Discriminant Analysis of Intracranial Volumetric Variables in Patients with Normal Pressure Hydrocephalus and Brain Atrophy.

A method was developed for the computerized volumetric assessment of the intracranial cerebrospinal fluid (CSF) distribution. The study involved 62 patients differentiated into two groups: with CSF resorption disorders (normal pressure hydrocephalus - 30 patients) and without CSF resorption disorders (various types of brain atrophy - 32 patients). The goal of the study was to ascertain whether the assessment, depending on the linear discriminant analysis of volumetric brain features, could be an effective tool differentiating the two groups. Volumetric measurements were performed using VisNow software. For each patient, five features were determined and subjected to discriminant analysis: CSF volume in the subarachnoid space and basal cisterns (SV), CSF volume in the intracranial ventricular system (VV), brain volume (BV), total intracranial CSF volume (FV), and total intracranial volume (TV). Discriminant analysis enables the achievement of a high percentage of correct classification of patients to the appropriate group determined on the result of a lumbar infusion test. The discriminator, based on three features: BV, SV, and VV, showed a complete separation of the groups; irrespective of age. The squared Mahalanobis distance was 70.8. The results confirmed the applicability of the volumetric method. Discriminant analysis seems a useful tool leading to the acquisition of a computer-aided method for the differential diagnosis of CSF resorption disorders.

Polymerase chain reaction based detection of bacterial 16S rRNA gene in the cerebrospinal fluid in the diagnosis of bacterial central nervous system infection in the course of external cerebrospinal fluid drainage. Comparison with standard diagnostics currently used in clinical practice.

BACKGROUND AND PURPOSE: External drainage of cerebrospinal fluid (CSF) is a commonly used neurosurgical procedure. Complications of the procedure comprise central nervous system (CNS) bacterial infections, the frequency of which is estimated at around 6-10%. Detection of these infections is ineffective in many cases. The aim of the study was to evaluate the usefulness of a polymerase chain reaction (PCR)-based detection of bacterial 16S rRNA gene (16S rDNA) in the CSF. MATERIAL AND METHODS: The study group consisted of 50 patients. Clinical signs of CNS infection were monitored and routine laboratory and microbiological tests were performed. The results of standard methods were compared with the bacterial 16S rDNA detection. RESULTS: Using cultures, CNS infection was diagnosed in 8 patients, colonization of the drainage catheter in 6 patients, and sample contamination in 7 patients. In the group of the remaining 29 patients, no positive CSF culture was obtained and 13 of these patients also had all negative results for 16S rDNA detection. For the remaining 16 patients of this group, CNS infection, colonization of the catheter and sample contamination were diagnosed via PCR alone. Routine biochemical CSF tests and blood inflammatory parameters had a supporting value. CONCLUSIONS: Routine hospital tests do not provide rapid and efficient detection of the external drainage related bacterial CNS infection. It is justified to use several diagnostic methods simultaneously. The16S rDNA determination in CSF can increase the probability of detection of possible pathogens.

Comparison of eigeninference based on one- and two-point Green's functions.

We compare two methods of eigeninference from large sets of data. Our analysis points at the superiority of our eigeninference method based on one-point Green's functions and Padé approximants over a method based on fluctuations and two-point Green's functions. The first method is orders of magnitude faster than the second one; moreover, we found a source of potential instability of the second method and identified it as arising from the spurious zero and negative modes of the estimator for the variance operator of a certain multidimensional Gaussian distribution, inherent for that method. We also present eigeninference based on spectral moments of negative orders, for strictly positive spectra. Finally, we compare the cases of eigeninference of real-valued and complex-valued correlated Wishart distributions, reinforcing our conclusions on the advantage of the one-point Green's function method.

[The usefulness of the evaluation of volumetric and posturographic parameters in the differential diagnosis of hydrocephalus]. / Przydatnosc oceny parametrów posturograficznych i wolumetrycznych w diagnostyce róznicowej wodoglowia.

