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Biomedical subjects

G M Richter

Publications and source records attributed to G M Richter.

At least 19 recordsLinked to original sources
PubMed2007

[Case report: massive lower intestinal bleeding from ileal varices: treatment with transjugular intrahepatic portosystemic shunt (TIPSS)].

Acute gastrointestinal bleeding in patients with liver cirrhosis is associated with a high mortality. Ileal varices and collaterals from ectopic vessels are extremely rare, encountered in less than 5% of the cirrhotic patients. The diagnosis is frequently delayed because the regular diagnostic methods such as gastroscopy or colonoscopy are unsuccessful in accurate the source of bleeding in the majority of the cases. We report an unusual case of massive and uncontrollable lower intestinal bleeding from ileal varices with right ovarian vein anastomosis in a 56 year-old female patient with liver cirrhosis and previous history of abdominal and pelvic surgery. The accurate angiographic and computed tomography diagnosis allowed fast decompression of the portal venous system using a transjugular intrahepatic portosystemic shunt.

Acute Disease↗
PubMed2006

Transarterial embolization of primary and secondary tumors of the skeletal system.

Percutaneous transcatheteral embolizations of primary and secondary bone tumors are important minimal invasive angiographic interventions of the skeletal system. In most of the cases embolization is performed for preoperative devascularization or as a palliative measure to treat tumor-associated pain or other tumor bulk symptoms. The transarterial embolization of primary and secondary tumors of the skeletal system has been developed to a safe and very effective method. Indications, techniques, results and complications of this minimal invasive interventional therapy for treatment of primary and secondary bone tumors are described and discussed and compared with the newer literature and our own results.

Adult↗
PubMed2005

[Treatment of malignant biliary obstructions via the percutaneous approach].

This paper gives an overview of experience and success of percutaneous transhepatic interventions in malignant biliary obstruction. Even after exhaustion of surgical and endoscopic therapy options, the percutaneously inserted stents provide effective palliation. The palliative treatment of malignant jaundice using a stent is an established procedure in clinical practice, particularly whenever the endoscopic, transpapillary approach is not possible due to high obstructions or previous surgery. The technical success rate is very high (about 95-100%), and the complication rate is about 10-30%. Since the patency rate of stents is higher than that of plastic endoprostheses, their primary use is justified despite higher costs, provided the patients are adequately selected.

Drainage↗
PubMed2005

Surgical thrombectomy followed by intraoperative endovascular reconstruction for symptomatic ilio-femoral venous thrombosis.

OBJECTIVES: To evaluate the efficacy of surgical thrombectomy combined with endovascular reconstruction for acute ilio-femoral/caval venous thrombosis. METHODS: Twenty consecutive patients with acute, symptomatic ilio-femoral/-caval thrombosis underwent valve-preserving thrombectomy with immediate endovascular repair between October 1996 and October 2003. Thrombectomy was classified by intraoperative venography as: TYPE I=complete, TYPE II=partial, TYPE III=complete with stenosis other than thrombus, TYPE IV=permanent occlusion. TYPEs I and IV were excluded from this analysis because endovascular repair was not performed. RESULTS: Left-sided venous thrombosis predominated (90%). Lesions were located in the common iliac vein (85%), the external iliac vein (10%), and the inferior vena cava (5%). Three TYPE II lesions and 17 TYPE III lesions (11 spurs, one hypoplasia, one fibrosis, one haematoma, and three others) were diagnosed. Catheter-directed recanalisation (thrombectomy/thrombolysis) resolved TYPE II lesions in three patients. Balloon angioplasty (one patient), iliac stenting (15 patients [two with thrombolysis]), and caval stenting (one patient) were employed in TYPE III stenoses. No serious complication or death occurred. Mean follow-up was 21 months. Of 20 patients clinical results were excellent in 18 patients who maintained patency of their reconstructed iliac veins. Primary and secondary patency rates were 80 and 90%, respectively. CONCLUSIONS: Ilio-caval venous obstructions detected intraoperatively can be reconstructed in a one-stage combined procedure. The specific endovascular approach depends on the type of residual venous obstruction. Excellent mid-term results indicate that the proposed thrombectomy classification (TYPE I-IV) and treatment algorithm optimises the results in selected patients with symptomatic venous thrombosis.

