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PubMed1989

[Obstetric pelvimetry using digital image intensifier radiography].

Obstetric pelvimetry can be performed by digital image intensifier radiography using very low exposure doses. Comparative measurements show a reduction of the entrance dose to 5% of conventional respectively 15% of high speed film-screen radiography. Phantom measurements have shown an accuracy of +/- 5 mm. In 30 patients the transverse diameter of the pelvic entrance, of the interspinous and of the intertuberous level as well as the sagittal diameter of the pelvic entrance and outlet were measured. Pelvimetry is indicated for the early recognition of certain risks if anamnestic (previous Caesarean section), clinical (eg. external pelvimetry) or fetometric features indicate the evidence of disproportion. As a radiological method the image intensifier radiography appears particularly recommendable in respect of its low exposure dose and the possibility of interactive measurements with subsequent documentation of the diameters and values.

Female↗
PubMed2001

Comparative dose measurements by spiral tomography for preimplant diagnosis: the Scanora machine versus the Cranex Tome radiography unit.

Objective. The purpose of this study was to determine the dose profile of the Cranex Tome radiography unit and compare it with that of the Scanora machine. Study design. The radiation dose delivered by the Cranex Tome radiography unit during the cross-sectional mode was determined. Single tooth gaps in regions 3 (16) and 30 (46) were simulated. Dosimetry was carried out with 2 phantoms, a head and neck phantom and a full-body phantom loaded with 142 thermoluminescent dosimeters (TLD) and 280 TLD, respectively; all locations corresponded to radiosensitive organs or tissues. The recorded local mean organ doses were compared with those measured in another study evaluating the Scanora machine.Results. Generally, dose values from the Cranex Tome radiography unit reached only 50% to 60% of the values measured for the Scanora machine. The effective dose was calculated as 0.061 mSv and 0.04 mSv for tooth regions 3 (16) and 30 (46), respectively. Corresponding values for the Scanora machine were 0.117 mSv and 0.084 mSv.Conclusion. Cross-sectional imaging in the molar region of the upper and the lower jaw can be performed with the Cranex Tome unit, which delivers only approximately half of the dose that the Scanora machine delivers.

Anatomy, Cross-Sectional↗
PubMed2005

Acute knee trauma: analysis of multidetector computed tomography findings and comparison with conventional radiography.

PURPOSE: To evaluate the multidetector computed tomography (MDCT) findings of acute knee trauma and to compare radiography with MDCT in patients referred to a level 1 trauma center. MATERIAL AND METHODS: During a 5-year period, a total of 415 MDCT examinations were performed on 409 patients with acute knee trauma to reveal complex fracture anatomy or rule out a fracture. MDCT and primary radiographs were re-evaluated with respect to fracture location and trauma mechanism. Tibial plateau fractures were further analyzed depending on anatomical location: anterior-medial, anterior-lateral, posterior-lateral, and posterior-medial regions. Maximal depression of the tibial articular surface was measured. Findings on the primary knee radiographs were compared with MDCT findings. RESULTS: Of the 409 patients, 356 (87%) had a knee fracture. A total of 451 fractures were found in all anatomic regions: distal femur (n=49), proximal tibia (n=307), patella (n=23), and proximal fibula (n=72). Primary radiographs were available in 316 (76%) cases. Of these, 225 (71%) had MDCT in order to reveal the fracture anatomy better, and 91 (29%) had a subsequent MDCT after negative plain radiographs. Overall sensitivity of radiography was 83%, while negative predictive value was 49%. On radiography, tibial plateau articular depression was underestimated in all regions except when the fracture consisted of the whole half of the anterior or posterior plateau. The three main injury mechanisms were traffic accident, a simple fall, and sport. In 49 cases (15%), primary radiographs were suboptimal due to positioning. CONCLUSION: In severely injured patients, diagnostically sufficient radiographs are difficult to obtain, and therefore a negative radiograph is not reliable in ruling out a fracture. In these patients, MDCT is a fast and accurate examination and is also recommended in patients with tibial plateau fractures or complex knee injuries in order to evaluate the fracture adequately.

