Coronary Artery Stent Evaluation Using a Vascular Model at 64-Detector Row CT: Comparison between Prospective and Retrospective ECG-Gated Axial Scans

Abstract

ObjectiveWe wanted to evaluate the performance of prospective electrocardiogram (ECG)-gated axial scans for assessing coronary stents as compared with retrospective ECG-gated helical scans.Materials and MethodsAs for a vascular model of the coronary artery, a tube of approximately 2.5-mm inner diameter was adopted and as for stents, three (Bx-Velocity, Express2, and Micro Driver) different kinds of stents were inserted into the tube. Both patent and stenotic models of coronary artery were made by instillating different attenuation (396 vs. 79 Hounsfield unit [HU]) of contrast medium within the tube in tube model. The models were scanned with two types of scan methods with a simulated ECG of 60 beats per minute and using display field of views (FOVs) of 9 and 18 cm. We evaluated the in-stent stenosis visually, and we measured the attenuation values and the diameter of the patent stent lumen.ResultsThe visualization of the stent lumen of the vascular models was improved with using the prospective ECG-gated axial scans and a 9-cm FOV. The inner diameters of the vascular models were underestimated with mean measurement errors of -1.10 to -1.36 mm. The measurement errors were smaller with using the prospective ECG-gated axial scans (Bx-Velocity and Express2, p < 0.0001; Micro Driver, p = 0.0004) and a 9-cm FOV (all stents: p < 0.0001), as compared with the other conditions, respectively. The luminal attenuation value was overestimated in each condition. For the luminal attenuation measurement, the use of prospective ECG-gated axial scans provided less measurement error compared with the retrospective ECG-gated helical scans (all stents: p < 0.0001), and the use of a 9-cm FOV tended to decrease the measurement error.ConclusionThe visualization of coronary stents is improved by the use of prospective ECG-gated axial scans and using a small FOV with reduced blooming artifacts and increased spatial resolution.

High-Definition Computed Tomography for Coronary Artery Stent Imaging: a Phantom Study

“…Consistent with previous studies ( 14 , 15 , 20 ), our study demonstrated that the measurements of coronary artery stent images from PTA acquisition is significantly better than that from RGH. There are two potential explanations of the artifact reductions by PTA scans.…”

“…The artificial lumen narrowing (ALN) was calculated with the following equation: ALN = (ISD - ISD measured )/ISD ( 14 , 15 ). The artificial attenuation increase (AAI) between in-stent and in-vessel were also calculated with the following equation: AAI = AV in-stent - AV in-vessel .…”

Evaluation of coronary artery in-stent restenosis with prospectively ECG-triggered axial CT angiography versus retrospective technique: a phantom study

“…All measurements were repeated three times and the mean of the measurements by two observers was calculated separately. Artificial lumen narrowing was calculated using the following equation [9,10]: artificial lumen narrowing=(inner stent diameter -visible lumen diameter )/inner stent diameter.…”

“…Although retrospective electrocardiographically (ECG)-gated helical (REH) scans are mainly used, with advances in technique, prospective ECG-triggered axial (PEA) scans allow a substantial reduction in radiation dose compared with REH scans (15 mSv reduced to 1.0-5 mSv) while having a possible advantage for in-stent restenosis imaging owing to the reduction of artefacts compared with REH scans [6][7][8][9][10]. Therefore, the purpose of our study was to clarify the influence of scan modes and tube voltage on the in-stent visibility, artificial lumen narrowing and lumen attenuation by using in-stent 50% and 75% restenosis vessel models.…”

Exploring the best monochromatic energy level in dual energy spectral imaging for coronary stents after percutaneous coronary intervention

“…In the CCTA image, the metal artifact of the scaffold has the effect of magnifying the scaffold. Meanwhile, the inner diameter and area of the scaffold cavity decrease, and the CT value of the scaffold increases 13 .…”