[The value of magnetic resonance tomography (MRI) with reference to economic aspects of radiotherapy planning of vertebral metastases. A cost benefit analysis].

Is magnetic resonance imaging (MRI) based target volume definition for treatment planning of vertebral metastasis effective under economic considerations. From 1994 to 1999, a total of 137 patients with bone metastases affecting the vertebral column underwent MRI of the cervical, thoracic, or lumbar spine for the treatment planning of palliative radiation therapy. The following radiation treatment consisted in a irradiation of the affected vertebral region up to a total dose of 30-40 Gy.

[Sigmoidoperianal fistula associated with diverticulitis and Cul de Sac situation--diagnostics and therapy].

We report on the case of a 64-year-old female patient who presented herself in our outpatient clinic because of a perianal fistula with recurrent abscesses. We describe the step diagnostics and the surgical treatment of the causal sigmoido-perianal fistula with diverticulitis and Cul de sac situation. Clinical examination, fistulography, colonoscopy and MRT were part of the precise representation and preparation for the high anterior rectosigmoidal resection with simultaneous rectopexy according to Sudeck which were performed without complications.

KAMEDIN: a telemedicine system for computer supported cooperative work and remote image analysis in radiology.

The software system KAMEDIN (Kooperatives Arbeiten und MEdizinische Diagnostik auf Innovativen Netzen) is a multimedia telemedicine system for exchange, cooperative diagnostics, and remote analysis of digital medical image data. It provides components for visualisation, processing, and synchronised audio-visual discussion of medical images. Techniques of computer supported cooperative work (CSCW) synchronise user interactions during a teleconference.

Image transfer and computer-supported cooperative diagnosis.

The KAMEDIN system was designed as a low-cost communication tool as part of a computer-supported cooperative work project that included synchronized user interaction, telepointing and audioconferencing. During a five-month field trial, it was used for medical image transfer and cooperative diagnosis in 14 clinics and medical departments in Germany. During the field test, 297 teleconsultations were performed via ISDN and 875 MByte of data were transferred.

[Digital picture archiving, processing and communication in diagnostic imaging with a Siemens Network (SIENET): initial results].

The concept of Picture Archiving and Communication System (PACS) in digital imaging offers substantial advantages: better data security, faster access to archived images, simultaneous availability of images at different sites, minimal space demand for archive medium, retrospective image post-processing opportunities and lower costs resulting from reduced film consumption and length of stay. However, practical experiences concerning reliability and efficiency of real PAC networks in radiological departments have to be made yet in order to improve network structure, software design and hardware performance. The ongoing stepwise installation and test of a Siemens PACS (SIENET) at the Department of Radiology at the Medical University of Lübeck will support the introduction of PACS concept into radiological practice.

ISDN based teleradiology and image analysis with the software system KAMEDIN.

This contribution describes the software system KAMEDIN (Kooperatives Arbeiten und MEdizinische Diagnostik auf Innovativen Netzen) that is designed as an ISDN based computer supported cooperative work (CSCW) tool for usage in medical diagnostics. Medical image data from various sources (for example CT and MR) can be interchanged and analyzed in bilateral teleconferences via ISDN. During a cooperative session, user interactions for image processing etc.

Insufficient hemodialysis access fistulas: 18 months' experience in laser-supported dilation.

Patients with end-stage renal failure disease frequently develop venous stenoses or occlusions in their hemodialysis access fistulas caused by intimal fibrosis. A complete dilation with high pressure balloons up to 20 atm may be unsuccessful in those cases. We investigated two new pulsed dye laser devices for the ablation of obstructions, which were not adequately treatable with a previous balloon angioplasty.

Neural network approach for computer-assisted interpretation of ultrasound images of the gallbladder.

Multi-formatted films of 90 ultrasound examinations of the gallbladder (stones 56 cases, sludge 20 cases, hydrops five cases, normal gallbladder nine cases) have been digitalized and stored in a personal computer. Image data of each examination was processed to extract a 19-dimensional vector that represents the essential diagnostic information of each examination. This vector was evaluated by three different classification algorithms: (1) classical nearest neighbor principle, (2) classical linear discriminant analysis, (3) multilayered backpropagation neural network.

[The laser-assisted balloon angioplasty of insufficient hemodialysis-access fistulae].

Patients with end-stage renal failure frequently develop venous stenoses or occlusions in their haemodialysis access fistulas caused by intimal fibrosis. A complete dilation with high pressure balloons up to 20 atm may be unsuccessful in such cases. We investigated two pulsed dye laser devices for the ablation of obstructions, which were not adequately treatable with a previous balloon angioplasty.

[Thrombotic and thromboembolic occlusions of leg arteries and bypasses. Short-term versus long-term lysis].

Since thrombolytic therapy is less invasive than operative thrombectomy, it is often used as initial treatment for thrombotic or thrombo-embolic occlusions of lower limb arteries or by-passes. We compared four patient groups with acute and subacute occlusions: 1. 19 patients with occluded by-passes treated by rapid lysis using 15.

Follow-up study of renal transplants by duplex Doppler and gray-scale ultrasound.

In the early postoperative period after renal transplantation 388 follow-up ultrasound examinations were performed in 77 patients. Over a period of 18 months standardized duplex indices (resistive index, pulsatility index) and gray-scale parameters (parenchyma/sinus index; medulla/cortex index) were sampled. These data were correlated retrospectively with clinical and pathological diagnoses.

