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PubMed2005

Visibility of normal thoracic anatomic landmarks on storage phosphor digital radiography versus conventional radiography.

BACKGROUND: Chest radiography is still the most frequently performed radiologic imaging study. Digital radiography is gradually replacing the conventional systems. OBJECTIVES: To compare the subjective visibility of normal anatomic landmarks in the chest on storage phosphor-based digital radiographs versus conventional screen-film radiographs. METHODS: Digital phosphor-based and screen-film posteroanterior chest radiographs were obtained during 1 year in 140 asymptomatic patients without any known pulmonary disease (119 men, 21 women; mean age 52.1 years, range 23-86). Both sets of films were independently compared by two experienced radiologists in different sessions. The visibility of each of the following anatomic landmarks was graded from 1 to 3: pulmonary fissures, carina, bronchi to left upper lobe, right upper lobe and left lower lobe, bronchus intermedius, anterior and posterior junctional lines, and vessels behind the heart and diaphragm. Additionally, subjective general quality impression of each radiograph was graded similarly. Statistical analyses were performed using the chi-square test. A P value less than 0.05 was considered significant. RESULTS: Visibility with the digital images was statistically significantly higher for the carina, left lower lobe bronchus, bronchus intermedius, and vessels behind the heart and diaphragm. Subjective general quality impression of digital radiographs was also higher (P < 0.001). No significant visibility differences were found for pulmonary fissures or junctional lines. CONCLUSION: Subjective visibility of anatomic structures behind the heart and diaphragm and at the hilae is significantly improved with phosphor-based digital radiography compared with conventional screen-film radiography. This suggests that pathologic processes such as pulmonary nodules, masses or consolidations projected over those structures may be more easily and reliably depicted on digital than on conventional chest X-rays.

Adult↗
PubMed1993

Advanced multiple beam equalization radiography (AMBER) combined with computed radiography. Preliminary evaluation.

The combined use of AMBER (Advanced Multiple Beam Equalization Radiography) and a digital storage phosphor (SP) radiography system was evaluated for chest radiography in a pilot study with 4 patients. Four image modes with different dose levels were compared: the SP in combination with an AMBER equalized exposure (SP/AMBER) and 3 nonequalized exposures with dose levels corresponding to the respective calculated AMBER lung dose (SP/lung field dose), the calculated AMBER mediastinal dose (SP/mediastinal dose) and the calculated AMBER average dose (SP/average dose). All image modes were matched for Hurter and Driffield characteristics and subjectively rated according to visibility of details. The improved signal-to-noise (S/N) ratio of SP/AMBER resulted in a better visualization of structures in the mediastinum and the basal lung where SP/lung field dose scored lowest. For the central lung no quality differences were seen between techniques. The compressed dynamic range of the SP/AMBER images was more easily displayed on the hard-copy film. The combination of AMBER with SP radiography promises to overcome the dynamic range limitations of digital displays while, at moderate doses, giving better S/N and image quality than standard SP technique.

Adult↗
PubMed1994

A comparison of conventional screen-film radiography and hard copy of computed radiography in full and two-thirds sizes in detection of interstitial lung disease.

This study examined whether hard-copy radiographs produced from computed radiography (CR) images show the subtle interstitial pulmonary disease equally well to conventional screen-film radiographs, because a digital radiography should be chosen for introduction of the digital picture archiving and communication system (PACS) for the new Osaka University Hospital. Eleven radiologists examined 20 abnormal and 20 control chest radiographs presented in each of three groups: conventional screen-film radiographs and two sizes of hard-copy radiographs made from CR images. This study of digital image quality of chest examinations found that some findings on conventional screen-film radiography images are not reproduced by current CR (2,000 x 2,000 x 10 bits in matrix), especially when the experienced radiologists were observed. This finding suggested improvements are needed in CR before CR of chest should fully replace conventional screen-film radiography.

Hospitals, University↗
PubMed2002

Direct digital radiography versus storage phosphor radiography in the detection of wrist fractures.

AIM: To define the value of digital radiography with a clinical flat panel detector system for evaluation of wrist fractures in comparison with state of the art storage phosphor radiography. MATERIAL AND METHODS: Hard copy images of 26 fractured wrist specimens were acquired with the same exposure dose on a state of the art storage phosphor radiography system and a clinical flat panel detector. Image features like cortical bone surface, trabecular bone, soft tissues and fracture delineation were independently analysed by 4 observers using a standardised protocol. Image quality ratings were evaluated with an analysis of variance (ANOVA). RESULTS: Flat panel detector radiographs were rated superior with respect to cortical and trabecular bone representation as well as fracture evaluation, while storage phosphor radiographs produced better soft tissue detail. CONCLUSION: In some of the observed image quality aspects, the performance of caesium iodide/amorphous silicon flat panel detector exceeds state of the art storage phosphor radiography. This makes it well suited for skeletal imaging particularly in trauma as seen in the detection of wrist fractures.

