by McEvoy, Fintan J.; Svalastoga, Eiliv

The transmission of patient and imaging data between imaging centers and other interested individuals is increasingly achieved by means of compact disc digital media (CD). These CDs typically contain, in addition to the patient images, a DICOM reader and information about the origin of the data. While equipment manufacturers attach disclaimers to these discs and specify the intended use of such media, they are often the only practical means of transmitting data for small medical, dental, or veterinary medical centers. Images transmitted by these means are used for clinical diagnosis. This has lead to a heavy reliance on the integrity of the data. This report describes attempts to alter significant patient and study data on CD media and their outcome. The results show that data files are extremely vulnerable to alteration, and alterations are not detectable without detailed analysis of file structure. No alterations to the DICOM readers were required to achieve this; changes were applied only to the data files. CDs with altered data can be readily prepared, and from the point of view of individuals viewing the images, function identically to the original manufacturer’s CD. Such media should be considered unsafe where there is a potential for financial or other gain to be had from altering the data, and the copy cannot be cross-checked with the original data.

DOI: 10.1007/s10278-007-9068-x
Online Date: 8/21/2007
Print publication date: 2/1/2009
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by Nurkalem, Zekeriya; Sahin, Sinan; Uslu, Nevzat; Emre, Ayse; Alper, Ahmet Taha; Gorgulu, Sevket; Yardi, Fehmi; Eren, Mehmet

Attenuation artifacts are the most common sources of error in myocardial single-photon emission computed tomography (SPECT) imaging. Breast artifacts are the most frequent causes of false positive planar images in female subjects. The purpose of this study was to predict breast adverse attenuation by measuring breast tissue thickness with digital x-ray. Sixty-five consecutive female patients with angina pectoris, who were referred to myocardial perfusion scintigraphy were enrolled in this study. Eighteen patients with normal perfusion imaging and normal coronary angiography composed the first group, whereas the second group consisted of 28 patients with a positive exercise electrocardiogram with anterior ischemia on myocardial perfusion imaging and greater than 50% left anterior descending artery stenosis on angiography. Nineteen patients in the third group had normal exercise electrocardiograms and normal coronary angiographies, but anterior ischemia on perfusion imaging. Digital x-ray records were obtained for measuring breast tissue thickness and Hounsfield density. The rate of breast adverse attenuation was 40% (19/47) in patients with anterior ischemia. The sensitivity and specificity of the prediction of breast adverse attenuation (lateral density less than 550 Hounsfield) were 79% and 11%, respectively. When breast attenuation for a breast thickness greater than 6 cm measured in the left anterior oblique view was predicted, the sensitivity and specificity were 79% and 93%, respectively. In conclusion, breast thickness greater than 6 cm measured from the left anterior oblique view with digital x-ray can predict breast adverse attenuation in female patients, and thereby may decrease the number of unnecessary invasive diagnostic procedures to be performed.

DOI: 10.1007/s10278-007-9048-1
Online Date: 8/17/2007
Print publication date: 12/1/2008
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by Tang, Fuk-hay; Chan, Lawrence W. C.; Lau, Hin-pong; Tsui, Po-yan; Cheung, Chi-wa

An intelligence system was used to generate index for scoliosis. Tests were designed to evaluate the consistency of the automatic computer-generated index and to quantify the correlation between Cobb angle and computer generated scoliosis classification index (SCI). A fully automatic computer-generated index can be used to assess the extent of spinal curvature rather than manual measurement on radiographs. This study aims to evaluate the relation of an automatic computer-generated index in assessing the spinal curvature of scoliosis quantitatively on digital chest images. Sixty chest radiographs were obtained in this study. Cobb angle measurement and the index generated were compared by parametric statistical tests. The SCI method was demonstrated to be reproducible. There was also statically significant positive correlation between Cobb angle and SCI (Pearson’s correlation: r = 0.9229). The Computer-generated index method is valid and reliable in quantifying measurement of spinal curvature of scoliosis as the correlation between Cobb’s angle and SCI in nearly perfect positive for Cobb angle more than 10 degree. It is noted that with widely use of this computer method, this quantitative method proposed is a promising method in improving the reliability of scoliosis assessment and reducing the workload of clinical staff.

DOI: 10.1007/s10278-007-9050-7
Online Date: 8/7/2007
Print publication date: 10/1/2008
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by Kagadis, George C.; Spyridonos, Panagiota; Karnabatidis, Dimitris; Diamantopoulos, Athanassios; Athanasiadis, Emmanouil; Daskalakis, Antonis; Katsanos, Konstantinos; Cavouras, Dionisios; Mihailidis, Dimitris; Siablis, Dimitris; Nikiforidis, George C.

The purpose of our study was to develop a user-independent computerized tool for the automated segmentation and quantitative assessment of in vivo-acquired digital subtraction angiography (DSA) images. Vessel enhancement was accomplished based on the concept of image structural tensor. The developed software was tested on a series of DSA images acquired from one animal and two human angiogenesis models. Its performance was evaluated against manually segmented images. A receiver’s operating characteristic curve was obtained for every image with regard to the different percentages of the image histogram. The area under the mean curve was 0.89 for the experimental angiogenesis model and 0.76 and 0.86 for the two clinical angiogenesis models. The coordinates of the operating point were 8.3% false positive rate and 92.8% true positive rate for the experimental model. Correspondingly for clinical angiogenesis models, the coordinates were 8.6% false positive rate and 89.2% true positive rate and 9.8% false positive rate and 93.8% true positive rate, respectively. A new user-friendly tool for the analysis of vascular networks in DSA images was developed that can be easily used in either experimental or clinical studies. Its main characteristics are robustness and fast and automatic execution.

DOI: 10.1007/s10278-007-9047-2
Online Date: 8/3/2007
Print publication date: 12/1/2008
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