[Radiological knowledge management with the help of departmental wikis]. / Radiologisches Wissensmanagement mithilfe eines abteilungsinternen Wikis.

In times of RIS (radiology information system) and KIS (hospital information system) systems, patient-related data are at the radiologist's disposal at the push of a button. However, this is not the case for other important data. The increasing complexity of modern medicine demands that up-to-date information like protocols, SOPs (Standards of Practice), news and modifications are constantly accessible to all employees. This aspect of quality assurance becomes increasingly important in the context of certification. For such knowledge management purposes we have built a wiki in our department. Here we report our positive experiences with this technology.

[Imaging in intensive care]. / Bildgebende Verfahren in der Intensivmedizin.

The application of imaging methods in patients that are highly dependent on medical support is limited. Ultrasound has a prominent impact due to its flexibility, bedside availability, rapid results, and cost-effectiveness - especially in the assessment of cardiovascular and abdominal diseases. Ultrasound artifacts at the pleura-air interface play an emerging role in the diagnosis of thoracic disease. X-ray imaging is increasingly limited to the assessment of medical artifacts and the follow-up of pulmonary disorders. Daily routine chest X-rays should be abandoned. Multidetector computed tomography has evolved as the gold standard in the definitive diagnosis of many acute critical disorders despite the need for patient transportation. The application of magnetic resonance tomography is in contrast restricted to specific central nervous system diseases.

[Combination of radiological and nuclear medical imaging in animals: an overview about today's possibilities]. / Kombinierte radiologische und nuklearmedizinische Bildgebung in Tierexperimenten: Ein Uberblick über die aktuellen Möglichkeiten.

Molecular imaging of small animals has made considerable progress in the last years. Various research fields are interested in imaging small animals due to the lower numbers of animals per experiment. This has advantages with respect to financial, ethical and research aspects. Non-invasive imaging allows examination of one animal several times during the same experiment. This makes it possible to follow a pathological process in the same animal over time. However, the radiological methods used such as magnetic resonance imaging or computed tomography as well as the nuclear medicine methods such as single photon emission computed tomography or positron emission tomography suffer from disadvantages. Molecular aspects are limited in the radiological methods while anatomical localization is difficult in nuclear medicine. The fusion of these methods leads to additional information. This review shows today's possibilities with their advantages as well as disadvantages.

[Long-term results after balloon angioplasty of the crural artery]. / Langzeitergebnisse nach Ballonangioplastie kruraler Arterien.

PURPOSE: To evaluate the technical success rate, procedure-related complications, and clinical long-term results for patients who underwent infrapopliteal angioplasty. MATERIALS AND METHODS: We retrospectively evaluated all patients who underwent infrapopliteal angioplasty to treat critical chronic limb ischemia or severe claudication from 1/1997 to 12/1999. We excluded patients with acute (< 2 weeks) limb ischemia. Procedure-related data were prospectively documented in a database and analyzed with a focus on the technical success rate and procedure-related complications. In addition all clinical documents were analyzed, and a follow-up examination was performed or telephone interviews were conducted with patients, relatives and referring doctors for follow-up. The primary end points were the limb salvage rate and patient survival rate. The secondary end points included the complication rate, technical success rate, and walking distance. RESULTS: 112 patients with a mean age of 72 years (41 women, 71 men) underwent crural angioplasty on 121 limbs. Four patients suffered from severe claudication (Rutherford category 3) and all others had critical chronic limb ischemia (category 4 to 6). The complication rate was 2.7 %. The technical success rate was 92 %. The ankle brachial index increased from 0.59 to 0.88. The mean walking distance increased significantly from 52 +/- 66 to 284 +/- 346 meters at the time of follow-up. The limb salvage rate was 83.6 % after one year and 81.1 % after three years. The mean survival rate according to Kaplan-Meier was 79.4 %, 69.2 %, and 54.2 % at 1, 2, and 3 years, respectively. Patients with at least one patent run-off vessel after angioplasty had a significantly better limb salvage rate. Diabetes was not a risk factor for limb salvage. CONCLUSION: Infrapopliteal angioplasty shows a high technical success rate with an acceptable complication rate. The clinical long-term success seems favorable if a least one open run-off vessel was able to be achieved. However, the survival rate was limited by the co-morbidity in this patient group.

