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PubMed1979

The free focus concept in dental and maxillofacial radiography. The present status of the miniaturized dental x-ray machines.

"Free focus" radiography has shown promise in the examination of complex anatomy in many parts of the body, where conventional and tomographic exposures provide limited information. The approach was introduced in dentistry three decades ago and applied clinically from the time the miniaturized x-ray machines with rod anodes became available in the early 1960's. Yet it has received little attention in the international literature. Recent generations of the unique machines allow free focus surveys of the dentition in two exposures with a film quality comparable to or better than conventional periapical surveys and with a fraction of the radiation load. There is a need for evaluation of such procedures for use in dental practice. Additional applications of free focus radiography promise unusual flexibility in the use x-ray examinations in endodontics, pedodontics, periodontics, and oral surgery, which may justify further development of the miniaturized equipment for such new approaches. Specific suggestions for technical improvements are discussed.

Dental Equipment↗
PubMed1980

A method of determining the sensitometric properties of emulsions and processing techniques used in dental radiography.

The principles and applications of sensitometry in dental radiography are discussed. A method is described for determining the sensitometric properties of films and processing techniques used in dental radiography. This method has been used to demonstrate the relationship between density and exposure for a dental emulsion processed in an automatic processor. Examples of other applications of the method are included.

Absorptiometry, Photon↗
PubMed1983

Free focus radiography with miniaturized dental x-ray machines: a comparison of "midline" and "lateral" techniques.

The use of free focus radiography (FFR) employing miniaturized dental x-ray machines with radiation probes has never been generally accepted in dentistry despite its recognized radiographic potential. The present investigation studied ways to improve imaging and lower radiation burdens in dental free focus radiography. Relatively high air exposures ranging from 42,050 mR per film for high-resolution images to 3,214 mR per film for lower-resolution images using a current midline radiographic technique for panoramic FFR were found. In a proposed lateral FFR panoramic technique, reduced exposures ranged from 420 mR per film for high-resolution images to 14 mR per film for lower-resolution images. In each technique the lower exposure was obtained with a rare earth imaging system. A proposed modification of the current midline FFR technique using a rare earth imaging system and heavy added copper filtration was found to produce exposures in the range normally used in dentistry (207 mr), and the resultant image was high in contrast with relatively low detail. A comparison of essential characteristics of midline and lateral FFR techniques failed to identify specific advantages for the midline technique in current use. Lateral exposure modes in dental FFR should receive increased attention in the interest of good imaging and radiation control. It was noted that existing miniaturized dental x-ray machines may have been designed specifically for use of the midline FFR exposure technique, and modification of this equipment to support reliable lateral exposure modes was recommended.

Miniaturization↗
PubMed1984

Gagging in dental radiography.

The frequency of gagging during full-mouth radiography was evaluated in 478 patients. Gagging was observed in 13% of the patients. The frequency of gagging differed significantly in groups radiographed by trained radiographers and by students (9% and 26%, respectively). Gagging occurred in all regions but most frequently in the maxillary molar area. The technical skill, authority, and self-confidence of the operator were major factors of importance in preventing and suppressing gag reflexes in dental radiography.

Adolescent↗
PubMed1988

Film-holding instruments for intraoral subtraction radiography.

Clinical application of digital subtraction radiography is limited by the reproducibility in the orientation of the x-ray source, image receptor, and object. In this study, eight dental intraoral film alignment instruments (including five replicates of each) were tested for accuracy in repositioning over a period of 6 months. Each instrument was made by adhering one of six impression materials (including acrylics, compounds, and elastics) onto the bite blocks of commercially available alignment instruments. The dimensional accuracy and reproducibility of the orientation of the x-ray source with respect to the object were determined over time for each instrument by measuring the horizontal and vertical angulation change in the position of a buccally placed marker on a dried mandible with a lingually placed film grid. Nine measurements were made during the 6-month test period. The most reproducible instrument was the combination of Regisil, an elastic impression material, and a Rinn XCP bite block. This combination yielded a mean absolute horizontal angulation error of 1.34 degrees +/- 0.63 and a mean absolute vertical angulation error of 2.04 degrees +/- 0.82, yielding a total angulation error of 2.44 degrees +/- 1.16. This was within the acceptable range of accuracy needed to produce diagnostically useful information when digital subtraction radiography is used.

