64 Slice MSCT - Friend or Foe?

This blog had an earlier post which covered the 64slice MSCT among other things. Interestingly enough, this was also covered by JAMA in its Feb 15th issue.

It is well known that we probably have the highest number of 64 Slice MSCT (64 MSCT) scans per 100,000 population in the world. For some reason, there are almost 6 such machines in the Klang valley. Undoubtedly, the 64MSCT does have good clinical use, as it does give better definition, thinner slices and requires less scan time. This in turn means less breath holding for the patient and less motion artifacts for the doctor. The 64MSCT also allows for 3D volumetric reconstruction. The software is much more sophisticated.

Balanced against these good points, there is the tremendous amount of radiation the 64MSCT exposes the patient to. Almost the equivalent of 500 plain CXRs per cardiac angiogram scan, and 2000 plain CXRs if you do a total body scan from head to toe. I wish this was told to the patient, in terms of full dislosure. In fact there is some concern that females and males with chest scans run the risk of Breast Cancer.

This is not the biggest problem. The MSCT has also brought about a new medical problem of "turf division". For a long time, Xrays and imaging techniques generally have been under the responsibility of the radiologist, who are experts in Xray shadows and their interpretation. They better understand the physics of Xrays. When you see an image, they are better trained to differentiate real from artifacts. Even the expert radiologist sometimes is uncertain and make mistakes, what about a cardiologist who visits a scan center for 2 weeks and become an "expert", reporting 64MSCT?

This logically leads to the next question of how good the scans are, in particular the non-invasive coronary angiogram. Well, in the best of centers, where dedicated radiologist/MSCT trained cardiologist working on these scans day in day out, the positive predictive value of about 93-95% (these numbers vary depending on the part of the coronary tree we are examining) and a negative predictive value of 97-98%.

What are our own findings, given that many of our scans are interpreted by consultants who report the 64MSCT part time. There is no data coming out, apart from the correlation work being done in Sarawak GH, of which results we are eagerly awaiting. The other big issue is that a medical diagnostc technique with known dangers are being allowed to be marketed to the unknowing public, without full disclosure of the risk. This the authorities must take note.
So the 64MSCT, friend or foe, you decide?