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Biomedical subjects

P E Peters

Publications and source records attributed to P E Peters.

At least 19 recordsLinked to original sources
PubMed1992

[The morphological analysis of the vertebral spongiosa in quantitative CT].

The diagnostic ranking of trabecular morphology for the evaluation of osteoporosis in quantitative CT (QCT) is presented. 5 patterns of cancellous bone correlating with trabecular density may be discerned. However, these patterns may indicate osteoporotic changes in particular cases only, by confluent rarefactions if the density is still within the normal range. There is neither a predictive value for the degree of spontaneous or therapy-induced bone loss, nor for therapy response. The trabecular appearances remain unchanged in short term even under strong quantitative changes and are therefore of no value for follow-up.

Adrenal Cortex Hormones↗
PubMed1992

[The MR tomography of hemophilic osteoarthropathy with special reference to the synovial and chondrogenic changes].

52 knee and ankle joints of hemophiliacs were examined by MRI using FLASH and FISP-3-D sequences; and the degree of synovial hypertrophy and of cartilage destruction were assessed. Findings of synovial hypertrophy varied between thin membranes and tumorous tissue destroying the joint cartilage. Degree of cartilage destruction varied between focal signal decrease and total loss. In spite of recurrent joint bleedings no synovial or cartilaginous changes were seen in 31% and 29% of joints, respectively. Changes were more frequently seen and degree was more marked in the ankle than in the knee joints. With the exception of cysts, osseous destruction was more obvious with radiographs. MRI is suitable for the investigation of joints of hemophiliacs showing no osseous destruction.

Adolescent↗
PubMed1992

[Dynamic MR tomography in the diagnosis of inflammatory and tumorous space-occupying lesions of the musculoskeletal system].

In 216 inflammatory and tumorous lesions of bone and soft tissue, dynamic Gd-DTPA enhanced MR imaging was performed. For that purpose, 12 FLASH sequences (TR = 40 ms/TE = 10 ms/NSA = 2/flip angle = 90 degrees) were acquired within 4 minutes; and Gd-DTPA bolus injection was administered following the first sequence. Slopes from the signal intensity curves were calculated. Estimated slopes allowed an assessment of the malignant potential of a lesion with an accuracy of 88%. Further more, a reliable differentiation between vital and necrotic tissue and between tumour and peritumoral edema was reliably possible. With this technique, response of malignant tumours to preoperative chemotherapy was correctly predicted in 83% of the cases. No differentiation of inflammatory from tumorous lesions was possible.

Bone Neoplasms↗
PubMed1992

Comparison between high-field-strength MR imaging and CT for screening of hepatic metastases: a receiver operating characteristic analysis.

The diagnostic performance of high-field-strength magnetic resonance (MR) imaging (1.5 T) for detection of liver metastases was compared with that of computed tomography (CT). All patients (n = 52) underwent preoperative screening for metastases by means of MR imaging with T1-weighted, proton-density-weighted, and T2-weighted pulse sequences and CT scanning with unenhanced, incremental dynamic bolus-enhanced, and delayed contrast medium-enhanced techniques. Diagnostic performance was evaluated by means of receiver operating characteristic analysis in which 800 images (400 with and 400 without lesions) and five readers (4,000 observations) were used; images were obtained from patients (n = 39) in whom the same anatomic levels were available for all MR imaging and CT studies. Direct comparison between the best MR imaging technique (T2-weighted spin-echo imaging [repetition time, 2,000 msec; echo time, 70 msec]) and the best CT technique (incremental dynamic bolus CT) showed a strong trend of superiority of T2-weighted MR imaging over incremental dynamic bolus CT. No highly statistically significant difference (P greater than or equal to .01), however, was found between these two techniques.

Esophageal Neoplasms↗
PubMed1992

Differentiation of benign from malignant superficial lymphadenopathy: the role of high-resolution US.

Ultrasonography has proved a valuable tool for the detection of enlarged lymph nodes; however, differentiation between benign and malignant nodal disease remains a problem. High-frequency probes with improved spatial and contrast resolution display superficial nodes to advantage and also show the internal structure of the nodes. Ninety-four superficial nodes in patients with suspected nodal disease were examined by using 7.5-MHz probes to evaluate longitudinal-transverse diameter ratio (L/T), the central hilus, cortical widening, and size. Histologic diagnosis was obtained after sonographic examination in 73 nodes (five reactive nodes, 35 primary nodal malignancies, and 33 nodal metastases). The remaining 21 nodes regressed after either antibiotic or no therapy. Marked differences were observed among the proportions of benign and malignant nodes in terms of L/T, hilus, and cortex; the latter two structures, however, must be interpreted together. Eccentric cortical widening was seen in only malignant nodes. The distribution of nodal size was not significantly (P greater than .1) different for benign and malignant nodes. No differences were observed between primary and secondary nodal malignancies. The sonographic criteria evaluated in this study assist in the differentiation of benign from malignant superficial lymph nodes.

