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Biomedical subjects

K Partanen

Publications and source records attributed to K Partanen.

At least 37 records · Page 2Linked to original sources
PubMed2000

Late correlative imaging findings of previous acute infective spondylitis.

PURPOSE: To evaluate late correlative imaging findings in relation to clinical outcome in persons with previous acute infective spondylitis, the authors performed bone and leukocyte scintigraphy (planar and SPECT imaging) and magnetic resonance imaging of the spine in nine patients (two men, seven women; mean age, 66 years; age range, 57 to 84 years) 3.1 years (range, 0.9 to 6.2 years) after the acute disease. METHODS: All images were evaluated visually. The relevant uptake on SPECT images was also quantitated using an adjacent normal vertebral body as the reference area. RESULTS: Except for one patient, all other patients had increased uptake in the affected vertebra on bone scintigraphy [corrected]. In leukocyte scintigraphy, clearly decreased uptake was noted quantitatively in six of the seven patients who underwent SPECT. On the magnetic resonance and computed tomographic scans, the typical findings were destruction of intervertebral disks and compression deformities of vertebral bodies, but there was high interindividual variance of other findings, such as osteophytes, spondylolisthesis, increased vertebral fat content, and postoperative changes. These data show that nearly all patients with previously acute infective spondylitis have gross abnormal anatomic and functional imaging findings years after the acute disease, despite good clinical outcome [corrected]. CONCLUSIONS: The utility of bone and leukocyte scans in the diagnosis of reactivated spondylitis is limited, and incidentally observed abnormal imaging findings in asymptomatic patients with known previous spondylitis should be interpreted with caution.

Aged↗
PubMed2000

Diagnosing fetal urinary tract abnormalities: benefits of MRI compared to ultrasonography.

BACKGROUND: To compare antepartum ultrasonography with magnetic resonance imaging for prenatal diagnosis of malformations in the fetal urinary tract in high risk patients during the last trimester. MATERIALS AND METHODS: The study involved 22 women and 24 fetuses with either severe oligohydramnios or ultrasonographically or clinically suspected abnormality of urinary tract. Ultrasound examination was carried out with 5 MHz abdominal convex probe and magnetic resonance imaging with superconductive 1.5 T equipment. Postnatal findings were used as reference. RESULTS: Correct diagnosis of urinary tract anomaly was done in 15 fetuses on ultrasound and in 20 fetuses on magnetic resonance imaging. Both methods enabled correct diagnosis in 12, only ultrasound in three and only magnetic resonance imaging in eight fetuses. Both methods imaged equivocally in one case. The additional information by magnetic resonance imaging was gained from five fetuses out of 12 pregnancies with oligohydramnios and from three fetuses out of ten pregnancies with normal amount of amniotic fluid. CONCLUSIONS: MRI is a valuable additional method to ultrasonography of fetal urinary tract if resolution of ultrasound is impaired for reason of oligohydramnios or technical deterioration.

Congenital Abnormalities↗
PubMed2000

MR imaging of the hippocampus in normal pressure hydrocephalus: correlations with cortical Alzheimer's disease confirmed by pathologic analysis.

BACKGROUND AND PURPOSE: MR studies have shown hippocampal atrophy to be a sensitive diagnostic feature of Alzheimer's disease (AD). In this study, we measured the hippocampal volumes of patients with a clinical diagnosis of normal pressure hydrocephalus (NPH), a potentially reversible cause of dementia when shunted. Further, we examined the relationship between the hippocampal volumes and cortical AD pathologic findings, intracranial pressure, and clinical outcomes in cases of NPH. METHODS: We measured hippocampal volumes from 37 patients with a clinical diagnosis of NPH (27 control volunteers and 24 patients with AD). The patients with NPH underwent biopsy, and their clinical outcomes were followed for a year. RESULTS: Compared with those for control volunteers, the findings for patients with NPH included a minor left-side decrease in the hippocampal volumes (P < .05). Compared with those for patients with AD, the findings for patients with NPH included significantly larger hippocampi on both sides. Although not statistically significant, trends toward larger volumes were observed in patients with NPH who had elevated intracranial pressure, who benefited from shunting, and who did not display cortical AD pathologic findings. CONCLUSIONS: Measurements of hippocampal volumes among patients with a clinical diagnosis of NPH have clear clinical implications, providing diagnostic discrimination from AD and possibly prediction of clinical outcome after shunting.

