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Biomedical subjects

U Linsenmaier

Publications and source records attributed to U Linsenmaier.

At least 19 recordsLinked to original sources
PubMed2007

[Comparison of C-arm CT and standard imaging in osteosyntheses of fractured distal radius specimens].

BACKGROUND: The purpose of this study was to evaluate the value of C-arm CT imaging of the distal radius with standard patient positioning in intraoperative assessment of plate osteosynthesis. MATERIALS AND METHODS: Four complete distal radius specimens from human cadavers were fractured (type C), and internal fixation with palmar plates (stainless steel) was then carried out in each. On the basis of C-arm fluoroscopy, radiography and C-arm CT (Siremobil Iso-C3D, scans with forearm bones positioned parallel to the z-axis), 19 observers subsequently evaluated the positions of screws near the joint and any steps within the joint, after which the bones were surgically exposed and the imaging results checked against direct visual observations. RESULTS: No statistically significant differences were detected either between the modalities or between the evaluator groups. CONCLUSION: With standard patient positioning, the performance of C-arm CT was equivalent to and not better than that of current standard procedures, i.e. intraoperative fluoroscopy and postoperative radiography. Further studies should examine whether this holds true in clinical practice with representative patient collectives when titanium implants are used and/or optimized patient positioning is practised.

Cadaver↗
PubMed2006

Development of an accelerated MSCT protocol (Triage MSCT) for mass casualty incidents: comparison to MSCT for single-trauma patients.

During multiple casualty incidents (MCI) emergency radiology departments have to deal with a large number of patients with suspected severe trauma within a short period of time. The aim of this study was to develop a suitable accelerated multislice computed tomography (MSCT) protocol to increase patient throughput for this kind of emergency situation. We presumed a scenario of 15 patients being admitted to the trauma service with suspicion of severe injuries after a MCI over a period of 2 h. An accelerated Triage MSCT protocol was developed and evaluated for MSCT scanner productivity (patients per hour) and time (minutes) needed for a total MSCT body workup using an anthropomorphic phantom. In addition, time (minutes) for transfer and preparation was measured. These timeframes were compared to a control group consisting of 144 single patients with multiple trauma undergoing standard MSCT according to our trauma room protocol. All MSCT studies were conducted using a 4-detector row scanner. (1) For the study group (Triage MSCT), average time for patient transfer and preparation was 2.9 min (2.5-4.3 min), mean CT examination time was 2.1 min (1.7-2.4 min); image reconstruction took 4.0 min (3.3-4.3 min). Total time in scanner room was 8.9 min (7.7-11.3 min), resulting in a maximal productivity of 6.7 patients per hour. Image transfer to the digital picture archive and communication system archive was completed after an average 9.5 min (8.9-10.8 min). (2) For the control group (single casualty MSCT), the mean time for patient transfer and preparation was 20.4 min (9.0-39.2 min), mean examination time was 6.0 min (3.1-11.3 min). Times for image reconstructions were not recorded in the patient series. Mean total time in scanner room was 25.3 min (11.0-72.4 min), resulting in a patient throughput of 2.4 patients per hour. MSCT has potential to serve as a powerful tool in triage of multiple casualty patients. The introduction of a Triage MSCT scanning protocol resulted in an increase of patient throughput per hour by a factor of almost 3.

Clinical Protocols↗
PubMed2006

[CT-guided vertebroplasty and kyphoplasty: comparing technical success rate and complications in 101 cases].