Acrylic Resins↗
PubMed1989

A clinical comparison of image quality and patient exposure reduction in panoramic radiography with heavy metal filtration.

Laboratory and clinical studies with the use of rare earth intensifying screens and four different forms of heavy metal elements serving as additional beam filtration were performed for panoramic radiography to identify the most efficacious system. Balanced density images were evaluated for contrast indices, resolution, relative dose reduction, and subjective image quality. Clinical studies were performed with a standard calcium tungstate imaging system and the four most promising experimental imaging systems that showed improvement over the standard system. Dosimetric studies were performed with the use of ionization chambers and thermoluminescent dosimetry (TLD) dosimeters. Exposure reductions of 34% to 79%, depending on the anatomic site and the imaging system used, were achieved. Subjective image quality was evaluated and analyzed statistically. This study concluded that the use of a Kodak Lanex regular screen/T-Mat G film with either Lanex screen or yttrium added beam filtration results in reduced patient exposure in panoramic radiography while image quality is maintained or improved.

Calcium Compounds↗
PubMed1989

Comparative evaluation of the sensitometric properties of screen-film systems and conventional dental receptors for intraoral radiography.

This investigation determined the sensitometric properties of 27 rare-earth screen-film combinations and compared them to E- and D-speed films and xeroradiography, the current standards for intraoral radiography. A series of exposures from base plus fog to film saturation were made to determine the Hurter and Driffield curve of each image receptor. The base plus fog, film saturation, speed, gamma, average gradient, and resolution were determined. When dental receptors and screen-film systems are compared on the basis of radiographic quality (contrast and resolution), many screen-film systems have similar resolution (greater than 10 line pairs/mm), significantly greater contrast (greater than 2.0), and a substantial speed advantage (greater than 10). Thus selected screen-film systems may be an alternative to conventional dental receptors for intraoral radiography.

Evaluation Studies as Topic↗
PubMed1989

Dental radiography exposure of the Hiroshima and Nagasaki populations.

Dental radiography doses in Hiroshima and Nagasaki were estimated on the basis of survey data from dental hospitals and clinics in Hiroshima and Nagasaki, and doses were measured by thermoluminescent dosimeters and a phantom. Doses to organs, including the lens, pituitary fossa, thyroid gland, and skin were calculated from data obtained during a 2-week survey in both cities. The mean caput doses were calculated from the data indicating frequency per year and were tabulated by organs, age, teeth examined, type of examination, population, sex, and city. No significant difference was observed by age, population, sex, or city. Currently the doses incurred during dental radiography may not be sufficiently high to cause bias in the assessments for late radiation effects among atomic-bomb survivors. However, the mean caput thyroid doses of 62 mrad and 67 mrad in Hiroshima and Nagasaki, respectively, cannot be ignored from the standpoint of their potential in contributing to radiation-induced carcinogenesis.

Adolescent↗
PubMed1990

Diagnostic imaging of diseases affecting the mandible with the use of computed panoramic radiography.

Computed panoramic radiography was performed on patients with bone cyst, osteomyelitis, gingival cancer, and fibrous dysplasia, respectively, to determine the best imaging procedure for disease processes affecting the mandible. Gradational enhancement images for detection of density changes and frequency enhancement images for detecting changes in the margin and texture were effective in aiding the diagnosis of diseases of the mandible with the use of computed panoramic radiography.

Bone Resorption↗
PubMedDate not supplied

Radiography of the eye and orbit: a historical overview.

