Biomedical subjects

M Treitl

Publications and source records attributed to M Treitl.

16 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↗

PubMed2007

[Imaging in the early diagnosis of changes in the hand of patients suffering from rheumatoid arthritis. Is ultrasound a true alternative for low-field magnetic resonance scanning, 3-phase bone scintigraphy and conventional x-rays?].

PURPOSE: Besides the use of conventional x-rays in the diagnostic work-up of initial changes in patients suffering from rheumatoid arthritis (RA), 3-phase bone scintigraphy (3P-Sz) is as well established as magnetic resonance imaging (MRI). The aim of this study was to compare the diagnostic value of ultrasound of the hands with proven methods such as conventional x-rays, low-field MRI and 3P-Sz. METHODS: A total of 30 patients were studied using a 1 day protocol with ultrasound, 3P-Sz, MRI and x-ray of the hands. Images were visually assessed by two blinded nuclear medicine physicians and radiologists and classified as RA typical and non-RA typical changes. All methods were compared to the summarized findings interpreted by a rheumatologist after 2 years. RESULTS: Of the 30 patients, 19 presented with clinical symptoms of initial changes due to rheumatoid arthritis. Ultrasound revealed 14/19 patients with the correct diagnosis. Conventional x-rays indicated 11/19 patients, while 3P-Sz (100%) and low-field MRI (95%) showed high sensitivity. It was possible to differentiate between inflammation and inconspicuous findings. CONCLUSIONS: An experienced examiner can use ultrasound effectively for the initial diagnosis of RA. Based on its low cost, ultrasound is a valid alternative to conventional x-rays.

Adult↗

PubMed2006

[Soft tissue manifestations of early rheumatic disease: imaging with MRI].

PURPOSE: The aim of this study was to evaluate typical magnetic resonance imaging (MRI) findings in early rheumatic diseases manifesting at the soft tissues of the hand using a retrospective analysis. MATERIAL AND METHODS: A total of 186 MRI examinations of patients with clinical suspicion of a rheumatic disease were evaluated in a consensus reading by two experienced radiologists. All imaging patterns were assessed with respect to their type and localization. Under blinded and non-blinded conditions diagnoses were correlated with final clinical diagnosis. RESULTS: The most frequent diagnoses were rheumatoid arthritis (RA, 45.7%) and psoriatic arthritis (PsA, 15.6%). The mean correlation between clinical and MRI diagnosis (r) was 0.75 in blinded and 0.853 in non-blinded reading (p <0.001). The following extra-articular imaging patterns were found: synovitis (59.1%), tendovaginitis (91.4%), dactylitis (14.5%), and bone marrow edema (18.3%). Only dactylitis was specific for a particular rheumatic disease (PsA; r=0.934; sensitivity 84.9%, specificity 82.4%). CONCLUSION: Inflammatory conditions of the hand can be reliably detected with MRI. In many cases the definite diagnosis can only be made when taking clinical, serological, and radiographic results into account (+13.7% increase of significance).

Adult↗

PubMed2006

[Chronic critical ischemia of the lower leg: pretherapeutic imaging and methods for revascularization].

Each year 1-2% of patients with peripheral arterial occlusive disease (pAOD) develop critical limb ischemia (CLI), characterized by rest pain and peripheral ulcer or gangrene. This aggravation of the disease is accompanied by an increase of the 1-year mortality rate up to 25% and a similarly increased frequency of major amputation. We can choose between conservative, endovascular, and surgical procedures for an adequate therapy of the underlying vascular stenoses or occlusions. Yet, clear therapeutic recommendations only exist for suprapopliteal lesions. However, in a number of cases, especially in diabetics, target lesions have an infrapopliteal location. Since endovascular procedures have undergone significant improvement in the last few years, the following review discusses methods for infrapopliteal revascularization taking into consideration the newest publications on this topic.

Angioplasty↗

PubMed2006

[Stenting of the SFA--indications, techniques, results].