Aortic stentgraft movement detection using digital roentgen stereophotogrammetric analysis on plane film radiographs -- initial results of a phantom study.

PURPOSE: To evaluate the feasibility of aortic stentgraft micromovement detection using digital roentgen stereophotogrammetric analysis on plane film radiographs. MATERIAL AND METHODS: An aortic stentgraft used for demonstration purposes was marked with 10 tantalum markers of 0.8 mm in diameter. The stentgraft was placed on a Plexiglas phantom with 5 tantalum markers of 1 mm in diameter simulating a fixed segment needed for mathematical analysis. In a subsequent step, the stentgraft was placed onto an orthopaedic spine model to simulate in vivo conditions.in a next step. Two radiographs taken simultaneously from different angles were used for simulating different stentgraft movement, e. g. translation, angulation, aortic pulsation and migration in the spine model. Movement of the stentgraft markers was analysed using a commercially available digital RSA setup (UmRSA(R) 4.1, RSA Biomedical, Umea, Sweden). RESULTS: Our study shows the feasibility of measuring aortic stentgraft movement and changes in stentgraft shape in the submillimeter range using digital roentgen stereophotogrammetric analysis. Translation along the 3 cardinal axes, change in stentgraft shape, simulation of aortic pulsation and simulation of in vivo conditions could be described precisely. CONCLUSION: Aortic stentgraft movement detection using digital roentgen stereophotogrammetric analysis on plane film radiographs is a very promising, precise method.

Primary and transplanted ENU induced rat tumors in neurooncology.

In neurooncology transplanting, tumors can be used for many purposes e.g. to solve questions concerning the etiology and pathogenesis of such tumors or their management. Experimentally induced and transplanted tumors of the nervous system become reproducible in their morphology and growth parameters after about 12 subsequent intracerebral passages. During the period from the first to the 12th intracerebral generations, a simplification of the histology and a reduction of the induction times take place. Nowadays the growth behavior of such tumors can be followed by imaging methods such as MRI if specially adapted to small animals. Our results are based on the investigation of over 2350 experimentally induced tumors of the central and peripheral nervous system that were diagnosed according to the rules of human and rodent brain tumor classification and various subgroups of this sample, analyzed by electron microscopy, postmortal angiography and MRI.

Analysis of mice tumor models using dynamic MRI data and a dedicated software platform*.

PURPOSE: To implement a software platform (DynaVision) dedicated to analyze data from functional imaging of tumors with different mathematical approaches, and to test the software platform in pancreatic carcinoma xenografts in mice with severe combined immunodeficiency disease (SCID). MATERIALS AND METHODS: A software program was developed for extraction and visualization of tissue perfusion parameters from dynamic contrast-enhanced images. This includes regional parameter calculation from enhancement curves, parametric images (e. g., blood flow), animation, 3D visualization, two-compartment modeling, a mode for comparing different datasets (e. g., therapy monitoring), and motion correction. We analyzed xenograft tumors from two pancreatic carcinoma cell lines (BxPC3 and ASPC1) implanted in 14 SCID mice after injection of Gd-DTPA into the tail vein. These data were correlated with histopathological findings. RESULTS: Image analysis was completed in approximately 15 minutes per data set. The possibility of drawing and editing ROIs within the whole data set makes it easy to obtain quantitative data from the intensity-time curves. In one animal, motion artifacts reduced the image quality to a greater extent but data analysis was still possible after motion correction. Dynamic MRI of mice tumor models revealed a highly heterogeneous distribution of the contrast-enhancement curves and derived parameters, which correlated with differences in histopathology. ASPC1 tumors showed a more hypervascular type of curves with faster and higher signal enhancement rate (wash-in) and a faster signal decrease (wash-out). BXPC3 tumors showed a more hypovascular type with slower wash-in and wash-out. This correlated with the biological properties of the tumors. CONCLUSION: With the described software, it was possible to analyze tissue perfusion parameters in small xenograft tumor models in mice. Our data correlated with histopathological data, and the qualitative and quantitative perfusion parameters could distinguish two tumor entities with different growth characteristics.

