iRADiX

Doppler traces and Technical Thresholds

In previous entries we examined some issues arising from X-ray (Please Repeat), CT scan (high resolution), and Ultrasound (Snowstorms). Let us examine some other quality issues using the tool of “Technical Review Meeting” in the web world. Hopefully these will be applied practically. Feedback from readers regarding their experiences, pitfalls and lessons learnt will help improve the common pool of knowledge.

A fresh understanding of particulars

If a source is emitting sound waves, the frequency of reflected sound from an object in its path increases or decreases if the object is moving towards or away from the source respectively. This is the Doppler Effect (Christian Andreas Doppler-1803-1863), an Austrian mathematician) and the change in frequency is the Doppler Shift. (1)

In one of the forum discussions of IRADIX a question was asked, whether you use the Doppler mode while doing a routine ultrasound. In previous blog we had seen some Snowstorm-PRF issues. As told earlier, many vendors have targeted clinical departments as their market to sell them imaging equipments. This has led to increase in Quackery and some erosion of ‘Radiologists’ ground.

The positive outcome of this could be that we have to raise our bar so that they will still require us. It also made me reflect on the nature of sensation (Vico), reflection, education (Rousseau’s Emile) and remember the words of Francis Bacon

“The true business of philosophy must be...to apply the understanding...to a fresh understanding of particulars” (Novum Organum-1620)

Examining some liver particulars one Old Fox remarked

“I tell these self-styled experts to just show me the trace of the branches of the hepatic artery. That settles the issue for most of them”.

Most private imaging departments keep an experienced MRI person to standardize the reporting and scanning protocols. What they do to them after they think that their work is over is another issue.

A Business model

Get an established experienced radiologist to start your set-up, establish all the reporting and scanning protocols, train the technicians, take some good lectures demonstrations of your centre and after your centre has been established in the market, you can keep two juniors for almost the same salary which you pay this fellow. Once the consultants are there in your commission-circuit, you need not worry about things. This “business-model’ is being applied by even some senior doctors who tend to get increasingly rude with the radiologists who toil to establish the reputation of the new centres, once they feel that their work is done.

(For a more detailed nuanced narrative –

See Blog: The Bazaar: Reporting versus Consultation: Trends of Commoditization)

This journey of setting the protocols, examining the expectations of clinicians, made me examine other modalities when I became a radiology incharge in a larger set-up (after having bid farewell to a close ‘friend’ with whom I started a MRI centre from scratch-over 7 years ago. ).

Once one is responsible for all modalities, one has to .(.as Francis Bacon said)… to apply the understanding..to a fresh understanding of particulars.

When coming to examining the particulars, one has to go back to collected memories of learning. In school we were taught about Least Common Multiple.

What should be the threshold for scanning?

In a setting where every clinician feels (erroneously) that they do better Ultrasound than radiologists, one can pick up the liver-normal and abnormal, and see how they approach focal and diffuse liver diseases, in different age groups.

The least common multiple can be their approach to a liver transplant case.

Ultrasonography(US) is the initial modality of choice for detection and follow-up of early and delayed complications from all types of liver transplantation. Vascular complications are the earliest to occur and may manifest as thrombosis or stenosis of the hepatic artery, portal vein, hepatic vein thrombosis as well as hepatic artery pseudoaneurysm. Biliary complications include leak or stricture. Neoplastic disease in the transplanted liver may represent recurrent neoplasia or post transplantation lymphoproliferative disorder. Parenchymal disease may take the form of a focal mass or diffuse parenchymal abnormality. Perihepatic fluid collections and ascites are common after liver transplantation. Knowledge of the surgical technique of liver transplantation and awareness of the normal US appearance of the transplant liver graft permit early detection of complications and prevents misdiagnosis (2).

If one can set the parameters of the ultrasound-doppler unit to tackle cases of Liver transplants, it can be a good bar to make the self-styled experts to match up against. The exercise also will cover the points discussed regarding approach to Imaging and reporting-

Try writing the medical biography of the patient through the radiological perspective rather than just a report.

See blog : Is there any change in Management.

Video traces of Portal vein and hepatic artery

{rokbox title=|Portal Vein Doppler| thumb=|http://i3.ytimg.com/vi/R4W7-Rcn0SQ/default.jpg| size=|425 373| album=|demo|}http://www.youtube.com/watch?v=R4W7-Rcn0SQ{/rokbox}

{rokbox title=|Hepatic Artery Doppler| thumb=|http://i1.ytimg.com/vi/H9EQsaKk5jU/default.jpg| size=|425 373| album=|demo|}http://www.youtube.com/watch?v=H9EQsaKk5jU{/rokbox}

Images and Videos: Courtesy: Dr. Anuj Mishra, MD, FRCR, Consultant and Head,

Department of Radiology, Organ Transplant Centre, Central Hospital Tripoli.

Acceleration time-Represents the time from end diastole to the first systolic peak

Resistive index=PSV-PDV/PSV

PSV: Peak Systolic Velocity, PDV: Peak Diastolic velocity.(Source: Ref 2)

Of causes and nature

Standardizing and setting the bar to one such topic (the post transplant hepatic artery in this case) can help standardize many things in the department and also keep the ‘self-styled experts’ at bay.

Remembering Francis Bacon again-His enduring place in the history of philosophy lies in his single minded advocacy of experience as the only source of valid knowledge and in his profound enthusiasm for the perfection of natural science.

We as radiologists , can view ourselves as natural scientists.

Bacon’s hope for a new birth of science depended not only on vastly more numerous and varied experiments but also the use of a new method-tables of presence, of absence and of degree-to establish the true causes of phenomena (the subject of Physics-as the Doppler Effect remembering Christian Andreas Doppler) and the true ‘forms’ of things (the subject of metaphysics-the study of the nature of being) studied and illustrated as to why some experts were interested in “ironing-with-the-probe”.

Notes and suggested further reading:

1. Kenneth Myers and Amy Clough: Making Sense of Vascular Ultrasound-Page 6
2. Crossin JD, Muradali D, Wilson SR: US of Liver Transplants: Normal and Abnormal Radiographics 2003;23:1093-1114.