Aggressive risk factor modification, change of eating habits, exercise programs, and forceful antiplatelet therapy are the most important tools for the treatment of PAOD in symptomatic patients suffering from intermittent claudication. There are however no guidelines for revascularization at this stage. Endovascular treatment has been increasingly utilized over the last decade and increasingly displaced vascular surgery. Amongst numerous endovascular techniques beside PTA, stents meanwhile play the most important role due to constant technical progress. Results regarding the rate of restenosis or patency rates still remain worse compared to other vascular beds. This paper gives a review over recent results, currently available stent techniques, and possible indications for the endovascular therapy of an artery, which has turned out to be the biggest ordeal for material and construction of stents.

Blood Vessel Prosthesis↗

PubMed2006

[Comparison of different review displays with respect to the detection of low-contrast details in digital radiographs].

PURPOSE: Assessment of low-contrast details in digital radiographs on different review displays (RD). MATERIALS AND METHODS: 20" flat screen panels (RD1: standard color LCD-TFT, RD2: monochrome LCD-TFT for radiological reading, RD1*: RD1 with optional image inversion; 205 cd/m (2) luminance, respectively) were evaluated. At 30 lx ambient lighting, 10 radiologists gradually increased the contrast (constant steps) for both a homogeneous picture and a cutout of a thorax radiography of n = 480 simulated nodules until they became recognizable. RESULTS: In the case of bright nodules on an anthropomorphic background, the use of image inversion produced significantly better results. No other significant differences were detected. CONCLUSION: Provided that the working environment is not bright, the results suggest that low-cost RD can be used for the recognition of low-contrast details in radiographies of the chest. Further studies including more display models are necessary. Among different ambient lighting and luminance settings, these studies should include a closer analysis of the special features of digital systems such as brightness/contrast adaptation, picture enlargement (zoom shot), and image inversion.

Equipment Design↗

PubMed2005

[DRG and OPS-301: effects on the acquisition performance in radiology].

Reimbursement for inpatient services rendered based on comparable daily care rates, case-based flat rates, and special fees as practiced until now has been replaced by the system of diagnosis-related groups. Up until 2004, operation and procedure system (OPS 301) codes could be processed completely automatically by appropriate adaptation of the radiology information system (RIS). Because of further differentiation of OPS codes in the 2005 version, it is no longer possible to unambiguously determine OPS codes automatically. Our goal was to fulfill these additional requirements with as little extra effort as possible. In 36 of 2138 procedures during an observation period of 12 days, i.e., 4/day, manual input on the part of the radiology technical assistant and quality assurance by the diagnosing physician were necessary. This is only needed in complicated procedures for which the minor added effort is negligible in comparison to the entire effort expended for the procedure. We were thus able to achieve the goal of near automation of ascertaining OPS codes.

Databases, Factual↗

PubMed2005

[PACS: storage and retrieval of digital radiological image data].

BACKGROUND: Efficient handling of both picture archiving and retrieval is a crucial factor when new PACS installations as well as technical upgrades are planned. MATERIALS AND METHODS: For a large PACS installation for 200 actual studies, the number, modality,and body region of available priors were evaluated. In addition, image access time of 100 CT studies from hard disk (RAID), magneto-optic disk (MOD), and tape archives (TAPE) were accessed. RESULTS: For current examinations priors existed in 61.1% with an averaged quantity of 7.7 studies. Thereof 56.3% were within 0-3 months, 84.9% within 12 months, 91.7% within 24 months, and 96.2% within 36 months. On average, access to images from the hard disk cache was more than 100 times faster then from MOD or TAPE. CONCLUSION: Since only PACS RAID provides online image access, at least current imaging of the past 12 months should be available from cache. An accurate prefetching mechanism facilitates effective use of the expensive online cache area. For that, however, close interaction of PACS, RIS, and KIS is an indispensable prerequisite.

Database Management Systems↗

PubMed2005

[Possibilities for workflow optimization in radiology departments beyond RIS and PACS].

