Can signal intensity of the continuous wave doppler regurgitant jet estimate severity of mitral regurgitation

Abstract Visual estimates of the intensity of the continuous wave (CW) Doppler regurgitant jet signal have been used to estimate the severity of valvular regurgitation. Theoretically, the strength of the reflected Doppler signal is a function of the number of scatterers. To test this approach quantitatively, free jets were produced in 27 experiments using a power injector and cornstarch suspension varying in concentration from 1% to 3%. Flow volume was varied from 5 to 15 ml, and orifice diameter varied from 2.5 to 10 mm. Machine settings were kept constant. Also, 22 patients with mitral regurgitation (MR)—5 mild, 11 moderate, and 6 severe by angiography—were studied. Average signal intensity under the CW Doppier flow curve was calculated using a computer image processor. In MR patients, average regurgitant flow (RF) intensity was compared with average mitral forward flow (FF) signal intensity. (1) The intensity under the CW flow signal in the free jet experiments correlated well with injection volume ( r > 0.98). (2) RF average signal intensity did not correlate with angiographic MR severity ( r = 0.21), but the ratio of RF to FF average signal intensity did correlate with MR severity ( r = 0.73). (3) The sensitivity and the specificity of an RF/FF ratio > 0.65 for angiographically severe mitral regurgitation were both 83%. (4) The sensitivity and specificity of an RF/FF ratio