Evaluation of surface and volume rendering in 3D-CT of facial fractures.

OBJECTIVES: Three-dimensional computed tomography (3D-CT) of facial fractures has been reported as beneficial using surface (SR) and volume rendering (VR). There are controversial statements concerning the preferable algorithm. The purpose of this study was to evaluate and compare SR and VR for clinical 3D-CT in facial fractures on an experimental basis. METHODS: Multislice CT was obtained in 22 patients with facial fractures using two data acquisition protocols. Five SR and VR post-processing protocols were applied. Five assessors independently evaluated the quality of visualization of the fracture gap and dislocated fragments as well as the overall image quality using a five-point rating scale. The potential benefit of the 3D-images for radiological diagnosis and presentation was evaluated. The influence of the data acquisition protocol was analysed. RESULTS: SR in general achieved better evaluation scores than VR at corresponding thresholds. Variation of evaluation scores for all criteria was found for SR and VR depending on the segmentation threshold. Apart from the overall image quality no significant influence of the data acquisition technique was found for the evaluated criteria. CONCLUSIONS: SR provided sufficient and time efficient means for 3D-visualization of facial fractures in this study. No diagnostic benefit of VR over SR was found.

Age-dependence of cerebrospinal parameters.

OBJECTIVE: The records of 159 patients were reviewed who routinely underwent a classical volume-pressure testing procedure due to suspected cerebrospinal fluid circulatory disorders. METHODS: Regression analyses were carried out to explain the cerebrospinal parameters' relationships to age. Least median squares (LMS) algorithms achieved robust estimation of simple linear model parameters. Also, method of weighted regression was used because of unequal variances in the observations. RESULTS: Cerebrospinal elastance and resistance to outflow revealed significant LMS regressions: y = 0.171x + 7.460 (n = 159, p < 0.0001) and y = 0.096x + 1.871 (n = 97, p < 0.0001), respectively. Similarly, weighting data resulted in models such as y = 0.151x + 6.830 (p < 0.0001) for elastance and y = 0.087x + 1.730 (p < 0.0001) for resistance estimates. The intracranial pressure at rest showed no age-related dependency. Both clear clinical and morphological signs were found in 20% of patients. CONCLUSION: Expecting no time-variant properties we surprisingly found a significant linear relationship in cerebrospinal parameters and age. Thus, parameter magnitudes are not likely dominated by a pathological process only but also determined by temporal system alterations.

[Multisegmental image fusion of the spine]. / Mehrsegmentale Bildfusion an der Wirbelsäule.

Fusion of medical images is a technique that permits the correlation of homologous anatomical structures in different imaging modalities on the basis of a spatial transformation of the data sets. CT and MRI of the spine provide complementary information of possible relevance for diagnostic and therapeutic decisions. Methods enabling a multisegmental CT-MRI fusion of the spine were developed. These solve the problem of altered spatial relationships of the individual anatomical structures due to differing patient positioning in successive data acquisitions. Routine clinical CT and MRI data of a thoracic section of the spine were obtained and transferred to a PC-workstation. Following segmentation of the CT-data, landmarks for each individual vertebra were defined in the CT and MRI data. For each individual vertebra the algorithm we developed then carried out a rigid registration of the CT information to the MR data. The fused data sets were presented as colour-coded images or on the basis of dynamic variation of transparency. To assess registration precision, fiducial registration errors (FRE) and target registration errors (TRE) were calculated. The algorithm permitted multi-segmental image fusion of the spine. The average time required for defining the landmarks was 22 seconds per landmark for CT, and 34 seconds per landmark for MR. The average FRE was 1.53 mm. The TRE for the vertebrae was less than 2 mm. The colour-coded images were particularly suitable for assessing the contours of the anatomical structures, whereas dynamic variation of the transparency of overlapping CT images enabled a better overall assessment of the spatial relationship of the anatomical structures. The algorithm permits precise multi-segmental fusion of CT and MR of the spine, which was not possible using current fusion-algorithms due to variations in the spatial orientation of the anatomical structures caused by different positioning of the axial skeleton in successive examinations.

[Development of a universal interface for the exchange of medical image data using magneto-optical media]. / Entwicklung einer universellen Schnittstellenumgebung zur Ubertragung medizinischer Bilddaten mit magnetooptischen Medien.