INTRODUCTION: A variety of diagnostic methods in normal pressure hydrocephalus and brain atrophy, it testifies to the difficulties in contrast to both teams. Develop a safe diagnostic tool having comparable statistical accuracy of the infusion test results would be of great clinical significance. The chances of implementing such a procedure in clinical practice, it may be a combination of these syndromes in the functional assessment (Posturography) the assessment of morphological CNS (volumetric). THE AIM: To evaluate and summary of the results of two non-invasive diagnostic methods morphological (posturography) and functional (volumetric) with results that were obtained from tests infusion. MATERIAL AND METHODS: The evaluation of volumetric and posturographic research was conducted in 39 patients including 27 patients with brain atrophy (BA) and in 12 patients with hydrocephalus (NPH). Volumetric measurements were made using proprietary software VisNow. Posturographic measurements performed using manual posturograph Pro-Med. RESULTS: Both the volume of CSF obtained by volumetric assessment, as well as the values of the analyzed parameters posturographic, highly correlate with the results of resistance resorption (R). The BA radius values sway with eyes open and closed R_OZ R_OO were consistent with test results infusion of 100% in the NPH radius values showed 75% compliance with the test results infusion. Volumetric parameters: the volume of CSF contained in the subarachnoid space and basal cisterns (SV) and the volume of CSF system intracranial ventricular (VV) were found in both patients NPH and BA 100% compatible resorption resistance (R). CONCLUSIONS: Simultaneous use of two non-standard methods of non-invasive (posturographic and volumetric) in the diagnostic process is a proposal to recognize normal pressure hydrocephalus and brain atrophy non-invasive methods, while maintaining very high statistical significance.

Analysis of intracranial volume ratios by means of cerebrospinal fluid deployment indicators.

INTRODUCTION: Imaging studies make it possible not only to visualize the general structure of the brain but also to take precise measurements of brain tissue volume and the size of individual lobes and their structure. The aim of this study was to determine the ratio of cerebrospinal fluid (CSF) volume contained in the intracranial ventricular system to the brain tissue volume and the ratio of CSF volume in the subarachnoid space and basal cisterns to the brain tissue volume. MATERIAL AND METHODS: The evaluation of volumetric measurements of computed tomographic (CT) images was undertaken on 23 male and female patients (average age 56.9 ± 6.1) diagnosed with normal pressure hydrocephalus (NPH) and 27 male and female patients (average age 70.6 ± 5.2) diagnosed with brain atrophy (BA). In the CT imaging studies, the total brain tissue volume and CSF volume collected in the intracranial fluid cavities were mapped to a colour scale. The VisNow software was used for volumetric evaluation. The groups were compared by means of the non-parametric Kolmogorov-Smirnov test (K-S) for independent samples. Paired data were compared by means of the nonparametric Wilcoxon test. RESULTS: The volumes of brain (brain volume - BV) and cerebrospinal fluid (fluid volume - FV) differ greatly from each other in both groups BA and NPH. The SBR (subarachnoid space and basal cisterns-to-brain ratio) and VBR (ventricle-to-brain ratio) indicators differ significantly and very much within the NPH group as well as within the BA group. In the NPH group a clearly higher value of VBR can be observed in comparison with the BA group. There was a higher value of SBR in the BA than the NPH group. CONCLUSIONS: The simultaneous use of two indicators, VBR and SBR, on a study group of 50 patients enabled the total separation of NPH and BA groups. This differentiation can have real diagnostic value. Thus the volumetric assessment of the volume of CSF and brain tissue based on CT of the head can become an important part of the differential diagnosis of hydrocephalus and brain atrophy.

Posturography in differential diagnosis of normal pressure hydrocephalus and brain atrophy.