Adolescent↗
PubMed1997

Computed radiography for characterisation of the weight-bearing knee.

PURPOSE: A new method for examining and measuring the weight-bearing knee in computed radiography (CR) and picture archiving and communication systems (PACS) has recently been developed on examination equipment used in QUESTOR Precision Radiography (QPR). QPR is a method for the standardised examination of the knee, and generates 9 angles (e.g. hip-knee-ankle (HKA) angle) and 10 distances, corrected for parallax and magnification. The aim of this present study was to evaluate the reproducibility of this newly developed method and to determine intra- and interobserver variation in its measurements. MATERIAL AND METHODS: The images were generated on a CR system, archived, and transferred to a multimodality work-station that had a monitor with a resolution of 1280x1024 (1kx1k). Photostimulable phosphor plates were used to generate images with a matrix of 1760x2140 pixels (pixel size 0.2 mm, corresponding resolution 2.5 1p/mm). Ten volunteers without knee problems were examined twice, bilaterally, by 2 different radiology technologists. RESULTS: The total reproducibility of the method was good, offering an HKA reproducibility of +/-2.64 degrees in slight flexion and +/-1.62 degrees in extension, at 95% confidence. The intra- and inter-observer variations were low with a reduction of the intra-observer variations in all measurements (except one) by a factor of 2.8 on average compared with the original QPR method for conventional film-screen radiography. CONCLUSION: When QPR is modified for CR, it fulfils the requirement of reproducibility in measurements of the weight-bearing knee.

Adult↗
PubMed2001

Contrast radiography in small intestinal obstruction, a valuable diagnostic tool?

OBJECTIVE: To investigate the diagnostic and therapeutic potential of plain abdominal radiographs and contrast radiography in patients with suspected small intestinal obstruction. DESIGN: Retrospective study. SETTING: General hospital, Sweden. MATERIAL: 2357 sets of plain abdominal radiographic casenotes. MAIN OUTCOME MEASURES: Analysis of plain abdominal radiographs for small intestinal obstruction. Establishment of the time that subsequent contrast radiography medium took to reach the caecum, and its success rate. RESULTS: Of the 2357 plain abdominal films 1599 (68%) did not show small intestinal obstruction, 425 (18%) showed intermediate obstruction, and 333 (14%) showed small intestinal obstruction. The water-soluble contrast medium reached the colon in 394/591 (67%) of the cases with intermediate or complete small intestinal obstruction. Although the contrast medium passed to the colon there was remaining abnormality with dilated small intestine in 71/212 (33%) of the cases with intermediate obstruction and in 95/143 (66%) of the small intestinal obstruction group. The time for the contrast medium to reach the colon was 3.4 hours in the normal group, 5.5 hours in the intermediate group and 8.9 hours in the obstruction group. CONCLUSION: The plain abdominal radiographs seem to predict the success of follow-through examinations. Contrast radiography is safe and may have a therapeutic potential in small intestinal obstruction.

Acute Disease↗
PubMed2003

Imaging of sacroiliitis in early seronegative spondylarthropathy. Assessment of abnormalities by MR in comparison with radiography and CT.

