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PubMed1991

Detection of bullous lung disease: conventional radiography vs digital storage phosphor radiography.

The detection of fine linear contours and altered aeration are requirements for the radiologic diagnosis of bullous lung disease and are severe measures of the spatial and contrast resolution of chest imaging systems. We compared plain film radiography with five postprocessing algorithms of storage phosphor digital radiography (2144 x 1744 x 10 bit matrix with 0.2-mm pixel size) in the detection of CT-proved bullous lung disease (35 patients and 25 normal control subjects). Receiver-operating-characteristic analysis of 2160 observations by six interpreters was done to evaluate the observers' performance. By analysis of variance (p less than .05), we found that the default digital algorithm and the three edge-enhancing algorithms of high and medium frequencies performed less well than plain films did, but the differences fell short of statistical significance. Gray-scale reversal was the only digital algorithm that performed significantly less well than plain films did. We conclude that any differences between digital algorithms and plain films in the detection of bullous lung disease were too small to be detected in this study. Any difference between the two methods in providing clinically important, diagnostic information is likely to be insignificant.

Algorithms↗
PubMed1991

Photostimulable phosphor digital radiography of the extremities: diagnostic accuracy compared with conventional radiography.

A direct comparison was made between digital and conventional radiographs to assess the relative accuracy of a photostimulable phosphor digital imaging system in detecting and localizing minor trauma in the extremities. Matched sets of images were obtained on 103 patients who came to the emergency department for radiographs of the hand, wrist, foot, or ankle. One set was obtained with a conventional screen/film system. The other set was obtained with photostimulable phosphor digital cassettes. The two sets of images of each patient were independently interpreted by three radiologists in a blinded fashion. The findings of each of these three readers were compared with the consensus opinion of two different radiologists. Receiver-operating-characteristic (ROC) curves were plotted for each of the three readers, areas under the curves were calculated, and true-positive fractions were determined at false-positive fractions of 0.1. Although no significant differences in the areas under the ROC curves for the two imaging systems were detected, conventional radiography showed a slight advantage. However, when true-positive fractions for fracture detection were compared at false-positive fractions of 0.1 a statistically significant difference was shown, with conventional screen/film radiography being more sensitive. This study raises questions about the use of currently available photostimulable phosphor systems for imaging trauma of the extremities and suggests that those systems should not be used exclusively.

Adult↗
PubMed1990

[Evaluation of FCR (Fuji Computed Radiography) images applied to standard radiography for the diagnosis of chest diseases].

FCR (Fuji Computed Radiography) was added to plain chest radiography in order to evaluate its image characteristics and to determine the best image characteristics and to determine the best image processing program by comparing the visibility of shadows on conventional X-rays and on six FCR hard copy images processed by six mutually different image processing program. FCR showed excellent ability to visualize abnormal lung shadows as well as normal chest structures when processed by a moderate spatial frequency enhancement (spatial frequency 0.11 cycle/mm, level of enhancement). FCR also proved superior to the conventional film-screen system in the visualization of hilar and mediastinal structure as well as lung shadows. The effects of the image processing program on the visibility of shadow, granular and linear shadows were clearly demonstrated when a more intense spatial frequency enhancement (spatial frequency 0.18 cycle/mm, level of enhancement) was performed. The same results were obtained in terms of reticular and linear shadows and calcified lesions. On the contrary, low density shadows with poorly defined margins the lung field and infiltrates from mycoplasma pneumonia were well depicted by a program with a slightly steeper gradation (gamma; 1.0) and minimal frequency enhancement. Accordingly, FCR was found to be useful for the screening of abnormal chest X-ray shadows whereas it was also likely to demonstrate the best image when processed by the most appropriate image processing programs, depending on the characteristics of the shadows.

Adult↗
PubMed1999

Direct digital radiography versus conventional radiography for estimation of canal length in curved canals.