Analysis of Variance↗
PubMedDate not supplied

Heavy-ion radiography: density resolution and specimen radiography.

Heavy-ion radiography is performed by the passage of a beam of nuclei accelerated to energies of several hundred MeV/nucleon through an object. The technique of recording transmitted nuclei in a downstream stack of plastic sheets affords excellent resolution of density by recording the nuclei only at their stopping points. Imaging of a phantom--which stimulated tumors of low density contrast in a body part--by conventional radiography, computed tomographic scanning and the heavy-ion technique indicated superior density resolution for heavy-ion imaging at radiation dose. Superior imaging of tumors in pathologic specimens was demonstrated for heavy-ion imaging compared to conventional radiography. Values of stopping power for various tumors and normal tissues were determined by a computer-aided technique. Heavy-ion radiography shows promise for superior imaging of low contrast tumors at relatively low radiation low levels.

Achilles Tendon↗
PubMed2005

Computed radiography and direct radiography: influence of acquisition dose on the detection of simulated lung lesions.

PURPOSE: We sought to evaluate the performance of dual-readout and single-readout computed radiography compared with direct radiography for detecting subtle lung abnormalities with a standard and a low-dose technique. MATERIALS AND METHODS: Posteroanterior radiographs of an anthropomorphic chest phantom were obtained with a single-readout storage phosphor radiography system (CRS, pixel size 200 microm), a dual-readout storage phosphor radiography system (CRD, pixel size 100 microm), and a direct detector (DR, pixel size 143 microm) at dose levels of 400 and 800 speed. Ten templates were superimposed to project 4 types of lesions over low- and high-attenuation areas, simulating nodules, micronodules, lines, and patchy opacities. Six radiologists evaluated 60 hard-copy images for the presence or absence of lesions. Statistical significance of differences was evaluated using receiver operating characteristic analysis and analysis of variance. RESULTS: For both low- and high-attenuation areas, CRD (Az = 0.85 and 0.66) was superior to CRS (Az = 0.75 and 0.58) for overall performance and all lesion subtypes (P < 0.05). DR (Az = 0.87 and 0.67) performed slightly better than CRD, being significant only for the detection of micronodules. Acquisition dose significantly affected only the detection of lines and micronodules, whereas the detection of nodules and patchy opacities was not significantly different with reduced exposure, regardless of the system used. CONCLUSION: The dual-readout CR system significantly outperformed the single-readout CR and almost equaled the performance of DR. Dose reduction was more critical for small-sized lesions (micronodules, lines) than for nodular or patchy opacifications and affected mainly the lesions in high attenuation areas.

Humans↗
PubMed1987

Breast imaging: dual-energy projection radiography with digital radiography.

Dual-energy projection radiography was applied to breast examinations. To perform the dual-energy subtraction radiography with use of a digital radiography unit, high- and low-energy projections were made at an appropriate time interval under differing x-ray exposure conditions. Dual-energy projection radiography appears to offer clear, detailed images and may be a useful supplement to standard mammography.

Breast Neoplasms↗
PubMed1999

Selenium-based digital radiography versus conventional film-screen radiography of the hands and feet: a subjective comparison.

OBJECTIVE: The purpose of this study was to subjectively compare the visibility of normal anatomy of the hands and feet using selenium-based digital radiography versus conventional film-screen (100-speed) radiography. SUBJECTS AND METHODS: Digital and film-screen images of the hands and feet of 24 patients were obtained without an antiscatter grid using identical X-ray exposure. Each pair of images was evaluated independently by five experienced radiologists for visibility of normal anatomy using a six-point rating scale. Soft tissues, cortical bone, and trabeculae were evaluated. For each observer, "equivalence" was defined as a mean difference in image quality of less than 1 unit on the 0-5 scale used in the study. Paired t tests were also performed to determine whether the average visibility rating of one technique was statistically superior to that of the other at a .05 level of significance for each observer and at each anatomic landmark. RESULTS: In all categories, selenium-based digital images were rated equivalent to film-screen images by the five observers. Using the sum of the nine landmarks, four of the five observers rated the quality of selenium-based digital images superior to that of film-screen images. CONCLUSION: Subjective visibility of normal anatomy of the hands and feet using selenium-based digital radiography was similar to that achieved using conventional film-screen radiography.

