Evans Ratio Research Articles

One-dimensional-ratio measures of atrophy progression in multiple sclerosis as evaluated by longitudinal magnetic resonance imaging

For decades, normalized one-dimensional (1D) measures have been used in the evaluation of brain atrophy. In multiple sclerosis (MS), the use of normalized linear measures over longitudinal follow-up remains insufficiently documented. To evaluate the association between different regional atrophy measures and disability in MS patients over four decades in a longitudinal cross-sectional study. 37 consecutively selected MS patients were included. At baseline, patients had a range of disease duration (1-33 years) and age (24-65 years). Each patient was followed by magnetic resonance imaging (MRI) for a mean of 9.25 years (range 7.3-10 years). Four 1D measures were applied at three time points on axial 5-mm T1-weighted images. Three clinical MS subgroups were represented: relapsing-remitting MS (RRMS), secondary progressive MS (SPMS), and primary progressive MS (PPMS). There were significant changes in all 1D ratios during follow-up. The Evans ratio (ER) and the bifrontal ratio (BFR) were associated with the development of disability. Changes of ER and BFR reflected more aggressive disease progression, as expressed by MS severity score (MSSS). All four normalized ratios showed uniform atrophy progression, suggesting a consistent rate of atrophy over long-term disease duration independent of MS course. Disability status correlated with 1D measures, suggesting that serial evaluation of Evans and bifrontal ratios might contribute to the radiological evaluation of MS patients.

Comparison of Computed Tomography 3-Dimensional Volumetric Analysis of Ventricular Size to Visual Radiological Assessment

Interpretation of ventricular volume on computed tomography scans of hydrocephalus patients is usually subjective. The objective of this study was to determine whether radiological assessment of interval change correlates better with an objective calculated volume change or with other objective 2-dimensional estimates of ventricle volume change. Ventricular volume, Evans ratio, and frontal and occipital Horn ratio were retrospectively assessed on 95 pairs of scans from patients with a ventriculoperitoneal shunt. To determine ventricle volume, all voxels of cerebrospinal fluid density were isolated on a 3-dimensional reconstructed computed tomography scan. Voxels of fluid density contiguous with one another in the ventricular system were isolated. Radiological assessments of interval change were divided into 5 groups based on reported findings in the radiology report. The 95% mean confidence intervals were developed for changes in the measured parameters, given a particular radiological assessment. Multinomial regression was subsequently performed to determine which parameter was most closely correlated with the radiological assessment. Significant overlap was found in the confidence intervals for objectively calculated volume change between the different categories of radiological assessment. The frontal and occipital Horn ratio had the most consistent correlation with the radiological assessment, followed by the Evans ratio. Objectively calculated volume change correlated poorly with radiological assessment. Radiological interpretation does not correlate well with objectively calculated volume changes, but correlates better with other parameters that approximate volume and are likely used to visually evaluate interval change. We recommend that ventricle volume be objectively measured to increase consistency between radiological interpretation and actual interval changes.

Influence of obstetric complication severity on brain morphology in schizophrenia: an MR study

The purpose of this study was to determine if a causal relationship exists between obstetric complications (OCs) severity and linear magnetic resonance (MR) measurements of brain atrophy in patients with schizophrenia. Linear measurements of ventricular enlargement (bifrontal span, Evans ratio, and bicaudate ratio) and hippocampal atrophy (interuncal distance) were completed on MR images obtained in 47 patients with schizophrenia. Regression analysis was used to look at association with OCs severity, assessed by the "Midwife protocol" of Parnas and colleagues. The relationship between MR measurements and phenomenologic variables such as age at onset, illness duration, and exposure to antipsychotic medications was explored. The relationship between MR measurements, OCs severity, and symptom presentation was also investigated. OCs severity was significantly associated with MR measurements of ventricular enlargement (bifrontal span, Evans ratio). As the severity of OCs increased, bifrontal span and Evans ratio increased. This effect was independent of age at onset, illness duration, or even antipsychotic treatment. Interestingly, bifrontal span, Evans ratio, and OCs severity score all showed a significant positive correlation with hallucinatory symptomatology. Although confirmatory studies are needed, our findings would support the idea that environmental factors, in this case severe OCs, might partly contribute to ventricular abnormalities in schizophrenia.

