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S Diederich

Publications and source records attributed to S Diederich.

104 records · Page 6Linked to original sources
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↗
PubMed1991

[Diagnostic imaging of the salivary glands in children and adolescents].

In children and adolescents, imaging of the salivary glands is a valuable supplement to clinical examination in various diseases. The choice of the most appropriate radiological technique depends on patient compliance, the necessity of avoiding radiation exposure as far as possible, and the tentative diagnosis made on the basis of the clinical examination. Ultrasonography (US) is the method of choice for the detection of both acute inflammatory disease and masses in the salivary gland and the adjacent tissue. US can also be implemented as a screening method for calculi, though sialography is superior for this purpose. Sialography is the only technique that allows diagnosis and evaluation of the degree of chronic inflammation. Computed tomography and magnetic resonance imaging are required for more deeply located neoplasms of the parotid region.

Adolescent↗
PubMed1991

[Diagnostic validity of imaging methods in the detection and observation of the progress of cases of invasive aspergillosis of the blood vessels of the lung].

Chest radiographs and thoracic computed tomograms (CT) of 21 patients with oncologic disease and vasoinvasive pulmonary aspergillosis (PA) were assessed and compared. CT findings were interpreted by comparison with histologic lung specimens of 28 lethal cases of PA. The analysis showed that in the early stages of infection findings suggestive of PA were only found in 29% of cases (n = 6) on conventional radiographs, whilst CT suggested the presence of PA in all cases (n = 21). In advanced stages, conventional radiographs suggested the presence of PA in 38% of cases (n = 8), which was not significantly different from that value for early disease. The comparison of CT with histopathologic findings allows their objective interpretation; such studies provide an improvement in both detection rate and characterization of CT changes in PA.

Adolescent↗
PubMed1991

[Radiologic findings following supraglottic and total laryngectomy].

The treatment of carcinoma of the larynx has recently been greatly improved with the development of supraglottic and total laryngectomy. This has also led to a high five year survival rate. The normal postoperative radiological appearances are presented together with the spectrum of relevant radiological investigations and their indications. The most frequently seen postoperative complications and findings in patients with dysphagia are described with special reference to pharyngograms and cineradiography. The morphology of the vibrating segment after laryngectomy in patients who do not develop effective alaryngeal speech is demonstrated.

Cineradiography↗
PubMed1991

[Parathyroid sonography in long-term dialysis].

In a prospective study the prevalence of sonographically enlarged parathyroid glands in patients on maintenance hemodialysis was investigated and correlated with clinical and laboratory findings of secondary hyperparathyroidism. We examined 97 unselected patients with a 5 MHz probe. In 34% (33/97) a total of 69 parathyroid glands were detected with a statistically significant correlation between the period of dialysis and the incidence of parathyroid enlargement; 47.8% of the glands were hypoechoic, 34.8% moderately echogenic and 17.3% gave echoes similar to the normal thyroid parenchyma. A correlation was found between the finding of enlarged parathyroid glands and blood levels of calcium and alkaline phosphatase. Parathyroid enlargement was found sonographically before, or in the absence of clinical and laboratory findings of secondary hyperparathyroidism. Sonography is therefore a useful technique for early diagnosis of hyperparathyroidism in patients on maintenance dialysis.

Adult↗
PubMed1990

[The diagnosis of deep venous thrombosis of the lower extremities using high-resolution real-time and CW-Doppler sonography. Accuracy and limitations].

The combination of high-resolution real time and continuous wave (CW) Doppler sonography is particularly valuable for the detection of venous thrombosis in the lower limbs. A total of 235 venous sonograms were prospectively compared with phlebography (gold standard) and indicated a sensitivity and specificity of 93%-100% and 96%-99%, respectively, depending on the thrombosis site. The positive and negative predictive values ranged between 90% and 97% and 97% and 100%, respectively. The value of real-time venous sonography, which basically entails assessing venous compressibility for the exclusion of thrombosis, is limited in the presence of small non-occlusive thrombi by the elasticity of the surrounding anatomic structures and the sonographic visibility of the veins. It is also evident that partial thrombosis in readily visualized veins (e.g., the inguinal region) is more obvious with sonography than phlebography. In addition, the proximal end of acute, extensive thrombus with poor collateral circulation is better visualized by sonography.

