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K J Pfeifer

Publications and source records attributed to K J Pfeifer.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Introduction of a new mobile C-arm/CT combination equipment (ISO-C-3D). Initial results of 3-D sectional imaging].

Preclinical evaluation of a new mobile C-arm image amplifier with an option for three-dimensional computed tomography (CT) imaging (prototype Iso-C3D) with respect to high-contrast resolution and possible clinical applications. Cadaveric specimens (n = 30) of different joints of the lower and upper extremities and specimens of the spinal column were examined with the Iso-C3D and evaluated for image quality. In addition, using a high-contrast phantom (Catphan, Phantom Laboratory, Salem, N.Y., USA) and a fracture model of the femoral bone, measurements of high-contrast resolution were performed in comparison to spiral CT. With the exception of the shoulder, all joint regions including the entire spinal column could be examined. Adequate image quality could be achieved in smaller joints such as the wrist, elbow, ankle, and knee, whereas a remarkably decreased image quality was found when imaging the hip as well as the lumbar and thoracic spine. Images of the phantom study and high-contrast fracture model showed a high-contrast resolution comparable to helical CT (9 Lp/cm in xy-axis). In smaller joints, the image quality of the mobile C-arm CT imaging system (Iso-C3D) is comparable to that of helical CT. Image quality in examinations of the hip and lumbar and thoracic spine seems to be sufficient for intraoperative control studies of osteosynthesis. Problems still occur in shoulder examinations.

Arthrography↗
PubMed2001

[3-D imaging with a mobile surgical image enhancement equipment (ISO-C-3D). Initial examples of fracture diagnosis of peripheral joints in comparison with spiral CT and conventional radiography].

To analyze a prototype mobile C-arm image amplifier (Iso-C3D) in the evaluation of different joint fractures of the upper and lower limbs using multiplanar reconstruction (MPR). Different cadaver joint specimens (n = 14) were examined with a prototype (Iso-C3D, Siemens AG, Erlangen, Germany), plain radiographs (CR), and spiral computed tomography (CT). The motorized C-arm provides fluoroscopic images during a 190 degrees orbital rotation computing a 119-mm data cube. These three-dimensional data sets yielded MPR images, which were evaluated by two readers for the detection and extent of fracture lines. Initial data show that fractures were easily depicted and correctly classified on MPR images with the Iso-C3D and that there was no difference between the Iso-C and CT in the detection of fractures. The preliminary results suggest a remarkably good detection of joint fractures with the Iso-C3D. Studies in an adequate number of patients are required to elucidate whether these promising results can also be obtained in a clinical setting.

Ankle Injuries↗
PubMed2001

[Comparative study of the quality of C-arm based 3D imaging of the talus].

Malposition of extraosseous or intra-articular screws, e.g., in osteosyntheses of joint fractures or in the vicinity of joints, frequently remains undiscovered in intraoperative fluoroscopy and is only recognized on postoperative computed tomography (CT) scans. The aim of the study, therefore, was to assess the value of a new mobile C-arm three-dimensional imaging device in comparison with fluoroscopy, conventional radiographs, and CT scans using an extremity model. Screws were inserted ventrally in four anatomic lower leg specimens without talus fractures parallel to the longitudinal axis to simulate surgical management of fractures of the talus. The specimens supplied were examined with fluorscopy, conventional radiography, spiral CT, and the new three-dimensional imaging with the SIREMOBIL Iso-C3D. These four modalities were evaluated by ten radiologists and ten trauma surgeons and were compared regarding subjective image quality and position of the screws. The quality of information acquired with the SIREMOBIL Iso-C3D was equal to that of the CT examinations, although image quality was considered inferior to fluoroscopy, conventional radiography, and CT (p < 0.001). In contrast to the previous procedure with intraoperative fluoroscopy and subsequent postoperative X-ray control, the results obtained with the SIREMOBIL IsoC3D were superior. The SIREMOBIL Iso-C3D is useful for the intraoperative diagnosis of small joints with few artifacts producing osteosynthesis material, i.e., for recognizing the position of screws in the region of glenoid surfaces.

Bone Screws↗
PubMed2001

[Radiological diagnosis in polytrauma: interdisciplinary management].

The presence of a radiologist within the admitting area of an emergency department and his capability as a member of the trauma team have a major impact on the role of diagnostic radiology in trauma care. The knowledge of clinical decision criteria, algorithms, and standards of patient care are essential for the acceptance within a trauma team. We present an interdisciplinary management concept of diagnostic radiology for trauma patients, which comprises basic diagnosis, organ diagnosis, radiological ABC, and algorithms of early clinical care. It is the result of a prospective study comprising over 2000 documented multiple injured patients. The radiologist on a trauma team should support trauma surgery and anesthesia in diagnostic and clinical work-up. The radiological ABC provides a structured approach for diagnostic imaging in all steps of the early clinical care of the multiple injured patient. Radiological ABC requires a reevaluation in cases of equivocal findings or difficulties in the clinical course. Direct communication of radiological findings with the trauma team enables quick clinical decisions. In addition, the radiologist can priority-oriented influence the therapy by using interventional procedures. The clinical radiologist is an active member of the interdisciplinary trauma team, not only providing diagnostic imaging but also participating in clinical decisions.

