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P Vainio

Publications and source records attributed to P Vainio.

At least 37 records · Page 2Linked to original sources
PubMed1998

Recurrent seizures may cause hippocampal damage in temporal lobe epilepsy.

OBJECTIVE: To investigate whether recurrent seizures cause hippocampal damage in temporal lobe epilepsy (TLE). PATIENTS: Eighteen patients with newly diagnosed cryptogenic TLE, 14 patients with chronic well-controlled cryptogenic TLE, 32 patients with chronic drug-resistant cryptogenic TLE, and 25 healthy subjects were studied. MEASUREMENTS: Hippocampal MRI volumetry and T2 relaxometry were used. RESULTS: Chronic drug-resistant patients with seizure focus in the left temporal lobe had an 18% smaller left hippocampus and chronic drug-resistant patients with seizure focus in the right temporal lobe had a 14% smaller right hippocampus than did the control group (p < 0.05). Chronic drug-resistant patients with seizure focus on the left side had longer T2 relaxation times in the body of the left hippocampus than did the control group (p < 0.001) and chronic drug-resistant patients with seizure focus on the right side had longer T2 relaxation times in the body of the right hippocampus than did the control subjects (p < 0.01). In all patients with a left seizure focus, the left hippocampal volume correlated inversely with the estimated total number of partial (r = -0.391, p < 0.01) or generalized (r = -0.312, p < 0.05) seizures the patient had experienced. The prolongation of the left T2 relaxation time in the body of the hippocampus correlated with the total number of both partial (r = 0.670, p < 0.001) and generalized (r = 0.481, p < 0.001) seizures and with the duration of TLE symptoms (r = 0.580, p < 0.001). CONCLUSIONS: In patients with cryptogenic epilepsy, recurrent seizures may cause damage to the hippocampus throughout the lifetime of the patient.

Adolescent↗
PubMed1998

MR volumetric analysis of the human entorhinal, perirhinal, and temporopolar cortices.

PURPOSE: Our purpose was to investigate the normal volumes of the human entorhinal, perirhinal, and temporopolar cortices on MR imaging studies using a customized program. METHODS: We designed a protocol in which the volumes of the entorhinal, perirhinal, and temporopolar cortices were determined from coronal MR images using anatomic landmarks defined on the basis of cytoarchitectonic analyses of 49 autopsy cases. MR volumetry of these cortical areas was performed in 52 healthy volunteers. RESULTS: The overall mean volumes were 1768 +/- 328 mm3/1558 +/- 341 mm3 (right/left) for the entorhinal cortex, 2512 +/- 672 mm3/2572 +/- 666 mm3 for the perirhinal cortex, and 2960 +/- 623 mm3/3091 +/- 636 mm3 for the temporopolar cortex. The right entorhinal cortex was 12% larger than the left. The volume of the temporopolar cortex was reduced bilaterally by 13% in the older age group compared with younger subjects, while the volumes of the entorhinal and perirhinal cortices were unaffected by age. There were no differences between men and women in the volumes of any of the three cortices. CONCLUSION: Our method provides a tool by which to measure volumes of the entorhinal, perirhinal, and temporopolar cortices on coronal MR images.

Adolescent↗
PubMed1997

MRI volumetry of the hippocampus: the effect of slice thickness on volume formation.

The hippocampus is a mesial temporal lobe structure of complex shape and the main locus of temporal lobe epilepsy and also affected early in Alzheimer's disease. Magnetic resonance imaging of the hippocampus has been found to be a helpful diagnostic tool for these conditions. Measurement of hippocampal volumes has been found to be not only the most accurate approach to evaluation of the hippocampal pathology, but the most demanding and time consuming as well. One of the factors contributing to this is the slice thickness-the thinner the slice, the more time is required. On the other hand, it has been hypothesized, that the use of thick slice would result in volume aberrations due to, for example, the volume averaging effect. We therefore measured the volumes of the hippocampus on coronal slices in 10 healthy, young control subjects using slice thicknesses of 1, 3 and 5 mm, and evaluated the effect of the slice thickness on the volume formation. No significant difference between the volumes of the hippocampus using different thicknesses was found. Therefore, it appears that use of the thick slices would not necessarily introduce systematic bias to the volumetric measurement. Yet, we do not feel compelled to advise the use of "thick" slices either, since the use of "thin" slices seems the most authoritative and less vulnerable to being affected by a single false estimate.

