Doppler imaging of the carotids is not as difficult as you think:

The main purpose of studying the carotid arteries (the common carotid artery (CCA), the internal carotid (ICA) and the external carotid (ECA) and lastly the Vertebral artery - is to assess the possibility of stroke due to stenosis and embolism. Any of these conditions in the carotid system, can be fatal at worst or at best result in serious disability including hemiplegia, or partial paralysis.
The following are the main steps to evaluating the carotid arterial system:-

1) differentiate the CCA from the IJV (internal jugular vein)- this is easy as the Jugular veins shows a typical venous flow on Color Doppler imaging and has thin walls which are not visualized clearly on B-mode ultrasound imaging.

2) differentiate the ICA from the ECA. Here the going becomes a little difficult, as the bifurcation of the CCA into the ICA and ECA is not always clearly visualized (see image above).
For more details of step -2 (see: http://www.ultrasound-images.com/vascular.htm )
The temporal tap sign : see Spectral Doppler waveforms of ECA below) is vital to clearly distinguish the ECA from the ICA.




























3) Thirdly the next step in carotid sonography is visualization of the carotid arterial walls and the measurement of the combined thickness of the inner layer-the intima and the middle layer- the media. This is called IMT or intima media thickness.

Baker cyst and other musculoskeletal ultrasound cases:

These 3 ultrasound images show a typical large Baker cyst in the popliteal fossa. The cyst measuring more than 5 x 2.5 cms. is the result of an extrusion of the synovial membrane from the knee joint via an opening in the postero-medial aspect of the joint. The result is a synovial membrane lined cyst in the popliteal fossa, just behind the knee joint.
Over a period of time the fluid within the Baker cyst is thick, almost gelatinous, making aspiration difficult. See: http://www.ultrasound-images.com/musculoskeletal.htm
Visit this page : Musculoskeletal ultrasound for a pictorial review of MSK sonography, cases/ and images. The various topics on this page include:
Cruciate liagment tear,
Epidermoid cyst
Transient synovitis
Olecranon bursitis
and inguinal hernia.
Also, I have added images / cases of hemangioma of the abdominal wall,
abductor hallucis hypertrophy
and fractures of the rib and the forearm bones, as well a rare case of intracranial dermoid.
View on...

Carcinoma of gall bladder:

This was a patient of right hypochondrial pain. Sonography of the liver and gall bladder show (see ultrasound image above), a poorly defined mass in the region of the Gall bladder fossa with a large calculus trapped within the mass. (Image is courtesy of Vikas Shukla, MD, India). This is a typical appearance of late stage (advanced) gall bladder carcinoma with the cancer having spread beyond the confines of the GB wall. For more images and details of this disease, visit:
http://www.ultrasound-images.com/gall-bladder.htm
You can find a lot many images of this other pathologies of the GB at this site. Among the topics I have covered on this page are:
1) Normal variants of the gall bladder 2) Normal sonographic anatomy of GB
3) GB carcinoma 4) Mirizzi syndrome 5) 3-D imaging of GB calculi
Also visit: http://www.ultrasound-images.com/gb-wall.htm
where there are images and description of GB polyps and diffuse as well as segmental adenomyomatosis of gall bladder.
On the page: http://www.ultrasound-images.com/gb-mucocele.htm
you will find coverage of mucocele and pyocele of the gall bladder.
What is the sonographic appearance after cholecystectomy/ surgical removal of the GB?
Visit: http://www.ultrasound-images.com/cholecystectomy.htm

Free floating particles in amniotic fluid- an ultrasound video

This ultrasound video clip shows multiple particles/ particulate debris floating within the amniotic fluid in a kind of Brownian motion. This was a 3rd trimester pregnancy and free floating particles are a common finding in this phase of gestation. They are said to be result of shedding of vernix caseosa from the surface of the fetal skin. Recent research suggests that presence of free particles in the liqor amnii is a good sign of fetal lung maturity.
More ominous causes of particulate matter in the amniotic fluid include hemorrhage into the liqor.
Reference: 1) http://www.ajronline.org/cgi/reprint/176/3/607.pdf (free article)
2) http://www.jultrasoundmed.org/cgi/content/abstract/2/3/107
3) http://www.ncbi.nlm.nih.gov/pubmed/7506913

For more articles and ultrasound images of liqor / amniotic fluid pathology visit:
http://www.ultrasound-images.com/amniotic-fluid.htm

Have a look at another sonographic video showing these particles dancing in the amniotic fluid:

A nice e-book and sonographic atlas on scrotal calculi

I have published a nice e-book on scrotal calculi.
It is actually an ultrasound atlas of high resolution images of calcifications/ scrotal pearls.
Check this link: https://www.regnow.com/softsell/nph-softsell.cgi?item=16637-4
This e-book is in MS Power Point format...

In case you wish to get the e-book in PDF format gp to this link:
https://www.regnow.com/softsell/nph-softsell.cgi?item=16637-6
All you need to open this e-book on scrotal calculi in PDF format is adobe reader (a free download from www.adobe.com

Sonography of penile AVM:

This ultrasound/ Color Doppler image shows multiple vessels in the glans penis and adjacent part of the penis in a middle aged male patient. This patient presented with post coital bleeding from the penis. Such a case and Color Doppler study presenting such appearances are either hardly available or known in medical literature. I have presented more Ultrasound and Color Doppler images of this very rare case at: http://www.ultrasound-images.com/penis.htm
The images show the presence of both arterial and venous flow pattern in the mesh of of vessels
in the glans penis. This is a typical appearance of arterio-venous malformation of the penis.