Aged↗
PubMed2000

Verbal fluency activates the left medial temporal lobe: a functional magnetic resonance imaging study.

Verbal fluency tests (VFTs) are suggested to assess frontal lobe function. This view is supported by functional imaging studies that report left frontal activation during VFTs. VFTs require retrieval of semantically associated words from long-term memory storage. The neural networks that participate in this process, however, are largely unknown. These neural networks are of interest, given that patients with early Alzheimer's disease, typically without frontal pathology, are often impaired in VFTs. In the present study, functional magnetic resonance imaging was performed to determine brain activation areas during VFTs in young subjects. In the activation task, category fluency was contrasted with orderly listing of numbers. As judged from using this comparison, there was activation in the left medial temporal lobe, in the inferior frontal and retrosplenial cortices bilaterally, and in the left superior parietal lobule. Left medial temporal lobe activation was present in 13 of the 14 study subjects either in the hippocampal formation (11 of 14) or in the posterior parahippocampal gyrus (12 of 14). These results suggest that the medial temporal lobe is required for the process of retrieval by category. Functional magnetic resonance imaging combined with a category fluency task may provide a new method to study patients with early Alzheimer's disease.

Adult↗
PubMed1999

Vigabatrin, a gabaergic antiepileptic drug, causes concentric visual field defects.

OBJECTIVE: To determine whether there is a causal link between vigabatrin treatment and concentric visual field defects and to evaluate the prevalence of these visual field constrictions. BACKGROUND: While the GABAergic antiepileptic drug (AED) vigabatrin was being clinically developed, only rare cases (less than 1:1000) of symptomatic visual field constriction and retinal disorders were reported. During 1997 to 1998, concentric visual field constrictions were described in case reports of mostly drug-resistant epilepsy patients receiving vigabatrin concurrently with other AEDs. METHODS: Ophthalmologic tests including Goldmann perimetry were performed on 32 adult patients on long-term successful vigabatrin monotherapy (treatment duration 29 to 119 months) and on 18 patients on carbamazepine monotherapy (treatment duration 32 to 108 months). Eighteen healthy adults served as controls. RESULTS: None of the patients complained about vision problems when asked to participate into the study. Thirteen out of the 32 (40%) epilepsy patients treated with vigabatrin monotherapy had concentrically constricted visual fields (9% severely, 31% mildly constricted), whereas none of the carbamazepine monotherapy patients or normal controls presented with a visual field defect (chi-square test, p = 0.0001). The extents of the visual fields were significantly constricted in vigabatrin group as compared with the visual fields of the patients in carbamazepine group or healthy controls (analysis of variance, Scheffe F-test, significant at 99%). CONCLUSIONS: The use of vigabatrin seems to increase the risk of a unique and specific pattern of bilateral, mainly asymptomatic visual field constriction. This risk should be considered when using vigabatrin. Visual field testing should also be performed before treatment and during routine follow-up for patients on vigabatrin.

Adolescent↗
PubMed1999

Long-term clinical and magnetic resonance imaging follow-up assessment of patients with lumbar spinal stenosis after laminectomy.

STUDY DESIGN: A cross-sectional retrospective study to observe the correlation between postoperation findings shown on magnetic resonance imaging and clinical observations of 56 patients 10 years after laminectomy for lumbar spinal stenosis. OBJECTIVE: To evaluate the relation between postoperation findings on magnetic resonance imaging and surgical outcome in patients surgically treated for lumbar spinal stenosis. SUMMARY OF BACKGROUND DATA: Surgical management of lumbar spinal stenosis is based on the compression seen in radiologic imaging of neurovascular structures in the vertebral canal, but the success of surgical decompression and its correlation with clinical observations very seldom have been monitored by postoperation radiologic imaging. METHODS: In this study, 56 patients surgically treated for lumbar spinal stenosis were re-examined clinically by use of the Oswestry disability questionnaire. Their walking capacity was evaluated by the treadmill test. Severity of pain before and after the treadmill test was investigated using a visual analog scale. Patients' perception of improvement measured as the change in their condition during the preceding 5 years was elicited by a questionnaire. On the basis of the stenotic findings on magnetic resonance imaging, the patients were classified into no stenosis (NoSten, n = 15) and stenosis (Sten, n = 41) groups, and a summative degenerative scale also was constructed with the findings categorized as follows: disc degeneration, disc herniation, facet joint arthrosis, and degenerative spondylolisthesis. RESULTS: Whereas the patients' perception of improvement correlated very strongly with the Oswestry score and walking capacity, there was no statistical difference between the NoSten and Sten groups in the Oswestry score, walking capacity, perception of improvement, or severity of pain. The effect of the summative degenerative scale on the patients' walking capacity was 13 times greater than the effect of the minimum area of the dural sac. CONCLUSIONS: Patients' perception of improvement had a much stronger correlation with long-term surgical outcome than structural findings seen on postoperation magnetic resonance imaging. Moreover, degenerative findings had a greater effect on patients' walking capacity than stenotic findings.

