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Biomedical subjects

M Düx

Publications and source records attributed to M Düx.

At least 19 recordsLinked to original sources
PubMed2005

[Prevalence of latent and manifest hyperthyroidism in an iodine-deficient area: non-selected patient population admitted for CT studies with iodine-containing contrast agents].

PURPOSE: To evaluate the prevalence of latent and manifest hyperthyroidism in a non-selected group of patients admitted for contrast enhanced CT studies blood samples were tested for the levels of thyroid-stimulating hormone (TSH). MATERIAL AND METHODS: TSH blood levels were obtained in 548 consecutive patients who were scheduled for contrast-enhanced (Iopromide; 300 mg iodine/ml) CT scanning. In case of TSH levels < 0.4 mU/l, blood samples were also tested for triiodothyronine (T3) and tetraiodothyronine (T4) blood levels, and treatment with Irenat (sodium perchlorate) was commenced before scanning. In case of TSH levels < 0.1 mU/l, CT scanning was not performed but further evaluation of the thyroid function was initiated. RESULTS: TSH blood levels ranged from 0.4 to 7.5 mU/l in 512 patients, and 36 patients (6.6%) had TSH blood levels < 0.4 mU/l and 9 patients blood levels < 0.1 mU/l, with 32 of those patients (5.8%) having regular T3 and T4 blood levels consistent with latent hyperthyroidism. In 4 patients (0.8%), T3 or T4 blood levels were increased consistent with manifest hyperthyroidism. CONCLUSION: In South Germany, the prevalence of latent or manifest hyperthyroidism in a non-selected patient group is high. Therefore TSH blood levels should be obtained prior to contrast-enhanced CT studies.

Adult↗
PubMed2005

[Experimental testing of a new coil design for endoluminal MRI applied to the pig stomach].

PURPOSE: Experimental feasibility study of a new MR-Coil concept for enhanced visualization of the gastric wall. MATERIAL AND METHODS: The newly developed single-loop receiver coil for endoluminal imaging (Fraunhofer Institute, St. Ingbert, Germany) was evaluated in 4 explanted pig stomachs in a 1.5T MR unit (Siemens Symphony, Erlangen, Germany) with T1 w and T2 w MR sequences in three planes. The new coil consists of a foldable and self-expanding single loop coil (receiver coil) of a shape memory metal (nitinol). It was covered with a biocompatible material (silicone) to prevent direct contact of the wire with stomach tissue. The coil assumes a circular configuration with a diameter of 8 cm because of its memory metal properties. The flexible characteristics of the material used allow the passage through the instrument channel (13 mm diameter) of a specially designed MR-compatible endoscope. The purpose of our study was to assess feasibility of the coil design as a first step in developing a new endoluminal MRI-concept. Additionally the number and signal intensity of visible gastric wall layers were evaluated and findings were correlated with histopathological results of a pig stomach. RESULTS: The new coil concept was a feasible system in all 4 cases and showed good image quality for analysis. On T1 w images, 3 layers were visible in all cases, and on T2 w images 4 different gastric wall layers were seen in 2 cases. Due to histopathological correlation, the different gastric wall layers were identified as follows: mucosa, submucosa and muscularis propria if three layers were depicted; in cases of 4 visible wall layers, serosa and subserosa could be detected additionally. For each gastric wall layer, a distinct signal intensity was found. CONCLUSION: The new MR coil concept for endoluminal imaging proved to be a feasible technique. Good differentiation of gastric wall layers in the pig stomach could be demonstrated. We have shown that endoscopic MR-imaging with our new coil concept is a valuable technique for the visualization of gastric wall layers. Due to this fact, follow-up studies including assessing safety aspects are necessary to finally conduct an experimental-clinical study on in-vivo human gastric specimens to detect tumor growth and morphology within the gastric wall. Endoscopic MRI may have the potential in the future to overcome today's limitations of diagnostic imaging in gastric cancer.

