Efficacy of pelvic artery embolisation for severe postpartum hemorrhage.

PURPOSE: The purpose of our study was to evaluate the outcome of selective pelvic arterial embolisation (PAE) in women with severe postpartum hemorrhage (PPH). METHODS: We performed a retrospective, controlled, single-center cohort study. A total of 16 consecutive women with PPH who underwent therapeutic PAE were included. As historical control group, we included 22 women with similar severity of PPH who were managed without PAE. Outcome measures included necessity of surgical interventions such as postpartum hysterectomy and laparotomy after vaginal delivery, the amount of red blood cell transfusions, and hematologic findings after the procedure. RESULTS: PAE was successful in stopping PPH and preserving the uterus in all 16 women in the study group. No woman in the PAE group required a postpartum hysterectomy, whereas postpartum hysterectomy was unavoidable in two women in the control group. Laparotomy after vaginal delivery was necessary in two women of the group without embolisation. Hematologic parameters after the treatment were better in the PAE group than in the control group, although these differences were only in part statistically significant. There were no unwarranted effects of PAE identifiable in the study group. CONCLUSION: This is the first controlled study assessing the efficacy of PAE for the treatment of PPH. Our data suggest that PAE is effective for the treatment of severe PPH. In view of the lack of complications and unwarranted effects, clinical use of PAE in severe PPH seems justified, particularly in view of the life-threatening condition and the potential to preserve fertility in affected patients. Further evidence from well-designed prospective randomized-controlled trials would be nevertheless desirable in the future.

Source-detector trajectory optimization in cone-beam computed tomography: a comprehensive review on today's state-of-the-art.

Cone-beam computed tomography (CBCT) imaging is becoming increasingly important for a wide range of applications such as image-guided surgery, image-guided radiation therapy as well as diagnostic imaging such as breast and orthopaedic imaging. The potential benefits of non-circular source-detector trajectories was recognized in early work to improve the completeness of CBCT sampling and extend the field of view (FOV). Another important feature of interventional imaging is that prior knowledge of patient anatomy such as a preoperative CBCT or prior CT is commonly available. This provides the opportunity to integrate such prior information into the image acquisition process by customized CBCT source-detector trajectories. Such customized trajectories can be designed in order to optimize task-specific imaging performance, providing intervention or patient-specific imaging settings. The recently developed robotic CBCT C-arms as well as novel multi-source CBCT imaging systems with additional degrees of freedom provide the possibility to largely expand the scanning geometries beyond the conventional circular source-detector trajectory. This recent development has inspired the research community to innovate enhanced image quality by modifying image geometry, as opposed to hardware or algorithms. The recently proposed techniques in this field facilitate image quality improvement, FOV extension, radiation dose reduction, metal artifact reduction as well as 3D imaging under kinematic constraints. Because of the great practical value and the increasing importance of CBCT imaging in image-guided therapy for clinical and preclinical applications as well as in industry, this paper focuses on the review and discussion of the available literature in the CBCT trajectory optimization field. To the best of our knowledge, this paper is the first study that provides an exhaustive literature review regarding customized CBCT algorithms and tries to update the community with the clarification of in-depth information on the current progress and future trends.

[Percutaneous liver biopsy. Overview of different techniques]. / Perkutane Leberbiopsie. Ubersicht über verschiedene Verfahren.

To classify a liver tumor, image-guided percutaneous biopsy of a liver lesion is indicated. Using ultrasound (US) to guide a biopsy needle into a liver lesion has been proven useful and safe. If a lesion cannot be seen on US or the access to a lesion has been complicated by its position, CT-guided biopsy can be performed. If a lesion cannot be delineated on US or CT, MR-guided biopsy is recommended. Using hepatospecific contrast agents, the time span to delineate tumor tissue can be prolonged. To differentiate diffuse liver disease, transvenous biopsy under fluoroscopic control can be performed if a percutaneous biopsy is contraindicated. In recent years fine-needle aspiration biopsy has been increasingly replaced by coaxial 14-20 G core biopsy, which is a safe and efficient technique to classify liver lesions and has a low complication rate.

Computer-assisted intra-operative magnetic resonance imaging monitoring of interstitial laser therapy in the brain: a case report.