The history of radiography and orbital imaging begins in 1895 with Wilhelm Roentgen's discovery of x-rays. Over the next three quarters of a century, radiographic pioneers like Dr. William Sweet, who developed the Sweet method, and Dr. George E. Pfahler, who made the first successful pictures of a brain tumor, helped to bring radiography into the 20th century. With each new radiologic innovation producing a forward surge followed by a period of refinement, new methods were invented and utilized to their diagnostic limits. But perhaps none of the radiologic innovations of this century--the Coolidge tube, the Potter-Bucky diaphragm, tomography and angiography-will have more impact than computed tomography and magnetic resonance imaging.

Europe↗
PubMed1993

Diagnostic value of chest radiography for pericardial effusion.

OBJECTIVES: This study was designed to determine the diagnostic value of chest radiography for pericardial effusion. BACKGROUND: Pericardial effusions may cause life-threatening cardiac complications, yet they are often difficult to diagnose. METHODS: In a blinded manner, we reviewed the chest radiographs of 83 patients with echocardiographically diagnosed pericardial effusions (5 large, 18 moderate, 60 small) and those of 17 control subjects without effusions. We examined four radiographic signs: an enlarged cardiac silhouette, a pericardial fat stripe, a predominant left-sided pleural effusion and an increase in transverse cardiac diameter compared with the diameter on a previous chest radiograph. RESULTS: An enlarged cardiac silhouette was moderately sensitive (71%) but not specific (41%) for pericardial effusion. A pericardial fat stripe, a predominant left-sided pleural effusion and an increase in transverse cardiac diameter were all specific (94%, 100% and 80%, respectively) but not sensitive (12%, 20% and 46%, respectively). A predominant left-sided pleural effusion was associated with pericardial effusions of all sizes (odds ratio = 1.3, 95% confidence interval [CI] = 1.0-1.6, p = 0.04) and with large and moderate pericardial effusions alone (odds ratio = 7.7, 95% CI = 2.5-24.0, p = 0.0004). In contrast, a pericardial fat stripe was associated only with large and moderate pericardial effusions (odds ratio = 3.3, 95% CI = 0.9-12.0, p = 0.07), and an enlarged cardiac silhouette and an increase in cardiac diameter were not associated with pericardial effusion at all. CONCLUSIONS: A predominant left-sided pleural effusion and a pericardial fat stripe are chest radiographic signs that are suggestive, but not diagnostic, of pericardial effusion. Because these signs cannot reliably confirm or exclude the presence of pericardial effusion, we conclude that chest radiography is poorly diagnostic of this condition.

Analysis of Variance↗
PubMedDate not supplied

Cervical spine injury and radiography in alert, high-risk patients.

Controversy exists over the need for cervical spine radiographs in alert, nonintoxicated victims of blunt trauma. We identified 286 patients admitted to a Level II trauma center over a 14-month period who were alert (Glasgow Coma Scale [GCS] greater than 13) and considered at high risk for cervical spine injury by published criteria. All 5 (1.7%) fractures or ligament disruptions occurred in the group with neck pain or tenderness. Of the study group, 141 (49%) were asymptomatic for cervical injury and nonintoxicated (blood alcohol concentration (BAC) less than 100 mg/dL). Mandatory cervical spine radiography in this group would have resulted in an additional cost of $33,699. Routine cervical spine radiography in alert, nonintoxicated asymptomatic victims of blunt trauma is a costly practice that warrants further examination.

Adult↗
PubMedDate not supplied

Evaluation of neck discomfort, neck tenderness, and neurologic deficits as indicators for radiography in blunt trauma victims.