A recent development in direct digital radiography (DDR) has made it possible to make additive multiple point (click) measurements of onscreen images. Canal length was examined using four estimation methods: measurement of a conventional D-speed film radiograph, and onscreen DDR allowing two clicks, six clicks, and an unlimited number of clicks of the measuring device. Thirty extracted human teeth with root curvatures ranging from 7 degrees to 47 degrees (Schneider method) were examined. Actual canal length was measured using a millimeter rule and x 2 magnification. Teeth were mounted and prepared for conventional and DDR imaging. Estimated canal length was determined by three board-certified endodontists using each of the four techniques. A two-way analysis of variance indicated that all radiographic techniques resulted in canal lengths that were significantly different from the true canal length, and there was no significant difference between experimental groups, regardless of the canal curvature.

Dental Pulp Cavity↗
PubMed1996

Diagnostic accuracy of direct digital dental radiography for the detection of periapical bone lesions: overall comparison between conventional and direct digital radiography.

OBJECTIVES: The diagnostic accuracy of direct digital radiography for the detection of small, experimentally made, periapical lesions was compared with that of E speed film. The high- and low-contrast resolutions of the imaging systems were also compared. STUDY DESIGN: The high-contrast resolution was evaluated with a line pair plate. The low-contrast resolution was determined with a contrast-detail plexiglass phantom. To evaluate the diagnostic accuracy, the periapical region of dry human mandibles was examined. Receiver operating characteristic based on the readings of seven observers were generated. RESULTS: The high-contrast resolution of the digital system was inferior, but the low-contrast resolution was comparable to that of E-speed film. For diagnostic accuracy no significant difference was seen between the areas under the receiver operating characteristic curves. CONCLUSIONS: The quality of the direct digital images is comparable to that of E-speed film for the detection of periapical bone lesions.

Alveolar Bone Loss↗
PubMed1999

Assessment of image quality in dental radiography, part 2: optimum exposure conditions for detection of small mass changes in 6 intraoral radiography systems.

OBJECTIVE: The purpose of this study was to compare 2 film systems and several digital intraoral systems with regard to visual image quality through use of a test phantom developed for this purpose. STUDY DESIGN: The detectors used for digital imaging were as follows: Computed Dental Radiography (CDR), Digora, Dixel, and Sens-A-Ray without scintillator layer. Two types of digital images were prepared for the observer performance test: one with original gray scales and another with contrast enhancement. Images with and without enhancement from the 4 systems were displayed to 7 observers. The change in the average number of perceptible holes was plotted against exposure, and modified perceptibility curves were created and compared with curves for the film systems. The exposure level at which the maximum number of holes was perceived was defined to be optimum. The optimum exposure levels were determined for each digital system and compared with that of the film systems. At the optimum exposure, the average maximum numbers of perceptible holes in each digital system with and without contrast enhancement were compared with the maximum numbers for the film systems. The minimum exposure levels were determined to be those at which the number of perceptible holes exceeded the number for film, and the possibility of exposure reduction was evaluated. RESULTS: All digital systems except the Digora system showed lower optimum exposures than E-speed film. In all digital images without enhancement, however, the maximum number of perceptible holes was significantly lower than that for the film systems at that exposure. With contrast enhancement, all digital systems except the Sens-A-Ray system showed visibility superior to that of the film systems. With the CDR, Digora, and Dixel systems, exposures could be further reduced by a considerable amount, with greater retention of information than was associated with film. CONCLUSIONS: Our results strongly suggest that digital systems, if properly used, can exceed film systems in the detection of small mass changes.

Contrast Media↗
PubMed1999

Lossy compression should not be used in certain imaging applications such as chest radiography. For the proposition.

Computational techniques are frequently used to compress image data so that transmission and storage requirements are reduced. If the computational techniques result in no loss in image resolution, the technique is referred to as lossless compression. Greater compression of data may yield some loss in spatial or temporal resolution, and is referred to as lossy compression. In some radiologic examinations [e.g., gastrointestinal (GI) studies], some resolution loss may be tolerable, whereas in others (chest examinations and mammography) it conceivably could result in missed pathology. Without lossy compression, however, data requirements can be overwhelming for transmission, storage and retrieval of images such as chest films. The unanswered question, addressed in this Point/Counterpoint issue, is whether some degree of lossy compression can be tolerated in chest radiography.

