Retrospective image-based gating of intracoronary optical coherence tomography: implications for quantitative analysis.

Aims: Images acquired of coronary vessels during a pullback of time-domain optical coherence tomography (OCT) are influenced by the dynamics of the heart. This study explores the feasibility of applying an in-house developed retrospective image-based gating method for OCT and the influence of catheter dislocation and luminal changes during the cardiac cycle on the outcome of quantitative OCT (QOCT).

Methods And Results: The gating method was developed using Matlab (The Mathworks, Natick, MA, USA) and operates in a fully-automatic manner.

Monitoring in vivo absorption of a drug-eluting bioabsorbable stent with intravascular ultrasound-derived parameters a feasibility study.

Objectives: The aim of this study was to investigate the feasibility of using quantitative differential echogenicity to monitor the in vivo absorption process of a drug-eluting poly-l-lactic-acid (PLLA) bioabsorbable stent (BVS, Abbott Vascular, Santa Clara, California).

Background: A new bioabsorbable, balloon-expanded coronary stent was recently evaluated in a first-in-man study. Little is known about the absorption process in vivo in diseased human coronary arteries.

Compositional volumetry of non-calcified coronary plaques by multislice computed tomography: an ex vivo feasibility study.

Aims: Non-invasive quantitative compositional analysis of coronary plaque would be a major advantage to study coronary artery disease. This study explores the application to use the Hounsfield units (HU) distribution of coronary plaques imaged by multislice computed tomography-coronary angiography (MSCT-CA).

Methods And Results: A dedicated computer-assisted method was developed to measure the HU distribution within a coronary plaque by MSCT-CA.

Lumen enhancement influences absolute noncalcific plaque density on multislice computed tomography coronary angiography: ex-vivo validation and in-vivo demonstration.

Aim: The purpose of this study was to define the in-vitro and in-vivo effects of intracoronary enhancement on the absolute density values of coronary plaques during multislice computed tomography.

Methods: We studied seven ex-vivo left coronary artery specimens surrounded by olive oil and filled with isotonic saline and four solutions with decreasing dilutions of contrast material: control (isotonic saline), 1/200, 1/80, 1/50, and 1/20. The multislice computed tomography protocol was: slice/collimation 32 x 2 x 0.

Coronary calcium significantly affects quantitative analysis of coronary ultrasound: importance for atherosclerosis progression/regression studies.

Background: Coronary atherosclerosis is a dynamic process, which progresses differently in coronary segments containing noncalcified or calcified plaques. This may have implications for the study of the effects of therapy on progression/regression.

Objective: To test this hypothesis, we performed a post-hoc analysis on data of a randomized trial in which perindopril treatment was compared with placebo on progression/regression of atherosclerosis with regard to the degree of calcification.

Fully automatic three-dimensional quantitative analysis of intracoronary optical coherence tomography: method and Validation.

Objectives And Background: Quantitative analysis of intracoronary optical coherence tomography (OCT) image data (QOCT) is currently performed by a time-consuming manual contour tracing process in individual OCT images acquired during a pullback procedure (frame-based method). To get an efficient quantitative analysis process, we developed a fully automatic three-dimensional (3D) lumen contour detection method and evaluated the results against those derived by expert human observers.

Methods: The method was developed using Matlab (The Mathworks, Natick, MA).

Quantification of coronary plaque by 64-slice computed tomography: a comparison with quantitative intracoronary ultrasound.

Background: Noninvasive assessment of coronary atherosclerotic plaque may be useful for risk stratification and treatment of atherosclerosis.

Materials And Methods: We studied 47 patients to investigate the accuracy of coronary plaque volume measurement acquired with 64-slice multislice computed tomography (MSCT), using newly developed quantification software, when compared with quantitative intracoronary ultrasound (QCU). Quantitative MSCT coronary angiography (QMSCT-CA) was performed to determine plaque volume for a matched region of interest (regional plaque burden) and in significant plaque defined as a plaque with > or =50% area obstruction in QCU, and compared with QCU.

A novel approach for quantitative analysis of intracoronary optical coherence tomography: high inter-observer agreement with computer-assisted contour detection.

Objective: This study aims to examine observer-related variability of quantitative optical coherence tomography (OCT) derived measurements from both in vitro and in vivo pullback data.

Background: Intravascular OCT is a new imaging modality using infrared light and offering 10 times higher image resolution (15 microm) compared to intravascular ultrasound. The quantitative analysis of in vivo intracoronary OCT imaging is complicated by the presence of blood, motion artifacts and the large quantity of information that has to be processed.

Three-dimensional and quantitative analysis of atherosclerotic plaque composition by automated differential echogenicity.

