The Radiologist s role in Acute Aortic Syndrome.

Transcription

1 The Radiologist s role in Acute Aortic Syndrome. Poster No.: C-1525 Congress: ECR 2015 Type: Educational Exhibit Authors: R. Quintana de la Cruz, M. M. Rienda, F. Jiménez Aragón, E. Domínguez Ferreras, A. Pinardo, M. E. Banegas Illescas, A. Pinar, M. L. Rozas Rodríguez, M. T. Gomez San Roman; Ciudad Real/ ES Keywords: Aneurysms, Diagnostic procedure, CT-Angiography, Cardiovascular system DOI: /ecr2015/C-1525 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 40

2 Learning objectives 1. Describing the entities (Fig. 1 on page 3 ) comprising the acute aortic syndrome (AAS) and its pathophysiological mechanisms, clinical features and assessment of the radiological findings 2. Understanding the role of the radiologist as a fundamental part of the diagnosis of this syndrome. 3. Displaying case studies as examples of these injuries. Page 2 of 40

3 Images for this section: Fig. 1 Radiology Assistant Page 3 of 40

4 Background The AAS is a medical emergency, either spontaneous or secondary to trauma, which includes entities that affect the aortic wall, which are clinically indistinguishable, whose diagnosis is based on the image (CT technique of choice). Traditionally embraces the following entities: 1. Aortic Dissection (AD). 2. intramural hematoma (IMH). 3. penetrating atherosclerotic ulcer (PAU) The image technique of choice for the AAS is CT, whose protocol is: CT without contrast: - Differential diagnosis with intramural hematoma Assess intimal calcifications. Intravenous contrast CT: - Arterial phase (delay 20 sec) and venous phase(delay 60 sec) - 3 cm above the supra-aortic trunks to proximal femoral arteries 1. Aortic Dissection (AD): Fig. 4 on page 14 Fig. 5 on page 15 Fig. 6 on page 16 Fig. 7 on page 17 Fig. 8 on page 18 Fig. 18 on page 28Fig. 19 on page 29Fig. 20 on page 30Fig. 21 on page 31Fig. 22 on page 32 Page 4 of 40

5 The most frequent (80%) and severe form of AAS. It is characterized by the creation of a false lumen in the middle layer of the aortic wall, and there are two lumens: the true lumen (contained entirely by the intima) and the false lumen (contained entirely within the medial layer of the aorta). It begins with the formation of a tear in the intima of the aorta, which exposes the underlying middle layer to pulsatile blood flow, which penetrates this layer and extending distally dissected, creating a false lumen between the intima and media, with subsequent displacement vascular endothelial towards the aortic lumen. And by shear forces, it can produce a tear in the inner part of the dissected aortic wall (intimal flap) and produce additional exit or input zones. Classification: 1. Depending on the presence and location of primary tears and retrograde or antegrade extension of the dissection: -Stanford Classification's, Fig. 2 on page 13 Fig. 3 on page 13 the most widely used, is based on whether the dissection extends to the ascending aorta or not, taking as reference the location of damage relative to the outlet of the left subclavian artery. Recognizes two types of involvement: Stanford A, cases with involvement of the ascending aorta; is the most common. Stanford B, cases with involvement of the descending aorta. Stanford classification addition to theorical is a great relevance in disease management. -De Bakey Classification's Fig. 3 on page 13: Type I: ascending and descending Aorta are affected Fig. 4 on page 14 TypeII: onlyinvolves the ascendingaorta Type III: only descending Aorta is affected Fig. 18 on page 28 Fig. 20 on page 30 Page 5 of 40