Female↗
PubMed1999

Brain perfusion SPECT and MRI in foetal alcohol syndrome.

Six boys and five girls with a mean age of 8.6 (range 3 to 13) years with foetal alcohol syndrome (FAS) were studied by MRI and single photon emission computed tomography (SPECT) to find specific areas of vulnerability. Morphological anomalies shown in six of 11 patients by MRI were situated both cortically and subcortically: cortical atrophy (N = 2), dilated ventricle (N = 1), corpus callosum hypoplasia (N = 1), cerebellar atrophy (N = 2), one of the latter with Arnold-Chiari malformation (N = 1). Delayed myelination of the white matter was seen in two patients. Volumetric studies of the hippocampus showed morphological left-right asymmetry in five of eight patients. However, SPECT showed mild hypoperfusion of the left hemisphere in all 10 subjects. The negative left-right index was located especially in the left parietooccipital region, i.e. in the brain areas implicated in arithmetical and logical-grammatical functions, which are known to be affected in FAS. Normal left-right dominance was also lacking in the frontal area, i.e. the brain area affected in attention-deficit-hyperactivity disorder (ADHD). Detection of these abnormalities, although they are not unique to FAS, may be helpful in the diagnosis and any attempts at rehabilitation. Diverse morphological and functional abnormalities are more frequent than has usually been believed even in less impaired children with FAS.

Adolescent↗
PubMed1999

Incremental cost-effectiveness of double-reading mammograms.

BACKGROUND: Double reading is a widely used criterion standard in breast cancer screening despite a lack of evidence of the cost-effectiveness of the second reading. This study evaluates the incremental cost-effectiveness of such a strategy. DESIGN: Cost-effectiveness analysis: Nationwide population-based semi-annual screening program for women aged 50-59 in Finland. Participation rate was 91%. All mammograms (95,423) performed during 1990-1995 in three screening centers of the Finnish Cancer Society were read by two radiologists with gradings recorded. The effectiveness of the double reading was the difference in cancers detected in the double compared to that of the single reading. Incremental costs of the double reading for the health care and non-health care and the time costs were estimated. The main outcome measure was the incremental cost per additional cancer found as a result of the double-reading strategy. RESULTS: The total number of cancers detected with the double and single reading were 290 and 261, respectively. A significantly higher ratio of carcinoma in situ was the causative pathology in cancers detected only by the second reader. The cost per cancer detected with a single reading was US$ 18,340. The incremental cost of any additional cancer found was US$ 25,523, that is, a 39% higher cost per additional cancer found by double reading. CONCLUSIONS: The additional cost per cancer detected by double reading is not drastically higher than with single reading. However, the additional cost per life year saved may be much higher.

Breast Neoplasms↗
PubMed1999

Magnetic resonance imaging supplements ultrasonographic imaging of the posterior fossa, pharynx and neck in malformed fetuses.

OBJECTIVE: The objective of this study was to compare antepartum ultrasonography and magnetic resonance imaging (MRI) in the diagnosis and exclusion of malformations of the fetal neck, pharynx, skull base and posterior fossa in late pregnancy. MATERIALS AND METHODS: The study involved 26 women and 27 fetuses with ultrasonographically or clinically suspected abnormalities of the fetal neck, pharynx or central nervous system (CNS). Findings obtained by ultrasound were compared with those obtained by MRI (1.5 T) in the last trimester. RESULTS: In cases with CNS malformation (n = 19), MRI provided additional information on the anatomy of the foramen magnum and posterior fossa in nine cases (47%). When antepartum ultrasonography indicated malformation of the soft tissues of the neck or pharynx (n = 8), MRI provided additional information on diagnosis or exclusion of the abnormality in six cases (75%). The imaging capacity of the anatomy of the naso-, oro- and hypopharynx, trachea, esophagus and cervical skin outlines was better with MRI. CONCLUSIONS: MRI proved to be a valuable supplementary method to ultrasound in obtaining accurate information from the fetal neck, pharynx and posterior fossa, particularly when acoustic shadowing by bony structures or adjacent malformation impaired the quality of the ultrasonographic examination.

