Purpose
The quality of a contrast CT scan depends on many parameters such as iodine delivery rate,
contrast concentration,
total iodine dose,
scan timing,
patient blood circulation,
patient size,
technical scan parameters etc.
[1-4]. A general consensus on the contrast injection protocol is difficult since thorough experimental data on the effect of these parameters on the contrast enhancement remains scarce.
The purpose of this study is to assess arterial enhancement on a porcine model for various concentrations of contrast media administered at a fixed iodine delivery...
Methods and Materials
Two Göttingen mini pigs (Ellegaard,
Dalmose,
Denmark) were used in this study,
with weight range33 to 41 kg (average 37.5 kg),and with an effective abdominal diameterranging from25.5 to 28.7 cm (average at 26.5),
which corresponds well to the equivalent abdominal diameter of an average 18 year old human adult (diameter of 29,2 cm,
[5]).
The minipigs received dynamic contrast CT scans in a 4 cm segment at hepatic level (Figure 1) with high time resolution (2 scans per second) during 120 s on a HD750...
Results
Figure 3 shows the mean enhancement curves,
averaged over all repeated scans of both pigs,
for the three injection protocols.
The CTmax and Δt>200HU values,
derived from the time enhancement curves,
are tabulated in table 2(a),
(b) and (c) for concentrations 320,
220 and 160 mg I/ml,
respectively.
A significantly (p<0.02) broader enhancement peak is observed for 160 mgI/ml (mean Δt>200HU= 16.3s) and 200 mgI/ml (Δt>200HU= 17.0s) compared to standard 320 mgI/ml (Δt>200HU= 11.7s).
Furthermore,
the data suggest an increase (p=0.053) in peak enhancement for...
Conclusion
Time enhancement curves allow a thorough investigation of contrast biodynamics in the arterial phase. Despitefixed iodine delivery rate andfixed total iodine dose,
contrast concentration has an impact on arterial enhancement.A lower iodine concentration injected at a higher speed results in a broader peak,
which relaxes the timing of the acquisition in CT angiography studies,
and in an increased arterial contrast enhancement.
References
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