Adolescent↗
PubMed1990

[Thoracic sarcoidosis].

Sarcoidosis is essentially a granulomatous disease of unknown etiology. The pathogenesis is assumed to consist in an abnormal immune reaction to a still unidentified antigen. The commonest manifestations of sarcoidosis are mediastinal and hilar lymphadenopathy and pulmonary infiltrates. The complex variety of clinical presentations of sarcoidosis means that the differential diagnosis has to include a wide range of entities. The clinical and radiological features of thoracic sarcoidosis are described, and the spectrum of relevant investigations is discussed. With respect to radiological diagnosis, computed tomography, with its higher sensitivity than other techniques, is of particular value for the precise determination of the morphological correlate of pulmonary and nodal changes and their functional relevance.

Diagnosis, Differential↗
PubMed1987

[Sialographic and sonographic diagnosis of salivary gland diseases].

The diagnostic value of sialography and ultrasonography was studied retrospectively in 130 patients with diseases of the salivary gland. In the diagnosis of tumours (sensitivity: 97.5% vs 52.5%), acute inflammatory diseases (sensitivity: 70% vs 40%) and abscesses (sensitivity: 100% vs 25%) ultrasound was more accurate than sialography. Even in the diagnosis of calculi, ultrasound gave good results (sensitivity: 71.4%) and should be performed before the more invasive sialography technique. In chronic inflammatory diseases, sialography continues to be the technique of choice.

Abscess↗
PubMedDate not supplied

Metabolism of synthetic corticosteroids by 11 beta-hydroxysteroid-dehydrogenases in man.

The presence of an 11 beta-hydroxyl group is essential for the anti-inflammatory and immunosuppressive effects of glucocorticoids. Interconversion of the 11 beta-hydroxyl into the corresponding 11 beta-keto group and vice versa by 11 beta-hydroxysteroid-dehydrogenase (11 beta-HSD) may thus play a pivotal role in the efficacy of these steroids. Therefore, we have compared the metabolism of the endogenous glucocorticoid cortisol (F) with that of synthetic 9 alpha-fluorinated steroids by 11 beta-HSDs in humans in vivo and in vitro. Whereas 30% of the free steroids in urine after oral administration of 5 mg of F is F itself and 70% the inactive keto-product cortisone (E), the urinary excretion of an identical dose of oral 9 alpha-fluorocortisol (9 alpha FF) is 90% 9 alpha FF and 10% inactive 9 alpha-fluorocortisone (9 alpha FE). Kidney slices similarly convert F much faster to E than 9 alpha FF to 9 alpha FE; conversely, renal 11 beta-reduction of 9 alpha FE to 9 alpha FF is much more effective than that of E to F. Kinetic analyses in human kidney cortex microsomes prove that the preference of fluorinated steroids for reduction in human kidney slices is catalyzed by 11 beta-HSD type II: the NADH-dependent conversion of 11-dehydro-dexamethasone (DH-D), another fluorinated steroid, to dexamethasone (D) is very effective (high affinity, high Vmax), whereas reduction of E to F is very slow. In human liver microsomes (11 beta-HSD type I), nonfluorinated (E) and fluorinated 11-dehydrosteroids (DH-D) are both reduced to their corresponding active 11-hydroxyderivatives but with a Michaelis-Menten constant about 20-fold higher than for kidney microsomes (11 beta-HSD-II). Our results suggest that the decreased renal 11 beta-oxidation of 9 alpha-fluorinated steroids may offer pharmacokinetic advantages for renal immunosuppression. Furthermore, administration of fluorinated 11-dehydrosteroids is a new and exciting idea in glucocorticoid therapy in that small amounts of oral DH-D may pass the liver largely unmetabolized (11 beta-HSD-I has low affinity for such steroids) and may then be activated to D by high-affinity 11 beta-HSD-II, thus allowing selective immunosuppression in organs expressing 11 beta-HSD-II (kidney and colon).

Adrenal Cortex Hormones↗