Incidental Aortic Valve Calcification on CT Scans: Significance for Bicuspid and Tricuspid Valve Disease Michael D. Hope, MD, Thomas H. Urbania, MD, John-Paul J. Yu, MD, PhD, Sam Chitsaz, MD, Elaine Tseng, MD Rationale and Objectives: The aim of this study was to evaluate the role of incidental aortic valve calcification on routine computed tomographic scans as a marker for stenosis, as assessed by echocardiography, in patients with bicuspid aortic valve (BAV) and tricuspid aortic valve. Materials and Methods: Computed tomographic and echocardiographic studies were retrospectively reviewed for 182 consecutive, unselected patients and 426 patients identified by a record search for ‘‘aortic valve calcification.’’ Location and severity of valve calcifica- tion were correlated with aortic valve morphology and stenosis. Differences between subgroups were assessed using c 2 or Fisher’s exact tests. Results: In unselected patients, calcification was present in 25.8% with tricuspid aortic valves (46 of 178) and 75% (three of four) with BAV. In patients selected for valve calcification, the average age of those with tricuspid aortic valves (n = 395) was 14.3 years older than those with BAV (n = 31). Patients with BAV were more likely to have severe calcification (87% vs 50%, P < .001), and if severe calcification was present, it was more likely to involve only the valve leaflets (41% vs 9%, P < .001) and result in aortic stenosis (85% vs 58%, P = .006). Patients aged < 60 years with severe calcification were more likely to have BAV (56% vs 7%; odds ratio, 7.9; 95% confidence interval, 3.4–18.7). Conclusions: Aortic valve calcification was found 14 years earlier in patients with BAV and was more severe and strongly linked to aortic stenosis. Valve calcification on computed tomographic scans should be considered a marker for BAV if found before the seventh decade. Key Words: Bicuspid aortic valve; aortic stenosis; aortic valve calcification. ªAUR, 2012 A ortic valve calcification identified on computed tomographic (CT) scans has been studied as a marker for stenosis of tricuspid aortic valve (TAV), but its significance for bicuspid aortic valve (BAV) is not well established. In studies principally of TAV, the severity of valve calcification as assessed by qualitative and quantitative CT methods correlates with increased degree of aortic stenosis (1–3). Marked valve calcification predicts adverse clinical outcomes. Older studies with other imaging modalities have demonstrated a clear link between increased degree of aortic valve calcification and the progression of aortic stenosis, need for aortic valve replacement, and death (4,5). Minor aortic valve calcification, however, is a common finding on multi–detector row computed tomography that is often hemodynamically insignificant (6). Whether these findings apply to BAV disease as well has not been studied directly. BAV is relatively common (1%–2% of the population) and progresses to aortic stenosis in the majority of patients (7). Nearly half of isolated aortic valve replacements for aortic stenosis are attributed to BAV (8). Because aortic stenosis develops rapidly and is seen 10 to 15 years earlier than in patients with TAV (9,10), improving the early detection of BAV by imaging before advanced aortic valve disease ensues could significantly aid the clinical management of these patients. Aortic valve calcification is an attractive marker for BAV. Not only is it a common incidental finding on CT scans that is easily interpreted by radiologists, but also it is seen at younger ages with BAV than with TAV. Advanced aortic valve calcification has been reported with BAV in patients aged < 30 years and with 100% incidence by the seventh decade (11,12). In this study, we sought to compare the role of incidental aortic valve calcification on CT scans as a marker for aortic stenosis in patients with TAVand BAV. With a simple grading system for aortic valve calcification, we hoped to establish criteria for the identification of patients with BAV and aortic stenosis, including an age cutoff below which the likelihood of BAV is significantly elevated. Acad Radiol 2012; 19:542–547 From the Department of Radiology, University of California, San Francisco, 505 Parnassus Avenue, Box 0628, San Francisco, CA 94143-0628 (M.D.H., T.H.U., J.-P.J.Y.); and the Department of Cardiothoracic Surgery, San Francisco Veterans Affairs Medical Center, San Francisco, CA (S.C., E.T.). Received August 15, 2011; accepted October 4, 2011. Address correspon- dence to: M.D.H. e-mail: michael.hope@ucsf.edu ªAUR, 2012 doi:10.1016/j.acra.2011.10.012 542