Differentiation between normal pressure hydrocephalus (NPH) and brain atrophy is difficult in clinical practice. The purpose of this paper was to apply two advanced statistical, pattern recognition methods: discriminant analysis (DA) and k-nearest neighbour (K-NN) for the classification of NPH and atrophy patients to approach computer aided differential diagnosis. The classification is based on a few measures of the center of foot pressure (COP) movements (radius, area, and length). The posturography method gives a measure of current postural stability by a quantitative evaluation of postural sways. Measurements have been performed in the standing upright position in two conditions: with eyes open (EO) and closed (EC). The study comprises 18 patients (mean age 64 ±13 years) diagnosed as normal pressure hydrocephalus and qualifying for shunt implantation. The patients were evaluated by static posturography twice: before and after surgery. The NPH patients were compared with 36 atrophy patients (mean age 64±13 years) and 47 healthy persons (mean age 60 ±7 years). There were two basic dissimilarities in the NPH patients before surgery in comparison with the other groups: very large sways and their independence from vision. Over 90% of the NPH cases both before and after surgery were correctly classified. There also were over 90% of correctly classified patients if we compared the before surgery NPH and atrophy patients. Further posturographic measurements and data collection are needed to verify these results.

Posturography in differential diagnosis of patients with enlargement of brain ventricles.

BACKGROUND AND PURPOSE: This study aimed to quantitatively evaluate balance disturbances by means of static posturography in patients with enlargement of the ventricular system (Evans ratio > 0.3). MATERIAL AND METHODS: Fifty-four patients were diagnosed and treated in our Department of Neurosurgery. Thirty-six of them were qualified as patients with brain atrophy and 18 others were identified as patients with normal pressure hydrocephalus (NPH). Average sway radius and developed area of the posturogram were evaluated with eyes open and closed. These parameters constituted a base to calculate vision indices related to radius and area as a result of division of the difference of a given parameter (radius or area) measured with eyes closed and open by its corresponding sum. RESULTS: The sway range was significantly greater in patients with NPH in comparison to the control group. In NPH, there were no differences of sways observed with eyes open or closed - the vision indices were not statistically different from zero (vision index related to radius: -6.1 ± 18.9%, vision index related to area: -5.1 ± 34.7%). This may indicate no participation of sight in postural stability control. Values of the vision index related to radius (9.3 ± 19.4%) and to area (22.1 ± 28.2%) in the atrophy group significantly differed from zero, which indicated the participation of sight in postural stability control. CONCLUSIONS: Introduction of a new measure called the 'vision index' seems to be a promising clinical practice method of differentiation of hydrocephalus and brain atrophy.

Cerebrovascular reactivity evaluated by transcranial doppler sonography in patients after aneurysmal subarachnoid haemorrhage treated with microsurgical clipping or endovascular coiling technique.

OBJECTIVE: To examine cerebrovascular reactivity in patients after subarachnoid haemorrhage (SAH) during long-term follow-up, using Acetazolamide test and transcranial Doppler (TCD) monitoring of blood flow velocities (BFVs), to compare of CO(2) reactivity between patients after SAH treated with three different methods: surgical (clipping), endovasculary (coiling) and conservative. METHODS: The study was performed in a group of 24 patients treated for SAH. Cerebrovascular reactivity (CVR) has been evaluated after intravenous administration of 1000 mg of Acetazolamide. Studied patients were divided into three groups: group I (n = 10) treated with clipping, group II (n = 8) treated with coiling and group III (n = 6)--patients with negative angiography treated conservatively. RESULTS: Results of this study have shown that: (1) BFVs were normal in cerebral arteries and did not differ between right and left head sides, (2) CVR was normal in all studied patients, (3) method of aneurysm treatment as well as its localization had no influence on BFV and CVR, and (4) occurrence of vasospasm in early days after SAH did not result in permanent disturbances of CO(2) arterial reactivity. CONCLUSION: BFV values in cerebral arteries were in normal range and did not differ on the left and right head sides. CVR was normal in all examinated patients. A method of the ruptured aneurysm treatment and its localization had no influence on CBFV and CRV. Vasospasm in early period after SAH did not provoke a persistent impairment of CO(2) reactivity.