Digital images generated by medical imaging form the basis for radiological diagnosis and surgical planning. Despite the advent of the DICOM 3.0 standard for medical image communication, widespread application of the existing information is often limited by incompatibility of the data formatting used by different equipment generations, and the manufacturer-specific standards employed. An exchange interface based on magneto optical discs has been developed to retrieve and present medical image data regardless of the technological hardware and the specific formats used. Specially adapted routines to retrieve the data first had to be developed. A modular program structure was used to allow flexibility in the implementation of further routines and other exchange media. Over 20,000 CT and MRI images including header information obtained from different General Electric and Siemens scanners were extracted successfully from MO discs. The image data were used for follow up and surgical planning and were transferred to a PAC-server. The interface proved reliable and easy to use. Support for further proprietary formats is currently being developed. The present exchange interface permits reliable retrieval of digital images for diagnostic and surgical planning purposes, regardless of the hardware generation and manufacturer-specific formats.

Artificial elevation of brain tissue glycerol by administration of a glycerol-containing agent. Case report.

In recent years the development of secondary brain damage and derangement of neurochemical parameters after severe head injury has been monitored using microdialysis. Provided the blood-brain barrier is intact, glycerol is regarded as a potential marker for membrane phospholipid degradation. The authors report a case in which marked elevation of interstitial glycerol was induced after exogenous administration of a glycerol-containing agent. A 25-year-old man was injured in a motorcycle accident and was admitted to the authors' institution with a unilateral dilated and fixed pupil and a Glasgow Coma Scale score of 3. Computerized tomography scans revealed a large subdural hematoma on the left side, subsequent midline shift, and generalized edema. Emergency craniotomy was performed for evacuation of the hematoma. The patient was prepared for multisensory monitoring and a microdialysis catheter was inserted into his left frontal lobe. After a routine enema containing 85% glycerol had been administered, the authors measured a marked increase in glycerol in the dialysate. This occurred while the patient was in as stable a condition as could be expected given the circumstances. The increase in interstitial glycerol in the injured tissue was most likely due to an impaired blood-brain barrier. Thus, the interstitial glycerol concentration had been corrupted by exogenous glycerol, and the marker properties of glycerol in this case became questionable. Consequently, administration of glycerol, which is frequently found in various infusions and emulsions, can promote secondary brain damage by adversely shifting osmotic gradients.

Cerebral blood flow in chronic hydrocephalus--a parameter indicating shunt failure--new aspects.

Prediction of outcome after shunt-therapy in chronic hydrocephalus syndrome is uncertain. Pathology reveals an impairment of cerebral blood flow (CBF). Based on this, we evaluated CBF and its significance for the assessment of prognosis. In 21 patients (mean age 69 years) selected for surgery, CBF was measured by PET (15O-H2O) before, about one week and 7 months (n = 14) after shunting. CBF was computed by a 1-compartmental model in the territories of the ACA, MCA and PCA. One PET slice in the height of the maximum projection of both cellae mediae was chosen. CBF data were standardized by cluster analysis. Three CBFClusters with significantly different CBF levels prior to shunting in the ACA, MCA and PCA territory, respectively, referred to the sample average (38.2 ml/100 ml/min) were found. These CBFClusters differed in clinical outcome: almost 50% and 90% of patients improved clinically in CBFCluster I, with a perfusion level lower than average, after one week and 7 months, respectively. In contrast, patients of CBFCluster II with an average perfusion did not improve. CBF changes 7 months after shunting related to global CBF before surgery showed a relationship with the clinical course. Clinical outcome corresponded with preoperative global CBF values. Cerebral blood flow lower than average forecasts clinical improvement. Our results suggest that measurement of CBF adds to the indication for surgery.

[Preserving and improving the profile in primary and secondary orbital reconstruction]. / Profilerhalt und -verbesserung bei primärer und sekundärer Orbitarekonstruktion.

Computed tomographies in 15 patients following reconstruction of multiple-wall defects of the orbit following trauma and tumor demonstrate a correlation between moderate overcorrection of the orbital bony frame and a good aesthetic profile. Reconstruction of the deep orbital cone, the transition level between the orbital floor and medial orbital wall, as well as the convex shape of the medial orbital wall, are of great importance for good results.

[Treatment outcome in patients with chronic subdural hematoma with reference to age and concurrent internal diseases]. / Behandlungsergebnisse bei Patienten mit chronisch subduralem Hämatom unter Berücksichtigung des Alters und internistischer Zusatzerkrankungen.

