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Biomedical subjects

G Adam

Publications and source records attributed to G Adam.

At least 55 records · Page 3Linked to original sources

[Transjugular liver biopsy: trucut or aspiration biopsy with modified Ross needles?].

PURPOSE: The transjugular liver biopsy is performed in patients with coagulopathy to evaluate diffuse hepatopathies. Using a jugular venous access, a liver vein is cannulated and a transvascular biopsy taken. The two techniques in use are the aspiration biopsy with a modified 15G or 16G Ross needle used for TIPS and the core biopsy with a Trucut needle. The sampling is quite similar for these techniques, but the costs are significantly different. This study is a meta-analysis of data published on both techniques to search for clinical evidence that justifies the use of the more expensive Trucut needle or that finds aspiration with the less expensive Ross needle equivalent. MATERIALS AND METHODS: The study includes 16 publications that were published between 1996 and 2002 and provided reliable information on technical success rate, complications and adequate histology. The data on 1374 procedures were analyzed, comprising 436 aspiration biopsies and 938 Trucut biopsies. RESULTS: Considering both procedures together, 95.9 % of the procedures were technically successful and 92.2% of the histologic samples diagnostically adequate. The technical success rate was 96.7 % for the Trucut-biopsies and 94.4 % for the aspiration biopsies. The corresponding rates of obtaining diagnostically adequate histologic samples were 92.5 % and 91.5 %, respectively. The complication rate of the entire population studied was 0.65 % without significant difference found between the two methods. With a list price of 420 Euro, the Trucut system costs about 200 Euro more than the Ross needle, which is listed as approximately 220 Euro. CONCLUSION: In the absence of any significant differences between both techniques for transjugular liver biopsies, economic considerations make the aspiration biopsy with the modified Ross needle preferable over the Trucut needle biopsy.

Biopsy, Needle↗

[Radiation exposure of the head, midface and pelvis in multi-slice CT (MSCT): comparison with single-slice CT (SSCT)].

PURPOSE: Comparison of the radiation exposure of the head, midface and pelvis in multi-slice CT (MSCT) and single-slice CT (SSCT) for manufacturer-implemented standard protocols. MATERIALS AND METHODS: An anthropomorphic Alderson-Rando phantom equipped with LiF-thermoluminescent dosimeters in the head, neck and pelvic region was examined with different MSCT and SSCT protocols, and the measured organ doses were compared. RESULTS: In comparison with the SSCT protocols, the MSCT protocols delivered about twice the organ dose to the head and pelvis and about eight times the organ dose to the midface. The comparison indicates that the parameters (slice collimation, mAs, pitch) used for the MSCT protocols deliver increased radiation doses. CONCLUSIONS: The current standard MSCT protocols generally lead to higher organ doses to the head, midface and pelvis than the SSCT protocols, raising the question whether using the MSCT protocols recommended by the manufacturer can be justified. The dose parameters should be optimized to achieve an acceptable balance of dose reduction and adequate image quality.

Equipment Design↗

[The role of angiography in the diagnosis and therapy of gastrointestinal hemorrhage].

PURPOSE: Evaluation of angiography in the diagnosis and treatment of acute and chronic gastrointestinal bleeding. MATERIALS AND METHODS: Thirty-seven consecutive patients with clinically suspected gastrointestinal bleeding underwent selective angiography of the visceral arteries. If technically possible, patients with radiologically proven hemorrhage underwent selective embolization with microcoils. Not all angiographically detected bleeding vessels were embolized. Clinical outcome was determined from a review of the medical records. RESULTS: 37 patients underwent 43 angiographies, which demonstrated 25 bleedings considered acute and 18 considered chronic. Seventeen patients had previous intestinal surgery. In 9 of the 37 patients, 12 of the 43 (sensitivity: 28 %) hemorrhages were detected. A postoperative bleeding was found in 6 patients. With one exception, all angiographically positive cases were clinically considered to be acute. Transcatheter embolization of the bleeding vessels with microcoils was performed in 6 patients, with 3 patients having the bleeding stopped permanently and 3 patients requiring further surgical treatment. In 3 patients, embolization was not possible for technical reasons. No complications attributable to angiography were seen. CONCLUSION: Angiography should be performed in patients with spontaneous and postoperative gastrointestinal bleeding. Transcatheter embolization is an effective and safe therapeutical option in both clinical settings.

