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Biomedical subjects

A Schröter

Publications and source records attributed to A Schröter.

At least 19 recordsLinked to original sources
PubMed2006

Teleradiology applications with DICOM-e-mail.

For the connection of several partners to a Dicom-e-mail based teleradiology network concepts were developed to allow the integration of different teleradiology applications. The organisational and technical needs for such an integration were analysed. More than 60 institutions including 23 hospitals in the Rhein-Neckar-Region, Germany were connected. The needed functionality was grouped in six teleradiology applications (emergency consultation, tele-guided examinations, expert consultations, cooperative work, scientific cooperations and homework with on call services) and their technical and organisational needs according to availability, speed of transfer, workflow definitions and data security needs was analysed. For the local integration of teleradiology services the setup and workflow is presented for a standalone teleradiology workstation and a server based teleradiology gateway. The line type needed for different groups of applications and users is defined. The security concept and fallback strategies are laid out, potential security problems and sources of errors are discussed. The specialties for the emergency teleradiology application are presented. The DICOM-e-mail protocol is a flexible and powerful protocol that can be used for a variety of teleradiology applications. It can meet the conditions for emergency applications but is limited if synchronous applications like teleconferences are needed.

Computer Security↗
PubMed2005

Standardization of teleradiology using Dicom e-mail: recommendations of the German Radiology Society.

Until recently there has been no standard for an interoperable and manufacturer-independent protocol for secure teleradiology connections. This was one of the main reasons for the limited use of teleradiology in Germany. Various teleradiology solutions have been developed in the past, but the vast majority have not been interoperable. Therefore an ad hoc teleradiology connection was impossible even between partners who were already equipped with teleradiology workstations. Based on the evaluation of vendor-independent protocols in recent years the IT Working Group (AGIT) of the German Radiology Society set up an initiative to standardize basic teleradiology. An e-mail based solution using the Dicom standard for e-mail attachments with additional encryption according to the OpenPGP standard was found to be the common denominator. This protocol is easy to implement and safe for personalized patient data and fulfills the legal requirements for teleradiology in Germany and other countries. The first version of the recommendation was presented at the 85th German Radiology Convention in 2004. Eight commercial and three open-source implementations of the protocol are currently available; the protocol is in daily use in over 50 hospitals and institutions.

Computer Communication Networks↗
PubMed2005

[Teleradiology with DICOM e-mail: recommendations of @GIT].

E-mail is ideal for ad-hoc connections in teleradiology. The DICOM standard offers the possibility to append DICOM data types as a MIME attachment to any e-mail, thus ensuring the transmission of the original DICOM data. Nevertheless, there are additional requirements (e.g. protection of data privacy) which must be obeyed. Because of the lack of given standards which would grant interoperability as well as manufacturer independence, teleradiology has not been established in Germany until today. Therefore, the IT-Team (Arbeitsgemeinschaft fur Informationstechnologie, @GIT) of the Radiological Society of Germany (Deutsche Rontgengesellschaft, DRG) set up an initiative to standardise telemedicine by using e-mail. Its members agreed that an e-mail-based variant would be the most practicable way to a communication solution -- as easy to implement as to use. In their opinion, e-mail represents the smallest common denominator for a safe data interchange that would fulfill the legal advantages for telemedicine in Germany.

Computer Communication Networks↗
PubMed2005

Whipple's disease presenting as an isolated lesion of the cervical spinal cord.

Chronic myelitis from Whipple's disease of the spinal cord is extremely rare. The differential diagnosis includes chronic inflammatory lesions, viral or bacterial infections, and tumours of the spinal cord. Here we present a 50-year-old man with mild sensory deficits because of a large lesion of the cervical spinal cord who markedly showed improvement during probatory antibiotic therapy. PCR and jejunal biopsy were initially negative and only later confirmed the diagnosis of Whipple's disease. Clinical and neuroradiological criteria are suggested which may be of help in the early diagnosis of spinal Whipple's disease before confirmation by molecular biology or histology.

Anti-Bacterial Agents↗
PubMed2004

Sporadic Creutzfeldt-Jakob disease: magnetic resonance imaging and clinical findings.