Animals↗
PubMed2004

[Imaging methods in the diagnosis and therapy of cystic echinococcosis].

Imaging studies, ultrasonography, play a central role for the diagnosis and follow-up of cystic echinococcosis (hydatid disease) due to the non-specific clinical symptoms and still inadequate sensitivity and specificity of currently available serological tests. Due to the increasing number of people immigrating to central Europe from countries with a high incidence of cystic echinococcosis, cystic echinococcosis has become an important differential diagnosis of cystic lesions. The imaging modality to localize and stage the disease depends on the organs affected. Ultrasonography is the most important imaging technique to screen for abdominal lesions (more than 75 % of the cases). Therefore, an expert committee of the WHO Working Group on echinococcosis has recently suggested a standardized ultrasonographic classification of hepatic cystic echinococcosis. This classification proofs to be very useful for staging echinococcal cysts with respect to parasite activity. Ultrasonography is not only an excellent tool for the primary diagnosis and therapeutic decision but also for follow-up of patients treated for cystic echinococcosis. Indications for computed tomography or magnetic resonance tomography are restricted to extra abdominal disease, patients not suited for ultrasonography because of obesity or meteorism, complicated cysts and planning of surgery or interventional therapy. Apart from surgery three other treatment options are well established: (1) chemotherapy with albendazole or mebendazole, (2) percutaneous drainage and sterilization (PAIR) and (3) observation of inactive echinococcal stages ("watch and wait" approach).

Albendazole↗
PubMed2004

[Diagnosis and staging of pancreatic carcinoma: MRI versus multislice-CT -- a prospective study].

PURPOSE: To evaluate multislice-CT versus MRI in the diagnosis and staging of pancreatic carcinoma in a prospective multi-reader analysis. MATERIALS AND METHODS: Fifty patients with suspected pancreatic carcinoma underwent both multislice-CT (4-Row, "hydro-technique") and state-of-the-art MRI (two 1.5 T units). In correlation with histopathologic findings or in case of a non-lesion diagnosis by follow-up (6-month interval), we evaluated MRI versus CT in a multi-reader analysis (2 reader pairs) for: 1. diagnostic quality; 2. examination time; 3. accuracy of potential resectability; 4. kappa analysis of observer variations; and 5. overall diagnostic reliability. RESULTS: A total of 28 lesions (n = 22 malignant, n = 6 benign) were present in the cohort group versus 22 patients without a focal lesion (n = 10 pancreatitis, n = 12 no tumor). For lesion detection, CT had a sensitivity of 100/89 % (reader pair 1/2) and specificity of 77 %, and MRI had a sensitivity of 75/89 % and specificity of 77/73 %. For the subgroup of adenocarcinomas of the pancreas (n = 17), we found a sensitivity of 100 % and a specificity of 61 % for CT versus a sensitivity of 82/94 % and a specificity of 67/61 % for MRI. The accuracy for determining the resectability was 91/82 % for CT and 90/82 % for MRI. The kappa analysis showed a good correlation for CT (0.71) and a moderate correlation of both groups for MRI (0.49). CONCLUSION: CT and MRI showed comparable results in the detection of pancreatic carcinomas as well as in the determination of resectability. Chronic pancreatitis as a "tumor-like-lesion" was the major factor of a missed diagnosis. The results of multi-reader analysis for both reading groups were almost identical with a moderate to good kappa correlation. There is no reason to prefer MRI (more expensive) over CT for patients with the presumptive diagnosis of pancreatic cancer.

Adenocarcinoma↗
PubMed2004

[Long-term results of interventional treatment of large unresectable hepatocellular carcinoma (HCC): significant survival benefit from combined transcatheter arterial chemoembolization (TACE) and percutaneous ethanol injection (PEI) compared to TACE monotherapy].