Hardware and software for a customized system to use magnetic resonance imaging (MRI) to noninvasively monitor laser-induced interstitial thermal therapy of brain tumors are reported. An open-configuration interventional MRI unit was used to guide optical fiber placement and monitor the deposition of laser energy into the targeted lesion. T1-weighted fast spin echo and gradient echo images were used to monitor the laser tissue interaction. The images were transferred from the MRI scanner to a customized research workstation and were processed intraoperatively. Newly developed software enabled rapid (27-221 ms) availability of calculated images. A case report is given showing images which reveal the laser-tissue interaction. The system design is feasible for on-line monitoring of interstitial laser therapy. © 1998 Society of Photo-Optical Instrumentation Engineers.

Vegetable oil as an MR contrast agent for rectal applications.

The purpose of this study was to evaluate the feasibility of pure vegetable oil as an MR contrast agent for rectal applications. The hypothesis was that vegetable oil highlights the lumen of the rectum after rectal application as a positive contrast medium and offers additional contrast qualities using fat suppression techniques. Eleven MRI examinations were performed on 11 subjects (five healthy volunteers, all males, mean age 35 yr; and six patients, three males, three females, mean age 49 yr). Peanut oil, 200 ml, was applied rectally. In addition, 0.1 mmol/kg GD-DTPA was administered intravenously to the six patients only. Conventional T1-weighted SE sequences and T1-weighted SE images with fat suppression were obtained. Criteria for image evaluation were: overall image quality; uniformity of contrast distribution; chemical shift artifact; and delineation of the rectal wall. Side effects were assessed. There were no complaints reported by the 11 subjects. The image quality was sufficient in all studies. In all five of the volunteers and five of the six patients, the distribution of oil was uniform. Chemical shift artifacts did not deteriorate image quality. After rectal application of vegetable oil, the delineation of the rectal wall was sufficient with and without fat suppression techniques. Vegetable oil highlights the lumen of the rectum in MRI studies and offers additional contrast qualities with fat suppression techniques, acting as a positive as well as a negative contrast agent, depending on the chosen sequence.

Assessment of chronic constipation: colon transit time versus defecography.

OBJECTIVE: The aim of this study was to determine the value of radiological colon transit time (CTT) measurements in relation to defecography (DFG) in chronically constipated patients. MATERIALS AND METHODS: In 30 patients with chronic constipation, total and segmental CTT was determined using radiopaque markers. In all of these patients defecography (DFG) was obtained. The patients were divided into three groups: In group I, 11 patients were classified with idiopathic constipation based on low stool frequency, normal DFG, or absence of symptoms of abnormal defecation. In group II, ten patients with rectal intussusception were diagnosed by DFG. In group III, there were nine patients with rectal prolapse or spastic pelvic floor syndrome, based on results of DFG. RESULTS: Group I, idiopathic constipation (n = 11), showed increased total CTT (mean, 93 h) and segmental CTT (right colon, 33 h (36%), left colon, 31 h (33%), rectosigmoid, 29 h (31%)). In group II, intussusception (n = 10), patients had normal mean total CTT (54 h) and a relative decrease in rectosigmoid CTT (mean, 13 h (24%)). In group III (n =9), rectal prolapse (n = 5) or spastic pelvic floor syndrome (n = 4), patients showed elevated total (mean, 167 h) and rectosigmoidal CTT (mean, 95 h (57%)). Mean total CTT was significantly different between groups I and II and between groups II and III, and mean rectosigmoidal CTT was significantly different between all three groups (P < 0.05). CONCLUSION: The use of total and rectosigmoidal CTT helps to identify the underlying pathophysiology of chronic constipation. Furthermore CTT helps to identify patients, who may benefit from DFG.

[Three-dimensional digital rotation angiography for embolization therapy of uterine leiomyomas: first results]. / Dreidimensionale digitale Rotationsangiographie in der Embolisationstherapie von Uterusmyomen: Erste Erfahrungen.

