SUNDAY Update on Acute Aortic Syndrome Diana Litmanovich, MD Learning objectives To be familiar with the definition, natural history, and imaging findings of acute aortic syndrome, including: I. Aortic Dissection II. Intramural Hematoma III. Penetrating Aortic Ulcer Diana Litmanovich, MD Current updates in acute aortic syndrome I. Aortic dissection Root: up to 4 cm Ascending: up to 4 cm Descending: up to 3 cm Abdominal: up to 2.0 cm Ab A Spontaneous dissections almost always originate in the thoracic aorta and extend to involve the abdominal aorta 2003 by Radiological Society of North America Aortic Dissection risk factors Age 50-75 years: M > F 2:1 Hypertension Age < 40 years: M = F Connective tissue disorder Bicuspid aortic valve, coarctation Pregnancy Crack cocaine abuse Prior cardiac or aortic valve surgery Mortality by 50% in last 20 years
Aortic Dissection: classification Aortic Dissection: MDCT diagnosis Presence Type Distal extent True and false lumens Entry and re-entry tears Complications SUNDAY Ascending ± descending 75% Mortality 58% unrepaired Descending only 25% May involve arch Mortality 11% unrepaired Intimal flap and displaced intimal calcifications Aortic Dissection: MDCT diagnosis Presence Type Distal extent True and false lumens Entry and re-entry tears Complications Type A Ascending aorta Type A: Ascending and descending aorta
SUNDAY Type B : Descending aorta only Aortic Dissection: MDCT diagnosis Presence Type Extent True and false lumens Entry and re-entry tears Complications Extent of aortic dissection - proximal Most commonly extends into L. Common Iliac artery False lumen ends blindly Aortic Dissection: MDCT diagnosis Presence Type Extent True and false lumens Entry and re-entry tears Complications
True lumen Larger than true Left renal artery Acute angle F SUNDAY Prone to dilate, thrombose May rupture Cobwebs F Aortic Dissection: MDCT diagnosis Larger than true Left renal artery Acute angle Prone to dilate, thrombose May rupture Cobwebs F F Presence Type Extent True and false lumens Entry and re-entry tears Complications Entry and re-entry tears Aortic Dissection: MDCT diagnosis Presence Type Extent True and false lumens Entry and re-entry tears Complications
SUNDAY Aortic Dissection: Complications Involvement of aortic branches Involvement of aortic branches Perfusion deficit Impending rupture Rupture Involvement of ductus arteriosus Signs of potential perfusion deficit Concave True lumen F Intimo-intimal intussusception: Windsock sign
Hemopericardium Dissection into pulmonary artery adventitia SUNDAY Acute extravasations and hemopericardium Time-resolved CT Imaging of the Aorta Sommer, et al. JTI 2010 CT versus MR When to use MR? Allergic reaction to contrast Mild and moderate renal failure: GFR > 30 Severe renal failure non-contrast MRI Annual follow-up of young patients MRI Balanced SSFP Sequence Lohan et al. MRI Clinic N Am.2008
SUNDAY MRI GD enhanced Treatment of Aortic Dissection Ascending aorta : Surgery Stent graft Simultaneous endoluminal stent graft repair of descending aorta Descending aorta: Medical management in most cases Endoluminal stent graft in selected cases Percutaneous aortic fenestration +/- stent graft Pradhan S et al. Ann Thorac Cardiovasc Surg 2007 Gated CTA -? Thoracic inlet symphysis pubis 75 ml at 4 ml/sec 30 ml saline Aortic Arch 150 HU Axial, MPR, 3D VR Not routinely used Myocardial perfusion jeopardy Aortic valve involvement Prospective vs. retrospective gating lower radiation dose equivalent image quality Wu W, et all. AJR, 2009 Halpern EJ. Radiology. 2009 Fleischmann et all. Semin Cardiovasc Surgery, 2008
Pulsation Motion Artifacts SUNDAY V. Raptopoulos, PB Boiselle, N. Michailidis, J Handwerker, A Sabir, J A. Edlow, I. Pedrosa, JB. Kruskal, MDCT Angiography of Acute Chest Pain: Evaluation of ECG-Gated and Non-gated Techniques. AJR, 2005 Fleischmann D. Sem Thorac Cardiov Surg 2008 Entry and Re-entry Tears Location and Extent of the Flap Litmanovich D, Zamboni GA, Hauser TH, Lin PJ, Clouse ME, Raptopoulos V. ECG-gated chest CT angiography with 64-MDCT and tri-phasic IV contrast administration regimen in patients with acute non-specific chest pain. Eur Radiol. 2008 Coronary Arteries Involvement
SUNDAY Prospective and Retrospective ECG Gating for Thoracic CT Angiography 64-MDCT system GE Prospective CTDI vol 30 mgy DLP 834 mgy-cm ED 11.6 msv Retrospective CTDI vol 75 mgy DLP 2,550 mgy-cm ED 35 msv Copyright 2011 by the American Roentgen Ray Society Wu W. et al. AJR. 2009 ED 2.0-3.3 msv Total IV contrast 60 ml All but 1/ 64 cases diagnostic for aorta, PA, coronary arteries Prospective 100 kv: 1.9 msv 120 kv: 5.3 msv Similar length (23 cm) Similar image quality Retrospective 100kV: 4.1 msv 120 kv: 9.5 msv Blanke P. et al. Radiology 2010 II. Intramural Hematoma 1. Rupture of the vasa vasorum 2. Spontaneous thrombosis of the false lumen 3. Penetrating atherosclerotic ulcer allowing blood to gain access to the aortic media No flow in false channel!!! 2003 by Radiological Society of North America IMH 2 types Traumatic usually good prognosis Non-traumatic worse prognosis - Type A intramural hematoma - Coexisting PAU - Age > 70 - Aortic diameter > 5.2 cm - Increasing aortic diameter - Hematoma thickness > 1.0 cm Evangelista et al. Circulation 2005
IMH natural history IMH - CT SUNDAY CT Non-contrast scan is critical!!! IMH - CT Type A IMH Estrera et al. Circulation 2009 IMH vs. thrombus IMH and Dissection
SUNDAY IMH CT and MRI III. Penetrating Atherosclerotic Ulcer 2-8% of acute aortic syndromes Low MR signal surrounding the ascending aorta Low density tissue surrounding the ascending aorta Symptoms mimic aortic dissection Concomitant AAA Complications IMH, dissection, pseudoaneurysm, rupture 2003 by Radiological Society of North America Relationship PAU IMH Vilacosta I et al. Am Heart J 1997 Nakamura et al. Ann Thorac Surg 2006 Uncontrollable pain and/or Increasing pleural effusion PAU progression over time 1 Year later Open surgical or endovascular stent-graft repair Ganaha et al. Circulation 2002
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