PURPOSE: A retrospective analysis of long-term efficacy of combined transcatheter arterial chemoembolization (TACE) and percutaneous ethanol injection (PEI) and TACE monotherapy was conducted in patients with large, non-resectable hepatocellular carcinoma (HCC). METHODS AND MATERIALS: Fifty patients with large, unresectable HCC lesions underwent selective TACE. Liver cirrhosis was present in 42 patients, due to alcohol abuse (n = 22) and viral infection (n = 17). In three patients, the underlying cause for liver cirrhosis remained unclear. Child A cirrhosis was found in 22 and Child B cirrhosis in 20 patients. Repeated and combined TACE and PEI were performed in 22 patients and repeated TACE monotherapy was performed in 28 patients. Survival and complication rates were determined and compared. RESULTS: The 6-,12-, 24- and 36-month survival rates were 61 %, 21 %, 4 %, and 4 % for TACE monotherapy and 77 %, 55 %, 39 % and 22 % for combined TACE and PEI (Kaplan-Meier method). The kind of treatment significantly affected the survival rate (p = 0.002 log-rank test). Severe side effects were present in two patients of the monotherapy group and in three patients of the combination therapy group. CONCLUSION: The combination of TACE and PEI is an effective and safe method in the palliative treatment of large HCC that has the potential of improving long term survival compared to TACE monotherapy.

Adult↗
PubMed2003

[Interventional therapy in renal artery dissection due to renal artery PTA. Case report].

Percutaneous angioplasty of a renal artery stenosis may lead to dissection and acute thrombosis that may put the organ at risk. In this case, it should be discussed individually how to treat the patient and the decision on interventional therapy should be based on interdisciplinary consensus. Local fibrinolysis usually allows to recognize the cause of obstruction which then is the basis for further treatments. The case report presented in this article describes how a dissection involving two thirds of the renal artery and leading to significant obstruction may successfully be treated by means of interventional radiology.

Angiography↗
PubMed2003

[The value of CT for the diagnosis of acute diverticulitis].

PURPOSE: In acute diverticulitis accurate diagnosis and staging are mandatory to decide on the treatment of the patient. The impact of computed tomography (CT) on the treatment of acute diverticulitis will be discussed. MATERIAL AND METHOD: CT is performed after distension of the distal colon by means of positive,water-soluble contrast media to depict intestinal perforation or penetration. Then intravenous contrast material is administered and spiral scanning is repeated to judge enhancement patterns of the abdominal structures/organs especially of the intestinal wall and to diagnose abscess formation. CT-morphologies of different stages of acute diverticulitis will be described. RESULTS: CT imaging is the only diagnostic method that in case of an acute diverticulitis combines safety with accuracy. On the one hand, it is fast and therefore safe with respect to patient control and on the other hand, it allows accurate staging of the inflammatory process reaching a sensitivity and specificity of up to 100%, each. CT is an appropriate tool to diagnose acute diverticulitis complicated by abscess formation, intestinal penetration or perforation and therefore has direct impact on the treatment of the patient. DISCUSSION: If acute diverticulitis is suspected CT is the method of choice for imaging because of its high impact on the choice of therapy and on the management of complications.

Acute Disease↗
PubMed2002

Preoperative evaluation of living renal donors: value of contrast-enhanced 3D magnetic resonance angiography and comparison of three rendering algorithms.