Aged↗
PubMed2002

Screening panoramic radiography of new adult patients: diagnostic yield when combined with bitewing radiography and identification of selection criteria.

OBJECTIVES: To measure the radiological diagnostic yield on screening panoramic radiographs taken of new adult patients and to identify selection criteria for panoramic radiography of new adult patients. DESIGN: Survey of 1,817 consecutive panoramic radiographs taken as 'routine' on new patients with statistical analysis of clinical and radiological findings. SETTING: All radiographs were obtained from 41 general dental practitioners (GDPs). The GDPs provided the clinical information about the patient obtained by history and examination. Collection of material occurred in 1998/1999. MATERIALS AND METHODS: Two dental radiologists recorded the radiological findings on each of 1,817 panoramic radiographs by consensus. Those findings that would have been identified from bilateral posterior bitewing radiographs of each patient were then excluded to give modified figures for radiological findings. MAIN OUTCOME MEASURES: Indices of diagnostic yield were devised and calculated for each radiograph from the data on radiological findings. Total diagnostic yield (DY) and modified diagnostic yield (MDY), after exclusion of findings identifiable on bitewing radiographs, were both calculated. Clinical indicators of a high MDY were identified using stepwise multiple regression analysis. RESULTS: MDY was 0 for 17% of the radiographs (all patients) and 23% of the radiographs when the asymptomatic group were considered. The clinical variables for which the significance was high (p < 0.001) were: increasing number of teeth with clinical suspicion of periapical pathology, presence of partially erupted teeth, increasing number of clinically evident carious lesions, partially dentate status and presence of crowns. CONCLUSION: Taking posterior bitewing radiographs of new adult patients would reduce the diagnostic yield identified solely by panoramic radiography. Using clinical factors derived from the history and examination as radiographic selection criteria modestly improves the odds of achieving a high diagnostic yield from panoramic radiography.

Adult↗
PubMed2001

Root fracture detection: a comparison of direct digital radiography with conventional radiography.

OBJECTIVES: To compare the diagnostic potential of direct digital radiography with conventional film for detecting experimental root fractures. METHODS: Two hundred and one extracted single-rooted human teeth were endodontically instrumented and divided into two groups, a control group of 100 teeth and a fractured group of 101 teeth in which root fractures were produced experimentally. Each tooth was imaged using the paralleling technique with a CCD-based digital system and D-speed film. The images were interpreted by an experienced radiologist without prior knowledge of the distribution of the root fractures. The degree of agreement in detecting root fractures with each imaging system compared with the actual condition was expressed as the kappa value. The difference between the radiographic systems was then assessed by chi(2)-test at the 95% significance level. RESULTS: There was substantial agreement between the digital system and the actual condition (kappa=0.71; 95% Confidence Interval: 0.62 to 0.80) and close agreement between the film and the actual condition (kappa=0.63; 95% Confidence Interval: 0.53 to 0.74). However, this difference was not significantly different (P=0.2). CONCLUSIONS: The performance of CCD-based digital radiography in detecting root fractures is similar to film-based radiography.

Chi-Square Distribution↗
PubMed2003

Productivity and cost assessment of computed radiography, digital radiography, and screen-film for outpatient chest examinations.

An objective assessment and comparison of computed radiography (CR) versus digital radiography (DR) and screen-film for performing upright chest examinations on outpatients is presented in terms of workflow, productivity, speed of service, and potential cost justification. Perceived ease of use and workflow of each device is collected via a technologist opinion survey. Productivity is measured as the rate of patient throughput from normalized timing studies. The overall speed of service is calculated from the time of examination ordering as stamped in the radiology information system (RIS), to the time of image availability on the picture archiving and communication system (PACS), to the time of interpretation rendered (from the RIS). A cost comparison is discussed in terms of potential productivity gains and device expenditures. Comparative results of a screen-film (analog) dedicated chest unit versus a CR reader and a DR dedicated chest unit show a higher patient throughput for the digital systems. A mean of 8.2 patients were moved through the analog chest room per hour, versus 9.2 patients per hour using the CR system and 10.7 patients per hour with the DR system. This represents a 12% increase in patient throughput for CR over screen-film; a 30% increase in patient throughput for DR over screen-film, which is statistically significant; and a 16% increase in patient throughput for DR over CR, which is not statistically significant. Measured time to image availability for interpretation is much faster for both CR and DR versus screen-film, with the mean minutes to image availability calculated as 29.2 +/- 14.3 min for screen-film, 6.7 +/- 1.5 min for CR, and 5.7 +/- 2.5 min for DR. This represents an improved time to image availability of 77% for CR over screen-film, 80% for DR over screen-film, and 15% for DR over CR. These results are statistically significant (P <.0001) for both CR over screen-film and DR over screen-film but not statistically significant for DR over CR. A comparison of the digital technology costs illustrates that the high cost of DR may not be justifiable unless a facility has a steady high patient volume to run the device at or near 100% productivity. Both CR and DR can improve workflow and productivity over analog screen-film in a PACS for delivery of projection radiography services in an outpatient environment. Cost justification for DR over CR appears to be tied predominantly to high patient volume and continuous rather than sporadic use patterns.

