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KEY FACTS

Terminology
- Congenital systemic connective tissue disorder; skeletal, cardiovascular, and ocular abnormalities
Imaging
- Radiography - Ascending aortic aneurysm - Cardiomegaly - Pectus deformity, scoliosis, scalloped vertebrae - Pneumothorax, apical bullae
- CT - Annuloaortic ectasia, aneurysm - Aortic rupture: Crescent sign, hematoma - Dissection: Intimal flap, true/false lumen
- Echocardiography - At diagnosis to assess ascending aorta and 6 months thereafter to determine rate of enlargement
- MR: Similar to CT in sensitivity
Top Differential Diagnoses
- Familial thoracic aortic aneurysm
- Ehlers-Danlos syndrome
- Bicuspid aortic valve
Pathology
- Mutation in FBN1 gene encoding for fibrillin 1
- Autosomal dominant; 25% de novo mutations
- Microscopy: Cystic medial necrosis
Clinical Issues
- Cardiac/vascular abnormalities
- Pulmonary abnormalities
- Thoracic skeletal abnormalities
Diagnostic Checklist
- Consider Marfan syndrome in young patients with ascending aortic aneurysm &/or aortic dissection

TERMINOLOGY

Definitions
- Marfan syndrome (MFS): Congenital systemic connective tissue disorder characterized by skeletal, cardiovascular, and ocular abnormalities

IMAGING

Radiographic Findings
- Ascending aortic aneurysm: Mediastinal widening, right superior cardiomediastinal contour abnormality
- Cardiomegaly: Aortic/mitral regurgitation, cardiomyopathy
- Pectus deformity (excavatum, carinatum), scoliosis, scalloped vertebral bodies
- Pneumothorax, apical bullae

CT Findings

NECT

- **Annuloaortic ectasia****/****aneurysm**: Effacement of sinotubular junction (60-80% of patients)
        - Lack of normal transition between aortic root and tubular portion of ascending aorta
        - Indication for surgery: Diameter > 4.5 cm
- **Aortic rupture**, often contained
        - **Crescent sign**: Crescentic eccentric aortic high-attenuation area
        - **Hematoma**: Mediastinal high attenuation, hemothorax, hemopericardium

CTA

- More sensitive than radiography
- Direct visualization
        - Dissection: Intimomedial defect, true/false lumen
        - Rupture: Active extravasation

MR Findings
- Equivalent to CT, similar accuracy
- Direct visualization of aortic aneurysm and dissection
- Cine MR and phase-contrast imaging are optimal for valve assessment: Aortic &/or mitral regurgitation
- 4D flow MRA provides detailed hemodynamic assessments, including pulse wave velocity (PWV) and peak systolic velocity, to predict future aortic events
Echocardiographic Findings
- Initial assessment of aortic size and 6 months thereafter to determine rate of enlargement

Imaging Recommendations

Protocol advice

- Annual imaging is recommended after initial echocardiography

DIFFERENTIAL DIAGNOSIS

Familial Thoracic Aortic Aneurysm
- Sinus of Valsalva aortic aneurysm
Ehlers-Danlos Syndrome
- Aneurysm/rupture: Medium/large muscular arteries
- Systemic: Joint hypermobility, atrophic scars, easy bruising, hernias, hollow organ rupture
Bicuspid Aortic Valve
- Ascending aortic aneurysm; bicuspid aortic valve
Homocystinuria
- Cardiac: Mitral valve prolapse
- Vascular: Intravascular thrombosis
- Systemic: Tall stature, ectopia lentis, long bone overgrowth, intellectual disability
Loeys-Dietz Syndrome
- Cardiac: Patent ductus arteriosus, atrial septal defect, bicuspid aortic valve
- Vascular: Sinus of Valsalva aneurysm, arterial tortuosity, aneurysms in other arteries
- Hypertelorism, cleft palate, broad or bifid uvula, exotropia, craniosynostosis, malar hypoplasia, blue sclerae, dolichostenomelia, arachnodactyly, pectus deformity, scoliosis, joint laxity, rare developmental delay
Shprintzen-Goldberg Syndrome
- Vascular: Rare sinus of Valsalva aneurysm
- Systemic: Hypertelorism, craniosynostosis, arched palate, arachnodactyly, pectus deformity, scoliosis, joint laxity, developmental delay
MASS (Mitral, Aortic, Skin, and Skeletal Manifestations) Syndrome
- Cardiac: Mitral valve prolapse
- Vascular: Borderline/nonprogressive aortic root enlargement
- Systemic: Nonspecific skin and skeletal findings, myopia