PURPOSE: To compare the technical success and complication rates in CT-guided vertebroplasty and kyphoplasty. MATERIALS AND METHODS: From 2002 - 2005 69 patients (101 vertebrae) were treated with vertebroplasty (n = 82) or kyphoplasty (n = 19) using 4-slice MSCT with CT fluoroscopy as the sole guidance for the procedure. The underlying lesions were osteoporotic fractures in 78 vertebral bodies and 23 vertebral metastases. RESULTS: Technical success was achieved in all 101 procedures. Post-interventional CT demonstrated asymptomatic cement leakage in 51/101 vertebrae. Kyphoplasty resulted in leakage in 11/19 (57.9 %) and vertebroplasty in 40/82 (48.8 %) procedures. With p = 0.48 (Mann-Whitney Test) there was no significant difference between kyphoplasty and vertebroplasty with respect to the number of cement leakage occurrences. There was one minor complication of an L5 root irritation following radiofrequency ablation and vertebroplasty of a sarcoma metastasis which subsided without treatment after 8 weeks. There was one major complication of intraspinal cement leakage during tumor vertebroplasty causing T5 root compression and requiring laminectomy for cement removal. The overall rate of major complications requiring treatment was 0.99 %. CONCLUSION: Vertebroplasty and kyphoplasty can be safely performed using only MSCT fluoroscopy guidance. The rate of major complications is very low. There was a high rate of small asymptomatic cement leakages which may have remained undetected with conventional fluoroscopy (CF). There was no statistically significant advantage for kyphoplasty with respect to cement leakage and the technical success rate.

Adult↗
PubMed2005

[Radiological intervention in multiply injured patients].

The most frequent cause of mortality during the first 4 h following severe trauma is uncontrollable hemorrhage from large arteries and parenchymal organs, whereas traumatic injuries of the heart and aorta are responsible for sudden death occurring at the accident site. It is therefore mandatory to diagnose and treat these injuries rapidly. Multislice spiral computed tomography is a highly useful imaging modality for severely injured patients. In this group of patients, various interventional procedures such as embolisation, stenting and temporary balloon occlusion may contribute to saving lives. In ruptures of the aorta and major arteries, stenting and temporary balloon occlusion may prevent exsanguination. Transcatheter embolisation is useful in hemorrhage from visceral organs, arteriovenous fistulas and secondary onset hemorrhage.

Algorithms↗
PubMed2004

[Identification of high-risk patients after minor craniocerebral trauma. Measurement of nerve tissue protein S 100].

The indication for an initial cranial computed tomography (CCT) in minor head trauma (MHT) patients remains the subject of discussion. The aim of this study was to investigate whether a newly developed, rapid test system (ELECSYS S100, Roche Diagnostics) might allow a diagnostically valid, reproducible measurement of S 100 in MHT patients. Blood samples were drawn from 75 MHT patients, a CCT scan was performed, and those with a post-traumatic intracranial lesion counted as CCT+. Results were compared to a healthy control group (n=17). Of the 75 patients included in the study, 14 were stratified as CCT+. The systemic concentration of S 100 in these CCT+ patients was significantly increased (0.31 microg/l) compared to the healthy control group (0.04 microg/l) as well as to the CCT-negative patients (0.08 microg/l). The ELECSYS S100 system allows a rapid, valid, and reproducible assessment of S 100B in patient serum and this concentration is significantly elevated in patients suffering from intracranial lesions as shown by initial CCT scan. Hence, this study is the basis for a multicenter trial currently underway to confirm the results of our pilot study.

Adult↗
PubMed2004

[Priority-oriented shock trauma room management with the integration of multiple-view spiral computed tomography].

In major trauma it is essential to immediately recognize and treat life-threatening problems and conditions. Most trauma protocols reserve the use of computed tomography for the secondary survey, as patients cannot be attended to during the examination and must be transferred from the emergency room to the CT suite. The relevant reduction in the scanning time of multidetector computed tomography (MDCT) or multislice computed tomography (MSCT) justifies its use as the major diagnostic adjunct for primary trauma survey and initial resuscitation. According to our ATLS((R))-based trauma algorithm, the multidetector scanner situated in the emergency department is utilized immediately after the correction of respiratory problems to detect causes of bleeding or intracranial hematomas. In a prospective series a total of 125 consecutive major trauma patients were evaluated. After focused sonography in trauma (FAST) and plain chest films in intubated patients, whole body MDCT was performed. By retrieving data from our trauma registry and a picture archiving and communication system (PACS), time from trauma room admission to the end of head CT scan for the entire MDCT study and calculation of multiplanar reconstruction (MPR) was analyzed. Additionally, relevant complications such as untreated tension pneumothorax or circulatory arrest during MDCT examination were recorded. The time from admission to the trauma room until completion of head CT scan without contrast was 21:12 min (median, IQR 18:13-27:52). The entire contrast-enhanced MDCT study, including pilot scan and contrast application, required 6:08 min (median, IQR 4:33-8:14) with a total scanning time of 0:59 min (median, IQR 0:55-1:03). MPR calculation of the spine and bony pelvis was performed in 11:37 min (median, IQR 8:03-16:41). A relevant life-threatening complication due to CT scanning during primary trauma survey was not observed in the 125 cases (0/125 CI 95% 0%-3%). Complete diagnostic imaging can be performed within 30 min after trauma room admission by using MDCT. During the primary survey, treatment of the patient is interrupted just for the few minutes of the CT scan and contrast application. An adequate survey of injuries can be achieved earlier and a targeted therapy can be initiated ahead of time. Integration of MDCT scanners in the primary trauma survey provides a high standard of imaging in a very short time without endangering the patient. When dealing with multiple casualties, MDCT could be used also as an accurate and time-efficient means of hospital triage to diagnose and prioritize patients and to plan further surgical interventions and intensive care.