Ambulatory Care Facilities↗
PubMed1990

Fine-detail panoramic radiography by free-focus radiography. A clinical demonstration of diagnostic radiographs.

Previous comprehensive clinical studies have shown that free-focus radiography (FFR) may be used to improve image detail and diagnostic value in panoramic radiography of the teeth and jaws. This study demonstrated the clinical image quality in fine-detail panoramic FFR surveys relative to conventional surveys made by rotational panoramic or intraoral radiography. Cases of particular diagnostic interest with respect to common dental disease and changes in the jaws were included. The radiographic area of diagnostic interest depicted in FFR surveys generally resembled that of conventional dental radiographic surveys with the use of intraoral films rather then those of conventional rotational panoramic surveys.

Adolescent↗
PubMed1998

Selective cervical spine radiography in blunt trauma: methodology of the National Emergency X-Radiography Utilization Study (NEXUS).

Fear of failure to identify cervical spine injury has led to extremely liberal use of radiography in patients with blunt trauma and remotely possible neck injury. A number of previous retrospective and small prospective studies have tried to address the question of whether any clinical criteria can identify patients, from among this group, at sufficiently low risk that cervical spine radiography is unnecessary. The National Emergency X-Radiography Utilization Study (NEXUS) is a very large, federally supported, multicenter, prospective study designed to define the sensitivity, for detecting significant cervical spine injury, of criteria previously shown to have high negative predictive value. Done at 23 different emergency departments across the United States and projected to enroll more than 20 times as many patients with cervical spine injury than any previous study, NEXUS should be able to answer definitively questions about the validity and reliability of clinical criteria used as a preliminary screen for cervical spine injury.

Cervical Vertebrae↗
PubMed1993

Alveolar consolidation detection: advanced multiple beam equalization radiography versus conventional chest radiography.

Advanced multiple beam equalization radiography (AMBER) and conventional chest radiography were prospectively evaluated in the detection and quantitation of alveolar (air-space) consolidation. Thirty-seven healthy volunteers underwent bronchoalveolar lavage (BAL), the retained lavage fluid serving as a model for alveolar consolidation. After BAL, the subjects underwent AMBER and conventional chest radiography. The lower lung zones on the radiographs were divided into four zones and graded for alveolar consolidation by three observers. There was no significant difference in the area under the receiver operating characteristic curve between the two techniques in the detection of lavage fluid. The grade of opacification was rated significantly higher (P < .05) on conventional radiographs for three of the four lung zones examined, and the correlation between the quantity of retained lavage fluid and grade of opacity was better on conventional radiographs. Detection of lavage fluid was poor with either technique. The exposure compensation of AMBER was evident in this model of air-space disease but did not affect overall observer performance.

Adult↗
PubMed1994

In vitro comparison of D- and E-speed film radiography, RVG, and visualix digital radiography for the detection of enamel approximal and dentinal occlusal caries lesions.

The aims of this study were (1) to compare the accuracy of conventional D- and E-speed film radiography and direct digital radiography using the RadioVisioGraphy and Visualix systems for the detection of enamel approximal caries lesions and (2) to compare the accuracy of D- and E-speed films and the Visualix system for the detection of dentinal occlusal caries lesions. In total, 122 approximal surfaces were examined in vitro by 3 observers and 65 occlusal surfaces by 2 observers. The true caries diagnosis was based on histological assessment of the surfaces after sectioning the teeth. Approximal surfaces were deemed diseased by the presence of a demineralization in enamel, while occlusal surfaces were deemed diseased by the presence of a demineralization into dentine. The diagnostic accuracy for each radiographic method was expressed as a receiver operating characteristic (ROC) curve area. For the approximal surfaces, the areas under the ROC curves ranged from 0.53 (Visualix) to 0.70 (E-speed film). For the occlusal surfaces, the areas ranged from 0.62 (Visualix) to 0.79 (D- and E-speed films). No statistically significant differences between mean ROC curve areas for the radiographic methods were found either for the approximal or for the occlusal surfaces. It was concluded that radiography was of almost no value in the detection of enamel approximal caries lesions, but of some value in the detection of dentinal lesions in occlusal surfaces.

