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Negative CT with High Dissection Suspicion — EECC MCQ

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ModerateGeneral CardiologyNegative CT with High Dissection SuspicionEECC

A 55-year-old man with suspected acute aortic dissection has a negative CT aortography but clinical suspicion remains high (tearing chest pain, aortic regurgitation murmur, pulse deficit). What should be done?

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Correct answer: D — TOE should be performed urgently — CT sensitivity for dissection is ~95-98% but can miss limited dissection flaps, particularly in the ascending aorta; TOE provides complementary information and can be performed at the bedside in unstable patients

While CTCA has excellent sensitivity (~95-98%) for acute aortic dissection, false negatives can occur: (1) small/limited intimal flaps in the ascending aorta; (2) motion artefact (ascending aorta moves with each heartbeat); (3) intramural haematoma without clear flap (may be missed on non-gated scans). When clinical suspicion remains high despite negative CT: (1) TOE — provides excellent real-time imaging of the ascending aorta and arch (sensitivity ~98%, specificity ~95%); can be performed at the bedside in ICU; detects: intimal flap, entry/re-entry tears, aortic regurgitation, pericardial effusion; (2) MRI — highest sensitivity and specificity (~98-99%) but limited by availability, scan time, and patient stability; (3) repeat ECG-gated CT with optimised acquisition. The ESC 2024 Aortic Disease Guidelines recommend that high clinical suspicion should override a single negative imaging study.

Reference: ESC (2024): Aortic Disease Guidelines