Adolescent↗
PubMed2005

[The role of 3-D imaging and computer-based postprocessing for surgery of the liver and pancreas].

Cross-sectional imaging based on navigation and virtual reality planning tools are well-established in the surgical routine in orthopedic surgery and neurosurgery. In various procedures, they have achieved a significant clinical relevance and efficacy and have enhanced the discipline's resection capabilities. In abdominal surgery, however, these tools have gained little attraction so far. Even with the advantage of fast and high resolution cross-sectional liver and pancreas imaging, it remains unclear whether 3D planning and interactive planning tools might increase precision and safety of liver and pancreas surgery. The inability to simply transfer the methodology from orthopedic or neurosurgery is mainly a result of intraoperative organ movements and shifting and corresponding technical difficulties in the on-line applicability of presurgical cross sectional imaging data. For the interactive planning of liver surgery, three systems partly exist in daily routine: HepaVision2 (MeVis GmbH, Bremen), LiverLive (Navidez Ltd, Slovenia) and OrgaNicer (German Cancer Research Center, Heidelberg). All these systems have realized a half- or full-automatic liver-segmentation procedure to visualize liver segments, vessel trees, resected volumes or critical residual organ volumes, either for preoperative planning or intraoperative visualization. Acquisition of data is mainly based on computed tomography. Three-dimensional navigation for intraoperative surgical guidance with ultrasound is part of the clinical testing. There are only few reports about the transfer of the visualization of the pancreas, probably caused by the difficulties with the segmentation routine due to inflammation or organ-exceeding tumor growth. With this paper, we like to evaluate and demonstrate the present status of software planning tools and pathways for future pre- and intraoperative resection planning in liver and pancreas surgery.

Hepatectomy↗
PubMed2004

[PTA versus Palmaz stent placement in femoropopliteal artery stenoses: results of a multicenter prospective randomized study (REFSA)].

PURPOSE: To evaluate whether stent placement is superior to percutaneous transluminal angioplasty (PTA) in the treatment of chronic symptoms in short femoropopliteal arterial stenoses. MATERIALS AND METHODS: One hundred twenty-four limbs in 116 patients, who ranged in age from 39 to 87 years (mean age, 67 years), were randomized to PTA (n = 53) versus PTA followed by implantation of long-medium Palmaz-Stents (n = 71). Inclusion criteria were intermittent claudication or chronic critical limb ischemia, short stenosis or occlusion (lesion length < or = 5 cm), and at least one patent run-off vessel at angiography. The follow-up included clinical assessment, measurement of ankle/brachial index (ABI), color duplex ultrasound, and/or angiography at 6, 12 and 24 months. Angiographic follow-up between 12 and 36 months was available in 54 limbs (45 %). RESULTS: Initial technical success was achieved in 50 of 53 limbs (94.4 %) in the PTA group versus 70 of 71 limbs (98.6 %) in the stent group. Overall, major complications occurred in 9.5 % (n = 11), with n = 4 in the PTA group compared to n = 7 in the stent group. No difference was found between the groups of treatment: clinical success at 1 and 2 years was 80.5 and 77.1 % in the PTA group versus 78.1 and 71.0 % in the stent group. The cumulative 1-year and 2-year angiographic primary patency rates were 66.1 and 49.1 % in the stent group versus 76.1 and 66.1 % in the PTA group. The secondary 1-year and 2-year angiographic patency rates were 88.5 and 53.3 % in the stent group versus 82.7 % and 76.2 % in the PTA group. CONCLUSION: The primary success rate was slightly higher after stent placement than after PTA. However, the angiographic, clinical and hemodynamic success after 1 and 2 years tends to be slightly better for PTA.

Adult↗
PubMed2004

[Uterine fibroid embolization with spheric micro-particles using flow guiding: safety, technical success and clinical results].

