IMAGING the AORTA Mirvat Alasnag FACP, FSCAI, FSCCT, FASE June 1 st, 2011
September 11, 2003 Family is asking $67 million in damages from two doctors
Is it an aneurysm? Is it a dissection? What type of dissection? Is it a transection? Is it an atheroma? Is it a penetrating ulcer? Is it. Is it. Is it. Questions
CTA? MRA? TTE? TEE? WHAT OTHER 3 LETTER ABBREVIATION? ABC? XYZ? How do we decide which is appropriate?
THE PATIENT STABLE BODY HABITUS CORONARY IMAGING AV IMAGING ARCH VESSELS IMAGING THE PLAN SURGERY ENDOVASCULAR REPAIR Depends.. CONSERVATIVE
AoD evaluation pathway American College of Cardiology Foundation, et al. J Am Coll Cardiol 2010;55:1509-1544 Copyright 2010 American College of Cardiology Foundation. Restrictions may apply.
American College of Cardiology Foundation, et al. J Am Coll Cardiol 2010;55:1509-1544
TEE CT MRI American College of Cardiology Foundation, et al. J Am Coll Cardiol 2010;55:1509-1544
American College of Cardiology Foundation, et al. J Am Coll Cardiol 2010;55:1509-1544
CXR 90% have abnormal CXR Widened mediastinum Abnormal aortic contour Pleural effusion Deviation of trachea, mainstem bronchi, or esophagus Intimal calcium visable & distant from edge (calcium sign) TEE Advantage: 97-100% sensitive & 97-99% specific Availability No radiation or contrast Functional data including AV & LV eval Disadvantage: Artifact & operator dependant
CT Advantages 1. Availability 2. Image entire aorta (lumen, wall, & periaortic regions) 3. Identify anatomic variants & branch 4. Distinguish types of acute aortic syndromes (i.e. intramural hematoma, penetrating ulcer, & AoD) 5. Short acquisition time 6. 3-dimensional data 7. Gating: image the aortic root & coronaries 8. Sensitivity:83-100% & specificity:98% - 99% Disadvantage Radiation & contrast
Figure 1. Stanford type B aortic dissection on volume-rendered 64-slice multidetector CTA with compressed true lumen (TL) and expanded false lumen (FL). Nienaber C A et al. Circ Cardiovasc Imaging 2009;2:499-506 Copyright American Heart Association
Figure 7. Sixty-four slice MDCT angiogram of a patient with para-anastomotic aneurysm (arrow) after previous open surgery (left). Nienaber C A et al. Circ Cardiovasc Imaging 2009;2:499-506 Copyright American Heart Association
Magnetic Resonance Imaging Advantages Sensitivities & specificities exceed CT & TEE Identify anatomic & branch involvement AV & LV eval Disadvantages Prolonged duration of acquisition Inability to use Gd with renal dysfx CI: Claustrophobia, metallic implants or PPM Lack of availability on an emergency basis Angiography Advantages Gold standard Shows all anatomy & branches 94% specific & 88% sensitive Disadvantages Invasive & contrast use
Figure 4. Contrast-enhanced MRA of chronic type B dissection originating from the aortic arch region in MIP (A) and as volume-rendered 3D reconstruction (B). Nienaber C A et al. Circ Cardiovasc Imaging 2009;2:499-506 Copyright American Heart Association
Condition Initial Follow up Acute TEE w Doppler MRI w Gd & 3D angioscopy CT w contrast Chronic TEE w Doppler MRI w Gd & 3D angioscopy CT w contrast & 3D reconstruction MRI/MRA Catheterization Nienaber C A et al. Circ Cardiovasc Imaging 2009;2:499-506
GUIDELINES American College of Cardiology Foundation, et al. J Am Coll Cardiol 2010;55:1509-1544