Intracranial (structural) changes in obsessive- compulsive disorder: A computerized tomography scan study

Objective:To assess intracranial structural changes in obsessive-compulsive disorder (OCD) with CT scan.Materials and Methods:Thirty patients of OCD between 21 and 40 years of age and fulfilling various inclusion and exclusion criteria were compared with control group. CT scans of all the patients and controls were taken and compared with regard to ventricular size, Evan’s ratio and ventricular brain ratio (VBR).Results:Patients of OCD were found to have greater cortical atrophy and scored significantly higher in frontal and parietal area. Only 4 patients had enlarged ventricles, and there were none with a smaller ventricle. Mean Evan’s ratio of patients was lower than that of the control group but the difference was statistically nonsignificant. The mean VBR of patients was lower than that of the control group and the difference was highly significant.Conclusions:The evidence of neuro-radiological abnormalities in patients with OCD suggests that these disorders should not be considered merely functional in the traditional sense.

Communicating hydrocephalus in adult rats with kaolin obstruction of the basal cisterns or the cortical subarachnoid space

Communicating hydrocephalus (CH) occurs frequently, but clinically-relevant animal models amenable to diagnostic imaging and cerebrospinal fluid shunting are not available. In order to develop and characterize models of subarachnoid space (SAS) obstruction at the basal cisterns (BC) or cerebral convexities (CX), 25% kaolin was injected in adult female Sprague–Dawley rats following halothane anesthesia; intact- or saline-injected animals served as controls. For BC animals ( n = 28 hydrocephalics, n = 20 controls), an anterior approach to the C1-clivus interval was employed and 30 μl of kaolin or saline was injected. For CX injections ( n = 13 hydrocephalics, n = 3 controls), 50–60 μl of kaolin was injected bilaterally after separating the partitions in the SAS. In BC-injected rats, kaolin was observed grossly in the basal cisterns but not in the cisterna magna or at the foramina of Luschka, indicating that communicating (or extra-ventricular) – not obstructive – hydrocephalus had been induced. Following ketamine/xylazine anesthesia, magnetic resonance imaging (MRI) of gadolinium injected into the lateral ventricle also demonstrated CSF flow from the foramina of Luschka. MRI also revealed that ventriculomegaly progressed steadily in BC animals and by 2 weeks post-kaolin the mean Evan's ratio (frontal horn) increased significantly (mean 0.45 compared to 0.31 in intact- and 0.34 in saline-injected controls; p < 0.001 for each). CX animals exhibited kaolin deposits covering approximately 80% of the cerebral hemispheres and developed noticeable ventriculomegaly (mean Evan's ratio 0.40), which was significant relative to intact animals ( p = 0.011) but not saline-injected controls. Surprisingly, ventriculomegaly following CX injections was less severe and much more protracted, requiring 3–4 months to develop compared to ventriculomegaly produced by BC obstruction. No hydrocephalic animals demonstrated obvious neurological deficits, but BC-injected animals that subsequently developed more severe ventriculomegaly exhibited nasal discharges and “coughing” for several days following kaolin injection. The new BC model is relevant because the clinical presentation of CH in children is often associated with obstruction at this site, while the CX model may be more representative of late adult onset normal pressure hydrocephalus.

Lymphatic cerebrospinal fluid absorption is impaired in a kaolin-induced hydrocephalus model in the rat

Materials and methods Kaolin (n = 10) or saline as control (n = 9) was introduced into the basal cisterns of Sprague Dawley rats and the development of hydrocephalus was assessed using MRI. The degree of ventriculomegaly was calculated for each animal as the Evans ratio. Human serum albumin (125IHSA) was injected into the lateral ventricles. The enrichment of 125I-HSA in the olfactory turbinates at 30 minutes post injection provided an estimate of CSF transport through the cribriform plate into the nasal lymphatic vessels.