Adult↗
PubMed1997

MRI volumetry and T2 relaxometry of the amygdala in newly diagnosed and chronic temporal lobe epilepsy.

Little is known about the appearance and severity of amygdaloid damage in temporal lobe epilepsy, particularly in its early stages. In the present magnetic resonance imaging study, we measured amygdaloid volumes and T2 relaxation times in 29 patients with newly diagnosed and in 54 patients with chronic temporal lobe epilepsy. The control population included 25 normal subjects. In the newly diagnosed patients, the mean amygdaloid volume did not differ from that in controls. Also, in the chronic patients the mean amygdaloid volume did not differ from that in controls or in newly diagnosed patients. However, in 19% of the chronic patients the amygdaloid volume was reduced by at least 20%. Moreover, in all of the epilepsy patients, both chronic and newly diagnosed, we found an inverse correlation between the number of epileptic seizures the patient had experienced and the amygdaloid volume on the focal side (focus on the left, r = -0.371, P < 0.01; focus on the right, r = -0.348, P < 0.05). The mean T2 relaxation time in newly diagnosed or chronic patients did not differ from each other or from control values. However, the T2 relaxation time of the left amygdala was > or = 111 msec (i.e., > or = 2 S.D. over the mean T2 time of the left amygdala in control subjects) in seven (10%) patients, one of which was newly diagnosed and six were chronic. The T2 time of the right amygdala was prolonged in eight (12%) patients, three of which were newly diagnosed and five were chronic. We did not find any clear asymmetries in amygdaloid volumes or T2 relaxation times between the ipsilateral and contralateral sides relative to seizure focus. According to the present findings, signs of amygdaloid damage were observed in approximately 20% of patients with temporal lobe epilepsy, most of which had chronic epilepsy.

Adolescent↗
PubMed1996

Automated classification of human brain tumours by neural network analysis using in vivo 1H magnetic resonance spectroscopic metabolite phenotypes.

We present a novel method to integrate in vivo nuclear magnetic resonance spectroscopy (MRS) information into the clinical diagnosis of brain tumours. Water-suppressed 1H MRS data were collected from 33 patients with brain tumours and 28 healthy controls in vivo. The data were treated in the time domain for removal of residual water and a region from the frequency domain (from 3.4 to 0.3 p.p.m.) together with the unsuppressed water signal were used as inputs for artificial neural network (ANN) analysis. The ANN distinguished tumour and normal tissue in each case and was able to classify benign and malignant gliomas as well as other brain tumours to match histology in a clinically useful manner with an accuracy of 82%. Thus the present data indicate existence of tumour tissue-specific metabolite phenotypes that can be detected by in vivo 1H MRS. We believe that a user-independent ANN analysis may provide an alternative method for tumour classification in clinical practice.

Astrocytoma↗
PubMed1996

Slow-wave activity in the spectral analysis of the electroencephalogram and volumes of hippocampus in subgroups of Alzheimer's disease patients.

This study examined patients who fulfilled the National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association Work Group criteria for probable Alzheimer's disease (AD; n = 35) and controls for magnetic resonance imaging and psychometric data (n = 16) and for quantitative electroencephalogram data (n = 34). A cluster analysis performed on neuropsychological variables identified 2 AD subgroups: The AD1 group (n = 12) had impaired memory and executive functions but preserved verbal and visuospatial functions. The AD2 group (n = 23) had global impairment. The AD2 group had higher theta amplitude in the temporo-occipital, centroparietal, and frontal derivation and lower peak and mean frequency than the AD1 group or controls. Both AD groups had more severe memory deficits and clearly smaller hippocampal volumes than controls. This may implicate that the degree of damage in ascending activating systems differs in these subgroups, although the damage in the hippocampus is equal.

Aged↗
PubMed1996

Athletic heart: a metabolic, anatomical, and functional study.

