Followup

The value of MRI in the follow-up of patients with surgically corrected or conservatively treated aortic dissection has been well established. The long-term prognosis of patients with aortic dissection is determined by the development of complications. Rupture of the aorta after development of a secondary aneurysm is the most common cause of late death. Other causes are the development of severe aortic insufficiency or malfunction of a prosthetic valve18.

Figure 6.6. Images of a patient with a penetrating aortic ulcer in the descending aorta. The patient presented with abdominal pain and fever. Blood cultures grew salmonella species. White arrows: penetrating ulcer. Black arrows: surrounding hematoma. A: MRI image, SSFP sequence, oblique coronal plane. B: MRI image, SSFP sequence, transverse plane. C: Oblique sagittal MRI image, contrast-enhanced. D: Oblique sagittal MRI image, contrast-enhanced 3D reconstruction, maximal intensity projection (MIP) reconstruction.

Figure 6.6. Images of a patient with a penetrating aortic ulcer in the descending aorta. The patient presented with abdominal pain and fever. Blood cultures grew salmonella species. White arrows: penetrating ulcer. Black arrows: surrounding hematoma. A: MRI image, SSFP sequence, oblique coronal plane. B: MRI image, SSFP sequence, transverse plane. C: Oblique sagittal MRI image, contrast-enhanced. D: Oblique sagittal MRI image, contrast-enhanced 3D reconstruction, maximal intensity projection (MIP) reconstruction.

Therefore, regular follow-up examinations are necessary, and the Task Force on Aortic dissection of the European Society of Cardiology recommended MRI as the best tool to provide serial information in operated and conservatively treated patients18. MRI provides a comprehensive evaluation of the entire aorta with all important aspects of the disease. Assessment of progressive thrombosis and residual flow in the false lumen is possible25. Serial exact and highly reproducible documentation of aortic diameter perpendicular to aortic lumen can be accomplished. Incompetent aortic valves can be identified by cine imaging. Phase-contrast flow measurements allow the quantification of aortic regurgitation. As compared to serial echocardiography (usually TEE), it is much more convenient an accurate to compare serial MRI examinations

Figure 6.7. Images of the same patient as in Figure 6.6. A: CT image, transverse plane. White arrows: ulcer. Black arrow: calcification adjacent to the ulceration. B: CT image, transverse plane postcontrast. C: Angiography. D: Angiography after implantation of an endoprosthesis. C and D courtesy of H. Schumacher, MD, University of Heidelberg, Department of Vascular Surgery.

Figure 6.7. Images of the same patient as in Figure 6.6. A: CT image, transverse plane. White arrows: ulcer. Black arrow: calcification adjacent to the ulceration. B: CT image, transverse plane postcontrast. C: Angiography. D: Angiography after implantation of an endoprosthesis. C and D courtesy of H. Schumacher, MD, University of Heidelberg, Department of Vascular Surgery.

as they provide a complete 3D set of aortic anatomy and related structures facilitating quantitative comparisons.

Detailed knowledge of surgical technique and its anatomical consequences are essential for accurately evaluating postoperative imaging. Abnormal soft tissue is occasionally demonstrated outside a graft or anastomosis. The anatomical relationships can usually be explained once surgical details are known26. Late complications following surgery for aortic dissection are frequently related to the anastomosis or the aortic arch and its side branches. MRI is better suited to depict the anastomoses (Figures 6.8 and 6.9) and neck vessels27 and may thus be preferable to TTE/TEE for serial evaluation of post-surgical patients with type I dissection.

MRI also lacks the disadvantages of CT such as radiation and nephrotoxic contrast material.

Figure 6.8. MRI images of a patient with multiple aortic operations. The patient had a type A aortic dissection. A hemiarch was implanted. A few years the descending aorta dilated and was replaced. The right subclavian artery is dilated. A: SSFP sequence, sagittal oblique plane shows the anastomoses in the ascending and in the descending aorta (white arrows). B: Surface reconstruction of a contrast-enhanced 3D angiography. Anastomoses in the ascending and in the descending aorta (white arrows).

Figure 6.8. MRI images of a patient with multiple aortic operations. The patient had a type A aortic dissection. A hemiarch was implanted. A few years the descending aorta dilated and was replaced. The right subclavian artery is dilated. A: SSFP sequence, sagittal oblique plane shows the anastomoses in the ascending and in the descending aorta (white arrows). B: Surface reconstruction of a contrast-enhanced 3D angiography. Anastomoses in the ascending and in the descending aorta (white arrows).

Figure 6.9. MRI images of a patient 5 days after an operation for type A aortic dissection with aortic valve replacement and conduit. A: Transverse plane. Around the ascending aorta a circular structure can be seen. This represents periaortic hematoma (white arrow). B: Sagittal oblique plane shows the two anastomoses in the ascending aorta (white arrows) and the remaining dissection in the descending aorta. C: Bileaflet aortic valve opens normally in systole (black arrow).

Figure 6.9. MRI images of a patient 5 days after an operation for type A aortic dissection with aortic valve replacement and conduit. A: Transverse plane. Around the ascending aorta a circular structure can be seen. This represents periaortic hematoma (white arrow). B: Sagittal oblique plane shows the two anastomoses in the ascending aorta (white arrows) and the remaining dissection in the descending aorta. C: Bileaflet aortic valve opens normally in systole (black arrow).

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