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PubMed1990

Newer imaging methods in chest radiography.

In recent years the application of computers to chest radiography has resulted in a wide variety of innovative research. Major research efforts have resulted in the development of new types of x-ray detectors, such as storage phosphor technology, for use with computers. Storage phosphor imaging is one of the most promising new techniques, and almost 100 systems have been installed worldwide. Radiologists are quickly evaluating the image quality provided by this new detector system, which has the potential to improve image quality. It has wide latitude and is coupled with a computer to perform image processing. Another promising technology, originally studied in the form of scan equalization radiography, is now commercially available in the form of advanced multiple-beam equalization radiography. This film technique uses computers to modulate the x-ray exposure to take maximum advantage of the imaging capabilities of radiographic film. Digital solid-state detectors have been studied in conjunction with computerized image enhancement systems. These currently show improvement in nodule detection and quantification of the calcium content of a lesion. Application of large image intensifiers to a digital image system is being studied, but there are currently limitations on spatial resolution.

Health Services Research↗
PubMed1990

Current status of digital projectional radiography of the chest.

Thoracic imaging constitutes more than one-third of all medical imaging performed in the United States. Despite the substantial impact of computer technology in other areas of imaging, conventional film-screen acquisition systems still provide the bulk of projectional chest radiography. The successful implementation of digital technology in thoracic imaging requires that the standards of current film-screen methods for both diagnostic accuracy and efficient data management be preserved. This article addresses the technical and clinical aspects of film digitization and storage phosphor technology, which are the two digital acquisition systems in widest application. Scanned projection radiography, which may now be applied to computed radiography systems, is also discussed. Finally, some of the issues surrounding the implementation of picture archiving and communication systems for thoracic imaging are addressed.

Adult↗
PubMed1996

Results of three-phase bone scintigraphy and radiography in 20 cases of neonatal osteomyelitis.

Neonatal osteomyelitis, a rare, potentially crippling disease, requires early diagnosis and effective therapy. This study of 20 neonates analysed the diagnostic value of three-phase bone scintigraphy (motivated by its controversial role), plain radiography and local clinical signs in neonatal osteomyelitis and complicating septic arthritis. The sensitivities for detecting focal skeletal involvement were as follows: bone scintigraphy 90%, radiography 65%, clinical local signs 20%. Reliable scintigraphic signs were localized hyperperfusion (phase I), vasodilation (phase II) and hot or cold lesions on 3-h images. Radionuclide angiography definitely increased the validity of bone scintigraphy. During follow-up, the reduction or normalization in focal hyperperfusion was the first and most sensitive sign of an adequate response to antibiotic treatment; persistence (or recurrence) of focal hyperperfusion, increasing relative uptake ratios and the appearance of new foci of bone involvement indicated escape from antibiotic therapy. Radiography revealed no pathological signs in 35% of cases, soft tissue changes in 20% and effusion of the hip joint in 45%. Local clinical signs were not a reliable predictor of scintigraphic or radiographic findings. We consider bone scintigraphy in neonatal osteomyelitis to be a successful, efficient and cost-effective diagnostic modality, not only for early diagnosis, but also during follow-up.

Bone and Bones↗
PubMed1998

Clinical criteria for using radiography for children with acute knee injuries.

OBJECTIVE: To evaluate clinical criteria for selective radiography for knee injuries in children. DESIGN: Retrospective chart review. SETTING: Emergency department (ED) of a children's hospital. PARTICIPANTS: All patients evaluated by radiography for an isolated, acute knee injury during 12 months. Patients were excluded for injuries: >1 week; isolated to superficial lacerations/abrasions; with prior knee surgery; being reassessed. RESULTS: Two hundred fifty-four patients (60% male; 12.7 years median age) were included. Twelve patients (4.7%) sustained a fracture. Evaluated criteria were point tenderness, inability to bear weight in the ED, and inability to flex the knee to 90 degrees. Point tenderness was not statistically associated with fracture, P = 0.7. Inability to bear weight in the ED (37% fracture rate, P = 0.001) and inability to flex to 90 degrees (52% fracture rate, P < 0.001) were associated with the presence of fracture.[table in text] Applying a rule combining nobearwt and noflex90 would decrease the number of x-rays by 73%, with no missed fractures. CONCLUSIONS: Point tenderness was not a good predictor of knee fracture in children. Using the clinical criteria to select patients requiring knee radiography may greatly reduce the number of unnecessary x-rays.

