Rofo 2013; 185(2): 128-135
DOI: 10.1055/s-0032-1325603
Experimentielle Radiologie
© Georg Thieme Verlag KG Stuttgart · New York

Carbon Dioxide-Contrasted Computed Tomography Angiography: High Pitch Protocols and Adapted Injection Parameters Improve Imaging Quality

Kohlendioxid-kontrastierte computertomografische Angiografie: Protokolle mit hohem Pitch und angepassten Injektionsparametern verbessern die Bildqualität
T. Penzkofer
1   Department of Diagnostic and Interventional Radiology, RWTH Aachen University Hospital, Aachen, Germany
2   Surgical Planning Laboratory, Department of Radiology, Brigham and Women‘s Hospital, Harvard Medical School, Boston, USA
3   Applied Medical Engineering, Helmholtz-Institute Aachen, RWTH Aachen University Hospital, Aachen, Germany
,
K. Slebocki
1   Department of Diagnostic and Interventional Radiology, RWTH Aachen University Hospital, Aachen, Germany
,
J. Grommes
4   European Vascular Center Aachen-Maastricht, Department of Vascular Surgery, RWTH Aachen University Hospital, Aachen, Germany
5   Department of Surgery, Maastricht University Medical Center, Maastricht, The Netherlands
,
P. Bruners
1   Department of Diagnostic and Interventional Radiology, RWTH Aachen University Hospital, Aachen, Germany
3   Applied Medical Engineering, Helmholtz-Institute Aachen, RWTH Aachen University Hospital, Aachen, Germany
,
P. P. Isfort
1   Department of Diagnostic and Interventional Radiology, RWTH Aachen University Hospital, Aachen, Germany
3   Applied Medical Engineering, Helmholtz-Institute Aachen, RWTH Aachen University Hospital, Aachen, Germany
,
N. Heussen
6   Department of Medical Statistics, Medical Faculty, RWTH Aachen University, Aachen, Germany
,
T. Schmitz-Rode
3   Applied Medical Engineering, Helmholtz-Institute Aachen, RWTH Aachen University Hospital, Aachen, Germany
,
C. K. Kuhl
1   Department of Diagnostic and Interventional Radiology, RWTH Aachen University Hospital, Aachen, Germany
,
S. Langer
4   European Vascular Center Aachen-Maastricht, Department of Vascular Surgery, RWTH Aachen University Hospital, Aachen, Germany
5   Department of Surgery, Maastricht University Medical Center, Maastricht, The Netherlands
,
A. H. Mahnken
1   Department of Diagnostic and Interventional Radiology, RWTH Aachen University Hospital, Aachen, Germany
3   Applied Medical Engineering, Helmholtz-Institute Aachen, RWTH Aachen University Hospital, Aachen, Germany
› Author Affiliations
Further Information

Publication History

06 July 2012

28 September 2012

Publication Date:
29 November 2012 (online)

Abstract

Purpose: To systematically investigate the impact of image acquisition and contrast injection parameters for CO2-enhanced CT angiography (CTA) of the aorto-iliac and peripheral arteries in a pig model using commercially available equipment. The aim was to establish an imaging protocol that is ready for use in human subjects.

Materials and Methods: Three domestic swine underwent CO2-CTA with varying injection parameters: pitch (1.0, 3.0), injection pressure (0.7 bar, 1.0 bar, 1.3 bar) and scan delay (2 s, 4 s, 6 s). Objective (vessel diameter) and subjective (image quality) parameters and applied radiation doses were systematically evaluated. To ensure clinical applicability of the setting, only approved catheters/injectors and standard injection parameters were evaluated.

