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Biomedical subjects

D Hahn

Publications and source records attributed to D Hahn.

At least 73 records · Page 4Linked to original sources
PubMed2000

Computed tomography after lymphangiography in the diagnosis of intestinal lymphangiectasia with protein-losing enteropathy in Noonan's syndrome.

Noonan's syndrome is a rare congenital disorder that may be associated with abnormalities in the lymphatic drainage. In this case of a 21-year-old man CT after bipedal lymphangiography confirmed the diagnosis of intestinal lymphangiectasy causing protein-losing enteropathy in Noonan's syndrome by showing contrast-enhanced abnormal lymphatic vessels in the mesentery and the intestinal wall. Because of the benefit of diet in case of intestinal involvement, we recommend a thorough documentation of the lymphatic drainage with lymphangiography followed by CT, if clinical signs of lymphatic dysplasia, such as pleural effusions, lymphedema, or hypoproteinemia are present.

Adult↗
PubMed2000

Technical advances in ultrasound and MR imaging of carpal tunnel syndrome.

The aim of this study was to compare the latest ultrasound-array technology to a conventional "high-resolution" transducer, modified MRI technique, and nerve conduction studies (NCS), in the diagnosis of carpal tunnel syndrome (CTS). In 19 normal wrists and 15 wrists with CTS, US with two different transducers was performed: a conventional linear-array transducer (LA) and a newly developed Multi-D linear-array transducer (MDA) were used. The US images were evaluated determining the swelling and the flattening ratios of the median nerve and correlated to respective findings in MRI (1.5 T) and to NCS. The NCS confirmed CTS in all 15 wrists. Measures of median nerve compression (swelling and flattening ratios) were significantly different in patients with CTS and controls (p < 0.01) with both types of US transducers and MRI. The MDA yielded higher correlation to MRI than the LA. Using critical values of 1.3 for the swelling and 3.4 for the flattening ratio, MRI, and US with the MDA yielded a sensitivity of 100% each. Modern imaging modalities allow for an exact diagnosis of CTS even in cases with only slight median nerve pathology.

Adult↗
PubMed2000

Age- and gender-specific differences in left and right ventricular cardiac function and mass determined by cine magnetic resonance imaging.

We examined possible age- and gender-specific differences in the function and mass of left (LV) and right (RV) ventricles in 36 healthy volunteers using cine gradient-recalled echo magnetic resonance imaging. Subjects were divided into four groups (nine men and nine women in each): men aged under 45 years (32 +/- 7), women aged under 45 (27 +/- 6), men aged over 45 (59 +/- 8), and women aged over 45 (57 +/- 9). Functional analysis of cardiac volume and mass and of LV wall motion was performed by manual segmentation of the endocardial and epicardial borders of the end-diastolic and end-systolic frame; both absolute and normalized (per square meter body surface area) values were evaluated. With age there was a significant decrease in both absolute and normalized LV and RV chamber volumes (EDV, ESV), while LV and RV masses remained unchanged. Gender-specific differences were found in cardiac mass and volume (for men and women, respectively: LV mass, 155 +/- 18 and 110 +/- 16 g; LV EDV, 118 +/- 27 and 96 +/- 21 ml; LV ESV, 40 +/- 13 and 29 +/- 9 ml; RV mass, 52 +/- 10 and 39 +/- 5 g; RV EDV, 131 +/- 28 and 100 +/- 23 ml; RV ESV, 53 +/- 17 and 33 +/- 15 ml). Normalization to body surface area eliminated differences in LV volumes but not those in LV mass, RV mass, or RV function. Functional parameters such as cardiac output and LV ejection fraction showed nonsignificant or only slight differences and were thus largely independent of age and gender. Intra- and interobserver variability ranged between 1.4% and 5.9% for all parameters. Cine magnetic resonance imaging thus shows age- and gender-specific differences in cardiac function, and therefore the evaluation of cardiac function in patients should consider age- and gender-matched normative values.

Adult↗
PubMed2000

Asymptomatic aneurysm of the proximal right subclavian artery: a rare ultrasound diagnosis.