Adult↗
PubMed1992

The distinction between benign and malignant liver tumors on sonography: value of a hypoechoic halo.

OBJECTIVE: The purpose of this study was to determine the diagnostic value of the sonographic halo sign (defined as any hypoechoic rim in the periphery of a lesion) in distinguishing between benign and malignant isoechoic and hyperechoic liver lesions on sonography. MATERIALS AND METHODS: Sonograms of the liver in 50 patients with proved benign liver tumors and in 50 patients with proved malignant liver tumors (seven primary liver neoplasms, 43 metastases) selected during a 13-month period were retrospectively analyzed by four radiologists who had no knowledge of the patients' clinical findings or the final diagnoses. Only a single sonogram was studied in each case. The presence or absence of a hypoechoic halo on the sonogram was the only criterion for distinguishing malignant from benign hepatic lesions. RESULTS: For 95 of 100 hepatic lesions, the four radiologists were almost (three vs one) or completely (four vs zero) in agreement about the presence or absence of a hypoechoic halo. In the five cases where there were conflicting decisions (two vs two), a final decision (four vs zero) was achieved by reviewing the entire series of sonographic images. A halo could be detected in 44 malignant tumors (88%) and in only seven benign tumors (14%) (sensitivity, 88%; specificity, 86%; positive and negative predictive values, 86% and 88%, respectively). The sonographic halo sign was particularly helpful in distinguishing hemangiomas (n = 29) from metastases (n = 43) (positive and negative predictive values, 95% and 87%, respectively). CONCLUSION: The results of this study suggest that the halo sign on sonograms is useful to distinguish benign from malignant isoechoic or hyperechoic tumors.

Adult↗
PubMed1992

Pathologic explanation for hypoechoic halo seen on sonograms of malignant liver tumors: an in vitro correlative study.

OBJECTIVE: The purpose of this study was to evaluate the morphologic substrate of the hypoechoic halo seen on sonograms of malignant liver tumors. MATERIALS AND METHODS: We used sonograms and pathologic examinations to evaluate 17 cadaveric livers with macroscopic tumors (three primary liver tumors, 14 metastases). During sonography (3.5 and 5.0 MHz), a representative section plane was marked, and the same section was examined histologically. Emphasis was placed on the architecture of the tumor and the morphology of the periphery of the tumor that could account for the hypoechoic halo seen on sonograms. RESULTS: In 13 of 17 hepatic tumors, a hypoechoic halo was detected on sonograms. Histopathologic examination showed an intratumoral rim consisting of proliferating tumor cells in 12 cases and an extratumoral rim of compressed liver parenchyma in all 13 cases. A detailed comparison of sonographic and histopathologic findings showed that the hypoechoic halo corresponded to a greater concentration of tumor cells and areas of less marked fibrosis and necrosis in the periphery of the tumors. This occurred in 11 cases. In one case, histologic studies showed that the hypoechoic rim was caused by compressed liver parenchyma. In another case, the hypoechoic halo was caused by intratumoral (cellular peripheral zone of tumor) and extratumoral (compressed liver parenchyma) components. All four tumors without a halo at sonography were uniform histologically. CONCLUSION: The sonographic halo seen on sonograms of malignant liver tumors seems to be caused predominantly by a zone of proliferating tumor in the periphery of the lesion.

Adenocarcinoma↗
PubMed1992

[Legionnaires' disease in intensive care patients. Results of plain film thoracic radiography].

We reviewed the chest radiographs and clinical data of 30 patients in an intensive care unit with legionellosis diagnosed by significant serological findings (n = 18), microscopic demonstration of the organism in the transtracheal aspirate (n = 5) or both (n = 7) and investigated the correlation between the identification of Legionella and signs of pulmonary infection. In 13 patients legionnaires' disease was diagnosed with a high degree of confidence. Typical radiographic findings included distal air space disease, which initially appeared to be unilateral, progressing towards bilateral infiltrates. Patchy infiltration at the onset of disease was followed by consolidation. Small pleural effusions were common, while no abscess formation was observed. Characteristically, infiltration persisted for weeks even with clinical convalescence. These radiological findings correspond well with observations in otherwise healthy patients with legionnaire's disease. In 10 patients the etiology of pulmonary infiltrates could not be identified. Seven patients did not develop radiological or clinical signs of pneumonia; therefore, the serological/microscopic detection of Legionella was not interpreted as legionnaires' disease. According to the results of our investigation the diagnosis of legionnaires' disease requires radiological findings in addition to laboratory data.

Adolescent↗
PubMed1992

[An economic comparison between digital luminescence radiography and conventional film processing in intensive care medicine].

