"Most IBPs show complete resorption over time (32 of 56 957%) or have incmplete resorption (16 of 56 (29%) during a median follow-up of 33.8 months: the presence of IBP was not associated with poor prognosis." Intramural Blood Pools Accompanying Aortic Intramural hematoma: CT Appearance and Natural Course
Wu MT et al.
Radiology 2011;258:705-713 "IBP is an intramural contrast medium filled pool with a tiny intimal orifice and/or a connection with an intercostal or lumbar artery in a IMH: IBP is morphologically distinct from an ulcerlike projection (ULP) which has a wider intimal opening to the lumen." Intramural Blood Pools Accompanying Aortic Intramural hematoma: CT Appearance and Natural Course
Wu MT et al.
Radiology 2011;258:705-713 "In patients with aortic IMH, IBP is not an uncommom finding: IBP is associated with a relatively benign clinical course that shows complete resorption or stability in most patients (86%)." Intramural Blood Pools Accompanying Aortic Intramural hematoma: CT Appearance and Natural Course
Wu MT et al.
Radiology 2011;258:705-713
" Intramural blood pools (IBP) are frequently observed at multidetector CT in patients with intramural hematoma (IMH). They may resolve over time or appear during follow-up. These findings are not associated with a poor prognosis, and IBPs should be distinguished from ulcerlike projections." Intramural Blood Pools Accompanying Aortic Intramural hematoma: CT Appearance and Natural Course
Wu MT et al.
Radiology 2011;258:705-713 "A total of 65.9% of patients had both normal aortic arch branching patterns and normal venous anatomy. Variants in the aortic arch branching pattern were present in 32.4% and anomalies in 1.5%. Venous anomalies were present in 0.7%." Variants and Anomalies of Thoracic Vasculature on Computed Tomographic Angiography in Adults
Berko NS et al.
J Comput Assist Tomogr 2009;33: 523-528 - Aortic Arch Vessel Mapping
- Normal arch branching seen in 65% of cases ( separate origins of brachiocephalic, left common carotid, left subclavian)
- Bovine arch branching is seen in 27% of cases (common origin of brachiocephalic and left carotid artery)
- Other variations are seen in 8% of cases and include left vertebral artery off the arch, right aortic arch, aberrant right subclavian artery)
- Maximum Aortic Diameter
| Segment | Size | | Ascending | 4 | | Descending | 3 | | Abdominal | 2 |
- Aortic Arch Anatomy: Variations
- 3 branches; right innominate, left carotid, left subclavian (70% of patients)
- 2 branches; right innominate and left subclavian arise from a common trunk, left suclavian (30%)
- Left vertebral aa arises off arch between left carotid and left subclavian (5%) - Stanford Type B Dissection
- Involves the descending aorta distal to the left subclavian artery
- Accounts for 30-40% of cases
- Usually managed conservatively
- Surgery required including ruptured aorta, aneurysm over 6 cm, poor perfusion of mesenteric vessels or renal arteries, distal embolization -
- Stanford Type A Dissection
- Involves ascending aorta and may extend into the descending aorta
- Account for 60-70% of cases
- Requires surgical intervention
- Mortality rate of up to 50% at 48 hours if untreated "Multidetector CT allows the early recognition and characterization of aortic dissection as well as determination of the presence of any associated complications, findings that are essential for optimizing treatment and improving clinical outcomes." Multidetector CT of Aortic Dissection: A Pictorial Review
McMahon MA, Squirrell CA
RadioGraphics 2010; 30:445-460 - Why do we gate evaluation of the thoracic aorta?
- Quality evaluation of the entire thoracic aorta including the aortic sinus and aortic valve
- Definition of the coronary arteries especially in the proximal portions of the coronaary vessels "Optimal image quality for either technique is obtained with a relatively slow heart rate, which may require beta-blocker medication." Prospective and Retrospective ECG Gating for Thoracic CT Angiography: A Comparitive Study
Wu W et al.