Seventeen of 480 adult blunt trauma victims who sustained cervical spine injuries (CSI) were studied prospectively. In reliable patients, complaints of neck discomfort and tenderness demonstrated sensitivities of 86% and 79%, respectively, for CSI. A positive physical examination, defined as neurologic deficits, or cervical region discomfort or tenderness was noted in 13 of 14 reliable individuals sustaining CSI (sensitivity 93%, specificity 16%, positive predictive value 3.3%, negative predictive value 98.7%). Lack of absolute sensitivity of these studied clinical parameters, either singly or in concert, for CSI suggests that eliminating cervical spine radiography on the basis of the absence of neck discomfort, tenderness, or neurological deficits in reliable blunt trauma victims could result in missed CSI. An enormous prospective data base will be required to definitively address the sensitivity of all clinical parameters currently employed to determine the need for cervical spine radiography in reliable blunt trauma victims.

Adolescent↗
PubMed2005

Can follow-up radiography for acute scaphoid fracture still be considered a valid investigation?

AIM: To determine whether follow-up radiography is a valid diagnostic investigation in patients with suspected acute scaphoid fractures and normal initial radiographs. MATERIALS AND METHODS: Fifty sets of radiographs (initial and follow-up) were independently assessed by four expert observers for the presence or absence of a scaphoid fracture. Magnetic resonance imaging (MRI), performed in all cases, was used as the gold standard to determine the sensitivity, specificity, positive and negative predictive values of the observers' assessment of the follow-up radiograph. In addition, the reliability among observers of the follow-up radiograph was determined by reliability variance analysis. RESULTS: Of the 50 sets of radiographs, 35 patients had a scaphoid fracture and 15 were normal, as established from MRI report. For individual observer's assessment of the follow-up radiograph, sensitivities of 11, 9, 43 and 49%; specificities of 93, 93, 87 and 80%; positive predictive values of 80, 75, 88 and 85%; and negative predictive values of 31, 30, 39 and 40%. A reliability coefficient of more than 60% is needed for a diagnostic test to be considered reliable. Overall, the inter-observer reliability coefficient was 33%, with pair-wise inter-observer coefficients ranging from 18-53%. CONCLUSION: With poor sensitivity, poor negative predictive value and poor reliability, follow-up radiography cannot be considered a valid diagnostic examination for the detection of scaphoid fracture in patients with normal initial radiographs.

Adolescent↗
PubMed2006

Specimen radiography as predictor of resection margin status in non-palpable breast lesions.

AIM: This study aimed to evaluate the role of specimen radiography in predicting margin status for non-palpable breast malignancies. METHODS: We retrospectively reviewed the clinical and pathological data together with specimen radiographs of 164 women with ductal carcinoma in situ, who were referred to our centre between January 1997 and December 2000. In all cases microcalcifications were discovered on mammography. Lesions were localized preoperatively using a guide-wire. Specimen radiography findings and clinicopathological data were correlated with pathological findings. RESULTS: Findings comprised 122 pure ductal carcinomas in situ (74%) and 42 mixed carcinomas, both infiltrating and in situ (26%). On the specimen radiographs, the lesions were close (<1mm) to one edge of the lumpectomy in 34 (21%) cases. Histologically, there were 103 positive resection margins (<1mm, 63%) and only 61 negative margins (> or =1mm, 37%). On univariate analysis, factors associated with positive resection margins were found to be distance from microcalcifications to edge of lesion on specimen radiographs, and radiological multifocality. On multivariate analysis (logistic regression), a radiological margin <5mm and multifocality were the only risk factors for close histological margins. Radiological margins were not associated with surgical findings. CONCLUSION: Our results demonstrate that there is a correlation between specimen radiographs and histological results. The clinical relevance of this should be evaluated in a prospective study.

Adult↗
PubMed2005

Comparison of the diagnosis of plain radiography ultrasonography and magnetic resonance imaging in early diagnosis of acute osteomyelitis experimentally formed on rabbits.