Acute Disease↗

[MR-imaging of the breast at 0.5 Tesla: menstrual-cycle dependency of parenchymal contrast enhancement in healthy volunteers with oral contraceptive use?].

INTRODUCTION: To evaluate changes of contrast medium enhancement of the breast parenchyma due to menstrual cycle in healthy volunteers with oral contraceptive use in MR-imaging of the breast. MATERIAL AND METHODS: 15 healthy volunteers (age: 22 - 36, mean 28,2) without breast disease were examined two times during one menstrual cycle (days 7 - 14 and days 21 - 2). Two volunteers were examined only in the second part of the cycle (days 21 - 2). All volunteers used oral contraceptives for more than 6 month continuously. Examinations were performed with a 0,5 T magnet (dynamic 3D-gradient echo protocol with subtraction postprocessing). We evaluated the number of enhancing foci and the parenchymal contrast medium enhancement during the different phases of the cycle by region of interest. RESULTS: Only a total of two enhancing foci were found in 2 of 17 volunteers. Time/signal intensity diagrams in these both cases were not suspicious (< 80 % initial signal increase after of contrast medium injection, no wash-out phenomenon) and sonography of the breast in these two cases was inconspicuous. Contrast medium enhancement of breast parenchyma in cycle days 7 - 14 (mean enhancement: 0.12 - 0.26, minutes 1 - 9 p. i.) was not significantly different (p = 0.2209; Wilcoxon signed rank test) from cycle days 21 - 2 (mean: 0.13 - 0.32). CONCLUSION: Menstrual cycle dependency of parenchymal contrast medium enhancement seems to be of minor relevance for premenopausal women with use of oral contraceptives.

Adult↗

[Elastography: Quantitative imaging modality of the elastic tissue properties].

The wide range of elastic tissue properties and the difference in elasticity of tumors and the adjacent tissues have provided motivation for developing elasticity imaging techniques. These research efforts have converged with the development of a new imaging modality, the so-called elastography, with the acquired and processed images referred to as elastograms. This modality was pioneered for ultrasonic imaging, which provides the majority of experience on this topic. MR-elastography has been developed in recent years. The published clinical data range from the characterization of prostate and breast cancer in oncology and dynamic examinations of skeletal muscle to intravascular elastic differentiation of vessel plaques. Advantages of the ultrasonic elastography are ubiquitous applicability and cost-effectiveness. MR elastography offers improved reconstruction and the possibility to assess potential anisotropic properties. The different approaches of elastography, their technical and clinical application and the limitations known so far are reviewed in this paper.

Anisotropy↗

[Clinical relevance of cranial CT under emergency conditions--basic neuroradiologic investigations].

PURPOSE: To determine the diagnostic accuracy of cranial CT under emergency conditions. MATERIAL AND METHODS: Four hundred cranial CT examinations (cerebrum, petrosal bone, fascial bone, sinuses, orbita) were evaluated retrospectively and correlated with the initial neurologic examination, the discharge and surgical diagnoses, and the results of other imaging modalities (conventional X-Ray, MRI, angiography). The average age was 49 (2 to 89) years, with 42 % male and 58 % female patients. The discharge diagnosis was defined as the gold standard, assuming that clinical examinations and laboratory and imaging studies were maximized to establish the diagnosis, together with any possible surgery. RESULTS: Overall sensitivity, specificity and diagnostic accuracy was 85 %, 70 % and 82 % for cranial CT, 66 %, 45 % and 61 % for the initial neurologic examination, 79 % and 29 % for acute cerebral infarction, and 65% and 13% for intracranial bleeding. Correlation of the CT diagnoses to the discharge and surgical diagnoses was high (82 % and 80 %, respectively; p < 0.01), to the diagnosis of conventional x-ray moderate and to the diagnoses of angiography and MRI unsatisfactory (74 % and 68 % and 60 %, respectively; p > 0.05). Craniotomy was performed in 47 of 400 (12%) patients after cranial CT, within 12 hours in 29, in 12 to 24 hours in 8, and after 24 hours in 10 patients. The risk for intracranial bleeding in patients with a skull fracture was increased by a factor of 3.3. CONCLUSION: The high diagnostic accuracy of cranial CT in establishing a precise, timely and reproducible diagnosis confirms the important role of CT as primary diagnostic method under emergency conditions.

