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PubMed1992

Subtraction radiography of interradicular bone lesions.

Subtraction and conventional radiography were evaluated for their diagnostic potential to assess interradicular bone lesions in the mandibular premolar region. Both conventional radiographs and subtraction images were interpreted by 10 observers. The receiver-operating characteristic (ROC) technique was used to compare the two techniques. The diagnostic validity was higher for the subtraction technique, both for lesions confined to cancellous bone and for lesions including the cortical bone, than for the conventional technique. For bone defects confined to cancellous bone the diagnostic accuracy was lower than those reported from periapical bone lesions irrespective of whether subtraction or conventional radiography was used. We conclude that subtraction radiography improves the detectability of bone lesions, shallow ones in particular. Lesions in the interradicular bone are more difficult to detect than those in the periapical bone.

Alveolar Process↗
PubMed1992

[Technique for measuring the atheroma volume in men].

The evaluation of the impact of therapy on the evolution of atherosclerotic lesions or restenosis after angioplasty requires the use of techniques of vascular imaging. The reference invasive method is digital angiography although it does not provide data on the arterial wall thickness. This parameter can be approached however by intravascular ultrasound imaging, a technique which has a number of important practical limitations. Of the non-invasive techniques available, Doppler ultrasonography is the only one that can be used in clinical trials. Nuclear magnetic resonance imaging is the object of much research and is without doubt the technique of the future. The choice of model of atherosclerosis influences that of the imaging technique: cineangiography for coronary arteries, digital angiography or Doppler ultra sonography for lower limb arteries and Doppler ultrasonography for the carotid arteries. Interpretation of angiography is now performed quantitatively by videodensitometry. Interpretation of other techniques should be performed by a second independent observer and "blinded" with respect to the order in which the investigations were performed and to the treatment administered. The criteria of judgment may be qualitative (progression, stabilisation, regression) or quantitative, the latter having a number of advantages over the former. Of the quantitative criteria, the percentage stenosis, though widely used, does not fully answer the question posed, and neither does the diameter of the stenosis. The volume of the arterial lumen calculated from videodensitometric data would seem to be the best, by its sensitivity and additivity, current angiographic parameter.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography, Digital Subtraction↗
PubMed1992

Estimating the validity of radiographic measurements of marginal bone height changes around osseointegrated implants.

The accuracy of determining marginal bone height changes around osseointegrated implants depends on the validity of comparing serial films and the reliability of the measurements. X-ray beam orientation changes can alter the validity of serial films. A human dry mandible containing a Brånemark implant was irradiated +/- 12 degrees in the vertical plane at 1-degree intervals to the perpendicular to the long axis of the fixture. The thread width was recorded on both sides of each fixture image using a computer. Twenty-five randomized unclassified images were remeasured and the vertical angle of the x-ray beam was estimated from the previous measurements to test for validity of comparing images. The reliability of measurements with altered image magnification and penumbra were calculated. The reliability of 24 repeated thread width measurements was a SD of 0.01 mm. Of the 25 unknown beam angulations, 32 percent matched correctly, 20 percent +/- 1 degree, 16 percent +/- 2 degrees, or 68 percent < or = +/- 2 degrees. Alteration from a short to a long cone technique was estimated to produce magnification errors similar to the reliability SD of 0.01 mm. Similarly the penumbra varied from 0.057 mm to 0.032 mm with short to long cones using a 1.0-mm focal spot. With a 0.6-mm focal spot, the smallest penumbra of 0.19 mm was twice the measurement reliability. This method demonstrated x-ray beam angulation and validity for comparing serial films can be estimated for the extreme variations but not accurately for +9 to -6 degrees from a tangent to the fixture.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Bone Loss↗
PubMed1992

A method to evaluate and compare roentgenograms.

A simple and practical method is suggested to evaluate and compare roentgenograms concerning optical density and contrast. The method is specifically indicated for research in which a metallic stepwedge penetrometer and a photodensitometer are used. A PC computer may be optionally employed for the mathematical and statistical processing of the data.

Contrast Media↗
PubMed1992

Improved diagnosis with digital radiography.

In radiodiagnosis, much effort is spent in reducing the radiation dose and simultaneously improving the information obtained with radiographs. Computer technology has the potential to significantly impact radiography in medicine and in dentistry to achieve these goals. Advanced digital imaging techniques will be available for the general practitioner within the next decade. Storage and retrieval of images, contrast enhancement, and noise reduction are some examples of basic image manipulation tools. Subtraction radiography and image reconstruction will improve diagnosis and treatment planning. The clinical knowledge of dentists and radiologists will be incorporated into computer programs to perform more sophisticated tasks in the form of automated image analysis and computer-aided image interpretation.

Humans↗
PubMed1992

[Documentation of digital dacryocystography using video technique].