PURPOSE: To analyze the type and frequency of abnormalities of the sacroiliac joint (SIJ) in early seronegative spondylarthropathy (SpA) by MR in comparison with CT and radiography, assess the most appropriate MR sequences to be used, and introduce a new way of grading MR abnormalities of the SIJ. MATERIAL AND METHODS: The SIJs of 41 patients with early SpA (median duration of inflammatory low back pain of 19 months) were evaluated by MR imaging using STIR, T1, T2, and T1 fat saturated (FS) sequences before and after i.v. Gd contrast medium followed by staging of abnormalities. The findings were compared with those obtained by CT and radiography. RESULTS: MR and CT had equal efficacy superior to radiography in staging of erosions and osseous sclerosis. Only MR allowed visualization and grading of active inflammatory changes in the subchondral bone and surrounding ligaments in addition to bone marrow fatty accumulations. T2-weighted sequences did not contribute to assessment of sacroiliitis. CONCLUSION: MR of the SIJs is reliable in its visualization of joint erosions in early SpA and allows differentiation between active and chronic sacroiliitis. We recommend the following sequences: semicoronal T1 and both semicoronal and semiaxial STIR. If these images are normal, the examination can be finished; otherwise additional semicoronal T1 FS before and after i.v. contrast has to be performed as well as semiaxial post-contrast T1 FS.

Adult↗
PubMed1997

Lung findings on high-resolution computed tomography in idiopathic ankylosing spondylitis--correlation with clinical findings, pulmonary function testing and plain radiography.

Previous studies on the association of ankylosing spondylitis and abnormalities of the lung parenchyma have been based largely on plain radiography and pulmonary function testing. This study, although uncontrolled, is the first to use high-resolution computed tomography to examine the entire lung parenchyma in ankylosing spondylitis patients, and to correlate the findings with clinical assessment, plain radiography and pulmonary function testing. The study population comprised 26 patients meeting the New York criteria for idiopathic ankylosing spondylitis who attended the out-patient department at our institution. High-resolution computed tomography examination revealed abnormalities in 19 patients (70%): these included interstitial lung disease (n = 4), bronchiectasis (n = 6), emphysema (n = 4), apical fibrosis (n = 2), mycetoma (n = 1) and non-specific interstitial lung disease (n = 12). Plain radiography was abnormal in only four patients and failed to identify any patient with interstitial lung disease. All patients with interstitial lung disease on high-resolution computed tomography had respiratory symptoms and three of the four had evidence of a restrictive process on pulmonary function testing. This study raises, for the first time, the possible association between interstitial lung disease and ankylosing spondylitis, and highlights the use of high-resolution computed tomography in detecting such disease in ankylosing spondylitis patients.

Adult↗
PubMedDate not supplied

Effect of film graininess and geometric unsharpness on image quality in fine-detail skeletal radiography.

Three direct x-ray films and three geometric conditions were used to study the effect of noise and sharpness on high resolution radiography of the hand. The Wiener spectrum of film graininess and the MTF of geometric unsharpness were measured. Radiographs of a wire mesh and a hand phantom, together with the Wiener spectra and MTFs, led to the following conclusions regarding fine-detail skeletal radiography, as currently employed: 1) bone structure detectable in vivo does not show minute structural detail; 2) the technique is primarily noise-limited; 3) the use of better geometry or finer grain film for improving resolution or noise is of limited practical value, whereas the use of poorer geometry or more noisy film results in appreciable degradation of skeletal images; and 4) the present standard technique for in vivo radiography of the hand, therefore, may be very nearly optimal for clinical applications.

Bone and Bones↗
PubMed1985

Dual-energy projection radiography in the evaluation of femoral neck strength, density, and mineralization.

Two different dual-energy projection radiography techniques were utilized in an attempt to predict femoral neck strength, bone density, and bone mineral content in 19 pairs of cadaver specimens. Positive simple linear correlation was observed between dual-energy scanned projection measurements and dry density, ash fraction, cross-sectional cortical bone area and, to a lesser degree, force required for fracture, but not trabecular bone volume, failure time, or Singh trabecular grade. Dual-energy film radiography was found to be a less reliable indicator of femoral neck strength, density, and mineral content. Dual-energy scanned projection results related linearly to mineral-equivalent solution (K2HPO4) concentration, and demonstrated long-term reproducibility in repeated specimen studies. Correction factors derived to account for differences in femoral size and rotation were shown to be reliable over a moderate range of neck projections. Although bone mineral measurement at other sites may provide comparable or greater information concerning hip fracture risk, dual-energy scanned projection radiography appears to be a useful technique for assessment of bone density, mineral content, and strength in the femoral neck.

