Author + information
- Christian Hamilton-Craig, MBBS⁎ (, )
- Martin Seltmann, MD,
- Dieter Ropers, MD and
- Stephan Achenbach, MD
- ↵⁎Department of Medical Imaging, The Prince Charles Hospital, Brisbane 4032, Queensland, Australia
A 77-year-old male presented with an inferior ST-segment elevation myocardial infarction. Coronary angiography revealed thrombotic occlusion of the right coronary artery (Fig. 1). Percutaneous intervention was unsuccessful, and imaging was requested to determine suitability for surgical revascularization.
Computed cardiac tomography (CT) was performed on day 4 post-infarction using a dual-source 128-slice CT scanner (Somatom Definition FLASH, Siemens Healthcare, Forchheim, Germany). Coronary imaging was performed with prospective electrocardiogram (ECG) gating, 100 kV, 0.28-s rotation time, pitch 0.9, 64-mm × 0.6-mm slice acquisition, B26f soft kernel reconstruction (Figs. 2A and 2B). A total of 100 ml of iodine contrast material (Ultravist 370, Bayer-Schering HealthCare, Berlin, Germany) was injected at a flow rate of 6 ml/s, followed by a 50-ml saline bolus. Delayed reimaging was performed at 12 min after the contrast bolus using a dual-energy CT protocol; retrospective ECG gating, pulse width 60% to 80%, tube A 100 kV at 165 mA, tube B 140 kV at 140 mA. Total radiation dose for both acquisitions was 4.8 mSv.
Images were reconstructed with a slice thickness of 0.75 mm each 0.5 mm, with a 5122 matrix and individually adapted field-of-view (FOV = 130 to 150 mm), using a dual-energy soft-tissue kernel (D30f), and displayed to assess the myocardium in short-axis views (Figs. 2A and 2B). Dual-energy iodine map and morphological delayed enhancement CT images were merged (Syngo DualEnergy, Siemens) to clearly demonstrate transmural inferior wall infarction with a high signal differential from infarcted to normal myocardium (Figs. 2C and 2D). A separate subendocardial infarct is also detected in the basal-lateral wall (Fig. 2C, arrowhead). The distribution and extent of infarction show striking similarity to the cardiac magnetic resonance images acquired 1 day later (Figs. 2E and 2F).
These images document the first use, to our knowledge, of dual-energy CT delayed enhancement myocardial viability imaging. Dual-energy CT harnesses the intrinsic variations in attenuation when iodine is exposed to beams of differing kV, made possible in this case by using dual-source technology (1). Delayed enhancement imaging exploits the similar myocardial washout kinetics of iodine to gadolinium, allowing imaging of infarcted myocardium in a similar manner to CMR (2).
Myocardial delayed enhancement imaging using dual-energy CT acquisition may provide a feasible alternative for myocardial viability assessment in patients with contraindications to magnetic resonance. Further research will define the accuracy and reproducibility of this technique.
Please note: The authors acknowledge Mr. Gerd Muschiol for assistance with image acquisition. Dr. Hamilton-Craig is funded by the National Heart Foundation of Australia and the Queensland International Fellowship. Dr. Ropers is on the Speakers' Bureau for Siemens Healthcare. Dr. Achenbach has received research grants and speaking honoraria from Siemens Healthcare and Bayer Schering Pharma. Dr. Seltmann has reported that he has no relationships to disclose.
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