Early or localized forms of arrhythmogenic right ventricular dysplasia (ARVD) have been proposed as the arrhythmogenic substrate of repetitive monomorphic ventricular tachycardia (RMVT) originating in the right ventricular outflow tract in patients without any underlying cardiac abnormality on clinical examination and echocardiography. To further examine this hypothesis, magnetic resonance imaging (MRI) and signal‐averaged electrocardiography (SAECG) were performed on 23 patients with RMVT and normal 12‐lead standard ECG of conducted sinus beats. MRI was performed using ECG‐gated turbo spin‐echo images of the heart in order to detect signs of early or localized forms of ARVD, such as localized wall thickness reductions, signal intensity increase indicating adipose tissue infiltrates, and regional bulgings or aneurysms. MRI was normal in 22 (96%) of 23 study patients. In the remaining patient (4%), MRI demonstrated signal intensity increase in the intraventricular septum but not in the right ventricular outflow tract. Time‐domain analysis of the SAECG was normal in 21 (91 %) of 23 patients and revealed ventricular late potentials in 2 study patients (9%). Frequency‐domain analysis of the SAECG was normal in 22 (96%) of 23 patients and revealed ventricular late potentials in one study patient (4 %). We conclude that normal MRI findings of the heart and absence of ventricular late potentials in the SAECC in most patients with RMVT and otherwise normal ECG do not support the hypothesis that early or localized forms of ARVD create the arrhythmogenic substrate in the majority of these patients.

This paper describes a comprehensive approach for the assessment of the impact of (partial) Picture Archiving and Communication Systems (PACS). The approach is developed, based on actual clinical experience in three European hospitals and tested in these environments. The approach departs from a thorough analysis of the working procedures and information flows before implementation, both descriptive and quantitative. On the basis of this analysis, quantitative (and hence testable) objectives of the implementation are defined. The implementation strategy is defined after comparison of various scenarios, taking costs and effects for both the final and the transition phases into account. The approach is supported by a comprehensive evaluation protocol and a software package (PACER). The approach is demonstrated in this paper by applying it on a hypothetical PACS implementation for CT, ultrasound and for the part of the radiology department serving ICU. The objectives of this PACS are:(1)— to shorten the turn around time between the radiology department and ICU from 4 h to 30 min(2)— to save 2000 m2 of film per year and(3)— to save personnel time.In this case the PACS is introduced in three phases and completed after three years. The cost analysis shows that, if started in 1995, a financial break even point is reached after 6 years, when comparing costs for the film-based system with those of the PACS.Experiences in the three sites show that the approach helps to harvest potential benefits, allowing a cost-effective implementation of PACS.

BACKGROUND:Chronic subdural hematomas are well delineated collections of fluid (blood) between the dura mater and the arachnoid space. Two types of encapsulated chronic subdural hematoma can be distinguished: the nonseptated and the septated form. The nonseptated form can be treated easily using the burrhole-drainage method, whereas treatment of septated chronic subdural hematoma remains a therapeutical problem. The main problem is the division of the hematoma by neomembranes into compartments, which hinder the efflux of the hematoma fluid through one or two burrholes.METHODS:Since 1991 we have operated on 14 patients with septated subdural hematoma using flexible steerable endoscopes through a burrhole approach. The flexible endoscopes are fixed and guided with the help of the Marburg Neuroendoscopy Fixation and Guiding System. For resection of neomembranes small microscissors or microforceps were used. This technique avoids blunt rupture of the membranes which may cause bleeding. A closed drainage system is applied temporarily to guarantee the efflux of the remaining hematoma.RESULTS:From January 1991 to May 1994, 14 patients with the septated variant of chronic subdural hematoma were operated on using the endoscopic technique. After the neuroendoscopic intervention 12 patients had a sufficient or complete hematoma evacuation. One patient had to be operated on a second time, and there was one postoperative subdural infection. Long term follow up of all patients shows no recurrence of the subdural hematoma.CONCLUSION:Treatment of membraneous septated CSH using an endoscopic operative technique combined with the application of a closed drainage system is a minimally invasive method and a therapeutic alternative to the craniostomy-membranectomy technique.

