Thoracic aorta Flashcards
Tubular candy cane shaped structure that connects the left ventricle to systemic circulation
Thoracic aorta
Thoracic aorta extends from what level down to what level before it becomes the abdominal aorta
Aortic valve to diaphragmatic hiatus
Thoracic aorta us divided into
Aortic root, ascending aorta, transverse arch, and descending aorta
Extends from the aortic annular ring to the sinotubular junction
Aortic root
Fibrous oval ring where the leaflets of the aortic valve attach and extend superiorly toward the sinuses of valsalva
Aortic valve annulus
Coupled to the mitral annulus via aortomitral fibrous tissue, which is a defining feature of the left ventricle
Aortic annulus
Pulmonary valve is supported by the
muscular right ventricular outflow tract
Superior to the annulus which are 3 anatomic bulges of aorta
Sinuses of valsalva
Arise from the sinuses of valsalva above the valve plane but below the sinotubular junction
Coronary artery ostia
Arise from the right sinus of valsalva which is directed anteriorly
Right coronary artery
Arises from the leftward facing left sinus of valsalva
Left coronary artery
Usually directed posteriorly between the right and left atria
Noncoronary sinus
Above the sinuses of valsalva is the ______, which is an anatomic waist between the sinuses of valsalva and tubular ascending aorta
Sinotubular junction
Aorta is generally largest in diameter at the
Sinuses of valsalva
Normal diameter of aortic root is
3.5 to 3.72 cm in females and 3.63 to 3.91 in males
Serves as both a physical and hemodynamic boundary between the left ventricle and aorta
Aortic valve
Normal aortic valve is composed of how many leaflets/cusps
3
Contact points between valve leaflets are termed
Valve commissures
Valve commissures are best visualized during
End diastole when aortic valve is closed
Most common congenital cardiovascular anomaly with a prevalence of 0.5 to 2 %
Bicuspid aortic valve
Congenital anomalies of aortic valve
unicuspid, bicuspid or quadricuspid valve
2 morphologic types of bicuspid aortic valve
True bicuspid valve and one with fused raphe
Common morphologic type of bicuspid valve
With fused raphe
With a raphe bicuspid aortic valve, fusion between what coronary cusp is the most common
Right and left coronary cusp
common complication in patients with a bicuspid aortic valve secondary to myxoid degeneration
aortic stenosis
aortopath, aneurysm formation and coarctation are also associated with
bicuspid aortic valve
repair or aortic aneurysms are recommended when they measure between
4.5 to 5 cm
the single opening in unicuspid aortic valve is usually in what side
left
type of aortic valve with cloverleaf morphology, is extremely rare and more typically associated with early onset regurgitation
quadricuspid aortic valve
ascending aorta extends from
sinotubular junction to the origin of the right brachiocephalic artery
normal ascending aorta arises where
posterior and to the right of the MPA
CT or MR evaluation of the aortic root and ascending aorta should use ____ to minimize cardiac motion artifact
ECG gating
evaluation of valvular function or dysfunction requires wht gating technique
retrospective
basic anatomic evaluation will require what gating technique
prospective
transverse segment from which the great vessels arise
aortic arch
normal aortic arch is ___sided and courses where
left-sided, courses above the pulmonary arteries
first vessel to branch from the aorta is
right brachiocephalic or innominate artery
second and third vessels to branch from the aortic arch
left common carotid artery and left subclavian artery
vertebral arteries normally arise from the
proximal aspect of the subclavian arteries
narrowing of the subclavian arteries proximal to the origin of the VA, whether degenerative, inflammatory or iatrogenic can result in _____ if there is hemodynamically significant obstruction
subclavian steal syndrome
physiologic narrowing of the aortic arch between the left subclavian artery origin and ligamentum arteriosum, the embryologic remnant of ductus arteriosus
aortic isthmus
focal prominence of aorta at the ligamentum arteriosum is a normal variant termed, _____ which should not be confused for an aneurysm or pseudoaneurysm
ductus diverticulum or ductus bump
aorta continues to become the descending aorta at what level
distal to ligamentum arteriosum
characterized by common origin of the the right brachiocephalic and left common carotid arteries; often termed as the bovine arch
two-vessel aortic arch
a true bovine arch has
only single vessel from the aortic arch
left arch variants in which the left vertebral artery has an independent origin from the aortic arch
four-vessel arch
in four-vessel arch, left vertebral artery originates between
left common carotid artery and subclavian arteries
left arch variant in which instead of the normal origin from the right brachiocephalic artery, the right subclavian artery arises distal to the left subclavian artery from the distal aortic arch and travels through the mediastinum behind the esophagus to supply the right upper extremity
left aortic arch with aberrant right subclavian artery
the aberrant right subclavian artery is associated with an aneurysm, at its origin, termed
diverticulum of Kommerell
it is an embryologic remnant of the dorsal aortic arch and can cause compressive symptoms on the esophagus if large
