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Die moderne Schnittbilddiagnostik hat die Diagnostik des instabilen Sprunggelenks zuverlassiger, schonender und differenzierter gemacht. Hierbei ist die Sonografie fur den Kliniker unverzichtbar, wobei moderne High-resolution-Sonografiesysteme mehr Beachtung finden sollten. Die Magnetresonanztomographie kann einen vollstandigen Status der Gelenkstrukturen liefern. Durch neue 3D-Spin-Echo-Sequenzen ist eine hohe Kontrastauflosung bei isometrischer raumlicher Auflosung moglich. Lediglich fur die hochauflosende Diagnostik des Knochens, die Bestimmung der Mineralisation und die Arthrographie ist die Computertomographie (CT) als kongruentes Verfahren wichtig. Die CT-Fluoroskopie erleichtert und sichert die Gelenkpunktion. Die Strahlendosis kann auf 90 %. Gleiches gilt fur die Sehnen, die bei chronischer Instabilitat die „2. Verteidigungslinie“ des Halteapparats bilden.

BACKGROUND The liver has an excellent regenerative capacity after resection. However, below a critical level of future liver remnant volume (FLRV), partial hepatectomy is accompanied by a significant increase of postoperative liver failure. There is accumulating evidence for the contribution of bone marrow stem cells (BMSC) to participate in liver regeneration. Here we report our experience with portal vein embolisation (PVE) and CD133+ BMSC administration to the liver, compared with PVE alone, to augment hepatic regeneration in patients with critically low FLRV or impaired liver function. PATIENTS AND METHODS Eleven patients underwent PVE of liver segments I and IV-VIII to stimulate hepatic regeneration prior to extended right hepatectomy. In these 11 patients with a FLRV below 25% and/or limited quality of hepatic parenchyma, PVE alone did not promise adequate proliferation. These patients underwent additional BMSC administration to segments II and III. Two radiologists blinded to patients' identity and each other's results measured liver and tumour volumes with helical computed tomography. Absolute, relative and daily FLRV gains were compared with a group of patients that underwent PVE alone. RESULTS The increase of the mean absolute FLRV after PVE with BMSC application from 239.3 mL±103.5 (standard deviation) to 417.1 mL±150.4 was significantly higher than that from 286.3 mL±77.1 to 395.9 mL±94.1 after PVE alone (p

OBJECTIVE: Transmyocardial laser revascularization for angina relief and intramyocardial autologous endothelial progenitor cell injection for neoangiogenesis may offer a new treatment strategy for patients with intractable ischemic heart disease. METHODS: Transmyocardial laser revascularization and intramyocardial injection of bone marrow-derived CD133+ cells was performed in six highly symptomatic patients. Transmyocardial laser channels were created and isolated CD133+ cells were injected intramyocardially. All patients were followed up for a minimum of 6 months postoperatively. RESULTS: One patient died shortly after the operation due to refractory heart failure. In the five survivors, CCS class improved as well as left ventricular ejection fraction. Left ventricular end-diastolic volume and myocardial perfusion varied between the patients. All patients described a considerable improvement in quality of life postoperatively. Repeated 24-hour Holter monitoring revealed no significant arrhythmias. CONCLUSIONS: In this small patient cohort, intramyocardial CD 133+ cell injection combined with transmyocardial laser revascularization led to an improvement in clinical symptomatology in all patients and in left ventricular function in 4 out of 5 patients, with an unclear effect on myocardial perfusion. Caution is advised when employing this therapy in patients with severely depressed left ventricular function.

Die MRT des Kniegelenks bei Verdacht auf Erkrankungen des Meniskus gehort mittlerweile zum klinischen Standard. Die Untersuchung sichert die Diagnose und liefert dem Operateur zusatzliche Informationen uber die Kniebinnensituation. Lage, Grose und Struktur des Meniskusrisses sind darstellbar. Ferner ist ein begleitendes Knochenodem als Zeichen einer aktivierten Arthrose oder einer lokalen Ernahrungsstorung des Knochens erkennbar, wodurch das arthroskopische Vorgehen und die Nachbehandlung beeinflusst werden. Operateur und auch Patient werden bzgl. der Entscheidung/Indikation zum operativen Eingriff sowie der atiologischen Zuordnung von Beschwerden vor und nach dem Eingriff entlastet.