Technological progress and the rising cost pressure on the healthcare system have led to a drastic change in the work environment of radiologists today. The pervasive demand for workflow optimization and increased efficiency of its activities raises the question of whether by employment of electronic systems, such as RIS and PACS, the potentials of digital technology are sufficiently used to fulfil this demand. This report describes the tasks and structures in radiology departments, which so far are only insufficiently supported by commercially available electronic systems but are nevertheless substantial. We developed and employed a web-based, integrated workplace system, which simplifies many daily tasks of departmental organization and administration apart from well-established tasks of documentation. Furthermore, we analyzed the effects exerted on departmental workflow by employment of this system for 3 years.

Database Management Systems↗

PubMed2005

[Digital teaching archive. Concept, implementation, and experiences in a university setting].

Film-based teaching files require a substantial investment in human, logistic, and financial resources. The combination of computer and network technology facilitates the workflow integration of distributing radiologic teaching cases within an institution (intranet) or via the World Wide Web (Internet). A digital teaching file (DTF) should include the following basic functions: image import from different sources and of different formats, editing of imported images, uniform case classification, quality control (peer review), a controlled access of different user groups (in-house and external), and an efficient retrieval strategy. The portable network graphics image format (PNG) is especially suitable for DTFs because of several features: pixel support, 2D-interlacing, gamma correction, and lossless compression. The American College of Radiology (ACR) "Index for Radiological Diagnoses" is hierarchically organized and thus an ideal classification system for a DTF. Computer-based training (CBT) in radiology is described in numerous publications, from supplementing traditional learning methods to certified education via the Internet. Attractiveness of a CBT application can be increased by integration of graphical and interactive elements but makes workflow integration of daily case input more difficult. Our DTF was built with established Internet instruments and integrated into a heterogeneous PACS/RIS environment. It facilitates a quick transfer (DICOM_Send) of selected images at the time of interpretation to the DTF and access to the DTF application at any time anywhere within the university hospital intranet employing a standard web browser. A DTF is a small but important building block in an institutional strategy of knowledge management.

Computer-Assisted Instruction↗

PubMed2005

[Recommendations for the selection of storage media for archiving digital radiological image data based on the comparison of retrieval times at different PACS archive levels].

PURPOSE: Recommendations for archiving digital radiological image data based on the comparison of retrieval times for different PACS archive levels. MATERIALS AND METHODS: For a large PACS installation (Agfa Impax, Release 4.1), image retrieval times for radiological standard examinations (chest radiographs with 2, MRI with 250, CT with 100 and 1000 images; n = 120, each) from hard disk array, magneto-optical disk (MOD), and magnetic tape archives (TAPE) were examined in high and low network traffic load. RESULTS: Even large CT examinations (1000 images) were available from hard disk arrays within 4.0 +/- 0.8 s, smaller studies within 1.8 +/- 0.3 s. Radiographic image retrieval from MOD (30 +/- 4.7 s) was more then 50 % faster than from TAPE. For typical cross-sectional studies, the velocity gain amounted to 19 %. For both technologies, no significant difference was found for large CT examinations (651 +/- 144 s). For high and low network traffic load scenarios, image retrieval times from hard disk, MOD, and TAPE archives increased by 87 %, 7 %, and 22 %, respectively. CONCLUSION: Hard disk arrays are specifically suited as departmental intermediate storage media because they allow fast access to current and previous examinations within a short time. Performance properties enable both MOD and TAPE systems to serve as long-term archives. However, MOD archives are less flexible in the expansion of storage capacity and at present the medium costs per memory unit are about 2 - 3 times higher than for tape archives. The use of existing MOD-archives may be adequate as intermediate archives. For new PACS installations or system expansions, however, it is recommended to combine a sufficiently large local data memory (RAID) with data storage on tape archives outside the radiological unit that can be used by other departments as well. Future development of hard disk prices will show whether archiving for the whole data retention period may be handled by RAID systems. In any case, prefetching problems and waiting periods for demanded pre-studies would not occur any more.

