Purpose: Calcification is an independent predictor of mortality in aortic valve stenosis (AS). Currently computed tomography (CT)-derived calcium score is used to quantify aortic valve (AV) calcifications. However, CT is an ionizing technique and other non-invasive modalities are warranted. Echocardiographic calibrated integrated backscatter (cIB) is a promising technique for quantifying AV calcification. We aimed to validate cIB for measuring the amount of calcium in an in-vitro model. Methods: Six different amounts of CaCl2 95% powder (0, 2.5, 5, 10, 20 and 30 mg) were mounted on sample slides. Each amount of CaCl2 was homogeneously spread on 5 different circle-shaped surfaces (20, 40, 60, 120 and 200 mm2) to obtain different calcium densities.The CaCl2 was glued with Pattex® 100% transparent onto the sample slide. The sample slides were put in a recipient, filled with water and echocardiographic images were obtained with a 10 MHz probe. For each amount of Cacl2, cIB values were measured in a region of interest (ROI) equal to the size of the shaped surface, and the correlation to the calcium amount and density were calculated. Results: There was a significant correlation between calcium amount and cIB-value (r2=0.8, p <0.0001). The cIB-value ranges between 20 decibels (dB) for the samples without calcium and 48dB for the heavily calcified samples. The calcium density, expressed as calcium amount/surface, has an exponential correlation with cIB (r2=0.624). cIB-values reach a plateau, where further increase in calcium density has no influence on the cIB measurements. By measuring cIB-value, it was possible to calculate the calcium density using the formula: Y=6.793E-007*exp(0.295*X), with Y=calcium density and X= cIB-value. Conclusion: This pre-clinical study showed a strong correlation between cIB-measurements and Ca amount in an in-vitro model. Moreover, the cIB measurement allowed to calculate the Ca density. The product of the area of calcifications and Ca density represents the Ca amount per ROI. These two parameters should enable to quantify more precisely the calcifications at the level of AV using cIB.
|Publication status||Published - 4 Dec 2014|
|Event||18th Annual Meeting of the European Association of Cardiovascular Imaging (Euro Echo Imaging 2014) - Vienna, Austria|
Duration: 3 Dec 2014 → 6 Dec 2014
|Conference||18th Annual Meeting of the European Association of Cardiovascular Imaging (Euro Echo Imaging 2014)|
|Period||3/12/14 → 6/12/14|