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Biomedical subjects

R Vanninen

Publications and source records attributed to R Vanninen.

At least 19 recordsLinked to original sources

Cerebroretinal microangiopathy with calcifications and cysts.

BACKGROUND: Extensive cerebral calcifications and leukoencephalopathy have been reported in two rare disorders Coats plus and leukoencephalopathy with calcifications and cysts. In the latter, a progressive formation of parenchymal brain cysts is a special feature, whereas Coats plus is characterized by intrauterine growth retardation, bilateral retinal telangiectasias and exudations (Coats disease), sparse hair, and dysplastic nails without cyst formation. METHODS: We identified 13 patients, including two pairs of siblings, with extensive cerebral calcifications and leukoencephalopathy. We reviewed clinical, ophthalmologic, radiologic and neuropathologic data of seven deceased patients and studied five patients prospectively. RESULTS: Eleven patients were small for gestational age; the other symptoms emerged from infancy to adolescence. All patients had neurologic symptoms including seizures, spasticity, dystonia, ataxia, and cognitive decline. Progressive intracerebral calcifications involved deep gray nuclei, brainstem, cerebral and cerebellar white matter, and dentate nuclei and were accompanied by diffuse white matter signal changes and, in five patients, cerebral cysts. Eleven patients had retinal telangiectasias or angiomas. Additional features were skeletal and hematologic abnormalities, intestinal bleeding, and poor growth. Neuropathologic examination showed extensive calcinosis and abnormal small vessels with thickened, hyalinized wall and reduced lumen. CONCLUSIONS: Our data suggest that Coats plus syndrome and leukoencephalopathy with calcifications and cysts belong to the same spectrum. The primary abnormality seems to be an obliterative cerebral angiopathy involving small vessels, leading to dystrophic calcifications via slow necrosis and finally to formation of cysts and secondary white matter abnormalities.

Adolescent↗

Subarachnoid hemorrhage is followed by temporomesial volume loss: MRI volumetric study.

OBJECTIVE: To assess whether subarachnoid hemorrhage (SAH) and its treatment is followed by volume loss in temporomesial structures. METHODS: One hundred fifty-five consecutive patients with aneurysmal SAH were randomly assigned to surgical or endovascular treatment. Volumetric MRI was performed in 77 SAH patients with good or moderate clinical outcome 1 year after hemorrhage. A comprehensive neuropsychological test battery was used to evaluate the cognitive performance of the subjects. Thirty healthy individuals were imaged as MRI controls. RESULTS: The normalized hippocampal (HC) volumes were 24.7/23.7 (right/left), and the amygdaloid (AM) volumes were 21.0/20.5 in the matched control population. In SAH patients, the corresponding volumes were smaller, HC 23.2/21.3 (p = 0.072/0.002) and AM 18.4/18.7 (p = 0.012/0.045). In addition, the AM ipsilateral to the ruptured aneurysm was smaller in patients who had undergone surgical treatment (15.7) vs endovascular treatment (20.3; p < 0.001). Treatment modality did not significantly affect the measured HC volumes. The hippocampal but not amygdaloid volumes correlated with the scores of several neuropsychological tests. CONCLUSION: Subarachnoid hemorrhage and its treatment may be followed by atrophy in temporomesial structures. A clear correlation was demonstrated between neuropsychological performance and reduced temporomesial volumes.

Atrophy↗

Learning curve for add-on stereotactic core needle breast biopsy.

PURPOSE: To evaluate the learning curve for an add-on 14 G stereotactic core needle biopsy (SCNB). MATERIAL AND METHODS: A total of 231 non-palpable breast lesions that had undergone add-on SCNB were evaluated in this prospective study. Five radiologists performed their first three biopsies under supervision. Subsequent, independently performed, biopsies were also evaluated. The samples were collected in three different containers: the first sample in container A, the second and third samples in container B, and subsequent samples in container C (available for four radiologists from the first biopsy on). Technically successful biopsies and false-negative rate in three container combinations (A, A+B, A+B+C) were reported as a function of operator experience. RESULTS: Technically unsuccessful biopsies occurred significantly more often in microcalcifications than in masses (14.9% versus 3.8%; P=0.04). For microcalcifications, the rate of successful biopsies was 75% (18/24) for the first 5 biopsies and 87.8% (79/90) for the subsequent biopsies (P=0.335); rates for the masses were 95.7% (22/23) and 96.3% (79/82) (P=1.0), respectively. A tendency was noted for the false-negative rate to be higher for the first five biopsies in three container combinations than in subsequent cases. CONCLUSION: Our results support the existence of a learning curve, especially in the biopsy of microcalcifications. More than three mentor-guided biopsies are needed.