Critical Care↗
PubMed2003

Evaluation of minimally invasive percutaneous CT-controlled ventriculostomy in patients with severe head trauma.

Evaluation of percutaneous CT-controlled ventriculostomy (PCV) in patients with severe traumatic brain injury to measure intracranial pressure as a component of early clinical care. A consecutive series of 52 interventions with PCV was prospectively analyzed with regard to technical success, procedural time, time from the initial cranial computed tomography (CCT) until procedure and transfer to the intensive care unit (ICU). Additionally, the data was compared with a retrospective control group of 12 patients with 13 procedures of conventional burr-hole ventriculostomy (OP-ICP). The PCV was successful in all cases (52 of 52; 95% CI 94-100%). In 1 case a minor hemorrhage into the ipsilateral lateral ventricle was observed on CT scans due to an initially unsuccessful puncture (95% CI 0-6%). No infections occurred (95% CI 0-6%). In the control group with OP-ICP one catheter infection and one unsuccessful catheter placement occurred (each 8%, 95% CI 0-20%). The PCV led to a significant decrease of procedure time from 45 +/- 11 min (OP-ICP) to 20 +/- 12 min (PCV). The interval from the initial CCT until procedure (PCV 28 +/- 11 min, OP-ICP 78 +/- 33 min) and transfer to the ICU (PCV 69 +/- 34 min, OP-ICP 138 +/- 34 min) could also be significantly reduced (each with p<0.05, Mann-Whitney U-test). Percutaneous CT-controlled ventriculostomy is a safe and efficient method for ICP catheter placement during initial trauma room management. It significantly reduces the time of initial trauma room treatment.

Adult↗
PubMed2003

[Functional CT imaging: Load-dependent visualization of the subchondral mineralization by means of CT osteoabsorptiometry (CT-OAM)].

PURPOSE: Functional computed tomography for visualization and quantification of subchondral bone mineralization using CT osteoabsorptiometry (CT-OAM). MATERIALS AND METHODS: Tarsometatarsal (TMT) and metatarsophalangeal (MTP) joints of 46 human hallux valgus (HV) specimens were examined (sagittal 1/1/1 mm) on a single slice CT scanner SCT (Somatom Plus 4, Siemens AG). Subchondral bone pixels were segmented and assigned to 10 density value groups (Delta 100 HU, range 200 - 1200 HU) the pixels using volume rendering technique (VRT). The data analysis considered the severity of HV as determined by the radiographically measured HV-angle (a. p. projection). RESULTS: CT-OAM could generate reproducible densitograms of the distribution pattern of the subchondral bone density for all four joint surfaces (TMT and MTP joints). The bone density localization enables the assignment to different groups, showing a characteristic HV-angle-dependent distribution of the maximum bone mineralization of the load-dependent densitogram (p < 0.001). CONCLUSION: CT-OAM is a functional CT technique for visualizing and quantifying the distribution of the subchondral bone density, enabling a noninvasive load-dependent assessment of the joint surfaces. Load-dependent densitograms of hallux valgus specimens show a characteristic correlation with an increase of the HV-angle.