diverticulum of Kommerell
dysphagia secondary to extrinsic compression of the esophagus from aberrant right subclavian artery with diverticulum of Kommerell and vascular ring
dysphagia lusoria
right aortic arch can have variable arch branching patterns but the most common are
aberrant left subclavian artery and mirror-image branching
in right arch with aberrant left subclavian artery, the first branch from the aortic arch is the
left common carotid artery, followed by right carotid artery, right subclavian artery, and the aberrant left subclavian artery
the aberrant left subclavian artery passes where, in relation to the esophagus, and often with an associated diverticulum of Kommerell
posterior
aberrant left subclavian artery is also commonly accompanied by _______ which forms a vascular ring that can cause symptoms due to compression. However, it is not usually visualized on imaging
ligamentum arteriosum
in right aortic arch with mirror-image branching, the first branch is the
left brachiocephalic artery which divides into the left common carotid and subclavian arteries, followed by the right common carotid artery and right subclavian artery
true or false: if there is an aberrant subclavian artery, there cannot be mirror-image branching
true
congenital heart disease that is commonly seen with right arch and mirror-image branching
TOF
Two most common vascular rings
right aortic arch with aberrant left subclavian artery and double aortic arch
results from persistence of both right and left embryologic aortic arches. the common carotid and subclavian arteries arise from their ipsilateral arch, resulting in a four-vessel branching pattern
double aortic arch
presents as bilateral indentations on the lower trachea on frontal projection radiograph
double aortic arch
on CT or MR images, it presents as symmetric, four vessel branching at the thoracic inlet, in contrast to right or left variants, which results in asymmetric vessel branching
double aortic arch
in double aortic arch, what side of the arch is typically hypoplastic and is located inferior to the dominant arch
left arch
true or false: double aortic arch is uncommonly associated with congenital heart disease
true
high location of the aortic arch above the level of the clavicle
cervical aortic arch
discontinuity of the aortic arch in which there is complete absence or a fibrous remnant of the interrupted segment
interrupted aortic arch
type of interrupted aortic arch that occurs distal to the left subclavian take off at the isthmus
type A
type of interrupted aortic arch that occurs between the left common carotid and subclavian origins
type B
type of interrupted aortic arch that occurs between the right brachiocephalic and left common carotid origins
type C
most common type of interrupted aortic arch
type B
type of the interrupted aortic arch that is associated with VSD, bicuspid aortic valve and left ventricular outflow tract anomalies
type B
all types of interrupted aortic arch requires ____ for survival
patent ductus arteriosus
can occur with either a left or right-sided aortic arch; the arch travels posteriorly as usual but crosses the midline behind the esophagus, above the tracheal carina at the level of the distal arch/descending thoracic aorta and continues distally contralateral to the aortic arch side
circumflex aorta
descending thoracic aorta begins where
after the ligamentum arteriosum and transitions to the abdominal aorta after passing through the diaphragmatic hiatus
gives rise to multiple systemic vessels, including intercostal and bronchial arteries
descending thoracic aorta
defined as focal narrowing of the aorta adjacent to the ductus arteriosus and often occurs with varying degrees of aortic arch hypoplasia
aortic coarctation
aortic coarctation has strong associated with
bicuspid aortic valve and Turner syndrome
etiology of aortic coarctation remains unclear, but a common pathogenesis with bicuspid aortic valve has been proposed including
abnormalities of neural crest tissue migration, decreased in utero blood flow and aortopathy with cystic medial necrosis
two main types of aortic coarctation
preductal and postductal
type of aortic coarctation that tends to be more severe, involving a longer segment. commonly presents in infancy, with systemic hypoperfusion following closure of the ductus arteriosus
preductal
type of aortic coarctation that usually presents in adulthood with hypertension and signs of left heart failure
postductal
to bypass the area of aortic narrowing in aortic coarctation, collateral systemic blood flow occurs via
adjacent internal mammary and intercostal arteries which become enlarged
differential blood pressure and asymmetric pulses between right and left upper extremities is seen in what type of coarctation
preductal
differential blood pressure between upper and lower extremities is seen in what type of aortic coarctation
postductal
true or false: radiographic findings of aortic coarctation may only be apparent in severe cases
true
indentation of the distal aortic arch with pre- and postenotic dilation results in a _____ sign on chest radiograph
“figure-of-3”
ribs involved in hypertrophied intercostal arteries causing bilateral central rib notching
4th to 8th posterior ribs
surgical intervention for aortic coarctation is recommended when the coarctation pressure gradient exceeds __ mmHg
