Vendors offer advice on optimal cardiac imaging

Toshiba

Toshiba has a 32-slice and a 64-slice scanner routinely imaging hearts, said Robb Young, CT product manager for cardiology.

"The 32-slice is at Johns Hopkins, and the 64-slice is at Fujita Health University in Japan, and that's where we've been developing contrast protocols," he said.

The Aquilion 32/64 has a bolus-tracking system for cardiac imaging called Sure Start, part of Toshiba's Sure Technologies suite of applications. Higher slice scanners have two advantages: coverage and shortening of the breath-hold, according to Young.

Protocols:

16 slice: 120 to 140 cc contrast, 40 to 60 cc saline , flow rate 3.5 to 4.5 mL/sec, scan time 20 to 30 sec

32 slice: 80 to 100 cc contrast, 40 to 60 cc saline, flow rate 3.5 to 4.5 mL/sec, scan time 10 to 15 sec

64 slice: 60 to 80 cc contrast, 40 to 60 cc saline, flow rate 4 to 5 mL/sec, scan time 5 to 10 sec

Philips

Philips will release the 40-slice Brilliance CT scanner at the end of next month, said Phillip Prather, director of global cardiology CT.

"It has been in beta testing in more than seven centers worldwide, and we have the experience of more than 3000 patients, more than 500 of whom have been on cardiac studies," he said.

Philips has worked with an injector manufacturer to tie in its Bolus Pro Ultra bolus-tracking system in with the automatic injector systems.

"You can push a button and the two systems will work together to initiate and acquire the scan," Prather said.

Protocols:

16 slice: 40 cc contrast at 4 cc/sec followed by second injection of 40 to 60 cc at 2.5 cc/sec, then 30 to 50 cc of saline at a 2.5 cc/sec injection rate, scan time 17 to 20 sec

40 slice: 80 cc contrast at 5 cc/sec, 40 cc saline at 5 cc/sec, scan time 8 to 10 sec

Siemens

Siemens has a handful of 64-slice scanners in clinical use worldwide. Its new Somatom Sensation 64 includes a bolus-tracking program called CARE Bolus, which allows the user to trigger the scan as soon as the bolus arrives in the region of interest. CARE Bolus is offered as part of the standard package for all high-end multislice CT applications, including cardiovascular work and any general CT angiography, said Haw Loke Gie, clinical marketing manager for Siemens' CT products.

"No matter how accurate you are with your contrast timing, no matter how beautiful your injector is, how dense your contrast is, it all comes down to the scanner," said Murat Gungor, marketing manager of the Somatom Sensation products.

Protocols:

16 slice : 80 cc contrast, 40 cc saline, flow 4 cc/sec, scan time 20 sec

64 slice: 60 cc contrast, 50 cc saline, flow 4 to 5 cc/sec, scan time 9 sec

GE

GE will soon enter the 64-slice market with the LightSpeed Volume CT. Its bolus-tracking system is called SmartPrep.

"This system provides unprecedented image quality almost instantaneously, which should provide significant impact in cardiovascular medicine and trauma," said Dr. Dennis Foley, a professor of radiology at the Medical College of Wisconsin.

Protocols:

16 slice: 90 cc contrast, 5 cc/sec flow rate, followed by 30 cc contrast combined with 30 cc saline at 3.5 cc/sec, followed by 40 cc saline at 3.5 cc/sec

64 slice: 60 cc contrast, 5 cc/sec flow rate, 30 to 50-cc saline push, scan time 5 sec