Previous studies have suggested a reduced glucose uptake by the athlete's heart at rest. To examine whether there is a compensatory increase in the myocardial fatty acid utilization, we studied nine male endurance-trained athletes (age 26 +/- 2 yr, VO2max 60 +/- 1 ml.kg-1.min-1, mean +/- SEM) and eight sedentary subjects (age 26 +/- 1 yr, VO2max 38 +/- 2 ml.kg-1.min-1) by single photon emission tomography using 123I-heptadecanoic acid (HDA) and mathematical modeling. Magnetic resonance imaging (MRI) and echocardiography were performed for the measurements of cardiac dimensions and left ventricular (LV) mass. No significant differences were found in the myocardial HDA beta-oxidation index (5.2 +/- 2.0 vs 7.4 +/- 1.6 mumol.min-1.100 g-1, P = NS) between endurance-trained and sedentary subjects. Fractional amounts of HDA beta-oxidation, backdiffusion, and esterification were also similar. In MRI study, LV mass was greater in the trained subjects (213 +/- 9 vs 179 +/- 10 g, P < 0.01) and in particular, LV long-axis diameter measured from the mitral valve level to the apex was increased (102 +/- 2 vs 88 +/- 2 mm, P < 0.001, trained vs sedentary subjects). VO2max correlated with LV long-axis diameter (r = 0.77, P < 0.001). In contrast to our hypothesis, myocardial HDA utilization was not enhanced in endurance-trained athletes at rest. Increases in LV mass and especially in LV long-axis diameter were observed in the athletes, indicating LV longitudinal remodeling.

Adult↗
PubMed1996

Hippocampal volumes in Alzheimer's disease, Parkinson's disease with and without dementia, and in vascular dementia: An MRI study.

Hippocampal atrophy detected by volumetric MRI is a sensitive feature of early Alzheimer's disease (AD), but there are no studies evaluating hippocampal atrophy by MR volumetry in other dementing diseases. We therefore compared hippocampal volumes in a total of 113 subjects: 50 patients with mild to moderate AD, 9 patients with vascular dementia (VaD), 12 patients with idiopathic Parkinson's disease (PD) without dementia, 8 patients with PD and dementia (PDD), and 34 elderly control subjects. Thin, coronal, contiguous images were obtained by a 1.5-T MR imager. All patient groups had significantly smaller volumes of the hippocampus compared with the control group. In the PDD group, the absolute volumes were even smaller than in the AD group. In the PD group, the volumes were diminished to a lesser but significant extent. The volumes in the VaD group varied: of nine patients, two had no atrophy, three had unilateral, and four had bilateral atrophy. We postulate that hippocampal atrophy does not seem to be a specific phenomenon of dementia in AD but also occurs in VaD and PDD, and even in PD when no dementia is present. However, coexistence of AD pathology in our PD and VaD patients cannot be ruled out. Further studies with access to neuropathologic data are needed.

Aged↗
PubMed1996

Severity of hippocampal atrophy correlates with the prolongation of MRI T2 relaxation time in temporal lobe epilepsy but not in Alzheimer's disease.

We analyzed hippocampal volumes and T2 relaxation times by MRI from 78 control subjects, 24 patients with temporal lobe epilepsy, and 55 patients with Alzheimer's disease (AD). In the epilepsy group, the hippocampal volumes were 27% smaller than in control subjects (p < 0.001). The T2 relaxation times were prolonged (8 to 20 ms compared with control subjects) in the head, body, and tail portions of the hippocampus on the focal side (p < 0.01) and also on the contralateral side (p < 0.05) compared with control subjects. In the epilepsy group, the prolongation of T2 relaxation time correlated inversely with the hippocampal volume (p < 0.05). In the AD group, the hippocampal volumes were 35% smaller than in control subjects (p < 0.01). The T2 relaxation times were slightly prolonged (5 to 6 ms) in the head and tail portions of the right hippocampus (p < 0.01), but the T2 relaxation times did not correlate with the hippocampal volumes. These data show that the degree of prolongation of T2 relaxation time is associated with severity of hippocampal atrophy in temporal lobe epilepsy but not in AD.

Adult↗
PubMed1996

MRI in obstetrics: a supplementary method for ultrasonography.

The use of magnetic resonance imaging (MRI) as a complementary diagnostic method was evaluated in a group of 36 complicated pregnancies during the last trimester. Most of the examinations were carried out by two specific MRI sequences, the T1-weighted gradient echo FLASH sequence (TR 120, TE 12) and the T2-weighted fast-spin echo sequence (TR 2000, TE 90). Information additional to that obtained by ultrasonic diagnosis was obtained by MRI in 16 of the 25 cases of foetal malformation and in 5 of the 11 cases with other obstetric problems. Foetal curarization was not necessary in most of the cases. A good MRI technique, for selected obstetric problems and when used in combination with detailed antepartal ultrasonic examinations, can give useful diagnostic information to an obstetrician.

Adult↗
PubMed1995

MRI of amygdala fails to diagnose early Alzheimer's disease.