True aneurysms of otherwise normal subclavian arteries are uncommon peripheral vascular anomalies. Most patients with subclavian artery aneurysms are symptomatic by presenting neurologic signs. We report a young woman who had an asymptomatic true aneurysm of the right subclavian artery assumed to be of congenital origin. This case is unique in that the aneurysm was in the extremely rare anatomic location of the right supraclavicular fossa between the origins of the right subclavian artery and the vertebral artery. Aneurysms of the right subclavian artery may represent a potential pitfall in conventional gray-scale ultrasound of the neck particularly the supraclavicular fossa. Differential diagnosis includes cervical cyst, pharyngo-esophageal diverticulum, vascular anomalies, struma, enlarged lymph node, as well benign or malignant neoplasms. Color duplex ultrasound should be performed as the method of choice for further analysis of suspected aneurysms. In this report the role of B-mode ultrasound and color duplex ultrasound is discussed in relation to digital subtraction- and MR angiography in confirmation of the diagnosis.

Adult↗
PubMed2000

Pathological angioarchitecture in lymph nodes: underlying histopathologic findings.

Pathologic changes of the intranodal angioarchitecture, as displayed by colour Doppler sonography, were used in recent studies to predict malignant infiltration of superficial lymph nodes. We searched for the underlying histopathologic findings in a prospective study including 100 lymph nodes in 86 patients. In the histopathologic specimens, we evaluated tumour infiltration, distribution of intranodal vessels, hilar structures, thickness of the capsule and tissue alterations (necrosis, sclerosis, lipo-/fibromatosis). Using the only prospectively tested classification, a pathologic angioarchitecture was described as displacement, aberrant course, avascular foci or subcapsular vessels. Testing these four criteria by multivariate regression analysis, the most important correlations were found between the following pairs of sonographic and histopathologic findings: displacement with perinodal tumour spread, aberrant vessels with intranodal sclerosis, avascular foci with intranodal necroses and subcapsular vessels with intranodal necroses. In conclusion, the criteria describing a pathologic angioarchitecture correlate with histopathologic findings that are frequently seen in malignant lymph nodes.

Adolescent↗
PubMed2000

Hepatic artery embolization: factors predisposing to postembolization pain and nausea.

PURPOSE: Analysis of preprocedural factors that may be helpful in predicting the severity of pain and nausea after hepatic arterial embolization (HAE) for liver neoplasms. MATERIALS AND METHODS: During a 2-year period, 62 patients (33 men, 29 women) underwent 130 palliative lobar HAEs for unresectable liver neoplasms. The hepatic lobe was embolized with 150-250-microm polyvinyl alcohol particulates with or without lipiodol and/or chemotherapeutic agents. Postembolization pain was rated at rest and during movement with use of an 11-point verbal pain scale, and postembolization nausea was assessed with use of a four-point verbal scale, each at two separate time periods. Daily morphine use was also recorded. Primary analysis was made using the first embolization procedure. One-way analysis of variance and Spearman correlation coefficients were used to identify associated predictors. Plots of the outcomes versus the pre-embolization liver function tests and sensitivities and specificities were used to identify the strength of the associations for prediction purposes. A secondary analysis was performed in patients who underwent multiple embolizations. RESULTS: No strong categorical predictors were found from the ANOVA on the severity of postembolization pain or nausea. There were significant (P < .05) associations between the pre-embolization liver function tests and the pain outcomes only. However, while these laboratory values demonstrate strong associations with resultant pain, they are not strong predictors of pain and morphine requirements for any individual patient. The morphine requirements were highly associated (P < .0001) with the pain scores at rest and with movement. The authors did not find significant differences on any of the pain outcomes or morphine requirements between the first and second embolizations. CONCLUSION: Laboratory values and patient age are not predictors for the severity of postembolization pain and nausea. Postembolization pain is a significant complication and poses a continuing challenge to the physician with regards to patient management.

Adult↗
PubMed2000

Erdheim-Chester disease: evidence for a disease entity different from Langerhans cell histiocytosis? Three cases with detailed radiological and immunohistochemical analysis.

Erdheim-Chester (EC) disease is a rare pathological entity with a highly specific and characteristic pattern of radiographic bone changes. Histologically it resembles Langerhans cell histiocytosis (LCH), and it is still a matter of discussion whether EC disease is a distinct entity or a type of LCH. In this study, 3 cases of Erdheim-Chester disease were followed up over years and examined in detail both radiologically and immunohistochemically. All 3 cases showed the pathognomonic skeletal features for EC disease as well as an identical immunohistochemical phenotype quite different from LCH. Macrophages and Touton cells reacted strongly positive with the histiocytic marker CD 68, whereas staining with S100 and CD1a, markers for Langerhans cells, were negative. Both the immunohistochemical phenotype and the bone changes were clearly distinct from LCH.

Antigens, CD↗
PubMed2000

[Arthrography, ultrasound and MRI in rotator cuff lesions: a comparison of methods in partial lesions and small complete ruptures].