Bicuspid↗
PubMed1994

Conventional chest radiography vs dual-energy computed radiography in the detection and characterization of pulmonary nodules.

OBJECTIVE: We evaluated a single-exposure, phosphor-plate, dual-energy imaging device that produces, in addition to conventional chest radiographs, both tissue- and bone-selective images. Our purpose was to determine whether dual-energy radiography was more accurate than routine chest radiography for detection and characterization of pulmonary nodules. SUBJECTS AND METHODS: Two hundred patients undergoing chest CT were asked to volunteer to have dual-energy and conventional chest radiographs obtained immediately before or after their CT scan. Radiographs from a subset of 50 of these patients with 116 CT-detected nodules and 10 patients with normal findings on CT scans of the chest were presented to the observers for the nodule detection study. Similarly, radiographs from a subset of 29 patients with 20 calcified and 20 uncalcified nodules were presented to five observers to determine nodule calcification. Dual-energy images were produced by filtering the X-ray tube output with a gadolinium sheet while using a multiple phosphor plate receptor. A dual-energy triad of images consisting of a conventional image, a tissue-selective image, and a bone-selective image were produced. The conventional chest radiographs and dual-energy image sets were presented to observers in random order. Data from a free response receiver operating curve and a receiver operating curve were generated for nodule detection and characterization, respectively. RESULTS: By using the dual-energy images, all five observers improved their ability to diagnose pulmonary nodules (p = .0005) and to characterize nodules as calcified (p = .005). CONCLUSION: By eliminating rib shadows with tissue-selective images and enhancing calcified structures with bone-selective images, dual-energy chest radiography improved the ability of all observers, regardless of expertise, to detect and characterize pulmonary nodules.

False Positive Reactions↗
PubMed2000

Digital radiography versus conventional radiography in chest imaging: diagnostic performance of a large-area silicon flat-panel detector in a clinical CT-controlled study.

OBJECTIVE: The objective of this study was to compare the diagnostic performance of a digital large-area silicon flat-panel detector with that of a conventional screen-film system in clinical chest imaging using abnormal findings documented by CT as the reference standard. SUBJECTS AND METHODS: Eighty patients (46 men and 34 women; age range,18-91 years; mean age, 63 years) who underwent CT of the chest were examined with the new digital radiography system, which is based on a 43 x 43 cm silicon flat-panel detector, and with a conventional screen-film system, which is used routinely in clinical practice. Posteroanterior and lateral radiographs were obtained. Four radiologists analyzed the digital and conventional images separately for chest abnormalities and rated the images using a five-level scale of confidence; CT was used as the reference standard. Diagnostic value was assessed using receiver operating characteristic curves for each abnormality. RESULTS: No significant differences were found between the area under the receiver operating characteristic curve of the digital and that of the conventional radiography method for almost all investigated criteria. The only exception was mediastinal abnormalities, for which the digital method provided better results than the conventional method (p < 0.05). CONCLUSION: The diagnostic performance of the new large-area silicon flat-panel detector is equivalent or superior to that of the conventional screen-film system for clinical chest imaging and can replace conventional radiography systems. This new technology offers transmission and storage possibilities inherent to digital radiology that would facilitate daily practice and reduce the initial high costs in the long-term.

Adolescent↗
PubMed1990

[The experimental and clinical evaluation of digital chest radiography using FCR (Fuji Computed Radiography)].

Image quality of digital chest radiography using FCR (Fuji Computed Radiography) was evaluated experimentally and clinically, comparing with the conventional radiography using regular film-screen system (F-S system). 1. In experimental study, Burger's phantom and Hawlet chart were used. The results were as follows: 1) Almost same amount of incident X-ray exposure was necessary for FCR to obtain the same resolution power as F-S system. 2) Contrast enhancement processing did not improve resolution power in FCR. It was improved by the processing of spatial frequency enhancement in the range of lower than 0.5 c/mm, but was decreased by the same processing in the range of higher than 0.5 c/mm. 2. In clinical study, chest radiograms of FCR and F-S system which were taken at the same day were evaluated. The results were as follows. 1) Firstly, the visibility of abnormal shadows which were classified into nine types was evaluated subjectively by two chest-radiologists. As the results, FCR was superior to F-S system in visibility of the lesions overlapping mediastinum and diaphragm, calcifications and bone lesions. FCR was, however, inferior to F-S system in visibility of ground glass shadows, fine reticular shadows and granular shadows. 2) In the second step, the detectability of those interstitial shadows was evaluated using ROC curve analysis. As the results, FCR was statistically inferior to F-S system in detectability of those interstitial shadows.

Evaluation Studies as Topic↗