Friday, August 20, 2010

Color Doppler ultrasound videos of 3rd trimester pregnancy:

Color Doppler ultrasound is an essential part of the imaging or ultrasound scan of the fetus, even in the 3rd trimester. the basic Doppler imaging of the fetus includes study of the fetal MCA or middle cerebral artery, the fetal ductus venosus and the umbilical artery. Of these, Doppler imaging of the ductus venosus is the most difficult. Here we have some normal Triplex Doppler videos of these 3 main vessels of interest to the sonographer or radiologist. All the Color Doppler videos below show video and accompanying audio.
Color Doppler and spectral waveform of the fetal middle cerebral artery:
Here is the second video of the MCA:
video                                                                             This Color Doppler video clip demonstrates the exact location of the middle cerebral artery (arrow) among the major vessels of the fetal brain.  
Yet another demonstration of the fetal middle cerebral artery (arrow pointing at the vessel) :
video Due to fetal head movement and respiratory movements the arrow points slightly lower than the actual position of the fetal MCA.

                      Note the high velocity, high resistance flow in this normal fetal middle cerebral artery, with almost no diastolic flow that is very striking about this artery.
 The other important fetal vessel that is studied here is the umbilical artery. This spectral Color Doppler waveform video clip shows the normal umbilical artery. The normal umbilical artery shows low resistance flow with high diastolic velocity, which is the opposite of what is seen in the fetal MCA.                                                                                                           
video                                                                                 The next vessel to be studied in this normal fetus is the most elusive as we mentioned earlier and is the fetal ductus venosus. This color Doppler video /spectral waveform shows the normal ductus venosus with low resistance flow with typically 3 waves seen in spectral display- the S, D and A waves. This vessel is short and disappears from view unless the clinician has a steady hand on the probe and both mother and fetus cooperate.                                                                                                                                                     

video                                                                              Here is another attempt at the normal ductus venosus in this 3rd trimester fetus:
       video                                                                     The Nemio-XG ultrasound machine which I have used for this study has an "update" button which helps to fine tune the spectral video display. This update button has been activated to the later half of this ductus           venosus video. The result is obvious, as the waves become smaller and more coherent.                                    video                                                                   Note the almost M-shape of these normal ductus venosus waves. For more on this topic visit:                               for more images and case studies of abnormal fetal doppler.                 
Here is yet another spectral Doppler video tracing of a 34 week old fetus (another case):    video 
Often, this short vessel slips out of view due to fetal movements or maternal breathing. Hence a lot of effort is needed to get optimal color Doppler spectral tracing of fetal ductus venosus.


Saturday, August 14, 2010

Gall bladder sludge- ultrasound video clip:

video This B-mode ultrasound video clip shows what is called as limy bile in the gallbladder. This organ, though distended, shows echogenic particles and also calculi (stones) of 4 to 6 mm. in its lumen. See this page for more: 

The bile in the gallbladder must be a rather thick fluid, almost jelly or putty like in consistency, given that the ultrasound video clip shows almost no motion of the debris in the gallbladder. The overall appearance and echogenicity of the gall bladder is similar to that of the liver, an appearance called hepatization.

Friday, August 13, 2010

Color Doppler ultrasound video of a ureteric jet:

This short Color Doppler video clip shows a jet of urine (red stream) emerging from the left ureteral orifice and sprayed into the distended urinary bladder. The jet of urine was normal in this patient. A normal urine jet from the ureter is an indication that there is no obstruction in the ureter of that side, at least not at the level of the ureteric orifice.

Wednesday, August 11, 2010

Extrarenal pelvis:

This adult patient shows a ballooning of the pelvis (P) of the left kidney (see ultrasound images above). A major portion of the renal pelvis lies outside the renal sinus, a condition called extrarenal pelvis. The transverse section image (lower image), brings out the lesion clearly. The extrarenal pelvis is a normal variant and needs no specific treatment. However, in this case, the calyces of the left kidney show mild ballooning suggesting obstructive changes which require further radiological study.

Sunday, August 01, 2010

Solitary cyst of fetal kidney:

This 2nd trimester fetus shows a solitary cyst of the lower pole of left fetal kidney. The cyst is small (6 mm.) with no internal debris or septae. The fetal renal cyst shows no communication withe the pelvicalyces which appear norma, thus ruling out fetal hydronephrosis. The fetal urinary bladder (BL) appears normal. The above ultrasound images are typical of uncomplicated cyst of the fetal left kidney. The important differential diagnoses in this case include renal abscess or renal hematoma, both of which seem improbable here. The other possibility is that this cyst is precursor to onset of autosomal dominant polycystic kidney disease (adult type). Polycystic kidney disease may develop in this baby during adult life. Both images are courtesy of        Dr. Ravi Kadasne, MD, UAE.
For more on this topic visit: