Imaging of the Left Atrial Appendage Before Occluder Device Placement: Evaluation of Virtual Monoenergetic Images in a Single-Bolus Dual-Phase Protocol. Issue 5 (18th September 2022)

• Record Type: Journal Article
• Authors: Laukamp, Kai Roman; Dastmalchian, Sara; Tandon, Yasmeen K.; Ciancibello, Leslie; Pennig, Lenhard; Lennartz, Simon; Al-Kindi, Sadeer; Rajagopalan, Sanjay; Bera, Kaustav; Hokamp, Nils Große; Gilkeson, Robert; Gupta, Amit
• Is Part Of: Journal of computer assisted tomography. Volume 46:Issue 5(2022)
• Page Start: 735
• Page End: 741
• Publication Date: 2022-09-18
• Subjects: left atrial appendage -- occluder device -- x-ray computed tomography -- spectral detector -- dual-energy CT -- AF - atrial fibrillation -- CNR - contrast-to-noise ratio -- CT - computed tomography -- CTDIvol - CT dose index -- DECT - dual-energy CT -- eGFR - estimated glomerular filtration rate -- LA - left atrium -- LAA - left atrial appendage -- ROI - region of interest -- SDCT -spectral detector CT -- SNR - signal-to-noise (SNR) -- TEE - transesophageal echocardiography -- VMI - virtual monoenergetic image; Tomography -- Periodicals; Tomography -- Periodicals; Tomography; Periodicals; 616.0757
• DOI: 10.1097/RCT.0000000000001330
• Languages: English
• ISSNs: 0363-8715

Abstract

Abstract : Purpose: Preimplantation cardiac computed tomography (CT) for assessment of the left atrial appendage (LAA) enables correct sizing of the device and the detection of contraindications, such as thrombi. In the arterial phase, distinction between false filling defects and true thrombi can be hampered by insufficient contrast medium distribution. A delayed scan can be used to further differentiate both conditions, but contrast in these acquisitions is relatively lower. In this study, we investigated whether virtual monoenergetic images (VMI) from dual-energy spectral detector CT (SDCT) can be used to enhance contrast and visualization in the delayed phase. Materials and Methods: Forty-nine patients receiving SDCT imaging of the LAA were retrospectively enrolled. The imaging protocol comprised dual-phase acquisitions with single-bolus contrast injection. Conventional images (CI) from both phases and 40-keV VMI from the delayed phase were reconstructed. Attenuation, signal-, and contrast-to-noise ratios (SNR/CNR) were calculated by placing regions-of-interest in the LAA, left atrium, and muscular portion of interventricular septum. Two radiologists subjectively evaluated conspicuity and homogeneity of contrast distribution within the LAA. Results: Contrast of the LAA decreased significantly in the delayed phase but was significantly improved by VMI, showing comparable attenuation, SNR, and CNR to CI from the arterial phase (attenuation/SNR/CNR, CI arterial phase: 266.0 ± 117.0 HU/14.2 ± 7.2/6.6 ± 3.9; CI-delayed phase: 107.6 ± 35.0 HU/5.9 ± 3.0/1.0 ± 1.0; VMI delayed phase: 260.3 ± 108.6 HU/18.2 ± 10.6/4.8 ± 3.4). The subjective reading confirmed the objective findings showing improved conspicuity and homogeneity in the delayed phase. Conclusions: The investigated single-bolus dual-phase acquisition protocol provided improved visualization of the LAA. Homogeneity of contrast media was higher in the delayed phase, while VMI maintained high contrast.