The chronic subdural hematoma (CSH) is a disease in elderly patients beyond the 5th decade. Treatment of CSH is normally a burr hole trephination and subdural drainage. Although this technique is simple, lethality is reported to be up to 20% in literature. The records of 314 patients with CSH were analyzed. Attention was focussed on complicating diseases and distribution of age. Patients were categorized neurologically before and after trephination using the Bender scale. The portion of patients suffering from cardiological diseases was 14.3%, 6.7% were treated by anticoagulants because of cardiac valve implant. Alcoholics were found in 15.9% of patients and hypertension in 12.8%. Complicating diseases were found in 51.3% of patients. Multiple internal diseases are likely to affect prognosis more than hematoma thickness. These patients also brought about a higher rate of infection (4.8%), secondary hemorrhages (2.5%), pneumonia (3%) and seizures (5%) after trephination. Lethality was highest in patients with diabetes mellitus, cardiogenic diseases and hypertension as well as in elderly patients. The latter have also a poor post-operative outcome: 22 patients died. In contrast to hematoma thickness and midline shift, which do not have any influence on outcome, prognosis is mainly determined by age, complicating diseases, hypertension and diabetes mellitus. The chronic subdural hematoma is often found in multi-morbid patients.

On the effect of calcium antagonists on cerebral blood flow in rats. A comparison of nimodipine and flunarizine.

To assess the influence of nimodipine treatment in brain tissue at different levels of blood pressure, we estimated the cerebral blood flow using hydrogen clearance. Rats were treated with nimodipine (n = 8), its placebo (n = 10), flunarizine (n = 11) and its placebo (n = 10), and a group of controls (n = 10). Cerebral blood flow was estimated during arterial normo-, hyper- and hypotension. The lowest cerebral blood flow estimates calculated for nimodipine were 43.8 +/- 7.8, 90.9 +/- 13.3, and 33.6 +/- 6.1 ml/min/100 g for normo-, hyper- and hypotension, respectively. Cerebral blood flow in the nimodipine placebo group was 84.1 +/- 10.3, 139.9 +/- 19.9, and 55.2 +/- 10.5 ml/min/100 g. In the flunarizine group, the blood flow was 77.3 +/- 15.2, 144.7 +/- 15.0, and 43.8 +/- 5.9 ml/min/100 g. In the control group, cerebral blood flow was 90.0 +/- 29.1, 143.0 +/- 42.1, and 75.5 +/- 29.8 ml/min/100 g. The low blood flow in the nimodipine group might have been a consequence of brain edema caused by extravasates. Thus impaired blood flow reduces the usefulness of nimodipine in the prevention of vasospasm. Flunarizine is a potential alternative treatment of vasospasm treatment as well as for cerebral blood flow improvement, as shown in our experimental study.

Computed tomographic criteria and survival rate for patients with acute subdural hematoma.

OBJECTIVE: Computed tomographic data from 174 patients with acute subdural hematoma were analyzed statistically to identify parameters that could be evaluated independently of clinical and neurological status to estimate outcome. METHODS: This retrospective study was made necessary by the fact that the patients admitted usually had been treated with intubation, sedation, and artificial ventilation, which precludes neurological examination. RESULTS: In surgically treated patients, the hematoma thickness ranged from 5 to 35 mm and the midline shift was 0 to 33 mm. In 81 patients (46.6%), the hematoma thickness was greater than the midline shift; in 24 patients (13.8%), the hematoma thickness equaled the midline shift; and in 69 patients (39.6%), the midline shift exceeded the hematoma thickness. Of the patients, 52% died after surgery, for 29% we obtained good or satisfying results, and 19% were in poor condition after therapy. The Kaplan-Meier survival analysis proved that the survival rate was only 50% for a hematoma thickness of approximately 18 mm and a midline shift of 20 mm. The survival function dropped markedly for midline shifts of more than 20 mm and converged to 0% for midline shifts of more than 25 mm. If the midline shift exceeded the hematoma thickness by 3 mm, the survival function was 50%; when the midline shift exceeded the hematoma thickness by 5 mm, the survival function was 25%. The Glasgow Outcome Scale scores were correlated significantly with these parameters. The parameters, which are the measured hematoma thickness, the midline shift, and the difference between the hematoma thickness and the midline shift, allow robust/adequate estimation of survival function and outcome for patients suffering from acute subdural hematoma. CONCLUSION: Based on these data, indications for surgery could be assessed by means of video conferencing, i.e., without personal examination of the patients.

Ultrastructural changes in the blood-brain barrier in rats after treatment with nimodipine and flunarizine. A comparison.