PURPOSE: We have compared the sensitivities of MRI, US and radiography which are some of the radiologic modalities used in the early diagnosis of acute osteomyelitis. MATERIALS AND METHODS: After 1 week care and research on 20 New Zealand rabbits (average weight: 2.5 kg) in animal laboratory, study was begun. Six rabbits died after anesthesia and surgical procedure. There were 14 rabbits remaining and 10 of them formed the study group. Four of them were used as the control group. Fresh mouse feces was inoculated into the bone marrow of 20 tibia under general anesthesia and during the following 15 days, MRI, US and radiographic researches were made everyday. RESULTS: According to the results that we got at the end of the 15-day period, MRI was found as the most sensitive method in describing early diagnosis of infection in the bone marrow and also in showing the extension of the infection to the soft tissue. Although US showed the findings later than MRI, it was determined that its sensitivity was less than but near MRI's in detecting subperiosteal fluid in short term period. Radiographic research gives acute osteomyelitis diagnosis latest, so it was determined as the modality that has the lowest sensitivity. CONCLUSION: MRI which is one of the radiologic modalities among other diagnostic radiologic modalities that can be used in early diagnosis of acute osteomyelitis, has the highest sensitivity. Ultrasonography is the second most sensitive modality. Radiographic analysis has the least sensitivity among other modalities. As a result, first MRI then US and after that plain radiography should be used for the early diagnosis of acute osteomyelitis.

Acute Disease↗
PubMed2006

Selective radiography in 100 patients with suspected shoulder dislocation.

We sought to prospectively validate an algorithm for selective radiography in the Emergency Department (ED) management of patients with suspected shoulder dislocation. Physicians ordered pre- and post-reduction radiographs based on an algorithm incorporating the mechanism of injury, previous dislocations, and the physician's clinical certainty of joint position. Follow-up consisted of telephone calls and chart review. Of 100 patients, 94 had shoulder dislocation, and 59% were recurrent. Thirty percent had both pre- and post-reduction radiographs, 45% had pre- or post-reduction only, and 25% had no shoulder films, yielding an overall 46% reduction in X-ray utilization. Mean ED times were significantly shorter for patients managed without radiographs. On telephone follow-up (76%) and chart review (100%), we found no missed fractures or persistent dislocations. Use of a clinical decision rule for selective radiography reduced the number of radiographs and time spent in the ED, while missing no fractures or dislocations.

Adult↗
PubMed2006

Fixed-flexion knee radiography: the sensitivity to detect knee joint space narrowing in osteoarthritis.

OBJECTIVES: Independent reports on the longitudinal performance of non-fluoroscopic fixed-flexion knee radiography have not been published. Therefore, we evaluated the sensitivity of fixed-flexion radiography to detect knee joint space narrowing (JSN) over 2 years in patients with osteoarthritis (OA) and compared the effect of reproducibility and quality of medial tibial plateau (MTP) alignment on sensitivity to JSN. METHODS: Fixed-flexion radiographs of both knees of 193 OA patients were obtained at baseline and after 24 months. Minimum joint space width (JSW) of the medial tibiofemoral joint spaces was measured manually in paired digitised radiographs without knowledge of the chronology. The degree of MTP alignment was assessed by measuring the distance between the anterior and posterior margins of the MTP (intermargin distance [IMD]). Accurate repositioning was achieved if, in the 24-month radiograph, the IMD was reproduced to within 1mm. The quality of MTP alignment was satisfactory if the IMD was <or=1mm. RESULTS: The mean (standard deviation [SD]) JSN between baseline and 24 months was 0.18 (0.49)mm and the standardised response mean (SRM) was 0.37. The SRM was 0.36 in the knee film pairs (86%) in which the IMD was accurately reproduced after 24 months and 0.52 in the film pairs (42%) with satisfactory MTP alignment on both the baseline and 24-month radiographs. CONCLUSION: The sensitivity to radiographic JSN on fixed-flexion knee radiographs over 2 years was higher in satisfactorily aligned than accurately reproduced serial pairs of radiographs. These findings have implications for longitudinal knee OA studies using fixed-flexion radiographs.

Humans↗