Biopsy, Needle↗

Hippocampal damage in newly diagnosed focal epilepsy: a prospective MRI study.

OBJECTIVE: To examine the longitudinal appearance of hippocampal (HC) damage in a prospective follow-up study of patients with newly diagnosed epilepsy. METHODS: A total of 103 patients with newly diagnosed focal epilepsy were scanned with MRI before antiepileptic medication was started. Serial MRI studies were scheduled after 1, 2 to 3, and 5 years of treatment in the ongoing follow-up study. Volumes of the HC were measured from MRI scans according to the Cavalieri method of modern design stereology and compared at different time points together with clinical variables. RESULTS: No difference was observed in the mean HC volumes between controls and patients at baseline, after 1, 2 to 3, and 5 years of follow-up. Individual analysis showed that 8% of patients had HC damage at the time of the diagnosis and 13% of patients developed HC volume decrease during 2 to 3 years of follow-up. These patients had longer duration of seizure disorder and larger seizure number before the epilepsy was diagnosed and treatment started compared with patients who did not show HC damage. CONCLUSIONS: Hippocampal volume decreases occur in individual patients with newly diagnosed focal epilepsy during the first years of treatment. The data obtained suggest that hippocampal volumetry provides a surrogate marker of the epileptic process.

Adolescent↗

A voxel based morphometry study on mild cognitive impairment.

BACKGROUND: Mild cognitive impairment (MCI) is the most widely used concept in classifying cognitive impairment in the elderly who do not fulfil the criteria for dementia. MCI is considered to confer an increased risk of progressing to dementia and most often Alzheimer's disease (AD). Various approaches such as imaging of the brain have been applied to predict the conversion of MCI to dementia. A number of volumetric magnetic resonance imaging (MRI) studies have detected atrophy of the medial temporal lobe in subjects with MCI, but for the other cerebral regions the results have been inconsistent. OBJECTIVE: To study the pattern of brain atrophy in MCI. METHODS: Thirty two controls and 51 individuals with MCI deriving from population based cohorts were studied by MRI using voxel based morphometry. The threshold of t maps was set at p < 0.001. RESULTS: Individuals with MCI had significant unilateral atrophy in the medial temporal lobe on the right side. Less extensive atrophy was found elsewhere-for example, in the temporal lobe, left superior parietal lobule, left anterior cingulate gyrus, and bilaterally in the thalami. CONCLUSIONS: The MRI findings in MCI resemble those seen in early AD.

Aged↗

Preoperative clinical evaluation, outline of surgical technique and outcome in temporal lobe epilepsy.

Temporal lobe epilepsy (TLE) is the most common type of refractory epilepsy. The mechanisms of epileptogenesis and seizure semiology of the mesial and neocortical temporal lobe epilepsy are discussed. The evaluation and selection of patients for TLE surgery requires team work: the different clinical aspects of neuropsychological evaluation, magnetic resonance and functional imaging (positron emission tomography, single photon emission computed tomography and magnetoenephalography) are reviewed. In our programme of epilepsy surgery at Kuopio University Hospital, Finland, we have performed 230 temporal resections from 1988 until 2002. Preoperative diagnostic EEG-videotelemetry often required intracranial monitoring and it has proved to be safe and efficient. The indications and technique for tailored temporal lobe resection with amygdalohippocampectomy used in our institution, as well as the complications, are described. Our analysis of outcome after temporal lobe surgery included 140 consecutive adult patients between 1988 and 1999; one year after the operation in unilateral TLE the Engel I-II outcome was observed in 68% of the patients. Outcome of surgery improved significantly after introduction of the standardised MR imaging protocol from 1993; 74% of patients with unilateral TLE achieved Engel I-II outcome.

Electroencephalography↗

Heterogeneity of cerebral blood flow in symptomatic patients undergoing carotid endarterectomy.

