- “Thoracic endovascular aortic repair (TEVAR) has evolved as an alternative to open repair for a range of aortic pathology. The earliest endovascular repairs were limited to descending thoracic aortic pathology, but growing experience has resulted in the use of stents in the ascending aorta and aortic arch. This review presents the current literature pertaining to thoracic endoluminal stent repair, with emphasis on the role of intravenous contrast-enhanced multidetector computed tomography, the primary cross-sectional imaging modality used in these patients. Radiologists play an integral role in patient selection, procedural planning, and postprocedural follow-up.”
Thoracic endovascular aortic repair: literature review with emphasis on the role of multidetector computed tomography
Johnson PT, Black JH, Zimmerman SL, Fishman EK
Semin Ultrasound CT MR 2012 Jun; 33(3):247-64 - “This review presents the current literature pertaining to thoracic endoluminal stent repair, with emphasis on the role of intravenous contrast-enhanced multidetector computed tomography, the primary cross-sectional imaging modality used in these patients. Radiologists play an integral role in patient selection, procedural planning, and postprocedural follow-up.”
Thoracic endovascular aortic repair: literature review with emphasis on the role of multidetector computed tomography
Johnson PT, Black JH, Zimmerman SL, Fishman EK
Semin Ultrasound CT MR 2012 Jun; 33(3):247-64
- “ MDCT with virtual angioscopy can depict the configuration of intimal tears in cases of thoracic aortic dissection, which may facilitate therapeutic planning.”
Intimal Tears in Thoracic Aortic Dissection: Appearance on MDCT With Virtual Angioscopy
Maldjiian PD eta l.
AJR 2012; 198:955-961 - “MDCT can depict feature helping to differentiate the true lumen from the false lumen. The false lumen is usually larger than the true lumen and commonly deforms the shape of the true lumen.”
Intimal Tears in Thoracic Aortic Dissection: Appearance on MDCT With Virtual Angioscopy
Maldjiian PD eta l.
AJR 2012; 198:955-961 - “Flow in the false lumen is usually slower than that in the true lumen; hence the attenuation of the false lumen tends to be lower and more heterogeneous than the attenuation of the true lumen because of mixing of contrast agent with unopacified blood.”
Intimal Tears in Thoracic Aortic Dissection: Appearance on MDCT With Virtual Angioscopy
Maldjiian PD eta l.
AJR 2012; 198:955-961 - “ Imaging of the thoracoabdominal aorta with ECG-triggered high-pitch CTA provides higher quality images of the aortic root and ascending aorta with sufficient contrast enhancement and decreased estimated radiation dose compared with non-ECG-synchronized standard pitch CT.”
Image Quality, Contrast Enhancement, and Radiation Dose of ECG-Triggered High Pitch CT Versus Non-ECG-Triggered Standard-Pitch CT of the Thoracoabdominal Aorta
Bolen MA et al.
AJR 2012;198:931-938
- “ Unenhanced CT performed well in detection of acute aortic syndrome treated surgically, although its performance does not support its use in place of contrast enhanced CTA. Unenhanced CT may be a reasonable first examination for rapid triage when IV contrast is contraindicated.”
Acute Aortic Syndromes: A Second Look at Dual-Phase CT
Lovy AJ et al.
AJR 2013; 200:805-811 - “ Contrast-enhanced CTA was highly sensitive for intramural hematoma, suggesting that unenhanced imaging may not always be needed. Acute aortic syndrome imaging protocols should be optimized to reduce radiation dose.”
Acute Aortic Syndromes: A Second Look at Dual-Phase CT
Lovy AJ et al.
AJR 2013; 200:805-811 - Acute Aortic Syndrome
- Aortic dissection
- Intramural hematoma
- Penetrating atherosclerotic ulcer
- Ruptured aortic aneurysm - “ 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 ulcer like projections.”
