Normal renal arterial color doppler study

Right renal artery is visualized on color Doppler imaging: often part of the renal artery is visualized in one image. By angling the probe in various positions, it is possible to see part or whole of the renal artery. I find it more difficult to visualize the left renal artery than the right. But this can vary from patient to patient depending on viewing conditions, bowel gas and the acoustic window.

                                                                           
The right renal artery in spectral doppler tracing (above) shows normal waveform and the PSV (peak systolic velocity) is almost 60 cms./sec. at a doppler insonation angle of 42. The RI is= 0.6. The normal PSV of the renal artery is appx. 80 to 120 cms./second. It is considered abnormal if the PSV> 180 cms./second and renal artery stenosis is likely.


The segmental artery of the right kidney is studied in this spectral Doppler tracing (below). It shows an RI of 0.6 which is normal. Any RI of > 0.8 is highly suggestive of renal arterial stenosis.

The left renal artery also shows similar findings.

The spectral Doppler waveform of the left renal artery and left renal segmental arteries is also normal.

A sonographic atlas of the thyroid- on Amazon

This short handbook and ultrasound atlas of the thyroid should serve as a guide for the busy sonologist, radiologist or medical practitioner who wishes to gain insight into the intricacies of sonography and color Doppler imaging of the thyroid. A short section on the appendix towards the end of the book casts light on ultrasound imaging of common pathologies of the appendix. This book is sold on amazon at a reasonable price. 

Cerebral edema in neonates

Cerebral edema remains one of the commonest problems encountered whilst doing sonographic imaging of the neonatal brain. It has been graded into mild, moderate and severe depending on the degree of effacement or compression of the ventricular system- the lateral and 3rd veintricles mainly, and also loss of the sulcal pattern of the baby's brain.
These ultrasound images of severe cerebral edema show the typical appearance with the lateral and 3rd ventricles virtually compressed out of visibility by the edematous neonatal cerebral tissue (the sulcal pattern is however, still preserved and is visible):
Sagittal section:

Coronal section:

Color Doppler coronal section image:

Coronal section brain (all images of same neonate):

Visit: http://www.ultrasound-images.com/pediatric.htm#Cerebral_edema_in_neonate
for more on this topic.

Twinkle (color Doppler) artifacts in urinary calculi

It has been observed that small color flow artifacts called twinkle artifacts form around and posterior to kidney, ureteric and bladder stones. These color twinkle artifacts can at times be helpful in recognizing small urinary calculi that may be sometimes be obscure. The color Doppler ultrasound video clip below shows a typical case of twinkle artifacts behind a left vesico-ureteric calculus, measuring 5 mm.
 

 
These color Doppler and B mode ultrasound images reveal the twinkle around the left VUJ stone in detail.

Mild hydronephrosis is present in the left kidney due to back pressure changes in left ureter.
My personal observation is that twinkle artifacts can at best help confirm the presence of small renal/ urinary calculi and not be used in isolation to sonographically diagnose a urinary calculus. These artifacts are better seen on lowering the pulse repetition frequency (PRF) to optimal levels. Twinkling can at times be used to aid diagnosis of urinary stones when acoustic shadowing may be doubtful.
References:
http://radiology.rsna.org/content/259/3/911.abstract (abstract - effectiveness of color Twinkle artifact in detecting small urinary stones).
Images and description of twinkle artifacts
Also visit : http://www.ultrasound-images.com/ureteric-calculi.htm
and:  http://www.ultrasound-images.com/renal-calculi.htm

Ultrasound study of gastric band

I have described a little about gastric banding at : http://www.ultrasound-images.com/git.htm#Gastric_band_%28gastric_banding_in_obesity%29
Gastric band is a simple "tourniquet" around the upper part of the stomach, just below the fundus, aimed at reducing the functional volume of the stomach. This is useful in controlling the food intake in obese patients. What has ultrasound got to do with gastric band? Plenty- ultrasound imaging of the gastric band post-surgical case helps determine the position and effectiveness of the gastric band. How good is ultrasound at imaging it? Have a  look at the link above.

Sonographic atlas of thyroid and appendix

I have published a short handbook of "Sonography of the Thyroid and Appendix"... This book is available at this link online:
Sonographic atlas of the thyroid and appendix
This short textbook is published by Jaypee brothers in India and is marketed worldwide online by a number of publishers.
See: http://www.printsasia.com/book/Step-by-Step-Sonographic-Atlas-of-Thyroid-Appendix-Joe-Anthony-8184489986-9788184489989
Shown here is a snap shot of the cover:

 

This book attempts to bridge the gap in imaging of the thyroid using high resolution ultrasound images of the thyroid. Almost very thyroid pathology is covered in this short ultrasound atlas of the thyroid and appendix. 

This handbook of ultrasound imaging of the thyroid also has a short section on ultrasound imaging of the appendix. Here we cover most of the pathologies of the appendix as visualized on ultrasonography.
    Priced at very affordable rates, both in India and abroad, this short atlas of ultrasound of the thyroid and appendix should cater to the newbie (beginner) in the field of sonography of the thyroid as well as the appendix, both of which are relatively gray areas in ultrasound imaging.
Other dealers selling this text book of thyroid sonography are:
1) Sonography of the thyroid-  Jaypee brothers website
2) http://www.alibris.com/search/books/qwork/16697477/used/Sonographic%20Atlas%20of%20Thyroid%20%26%20Appendix
3) http://www.amazon-sy.com/?q=en/Product/view/12856/198
Another online dealer who sells this handy manual of thyroid imaging is:
4) http://www.bookshopofindia.com/search.asp?action1=default&bookid=9081727
5) http://www.maansu.com/9788184489989
6) Sonographic atlas of the thyroid and appendix- Amega books
7) http://www.flipkart.com/b/books/step-sonographic-atlas-thyroid-appendix-book-8184489986
8) http://www.amazon.co.uk/Step-Sonographic-Atlas-Thyroid-Appendix/dp/8184489986 (sold on amazon.com in UK)
9) http://www.waterstones.com/waterstonesweb/products/joe+antony/sonographic+atlas+of+thyroid+26+appendix/8293107/   (also on waterstones.com in UK)
10) http://www.whsmith.co.uk/CatalogAndSearch/ProductDetails.aspx?productID=9788184489989
(whsmith.com in UK)
  11) http://www.fishpond.com.au/Books/Sonographic-Atlas-of-Thyroid-Appendix-Antony/9788184489989
in Australia
12) http://www.bookdepository.co.uk/Sonographic-Atlas-Thyroid-Appendix-Antony/9788184489989
(in UK)
13) http://www.sparkbooks.in/cart/index.php?main_page=product_info&cPath=1_49&products_id=11270
14) http://www.medilinebooks.com/onlinebooks.php?category=Step%20by%20Step%20Series&PHPSESSID=0f84112845b9839f5351c838b487834b (mediline books)