6 2. Depending on time of evolution it can be classified into acute <2 weeks and chronic > 2 weeks. Location: The most common site of primary intimal tear is: 65% ascending aorta (1-5 cm above the right Valsalva sinus) 20% proximal descending aorta below the left subclavian 10% transverse aortic arch and 5% thoracoabdominal aorta. Predisposing factors of Aortic Dissection (AoD): -Age (affects patients between 5th and 7th decades of life, being more frequent in males (3/1). Under 40 frequency is similar in both sexes, due to the increased frequency of AoD in the third quarter in pregnant women). -Hypertension (HT) which is the second major factor. -Congenital anomalies of the aortic valve, -Inherited disorders of connective system with cystic medial degeneration (Marfan, Ehlers-Danlos...) -Direct Traumatisms: Direct tears tend to cause more localized bruising or aortic frank rupture than classical Dao -Iatrogenics: secondary to invasive cardiac surgery or secondary angiographic procedures. -Other factors: cocaine consumption, etc. Page 6 of 40

7 Clinically is characterized by - Severe (96%) pain, sudden onset of tearing, pulsatile character, migratory following the dissection direction:- Located in the front of the chest, neck and jaw when AD is in the proximal aorta, or - Located in the interscapular area, abdomen or back if AD is distal. It is accompanied by shock with preserved or high blood pressures. Less common symptoms at presentation of AD, with or without associated chest pain are: - Heart failure due to severe aortic insufficiency in AD proximal. - Syncope without focal neurological signs in proximal breaking AD in the pericardial cavity with tamponade or, less frequently, by breaking down aortic dissection in the left pleural space. - Cerebral vascular accident Fig. 8 on page 18, peripherical neuropathies or paraplegia.. - Cardiac stop or sudden death. Diagnosis: 1. Because aortic dissection is an entity with diverse clinical presentation is necessary to maintain a high index of suspicion by the physician to establish a rapid and accurate diagnosis. The three clinical factors most frequently associated with aortic dissection include - previous history of hypertension, - sudden onset of severe chestpain and - radiating pain These factors, together with - the complementary tests: Electrocardiogram and Chest radiography with mediastinal widening on chest or image thoracic AD layered pastry and concentric adjacent to the abdominal Ao in the case of lower AD and Page 7 of 40

8 - physical examination (HTA, absence of any of peripheral pulses, the murmur of aortic insufficiency) require discarding aortic dissection. 2. Final diagnosis: The diagnosis is based on demonstrating the "flap" intimal that separates the true light of the false. A) Unenhanced CT: displacement intimal calcification into the aortic lumen is characteristic. DD: mural thrombus with peripherally displaced calcification Fig. 25 on page 35. B) Enhanced CT : -B.1) Intimal flap: Fig. 4 on page 14 Fig. 5 on page 15Fig. 6 on page 16Fig. 18 on page 28Fig. 19 on page 29 Fig. 20 on page 30, hypodense line between true and false lumen light, corresponding to the close-shifted within the true aortic lumen, thus leaving the two separate lights. The "flap" can be provided by performing a linear path, with easy to follow throughout its course, but sometimes shows some atypical events like: 1. Spiral path "flap" that makes a difference for a light respect to the other, depending on the area of the aorta. 2. Circumferential "flap" due to release of all intimate. 3. "Flap" with fusiform morphology, thickening distally by hematoma formation in the detached intimate. 4. Existence of three or more false lights (Mercedes-Benz sign ). 5. Close-intimal intussusception, where the false lumen completely surrounds the true light. -B.2) False lumen Fig. 5 on page 15: 1. Cobweb or web sign (+specific) produced by small fragments torn intima-media ranging from the outer wall of the false lumen to the intimal flap and identified as small hypodense and irregular lines 2. Beak or peak sign. (+reliably) present when the intimal flap adopts a concave shape toward the true light, thus conditioning an acute angle at the point of convergence of the flap and the wall of the false lumen. Page 8 of 40