PATHOLOGY

General Features

Etiology

- Mutation in *FBN1*gene encoding for **fibrillin 1**
- *TGFBR2* and *TGFBR1* responsible for 10% of all cases

Genetics

- Autosomal dominant; 25% de novo mutations

Microscopic Features
- Cystic medial necrosis - Accumulation of basophilic ground substance in media with cyst-like lesions; no overt cystic or necrotic changes are normally identified - Can occur in MFS, Ehlers-Danlos syndrome, and annuloaortic ectasia

CLINICAL ISSUES

Presentation

Clinical profile

- **Cardiac abnormalities**
        - Mitral valve regurgitation
                  - Children: Mitral regurgitation and heart failure, pulmonary hypertension, death in infancy
                  - > 50% auscultatory/echocardiographic evidence of mitral valve dysfunction, typically prolapse
                  - Progression of mitral valve prolapse to mitral regurgitation by adulthood
        - Aortic valve regurgitation: Late occurrence from aortic anulus stretching
        - Tricuspid valve prolapse
        - Dilated cardiomyopathy (uncommon)
- **Vascular abnormalities**: Most common life-threatening manifestations
        - **Annuloaortic ectasia**and **aortic aneurysm**
        - **Aortic dissection**
                  - Often type A
                  - Acute-onset heart failure typically from severe aortic insufficiency
                  - Extension to coronary arteries; myocardial infarction or sudden cardiac death
                  - Dilatation/dissection of descending thoracic/abdominal aorta
        - Dilatation of pulmonary trunk
- **Pulmonary abnormalities**
        - Bullae: Predisposed to spontaneous pneumothorax
- **Thoracic skeletal abnormalities**
        - Pectus deformity; can contribute to restrictive lung disease
- **Revised Ghent nosology (Ghent 2)**
        - **Goals**: Identification of patients with higher risk for aortic aneurysm or dissection; simplicity of use of diagnostic criteria; allowance for early diagnosis; consideration of availability and costs of diagnostic tests; better definition of entities, such as familial ectopia lentis, MASS phenotype, and mitral valve prolapse syndrome; and delineation of triggers for alternative diagnoses, such as Loeys-Dietz syndrome
        - **5 major changes** (in comparison with Ghent 1)
                  - More diagnostic emphasis on aortic root aneurysm/dissection and ectopia lentis
                  - More prominent role of molecular genetic testing (i.e., *FBN1*; *TGFBR1* and *TGFBR2*)
                  - Complete removal of some clinical criteria (e.g., dilatation of main pulmonary artery, dilatation or dissection of descending thoracic or abdominal aorta, increased axial length of globe and abnormally flat cornea, hypoplastic iris or hypoplastic ciliary muscle causing decreased miosis, joint hypermobility, spondylolisthesis, highly arched palate, and recurrent or incisional hernia, calcification of mitral anulus, apical blebs of lung), or mitigation of diagnostic relevance of dural ectasia, or adding or modifying clinical criteria, such as myopia > 3 diopters, hindfoot valgus, and thoracolumbar kyphosis
                  - Provision of discriminating features of alternative diagnoses, such as Loeys-Dietz syndrome
                  - Provision of context-specific recommendations for patient counseling and follow-up
        - **Absence of family history**
                  - Aortic root diameter (Z-score ≥ 2) and ectopia lentis = MFS
                  - Aortic root diameter (Z-score ≥ 2) and causal *FBN1*mutation = MFS
                  - Aortic root diameter (Z-score ≥ 2) and systemic score ≥ 7 points = MFS
                  - Ectopia lentis and causal *FBN1*mutation with known aortic root dilatation = MFS
        - **In presence of family history**
                  - Ectopia lentis and family history of MFS = MFS
                  - Systemic score ≥ 7 points and family history of MFS = MFS
                  - Aortic root diameter (Z-score ≥ 2 above 20 years old, ≥ 3 below 20 years) and family history of MFS = MFS
        - **Scoring of systemic features** (maximum total score 20 points)
                  - Wrist and thumb sign = 3 points (wrist or thumb sign = 1 point)
                  - Pectus carinatum deformity = 2 points (pectus excavatum or chest asymmetry = 1 point)
                  - Hindfoot deformity = 2 points (plain pes planus = 1 point)
                  - Protrusio acetabuli = 2 points
                  - Reduced upper segment:lower body segment ratio and increased arm/height and no severe scoliosis = 1 point
                  - Scoliosis or thoracolumbar kyphosis = 1 point
                  - Reduced elbow extension = 1 point
                  - Facial features (3/5) = 1 point (dolichocephaly, enophthalmos, downslanting palpebral fissures, malar hypoplasia, retrognathia)
                  - Pneumothorax = 2 points
                  - Skin striae = 1 point
                  - Myopia > 3 diopters = 1 point
                  - Mitral valve prolapse (all types) = 1 point
                  - Dural ectasia = 2 points