Results: The image quality scores were superior and the vessel diameter was larger with high pitch in comparison to standard pitch (diameters: 4.7 ± 2.0 mm vs. 3.6 ± 2.1 mm, p = 0.0040, scores: 2.6 ± 1.1 vs. 2.0 ± 1.1, p = 0.0038). High injection pressure (1.3 bar) improved the image quality as assessed by subjective and objective ratings (diameters: 3.6 ± 2.0 mm, 4.0 ± 2.1 mm and 4.6 ± 2.1 mm, for 0.7, 1.0 and 1.3 bar, p-values ≤ 0.0052, scores: 1.9 ± 1.1, 2.3 ± 1.1 and 2.7 ± 1.2, p-values ≤ 0.0017), the same was observed for a shorter injection delay (diameters: 3.5 ± 2.0 mm, 4.2 ± 2.1 mm and 4.8 ± 2.1 mm, for 6 s, 4 s, and 2 s, p ≤ 0.0022, scores: 1.9 ± 1.1, 2.3 ± 1.1 and 2.7 ± 1.1, p-values ≤ 0.0013). The dose length products were 239 ± 47 mGycm (high pitch) and 565 ± 63 mGycm (standard pitch, p-values < 0.0001).

Conclusion: A higher pitch, shorter delay and higher injection pressure improve image quality in CO2-enhanced CTA. Since commercially available, clinically approved equipment was used. The protocol is now ready for use in human subjects.

Zusammenfassung

Ziel: Es sollen in einem klinisch zugelassenen Aufbau der Einfluss der Bildgebungs- und Injektionsparameter auf die computertomografische (CT) Kohlendioxid(CO2)-kontrastierte Becken-Bein-Angiografie (CO2-CTA) im Tiermodell untersucht werden. Ziel ist, ein Bildgebungsprotokoll zu etablieren, das für den Einsatz im Menschen geeignet ist.

Material und Methoden: In 3 Hausschweinen wurden CO2-CTAs durchgeführt, wobei der Pitch (1,0, 3,0), der Injektionsdruck (0,7 bar, 1,0 bar, 1,3 bar) und die Scanverzögerung (2 s, 4 s, 6 s) systematisch variiert wurden. Objektive (Gefäßdurchmesser) und subjektive (Bildqualität) Kriterien sowie die applizierte Strahlendosis wurden evaluiert. Um eine klinische Einsetzbarkeit der entwickelten Protokolle zu gewährleisten, wurden nur zugelassene Interventionsmaterialien und Injektionsparameter untersucht.

Ergebnisse: Die Bildqualität war besser und die Gefäßdurchmesser größer, wenn Untersuchungsprotokolle mit hohem Pitch verwendet wurden (Durchmesser: 4,7 ± 2,0 mm gegenüber 3,6 ± 2,1 mm, p = 0,0040, Bildqualität (Skala von 1 – 4): 2,6 ± 1,1 vs. 2,0 ± 1,1, p = 0,0038). Höherer Injektionsdruck (1,3 bar) verbesserte ebenfalls die subjektiven und objektiven Bewertungsparameter (Gefäßdurchmesser: 3,6 ± 2,0 mm, 4,0 ± 2,1 mm und 4,6 ± 2,1 mm, jeweils für 0,7, 1,0 und 1,3 bar, p-Werte ≤ 0,0052, Bildqualität: 1,9 ± 1,1, 2,3 ± 1,1 und 2,7 ± 1,2, p-Werte ≤ 0,0017), ähnliches war für eine kürzere Scanverzögerung feststellbar (Durchmesser: 3,5 ± 2,0 mm, 4,2 ± 2,1 mm und 4,8 ± 2,1 mm, für 6 s, 4 s, und 2 s, p ≤ 0,0022, Bildqualität: 1,9 ± 1,1, 2,3 ± 1,1 und 2,7 ± 1,1, p-Werte ≤ 0,0013).

Schlussfolgerung: Höherer Pitch, kürzere Scanverzögerung und höherer Injektionsdruck verbessern die Bildqualität in der CO2-CTA. Durch die Verwendung von zugelassenen Materialien ist das vorliegende Protokoll nun auf den Menschen übertragbar.

 
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