9 3. Large, lateral and less unhanced. 4. Left renal artery beginning 5. Thrombosed with more frequency - B.3) True lumen Fig. 5 on page 15: 1. Smaller and less unhanced 2. Compressed by the false lumen (80% of cases). 3. Continue with light not dissected AD is the most common cause of aortic emergency and must be diagnosed and treated urgently because it associates a high rate of morbidity and mortality, depending on the type and extent of dissection and the presence of associated complications. There are two other etiological forms of AAS, intramural hematoma (IMH), and penetrating atherosclerotic aortic ulcer (PAU). 2.Intramural haematoma (IMH) Fig. 23 on page 33 Fig. 24 on page 34 : It involves 10-20% of the AAS. It is caused by rupture of the vasa vasorum of the average and thus has one intraparietal contained aortic bleeding. Generally intimate is respected, but can be broken and it is in these cases where the intramural haematoma is considered a precursor of aortic dissection. IMH, also known as AD without intimal tear. It is associated with hypertension. Clinically, tends to be located, with less pain irradiated than AD. It is usually located in the descending aorta (70%). Page 9 of 40

10 A) Unenhanced CT shall identify: - Circular thickening or crescent shaped hyperdense in the aortic wall that on enhanced CT will correspond to a hypodense crescent wall respect to light in enhanced CT. - Displacenment of intimal calcifications. Differential diagnosis with mural thrombus. B) Contrast CT: -Semiluna Hypodense circumferential wall adjacent to the aortic wall. The intramural haematoma is considered an atypical form of aortic dissection with a more aggressive clinical course and depends largely on its location. Its handling in terms of their location will be: 1. IMH type A (Ao ascending + descending) tend to progression and even dissection, so their driving surgical 2. IMH type B (descending Ao) usually remain stable and localized mostly, which generally allow medical supervision at the expense of evolution. Thus monitoring should be performed in the first three months, because it is not uncommon to objectify the haematoma has evolved dissection or otherwise has been completely absorbed. It is also important for management to assess other factors as are the thickness of haematoma (> 2cm >risk), whether there pericardial or pleural effusion and whether or not compress the aortic lumen. 3. Penetrating aortic ulcer (PAU) Fig. 16 on page 26 Fig. 17 on page 27 Tear or intimal erosion, secondary to an ulceration of an atherosclerotic plaque that penetrates the internal elastic lamina, with an intramural haematoma formation in the middle layer of the aorta. It can remain localized or extend a few centimeters, without forming a second light. Page 10 of 40

11 It is usually located in the descending aorta. Usually diagnosed in the context of a small intramural haematoma, but some of them may occur in asymptomatic patients. In the CT study, revealed diffuse atherosclerosis accompanied by a hyperdense crescent above and below the ulcer which corresponds to intramural haematoma and multiple intimal calcifications around the entrance of the ulcer (broked atheromatous plaque) is observed and internal displacement of mural calcium. In contrast CT atheromatous plaque is identified with a discontinuity which will form the entrance of blood to the wall identifying active blood outlet, in the event of any failure mural be further appreciated contrast output to adjacent spaces (mediastinum, pericardium and pleural space). The PAU evolution's is unpredictable, and potentially fatal and may be to: - Pseudoaneurysms (25%), - Dissection (rare extended) or - Secondary aortic rupture (8%). Often originate saccular aortic aneurysms (pseudoaneurysms) or spindle (true aneurysm). Therefore it is important to know the location (Type A or B), if it is single or multiple and if associated intramural haematoma. In acute aortic pathology there must be a differential diagnosis of aortic aneurysm rupture as a clinical entity to consider Fig. 9 on page 19, Fig. 10 on page 20, Fig. 11 on page 21, Fig. 12 on page 22 Fig. 13 on page 23 Fig. 14 on page 24Fig. 15 on page 25 It is considered as a true aneurism the one which 3 vascular layers are involved in: fusiform morphology. A) A) Unenhanced CT : - Discontinuity of intimal calcifications - hyperdense areas in the thrombosed aneurysm site Page 11 of 40

12 - pleural or pericardial effusion with high density. B) B) Contrast CT: - active extravasation of contrast Page 12 of 40

13 Images for this section: Fig. 2 Multidetector CT of Aortic Dissection: A Pictorial Review.Radigraphics 2010 Page 13 of 40

14 Fig. 3 Disección de Aorta. Servicio de Cirugía Cardiaca Hospital General Universitario Gregorio Marañón, 2007 Page 14 of 40

