320-row CT transcatheter aortic valve replacement planning with a single reduced contrast media bolus injection

Abstract

ObjectiveTo reduce the iodine load required for CT Transcatheter Aortic Valve Replacement (TAVR) planning on a 320-row scanner by acquiring the two CT TAVR steps (ECG-gated aortic root CTA and non-gated aorto-ilio-femoral CTA) within a single contrast media bolus injection.Methods50 consecutive patients (82.6±6.9 years; 56% female) were prospectively enrolled and underwent a TAVR planning using a 320-row CT, with ECG-gated aortic root CTA immediately followed by a non-gated aorto-iliac acquisition, all within a single bolus of 40-70mL of Iohexol 350mgI/mL. The Iodine load, image quality, SNR, CNR and radiation dose were compared using a Mann-Whitney test to that of 24 consecutive patients (84.3±4.8 years, 58% female) previously imaged on a 64-row scanner with a conventional two-step protocol.ResultsIodine load was reduced by 44%. All examinations were of diagnostic quality, with improvement of the aortic root CTA image quality (4.9±0.3 versus 4.6±0.5, p<0.01) and a non-significant decrease of the aorto-iliac CTA image quality (4.7±0.6 versus 4.9±0.3, p = 0.07). SNR and CNR were significantly improved in the aortic root CTA (14.0±5.3 and 10.4±4.5 versus 10.3±4.2 and 6.8±3.3, p<0.01 for both) and non-significantly higher in the aorto-iliac CTA (16.5±8.0 and 14.1±7.9 versus 14.7±5.5 and 12.5±5.0, p = 0.42 and p = 0.66). Total radiation dose was reduced by 32%.Conclusion320-row CT scanner enables a 44% reduction of iodine load in TAVR planning, while maintaining excellent aorto-ilio-femoral arterial enhancement and lowering radiation dose.

Periprocedural Predictors of New-Onset Conduction Abnormalities After Transcatheter Aortic Valve Replacement

“…The aortic root CT was acquired in volume mode using a retrospective ECG-gated acquisition and the following CT parameters: 16 cm width, 100 kV, gantry rotation time of 0.275s, auto-mA maxed at 300, acquisition over 1 heartbeat. 16 Acquisition was obtained after a bolus injection of 50-70 mL of iomeprol 400 mg/mL (Iomeron ® , Bracco, Italy), using an automatic power injector at a rate of 3.5 mL/s, followed by a 30-mL saline chaser at a rate of 3 mL/s. The acquisition was triggered using a bolus-tracking technique with the region of interest positioned in the descending thoracic aorta and a 180 Hounsfield units threshold.…”

Clinical Applications of Wide-Detector CT Scanners for Cardiothoracic Imaging: An Update

“…This separate acquisition approach requires the injection of two separate boluses of the contrast material, resulting in the administration of a considerable amount of iodine. However, most TAVI candidates are elderly patients who frequently have compromised renal function (80)(81)(82). Moreover, accurate measurement of the aortic root annulus maximum size is critical for TAVI planning; thus, image acquisition with retrospective ECG gating to cover the entire cardiac cycle should be considered (78).…”

“…Moreover, accurate measurement of the aortic root annulus maximum size is critical for TAVI planning; thus, image acquisition with retrospective ECG gating to cover the entire cardiac cycle should be considered (78). Therefore, the application of the prospective ultra-high-pitch mode with dual-source scanners seems inappropriate for TAVI planning (78,82).…”

“…Many authors have suggested various acquisition protocols for TAVI to reduce the contrast material volume https://doi.org/10.3348/kjr.2019.0327 kjronline.org and radiation dose using the wide-detector CT scanner (73)(74)(75), and the suggested methods could be roughly divided into two types: 1) axial ECG-gated volume acquisition for the aortic root and heart followed by ungated helical acquisition for the abdomen and pelvis (82,83) and 2) axial ECG-gated volume acquisition for the aortic root and heart followed by three or four ungated volume acquisitions for the abdomen and pelvis (84). According to previous studies, wide-detector CT scanners enable 30-44% reduction in the iodine load and 32-48% reduction in the radiation dose in TAVI planning, while maintaining or providing better image quality than that of the conventional protocol using 64-detector-row CT scanners (82,84).…”

Computed tomography and magnetic resonance imaging assessment of aortic valve stenosis: an update

“…1-7) [1][2][3][4][5][6][7][8]. Recent developments in CT enable simultaneous evaluation of the coronary arteries, aorta, proximal lower extremity arteries CT and MRI of aortic valve stenosis with the use of smaller contrast amount and lower radiation dose than before [9][10][11][12][13][14][15][16][17]. A wide-coverage (256-or 320-slice) detector design or high pitch dual-source CT enables a fast scan covering the aorta, coronary, and proximal femoral arteries ( Fig.…”