Adolescent↗

[Quality rating of MR-cholangiopancreatography with oral application of iron oxide particles].

PURPOSE: To compare image quality in magnetic resonance cholangiopancreatography (MRCP) performed with and without oral application of Lösferron (ferrous gluconate, Lilly Pharma, Hamburg). MATERIALS AND METHODS: A prospective study compares MRCPs performed on 52 patients with a 1.5 T clinical whole body scanner using a standard body coil. After randomization, patients ingested either 0.5 l of Lösferron (n = 27, group 1) or no oral contrast agent (n = 25, group 2) prior to the examination. 7 RARE (40 to 20 degrees) sequences were obtained, followed by selected 3 mm HASTE (T 2 -weighted with fat suppression) sequences. After blinding, image quality was rated by two radiologists using a scale of 1 (not discernible) to 5 (very well discernible). The following sections of the biliary ductal system were evaluated: left and right hepatic duct, extrahepatic bile duct and intrapancreatic bile duct. The pancreatic duct was evaluated by its location: head, body and tail of the pancreas. A Wilcoxon-Mann-Whitney test was used to determine significant differences (p < 0.05) between sampled ductal segments. Correction for multiple testing was applied. RESULTS: The oral application of Lösferron was well tolerated by all patients, and all sequences could be acquired and evaluated in all 52 patients. For the different sections of the biliary system, the mean ratings with and without Lösferron were, respectively, 3.28 and 3.36 for the left hepatic duct, 3.26 and 3.33 for the right hepatic duct, 3.46 and 4.0 for the extrahepatic bile duct, and 2.8 and 3.48 for the intrapancreatic bile duct. The corresponding ratings for the pancreatic duct were 2.8 and 3.24 for the pancreatic head, 2.84 and 3.38 for the pancreatic body, and 2.68 and 3.22 for the pancreatic tail. The differences with and without contrast agent were not statistically significant. Interobserver variability was between 0.37 for the pancreatic duct in the tail of the pancreas and 0.66 for the right hepatic duct. CONCLUSION: Despite the trend toward a better rating of the image quality for all sections of the pancreaticobiliary ductal system with Lösferron, a significant difference was not found in any ductal section after correction for multiple testing. Thus, we believe that the ingestion of Lösferron is not absolutely required prior MRCP.

Administration, Oral↗

[MRI in the diagnosis of non-compacted ventricular myocardium (NCVM) compared to echocardiography].

PURPOSE: To report the detection of non-compacted ventricular myocardium (NCVM) with MRI compared to echocardiography in 8 patients. MATERIAL AND METHODS: Non-compaction of the ventricular myocardium is a congenital disorder characterized by an altered structure of the myocardial wall resulting from an intrauterine arrest in endomyocardial embryogenesis. The morphological findings consist of a prominent meshwork of multiple myocardial trabeculations and deep intertrabecular recesses, communicating with the left ventricular cavity. 8 consecutive patients (mean age 7.3 years) with clinical and echocardiographic signs of NCVM were examined by MRI (1.5 T, Vision, Siemens) in short axis and 2- and 4-chamber views, using T (1)-weighted TSE and Cine-GRE in 6 patients and true FISP sequences in 2 patients. MRI and echocardiography were evaluated for visibility, signs of NCVM and involvement of myocardial wall segments. Thickness was measured for non-compacted and compacted myocardium and the non-compacted to compacted (N/C) ratio calculated. RESULTS: MRI diagnosed 6 of 8 patients of having NCVM. Myocardial thickness as measured by echocardiography and MRI showed a good correlation in compacted myocardium (r = 8.82) and no correlation in non-compacted myocardium (r = 0.4). In 2 cases, non-compacted myocardium was detected but echocardiography did not reach the N/C ratio > 2 as required to diagnose NCVM in accordance with the criteria found in the literature. Both patients were also misdiagnosed by MRI performed with Cine-GRE. MRI reached a N/C ratio > 2 in only three patients. Newer TruFisp sequences showed no definite advantages. Extent of non-compaction could be visualized correctly with MRI. CONCLUSION: Echocardiography is the method of choice to detect NCVM. MRI can be an alternative in some cases. The diagnosis of NCVM should not be considered until N/C ratio is over 2.

