Highlights
- •Barium-based internal shielding during maternal CTPA limits PE assessment.
- •AEC increases tube current over the region of barium filled stomach.
- •Although restricting scan length to the top of left hemidiaphragm may overcome such limitations, it is not ideal for assessing the entire lungs.
Abstract
Purpose
The purpose of our retrospective study was to assess the effect of barium sulfate
contrast medium on radiation dose and diagnostic quality of CT Pulmonary Angiography
(CTPA) in an in-vivo study of pregnant patients.
Methods
Our retrospective study included 33 pregnant patients who underwent CTPA to exclude
pulmonary embolism. The patients received oral 40% w/v barium solution just prior
to the acquisition of their planning radiograph. All CTPA were performed on 64-slice,
single-source CT scanners with AEC with noise index = 28.62–31.64 and the allowed
mA range of 100–450. However, only 5/33 patients had mA modulation (AEC 100–450 mA
range), while 28/33 patients had mA maxed out at the set maximum mA of 450 over the
entire scan range. We recorded CTDIvol (mGy), DLP (mGy.cm) and scan length. The same
information was recorded in weight-and scanner-matched, non-pregnant patients. Statistical
tests included descriptive data (median and interquartile range) and Mann-Whitney
test.
Results
There were no significant differences in CTDIvol and DLP between the barium and control
group patients (p > 0.1). The median mA below the diaphragm was significantly higher
in each patient with barium compared to the weight and scanner-matched patient without
barium. Evaluation of lung and subsegmental lower lobe pulmonary arteries was limited
in 85% barium group. Due to thin prospective section thickness (1.25 mm), most patients
were scanned at maximum allowed mA for AEC.
Conclusion
Use of AEC with thick barium in pregnant patients undergoing CTPA as an internal radioprotective
shield produces counterproductive artifacts and tube current increments.
Keywords
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Article info
Publication history
Published online: August 29, 2022
Accepted:
August 17,
2022
Received in revised form:
August 5,
2022
Received:
May 4,
2022
Identification
Copyright
© 2022 Associazione Italiana di Fisica Medica e Sanitaria. Published by Elsevier Ltd. All rights reserved.