PURPOSE To evaluate the use of magnetic resonance imaging (MRI) compared with arthrography and arthro-CT (AG/ACT) in patients with wrist pain. METHODS MRI and arthrography/arthro-CT (AG/ACT) of the wrist joint were retrospectively evaluated in 346 patients over a three-year period. Imaging findings were correlated to surgical results (n = 78) or clinical course in an at least 6-month follow-up. RESULTS For tears of the triangular fibrocartilage, arthrography, arthro-CT, and MRI demonstrated a sensitivity and specificity of more than 0.96. Only the positive predictive value was superior for arthrography/arthro-CT (0.99 and 0.98, respectively) compared with MRI (0.94). Arthrography was superior for functional diagnosis of scapho-lunate ligament tears (n = 25). Ulno-lunate and ulno-triquetral ligament defects were demonstrated more exactly by arthrography. Traumatic osseous defects, particularly scaphoid fractures (n = 33) and avascular necrosis (n = 17), were better diagnosed using MRI. CONCLUSION For suspected lesions of the triangular fibrocartilage complex, AG/ACT is slightly more reliable than MRI. However, MRI was found to be highly accurate in diagnosing TFC tears, and is superior to AG/ACT in detecting traumatic and vascular lesions of the wrist.

The authors report about a 3-years experience with helical CT and 3-D surface reconstruction applied in neurosurgical patients. All examinations were performed in addition to preexisting diagnostic CT, MRI, or angiography. The aim of this study was to assess the clinical value of this method with regard to planning of the surgical approach to anterior, middle, and posterior skull base and spinal lesions. 75 examinations of 55 patients were analysed and ranked as follows: A = examination with significant additional information for neurosurgical planning of skull base or spinal procedures or for postoperative evaluation of the neurosurgical approach, B = examination with some useful information for the neurosurgical planning or postoperative control, however, without significant advantage as compared to established diagnostic methods, C = examination without significant additional information. Classification was performed independently by two experienced surgeons. Examinations of anterior, middle, and posterior skull base lesions including cerebral aneurysms were in the majority rated as helpful and significantly informative, (A = 21, B = 24, C = 9, n = 54). Three-dimensional imaging of the spine was of clinical value only in specific cases (A = 6, B = 6, C = 9, n = 21). The authors conclude that three-dimensional imaging is a valuable diagnostic tool for pre- and postoperative imaging of tumorous and vascular lesions adjacent to the skull base, allowing for optimal surgical approaches with minimal invasiveness.

The aim of the study was to determine whether the induction of HSP70 by Zn2+ is able to protect the small bowel of rats against ischemia. Twenty-four male Wistar rats (weight 200-300 g) were divided into four groups: (1) saline treatment for 24 h (n = 4); (2) Zn2+ treatment for 24 h (n = 4); (3) Saline pretreatment for 24 h and ischemia (n = 8); (4) Zn2+ pretreatment for 24 h and ischemia (n = 8). Pretreatment with Zn2+ was carried out by intraperitoneal administration of 50 mg/kg zinc bis (DL-hydrogen aspartate) = 10 mg/kg Zn2+. Ischemia in a defined segment of the small bowel was produced by ligation of the mesenteric vein and artery and ligation of both ends of the segment. Tissue samples were collected before and 2, 4 and 6 h after ligation and investigated by histology, immunohistochemistry and Western blotting. Twenty-four h after i.p. Zn2+ injection, the small bowel expressed increased HSP70 tissue levels. Histology with subsequent grading of ischemic tissue injury showed significantly decreased tissue necrosis after Zn2+ pretreatment and HSP70 induction compared with saline pretreated controls. In conclusion, this study proves that Zn2+ is inducing HSP70 in the small bowel in vivo and hereby able to protect the small bowel against ischemia.

To determine the value of diagnostic imaging in the management of mesenteric infarction.Within 8 years, 54 patients with mesenteric infarction underwent diagnostic imaging before surgery, including plain radiography (n = 45), ultrasound (US) (n = 29), small bowel follow-through examination (n = 7), colon enema study (n = 7), angiography (n = 16), and computed tomography (CT) (n = 22). Clinical course, laboratory values, and imaging findings were considered in diagnosis.Radiography and US allowed correct diagnoses in five of 18 cases (28%). Only one of 14 fluoroscopic examinations contributed to diagnosis. Fourteen of 16 angiography studies (sensitivity, 87.5%) and 18 of 22 CT examinations (82%) were correct. The difference in sensitivity between CT and angiography was not significant (P.05).CT and angiography are highly sensitive, but CT can also be used to rule out other causes of acute abdomen. Careful evaluation of patient history and clinical situation should lead to suspicion of mesenteric ischemia and early indication for CT.