20 mmHg
congenital elongation with prominent kinking of the aorta at the aortic isthmus can mimic the appearance of coarctation and is termed
pseudocoarctation
pseudocoarctation lacks the hemodynamic changes of true coarctation, such as a significant pressure gradient and arterial collateral formation. although usually asymptomatic, pseudocoarctation is associated with
hypertension, aortic aneurysm and bicuspid aortic valve
cyclical process that starts with lipoprotein phagocytosis by macrophages, which are then incorporated into the subintima of the aortic wall. intracellular processes within the macrophage lead to formation of “foam cells”. Eventually, the marophages die, with a resultant influx of additional white blood cells and fibroblasts. the result of this cycle is an intramural mass consisting of the inner extracellular lipid core with an outer layer of inflammatory cells and connective tissue that can narrow the arterial lumen
atheroma formation
similar to coronary plaques, noncalcified or mixed plaques with a thin fibrous cap and a large necrotic core are more likely to rupture and are termed
vulnerable plaques
in some patients with severe atherosclerotic disease, thih layers of diffuse, predominantly noncalcified atherosclerotic plaques can layer much of the thoracic and abdominal aortia which has been termed
complex atheroma
this is an indirect sign of previous plaque rupture, and are independent risk factors for the development of future ischemic events and should be mentioned as they may change medical or surgical management
complex atheroma
sign of intimal disruption and lies in the “acute aortic syndrome” spectrum
penetrating atherosclerotic ulcer
congenital aneurysms of the sinuses of valsalva are also associated with what conditions
bicuspid aortic valve and VSD
acquired sinus of Valsalva aneurysms often represent pseudoaneurysms and result from
bacterial aortic valve endocarditis or aortic surgery
rupture associated with sinus of valsalva aneurysms can occur into a cardiac structure, most commonly in the
RV and RA
aortic enlargement to greater than 4 cm with preservation of vessel wall integrity — that is, without intimal disruption– may occur anywhere along the vessle
thoracic aortic aneurysm
50% of thoracic aortic aneurysms happens in
ascending aorta (proximal to the right brachiocephalic artery)
thoracic aortic aneurysms has highest association with
atherosclerosis
Homocystinuria, Marfan syndrome and other connective tissue disorders may result in dilation of the aortic annulus and proximal ascending aorta termed
annuloaortic ectasia
noninfection conditions that may result in ascending aortic aneurysms
giant cell arteritis, rheumatic fever and relapsing polychondritis
this noninfective condition may result in aneuryms involving the ascending aort, aortic arch, arch vessels, abdominal aorta and/or pulmonary arteries
Takayasu arteritis
infective aortitis may arise in the setting of bacterial endocarditis, with resultant aneurysm formation most often in the
proximal ascending aorta
more common infectious cause of ascending aortitis and aneurysm
syphillis
may lead to mycotic aneurysm
streptococcus and staphylococcus species
true or false: ascending aortic contour may be exaggerated if the patient is rotated to the right and this should not be confused for an aneurysm
true
ascending thoracic aneurysm diameter greater than ___ cm and/or interval growth greater than __ cm in 6 months or ___ cm in 1 year are indication for intervention, either surgical or endovascular
5.5 cm diameter, increase of greater than 0.5 cm in 6 months or 1 cm in 1 year
in the setting of connective tissue disease such as Marfan syndrome in patients with ascending aorta aneurysm, there is a lower threshold for repair, usually greater than ___ cm
5 cm
indications for open surgical or endovascular treatment of descending thoracic aortic aneurysm
size greater than 6.5 cm and/or interval growth (greater than 0.5 cm in 6 months or 1 cm in 1 year)
acute aortic syndrome includes ____ which share the common classical clinical presentation of excruciating chest pain that may radiate to the back
aortic dissection, acute intramural hematoma, and PAU
thoracic dissections Stanford type: involve the ascending aorta (proximal to the innominate artery) and require immediate surgical management with stent-graft placement
type A
thoracic dissections Stanford type: involve only the descending aorta (distal to th left subclavian artery)
type B
Standford type B dissections are often managed
medically, unless there is evidence of end-organ ischemia or impending rupture, in which case surgial or endovascular stent grafting is indicated
pathogenesis of aortic dissection
degeneration of aortic media, a dynamic structure that plays a vital role in regulating aortic compliance among other functions
dissections involving the ascending aorta may be complicated by
severe aortic regurgitation, cardiac tamponade due to hemopericardium, and/or coronary artery occlusion depending on propagation
diagnostic modality for aortic regurgitation and is particularly useful in root dissections
MR, using retrograde flow dephasing across the aortic valve on steady state free precession
true or false: proximal dissections may rupture into the pericardium, resulting in hemopericardium
true
provides the best imaging for the intima