PURPOSE: To evaluate safety and mid term efficacy (> or = 1 year follow-up) of uterine fibroid embolization (UFE) using spherical particles (Embosphere) in a study applying criteria identical to those submitted to the FDA for initial material approval. MATERIALS AND METHODS: Twenty of the first 26 consecutive patients referred for potential UFE were enrolled in the study. Pre-interventional MRI was used to assess morphologic contraindication to UFE. The embolization procedures were performed from a unilateral femoral approach using 4F selective catheters in straight vessels, > 2 mm in diameter, and micro-catheters in smaller and tortuous arteries. The endpoint of the "flow guided" embolization was defined by reaching the angiographic "pruned tree" appearance and sluggish flow in the main stem of the uterine artery. Assessment of morphologic mid term success was done by MRI 10 days, 3 months, 6 months, 9 months and 1 year after UFE. The clinical mid term success was assessed by having questionnaires completed for menstrual bleeding, retention of clinical (symptomatic) benefit and quality of life. RESULTS: Technical success was 100 %, with 8 minor (2 post-interventional collapses, 2 hematomas, 4 relevant post-embolizations syndromes, 1 spontaneous expulsion of a submucous myoma) and 3 major complications (1 hysterectomy because of vaginal bleeding for 5 weeks, 1 transient amenorrhea and 1 spontaneous expulsion of myoma with transient bleeding requiring admission). In 17 of 19 patients, MRI showed total fibroid devascularization throughout the entire follow-up. The average shrinkage of the dominant fibroid was 71.3 % at one year. The menstrual bleeding record in the cohort group fell from an average of 501.6 before treatment to 76.2 points at one year. At the same time, the clinical symptoms significantly improved. The patient satisfaction with the applied therapy was > 95 % at 1 year. One patient with residual fibroid perfusion underwent a second procedure, which achieved complete devascularization and adequate clinical success at one year. The second patient with incomplete devascularization had a persistent clinical benefit. CONCLUSION: Under controlled study conditions, flow guided UFE with spherical particles achieves high overall success and patient satisfaction. MRI provides exact morphologic description of the fibroid for the initial evaluation and for post-procedural follow-up.

Adult↗
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↗
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↗
PubMed2003

[Risk and complication rate of uterine fibroid embolization (UFE)].

AIM: Our goal was to evaluate risks and complication rate of uterine fibroid embolization (UFE). RESULTS: The most frequent complications reported in the literature are associated with angiography procedure, serious complications are extremely infrequent. CONCLUSION: The embolization of fibroids is a safe angiographic intervention. Nevertheless, the interventional radiologist must be aware of the common risks and complication and the strategies to avoid them.

Embolization, Therapeutic↗
PubMed2002

Restoration of liver function and portosystemic pressure gradient after TIPSS and late TIPSS occlusion.

TIPSS (transjugular intrahepatic portosystemic shunt) may be indicated to control bleeding from esophageal and gastric varicose veins, to reduce ascites, and to treat patients with Budd-Chiari syndrome and veno-occlusive disease. Numerous measures to improve the safety and methodology of the procedure have helped to increase the technical and clinical success. Follow-up of TIPSS patients has revealed shunt stenosis to occur more often in patients with preserved liver function (Child A, Child B). In addition, the extent of liver cirrhosis is the main factor that determines prognosis in the long term. Little is known about the effects of TIPSS with respect to portosystemic hemodynamics. This report deals with a cirrhotic patient who stopped drinking 7 months prior to admission. He received TIPSS to control ascites and recurrent esophageal bleeding. Two years later remarkable hypertrophy of the left liver lobe and shunt occlusion was observed. The portosystemic pressure gradient dropped from 24 mmHg before TIPSS to 11 mmHg and remained stable after shunt occlusion. The Child's B cirrhosis prior to TIPSS turned into Child's A cirrhosis and remained stable during the follow-up period of 32 months. This indicates that liver function of TIPSS patients may recover due to hypertrophy of the remaining non-cirrhotic liver tissue. In addition the hepatic hemodynamics may return to normal. In conclusion, TIPSS cannot cure cirrhosis but its progress may be halted if the cause can be removed. This may result in a normal portosystemic gradient, leading consequently to shunt occlusion.