Neurological soft signs and cerebral measurements investigated by means of MRI in schizophrenic patients

Neurophysiologic research has shown a Neurological Soft Sign (NSS) characteristic prevalence in schizophrenic patients, and correlations between NSS and the most frequently cerebral alterations. The aim of this study was to investigate, by means of MRI, the quantitative alterations of cortical and subcortical structures and their correlation with NSS in a sample of schizophrenic patients. Linear measures of lateral ventricular (Evans ratio), third ventricular (Third Ventricular Width), hippocampal (Interuncal Index) and cerebellar (Verm Cerebellar Atrophy) atrophy were made on magnified MR images of 33 patients with a DSM IV diagnoses of chronic schizophrenia. NSS were evaluated with the Buchanan and Heinrichs's Neurological Evaluation Scale (NES). Lateral ventricular enlargement showed to be correlated with right stereoagnosia item ( p = 0.001). Hippocampal atrophy, with right stereoagnosia item ( p = 0.023), with forefinger-right thumb opposition ( p = 0.004), forefinger-left thumb opposition ( p = 0.029 and face-hand extinction (0.26). Third ventricle enlargement showed to be correlated with forefinger-right thumb opposition ( p = 0.001), forefinger-left thumb opposition( p = 0.021) and total sensorial integration ( p = 0.012). Cerebellar atrophy showed to be correlated with rhythmic drumming item ( p = 0.042), forefinger-right thumb opposition ( p = 0.007), forefinger-left thumb opposition ( p = 0.026), left specular movements ( p = 0.049), face-hand extinction ( p = 0.001), right-left confusion ( p = 0.005) and with left forefinger-nose index ( p = 0.032). Results obtained confirm the correlation between NSS and neuroanatomical alterations in schizophrenia.

Development of Chronic Hydrocephalus and Early Cranial CT Findings in Spontaneous Intracerebral/Intraventricular Hemorrhage

Since intracerebral hemorrhage (ICH) is frequently associated with intraventricular bleeding (IVH), we sought to detect cranial computed tomography features that would indicate early on in the patient's history the development of chronic hydrocephalus with a permanent need for cerebrospinal fluid (CSF) diversion. A total of 25 consecutive cases presenting with ICH/IVH was studied retrospectively. Outcome was assessed using the Glasgow Outcome Scale at an average of 8 months subsequently. Diagnosis of ICH/IVH and (acute) hydrocephalus was made by early cranial CT scanning employing a selection of radiological criteria according to the literature including the Evans ratio. All patients then received external ventricular drainage. Chronic hydrocephalus was diagnosed by intraventricular pressure monitoring or by cranial CT follow-up after removal of the external drainage. None of the radiological criteria nor the scores obtained differed between the two groups. However, the ratio of scores for IVH/ICH was higher among the patients who developed a chronic hydrocephalus. All other parameters including volume of ICH and IVH were equally distributed. Overall outcome was poor with a median GOS score of 3. The ICH/IVH ratio presented here can be interpreted as an individual measure of propensity to impairment of CSF circulation. Further studies on larger populations will be needed to show whether this can be employed as an early diagnostic criterion with respect to chronic hydrocephalus.

Ventriculostomia endoscópica: influencia de factores predisponentes al fallo y evolución del tamaño ventricular

Endoscopic third ventriculostomy is the treatment of choice for non communicating hydrocephalus at our institution. Several factors have been associated with failure of endoscopic third ventriculostomy. The goals of the study have been to evaluate the outcome, the influence of factors theoretically prone to failure of ventriculostomy and the evolution of ventricular size. Fifty-six patients (mean age 48.5 yrs) treated with an endoscopic third ventriculostomy during the period 1997-2002 were analysed retrospectively. Hydrocephalus was classified as acute (68%) and chronic forms. Etiology was classified in space-occupying lesions (59%), primary aqueductal stenosis (34%) and Chiari malformation (7%). The presence of the following factors theoretically prone to failure was considered: age below one year, history of mielomeningocele, cerebrospinal fluid (CSF) infection, intracranial haemorrhage, radiotherapy, craniotomy and previous treatment of hydrocephalus with a shunt. Ventricular size was measured linearly with four ventricular index pre- and postoperatively. The global success rate was 71.4% (mean follow-up 26 months). Endoscopic third ventriculostomy for hydrocephalus secondary to cerebral metastases obstructing CSF pathways was associated with a higher risk of failure (p=0.006). None of the risk factors considered was associated with a higher risk of failure. The evolution of the ventricular size measured with linear methods is associated with outcome. Evans ratio, third ventricle index, cella media index and ventricular score decreased in patients whose outcome is satisfactory and increased in those cases deemed clinical failures (p< 0.05). The risk of failure increases in patients with cerebral metastases close to CSF pathways, likely due to the concurrence of mechanisms other than obstruction. Changes in ventricular size are associated with outcome.