Acute Disease↗
PubMed1999

Is stress radiography necessary in the diagnosis of acute or chronic ankle instability?

BACKGROUND: Clinicians often use the talar tilt (TT) and anterior drawer (AD) stress x-rays to diagnose acute or chronic mechanical ankle instability. However, the wide range of TT and AD values in normal and injured ankles makes interpretation of the test results difficult. OBJECTIVE: To critically review the literature and determine the accuracy of stress radiography in the diagnosis of mechanical ankle instability. DATA SOURCES: MEDLINE was searched for relevant articles published since 1966 using MEDLINE subject headings (MeSH) and textwords for English articles related to ankle injuries and radiography. Additional references were reviewed from the bibliographies of the retrieved articles. The total number of articles reviewed was 67. Of these, 8 studies met criteria for inclusion and were analyzed. STUDY SELECTION: Only clinical studies that used surgical exploration as the gold standard for diagnosing lateral ligament rupture were evaluated for this study. Cadaver or laboratory studies were excluded. DATA EXTRACTION AND SYNTHESIS: In reviewing the literature, pertinent strengths of the different study designs were emphasized. From these data, particular attention was paid to the diagnostic accuracy of each study in comparing TT and AD stress x-rays to surgical confirmation of lateral ligament rupture. MAIN RESULTS: A total of eight prospective clinical series satisfied the inclusion criteria. Seven of the eight assessed acute ankle instability as the outcome and one assessed chronic ankle instability. Of the seven studies that focused on acute ankle injuries, only one concluded significant benefit in using stress views to diagnose lateral ligament rupture. Three of the seven reported a positive relationship between stress radiography and surgical findings, although all six studies concluded that TT and AD stress x-rays are not reliable enough to make the diagnosis. The authors who assessed chronic ankle instability stated that TT and AD stress views combined were not useful in defining ankle instability. CONCLUSION: The published data regarding TT and AD stress x-rays are too variable to determine accepted normal values compared with injured values. There are insufficient data for comparison of the use of mechanical versus manual techniques, or use of local anesthetic to facilitate the stress test. Because the treatment evolution of all acute ankle sprains is toward functional nonoperative treatment and because treatment does not depend on the degree of ankle instability on stress views, the TT and AD stress x-rays have no clinical relevance in the acute situation. In cases of chronic instability, the large variability in TT and AD values in both injured and noninjured ankles precludes their routine use.

Acute Disease↗
PubMed2005

Ineffectiveness of routine abdominal radiography in patients with gastrointestinal hemorrhage admitted to an intensive care unit.

GOALS: To determine the utility of plain abdominal radiography in the initial evaluation of acute gastrointestinal (GI) hemorrhage in a medical intensive care unit. BACKGROUND: Plain abdominal radiographs are frequently used in the routine evaluation of patients with GI bleeding. The utility of these studies in the intensive care unit setting is unclear. STUDY: The study was a retrospective chart review of 71 adult subjects admitted to a medical intensive care unit with the diagnosis of GI bleeding. Subjects were excluded if they presented with peritoneal signs, received an abdominal CT scan in the 24 hours prior to admission, or were chronically treated with immunosuppressive medication. Subjects were divided into two cohorts based on whether or not they underwent plain abdominal radiography during the first hospital day. The primary study endpoints were hospital mortality, intensive care unit length of stay, and whether or not radiographic findings altered clinical management. RESULTS: Of the 71 patients admitted with a diagnosis of GI bleeding (mean age 65.8 +/- 14.5 years, 73.2% male), 56 (79%) had a plain abdominal radiograph performed. Subjects who had a plain film did not differ significantly from those who did not in age, gender, degree of anemia, degree of coagulopathy, or in severity of illness as measured by Acute Physiology and Chronic Health Evaluation (APACHE II) score. There was no statistically significant difference in hospital mortality or intensive care unit length of stay between patients who received plain films and those who did not. In no subject (0%; 95% confidence interval, 0%-5.4%) did abdominal radiography reveal an abnormality that altered clinical management. CONCLUSIONS: Based on our observations, plain films of the abdomen do not appear to alter clinical outcomes or management decisions for patients with GI bleeding and normal abdominal examinations who are admitted to the intensive care unit.