Sprengel deformity is a congenital malformation with usually unilateral elevation and medial rotation of the scapula. An omovertebral bone is generally present. Associated skeletal malformations are frequently present. Though functional impairment is mild, the cosmetic and psycho-social impairment can be considerable. The prognosis of early surgical therapy is good. The presented case also justifies surgical correction in the older child.

We carried out 22 examinations to determine the value of three-dimensional (3D) volumetric CT (spiral CT) for planning neurosurgical procedures. All examinations were carried out on a of the first generation spiral CT. A tube model was used to investigate the influence of different parameter settings. Bolus injection of nonionic contrast medium was used when vessels or strongly enhancing tumours were to be delineated. 3D reconstructions were carried out using the integrated 3D software of the scanner. We found a table feed of 3 mm/s with a slice thickness of 2 mm and an increment of 1 mm to be suitable for most purposes. For larger regions of interest a table feed of 5 mm was the maximum which could be used without blurring of the 3D images. Particular advantages of 3D reconstructed spiral scanning were seen in the planning of approaches to the lower clivus, acquired or congenital bony abnormalities and when the relationship between vessels, tumour and bone was important.

The liver has an excellent regenerative capacity after resection. However, below a critical level of future liver remnant volume (FLRV), partial hepatectomy is accompanied by a significant increase of postoperative liver failure. There is accumulating evidence for the contribution of bone marrow stem cells (BMSC) to participate in liver regeneration. Here we report our experience with portal vein embolisation (PVE) and CD133+ BMSC administration to the liver, compared with PVE alone, to augment hepatic regeneration in patients with critically low FLRV or impaired liver function.Eleven patients underwent PVE of liver segments I and IV-VIII to stimulate hepatic regeneration prior to extended right hepatectomy. In these 11 patients with a FLRV below 25% and/or limited quality of hepatic parenchyma, PVE alone did not promise adequate proliferation. These patients underwent additional BMSC administration to segments II and III. Two radiologists blinded to patients' identity and each other's results measured liver and tumour volumes with helical computed tomography. Absolute, relative and daily FLRV gains were compared with a group of patients that underwent PVE alone.The increase of the mean absolute FLRV after PVE with BMSC application from 239.3 mL±103.5 (standard deviation) to 417.1 mL±150.4 was significantly higher than that from 286.3 mL±77.1 to 395.9 mL±94.1 after PVE alone (p0.05). Also the relative gain of FLRV in this group (77.3%±38.2%) was significantly higher than that after PVE alone (39.1%±20.4%) (P=0.039). In addition, the daily hepatic growth rate after PVE and BMSC application (9.5±4.3 mL/d) was significantly superior to that after PVE alone (4.1±1.9 mL/d) (p=0.03). Time to surgery was 27 days±11 in this group and 45 days±21 after PVE alone (p=0.02). Short- and long-term survival were not negatively influenced by the shorter waiting period.In patients with malignant liver lesions, the combination of PVE with CD133+ BMSC administration substantially increased hepatic regeneration compared with PVE alone. This procedure bears the potential to allow the safe resection of patients with a curative intention that would otherwise carry the risk post-operative liver failure.

The real-time expert system “Safety-Bag” is an integral part of the electronic railway interlocking system ELEKTRA. The interlockinh system contains a logic channel, which processes commands, and a safety channel, which checks the commands according to safety rules. Commands which are only allowed under certain circumstances are carried out only if the instructions generated by processing the command in the logic channel are checked and committed by the safety channel. To minimize the possibility of common errors in both channels, different programming paradigms are used. The logic channel is implemented in a procedural programming language and the Safety-Bag is implemented in PAMELA, a rule-based expert system language suitable for real-time applications. The rule-oriented programming paradigm is very well suited to the Safety-Bag because the safety requirements themselves are represented by rules. The Safety-Bag runs on a standard ALCATEL process control computer.