Digital dacryocystography is considered the optimal radiodiagnostic method in obstructions of the lacrimal pathways. The examination is carried out by a computer-controlled X-ray unit with a C-arc attached to an image-intensifying TV system. In this way the advantages of this technique and of modern video recording are linked. The bilateral filling process of the contrast medium is recorded and the findings simultaneously recorded on videotape. Consequently, pictures of the dynamic flow are retrievable at any time. This provides good diagnostic documentation and an outstanding basis for any scientific analysis.

Diagnosis, Differential↗
PubMed1992

Quantitative analysis of the coronary angiograms.

This was a two-step study performed to assess the validity of a computer system in the quantification of coronary arterial angiography (CAG). First, the in vitro study involved 10 aluminum tubes in different internal diameters but the same thickness which were pre-filled with 76% urograffin followed by cinefilm taking. Acquisition and digitization of the stop film was undertaken by a videocamera linking to a computer system. The internal diameters and mean gray levels of all tubes were measured to compare with the real diameters and areas. Second, the in vivo study calculated the percentage of stenosis by visual estimation, diameter measurement and gray level measurement by the computer system from 22 vessels in 13 coronary angiograms. The percentage of patency is the ratio of the diameter or gray level from stenotic region to that of normal region in the CAG. The calculated interobserver variability by visual estimation, diameter measurement and Mean gray level measurement were studied. Good correlation was found between measured diameters and true tube diameters (r = 0.99), and between gray level and tube areas (r = 0.94). The diameter measured by computer and the gray level had lower variability (4.0% and 5.7% respectively) than visual estimation (9.8%) did. Thus, the diameter and densitometric gray level measurements might have clinical implications to assess the coronary arterial stenosis from the coronary angiograms.

Aged↗
PubMed1992

[The value of digital luminescence radiography within the scope of traumatologic follow-up examinations].

At the present time we cannot unhesitatingly recommend the general use of digital luminescence radiography in traumatological follow-up examinations. Marked drawbacks of this method are, for example, sudden changes in contrast in the marginal areas of osteosynthesis material, occasional limitations in the detailed assessment of spongious structures and problems in respect of imaging geometry. By modifying the image processing parameters, increasing the image matrix and enlarging the format spectrum, however, these problems should be capable of being resolved in the future. Positive features, on the other hand, are even now the possibility of reducing the dosage to a marked degree in many traumatological follow-up examinations, especially in children and adolescents, and in case of conservatively treated fractures. In the long run we can foresee the routine use of digitalised examination methods on traumatology coupled with the possibility of storage in an image filing and communication system, although this is at present not yet feasible due to lack of requisite experience and the cost of the necessary equipment.

Computer Systems↗
PubMed1992

[Three-dimensional analysis of arteriography in human posterior circulation (preliminary report)].

In earlier articles it was suggested that there is a relation between vertigo and the posterior circulation. This study was designed to ascertain the course of the branches of the vertebral artery and the basilar artery, as well as the principal blood vessels of the vestibular nucleus by using radiographic three-dimensional observation. We studied 27 human brains (17 males, 10 females) fixed with the arterial embalming method at the Department of Anatomy of Kawasaki Medical School. The results were as follows: 1. Many variations in the course of the anterior inferior cerebellar artery and the posterior inferior cerebellar artery were observed, but the most frequent pattern, observed in 56% of our subjects, was the anterior inferior cerebellar arteries originating from the basilar artery and the posterior inferior cerebellar arteries from the vertebral artery. 2. Measurement of the inside diameter of both vertebral arteries showed the diameter of the left side to be thicker than that of the right side. 3. Perforating branches in the brain stem consisted of the pontine branches from the basilar artery and small branches from the anterior inferior cerebellar artery. Moreover, the transverse section showed a large number of them to originate from the ventral part of the brain stem.

Aged↗
PubMed1992

[Endoscopic visualization of luminal organ and great vessels with three dimensional CT scanner. A new trial using volumetric CT].

Thirty cases examined by three dimensions CT scanner (3DCT) were reported. The observation of inner view using 3DCT were performed in 12 large vessels with vascular disorder, 10 pulmonary bronchus with lung cancer and 8 common bile ducts involved obstructive disease. In order to visualize interface of the lumen, a new software which was devekioed by HITACHI MEDICO Inc. and us was brought in. In all cases but one the inner view of the luminal organ was clearly demonstrated as 3D images and it was possible to judge some changes of luminal interface involved by the diseases. The 3DCT endoscopic image might be useful as a new endoscopic technique without fiberscopy.

Aortography↗
PubMed1992

Computed radiography.

Explore the source record for details and available documents.

Radiographic Image Interpretation, Computer-Assist↗
PubMed1992

The reliability of computerized cephalometric soft tissue prediction following bimaxillary anterior subapical osteotomy.