We evaluated the ability of MRI of the amygdala to diagnose early Alzheimer's disease (AD). The volume of the amygdala was measured in 54 patients with probable AD, 38 subjects with age-associated memory impairment (AAMI), 34 cognitively normal elderly controls (OC) and 20 young controls (YC). The amygdala was atrophied in all the elderly study groups with atrophy being strongest in the AD group (p < 0.0001). The OC and AAMI groups differed from the YC group (p < 0.05) but not from each other. There was a major overlap between the study groups. The volumes also correlated with age (p < 0.0001) and gender (p < 0.001). A correct classification was achieved in 74% of AD patients and the non-demented elderly subjects. Thus, MRI of amygdala fails to diagnose AD accurately.

Adult↗
PubMed1995

Radiation-induced changes in human brain metabolites as studied by 1H nuclear magnetic resonance spectroscopy in vivo.

PURPOSE: External radiation therapy for brain tumors exposes healthy areas of brain to considerable doses of radiation. This may cause cognitive and psychological impairment, which indicate neuronal dysfunction. 1H-magnetic resonance spectroscopy (MRS) was used to study brain metabolites in the adjacent regions 0.5-13 years after exposure to therapeutic irradiation. METHODS AND MATERIALS: Eight patients with irradiated brain tumors were examined by means of in vivo 1H-MRS using a point-resolved spectroscopy (PRESS) sequence with echo times of 60 or 270 ms. The metabolites were quantified by using brain water concentration as internal reference. The volume of interest (VOI) was positioned in irradiated brain areas excluding, however, scar and recurrent tumor. The respective radiation doses were measured based on radiation therapy plans, simulator films, and localization MR images. RESULTS: The concentration of the neuron-specific metabolite N-acetyl-L-aspartate (NAA) was 13.2 +/- 1.4 mmol/l in controls, whereas it was reduced in the brains of treated patients to 8.6 +/- 0.9 mmol/l (total radiation dose 59-62 Gy). Concentrations of creatine and choline-containing compounds were unchanged. The T2 of water was longer in irradiated than in unexposed brain areas. CONCLUSION: Therapeutic brain irradiation causes neuronal damage, which is reflected by reduction of N-acetyl-L-aspartate (NAA) concentrations. 1H-MRS could serve clinically as a means of evaluating adverse effects in the central nervous system, enabling intervention and rehabilitation.

Adult↗
PubMed1995

Volumes of hippocampus, amygdala and frontal lobes in the MRI-based diagnosis of early Alzheimer's disease: correlation with memory functions.

We studied the usefulness of measuring volumes of the hippocampus, amygdala and frontal lobes with coronal magnetic resonance imaging (MRI) scans in the diagnosis of early Alzheimer's disease (AD). We examined 32 patients diagnosed according to the NINCDS-ADRDA criteria of probable AD and 16 age-matched healthy cognitively normal controls. The AD patients had mild dementia with a mean score of 22.8 in the Mini-Mental Status Examination (MMSE). We used a 1.5 T magnetic resonance imager and normalized the volumes for brain area. The AD patients had significantly smaller volumes of the right and the left hippocampus (-38%) (ANOVA, p < 0.0001) and the left frontal lobe (-16%, p < 0.05) compared to controls. The reductions in volumes of the right frontal lobe (-13%), the right amygdala (-14%) or the left amygdala (-18%) were not statistically significant. In the discriminant function analysis which included the volumes of the hippocampus, amygdala, and the frontal lobes and age, the volumes of the left and right hippocampus, the left and right frontal lobe, and the right amygdala entered the model and we could correctly classify 92% of the subjects into AD and control groups (Chi-square 42.6, df 5, p < 0.001). By using the volumes of the hippocampus, the frontal lobes or the amygdala on their alone, the correct classification was achieved in 88%, 65% and 58% of the subjects, respectively. In addition, in AD patients the volumes of the left hippocampus correlated significantly with the MMSE score and with immediate and delayed verbal memory; the smaller the volume the more impaired was their performance. Our data indicate that measurements of volumes of the hippocampus might be useful in diagnosis of early AD.

Aged↗
PubMed1995

Volumes of hippocampus, amygdala and frontal lobe in Alzheimer patients with different apolipoprotein E genotypes.