Absorptiometry, Photon↗
PubMed1998

Amorphous silicon, flat-panel, x-ray detector versus screen-film radiography: effect of dose reduction on the detectability of cortical bone defects and fractures.

RATIONALE AND OBJECTIVES: The purpose of this phantom study was to assess the diagnostic performance of a self-scanning, solid-state amorphous silicon (a-Si) detector in skeletal radiography using different exposure parameters. METHODS: A flat-panel detector (15 cm x 15 cm), based on a-Si technology with 143 microm x 143 microm pixel size, 1k x 1k matrix, and 12 bit digital output was used. State-of-the-art screen-film radiography (SFR; speed 400, detector dose 2.5 microGy) was compared with a-Si images taken at doses that were equivalent to a speed of 400, 800, 1,250, and 1,600, respectively. A total of 232 segments of long tubular deer-bones (femur, tibia, humerus, radius) had 110 artificial fractures and 112 cortical defects simulating osteolytic lesions. Receiver operating characteristic analysis was performed for 9,280 observations made by four independent observers. Two-tailed Student's paired t test was used for statistical analysis (95% confidence level). RESULTS: Receiver operating characteristic analysis yielded equivalent results of the a-Si and SFR system. Even at the lowest dose there were no statistically significant differences between both imaging modalities with respect to the detectability of fractures and cortical defects. CONCLUSIONS: The results of this study indicate that a-Si detector technology holds promise in terms of dose reduction in skeletal radiography without loss of diagnostic accuracy.

Animals↗
PubMed2000

Digital radiography with a large-area, amorphous-silicon, flat-panel X-ray detector system.

RATIONALE AND OBJECTIVES: To investigate the image quality of a digital radiography system with an amorphous-silicon, large-area, digital flat-panel detector. METHODS: A flat-panel detector based on a matrix of amorphous silicon was integrated into a projection radiography system. The scintillator consisted of a layer of structured cesium iodide. The active matrix size of 30002 pixels together with a pixel size of 143 microm provided a large image area of 43 x 43 cm2. Basic image quality parameters such as detective quantum efficiency (DQE) and modulation transfer function (MTF) were measured and compared with those obtained with conventional systems. RESULTS: The measurement of DQE yielded a high value of 70% at zero spatial frequency. At a system dose equivalent to 400 speed, the DQE of the digital system was a factor of two larger than the DQE of a storage phosphor or screen-film system within the entire spatial frequency range between zero and the Nyquist limit of 3.5 line pairs per millimeter. The flat-panel detector furthermore has an MTF that is superior to that in regular screen-film systems and also provides a substantially larger dynamic range. CONCLUSIONS: This new technology demonstrates its potential to provide equal or superior image quality to conventional screen-film systems and to reduce patient exposure to radiation dose. The advantages of digital radiography systems, based on a flat-panel detector as an instant image display, facilitation of work flow in the radiology department, and digital networking and archiving, are well in sight.

Humans↗
PubMed1982

Radiographic blood pool contrast agents for vascular and tumor imaging with projection radiography and computed tomography.

An emulsion of Ethiodol and Pluronic was evaluated as a vascular (blood pool) imaging agent with both the GE experimental scanned projection radiography system and conventional computed tomography (CT), 475 mg iodine/kg body weight of emulsion, was injected into 11 rabbits with thigh muscle V2 carcinomas. Both projection radiography scans and CT scans visualized aorta, vena cava, pulmonary, and femoral vessels, and distorted vessels around tumors for 20 min after infusion. This persistent vascular visualization allowed CT scanning at multiple contiguous levels, which could be followed by reformatting in the sagittal and coronal planes. Following diatrizoate in identical iodine/kg doses, vascular visualization persisted for only 1 min after infusion. Blood pool agents are ideal for projection radiography systems and CT reformatting of vascular anatomy.