Adult↗
PubMed2002

[CT staging of malignant lymphoma. How to avoid misinterpretations].

Therapeutic strategy and prognosis of malignant lymphoma are influenced by staging. Therefore, evaluation of pattern of lymphatic involvement is highly relevant. There are numerous pitfalls possible in detection and description when malignant lymphomas are visualized by computed tomography (CT). Normal anatomic structures may be interpreted as pathologic lymph nodes by inexperienced radiologists. Assessment and detection of lymphomas require precise knowledge of normal anatomic structures as well as roentgenological criteria and adequate methods of imaging. This report provides an overview of the relevant pitfalls and often overlooked areas in staging of malignant lymphomas.

Diagnosis, Differential↗
PubMed2002

[Value of CT-guided biopsy in malignant lymphoma].

Management of diagnosing malignant lymphomas has changed with development of CT-guided techniques and reliable biopsy tools. Pathologists can use representative tissue samples for sub classification in more than 90%. Evaluation of residual lymphoma or relapse can be nearly as effective. Therefore percutaneous biopsy can be considered as primary diagnostic tool in the absence of peripheral lymphadenopathy. CT-guided biopsies can be performed on an outpatient basis under conscious sedation considering contraindications as well as regional complications. Acceptance of percutaneous biopsy by the pathologist and oncologist is based on diagnostic effectiveness that is significantly improved if more than 3 dagger solid tissue samples are taken. This article reviews the value of CT-guided biopsy in comparison to surgical procedures in patients with malignant lymphoma. Essential aspects that lead to a diagnostic percutaneous biopsy are discussed on grounds of the current literature.

Ambulatory Surgical Procedures↗
PubMed2002

Endoscopic variceal ligation plus propranolol vs. transjugular intrahepatic portosystemic stent shunt: a long-term randomized trial.

BACKGROUND AND STUDY AIMS: After a first variceal bleeding episode in patients with cirrhosis of the liver, treatment with transjugular intrahepatic portosystemic stent shunt (TIPS) and endoscopic variceal ligation (EVL) plus propranolol were compared, with regard to prevention of variceal rebleeding, complications, and mortality. PATIENTS AND METHODS: 85 patients were randomly allocated to receive TIPS (n = 43) or EVL (n = 42). The groups were comparable regarding age, sex, etiology of liver cirrhosis, and liver function. RESULTS: The mean observation times were 4.1 years in the TIPS group and 3.6 years in the EVL group. Although the probability of rebleeding was higher in the EVL group (29.9%) than in the TIPS group (19.4%), the difference was not statistically significant. Three of five patients of the EVL group successfully underwent TIPS placement after treatment failure. The probability of TIPS dysfunction requiring shunt revision was 89 %. Hepatic encephalopathy was observed more often in the TIPS group (40.5%) than in the EVL group (20.5%; P < 0.05). The probability of survival was similar in both groups (TIPS group 75.9%, EVL group 82.2%; n.s.). CONCLUSIONS: In view of its good efficacy and the lower cost of treatment, endoscopic ligation plus propranolol may be recommended as initial procedure for prevention of recurrent variceal hemorrhage, whereas TIPS seems to be the preferable procedure in patients with recurrent bleeding after adequate endoscopic and pharmacological treatment.

Adrenergic beta-Antagonists↗
PubMed2001

Neutrophils employ the myeloperoxidase system to generate antimicrobial brominating and chlorinating oxidants during sepsis.

