Model based LV-reconstruction in bi-plane x-ray angiography

Backfrieder, Werner; Carpella, M.; Swoboda, Roland; Steinwender, Clemens; Gabriel, Christian; Leisch, F

doi:10.1117/12.594849

Cited by 3 publications

(2 citation statements)

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“…The algorithm [6] utilizes contour information obtained from segmentation to define the location of X-ray attenuation profiles of the ventricle, see Figure 1. Reconstruction of a ventricular cross-section is based on deformable models [7].…”

Section: Model Reconstructionmentioning

confidence: 99%

From 2D to 4D in quantitative left ventricle wall motion analysis of biplanar X-ray angiograms

Swoboda¹,

Carpella²,

Steinwender

et al. 2005

Computers in Cardiology, 2005

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Accurate assessment of regional myocardial function after infarction is a challenging task in biplanar X-ray cineangiography. An estimate of motion is given by tracking contours of the left ventricle (LV) in projection images.In conventional clinical practice, LV wall motion analysis is done in 2D, based on end-diastolic and end-systolic contours. Our work, by contrast, presents novel methods for analyzing left ventricular motion in 4D, making possible the evaluation of myocardial function in any region of the ventricle rather than at artificial boundary areas in the projection image.4D LV models are reconstructed from a biplanar image sequence. The centerline and radial method, originally developed for analysis in 2D, are extended to 3D for assessment of cardiac motion based on our 4D ventricular model. Color-encoded ventricle models and 2D maps of heart wall dynamics are developed for visualization. Results obtained by using the methods presented herein are in correspondence with clinical findings. IntroductionInterventional X-ray angiography is state of the art in diagnosis and treatment of cardiovascular diseases. To diagnose viability of myocardium after infarction, for instance, X-ray images of the left ventricle are acquired with biplanar cineangiography equipment. A major drawback of the underlying imaging modality is the loss of 3D information, as objects are projected onto a 2D image plane. Consequently, only motion of the outer ventricular shape is visible in the images.In clinical practice, quantitative left ventricle analysis is based on end-diastolic and end-systolic contours. For wall motion analysis (WMA) in 2D, several methods have been developed in the past [1,2,3]. But as no 3D information is available, myocardial function is only assessed at the ventricular boundary area projected to the image. This work, however, illustrates how myocardial activity can be evaluated in 4D based on 3D models of the LV evolving in time. 2.Material and methods DataAngiography data is recorded with a Siemens BICOR system, capturing 8-bit gray level images of size 512x512 pixels at a frame rate of 25fps. A 4D model of the contracting ventricle, reconstructed from a biplanar image sequence, provides the basis for quantitative analysis of LV wall motion. LV model reconstructionAccuracy of X-ray image acquisition is affected by pincushion distortion and spiral distortion [4]. Thus, distortion correction is performed prior to segmentation and reconstruction, based on an approach using control points obtained from a reference image. For semi-automatic segmentation, statistical shape models of the LV are deduced from a set of expert-segmented images [5]. Principle Component Analysis (PCA) of the shape model determines a circumferential region of interest where the contour of the LV is most likely detected.A 3D LV contour model is reconstructed slice-by-slice from biplanar images. The algorithm [6] utilizes contour information obtained from segmentation to define the location of X-ray attenuation profiles of the ventricle...

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Section: Model Reconstructionmentioning

confidence: 99%

From 2D to 4D in quantitative left ventricle wall motion analysis of biplanar X-ray angiograms

Swoboda¹,

Carpella²,

Steinwender

et al. 2005

Computers in Cardiology, 2005

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“…When using a biplane system, the epipolar constraint can be exploited in order to compute the 3-D LV shape from two orthogonal simultaneously acquired projection images (Hartley & Zisserman 2004). In Backfrieder et al (Backfrieder et al 2005), initial super ellipses are deformed until their projection profiles optimally fit to the measured projections. The generated model can be used to perform an LV wall motion analysis (Swoboda et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Interventional heart wall motion analysis with cardiac C-arm CT systems

Müller¹,

Maier²,

Zheng³

et al. 2014

Phys. Med. Biol.

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Today, quantitative analysis of 3-D dynamics of the left ventricle (LV) cannot be performed directly in the catheter lab using a current angiographic C-arm system, which is the workhorse imaging modality for cardiac interventions. Therefore, myocardial wall analysis is completely based on the 2-D angiographic images or pre-interventional 3-D/4-D imaging. In this paper, we present a complete framework to study the ventricular wall motion in 4-D (3-D+t) directly in the catheter lab. From the acquired 2-D projection images, a dynamic 3-D surface model of the LV is generated, which is then used to detect ventricular dyssynchrony. Different quantitative features to evaluate LV dynamics known from other modalities (ultrasound, MR) are transferred to the C-arm CT data. We use the ejection fraction (EF), the systolic dyssynchrony index (SDI), a 3-D fractional shortening (3DFSi) and the phase to maximal contraction (φi,max) to determine an indicator of LV dyssynchrony and to discriminate regionally pathological from normal myocardium. The proposed analysis tool was evaluated on simulated phantom LV data with and without pathological wall dysfunctions. The used LV data is publicly available online at https://conrad.stanford.edu/data/heart. In addition, the presented framework was tested on eight clinical patient data sets. The first clinical results demonstrate promising performance of the proposed analysis tool and encourage the application of the presented framework to a larger study in clinical practice.

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