Number 09-13 Severe AI in a bicuspid AV assessed with CMR
Case from: Gerasimon G, York G, Steel K. Cardiovascular Imaging Center of Excellence, San Antonio Military Medical Center, San Antonio, Texas, U.S.A
Clinical history: 43 year old woman with Turner's syndrome referred for evaluation of NYHA II dyspnoea and palpitations. Transthoracic echocardiography was performed to investigate a holo diastolic murmur and confirmed moderate to severe AI and a bicuspid AV. CMR was requested to confirm the diagnosis and to further evaluate the AI severity and aortic dimensions.
Parasternal SA echocardiogram with colour Parasternal LVOT echocardiogram with colour
The echo images demonstrate a clear eccentric jet of at least moderate aortic regurgitation.
Movie 1 Movie 2
Movie 3 Movie 4
The SSFP LVOT cine image (Movie 1) shows tickened aortic valve leaflets, turbolent flow across the AV and an eccentric regurgitant jet directed towards the septum.
Part of this jet is also visualized in the basal short-axis cine (Movie 2).
Selective cine of the aortic valve (Movie 3) confirms bicuspid aortic valve. A through-plane flow image of the corresponding plane was also acquired (Movie 4).
Movie 5 Movie 6
Movie 5 is a cine SSFP oblique sagital view of the aorta. This image allows all relevent dimensions and measurements to be performed. The ascending aorta up to the proximal aortic arch is dilated. In addition, a clear diastolic flow reversal is noted in the ascending and descending aorta, confirming severe aortic regurgitation (ref 1).
For comparison, Movie 6 represents an oblique sagittal view of a normal aorta.
Flow Analysis in the Ascending (left) and Descending Aorta (right) Demonstrating Diastolic Flor Reversal
Flow mapping confirmed regurgitant severity and the severity of the regurgitation.
From the through plane flow images, the calculated aortic forward flow was 126cc, regurgitant flow 85cc, and the calculated regurgitant fraction was 67%.
In the absence of additional valvular abnormaliities, LV/RV stroke volumes difference can also provided an accurate evaluation of regurgitation fraction. In fact, LV stroke volume calculated from the short-axis cine was 144cc and the RV stroke volume 44cc. The calculated regurgitant fraction was 69%.
Perspective: This is a useful case to demonstrate the role of CMR in providing a complete evaluation of the aortic valve and aorta in a patient with Turner syndrome and severe AI (ref 2-5). Accurate imaging and measurement of the aortic root, and ascending aorta is of key importance to guide surgical intervention.
Although echocardiography remains the gold standard in assessing valvular heart diseases, CMR has the potential to delineate the anatomy of the aortic valve, expecially in cases where transthoracic echocardiography is limited by poor acustic window. However, this is an issue that can also be overcomed by TEE. Of note, the quality of inplane and through plane flow acquisitions (appropriate image plane, and adequate VENC) play a major role in determining riable flow measurements by CMR. Also, higher velocities tend to be underestimated by CMR. CMR and echocardiography are complentary imaging techniques in patients with valvular heart disease.
Bicuspid aortic valves are frequently associated withsignificant abnormalities of the aorta (ref 6).Diverse histological characteristics and abnormal elasticity of the ascending aortahave been reported to belikely determinants of aortic dilatation and, possibly, dissectionin patients with bicuspid aortic valve (ref 7-9).
1.Sutton DC, Kluger R, Ahmed SU, Reimold SC, Mark JB. Flow reversal in the descending aorta: a guide to intraoperative assessment of aortic regurgitation with transesophageal echocardiography.J Thorac Cardiovasc Surg. 1994;108:576-82.
3. Ho VB, Bakalov VK, Cooley M, et al. Major vascular anomalies in Turner syndrome: prevalence and magnetic resonance angiographic features. Circulation 2004;110:1694-1700.
4. Ostberg JE, Brookes JA, McCarthy C, et al. A comparison of echocardiography and magnetic resonance imaging in cardiovascular screening of adults with Turner syndrome. J Clin Endocrin Metab 2004;89:5966-5971.
5. Chalard F, Ferey S, Teinturier C, et al. Aortic dilatation in Turner syndrome: the role of MRI in early recognition. Pediatr Radiol 2005;35:323-326.