The costs of a conventional film-screen radiography daylight-system and storage-phosphor computed radiography (Fuji AC-1) are compared. In 1990, 3841 radiologic procedures (mostly portable chest X-rays) were performed in 3474 patients of a surgical intensive care unit. With conventional film-screen radiography 6.8% retakes were necessary for diagnostic or technical reasons. Comparing the fixed and variable costs of both systems conventional film-screen radiography was more economic under the given conditions of the test. It is concluded that computed radiography in intensive care patients has definite advantages in terms of image quality and reproducibility, however, in order to compete successfully in the economic turf CR has to be implemented in a picture archiving and communication system (PACS).

Costs and Cost Analysis↗
PubMed1992

[Magnetic resonance tomography of soft tissue tumors].

Soft tissue tumors are relatively often seen on MR tomography, although they make up a fairly small proportion of malignant lesions. To date, most soft tissue tumors have been investigated by MRI because of its unique soft tissue contrasts and its flexibility in slice orientation. But is MRI really adequate for staging and defining soft tissue tumors, or what role does it have pre-therapeutic work-up? Most malignant soft tissue tumors give rise to somewhat similar MRI findings and may not be sufficiently well characterized. On the other hand, some benign lesions can be clearly identified and staged. The goal of this paper is a critical discussion of the ability of MRI to define a lesion's degree of malignancy, to evaluate diagnostic criteria, and to describe requirements in the set-up of the investigation.

Humans↗
PubMed1992

[Status and development of new clinical contrast media for MR diagnosis of liver diseases].

MR contrast agents are developed for pharmaceutical manipulation of tissue signal intensities. Today it is widely recognized that MR contrast agents will play an increasingly important role in MR imaging of the liver. Contrast-enhanced MR-imaging allows to obtain simultaneously dynamic physiologic information and high anatomic detail. Up to now three major classes of MR contrast agents are available for clinical MR-imaging of the liver. These include paramagnetic perfusion agents, hepatobiliary agents, and super-paramagnetic RES-specific iron oxide particles. A fourth class of contrast agents now in use for animal experiments includes ultra-small super-paramagnetic particles which can be targeted to extra-reticuloendothelial structures such as asialoglycoprotein receptors of hepatocytes. In this article, we review recent advances in the development of MR contrast media and the clinical status of contrast-enhanced MR imaging of the liver.

Acetates↗
PubMed1992

[Hemangioma of the left ventricle].

The authors describe the case of a histologically proven hemangioma in the left coronary artery of the left ventricle of a 24-year-old woman. The results of the different medical imaging methods applied are described and the treatment of cardiac angiomas is discussed.

Adult↗
PubMed1991

Comparison of technetium 99m polyclonal human immunoglobulin and technetium 99m monoclonal antibodies for imaging chronic osteomyelitis. First clinical results.

The accuracy of technetium-99m human immunoglobulin (HIG) for the detection of chronic osteomyelitis (OM) was compared with white blood cell scintigraphy using 99mTc-labelled monoclonal mouse antibodies (MAB). Seventeen patients suspected of having OM in 20 lesions went through three-phase skeletal scintigraphy, HIG scintigraphy and MAB scintigraphy. The final diagnosis was established by open surgery, histology and bacteriology. Chronic OM was proved in 14/20 lesions. Six of these 14 infections were located in peripheral areas without active bone marrow and 8/14 in central areas with active bone marrow. In peripheral OM, 5/6 with HIG and 6/6 with MAB were true positives. In the central skeleton all 8/8 infections appeared as cold lesions in the MAB study, which were defined as being false negative due to their non-specificity. Using HIG, 5/8 central infections were determined to be truly positive by showing photon-rich lesions. These 5 lesions were located in the hip region and in the pelvis, whereas 3 lesions of the spine were missed. There were no false-positive results in either studies. In conclusion, MAB was superior to HIG in peripheral OM concerning sensitivity, anatomical landmarks and differentiation of soft tissue versus bone infection. In central OM MAB detected all lesions accurately, but no differential diagnosis was possible due to the non-specificity of photon-low areas. In this respect HIG seems to be more specific due to the increased accumulation even in central infection sites.

Adult↗
PubMed1991

[The place of magnetic resonance tomography in the diagnosis of diseases of the shoulder joint].

In a prospective study 43 patients with shoulder pain were examined by sonography and MRI. The findings were controlled by plain radiography, arthrography, and CT arthrography. Joint effusions and humeral head defects were equally identified by MR and sonography. In the diagnosis of labrum lesions, rotator cuff lesions, subacromial spurs, and synovial inflammatory disease sonography was not as accurate as MR. A special MR scoring system improved the diagnosis of an impingement syndrome.

Adult↗