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Biomedical subjects

K Partanen

Publications and source records attributed to K Partanen.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1997

Lumbar disc herniations in children: a long-term clinical and magnetic resonance imaging follow-up study.

To determine the long-term outcome of 12 youthful patients with lumbar disc herniation, who, at the time of surgery, were 15 years old and younger (mean age at operation 14.3 years), we assessed their current clinical condition (mean follow-up time 6 years) with a questionnaire inquiring about symptoms and disability, and radiologically with an MRI of the lumbar spine. Clinically, only five patients (40%) were totally asymptomatic and seven patients (60%) had recurring symptoms, both and disability. On MRI, seven patients (60%) had persistent stenosing changes at the operated disc levels and eight patients (65%) also had disc degeneration at other lumbar levels. Despite the symptoms and quite severe radiological findings, the long-term outcome was assessed as good or moderate in eleven patients (90%). As far as comparisons are reasonable, our results appear somewhat less favourable than those in two previous paediatric series, but they agree with those in two recent large series of adults.

Adolescent↗
PubMed1997

Cerebral blood flow changes associated with fetal intracranial hemorrhages.

UNLABELLED: BACKGROUND AND MATERIAL: In order to evaluate cerebral blood flow changes associated with fetal intracranial hemorrhages, ultrasound and MRI examinations were carried out in four pregnancies with this complication. RESULTS: Increased resistance indices of the blood flow profile of the middle cerebral artery were detected in three of the fetuses, two of them presenting retrograde diastolic flow. Flow became normalized in one case within four weeks, changing on the contralateral side to an increased diastolic flow pattern. CONCLUSION: Increased intracranial pressure can cause these flow changes, but cerebral blood flow autoregulation need not be completely ruined in this complication.

Cerebral Hemorrhage↗
PubMed1997

Decline of frontal lobe functions in subjects with age-associated memory impairment.

OBJECTIVE: To assess frontal lobe functions of subjects with age-associated memory impairment (AAMI) and to examine whether performance on neuropsychological tests is correlated with the volume of the frontal lobes in magnetic resonance imaging. DESIGN: Cross-sectional two-group comparison. SETTING: The Memory Research Clinic of Kuopio University and the Magnetic Resonance Imaging Center of Kuopio University Hospital. PARTICIPANTS: Ninety subjects (mean age, 70.5 years), 43 with AAMI diagnosed according to National Institute of Mental Health criteria and 47 age-matched healthy controls. MEASUREMENTS: Four neuropsychological tests were used to assess frontal lobe function: Verbal Fluency Test (VFT), Modified Wisconsin Card Sorting Test (WCST), Trail Making Test (TMT), and Stroop Test (ST). A 1.5-T magnetic resonance imager was used for volume measurements. RESULTS: The AAMI subjects scored significantly worse on the WCST, ST, and TMT compared with controls (ANCOVA, adjusted for age and education, p < 0.05). The frontal lobe volumes did not differ between AAMI subjects and controls. CONCLUSIONS: AAMI subjects appear to be impaired not only in tests assessing memory but also in tests of executive functions. This finding agrees with previous reports suggesting a central role for frontal dysfunction in memory loss of elderly people.

Aged↗
PubMed1997

Ultrasonic and magnetic resonance imaging of fetal sacrococcygeal teratoma.

OBJECTIVE: To evaluate ultrasonic and magnetic resonance imaging (MRI) and Doppler examination in fetal sacrococcygeal teratoma (SCT), in respect to the postnatal findings and histological type of the tumor. STUDY DESIGN: Nine pregnancies complicated by histologically mature fetal sacrococcygeal teratoma in four cases and by immature/malignant teratoma in five cases. Transabdominal ultrasonic imaging and Doppler velocity waveforms were recorded during the second or last trimester in all cases, first trimester ultrasound examination was carried out in six cases and last trimester MRI in five cases. These findings were compared with postnatal and operative findings of the children. RESULTS: Ultrasound examination did not reveal intrapelvic parts of SCT, but this was possible by MRI. Velocity waveforms of the tumor arteries were similar in all histological types and the resistance index varied from 60 to 70. The mean gestational age at antepartal diagnosis was 25.2 weeks. Large tumor size with relatively large proportion of solid components was often recognized in cases with malignant/immature histology. CONCLUSIONS: Antepartal MRI is useful for examination of fetal SCT, but reliable differentiation of mature and immature SCT is not possible antepartally.

Female↗
PubMed1997

Fetal intracranial hemorrhage. Imaging by ultrasound and magnetic resonance imaging.