[Embolization of pulmonary arteriovenous malformations with electrolytically detachable coils in patients with hereditary hemorrhagic telangiectasia]. / Embolisation pulmonaler arteriovenöser Malformationen bei hereditärer hämorrhagischer Teleangiektasie mittels elektrolytisch ablösbarer Spiralen.

BACKGROUND: Pulmonary arteriovenous malformations (PAVM) can be found in approximately 20 % to 35 % of patients with hereditary hemorrhagic telangiectasia (HHT). PAVM should be treated since they are a source of paradoxical embolization, potentially resulting in severe neurologic complications. The treatment of choice is the endovascular embolization with coils. PATIENTS AND METHODS: Seven patients with HHT underwent superselective embolization of PAVM detected during screening for PAVM. Four patients had a single PAVM and one patient 3, 4 and 5 PAVMs, respectively. Electrolytically detachable coils were used for embolization. In addition, coils with synthetic fibers were used during 6 embolizations for completion of embolization. RESULTS: Embolization was technically successful in all patients. Complete primary occlusion was achieved in all PAVM. No coil migration or occlusion of unaffected pulmonary arteries was observed. After embolization, one patient developed a small pleural effusion, which was treated symptomatically. CONCLUSION: As a minimally invasive procedure, superselective embolization is the treatment of choice in treating PAVM in patients with HHT. With the use of electrolytically detachable coils, the ideal coil size can be chosen and exact placement achieved without the risk of coil migration or occlusion of unaffected pulmonary arteries.

[Radiological diagnosis and treatment of acute limb ischemia]. / Radiologische Diagnostik und Therapie bei akuter Extremitätenischämie.

Acute limb ischemia is associated with significant morbidity and mortality, despite diagnostic and therapeutic advances. Threatened limbs require immediate imaging in order to determine the subsequent therapeutic procedures. Conventional angiography in the DSA technique still has advantages over CT and MR angiography. In acute arterial occlusions below the femoral bifurcation, endovascular treatment with intra-arterial local thrombolysis or percutaneous thrombectomy is an alternative to open vascular surgical procedures. The following article describes diagnostic and therapeutic strategies for acute limb threat induced by arterial occlusion.

Transarterial chemoembolization of advanced liver metastases of neuroendocrine tumors--a retrospective single-center analysis.

BACKGROUND: In neuroendocrine tumors, metastases are a negative prognostic factor for survival and quality of life. Transcatheter arterial chemoembolization (TACE) is thought to be an effective symptomatic and antiproliferative treatment in patients with otherwise progressive disease. METHODS: 62 chemoembolization procedures in 26 patients with progressive neuroendocrine tumors were reviewed. The underlying disease was carcinoid syndrome in 10, non-functional midgut tumor in 2, non-functional pancreatic tumor in 7, malignant insulinoma in 2 patients, non-functional tumor of the stomach in 1 and of unknown origin in 4 patients. Tumor burden of the liver was <25% in 3, 25-50% in 11, 50-75% in 6 and >75% in 6 patients. RESULTS: TACE was technically successful in 57 cases. Four patients developed minor and 5 major complications. The 30-day mortality rate was 7.7%. According to WHO criteria, 14 patients had no change in tumor burden, 2 had regression and 5 progress after chemoembolization. Patients with a tumor burden >75% of the liver did not benefit from TACE due to the development of major complications, whereas patients with low (<50%) tumor burden and high (>50%) lipiodol uptake showed a trend towards longer survival. Five-year survival time after diagnosis was 48%. Patients treated with octreotide and/or alpha-interferon had no benefit from chemoembolization with regard to their carcinoid syndrome. CONCLUSIONS: In this retrospective study, patients with low (<50%) tumor burden and high (>50%) lipiodol uptake responded better to TACE than end-stage patients.

[Treatment of malignant biliary occlusion by means of transhepatic percutaneous biliary drainage with insertion of metal stents--results of an 8-year follow-up and analysis of the prognostic parameters]. / Behandlung der malignen Gallenwegsstenose mittels perkutaner transhepatischer Metallendoprothesenimplantation: 8 Jahres-Ergebnisse und Analyse prognostischer Faktoren.