Frontal and Occipital Horn Width Ratio for the Evaluation of Small and Asymmetrical Ventricles

The aim of this study was the introduction of a new linear ventricular measurement which has a better correlation with ventricular volume than the commonly used linear measurements, especially in chronically shunted patients with small and/or asymmetrical ventricles. Ventricular volume, brain volume, Evans ratio, Schierman index, cella media index and frontal and occipital horn ratio were measured from CT scans of 57 shunted hydrocephalic patients and 20 normal control children. Four groups of patients were identified with regards to the ventricular size and symmetry (small, large, symmetrical and asymmetrical). A new linear measurement was defined as half of the ratio of the frontal and occipital ventricular width to that of the skull (frontal and occipital horn width ratio; FOHWR) and compared to other linear measurements in different patient groups. FOHWR showed better correlation with ventricular size and ventricular brain ratio than the ventricular linear measurements currently in use, especially in chronically shunted patients with small and/or asymmetrical ventricles.

Increased intracranial pressure in myelomeningocele (MMC) patients never shunted: results of a prospective preliminary study.

In some young adults non-shunted myelomeningocele (MMC) patients without symptoms or with unspecific clinical findings, moderate or severe stabilised ventriculomegaly are observed in control CT scans. Physicians are then faced with the so-called 'Arrested Hydrocephalus' (AH) syndrome. The present study is part of a prospective protocol in which patients with hydrocephalus associated with MMC and long-term clinical diagnosis of AH were included. To evaluate myelomeningocele patients never shunted with clinical and/or CT scan criteria compatible with AH. Multidisciplinary Spina Bifida Unit in a tertiary university hospital in Barcelona, Spain. Fourteen MMC patients were selected, in all of them, continuous intracranial pressure (ICP) monitoring was performed. Analysis of the ICP records was done using the method described by Borgesen in mmHg. All patients were also studied by intelligence quotient (IQ) testing before and after shunting. The CT in all the study cases showed an Evans ratio </=0.30. The majority of patients (11/14) presented continuous high or intermittently raised ICP (active or unstable compensated hydrocephalus group) and in three (3/14) cases we confirmed the diagnosis of arrested hydrocephalus. There were no complications associated with ICP monitoring. In view of our results, we believe that in all non-shunted cases with clinical and/or CT scan criteria compatible with AH, the use of an objective method, such as continuous ICP monitoring, is necessary to diagnose arrested hydrocephalus, and a more comprehensive method that includes extensive neuropsychological valoration should be developed for the diagnosis and treatment of arrested hydrocephalus. Supported in part by Grant number 97-0923 from the Fondo de Investigaciones Sanitarias de la Seguridad Social (FISS).

Linear CT-scan measurements in alcohol-dependent patients with and without delirium tremens

The aims of the present study were to examine whether chronic alcohol dependence and the development of delirium tremens are characterized by changes in linear CT measurements of brain liquor spaces and intracranial distances indicative of prefrontal atrophy, and frontal (sub)cortical or temporal (sub)cortical atrophy. Toward this end linear measurements were performed in 47 alcohol dependent patients with and without a history of delirium tremens and in 10 healthy volunteers using CT-scanning. The following linear measurements were calculated: (1) the Evans ratio; (2) the cella media index (CMI); (3) the maximum width of the third ventricle; (4) the maximum width of the fourth ventricle; (5) the maximum frontal subarachnoid space (MFSS); (6) the maximum width of the anterior interhemispheric fissure (MIF), and (7) the maximum width of the Sylvian fissure (MSF). The alcoholics were divided into subgroups according to the Münchner Alkoholismus Test (MALT) and the presence of delirium tremens. The MFSS of the alcohol-dependent patients was significantly larger than that of the controls. The MIF and MSF of high MALT scorers were significantly larger than those of low scorers and controls. Alcohol-dependent patients with a known history of delirium tremens had significantly larger MIF and MSF than did patients without delirium tremens and controls. The results suggest that alcohol dependence is characterized by prefrontal atrophy, and that frontal cortical and temporal (sub)cortical atrophy may be related to the development of delirium tremens.