PURPOSE: To evaluate three-dimensional rotational digital subtraction angiography (3D-RDSA) in the embolization of the uterine artery in the treatment of symptomatic uterine leiomyomas (fibroids). MATERIALS AND METHODS: Eight women with complex pelvic vessel anatomy caused by large fibroids were embolized using 3D-RDSA. The raw data were sent to an external workstation, and video files with a resolution of one image/3 degrees and a scan range of 180 degrees in a surface-shaded display mode were produced. The primary goal was to assess an image intensifier angulation for the optimal visualization of the origin of the uterine artery. In addition, the intervention parameters were compared with those of 48 patients with standard angiography. RESULTS: The analysis revealed no single angulation that can be recommended for standard angiography. No statistical differences were found between both groups concerning fluoroscopy time, dosage area product and amount of administered contrast medium (p > 0.05). CONCLUSION: It can be stated that 3D-RDSA is a feasible method that facilitates the catheterization of the uterine artery even in patients with complex pelvic vessel anatomy, with the potential to reduce the radiation exposure and the amount of administered contrast medium in future embolization therapy of symptomatic uterine fibroids.

[Evaluation system in assessing radiological examinations of clinical significance for the patient]. / Bewertungssystem zur Erfassung des Stellenwertes radiologischer Leistungen für die klinische Arbeit am Patienten.

PURPOSE: The purpose of this study was to test a scoring system and its utility for the assessment of the clinical significance of radiological examinations. MATERIAL AND METHODS: The reports of all diagnostic studies obtained in patients with a clinical suspicion of pancreatitis, urinary tract obstruction, biliary or gallbladder diseases, ileus and gastrointestinal perforation were scored prospectively in 4 categories from 0 to 3. These categories were related to the ability to establish a definite diagnosis, to exclude suspected disease, to influence further diagnostic work-up and therapeutic decision-making. RESULTS: This scoring system showed significant differences of the efficacy of different imaging modalities in these 5 clinical settings. CONCLUSION: This scoring system was helpful to determine the clinical significance of radiological examinations.

Computer-based imaging and interventional MRI: applications for neurosurgery.

Advances in computer technology and the development of open MRI systems definitely enhanced intraoperative image-guidance in neurosurgery. Based upon the integration of previously acquired and processed 3D information and the corresponding anatomy of the patient, this requires computerized image-processing methods (segmentation, registration, and display) and fast image integration techniques. Open MR systems equipped with instrument tracking systems, provide an interactive environment in which biopsies and minimally invasive interventions or open surgeries can be performed. Enhanced by the integration of multimodal imaging these techniques significantly improve the available treatment options and can change the prognosis for patients with surgically treatable diseases.

Salmon calcitonin and calcium in the treatment of male osteoporosis: the effect on bone mineral density.

OBJECTIVE: To assess the effectiveness of salmon calcitonin in the therapy of male osteoporosis. METHODS: Nine male patients aged 20-73 years with vertebral osteoporosis were included in this study. Patients were prescribed 100 units of salmon calcitonin injected subcutaneously three times per week over a period of three months, followed by three months without salmon calcitonin treatment. Thereafter the patients received another salmon calcitonin cycle for three months as described above. All men received calcium supplementation of 1000 mg/day throughout the study period of 12 months. Bone mineral density of the lumbar spine and at the hip was measured at the beginning and the end of the treatment period using DXA (n = 7) or QCT (n = 2). RESULTS: Baseline evaluation revealed a bone mineral density of the lumbar spine of 0.78 +/- 0.09 g/cm2 and 0.62 +/- 0.09 g/cm2 at the hip. Treatment with salmon calcitonin resulted in a significant increase of vertebral bone mineral density to 0.80 +/- 0.09 g/cm2 (p < 0.015). Femoral bone mineral density also significantly increased after salmon calcitonin therapy to 0.64 +/- 0.11 g/cm2 (p < 0.05). CONCLUSION: These results show that calcium and salmon calcitonin increase bone mineral density in male patients with osteoporosis. Calcium and calcitonin may be useful in the treatment of male osteoporosis; however, further studies are necessary before definite recommendations can be made.

Protective embolization of the gastroduodenal artery with a one-HydroCoil technique in radioembolization procedures.