Abnormalities, Multiple↗
PubMed1999

Comparison of Aspergillus niger phytase and Trichoderma reesei phytase and acid phosphatase on phytate phosphorus availability in pigs fed on maize-soybean meal or barley-soybean meal diets.

The efficacy of Aspergillus niger (APhy) phytase, Trichoderma reesei (TPhy) phytase and acid phosphatase (TAcPh) preparations in improving the utilization of phytin-phosphorus in the maize-soybean meal (SBM) or barley-SBM (800:200 g kg-1) diets was studied in two separate digestibility and balance trials with ten growing pigs using 5 x 5 Latin square designs. The positive control diet contained a total phosphorus (P) of 6.5 g kg-1, while the negative control as well as the APhy, TPhy and TAcPh supplemented diets which did not contain additional inorganic-P, had a total P of 4.1 g kg-1. The APhy and TPhy supplements provided phytase activity of 1000 PU g-1 together with AcPh of 8000 HFU g-1. TAcPh at a level of 8000 HFU g-1 was the only addition to one diet. The intrinsic phytase activity of barley was 355 PU g-1 while maize and soybean meal showed no phytase activity. Phytase supplements of the APhy and TPhy sources increased ash digestibility in both diets but had only a minor effect on nitrogen utilization. The addition of phytase improved absorption of P by 21%-units in barley-SBM diet and 29%-units in maize-SBM diet, without any difference between the two phytase sources. The retained P in diets with phytase was higher than in diets without phytase, 4.4 (APhy), 4.5 (TPhy) vs. 2.9 g d-1 in barley-SBM-diets and 3.7 (APhy), 4.0 (TPhy) vs. 1.8 g d-1 in maize-SBM-diets. No difference was found between the two sources of phytase. TAcPh without additional phytase did not show any effect on P absorption or retention. Ca absorption and retention were improved due to the phytase treatments. Supplementing pig diets with either APhy or TPhy sources seems to be equally effective in enhancing the availability of phytate-P. Consequently, these supplements can reduce the P-excretion of pigs by 32-40% as compared with the diet supplemented with inorganic-P.

6-Phytase↗
PubMed1999

Comparative MR analysis of the entorhinal cortex and hippocampus in diagnosing Alzheimer disease.

BACKGROUND AND PURPOSE: Our purpose was to use volumetric MR imaging to compare the extent of atrophy and discriminative ability of the volumes of two temporal lobe structures, the entorhinal cortex and the hippocampus, between patients with Alzheimer disease and control subjects. METHODS: The study group consisted of 30 patients with probable Alzheimer disease diagnosed according to the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria and 32 healthy control subjects. The MR volumes of the entorhinal cortex and the hippocampus were used for the discriminant function and receiver operator characteristic analysis as well as multivariate analysis of variance for repeated measures to compare their discriminative power. RESULTS: Compared with control subjects, patients with Alzheimer disease had significantly smaller volumes of the entorhinal cortex and the hippocampus on both sides. Both the receiver operator characteristic and the discriminant function analyses using both volumes classified control subjects and Alzheimer patients with a high degree of accuracy (approximately 90%). Significant group x region interaction favoring hippocampal volumetry was determined by multivariate analysis of variance. CONCLUSION: The volumetric measurements of both the entorhinal cortex and hippocampus have comparably high discriminative power in diagnosing Alzheimer disease. In clinical practice, hippocampal volumetry may be more feasible, because the method is easier to use and has less variability.

Aged↗
PubMed1998

Hippocampal atrophy is related to impaired memory, but not frontal functions in non-demented Parkinson's disease patients.

We investigated the neuropsychological correlates of hippocampal atrophy in Parkinson's disease (PD) patients. The memory impaired PD patients had smaller hippocampi than other PD patients. The performance of PD patients in spatial working memory and attentional set-shifting correlated with the severity of motor defect, and not with hippocampal atrophy. Our results suggests that failure of verbal/visual memory may be related to hippocampal atrophy in Parkinson's disease. On the contrast, the defect in spatial working memory and attentional set-shifting may be sensitive to dysfunction of 'fronto-striatal' systems in PD patients.

