256-slice scanner captures heart, brain in single rotations

The wide area detector onboard Toshiba's 256-slice CT records subtle changes in blood flow and minute blockages in single acquisitions of the brain (top, middle) and heart (bottom) with substantially reduced risk of motion artifact and at less radiation dose to the patient.

Arterial and venous anatomy, as well as brain perfusion data, were captured in a volumetric acquisition composed of 256 slices, each 0.5-mm thick, with a total contrast injection of 45 cc. Red vessels represent the arterial phase, blue the venous in these brain images acquired with 12.8-cm coverage at Johns Hopkins Medicine.

The wide area single-rotation acquisition identifies areas of the brain vulnerable to stroke due to slow blood flow. Red area in brain perfusion image corresponds to high flow, blue indicates low, and yellow/green intermediate. The Toshiba prototype, the final version of which is scheduled to begin shipping commercially in 2008, instantly captures this information for the entire brain.

Volumetric acquisition of the heart shows hardened coronary arteries with cholesterol and plaque accumulation. The 12.8-cm image was acquired in a single heartbeat, eliminating the chance that irregular heartbeats will degrade a reconstruction of the data. The single rotation of the gantry reduces radiation exposure to the patient to as little as one-eighth to one-third of the dose necessary for scans done on a 64-slice CT, according to the Johns Hopkins staff. This is possible because the scanner does not require the overlapping slices that accompany helical scanning of the heart. (Provided by Drs. Kieran Murphy, Rich George, Al Lardo, and Joao Lima, Johns Hopkins University)