Aged↗
PubMed1996

The use of a radiopaque contrast medium in endodontic radiography.

A series of in vitro studies were carried out to investigate the use and application of a radiopaque contrast medium in conventional periapical dental radiography for the diagnosis and evaluation of root canal systems. The water-soluble radiopaque contrast medium was introduced into the root canals of 30 first permanent maxillary and 30 first permanent mandibular molar teeth. The radiographic images of these teeth with and without radiopaque contrast medium in the root canal systems were compared and contrasted. Further comparisons were made with the same teeth rendered transparent. The results indicate that by standardizing the diagnostic criteria the inter-examiner reliability was in good agreement; it was independent of the radiographic technique used. The validity of the radiographs was enhanced by the use of the radiopaque contrast medium. The results confirm that, with the use of a radiopaque contrast medium, images of root canal systems are easier to read and interpret than plain radiographic images of root canal systems. The use of radiopaque contrast medium in endodontic radiography may be a valuable aid in the diagnosis and evaluation of root canal systems. This system would complement rather than replace plain radiography.

Contrast Media↗
PubMed1998

Microfocal radiography in the diagnosis of childhood renal osteodystrophy.

BACKGROUND: Renal osteodystrophy is common in children with chronic renal failure (CRF) and X-ray is an intensive method in the diagnosis of the disease. In this study we compared microfocal radiography with conventional method for the diagnosis of renal osteodystrophy. METHODS: The X-rays of left wrists of 21 children with CRF and chronic renal insufficiency were taken by conventional and microfocal methods. RESULTS: Both methods revealed osteopenia in all patients (100%), widening, fraying and cupping of ulnar and radial metaphysis in 10 (47.6%), osteosclerosis in three (14.2%) and pseudofracture in one (4.7%) patient. Microfocal radiography demonstrated osteosclerosis in one patient, pseudofracture in four and subperiosteal resorption in five patients that were not detected by conventional method. CONCLUSION: Two methods were found to be significantly different in demonstrating the changes due to rickets and hyperparathyroidism and it is concluded that microfocal radiography may be preferred in the diagnosis of childhood renal osteodystrophy.

Adolescent↗
PubMedDate not supplied

Nuclear medical bone imaging and targeted radiography for evaluation of skeletal neoplasms in 23 dogs.

Nuclear medical bone imaging was used in combination with targeted radiography to detect metastatic or multicentric lesions in 23 dogs with skeletal neoplasms. Each dog with a radiographically diagnosed skeletal neoplasm was injected with Technetium-99m labeled methylene diphosphonate (99mTc-MDP) (15.0 mCi intravenously) for whole body imaging. All areas with increased uptake of 99mTc-MDP were radiographed. In 19 dogs, the amount of bone shaft involvement in primary sites indicated by bone imaging was larger than the amount indicated by radiography. Eighteen dogs had secondary areas of increased 99mTc-MDP uptake, six of which had secondary areas that were suspected radiographically to be neoplastic. Four dogs had lesions characterized histologically as neoplasia, one as bone infarction and one as normal cortical bone. Positive predictive value for this strategy was 66.7%. Results of this study suggest that nuclear medical bone imaging with targeted radiography is a quick, noninvasive technique with a good positive predictive value for evaluation of the skeleton for metastatic or multicentric sites of neoplasia.

Animals↗
PubMed1994

Prediction of the need for bitewing radiography in detecting caries in the primary dentition.

