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Boonprasit Kritpracha, MD Department of Surgery, Prince of Songkla University Aortic Aneurysm Morphology Imaging: A Key to Success Planning for EVAR... Vascular Surgery Exposure befor

Boonprasit Kritpracha, MD

Department of Surgery, Prince of Songkla University

Aortic Aneurysm Morphology Imaging:

A Key to Success

Planning for EVAR

Vascular Surgery

Exposure before 1990

Vascular Surgery Exposure after 1990

A Fundamental Shift

Neck Proximal anchoring zone

Iliac arteries Distal “seal” zone

2 important zones

Imaging is Critical AAA Endograft Planning

Patient selection

Device selection – type, ? Extensions

Additional procedures – IIA coil embolization

Bell-bottom procedure

Surveillance

Endoleak,   aneurysm size

Morphological changes – aorta, device

Device failure – migration, wire fracture, etc

Preoperative imaging studies

AAA Endograft Planning

Axial CT Scan Problems

• Slice Thickness

• Axial slice artifact

• Length error

• Measurement process

Slice Thickness 10 mm

Slice Thickness 2 mm

Tortuosity makes neck appear elliptical

Axial Slice Artifact

Ouriel K, Green RM, et al, JVS 1992

Assuming the aortic neck is round

can lead to “axial slice” error

6.7% had not round neck difference > 4 mm

34 of 120 cases aortic neck not round

Axial 28 mm

33 mm

27 mm

32 mm

20 mm

Diameters of Iliac Arteries

Also need reformatted CT slices!!

Axial CT Scan Problems

• Axial slice artifact

• Measurement process

Axial CT Scan Problems

• Axial slice artifact

• Length error

Diameter Measurements

Measuring on small Axial Slices

contributes to exaggerated errors

Clinical Evidence

% Error: 10%+

Error: >+/- 2.5mm

Parallax & Magnification

Important during procedure - up to 3 cm

Can cause endograft failure

Need consistent system of control

AAA diameter is 61 mm

Thrombus effect

Thrombus effect

78 o

Perception of angle depends on projection

Arteriography length measurement artifact

AAA Endograft Planning

CT scan + 3-D reconstruction

2 Cases