The aim of this study was to assess the value of contrast-enhanced three-dimensional MR angiography (CE 3D MRA) in the preoperative assessment of potential living renal donors, and to compare the accuracy for the depiction of the vascular anatomy using three different rendering algorithms. Twenty-three potential living renal donors were examined with CE 3D MRA (TE/TR=1.3 ms/3.7 ms, field of view 260-320x350 mm, 384-448x512 matrix, slab thickness 9.4 cm, 72 partitions, section thickness 1.3 mm, scan time 24 s, 0.1 mmol/kg body weight gadobenate dimeglumine). Magnetic resonance angiography data sets were processed with maximum intensity projection (MIP), volume rendering (VR), and shaded-surface display (SSD) algorithms. The image analysis was performed independently by three MR-experienced radiologists recording the number of renal arteries, the presence of early branching or vascular pathology. The combination of digital subtraction angiography (DSA) and intraoperative findings served as the gold standard for the image analysis. In total, 52 renal arteries were correspondingly observed in 23 patients at DSA and surgery. Other findings were 3 cases of early branching of the renal arteries, 4 cases of arterial stenosis and 1 case of bilateral fibromuscular dysplasia. With MRA source data all 52 renal arteries were correctly identified by all readers, compared with 51 (98.1%), 51-52 (98.1-100%) and 49-50 renal arteries (94.2-96.2%) with the MIP, VR and SSD projections, respectively. Similarly, the sensitivity, specificity and accuracy was highest with the MRA source data followed by MIP, VR and SSD. Time requirements were lowest for the MIP reconstructions and highest for the VR reconstructions. Contrast-enhanced 3D MRA is a reliable, non-invasive tool for the preoperative evaluation of potential living renal donors. Maximum intensity projection is favourable for the processing of 3D MRA data, as it has minimal time and computational requirements, while having similar or superior accuracy for the depiction of vessel anomalies or pathology compared with VR and SSD, respectively.

Algorithms↗
PubMed2002

[MR imaging of gastric wall layers in vitro: correlation to thehistologic wall structure].

PURPOSE: To correlate gastric wall layers visible of MRI with the anatomical structure of the gastric wall. METHODS: After macroscopic preparation 5 x 5 cm post-mortem tissue sections of the gastric antrum were evaluated using a 2.4 Tesla MR unit (Bruker, Ettlingen, Germany). MR imaging consisted of T2-weighted multi-spinecho sequences in longitudinal and axial directions. The specimens then were stained with hematoxylin-eosin for histological examination. After that histological correlation of the gastric wall layers visible on MRI was performed. RESULTS: In all specimens four gastric wall layers could be clearly identified on MRI. The direct comparison of those layers to the histological findings showed the following correlation: 1) intermediate signal = mucosa, 2) hypointense signal = lamina muscularis mucosae, 3) hyperintense signal = submucosa, 4) intermediate signal = muscularis propria. CONCLUSIONS: Gastric wall layers visible on MRI were successfully correlated to the anatomic layers of the gastric wall. This allows us for the first time to classify invasion of gastric carcinoma using high spatial-resolution MR imaging. However, the subserosa and serosa are excluded from this conclusion, because so far a reliable statement concerning the value of MRI to depict these very variable layers is not possible.

Cadaver↗
PubMed2002

[Prospective comparison of hydrosonography, endosonography and specimen sonography for TN staging of gastric carcinoma].

PURPOSE: To compare hydrosonography (HUS), endosonography (EUS) and experimental sonography (PUS) with respect to TN-staging accuracy of gastric carcinoma. MATERIAL AND METHODS: Thirty-six patients with gastric carcinoma underwent EUS (7.5/12 MHz transducer, Olympus GF-UM 20) and HUS (3.75 MHz transducer, Toshiba, Sonolayer SSA-270A) for TN-staging according to the UICC-classification. The resected specimens were reexamined (3.75/7.5 MHz transducer) and again TN-staging was performed. Findings were correlated with histopathological results. RESULTS: T- and N-staging accuracies were as follows: EUS 54 % (19/35) and 79 % (27/34); HUS 41 % (15/37) and 61 % (22/36); and PUS 51 % (19/37) and 72 %(26/36). Sensitivities and specificities for the detection of lymph node metastases were as follows: EUS 87 % and 54 %; HUS 57 % and 69 %; and PUS 83 % and 54 %. CONCLUSIONS: The accuracy of sonographic TN- staging is limited in patients with gastric carcinoma. Nevertheless, EUS may contribute to the preoperative management of patients with gastric carcinoma if indications are well defined. HUS is not suited for TN-staging of gastric carcinoma.