Angiography↗
PubMed1999

Sensitivity of noncontrast helical computerized tomography and plain film radiography compared to flexible nephroscopy for detecting residual fragments after percutaneous nephrostolithotomy.

PURPOSE: We prospectively compared plain film radiography and noncontrast, thin cut helical computerized tomography (CT) to flexible nephroscopy for detecting residual stones after percutaneous nephrostolithotomy. MATERIALS AND METHODS: We prospectively evaluated 36 patients (41 renal units) undergoing percutaneous nephrostolithotomy for large (greater than 3 cm., 23 renal units) or staghorn (18 renal units) calculi. All patients underwent postoperative imaging with plain film of the kidneys, ureters and bladder and noncontrast helical CT, and flexible nephroscopy on postoperative day 2 or 3. The size and location of residual fragments determined radiographically and identified by flexible nephroscopy were compared. RESULTS: Plain film radiography and CT detected an average of 0.7 and 3.4 stones per renal unit, respectively. With a mean operating time plus or minus standard deviation of 77.3+/-35 minutes and a mean fluoroscopy time of 7.6+/-6.7 minutes, an average of 2.3 stones per renal unit were retrieved at flexible nephroscopy. In 90.2% of renal units all calices could be directly inspected. The sensitivity and specificity were 46% and 82% for plain film radiography, and 100% and 62% for CT, respectively, using flexible nephroscopy as the gold standard for detecting residual stones. The overall stone-free rate after flexible nephroscopy was 92.6%. The cost of this procedure is $5,625.13 compared to $220 for CT, including the interpretation fee, at our institution. CONCLUSIONS: Selective use of flexible nephroscopy after percutaneous nephrostolithotomy based on positive CT findings will avoid an unnecessary operation in 20% of patients. The rate of unnecessary procedures is 32% if all patients undergo flexible nephroscopy, regardless of radiographic findings. At our institution this strategy will result in a cost savings of $109,687 per 100 patients.

Costs and Cost Analysis↗
PubMed1994

Low-dose radiography of scoliosis in children. A comparison of methods.

STUDY DESIGN: Records of 1,582 conventional and computed radiographic examinations performed to evaluate scoliosis were reviewed and compared to determine differences in total radiation burden. OBJECTIVE: This study evaluated the impact of computed radiographic imaging (CRI) on radiation exposure in children undergoing serial spinal radiographs for scoliosis assessment and compared exposure from CRI with that of low-dose film-screen combinations. SUMMARY OF BACKGROUND DATA: CRI permits diagnostic radiographic studies to be performed with a dose reduction of 80%-95% compared to conventional film-screen systems. High speed film-screen systems also permit a significantly lower exposure. Each approach has unique advantages and disadvantages. METHODS: Over 6 years, we performed 1,582 spinal examinations in children 4-14 years old using reduced dosage techniques with computed radiography. The images were obtained with Fuji FCR 101 and Philips PCR/SP systems. The adequacy of diagnostic image quality in the serial evaluation of scoliosis at different exposure levels was evaluated and compared with regular and film-screen systems with speeds ranging from 250 to 1,200. RESULTS: Diagnostic-quality images for evaluating scoliosis can be obtained with doses of 5% or less than required with conventional film-screen systems. Computed radiography provides image quality and dose reduction comparable to a 1,200-speed film-screen system. CONCLUSION: CRI gives satisfactory images at 5% reduction of the standard film-screen dose. Based on comparison with a 1,200 speed film-screen system, CRI provides equal or better image quality at a similar radiation dose. The cost of CRI is higher than for film-screen radiography, but wide latitude and the ability to tailor dose with requirements for image quality are significant advantages for CRI.

Adolescent↗
PubMedDate not supplied

Digital radiography in pediatric orthopaedics: a prospective, controlled, and randomized trial.

