Clinical validation of dual-source dual-energy computed tomography (DECT) for coronary and valve imaging in patients undergoing trans-catheter aortic valve implantation (TAVI).
OBJECTIVE
To assess the validity of virtual non-contrast (VNC) reconstructions for coronary artery calcium (CACS) and aortic valve calcium scoring (AVCS) in patients undergoing trans-catheter aortic valve implantation (TAVI).


METHODS
Twenty-three consecutive TAVI patients underwent a three-step computed tomography (CCT) acquisition: (1) traditional CACS; (2) dual-energy (DE) CT coronary angiogram (CTCA); and (3) DE whole-body angiogram. Linear regression was used to model calcium scores generated from VNC images with traditional scores to derive a conversion factor [2.2 (95% CI: 1.97-2.58)]. The effective radiation dose for the TAVI protocol was compared to a standard control group. Bland-Altman analysis and weighted k-statistic were used to assess inter-method agreement for absolute score and risk centiles.


RESULTS
CACS and AVCS from VNC reconstructions correlated well with traditional scores (r = 0.94 and r = 0.86; both p < 0.0001). There was excellent agreement between VNC and non-contrast coronary calcium scores [mean difference -71.8 (95% limits of agreement -588.7 to 445.1)], with excellent risk stratification into risk centiles (k = 0.99). However, the agreement was weaker for the aortic valve [mean difference -210.6 (95% limits of agreement -1233.2 to 812)]. Interobserver variability was excellent for VNC CACS [mean difference of 6 (95% limits of agreement 134.1-122.1)], and AVCS [mean difference of -16.4 (95% limits of agreement 576 to -608.7)]. The effective doses for the DE TAVI protocol was 16.4% higher than standard TAVI protocol (22.7 versus 19.5 mSv, respectively) accounted for by the DE CTCA dose being 47.8% higher than that for a standard CTCA [9.9 (5.6-14.35) versus 6.7 (1.17-13.72) mSv; p < 0.01).


CONCLUSIONS
CACS and AVCS can be accurately quantified, and patients can be risk stratified using DECT VNC reconstructions. However, the dose from DE CTCA is significantly greater than the standard single-energy CTCA precluding the use of this technology in routine clinical practice.
Imperial College, London SW7 2AZ, UK.
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R
Mahoney
Department of Radiology, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK; Department of Cardiology, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK.
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CW
Pavitt
Physics Department, Royal Marsden Hospital, Fulham Road, London SW3 6JJ, UK.
D
D
Gordon
Physics Department, Royal Marsden Hospital, Fulham Road, London SW3 6JJ, UK.
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B
Park
Department of Radiology, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK; Faculty of Medicine, Imperial College, London SW7 2AZ, UK.
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MB
Rubens
Department of Radiology, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK; Department of Cardiology, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK; Faculty of Medicine, Imperial College, London SW7 2AZ, UK.
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ED
Nicol
Department of Radiology, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK; Faculty of Medicine, Imperial College, London SW7 2AZ, UK. Electronic address: s.padley@ic.ac.uk.
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SP
Padley
D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000000981:diagnostic imaging* / Q000601:surgery*; D002114:Calcinosis / Q000000981:diagnostic imaging*; D017023:Coronary Angiography / Q000379:methods*; D005260:Female; D006350:Heart Valve Prosthesis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods*; D051598:Whole Body Imaging / Q000379:methods