An increased frequency of apolipoprotein E E4 allele has been reported in patients with late onset Alzheimer's disease. Apolipoprotein E participates in the transport of cholesterol and other lipids and interferes with the growth and regeneration of both peripheral and central nervous system tissues during development and after injury. Apolipoprotein E is also implicated in synaptogenesis. Apolipoprotein E isoforms differ in binding to amyloid-beta-protein and tau protein in vitro. Here, we wanted to study the effect of apolipoprotein E genotype on the magnitude of damage in the hippocampus, where a marked synapse loss exists in Alzheimer's disease. We measured by magnetic resonance imaging the volumes of the hippocampus, amygdala, and frontal lobes in the three Alzheimer subgroups: patients with 2, 1 or 0 E4 alleles. We also investigated the profile of deficits on tests assessing memory, language, visuospatial, executive, and praxic functions of these Alzheimer subgroups. All Alzheimer patients were at early stage of the disease. We found that Alzheimer patients with E4/4 genotype (N = 5) had smaller volumes of the hippocampus and the amygdala than those with E3/4 (N = 9) and those with E3/3 or E2/3 (N = 12). The difference was significant for the right hippocampus (-54% of control) and the right amygdala (-37% of control). The volumes of the frontal lobes were similar across the Alzheimer subgroups. The patients with E4/4 also showed lowest scores on delayed memory tests and differed from E3/3, 3/2 patients in the list learning test (< 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Comparison of different models for interpreting bone mineral density measurements using DXA and MRI technology.

Bone mineral density measurements using dual X-ray absorptiometry (DXA) are commonly expressed as areal density (g/cm2). However, areal BMD (BMDareal) is dependent on bone size and this can lead to erroneous interpretations of BMD values. We have previously presented a simple method for calculating apparent volumetric bone mineral density (BMDvol) using ancillary DXA-derived data. In the present study we tested the validity of our model using in vivo volumetric data obtained from magnetic resonance imaging (MRI) of lumbar vertebrae. BMDareal and BMDvol of L3 were measured from sixteen pairs of identical twins (24 men, 8 women), aged 25-69 years. The dimensions of the lumbar vertebra L3 were measured from MR images and BMD values were corrected for these dimensions. The DXA-derived apparent volumetric bone mineral density (BMDvol) correlated moderately with MRI-derived BMDs (r values from 0.665 to 0.822). In contrast to BMDareal, BMDvol and MRI-derived BMDs were not related to body size variables. All these volume-corrected BMDs diminished the erroneous effect of vertebral size on areal BMD. We conclude that the simple DXA-derived BMDvol can be used for normalization of bone mineral density values in subjects of different body sizes, and especially in growing children.

Absorptiometry, Photon↗
PubMed1995

Craniomandibular disorders and skeletal mineral status.

Values for bone mineral density of the femoral neck and lumbar spine were determined by dual-energy x-ray absorptiometry for 355 postmenopausal women 48 to 56 years of age. The bone mineral density in three regions of the mandible was measured by quantitative computed tomography for 77 of the 355 women. Existing symptoms of craniomandibular dysfunction were recorded in both an anamnestic inquiry and a clinical examination. The purpose of this study was to determine whether the bone mineral density of the skeleton and mandible is associated with symptoms of craniomandibular dysfunctions. The results suggest that the habits and conditions that provoke development of general bone loss in the skeleton may disturb the functional harmony of the masticatory system and, thus, increase the possibility for craniomandibular disorders (CMD).

Absorptiometry, Photon↗
PubMed1995

Abnormal regional benzodiazepine receptor uptake in the prefrontal cortex in patients with panic disorder.

The neuroanatomical networks involved in the initiation of panic attack and the maintenance of panic disorder are poorly understood. This study aimed to elucidate the possible abnormalities in benzodiazepine receptor uptake in the brain of patients with panic disorder. Seventeen unmedicated patients with panic disorder were investigated using 123I-iomazenil single photon emission tomography (SPET). Seventeen healthy age- and sex-matched volunteers served as controls. The SPET scan was taken 90 min after injection of tracer. Eleven of 17 patients (65%) showed an increased (> 2 S.D. higher than the mean of the controls) right-to-left ratio of benzodiazepine receptor uptake in the prefrontal cortex. Also, the mean right-to-left ratio of benzodiazepine receptor uptake in all 17 patients with panic disorder was higher than in the controls (P < 0.001). Our SPET study demonstrated focally altered benzodiazepine receptor uptake in the prefrontal cortices in patients with panic disorder. Magnetic resonance imaging indicated that the affected region was located in the right middle and inferior frontal gyri. The deterioration in information processing in the right prefrontal cortex may be implicated in the generation of panic disorder.

Female↗