Adolescent↗

[Detection of liver lesions with gadolinium-enhanced VIBE sequence in comparison with SPIO-enhanced MRI].

PURPOSE: Detection of malignant liver lesions with gadolinium-enhanced volumetric interpolated breath-hold examination (VIBE) in comparison with SPIO-enhanced MRT (four different SPIO-enhanced T2w sequences) and histological and imaging follow-up in non-cirrhotic livers at 1.5 T. PATIENTS AND METHODS: Twenty-two patients with suspected focal liver lesions prospectively underwent a gadolinium-enhanced 3D VIBE. Four T2w sequences (HASTE sequence, fast spin-echo-sequence with and without fat-saturation, FLASH 2D gradient echo-sequence) after administration of superparamagnetic iron oxide (SPIO) served as gold standard combined with histological work-up in 17 patients and histological and imaging follow-up in five patients. The image quality was evaluated and the detectability of intrahepatic lesions was rated by the alternative free-response receiver operating characteristic (AFROC) analysis. In addition, the contrast-to-noise ratio was compared. RESULTS: Altogether 49 malignant and 35 benign liver lesions were found. Concerning the image quality, VIBE turned out to be of slightly poorer image quality than the SPIO-enhanced examination with HASTE sequence (4.95 vs. 5.0). The fast spin-echo-sequence without fat-saturation demonstrated the highest contrast-to-noise ratio. All sequences showed a comparable certainty in detecting lesion (area under the curve 0.68-0.73) and identifying malignant liver lesions. CONCLUSION: Despite the small number of patients, VIBE seems to be a comparable, inexpensive and fast method in diagnosing malignant liver lesions.

Adult↗

[Marfan syndrome: pathogenesis, phenotypes and diagnostic value, of various imaging techniques].

Marfan syndrome is a genetic disorder with autosomal dominant inheritance. It is caused by mutations in the fibrillin-1 gene and leads to different disease manifestations. Seventy-five percent of the affected individuals develop an aneurysm of the ascending aorta, 41 % suffer from aortic dissections, and 93 % die of cardiovascular diseases. Skeletal changes occur in two-thirds of the patients, and lens dislocation is observed in 60 to 80 %. Without treatment, the life expectancy is 32 +/- 16 years. However, Marfan patients can live up to 60 years if they receive optimal therapy. Early diagnosis of the disease and it 's life-threatening sequelae is the prerequisite for early therapy. Radiologic diagnostic techniques are of pivotal importance in this context as they allow the identification of major and minor disease manifestations and the detection of severe dilatations and aortic dissections at an early stage. This overview describes the radiologically detectable multiple changes seen in Marfan syndrome and explains the diagnostic value of various imaging techniques in the diagnosis and therapy of Marfan syndrome.

Bone and Bones↗

3D-imaging of the facial skeleton with an isocentric mobile C-arm system (Siremobil Iso-C3D).

OBJECTIVES: The purpose of this study was to compare three-dimensional (3D) imaging of the facial skeleton using an isocentric mobile C-arm system vs CT. METHODS: A dried human skull was scanned using a Siremobil Iso-C3D and a multi-detector CT (SOMATOM Volume Zoom; Siemens Medical Solutions, Erlangen, Germany) to compare reconstructed data sets. For each group of scans a standard protocol and a high resolution protocol were used. Image quality was analysed using six anatomical and six virtual structures in the primary reconstructed axial images of both data sets of the Siremobil Iso-C3D compared with CT. A receiver operating characteristic (ROC) study was performed with six examiners. RESULTS: The original categorical response data revealed no significant differences in sensitivity and specificity (P < 0.05). However, image quality of the reconstructed images of the Siremobil Iso-C3D was inferior to the CT images, with metal artefacts having a more prominent negative effect. CONCLUSIONS: The Siremobil Iso-C3D produces 3D images of the facial skeleton suitable for imaging osseous structures. No significant differences were found in sensitivity or specificity between the two methods. Metal objects degrade the image from the Iso-C method to a greater extent than those from CT.

Artifacts↗

Aneurysmal bone cyst: value of MR imaging and conventional radiography.

