Duplicate Images Research Articles

An Integrated Approach to a Teaching File Linked to PACS

To meet the educational needs of a medical imaging department with a strong teaching commitment, a teaching file that uses digital data supplied by the institutional picture archiving and communications system (PACS) was required. This teaching file had to be easily used by the end users, have a simple submission process, be able to support multiple users, be searchable on all data fields, and implementing the teaching file must not incur any additional software or hardware costs. The teaching file developed to address this problem takes advantage of the database structure and capabilities of several components included in the commercial PACS installed at the hospital. MS Access is used to seamlessly integrate with the digital imaging and communication in medicine (DICOM) database of a normal work station that is part of the PACS. This integration allows relevant patient and study demographics to be copied from images of interest and then to be stored in a separate database as the back-end of the digital teaching file. When images for a particular teaching file case need to be reviewed, they are automatically retrieved and displayed from the main PACS database using an open application programming interface (API) connection defined on the PACS web server. Utilizing this open API connection means the teaching file contains only the relevant demographic information of each teaching file case; no image data is stored locally. The open API connection allows access to imaging data usually not encountered in a teaching file, allowing more comprehensive imaging case files to be developed by the radiologist. Other advantages of this teaching file design are that it does not duplicate image data, it is small allowing simple ongoing backup, and it can be opened with multiple users accessing the database without compromising data access or integrity.

The influence of lower face vertical proportion on facial attractiveness

This study investigated the influence of changing lower face vertical proportion on the attractiveness ratings scored by lay people.Ninety-two social science students rated the attractiveness of a series of silhouettes with normal, reduced or increased lower face proportions. The random sequences of 10 images included an image with the Eastman normal lower face height relative to total face height [lower anterior face height/total anterior face height (LAFH/TAFH) of 55 per cent], and images with LAFH/TAFH increased or decreased by up to four standard deviations (SD) from the Eastman norm. All the images had a skeletal Class I antero-posterior (AP) relationship. A duplicate image in each sequence assessed repeatability. The participants scored each image using a 10 point numerical scale and also indicated whether they would seek treatment if the image was their own profile. The profile image with normal vertical facial proportions was rated by the lay people as the most attractive. Attractiveness scores reduced as the vertical facial proportions diverged from the normal value. Images with a reduced lower face proportion were rated as significantly more attractive than the corresponding images with an increased lower face proportion. Images with a reduced lower face proportion were also significantly less likely to be judged as needing treatment than the corresponding images with an increased lower face proportion.

The influence of mandibular prominence on facial attractiveness

This study examined the attractiveness of facial profiles. One hundred and two social science students (28 males and 74 females) rated the attractiveness of a series of silhouettes with normal, Class II or Class III profiles. A random sequence of 10 images included an image with the Eastman normal SNB value of 78 degrees, and images with SNB values of 2.5, 5, 7.5 and 10 degrees above and below normal. A duplicate image in each sequence was used to assess reproducibility. The participants scored the attractiveness of each image and also indicated whether they would seek treatment if each image was their own profile. The profile with the normal SNB angle of 78 degrees was rated as the most attractive. Attractiveness scores reduced as the mandibular profile diverged from the normal SNB value. The +5 degree profile (SNB = 83 degrees) was rated as significantly more attractive than the -5 degree profile (SNB = 73 degrees; P = 0.004). No other significant differences between the scores for Class II and Class III profile pairs of equal severity were found. At 10 degrees below the normal SNB (Class II), 74 per cent of the sample would elect to have treatment, while 78 per cent would elect to have treatment at 10 degrees above the normal SNB (Class III).

Reliability of a quantification imaging system using magnetic resonance images to measure cartilage thickness and volume in human normal and osteoarthritic knees

Objective: The aim of this study was to evaluate the reliability of a software tool that assesses knee cartilage volumes using magnetic resonance (MR) images. The objectives were to assess measurement reliability by: (1) determining the differences between readings of the same image made by the same reader 2 weeks apart (test–retest reliability), (2) determining the differences between the readings of the same image made by different readers (between-reader agreement), and (3) determining the differences between the cartilage volume readings obtained from two MR images of the same knee image acquired a few hours apart (patient positioning reliability).Methods: Forty-eight MR examinations of the knee from normal subjects, patients with different stages of symptomatic knee osteoarthritis (OA), and a subset of duplicate images were independently and blindly quantified by three readers using the imaging system. The following cartilage areas were analyzed to compute volumes: global cartilage, medial and lateral compartments, and medial and lateral femoral condyles.Results: Between-reader agreement of measurements was excellent, as shown by intra-class correlation (ICC) coefficients ranging from 0.958 to 0.997 for global cartilage (P<0.0001), 0.974 to 0.998 for the compartments (P<0.0001), and 0.943 to 0.999 for the condyles(P<0.0001). Test–retest reliability of within-reader data was also excellent, with Pearson correlation coefficients ranging from 0.978 to 0.999 (P<0.0001). Patient positioning reliability was also excellent, with Pearson correlation coefficients ranging from 0.978 to 0.999 (P<0.0001).Conclusions: The results of this study establish the reliability of this MR imaging system. Test–retest reliability, between-reader agreement, and patient positioning reliability were all extremely high. This study represents a first step in the overall validation of an imaging system designed to follow progression of human knee OA.