To evaluate the use of magnetic resonance imaging (MRI) compared with arthrography and arthro-CT (AG/ACT) in patients with wrist pain.MRI and arthrography/arthro-CT (AG/ACT) of the wrist joint were retrospectively evaluated in 346 patients over a three-year period. Imaging findings were correlated to surgical results (n = 78) or clinical course in an at least 6-month follow-up.For tears of the triangular fibrocartilage, arthrography, arthro-CT, and MRI demonstrated a sensitivity and specificity of more than 0.96. Only the positive predictive value was superior for arthrography/arthro-CT (0.99 and 0.98, respectively) compared with MRI (0.94). Arthrography was superior for functional diagnosis of scapho-lunate ligament tears (n = 25). Ulno-lunate and ulno-triquetral ligament defects were demonstrated more exactly by arthrography. Traumatic osseous defects, particularly scaphoid fractures (n = 33) and avascular necrosis (n = 17), were better diagnosed using MRI.For suspected lesions of the triangular fibrocartilage complex, AG/ACT is slightly more reliable than MRI. However, MRI was found to be highly accurate in diagnosing TFC tears, and is superior to AG/ACT in detecting traumatic and vascular lesions of the wrist.

The success of dental implantologic measures depends considerably on the correct positioning of the endosseous implants. A sufficient amount of bony substance is mandatory to provide overall covering of the implant with at least 1 mm of cortical bone. By the aid of a custom-developed software system, computed tomography image data can be handled on a conventional MS-DOS personal computer. The user is enabled to simulate size and positioning of the implant by interactive graphic animation. Quick and exact presentation is achieved by optimizing the computation algorithms. Storage needs are minimized by a segmentation procedure and additional compression of the image. Integrated patient data management and user friendly self-documenting program surfaces provide easy application.

Evaluation of CT cholangiography compared to i.v. cholangiography concerning its diagnostic value before laparoscopic cholecystectomy and optimisation of CT cholangiography.I.v. and CT cholangiographies of 54 patients were retrospectively evaluated by two radiologists. The time interval between contrast infusion and CT was correlated with the assessment of CT cholangiographies to detect the optimal timing for CT scanning.CT cholangiography was judged to be generally better than i.v. cholangiography. The optimal time interval for CT scanning is between 30 min and 60 min post contrast infusion.CT cholangiography should replace the conventional tomograms if i.v. cholangiography does not yield sufficient depiction of the biliary tree. It should be performed within 60 min post contrast infusion. Complete abolishment of i.v. cholangiography is not warranted. This is due to the fact that conventional cholangiography can sufficiently delineate the biliary tree and thereby reduce x-ray exposure and cost compared to initial performance of CT cholangiography.

Radiologists are able to visualize either structures of very different density or of different size. Their methods are limited to the determination of the thickness of the normal bowel wall or intramural gas collections and structures of 3–5 mm in thickness in a moving organ with peristaltic change of shape. It is not possible to visualize fibrous bands of less than 2 mm in thickness with a density that only differs by 5–10 HU from the surrounding enteric walls.

Mesenteric ischemia as an acute disease has a fatal outcome in about 60% of all patients [1]. Small intestinal ischemic necrosis occurs predominantly in elderly individuals with cardiovascular disease, artherosclerosis, and coagulative disorders [1, 2]. Intestinal damage occurs within minutes of total circulatory arrest, with the mucosa most sensitive to injury, followed by edema, hemorrhage, and sloughing. Within 1 h, the upper two thirds of the villi are denuded. If the blood supply is cut off for more than 2 h, the mucosa becomes progressively destroyed with subsequent development of transmural necrosis [3–5].

Objective : Our goal was to assess the value of CT and MRI for the detection of bowel wall changes in experimentally induced mesenteric ischemia. Methods : In 18 female pigs, a percutaneous embolization of the superior mesenteric artery was performed with buthyl-2-cyanoacrylate and Lipiodol (1 :1) (experimental group). In six animals, only diagnostic imaging and histologic evaluation were performed (control group). CT was carried out 3, 6, and 12 h after occlusion. Incremental CT (1 s scan time, 5 mm slice thickness, 7 mm increment, 120 kV/290 mAs) and spiral CT (slice thickness 5 mm, pitch 1.5, 120 kV/165 mA) were performed pre and post contrast injection (Somatom Plus/Siemens). Serial CT was carried out after intravenous contrast injection (1 ml/kg, 2 ml/s). MRI (Magnetom 1.5 T ; Siemens) was performed with T1 (pre and post 0.01 mmol/kg Gd-DTPA ; Magnevist ; Schering, Germany), T2, and proton density images in axial orientation. Slice thickness was 3 mm and slice gap I mm. Additionally, a T1-weighted GE sequence (multislice FLASH 2D) was obtained in dynamic technique (before and 30, 60, and 90 s after contrast agent injection) with a slice thickness of 5 mm. Biometrical monitoring included blood pressure, heart frequency, blood cell count, electrolyte status, blood gas analysis, and determination of serum lactate. Image evaluation included morphological analysis and determination of the enhancement pattern. Histological specimens were obtained and analyzed according to the Chiu classification. Results : The histologic workup of the specimen 3, 6, and 12 h after vascular occlusion revealed an average Chiu state 3, 4, and 5. On CT, the bowel wall had a thickness of 4.7 mm on average in the ischemic segments. There was a significant difference from the control group (average 3 mm). Free intraperitoneal fluid and intramural gas were seen after 12 h of ischemia in 80%. In ischemic bowel segments, no mural enhancement was seen. Normal segments and the bowel of the control animals showed an enhancement of 34 HU on average (SD = 3.1 HU ; p < 0.01). In MRI, S/N and C/N differed significantly between experimental and control groups in T1 and proton density images. In ischemic segments of all phases, the bowel wall did not show contrast enhancement. Healthy segments and bowel of control animals showed a significant enhancement (p < 0.01). Conclusion : Cross-sectional imaging has a high sensitivity for delineation of ischemic bowel wall segments. The enhancement pattern of the bowel wall enables detection of location, extent, and cause of a acute arterial mesenteric ischemia with high accuracy in an early phase.