Our objective was to investigate the accuracy and the diagnostic value of different imaging features of primary aneurysmal bone cysts (ABC) in conventional radiographs and MRI. Conventional radiographs and MR images of 34 patients with a suspected aneurysmal bone cyst were reevaluated by six independent radiologists in a blinded fashion. Morphological features, MR signal characteristics, and contrast enhancement patterns were assessed. Diagnoses were correlated with histology. Sensitivity and specificity of the different imaging findings for each imaging technique were calculated. In 24 patients ABC was histologically proven. In 10 cases diagnoses other than ABC were established. Conventional radiography and MRI each demonstrated a sensitivity of 76.4 and 77.8% with a specificity of 55.0 and 66.7%, respectively. With combined use of both imaging modalities sensitivity and specificity increased to 82.6 and 70%, respectively. The ABC was significantly more often seen as circumscribed lesion with bone expansion, lobulation, septa, and pathological cortical bone reaction than those cases with different diagnoses. Septal contrast enhancement proved to be a useful MR imaging finding in suspected ABC. The combined use of conventional radiographs and MRI revealed the highest sensitivity in the diagnosis of ABC in relation to histology. Magnetic resonance imaging provides improved diagnostic specificity and valuable information on soft tissue changes.

Adolescent↗

Action of brassinosteroids in the cotton leafworm Spodoptera littoralis.

The two native plant hormones 24-epibrassinolide and 24-epicastasterone showed 50% competition for binding at IC(50) of 1-3.6 microM with [(3)H]ponasterone A using cultured imaginal wing discs from last-instar larvae of the cotton leafworm, Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae). However, culture of imaginal wing discs in different concentrations of brassinosteroids, even up to 100 microM, demonstrated no induction of evagination. In contrast, 20E and the non-steroidal agonist RH-5992 competed respectively about 23- and 42-fold more effectively with labeled ponasterone A, and their ability (EC(50)) to induce disc evagination in vitro was 158 and 87 nM, respectively. Injection of 10 microg of brassinosteroids in newly-moulted last-instar larvae did not cause mortality above controls; higher mortalities were scored when brassinosteroids were injected late in the last instar.

Animals↗

A combined pharmacological and genetic approach to investigate the role of orphanin FQ in learning and memory.

Using a combination of the selective opioid receptor-like1 (ORL1) receptor agonist, Ro 64-6198, and orphanin FQ/nociceptin (OFQ/N) peptide knockout (KO) mice, the influence of OFQ/N on cognition has been studied in the rodent. In wild type, C57BL/6J mice, Ro 64-6198 (0.3-1 mg/kg i.p.) impaired the acquisition of spatial learning in the Morris water maze, although a mild neurological impairment was evident which complicated precise interpretation. In Lister hooded rats, Ro 64-6198 (6 mg/kg i.p.) produced delay dependent impairments in rats performing either a delayed matching or a delayed nonmatching to position task with only a modest (< 20%) effect on omissions - an effect consistent with a short-term memory impairment. Electrophysiological studies demonstrated an inhibitory effect of OFQ/N on LTP recorded from the CA1 region of wild type mice, but not in ORL1 receptor knockout mice. In contrast to the ORL1 agonist, mice deficient in the OFQ/N peptide showed some evidence of improved spatial learning, fear conditioning and passive avoidance retention. However, CA1 LTP was similar between OFQ/N peptide KO mice and wild type controls. Subsequent receptor radioautography studies demonstrated the presence of ORL1 receptors within various regions of the medial temporal lobe system: i.e. CA1, dentate gyrus molecular layer, subiculum, perirhinal cortex. Taken together, these results suggest a bi-directional effect of OFQ/N containing systems on aspects of cognitive behaviour, particularly those elements associated with hippocampal function. This is consistent with a likely modulatory role of OFQ/N on hippocampal and associated cortical circuitry.

Animals↗

[Value of triple phase helical CT for the detection of hepatocellular carcinoma in cirrhotic liver].