OBJECTIVE: To assess if clinical features, prion protein codon 129, and molecular subtype correlate with MRI basal ganglia hyperintensity in sporadic Creutzfeldt-Jakob disease (CJD). METHODS: The authors studied 219 patients including 153 confirmed CJD cases for their neurologic symptoms and MRI findings. The MRI was assessed by a blinded investigator for the presence of high signal intensity on T2-weighted images in the basal ganglia. RESULTS: Patients with basal ganglia high signal on T2-weighted images were more likely to present with rapid progressive dementia in an early stage and shorter disease duration (median 6.7 months and 8.6 months). Surprisingly, among the CJD cases, patients without signal increase of the basal ganglia were shown to have a higher frequency of extrapyramidal disturbances (82% vs 70%). More striking differences were found for symptoms such as depression and sensory disturbances, which were more frequent among cases without signal increase. MRI was more likely to be diagnostic in patients with MV2 molecular subtype. CONCLUSIONS: Selected clinical and pathologic features correlate with the presence of basal ganglia high signal on T2-weighted MRI in patients with definite or probable CJD.

Adult↗
PubMed2004

CSF lactate dehydrogenase activity in patients with Creutzfeldt-Jakob disease exceeds that in other dementias.

The diagnosis of Creutzfeldt-Jakob disease (CJD) is still made by exclusion of other dementias. We now evaluated lactate dehydrogenase (LDH) in the cerebrospinal fluid (CSF) as a possible additional diagnostic tool. CSF LDH levels of patients with CJD (n = 26) were compared with those in other dementias (n = 28). LDH isoenzymes were determined in a subset (n = 9). Total LDH and isoenzyme LDH-1 were significantly higher, whereas the fractions of LDH-2 and LDH-3 were significantly lower in CJD patients. We conclude that in addition to established CSF parameters, LDH and its isoenzymes might serve as a further help to discriminate between CJD and other dementias.

Aged↗
PubMed2004

The integration of medical images with the electronic patient record and their web-based distribution.

Medical images are currently created digitally and stored in the radiology department's picture archiving and communication system. Reports are usually stored in the electronic patient record of other information systems, such as the radiology information system (RIS) and the hospital information system (HIS). But high-quality services can only be provided if electronic patient record data is integrated with digital images in picture archiving and communication systems. Clinicians should be able to access both systems' data in an integrated and consistent way as part of their regular working environment, whether HIS or RIS. Also, this system should allow for teleconferencing with other users, eg, for consultation with a specialist in the radiology department. This article describes a web-based solution that integrates the digital images of picture archiving and communication systems with electronic patient record/HIS/RIS data and has built-in teleconferencing functionality. This integration has been successfully tested using three different commercial RIS and HIS products.

Humans↗
PubMed2004

Kinematical analysis of handwriting movements in depressed patients.

OBJECTIVE: Motor disturbances are a relevant aspect of depression. Kinematical analysis of movements can be applied to explore which type of motor dysfunction is associated with depression. We hypothesized that depressed patients draw and write significantly slower than controls and that motor disturbances become more pronounced under bi-manual demands. METHOD: We examined 37 depressed patients and 37 healthy controls using a digitizing graphic tablet and subsequent kinematical analysis of handwriting and rapid drawing movements. RESULTS: Depressed patients performed drawing with significantly less regular velocity than controls (P < 0.001), but normal velocity. Motor differences between patients and controls did not increase under bi-manual demands. Handwriting of patients was abnormally slow (P = 0.04). CONCLUSION: Irregular patterns of velocity peaks in depressed patients point to basal ganglia dysfunction and/or deficient activity of the sensorimotor cortex and the supplementary motor area as a possible substrate of hand-motor disturbances in depression.

Adult↗
PubMed2003

Frequency of manic symptoms during a depressive episode and unipolar 'depressive mixed state' as bipolar spectrum.

OBJECTIVE: To report the frequency of intra-episode manic symptoms in depressive episodes, and to evaluate unipolar depressive mixed state (DMS) as bipolar spectrum. METHOD: A total of 958 (863 unipolar, 25 bipolar II, and 70 bipolar I) depressive in-patients were assessed in terms of manic symptoms at admission, and several clinical variables using standardized methods. RESULTS: The frequency of manic symptoms (flight of idea, logorrhea, aggression, excessive social contact, increased drive, irritability, racing thoughts, and distractibility) was significantly higher in bipolar depressives than in unipolar depressives. Unipolar depressives with DMS - defined as having two or more manic symptoms - had more similarities to bipolar depressives than to other unipolar depressives in clinical variables such as onset age, family history of bipolar disorder, and possibly suicidality. CONCLUSION: Depressive mixed state is frequent, particular in bipolar depressives. Unipolar depressives with DMS may be better classified into bipolar spectrum.

Adult↗
PubMed2003

Long-term inter-episode stability of syndromes underlying mania.