Non-absorbable fat-dense oral contrast agent for abdominal computed tomography.

Opacification of the gastrointestinal tract for CT scanning is usually achieved by oral administration of a diluted iodine solution or barium suspension. As high-density contrast agents often cause image degrading artifacts, we investigated the value of a paraffin-methylcellulose emulsion as an oral CT scanning agent. Diseases of the intestinum were clearly outlined with paraffin emulsion, and image degrading artifacts were virtually not encountered.

Initial clinical experience with a new pulsed dye laser device in angioplasty of limb ischemia and shunt fistula obstructions.

Selective plaque ablation with laser radiation at 405-530 nm in vitro has been reported. We investigated the possibilities of a new pulsed dye laser device for in vivo recanalization of arteries in ischemic lower limbs and stenoses/occlusions of arterio-venous hemodialysis shunt fistulae. A specially designed 9F or 7F multifiber catheter was used for treatment of 10 patients with lower limb artery obliterations and 11 patients with malfunctioning hemodialysis access fistulae (HAF).

[Imaging diagnosis of parotid diseases--a comparison of methods].

Thirty-five patients with parotid gland disorders were ultrasonographically examined with a "small parts" scanner, as well as with high-resolution computed tomography, and conventional and digital subtracted sialography. The results were compared with clinical, surgical, and pathomorphological data. In cases of parotid gland masses, the sensitivity of sonography, CT, and sialography was 100%, 81%, and 70% respectively, while in cases of sialadenitis, sensitivity was 38%, 50%, and 75%.

[Selective catheter angiography using a translumbar technic].

By using a new 5-F-needle-sheath system for translumbar aortic puncture, it was possible to introduce 4-F-catheters of different lengths and shapes. In nine patients 19 vessels were selectively catheterised. There were no complications.

Digital subtraction sialography, conventional sialography, high-resolution ultrasonography and computed tomography in the diagnosis of salivary gland diseases.

Forty-one patients with salivary gland disorders have been evaluated by digital subtraction sialography, conventional sialography, high-resolution ultrasonography and computed tomography, and the results compared with clinical, surgical and pathomorphological data. In the case of salivary gland masses, the sensitivity of ultrasonography, CT and digital subtraction sialography was 100%, 82% and 71%, respectively, while in the case of sialadenitis, the respective figures were 54%, 69% and 85%. The image quality of digital subtraction sialography was superior to that of conventional sialography in 80%, equal in 16%, and inferior in 3% of the examinations.

Insufficient hemodialysis access fistulas: late results of treatment with percutaneous balloon angioplasty.

Forty-six patients with malfunctioning hemodialysis access fistulas were treated with balloon angioplasty. The initial percutaneous transluminal angioplasty procedure was successful in 16 (89%) of 18 patients with stenoses and in 13 (46%) of 28 with occlusions. In ten patients (seven with stenoses and three with occlusions) repeated dilation (two to five times; mean, two times) became necessary due to recurrent malfunction 1-24 months (mean, 6 months) after the first intervention.

[MR tomography of the elbow joint].

MR examinations of the elbow joint of three healthy subjects and a comparison with corresponding sections of anatomical preparations show that MR tomography enables not only an excellent differentiation of muscles, tendons and of the articular capsule, but will also visualise vessels and nerve tracts. MR tomography proved superior to the conventional methods in demonstration of separate fragments and inflammatory changes in the bone on examining 11 pathological elbow joints: congenital malformation, osteochondritis dissecans, ostitis, ulnar and radial nerve lesions, completely healed radius fracture and epicondylitis of the radial and ulnar humerus. Epicondylitis could not be demonstrated by MR.

Arterial bolus curve after intravenous injection of ionic and nonionic contrast media.

Studies of the intra-arterial bolus curve after intravenous contrast injection with dynamic computed tomography show that a higher bolus maximum can be obtained with a central injection than with a peripheral injection, other injection parameters remaining unchanged. In a singular venous injection ionic and nonionic contrast media show no different effects on the bolus curve. Due to the unfavorable effects of ionic contrast media with high osmolality, for the purposes of intravenous digital substraction angiography nonionic contrast media must be recommended.

Translumbar catheter angiography with a needle-sheath system.

Translumbar catheter angiography with a new needle-sheath system was used in 175 patients and proved to be a safe and simple technique. No complications related to aortic puncture or catheter manipulation were observed. The 5-F sheath allowed the introduction of 4-F catheters of different lengths and shapes.

[Digital subtraction dacryocystography].

A comparison of 17 radiological examinations of the lacrimal pathways performed on twelve patients using digital subtraction and conventional film technique showed that digital subtraction dacryocystography yields images of superior quality. Digital subtraction makes enhanced imaging of the opacified tear duct as well as elimination of super-imposing skeletal structures possible, which with conventional techniques frequently impair diagnostic accuracy. In measurements of the radiation dose sustained by the crystalline lens, the radiation level with digital subtraction was found to be considerably lower than with the conventional method.

[Digital subtraction sialography].

In 22 patients we performed 33 sialographies of salivary glands using digital subtraction technique as well as conventional technique (100 mm camera). In the majority of cases the digital subtraction technique was superior to the conventional technique regarding diagnostic image quality. Additionally, digital subtraction technique generally needs a lower number of contrast media application.