The idea of using induced hypertension to treat the symptomatic ischaemia resulting from vasospasm after subarachnoidal hemorrhage, and the effect of this therapy on the blood-brain barrier, is checked in animal experiments. This therapy is combined with the application of nimodipine, which is recognised as the standard medication for prophylaxis of vasospasm. The effects of the induced hypertension combination with Nimodipine and in combination with another calcium antagonist, Flunarizine are compared. Seventy-four narcotised rats, one group with 22 animals treated with Nimodipine and 22 with placebo, and a second group 20 animals treated with Flunarizine and 10 with placebo, are evaluated. The blood pressure is raised to 150-180 mmHg by i.v. application of norfenephrine and measured continuously. The standard tracer, horseradish peroxidase, is applied as indicator for the blood-brain barrier function. 15 minutes later the experimental animals are exsanguinated by perfusion with saline, then perfused with Karnovsky's solution. After removal, the brains are stained for peroxidase to visualise extravasation of the horseradish peroxidase, and after evaluation of the results each brain is assigned to its experimental group. In the Nimodipine group, a significant accumulation (p < 0.001) of perivascular deposits of peroxidase reaction product were found, these were not found in the placebo group. The Flunarizine group does not differ from its placebo group in the number of extravasates, and thus, with respect to protein extravasation, appears better than the Nimodipine group. In electron micrographs of the extravasates one sees intact tight junctions and a neuroendothelial transport, and also vesicles, filled with horseradish peroxidase in the endothelium, the muscle cells, and the brain parenchyma, which arise from pinocytosis. The vesicles, which transport the high-molecular-weight protein, horseradish peroxidase, also transport other proteins and can, therefore, cause a brain edema. It follows from these morphological results that Nimodipine can disrupt the blood brain barrier function and can, therefore, also interfere with cerebral autoregulation, which depends on the resistance of vessels.

[Multiple meningiomas in different compartments of the cerebrospinal axis]. / Multiple Meningeome in verschiedenen Etagen der zerebromedullären Achse.

Multiple meningeomas in the absence of Recklinghausen's disease are rare and usually occur in a single compartment of the neuroaxis. Multiple meningeomas in different neuroaxial compartments are an even rarer condition, only a few cases having been reported. We describe four cases, each with two meningeomas in different compartments of the neuroaxis. Their peculiarity consists in the fact that the different tumours developed at different times and locations in the supratentorial and spinal regions. The radiological and operative findings are described. The possibility of dissemination via the cerebrospinal fluid or blood or of a multifocal origin or genetic predisposition is discussed.

Vasospasm after experimentally induced subarachnoid haemorrhage and treatment with nimodipine.

At day one and on the following day subarachnoid haemorrhage (SAH) was induced in SPF-rats by injection of a mixture of autologous blood and CSF into the cisterna magna. At day eight the animals were treated with Nimodipine. Extracellular calcium and -potassium concentrations as well as local cerebral blood flow and arterial blood pressure were measured simultaneously. The cerebral vasospasm was documented by corrosion casts. The control group underwent the same procedure without previous SAH. Cerebral vasospasm still exists after nimodipine infusion as it can be demonstrated by corrosion casts showing an intensive grooving and a vertical relief. Extracellular potassium and calcium concentration are higher in the SAH-group than in the control-group. The influence of nimodipine to blood pressure and cerebral blood flow is more impressive in rats with SAH showing a significant decrease in blood pressure and local blood flow.

The results of surgery for intracerebral hematomas.

Our retrospective study included 104 patients (28 female and 76 male) with intracerebral bleeding, treated between 1978 and 1988 in the Neurosurgical Clinic of the Medical University in Hannover. The average age was 43 years. 53 patients presented with traumatic intracerebral bleedings, and 51 with spontaneous hematomas. 31 patients with spontaneous hematomas were operated: among these a good or satisfactory result was obtained in 19 patients, and 12 died. Of the 20 non-operated patients, a good or satisfactory result was achieved in 10. 31 patients were operated in the group with traumatic hematoma, of these 22 had a good or satisfactory outcome and 9 patients died or had an unsatisfactory result. Of the 22 non-operated patients, 13 died and 9 achieved a good or satisfactory result. In the stratified Chi2-Test the effects of the operation were not found to be significant, with 0.1 less than p less than 0.25 for spontaneous, and 0.25 less than p less than 0.05 for the traumatic hematomas. There is a trend in favor of the operation in certain cases.

Ultrastructural changes in the blood-brain barrier after nimodipine treatment and induced hypertension.