Demographics

Sex
```
- M = F
```

Epidemiology

- Incidence: 1 in 3,000-5,000 individuals

Natural History & Prognosis
- Improved prognosis with annual imaging, medical/surgical intervention
- Higher aortic dissection risk during pregnancy
Treatment
- β-adrenergic receptor blockade
- Restriction of vigorous exercise
- Surgical reconstruction: Elective according to aortic diameter or if dissection or rupture - Indications for surgery - Ascending aorta - Diameter ≥ 4.5 cm - Diameter ≥ 4.5 cm in family history of early dissection, rapid growth defined as ≥ 0.5 cm/year, and significant aortic regurgitation - Aortic arch - Diameter > 5.0 cm - Descending thoracic aorta - Diameter > 5.0 cm

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References

Selected References

Differential diagnosis

Dilated Aorta

DDX:9daee273-f1e9-4cf9-a979-8990a9b82e40

Cases

{'cases': [{'authors': [{'key': 'd06dfcc4-4b3a-4c2a-b6ae-6ac081d23b98', 'value': 'Jonathan Hero Chung, MD'}, {'key': '3d1e4c57-c1cf-4c89-b0f0-5d82b29a31e1', 'value': 'Suhny Abbara, MD, FACR, MSCCT, FNASCI'}], 'caseVersionId': 'e3fd2ed7-6fcc-4541-bbfd-aac36ee456ab', 'description': "Oblique coronal volume-rendered (#1) and short axis (#2) contrast-enhanced CTAs show annuloaortic ectasia with "tulip bulb" or "pear-shaped" dilation of the aortic annulus (white arrows, #1), the sinus of Valsalva (black arrows), and the more distal ascending aorta (annuloaortic ectasia). \n\nSagittal oblique MIP (#3) demonstrates effacement of the sinotubular junction. There is superior displacement of the right coronary artery origin (open arrow), and scoliosis related to patient's underlying diagnosis of Marfan syndrome. \n\nAxial contrast-enhanced CT (#4) shows upper lung paraseptal and bullous emphysema (open black arrows), which is another common manifestation of Marfan syndrome, predisposing the patient to spontaneous pneumothoraces.", 'history': 'Marfan patient with history of ascending aortic aneurysm.', 'imagePoolId': 'ad500e5f-0216-481c-ac7b-34782bc7635e', 'name': 'Annuloaortic ectasia', 'teachingPoint': None, 'demographics': '43 Years old male'}], 'caseType': 'typical', 'name': 'TYPICAL'}

Images

Selected Images

Graphic compares a normal ascending aorta (left) with a well-defined sinotubular junction and annuloaortic ectasia with sinotubular junction effacement (right).

Coronal oblique CECT shows aneurysms associated with bicuspid aortic valve (left) and Marfan syndrome (MFS) (right) to exemplify annuloaortic ectasia. Note that a sinotubular junction is still identifiable in dilatation due to bicuspid aortic valve but is effaced in MFS due to dilated aortic root.

PA radiograph of the chest in a patient with MFS shows an abnormal convexity along the right superior cardiac silhouette. This finding is often associated with a dilated ascending aorta. In young patients, it is commonly associated with bicuspid aortic valve and MFS.

Axial chest CTA in the same patient shows dilatation of the sinuses of Valsalva (4.7.x 5.0 x 5.0 cm). Three measurements bisecting each sinus are usually obtained at this level.

Axial CECT in a young patient with MFS shows symmetric dilation of all sinuses of Valsalva.

Coronal CECT in the same patient shows effacement of the sinotubular junction , which is characteristic of MFS. Note diffuse dilatation of the entire ascending thoracic aorta, demonstrating a morphology often referred to as the tulip bulb sign. The pulmonary trunk appears smaller than the aorta. Normally, the pulmonary artery is of the same size as the ascending aorta.

Coronal CECT 3D surface rendering in the same patient shows the so-called tulip bulb configuration of the ascending thoracic aorta characteristically seen in MFS due to dilatation of the aortic root with normal appearance of the arch and descending thoracic aorta.