American College of Cardiology Foundation, et al. J Am Coll Cardiol 2010;55:1509-1544 1 Measurements of aortic diameter should be taken at reproducible anatomic landmarks, perpendicular to the axis of blood flow, and reported in a clear and consistent format. (Level of Evidence: C) 2 For measurements taken by computed tomographic imaging or magnetic resonance imaging, the external diameter should be measured perpendicular to the axis of blood flow. For aortic root measurements, the widest diameter, typically at the midsinus level, should be used. (Level of Evidence: C) 3 For measurements taken by echocardiography, the internal diameter should be measured perpendicular to the axis of blood flow. For aortic root measurements the widest diameter, typically at the mid-sinus level, should be used. (Level of Evidence: C)
4 Abnormalities of aortic morphology should be recognized and reported separately even when aortic diameters are within normal limits. (Level of Evidence: C) 5 The finding of aortic dissection, aneurysm, traumatic injury and/or aortic rupture should be immediately communicated to the referring physician. (Level of Evidence: C) 6 Techniques to minimize episodic and cumulative radiation exposure should be utilized whenever possible. (Level of Evidence: B) American College of Cardiology Foundation, et al. J Am Coll Cardiol 2010;55:1509-1544
Marfan: 1. At diagnosis 2. At 6 months to determine rate of enlargement 3. Annually if stable 4. If Ao > 4.5 cm or rapid growth, more frequent Loeys-Dietz syndrome or confirmed genetic mutation predisposing to aneurysms & dissections (TGFBR1, TGFBR2, FBN1, ACTA2, or MYH11): 1. At diagnosis 2. At 6 months to determine rate of enlargement 3. Yearly MRA from cerebrovascular to pelvis circulation Turner syndrome: 1. At diagnosis (bicuspid aortic valve, coarc, or dilated As Ao) 2. If initial imaging is normal & no risk factors for AoD, repeat imaging every 5-10 years or if clinically indicated. 3. If abnormalities exist, annual imaging
Normal anatomy of the thoracoabdominal aorta with standard anatomic landmarks for reporting aortic diameter as illustrated on a volume-rendered CT image of the thoracic aorta American College of Cardiology Foundation, et al. J Am Coll Cardiol 2010;55:1509-1544 Copyright 2010 American College of Cardiology Foundation. Restrictions may apply.
Artifact mimicking dissection American College of Cardiology Foundation, et al. J Am Coll Cardiol 2010;55:1509-1544 Copyright 2010 American College of Cardiology Foundation. Restrictions may apply.
Arch aneurysm with dissection flap American College of Cardiology Foundation, et al. J Am Coll Cardiol 2010;55:1509-1544 Copyright 2010 American College of Cardiology Foundation. Restrictions may apply.
Figure 5. TEE assessment of thoracic aortic disease: Acute type A dissection visualized in longitudinal and short-axis view; white arrows indicate dissection lamella (A) and an intimal tear in close proximity of the aortic leaflets (B). Copyright American Heart Association Nienaber C A et al. Circ Cardiovasc Imaging 2009;2:499-506
Lets move from the hypothetical. CASES
SCENARIO 1 32 Y FEMALE 2 WK POST DELIVERY SEVERE CHEST PAIN & UNCONTROLLED BP
SCENARIO 2 66 Y OLD FEMALE MULTIPLE CVS RF SEVERE CHEST PAIN & ECG changes
SCENARIO 3 68 YEAR OLD MALE MULTIPLE CVS RF ASYMPTOMATIC CXR: WIDE MEDIASTINUM
SCENARIO 4 28 Y OLD MALE RENAL FAILURE & SHOCK POST CV LINE INSERTION
SCENARIO 5 72 Y OLD MALE THORACIC AORTIC ANEURYSM SINCE 2009 ASYMPTOMATIC
CONCLUSION: The patient The plan The center What is readily available? MRA, CTA, TEE What is the comfort level of the interpreter? What protocol is agreed upon with the surgeons?
ECHO: AVAILABILITY INTRAOPERATIVE USE