transesophageal echocardiography
inciting event in intramural hematoma
intimal microtear
IMH is classified by the
Stanford system
describes internal erosion into the aortic media and typically manifests on the background of severe atherosclerotic disease
penetrating atherosclerotic ulcer
PAU commonly occurs in the
descending aorta
area with PAU with worst prognosis
aortic root or along the proximal ascending aorta
typically has a crater-like shape which extends beyond the calcified intima of the aorta, while complex ulcerated plaques are often more jagged appearing and do not extend beyond the intima
penetrating atherosclerotic ulcer
when PAU and IMH are seen together, complications include
formation of saccular aneurysm, aortic rupture and dissection
focal irregular outpouching of the aorta secondary to intimomedial disruption, with extravasation contained by a variable amount of adventitia and by the surrounding mediastinal tissue
aortic pseudoaneurysm
most common site of traumatic thoracic pseudoaneurysm
aortic isthmus, the narrowing between the distal arch and ligamentum arteriosum
post operative pseudoaneurysms are typically seen along the
ascending aorta at the sites of aortic puncture, annulation and/or cross-clamping
thoracic aortic pseudoaneurysms may be complicated by
aortoenteric and/or aortobronchial fistulas, mediastinal hemorrhage, hemothorax and pulmonary hemorrhage
aortic fistulas that common present with hematemesis and /or hemoptysis
aortoesophageal and aortobronchial
those with traumatic injuries in this aortic segment rarely survive
aortic root
graft containing an attached prosthetic valve is termed a
composite graft
synthetic grafts are composed of polyethylene and appear slightly hyper/hypo to the aorta on noncontrast CT but hyper/hypoattenuating to the aorta in CTA
slightly hyperattenuating to the aorta on noncontrast CT but hypoattenuating to the aorta on CTA
grafts may also be placed in the native aorta without resection, termed the ______ resulting in a soft tissue density surrounding the graft representing fluid and thrombosis within the native aorta
inclusion technique
technique in which the distal aspect of the aorta is left floating in the native aorta, can mimic a dissection
elephant trunk
in the immediate postoperative perior, perigraft air can be normal and should eventually resolve by
6 weeks postsurgery
perigraft fluid and soft tissue can also be normal, representing organizing hematoma/fibrosis or edema, and lasts for
months to years following repair
contained rupture that manifests as a contrast-containing collection contiguous with the aortic lumen, usually occuring at the anastomotic margins
postoperative aneurysm
can be mistaken for contrast leak in CT, mimicking a pseudoaneurysm in postoperative repair of aorta
graft reinforcements sych as fely and pledgets which are hyperattenuating
entails placement of a metallic stent-graft into the aorta via an endovascular approach
thoracic endovascular aortic repair
indications for TEVAR (thoracic endovascular aortic repait) include
aortic dissection, PAU, pseudoaneurysm and enlarging aneurysm
characterized by contrast extenral to the stent graft and represents continued blood flow within the exlcuded aortic lumen, which can result in expansion of an aortic aneurysm, pseudoaneurysm or dissection false lumen with increased risk for rupture
endoleak
type of endoleak that is most common and occurs at the proximal or distal margins of the stent graft
Type 1; type 1a- proximal; type 2v- distal
type of endoleak that has retrograde opacification of the excluded aortic lumen through an aortic branch vessel such as an intercostal or bronchial artery within the thorax and inferior mesenteric or lumbar arteries in the abdomen
type 2
type of endoleak that results from device failure, with contrast leaking through a fracture or defect in the stent graft
type 3
type of endoleak that is caused by graft wall porosity and does not require repair. this is usually seen in anticoagulated patients as a blush of contrast around the stent graft on catheter angiography around the time of stent placement
type 4
type of endoleak that is referred to as endotension leak, is a diagnosis of exclusion in which there is expansion of the excluded aortic lumen without a visible contrast leak
type 5
refers to inflammation of the aortic wall (specifically the media and/or adventitia), which may be focal/segmental or multifocal, may also affect large and small branch vessels and is broadly classified into noninfectious and infectious causes
aortitis
infectious aortitis is now most commonly caused by
staphylococcus aureus and Salmonella
giant cell arteritis and Takayasu arteritis predominantly affects the
ascending aorta, aortic arch and branch vessles
acute complications associated with aortitis include
intramural thrombus and aneurysm formation
inflammatory wall thickness size in aortitis
greater than 3mm
more specific sign of mural inflammation and may be reduced or absent after initiation of treatment
intramural enhancement
valuable tool for assessment of aortitis
PET-CT with 18F-FDG
aortic tumors include
leiomyosarcomas, hemangioendotheliomas, fibrosarcomas, myxoid sarcomas and angiosarcomas
most aortic tumors are ____ and will typically manifest on both CT and MR as an eccentric, pedunculated and/or lobulated intramural filling defect
sarcomas