Fourty-four narcotized rats were split into two equal groups, one being treated with nimodipine and the other with a placebo. By use of norfenefrine the blood pressure was raised to values of 150 and 180 mm Hg within the limits of the autoregulation of brain perfusion and under continuous measurement. Fifteen minutes after application of the standard tracer, horseradish peroxidase, the animals were exsanguinated using a saline perfusion and then perfusion-fixed with Karnovsky's solution. After development of the peroxidase staining the brain sections were evaluated and then allocated to their respective groups. In brain tissues from the experimental group significantly more frequent perivascular accumulations of horseradish peroxidase reaction product were found (P less than 0.001). In electron micrographs it could be seen that the tight junctions were intact and that there was a neuroendothelial transport, with horseradish peroxidase-filled vesicles, in the endothelium, muscle cells, and brain parenchyma. These vesicles represent a medium of transport for all proteins of high molecular weight and can therefore result in brain edema. It is concluded that nimodipine damages the blood-brain barrier by disturbance of the autoregulation of the cerebral blood flow.

Influence of type and extent of surgery on early results and survival time in glioblastoma multiforme.

We studied the influence of the type of surgery (microsurgery or macrosurgery) and extent (complete resection with lobectomy, complete resection alone, partial resection with lobectomy or partial resection alone) on early postoperative results and survival time in 118 consecutive patients who underwent surgery for glioblastoma multiforme. Early results were assessed by the Karnofsky score at 4 weeks postoperatively. Survival was compared using Kaplan-Meier curves and Mantel statistics. The median survival time (MST) after microsurgery (12.1 months) was significantly longer than that after macrosurgery (7.3 months). The longer survival after microsurgery was, however, largely attributable to better early results and a consequently higher proportion of patients who could undergo radiotherapy. Complete resection was superior to partial resection. Additional lobectomy did not appreciably influence the early results and the MST in completely resected tumours. So the MST after complete resection in the microsurgical group without lobectomy was 12.6 months, with lobectomy 12.9 months. In the macrosurgical group the respective values were 7.4 months without and 8.2 months with lobectomy. In incompletely resected tumours lobectomy worsened the early results compared to incomplete resection alone and led to a shorter MST.

[Prognostic value of grading systems in cerebral arteriovenous malformations]. / Zum prognostischen Wert von Graduierungssystemen bei zerebralen arteriovenösen Missbildungen.

The interrelationship between angiographic grading, clinical presentation and outcome in arteriovenous malformations was examined. For this purpose the grading scales as proposed by Luessenhop and Genarelli, Shi and Chen, and Spetzler and Martin were applied to 93 patients who had undergone surgery for cerebral arteriovenous malformations and whose angiographies were completely available for retrospective examination. Additionally the patients' clinical presentation on admission as well as their outcome were assigned to a 5 point scale. 44 of the 93 patients had a previous hemorrhage and 49 had become symptomatic for other reasons. There were 68 (73.2%) good and excellent results, 16 patients (17.2%) remained moderately and 7 (7.5%) severely disabled. There were 2 fatalities (2.1%). The correlation between the clinical and angiographical grading, respectively, and the outcome was assessed by determining Spearman's rank correlation coefficient (rho). The best correlation was found between the clinical grading on admission and the outcome (rho = 0.34). The angiographical classification scheme with the best correlation with the outcome was the one of Spetzler and Martin (rho = 0.22). The scales of Luessenhop and Genarelli and Shi and Chen correlated only weakly with the outcome (rho = 0.14 and rho = 0.12, respectively). The rounded off average of the grade of Spetzler and Martin and the clinical grade was the best predictor of outcome in our material (rho = 0.4).

[Spinal dysraphia and disordered ascension of the spinal cord in adults]. / Spinale Dysrhaphie und Ascensionsstörung des Rückenmarkes bei Erwachsenen.

Spinal dysraphism and tethered cord syndrome which frequently present with clinical symptoms during infancy, childhood and adolescence are rarely encountered in adults. In this retrospective study covering a period of 15 years were report of 12 patients aged from 22 to 71 years with delayed symptoms from the tethered spinal cord. The clinical signs and symptoms which consisted of progressing neurological, urological and orthopedic malfunctions as well as the aspects of current neuroradiological diagnosis including myelography, CT-scan and MRI are presented. The possible pathophysiological mechanism responsible for the delayed onset of the sequelae of the tethered cord are discussed. It is concluded that neurosurgical therapy should be performed in cases of progressing clinical deterioration and the results of surgery in our patient group are presented.