Experimental investigation of deformation mechanisms during low drawing of polymeric fibres

Different types of polymeric fibres were studied optically when drawn uniaxially with low draw ratios. A two-beam Pluta polarizing interference microscope was used to investigate optically the deformation types associated with fibre drawing. The fibre was stretched with low draw ratios in steps, and the interference patterns were automatically digitized and stored in a computer data storage media. The data shows that at least three different mechanisms occur when the fibre stretched with draw ratios ranging from 1 to 2. Two-beam duplicated interference images are illustrated.

Detecting duplicates among symbolically compressed images in a large document database

The detection of duplicate images is a useful means of indexing a large database of documents. An algorithm for duplicate document detection is proposed in this paper that operates directly on images that have been symbolically compressed using techniques related to the ongoing JBIG2 standardization effort. This paper describes a hidden Markov model (HMM) method that recognizes the text in an image by deciphering data from the compressed representation. Experimental results show that it can recover better than 90% of the text in compressed document images and that this is sufficient to identify duplicates in a large database.

Effects of a digital filter on detectability of a phantom lesion in a scintigram of the equine tarsus.

The aim of this study was to examine the effects of a digital filter on the detectability of a phantom lesion in a scintigram of the equine tarsus. Lateral images containing 50, 100, 150, 500, or 1000 kcounts were acquired. A created phantom lesion of 0 (normal), 10, 15, 20, or 30% increased intensity relative to local background was placed in the centrodistal tarsal joint area in the images of different count levels. Duplicate images were filtered with a Metz filter. The complete set of filtered and unfiltered images totaling 180 images was projected as slides to a group of 9 observers. The sensitivity in 50 and 100 kcount images was improved by applying the filter. Digital filtering increased the false positive fraction at all count levels but this effect was most pronounced in 500 and 1000 kcount images. Based on receiver operating characteristic analysis, filtering of a 50 kcount image improved image quality to that of a 150 kcount image.

三色照明光を用いたＰＴＶ法による三次元流速測定技術の開発

We developed a technique for measuring instantaneous, three-dimensional velocity components in liquid flows by using a digital image processing system, and here we describe a particle tracking velocimery technique improving the tracking of the initial and terminal positions of tracer particles. By using color cameras and a RGB flashlight source three images of the tracer particles are obtained: one at their initial positions; their ter-minal positions, and along their pathline. The images of the initial and the terminal posi-tions are paired by using the pathline image, and the velocity vectors are calculated. We studied image processing algorithms for obtaining three-dimensional-flow vectors from the images produced by the two cameras and for distinguishing duplicate images of the tracer particles. We confirmed this technique is useful for three-dimensional flow observa-tion.

Reproduction of radiologic images on plain paper.

Skyrocketing health care costs and pressures from managed care have combined to promote cost-cutting strategies in radiology and radiation oncology departments. A study was conducted to evaluate the use of a high-resolution laser printer for printing plain-paper images as substitutes for both original and duplicate radiologic film images. A variety of radiologic images were used to evaluate the image reproduction capabilities of the printer in terms of linearity, detail, and contrast. In many cases, printed images had a quality comparable to that of the original images. Six computed tomographic (CT) scans and six radiation therapy simulator radiographs were compared with printed reproductions by each of seven board-certified radiation oncologists, who rated the reproductions as acceptable for documentation, acceptable for diagnostic purposes (CT scans only), or unacceptable. Ninety-five percent of printed CT images and 90% of printed simulation images were rated acceptable for documentation. The quality of printed images of radiation therapy port films was not quantitatively measured but was improved by adjusting image contrast and brightness and using various image enhancement techniques. The use of printed images is less expensive than that of processed film and eliminates the environmental, time, storage, and delivery problems associated with film. Technologic advances in imaging, networking, and printing have made possible the inexpensive duplication of medical images.

Magnetic resonance imaging compared to echocardiography to assess left ventricular mass in the hypertensive patient

Echocardiography (ECHO) is useful to document changes in left ventricular mass (LVM) in groups of patients, but may be too variable for use in the individual patient. Magnetic resonance imaging (MRI) may be a more precise and reliable method to quantify the mass of the left ventricule. This study reports the accuracy, precision, and reliability of LVM estimates by MRI as compared to data obtained by ECHO in hypertensive patients. Accuracy referred to the comparison of LVM by MRI to anatomical LVM determined by autopsy. Precision was examined using 34 duplicate MRI images and by blindly reading 24 duplicate M-mode strips. Reliability was assessed by MRI in four subjects over 2 months, and by ECHO in 22 hypertensive patients over 2 weeks. Agreement between MRI and ECHO estimates of LVM was determined in the same 17 hypertensive patients using linear regression. MRI LVM estimates were within 17.5 g (95% CI) of the true LVM. The linear agreement between MRI and ECHO estimates of LVM could be described by the equation MRI = 0.61 x ECHO + 49.57 (r = 0.63, P < .01). The precision of LVM by MRI (11 g) was over twice that observed with ECHO (26 g). The reliability of MRI LVM estimates was more consistent (+/- 8 g) than that for ECHO (+/- 49 g). MRI appears to be a more precise and reliable method for measuring LVM, and would be more suitable than ECHO for the clinical evaluation of the individual patient.

