what is diaphragmatic attenuation?

I just recently had a stress nuclear study  and was told that I did very well in all phases.I just recieved a copy of the Doctors office notes that talks about "abnormal stress imaging study"with reference to "diaphragmatic attenuation".I am asking for information that would explain  the condition mentioned and how it relates the most favorable results I recieved.There was no mention of any other problems and was told I did not have to return for testing for 2 year.

I am 73years old,in very good health,excersing both with weight training(3xweekly) and cardio(7xweekly),171 lbs.,5'10" ,b/p 121/70 with med.and body fat at appx.20%

Thank you


This discussion is related to Radiologic Exam Report.

[kenkeith]

Avoidance of falsely positive results depends on distinguishing reality from artifact, in turn depending on images of highest quality. In radionuclide cardiac imaging, an inferior wall artifactual defect, so called diaphragmatic attenuation, is particularly common and vexing

The most common artifact on thallium scans in our laboratory has been posterior myocardial attenuation, mostly in males. In the past this has been thought due to the position of the diaphragm. Diaphragm is of no significance and a misnomer, but further evaluation for posterior myocardium attenuation (medically significant) to determine if there is a posterior defect and rule out an artifact. "It is suggested that a male with a flat, wide chest is more prone to posterior myocardial attenuation. If a posterior defect is present in this type of patient it is suggested he be further evaluated to rule out artifact".

For some insight mild reduced tracer "uptake" in the inferior wall is commonly seen in men with large chests. The inferior wall is furthest away from the detector, photons from the inferior wall thus travel longer distances and are attenuated (thinning, weakening, diluting), giving the appearance of reduced uptake.
"The phenomenon is often called diaphragmatic attenuation, which is a misnomer. The diaphragm is very thin and does not couse the attenuation, the diaphragmatic portion of the LV ( the inferior wall) is the affected, though".