Splash created by 64-slice CT obscures other radiology advances

No development since I began covering medical imaging in late 1997 has generated the level of excitement and potential for change as the 64-slice CT scanner. Plenty has happened in those years: the flourishing of CAD and virtual colonoscopy, 3T MR and parallel processing, continued advancements in ultrasound, PET/CT and SPECT/CT fusion imaging, and the ascendancy of PACS and imaging informatics.

But nothing has taken off with the roar and flash that have characterized the 64-slice CT scanner. We started taking a close look at this in November 2004 with a review of the planned RSNA offerings from all the major vendors. Since then, a number of early adopters have picked up the 64-slice banner and run with it. In last month's cover story, we examined the revolutionary potential that CT angiography-which is particularly well performed with 64-slice scanners-has on the practice of radiology. This month, we look at some of the practical issues that are cropping up as facilities adopt these new scanners.

To no one's great surprise, cardiac imaging is a driving force for adoption. The new scanner's ability to very nearly stop the heart and, barring that, to capture enough images that you can page through to get the best view of any element of cardiac anatomy astounds those who have used slower scanners in the past. Naturally, vendors are taking every advantage of this capability, pushing the new scanners into the cardiology marketplace. Training questions, addressed in our March issue and again in this one, are coming to the fore. And, as always, turf questions lurk in the background.

But look beyond cardiac, and you'll find other applications as well. As noted in our cover article, trauma is a big one. Three-D reconstructions of 64-slice scans (note our cover image) can provide incredible detail throughout the torso. Of course, when the scanners are located in the ER suite, they naturally prove useful for emergency heart scans.

All of this comes at a cost. Prices for the new scanners are coming down, as are those for the older 16- and eight- and four-slice versions they replace, but at $1.4 million, they're still pricey. Worse, some facilities may be buying the new scanners and using them just like the old scanners they superseded. These are powerful new tools, and they need to be put to their highest use.

This problem will resolve with time. Expect the next RSNA meeting to showcase a raft of studies highlighting new uses for 64-slice scanners and the new information being revealed when they are used in more traditional types of scans.

Another big issue is slice overload, a problem that emerged with 16-slice scanners and got four times worse when the 64-slice scanners arrived. We've heard of some cardiac scans that go as high as 7000 individual images. It's amazing that we found facilities that are managing their 64-slice data by loading it onto CDs and DVDs. This, of course, is not optimal. The best use of this technology will require a PACS with sophisticated data management algorithms and powerful workstations that can readily manipulate the data. Lots of storage won't hurt either: a 7000-image scan can require 3.5 terabytes of storage space.

Finally, radiologists need to be cautious in how they approach and promote 64-slice scanners. With faster patient throughput and the high capital cost of the new scanners, there will be pressures to overuse the technology. As this happens, dose and healthcare cost concerns may be raised and will need to be addressed.

Those issues notwithstanding, the 64-slice scanners are destined to become an important new element in imaging's technological tool set and to produce significant gains in the quality of medical care.