System and method for monitoring torsional vibrations and operating parameters of rotating shafts

An optical system for monitor vibration, particularly applicable to power shafts in rotating power systems such as those found in trucks, naval vessels, turbogenerators, hydroelectric and nuclear generators, and helicopters, has an optical unit including IRLED radiation sources aimed at grid lines applied around the circumference of the shaft. The reflection of the radiation is imaged through lenses and a matching Ronchi grid onto a photodiode which produces a periodic wave signal from which indications of rotational irregularities can be derived. In one embodiment, duplicate radiation sources and imaging apparatus are arranged in diametric opposition across the shaft to permit compensation for pitch and plunge shaft vibration. In another preferred embodiment, a second, duplicate optical unit is located at a distance along the shaft from the first unit. The output signals of the two units are passed through a comparator and a EX-NOR gate, then low-pass filtered to produce a signal indicative of torsional deflection. Quadrature techniques can be used to provide shaft directional information. Also disclosed are a method and apparatus for precisely applying finely spaced grid lines to an existing shaft on site. A photosensitive material is applied to the shaft, and a strobe light synchronized to the rotation of the shaft exposes the photosensitive material as the shaft is rotated to create finely spaced grid lines on the material.

Multiple imaging and multiple Fourier transformation using planar microlens arrays

A new type of multiple imaging and multiple Fourier transformation system under coherent illumination using microlens arrays has been developed. The optical system is based on geometrical optics instead of convolution or diffraction. As a result, it has the advantage of design flexibility especially in alignment of the duplicate images. The experimental results of the system, which are implemented using planar microlens arrays fabricated by an ion exchange technique, are also discussed.

Preliminary Evaluation of a Scheme for Grading the Gross Morphology of the Human Intervertebral Disc

A five-category grading scheme for assessing the gross morphology of midsagittal sections of the human lumbar intervetebral disc was developed. The ability of three observers to categorize a series of 68 discs with a wide spectrum of morphologies established the comprehensiveness of the classification. Three independent observers tested the reproducibility of the procedure by assignment of grades blindly to duplicate images of 68 discs taken from 15 spines. The intraobserver agreement ranged from 87 to 91%. The interobserver agreement was 61, 64, and 88% for the three pairs, the two low values being attributable to the bias of one observer. The agreement between the assigned and average grades was 85, 92, 68, 90, and 76% for Grades I through V, respectively. Except for Grade III, the disagreements were attributable mainly to the bias of one observer. Both the increase in the grade with age and the finding that all the discs within 14 of 15 spines had a narrow range of grades demonstrated the biologic credibility of the scheme.

Use of a “sandwich” technique to control image geometry in clinical studies comparing intraoral xeroradiographs and E-speed films

A method of superimposing a film on a xeroradiographic (XR) cassette for simultaneous intraoral exposure is evaluated for use as an imaging technique in clinical studies comparing Ektaspeed film and XR images. Sandwich images were indistinguishable from those produced by conventional technique. Pilot studies were conducted with 104 patients who had symptomatic dental problems. No significant differences were found in diagnostic usefulness or image quality between XR and film radiographs when sign test analysis was used. The sandwich technique yielded film and XR images with duplicate image geometry while reducing patient exposures to one half of that used in conventional image comparison protocols.

Replica images of silver-stained gels using direct duplicating film

A procedure for preparing duplicate images of polyacrylamide gels containing silver-stained proteins using X-ray direct duplicating film is described. Resulting images are shown to be qualitatively and quantitatively faithful representations of the original gel.

Duplication of dental xeroradiographs

This study investigates the duplication of dental xeroradiographs using duplicating (copy) film, Polaroid photography, and Xerox photocopying. Quantitative studies of the image quality of duplicated images demonstrate similar image degradation with duplication film and Polaroid photography and gross degradation with a Xerox photocopier. Subjective diagnostic assessments by general dentists and dental specialists indicated that copies made with the use of duplication film or Polaroid photography were adequate for the reproduction of dental xeroradiographs, whereas Xerox paper copying was unacceptably poor. This study was supported in part by funds from Biomedical Research Support Grant No. 4-529075-24187-3, National Institutes of Health, United States Public Health Service, Bethesda, Md.

Duplication of Color Images with Narrow-Band Filters

Outlined are some of the problems of the users of direct-positive subtractive color films, such as Ansco Color and Kodachrome, in producing acceptable duplicate images which in some cases may be third-generation reproductions. An experimental project will be described in which it was found that it is possible to produce duplicate images which may be directly compared with the camera originals by exposing the duplicating film with filters transmitting three relatively narrow spectral bands. While no attempt has been made in this paper to deal in any detail with the theoretical aspects of color reproduction, a number of factors which are of great concern to the users of color materials have been noted — particularly the establishment of visual acceptance limits for color images, and the influence of processing upon the shape and relationship of the three-color density curves representing an image of a neutral wedge.