In recent literature some controversy has been reported regarding the prescription of bitewing radiography for caries diagnosis, particularly in children. While the low prevalence of caries justified the decision not to take radiographs, it has also been reported that the benefits of detecting slowly progressing, clinically undetectable lesions could outweigh the "costs" of radiography. It was the aim of this study to investigate whether specific risk factors could predict the presence of additional dentinal lesions (ADL) in the primary dentition on radiographs which could not be detected by visual inspection. Bitewing radiographs were taken in 182 children aged 5 yr. Risk factors for ADL were identified and appropriate rating scales were designed. Sensitivities, specificities and relative risks expressing the relation between scale values and ADL were computed for each of the risk factors and direct and stepwise discriminant analyses were performed. The results indicate that particularly the presence of lactobacilli and mutans streptococci in saliva and the detection of three or more discolored enamel lesions or dentinal lesions were good predictors of ADL. It is suggested that these risk factors be used in the timing of bitewing radiography in children with a primary dentition.

Child, Preschool↗
PubMed1996

Factors influencing the frequency of bitewing radiography in general dental practice.

The aim of this study was to determine the influence of a range of patient and dentist factors on the prescription of bitewing radiography. A postal questionnaire of general dental practitioners working in the Birmingham and Manchester areas of England was used. Dentists were requested to score the influence of 15 factors upon their decision whether or not to take bitewing radiographs. Some of these factors were chosen to represent accepted "high caries risk" factors, some "low risk" factors, while others were chosen as they should be irrelevant to prescription of bitewing radiographs. There was a questionnaire response of 70.8%. Dentists recognized accepted high caries risk factors as being an indicator for bitewing radiography but the influence of low caries risk factors was less clear. Only "good oral hygiene" and the presence of "few restorations" were perceived as relevant to bitewing prescription, while fissure sealants were seen as an influence in favour of radiography by almost one third of dentists. Dentists tended to be influenced in their radiographic practice by the opinions of patients and fears of medico-legal consequences. Pregnancy was seen as contra-indicatory for bitewings by almost all dentists. These results suggest that greater emphasis should be placed upon radiographic selection criteria in dental education.

Adult↗
PubMed2004

Students' attitudes to digital radiography and measurement accuracy of two digital systems in connection with root canal treatment.

The aim of this study was to evaluate students' attitudes towards digital radiography and measurement accuracy in digital images recorded with a CCD-sensor and a photostimulable phosphor (PSP) plate radiography system in connection with root canal treatment. Thirty-one dental students participated in an endodontic course. Two single-rooted teeth were assigned at random to two receptors for digital radiographic examination, either (i) the RVG-ui CCD sensor or (ii) the Digora PSP plate system. After the endodontic treatment had been completed for the first tooth, the student filled in a questionnaire on their use of the digital system. Thereafter, the students switched radiography system and repeated the procedure for the second tooth. Eventually, the students completed the questionnaire by answering questions that directly compared the two digital systems. The gutta-percha filled tooth was measured using the system's own software. Two measurements of each tooth were performed: total tooth length (TTL) and root filling length (RFL). The teeth were dismounted from the plaster blocks and the true TTL and RFL was measured with an electronic slide calliper. The majority of the students had used the contrast enhancement facility (CCD sensor = 52%, PSP = 71%) and the zoom facility (65-68%) whilst some had used the density enhancement facility (CCD sensor = 39%, PSP = 55%). The students stated that they saved more time when they used the CCD sensor than when they used the PSP system (P < 0.001), and that it was easier to position the tooth with the PSP plate than with the sensor (P < 0.01). The lengths measured on the digital images from both digital systems were marginally larger than the true tooth lengths (P < 0.05). However, there was no difference between the two digital systems for the TTL/RFL ratio (P > 0.05).

Dental Pulp Cavity↗
PubMed1998

A digital subtraction radiography investigation of upper first molar proximal bone density changes in adolescents.