OBJECTIVE: To explore the stability of diverse manic presentations across manic recurrences. METHOD: A total of 253 bipolar patients who experienced two or more hospitalizations, because of consecutive manic (or mixed) episodes, during a 20-year period were included. All patients had second hospitalizations with an mean interval of 773 days, while 126 and 91 patients had third and fourth hospitalizations with mean intervals of 1559 and 2237 days from the index hospitalization, respectively. Seven symptom scores, previously factor-validated, were calculated. RESULTS: Depressive mood, irritable aggression, psychomotor/thought inhibition, mania, emotional lability/agitation and psychosis were moderately correlated across the index and subsequent hospitalizations. CONCLUSION: A majority of diverse manic presentations were stable across manic recurrences. The stability was not restricted to two consecutive recurrences but appeared widespread over the long-term course of bipolar disorder. The finding may serve for the development of more effective long-term treatment strategies and a clinically more reasonable subtyping of mania.

Adolescent↗
PubMed2003

Kinematic analysis of handwriting movements in patients with Alzheimer's disease, mild cognitive impairment, depression and healthy subjects.

A variety of studies have demonstrated that motor disorders, parkinsonism and extrapyramidal motor symptoms (EPMS) are common in patients with Alzheimer's disease (AD). Several studies have reported an association of EPMS with severity, progression and poor prognosis of AD. The majority of these studies used clinical assessments for the rating of EPMS. In this study, kinematic handwriting analysis was used to quantify differences in fine hand motor function in patients with probable AD and mild cognitive impairment (MCI, as an assumed initial stage of AD) compared to depressed patients and healthy controls. Both patients with MCI and patients with probable AD exhibited loss of fine motor performance. Movements of AD patients were significantly less regular than those of healthy controls.

Aged↗
PubMed2002

[Evaluation of CHILI teleradiology network 4 years after clinical implementation].

The CHILI teleradiology network has more than 60 installations in Germany and the USA. Radiological images and cardiological multiframe series are exchanged in clinical routine. This article investigates in what way and how often the system is used. This is done by means of accounting files that are produced automatically by the system. User functions, transmission protocols, data quantity, frequencies and time of data transmission and teleconferences are evaluated and discussed in this paper. Different application scenarios have been identified and are described and analyzed as well. An important result is, that the system is not merely an emergency system. Instead, it is used in daily routine as a multifunctional, multimodality workstation with advanced features for teleradiology and telecardiology.

Computer Communication Networks↗
PubMed2001

Unaltered apoptotic behaviour of mononuclear cells from patients with sporadic Creutzfeldt-Jakob disease.

Creutzfeldt-Jakob disease (CJD) belongs to the group of transmissible spongiform encephalopathies. It is suspected that a pathologically altered form of the prion protein (PrPSc) is the decisive trigger of the disease. Data from animal experiments suggest an involvement of the lymphatic system in the intracorporal transport of PrPSc. However, it has not so far been possible to detect PrPSc on mononuclear cells (MNCs) either in the sporadic form of CJD or in the new variant of CJD (vCJD). In order to determine a possible alteration of MNCs in CJD, we investigated the natural and induced apoptotic behaviour of these cells. MNCs from 19 patients with sporadic CJD and from 20 patients with other neurological disorders were used. The cells were analysed by fluorescence cytometry with and without apoptosis induction by xanthine oxidase and hypoxanthine. The apoptosis rate was quantified using the stain 7-amino-actinomycin D (7-AAD). In the morphological investigation of the cells before apoptosis induction, there were no significant differences between the groups with regard to cell size and granularity of the MNCs. After apoptosis induction, the typical significant decrease in cell size and increase in granularity of the cells occurred in both groups. Significant differences between the patient populations were not found. For the first time, our investigation has demonstrated that a functional impairment of MNCs with regard to their apoptotic behaviour does not occur in sporadic CJD. It remains open to question whether this mechanism plays an important role in forms of transmissible encephalopathy other than sporadic CJD, especially after oral transmission.

Adult↗
PubMed2001

Sensitivity of titanium brackets to the corrosive influence of fluoride-containing toothpaste and tea.