Aged↗
PubMed1998

Subclinical cerebral complications after coronary artery bypass grafting: prospective analysis with magnetic resonance imaging, quantitative electroencephalography, and neuropsychological assessment.

OBJECTIVE: To analyze the frequency and severity of subclinical cerebral complications associated with coronary artery bypass grafting (CABG). DESIGN: A prospective controlled study using preoperative and postoperative magnetic resonance imaging (MRI) of the brain, quantitative electroencephalography (QEEG), and detailed neuropsychological and neurologic examinations as potentially sensitive indicators of subclinical cerebral injury associated with CABG. SETTING: Multimodality evaluation in a tertiary care unit (Kuopio University Hospital, Kuopio, Finland). PATIENTS: Thirty-eight patients undergoing elective CABG and 20 control patients undergoing other major vascular surgery, mostly operations on the abdominal aorta. MAIN OUTCOME MEASURES: Coronary artery bypass grafting-associated cerebral complications assessed preoperatively and postoperatively by brain MRI, QEEG, detailed neurologic examination, and a neuropsychological test battery that evaluates cognitive functions in major areas known to be vulnerable to organic impairment (learning and memory, attention, flexible mental processing, and psychomotor speed). RESULTS: There were no major neurologic complications. A mild hemisyndrome developed in 1 patient who underwent CABG and in 1 control patient. Overall, there was no decline in mean cognitive performance 3 months after surgery. Electroencephalographic slowing of 0.5 Hz or more in at least 2 channels occurred in 11 patients who underwent CABG and in 1 control patient (P=.03). The postoperative brain MRI scan revealed new small ischemic lesions in 8 patients (21%) in the CABG group but in none of the control group (P=.03). These new cerebral MRI lesions did not explain deterioration in neuropsychological test performance or the QEEG slowing. CONCLUSIONS: Coronary artery bypass grafting causes more QEEG alterations and small ischemic cerebral lesions that are detectable by MRI than does other major vascular surgery. The effect is mainly subclinical, because no statistically significant deterioration in mean neuropsychological test performance was detected.

Aged↗
PubMed1998

Placenta accreta: imaging by gray-scale and contrast-enhanced color Doppler sonography and magnetic resonance imaging.

Antepartum diagnosis of placenta accreta on the scarred myometrium of the isthmus uteri after previous cesarean section was made in 2 pregnancies. Antepartum sonographic examination revealed abnormal bulging of placental tissue toward the bladder cavity and arcuate arteries within the bladder wall. Magnetic resonance imaging revealed the depth and extent of placental invasion into the myometrium of the isthmus and the bladder muscular layer. Low-resistance pulsatile intervillous flow was recorded within the placenta in 1 case. Both magnetic resonance imaging and contrast-enhanced color Doppler sonography were informative in the other of these cases, in which the patient was conservatively managed during pregnancy and after delivery.

Adult↗
PubMed1998

MRI does not change fetal cardiotocographic parameters.

The aim of this study was to determine whether magnetic resonance imaging (MRI) has any effect on fetal cardiotocographic (CTG) parameters or movement incidence. Sixteen mothers were examined during the last trimester at 28-39 weeks (mean 33 weeks; SD 4) of gestation due to a suspected fetal anomaly found in antenatal ultrasonography (US). MR imaging was performed using Siemens Magnetom Vision 1.5 T equipment with a 25 mT/m peak gradient amplitude. T2-weighted images were produced with HASTE and TRUE-FISP sequences and T1-weighted images with a 2D FLASH sequence. A four-element phase-array coil was used as the receiver. Before and after MRI-examination, a computerized analysis of the fetal heart rate (FHR) was produced. Basal FHR, short-term variation (STV) and fetal movements were calculated. The mean basal FHR was 136 beats/min (SD 11.6) before, and 133 beats/min (SD 8.9) after (P = 0.158). Short-term variation was in the normal range for both CTG-tracings: mean 9.7 ms (SD 2.7) and 8.8 ms (SD 2.8) (P = 0.196). The median for fetal movements before MRI was 48/h, and after MRI 24.5/h (P = 0.98). MRI at high field strength with powerful gradients did not affect fetal heart activity or movement incidence.

Cardiotocography↗