The aim of this in vivo study was to investigate the ability of digital subtraction radiography to monitor changes in proximal bone density, adjacent to the upper first molars, in a group of adolescents using the Digora direct digital radiographic system to acquire images. For 57 adolescents, assessments of changes in probing attachment level at the mesio- and disto-buccal surfaces of both upper first molars and proximal crestal bone density using digital subtraction radiography were made. At the conclusion of this 21-month study attachment loss was identified in 34 (17%) of the 204 sites analysed. For sites with attachment loss a mean decrease in bone density equivalent to 5.51 mm3 aluminium (Al) was found compared to 2.96 mm3 Al for those without (p < 0.001). For the 17 subjects with attachment loss a mean equivalent to 4.66 mm3 Al was lost from the crestal bone compared with 2.56 mm3 Al for the 40 subjects without attachment loss (p < 0.01). The correlation between attachment loss and bone density changes was poor for both sites (r = 0.13), p = 0.067) and mean scores for subjects (r = 0.24, p = 0.069). A visual qualitative assessment of bone density change found that 70.6% of sites with attachment loss compared to 62.4% of those without had a decrease in crestal bone density. This study suggests that it is possible to monitor bone density changes in adolescents, with a developing dentition, using digital subtraction radiography. Further, it is suggested that conventional probing assessments of attachment level may underestimate the level of destructive periodontal disease in this age group.

Adolescent↗
PubMed1995

Diagnostic value of chest radiography and electrocardiography in the evaluation of asymptomatic children with a cardiac murmur.

We investigated the diagnostic value of the chest radiograph and ECG in the evaluation of whether asymptomatic children with a cardiac murmur had a heart disease as defined by echocardiography. One hundred children aged 1 month to 15 years (median 30.1 months) were included. After physical examination, a tentative diagnosis was made: 53 children had no heart disease, 24 had a probable heart disease and 23 children were thought to have heart disease on the basis of clinical assessment alone. After information from chest radiography and electrocardiography was obtained, the diagnoses were re-evaluated. This resulted in a change of the tentative diagnosis in three children. However, the diagnosis in relation to the definite diagnosis by colour Doppler echocardiography was not changed to the correct diagnosis in any of these cases. In 24 cases, radiography suggested the presence of heart disease; however, only 10 of these had heart abnormalities on the colour Doppler echocardiogram (CDE). Three children had an abnormal ECG; all of these had abnormalities on the CDE, but they were already diagnosed as having heart disease by physical examination. We conclude that chest radiography and electrocardiography is of no help in the discrimination between heart disease and no heart disease in asymptomatic children referred for a cardiac murmur.

Adolescent↗
PubMedDate not supplied

Survey of the use of radiography vs. ultrasonography in the investigation of gastrointestinal foreign bodies in small animals.

A question frequently asked by clinicians who are treating small animals suspected of having gastrointestinal foreign bodies is whether one imaging test such as survey radiography or ultrasonography is sufficient to make the diagnosis. A study was undertaken to try and answer this question. Survey abdominal radiography and ultrasonography was performed on 16 small animals (11 dogs, five cats) with clinical signs of an obstruction because of a confirmed gastrointestinal foreign body. The majority of the foreign bodies (14/16) were confirmed by surgical removal and were located in the small intestine. A gastric foreign body was retrieved endoscopically and a colonic foreign body was passed in the feces. Radiographically identifiable foreign bodies were evident in nine animals. Small intestinal overdistension was present radiographically in seven animals. Ultrasonography detected a foreign body in all 16 animals. The foreign bodies were identified by their distal acoustic shadowing and variable degrees of surface reflection. An intestinal perforation was detected sonographically but not radiographically. The value of additional sonographic findings including thickening of the gastrointestinal wall and loss of layering, free peritoneal fluid, and lymphadenopathy in these animals is discussed. The findings in this series suggest that in a small animal with a gastrointestinal foreign body, ultrasonography alone could be used to make the diagnosis and may be a more appropriate choice than survey radiography.

Animals↗
PubMed2004

Determination of dose-area product from panoramic radiography using a pencil ionization chamber: normalized data for the estimation of patient effective and organ doses.

