SOMATOM Definition Flash provides the entire extension of aortic dissection in 2 seconds scan time
SOMATOM Definition Flash Scanning
Eva Hendrich* , Stefan Martinoff, MD* , Tanja Gassert**, Andreas Blaha**
*Department of Radiology and Nuclear Medicine, German Heart Center Munich, Germany
**Business Unit CT, Siemens Healthcare, Forchheim, Germany | 2009-04-21
A 62-year-old male patient with a known Type B aortic dissection affecting the entire descending and abdominal aorta was referred to the radiology department of the German Heart Center Munich for a follow-up examination after stenting of the right renal artery. Additionally, an actual vascular status was needed in preparation for implantation of a thoracic aortic stent. The examination was done with the new SOMATOM Definition Flash, utilizing ultrafast Flash spiral acquisition made possible by 2 X-ray tubes simultaneously collecting information. The actual scan time was only 2 seconds.
Aortic dissection originates closely distal to the ostium of the left subclavian artery. The true lumen of the descending thoracic aorta is very narrow and comprises only about 1/3 of the aortic lumen. The cranial part of the false lumen shows a good contrast-enhancement. The worse contrast-enhanced caudal part of the false lumen indicates a low blood flow und thus predisposition to thrombosis in the false lumen. The coeliac trunk, the superior mesenteric artery and both renal arteries are feed by a very small sickle shaped true lumen of the abdominal aorta.
By contrast the inferior mesenteric artery originates from the barely perfused false lumen, therefore its proximal part is not contrast-enhanced. The distal part however is well collateralized over Riolan´s anastomosis.
The dissection ends 2 cm above aortic bifurcation.
Due to the acquisition time of only 2 seconds for thorax and abdomen, it was possible to freeze the motion of the coronary arteries. The coronary arteries show significant calcifications, especially in the proximal part of the right coronary artery (RCA).
Due to the lack of distance between the cranial end of the aortic dissection and the ostium of the left subclavian artery, it will be difficult to place an aortic stent.
subclavian artery, it will be difficult to place an aortic stent. The relation of true and false lumen of this type B dissection was quickly and accurately displayed. Due to the extremely fast scan time of only 2 seconds for 69 cm and highest temporal resolution of 75 msec, it was easily possible to freeze motion of the aortic arch.
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