Virtual Monoenergetic Images (VMI+) in Dual-Source Dual-Energy CT Venography (DSDE-CTV) of the Lower Extremity Prior to Coronary Artery Bypass Graft (CABG): A Feasibility Study

Jonas Schmoee; Timm Dirrichs; Kerstin Fehrenbacher; Eric Tietz; Felix Hardt; Michael Schmid; Robin Fabian Gohmann; Sebastian Daniel Reinartz

doi:10.1016/j.acra.2019.11.005

Virtual Monoenergetic Images (VMI+) in Dual-Source Dual-Energy CT Venography (DSDE-CTV) of the Lower Extremity Prior to Coronary Artery Bypass Graft (CABG): A Feasibility Study

Acad Radiol. 2020 Sep;27(9):1249-1254. doi: 10.1016/j.acra.2019.11.005. Epub 2019 Dec 13.

Authors

Jonas Schmoee¹, Timm Dirrichs², Kerstin Fehrenbacher², Eric Tietz², Felix Hardt³, Michael Schmid⁴, Robin Fabian Gohmann⁵, Sebastian Daniel Reinartz²

Affiliations

¹ Department of Diagnostic and Interventional Radiology, University Hospital, RWTH Aachen University, Pauwelsstr. 30, 52074 Aachen, Germany. Electronic address: jschmoee@ukaachen.de.
² Department of Diagnostic and Interventional Radiology, University Hospital, RWTH Aachen University, Pauwelsstr. 30, 52074 Aachen, Germany.
³ University Hospital, RWTH Aachen University, Aachen, Germany.
⁴ Department of Cardiac, Thoracic and Vascular Surgery, University Hospital, RWTH Aachen University, Aachen, Germany.
⁵ Department of Diagnostic and Interventional Radiology, University Hospital, RWTH Aachen University, Pauwelsstr. 30, 52074 Aachen, Germany; Department of Diagnostic and Interventional Radiology, Heart Center Leipzig, Leipzig, Germany.

PMID: 31843393
DOI: 10.1016/j.acra.2019.11.005

Abstract

Rationale and objectives: To evaluate the image quality and suitability of Dual-Source Dual-Energy CT venography (DSDE-CTV) with asynchronous virtual monoenergetic images (VMI+) of the entire lower extremity in the context of pre-surgical assessment of complex cases prior to coronary bypass graft as a feasibility study.

Materials and methods: Fifteen consecutive patients, consisting of 5 females and 10 males with an average age of 52 ± 17 years underwent DSDE-CTV from the pubic symphysis to the ankles after intravenous injection of an iodinated contrast medium. DSDE-CTV was acquired with tube voltages of 80 kVp and sn140 kVp. Single spectrum images (A - 80 kVp; B - 140 kVp) as well as a linearly blended mixed data set (M_0.6) were reconstructed. By postprocessing, an VMI+ dataset at 40 keV was generated. Objective image quality parameters of the deep and superficial veins of thigh, knee, and calves were measured separately for each location. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Additionally, subjective image quality was assessed independently by two radiologists.

Results: Mean vascular attenuation was 73.9 ± 17.8 HU at B, 113.7 ± 42.2 HU at M_0.6, 119.4 ± 45.5 HU at A, and 201.0 ± 89.7 HU at VMI+. Mean CNR was 6.7 ± 2.0 at 140 keV, 9.25 ± 2.3 in the M_0.6 datasets, 8.7 ± 3.0 at 80 keV, and 12.9 ± 4.3 at 40 keV. Attenuation values were approximately doubled when compared to the reference standard (M_0.6) with significantly improved SNR and CNR (p < 0.05). Subjective image quality scores were highest for VMI+ datasets (4.1 ± 0.5) and lowest for B datasets (2.3 ± 0.37), however differences between VMI+ datasets and M_0.6 datasets did not reach statistical significance.

Conclusion: Postprocessing of dual-energy CTV with VMI+ significantly increases attenuation of veins and markedly improves SNR and CNR values, thereby improving the diagnostic quality of CTV for the evaluation of deep and superficial veins of the entire lower limb prior to coronary bypass graft.

Keywords: Computed tomography angiography/methods; Dual-energy; Multidetector computed tomography/methods; Phlebography; Phlebography/methods.

MeSH terms

Adult
Aged
Animals
Cattle
Coronary Artery Bypass
Feasibility Studies
Female
Humans
Lower Extremity / diagnostic imaging
Male
Middle Aged
Phlebography
Radiographic Image Interpretation, Computer-Assisted
Radiography, Dual-Energy Scanned Projection*
Retrospective Studies
Signal-To-Noise Ratio