The authors report their experiences gained from 19 patients with ventral or ventrolateral foramen magnum meningiomas operated on via the dorsolateral, suboccipital transcondylar access route. It is emphasized that the microsurgical management of these lesions includes two important aspects which increase the safety of the procedure: a meticulous preoperative planning based on the micro-anatomical details of each patient, as well as an individualized tailoring of the surgical approach. There were no deaths, and, in the past 5 years, no neurological complications in this series. Gross total removal of the tumour was achieved in each case. It is concluded that microsurgical removal of ventral or ventrolateral foramen magnum meningiomas with this technique constitutes a safe and recommendable procedure.

The authors report their experiences gained from 19 patients with ventral or ventrolateral foramen magnum meningiomas operated on via the dorsolateral, suboccipital transcondylar access route. It is emphasized that the microsurgical management of these lesions includes two important aspects which increase the safety of the procedure: a meticulous preoperative planning based on the microanatomical details of each patient, as well as an individualized tailoring of the surgical approach. There were no deaths, and, in the past 5 years, no neurological complications in this series. Gross total removal of the tumour was achieved in each case. It is concluded that microsurgical removal of ventral or ventrolateral foramen magnum meningiomas with this technique constitutes a safe and recommendable procedure.

Preoperative evaluation of any operating field is essential for the preparation of surgical procedures. The relationship between pathology and adjacent structures, and anatomically dangerous sites need to be analyzed for the determination of intraoperative action. For the simulation of surgery using three-dimensional imaging or individually manufactured plastic patient models, the authors have worked out different procedures. A total of 481 surgical interventions in the maxillofacial region, paranasal sinuses, orbit, and the anterior and middle skull base, in addition to neurotologic procedures were presurgically simulated using three-dimensional imaging and image manipulation. An intraoperative simulation device, part of the Aachen Computer-Assisted Surgery System, had been applied in 407 of these cases. In seven patients, stereolithography was used to create plastic patient models for the preparation of reconstructive surgery and prostheses fabrication. The disadvantages of this process include time and cost; however, the advantages included (1) a better understanding of the anatomic relationships, (2) the feasibility of presurgical simulation of the prevailing procedure, (3) an improved intraoperative localization accuracy, (4) prostheses fabrication in reconstructive procedures with an approach to more accuracy, (5) permanent recordings for future requirements or reconstructions, and (6) improved residency education.

To assess the value of computed tomography for the diagnosis of Crohn's disease and ulcerative colitis.We analysed the CT examinations of 109 patients with 197 involved bowel locations. 81 patients suffered from Crohn's disease, 28 from ulcerative colitis. Diagnosis was based on the combination of clinical, endoscopic and histopathologic findings. Three radiologists evaluated the CT series concerning the presence of morphologic changes analogous to conventional radiographic findings.In Crohn's disease, we found irregular outer contours in 26% of cases. The bowel wall was thickened in 82%. In acute phases, the bowel wall was thickened in 100%. Abscess and fistula as complications of inflammatory disease were present in 26 and 14% respectively. In ulcerative colitis, a target sign of the bowel wall was present in 40%, whereas in Crohn's disease a homogeneous wall density was present in all but two cases. Reduced attenuation due to submucosal fat deposits was found in 16% and mucosal tunneling in 27% of cases with ulcerative colitis. Even if severe mucosal destructions were found, the outer contour of the gut was smooth and regular in 95% of the ulcerative colitis cases.CT can provide additional information on acuity, extent and complications in inflammatory bowel disease. In combination with conventional radiographic findings a three-step classification for Crohn's disease and ulcerative colitis (early changes, acute and chronic phase) can be proposed.