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) is an intramural contrast medium filled pool with a tiny intimal orifice and/or a connection with an intercostal or lumbar artery in an IMH; IBP is morphologically distinct from an ulcer like projection (ULP) which has a wiser 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 - “ Most Intramural blood pools (IBP) show complete resorption over time (32 of 56 (57%) or have incomplete 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
- Aortic Transection: Facts
- 10-20% of patients survive the initial event
- Occurs most commonly at aortic isthmus (space between brachiocephalic trunk and that of the ligamentum arteriosus)
- Mediastinal hematoma (anterior of posterior mediastinum) is common but not diagnostic of aortic injury
- Hematoma of interest most commonly around the aorta - Aortic Transection: Facts
- The direct signs of aortic transection include;
- Vessel caliber change
- Pseudoaneurysm
- Intramural flap - Cardiac Trauma: Differential Diagnosis
- Aortic transection
- Valvular rupture
- Hemopericardium
- Cardiac tamponade - “ The “panscan” (computed tomographic (CT) examination of the head, neck, chest, abdomen, and pelvis) has become an essential element in the early evaluation and decision making algorithm for hemodynamically stable patients who sustained abdominal trauma.”
Multidetector CT of Blunt Abdominal Trauma: State of the Art
Soto JA, Anderson SW
Radiology 2012;265:678-693 - “ In patients with hemoperitoneum, the presence of active extravasation and the rate of bleeding have a more direct effect on patient care decisions than does the volume of free fluid in the abdomen.”
Multidetector CT of Blunt Abdominal Trauma: State of the Art
Soto JA, Anderson SW
Radiology 2012;265:678-693 - TAA: Complications
- Rupture- risk relates directly to size
- Dissection
- Aortic regurgitation
- Compression of adjacent mediastinal structures
- Concomitant coronary artery disease - TAA: Repair
- Surgical thresholds
- 5.5 cm ascending aorta
- 6.5 cm descending aorta
- Lower thresholds in patients with genetic syndromes
- Marfans syndrome, Loeys-Dietz syndrome
- Increased risk of dissection and rupture - Genetic Syndromes: Repair
- Aortic root or ascending aorta > 5 cm OR rate of enlargement > 0.5 cm per year
- For those who need aortic valve replacement, root or ascending aorta repair if > 4.5 cm
- Smaller patients have lower thresholds
- Counsel patients considering pregnancy at size of 4.0 to 4.5 cm
- LDS patients – repair at 4.5 cm - TEVAR: Role of Radiologist
- Thoracic Endovascular Aortic Repair
- Determine patient is a candidate for TEVAR
- Perform critical pre-procedural analyses
- Location and extent of the pathology
- Requirement for branch vessel occlusion
- Risk of spinal cord ischemia
- Identify risk factors for deployment failure
- Angulation of the aorta and run-off vessels
- Provide information to guide stent selection - Ascending Aorta IMH Mgt
- Criteria for Observation
- Hemodyamically stable, no persistent pain
- Aorta - 50 mm
- Hematoma - 10 mm thick
- No penetrating atherosclerotic ulcer
- No ulcer-like projection
- Small effusions
- No aortic insufficiency - Ascending Aorta IMH Mgt
- Criteria for Observation
- Hemodyamically stable, no persistent pain
- Aorta - 50 mm
- Hematoma - 10 mm thick
- No penetrating atherosclerotic ulcer
- No ulcer-like projection
- Small effusions
- No aortic insufficiency - Ascending Aorta IMH Mgt
- Criteria for “timed” surgery
- Pain
- New ulcer-like projection
- Progression to aortic dissection
- Increasing IMH thickness
- Increasing aortic diameter
- Increasing effusion
- Tamponade - Penetrating Ulcer
- Underlying atherosclerotic disease
- Atheromatous plaques erode and penetrate internal elastic lamina
- 80% have intramural hematoma - Penetrating Ulcer
- Complications:
- Aneurysm
- Pseudoaneurysm
- Dissection
- Rupture
- Rupture risk relates to aortic size - Aortic Dissection: Causes
- Hypertension
- Collagen vascular disease
- Genetic vascular syndromes
- Marfans, Loeys-Dietz, Ehlers Danlos
- Trauma
- Iatrogenic
- Cardiac surgery
- Penetrating ulcer
- Bicuspid aortic valve - Dissection: Classification
- DeBakey
- 1: ascending aorta, arch and beyond
- 2: ascending aorta only
- 3: descending aorta only
- Stanford
- A: ascending aorta propogation
- B: no ascending aorta propogation - TAD: Complications
- Aortic rupture
- Pericardial tamponade
- End organ ischemia
- Over time, false lumen can dilate resulting aneurysm formation
- Retrograde Type A Dissection:
Risk Factors
1. Graft
- those with proximal bare springs
2. Aorta
- steeply angulated aortic arch in the setting of a morphologically normal aorta
3. Both
- compliance mismatch between the stent graft and aortic wall - Operative Aortic Repair
- Abdominal aortic graft instability
- Aortic root repair
- Extensive aortic pathology and staged repair - Post Surgical Repair
- Comparative series of 1252 patients repaired with endoluminal stents and surgical grafts followed for up to 10 years reported rupture only after endovascular treatment.