A prospective, controlled, and randomized trial of digital radiography was conducted to evaluate its advantages in children. Matched pairs of radiographs of the feet were taken in 20 children, and pelvic radiographs were taken in another 20 children. Each pair comprised a digital and conventional film. Half of the digital films were made with a 50% radiation dose reduction. The films were scored for quality. Statistically significant advantages were seen for the digital radiographs as compared with the conventional technique. Visualization of soft tissue and bony detail was enhanced in both foot and pelvic radiographs. This was true even with a 50% dose reduction in many of the parameters scored. We conclude that digital radiography offers advantages over conventional radiography, and recommend its use.

Child↗
PubMed1992

Digital subtraction radiography for assessment of simulated root resorption cavities. Performance of conventional and reverse contrast modes.

A previous study of the sensitivity and accuracy of a standardized radiographic technique for the disclosure of root cavities in a cadaver material indicated that it was not possible to perceive small artificial "resorption" cavities. Using the same material, the aim of the present study was to evaluate whether the use of subtraction radiography would improve the detection of root cavities. In an autopsy material of five mandibular blocks each containing two premolars, small, medium, and large cavities were drilled in the cervical, middle, and apical thirds of the proximal and oral root surfaces. Each jaw block was radiographed before (B) and after (A) cavity preparation with three different exposure times resulting in light, medium, and dark film densities. The radiographs were digitized. Digital subtraction was performed between the A- and B images of varying densities by a computer program developed for dental subtraction radiography. Conventional and reverse contrast modes of the subtraction image were assessed independently by four observers. The results showed small inter- and intraobserver differences in diagnostic accuracy for assessment of total number of root cavities. Original film density did not influence the diagnostic performance in the resulting subtraction image. Contrast mode in the subtraction image influenced diagnostic performance as the majority of observers did best with the reverse contrast mode (p < 0.05). Some of the small root cavities were disclosed by the subtraction technique, but overall accuracy was not increased compared to conventional radiography.

Humans↗
PubMedDate not supplied

Pet fish radiography: technique and case history reports.

Radiography can be used to aid in the diagnosis and treatment of pet fish diseases. Handling, restraint and radiographic technique for the radiographic examination of pet fish is described. Quality diagnostic images can be obtained with standard radiographic equipment and radiographic techniques. Fishes with undifferentiated sarcoma, swim bladder herniation and scoliosis are three clinical examples that are described where radiography was used in the management of the patient. Conventional radiography appears to be best for evaluating skeletal and swim bladder diseases. Alternate imaging techniques such as computed tomography and magnetic resonance imaging may enhance the evaluation of coelomic soft tissue structures.

Air Sacs↗
PubMed2002

Quantification of the effect of kvp on edge-enhancement index in phase-contrast radiography.

This study was performed to measure the dependence of edge-enhancement in polychromatic phase-contrast radiography on x-ray tube operating voltage. Measurements of edge enhancement were made at tube voltages from 40 to 86 kVp using a tungsten anode x-ray tube with a nominal focal spot size of 100 micrometers. A relatively weak attenuating, sharp edge consisting of a thin lucite sheet (3 mm) in air was imaged utilizing phase-contrast radiography (PC-R). PC-R images were acquired at different radiographic techniques in which x-ray tube voltage was varied from 40 to 86 kVp. The image receptor was a single emulsion x-ray mammography cassette. Optical density profiles across the edge of the object were obtained using a film digitizer and edge-enhancement indices were calculated. Increasing kVp resulted in a gradual decrease of the edge-enhancement index. Even at the highest kVp (86), however, important edge-enhancement effects were evident. While there is some degradation in the edge-enhancement effect of phase-contrast radiography at higher kVps, the decrease from 40 to 86 kVp is relatively small (11%). Our results suggest that further investigation into the role of phase-contrast imaging at higher kVp values for the purpose of patient dose reduction while still realizing the advantage of phase-contrast effects for improved soft-tissue detectability is warranted.

Image Processing, Computer-Assisted↗