Eija Pääkkö

Slow vasomotor fluctuation in fMRI of anesthetized child brain.

Signal intensity changes in fMRI during rest caused by vasomotor fluctuations were investigated in this work. Resting‐state baseline fluctuations were evaluated in 12 children anesthetized with thiopental. Five subjects had fluctuations related to subvoxel motion. In seven subjects without significant motion, slow signal fluctuation at 0.025–0.041 Hz near one or more primary sensory cortices was observed. In each subject the amplitude and frequency of the fluctuations were stable. It is hypothesized that thiopental, which reduces blood pressure and flow in the cortex, alters the feedback in neurovascular coupling leading to an increase in the magnitude and a reduction in the frequency of these fluctuations. The use of anesthesia in fMRI may provide new insight into neural connectivity and the coupling of blood flow and neural metabolism. Magn Reson Med 44:373–378, 2000.

Post-traumatic findings of the spine after earlier vertebral fracture in young patients: clinical and MRI study.

STUDY DESIGN A study comparing magnetic resonance imaging findings of degenerative changes in intervertebral discs in young patients with previous wedge-shaped compression fracture and age-matched and sex-matched control subjects. OBJECTIVES To find out the role of fractures in disc degeneration and to assess the clinical outcome of the patients. SUMMARY OF BACKGROUND DATA Several experimental studies have postulated that trauma is one of the major reasons for disc degeneration. Wedge compression fractures in vertebrae of children have been considered insignificant, but this has not been verified in the literature. METHODS Fourteen patients 8.8 to 20.8 years of age (mean, 15.5 years) with a history of wedge-shaped vertebral compression fracture at least 1 year previously (mean, 3.8 years) and asymptomatic healthy control subjects were studied by thoracolumbar spine magnetic resonance imaging. The patients also underwent a clinical examination. RESULTS Eight (57%) of the 14 patients had disc degeneration, and seven of them had it at the trauma level. Of these 7 subjects, 6 also had endplate damage at this level. The association between endplate damage and adjacent intervertebral disc degeneration was significant (P < 0.01). Only 2 of the patients were symptomatic. In the control group, only 1 subject had disc degeneration with endplate changes and disc herniation. CONCLUSIONS The patients had more disc degeneration than did those in the control group. Endplate injury was strongly associated with disc degeneration. No correlation between previous vertebral fracture and back pain was seen in this study.

High Body Mass Index Increases the Risk for Osteonecrosis in Children With Acute Lymphoblastic Leukemia

PURPOSE The aim of the study was to determine the incidence of and clinical risk factors for radiographic osteonecrosis (ON) in children treated for acute lymphoblastic leukemia (ALL) using the Nordic ALL protocols. PATIENTS AND METHODS Ninety-seven consecutive patients with childhood ALL were studied prospectively by magnetic resonance imaging (MRI) of the lower extremities at the end of the treatment. RESULTS Twenty-three (24%) of the 97 patients had ON. Seven of the patients (30%) were symptomatic, and three patients (13%) required surgical interventions. Multiple logistic regression analysis showed that high body mass index (BMI; P = .04), female sex (P = .01), older age at diagnosis (P < .001), and higher cumulative dexamethasone dose (P = .03) were independent risk factors for radiographic ON. The cumulative prednisone dose did not differ significantly between the patients with and without ON. The incidence of radiographic ON decreased significantly, from 36% to 7%, when the duration of dexamethasone exposure during the delayed-intensification phase was shortened from 3 to 4 weeks to 2 weeks with a taper (P = .001). CONCLUSION ON as determined by MRI was found to be a common complication in children and adolescents after treatment with the Nordic ALL protocols. Revision of the ALL protocols by shortening the single exposure to dexamethasone has diminished the risk for ON remarkably. High BMI was identified as a new significant risk factor for ON.