Objective: To validate automated and quantitative three-dimensional analysis of coronary plaque composition using intracoronary ultrasound (ICUS).

Background: ICUS displays different tissue components based on their acoustic properties in 256 grey-levels. We hypothesised that computer-assisted image analysis (differential echogenicity) would permit automated quantification of several tissue components in atherosclerotic plaques.

Reproducible coronary plaque quantification by multislice computed tomography.

Background: The aim of this study was to investigate reproducibility and accuracy of computer-assisted coronary plaque measurements by multislice computed tomography coronary angiography (QMSCT-CA).

Methods And Results: Forty-eight patients undergoing MSCT-CA and coronary arteriography for symptomatic coronary artery disease and quantitative intravascular ultrasound (IVUS, QCU) were examined. Two investigators performed the QMSCT-CA twice and a third investigator performed the QCU, all blinded for each other's results.

Non-invasive visualization of coronary atherosclerosis: state-of-art.

Coronary artery disease remains the leading cause of death in the Western world. Non-invasive coronary artery imaging challenges any diagnostic modality because the coronary arteries are small and tortuous, whereas cardiac contraction and respiration cause motion artifacts. Therefore, non-invasive coronary imaging requires high spatial and temporal resolution.

Influence of convolution filtering on coronary plaque attenuation values: observations in an ex vivo model of multislice computed tomography coronary angiography.

Attenuation variability (measured in Hounsfield Units, HU) of human coronary plaques using multislice computed tomography (MSCT) was evaluated in an ex vivo model with increasing convolution kernels. MSCT was performed in seven ex vivo left coronary arteries sunk into oil followingthe instillation of saline (1/infinity) and a 1/50 solution of contrast material (400 mgI/ml iomeprol). Scan parameters were: slices/collimation, 16/0.

Influence of increasing convolution kernel filtering on plaque imaging with multislice CT using an ex-vivo model of coronary angiography.

Purpose: To assess the variability in attenuation of coronary plaques with multislice CT-angiography (MSCT-CA) in an ex-vivo model with varying convolution kernels.

Materials And Methods: MSCT-CA (Sensation 16, Siemens) was performed in three ex-vivo left coronary arteries after instillation of contrast material solution (Iomeprol 400 mgI/ml, dilution: 1/80). The specimens were placed in oil to simulate epicardial fat.

Influence of intracoronary attenuation on coronary plaque measurements using multislice computed tomography: observations in an ex vivo model of coronary computed tomography angiography.

Assessment of attenuation (measured in Hounsfield units, HU) of human coronary plaques was performed using multislice computed tomography (MSCT) in an ex vivo model. In three ex vivo specimens of left coronary arteries in oil, MSCT was performed after intracoronary injection of four solutions of contrast material (400 mgI/ml iomeprol). The four solutions were diluted as follows: 1/infinity, 1/200, 1/80, and 1/20.

Incomplete stent apposition after implantation of paclitaxel-eluting stents or bare metal stents: insights from the randomized TAXUS II trial.

Background: The clinical impact of late incomplete stent apposition (ISA) for drug-eluting stents is unknown. We sought to prospectively investigate the incidence and extent of ISA after the procedure and at 6-month follow-up of paclitaxel-eluting stents in comparison with bare metal stents (BMS) and survey the clinical significance of ISA over a period of 12 months.

Methods And Results: TAXUS II was a randomized, double-blind study with 536 patients in 2 consecutive cohorts comparing slow-release (SR; 131 patients) and moderate-release (MR; 135 patients) paclitaxel-eluting stents with BMS (270 patients).

Adjustment method for mechanical Boston scientific corporation 30 MHz intravascular ultrasound catheters connected to a Clearview console. Mechanical 30 MHz IVUS catheter adjustment.

Intracoronary ultrasound (ICUS) is often used in studies evaluating new interventional techniques. It is important that quantitative measurements performed with various ICUS imaging equipment and materials are comparable. During evaluation of quantitative coronary ultrasound (QCU) software, it appeared that Boston Scientific Corporation (BSC) 30 MHz catheters connected to a Clearview ultrasound console showed smaller dimensions of an in vitro phantom model than expected.

Retrospective image-based gating of intracoronary ultrasound images for improved quantitative analysis: the intelligate method.

Quantitative analysis of intracoronary ultrasound (ICUS) studies is performed on a series of tomographic cross-sectional ICUS images acquired during a motorized 0.5 mm/sec catheter pullback. Catheter displacement in the vascular lumen during the cardiac cycle causes an anatomically shuffled ICUS study, which results in a sawtooth-shaped appearance of the coronary segment in longitudinal reconstructed views in quantitative coronary ultrasound software packages.