PURPOSE: To evaluate the accuracy of arthrography, ultrasound and MR imaging in rotator cuff disease. METHODS: 40 patients suffering from subacromial impingement syndrome for at least three months and who were selected for surgery, underwent ultrasound, double-contrast arthrography and MR imaging. Patient preselection focused on partial and small complete tears. RESULTS: 13/26 surgically confirmed tears were partial tears (articular surface: 10, bursal surface: 2, intra-substance tearing: 1). Arthrography, ultrasound and MR imaging yield a sensitivity for complete tears of 91%, 69% and 92% with a specificity of 100%, 93% and 93%. For partial tears sensitivity was 50%, 69% and 69% with a specificity of 100%, 79% and 86%. Concerning evaluation of localisation, extent and correct classification ultrasound was correct in 17/26 cases, MR in 21/26 cases. CONCLUSION: Arthrography is not helpful in detecting partial tears. Ultrasound and MR imaging yield comparable accuracy. MR imaging has advantages concerning better evaluation of extent, location and classification as well as for the detection of associated pathologies.

Arthrography↗
PubMed2000

[Comparison of contrast harmonic imaging in B-mode with stimulated acoustic emission, conventional B-mode US and spiral CT in the detection of focal liver lesions].

PURPOSE: Comparison between contrast harmonic imaging (CHI) in B-mode with stimulated acoustic emission (SAE), conventional B-mode US, and spiral CT in the detection of focal liver lesions. METHODS: In this pilot study 26 patients with liver lesions diagnosed by B-mode US and contrast-enhanced spiral-CT were additionally examined with CHI in B-mode. Each examination started with a bolus injection of 4 g of the US contrast agent Levovist (300 mg/ml) after a delay of at least 5 minutes to ensure liver-specific phase. All examinations were documented on video tapes and analysed by two radiologists. RESULTS: 81 liver lesions were diagnosed with both US examinations and spiral CT. B-mode US detected 66 lesions, CHI with SAE 72 lesions, and spiral CT 73 lesions. Compared to spiral CT 8 lesions in 3 patients could be depicted additionally with both US methods. Metastases and HCC present in CHI with SAE as not-enhancing signal contrast agent areas. Delineation of haemangiomas and FNH was often worse compared to the native examinations. CONCLUSION: The new US method CHI with SAE depicted more lesions than conventional B-mode US and is in some cases superior to spiral CT.

Adult↗
PubMed2000

[(23)sodium MRI for infarct imaging of the human heart].

PURPOSE: Sodium is elevated in acute/subacute myocardial infarction due to three distinct mechanisms: Breakdown of ion homeostasis with accumulation of intracellular sodium, extracellular edema formation and, during scar formation, increase of extracellular vs. intracellular space as cardiomyocytes are replaced by connective tissue. 23Na MRI has previously been shown to have the potential to demonstrate myocardial infarction in an animal model. Aim of this study was, therefore, to demonstrate myocardial infarction with the use of 23Na-MRI in patients. MATERIAL AND METHODS: 10 patients were examined 14 +/- 7 days after first myocardial infarction using a 23Na surface coil at 1.5 T. Double angulated short axis images of the entire heart were imaged using an ECG-triggered 3d-FLASH-sequence (FOV, 450 mm; matrix, 64 x 128; spatial resolution, 3.5 x 7 mm2; slice thickness, 16 mm; 32 acquisitions). Areas of elevated sodium signal intensity were correlated with infarct-related wall motion abnormalities imaged by Cine MRI in breathhold-technique. RESULTS: All patients showed an area of elevated sodium signal intensity that correlated well with the clinically determined localization of myocardial infarction as well as with regional wall motion abnormalities detected by Cine MRI. CONCLUSIONS: Elevated 23Na MR image signal intensity demonstrates subacute myocardial infarction in patients.

Aged↗
PubMed2000

[New possibilities in the diagnosis and documentation using 3D power doppler ultrasound with carcinoma of the floor of the mouth as illustration].