Stereotactic endoscopic techniques are extremely helpful in diagnosis and therapy of cystic intracerebral space occupying lesions. Acute space occupying lesions can be managed effectively and without major tissue traumatization. Up to now we have operated on more than 70 cystic intracerebral space occupying lesions with a stereotactic endoscopic technique. The main diagnoses were colloid cysts, cystic craniopharyngeoma, arachnoidal and pineal cysts. In must be stressed that in cystic anaplastic astrocytomas and glioblastomas as well as metastases only an acute inner cerebral decompression can be achieved by neuroendoscopic techniques in combination with the application of reservoir systems. In benign parenchymal or intraventricular cysts neuroendoscopic intervention is performed for definitive treatment. The results are overall encouraging. There was no operative mortality and operative morbidity was below 3%. Postoperative follow-up in patients with benign cysts showed no evidence of recurrence.

Interstitial curietherapy with 125-Iodine is an effective therapeutic option in the treatment of low grade gliomas. Four cases with astrocytoma grade II are presented, where tumour growth characteristics have changed to anaplasia during interstitial irradiation after a primary period of tumour regression. Anaplastic transformation could be due to a radiation effect or an insufficient therapeutic influence of interstitial irradiation on natural tumour progression of glioma growth due to genetic events.

The purpose of the teleradiology project within the Marburg Image Management and Communication System (MIMACS) was to evaluate the teleconsultation process between the Departments of Diagnostic Radiology and Neuroradiology at the University Hospital of Marburg. The project was divided into three phases. In the first phase, completed in June 1992, the technical and organisational framework was developed. In the second phase, completed in October 1992, radiologists and neuroradiologists evaluated the functions of Siemens workstations DRC40 and Litebox by means of a questionnaire. It turned out that workstation functions most often used at both sites were: magnifying and rearranging images, displaying image data, using window/level presets and modifying the grayscale. Users rarely took advantage of the magic glass, zoom and density measurement functions. In the third phase of the study, the impact of teleconsultation on diagnoses and clinical recommendations was analysed. The study design included three radiologists who specified their diagnoses and clinical recommendations before and after consulting with the neuroradiologists. The degree of difference between these two points of judgement was evaluated by three radiologists who were not involved in the consultation process. The results of phase three show that teleconsultation changed the initial diagnostic findings in 34% of the cases and changed the clinical recommendation in 22% of the cases.

Within the EurIPACS HIPIN topic a generic HIS/RIS-PACS interface will be designed, implemented and evaluated. It is generally agreed that integration with the HIS/RIS is essential for the acceptance of PACS in a clinical environment. An interface between HIS/RIS and PACS allows more efficient usage of both systems, better integration of data, better consistency checking on shared data and better security and error handling. Also the PACS performance is improved by using HIS/RIS information to steer the image migration within the PACS. In this paper the functional specifications of the interface are described. These specifications are based on descriptions of clinical radiodiagnostic procedures. The generic interface consists of a common part, and of site specific adapters. The common part is identical for all incarnations and performs message scheduling, processing and logging. The adapters are specific for each communication standard, e.g. ACR-NEMA or HL7, and for each hospital. The interface will be implemented at the radiology department of the Philipps University Hospital in Marburg (Germany) and at the orthopaedic and neuroradiology departments of the hospital of the Free University in Brussels (Belgium).

Primary cerebral lymphomas are rare tumors. In the last years the frequency of these space occupying lesions is increasing. Diagnosis by image-generating methods is often difficult. Stereotactic biopsy is a reliable diagnostic tool. Explorative craniotomy with tumor resection should be avoided if possible. An effective multimodal therapeutic regimen is the combination of radiotherapy and chemotherapy. Epidemiologic data, diagnostic methods and therapeutic proceedings are presented and discussed on a series of 7 patients with primary cerebral lymphomas treated in our department.