Diagnostic Imaging↗
PubMed2001

[Evaluation of spine boards for X-Ray diagnostics].

PURPOSE: Spine boards are frequently used in preclinical emergency care. Different models were examined with regard to their feasibility for plain film radiography and computed tomography (CT). METHODS: Five current spine board models were measured for their dimensions and weight. Transmission of radiation [microGyls] and dose area product [cGy x cm(2)] were determined with a patient equivalent aluminium phantom. Image artifacts, image quality and resolution of anatomic details were evaluated with an anthropomorphic Alderson phantom. RESULTS: With only 6.3 kg new models show a 28 % reduction in weight, three spine boards generate lateral artifacts due to a narrow width of 41 - 42 cm. Radiation transmission of all boards was similar, however dose area products differed by up to 59 %. Image quality was impaired in 4 out of 5 boards because of image artifacts, CT scanning was not impaired with all boards. CONCLUSION: Only one board (Ferno Millenia(R)) showed sufficient properties for plain film radiography and CT. There is no suitable spine board for preclinical and clinical applications as well as for trauma radiology, further improvements of current designs are essential.

Artifacts↗
PubMed2001

Elevated serum levels of S-100B reflect the extent of brain injury in alcohol intoxicated patients after mild head trauma.

Elevated systemic levels of S-100B are proposed as a potential indicator of brain damage in identifying high-risk patients after mild head trauma (MHT). Although incidence of alcohol intoxication is high in these patients, the influence of alcohol intoxication on S-100B levels is unclear. Therefore, the aim of our study was to investigate serum concentrations of S-100B in intoxicated (group 1) and sober (group 2) patients after MHT in comparison with those of mild (group 3) or severely intoxicated (group 4) individuals without trauma. S-100B was significantly increased in MHT patients exhibiting posttraumatic lesions in initial cranial computed tomography scan. Alcohol intoxication did not elevate S-100B levels in group 3 or 4 subjects. Our data indicate for the first time that alcohol intoxication does not influence the diagnostic value of S-100B measurements in patients after MHT.

Alcohol Drinking↗
PubMed2001

Fiberoptic bronchoscopic balloon dilatation in malignant tracheobronchial disease: indications and results.

STUDY OBJECTIVES: Bronchoscopic balloon dilatation (BBD) has become a valuable tool in the treatment of benign tracheobronchial stenoses. The objective of this study was to assess indications for and results of fiberoptic BBD in treating malignant lesions. DESIGN: One hundred twenty-six balloon dilatation procedures were performed in 78 patients with predominantly bronchial carcinoma. BBD was only performed when alternative modes of local treatment (eg, laser therapy or stent implantation) were not indicated or were inappropriate. Indications were symptomatic stenoses of the tracheobronchial tree: dyspnea or stridor (52%), retention pneumonia (15%), atelectasis (10%), retention of secretions (21%), or lung abscess (2%). RESULTS: Fifty-five percent of all procedures consisted of dilatations of tracheal or bronchial lesions (group 1). In 22% of procedures, a stent was dilated (group 2). In 13%, BBD was used to facilitate stent placement (group 3), and in 10% to enable the correct positioning of irradiation probes for brachytherapy (group 4). In group 1 and group 2, 2 of 2 lung abscesses resolved, 5 of 8 atelectases resolved, and 11 of 12 retention pneumonias resolved. Dyspnea improved in only 12 of 32 patients. No abscess recurred. Two pneumonias and two atelectases reappeared due to restenosis. Stent implantation and brachytherapy procedures were facilitated in 90% of cases. In 52% of cases, BBD was supported by high-frequency jet ventilation. Complications consisted of one fatal hemoptysis caused by a lacerated pulmonary artery, and minor bleeding not necessitating specific therapy. CONCLUSIONS: Fiberoptic BBD is useful in the management of airway stents prior to and postimplantation, as well as in the placement of brachytherapy catheters. BBD is also successful in the resolution of poststenotic lung abscesses, retention pneumonias, and atelectases.

Adult↗
PubMed2000

High-dose-rate brachytherapy: dose escalation in three-dimensional miniorgans of the human bronchial wall.