15 Fig. 4: Coronal MPR: Complete AD Page 15 of 40

16 Fig. 5: Coronal MPR. Complete AD (red arrow) with linear intimal flap (blue arrow). The main infradiaphragmatic vessels (celiac trunk, superior mesenteric artery and right renal artery (yellow arrow) depend on the smaller lumen, which seems to correspond to the true light, and left renal artery (green arrow) arises from the larger aortic lumen, which seems to correspond to the false lumen. Page 16 of 40

17 Fig. 6: Coronal MPR: AD type A, with intimal flap (pink arrow). Page 17 of 40

18 Fig. 7: Coronal MPR:AD type A from the aortic root. Thrombosed right brachiocephalic (red arrow) and patent left subclavian artery (blue arrow) and common carotid artery (green arrow) Page 18 of 40

19 Fig. 8: Coronal MPR: Complete AD extends brachiocephalic trunk. Page 19 of 40

20 Fig. 9: RX: widening of the upper mediastinum (Red Arrow) with displacement of the trachea to the right (blue arrow) and left bronchus down (yellow arrow), consistent with aortic aneurysm appears to affect posterior margin of aortic arch Page 20 of 40

21 Fig. 10: Sagittal MPR: Ascending Aorta 41mm, possibly secondary to hypertension, identifying Ao descending aneurysm (red arrow) distal to the origin of the supra-aortic trunks(aneurysm type B) with 87 mm in the posterior aortic arch. Page 21 of 40

22 Fig. 11 Page 22 of 40

23 Fig. 12: RX: Aneurysm of aorta infra-renal broken into retroperitoneum, with active bleeding and large retroperitoneal haematoma layered pastry (red arrows) content Page 23 of 40

24 Fig. 13: Sagittal MPR: infrarenal aortic aneurysm (yellow arrow) with a cranio-caudal diameter of 12.6 cm. Around aortic aneurysm and occupying all the retroperitoneal, it s seen a great haematoma layered pastry (red arrow) without associated intraperitoneal free fluid Page 24 of 40

25 Fig. 14: Coronal MPR: Infrarenal aortic aneurysm (yellow arrow) and neck of the aneurysm 1mm. The aneurysm shows a transverse diameter of 94mm with extensive mural thrombus and a light of 59 x 46mm with the departure of the iliac arteries (green arrow) in the right anterolateral aspect of the lower portion of the aneurysm. Around aortic aneurysm and occupying all the retroperitoneal, it s seen a great haematoma layered pastry (red arrow) without associated intraperitoneal free fluid Page 25 of 40

26 Fig. 15: Axial slices: Aortic aneurysm infrarenal, broken into retroperitoneum with active bleeding (blue arrow) and large haematoma retroperoneal content (red arrows) without evidence of bleeding into peritoneal cavity Page 26 of 40

27 Fig. 16: Axial slices: PAU in descending thoracic aorta (red arrow) approx (3.5 mm), identifying passage of contrast (blue arrow) to the wall causing subintimal haematoma (green arrow) and pleural effusion (yellow arrow). Page 27 of 40

28 Fig. 17: Sagittal MPR: aneurysmal dilatation of the aortic arch up to 6 cm in diameter with descending aorta of about 4 cm. Subintimal haematoma (green arrow), pleural effusion (yellow arrow). No signs of aortic dissection is appreciated. Page 28 of 40

29 Fig. 18: Coronal MPR. Aortic dissection extending from the origin of the Left Subclavian (yellow arrow) to the descending thoracic aortic (Red Arrow) (Stanford B). Page 29 of 40

30 Fig. 19: Sagittal MPR. Aortic dissection extending from the origin of the Left Subclavian (yellow arrow) to the descending thoracic aortic (Red Arrow) (Stanford B). Page 30 of 40

31 Fig. 20: Coronal MPR: AD type B. Page 31 of 40

32 Fig. 21: Axial slices. Stanford type B AD with acute point of contrast extravasation into the false lumen (red arrow). Pericardial effusion (Green Arrow). Page 32 of 40