There is still controversy concerning which patients with asymptomatic carotid stenosis or symptomatic moderate stenosis are likely to benefit from carotid endarterectomy. The surgical candidates for carotid endarterectomy should have a high risk for stroke, but a low risk for operative complications. Therefore, new effective patient selection strategies, including haemodynamic testing, schemes of risk stratification and pre-operative cardiac testing, are under investigation. To improve haemodynamic assessment of patients with carotid artery stenosis, we evaluated a novel global cerebral blood flow (CBF) heterogeneity index at rest and after acetazolamide injection in patients undergoing carotid endarterectomy. CBF heterogeneity index was measured in 15 patients by using basal and acetazolamide enhanced 99mTc-HMPAO SPET both before and 1 month after surgery. CBF heterogeneity index was calculated as the coefficient of variation of a total of 44 cerebral regions representing mainly both ipsi- and contralateral grey matter. A high linear correlation was observed between CBF heterogeneity index and ipsilateral carotid stenosis degree (r=0.74, P=0.003). Before surgery, CBF heterogeneity index increased significantly after acetazolamide injection when compared to the basal condition (from 7.0+/-1.5 to 8.3+/-1.7%, P=0.008). This response disappeared after carotid endarterectomy. When compared to pure asymmetry of CBF (ipsi/contralateral CBF ratio), the CBF heterogeneity index seemed to reflect, more sensitively, the haemodynamic effects of carotid endarterectomy. The CBF heterogeneity index after acetazolamide injection is a sensitive marker of the haemodynamic consequences of carotid artery stenosis and its operative treatment.

Acetazolamide↗

Reproducibility of scoring emphysema by HRCT.

PURPOSE: We evaluated the reproducibility of three visual scoring methods of emphysema and compared these methods with pulmonary function tests (VC, DLCO, FEV1 and FEV%) among farmer's lung patients and farmers. MATERIAL AND METHODS: Three radiologists examined high-resolution CT images of farmer's lung patients and their matched controls (n=70) for chronic interstitial lung diseases. Intraobserver reproducibility and interobserver variability were assessed for three methods: severity, Sanders' (extent) and Sakai. Pulmonary function tests as spirometry and diffusing capacity were measured. RESULTS: Intraobserver kappa-values for all three methods were good (0.51-0.74). Interobserver kappa varied from 0.35 to 0.72. The Sanders' and the severity methods correlated strongly with pulmonary function tests, especially DLCO and FEV1. CONCLUSION: The Sanders' method proved to be reliable in evaluating emphysema, in terms of good consistency of interpretation and good correlation with pulmonary function tests.

Aged↗

Diffusion and perfusion MR imaging in acute ischemic stroke: a comparison to SPECT.

Diffusion (DWI) and perfusion (PWI) magnetic resonance imaging are relatively new methods of clinical imaging that probably can detect infarcted (DWI) and hypoperfused but still salvageable tissue (PWI) in acute human stroke. Forty-six acute stroke patients were imaged within 24 h of ictus, on the second day and after a week. SPECT was also performed on 23 patients in the acute phase (first or second day). On the first day, mean volume of hypoperfused tissue was significantly greater (P<0.001) than the infarcted tissue. The initial hypoperfusion volume correlated significantly with the final infarct size (P<0.001). The initial perfusion-diffusion mismatch correlated significantly with the infarct growth (P< or =0.001). The hypoperfusion volumes measured from PWI and SPECT correlated significantly (P<0.001). In conclusion, combined DWI and PWI is a powerful tool in evaluating the hemodynamics of acute ischemic stroke and can predict the infarct growth during 1 week.

Aged↗

MR urography in evaluation of acute flank pain: T2-weighted sequences and gadolinium-enhanced three-dimensional FLASH compared with urography. Fast low-angle shot.

OBJECTIVE: The aim of this study was to compare the usefulness of breath-hold heavily T2-weighted sequences with gadolinium-enhanced three-dimensional fast low-angle shot (3D FLASH) MR urography in the evaluation of patients with acute flank pain. SUBJECTS AND METHODS: Forty consecutive patients with symptoms of acute flank pain underwent MR urography followed immediately by excretory urography. Heavily T2-weighted (combined thin-slice half-Fourier acquisition single-shot turbo spin-echo [HASTE] and thick-slab single-shot turbo spin-echo) and 3D FLASH sequences were evaluated separately and independently by two experienced radiologists for the presence, cause, level, and degree of obstruction. Interobserver agreement was calculated using the kappa statistic. Excretory urography and the final clinical diagnosis were used as reference. RESULTS: Twenty-six patients were found to have unilateral obstruction caused by ureteral stones. Both MR urography methods were excellent for detecting obstruction. In the detection of stones 3D FLASH was superior, with a sensitivity of 96.2% and 100% and specificity of 100% and 100% for observers A and B, respectively, compared with a sensitivity of 57.7% and 53.8% and a specificity of 100% and 100%, respectively, for T2-weighted sequences. The best degree of obstruction was seen with 3D FLASH, and the interobserver agreement was excellent for stone detection (kappa = 0.97). CONCLUSION: T2-weighted sequences alone are not sufficient for examining patients with acute flank pain. However, the combined use of both T2-weighted and 3D FLASH sequences will ensure better confidence in the evaluation of acute suspected renal colic. MR urography can replace conventional excretory urography when the latter is contraindicated or undesirable.