Prebiopsy Multiparametric Magnetic Resonance Imaging for Prostate Cancer Diagnosis in Biopsy-naive Men with Suspected Prostate Cancer Based on Elevated Prostate-specific Antigen Values: Results from a Randomized Prospective Blinded Controlled Trial

BACKGROUND Multiparametric magnetic resonance imaging (MP-MRI) may improve the detection of clinically significant prostate cancer (PCa). OBJECTIVE To compare MP-MRI transrectal ultrasound (TRUS)-fusion targeted biopsy with routine TRUS-guided random biopsy for overall and clinically significant PCa detection among patients with suspected PCa based on prostate-specific antigen (PSA) values. DESIGN, SETTING, AND PARTICIPANTS This institutional review board-approved, single-center, prospective, randomized controlled trial (April 2011 to December 2014) included 130 biopsy-naive patients referred for prostate biopsy based on PSA values (PSA <20 ng/ml or free-to-total PSA ratio ≤0.15 and PSA <10 ng/ml). Patients were randomized 1:1 to the MP-MRI or control group. Patients in the MP-MRI group underwent prebiopsy MP-MRI followed by 10- to 12-core TRUS-guided random biopsy and cognitive MRI/TRUS fusion targeted biopsy. The control group underwent TRUS-guided random biopsy alone. INTERVENTION MP-MRI 3-T phased-array surface coil. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS The primary outcome was the number of patients with biopsy-proven PCa in the MP-MRI and control groups. Secondary outcome measures included the number of positive prostate biopsies and the proportion of clinically significant PCa in the MP-MRI and control groups. Between-group analyses were performed. RESULTS AND LIMITATIONS Overall, 53 and 60 patients were evaluable in the MP-MRI and control groups, respectively. The overall PCa detection rate and the clinically significant cancer detection rate were similar between the MP-MRI and control groups, respectively (64% [34 of 53] vs 57% [34 of 60]; 7.5% difference [95% confidence interval (CI), -10 to 25], p=0.5, and 55% [29 of 53] vs 45% [27 of 60]; 9.7% difference [95% CI, -8.5 to 27], p=0.8). The PCa detection rate was higher than assumed during the planning of this single-center trial. CONCLUSIONS MP-MRI/TRUS-fusion targeted biopsy did not improve PCa detection rate compared with TRUS-guided biopsy alone in patients with suspected PCa based on PSA values. PATIENT SUMMARY In this randomized clinical trial, additional prostate magnetic resonance imaging (MRI) before prostate biopsy appeared to offer similar diagnostic accuracy compared with routine transrectal ultrasound-guided random biopsy in the diagnosis of prostate cancer. Similar numbers of cancers were detected with and without MRI. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT01357512.

Severity of symptoms and signs in relation to magnetic resonance imaging findings among sciatic patients.

Study Design. A cross-sectional study in sciatic population. Objectives. To evaluate the separate roles of nerve root entrapment—based on magnetic resonance imaging—and other discogenic pain mechanisms on disability and physical signs among symptomatic sciatic patients. Summary of Background Data. Data symptoms of sciatica are generally understood to be generated by nerve root compression, but other pain mechanisms of sciatica have been suggested. Methods. The authors obtained magnetic resonance scans from 160 patients with unilateral sciatic pain. The patients reported the intensity of their back and leg pain and their back-specific disability. Clinical examination and magnetic resonance imaging (1.5 T) was performed on every patient. The degree of disc displacement, neural enhancement, and nerve root compression was evaluated from magnetic resonance scans. The correlations of symptoms and signs with magnetic resonance imaging findings were calculated. Results. The degree of disc displacement in magnetic resonance imaging did not correlate with any subjective symptoms, nor did nerve root enhancement or nerve compression. Magnetic resonance imaging classification was associated, however, with straight leg raising restriction. In regression analysis, straight leg raising restriction was best explained with a simple classification of nonherniations versus herniations. Conclusions. The results suggest that a discogenic pain mechanism other than the nerve root entrapment generates the subjective symptoms among sciatic patients. The findings of this study thus indicate that magnetic resonance imaging is unable to distinguish sciatic patients in terms of the severity of their symptoms.