Humans↗
PubMed2003

Interpretation of normal anatomic structures on chest radiography: comparison of Fuji computed radiography (FCR) 5501D with FCR 5000 and screen-film system.

The purpose of this study was to investigate the usefulness of Fuji Computed Radiography (FCR) 5501D by comparing it with FCR 5000 and a screen-film system (S/F). Posteroanterior chest radiographs of ten patients with no abnormality on chest CT scans were obtained with FCR 5501D, FCR 5000, and S/F. Six observers (three radiologists and three radio-technologists) evaluated the visibility of nine normal anatomic structures (including lungs, soft tissue, and bones) and overall visibility on each image. Observers scored using a five-point scale on each structure. FCR 5000 showed a significantly higher score in soft tissue and bone structures, and overall visibility compared with S/F, but, there was no significant difference between them in the visibility of all four normal lung structures. Compared with S/F, the score for FCR 5501D was higher in eight of the nine normal structures, including three of the four lung structures (unobscured lung, retrocardiac lung, and subdiaphragmatic lung), and overall visibility. Compared with FCR 5000, the score for FCR 5501D was higher in three normal structures, including two of the four lung structures (unobscured lung and subdiaphragmatic lung), and overall visibility. FCR 5501D was the best among the three techniques to visualize normal anatomic structures, particularly the obscured and unobscured lung.

Adult↗
PubMed1986

Radiographic microstructures of early esophageal carcinoma: correlation of specimen radiography with pathologic findings and clinical radiography.

To clarify the exact radiologic features of mucosal carcinoma of the esophagus with a favorable prognosis, contact radiography was performed on 8 surgical specimens diagnosed preoperatively as showing early or superficial carcinoma. Mucosal carcinoma appeared as a well-defined smooth or nodular protrusion or as a feathered flat mucosa with tiny nodulations and barium poolings. Submucosal carcinoma showed a mound-like defect. The size of tumor was not a good index for estimating the depth of invasion. Protruded lesions were easily demonstrated on clinical radiographs and their profile was useful in determining the depth of invasion. Flat lesions were not easy to recognize; attention must therefore be paid not only to mucosal patterns but also to the contour of the esophageal wall.

Aged↗
PubMed2004

[Marburg shoulder radiography splint (MSR splint) for standardized and high quality plain film radiography in fractures of the proximal humerus].

To ensure safe, quick, pain-relieving, standardized, and reproducible high quality plain film radiography in fractures of the proximal humerus, the MSR splint was introduced into clinical practice. With the rectangular and completely radiolucent splint the shoulder radiographs are obtained in supine position by a sole radiographer. Two radiographs are taken in projection at 90 degrees to one another: the true anteroposterior and axillary views, the most important views for fracture visualization and assessment. The smooth flat bottom part of the splint glides easily across the X-ray table below the injured shoulder. The arm lying on the chest is carefully rotated externally up to the neutral position and placed in the splint, then fixed with Velcro fastening with the forearm supinated. The splint is adjusted to the patient for the anteroposterior view which is taken with the central ray directed at the coracoid process and perpendicularly on the film cassette. For the axillary view the MSR splint holding the upper extremity is carefully swiveled into a 80-90 degrees abduction position. Even in cases of comminuted fractures this maneuver is not painful for the patients. The X-ray tube is put into a horizontal position with the central ray pointing to the humeral head in an angle about 25 degrees to the long body axis. The cassette is placed upright in touch with the shoulder girdle. In our institution the MSR splint is not only routinely used for diagnosing fractures of the proximal humerus but also for radiological follow-up controls.

Equipment Design↗
PubMed1992

Chest radiography or computed tomography in the assessment of lung cancer prior to radiography.