Adult↗
PubMed2001

[Recurrence of cystic adventitial degeneration of the popliteal artery--magnetic resonance tomography and MR angiography].

Adventitial cystic disease is a rare disorder characterized by mucin-containing cysts of the adventitial tissue. The condition has a predilection for the popliteal artery. Men are predominantly affected, usually around the fourth decade. We report of a case of recurrent adventitial cystic disease and the possibilities of modern cross-sectional imaging. In particular we discuss the advantages of magnetic resonance imaging and magnetic resonance angiography for the diagnosis of this condition. Furthermore, the etiology and the possibilities of surgical treatment are illustrated.

Arterial Occlusive Diseases↗
PubMed2001

[MRI in chronic inflammatory bowel disease].

Chronic inflammatory bowel disease is diagnosed and monitored by the combination of colonoscopy and small bowel enteroklysis. Magnetic resonance imaging has become the gold standard for the imaging of perirectal and pelvic fistulas. With the advent of ultrafast MRI small and large bowel imaging has become highly attractive and is being advocated more and more in the diagnostic work up of inflammatory bowel disease. Imaging protocols include fast T1-weighted gradient echo and T2-weighted TSE sequences and oral or rectal bowel distension. Furthermore, dedicated imaging protocols are based on breath-hold imaging under pharmacological bowel paralysis and gastrointestinal MR contrast agents (Hydro-MRI). High diagnostic accuracy can be achieved in Crohn's disease with special reference to the pattern of disease, depth of inflammation, mesenteric reaction, sinus tract depiction and formation of abscess. In ulcerative colitis, the mucosa-related inflammation causes significantly less bowel wall thickening compared to Crohn's disease. Therefore with MRI, the extent of inflammatory changes is always underestimated compared to colonoscopy. According to our experience in more than 200 patients as well as the results in other centers, Hydro-MRI possesses the potential to replace enteroklysis in the diagnosis of chronic inflammatory bowel disease and most of the follow-up colonoscopies in Crohn's disease. Further technical improvements in 3D imaging will allow interactive postprocessing of the MR data.

Adult↗
PubMed2001

[Prospective study to compare high-resolution computed tomography and magnetic resonance imaging in the detection of pancreatic neoplasms: use of intravenous and oral MR contrast media].

PURPOSE: To compare thin-section hydro-CT and MRI in the detection of pancreatic neoplasms. Evaluation of an oral, superparamagnetic contrast agent (OMP) for pancreatic MRI. MATERIAL AND METHODS: 45 patients with suspected pancreatic neoplasms were examined with consecutive thin-section helical CT (Hydro-CT, 3/6/3, 130 ml Ultravist, Schering) and MRI (1.0 T, breath-holding, T1w-GRE, T1w-GRE fat-sat, T2w-TSE). The MRI protocol included precontrast studies, studies after oral administration of OMP (Abdoscan, Nycomed Amersham) and studies after administration of OMP and Gadodiamide i.v. (Omniscan, Nycomed Amersham). All images were assessed by two independent radiologists in a blinded fashion. Radiologic diagnosis was correlated with histology or clinical follow-up (> or = 3 month). RESULTS: 39 patients could be included in analysis. In 13 cases a pancreatic neoplasm was proven by histology. Thin-section hydro-CT and MRI showed no statistically significant differences for the detection of pancreatic neoplasia. The sensitivity of helical hydro-CT was superior compared to MRI (88.5% vs. 65.44/73.1%/76.9%). The specificity of MRI was superior compared to helical hydro-CT (86.5% vs. 94.2%/90.4%/88.5%). CONCLUSION: Thin-section hydro-CT and MRI show similar results for the detection of pancreatic neoplasms. Compared to thin-section helical CT, MRI still has the drawbacks of much more time consumption and, still, lower spatial resolution. The use of an oral, superparamagnetic contrast agent added no advantage for pancreatic MRI.

