A multiscale tracking algorithm for the coronary extraction in MSCT angiography

Diagnostic value of ultrasound score, color Doppler ultrasound RI and spiral CT for ovarian tumors

Diagnostic value of ultrasound score, color Doppler ultrasound resistance index (RI) and spiral computed tomography (CT) for ovarian tumors was investigated. In total 224 patients pathologically diagnosed with ovarian tumor after operation in Cangzhou Central Hospital were selected, including 120 patients with benign ovarian tumor and 104 patients with malignant ovarian tumor. Patients with benign and malignant tumors were scored according to the ultrasound scoring criteria. The color Doppler ultrasound examination was performed and the corresponding RI was recorded. At the same time, 64-slice spiral CT was performed, and results were compared with the postoperative pathological diagnosis. Also, the sensitivity, specificity and accuracy of the combined application of the three methods were detected. The RI value of benign ovarian tumor was higher than that of malignant ovarian tumor, displaying statistically significant difference (P<0.05). The sensitivity, specificity and accuracy of the combined application of the three methods were 96.49, 90.91 and 93.75%, respectively. Ultrasound scoring, color Doppler ultrasound RI and 64-slice spiral CT have good diagnostic value for ovarian tumor, and the diagnostic accuracy rate of the combined application is higher. Therefore, different examination methods can be selected in clinic according to the different situations.

Simulation environment of X-ray rotational angiography using 3D+t coronary tree model

The newly introduced cardiac rotational angiography (RA) can provide a large amount of projections from different angles which greatly improve the 3D coronary tree reconstruction. However, the reconstruction methods are difficult to be objectively evaluated due to the complicated topology of coronary tree and non-linear cardiac motion. In this paper, we present a simulation environment of rotational angiography acquisition system to facilitate the improvements and the evaluations of reconstruction algorithms. A 3D+t coronary tree model reconstructed from MSCT sequence is employed to enhance the reality of simulation. A simulation environment of X-ray coronary angiography is developed based on distance-driven projection algorithm. The static angiography is firstly simulated to verify the dynamic model by comparing the displacements of landmarks with the real static angiography of the same patient. Rotational simulation results are then obtained with real system parameters to provide a complete and true-to-life RA sequence representing the morphology of moving coronary tree.

ECG gated tomographic reconstruction for 3-D rotational coronary angiography

A method is proposed for 3-D reconstruction of coronary from a limited number of projections in rotational angiography. A Bayesian maximum a posteriori (MAP) estimation is applied with a Poisson distributed projection to reconstruct the 3D coronary tree at a given instant of the cardiac cycle. Several regularizers are investigated L0-norm, L1 and L2 -norm in order to take into account the sparsity of the data. Evaluations are reported on simulated data obtained from a 3D dynamic sequence acquired on a 64-slice GE LightSpeed CT scan. A performance study is conducted to evaluate the quality of the reconstruction of the structures.

Characterization of 3-D coronary tree motion from MSCT angiography

This paper describes a method for the characterization of coronary artery motion using multislice computed tomography (MSCT) volume sequences. Coronary trees are first extracted by a spatial vessel tracking method in each volume of MSCT sequence. A point-based matching algorithm, with feature landmarks constraint, is then applied to match the 3-D extracted centerlines between two consecutive instants over a complete cardiac cycle. The transformation functions and correspondence matrices are estimated simultaneously, and allow deformable fitting of the vessels over the volume series. Either point-based or branch-based motion features can be derived. Experiments have been conducted in order to evaluate the performance of the method with a matching error analysis.

Liver vessels segmentation using a hybrid geometrical moments/graph cuts method

This paper describes a fast and fully automatic method for liver vessel segmentation on computerized tomography scan preoperative images. The basis of this method is the introduction of a 3-D geometrical moment-based detector of cylindrical shapes within the minimum-cut/maximum-flow energy minimization framework. This method represents an original way to introduce a data term as a constraint into the widely used Boykov's graph cuts algorithm, and hence, to automate the segmentation. The method is evaluated and compared with others on a synthetic dataset. Finally, the relevancy of our method regarding the planning of a necessarily accurate percutaneous high-intensity focused ultrasound surgical operation is demonstrated with some examples.

Standardized evaluation methodology and reference database for evaluating coronary artery centerline extraction algorithms

Efficiently obtaining a reliable coronary artery centerline from computed tomography angiography data is relevant in clinical practice. Whereas numerous methods have been presented for this purpose, up to now no standardized evaluation methodology has been published to reliably evaluate and compare the performance of the existing or newly developed coronary artery centerline extraction algorithms. This paper describes a standardized evaluation methodology and reference database for the quantitative evaluation of coronary artery centerline extraction algorithms. The contribution of this work is fourfold: (1) a method is described to create a consensus centerline with multiple observers, (2) well-defined measures are presented for the evaluation of coronary artery centerline extraction algorithms, (3) a database containing 32 cardiac CTA datasets with corresponding reference standard is described and made available, and (4) 13 coronary artery centerline extraction algorithms, implemented by different research groups, are quantitatively evaluated and compared. The presented evaluation framework is made available to the medical imaging community for benchmarking existing or newly developed coronary centerline extraction algorithms.

Motion compensated tomography reconstruction of coronary arteries in rotational angiography

This paper deals with the 3-D reconstruction of the coronary tree from a rotational X-ray projection sequence. It describes the following three stages: the reconstruction of the 3-D coronary tree at different phases of the cardiac cycle, the motion estimation, and the motion-compensated tomographic reconstruction of the 3-D coronary tree at one given phase using all the available projections. Our method is tested on a series of simulated images computed from the projection of a segmented dynamic volume sequence acquired in multislice computed tomography imaging. Performances are comparable to those obtained by reconstruction of a statical coronary tree using an algebraic reconstruction technique algorithm.

Simulation environment for the evaluation of 3D coronary tree reconstruction algorithms in rotational angiography

We present a preliminary version of a simulation environment to evaluate the 3D reconstruction algorithms of the coronary arteries in rotational angiography. It includes the construction of a 3D dynamic model of the coronary tree from patient data, the modeling of the rotational angiography acquisition system to simulate different acquisition and gating strategies and the calculation of radiographic projections of the 3D model of coronary tree throughout several cardiac cycles.