AJR 2009;193:955-963 "Compared with retrospective ECG-gated thoracic CT angiography, prospective ECG-gated thoracic CT angiography was associated with a lower radiation dose, slightly increased contrast load, increased aortic attenuation values, and equivalent image quality." Prospective and Retrospective ECG Gating for Thoracic CT Angiography: A Comparitive Study
Wu W et al.
AJR 2009;193:955-963 - When do you electively operate on thoracic aortic aneuysms?
- Ascending aorta exceeding 5.5 cm
- Descending aorta exceeding 6.5 cm
- Increase in aneurysm size of greater than 1 cm in one year
- Dilated Sinus of Valsalva: Differential Dx
- Marfan’s syndrome (most common)
- Homocystinuria
- Ehlers-Danlos syndrome
- Osteogenic imperfecta
- Idiopathic
"Although the aortic diameter increases slightly with age, the normal diameter of the midascending aorta should always be less than 4 cm, and that of the descending aorta no more than 3 cm."
Multidetector CT of Thoracic Aortic Aneurysms
Agarwal PP,Chughtai A, Matzinger FRK, Kazerooni EA
RadioGraphics 2009; 29:537-552
"Multidetector CT angiography is routinely used to evaluate the spectrum of thoracic aortic aneurysms. Knowledge of the causes, significance, imaging appearances, and potential complications of both common and uncommon aortic aneurysms is essential for prompt and accurate diagnosis."
Multidetector CT of Thoracic Aortic Aneurysms
Agarwal PP,Chughtai A, Matzinger FRK, Kazerooni EA
RadioGraphics 2009; 29:537-552
"Aortic valve area on CT strongly correlates with echocardiography and has excellent sensitivity and specificity to detect severe stenosis." Aortic Valve Area on 64-MDCT Correlates with Transesophageal Echocardiography in Aortic Stenosis LaBounty TM et al. AJR 2008; 191:1652-1658 "Aortic valve area on CT strongly correlates with echocardiography and has excellent sensitivity and specificity to detect severe stenosis. Valve calcification has fair agreement between studies. Valve area and calcification should be reported on CT Angiography in patients with AS." Aortic Valve Area on 64-MDCT Correlates with Transesophageal Echocardiography in Aortic Stenosis LaBounty TM et al. AJR 2008; 191:1652-1658 - "Endovascular stent graft repair is less invasive in patients with chronic and acute descending thoracic aortic aneurysm and dissection."
Descending Thoracic Aortic Diseases: Stent-Graft Repair Fattori R et al.
Radiology 2003; 229:176-183 - Stent-Graft Placement in the Thoracic Aorta: Indications
- Descending thoracic aneurysms
- Dissection of descending aorta
- Ulcers in descending aorta
- Repair mycotic aneurysm
- Post-traumatic aortic ruptur - "Multidetector row CT allows reliable assessment of anatomic relationships between the lesion and the aortic branches as well as evaluation of the iliac and femoral arteries (diameter,tortuosity) for vascular access."
Stent-Graft Placement for the Treatment of Thoracic Aortic Disease
Therasse E et al.
RadioGraphicss 2005; 25:157-173 - Thoracic Aorta: Pitfalls in CT Scanning
- False positive dissection due to motion (cardiac and/or respiratory) or streak artifact of SVC
- Aortic root
- Ascending aorta
- Aortic arch - CT of the Thoracic Aorta: Clinical Applications
- Suspected aneurysm or dissection
- Thoracic trauma
- Vasculitis
- Congenital disease (i.e. COA)
- Pre-operative stent planning
- Follow up of stent placement - Scanning Parameters
Scanner type 16 slice MDCT 64 slice MDCT
kVp 120 120
mAs 150-180 130-180
Scan collimati on .75 mm .6
Slice thickness .75 mm .75
Interscan spacing .5 mm .5
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