OBJECTIVE: To describe the magnetic resonance imaging (MRI) findings associated with fetal intracranial hemorrhage and to compare them with ultrasound findings. STUDY DESIGN: In four pregnancies complicated by fetal intracranial hemorrhage, fetal imaging was carried out using T2-weighted fast spin echo sequences and T1-weighted fast low angle shot imaging sequences and by transabdominal ultrasonography. RESULTS: An antepartum diagnosis of hemorrhage was made by ultrasound in one case and by MRI in two. Retrospectively, the hemorrhagic area could be identified from the MRI images in an additional two cases and from the ultrasound images in one case. In the cases of intraventricular hemorrhage, the MRI signal intensity in the T1-weighted images was increased in the hemorrhagic area as compared to the contralateral ventricle and brain parenchyma. In a case with subdural hemorrhage, T2-weighted MRI signals from the hemorrhagic area changed from low-to high-intensity signals during four weeks of follow-up. Better imaging of the intracranial anatomy was possible by MRI than by transabdominal ultrasonography. CONCLUSION: MRI can be used for imaging and dating fetal intracranial hemorrhages. Variable ultrasound and MRI findings are associated with this complication, depending on the age and location of the hemorrhage.

Cerebral Hemorrhage↗
PubMed1996

Interobserver variability in measuring the dimensions of the abdominal aorta: comparison of ultrasound and computed tomography.

OBJECTIVES: To examine the interobserver variability in measuring the abdominal aorta by ultrasound (US) and computed tomography (CT). DESIGN: A prospective clinical study in a university hospital. MATERIALS: Thirty-three patients whose abdominal aortas were scanned both with CT and US as a part of aneurysm investigation or for a variety of other reasons. METHODS: Three radiologists measured abdominal aortic diameters by US and CT. The interobserver differences (IOD) in US and CT and intraobserver differences for CT-US-pairs were analysed by various statistical methods. A new concept of "clinically acceptable difference" (CAD) was adopted denoting differences of less than 5mm. RESULTS: The IOD in US was 2mm or less in 65% of the anteroposterior and 61% of the transverse measurements and 5mm or more in 11% of the anteroposterior and 14% in the transverse measurements in 102 observer pairs for all aortas. The IODs were significantly larger in measuring the aneurysmal aortas compared with normal aortas (p < 0.001). The CAD-value for the aneurysmal aortas was 84% in the anteroposterior and 82% in the transverse directions. In CT the IODs were 2mm or less in 62% of the anteroposterior and 66% of the transverse measurements and 5mm or more in 12% of both anteroposterior and transverse measurements in 94 observer pairs for all aortas. The CAD-value in the aneurysmal aortas was 91% in the anteroposterior and 85% in the transverse directions. There was no significant difference between the US and CT CAD-levels. The absolute CT-US difference of an individual observer was 2mm or less in 54%, 5mm or more in 17% and 10mm or more in 2% of the anteroposterior measurements in the 95 CT-US pairs. In the transverse direction the corresponding figures were: 2mm or less in 63%, 5mm or more 13% and 10mm or more in 2% of the pairs. The diameters obtained by US were smaller in 84% of the cases compared with those of CT in measuring the maximum aortic diameter in anteroposterior direction, whereas the same figure for the transverse measurements was 59%. CONCLUSIONS: Both US and CT measurements are subject to significant interobserver variability that must be taken into account in the clinical follow-up of small abdominal aortic aneurysms and in screening studies. Neither of these methods can be considered as a 'gold standard'.

Aorta, Abdominal↗
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

SPECT and MRI analysis in Alzheimer's disease: relation to apolipoprotein E epsilon 4 allele.

OBJECTIVES: The epsilon 4 allele of apolipoprotein E (ApoE) is a risk factor for late onset Alzheimer's disease. ApoE is present in senile plaques, neurofibrillary tangles, and cerebrovascular amyloid, and it is implicated in synaptogenesis. The effect of ApoE polymorphism on the volumes of hippocampus, amygdala, and frontal lobe was studied. The hypothesis was that the patients with Alzheimer's disease carrying the epsilon 4 allele have more pronounced atrophy. The relation of ApoE and cerebral blood flow on cortical areas was also assessed. METHODS: Fifty eight patients with Alzheimer's disease at the early stage of the disease and 34 control subjects were studied. Patients with Alzheimer's disease were divided into subgroups according to the number of the epsilon 4 alleles. Volumes were measured by MRI and regional cerebral blood flow ratios referred to the cerebellum were examined by 99mTc-HMPAO SPECT. ApoE genotypes were determined by digestion of ApoE polymerase chain reaction products with the restriction enzyme Hha1. RESULTS: patients with Alzheimer's disease had smaller volumes of hippocampi and amygdala compared with control subjects, and the patients with Alzheimer's disease homozygous for the epsilon 4 allele had the most prominent volume loss in the medial temporal lobe structures. The frontal lobe volumes did not differ significantly. All patients with Alzheimer's disease had bilateral temporoparietal hypoperfusion and the subgroups with one or no epsilon 4 alleles also had frontal hypoperfusion compared with control subjects. The occipital perfusion ratios tended to decrease with increasing number of epsilon 4 alleles. CONCLUSIONS: Patients with Alzheimer's disease homozygous for the epsilon 4 allele seem to have severe damage in the medial temporal lobe structures early in the disease process and differ from the patients with Alzheimer's disease with one or no epsilon 4 alleles.

