FYI: Contrast dye for echos!

[Lani]

to detect unperfused (without blood supply) areas of the heart

J Ultrasound Med. 2007 Jun;26(6):739-48. Links
Parametric detection and measurement of perfusion defects in attenuated contrast echocardiographic images.

Yoshifuku S, Chen S, McMahon E, Korinek J, Yoshikawa A, Ochiai I, Sengupta PP, Belohlavek M.
Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota, USA.
OBJECTIVE: Attenuation of radio frequency (RF) signals limits the use of contrast echocardiography. The harmonic-to-fundamental ratio (HFR) of the RF signals compensates for attenuation. We tested whether HFR analysis measures the left ventricular nonperfused area under simulated experimental attenuation. METHODS: Radio frequency image data from short axis systolic projections were obtained from 11 open-chest dogs with left anterior descending or left circumflex coronary artery occlusion followed by left atrial bolus injection of a perflutren microbubble contrast agent. Clinical attenuation was simulated by calibrated silicone pads interposed between the epicardial surface and the transducer to induce mild (7-dB) and severe (14-dB) reduction of the backscattered RF signals. Harmonic-to-fundamental ratio values were calculated for each image pixel for 0-, 7-, and 14-dB attenuation conditions and reproducibly showed a "perfused area" and a "nonperfused area." A reference nonperfused area was obtained by manual delineation in high-quality contrast scans. RESULTS: Correlations of the HFR-detected and manually outlined perfusion defect areas were R = 0.92 for 0 dB, R = 0.94 for 7 dB, and R = 0.90 for 14 dB; the mean difference was less than 0.36 cm(2) (negligible) in all 3 attenuation settings. Conclusions. Attenuation compensation by our HFR method allows precise measurement of myocardial perfusion defect areas in contrast scans with simulated high level of attenuation.
PMID: 17526605 [PubMed - indexed for MEDLINE]

[Lani]

the previous was a review of the first 20 of 90 abstracts on contrast echocardiography on PUBMED (national library of medicine)...showing there are many reasons to get contrast echos (most not for items related to herceptin),,,but the following explains that there are people who are hard to image due to obesity, perhaps lung disease (reference somewhat unclear to me--whether it is the lung disease which makes imaging difficult or whether it compounds the difficulty of interpreting the results of imaging which is not difficult or whether it makes other cardiac problems more likely for which contrast imaging helps provide the answer...). It is from the president of the society and explains many facets of a decision to use or not use contrast.

Obviously I went to all this trouble as I was HORRIFIED that you would even think and use the word NEGLIGENT based on my report of what I had understood from an echo tech (perhaps I didn't understand her well, perhaps she didn't communicate well, perhaps she wasn't omniscient--all-knowing)

I knew when I posted that I did not have sufficient time to do a literature search so I stressed my lack of qualification to give an opinion and asked that perhaps RobinP could help out.

I provide information to give hope, food for thought and ammunition and hope it will be mulled over, further information sought, and my premises questioned appropriately. Please do not jump to conclusions based on them as I am not qualified to give advice and work assiduously NOT TO. God forbid you accuse your doctors who have spent their careers gaining expertise in their specialties and subspecialties based on the little information I provided, the rather anecdotal nature of it (something I work extremely hard to avoid), and my lack of an even rudimentary background
in this very complicated and exacting field.

Rather than causing you to assume negligence, I would have hoped it might have caused you to ask politely why the contrast agent was utilized so that they might explain in detail their reasoning. It is your right to ask questions and their duty to explain until you understand enough to consent.

I too post items which might worry some of you--when I do I try to be as specific as possible of what seems to be known, what does not seem to be known and whether it is her2 specific. It seems I need to second and third guess myself even more when I do more than just post abstracts or news
items.

President’s Message
Journal of the American Society of Echocardiography - Volume 20, Issue 5 (May 2007) - Copyright © 2007 American Society of Echocardiography - About This Journal

American Society of Echocardiography News
President’s Message

Should You Be Using Contrast?



PII S0894-7317(07)00245-3



Michael Picard, MD, President, American Society of Echocardiography

In even the best echocardiography laboratories with even the best echo machines and even the most experienced sonographers, it is challenging to obtain adequate images. When this occurs, our ability to provide accurate and reproducible assessments of left ventricular (LV) global and regional function may be compromised. As the weight of our population increases and lung disease continues to confound our clinical assessments, echocardiographic evaluation and quantitation of LV function can be more challenging yet even more important. For both our overweight and our lung diseased populations, the differential diagnosis includes a variety of heart diseases and echocardiography is a mainstay in these evaluations.
One way to measure whether your laboratory provides quality echocardiography is to ask in what percentage of cases is the LV endocardium seen well enough to accurately measure the LV ejection fraction (EF) and in what percentage of cases is the endocardium seen well enough that all segments of the LV myocardium can be assessed for regional wall motion abnormalities such as in a stress echocardiogram. While these actual percentages vary from lab to lab and are a function of the types of patients referred, we should be striving to increase those percentages well above 80% and with time even higher.