Acute Disease↗

Thymidine kinase gene therapy for human malignant glioma, using replication-deficient retroviruses or adenoviruses.

Herpes simplex virus thymidine kinase (HSV tk) gene therapy combined with ganciclovir (GCV) medication is a potential new method for the treatment of malignant glioma. We have used both retrovirus-packaging cells (PA317/tk) and adenoviruses (Adv/tk) for gene therapy for malignant glioma. Retrovirus-packaging cells were used for eight tumors in seven patients and adenoviruses were used for seven tumors in seven patients. As a control group, seven tumors in seven patients were transduced with lacZ marker gene 4-5 days before tumor resection. Safety and efficacy of the gene therapy were studied with clinical evaluation, blood and urine samples, MRI follow-up, and survival of the patients. Four patients with adenovirus injections had a significant increase in anti-adenovirus antibodies and two of them had a short-term fever reaction. Frequency of epileptic seizures increased in two patients. No other adverse events possibly related to gene therapy were detected. In the retrovirus group, all treated gliomas showed progression by MRI at the 3-month time point, whereas three of the seven patients treated with Adv/tk remained stable (p < 0.05). Mean survival times for retrovirus, adenovirus, and control groups were 7.4, 15.0, and 8. 3 months, respectively. The difference in the survival times between the adenovirus and retrovirus groups was significant (p < 0.012). It is concluded that HSV tk gene therapy is safe and well tolerated. On the basis of these results further trials are justified, especially with adenovirus vectors.

Adenoviridae↗

Antepartum findings in fetal protein C deficiency.

A pregnancy with fetal homozygous protein C deficiency was complicated in the third trimester by fetal ventriculomegaly, intraorbital thrombosis and placental infarcts, which could be imaged by combined use of ultrasonography and MRI.

Adult↗

Herpes simplex virus thymidine kinase gene therapy in experimental rat BT4C glioma model: effect of the percentage of thymidine kinase-positive glioma cells on treatment effect, survival time, and tissue reactions.

Herpes simplex virus thymidine kinase (HSV-tk) gene transfer and ganciclovir (GCV) administration have been suggested for the treatment of malignant gliomas. To understand tissue responses and possible ways to improve the treatment effect, we studied tumor growth, tissue reactions, and survival time after HSV-tk/GCV treatment in a syngeneic BT4C rat glioma model by mixing various ratios of stably transfected HSV-tk-expressing BT4C-tk glioma cells with wild-type BT4C glioma cells (percentage of BT4C-tk cells: 0%, 1%, 10%, 30%, 50%, and 100%), followed by injection into BDIX rat brains (n = 79). With the exception of some animals with end-stage tumors, very little astroglia or microglia reactivity was detected in the wild-type tumors as analyzed by immunocytochemistry using glial fibrillary acid protein (GFAP)-, vimentin-, human histocompatibility leukocyte antigen-DR-, OX-42-, and CD68-specific monoclonal antibodies. After 14 days of GCV treatment, tumors induced with > or = 10% BT4C-tk cells showed a significant reduction in tumor size (P < .05) and prolonged survival time (P < .01). Astrogliosis, as indicated by a strong GFAP and vimentin immunoreactivity, was seen in the tumor scar area. GFAP and vimentin reactivity was already present after the GCV treatment in tumors induced with 1% BT4C-tk cells. Much less human histocompatibility leukocyte antigen-DR-positive microglia was seen in the treated animals, indicating low microglia reactivity and immunoactivation against the tumor. However, GCV-treated tumors were positive for apoptosis, indicating that apoptosis is an important mechanism for cell death in the BT4C-tk glioma model. Our results suggest that > or = 10% transfection efficiency is required for a successful reduction in BT4C glioma tumor size with HSV-tk/GCV treatment in vivo. Tissue reactions after 14 days of GCV treatment are characterized by astrogliosis and apoptosis, whereas microglia response and immunoactivation of the brain cells appear to play a minor role. Stimulation of the microglia response by gene transfer or other means might improve the efficacy of the HSV-tk/GCV treatment in vivo.

Animals↗

Outcomes of early endovascular versus surgical treatment of ruptured cerebral aneurysms. A prospective randomized study.