Absorptiometry, Photon↗
PubMed2003

[CT-guided aortic balloon occlusion in traumatic abdominal and pelvic bleeding].

PURPOSE: To introduce a new interventional method for CT-guided aortic balloon occlusion in patients with life-threatening abdominal or pelvic bleeding. MATERIALS AND METHODS: Three male patients (age 18, 30, and 45 years) with multiple trauma underwent CT-guided balloon occlusion of the aorta after CT identified an active abdominal or pelvic bleeding site and the patients became unstable (systolic blood pressure, BP < 80 mm Hg) despite resuscitation continuous volume. Using a right femoral approach, a 9F sheath was immediately introduced and the positions of the guide wire and balloon catheter (20 x 40 mm) were intermittently checked with CT scans and CT fluoroscopy. In one case, a C-clamp was applied to the pelvic ring under CT guidance for emergency stabilization of an unstable pelvic fracture. RESULTS: CT-guided aortic balloon occlusion and the mounting of the pelvic C-clamp were technically successful. Intervention time was 4 to 6 minutes for aortic balloon occlusion. All patients became at least temporarily stable hemodynamically with the blood pressure rising above 100 mmHg. The infrarenal occlusion catheters were left in place up to 60 minutes. Suprarenal occlusion was not performed. Two patients died due to protracted shock and complex injuries (injury severity score (ISS: 50 - 64). CONCLUSION: CT-guided aortic occlusion provides fast and effective bleeding control immediately after completion of the diagnostic CT. The procedure can be combined with other specific emergency surgical or interventional procedures. Experience with more patients is necessary for further evaluation of this new technique.

Adolescent↗
PubMed2002

Rapid identification of high-risk patients after minor head trauma (MHT) by assessment of S-100B: ascertainment of a cut-off level.

BACKGROUND: Elevated blood S-100B levels were described by several authors for reliable identification of patients with intracerebral complications after minor head trauma (MHT). Yet, test systems used so far require more than 3 hours processing period which is too long to enable immediate further diagnostic or therapeutic consequences. Therefore we validate a new rapid test version for S-100B measurements and established an effective cut-off level to identify high risk patients. METHODS: 104 patients suffering from MHT were enrolled. After taking blood samples S-100B values were achieved by the long-term and rapid (40 min processing time) test system, respectively, and compared using linear regression analysis. For determination of an effective cut-off level receiver operating characteristics curves were calculated in accordance with cranial computed tomography findings. RESULTS: S-100B concentrations correlated significantly using both test systems. A cut-off level of 0.18ng/ml was calculated in plasma samples. CONCLUSIONS: S-100B concentrations above the cut-off level measured within 40 min after blood sampling allows safe identification and immediate treatment of intracerebral lesions (e.g. epidural and subdural hematoma, subarachnoid hemorrhage, diffuse brain edema etc.) in MHT patients.

Blood Chemical Analysis↗
PubMed2002

[Interdisciplinary shock room management: personnel, equipment and spatial logistics in 3 trauma centers in Europe].

OBJECTIVE: To analyse common and divergent features of staff-related, equipmental and spatial/logistical concepts of three large trauma centers of highest health care level. METHODS: The health care mandate as well as the staff management, the organisational and the constructional-spacial structure of trauma room diagnostics and therapy of the trauma centers of the Universities of Leiden and Munich (Innenstadt) and the Zentralklinikum Augsberg are described. In particular the technical equipment and the process of the radiological diagnostic procedures in the trauma room are outlined. RESULTS: Staff availability and basic technical equipment of the trauma rooms are comparable between the three hospitals. Divergent concepts exist concerning the complexity of the initial radiologic examination protocols. Spacial connection and importance of computed tomography are also discussed controversially. Urgent interventional procedures are increasingly performed within the trauma room. Magnetic-resonance-tomography does not play a role in early care from multiple injured patients. CONCLUSION: Trauma centers have to meet certain personnel and technical prerequisites to guarantee a temporally optimised care for multiple injured patients. Differences between the three centers concerning the logistic sequence and the radiologic examination techniques used are mainly due to variable emphasis put on CT in the initial phase of patient care.