The accuracy of predicting the results of orthodontic-surgical treatment following bimaxillary anterior subapical setback osteotomy was analyzed retrospectively. Comparisons of pretreatment prediction tracings of the lateral cephalograms with the 6-month postsurgical cephalograms of 38 patients showed that there was no statistically significant difference between the actual and predicted dentoalveolar setback in both arches. The computer-generated soft tissue predictions were generally accurate, with the exception of the horizontal position of the lower lip, which was underestimated, and, to a lesser extent, the vertical position of the upper lip, which was also underestimated. Computerized cephalometric prediction following bimaxillary anterior subapical osteotomy is sufficiently accurate to be of value to be used routinely in treatment planning for the horizontal upper lip prediction, but some modifications are advisable to obtain a more accurate horizontal lower lip prediction.

Adult↗
PubMed1992

Line drawing analyses of static cervical X ray used in chiropractic.

OBJECTIVE: This review article identifies the chiropractic techniques used to assess the structure of the cervical spine as seen on the static cervical radiograph. DATA SOURCES: On-line search of MEDLINE, key words, radiograph and X ray in combination with cervical spine (vertebrae); the Chiropractic Research Archives Collection (CRAC); indexes published in the Journal of Chiropractic Research; conference proceedings from Annual Biomechanics Conference of the Spine, FCER sponsored conferences and Annual Upper Cervical Spine Conference; references identified from bibliographies of pertinent articles; a telephone poll of radiography/technique instructors at chiropractic colleges. STUDY SELECTION: Techniques that quantitatively assess relative alignment of skeletal structures or distortion of the spinal column. DATA EXTRACTION: Techniques were grouped according to the structures analyzed and the views used. DATA SYNTHESIS: Variables and artifacts that limit the reliability or validity of static cervical X ray line drawing analysis were identified and the techniques assessed for their reported reliability and validity. CONCLUSIONS: Reliability studies exist showing that inter- and intraexaminer reliability are sufficient to measure lateral and rotational displacements of C1 to within +/- 1 degree. This amount of error allows objective analysis of upper cervical X rays to detect changes in the angular positional relationships of radiographic images on the order of those already seen clinically. Methods of cervical analysis that use relative angular measures of skeletal positioning are best able to control the effects of radiographic distortion. The accuracy of the analysis methods has not been ascertained to establish the extent to which angular measurement of vertebral relationships actually reflect three-dimensional movement. It is not known how much of the changes that are seen in pre/post-radiograph sets are due to positioning changes of the patient between radiographic procedure, and how much are due to actual changes of skeletal relationships brought about by adjustment.

Cervical Vertebrae↗
PubMed1992

[Evaluation of the kinetics of the left ventricular wall using the Cardio 200 computer].

The WALLMO program was used in comparing normal kinetic values of left ventricle wall with those obtained from control patients and literature sources. Authors concluded that, when based on the original data for RAO projection, the evaluation of regional LV wall contractility gives erroneous results in estimating whether a given section is normo- hypo- or hyperkinetic. Therefore, the set of normal kinetic values of LV motion has been formed for individual numbers of radials. This set may be used also at other working sites.

Adult↗
PubMed1992

[Conventional roentgen functional diagnosis--videodensitometry. 1. Densitometric and topometric measurements of roentgen video images: technique and method of measuring].

It is possible to measure movements in the human body with the help of X-ray television systems. A great number of different techniques has been published in the scientific literature. They all based on only two principles with qualitative differences in signal acquisition. The densitometric and topometric measurements are assessed and compared. Neither the densitometric nor the topometric principle seems to be superior. To support the experimental work the videoanalyser VIANA MP was developed on the Ilmenau Institute of Technology.

Computer Systems↗
PubMed1992

[Conventional roentgen functional diagnosis--videodensitometry. 2. Clinical imaging site for noninvasive diagnosis of organ motion].

By means of the described system it is possible to measure and as well analog as digital process the organ movement, needing a X-ray television system for flouroscopy and a videotape for continuously recording. Using the densitometric principle measurements of time and a quantitative form analysis of the curves are performed. After border recognition and using the topometric principle, the local organ motion can be evaluated. The levels of signal and noise in the measured curves are computed by a fourier transformation. In the field of functional cardiology the video signal is recorded and processed synchronously with the electrocardiogram.

Computer Systems↗
PubMed1992

An introduction to model-based imaging.

The purpose of this paper is to clarify the distinction between the recognition of form, i.e. pattern recognition, and the interpretation of visual scenes, i.e. image understanding. Pattern recognition is part of image understanding, but the latter also includes cognitive tasks such as learning and inference. The key to developing image-understanding systems is to concentrate on the representation and use of models. This paper is a brief outline of the components of a model-based image-understanding system. First, the notions of iconic, categorical and symbolic knowledge are described. Although they appear to be disparate, the common notion is that the image understanding is based on recognizing concepts and not recognizing form. Next, the notion of a concept is defined, followed by representation techniques and control strategies for using concepts. Last, an example is given of an image-understanding system that learns to recognize concepts such as radiographic projections of teeth in panoramic radiographs.

Expert Systems↗