Ten years observation and treatment of multifocal pilocytic astrocytoma.

Pilocytic astrocytoma (PA) usually occurs in younger patients. It is a benign, generally well-delineated, WHO grade I tumour with favorable prognosis, which makes it different from diffuse astrocytomas, classified as higher grades of malignancy. A case study of PA was presented in a young female patient, observed and treated at the Neurosurgical Department for the period of 10 years, during which time she had frequent surgical procedures due to recurrence and dissemination of the tumour. The initial symptom of the disease was epileptic seizure at the age of 16. Neuroradiological study revealed cerebral tumour in the right temporal lobe, then the first temporal lobe surgery followed by re-operation and radiotherapy was performed. The patient developed hydrocephalus, treated with the ventriculo-peritoneal shunt. After 5 years local recurrence of the tumour appeared in the right temporal region. The patient was operated and the tumour was totally removed. Initially, the histopathological diagnosis of ganglioglioma was suggested for primary tumour, finally the diagnosis of pilocytic astrocytoma for both recurrent and primary tumour was established. During the next years of observation increasing neurological symptoms in lower limbs developed. Subsequently, the patient reported pain syndrome in lumbosacral and perineal area. Consecutive MRI studies revealed a spinal canal tumours localized at the thoracic level and next at sacral level. The spinal tumour was surgically treated in both locations; the last operation was done 10 years after surgery of the primary temporal lobe tumour. Histopathological examinations of the excised foci from spinal canal revealed neoplasm consistent with WHO grade I pilocytic astrocytoma. The presented case indicates that despite the spread of the neoplastic process, a histopathologically benign tumour (WHO I grade) allows for long-term survival and observation period. Unfortunately, multifocal tumour involving midline structures causes major neurological symptoms and deficits. In the presented case we dealt now with the ascending spread process and the occurrence of the new foci in both subtentorial and parameningeal spaces inside the cranial cavity. It is a rare clinical manifestation of a disease ever described in the literature.

[Posturography and computerized gait analysis in the Computer Dyno Graphy system as non-invasive methods for evaluation of normal pressure hydrocephalus progression]. / Badanie posturograficzne i komputerowa analiza chodu w systemie Computer Dyno Graphy jako nieinwazyjne metody oceny zaawansowania wodoglowia normotensyjnego.

Disturbances of gait and balance are important clinical problems in patients with normal pressure hydrocephalus. A considerable degree of locomotor disability and increased risk of falls are present in many cases. Accordingly, attempts to develop effective evaluation methods of gait and balance disturbances are made. Posturography and the Computer Dyno Graphy (CDG) system appear to be useful in diagnosis and evaluation of treatment in patients with normal pressure hydrocephalus. Both are non-invasive and repeatable methods that enable accurate evaluation of analyzed parameters at time intervals.

Gait disturbances in Computer Dyno Graphy examination in patients with normal pressure hydrocephalus before and after surgery.

BACKGROUND AND PURPOSE: Gait disturbances resulting from the normal pressure hydrocephalus (NPH) syndrome significantly restrain locomotion, which in serious cases can lead to a total loss of the ability to move. Hence the need to create an objective method of evaluating gait disturbances described by values of gait parameters and changes of these parameters resulting from neurosurgical treatment. The aim of this project is to create an effective, non-invasive diagnostics method describing movement disorders in patients with NPH before and after surgery. MATERIAL AND METHODS: An evaluation of the effectiveness of gait analysis was carried out with Ultraflex, which uses the Computer Dyno Graphy (CDG) system to measure the distribution of forces of reaction on the ground during walking. The control group consisted of 17 healthy individuals (age range 50-65 years) and the treatment group included 17 patients with enlargement of the ventricular system (9 females and 8 males, mean age 58.6 years, range 50-65 years), 8 of whom were qualified for surgical treatment. Analyzed parameters: ground reaction force, single and double support, stance. RESULTS: Changes of parameters reflected gait improvement. CONCLUSIONS: The results obtained indicate that gait analysis using the CDG system might be a good method for assessing the effectiveness of NPH surgery.