Titanium brackets are used in orthodontic patients with an allergy to nickel and other specific substances. In recent studies, the corrosive properties of fluoride-containing toothpastes with different pH values were investigated. The present in vivo study tested how the surfaces of titanium brackets react to the corrosive influence of acidic fluoride-containing toothpaste during orthodontic treatment. Molar bands were placed on 18 orthodontic patients. In these same patients, titanium brackets were bonded on the left quadrants and stainless steel brackets on the right quadrants of the upper and lower arches. Fifteen patients used Gel Kam containing soluble tin fluoride (pH 3.2), whereas 3 used fluoride-free toothpaste. The brackets were removed for evaluation by light microscopy and scanning microscopy 5.5 to 7.0 months and 7.5 to 17 months after bonding. The quality and quantity of elements present were measured by scanning microscopy. Macroscopic evaluation showed the matte gray color of titanium brackets dominating over the silver gleam of the steel brackets. The plaque accumulation on titanium brackets is high because of the very rough surface. Pitting and crevices were observed in only 3 of the 165 brackets tested. The present in vivo investigation confirms the results of in vitro studies, but the changes are so minor that titanium brackets can safely be used for up to 18 months. Wing surfaces should be improved by modifying the manufacturing process.

Adult↗
PubMed2001

Kinematic analysis of handwriting movements in patients with obsessive-compulsive disorder.

OBJECTIVES: Basal ganglia dysfunction is supposed to play a part in the pathophysiology of obsessive-compulsive disorder (OCD). A new computer aided technique for the analysis of hand movements, allowing the detection of subtle motor performance abnormalities, was applied in this study of patients with OCD and healthy controls. METHODS: Using a digitising graphic tablet, hand motor performance was studied in 22 unmedicated patients with OCD and compared with 22 healthy controls. All subjects drew superimposed concentric circles with both the right and the left hand, in addition to writing a given sentence, their personal signature, and letter sequences in four different sizes. Kinematic parameters were calculated to quantify hand motion. RESULTS: Patients with OCD had significant impairments of handwriting performance, reflected by lower peak velocity (sentence t=3.6; p=0.001; signature t=2.8; p=0.01) and micrographia (sentence t=3.4; p=0.002; signature t=2.5; p=0.02), compared with controls and shortened acceleration phases per stroke (sentence t=2.4; p=0.02; signature t=4.1; p=0.000). By contrast, in repetitive drawing, patients with OCD had higher peak velocity than healthy controls (group x task interaction p<0.01). There were no significant differences in left and right hand performance between groups. Patients with early versus late age of onset differed in handwriting parameters, such as handwriting consistency. Greater severity of obsessions and compulsions correlated with increasingly poor handwriting performance in patients with OCD. CONCLUSIONS: A subtle motor dysfunction in OCD can be detected with a digitising tablet. The findings show handwriting impairments in patients with OCD, in line with the assumption that basal ganglia dysfunction is part of OCD pathophysiology. Repetitive motor pattern performance was not impaired, but rather tended to be even better in patients with OCD than in controls. The findings also support the concept that patients with OCD with early versus late age of onset differ in pathophysiological mechanisms and basal ganglia dysfunction.

Adolescent↗
PubMed2001

Patients with Alzheimer's disease and dementia with Lewy bodies mistaken for Creutzfeldt-Jakob disease.

OBJECTIVES: To describe the clinical presentation of patients with Alzheimer's disease (AD) or dementia with Lewy bodies (DLB) who were suspected of having Creutzfeldt-Jakob disease (CJD) and to investigate whether current clinical diagnostic criteria cover these atypical forms of AD and DLB. METHODS: Brains from necropsy were examined for the diagnosis of CJD at the German reference centre for spongiform encephalopathies. Symptoms and signs in patients with suspected CJD in whom necropsy showed AD (n=19) or DLB (n=12) were analysed. Their data were compared with a group of patients with CJD (n=25) to determine overlapping and discriminating clinical features. All patients were classified according to clinical diagnostic criteria for CJD, AD, and DLB. RESULTS: Demented patients were suspected of having CJD if disease was rapidly progressing and/or focal neurological signs appeared and/or an EEG showed sharp wave complexes. Myoclonus and limb rigidity were the most common neurological signs in all three dementias. DLB was not suspected in any patient, although patients with DLB showed parkinsonism (58%) and fluctuations (58%). Periodic sharp wave complexes (PSWCs) in EEG typical of CJD were found in five patients with AD and one patient with DLB. 14-3-3 Protein in CSF was detected in 20 patients with CJD, in two patients with AD, but not in any patient with DLB. Although most patients with DLB or AD met the clinical criteria for their respective diagnosis (74% and 90%), they also fulfilled criteria for CJD (42% and 58%). CONCLUSIONS: In patients with rapidly progressive dementia and focal neurological signs, CJD should be the first line diagnosis. Facing the triad dementia, myoclonus, and rigidity, AD should be considered if the disease course is longer and DLB is the differential diagnosis if parkinsonism or fluctuations are present. Findings on EEG or CSF typical of CJD do not exclude AD or DLB.

Alzheimer Disease↗