Relationship between brain atrophy estimated by a longitudinal computed tomography study and blood pressure control in patients with essential hypertension.

To evaluate the relationship between blood pressure control and the progression of brain atrophy in the elderly, patients with essential hypertension and brain atrophy were longitudinally evaluated using computerized tomography (CT). The study evaluated 48 patients with essential hypertension aged 46-78 years, and 30 sex- and age-matched normotensive control subjects. The extent of brain atrophy as determined by caudate head index (CHI), the inverse cella media index (iCMI), and Evans' ratio (ER) was estimated twice at an interval of 5-9 years (mean, 6.9 years). The mean annual increases in CHI (deltaCHI), iCMI (delta iCMI), and ER (deltaER) were evaluated. Mean blood volume in the common carotid artery (BF) and the decrease in BF per year (deltaBF) were also determined. The deltaCHI, delta iCMI, and deltaER increased with age in the hypertensive subjects as well as the control group across all age groups evaluated. The deltaCHI, delta iCMI, and deltaER were significantly greater in the patients with essential hypertension in their 50 s as compared with the controls. In patients with essential hypertension aged 65 years or older, the deltaCHI, delta iCMI, and deltaER were significantly lower in the group in whom the blood pressure was controlled within the range of borderline hypertension than the groups in which it was controlled in the range of normal or mild hypertension. In the younger patients under the age of 65 with essential hypertension, blood pressure control did not affect the deltaCHI, delta iCMI, and deltaER. The deltaCHI, delta iCMI, and deltaER were significantly correlated with deltaBF in both groups. These findings indicate that control of systolic blood pressure within the range of borderline hypertension may delay the progression of brain atrophy in elderly patients with essential hypertension.

West syndrome with periventricular leukomalacia: a morphometric MRI study

A morphometric magnetic resonance imaging study was performed, and the results were compared among three groups (group 1, periventricular leukomalacia patients with West syndrome; group 2, periventricular leukomalacia patients without West syndrome; and group 3, control patients) to clarify the characteristics and cause of West syndrome. This study included 21 infants (11 males and 10 females, 7 months to 2 years 8 months old) born at 24-32 weeks of gestation and weighing 625-1,908 gm. The Evans ratio, ratio of the posterior horns, Cella media index, width of the third ventricle, and the areas of the midbrain, pons, and medulla oblongata were measured and compared among the three groups. There were no differences of gestation or birth weight among the three groups. The Evans ratio, ratio of the posterior horns, Cella media index, and width of the third ventricle were larger in group 1 than in groups 2 and 3. The ratio of the posterior horns and Cella media index were larger in group 2 than in group 3, although the width of the third ventricle was not. Myelination was delayed in all patients in group 1 and in two patients in group 2. In group 1 the areas of the midbrain and pons were smaller than in groups 2 and 3 and the medulla oblongata was smaller than in group 3, although there were no differences in midbrain, pons, and medulla oblongata between groups 2 and 3. Although the infants with periventricular leukomalacia and West syndrome frequently demonstrated marked ventricular dilatation and delayed myelination, the atrophy of midbrain and pons was the most characteristic, and the damage may cause West syndrome.

Vascular dementia of Binswanger's type: clinical, neuroradiological and 99mTc-HMPAO SPET study.