PA chest radiograph in a patient with MFS and acute aortic syndrome shows no specific cause of the symptoms reported in this individual. A normal radiograph does not exclude aortic dilatation or dissection.

Axial CECT in the same patient shows marked aortic root dilatation . Note disproportion in the diameter of the pulmonary trunk, which should typically be the same size as the ascending aorta. At the higher level, there is an intimomedial defect representing ascending aortic dissection .

Oblique sagittal CECT in the same patient shows the classic tulip bulb appearance due to annuloaortic ectasia.

Axial CECT in a young pregnant woman with MFS with acute chest pain shows an intimomedial defect ascending into the descending aorta . Note dilation of the ascending thoracic aorta.

Coronal oblique CECT in the same patient shows an intimomedial defect extending along the entire ascending aorta. Note effacement of the sinotubular junction , completely absent in this case, a very characteristic feature seen in MFS involving the ascending aorta.

Sagittal oblique CECT in the same patient shows an extensive Stanford type A intimomedial defect involving the entire thoracic aorta. Dissection is a known complication of MFS, and pregnant individuals are under particular risk to develop such a complication.

Axial chest CTA MIP reformation in a patient with MFS shows dilatation of the pulmonary trunk and central pulmonary arteries. (Courtesy L. Heyneman, MD.)

Axial CTA in a patient with MFS shows marked dilatation of the aortic root and pectus excavatum deformity . These are major diagnostic criteria for MFS. (Courtesy L. Heyneman, MD.)

Axial NECT in the same patient shows bilateral apical bullae . This may lead to secondary spontaneous pneumothorax in patients with MFS. (Courtesy L. Heyneman, MD.)

Axial CECT in a patient with MFS who underwent a modified Bentall reconstruction of the ascending aorta shows pseudoaneurysm of the left coronary button .

Coronal oblique CECT in the same patient shows an abnormal contract collection adjacent to the proximal aspect of the graft. Note distal anastomotic felts . Pseudoaneurysm of the coronary buttons is overall an uncommon complication that occurs more frequently in patients with MFS.

Axial CECT in a patient with MFS who underwent a modified Bentall reconstruction of the aorta shows bulb-like dilatation of the left coronary button . Patients with MFS are more prone to develop dilation &/or pseudoaneurysm of the coronary buttons.

Oblique sagittal SSFP MR in a patient with MFS and ascending aortic aneurysm shows a diastolic jet across the aortic valve, which constitutes one of the major cardiovascular criteria for MFS.

Oblique gadolinium-enhanced MRA in the same patient shows dilatation of the aortic root with tulip bulb-like morphology. Volumetric acquisition and postprocessing reformations are some of the advantages of MRA over other sequences.

Oblique sagittal SSFP and dark blood (HASTE) MR in a patient with MFS show dilatation of the proximal ascending aorta with effacement of the sinotubular junction. Both sequences are suitable to depict ascending aortic morphology.

Additional Images

AP chest radiograph in a patient with MFS shows enlargement of the ascending aorta and cardiomegaly.

PA chest radiograph in a patient with MFS shows an elongated thorax and dilatation of the ascending and descending aorta.

Coronal CTA in the same patient shows typical findings of annuloaortic ectasia with obliteration of the sinotubular ridge and dilatation of the ascending aorta and the sinuses of Valsalva.

Lateral chest radiograph in the same patient shows dilatation of the ascending aorta from annuloaortic ectasia.

Coronal CECT in the same patient shows annuloaortic ectasia and an ascending aortic dissection with a visible intimal flap .

Axial CECT in the same patient shows an ascending aorta dissection with a visible intimal flap . Note dural ectasia manifesting with scalloping of the vertebral body .

DSA of the intracranial arteries shows the intracranial carotid artery as being markedly elongated, dilated, and redundant in the supraclinoid segment . Patients with MFS may have aneurysms of the extracranial and intracranial carotid arteries. Redundancy in carotid arteries may be associated with dissection.

DSA shows marked redundancy of the vertebral artery . The redundancy is due to the structural abnormalities of the artery.

33 KiB Raw Permalink Blame History

KEY FACTS

Terminology

Imaging

Top Differential Diagnoses

Pathology

Clinical Issues

Diagnostic Checklist

TERMINOLOGY

Definitions

IMAGING

Radiographic Findings

CT Findings

NECT

CTA

MR Findings

Echocardiographic Findings