Pitfalls in image reconstruction of helical CT angiography: an experimental study

This study was undertaken to evaluate the effects of the object related fac tors: background tissue and the direction of vessels on the morphological r eproducibility of helical CT angiography. Cylindrical tubes filled with a d iluted contrast medium were prepared to obtain vascular phantoms. The scan was performed within various background tissues. For the evaluation of the direction of the vessels, two types of vascular phantoms were prepared. The phantoms were scanned by varying beam collimations and scan pitches. Recon structed CT images were markedly affected by the background tissue. The rec onstructed images were also affected by the direction of vessels. (C) 1999 Elsevier Science Ltd. All rights reserved.