PURPOSE: To analyze outcome and predictive factors for patient survival and patency rates of unresectable malignant biliary obstruction treated with percutaneous transhepatic insertion of metal stents. MATERIALS AND METHODS: This is a retroslective analysis of 130 patients treated in one interventional radiological center with data collected from patient records and by telephone interviews. The procedure-related data had been prospectively documented in a computer data base. The Kaplan-Meier analysis was performed for univariate and multivariate comparison of survival and patency rates with the log-rank test used for different tumor types. Predictive factors for survival and 30-day mortality were analyzed by a stepwise logistic regression. RESULTS: Underlying causes of malignant biliary obstructions were cholangiocarcinoma in 50, pancreatic carcinoma in 29, liver metastases in 27, gallbladder carcinoma in 20, and other tumors in 4 patients. The technical success rate was 99 %, the complication rate 27 % and the 30-day mortality 11 %. Primary patency rates (406 days with a median of 207 days) did not differ significantly for different tumor types. The survival rates were significantly (p = 0.03 by log-rank test) better for patients with cholangiocarcinoma than for patients with pancreatic carcinoma and liver metastases. Multiple regression analysis revealed no predictive factor for patient survival and 30-day mortality. CONCLUSION: Percutaneous transhepatic insertion of metal biliary endoprostheses offers a good initial and long-term relief of jaundice caused by malignant biliary obstruction. Although survival rates for patients with cholangiocarcinoma are better than for other causes of malignant biliary obstruction, a clear predictive factor is lacking for patients undergoing palliative biliary stent insertion.

1-molar gadobutrol as a contrast agent for computed tomography: results from a comparative porcine study.

RATIONALE AND OBJECTIVES: To evaluate prospectively the efficacy of gadobutrol as contrast agent for computed tomography (CT) compared with iodinated contrast media in a porcine animal model. METHODS: In 8 domestic pigs (35 +/- 4 kg body weight [BW]), continuous spiral CTs of the chest and abdomen were performed using either 2 mmol/kg BW Gadovist 1.0 (1 mol/L gadobutrol) intravenously or Ultravist (300 mg I/mL iopromide) (slice 5 mm, table feed 7.5 mm, reconstruction increment 5 mm). One week later, the same animals were examined using the same protocol with the other contrast agent. In 2 additional animals, serial CTs were performed at the same level using gadobutrol or iopromide on day 1 and the alternate agent on day 8 inches order to determine contrast media kinetics, peak enhancement, and time enhancement-product in important vascular regions and parenchymal organs (abdominal aorta, inferior vena cava, liver, and renal parenchyma). Peak enhancement (net increase compared with nonenhanced baseline values) was measured in Hounsfield units (HU) in defined regions of interest. RESULTS: In vivo, the mean peak enhancement 5, 15, 30, and 120 seconds in the abdominal aorta after injection of 2 mL/kg BW gadobutrol and iopromide was 200 +/- 11, 224 +/- 10, 261 +/- 13, and 95 +/- 9 HU versus 232 +/- 10, 298 +/- 10, 152 +/- 11, and 123 +/- 10 HU, respectively. Differences in enhancement of vascular structures was statistically significant (P < 0.05) in carotid arteries (235 +/- 20 HU for gadobutrol and 264 +/- 19 HU for iopromide) and the aortic arch (261 +/- 14 HU for gadobutrol and 279 HU +/- 13 HU for iopromide). No statistical significance was seen in all other measured vascular structures and parenchymal organs. CONCLUSION: Contrast-enhanced CT with 1 mol/L gadobutrol in a dose of 2 mmol/kg BW resulted in an excellent vascular and parenchymal enhancement in most vascular regions and parenchymal organs similar to an equivalent volume of 300 mg/mL iodinated contrast media.

Rotational digital cholangiography (RDC) and 3D-cholangiography (3DC) for guidance of percutaneous biliary drainage procedures.

