Jouke Dijkstra

Quantitative coronary ultrasound: state of the art

Intravascular Ultrasound (IVUS) provides real-time high resolution images of the arterial wall. By performing a three-dimensional reconstruction, it permits an advanced assessment of the vessel, lumen and wall morphology. Recently, the straight stacking of the IVUS images has been extended by a geometrically correct orientation of the images in 3D space, using biplane angiographic images. Quantification of IVUS images, both in 2D and 3D, requires segmentation of the images. Automated segmentation of IVUS images for quantitative analysis reduces the required time and the subjectivity of boundary tracing. Different segmentation approaches for 2D and 3D IVUS are discussed, including the commercially available packages for analysis of IVUS images. Furthermore different approaches for the 3D reconstruction including the use of biplane angiographic images are discussed. This chapters finishes with a discussion about the future directions of IVUS including the developments in the area of RF-data analysis and the developments of new devices.

Precise Anatomic Localization of Accumulated Lipids in Mfp2 Deficient Murine Brains Through Automated Registration of SIMS Images to the Allen Brain Atlas.

AbstractMass spectrometry imaging (MSI) is a powerful tool for the molecular characterization of specific tissue regions. Histochemical staining provides anatomic information complementary to MSI data. The combination of both modalities has been proven to be beneficial. However, direct comparison of histology based and mass spectrometry-based molecular images can become problematic because of potential tissue damages or changes caused by different sample preparation. Curated atlases such as the Allen Brain Atlas (ABA) offer a collection of highly detailed and standardized anatomic information. Direct comparison of MSI brain data to the ABA allows for conclusions to be drawn on precise anatomic localization of the molecular signal. Here we applied secondary ion mass spectrometry imaging at high spatial resolution to study brains of knock-out mouse models with impaired peroxisomal β-oxidation. Murine models were lacking D-multifunctional protein (MFP2), which is involved in degradation of very long chain fatty acids. SIMS imaging revealed deposits of fatty acids within distinct brain regions. Manual comparison of the MSI data with the histologic stains did not allow for an unequivocal anatomic identification of the fatty acids rich regions. We further employed an automated pipeline for co-registration of the SIMS data to the ABA. The registration enabled precise anatomic annotation of the brain structures with the revealed lipid deposits. The precise anatomic localization allowed for a deeper insight into the pathology of Mfp2 deficient mouse models. Graphical Abstractᅟ

Current and future developments in QCA and image fusion with IVUS

Although quantitative coronary arteriography (QCA) has been around now for quite some time, research and development continue to take place along several directions. First of all, the imaging medium has changed from the traditional 35 mm analog cinefilm to the digital world with the CD-R as the preferred carrier. This required adaptations of the basic contour detection algorithms. Stimulated by these same changes, digital review stations or DICOM-Viewers have been developed. In addition, third-generation QCA algorithms have been designed and implemented, and applied to quantitate complex morphology and radiopaque stents.

TCT-29 Performance and healing patterns after implantation of a novel sirolimus eluting bioresorbable scaffold. Six-month follow-up by optical coherence tomography in the FANTOM II study

The Fantom fully bioresorbable scaffold (Reva Medical, Inc., San Diego) features a polycarbonate polymer platform with covalently bound iodine for increased radiopacity, has a strut thickness of 125 μm, full degradation within 12-18 months and complete absorption within 36-42 months. Here we report

In vivo reconstruction of coronary artery and bioresorbable stents from intracoronary optical coherence tomography.

