RV strain.
• Prognosis/management: mention if findings predict poor outcomes.

Reporting Pearls

• Always measure and state RV/LV ratio numerically.
• Specify whether study is diagnostic or limited.
• Use standardized terminology (acute PE, chronic PE, saddle PE, subsegmental PE).
• If negative, state the level of analyzable arteries (down to segmental/subsegmental).
• Mention possible CTEPH features if present.
• Add structured impression for clinicians (“PE confirmed; RV strain present → intermediate-high risk”).
• Key Takeaway CTA for PE = not just diagnosis of clot, but risk stratification tool.

Report should tell what the clot is, where it is, what it means for prognosis, and what else might be going on.