PURPOSE: To evaluate whether RDC and 3DC help clarifying anatomic details in biliary duct disease and is useful for guidance of drainage procedures. MATERIALS AND METHODS: RDC was conducted in 11 consecutive patients (8 male, 3 female, mean age 63 years). Nine patients underwent PTBD for malignant biliary duct stenosis, one patient because of ischemic stenosis after hepaticojejunostomy and one patient presented with an infected biloma. Images were obtained after initial bile duct puncture during single breath hold from 120 projection angles using a rotating C-arm. These images were immediately available and evaluated in order to facilitate the definitive drainage procedure. For additional 3D reconstruction, data were sent to a dedicated workstation and judged by a blinded observer. RESULTS: The availability of a rotating data set of images was judged to be helpful in three patients with complex anatomical situations. Additionally, RDC holds the potential to reduce fluoroscopy time. 3DC allowed analysis of the hepatic bifurcation from different viewing angles in 10 cases with high spatial resolution (mean voxel size 480 micro micro m 3). This may allow a better classification of hilar obstructions according to our preliminary observations. CONCLUSION: Images from RDC and 3DC are helpful in guiding PTBD procedures and for better diagnosis in selected patients with hilar biliary duct stenoses.

Magnetic resonance phase contrast velocity measurement for non-invasive follow up after percutaneous transluminal angioplasty.

BACKGROUND: The aim of this study was to evaluate magnetic resonance phase contrast velocimetry (MRVL) as a non-invasive follow up tool to assess restenosis after percutaneous transluminal angioplasty (PTA). PATIENTS AND METHODS: We prospectively investigated 51 consecutive patients who underwent PTA of the femoropopliteal region. MRVL was conducted prior, one day, six weeks, twelve weeks and 24 weeks after PTA using a circular polarized extremity coil and a gradient echo sequence (TR/TE 600/6 ms, flip angel 30 degrees, slice thickness 10 mm). Hemodynamic data, derived from the MR phase contrast sequence, allowed to calculate the degree of area stenosis of the lesion treated with PTA. These data were correlated with clinical hemodynamic parameters (ankle-brachial index and walking distance). RESULTS: The mean grade of area stenosis was 69% +/- 27% before PTA, 30% +/- 20% one day, 29% +/- 23% six weeks, 39% +/- 17% twelve weeks and 42% +/- 18% 24 weeks after PTA and correlated well with clinical data and the post angioplasty clinical course of the patients. CONCLUSIONS: Follow up measurements using MRVL are suitable to assess restenosis after PTA and allow quantifying the grade of recurrent stenosis as well as the hemodynamic consequences.

Multiplanar reconstructions and three-dimensional imaging (computed rotational osteography) of complex fractures by using a C-arm system: initial results.

With use of a calibrated angiographic C-arm system and a postprocessing workstation, the authors acquired volume data sets from two-dimensional digital projection images obtained during a C-arm rotation around the patient axis. Multiplanar reconstruction and three-dimensional images of complex fractures were reconstructed and compared with spiral computed tomographic studies in a cadaveric pig study and in eight patients. Computed rotational osteography provided high-resolution multiplanar reconstruction and three-dimensional images of complex fractures.

[A holder for standardized radiological detection of ulnar capsule-ligament lesions of the thumb base joint]. / Halteapparat zum standardisierten radiologischen Nachweis ulnarer Kapsel-Band-Läsionen am Daumengrundgelenk.

AIM OF THE STUDY: To evaluate the usefulness of a self-constructed holding device for standardized, investigator-independent radiodiagnostics for ulnar capsulo-ligamentous lesions of the thumb metacarpophalangeal joint compared to the uninjured side. MATERIAL AND METHODS: A holding device for stress roentgenograms was constructed. Normal abduction arcs were evaluated in 20 degrees flexion in 28 healthy volunteers. The investigator-dependent variance was assessed. The study group comprised 123 consecutive patients (68 male, 55 female, aged 7 to 68 years, mean age 30 years). RESULTS: The normal arc of abduction was calculated to be 12 degrees (range 3 degrees to 24 degrees), while the mean individual difference in side by side comparison in volunteers was 0.3 degree (SD 2.69 degrees, range 0 degree-8 degrees). A rupture was diagnosed in 47 patients; 41 were operated. The preoperative diagnoses confirmed correct in all operated patients. A difference of greater than 6 degrees is indicative of a rupture with a sensitivity of 66.7% and a specificity of 96.9%. CONCLUSIONS: In summary, the holding device is useful for the practical work. Individual differences of less than 4 degrees are negative, between 4 degrees and 7 degrees questionable positive, between 7 degrees and 12 degrees are positive and over 12 degrees proof indicator of a rupture of the ulnar collateral ligament of the thumb metacarpophalangeal joint.