The aim of our study was to determine the influence of ambient lighting conditions on the diagnostic performance when using digital reporting work-stations. We acquired 15 normal and 30 fractured porcine femurs using a storage phosphor system. All images were demonstrated on a high-quality image display under optimised (128 lx) and non-optimised (450 lx) ambient lighting conditions and on a conventional viewing-box under non-optimised conditions (450 lx). Results were analysed using ROC-statistics. The area under the ROC-curve was 0.895 for optimised conditions and 0.684 for non-optimised conditions using digital displays and 0.849 for the conventional viewing-box. The difference in diagnostic performance between optimised and non-optimised conditions using a digital display was highly significant (p0.001). Our results emphasise the importance of adequate surrounding lighting conditions for radiologic diagnostic performance, particularly for the use of digital reporting consoles.

The authors describe a method of real-time ultrasound-guided craniotomy for an approach to cerebral convexity lesions. During surgery, a specially designed high frequency (7.5 MHz) sector probe with a thin (11 mm), extended tip is used to image the cerebral lesion through a single burr-hole. The distance between burr-hole and lesion and the direction of the target are then determined from the ultrasound images, and craniotomy is completed with the aid of these parameters. Errors in the preoperative planning of the approach, which might result in incorrect placement of the craniotomy, can easily be recognized and corrected at an early stage of the operation, before the craniotomy has been completed. This technique greatly improves the accuracy in placing craniotomy flaps. Since the risk of misplacing the craniotomy is virtually eliminated in lesions which are identifiable on ultrasound images, the technique allows the surgeon to keep the skull opening as limited as possible.

RATIONALE AND OBJECTIVES A new technique was developed to achieve double contrast examinations in the small bowel without intubation. METHODS Effervescent granules and tablets were coated with an acid-resistant acrylic lacquer to provide selective enteric gas release. The coating thickness was 15% of dry weight for the granules and 1 to 4.5 mg/cm2 for the tablets. Fifty patients were examined using the method in a controlled study. All examinations were reviewed by two radiologists using a three-step quality score. The results were compared to 20 enteroclysis examinations. RESULTS Image quality was better for the coated tablets compared with the granules (P < .01). The double-contrast small bowel follow-through (DC-SBFT) provided a better quality examination in the terminal small bowel than in the jejunum. Enteroclysis yielded better results for the jejunum, but was not superior in the terminal ileum. Average time of fluoroscopy was 477 seconds for the DC-SBFT (n = 50) compared with 952 seconds for patients receiving enteroclysis (n = 528). No side effects or adverse reactions occurred due to contrast media application. CONCLUSIONS The results of this new method are preliminary, yet promising. For young patients and certain indications it may provide a less invasive alternative to enteroclysis.

Characterisation of focal liver lesions on computed tomography (CT) depends on correct interpretation of morphology and dynamic changes during bolus injection of contrast medium. The aim of this study was to develop a texture analysis concept for computer based interpretation of dynamic CT images. 148 focal liver lesions were investigated by serial CT. The study comprised 61 haemangiomas, 25 other benign lesions (FNH/adenomas) and 62 malignant lesions (primary or secondary). FNH, adenomas and malignant lesions were histologically proven. Diameter was 8-145 mm (mean 31 mm). Regions of interest were interactively defined. After extraction of characteristic textural features, a pattern classifier was trained. All CT series were evaluated using the "leaving-one-out" method. 134 of the 148 lesions were correctly classified (positive predictive value 0.9). Sensitivity for the presence of malignancy was 0.93 (80/86), specificity was 0.9 (56/62). False classification of a lesion was found to depend strongly on the quality of the examination (bolus intensity, positional change of the lesion due to respiratory movements).

Human bone segments of the toothed jaw were scanned using high-resolution CT with axial and coronal contiguous 1 and 2 mm slices. The bone segments were sliced analogous to the performed CT image positions. Contact films and micro-sections were made from the cuttings. Length and width of the teeth, the thickness of the alveolar bone and the distance between bone and dental surface were measured. Comparison of the CT measurements with contact films and histological specimen yielded best results for axial slices with 1 mm slice thickness (mean error 0.3-0.5 mm). Coronary oriented slices showed an error of 0.3-1.6 mm. 3D-reformatting can improve spatial orientation for axially produced image series. For CT imaging of the toothed jaw concerning the dento-alveolar structures, contiguous axial scanning with 1 mm slice thickness appears to be the concept of choice.