The aims of the present study were (a) to investigate the potential of pencil ionization chamber to be used for the determination of dose-width product (DWP) and dose-area product (DAP) from panoramic radiographic exposures and (b) to provide data normalized to DAP for the determination of patient effective and gonadal dose from panoramic radiography performed in any laboratory. A pencil ionization chamber commonly used to measure CT dose index (CTDI) in CT scanners was employed to determine DWP for various combinations of panoramic exposure settings at the beam exit slit of a Cranex Tome panoramic x-ray unit (Soredex, Helsinki, Finland). DWP values were also measured using an array of thermoluminescence dosimeters. Reproducibility of the DWP measurement was tested. The effect of milliamperage and kilovoltage of panoramic exposures on DWP was investigated. DAP was estimated using the value of DWP measured using the pencil ionization chamber and the beam exit slit length measured using dosimetric film attached on the beam exit slit. A Rando anthropomorphic phantom appropriately loaded with thermoluminescent dosimeters (TLDs) was used to obtain organ dose and effective dose values from panoramic radiography. Reproducibility of DWP determination using the proposed method was better than 1.5%. DWP was found to be linearly related to milliamperage (r>0.999, p<0.001) and to kilovoltage raised in a power ranging from 2.18 to 2.55. DWP measured using the pencil chamber was found to be up to 11% higher than the corresponding values determined using TLD array. The panoramic exposure obtained with settings appropriate for the typical adult patient was found to result in 0.008 mSv patient effective dose, 0.0002 mGy gonadal dose, and 11.3 cGy cm2 DAP. The use of a pencil ionization chamber is proposed for the determination of DWP and DAP from panoramic radiographic exposures. Normalized data over DAP were provided for the determination of patient effective and gonadal dose from panoramic radiography.

Body Burden↗
PubMedDate not supplied

A method for selective tissue and bone visualization using dual energy scanned projection radiography.

Information contained in the x-ray energy spectrum can be used to produce selective radiographic images of bone or soft tissue. A method has been devised to separate bone and soft tissue based upon differences in photoelectric absorption and Compton scattering using an appropriate combination of images obtained with radiographic exposures at 70 KVP and 140 KVP. Since photoelectric absorption is highly dependent upon atomic number, high atomic number materials such as calcium can be easily separated from water density substances. Using a prototype system for line-scanned radiography, selective subtraction of bone or soft-tissue has been implemented. Because this method uses a conventional broad-spectrum x-ray source, it was necessary to develop a nonlinear polynomial approximation to estimate tissue and bone thickness. The model was verified with phantom studies using water and aluminum. The application of this dual-energy bone and soft-tissue separation to chest radiography is demonstrated. This method allows accurate estimation of tissue and bone thickness and should find application to chest radiography for improved lesion detection and for bone mineral assessment.

Animals↗
PubMedDate not supplied

A xenon ionization detector for digital radiography.

Xenon gas x-ray detectors have been used successfully in CT scanners; however, they have been found to be unsuitable for digital radiography. We have designed and built a new type of xenon x-ray detector array and tested its suitability for digital radiography. The detector consists of two parallel plates separated by a 0.5-mm gap, filled with xenon gas at a pressure of about 30 atm. One of the plates is the high-voltage electrode, while the other is a circuit board etched to form an array of metal collector strips focused on the x-ray source. Since there are no metal septa separating the individual detector elements, the dose efficiency of the detector is high, but image degradation will occur due to cross-talk between detector elements. Measurements of the cross-talk show that about an 18% reduction in contrast will occur, when a low contrast object, subtending one detector element, is imaged. We have also measured a detector MTF of 14% at 2 lp/mm, a signal of 10 pC for a 1-mR x-ray exposure at the detector entrance, a 6% nonlinearity in the detector signal over about 3 orders of magnitude in x-ray exposure, and a charge collection time (time response) of about 0.1 ms. From these results it is concluded that this new detector design is feasible for digital radiography.

Computers↗