In modern medicine, DSA is a powerful technique in visualizations of blood vessels of X-ray images. In DSA, the most important way for motion correction is image registration. In this paper, a new approach to the registration is used. It is based on means of template matching according to a combined invariants-based similarity measure and TPS image warping. Furthermore it has been improved through practice. and tests have proved to remove the motion artifacts effectively and rapidly.
Algorithms ; Angiography, Digital Subtraction ; methods

The compression of medical image series is very important in telemedicine. The motion estimation plays a key role in the video sequence compression. In this paper, an improved square-diamond search (SDS) algorithm is proposed for the motion estimation of medical image series. The improved SDS algorithm reduces the number of the searched points. This improved SDS algorithm is used in wavelet transformation field to estimate the motion of medical image series. A simulation experiment for digital subtraction angiography (DSA) is made. The experiment results show that the algorithm accuracy is higher than that of other algorithms in the motion estimation of medical image series.
Algorithms ; Angiography, Digital Subtraction ; Data Compression ; methods ; Fourier Analysis

A virtual eversion method for human blood vessels is proposed in this paper, based on the virtual eversion methodology along electric field lines, and featured with a reference surface optimization using non-rigid registration. This method has the benefits of easy access with a larger view, and the ability to preserve the vessel's global anatomy and its local spatial relationship with other organs. A CT image dataset of arterial stenosis of lower extremities is tested to implement the virtual eversion experiment, and the results reveal the stenosis of artery clearly, which demonstrates the feasibility of this technique.
Angiography, Digital Subtraction ; methods ; Constriction, Pathologic ; diagnosis ; Humans

Look-up table (LUT) algorithms have been widely used in digital signal processing, but the article on the application of LUT algorithms in digital subtraction angiography was rarely reported. In this article, the effect of different LUT algorithms on digital subtraction angiography images is introduced. The result reveals that different LUT algorithms can bring about different effects of image. Based on analysis and comparison, we deem it possible to acquire improved images of DSA by use of some LUT algorithms with image processing.
Algorithms ; Angiography, Digital Subtraction ; methods ; Humans ; Radiographic Image Enhancement ; methods ; Radiographic Image Interpretation, Computer-Assisted ; methods

In order to remove the artifacts of peripheral digital subtraction angiography (DSA), an affine transformation-based automatic image registration algorithm is introduced here. The whole process is described as follows: First, rectangle feature templates are constructed with their centers of the extracted Harris corners in the mask, and motion vectors of the central feature points are estimated using template matching technology with the similarity measure of maximum histogram energy. And then the optimal parameters of the affine transformation are calculated with the matrix singular value decomposition (SVD) method. Finally, bilinear intensity interpolation is taken to the mask according to the specific affine transformation. More than 30 peripheral DSA registrations are performed with the presented algorithm, and as the result, moving artifacts of the images are removed with sub-pixel precision, and the time consumption is less enough to satisfy the clinical requirements. Experimental results show the efficiency and robustness of the algorithm.
Algorithms ; Angiography, Digital Subtraction ; methods ; Artifacts ; Automation ; methods ; Image Processing, Computer-Assisted ; methods

With 2mm-thick CT scanning during the rapid infusion of contrast material(TICT), cerebral aneurysms arising from the circle of Willis and adjacent vessels can be directly visualized. Twenty-five patients who had cerebral aneurysm confirmed by surgery were examined with TIGT and digital subtraction angiography. The authors examined TIGT prospectively to assess the detection rate of the cerebal aneurysms and to evaluate the clinical usefulness of TIGT. The detection rates of aneurysms by TIGT and digital subtraction angiography were 68% and 84%, respectively. TIGT is a rapid, safe and reliable method in the evaluation of patients with suspected cerebral aneurysm, permitting direct visualization of the aneurysm.
Aneurysm ; Angiography, Digital Subtraction ; Circle of Willis ; Humans ; Intracranial Aneurysm* ; Methods ; Prospective Studies ; Tomography, X-Ray Computed

In digital subtraction angiography (DSA), the contrast of the vessels is greatly improved with the injection of contrast medium. In addition, more clear vessels can be visualized by eliminating the images of non-vessel organs, and those images are called subtraction image or DSA. Therefore, DSA is of wide use for diagnosis of cardiovascular disease. Subtraction of images obtained before and after injection of contrast medium may create motion artifacts due to the aspiration of patients. In this regard, being motivated by the doctors' experience that the displacement of diaphragm can be used as the reference to measure the heart beat, we present a method to eliminate the motion artifacts. In our method, firstly, a set of DSA images are taken before injection of contrast medium, which are called "mask images"; and one image taken after injection of contrast is called "target image". Secondly, a "reference mask image" is assigned, which is one of "mask images"; "and the displacement of diaphragm from "reference mask image" to the other mask images and the target contrast image is measured. Thirdly, based on the measurement results, several candidate mask images in which the displacement is less than a threshold can be selected. At last, the optimization algorithm is applied on the selected images, and the corresponding mask image that has minimum motion artifact is retrieved.
Algorithms ; Angiography, Digital Subtraction ; methods ; Artifacts ; Contrast Media ; Humans ; Image Processing, Computer-Assisted ; Motion

OBJECTIVETo calculate the volume embolization ratio of densely packing experimental aneurysms by three dimensional digital subtraction angiography (3D-DSA).

METHODSSix experimental crotch aneurysms were created microsurgically in the common carotid artery of white rabbits. Two weeks later, each aneurysm's volume was measured with 3D-DSA surface shaded display(SSD) and the correction of lacteprene balloon calibration method. In the same time, the aneurysms were densely packed with electric detachable coils. The volume of coils that were used in each aneurysm was calculated separately. The ratio of coils volume and aneurysm volume was the volume embolization ratio (VER).

RESULTSThe aneurysms volumes measured by 3D DSA SSD ranged from 0.037 to 0.087 ml. The VER ranged from 23.5% to 32.5% (average 27.4%).

CONCLUSIONThe minimum VER of densely packing experimental crotch aneurysms with electronic detachable coils was 23.5%.

According to the patient examination criterion and the demands of all related departments, the DSA digital subtraction workstation has been successfully designed and is introduced in this paper by analyzing the characteristic of video source of DSA which was manufactured by GE Company and has no DICOM standard interface. The workstation includes images-capturing gateway and post-processing software. With the developed workstation, all images from this early DSA equipment are transformed into DICOM format and then are shared in different machines.
Angiography, Digital Subtraction ; instrumentation ; methods ; Image Processing, Computer-Assisted ; Software Design ; User-Computer Interface

Angiography, Digital Subtraction ; Embolization, Therapeutic ; Humans ; Retroperitoneal Neoplasms ; diagnosis ; surgery ; therapy ; Stents ; Vascular Surgical Procedures ; methods