BACKGROUND AND PURPOSE: This prospective study was conducted to compare the outcomes of surgical clipping and endovascular treatment in acute (<72 hours) aneurysmal subarachnoid hemorrhage (SAH). METHODS: One hundred nine consecutive patients were randomly assigned to either surgical (n=57) or endovascular (n=52) treatment. Clinical and neuropsychological outcome was assessed at 3 and 12 months after treatment; MRI of the brain was performed at 12 months. Follow-up angiography was scheduled after clipping and 3 and 12 months after endovascular treatment. RESULTS: One year postoperatively, 43/41 (surgical/endovascular) patients had good or moderate recovery, 5/4 had severe disability or were in a vegetative state, and 9/7 had died (NS) according to intention to treat. Patients with good clinical recovery did not differ in their neuropsychological test scores. Symptomatic vasospasm (OR 2.47; 95% CI 1.45 to 4.19; P<0.001), poorer Hunt and Hess grade (OR 2.50; 95% CI 1.31 to 4.75; P=0.005), need for permanent shunt (OR 8.90; 95% CI 1.80 to 44.15; P=0.008), and larger size of the aneurysm (OR 1. 22; 95% CI 1.02 to 1.45; P=0.032) independently predicted worsened clinical outcome regardless of the treatment modality. In MRI, superficial brain retraction deficits (P<0.001) and ischemic lesions in the territory of the ruptured aneurysm (P=0.025) were more frequent in the surgical group. Kaplan-Meier analysis (mean+/-SD follow-up 39+/-18 months) revealed equal survival in both treatment groups. No late rebleedings have occurred. CONCLUSIONS: One-year clinical and neuropsychological outcomes seem comparable after early surgical and endovascular treatment of ruptured intracranial aneurysms. The long-term efficacy of endovascular treatment in preventing rebleeding remains open.

Aneurysm, Ruptured↗

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↗

Low efficacy of gene therapy for rat BT4C malignant glioma using intra-tumoural transduction with thymidine kinase retrovirus packaging cell injections and ganciclovir treatment.

BACKGROUND: The purpose of this study was to test the use of Herpes Simplex virus thymidine kinase (HSVtk) retrovirus packaging cell injections in the treatment of malignant brain tumours. METHODS: Therapeutic effect and tissue responses were examined in vivo in a syngeneic BT4C rat glioma model after HSVtk-producing PA317 packaging cell injections and intraperitoneal ganciclovir (GCV) medication. MRI was used to visualise the tumours before and after the treatment. Immunohistochemical stainings were performed to study astroglia and microglia responses and apoptosis-mediated cell death. RESULTS: The results suggest that only a limited treatment effect can be achieved with HSVtk packaging cell injections with no prolonged survival rates. Histological examination showed a strong astroglia response but only a modest microglia response after the treatment. HSVtk and GCV-induced cell death was at least partially mediated by apoptosis. It is concluded that HSVtk packaging cell injections and GCV treatment do not lead to eradication of malignant cells in a syngeneic BT4C rat glioma model. The lack of efficacy is most likely due to low gene transfer efficiency and limited life span of the injected packaging cell inside the tumours. CONCLUSIONS: Improvements in gene transfer efficiency, and stimulation of immunoresponse against tumour cells might lead to a more effective therapeutic response in vivo.

Animals↗

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↗

Ruptured intracranial aneurysms: acute endovascular treatment with electrolytically detachable coils--a prospective randomized study.

PURPOSE: To compare the use of electrolytically detachable coils versus surgical ligation for the management of acutely ruptured intracranial aneurysm. MATERIALS AND METHODS: A prospective randomized study included 109 patients with acute (< 72 hours) subarachnoid hemorrhage caused by a ruptured aneurysm (Hunt and Hess grade I-II [n = 67], grade III [n = 26], or grade IV-V [n = 16]). All patients were suitable candidates for both endovascular and surgical treatment and were randomly assigned to undergo coil embolization (n = 52) or surgical ligation (n = 57). RESULTS: Significantly better primary angiographic results were achieved after surgery in patients with anterior cerebral artery aneurysm (n = 55, P = .005) and after endovascular treatment in those with posterior circulation aneurysm (n = 11, P = .045). No significant differences were seen in middle cerebral artery (n = 19) or internal carotid artery (n = 24) aneurysms. Early rebleeding occurred in one patient after incomplete coil embolization. The technique-related mortality rate was 4% in the surgical group and 2% in the endovascular group. Clinical outcome (Glasgow Outcome Scale score) at 3 months was not significantly different between treatment groups in terms of intended treatment modality. No late rebleedings had occurred at the time of this writing. CONCLUSION: In selected patients with a recently ruptured intracranial aneurysm, favorable results were achieved by using endovascular treatment. Subsequent acute or late open surgery was sometimes required. The clinical outcome at 3 months was comparable in the endovascular and surgical treatment groups.

Acute Disease↗