Administration, Oral↗
PubMed2000

[Klippel-Trénaunay syndrome with involvement of the rectum. Surgical therapy after interventional-radiologic preparation].

Abdominal organs such as the rectum and urinary bladder are rarely involved in Klippel-Trénaunay syndrome, but may occasionally be the source of severe blood loss. Since frequently no isolated source of bleeding is identified, severe blood loss can result in a critical condition. This article describes an unusual multimodal treatment concept for a patient with Klippel-Trénaunay syndrome associated with severe recurrent rectal bleeding. We present the case of a 39-year-old patient with Klippel-Trénaunay syndrome and a history of rectal bleeding since childhood requiring multiple blood transfusions over the years. He was referred to our department in a state of continuous rectal bleeding. Preoperative work-up revealed a complete alteration of the rectum and the distal parts of the sigmoid/colon by hemangiomas, with diffuse bleeding from the destroyed rectal mucosa. Preoperatively the superior rectal artery was embolized. After a 48-h interval, sphincter-preserving complete rectal excision including the sigmoid/colon was performed followed by a colon pouch anal anastomosis and protective loop ileostomy.

Adult↗
PubMed2000

[Carcinoma of the stomach. Role of imaging for primary diagnosis and preoperative tumor staging].

The aim of imaging of gastric carcinoma has to be to diagnose the carcinoma as early as possible and to sort out the tumors that are resectable. At the same time imaging of gastric carcinoma should reduce the number of futile laparotomies in patients with advanced, non-resectable tumors to a minimum. Today, endoscopy is the method of choice to diagnose gastric carcinoma. Endosonography is advantageous if small carcinomas have to be judged for depth of tumor infiltration (early gastric carcinoma vs. advanced gastric carcinoma) because high resolution images of the gastric wall are obtained. Staging of large carcinomas that have grown beyond the gastric wall is best performed by hydro-CT because CT scans most accurately delineate infiltrations of surrounding organs/structures and help to plan surgery. Nowadays MRI is not suited for gastric imaging. MRI, however, has the highest potential to fundamentally improve staging of gastric carcinoma if high resolution imaging of the gastric wall is combined with screening for metastases in one examination.

Humans↗
PubMed1999

[Angiography and interventional radiology of the kidney].

For imaging of renal pathology a broad spectrum of radiologic diagnostic procedures are available which are, sometimes and particularly more recently, competing among each other in their diagnostic yield and relevance. For tumorous lesions ultrasound, computed tomography and magnetic resonance imaging are performed predominantly. Angiography is no longer required with the exception of highly selected cases and in some specific preoperative workup requirements. Until recently, catheter based digital subtraction angiography has been considered as gold standard. However, non-invasive techniques such as CT-angiography and MR-angiography are evolving parallel to their quantum leap of resolutions and readiness to use. Nevertheless, well accepted criteria for quality assessement of these new modalities are still lacking. More comparison studies are urgently warranted. Despite the availability of ultrashort pulse sequences applying the T1 relaxation reduction effect of gadolinium enhanced MR techniques overestimation of renal artery stenosis still poses a substantial problem. Renal intervention implies a variety of procedures such as plain angioplasty, stent placement, embolization of traumatic and both benign and malignant tumors. These methods have emerged over the last two decades from a more experimental nature to a fully accepted treatment option. When renal artery angioplasty is embedded in an aggressive approach including stenting as an adjunct for more complex cases, renal ostial lesions and a well organized follow-up regimen its therapeutic potential for treatment of renal insufficiency, malignant hypertension, for organ preservation bears a very high potential. Provided adequat periinterventional drug regimen restenosis rates may be as low as 10%. In highly selected cases capillary embolization might be used as an alternative to nephrectomy with a similar clinical outcome. Particularly the development of superselective small caliber embolization catheters parallel to further refinement of embolization material has aided to use superselective occlusion techniques in benign vascular lesions and renal trauma.

Adult↗