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Aortic Aneurysm following Valve ReplacementFollow-up exams such as ultrasounds can be used to determine the presence of certain abnormalities, but can be limited in their diagnostic capability. Prospective cardiac CT allows to have a complete anatomical assessment of the coronaries and the aorta at very low dose. |
Courtesy of Dr. J.L Sablayrolles, Centre Cardiologique du Nord, Saint-Denis, France
The Centre Cardiologique du Nord (CCN) was founded in 1973 by a consortium of cardiologists and established in Saint-Denis, 3 km north of Paris. Its specialty, as can be taken by its name, are cardiovascular pathologies. With more than 180 beds and over 1000 cardiac interventions per year, it is renowned as a center of excellence in the diagnosis and treatment of cardiovascular illnesses.
The Radiology Service has been active in the cardiac CT scanning field since the year 2000, having used a LightSpeed VCT and a LightSpeed VCT XT scanner to perform these exams. More recently, their cardiac CT-scanning activity has been passed on to the their newly acquired Discovery™ CT750HD, with more than 800 cardiac scans in 4 months of activity.
Patient History
The patient, a 74-year-old man, underwent an aortic valve replacement through the use of the Bentall procedure. A follow-up ultrasound exam showed an abnormal form in proximity to the aorta.
A cardiac CT was performed in order to determine its detailed morphology.
Technique
The cardiac CT exam was performed on the Discovery CT750HD. High definition cardiac mode with ASIR image reconstruction in prospective ECG-gating were used for acquisition of the complete thoracic aorta (24 cm coverage).
The heart rate was 55 BPM and the resulting dose was estimated to be 3.6 mSv* (209 mGy.cm**).
The contrast injection was biphasic, using 90 mL of Omnipaque 350 and 50 mL of saline solution, both injected at 5 mL/s.
* Dose conversion obtained from EUR-16262 EN with chest factor of DLP*0.017** Dose based on phantom estimates of a prospective ECG-gated acquisition with 10 ms padding
Findings
An aneurysm of the thoracic aorta was found 13 mm above the aortic valve. The aneurysm itself is located upon the reimplanted ostium of the RCA. The remainder of the aorta was normal in all aspects.
An analysis of the patient’s coronary arteries highlighted a significant stenosis of the RCA’s ostium (estimated between 70-90%).
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Conclusion
Due to the RCA’s significant ostial stenosis, a venal bypass was put in place between the aorta and segment II of the RCA.
With the Discovery CT750HD’s SnapShot Pulse technology and ASIR reconstruction, a full thoracic aorta and coronaries were studied at only 3.6 mSv**. This allows for routine acquisitions of full aortas under 5 mSv.
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