The objective of the EurlPACS/HIPIN topic is to realize a generic HIS/RIS-PACS interface. The advantage of the generic interface concept is that it minimizes the efforts to realize a new instantiation of the HIPIN interface for a specific hospital. For a new instantiation only minimal adaptations in the software of the HIPIN interface itself and of the local HIS/RIS and PACS systems are required.

The IMACS installation in the Department of Diagnostic Radiology of the Marburg University Hospital has been used for improving case demonstrations in medical conferences and student teaching. Various items have proven to be advantageous: the cursor positioning, picture enlargement (magnifying — glass function) and the stack view for browsing through picture series (CT).

In open brain surgery, access to processes in the midline region is difficult. Exact diagnosis of the tumour type is crucial to the choice of therapeutic modality. In many cases, modern imaging procedures such as CT and MRI are useful diagnostic tools. The diagnosis is confirmed by direct biopsy and histological examination. Selected cases of tumours close to the midline (germinoma, pilocytic astrocytoma, primary cerebral malignant lymphoma) are presented. CT and MRI are helpful in demonstrating space-occupying processes. The tumour's histological type is determined by CT-stereotactic biopsy. The histopathological diagnosis is established by means of a crush preparation. Appropriate forms of therapy are proposed on the basis of the diagnosis of tumour type. The results are impressive, due to the efficacy of stereotactic procedures as an additional means of diagnosing and treating space-occupying processes of the midline region.

The recent development of broad-band communication technology and of image management and communication systems (IMACS) allows wider use of teleradiology applications. The history of teleradiology is briefly reported, evaluated and the state of the art discussed. Besides the fact that in most applications the transmission speed is still not sufficient, major reasons for limited progress are rather functional in nature. The teleradiology project of Marburg University is presented: the transmission of CT-scans between radiology departments of two hospitals and image transmission inside the main hospital complex. The hard- and software basis of the project is a Siemens IMACS connecting the two hospitals (3,5 km apart) with a glassfiber ethernet connection and linking different types of work stations and videoscreens into the IMACS network. The implementation of the system and detailed work flow analysis showed that the image system is even more influential on the traditional patterns of work flow than was the radiology information system which was introduced in 1987. The evaluation of the literature and of recent teleradiology projects as well as our own experience in the last two years prove that the introduction of teleradiology systems into the work flow of radiology departments is a major organisational undertaking for which most departments will lack appropiate manpower in quantity and quality.

In open brain surgery, access to processes in the midline region is difficult. Exact diagnosis of the tumour type is crucial to the choice of therapeutic modality. In many cases, modern imaging procedures such as CT and MRI are useful diagnostic tools. The diagnosis is confirmed by direct biopsy and histological examination. Selected cases of tumours close to the midline (germinoma, pilocytic astrocytoma, primary cerebral malignant lymphoma) are presented. CT and MRI are helpful in demonstrating space-occupying processes. The tumour's histological type is determined by CT-stereotactic biopsy. The histopathological diagnosis is established by means of a crush preparation. Appropriate forms of therapy are proposed on the basis of the diagnosis of tumour type. The results are impressive, due to the efficacy of stereotactic procedures as an additional means of diagnosing and treating space-occupying processes of the midline region.

The term "midline tumour" is defined partly from the topographic and from the pathogenetic point of view. Problems of modern imagegenerating procedures in establishing the diagnosis of cerebral midline lesions are described. The role of stereotactic diagnostic and therapeutic interventions is emphasized. Stereotactic brain tumour biopsy, installation of shunts and reservoirs under visual control are performed. Interstitial radiotherapy is carried out for low-grade gliomas. As an important innovation, stereotactic procedures are combined with endoscopic techniques. Particular diagnostic and therapeutic difficulties of typical midline tumours such as craniopharyngeoma, germinoma, glioma and primary cerebral lymphoma as a local extension are discussed. A reasonable concept in diagnosis and therapy of cerebral midline lesions is proposed.