TEM classification (aortic dissection)

Components

T — Type (proximal involvement)

• A: Ascending aorta involved (± arch/descending)
• non-A non-B: Arch (± descending) with ascending spared
• B: Descending aorta only (origin distal to left subclavian artery)

E — Entry (primary tear site)

• E0: No entry identified
• E1: Root/ascending aorta
• E2: Arch
• E3: Descending aorta (distal to arch)

M — Malperfusion (end-organ ischaemia)

• M0: None
• M1: Coronary
• M2: Supra-aortic branches (e.g., carotid/vertebral)
• M3: Spinal cord / visceral / renal / limb

Tip: State the organ if known (e.g., M2 carotid, M3 renal). Some centres add “+” for clinical malperfusion (e.g., M2+).

How to read

• Confirm ECG-gating/phase, contrast timing, and op note/TTE (transthoracic echo) if available
• Identify intimal flap, true vs false lumen, entry tear (E1–E3 or E0)
• Map branch-vessel origins from true vs false lumen
• Screen for malperfusion (bowel/renal hypoperfusion, carotid signs, spinal cord risk) and pericardial haemorrhage

Report skeleton (cardio-CT)

• Indication/technique: gating, phase, contrast, key limitations
• Aorta: type (T), dissection/IMH/PAU, pericardium
• Entry: E0/E1/E2/E3 (location); secondary tears if present
• Branch vessels: origin (true/false), stenosis/occlusion
• Malperfusion: M0–M3 + organ(s); clinical “+” if applicable
• Impression: “Aortic dissection: T __ / E__ / M__ (Stanford __). So-what/action: __. Confidence: __ because __.”

Examples

• T B / E3 / M0 → Stanford B; entry descending; no malperfusion
• T A / E2 / M0 → Ascending involved (Type A) with arch entry
• T non-A non-B / E2 / M2+ (carotid) → Arch-entry dissection; clinical neuro signs
• T B / E3 / M3 (renal, limb) → Descending entry; renal + limb malperfusion

Pitfalls & “uncertain” lines

• Motion/poor opacification: “Uncertain—because motion/contrast timing limits assessment of entry/malperfusion.”
• Arch-only disease: call non-A non-B explicitly; management varies.
• Do not infer malperfusion from lumen patency alone—look for end-organ effects; add “+” only with clinical evidence.

Quick checklist (before read-out)

• Stanford A vs B decided?
• Entry site labelled (E0–E3)?
• End-organ status screened and stated (M0–M3 ± organ, “+” if clinical)?
• Pericardium checked? Branch-vessels mapped? Grafts/stents noted?