AIM: To evaluate a novel 3D power Doppler ultrasound-technique (3D PDUS) in the diagnosis and documentation of tumours of the floor of the mouth. METHOD: 22 patients with tumours of the floor of the mouth (2 T1-, 5 T2-, 6 T3- and 9 T4-carcinomas) prospectively underwent conventional grey-scale ultrasound combined with power Doppler ultrasound and 3D PDUS (3-Scape). All examinations were performed with the "Sonoline Elegra Advanced" in combination with a 7.5 MHz transducer. Two independent observers compared the results regarding clear tumour margins, midline crossing, infiltration of the mylohyoid muscle, infrahyoidal tumour, contact to the mandible, contact to major vessels (such as the lingual, submental and/or facial artery), intra- and peritumoural vascularisation and judged the value of the 3D reconstruction method for documentation purpose. RESULTS: All parameters relevant for therapy could be gathered from the 3D data (agreement: 98.2%) almost without loss of information; results of both observers were identical (kappa value: 1.0). In the comparison to conventional ultrasound, 3D PDUS also allows for the reconstruction of axial images of the floor of the mouth similar to CT-images, and a 3D image of tumour vascularisation can be obtained. Acquisition and reconstruction of the 3D data only takes a couple of minutes. CONCLUSIONS: "3-Scape" is a novel easy-to-perform method allowing the complete acquisition of 3D data of the entire floor of the mouth, and providing the possibility to digitally store and/or transfer examination results without loss of information. Reconstruction of ultrasound-images in any desirable plane and/or as a 3D presentation is possible. Thus, in the future, additional software will facilitate the determination of the volume and the degree of vascularisation of tumours.

Adult↗
PubMed2000

[3D power Doppler ultrasound: new possibilities in the diagnosis and documentation of tumors of the base of the tongue].

BACKGROUND: To evaluate a novel 3-D power Doppler ultrasound technique (3-D PDUS) in the diagnosis and documentation of tumors of the base of the tongue. PATIENTS AND METHODS: Twenty patients with tumors of the base of the tongue (2T1, 6T2, 6T3, and 6T4 carcinomas) prospectively underwent two-dimensional gray scale and power Doppler ultrasound and 3-D PDUS (3-Scape). All examinations were performed with a 7.5 MHz transducer and the Sonoline Elegra Advanced. Two independent observers compared the examinations regarding clear tumor margins, maximal diameter of the tumor, midline crossing, infiltration of the mylohyoid muscle, infrahyoidal tumor, contact to the lingual artery, vascularization in the tumor and in surrounding tissue, and evaluated the documentary use of the 3-D reconstruction. RESULTS: All relevant pretreatment parameters were accessible in the 3-D data; results of both observers were almost identical. An acquisition and reconstruction of the 3-D data takes only a couple of minutes. In addition to two-dimensional ultrasound 3-D PDUS allows reconstruction of axial images of the base of the tongue similar to CT images and a 3-D visualization of tumor vascularization. CONCLUSIONS: 3-Scape is a novel user-friendly method that allows uninterrupted acquisition of large 3-D volumes, and digital storage and transmission of ultrasound studies without loss of information. US images can be reconstructed in any desired plane or visualized in 3-D. In the future, additional software will permit exact determination of the volume and degree of vascularization of tumors.

Adult↗
PubMed2000

The effect of interferon beta-1b treatment on MRI measures of cerebral atrophy in secondary progressive multiple sclerosis. European Study Group on Interferon beta-1b in secondary progressive multiple sclerosis.

The recently completed European trial of interferon beta-1b (IFNbeta-1b) in patients with secondary progressive multiple sclerosis (SP multiple sclerosis) has given an opportunity to assess the impact of treatment on cerebral atrophy using serial MRI. Unenhanced T(1)-weighted brain imaging was acquired in a subgroup of 95 patients from five of the European centres; imaging was performed at 6-month intervals from month 0 to month 36. A blinded observer measured cerebral volume on four contiguous 5 mm cerebral hemisphere slices at each time point, using an algorithm with a high level of reproducibility and automation. There was a significant and progressive reduction in cerebral volume in both placebo and treated groups, with a mean reduction of 3.9 and 2.9%, respectively, by month 36 (P = 0.34 between groups). Exploratory subgroup analyses indicated that patients without gadolinium (Gd) enhancement at the baseline had a greater reduction of cerebral volume in the placebo group (mean reduction at month 36: placebo 5.1%, IFNbeta-1b 1.8%, P < 0.05) whereas those with Gd-enhancing lesions showed a trend to greater reduction of cerebral volume if the patient was on IFNbeta-1b (placebo 2.6%, IFNbeta-1b 3.7%; P > 0.05). These results are consistent with ongoing tissue loss in both arms of this study of secondary progressive multiple sclerosis. This finding is concordant with previous observations that disease progression, although delayed, is not halted by IFNbeta. The different pattern seen in patients with and without baseline gadolinium enhancement suggests that part of the cerebral volume reduction observed in IFNbeta-treated patients may be due to the anti-inflammatory/antioedematous effect of the drug. Longer periods of observation and larger groups of patients may be needed to detect the effects of treatment on cerebral atrophy in this population of patients with advanced disease.