- Following surgical repair, the rate of anastomotic pseudoaneurysm formation (contained rupture) is 0.2-15% - Post Surgical Repair
1. Surgical grafts dilate over time, rates depending on the graft material (ePTFE vs polyester).
- At 6 years, dilatation ranges between 20-30%
- ePTFE exhibits lowest degree of dilatation
- Dilatation does not result in graft failure
2. Grafts lose strength over time, owing to polyester degradation.
- 31.4% lost at 10 years
- 100% lost at 25-39 years - Aortic Root Repair
1. Must know surgical procedure
- valve may be replaced
- coronary reimplantation or bypass
2. Full root interposition
- Excision and end-to-end anastomoses
3. Inclusion root technique
- Native root wrapped around graft - Complications
1. Vascular
- pseudoaneurysm
- coronary ostial aneurysm
- dissection
- endoleak
2. Periaortic
- mediastinitis
- sternal dehiscence - Extensive Aortic Pathology
1. Pathology that involves ascending aorta, aortic arch, descending aorta
- +/- abdominal aorta
2. Necessitates staged repair
3. Stage 1:
- Ascending aortic graft
- Elephant trunk prosthesis arch/proximal descending thoracic aorta
4. Stage 2:
- Descending aorta +/- abdominal aorta repair
- Ductus Aneurysm: Facts
- Most common mechanism is failure of closure of the aortic side of the ductus arteriosus
- In adults may present with cough, dyspnea, or dysphonia
- Can be confused with traumatic aneurysm of the aorta but that is usually located in the posterior part of the arch distal to the origin of the left subclavian artery
- Calcifications are not uncommon in ductus aneurysms - “Aneurysm of the ductus arteriosus is a very rare congenital lesion in adults that can be associated with thromboembolism, rupture, and death. Its detection in a silent clinical phase is very important for planning appropriate treatment and avoiding potentially fatal complications.”
Incidental detection of a giant ductus arteriosus aneurysm by low-dose multidetector computed tomography in an asymptomatic adult
Pontone G et al.
J Vasc Surg Vol 5;5 pg 1260-1264 May 2010
- Persistent Left SVC: Facts
- Represents persistence of the left common cardinal vein
-Usually drains into the coronary sinus
- Usually associated with absent left brachiocephalic vein
- Usually has SVC present as well
- Occurs in 0.2-0.4% of patients - Collateral pathways are commonly opacified in SVC Syndrome
- Azygous and hemiazygous system
- Paravertebral vessels
- Mediastinal veins as collaterals (as in this case)
- Anterior intercostal veins
- Internal mammary veins - “C” - Double aortic arch
- Rare anomaly caused by persistence (to varying degree) of the fetal double aortic arch
system.
- The ascending aorta divides into two arches that pass to either side of the esophagus and
trachea and reunite to form the descending aorta.
- Form of complete vascular ring, resulting in noncardiac morbidity, but rarely associated
with intracardiac defects.
- The descending aorta is usually on the left side.
- Most commonly, one arch is dominant, whereas the other may be of small caliber or
represented by a fibrous band - “A” - Right AA with mirror image branching
The mirror-image type of the right aortic arch (left brachiocephalic trunk, right common
carotid and subclavian arteries) is almost always associated with congenital heart disease,
especially the cyanotic type. - “B” - Right AA with aberrant left subclavian artery
-Right aortic arch is an uncommon anatomical anomaly that occurs in <0.1% of the population.
-The most common type is the right aortic arch with an aberrant left subclavian artery
-The vessels originate in the following order: left common carotid, right common carotid, right subclavian, and left subclavian artery.
-Symptoms may arise from vascular ring formation as congenital heart disease is rare in this variant. - “D” - Left AA with aberrant right subclavian artery
- The right subclavian artery is the last branch of the aortic arch in l% of individuals.
- It courses to the right behind the esophagus in 80% of these cases, between the esophagus
and trachea in 15%, and anterior to the trachea or mainstem bronchus in 5%.
- A retroesophageal course may be the cause of so-called dysphagia lusoria.