A human bone segment of the lateral maxilla was scanned using high-resolution computed tomography (CT) in contiguous parallel axis slices in order to image the topographical relationship between upper molars and the maxillary sinus. The bone segment was dissected analogously in 1 mm thick sections. After exposing contact films from these jaw cuttings, microsections were made for histological interpretation. The radiological-histological comparison between the CT-scans, contact films and the histologic specimens revealed absolute differences of 0.2-0.6 mm. The high resolution CT allowed an interpretation of details located between teeth and bone when the minimum bone thickness was 0.5 mm or more. First experiences with the CT-technique in orthodontic patients were promising, especially for the differential diagnosis of the dentoalveolar maxillary sinus relation.

Until now, bounds of model creation of medical objects had to be set because of the limited capabilities of available manufacturing equipment. Recently, stereolithography was developed as an alternative to current milling operations. In this process the surface of a photohardening liquid plastic compound is traced by a laser beam and hardened in layers. The models thus produced are extremely accurate and retain excellent detail. Specific implants can be designed and prepared as is illustrated in a case report. If tissue-compatible plastics are used, custom-made implants could soon be manufactured directly with the technique described.

Preoperative evaluation of the operating site is essential in planning surgical procedures. The relationship of pathology to adjacent tissues and vital anatomical structures needs to be analyzed to determine the intraoperative procedures required. For this the surgeon mentally simulates the procedure planned. For complicated conditions or reconstructive surgery in extensive bony defects, surgery can be simulated with three-dimensional reconstruction on either a monitor screen or on an individually manufactured plastic model of the patient. For this purpose different procedures for 3 D representation and manipulation of tomographic image data have been developed in our departments and the technique of stereolithography used experimentally to create custom-made plastic model of patients. A computerized video image manipulator was also developed for simulation of aesthetic plastic surgical procedures.

Techniques for 3D reconstruction of medical objects and production of models by CAM have been markedly improved. Milling tools have limited abilities to reproduce complex anatomical structures. Even if 5-axis milling systems are used, the problem of collisions between tool and object is not yet under control. An alternative is offered here by stereolithography. We performed a computed tomography (Somatom DRH, Siemens/Erlangen) of a child with extensive maxillary bone defect after surgical treatment of a congenital tumour. The bone defect was covered by an alloplastic implant. 3D reconstructions were performed by the aid of a conventional personal computer. Generated 3D volume data sets were transferred to a stereolithography system (3D Systems GmbH, Darmstadt/FRG). The produced model revealed high accuracy of the anatomical structures. Intraoperatively, the alloplastic prosthesis was removed and the shape of the new implant could be designed using the stereolithographic model.

The success of dental implantologic measures depends considerably on the correct positioning of the endosseous implants. A sufficient amount of bony substance is mandatory to provide overall covering of the implant with at least 1 mm of cortical bone. By the aid of a custom-developed software system, computed tomography image data can be handled on a conventional MS-DOS personal computer. The user is enabled to simulate size and positioning of the implant by interactive graphic animation. Quick and exact presentation is achieved by optimizing the computation algorithms. Storage needs are minimized by a segmentation procedure and additional compression of the image. Integrated patient data management and user friendly self-documenting program surfaces provide easy application.

The aim of this study was to evaluate the effect of chemotherapy on osteosarcoma by comparing the histologic pattern of primary tumors with that of their metastases. Therefore the primary tumors and metastases in 11 patients were macroscopically and histologically classified according to the Enneking and Broder systems as well as our own method. Three of 11 patients developed metastases with a less malignant pattern, 8 patients developed metastases which were as malignant as the primary tumor. The chemotherapeutics used had either an insubstantial effect or none at all on the differentiation of immature tumorous structures in the metastases and treatment did not lead to the expected improvement. Only the patients in whom, according to our own system, the primary tumors were classified as less malignant, are still alive.