The myeloperoxidase system of neutrophils uses hydrogen peroxide and chloride to generate hypochlorous acid, a potent bactericidal oxidant in vitro. In a mouse model of polymicrobial sepsis, we observed that mice deficient in myeloperoxidase were more likely than wild-type mice to die from infection. Mass spectrometric analysis of peritoneal inflammatory fluid from septic wild-type mice detected elevated concentrations of 3-chlorotyrosine, a characteristic end product of the myeloperoxidase system. Levels of 3-chlorotyrosine did not rise in the septic myeloperoxidase-deficient mice. Thus, myeloperoxidase seems to protect against sepsis in vivo by producing halogenating species. Surprisingly, levels of 3-bromotyrosine also were elevated in peritoneal fluid from septic wild-type mice and were markedly reduced in peritoneal fluid from septic myeloperoxidase-deficient mice. Furthermore, physiologic concentrations of bromide modulated the bactericidal effects of myeloperoxidase in vitro. It seems, therefore, that myeloperoxidase can use bromide as well as chloride to produce oxidants in vivo, even though the extracellular concentration of bromide is at least 1,000-fold lower than that of chloride. Thus, myeloperoxidase plays an important role in host defense against bacterial pathogens, and bromide might be a previously unsuspected component of this system.

Animals↗
PubMed2001

[Radiologic after-care of transjugular intrahepatic stent shunt (TIPSS)]].

The transjugular intrahepatic stent-shunt (TIPSS) is a well accepted minimal invasive therapy for complications of portal hypertension: recurrent variceal bleeding, refractory ascites and liver failure due to the Budd-Chiari syndrome. The high frequency of shunt stenoses and occlusions makes regular follow up examinations essential. Despite modern non invasive imaging methods direct portography still is the gold standard for shunt surveillance in TIPSS. Ultrasound is helpful to detect shunt dysfunction, but nevertheless its failure rate is considerable despite the use of contrast enhancers such as Levovist because of anatomic and physical limitations, particularly when TIPSS-tracts deep in the liver are present. Reintervention rates approach 90-100% after 24 months, with 100% in child's A patients with comparatively good liver function. However, a strict shunt surveillance program with early portography and reintervention when necessary guarantees high clinical success rates associated with very low rebleeding rates below 10%. Overall the secondary success rate is 80%. Secondary failures are mainly caused by lack of patient compliance during follow-up. In a subgroup of patients no shunt maturation is observed, requiring multiple shunt revisions. In cases of recurrent shunt occlusions an association with bile leaks is presumed. In selected cases patients with chronically recurrent shunt stenosis or occlusions may benefit from placement of TIPSS stent grafts.

Aftercare↗
PubMed2001

[The vascular patient--diagnosis and minimally invasive therapy. Which technique for what illness?].

The non-invasive imaging modalities, color coded duplex sonography (CCDS), magnetic resonance tomography (MRT), and computed tomography (CT), have pushed conventional angiography out of most diagnostic fields. The experienced user will achieve fast, reliable answers with CCDS in dedicated clinical settings. MRT as well as CT are concurring imaging modalities for the most appropriate diagnostic answer. Not only pure image quality, but also patient management, and availability play a major role. Catheter based angiography will in the future still play a role in mesenteric ischemia (non occlusive disease) and for imaging of very small vessel pathology, e.g. on panarteritis nodosa. At the moment, peripheral leg run-offs are still best performed with conventional angiography, nevertheless, MR as well as CT seem to have the ability to perform diagnostic procedures. Ongoing studies will allow a solid judgement in the near future. The true value of catheter angiography is in the direct assessment, planning, and performance of interventional procedures, e.g. catheter based obliteration or revascularization. Implantation of stent devices and a whole range of different mechanical and pharmacological revascularization procedures have improved the interventional management of vascular stenoses and occlusions. The interventional radiologist is treating physician in the classical sense in this setting. Acute bleeding episodes, e.g. in the brain, thorax, abdomen, or pelvis, are best imaged with computed tomography. Conventional angiography still plays a major diagnostic and therapeutic role in bleeding into preformed cavities, such as the bile ducts or the intestine. In this setting, all available information including CT scans should be valued. For complex therapeutic regimens in oncology or in pure palliative situations, angiographic diagnosis followed by embolization and/or ablation therapy is established.

Angioplasty, Balloon↗