This article reviews the research progress in qualitative evaluation of medical image reconstruction, especially the binary image reconstruction. According to the affected point and evaluation character, the evaluation criteria are classified into four categories. Based on the brief introduction of all kinds of evaluation criteria, the paper makes an analytical comparison, and points out their merit and fault. This study provides a useful basis for selection and design of medical image reconstruction algorithms.
Algorithms ; Evaluation Studies as Topic ; Image Processing, Computer-Assisted ; methods ; standards

To objectively and quantitatively study the effect of JPEG2000 lossy compression of nuclear medicine image, line source images of various noise levels, actual quadrant-bar phantom images and simulated quadrant-bar phantom images of various noise levels were compressed using a JPEG2000 plug-in at 10 : 1 to 50 : 1 with a 10 : 1 step. Modulation transfer function (MTF), full width at half-maximum (FWHM) and the peak to total count ratio (PTCR) of line spread function of the simulated line source images were analyzed quantitatively. Image quality of the quadrant-bar phantom images was visually evaluated according to quality control procedures and the result was used to verify the quantitative analysis. It was observed that PTCR decreased as compression ratio increased and the higher the noise level, the faster PTCR decreased, which was in accordance with the increase of the width of the smallest bars that can be visually resolved in the actual quadrant-bar phantom images and simulated quadrant-bar phantom images. On the other hand, no significant change of MTF and FWHM was observed as compression ratio increased. It was concluded that PTCR may serve as an objectively quantitative metrics of image quality assessment.
Algorithms ; Data Compression ; methods ; standards ; Diagnostic Imaging ; standards ; Humans ; Image Processing, Computer-Assisted ; Nuclear Medicine ; methods

OBJECTIVETo establish the optimal image post-processing parameters for digital chest radiography as preliminary research for introducing digital radiography (DR) to pneumoconiosis diagnosis in China.

METHODSA total of 204 pneumoconiosis patients and 31 dust-exposed workers were enrolled as the subjects in this research. Film-screen radiography (FSR) and DR images were taken for all subjects. DR films were printed after raw images were processed and parameters were altered using DR workstation (GE Healthcare, U.S.A.). Image gradations, lung textures, and the imaging of thoracic vertebra were evaluated by pneumoconiosis experts, and the optimal post-processing parameters were selected. Optical density was measured for both DR films and FSR films.

RESULTSFor the DR machine used in this research, the contrast adjustment (CA) and brightness adjustment (BA) were the main parameters that determine the brightness and gray levels of images. The optimal ranges for CA and BA were 115%∼120% and 160%∼165%, respectively. The quality of DR chest films would be optimized when tissue contrast was adjusted to a maximum of 0.15, edge to a minimum of 1, and both noise reduction and tissue equalization to0.The failure rate of chest DR (0.4%) was significantly lower than that of chest FSR (17%) (P < 0.05).

CONCLUSIONAfter appropriate image post-processing on DR machine purchased from GE Healthcare, the DR chest films can meet all requirements for the quality of chest X-ray films in the Chinese diagnostic criteria for pneumoconiosis.

Humans ; Image Processing, Computer-Assisted ; methods ; Pneumoconiosis ; diagnostic imaging ; Radiographic Image Enhancement ; standards ; X-Ray Film

INTRODUCTIONDigital storage of echocardiographic data offers logistical advantages over videotape archival. However, limited information is available on the accuracy of clinically compressed digitised examinations, an important consideration for patient safety.

MATERIALS AND METHODSTransthoracic echocardiograms of 520 consecutive patients were prospectively acquired digitally and on videotape. Two echocardiologists, in consensus, reported studies in both formats sequentially. Using the videotape as a reference, the significance of any reported differences was graded from both imaging and clinical standpoints, and the reasons for these differences identified.

RESULTSFrom an imaging perspective, differences between digital and videotaped studies were absent or minor in 459 cases (88%), fairly significant in 55 (11%) and very significant in 6 (1%). The main reasons for the observed differences were inadequate acquisition of optimal views (59%), an insufficient number of acquired cardiac cycles (25%) and suboptimal image quality (9%). These differences were considered to be of possible or definite clinical importance in 21 (4%) and 8 (2%) cases, respectively. In multinominal logistic regression models, the only independent predictor of significant difference between digitised and videotaped images was study complexity. Regardless of case complexity, most diagnostic errors arising from digital review were attributable to technical failure rather than observer error.

CONCLUSIONSThe potential for important errors arising from exclusive reporting of clinically compressed digital echocardiograms is small. Digital echocardiography, as practiced in a routine clinical setting, offers a patient-safe alternative to videotape review.