In 24 patients with vascular dementia of Binswanger's type (VDBT) and 14 age-matched neurologically normal volunteers, we investigated the relationship between clinical features, white matter lesions (leuco-araiosis) and cerebral atrophy on computed tomographic (CT) scan, and regional cerebral blood flow. All subjects underwent the Mini-Mental State Examination of Taiwan, version 1 (MMSE-T1), for assessing the severity of cognitive impairment. The patients were subdivided into two groups, one with mild to moderate (group I, MMSE-T1 scores: 11-24, n=11), and the other with severe dementia (group II, MMSE-T1 scores: below 10, n=13). White matter degeneration was evaluated with densitometric methods. Loss of brain parenchyma was estimated with seven linear measurements (Evan's ratio, third ventricle ratio, width of temporal horn tip, anterior-posterior length of temporal horn, anterior-posterior length of Sylvian fissure and width of frontal interhemispheric fissure) by CT scans. Regional cerebral blood flow was determined with technetium-99m hexamethylpropylene amine oxime (HMPAO) single-photon emission tomography (SPET). In neuroimaging studies, subcortical leuco-araiosis was localized at the frontal region in group I patients and scattered diffusely in group II patients. 99mTc-HMPAO SPET analysis revealed reduction of regional cerebral blood flow in the frontal lobe in group I patients and widespread reduction of regional cerebral blood flow in group II patients. A correlation between frontal leuco-araiosis and perfusion defect of the frontal pole was demonstrated in group I patients, showing findings typical of subcortical dementia. There was no difference in frontal atrophic measurements between group I patients and controls. Ratios of volumes of lost brain parenchyma and leuco-araiosis were significantly higher in group II patients than in the age-matched controls, corresponding to a diffuse cerebral perfusion defect. These results suggest that patients with VDBT have early frontal lobe involvement with posterior progression. Patients with mild VDBT are more likely to show reduction of frontal cerebral blood flow and leuco-araiosis, while those with severe VDBT are more likely to have diffuse leuco-araiosis, cerebral hypoperfusion and brain atrophy.

Progression of Cerebral Atrophy in Patients on Regular Hemodialysis Treatment: Long-Term Follow-Up with Cerebral Computed Tomography

Fifteen patients (10 males, 5 females) on regular hemodialysis treatment (average age 43.6 +/- 4.0 years, average time on dialysis 100.7 +/- 62.8 months) underwent cerebral computed tomography between 1981 and 1984. Ten patients showed mild cerebral atrophy (CA) on the basis of cortical sulci exceeding 3 mm in breadth and an Evans ratio exceeding 0.31, for a total of 14 degrees of CA (mean 0.9 +/- 1). The same 15 patients underwent a second cerebral computed tomography during 1991/92 (101 +/- 23.7 months later). At that time, the patients exhibited a degree of CA of 2.6 +/- 1.4, for a total of 39 degrees with an overall increase of 25 degrees. Since CA is not detected before the age of 55 years in the normal population, we conclude that the CA in this patient group can only be attributed to uremia-related pathology and that it tends to worsen as regular hemodialysis treatment continues. Nevertheless, no evident cognitive, affective, or behavioural changes were verified in these patients. To our knowledge, this is the first presentation of radiologically documented progression of CA in the same patient population over time.

Phosphorus-31 magnetic resonance spectroscopy and ventricular enlargement in bipolar disorder

Phosphorus-31 magnetic resonance spectroscopy ( 31P-MRS) was used to examine whether reduced levels of phosphomonoesters (PME) were correlated with ventricular enlargement in 40 patients with bipolar disorder and 60 agematched normal control subjects. Ventricular enlargement was assessed by magnetic resonance imaging ( 1H-MRI) using the following three methods: Evans ratio (ER), Huckman number (HN), and minimum distance of caudate nuclei (MDCN). Although MDCN and ER were significantly larger in the patient group, no significant correlations were found between 31P-MRS and 1H-MRI. PME was negatively correlated with age in bipolar disorder. Decreased levels of PME were found only in bipolar I disorder. Intracellular pH was positively correlated with duration of lithium treatment. These results suggest that the observed PME reduction was not related to ventricular enlargement, but the issue should be further studied with volumetric MRI analysis.

Analysis of computed X-ray tomography of the brain in incontinence patients with senile dementia. Relationship between circulatory defect of the brain, brain atrophy and urinary incontinence

