Aortic Intramural Abnormality

Gregory Kicska, MD, PhD

DIFFERENTIAL DIAGNOSIS

Common

Less Common

Rare but Important

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Helpful Clues for Common Diagnoses

Atherosclerosis/Adherent Thrombus
- Concentric diffuse involvement vs. spiral involvement of intramural hematoma
- Aorta often tortuous with atherosclerotic disease in branch vessels
Aortic Dissection
- Intimal flap readily seen on contrast CT as unenhanced line through lumen
- Intraluminal calcifications on noncontrast CT suggest diagnosis and represent displaced intimal calcifications
- “Beak” sign: False lumen side of dissection flap meets outer wall with acute angle
- “Cobweb” sign: False lumen traversed by media fibers
- Confusion with pulsation artifact at aortic root avoided by inspecting coronal images

Helpful Clues for Less Common Diagnoses

Aortic Intramural Hematoma
- Hyperdense aortic wall compared to lumen when acute, isodense when old
- Check LV chamber for hypodense blood to avoid pitfall of confusion anemia
- Patient more likely to progress to dissection with coexistence of ulcer-like projections
- Most commonly in descending aorta
Penetrating Atherosclerotic Ulcer
- Luminal irregularity
- Must extend beyond expected contour of intima
- Outer aortic wall thickening indicates acuity

Helpful Clues for Rare Diagnoses

Takayasu/Giant Cell Arteritis
- Radiographically indistinguishable, differentiated based on age (Takayasu < 50 years, giant cell > 50 years)
- FDG PET can determine active disease
- Aortic caliber will be reduced
- Subclavian stenosis is hallmark finding
- Pulmonary artery strictures and mesenteric vessel stenosis are common
Radiation
- Vascular calcifications confined to radiation field
- Radiation history will be present