- Another variant - aberrant right brachiocephalic artery is rare - Classification:
- Double aortic arch
- Right arch dominant
- Left arch dominant
- Balanced arches
- Right aortic arch–left ligamentum
- Mirror-image branching
- Retroesophageal left subclavian artery
- Circumflex aorta
- Pulmonary artery sling - Vascular Ring Hierarchy
- If abnormal combination of derivatives of the aortic arch system results in encirclement of
the trachea and the esophagus it is often referred to as “vascular ring”.
- International Congeital Heart Surgery Nomenclature And Database Committee - Normal Anatomy
- Predominant human anatomy is a left aortic arch with three great vessels; first, the
brachiocephalic trunk, then the left common carotid artery and finally the subclavian artery.
This pattern occurs in 65-80% of the cases.
- A common brachiocephalic trunk, so-called “bovine trunk”, in which both common carotid
arteries and the right subclavian artery arise from a single trunk off the arch, occurs in 10 to
22% of individuals and accounts for more than two thirds of all arch vessel anomalies. - Abdominal Aorta Prestent
-Need 1.0-1.5 cm distance between proximal landing zone and renal aa
-Infrarenal neck
-Neck angulation - Thoracic Aorta Prestent
-Need at least 1 cm normal aortic wall between landing zone and major branch
-Diameter of proximal and distal aortic necks
-Diameter of femoral and iliac arteries - Stent Planning
-Describe aneurysm
-Size both diameter and length
-Location
-Distance of aneurysm from branch vessels
Impediments to stent placement
-Femoral or iliac a small caliber or stenoses
-Severe aortoiliac tortuousity - Aortic Surgery
-First successful surgical repair was in 1951 using a cadaver graft
-Prior to this, techniques included cellophane wrapping and ligation - Aortic Repair
-Surgical endograft
-Surgical bypass graft
-Endoluminal stent placement - Aortic Dissection:
Complications
-Aortic rupture
-Pericardial tamponade
-End organ ischemia
-Over time, false lumen can dilate resulting in aneurysm formation - Aortic Dissection: Classification
DeBakey
-1: ascending aorta, arch and beyond
-2: ascending aorta only
-3: descending aorta only
Stanford
-A: ascending aorta propogation
-B: no ascending aorta propogation - Aortic Dissection Causes
-Aneurysm
-Hypertension
-Trauma
-Iatrogenic
-Collagen vascular disease
-Cardiac surgery
-Penetrating ulcer
-Bicuspid or replaced aortic valve - Penetrating Ulcer
Complications:
-Aneurysm
-Pseudoaneurysm
-Dissection
-Rupture
Rupture risk relates to aortic size - Penetrating Ulcer
-Underlying atherosclerotic disease
-Atheromatous plaques erode and penetrate internal elastic lamina
-80% have intramural hematoma - F/U Intramural Hematoma
Generally decrease in size or resolve
May progress to other aortic pathology
-Fusiform aortic aneurysm
-Dissection
-Development of ulcer-like projections - Ascending Thoracic Aorta Intramural Hematoma Mgt
Criteria for Observation
-Hemodyamically stable
-No persistent pain
-Aorta less than or equal to 50 mm
-Hematoma less than or equal to 10 mm thick
-No PAU or ULP
-Small effusions
-No aortic insufficiency
Criteria for “timed” surgery
-Pain
-New ULP
-Progression to AD
-Increasing IMH thickness
-Increasing aortic diameter
-Increasing effusion
-Tamponade
-No regression - Intramural Hematoma
-Management varies according to location (ascending vs descending aorta)
-Many advocate surgery for ascending aortic involvement or “timely surgery” - Thoracic Aortic Pseudoaneurysm
-Sequela of cardiac surgery
-Ascending aorta most common location
-Arise from surgically manipulated locations
--proximal valve graft anastomosis
--distal aortic anastomosis
--coronary button reimplantation
--vein graft anastomosis - Draped Aorta Sign
Contained rupture
Posterior wall of aorta
-not identifiable as distinct from adjacent structures
-closely follows the contour of adjacent vertebral bodies - Aneurysm Instability
Impending rupture
- Crescent sign
Contained rupture
- Draped aorta sign - Aneurysm Growth Rate
Mean expansion rate is 2.6 -3.6 mm/yr
- Most grow 1-4 mm/year
- Growth rate directly correlates with size
Aneurysms that enlarge rapidly are at risk for rupture - Abdominal Aortic Aneurysm
- Larger than 3 cm
- 4 - 5.4 cm can be monitored
- Fusiform > 5.4 cm warrants repair - TAA: Complications
- Rupture- risk relates directly to size
- 5.5 cm as surgical threshold for ascending
- 6.5 cm as surgical threshold for descending
- Dissection
- Aortic regurgitation
- Compression of adjacent mediastinal structures
- Concomitant coronary artery disease - Aortic Measurements
Midascending aorta: < 4 cm
Descending aorta: < 3 cm
Abdominal aorta:
- < 3 cm proximally
- Tapers to 2.5 cm distally
Enlarges normally with age
Slight difference between systole & diastole (< 2 mm)
"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 - Aortic Arch Vessel Mapping
"Given the widespread availability as well as the ease of acquiring CTA in the trauma setting, CTA is increasingly being used as the initial diagnostic evaluation in extremity vascular trauma, replacing digital subtraction angiography in many institutions." Extremity CT Angiography: Application to trauma using 64-MDCT
Sah N et al.
