Increased speed in single-source CT

Maintaining high spatial resolution at high gantry rotation speeds has long proven challenging in CT. With patients who are unable to remain still for long periods, or with scans involving fast-moving organs such as the heart, the shortest possible scanning time may reduce image motion artifacts. The new gantry design of the SOMATOM Definition Edge CT system has a very high temporal resolution of 142 ms. The system allows a pitch of 1.7, thus enabling an acquisition speed of up to 23 cm/sec, and is capable of reconstructing 384 slices per rotation. With the SOMATOM Definition Edge, a typical thorax-abdomen examination can be performed in about two seconds, potentially minimizing the need for patient breath-holding during scanning. A 6-foot patient can potentially be scanned in 8.3 seconds at full speed using the system.


Dual Energy for single-source CT

Until now, Dual Energy examinations with single-source devices were complicated processes that resulted in dose levels several times higher than levels seen with a customary single-source scan. In keeping with Siemens' ongoing dose-reduction efforts, The SOMATOM Definition Edge CT system introduces a new scanning technique into single-source CT examinations. During the Dual Energy examination, the SOMATOM Definition Edge performs two CT scans in succession with different energy levels, with each scan potentially using only about half the dose applied in normal mode. Together, the two scans deliver the image signal required. Also, since the voltage in each scan is fixed, the physician can use additional dose-reducing techniques, including CARE Dose4D - a fully automatic radiation exposure control system that adjusts the dose in real time according to the area of the body being scanned. Additionally, the SOMATOM Definition Edge CT system uses the rapid iterative reconstruction method SAFIRE (Sinogram Affirmed Iterative Reconstruction), which may also help to reduce dose levels.* These Siemens offerings enable the generation of Dual Energy images via a single-source system without excessive patient radiation dose.

Advantages in cardiovascular imaging

The new SOMATOM Definition Edge may also offer clinicians a major advantage with its marriage of high temporal resolution and the high degree of spatial resolution provided by the Stellar Detector. Since coronary arteries constantly move along with the heart, the clinician must obtain CT images at a high temporal resolution to sharpen coronary artery images. The sharpness of image provided may improve the clinician's ability to detect coronary stenosis and atherosclerotic changes in plaque formations. And the high spatial resolution may potentially improve the physician's ability to safely detect, for example, in-stent restenosis of stents smaller than 3 mm in diameter.

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