The implantation of bioresorbable scaffolds (BRS) alters the local hemodynamic environment. Computational fluid dynamics (CFD) allows evaluation of local flow pattern, shear stress (SS) and Pressure_distal/ Pressure_approximal (Pd/Pa). The accuracy of CFD results relies to a great extent on the reconstruction of the 3D geometrical model. The aim of this study was to develop a new approach for in vivo reconstruction of coronary tree and BRS by fusion of Optical Coherence Tomography (OCT) and X-ray angiography. Ten patients enrolled in the BIFSORB pilot study with BRS implanted in coronary bifurcations were included for analysis. All patients underwent OCT of the target vessel after BRS implantation in the main vessel. Coronary 3D reconstruction was performed creating two geometrical models: one was angiography model and the other was OCT model with the implanted BRS. CFD analysis was performed separately on these two models. The main vessel was divided into portions of 0.15 mm length and 0.15mm arc width for point-perpoint comparison of SS between the two models. Reconstruction of the implanted BRS in naturally bent shape was successful in all cases. SS was compared in the matched 205463 portions of the two models. The divergence of shear stress was higher in the OCT model (mean±SD: 2.27 ± 3.95 Pa, maximum: 142.48 Pa) than that in the angiography model (mean±SD: 2.05 ± 3.12 Pa, maximum: 83.63 Pa). Pd/Pa values were lower in the OCT model than in the angiography model for both main vessels and side branches (mean±SD: 0.979 ± 0.009 versus 0.984 ± 0.011, and 0.951 ± 0.068 versus 0.966 ± 0.051). Reconstruction of BRS in naturally bent shape after implantation is feasible. It allows detailed analysis of local flow pattern, including shear stress and Pd/Pa in vivo.

TCT-423 Adaptable strut contour analysis in scaffold evaluation by optical coherence tomography. Validation of the FANTOM II study analysis by micro-CT, bench test and in-vivo

RESULTS A total of 207 patients with at least one SV were included in this analysis. Mean follow-up time was 22.4 months 14.9 with 85.8 % of patients having at least 1 year of follow-up. Clinical presentation of pts. (72.4% male, mean age 58.5 11.7 years, 16.4% diabetics, 25.6% with previous PCI and/or CABG) was ACS in 55.1%. Multivessel treatment was perfomed in 17,9% (37 pz). Mean lesion length by QCA was 23.7 11.0 mm and mean RVD was 2.2 0.3 mm with 14.5% of moderate/sever calcification lesions and 19.8 % of bifurcation treatment. Pre-dilatation was performed in 93.2% and post-dilatation in 57.9%. The mean scaffold length was 28.1 15.0 mm with 30.9% of cases using overlapping scaffolds. OCT or IVUS was used in 26.0%. Device success was 99.0% (failure to deliver in 2 pts). Over the entire follow-up period, death occurred in 3.4 % (7/207), myocardial infarction (MI) in 5.3% (11/207), target lesion revascularization in 7.2 % (15/207), target vessel revascularization (TVR) in 8.2% (17/207), non-target vessel revascularization in 2.9 (6/207) %. Overall MACE (death, MI, TVR) rate was 12.0% (25/207). Definite stent thrombosis (ST) occurred in 6 pts. (2.9%), of whom early ST occurred in 4 pts and late ST in 2 pts.

Quantitative Cardiovascular Image Analysis: Current Status and what are Realistic Expectations for the Future?

Cardiology is typically an image oriented specialty. Single still images, but much more so dynamic and increasingly three-dimensional image sequences, play a major role in clinical decision making and clinical research trials. Of major interest is always the state of the coronary arteries and of the left ventricular function. In this chapter an overview is given of the various quantitative approaches using automated edge detection techniques which have been developed in our departments to: 1) assess the severity of disease of coronary obstructions from x-ray arteriography and intravascular ultrasound; and 2) assess the global and regional left ventricular function from x-ray angiography, echocardiography and magnetic resonance (MR) imaging. Also, the possibilities of MR flow velocity mapping are presented. In addition, for each modality and application a short description is given of the future developments and expectations. Finally, it is recognized that the automated combination of the data from the different imaging modalities (i.e. image fusion) will be a topic of major research in the future. As a current and practical example, the image fusion of biplane x-ray arteriography and 3D intravascular ultrasound is discussed.