Radiation-induced meningiomas: A shadow in the success story of childhood leukemia

While the prognosis of acute childhood leukemia has improved, long-term survivors are increasingly experiencing late effects of the treatment. Cranially irradiated survivors are predisposed to the development of CNS tumors. Our aim was to describe the incidence of secondary brain tumors and to define the significance of treatment-related risk factors and host characteristics in a cohort of childhood leukemia survivors. Our cohort consisted of 60 consecutive cranially irradiated adult survivors of childhood leukemia treated in Oulu University Hospital (Oulu, Finland); MRI of the brain was performed on 49. The sites of the tumors, their histology, and details of the leukemia treatment were determined. Of the 49 patients, 11 (22%) 1-8 years of age at the time of diagnosis developed meningioma later in life, while no other brain tumors were seen. In this cohort, the development of meningioma seemed to show undisputable linkage with long latency periods (mean, 25 years; range, 14-34 years) and an increasing incidence 20 years after the treatment (47%). Three patients had multiple meningiomas, two had recurrent disease, and one had an atypical meningioma. Age at the time of irradiation, gender, or cumulative doses of chemotherapeutic agents showed no significant association with the development of meningiomas. The high incidence of meningiomas in this study was associated with long follow-up periods. Although the cohort is small, it seems probable that the increasing incidence of meningioma will shadow the future of cranially irradiated leukemia survivors. Systematic brain imaging after the treatment is therefore justifiable.

Magnetic resonance imaging findings in relation to the COL9A2 tryptophan allele among patients with sciatica.

Study Design. The phenotype of patients with sciatica who have the Trp2 allele is characterized cross-sectionally. Objective. To determine whether it is possible to differentiate patients with the Trp2 allele clinically or by magnetic resonance imaging. Summary of Background Data. Several studies have indicated a positive family history for intervertebral disc disease. Previously, a dominantly inherited defect was identified in the COL9A2 gene that changed a codon for glutamine to that for tryptophan in the &agr;2 chain of collagen IX (Trp2 allele). This change may render intervertebral discs more fragile. Methods. Clinical findings, clinical symptoms, and magnetic resonance imaging (1.5-T) findings from 159 patients with sciatica were evaluated according to the presence of the Trp2 allele. Additionally, the magnetic resonance imaging scans of 22 family members from three families were evaluated. These scans were analyzed intervertebral disc and endplate degeneration, Schmorl’s nodes, transverse tears (hyperintensity in the region of Sharpey’s fibers), high-intensity zone lesions (bright spots in the dorsal anulus), and radial tears (hyperintense linear area from the nucleus to the outer part of the anulus on T2 sequences). Results. Six patients with sciatica and 11 family members had the Trp2 allele. No homozygotes were found. Clinical symptoms of patients with and those without the Trp2 allele were similar. Patients with sciatica who had the Trp2 allele were significantly more flexible (P < 0.05), according to the modified Schober measure. The disc and endplate degeneration in 6 patients with the Trp2 allele and their 18 controls (matched for age, occupation, gender) without the allele did not differ significantly, whereas family members with the Trp2 allele had a greater degree of disc and endplate degeneration at L5–S1. The overall prevalence of endplate degeneration was high in this study. The prevalences of dorsal transverse tears, high-intensity zone lesions, and Schmorl’s nodes did not differ among patients with sciatica or family members according to the presence of the Trp2 allele. There was, however, a trend for increased prevalence of radial tears in nonherniated discs among the Trp2 allele–positive subjects (3 of 6 patients with sciatica and 3 of 11 family members), as compared with the Trp2-negatives subjects (none of 18 “matched” patients or 11 family members). Conclusion. The patients with the Trp2 allele were more flexible, and more often tended to have a radial tear in a nonherniated disc than their control counterparts.