Emerg Radiol (2009) 16;425-432 - Aortic Arch Vessel Mapping
"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 - Vascular: 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) - 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
- 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 "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 - Takayasu Arteritis: Numano Classification
- Type I: involvement of only the branches of the aortic arch
- Type IIA: involvement of the ascending aorta or the aortic arch with or without branches
- Type IIB: involvement of the descending thoracic aorta with or without the ascending aorta or the aortic arch with its branches
- Type III: involvement of the entire descending aorta with or without the renal arteries
- Type IV: involvement of only the abdominal aorta with or without the renal arteries
- Type V: involvement of the entire aorta with branches Involvement of the coronary arteries or the pulmonary arteries is indicated with a C(+) or P(+) respectively - Takayasu Arteritis: Facts
- Large vessel arteritis that affects aorta and its branches
- Affects woman and young girls most commonly (80-90% are female in second and third decade of life)
- Circumferential wall thickening is earliest finding
- Treatment includes steroids or immunosuppressive therapy as well as surgical revascularization of sites of involvement - Marfans Syndrome: Surgery
- Ascending aorta 45 mm or growing greater than 0.5 cm/yr is indication for surgery
- Repair is of root , aortic valve and ascending aorta - Marfans Syndrome: Cardiovascular Findings
Minor Criteria
- Dilatation or dissection of the descending or abdominal aorta before the age of 50 years
- Dilatation of the main pulmonary artery before age 40
- Mitral valve prolapse
- Calcification of the mitral valve before age 40 - Marfans Syndrome: Cardiovascular Findings
Major Criteria
- Dilatation of the ascending aorta involving at least the sinuses of Valsalva with or without aortic regurgitation
- Dissection of the ascending aorta - Ghent Criteria: Major and Minor Findings
- 2 major and 1 minor criteria
or
- 1 major and 4 minor criteria
- Marfan Syndrome: Facts
- Autosomal dominant
- Caused by mutations in the fibrillin-1 gene (FBN1) on chromosome 15
- Diagnosis based on Ghent criteria which include cardiovascular, ocular, and pulmonary abnormalities
- Average age of death in untreated patients is 35 years while in treated patients up to age 75 years - Supravalvular Aortic Stenosis: facts
- Focal or diffuse narrowing of the aorta starting at the sinotubular junction and often involves the entire ascending aorta
- SVAS may be associated with Williams-Beuren syndrome which is an autosomal dominant multisystematic disorder that may manifest with SVAS (71% of cases), mitral valve prolapse and pulmonary artery stenosis - Coarctation of the Aorta: Facts
- Male predominance (1.5:1)
- Aortic narrowing in region of ligamentum arteriosum just distal to the left subclavian artery
- Solitary lesion in 82% of cases but can be associated with Turner syndrome, bicuspid aortic valve, intracranial aneurysms, VSD and ASD defects, and Shone complex (left ventricular outflow tract obstruction and parachute mitral valve) - Acute Aortic Syndrome Includes;
- Penetrating atherosclerotic ulcer
- Acute thoracic aortic injury
- Intramural hematoma
- Dissection
- Aneurysmal leakage
- Thoracic Endovascular Stents: Endoleaks
- Type I: these result from incomplete seal of the ends of the stent to the aortic wall
- Type II: result from retrograde flow of blood into excluded lumen from patent branch vessels of the aorta
- Type III: result from junctional dehiscence or device degeneration
- Type IV: result from porosity of the stent
- Type V: are increase in size of excluded lumen w/o enhancement in excluded lumen
- Thoracic Endovascular Stents: Endoleaks
- Occur in up to 29% of cases
- Five types of endoleaks occur
- Type I account for 40% of all endoleaks
- Thoracic Endovascular Stents: Complications
- Collapse of stent
- Migration of stent
- Endoleak
- Pseudoaneurysm or dissection
- Pulmonary embolism
- Thoracic Endovascular Stents:Indications
- Aortic aneurysms
- Acute and chronic dissection
- Penetrating ulcer
- Intramural hematoma
- Traumatic aortic rupture
- Complications of Endovascular Stent Placement
- Endoleaks
- Stent migration
- Pseudoaneurysms
- Dissection
- Aortic perforation
- Kinking
- Thrombosis
- Coverage of key arch vessels
"Postprocedure multidetector CT is mandatory to assess stent placement, efficacy, and complications. Important factors to document are location of the stent, stent patency, size of the aorta, thrombosis of disease outside the aortic lumen, and any complications."