Humans↗

PubMed2005

Initial clinical results with a new needle screen storage phosphor system in chest radiograms.

PURPOSE: To evaluate image quality and anatomical detail depiction in dose-reduced digital plain chest radiograms using a new needle screen storage phosphor (NIP) in comparison to full dose conventional powder screen storage phosphor (PIP) images. MATERIALS AND METHODS: 24 supine chest radiograms were obtained with PIP at standard dose and compared to follow-up studies of the same patients obtained with NIP with dose reduced to 50 % of the PIP dose (all imaging systems: AGFA-Gevaert, Mortsel, Belgium). In both systems identical versions of post-processing software supplied by the manufacturer were used with matched parameters. Six independent readers blinded to both modality and dose evaluated the images for depiction and differentiation of defined anatomical regions (peripheral lung parenchyma, central lung parenchyma, hilum, heart, diaphragm, upper mediastinum, and bone). All NIP images were compared to the corresponding PIP images using a five-point scale (- 2, clearly inferior to + 2, clearly superior). Overall image quality was rated for each PIP and NIP image separately (1, not usable to 5, excellent). RESULTS: PIP and dose reduced NIP images were rated equivalent. Mean image noise impression was only slightly higher on NIP images. Mean image quality for NIP showed no significant differences (p > 0.05, Mann-Whitney U test). CONCLUSION: With the use of the new needle structured storage phosphors in chest radiography, dose reduction of up to 50 % is possible without detracting from image quality or detail depiction. Especially in patients with multiple follow-up studies the overall dose can be decreased significantly.

Adult↗

PubMed2004

IT services in a completely digitized radiological department: value and benefit of an in-house departmental IT group.

To analyze the benefit of a departmental IT group in comparison to support by hospital IT groups or system manufacturers in a completely digitized radiological department. The departmental IT group comprises a fulltime IT specialist, two student assistants and four clinical employees participating 1 day/week. For 18 months IT problems were quantified and specified according to urgency, responsibility and affected system by use of an intranet-based reporting system. For each IT service provider the performance and duration of problem solution was evaluated. In 18 months 3,234 IT problems emerged. 88.7% were solved by the departmental IT group. In 474 cases (14.7%) a solution within 2 h was required. The departmental IT group solved 35.8% within 30 min, system manufacturers needed 18 h 38 min in mean. The departmental IT group solved 90.2% of the problems within a time limit. System manufacturers met the limit in 60.1% with a mean duration of 7 days 21 h. In 6.7% of the cases, support by system manufacturers was indispensable. A considerable proportion of IT problems in completely digitized radiological departments can be solved by a departmental IT group, providing a fast and cost-efficient first-level IT support with effective prevention of major breaks in the workflow. In a small number of cases support by system manufacturers remains necessary.

Computer Communication Networks↗

PubMed2004

[Diagnosis of initial changes in patients suffering from rheumatoid arthritis. Two years follow up control with a low-field magnetic resonance scanner, 3-phase bone scintigraphy and conventional x-ray].

UNLABELLED: Besides conventional x-ray, in the diagnostic work up of initial changes in patients suffering from rheumatoid arthritis (RA), 3-phase bone scintigraphy (3P-Sz) is as well established as magnetic resonance imaging (MRI). The AIM of this study was to compare the diagnostic value of a newly developed low field MRI with proven methods such as conventional x-ray and 3P-Sz. PATIENTS, METHODS: 42 patients were studied using a one days protocol with 3P-Sz, MRI, and x-ray of the hands with yearly follow up examinations. Images were visually assessed by two blinded nuclear medicine physicians and radiologists and classified as RA-typical and non-RA-typical changes. All methods were compared to the summarised findings interpreted by a rheumatologist in consideration of the Ritchie articular index as gold-standard. RESULTS: 24/42 patients presented with clinical symptoms of initial changes by rheumatoid arthritis. Conventional x-ray revealed in 20/24 patients within the correct diagnosis in the study period. On the other hand 3P-Sz and low field MRI concordantly showed all 24 patients with initial changes due to RA. Time of detection showed variations with a tendency to later findings by conventional x-ray. CONCLUSIONS: In the diagnostic work up of initial changes conventional x-ray should be the first choice in imaging. Our findings suggest that MRI represents an equally sensitive method for the diagnosis of initial changes due to RA in the region of the hands as compared to the 3P-Sz. The limitation of the low field MRI is the small field of view, so we prefer 3P-Sz or high field MRI in the diagnosis of patients with suspected RA.

