What will a CT (Computed Tomography) run-off show?

CT Angiography Run-Off: Comprehensive Vascular Assessment

A CT angiography run-off is a comprehensive vascular imaging study that evaluates the entire arterial system from the abdomen through the pelvis and down to the feet, providing a complete "road map" of the lower extremity arterial circulation to guide treatment decisions for peripheral arterial disease. 1

What the Study Shows

Arterial Anatomy and Pathology

• Visualizes the complete arterial tree including the abdominal aorta, iliac arteries, femoral arteries, popliteal arteries, and all tibial vessels down to the foot arteries 1, 2
• Detects stenoses and occlusions with 90-100% sensitivity and specificity for lesions >50% diameter, comparable to catheter angiography 1
• Identifies arterial occlusions, stenoses, aneurysms, dissections, and thromboembolic disease throughout the lower extremity arterial system 1, 3
• Shows collateral vessels and arteries distal to occlusions that may not appear on conventional catheter angiography due to the volumetric acquisition 1

Vessel Wall and Plaque Characteristics

• Demonstrates atherosclerotic plaque burden and calcification within vessel walls, though heavily calcified tibial arteries can limit interpretation 1
• Reveals vascular lesions associated with aneurysms and cystic adventitial disease that projectional catheter angiography cannot detect 1
• Identifies penetrating ulcers, intravascular webs, bands, and organized mural thrombi that suggest chronic thromboembolic disease 1, 4

Treatment Planning Information

• Provides assessment of stenosis length, severity, and number to plan endovascular or surgical revascularization 1, 5
• Evaluates bypass graft patency with excellent accuracy compared to duplex ultrasound 1
• Determines suitability for percutaneous intervention by showing vessel caliber, calcification burden, and runoff quality 5, 2

Advanced Imaging Capabilities

Multiplanar Reconstruction

• Creates multiplanar reformatted and maximum-intensity projection images to generate a detailed arterial road map for procedural planning 1
• Allows visualization from multiple angles to assess eccentric lesions and vessel tortuosity 2

Extravascular Findings

• Detects clinically significant incidental findings including previously unknown malignancies (2.8% incidence in acute limb ischemia patients), abdominal aortic aneurysms, and other pathology 6
• Shows nonvascular pathology such as masses, lymphadenopathy, and bone lesions that may explain symptoms or require treatment 1, 6

Critical Diagnostic Features

Acute Vascular Emergencies

• Identifies acute arterial thrombosis or embolism causing acute limb ischemia, which requires rapid diagnosis for limb salvage 3
• Detects traumatic vascular injuries including vessel transection, pseudoaneurysms, active extravasation, and arteriovenous fistulas 3
• Shows peripheral aneurysms with thrombosis or embolization as causes of acute ischemia 3

Chronic Disease Assessment

• Evaluates extent of atherosclerotic disease using TASC classification to guide treatment selection between endovascular and surgical approaches 5, 7
• Identifies predictors of intervention failure including poor tibial runoff, external iliac artery disease, and presence of distal bypass grafts 5
• Detects signs of chronic thromboembolic pulmonary hypertension when performed as part of pulmonary evaluation, though this is a different indication 1

Important Clinical Considerations

Diagnostic Confidence

• Provides sufficient diagnostic confidence for treatment decisions in 97% of chronic PAD patients and 100% of acute PAD patients 8
• Reliability of treatment decisions is superior for chronic PAD (92%) compared to acute PAD (82%) 8

Limitations to Recognize

• Heavily calcified tibial arteries reduce diagnostic accuracy, particularly in patients >80 years old, diabetic, or on dialysis 1
• Non-diagnostic image quality occurs more frequently in calf (17-28%) and foot arteries (20-52%) compared to proximal vessels 8
• Dual-energy CTA can reduce blooming and beam-hardening artifacts from calcification and metallic stents 1

Advantages Over Alternative Imaging

• More rapid acquisition than MRA with better safety in patients with pacemakers or defibrillators 1
• Less susceptible to metal artifacts than MRI, making it superior for evaluating stented vessels 1
• Avoids claustrophobia issues that limit MRA in some patients 1
• Fewer nondiagnostic studies than ventilation-perfusion scanning for vascular assessment 1