So, how can we meet that goal and improve upon our ability to accurately assess and measure LV function, even when we have populations that are challenging to image? One answer is to apply contrast for LV opacification.

Intravenous (IV) echocardiographic contrast agents have now been available for many years. A body of literature has accumulated demonstrating their value. Yet utilization lags behind expectations. Explanations for this have included the requirement for additional time and effort for IV insertion and the need for additional personnel for the injection of the agents. For selected patients, the benefits of the contrast enhanced image can out weigh these concerns.

Where and why should you consider contrast?

1 EF – An LVEF should be calculated on all complete transthoracic echocardiograms. While there are many ways to do this, including the ASE recommended biplane method of discs, adequate visualization of endocardial borders is required. When there is inadequate visualization, LV contrast can be used to identify the borders thus improving the accuracy and reducing the variability of the LVEF measurement. It may even be faster to make the tracings.

2 Stress echo – As for the LVEF, an accurate interpretation of a stress echo is only possible when a sufficient amount of the LV walls can be seen for each of the coronary territories. Contrast enhancement again can improve image acquisition and confidence in the interpretation especially for those with less experience. Many of these patients are already getting IV placement and additional personnel are present who can assist with injections.

3 Extending echo – Bedside echocardiography is an important tool in the care of many critically ill patients. When image quality suffers, contrast may improve the diagnostic yield, shorten the time to diagnosis, and reduce the need for other tests.

4 Prepare for the future - In select institutions, myocardial perfusion with IV echocardiographic contrast injection is underway with enthusiasm. There are many potential uses for echo assessment of perfusion including rapid evaluation of the patient with chest pain, the assessment of reflow or no-reflow after intervention, and the assessment of viable myocardium in order to predict recovery of function in patients with coronary artery disease. In addition, we have gained many insights into the intricacies of coronary physiology from experiments that have used contrast. It remains to be seen for which indications perfusion assessment with echo contrast will be of value for everyday use. By using contrast now for LV opacification, your lab personnel will become familiar enough to be able to make the jump to echo perfusion when the time is appropriate.

5 Improving efficiencies – While it may appear that contrast adds another step to the echocardiogram, protocols that fit the needs of individual labs can be established. Such protocols should outline a work flow that is efficient for your operation.
All labs can benefit from the appropriate use of contrast to improve LV endocardial border definition in selected patients. The information that you obtain will 1) improve confidence in the results of the report, 2) increase your ability to accurately and reproducibly measure LVEF, 3) improve your regional wall motion assessments, particularly in stress echo, 4) improve laboratory efficiency, 5) reduce the need for additional testing and 6) keep up with competing technologies. All of these advance quality imaging and your lab’s image.

PS--one reason why contrast may not be used more at Stanford(here I am just speculating as perhaps I misunderstood the tech) is the fact that all their echo machines have now all been upgraded to 3D echos(or so I was told), a technology so new (and providing so much more detail and information) that they don't yet have a way to charge insurance companies for it!

Signing off now!

Thanks Lani. I plan to ask my cardiologist if she ordered the echo with contrast (or if the tech took it upon herself to suggest it). Result of the test, which included a stress portion, was generally good, and my LVEF was 60%. A previous echo indicated a small pericardial effusion and also an enlarged fat pad (one can be confused with the other), so she may have been trying to determine if it was one or the other, although none of your posts refer to either. Whatever the case, I don't like to think that an unnecessary (and dangerous) test was ordered without good reason. When I have an answer, I'll post further.

Lani, we were probably posting at the same time, so I didn't read your last post until now. Please don't fret--I wasn't planning to accuse my cardiologist of negligence. I like her way too much to risk losing her. But I was certainly planning to ask why the contrast was suggested, since it does pose certain dangers. And my decision to question her on the use of a contrast was not based on your post but on the recent news alerts about echo contrasts and the probability that such contrasts will soon be given "black box" labeling. I was also surprised that the tech wanted to use a contrast, as I had requested an echo to avoid another MUGA injection!

I'm sure that we all welcome your posts--at least I do. I get Google alerts on everything happening on HER2 but I often don't have time to go through them all, and I always know that when I don't, you'll have done it for us. So thanks.