Arthritis, Rheumatoid↗

PubMed2003

[Systematic characterization of sonomorphological changes in the early stage of rheumatoid arthritis].

AIM: The early stage of rheumatoid arthritis (RA) is primarily manifested in the soft tissue of the hand. Although ultrasound (US) is regarded as an important imaging process in diagnostic medicine, precise characterization of sonomorphological changes has not yet been undertaken. METHOD: 20 patients with RA were examined with US. Two radiologists described semiquantitatively the characteristics of synovial changes in the hand in a consensus-based process and measured the synovial width. Statistical methods were used to determine whether the various synovial changes differed significantly and to identify the most frequent locations of changes. RESULTS: On the basis of the significant differences in morphology and synovial width, it is possible to distinguish between unremarkable findings, pannus tissue and band-like synovitis. Pannus tissue is most frequently found on the finger flexor tendons (FFT), the metacarpophalangeal joints (MCP) and the tendon of M. extensor carpi ulnaris (ECU). Band-like synovitis exhibits an uncharacteristic distribution pattern with a slight propensity to favour these locations. CONCLUSION: The FFT, MCP joints and ECU tendons are particularly important in systematic US screening of the hand for the purpose of establishing reliable evidence of inflammatory changes. Different stages of RA can be identified on the basis of the characteristic types of synovitis and the number of joints and tendons affected.

Adult↗

PubMed2002

[Diagnosis of initial changes in the hand of patients with rheumatoid arthritis--comparison between low-field magnetic resonance imaging, 3-phase bone scintigraphy and conventional x-ray].

UNLABELLED: Besides conventional X-rays, in the diagnostic work up of initial changes in patients suffering from rheumatoid arthritis (RA), 3-phase bone scintigraphy (3P-Sz) is as well established as magnetic resonance imaging (MRI). The aim of this study was to compare the diagnostic value of the newly developed low field MRI with the proven methods X-rays and 3P-Sz. METHODS: 65 patients (47f, 18m; 20-86 yrs) were studied on a one day protocol with 3P-Sz (550 MBq Tc-99m DPD), MRI and X-rays of the hands. Images were visually analysed by two blinded nuclear medicine physicians and radiologists and classified as a) RA-typical, b) inflammatory, non-RA-typical and c) non inflammatory changes. All methods were compared to 3P-Sz as golden standard. RESULTS: In comparison to 3P-Sz, low field MRI presents with almost equal sensitivity and specificity in rheumatoid-typical and inflammatory changes. Conventional X-rays revealed in arthritis-typical changes as well as in inflammatory changes a significantly lower sensitivity and also a lower negative predictive value while specificity equals the one of MRI. Quantitative analysis of 3P-Sz using ROI-technique unveiled significantly higher values in patients with rheumatoid arthritis than in those with no inflammatory changes. CONCLUSION: MRI represents an equally sensitive method in the initial diagnosis of rheumatoid-typical and inflammatory changes in the region of the hands as compared to the 3P-Sz. Besides the basic diagnosis with conventional X-rays, 3P-Sz is still the recommended method of choice to evaluate the whole body when RA is suspected. Additionally, quantitative analysis of the 3P-Sz using the ROI technique in the region of the hands reveals statistically significant results and should therefore be taken into account in the assessment of inflammatory changes.

Adult↗