Age of Onset↗
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↗
PubMed1996

Familial abdominal aortic aneurysms: screening of 71 families.

OBJECTIVE: To find out the local prevalence of familial abdominal aortic aneurysms. DESIGN: Retrospective open study. SETTING: University hospital, Finland. SUBJECTS: 71 families of patients operated on for abdominal aortic aneurysm. INTERVENTIONS: Ultrasound screening, personal interviews and study of population registers, death certificates and hospital records. MAIN OUTCOME MEASURES: The diagnosis of asymptomatic abdominal aortic aneurysms. RESULTS: 148 of the 291 patients operated on replied to our letter (51%). The ultrasound examination was carried out on 123 siblings and detected abdominal aortic aneurysm in one sister (1/78 about 1%) and four brothers (4/45 about 9%). By the other methods data were obtained on 77 siblings (54 men and 23 women) of whom two sisters and six brothers were found to have abdominal aortic aneurysms. When the figures for the 71 families were combined, 10% of the brothers (10/99) and 3% of the sisters (3/101) had abdominal aortic aneurysms. These siblings were from 11 different families and so the prevalence of families with at least two affected persons was 16% (11/71). The index patient in 65 families was male and the prevalence of risk families (with two or more cases of aneurysm) in this group was 15% (10/65). The index case was a woman in six families giving a prevalence of 33% (2/6) (p = 0.2 between the groups). CONCLUSION: The screening of families of patients with abdominal aortic aneurysms should be restricted to the brothers of these patients.

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

Hippocampal atrophy, acute THA treatment and memory in Alzheimer's disease.

We designed the present study to investigate the hypothesis that progression of hippocampal pathology may decrease the therapeutic effects of anti-cholinesterase drug, tetrahydroaminoacridine, on memory functioning in Alzheimer's disease (AD) patients. Memory, visuoconstructive, executive and vigilance functions were assessed after administration of placebo (p.o.; two placebo sessions) and tetrahydroaminoacridine (one session for 25 and 75 mg, p.o.). Eight patients performed better on list learning test during tetrahydroaminoacridine 75 mg than after placebo or tetrahydroaminoacridine 25 mg. The responders performed during baseline examination better than the non-responders in executive and some declarative memory functions, and had higher MMSE scores than the non-responders. The responders had larger left and right hippocampi than the non-responders. The hippocampal volume correlated with list learning performance. The results suggest that severe hippocampal atrophy may block memory improving effect of an anticholinesterase drug, tetrahydroaminoacridine.

Alzheimer Disease↗
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

Habituation of auditory N100 correlates with amygdaloid volumes and frontal functions in age-associated memory impairment.

We studied the habituation of auditory N100 responses in subjects with age-associated memory impairment (AAMI) and in healthy age-matched volunteers. The findings were correlated with volumes of the amygdala, hippocampus, and frontal lobe measured by magnetic resonance imaging (MRI), as well as with subjects' performance on tests assessing frontal lobe functions and memory. Habituation of N100 did not differ across AAMI subjects and controls. However, in AAMI subjects there was a significant correlation between habituation of N100 and volumes of the amygdala; the more reduced habituation, the smaller volume. In addition, decline in habituation of N100 correlated with impaired performance on a visual memory test (Heaton Visual memory test (Heaton Visual Retention Test; r = 0.77; p < 0.001) and impairment on tests assessing frontal functions (Verbal Fluency, Trail Making Test, and Stroop). Habituation of N100 was not related to age or sex. To our knowledge this is the first study to demonstrate a relationship between habituation of evoked responses, MRI volumetric measures, and performance on psychometric tests. The results suggest that impaired memory and frontal lobe functions in AAMI subjects may be associated with poor habituation of N100. Since habituation reflects focusing of attention to relevant features of stimuli, impairment of this mechanism and subsequent defective memory trace formation may contribute to the observed deficits on memory tests.

Aged↗