PURPOSE: High-dose-rate (HDR) brachytherapy of human lung cancer is well established, however fractionation schemes and dosages are based mainly on experience. The aim of this investigation was to study the effects of different doses of HDR iridium-192 on normal human bronchial epithelium in three-dimensional miniorgans of the human bronchial wall. METHODS AND MATERIALS: Forty-eight biopsies from normal bronchi were cultivated for 14 days and exposed at random to different doses of HDR iridium 192 (0 Gy, 30 Gy, 45 Gy, 60 Gy, or 75 Gy). Cell viability was assessed immediately after irradiation, after 4 or 18 days by fluorescent staining, and cell damage of the culture was analyzed by light microscopy. Lactate dehydrogenase (LDH) was measured in the supernatant for 4 days. RESULTS: There was no histologically apparent tissue damage regardless of the irradiation dose. The number of nonvital cells increased in irradiated miniorgans depending on the dose used (p < 0. 05 at 75 Gy). This effect occurred early and was less pronounced with time. LDH measurements showed an increase only in the first 24 hours. CONCLUSIONS: Our results confirm that normal bronchial epithelium has a high tolerance to early epithelial damage by irradiation. This model of human bronchial miniorgans is useful for further studies of the effects of irradiation on human bronchi.

Brachytherapy↗
PubMed2000

Flexible bronchoscopy: a safe method for metal stent implantation in bronchial disease.

BACKGROUND: Endoscopic bronchoplastic procedures, such as metal stent implantation, are for safety reasons and mainly performed using rigid bronchoscopy. Major complications, such as bleeding and accidental airway occlusion, are thought to be better managed with the rigid device. An increasing number of pneumologists, however, use the flexible fiberscope for endobronchial stenting. METHODS: Sixty-five stent implantations were performed in 51 patients with flexible fiberoptic bronchoscopy. We implanted 27 Tantalum Strecker stents (Boston Scientific Co, Watertown, MA), 20 Nitinol Accuflex stents (Boston Scientific Co) and 18 Wallstents (Schneider, Zurich, Switzerland). Underlying conditions were malignant disease in 84% and benign bronchial collapse in 16%. Sites of implantation were the trachea (45%), the main bronchi (35%), and other locations (20%). In 47 cases the patients received intravenous sedation combined with high frequency jet ventilation, and in 18 cases the patients were treated with topical anesthesia alone. RESULTS: Mean examination time was 58.3 (standard deviation 29.1) minutes. Eighty percent of patients experienced immediate clinical improvement in respiratory symptoms. Spirometric parameters (forced expiratory volume in one second, peak expiratory flow rate, forced vital capacity) increased. Complications included hypertension (17%), hypotension (12%), hypoxia (5%), bronchospasm (4%), initial displacement of the prosthesis (11%), and diameter mismatch between stent and bronchus (5%). All complications were managed safely. Relevant bleeding or asphyxia during the procedure has not been observed. Late stent migration was observed in 12% of cases. There were 3 fatalities within 30 days of stent placement which, however, were not attributed to the implantation technique. CONCLUSIONS: Flexible fiberoptic bronchoscopy is a safe and suitable method to perform endobronchial metal stent implantation. Complications were rare and not serious. Initial misplacement of the prosthesis occurred in some cases and necessitated removal and replacement within the same procedure.

Adult↗
PubMed2000

[Angina abdominalis: duplex ultrasound diagnosis and percutaneous revascularization].

Intestinal ischemia is still a challenge for clinicians and requires a close interdisciplinary cooperation between internist, surgeon and radiologist. In the last years the diagnosis and therapy, classically invasive and surgical, was supplemented by duplex ultrasound and percutaneous techniques like angioplasty and stenting. A 56 year-old man from Greece presented with epigastric pain, which was intensified by food ingestion. These symptoms were caused by a stenosis of the superior mesenteric artery, which was diagnosed by duplex sonography and angiography. No blood flow was detected in the inferior mesenteric and the celiac artery. Occlusion of one internal carotid artery made the patient a poor candidate for surgery. Therefore an interventional approach was chosen. A good result was achieved by angioplasty and stent implantation. On the day after the intervention oral food intake was possible without any pain. 18 months after the intervention the patient was free of abdominal symptoms. Therapy of mesenteric ischemia by percutaneous angioplasty and stenting is published only in case-reports and small series. Therefore the indication is mainly restricted to patients with a high risk for a surgical intervention.

Abdominal Pain↗
PubMed2000

[A combined PACS and Internet information system in a university medical center].

PURPOSE: The Department of Radiology at the University Hospital Innenstadt Munich provides all clinical departments of a large university hospital with several radiology units at different locations. During the last four years all units have been fully digitalized with a stepwise installation of a PACS. The PACS also processes images from the Nuclear Medicine Department. METHODS: As image modalities, archive systems and review workstations, we use devices from multiple vendors, which are integrated into a consistent system using the DICOM standard. The hospital has developed its own RIS and an Internet information system, which provides access to all reports and images from radiology for all clinical departments inside the hospital. Additionally, other clinical information such as laboratory results or ECG examinations are available through the system. RESULTS: After one year of operation, the system succeeded in the clinical routine work as the primary source for radiological reports and images as well as for laboratory values. CONCLUSION: The advantages of digitalization were, besides reduction of film cost, especially optimizations of work flow with access to digital images from everywhere at any time.

