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Biomedical subjects

A Van Steen

Publications and source records attributed to A Van Steen.

At least 19 recordsLinked to original sources
PubMed2006

Evaluation of the diagnostic value of a computed radiography system by comparison of digital hard copy images with screen-film mammography: results of a prospective clinical trial.

The purpose of the study was to determine prospectively the diagnostic value of a computed radiography (CR) system by comparing mammographic hard copy images with screen-film mammography (SFM). A series of 100 patients, who came for diagnostic investigation, underwent two-view SFM (Lorad M-IV Platinum) and digital mammography with a CR system (AGFA CR system). The images were obtained by double exposure, i.e. same view without removing compression of the corresponding breast. The CR images were processed with dedicated processing for mammography. Six radiologists read sets of SFM and CR images. The primary efficacy parameter was the overall diagnostic value. The secondary efficacy parameters were lesion conspicuity and lesion details (for masses and micro-calcifications), tissue visibility at chest wall and at skin line, axillary details, overall density and sharpness impression and the overall noise impression. These parameters were scored by a 7-point scoring system. "CR non-inferior to SFM" was concluded if the lower confidence interval bound exceeded 80%. The confidence interval for the overall diagnostic value was between 96.4% and 100%. Pooled analysis of the ten features for image quality comparison demonstrated for all but one feature (lesion details of the calcifications) CR non-inferiority to SFM.

Adult↗
PubMed2006

Image quality measurements and metrics in full field digital mammography: an overview.

This paper gives an overview of test procedures developed to assess the performance of full field digital mammography systems. We make a distinction between tests of the individual components of the imaging chain and global system tests. Most tests are not yet fully standardised. Where possible, we illustrate the test methodologies on a selenium flat-panel system.

Contrast Media↗
PubMed2006

Current challenges of full field digital mammography.

Full field digital mammography (FFDM) has advantages over screen-film mammography (SFM), but some important challenges remain. The first challenge is related to the specific characteristics of FFDM. It remains unclear, which shape and limiting values of the modulation transfer function have the most influence on the performance of a detector, such as the effect of the image display on the overall image quality and the effect of processing on cancer detection. In order to assess the image quality of FFDM, we have set up a scoring system. The second challenge is related to screening mammography: is the quality of an image the same when it is viewed on different monitors and with different processing algorithms? Is Computer Aided Diagnosis necessary in a screening environment? In FFDM, the effect of different detectors, processing and display possibilities on the image and on cancer detection are not clearly investigated.

Breast Neoplasms↗
PubMed2000

Review of MR mammography techniques.

Many of the new techniques of MRI have promising characteristics for the further improvement of sensitivity and specificity but there remains a large place for clinical trials to evaluate the practical value of the different new approaches. The authors review the general MRI rules that determine image quality and comment on the use-fullness of innovations in MR mammography.

Breast Diseases↗
PubMed1999

Confrontation of mammography systems in flanders with the European Guidelines for Quality Assurance in mammography screening. Analysis of initial results.

From May 1997 to April 98, 30 radiological centers made an agreement with the Leuvens Universitair Centrum voor Kankerpreventie (LUCK) for the work out of physical and technical quality control in mammography screening. A protocol was used based on the European Guidelines for Quality Assurance. The reports of all 30 acceptance tests were retrospectively reviewed. The following parts showed to be most critical: alignment of radiation field and film in the bucky, tube voltage precision, automatic exposure controller, average optical density of a standard exposure, dark room and its safe lights. The mean film gradient was in the majority of the centers higher than what is prescribed in the European document. This is acceptable and even desirable whenever daily quality control shows that the development system is sufficiently stable. Although it is difficult to compare the scores for the specific tests with results in other countries, there is evidence that the tendencies are very similar.

Absorptiometry, Photon↗
PubMed1997

Idiopathic granulomatous mastitis.

A case of idiopathic granulomatous mastitis mimicking breast carcinoma clinically and radiographically is reported with mammography, sonography and MR images.

Adult↗
PubMed1996

Crohn's disease.

Explore the source record for details and available documents.

Barium Sulfate↗
PubMed1995

[Mammographic symptomatology of malignant breast lesions].

Malignant breast images may include opacities (stellar--rounded with blurred margins), microcalcifications, opacities with microcalcifications, asymmetric fibroglandular tissue, or distortion of the mammographic pattern. Secondary signs may also be present, such as skin thickening, skin or nipple retraction, prominent vascularisation, axillary lymph nodes. The aim of this paper is to describe the different aspects and to make the differential diagnosis from benign tumors and normal tissue.

Breast↗
PubMed1995

[Galactography].

Spontaneous single duct discharge is the main indication for galactography. This abnormality has in most cases a benign aetiology (> 90%). With a meticulous technique and sufficient experience, the ducts can be cannulated in 95% of the cases. A nipple adenoma with a blood stained discharge is seldom to pass for cannulation. Because cytology of the nipple discharge is not always positive in case of intraductal proliferations, microdochectomy must be used to obtain the differential diagnosis. Galactography shows multiple normal duct variations, depending on age, surrounding tissue, and a possible history of lactation. Pathologic images can be seen in dystrophic breasts, solitary papillomas, (juvenile) papillomas or (intraductal) carcinomas. In addition to high frequency ultrasonography (> or = 10 MHz), which is able to visualise the retro-areolar and superficial ducts, galactography can give a more detailed and better overview of the pathology.

Adult↗
PubMed1995

[The history of gallbladder and bile duct diagnosis].

In the first period (1896-1910), investigation was made through plain abdominal film with description and differential diagnosis of the different calcifications in the right hypochondrium. Second period (1911-1924): indirect signs of liver and gallbladder pathology were described. Via pneumoperitoneum and gastro-intestinal opacification the pathology in the right hypochondrium was delineated and interpreted. Third period (1924 until now): due to the development of contrast agents for the gallbladder and biliary tree, these organs could be directly visualized either by intravenous injection, or by peroral administration; sometimes direct injection of contrast in the bile ducts was used.

Cholangiography↗
PubMed1993

Breast neoplasm.

Explore the source record for details and available documents.

Adult↗