PURPOSE: Protective occlusion of the gastroduodenal artery (GDA) is required to avoid severe adverse effects and complications in radioembolization procedures. Because of the expandable features of HydroCoils, our goal was to occlude the GDA with only one HydroCoil to provide particle reflux protection. METHODS: Twenty-three subjects with unresectable liver tumors, who were scheduled for protective occlusion of the GDA before radioembolization therapy, were included. The primary end point was to achieve a proximal occlusion of the GDA with only one detachable HydroCoil. Evaluated parameters were duration of deployment, and early (during the intervention) and late (7-21 days) occlusion rates of GDA. Secondary end points included complete duration of the intervention, amount of contrast medium used, fluoroscopy rates, and adverse effects. RESULTS: In all cases, the GDA was successfully occluded with only one HydroCoil. The selected diameter/length range was 4/10 mm in 2 patients, 4/15 mm in 6 patients, and 4/20 mm in 15 patients. HydroCoils were implanted, on average, 3.75 mm from the origin of the GDA (range 1.5-6.8 mm), with an average deployment time of 2:47 (median 2:42, range 2:30-3:07) min. In 21 (91%) of 23 patients, a complete occlusion of the GDA was achieved during the first 30 min after the coil implantation; however, in all patients, a late occlusion of the GDA was present after 6 to 29 days. No clinical or technical complications were reported. CONCLUSION: We demonstrated that occlusion of the GDA with a single HydroCoil is a safe procedure and successfully prevents extrahepatic embolization before radioembolization.

[PTA and stent placement distal to the superficial femoral artery]. / PTA und Stent distal der AFS.

Although angioplasty and stent applications in the iliac vessels and the superficial femoral artery have become routine procedures, their usefulness for the treatment of lesions of the popliteal artery and the lower leg arteries is still under discussion. For the popliteal artery, limitations are mainly due to the high mechanical stress in this area, causing high traction forces. Moreover, beyond the occlusive atherosclerotic changes, specific pathological entities such as aneurysms, emboli, entrapment syndromes, and cystic adventitial disease have to be differentiated. There is hope that the development of innovative stent designs with high flexibility might overcome the limitations. For lesions of the lower leg arteries treatment with percutaneous transluminal angioplasty (PTA) has become the method of choice. However, stent designs as used for cardiac interventions have been adapted for their application below the knee, and first encouraging results may help to justify their broad use in the future. Regarding PTA, innovative equipment and techniques for the treatment of arterial lesions below the knee include dedicated, long, and very flexible balloons, cutting balloon cryoplasty, and laser angioplasty. Regarding stents, bare metal stents, stents with passive or active coatings, and bioabsorbable stents have all been successfully used.

Treatment of an acute type B dissection with an intramural haematoma in the ascending aorta by percutaneous endovascular stent-graft placement.

Acute type B dissections accompanied by an intramural haematoma in the ascending aorta are rare. However, progression of the intramural haematoma in the ascending aorta poses risks for the patients, which are similar to those of type A dissections, including pericardial effusions and consecutive tamponade. To date, no clear treatment guidelines exist for these patients. We report on successful percutaneous endovascular stent-graft treatment of an acute type B dissection accompanied by an intramural haematoma in the ascending aorta as primary and sole form of treatment.

PTA versus carbofilm-coated stents in infrapopliteal arteries: pilot study.

PURPOSE: To determine the primary success and short-term patency of stent application as a primary treatment modality for high-grade lesions of the infrapopliteal arteries compared with treatment with percutaneous transluminal angioplasty (PTA) in critical limb ischemia in a randomized prospective study. METHODS: Endovascular therapy was performed on 95 lesions in 51 patients (mean age 72.0 years, range 47-80 years) who presented clinically with Fontaine stages III and IV. One patient underwent treatment in both limbs. After angiographic lesion identification, patients were randomized for treatment by PTA (53 lesions in 27 patients) or stent application (42 lesions in 24 patients). Follow-up by clinical investigation and conventional angiography or spiral CT angiography was performed in 37 patients (57 lesions) 6 to 12 months after the procedure, or when clinically indicated. Evaluation was performed by two observers, double-blinded, with thresholds for lesion restenosis of 50% and 70%. Statistical evaluation was performed on a lesion basis by Kaplan-Meier estimated probability rates, and log-rank and Wilcoxon tests. The primary endpoint was the angiographic patency rate of treated lesions. RESULTS: The inter-reader agreement was high (kappa = 0.82). For the stent group the cumulative primary patency at 6 months was 83.7% at the 70% restenosis threshold, and 79.7% at the 50% restenosis threshold. For PTA, the primary patency at 6 months was 61.1% at the 70% restenosis threshold and 45.6% at the 50% restenosis threshold. Both results were statistically significant (p < 0.05). CONCLUSION: Infrapopliteal stent application is an effective treatment modality for high-grade lesions in chronic critical limb ischemia. Compared with PTA, higher patency rates can be expected after 6 months.