Free random Lévy and Wigner-Lévy matrices.

We compare eigenvalue densities of Wigner random matrices whose elements are independent identically distributed random numbers with a Lévy distribution and maximally random matrices with a rotationally invariant measure exhibiting a power law spectrum given by stable laws of free random variables. We compute the eigenvalue density of Wigner-Lévy matrices using (and correcting) the method by Bouchaud and Cizeau, and of free random Lévy (FRL) rotationally invariant matrices by adapting results of free probability calculus. We compare the two types of eigenvalue spectra. Both ensembles are spectrally stable with respect to the matrix addition. The discussed ensemble of FRL matrices is maximally random in the sense that it maximizes Shannon's entropy. We find a perfect agreement between the numerically sampled spectra and the analytical results already for matrices of dimension N=100 . The numerical spectra show very weak dependence on the matrix size N as can be noticed by comparing spectra for N=400 . After a pertinent rescaling, spectra of Wigner-Lévy matrices and of symmetric FRL matrices have the same tail behavior. As we discuss towards the end of the paper the correlations of large eigenvalues in the two ensembles are, however, different. We illustrate the relation between the two types of stability and show that the addition of many randomly rotated Wigner-Lévy matrices leads by a matrix central limit theorem to FRL spectra, providing an explicit realization of the maximal randomness principle.

Growth hormone cell phagocytosis in adenohypophysis of mosaic mice: morphological and immunocytochemical electron microscopy study.

An electron microscopy immunocytochemical study was performed to determine the expression pattern of growth hormone (GH) in mosaic mutant mice adenohypophysis. In normal condition GH was restricted to the secretory granules of all growth hormone cells. Mosaic mice adenohypophysis contained growth hormone cells which have distinctive GH labeled secretory granules at the level seen in control animals. Ultrastructurally, some GH cells of mosaic mice presented abnormalities, but labeling intensity of secretory granules in these cells was always comparable to the basal condition. The striking findings presence of two forms (simple and activated) of folliculo-stellate cells (FS) in close association trough gap or tight junction with GH cells localized especially near the perivascular space. Frequently, in cytoplasm of FS cells, large clusters containing fragments of GH labeled cell were present. Additionally, the existence of large intracellular, electron-lucent spaces, with remnant cellular material in parenchyma of mosaic mutant mice adenohypophysis could suggest intensive process of GH-cell destruction. Our electron microscopy immunocytochemical results provide evidence for loss of GH cells in mosaic mice by phagocytosis. We suppose that impaired body growth observed in mosaic mutant male rats may be, at least partially, a consequence of an alteration in somatotropic axis activity. Loss of GH cells in mosaic mice by phagocytosis supported by FS cells may contribute to this effect.

[Diagnostic difficulties due to atypical symptoms in normal pressure hydrocephalus. A case report]. / Problemy diagnostyczne nietypowych objawów w wodoglowiu normotensyjnym. Opis przypadku.

This paper presents a case of a female patient with unusual symptoms of diagnosed hydrocephalus. Symptoms demonstrated by the patient were initially diagnosed as immature personality, after that she was diagnosed with reactive depressive disorders. For those reasons she was treated for over 20 years in different psychiatric outpatient clinics and psychiatric hospitals. She was treated pharmacologically with different medications: antidepressants, neuroleptics etc. She also participated periodically in individual and group psychotherapy. Computed tomography performed after the loss of consciousness with significant motor deficits revealed relevant dilation of the cerebral ventricular system. The neuropsychological examination revealed disturbances in emotional-motivation area and cognitive deficits. Those disorders caused significant problems in social and professional activities. After completing the diagnosing process the patient was diagnosed with arrested hydrocephalus. Results of clinical examinations suggested that at this stage of the disease there are no indications for shunt implantation. Probably earlier diagnosis could bring a chance of successful neurosurgical intervention and definitely more efficient therapy.