A series of 93 patients with lung cancer were considered for intensive radiotherapy, and investigated by chest radiography and computed tomographic (CT) scan. Spread of tumour was detected radiologically to lymph nodes, pleura or chest wall on 98 occasions. Of these, 16 were shown by both investigations, but in 82 the spread was revealed only by CT examination. Clear visualization of the tumour prior to radiotherapy is important to select those patients who would benefit from radical radiotherapy, to allow accurate treatment planning, and to allow, in subsequent follow-up, monitoring of the response to radiotherapy. In this study tumour was clearly visualized in 59 patients treated, but in 31 (53%) of these only by the use of computed tomography.

Aged↗
PubMed1996

Intraoral storage phosphor radiography for approximal caries detection and effect of image magnification: comparison with conventional radiography.

OBJECTIVES: The aim of this study was first to test the newly developed storage phosphor (SP) system Digora for diagnostic accuracy of approximal caries detection with special emphasis on image magnification compared with conventional radiography, and second, to test whether the image surroundings could have an influence on observer performance. DESIGN: SP plates and Ektaspeed films were exposed simultaneously to 50 extracted premolars/molars, and the SP image files were transported to a different platform for processing. Ten observers rated 95 approximal surfaces for caries with four imaging modalities: (1) SP images at dental film size viewed with black surroundings, (2) magnified (x4) images viewed in the same manner, (3) magnified (x4) images viewed with text and graphics framing, and (4) films viewed on a light box. The observations were validated with microscopy. Diagnostic accuracy was calculated as the area beneath the receiver operating characteristic curve (AZ). RESULTS: No significant differences were found between SP images and films. Magnified SP images with text and graphics demonstrated significantly higher AZ values than nonmagnified images both for enamel and dentin, and magnified images with black surroundings demonstrated similar results for dentin. CONCLUSIONS: In this in vitro material the observer performance for approximal caries detection with SP images was comparable to that with Ektaspeed films. The magnified SP images generally showed a significantly higher diagnostic accuracy than the nonmagnified SP images.

Adult↗
PubMed2002

Segmental lumbar spine instability at flexion-extension radiography can be predicted by conventional radiography.

AIM: To identify plain radiographic findings that predict segmental lumbar spine instability as shown by functional flexion-extension radiography. MATERIALS AND METHODS: Plain radiographs and flexion-extension radiographs of 215 patients with clinically suspected lumbar spine instability were analysed. Instability was classified into anterior or posterior sliding instability. The registered plain radiographic findings were traction spur, spondylarthrosis, arthrosis of facet joints, disc degeneration, retrolisthesis, degenerative spondylolisthesis, spondylolytic spondylolisthesis and vacuum phenomena. Factors reaching statistical significance in univariate analyses (P < 0.05) were included in stepwise multiple logistic regression analysis. RESULTS: Degenerative spondylolisthesis (P = 0.004 at L3-4 level and P = 0.017 at L4-5 level in univariate analysis and odds ratio 16.92 at L4-5 level in multiple logistic regression analyses) and spondylolytic spondylolisthesis (P = 0.003 at L5-S1 level in univariate analyses) were the strongest independent determinants of anterior sliding instability. Retrolisthesis (odds ratio 10.97), traction spur (odds ratio 4.45) and spondylarthrosis (odds ratio 3.20) at L3-4 level were statistically significant determinants of posterior sliding instability in multivariate analysis. CONCLUSION: Sliding instability is strongly associated with various plain radiographic findings. In mechanical back pain, functional flexion-extension radiographs should be limited to situations when symptoms are not explained by findings of plain radiographs and/or when they are likely to alter therapy.

Adolescent↗
PubMed1996

[Radiation exposure in abdominal radiography with digital luminescence radiography and conventional screen-film system: an experimental animal study].