Risk analysis and safety assessment in surgical robotics: a case study on a biopsy robot.

One of the most important issues in medical robotics is safety and integration into the clinical workflow. If a robot is not safe and its use is complicated by difficult handling and complex user interfaces physicians would not use a robotic system during clinical patient trials, whatever the other advantages are. However, there are only few publications on this topic, in particular on risk management in developing a robotic prototype (for clinical trials). In this paper risk management and the safety of using robot-assisted surgery equipment are discussed and demonstrated exemplarily in the process of developing a prototype biopsy robot.

[A comparison of sonography and phlebography in the diagnosis of deep venous thrombosis of the lower extremities]. / Vergleich der Sonographie mit der Phlebographie in der Diagnose der tiefen Beinvenenthrombose der unteren Extremität.

In recent years, non-invasive sonographic techniques [real-time ultrasound (US), duplex ultrasonography (DU) and color-coded duplex sonography (CCDS)] have increased in importance for the diagnosis of lower extremity deep venous thrombosis. To ascertain the accuracy and limitations of these techniques prospectively, various studies have been performed to compare sonography with venography. This review deals with basic methodologic considerations when two imaging methods are compared and describes the features of deep venous thrombosis seen on US, DU and CCDS. Reports comparing sonography and phlebography for the diagnosis of deep venous thrombosis are presented and discussed. The advantages and limitations of US, DU and CCDS for the diagnosis of iliac, femoral, popliteal and infrapopliteal venous thrombosis are compared with those of venography, and controversial areas are touched on.

Report generation using digital speech recognition in radiology.

The aim of this study was to evaluate whether the use of a digital continuous speech recognition (CSR) in the field of radiology could lead to relevant time savings in generating a report. A CSR system (SP6000, Philips, Eindhoven, The Netherlands) for German was used to transform fluently spoken sentences into text. Two radiologists dictated a total of 450 reports on five radiological topics. Two typists edited those reports by means of conventional typing using a text editor (WinWord 6.0, Microsoft, Redmond, Wash.) installed on an IBM-compatible personal computer (PC). The same reports were generated using the CSR system and the performance of both systems was then evaluated by comparing the time needed to generate the reports and the error rates of both systems. In addition, the error rate of the CSR system and the time needed to create the reports was evaluated. The mean error rate for the CSR system was 5.5%, and the mean error rate for conventional typing was 0.4%. Reports edited with the CSR, on average, were generated 19% faster compared with the conventional text-editing method. However, the amount of error rates and time savings were different and depended on topics, speakers, and typists. Using CSR the maximum time saving achieved was 28% for the topic sonography. The CSR system was never slower, under any circumstances, than conventional typing on a PC. When compared with a conventional manual typing method, the CSR system proved to be useful in a clinical setting and saved time in generating radiological reports. The amount of time saved, however, greatly depended on the performance of the typist, the speaker, and on stored vocabulary provided by the CSR system.

[Percutaneous radiofrequency ablation of liver cell carcinoma: a current overview]. / Perkutane Radiofrequenzablation von Leberzellkarzinomen: eine aktuelle Ubersicht.

In patients with hepatocellular carcinoma (HCC) surgical resection so far offers potential cure. Due to the frequent association with liver cirrhosis less then 30% of patients with HCC can be resected. In unresectable cases, radiofrequency ablation (RFA) offers an effective treatment alternative. Substantial improvements in the development of powerful generators (up to 250 W) combined with expandable, closed or open-perfused needle electrodes, provide coagulation necroses up to 5 cm in diameter. Most recently primary technical success rates of 85 to 100% were reported. Following RFA of HCC's (diameter up to 2,8 cm) 1-, 2-, 3 and 5-year survival was reported to be 97, 89, 71 and 48%. Low complication rates of 0-12% and a mortality of 0-1% indicate the minimal-invasive character of RFA. Basic principles, technique, indications, contraindications and limitations of percutaneous RFA will be discussed together with a presentation of own cases and a review of literature.