Wednesday, June 29, 2011

Ultrasound imaging of normal deep veins

The normal deep veins of the lower limb- the femoral and popliteal veins are usually studied to rule out deep venous thrombosis. One of the various methods of ruling out clot formation (thrombosis) in the deep veins is the application of mild pressure with the ultrasound probe on the deep vein. This method is called compression and the method is called testing the compressibility of the deep vein.
This ultrasound video clip (above) shows the femoral vein (FEM V.) and the popliteal vein (POPL V.), after probe pressure is applied to determine whether complete collapse of the veins is possible. The end stage shows total apposition of the walls of the vein as pressure is applied. This confirms the absence of thrombus (clot) within the vein. This testing of the normal compressibility of the femoral and popliteal veins must be done along the full extent of the deep veins. As one goes downwards along the course of the femoral vein to the mid thigh, this may be difficult due to the femoral vein entering the adductor canal.
   At this stage the sonologist may try looking for normal augmentation of flow by pressure on the calf muscles. A sharp augmentation spike on spectral doppler trace means there is no thrombus along the course of the deep veins till the calf.
For more on this topic visit: color Doppler and ultrasound study of the deep veins of lower limb.

Saturday, June 18, 2011

Subendometrial or junctional zone contractions (endometrial peristalsis):

This transvaginal ultrasound video clip shows the changes that take place in the endometrium of the uterus, in the immediate post-ovulatory phase or days immediately after ovulation. This patient underwent medication for induction of ovulation. The first part of the ultrasound video clip shows the endometrium on day 1 after ovulation- the endometrial stripe shows early secretory changes. But this ultrasound video shows another more striking feature- slow but definite waves of peristalsis (contractions) in the endometrium  proceeding from the cervix of the uterus upwards to the fundus. These waves of contraction are called junctional zone contractions or subendometrial contractions. It is believed that these contractions help propel the sperms upwards in the uterine cavity to enable fertilization of the ovum.
  Junctional zone contractions or endometrial peristalsis is most obvious in the immediate post-ovulatory period and decrease after that. During menstruation too, subendometrial and uterine contractions help propel the blood and endometrial tissue downwards; here the peristalsis is from the fundus downwards.
References: 1) Google books description of endometrial peristalsis
2) Textbook of ultrasound (google books)- subendometrial contractions
3) article on junctional zone peristalsis- Ultrasound imaging

Thursday, June 2, 2011

Cystitis cystica- transrectal Ultrasound video

I uploaded this excellent demonstration of a small 5 mm. cyst in the submucosal region of the urinary bladder on youtube. I was intrigued by the appearance of this small bubble close to the upper surface of the prostate and was confused if this was a prostatic lesion or a bladder pathology. Much research on the net confirmed that this was indeed cystitis cystica. See: Ultrasound images and case study of cystitis cystica
Some studies suggest that cystitis cystica or cystitis of the bladder with cyst formation, may not be as rare as one thinks. But I disagree, this being the first case I have come across after many years of urinary bladder and TRUS/ transrectal ultrasound imaging.