Thoracic Aortic Stent-Grafts: Utility of Multidetector CT for Pre- and Postprocedure Evaluation
Bean MJ, Johnson PT, Roseborough GS, Black JH, Fishman EK
RadioGraphics2008; 28:1835-1851
"In this article, we discuss which patients are potential candidates for thoracic aortic stent graft placement and demonstrate how multidetector computed tomography with two dimensional multiplanar reformation (MPR) and three dimensional rendering (3D) is relevant in preoperative imaging and post operative assessment of thoracic stent grafts."
Thoracic Aortic Stent-Grafts: Utility of Multidetector CT for Pre- and Postprocedure Evaluation
Bean MJ, Johnson PT, Roseborough GS, Black JH, Fishman EK
RadioGraphics2008; 28:1835-1851
- Thoracic Endovascular Stent Placement: Patient Selection
- Penetrating ulcers
- Aortic aneurysm
- Aortic dissection
- Acute traumatic aortic injury
- Aortic coarctation
- Thoracic Aneurysm Repair in Elderly Patients: Complications
- Mortality rate is 7-12% in elective cases
- Mortality is up to 40% in elective cases
- CTA and Thoracic Stent Grafts
- Pre-operative planning
- Post-operative assessment
- Endoleak Graft movement or fracture
- Size of native aorta
"Potential complications of endovascular stent placement include endoleaks, stent migration, pseudoaneurysms, dissection, aortic perforation, kinking, thrombosis, and coverage of vital branch vessels." Thoracic Aortic Stent-Grafts: Utility of Multidetector CT for Pre- and Postprocedure Evaluation Bean MJ, Johnson PT, Roseborough GS, Black JH, Fishman EK RadioGraphics 2008; 28:1835-1851
- Endovascular Stent Placement: Applications
- Penetrating ulcers
- Aortic dissection
- Aortic aneurysms
- Aortic rupture
- Congenital abnormalities
- Endovascular Stent Placement: Complications
- Endoleaks
- Stent migration
- Pseudoaneurysms
- Dissection
- Aortic perforation
- Kinking
- Thrombosis
- Coverage of vital branch vessels
- "End diastolic diameter 95% confidence levels were 2.5-3.7 cm for the aortic root, 2.1-3.5 cm for the ascending aorta, and 1.7-2.6 cm for the descending thoracic aorta. Aortic diameters were significantly greater at end systole than end diastole (mean difference 1.9 ± 1.2 mmfor ascending aorta and 1.3 ± 1.8 for descending thoracic aorta. P < 0.001)"
- "End diastolic diameter 95% confidence levels were 2.5-3.7 cm for the aortic root, 2.1-3.5 cm for the ascending aorta, and 1.7-2.6 cm for the descending thoracic aorta. Aortic diameters were significantly greater at end systole than end diastole (mean difference 1.9 ± 1.2 mmfor ascending aorta and 1.3 ± 1.8 for descending thoracic aorta. P < 0.001)"
Assessment of the thoracic aorta by multidetector computed tomography: Age and sex specific reference values in adults without evident cardiovascular disease
Lin FY et al.
J Cardiovasc Comput Tomogr (2008) 2, 298-308
- "Aortic diameters were significantly greater at end systole than end diastole (mean difference 1.9 ± 1.2 mmfor ascending aorta and 1.3 ± 1.8 for descending thoracic aorta. P < 0.001)."