Critical Care↗
PubMed2002

[Structured radiologic diagnosis in polytrauma].

PURPOSE: Development of a concept for structured diagnostic imaging in patients with multiple trauma. MATERIAL AND METHODS: Evaluation of data from a prospective trial with over 2400 documented patients with multiple trauma. All diagnostic and therapeutic steps, primary and secondary death and the 90 days lethality were documented. Structured diagnostic imaging of multiple injured patients requires the integration of an experienced radiologist in an interdisciplinary trauma team consisting of anesthesia, radiology and trauma surgery. Radiology itself deserves standardized concepts for equipment, personnel and logistics to perform diagnostic imaging for a 24-h-coverage with constant quality. RESULTS: This paper describes criteria for initiation of a shock room or emergency room treatment, strategies for documentation and interdisciplinary algorithms for the early clinical care coordinating diagnostic imaging and therapeutic procedures following standardized guidelines. Diagnostic imaging consists of basic diagnosis, radiological ABC-rule, radiological follow-up and structured organ diagnosis using CT. Radiological trauma scoring allows improved quality control of diagnosis and therapy of multiple injured patients. CONCLUSION: Structured diagnostic imaging of multiple injured patients leads to a standardization of diagnosis and therapy and ensures constant process quality.

Emergency Service, Hospital↗
PubMed2002

[Radiological diagnosis in acute craniocerebral trauma].

PURPOSE: Head injury alone or in combination with multiple trauma is the main cause of death and severe disability in individuals under 45 years old. This review is intended to describe the relevant imaging modalities, to analyze their specific value and limitations and to illustrate the most important radiologic findings. The indications for diagnostic imaging within the context of an interdisciplinary linkage of diagnostic and therapeutic measures are discussed. MATERIAL AND METHODS: Recent publications are analyzed and compared to the experiences of our own hospital. In terms of a critical synoptic assessment the currently best standard of care is described in consideration of an interdisciplinary care concept. RESULTS: Radiologic imaging modalities crucially contribute to the complete injury assessment and provide an indispensable basis for any therapeutic decision. Comprehensive neuromonitoring and reliable demonstration of delayed or secondary brain damage is impossible without modern imaging technology. Computed tomography (CT) further continues to be the most important imaging modality, while magnetic resonance imaging despite it's partly superior diagnostic informations remains reserved to particular diagnostic problems. CONCLUSIONS: Suitable constructive prerequisities, an interdisciplinary care concept and integration of the radiologist in hospital-adapted diagnostic and therapeutic algorithms significantly improves the outcome of patients with acute head injury. Beside the correct diagnosis itself the time to establish a diagnosis above all has a crucial impact on successful management and good outcome of these patients.

Angiography, Digital Subtraction↗
PubMed2002

[Standardized evaluation of trauma patients: requirements for diagnostic imaging].

INTRODUCTION: Evaluation of trauma systems requires a complete and exact injury classification. The purpose of this study was the introduction of the Abbreviated injury scale (AIS) for radiological trauma scoring. The development of these easy to use coding tools is essential for prompt quality management of trauma. MATERIAL AND METHODS: Standardized radiological injury description using a modified Abbreviated injury scale in combination with a Microsoft Excel spreadsheet allows an immediate calculation of the probability of survival according to TRISS methodology. RESULTS: Computed tomography is the main instrument for injury scoring in trauma care. Postmortem scanning provides a direct feedback for trauma teams especially in case when autopsy is not possible. CONCLUSION: Computed tomography enables in combination with a standardized injury description exact trauma scoring. Quality management of trauma care depends on a valid and reliable calculation of the probability of survival using TRISS.

Abbreviated Injury Scale↗
PubMed2002

[Detection of tibial condylar fractures using 3D imaging with a mobile image amplifier (Siemens ISO-C-3D): Comparison with plain films and spiral CT].

