Abstract
The objective of this study was to evaluate the utility of a low mA 1.5 pitch helical
versus conventional high mA conventional technique in abdominal computed tomography
(CT). Twenty-five patients who had both a conventional high mA (>300) and a 1.5 pitch
low mA (80–125) helical CT within 3 months were selected for inclusion in the study.
Patients were excluded who had a significant change in pathology between the two studies.
The other parameters (injection rate, contrast type and volume, and filming window/level)
were constant. The studies were randomized and blinded to five separate experienced
readers who graded the studies by a variety of normal anatomical structures and pathological
criteria. Overview questions also assessed noise, resolution, contrast, and overall
quality. The abdominal wall/retroperitoneum and hiatal hernias were statistically
better visualized on the conventional high mA studies. However, for all other normal
anatomical and pathological sites, there was equivalent or better visualization on
the helical versus the conventional CT examinations. The resolution of the helical
studies was graded statistically better than the high mA conventional CT scans as
was the amount of noise present on the images. While there was some advantage for
conventional high mA CT with respect to contrast enhancement and low contrast sensitivity,
these differences were not statistically significant. It appears from the data of
this study that a low mA technique in evaluating the abdomen may be a useful option
in performing routine abdominal CT. The radiation dose savings to the patient is significant
and there appears to be little degradation of image quality using a low mA 1.5 helical
versus mA conventional CT technique.
Keywords
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Article info
Publication history
Accepted:
October 1,
1996
Received:
August 1,
1996
Identification
Copyright
© 1998 Elsevier Science Inc. Published by Elsevier Inc. All rights reserved.