To evaluate the condition of incontinence in patients with senile dementia, we performed computed tomography X-rays to the brain and analyzed the relationship among the circulatory defect of the brain, the brain atrophy and the degree of incontinence. There were 92 patients subjected to this study who were hospitalised due to senile dementia; 74 patients had vascular dementia, 10 patients had senile dementia of Alzheimer type, and 8 patients had the mixed type. (age ranged: 54-95 years; mean: 80.3 years). The degree of incontinence in these patients varied as follows: 18 patients with continence, 16 patients with moderate incontinence, 58 patients with total incontinence. The diagnosis of circulatory defect of the brain was based on computed tomography observation of periventricular lucency (P.V.L.), and the degree of brain atrophy was evaluated based on 4 criteria: the Lateral body ratio, the Huckman number, the Evans ratio, and the enlargement of the subarachnoid space. Among the 92 patients, P.V.L. was present in 31 patients, among them 27 patients suffered from incontinence. There was a significant correlation between P.V.L. and incontinence (p < 0.001). As the incontinence progressively worsened (Continence, Moderate incontinence Total incontinence), the lateral body ratio increased to 24.8, 27.8, 28.6, (p < 0.05). The Huckman number also increased to 18.3, 19.3, 21.3, (p < 0.01), and the evans ratio likewise 29.9, 32.3, 33.7 (p < 0.01). The enlargement of the subarachnoid space was also correlated with the severity of incontinence. We conclude that urinary incontinence originating from senile dementia is connected to brain atrophy and is strongly influenced by the circulatory disorders of the brain.

99mTc-d,l-HMPAO and SPECT of the Brain in Normal Aging

Single photon emission computed tomography (SPECT) with 99mTc-d,l-hexamethylpropyleneamine oxime (99mTc-d,l-HMPAO) was used to determine global and regional CBF in 53 healthy subjects aged 21-83 years. For the whole group, global CBF normalized to the cerebellum was 86.4% +/- 8.4 (SD). The contribution of age, sex, and atrophy to variations in global CBF was studied using stepwise multiple regression analysis. There was a significant negative correlation of global CBF with subjective ratings of cortical atrophy, but not with ratings of ventricular size, Evans ratio, sex, or age. In a subgroup of 33 subjects, in whom volumetric measurements of atrophy were performed, cortical atrophy was the only significant determinant for global CBF, accounting for 27% of its variance. Mean global CBF as measured with the 133Xe inhalation technique and SPECT was 54 +/- 9 ml/100 g/min and did not correlate significantly with age. There was a preferential decline of CBF in the frontal cortex with advancing age. The side-to-side asymmetry of several regions of interest increased with age. A method was described for estimation of subcortical CBF, which decreased with advancing cortical atrophy. The relative area of the subcortical low-flow region increased with age. These results are useful in distinguishing the effects of age and simple atrophy from disease effects, when the 99mTc-d,l-HMPAO method is used.

Reappraisal of the intracranial pressure and cerebrospinal fluid dynamics in patients with the so-called ?Normal pressure hydrocephalus? syndrome

Fifty-four shunt-responsive patients were selected from a prospective protocol directed to study patients with suspected normal pressure hydrocephalus (NPH). Patients with gait disturbances, dementia, non-responsive L-Dopa Parkinsonism, urinary or faecal incontinence and an Evans ratio greater or equal to 0.30 on the CT scan were included in the study. As a part of their work-up all patients underwent intracranial pressure monitoring and hydrodynamic studies using Marmarou's bolus test. According to mean intracranial pressure (ICP) and the percentage of high amplitude B-waves, patients were subdivided in the following categories: 1) Active hydrocephalus (mean ICP above 15 mmHg), which is in fact no tone normal pressure hydrocephalus; 2) Compensated unstable hydrocephalus, when mean ICP was below 15 mmHg and B-waves were present in more than 25% of the total recording time and 3) Compensated stable hydrocephalus when ICP was lower or equal to 15 mmHg and beta waves were present in less than 25% of the total recording time. The majority of the patients in this study (70%) presented continuous high or intermittently raised ICP (active or unstable compensated hydrocephalus group). Mean resistance to outflow of CSF (Rout) was 38.8 mm Hg/ml/min in active hydrocephalus and 23.5 mm Hg/ml/min in the compensated group (Students t-test, p less than 0.05). Higher resistance to outflow was found in patients with obliterated cortical sulci and obliterated Sylvian cisterns in the CT scan. No statistically significant correlation was found when plotting the percentage of beta waves against pressure volume index (PVI), compliance or Rout. An exponential correlation was found when plotting beta waves against the sum of conductance to outflow and compliance calculated by PVI method (r = 0.79). Patients with the so-called normal pressure hydrocephalus syndrome have different ICP and CSF dynamic profiles. Additional studies taking into consideration these differences are necessary before defining the sensitivity, specificity and predictive value of ICP monitoring and CSF studies in selecting appropriate candidates for shunting.