Triple-rule-out CT protocols

Acute chest pain arises from various complex causes, often with rapid onset and progression, accompanied by non-specific symptoms and a high mortality rate. It is crucial to identify the underlying cause and promptly address symptoms quickly. Patients experiencing emergency chest pain should undergo ECG, CT scan, ultrasound, and ECT to rule out life-threatening conditions like pulmonary embolism, acute coronary syndrome, or aortic aneurysm/dissection. The swift progression of these conditions can complicate diagnosis and delay treatment.

A triple rule out (TRO) protocol is a cardiac CT protocol that aims to assess for different problems at the same time in one single examination: obstructive coronary artery disease, aortic aneurism or pulmonary embolism.

Clinical implications of combined scanning: A single contrast agent injection enables rapid CTA assessment of the pulmonary artery, coronary arteries, and aorta for early chest pain diagnosis.

1. Pulmonary artery CTA provides detailed visualization from the main pulmonary artery to subsegmental branches to accurately locate pulmonary embolisms including thrombus characteristics.

2. Coronary CTA assesses atherosclerosis levels in coronary arteries while detailing stenosis in major vessels such as the left main coronary artery and its branches.

3. Aortic CTA reveals aortic condition, identifying aneurysms or dissection signs along with rupture extent; it also allows dynamic analysis of true lumen changes over time for better clinical decision-making regarding long-term management of aortic dissection.

The clinical images show male patient, 36Y, who was admitted to the hospital for "upper abdominal pain" and underwent a coronary angiography for screening, which showed aortic dissection. Shortly after the clinicians performed a thoracoabdominal aortography and coronary CTA, which helped diagnose with Stanford type B aortic dissection.

In actual work, the patient's clinical condition should be comprehensively considered. For patients with chest pain, their circulation time, cardiac output, etc. may often change significantly. Different single, double or triple scanning plans can be selected for the pulmonary artery, coronary artery and aorta triple examination of chest pain, therefore the TRO scanning plan has the highest requirements for equipment conditions. In clinical work, different scanning plans should be selected based on the patient's clinical condition, specific examination objectives and requirements, the condition of the CT equipment and even the operator's proficiency.