Spectral moments of correlated Wishart matrices.

We present an analytic method to determine the spectral properties of the covariance matrices constructed of correlated Wishart random matrices. The method gives, in the limit of large matrices, exact analytic relations between the spectral moments and the eigenvalue densities of the covariance matrices and their estimators. The results can be used in practice to extract the information about genuine correlations from the given experimental realization of random matrices.

Cerebrospinal fluid free-radical peroxidation products and cognitive functioning patterns differentiate varieties of normal pressure hydrocephalus.

The aims of the study were as follows: first, to verify the hypothesis that free radical peroxidation may be one of the factors implicated in pathophysiology of normal pressure hydrocephalus (NPH) and, second, to find out whether these biochemical characteristics together with neuropsychological cognitive deficits can differentiate between various types of NPH. This provides prognostic criteria for selection of patients for shunt surgery. Lipid peroxidation was measured in terms of thiobarbituric acid-reactive material (TBAR) and protein sulphydryl (SH) groups were measured as CSF content. Cognitive deficits were assessed using a number of neuropsychological tests. In the sample of NPH patients (n = 24), three categories were distinguished using these criteria: idiopathic active hydrocephalus (A), arrested hydrocephalus (AH), and post-traumatic hydrocephalus (PT). TBAR levels for NPH patients were higher than that of controls without CNS pathology (n = 2). Moreover, NPH patients had increased levels of total and soluble protein groups, and decreased levels of protein SH groups, which suggests the occurrence of processes that activate peroxidation of free radicals in normal pressure hydrocephalus. Levels of these indicators varied across NPH types. Two categories of NPH patients, with active (A) or posttraumatic (PT) hydrocephalus differed significantly from the controls (C)--their TBAR levels were 0.58, 0.56 and 0.28 nmol/mg protein, respectively; soluble SH levels: 41.5; 58.15 and 11.3 nmol/mg protein, and protein SH levels: 34.3, 21.8 and 57.5 nmol/mg protein. In PT group, many individual differences were noticed. These findings seem promising because the studied biochemical indicators may serve as additional diagnostic criteria for selection of NPH patients for shunting.

Free random Lévy matrices.

Using the theory of free random variables and the Coulomb gas analogy, we construct stable random matrix ensembles that are random matrix generalizations of the classical one-dimensional stable Lévy distributions. We show that the resolvents for the corresponding matrices obey transcendental equations in the large size limit. We solve these equations in a number of cases, and show that the eigenvalue distributions exhibit Lévy tails. For the analytically known Lévy measures we explicitly construct the density of states using the method of orthogonal polynomials. We show that the Lévy tail distributions are characterized by a different novel form of microscopic universality.

Application of dynamic CT scan and CT densitometry in the evaluation of brain volume enlargement

Foram utilizados gatos, submetidos a lesao cerebral por hipotermia, compressao epidural por balao seguida de subita descompressao, como modelos de edema vasogenico ou isquemico e vasoplegia dos vasos cerebrais. A tomografia computadorizada dinamica e a tomografia computadorizada densitometrica foram usadas para o diagnostico diferencial entre edema cerebral e modificaçoes decorrentes da vasoplegia. Os metodos tomograficos utilizados mostraram-se muito uteis para a avaliaçao diagnostica. A correlaçao entre a tomografia computadorizada dinamica e a tomografia computadorizada densitometrica tornou possivel avaliar os disturbios da auto-regulaçao da circulaçao cerebral permitindo concluir que estes metodos poderao ser empregados em investigaçao clinica