CT Angiography Pattern Recognition

Systematic Interpretation of CT Angiography

CTA provides detailed vascular anatomy and pathology assessment. This guide covers systematic interpretation for head-to-toe angiography with key recognition patterns.

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1. Technical Considerations

A. Protocol Optimization

• • Contrast: 350-370 mgI/mL, 4-5 mL/s injection rate
• • Timing: Bolus tracking (threshold 100-150 HU)
• • Slice thickness: ≤1 mm for reconstructions
• • Reconstructions: MPR, MIP, VRT essential

B. Artifact Recognition

• • Beam hardening (calcium, stents)
• • Motion artifacts (pulsation, breathing)
• • Inadequate contrast opacification

2. Systematic Interpretation Approach

A. Vascular Anatomy Evaluation

• • Lumen: Patent vs. stenosis/occlusion
• • Walls: Atheroma, dissection, calcification
• • Diameter: Aneurysms (>1.5x normal)
• • Branches: Anatomic variants

B. Pathologic Patterns

• • Atherosclerosis: Eccentric wall thickening
• • Dissection: Intimal flap, double lumen
• • Vasculitis: Concentric wall thickening
• • Embolism: Abrupt cutoff

3. Anatomic-Specific Evaluation

Vascular Territory

Key Structures

Pathologies

Cerebral

Circle of Willis, MCA, ACA, PCA

Aneurysm, AVM, Vasospasm

Carotid

CCA bifurcation, ICA, ECA

Stenosis, Dissection, FMD

Thoracic Aorta

Root, Arch, Great vessels

Dissection, Aneurysm, Coarctation

Pulmonary

Main PA, Segmental branches

PE, Arteriovenous malformation

Abdominal

Aorta, Visceral branches

AAA, Stenosis, Endoleak

Peripheral

Iliac, Femoral, Runoff vessels

PAD, Thrombosis, Embolism

4. Pathology Recognition Guide

A. Atherosclerosis

• • Features: Eccentric plaque, calcification, positive remodeling
• • Grading: <50%: Mild, 50-70%: Moderate, >70%: Severe

B. Dissection

• • Features: Intimal flap, double lumen, wall hematoma
• • Classification: Stanford A/B, DeBakey I-III

C. Aneurysm

• • Features: Focal dilation >1.5× normal, thrombus common
• • Management: <5cm: Monitor, >5cm: Repair

5. Reporting Checklist

1. 1. Contrast opacification adequacy
2. 2. Vessel patency (stenosis grading if present)
3. 3. Wall abnormalities (atheroma, dissection)
4. 4. Aneurysm/pseudoaneurysm measurement
5. 5. Branch vessel involvement
6. 6. Collateral circulation assessment
7. 7. Incidental findings (organs, soft tissues)

CTA provides rapid, high-resolution vascular assessment. Always correlate with clinical context and consider supplementary imaging (DSA, MRA) when needed.

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