Hostname: page-component-586b7cd67f-t7czq Total loading time: 0 Render date: 2024-11-28T09:48:08.928Z Has data issue: false hasContentIssue false

Commentary specifically on the article by S. Harling et al

Published online by Cambridge University Press:  05 March 2013

Thieu Nguyen*
Affiliation:
All Children's Hospital, Pediatric CardiologyOutpatient Care CentreSt. Petersburg, United States
Rights & Permissions [Opens in a new window]

Abstract

Type
Letter to the Editor
Copyright
Copyright © Cambridge University Press 2013 

Dear Editor,

Quantification of left-to-right shunting through a patent ductus arteriosus by colour Doppler is an interesting idea, but I am not quite convinced that the technique as outlined in the paper by Harling SReference Harling, Jansson, El-Segaier and Peronen 1 can be a reliable tool in an in vivo setting; I am aware that flow can be accurately determined by colour Doppler.Reference Tadashi and Richard 2 , Reference Landwehr, Schindler, Heinrich, Dölken, Krahe and Lackner 3 However, these studies were carried out in controlled settings (in vitro) in which the sizes, shapes, and actual velocities of the streams were known. The size of the jet, its temporal resolution, and extent of aliasing velocities can be significantly affected by the angle of Doppler interrogation, transducer frequency, and instrument settings such as gain, output power, Nyquist limit, size, and depth of the image.Reference Stewart, Cohen and Salcedo 4 In in vivo settings, these variables vary with each patient and are highly operator dependent, which ultimately may have a negative impact on the reproducibility and accuracy of quantitative estimation. In addition, assessing the degree of shunting based on a single two-dimensional still frame can be misleading. The jets of ductal artery can be central or eccentric (wall hugging) and the sizes of the jets may vary significantly depending on the planes of interrogation. The wall-impinging jets are significantly smaller than centrally directed jets of similar haemodynamic severity, mainly because they flatten out on the wall of the main pulmonary artery. To fully appreciate the severity of shunting, one needs to examine the patent ductus arteriosus by colour Doppler in multiple sweeping planes and windows.

References

1. Harling, S, Jansson, T, El-Segaier, M, Peronen, E. Quantification of left-to-right shunt through patent ductus arteriosus by colour Doppler in children admitted for device closure. Cardiol Young 2012; 22: 5762.Google Scholar
2. Tadashi, T, Richard, SCC. Quantitative study of steady flow using color Doppler ultrasound. Ultrasound Med Biol 1991; 17: 595605.Google Scholar
3. Landwehr, P, Schindler, R, Heinrich, U, Dölken, W, Krahe, T, Lackner, K. Quantification of vascular stenosis with color Doppler flow imaging: in vitro investigations. Radiology 1991; 178: 701704.Google Scholar
4. Stewart, WJ, Cohen, GI, Salcedo, EE. Doppler color flow image size: dependence on instrument settings. Echocadiography 1991; 8: 319327.Google Scholar