Mathematical abilities in dyslexic children: a diffusion tensor imaging study.

Dyslexia is characterized by a deficit in language processing which mainly affects word decoding and spelling skills. In addition, children with dyslexia also show problems in mathematics. However, for the latter, the underlying structural correlates have not been investigated. Sixteen children with dyslexia (mean age 9.8 years [0.39]) and 24 typically developing children (mean age 9.9 years [0.29]) group matched for age, gender, IQ, and handedness underwent 3 T MR diffusion tensor imaging as well as cognitive testing. Tract-Based Spatial Statistics were performed to correlate behavioral data with diffusion data. Children with dyslexia performed worse than controls in standardized verbal number tasks, such as arithmetic efficiency tests (addition, subtraction, multiplication, division). In contrast, the two groups did not differ in the nonverbal number line task. Arithmetic efficiency, representing the total score of the four arithmetic tasks, multiplication, and division, correlated with diffusion measures in widespread areas of the white matter, including bilateral superior and inferior longitudinal fasciculi in children with dyslexia compared to controls. Children with dyslexia demonstrated lower performance in verbal number tasks but performed similarly to controls in a nonverbal number task. Further, an association between verbal arithmetic efficiency and diffusion measures was demonstrated in widespread areas of the white matter suggesting compensatory mechanisms in children with dyslexia compared to controls. Taken together, poor fact retrieval in children with dyslexia is likely a consequence of deficits in the language system, which not only affects literacy skills but also impacts on arithmetic skills.

Cortical thinning in former professional soccer players.

Soccer is the most popular sport in the world. Soccer players are at high risk for repetitive subconcussive head impact when heading the ball. Whether this leads to long-term alterations of the brain's structure associated with cognitive decline remains unknown. The aim of this study was to evaluate cortical thickness in former professional soccer players using high-resolution structural MR imaging. Fifteen former male professional soccer players (mean age 49.3 [SD 5.1] years) underwent high-resolution structural 3 T MR imaging, as well as cognitive testing. Fifteen male, age-matched former professional non-contact sport athletes (mean age 49.6 [SD 6.4] years) served as controls. Group analyses of cortical thickness were performed using voxel-based statistics. Soccer players demonstrated greater cortical thinning with increasing age compared to controls in the right inferolateral-parietal, temporal, and occipital cortex. Cortical thinning was associated with lower cognitive performance as well as with estimated exposure to repetitive subconcussive head impact. Neurocognitive evaluation revealed decreased memory performance in the soccer players compared to controls. The association of cortical thinning and decreased cognitive performance, as well as exposure to repetitive subconcussive head impact, further supports the hypothesis that repetitive subconcussive head impact may play a role in early cognitive decline in soccer players. Future studies are needed to elucidate the time course of changes in cortical thickness as well as their association with impaired cognitive function and possible underlying neurodegenerative process.

Altered Neurochemistry in Former Professional Soccer Players without a History of Concussion.

Soccer is played by more than 250 million people worldwide. Repeatedly heading the ball may place soccer players at high risk for repetitive subconcussive head impacts (RSHI). This study evaluates the long-term effects of RSHI on neurochemistry in athletes without a history of clinically diagnosed concussion, but with a high exposure to RSHI. Eleven former professional soccer players (mean age 52.0±6.8 years) and a comparison cohort of 14 age- and gender-matched, former non-contact sport athletes (mean age 46.9±7.9 years) underwent 3T magnetic resonance spectroscopy (MRS) and neurocognitive evaluation. In the soccer players a significant increase was observed in both choline (Cho), a membrane marker, and myo-inositol (ml), a marker of glial activation, compared with control athletes. Additionally, ml and glutathione (GSH) were significantly correlated with lifetime estimate of RSHI within the soccer group. There was no significant difference in neurocognitive tests between groups. Results of this study suggest an association between RSHI in soccer players and MRS markers of neuroinflammation, suggesting that even subconcussive head impacts affect the neurochemistry of the brain and may precede neurocognitive changes. Future studies will need to determine the role of neuroinflammation in RSHI and the effect on neurocognitive function.

MRI evidence for preserved regulation of intracranial pressure in patients with cerebral arteriovenous malformations.

