Respiratory gated multidetector computed tomography: applicable for diagnostic abdominal imaging?

To evaluate the ability and accuracy of a respiratory gated technique used with contrast enhanced MDCT of the upper abdomen with focus on diagnostic image quality and depiction of organs and major vessels.

Forty-five adult patients who were referred to our institution for follow-up dynamic contrast enhanced abdominal CT imaging were included in this study. Respiratory gated CT scans were performed with the use of a dedicated hardware. A multiphasic CT scan was performed for each patient. Respiratory gated images were obtained between early arterial and portal venous phases during free breathing. Images of respiratory gated (RG) and breathhold (BH) phases were compared qualitatively and quantitatively by two radiologists. Definitive statistical methods were used for evaluating the scoring data, while Mann Whitney U test was used for comparison. Statistical significance was accepted for p values <0.05.

Statistical significant difference was found for comparison of scores regarding luminal opacification and contoural integrity of intrahepatic vascular structures with scores of RG scans rated poor to moderate (e.g. 2.86+/-1.07 for luminal opacification of intrahepatic portal veins as well as border detectability) in comparison to scores of BH scans rated good to excellent (e.g. 1.37+/-1.31 for luminal opacification, 1.35+/-1.28 for border detectability of intrahepatic portal veins, p<0.001). Furthermore, statistical significant differences were found for general image noise levels (p<0.001).

Further technical advances of RG technique could enable routine use of this technique for selected patient groups.