33 Fig. 22: Sagittal MPR. Stanford type B AD, from beginin of left subclavian to the common iliac. The point of intimal dissection is located approx 3 cm Left subclavian in the left side margin, where a sharp contrast extravasation (red arrow) to the false lumen is recognized. Page 33 of 40

34 Fig. 23: Axial slice: asymmetric and concentric thickening of the ascending thoracic aortic wall (middle and distal segment) in relation to aortic intramural haematoma (yellow arrow) associated with a small intimal ulcer (red arrow) in posterior aspect of distal ascending thoracic aorta. No intimal flap is appreciated. Page 34 of 40

35 Fig. 24: Axial slice: asymmetric and concentric thickening of the ascending thoracic aortic wall (middle and distal segment) in relation to aortic intramural haematoma (yellow arrow) associated with small intimal ulcer (red arrow) in posterior aspect of distal ascending thoracic aorta. No intimal flap is appreciated. Page 35 of 40

36 Fig. 25: Axial slice: peripheral intimal calcification. Page 36 of 40

37 Findings and procedure details The presenting clinical signs and symptoms of AAS of any etiology are usually indistinguishable. Although typical cases demostrate characteristic imaging features of each disease, imaging findings may also overlap between different entities, especially when the process is dynamic and evolving. Thanks to multidetector-row CT the detectability of some pathognomonic findings such as the primary intimal tear in trombosed AD or ulcerative plaque in PAU makes easy diagnostic of AAS and allows to orient management. Therapeutic alternatives in the management of AAS Fig. 26 on page 38 encompass conservative medical treatment (whose goals include controlling pain, hypertension and left ventricular ejection fraction, where possible or patient's condition prevents surgery), and surgical options within the interventional radiology which looks set to play an important role Report of AAS includes: 1. Description of injury: location and type A or B, morphology, size, relationship to other adjacent vessels, 2. Calibrate the aorta proximal and distal to the lesion, 3. Possible anatomical variables or 4. Associated complications (such as involvement of the coronary arteries (causing acute coronary syndromes), extent of involvement the valve plane (which can cause aortic insufficiency), engagement of the branches of the aorta (thoracic organ hypoperfusion or extrathoracic) aortic rupture (with hemopericardio, hemothorax and / or secondary hemomediastinum)... Page 37 of 40

38 Images for this section: Fig. 26 Disección de Aorta. Servicio de Cirugía Cardiaca Hospital General Universitario Gregorio Marañón, 2007 Page 38 of 40

39 Conclusion The radiologist should know and provide an accurate and detailed AAS diagnosis, to guide treatment (conservative or interventional) because this entity has high mortality, and require urgent management. Page 39 of 40

40 References 1.Natural History and CT Appearances of Aortic Intramural Hematoma. Christine P. Chao, MD T. Gregory Walker, MD Sanjeeva P. Kalva, MD RadioGraphics 2009; 29: Multidetector CT of Aortic Dissection: A Pictorial Review. Michelle A. McMahon, FRCR Christopher A. Squirrell, FRCR. RadioGraphics 2010; 30: Multidetector CT of Thoracic Aortic Aneurysms. Prachi P. Agarwal, MD Aamer Chughtai, MD Frederick R. K. Matzinger, MD Ella A. Kazerooni, MD, MS RadioGraphics 2009; 29: Penetrating Atherosclerotic Ulcer of the Aorta: Imaging Features and Disease Concept. Hideyuki Hayashi, MD Yohjiro Matsuoka, MD Ichiro Sakamoto, MD Eijun Sueyoshi, MD Tomoaki Okimoto, MD Kuniaki Hayashi, MD Naofumi Matsunaga, MD RadioGraphics 2000; 20: Thoracic Aorta - the Acute Aortic Syndrome. Ferco Berger, Robin Smithuis, Otto van Delden. The Radiology Assistant. 6. Guías de práctica clínica de la Sociedad Española de Cardiología en enfermedades de la aorta José Luis Zamorano (coordinador), Juan Mayordomo, Arturo Evangelista, José Alberto San Román, Camino Bañuelos y Manuel Gil Aguado. Rev Esp Cardiol 2000; 53: Page 40 of 40