PURPOSE: Purpose of this study was to determine the value of the delayed-phase (DP) of helical CT in the detection of hepatocellular carcinoma (HCC) in cirrhotic liver in comparison to the arterial phase (AP) and the portal-venous phase (PP). MATERIAL AND METHODS: 51 patients with liver cirrhosis and suspected HCC were examined by triple-phase helical-CT (THCT). Images were standardized and obtained 20 seconds - AP, 60 - 70 seconds - PP, and 300 seconds - DP after injection of 140 ml of intravenous iodinated contrast material. Pictures were reviewed by two experienced radiologists for typical intrahepatic lesions. First, each single phase of contrast distribution were seen separately. Then all contrast phases were reviewed together. RESULTS: In 17 patients 49 typical lesions were found, histological work-up was performed, whereas in 34 patients clinical follow-up of at least 6 months was obtained. The arterial phase (AP) itself depicted 55 % of these lesions, whereas the portal-venous phase (PP) depicted 57 % and the delayed phase 78 %. DP showed a significantly higher detection rate in comparison to the PP (p = 0.008). By performing a biphasic helical CT 40 lesions would have been detected with AP and PP, whereas all 49 lesions would have been visualised by combining AP and DP. This means a significantly higher detection rate for AP/DP instead of using AP/PP (p = 0.031). CONCLUSION: Additionally to the AP and PP, a delayed phase should be performed when cirrhosis is present. Even though AP and DP depicted all HCC's in this study, the PP provides undispensable additional information, so that, in our opinion, a THCT should be given preference when HCC is suspected.

Adult↗

Functional magnetic resonance imaging (fMRI) for fetal oxygenation during maternal hypoxia: initial results.

PURPOSE: To investigate the potential of fMRI to measure changes in fetal tissue oxygenation during acute maternal hypoxia in fetal lambs. MATERIAL AND METHODS: Two ewes carrying singleton fetuses (gestational age 125 and 131 days) underwent MR imaging under inhalation anesthesia. BOLD imaging of the fetal brain, liver and myocardium was performed during acute maternal hypoxia (oxygen replaced by N 2 O). Maternal oxygen saturation and heart rate were monitored by a pulse-oxymeter attached to the maternal tongue. RESULTS: Changes of fetal tissue oxygenation during maternal hypoxia were clearly visible with BOLD MRI. Signal intensity decreases were more distinct in liver and heart ( approximately 40 %) from control than in the fetal brain ( approximately 10 %). CONCLUSIONS: fMRI is a promising diagnostic tool to determine fetal tissue oxygenation and may open new opportunities in monitoring fetal well being in high risk pregnancies complicated by uteroplacentar insufficiency. Different signal changes in liver/heart and brain may reflect a centralization of the fetal blood flow.

Animals↗

MR elastography of the breast:preliminary clinical results.

PURPOSE: Imaging of breast tumors and various breast tissues using magnetic resonance (MR) elastography (MRE) to explore the potential of elasticity as a new parameter for the diagnosis of breast lesions. METHODS: Low-frequency mechanical waves are transmitted into breast tissue by means of an oscillator. The local characteristics of the mechanical wave are determined by the underlying elastic properties of the tissue. Theses waves can be displayed by means of a motion-sensitive spin-echo MR sequence within the phase of the MR image. Elasticity reconstruction is performed on the basis of 8 "snapshots" of each wave within the three spatial directions. We performed in-vivo measurements in 15 female patients with malignant tumors of the breast, 5 patients with benign breast tumors, and 15 healthy volunteers. RESULTS: Malignant invasive breast tumors documented the highest values of elasticity with a median of 15.9 kPa and a wide range of stiffnesses between 8 and 28 kPa. In contrast, benign breast lesions represented low values of elasticity, which were significantly different from malignant breast tumors (median elasticity: 7.0 kPa; p = 0.0012). This was comparable to the stiffest tissue areas in healthy volunteers (median elasticity 7.0 kPa), whereas breast parenchyma (median: 2.5 kPa) and fatty breast tissue (median: 1.7 kPa) showed the lowest values of elasticity. Two invasive ductal carcinomas had elasticity values of 8 kPa and two stiff parenchyma areas in healthy volunteers had elasticities of 13 and 15 kPa. These lesions could not be differentiated by their elasticity. CONCLUSION: We conclude that MRE is a promising new imaging modality with the capability to assess the viscoelastic properties of breast tumors and the surrounding tissues. However, from our preliminary results in a small number of patients it is obvious that there is an overlap in the elasticity ranges of soft malignant tumors and stiff benign lesions.

Adult↗