[Molecular radiology. II: Molecular imaging]. / Molekulare Radiologie. Teil II: Molekulare Bildgebung.

The most important strategies for molecular imaging are presented. Processes can now be imaged in vitro and in vivo at the molecular level with the help of modern procedures such as SPECT, PET, MRI, and highly developed optical methods. The ability to view the expression of genes, the pharmacokinetics of gene therapy vectors, of therapeutic DNA, and of classical pharmacons in vivo opens up completely new perspectives for the research on, diagnosis of, and therapy for diseases. The current status of these developments are described, potential fields of use and possibilities for further development are outlined.

Comparative trial of local pharmacotherapy with L-arginine, r-hirudin, and molsidomine to reduce restenosis after balloon angioplasty of stenotic rabbit iliac arteries.

PURPOSE: To determine if local application of L-arginine, r-hirudin, or molsidomine significantly reduces restenosis after balloon angioplasty in stenotic rabbit iliac arteries. MATERIALS AND METHODS: Thirty-one male cholesterol-fed New Zealand white rabbits underwent balloon dilation of both common iliac arteries to induce arterial stenosis. Four weeks later, one stenotic iliac artery was simultaneously dilated and received local application of L-arginine (210 mg/mL, n = 7), r-hirudin (0.5 mg/mL, n = 8), or molsidomine (0.2 mg/mL, n = 8) with a channeled balloon catheter. On the contralateral side, 0.9% saline was injected as a control. In eight sham animals, saline was applied to one iliac artery and balloon dilation to only the contralateral artery. Six weeks after local treatment, vessels were harvested, and computerized morphometric and immunohistologic analyses were performed. RESULTS: Application of drugs resulted in a significant reduction of neointimal area as follows: 53% with L-arginine (1.01 mm(2) vs. 2.17 mm(2), P <.05), 43% with molsidomine (1.04 mm(2) vs. 1.89 mm(2), P <.05), and 20% with r-hirudin (1.79 mm(2) vs. 2.24 mm(2), P <.05). Infusion of saline led to a significant increase (50%, 1.21 mm(2) vs. 1.93 mm(2), P <.05) in neointimal area compared with balloon dilation alone. Immunohistologic findings showed a significant reduction of macrophages (5.0% vs. 10.2%, P <.05) and proliferating cells (6.2% vs. 10.6%, P <.05) in the neointima after local application of L-arginine. CONCLUSION: Reduction of neointimal area was significant for L-arginine and molsidomine but not for r-hirudin. Saline infusion caused significant arterial trauma, resulting in additional neointimal proliferation.

Prospective comparison of MR phase-contrast velocimetry with intravascular doppler US during infrainguinal artery angioplasty.

PURPOSE: To evaluate the accuracy of magnetic resonance (MR) velocimetry for quantitative assessment of stenosis in patients undergoing percutaneous transluminal angioplasty (PTA). MATERIALS AND METHODS: Thirty patients underwent PTA of the infrainguinal region. To assess hemodynamic parameters of lesions, MR phase-contrast velocimetry with a circular-polarized extremity receiver coil and a cardiac gated gradient echo sequence was conducted before and 1 day after PTA. Additionally, all lesions were examined by means of intravascular Doppler flow measurements (0.018-inch wire, 12 MHz). From these data, the degree of stenosis was calculated and a comparison of MR velocimetry with intravascular Doppler US was undertaken. RESULTS: Correlation between calculated grade of stenosis for MR velocimetry and intravascular Doppler US was good and significant (r = 0.74; P <.001). Calculated luminal stenosis grade were similar for both methods before PTA (intravascular Doppler US: 0.62 +/- 0.18, MR velocimetry: 0.54 +/- 0.19; P =.17 with paired Student t-test) and after PTA (0.25 +/- 0.23 and 0.3 +/- 0.2, respectively; P =.56). CONCLUSION: MR velocimetry results in reliable noninvasive in vivo flow measurements and allows accurate assessment of stenosis in a clinical setting.