Cardiovascular autonomic dysfunction correlates with brain MRI lesion load in MS

OBJECTIVE The aim of the present study was to investigate the cardiovascular autonomic control in clinically definite multiple sclerosis (MS) patients with a standardised battery of cardiovascular tests and to correlate these findings with the brain magnetic resonance imaging (MRI) lesion load. METHODS Fifty-one patients with MS and 50 healthy controls were studied. Brain MRI was performed in all patients showing typical MS lesions. The cardiovascular tests were carried out using a standardised battery. RESULTS Heart rate (HR) responses to deep breathing (P < 0.05) and tilt table testing (P < 0.001) were significantly decreased in MS patients when compared to those of the controls. Blood pressure (BP) responses in the tilt table test were also impaired in MS patients (diastolic P < 0.001, systolic P < 0.05). Of the different brain areas investigated the total volume of the midbrain MRI lesions (P < 0.05) was the one most clearly associated with the impaired BP responses. CONCLUSIONS MS results in both reduced HR variation and decreased BP reactions indicating disturbed cardiovascular regulation. In particular, the midbrain lesions found in MS are associated with cardiovascular dysfunction.

Validity of upper airway assessment in children A clinical, cephalometric, and MRI study

OBJECTIVE To test the hypothesis that the capability of two-dimensional lateral cephalogram in recognizing pharyngeal obstruction is poor compared with the capability of three-dimensional magnetic resonance imaging (MRI) and clinical observation of tonsillar size. MATERIALS AND METHODS The study participants were 36 prepubertal children (19 male, 17 female; mean age 7.3 ± 1.43 years, range 4.8-9.8 years) with sleep-disordered breathing diagnosed by nocturnal polygraphy. Pharyngeal airway was imaged with a low-field open-configuration MRI scanner. Tonsillar size was clinically determined and lateral skull radiographs were taken and measured. Pearson correlation coefficients were calculated between the clinical, cephalometric, and MRI variables. RESULTS Nasopharyngeal and retropalatal cephalometric variables had a significant positive correlation with the MRI findings. Both techniques showed the narrowest measurement to be located in the retropalatal region. Clinical assessment of tonsillar size correlated inversely with MRI findings such as minimal retropalatal cross-sectional airway area (P  =  .000), minimal retroglossal cross-sectional airway area (P  =  .015), and intertonsillar airway width (P  =  .000). Cephalometric soft palate and tonsillar area correlated with clinical tonsillar size (P  =  .001). CONCLUSIONS The hypothesis is rejected. The findings confirm that the lateral cephalogram is a valid method for measuring dimensions of the nasopharyngeal and retropalatal region. When evaluating oropharyngeal size, clinical assessment of tonsillar size is a relatively reliable method.

Central nervous system-related symptoms and findings are common in acute Puumala hantavirus infection.

Abstract Background. Puumala hantavirus (PUUV) causes a hemorrhagic fever with renal syndrome (HFRS) also called nephropathia epidemica (NE). Recent case reports and retrospective studies suggest that NE may damage the pituitary gland. Based on these observations, our goal was to explore the nature of this complication prospectively. Methods. A total of 58 hospitalized patients with acute NE volunteered to participate. Central nervous system (CNS) symptoms were recorded, cerebrospinal fluid (CSF) samples were collected, human leukocyte antigen (HLA) haplotype was analyzed, brain magnetic resonance imaging (MRI) was acquired, and electroencephalography (EEG) was recorded. Patients with abnormal pituitary MRI finding were examined by an endocrinologist. Results. Most patients experienced CNS symptoms, and half of the CSF samples were positive for PUUV IgM, elevated protein level, or leukocyte count. CSF of patients negative for DR15(2)-DQ6 haplotype was less frequently affected. MRI revealed pituitary hemorrhage in two patients; these two patients suffered sudden loss of vision associated with headache, and they both developed hypopituitarism. Only one patient required long-term hormonal replacement therapy. Conclusion. CNS-related symptoms and inflammation in the CSF are common in acute NE. Genetic properties of the host may predispose to CNS involvement. It does seem that pituitary injury and subsequent hormonal insufficiency may complicate the recovery.