PURPOSE: To analyze a prototype mobile C-arm 3D image amplifier in the detection and classification of experimental tibial condylar fractures with multiplanar reconstructions (MPR). METHOD: Human knee specimens (n = 22) with tibial condylar fractures were examined with a prototype C-arm (ISO-C-3D, Siemens AG), plain films (CR) and spiral CT (CT). The motorized C-arm provides fluoroscopic images during a 190 degrees orbital rotation computing a 119 mm data cube. From these 3D data sets MP reconstructions were obtained. All images were evaluated by four independent readers for the detection and assessment of fracture lines. All fractures were classified according to the Müller AO classification. To confirm the results, the specimens were finally surgically dissected. RESULTS: 97 % of the tibial condylar fractures were easily seen and correctly classified according to the Müller AO classification on MP reconstruction of the ISO-C-3D. There is no significant difference between ISO-C and CT in detection and correct classification of fractures, but ISO-CD-3D is significant by better than CR. CONCLUSION: The evaluation of fractures with the ISO-C is better than with plain films alone and comparable to CT scans. The three-dimensional reconstruction of the ISO-C can provide important information which cannot be obtained from plain films. The ISO-C-3D may be useful in planning operative reconstructions and evaluating surgical results in orthopaedic surgery of the limbs.

Humans↗
PubMed2002

[Sedation analgesia in interventional radiology].

PURPOSE: Development of a save and effective protocol for analgosedation of patients undergoing painful interventional procedures. MATERIAL AND METHODS: In a prospective trial a consecutive series of 72 adult patients underwent analgosedation during painful interventions. A radiologist performed the analgosedation, the patients received a combination of a shortly effective piperidine derivative (Alfentanil [Rapifen(R)]; 7.5 - 15 microgram/kg body weight) and Benzodiazepine (midazolam [Dormicum(R)]; 20 microgram/kg body weight). After pre-procedure oxygenation patients were continuously monitored. Pain and discomfort were scored using an established visual-analog pain score (0 - 10). A control group (n = 24) had received midazolam, pentazocine or fentanyl according to the study protocol. RESULTS: All procedures could be carried out by an interventional radiologist and a nurse and/or technologist only. In 69/72 cases adequate analgosedation could be achieved. Injection of alfentanil was titrated, with a rapid onset and short acting effect of the analgesia. Patients reported an average pain score of 2.6 vs. 4.5 in the control group. Over 55 % experienced no or mild pain (score 0 - 3), in the control group only 8 % reached this level. CONCLUSION: A combination of shortly effective alfentanil and midazolam allows interventional radiologists to perform major procedures alone under effective analgosedation. This medication scheme is superior to the medication upon demand.

Adjuvants, Anesthesia↗
PubMed2002

[Studies on image quality, high contrast resolution and dose for the axial skeleton and limbs with a new, dedicated CT system (ISO-C-3 D)].

PURPOSE: Evaluation of 3D-CT imaging of the axial skeleton and different joints of the lower and upper extremities with a new dedicated CT system (ISO-C-3D) based on a mobile isocentric C-arm image amplifier. MATERIAL AND METHODS: 27 cadaveric specimes of different joints of the lower and upper extremities and of the spinal column were examined with 3D-CT imaging (ISO-C-3D). All images were evaluated by 3 radiologists for image quality using a semiquantitative score (score value 1: poor quality; score value 4: excellent quality). In addition, dose measurements and measurements of high contrast resolution were performed in comparison to conventional and low-dose spiral CT using a high contrast phantom (Catphan, Phantom Laboratories). RESULTS: Adequate image quality (mean score values 3 - 4) could be achieved with an applied dose comparable to low-dose CT in smaller joints such as wrist, elbow, ankle and knee. A remarkably inferior image quality resulted in imaging of the hip, lumbar and thoracic spine (mean score values 2 - 3) in spite of almost doubling the dose (dose increased by 85 percent). The image quality of shoulder examinations was insufficient (mean score value 1). Phantom studies showed a high-contrast resolution comparable to helical CT in the xy-axis (9 lp/cm). CONCLUSION: Preliminary results show, that image quality of C-arm-based CT-imaging (ISO-C-3D) seems to be adequate in smaller joints. ISO-C-3D images of the hip and axial skeleton show a decreased image quality, which does not seem to be sufficient for diagnosing subtle fractures.

Arm↗