First and second year — the floor first, then every step
Haemopericardium is the finding that matters: on FAST and CT, look for pericardial fluid of blood attenuation and the signs of tamponade, and in penetrating trauma follow the track to the heart.
Orient first
A small volume of pericardial blood can cause tamponade because the pericardium cannot stretch acutely.
Blunt cardiac injury is usually a clinical and ECG/troponin diagnosis; imaging finds its complications — haemopericardium, septal or valve injury.
A sternal fracture raises the prior for cardiac contusion.
Acquire the study
Arterial and portal venous phase CT; ECG gating reduces motion when available.
The manoeuvre
Pericardial fluid attenuation: blood about 30–70 HU.
Tamponade signs: distended IVC and hepatic veins with reflux, flattened or compressed cardiac chambers ("flattened heart"), periportal oedema.
Pneumopericardium; the track of a penetrating injury to the pericardium.
Myocardial enhancement defects, septal and valve injury on the arterial phase.
What confirms it
Pericardial fluid of blood attenuation or echogenicity in a trauma patient.
What licenses you to exclude it
A small pericardial effusion in trauma is haemopericardium until proven otherwise.
The classic misread
Missing a small haemopericardium on a trauma CT read at a lung or bone window.
Reporting the injury
Classification to use
AAST cardiac injury scale exists; the report states haemopericardium, tamponade signs and myocardial or valvular injury.
Measurements — and how to take them
Maximal pericardial fluid depth in mm; attenuation in HU.
What to report
Pericardial fluid depth and attenuation, tamponade signs, pneumopericardium, myocardial injury, and the relation of any penetrating track to the heart.
How to report it
CT: "Haemopericardium (maximal depth 12 mm, 45 HU) with a distended IVC, contrast reflux into the hepatic veins and flattening of the right ventricle — features of cardiac tamponade."
What not to report
Do not call pericardial fluid "physiological" in a trauma patient.
Associated injuries to look for
Sternal and anterior rib fractures, aortic injury, penetrating chest and upper abdominal wounds.
What changes management
Haemopericardium with tamponade physiology → emergency pericardial decompression / sternotomy.
Reference values
Each value carries the caveat that keeps it from being misused. Normal limits and diagnostic criteria are kept apart on purpose: a disease cut-off read as a normal range is the more dangerous mistake.
Diagnostic criteria
Pericardial effusion · Size grading — echo versus CT
a named distinction: echocardiography grades by centimetre strips in standard views; CT reports depth at a stated location (commonly a few millimetres is physiological, over about 2 cm is large) — the two scales are not the same measurement
A moderate CT effusion can be tamponading if it accumulated fast, and a large chronic one may not. Report depth, distribution (circumferential vs loculated) and mass-effect, and leave tamponade to the bedside.
CT · USG · MRI
See it on real cases
Direct links to Radiopaedia — the reference article and worked cases with their images. Each opens on Radiopaedia.