PURPOSE: To determine and compare the minimum required radiation exposure for a.-p. abdominal radiographs with digital luminescence radiography (DLR) and a screen-film system (SFS) providing adequate image quality in clinical routine. MATERIAL AND METHOD: Abdominal radiographs a.-p. of a pig were produced with DLR and SFS systematically varying the tube current-time product. The image quality was assessed by eight experienced radiologists according to the criteria of visual resolution, mean optical density, perceptibility of the lateral edge of the psoas, the caudal edge of the liver, bone structures and intestinal wall. RESULTS: The image quality of the digital radiographs was better for each criterion except visual resolution if the same current-time product was used for both techniques. From the minimum tube current-time products providing an adequate image quality it follows that a dose reduction of 57% can be achieved by applying DLR instead of speed class 200 SFS. CONCLUSION: The recently published guide-lines for quality assurance in x-ray diagnostics issued by the German Federal Board of Physicians recommend using speed class 400 SFS. Since in that case an approximately halved radiation dose is necessary, dose reduction is hardly to be expected with DLR.

Animals↗
PubMed1998

Dose reduction in thorax radiography in simulated neonates with additional filtration and digital luminescence radiography.

PURPOSE: To determine the minimum acceptable radiation dose for an adequate image quality in thorax a.p. radiographs of neonates using mobile X-ray equipment. MATERIAL AND METHODS: The influence of additional filtration (1.0 mm Al + 0.1 mm Cu) on image quality and radiation dose was determined for the speed class 400 screen-film system (SFS) and digital luminescence radiography (DLR) by making radiographs of a test phantom. Conventional and digital thorax a.p. radiographs of a rabbit were produced using various tube current-time products. The quality of the rabbit radiographs was judged by eight radiologists applying image quality criteria according to the German guidelines and the recommendations of the European Community. RESULTS: The added filter resulted in a dose reduction of 39% at 66 kV. DLR gave a further dose reduction of 25% in comparison to the speed class 400 SFS while maintaining adequate image quality, i.e. the radiographs were clinically acceptable with regard to quality criteria. CONCLUSION: The radiation dose resulting from thorax a.p. radiographs of neonates can be reduced by approximately 50% with the use of additional filtration and DLR.

Animals↗
PubMed1991

Radiography transculcitam: technique and devices to simplify bedside radiography.

Bedside chest radiography may be simplified by placement of the cassette under the mattress instead of directly under the patient. With the cassette pressed down into the mattress, a horizontal lateral view can be obtained without having to lift the patient. One technician can use two simple devices to obtain anteroposterior and lateral views, even of a heavy, unconscious patient. A cassette holder for cross-table views of small subjects is also described.

Beds↗
PubMed1993

Variable compensation chest radiography performed with a computed radiography system: design considerations and initial clinical experience.

The authors describe a variable compensation (VC) technique in which an x-ray equalizer and a computed radiography system are used. The VC technique allows retrospective alteration of equalized chest appearance with maintenance of improved signal-to-noise ratio in dense regions. Two imaging plates are used: one upstream of the patient to record the incident beam profile and one down-stream to record the equalized image. Subtraction of a weighted version of the upstream image from the down-stream image permits alteration of the appearance of the VC image, from the extremes of stimulated-unequalized to highly equalized. VC image appearance was optimized with a real-time workstation. The quality of VC images obtained in 33 patients was evaluated by three chest radiologists. Mediastinal appearance was better on VC equalized images than on conventional screen-film images. The stimulation of the appearance of a conventional radiograph with VC proved useful in interpretation of lung appearances on equalized radiographs.

Aged↗
PubMed1992

Portable chest radiography in intensive care: a comparison of computed and conventional radiography.

A prospective study was performed comparing computed and conventional radiography for the detection and visibility of cardiovascular devices in intensive care unit patients. Computed images were obtained using a commercially available 2K x 2K, 12-bit storage phosphor plate system. Image sets from 50 patients were assessed independently by three observers. A significant difference between the types of image was found for the detection of mediastinal drainage tubes and prosthetic valves. Computed images allowed greater confidence in the identification of courses and tips of lines. This advantage was most marked with edge-enhanced computed images.

Adult↗