Learn More
Bone mineral density (BMD) measurements and fracture analysis of the spine bones are restricted to the Vertebral bodies (VBs). In this paper, we propose a novel 3D shape based method to segment VBs in clinical computed tomography (CT) images without any user intervention. The proposed method depends on both image appearance and shape information. 3D shape(More)
The sources of noise in a digital video subtraction angiography system were identified and analyzed. Signal-to-noise ratios of digital radiography systems were measured using the digital image data recorded in the computer. The major sources of noise include quantum noise, TV camera electronic noise, quantization noise from the analog-to-digital converter,(More)
A negative (zero) Agatston coronary calcium score (CCS) by current methods confers a very low risk for hard coronary events during the next years. However, controversy remains on how to use a negative score since some hard events still occur. We report on a new method with improved detection sensitivity for very small calcifications with the potential to(More)
PURPOSE Development and verification of peak signal-to-noise ratio (SNR(P)) equations for determining optimum CT scanning and scoring parameters for a new automated coronary calcium scoring program (N-vivo). Experimental evaluation of the new program for scoring small calcium hydroxyapatite (CaHA) microspheres with small voxel CT images. METHODS(More)
BACKGROUND Test phantoms with simulated micro-calcifications of true calcium hydroxyapatite (CaHA) density were not available to validate advanced calcium scoring methods or plaque density measurements. OBJECTIVES We evaluated a coronary calcium scoring (CCS) test phantom containing very small CaHA microspheres and validated a new scoring method for(More)
The LSF's and MTF's of two high resolution rare-earth screen-film combinations were measured at two beam qualities. The two beam qualities were chosen to provide x-ray spectral distributions either above or below the K-edge of the screen phosphor. The LSF's were found to be photon energy dependent. This energy dependence is attributed to the generation and(More)
A digital radiographic system was used to measure the distribution of scattered x radiation from uniform slabs of Lucite at various thicknesses. Using collimation and air gap techniques, [primary + scatter] images and primary images were digitally acquired, and subtracted to obtain scatter images. The scatter distributions measured using small circular(More)
Bone mineral density (BMD) measurements and fracture analysis of the spine bones are restricted to the Vertebral bodies (VBs). In this paper, we present a novel and fast 3D segmentation framework of VBs in clinical CT images using the graph cuts method. The Matched filter is employed to detect the VB region automatically. In the graph cuts method, a VB(More)
In this paper, we propose a robust level sets method to segment vertebral bodies (VBs) in clinical computed tomography (CT) images. Since the VB and surrounding organs have very close gray level information and there are no strong edges in some CT images, the initialization of level sets method becomes very crucial step. If the object and background regions(More)