Echocardiography ; methods ; standards ; Humans ; Image Processing, Computer-Assisted ; Prospective Studies ; Safety ; Singapore ; Videotape Recording

Placido disk is widely used in corneal topography. In order to solve the problem that the convex of the corneal can not be precisely located in the Placido corneal topography system, an algorithm of corneal reconstruction based on the Placido disk was introduced. The key of this method is the calculation of radius of corneal convex by using the innermost ring data. Based on image analysis result, we precisely calculated the radius of corneal convex iteratively by connecting the convex and the first ring using a circle, and then calculated the location of all the reflect point and its power. At last we created the pseudo color map of the human corneal. The corneal was simulated by using standard steel sphere, and the calculating errors of the result were all below 0.25D. It showed that the algorithm used in this work could get relatively accurate powers and would have fair stability.
Algorithms ; Cornea ; pathology ; Corneal Topography ; methods ; standards ; Corneal Wavefront Aberration ; Humans ; Image Processing, Computer-Assisted

OBJECTIVETo find a way to view ECG from different manufacturers in electrocardiogram information system.

METHODSDifferent format ECG data were transmitted to ECG center by different ways. Corresponding analysis software was used to make the diagnosis reports in the center. Then we use PDF convert to change all ECG reports into PDF format. The electrocardiogram information system manage these PDF format ECG data for clinic user.

RESULTSThe ECG reports form several major ECG manufacturers were transformed to PDF format successfully. In the electrocardiogram information system it is freely to view the ECG figure.

CONCLUSIONSPDF format ECG report is a practicable way to solve the compatibility problem in electrocardiogram information system.

Electrocardiography ; standards ; Hospital Information Systems ; Image Processing, Computer-Assisted ; methods ; Software

This study briefly introduces the tongue diagnostic equipment of traditional Chinese medicine. It analyzes and discusses the key points of technical evaluation of tongue diagnostic equipment from the aspects of product name, performance parameters, image processing functions, product use methods, clinical evaluation, etc. It analyzes the safety risks and effectiveness indicators of tongue diagnostic equipment, hoping to bring some help to the gradual standardization of tongue diagnostic equipment and the registration of enterprises.
Medicine, Chinese Traditional/methods* ; Tongue ; Image Processing, Computer-Assisted ; Diagnostic Equipment ; Reference Standards

OBJECTIVETo propose a new computer software-based medical image processing technique with high resolution digital scanner for radiotherapy verification.

METHODSUnder the platform of Windows 2000, the software, programmed with Visual C++.NET, was developed according to modular design. All data of the films and the treatment planning system could be processed as images or dose curves for a robust result.

RESULTSMany functions such as data acquisition, automatic analysis and computation and image processing were integrated in the system. Both geometric and dosimetric errors could be calculated at the same time to verify the radiotherapy accuracy.

CONCLUSIONThis system has good accuracy and stability for cost-effective radiotherapy verification.

Film Dosimetry ; instrumentation ; Humans ; Image Processing, Computer-Assisted ; Radiotherapy Dosage ; standards ; Radiotherapy Planning, Computer-Assisted ; methods ; Reproducibility of Results ; Software

OBJECTIVETo study regular patterns of cone artifact resulted from interpolation algorithm of spiral CT.

METHODSBased on the principle of interpolation algorithm and back-projection reconstruction, a mathematical model of the reconstructed image was established to clarify the relation of the scanning parameters and the characteristics of the scanned object with the cone artifact. Experiments were carried out by a set of acrylic phantoms on siemens plus 4 CT scanners.

RESULTSThe artifact in the image was directly proportional to the table increment per gantry rotation of the scanner, and was positively correlated to the tangent of half cone-angle and inversely to the radii in the reconstruction plane of the phantom. The theoretical analysis was validated by experimental results.

CONCLUSIONThe cone artifact is related to the scanning parameters and the characteristics of the scanned object.

Algorithms ; Artifacts ; Computer Simulation ; Image Processing, Computer-Assisted ; methods ; standards ; Models, Theoretical ; Phantoms, Imaging ; Tomography, Spiral Computed ; instrumentation ; methods

This paper presents a medical image acquisition and analysis method-TRM (Topology Resolve-Map) Model-under natural light condition indoors. Firstly, in accordance to medical image color characteristics, a colorful and grayscale color control patch was made for use as supervised color. "Topology Resolve-Map-Restoration" was carried on in LAB color space of the one-dimensional L* space and the two-dimensional a* b* space. Then, L* value was regulated by subsection regulation and a* b* value was regulated by triangulation topological cutting--close in on center of gravity method. After correction of the 198 color blocks in 22 pictures, the results showed that, by comparison with the standard value, the deltaL*, deltaC* and deltaE decreased significantly (P < 0.01) after correction by TRM. After correction, the difference in image's color is reduced, the color saturation is improved and the value is closer to true value. TRM model can significantly reduce the color difference of the medical image under natural light condition; it has a good effect on color correction.
Artificial Intelligence ; Calibration ; Color ; standards ; Humans ; Image Processing, Computer-Assisted ; methods ; Pattern Recognition, Automated ; methods ; Photography ; instrumentation ; methods