Adult↗
PubMed2000

In situ analysis of sulfate-reducing bacteria related to Desulfocapsa thiozymogenes in the chemocline of meromictic Lake Cadagno (Switzerland).

Comparative sequence analysis of a 16S rRNA gene clone library from the chemocline of the meromictic Lake Cadagno (Switzerland) retrieved two clusters of sequences resembling sulfate-reducing bacteria within the family Desulfovibrionaceae. In situ hybridization showed that, similar to sulfate-reducing bacteria of the family Desulfobacteriaceae, bacteria of one cluster with similarity values to the closest cultured relatives of between 92.6 and 93.1% resembled free cells or cells loosely attached to other cells or debris. Bacteria of the second cluster closely related to Desulfocapsa thiozymogenes DSM7269 with similarity values between 97. 9 and 98.4% were generally associated with aggregates of different small-celled phototrophic sulfur bacteria, suggesting a potential interaction between the two groups of bacteria.

DNA Probes↗
PubMed2000

Analysis of first-pass and delayed contrast-enhancement patterns of dysfunctional myocardium on MR imaging: use in the prediction of myocardial viability.

OBJECTIVE: The purpose of the study was to analyze first-pass and delayed contrast-enhancement patterns of dysfunctional myocardial regions on MR imaging after injection of gadopentetate dimeglumine to predict myocardial viability in patients with coronary artery disease. SUBJECTS AND METHODS: Twelve patients with wall motion abnormalities and related coronary artery disease revealed by conventional coronary angiography underwent MR imaging at 1.5-T before and 3 months after revascularization therapy. Short-axis images were acquired using a cine gradient-echo sequence. Each slice was divided into eight segments. Overall, 73 segments with impaired contractility were imaged during the first-pass and 14 +/- 2 min after injection of 0.05-mmol/kg gadopentetate dimeglumine at a flow of 3 ml/sec using a T1-weighted turbo fast low-angle shot sequence. Improved systolic wall thickening 3 months after revascularization served as the criterion of viability. RESULTS: At study entry, 26 dysfunctional segments showed delayed hyperenhancement compared with the adjacent functional segments within the same slice, and 47 did not reveal hyperenhancement. After revascularization, 25 (96%) of the 26 hyperenhanced segments did not recover function, whereas 39 (83%) of the 47 segments without hyperenhancement showed mechanical improvement. Segment-related sensitivity and specificity for the correlation of lack of delayed hyperenhancement with myocardial viability were 39 (98%) of 40 and 25 (76%) of 33, respectively. Hypoenhancement during first-pass did not serve as a reliable criterion of viability. CONCLUSION: Evidence of delayed hyperenhancement of dysfunctional myocardium may be used to predict lack of mechanical improvement or nonviability, whereas the lack of hyperenhancement can be correlated with improvement of regional contractility or viability after revascularization.

Aged↗
PubMed2000

Detection of pharyngeal perforation: comparison of aqueous and barium-containing contrast agents.

OBJECTIVE: We sought to assess the value of aqueous and barium-containing contrast agents in the detection of pharyngeal perforation. SUBJECTS AND METHODS: Visual and objective in vitro comparisons of an iodinated aqueous contrast agent, a 50% weight/volume barium suspension, and a 100% weight/volume barium suspension were performed. Moreover, to exclude pharyngeal perforation after surgery, we prospectively examined 109 patients by pharyngography, using the aqueous contrast agent and the 100% weight/volume barium suspension. All patients with a pharyngeal perforation were followed up clinically to exclude complications due to barium application. RESULTS: As opposed to the 100% weight/volume barium suspension, in vitro comparison between the aqueous contrast agent and the 50% weight/volume barium suspension yielded no substantial differences. Seventeen perforations could be detected with the aqueous contrast agent. Although 10 of 17 perforations could be slightly better visualized with the 100% weight/volume barium suspension, two perforations were missed with this agent. Five perforations were equally well detected with both. CONCLUSION: Because of a higher radiopacity, 100% weight/volume barium suspensions may more sharply delineate perforations. However, in contrast to aqueous contrast media, narrow pharyngeal perforations can be missed. Thus, the use of a 100% weight/volume barium suspension does not improve the detection of pharyngeal perforation.

Adult↗