Effect of increasing the sampling interval to 2 seconds on the radiation dose and accuracy of CT perfusion of the head and neck.

Abstract

PURPOSE:

To evaluate the effect of increasing the sampling interval from 1 second (1 image per second) to 2 seconds (1 image every 2 seconds) on computed tomographic (CT) perfusion (CTP) of head and neck tumors.

MATERIALS AND METHODS:

Twenty patients underwent CTP studies of head and neck tumors with images acquired in cine mode for 50 seconds using sampling interval of 1 second. Using deconvolution-based software, analysis of CTP was done with sampling interval of 1 second and then 2 seconds. Perfusion maps representing blood flow, blood volume, mean transit time, and permeability surface area product (PS) were obtained. Quantitative tumor CTP values were compared between the 2 sampling intervals. Two blinded radiologists compared the subjective quality of CTP maps using a 3-point scale between the 2 sampling intervals. Radiation dose parameters were recorded for the 2 sampling interval rates.

RESULTS:

No significant differences were observed between the means of the 4 perfusion parameters generated using both sampling intervals; all P >0.05. The 95% limits of agreement between the 2 sampling intervals were -65.9 to 48.1) mL/min per 100 g for blood flow, -3.6 to 3.1 mL/100 g for blood volume, -2.9 to 3.8 seconds for mean transit time, and -10.0 to 12.5 mL/min per 100 g for PS. There was no significant difference between the subjective quality scores of CTP maps obtained using the 2 sampling intervals; all P > 0.05. Radiation dose was halved when sampling interval increased from 1 to 2 seconds.

CONCLUSIONS:

Increasing the sampling interval rate to 1 image every 2 seconds does not compromise the image quality and has no significant effect on quantitative perfusion parameters of head and neck tumors. The radiation dose is halved.

• Authors: Ahmed M Tawfik, Ahmed A Razek, Galal Elhawary, Nihal M Batouty
• Journal: Journal of computer assisted tomography (J Comput Assist Tomogr) 2014 May-Jun Vol. 38 Issue 3 Pg. 469-73 ISSN: 1532-3145 [Electronic] United States
• PMID: 24651742 (Publication Type: Journal Article)

Topics

• Head and Neck Neoplasms (diagnostic imaging)
• Humans
• Perfusion Imaging (methods)
• Radiation Dosage
• Radiation Protection (methods)
• Radiographic Image Interpretation, Computer-Assisted (methods)
• Reproducibility of Results
• Sample Size
• Sensitivity and Specificity
• Tomography, X-Ray Computed (methods)