Assessment of the thoracic aorta by multidetector computed tomography: Age and sex specific reference values in adults without evident cardiovascular disease
Lin FY et al.
J Cardiovasc Comput Tomogr (2008) 2, 298-308
- Patent Ductus Arteriosus (PDA): Facts
- Isolated Patent Ductus Arteriosus accounts for up to 10-12% of all congenital heart anomalies
- Most incidentally discovered PDAs in adult are asymptomatic
- Diagnosis on CT is based on defining a vessel connecting the main pulmonary artery and the aorta that is patent
- Patent Ductus Arteriosus (PDA): CT Findings
- Calcification at the site of the PDA is common
- Communication best seen on MPR and 3D images
- Flow may be from aorta to pulmonary artery or pulmonary artery to aorta
- Aortic Root Imaging: Facts
- Diameter of aortic root is less than or equal to 3.9 cm
- Diameter of ascending aorta is less than or equal to 3.5 cm at level of right pulmonary artery
- Diameter of normal aortic arch is less than or equal to 3.0 cm
- Diameter of normal descending aorta is less than or equal to 2.5 cm
- Aortic Root Aneurysms: Associated Syndromes
- Marfans syndrome
- Loeys Dietz syndrome
- Ehlers Danlos syndrome
- Bicuspid aortic valve
- Familial thoracic aortic aneurysm syndrome
- "Loeys-Dietz Syndrome manifests with aggressive vascular pathology. Aneurysms may form at a young age and have a propensity for arterial dissection. In addition, aneurysms rupture at diameters smaller than those used to dictate surgical intervention for other syndromes and disorders".
Loeys-Dietz Syndrome: MDCT Angiography Findings Johnson PT, Chen JK, Loeys BL, Dietz HC, Fishman EK AJR 2007;189; 226
- Coarctation of the Aorta:Facts
- Narrowing of aortic lumen results in LV hypertrophy
- Collaterals and rib notching are common
- May be isolated finding or associated with other cardiac issues
- Coarctation of the Aorta:Facts
Associated with cardiac anomalies
- Bicuspid valve (50%)
- VSD (33%)
- PDA (66%)
- Subaortic and mitral stenosis
- Coarctation of the Aorta: Facts
- 20-30% of Turners syndrome patients have a COA
- Males > females by 2-1
- "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 rupture
- 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
- CT of the Thoracic Aorta: Causes of Study Failures
- Injection technique faulty (too slow,contrast extravasation, etc.)
- Poor scan timing (data acquisition to contrast delivery)
- Patient motion during study
- CT of the Thoracic Aorta: Pitfalls
- Artifacts off venous structures tend to be worse for left sided injections and create problems with the arch vessels as well as the ascending aorta
- Possible solutions: saline chaser, caudal-cranial scanning
- CT of the Thoracic Aorta: Pitfalls
- Aortic pulsation is an issue in the aortic root and ascending aorta and can result in false positive studies
- Possible solutions: faster scanners (4-16-64), cardiac gating, partial scan data reconstruction (half scan reconstruction)
- MDCT vs. MR vs. TEE
- Alternative diagnosis best defined on CT study
- Pulmonary embolism
- Mediastinal mass
- Coronary artery occlusion
- Intramural Hematoma: MDCT Findings
- High CT attenuation on non contrast CT scans
- Focal ulcer usually present
- More common in descending aorta but occurs in ascending aorta as well
- Congenital Anomalies of the Thoracic Aorta
- Sequestration
- Vascular rings
- Coarctation of the aorta
- Abberrant vessels
- Right sided arch and associated anomalies
- "The optimal reconstruction phase varied between patients, and this was directly related to the heart rate."
Thoracic Aorta at Multidetector Row CT: Motion Artifact with Various Reconstruction Windows
Morgan-Hughes GJ et al.
Radiology 2003; 228:583-588
- Aortic Stenosis: Etiology
- Coarctation or pseudocoarctation
- Midaortic dysplastic syndrome
- Atherosclerosis
- Takayasu arteritis
- Aortic dissection
- Retroperitoneal fibrosis
- S/P surgical repair
- True vs False Aneurysm
- True Aneurysm-thinning and stretching of the vessel wall due to weakening of its structural integrity
- False or pseudoaneurysm- extravascular hematoma that communicates with a vessel and is contained by a fibrous capsule
- Pseudoaneurysms: Etiology
- Trauma
- Iatrogenic
- Infection
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