It is often difficult to spot the ductus venosus among the numerous vessels in the fetal abdomen. I have devised an easy way out.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg-IPrGVcn4s-4zdjt6MTeTeZvo4xc-WONPoTJ1PH8khI_CyqogyGidyUKoa5TCqCVBxtrwnQbwW67Kk4Y3-owt6LQeIBfl3rOKZYWXTikDzhVzZQb5xbnmBml4NBDCKy_fKBTmN5bNaHym/s320/ductus-ven-normal-1a.jpg)
a) First spot the umbilical vein passing through the fetal abdomen.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnhaMgzUZpG1Jiqw2elxUcvrVTBzGSjwkmwEEdrR85KstrWc0-WIKR90P_yQMI9SjOZLYUTIKhYEsKa5aet-Xur16Sme5T_8lfRiqprwYzaw5g6AdQQ4vhxIHvDOshBoKgBDz2YAVGJzzB/s320/ductus-ven-normal-1b.jpg)
b) Switch on the color Doppler function to view the flow of the umbilical vein.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgz-I9el8qQqrFbAOAlhM04RSAF_0-m-86HOcWG6EqcQcBPFXUdYZWI9DSbnTDWMyOy6UEjotMREtl3O6oZIIF7XETUoDOZGrEKG7qFrCHlfcAKPhPmhZbSpQKHeB0w-KeVxUENXvcg7Kws/s320/ductus-ven-normal-1c.jpg)
c) Reduce or increase the PRF (pulse repetition frequency) function of the color flow until you spot a prominent but short vessel with MARKED ALIASING (ie: turbulent flow producing a multiple shades in the flow image). This is most likely to be the ductus venosus. Note the location of the vessel, just anterior to the fetal aorta.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmplb51u_M2ZVAP0S9Iz3cyXhs0drgIAU3RKDA5Q018BW6974VjMcH3bPA7OOOxo9ZaQKq_qUMbb9cprotsCY0P5LFzw8mkBJ71aDYJTDde3yhvWF0P6Ozw0-A-HJ_jS56xPZgd_JH3_WM/s320/ductus-ven-normal-1d.jpg)
d) Now switch on the spectral doppler trace of the vessel. This will give a wavy spectral waveform with 3 waves (d): The S wave, the D wave and the A wave. Note the marked diastolic flow in this waveform. This is diagnostic of a normal Ductus venosus. All images by Joe Antony, MD, using a Toshiba Nemio -XG ultrasound system.
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