To improve the planning phase for pediatric craniofacial surgery, 3D reconstructions of CT image series were performed on a personal computer. For construction of true models of the surgical site, two concepts were pursued. CT image data of six patients were used for model manufacturing by a conventional 2 1/2 axis milling system. The material used was polyurethane foam. Alternatively, in one patient a stereolithography was produced on the basis of the 3D reconstructed CT data. This new manufacturing device uses a photocurable monomer, hardened by a UV-laser. The spatial resolution of the system is about 0.1 mm. 3D-reconstructions were performed on a personal computer. Data were then transferred into a surface oriented structure to control a stereolithographic modeling device. Time for transfer was 70 min. The production of the modelled cranium took a total time of 59 h. Accuracy was found to be much higher in stereolithography than in milled models. The model served for surgical planning. The long time for production was caused by inadequate computer capacities, which are configured for much less complex objects in computer aided design. Furthermore the programs for the machine control are optimized for technical purposes. If these conditions are improved, stereolithography could be an attractive alternative to milling of medical models.

Conventional screen-film radiographs were compared with storage phosphorus images concerning diagnostic performance in traumatologic radiography. We used an image pool of 106 radiographs including 50 conventionally and 56 digitally recorded images. The images were reviewed by four experienced radiologists. Detectability of fractures was coded in a five-point scale of confidence and analysed by ROC statistics. Furthermore the image quality and the optical density was compared. Digital images are superior under difficult exposure conditions and offer advantages by additional image processing and documentation. For some indications (follow-up, functional examination), reduced x-ray exposure is tolerable. The detectability of subtle lesions, which is essential for the primary diagnosis of fractures was significantly better by conventional radiography.

The value of angiography is based on the fact that it enables the imaging of vascular processes (haemorrhage, aneurysm) and occasionally also the imaging of the vascular supply of tumors not related to any organ. Transarterial treatment procedures in the pelvic region, whether embolisation or intra-arterial chemoembolisation or intravasal radiotherapy, are on the whole rarely employed. They are important in palliative therapy of advanced and often inoperable neoplasms that cannot be treated otherwise. Transcatheter embolisation is an imhaemorrhages in the region of the a. iliaca int. or for arteriovenous malformations.

In this paper we discuss the theory that agoraphobic avoidances are central and spontaneous panics an epiphenomenon to the development of agoraphobia. Moreover we discuss the theory that posits a fixed cognitive-catastrophizing set as causal for panic. We conclude these theories do not fit the facts. We argue that it is important to distinguish between spontaneous panic and chronic or anticipatory anxiety and avoidance. Such a distinction allows for an understanding of the roles of anti-spontaneous panic medications such as tricyclics and MAOI's, as well as exposure therapy, in the treatment of panic disorder with agoraphobia. The former serves the purpose of blocking panic attacks while the latter undermines phobic avoidance, but only after the panic attacks have ceased through proper medication. We conclude that recognizing the key role of spontaneous panic and its variants in anxiety nosology is a necessary guide for etiological, psychophysiological and therapeutic research in this rapidly developing area.

It has previously been shown that, in patients with untreated progressive alopecia areata (AA), the peribulbar T4/T8 ratio is about 4:1. In the present study, the immunohistochemical findings obtained in untreated AA patients were compared to those obtained in patients who had received topical immunotherapy with diphencyprone. The untreated group consisted of 5 patients with progressive AA and 5 patients with inactive AA. The treated group consisted of 5 patients with a good response to diphencyprone and 5 patients with little or no hair regrowth after treatment. In untreated patients with progressive AA, the mean peribulbar T4/T8 ratio was 4:1, whereas in untreated patients with stable AA, the ratio was 2:1. In the treated patients with a good response to diphencyprone, the mean T4/T8 ratio was 1:1, while in the patients with poor or no response to treatment, the ratio was 0.7. In conclusion, topical immunotherapy considerably alters the peribulbar T4/T8 ratio in AA. The results are consistent with, but do not prove, the concept of topical immunomodulation.

In order to evaluate GnRH administration for the treatment of infertile men with elevated serum FSH levels we administered GnRH in pulses via portable electronic infusion pumps initially to seven patients with low sperm counts and high FSH values over 12 weeks and later to nine further patients over 24 weeks who also underwent testicular biopsies. Fifty microlitres containing 5 micrograms GnRH were infused subcutaneously for 1 min every 120 min in the short-term study and every 90 min in the long-term study. Although FSH levels could be lowered in both groups of patients, none showed any improvement in sperm count or other seminal parameters. Therefore, pulsatile GnRH treatment cannot be recommended for therapy of severe oligozoospermia with elevated FSH levels.

The commercial models of the Stallwood Jet are useful in controlling background, stabilizing arcs, and increasing the sensitivity of certain elements. However, these devices are generally awkward to use since the apparatus must be disassembled to change samples.