Academic Medical Centers↗
PubMed1999

[Temporary balloon occlusion as therapy of uncontrollable arterial hemorrhage in multiple trauma patients].

PURPOSE: Presentation of temporary balloon occlusion as an interventional radiological method for managing hemorrhage in multiply injured patients with uncontrollable loss of blood. METHOD: Temporary, non-selective arterial occlusion by introduction of a balloon catheter contralaterally to the source of bleeding has been performed since 1992 on 7 patients with multiple injuries, hemorrhagic shock requiring reanimation, and angiographic demonstration of an arterial hemorrhage in the supply region of the internal iliac artery with complex pelvic fracture. In each case a PTA balloon catheter was introduced transfemorally, non-selectively positioned proximal to the bleeding source, and left in place for 24-48 h under manometric control. Control angiographies were performed prior to catheter removal. RESULTS: The bleeding was stopped immediately in all 7 patients. The hemodynamic stability made transport and thus further surgical management and/or a short-term treatment in the intensive-care station possible. Control angiographies confirmed that the bleeding had stopped in all patients. CONCLUSIONS: We recommend temporary balloon occlusion as a rapid and effective method for the management of bleeding in otherwise uncontrollable traumatic hemorrhages in the supply region of the internal iliac artery.

Adult↗
PubMed1999

Noninvasive diagnosis of emphysema. Aerosol morphometry and aerosol bolus dispersion in comparison to HRCT.

Aerosol-derived airway morphometry (ADAM) and aerosol bolus dispersion (ABD) test are altered in patients with emphysema. We examined the diagnostic power of these aerosol methods in comparison with the noninvasive "gold-standard" HRCT in 50 consecutive patients with various lung diseases. The severity of airflow limitation was mild to moderate in the group of patients without emphysema and moderate to severe in the group of patients with HRCT-confirmed emphysema (FEV(1), 78 +/- 23% pred versus 53 +/- 33% pred; p < 0. 001). Among all lung function parameters under consideration ADAM showed the highest sensitivity and specificity for separating patients with emphysema from those without emphysema (area under the operating characteristics curve: p(ROC), 0.92), followed by ABD (p(ROC), 0.90), a marker for ventilation inhomogeneities. In patients with HRCT-confirmed macroscopic emphysema, peripheral air-space dimensions (EAD) at a relative volumetric lung depth V(pr) of 0.20 measured by ADAM were 155% larger, and bolus dispersion (ABD) at a lung depth of V(p) 600 ml was 53% larger than those observed in patients with other lung diseases (EAD = 0.84 +/- 0.53 mm versus 0.33 +/- 0.10 mm, p < 0.0001; ABD = 706 +/- 154 cm(3) versus 462 +/- 109 cm(3); p < 0.0001). EAD showed a significant correlation with the HRCT visual score (r = 0.78, p = 0.01). ABD showed weak significant correlations with all HRCT parameters under consideration (visual score, pixel density, mean lung density) (r = 0.45 to 0.66; p < 0.05). ADAM and ABD are powerful tools for the noninvasive diagnosis of macroscopic emphysema.

Aerosols↗
PubMed1998

Improvement in the therapy of multiply injured patients by introduction of clinical management guidelines.

A trauma algorithm representing the guidelines for the management of emergency treatment of severe blunt trauma was implemented at our institution in 1994. By comparison of two prospectively recorded cohorts of multiply injured patients, the clinical efficacy of these guidelines was analysed. The algorithm cohort comprised 74 patients over the period January 1994 to June 1996, and the Control cohort 126 patients over the period April 1988 to December 1993. To evaluate procedural quality of early clinical trauma management, nine criteria were applied. After implementation of the algorithm there was an improvement in all parameters reflected by a significant reduction of missed injuries and important time savings. Mortality rates in the cohorts were calculated after subdivision into three groups (I-III) with moderate (ISS: 18-24), high (ISS: 25-49) and very high (ISS: 50-75) injury severity. All cohort subgroups were comparable with respect to ISS values, age, initial loss of consciousness (GCS) and shock rate. In all subgroups of the algorithm cohort mortality rates were reduced: group I: 0 versus 20 per cent (p < 0.05); group II: 8 versus 24 per cent (p < 0.05); group III: 40 versus 71 per cent. Improvements in both therapeutic process and outcome were observed after implementation of the trauma algorithm.

Adult↗