PURPOSE: The purpose of this study was to investigate intracranial pressure and associated hemo- and hydrodynamic parameters in patients with cerebral arteriovenous malformations AVMs. METHODS: Thirty consecutive patients with arteriovenous malformations (median age 38.7 years, 27/30 previously treated with radiosurgery) and 30 age- and gender-matched healthy controls were investigated on a 3.0T MR scanner. Nidus volume was quantified on dynamic MR angiography. Total arterial cerebral blood flow (tCBF), venous outflow as well as aqueductal and craniospinal stroke volumes were obtained using velocity-encoded cine-phase contrast MRI. Intracranial volume change during the cardiac cycle was calculated and intracranial pressure (ICP) was derived from systolic intracranial volume change (ICVC) and pulse pressure gradient. RESULTS: TCBF was significantly higher in AVM patients as compared to healthy controls (median 799 vs. 692 mL/min, p=0.007). There was a trend for venous flow to be increased in both the ipsilateral internal jugular vein (IJV, 282 vs. 225 mL/min, p=0.16), and in the contralateral IJV (322 vs. 285 mL/min, p=0.09), but not in secondary veins. There was no significant difference in median ICP between AVM patients and control subjects (6.9 vs. 8.6 mmHg, p=0.30) and ICP did not correlate with nidus volume in AVM patients (ρ=-0.06, p=0.74). There was a significant positive correlation between tCBF and craniospinal CSF stroke volume (ρ=0.69, p=0.02). CONCLUSIONS: The elevated cerebral blood flow in patients with AVMs is drained through an increased flow in IJVs but not secondary veins. ICP is maintained within ranges of normal and does not correlate with nidus volume.

Magnetic resonance-based estimation of intracranial pressure correlates with ventriculoperitoneal shunt valve opening pressure setting in children with hydrocephalus.

OBJECTIVES: The aim of this study was to investigate the relationship between the pressure setting of the ventriculoperitoneal (VP) shunt valve and a magnetic resonance (MR)-based estimate of intracranial pressure (ICP) in children with shunt-treated hydrocephalus without clinical signs of shunt malfunction. MATERIALS AND METHODS: Institutional review board approval was obtained before the study, and all subjects and/or their legal guardians provided written informed consent. In this prospective study, 15 consecutive patients (median age, 8.25 years; range, 2.2-18.4 years; 6 girls and 9 boys) with shunt-treated hydrocephalus without signs of shunt malfunction were examined with retrospectively gated phase contrast sequences to quantify arterial inflow, venous outflow, and cerebrospinal fluid (CSF) flow to and from the cranial vault. The ratio of the maximal intracranial volume change and the pulse pressure gradient change was used to derive MR-ICP. Spearman ρ was used to test for the association of setting of the shunt valve opening pressure and MR-ICP. RESULTS: Shunt valve opening pressure settings and MR-ICP were positively correlated (Spearman ρ = 0.64, P < 0.01). Median MR-ICP was 8.67 mm Hg (interquartile range [IQR], 1.59 mm Hg) and median setting of the VP-shunt valve was 6.62 mm Hg (IQR, 1.47 mm Hg). The median MR-ICP was 1.9 mm Hg (IQR, 0.73 mm Hg) higher than the setting of the shunt valve. CONCLUSION: There is a positive correlation between MR-ICP and VP shunt valve opening pressure setting. The systematically higher assessment of MR-ICP is most likely a result of outflow resistance within the shunt tubing system and well within the known fluctuation rates of VP shunt systems.

Inter- and intra-rater reliability of blood and cerebrospinal fluid flow quantification by phase-contrast MRI.

PURPOSE: To evaluate the intra- and inter-rater reliability of the quantification of blood and CSF flow rates by phase contrast MRI. MATERIALS AND METHODS: Blood and CSF flows in the upper cervical region were imaged with velocity-encoded cine-phase contrast using 3T scanners from different manufacturers at two centers. Data of 6 subjects scanned in center A and of 5 subjects in center B were analyzed by six readers at two levels of training. Each data set was analyzed three times in a randomized order for a total of 33 data sets. Intra-class correlation coefficients (ICC) were calculated for the primary measurements of areas and flow rates through the main cervical arteries, veins and the CSF space, and for secondary parameters derived from the individual flow rates. RESULTS: ICC ranged from 0.80 to 0.96 for the lumen area and from 0.97 to 0.99 for the volumetric flow rate. The ICC for the derived secondary measures ranged from 0.85 to 0.99. Differences due to operator level of training were not statistically significant. CONCLUSION: High intra- and inter-rater reliability of volumetric flow rate measurements is currently achievable across manufacturers and users' skill levels with a pulsatility based automated lumen segmentation.

Non-specific alterations of craniocervical venous drainage in multiple sclerosis revealed by cardiac-gated phase-contrast MRI.

OBJECTIVE: There is an on-going controversy about venous drainage abnormalities in multiple sclerosis (MS). We applied cardiac-gated phase-contrast and venographic magnetic resonance (MR) techniques to compare venous drainage patterns in patients with MS, healthy controls, and subjects with migraine. METHODS: A total of 27 patients with MS (21 female, age 12-59 years, mean disease duration 8.4 ± 8.5 years) and 27 age- and gender-matched healthy controls (21 female, age 12-60 years) were investigated with velocity-encoded cine-phase contrast MR sequences and a 2D time-of-flight MR venography of the cervicocranial region on a 3-T MRI. The data were compared with 26 patients with chronic migraine headaches (19 female, age 17-62 years), previously investigated with the same protocol. The degree of primary and secondary venous outflow in relation to the total cerebral blood flow (tCBF) was compared both quantitatively and qualitatively. Statistical analyses were performed using linear regression models. RESULTS: Secondary venous outflow was significantly increased in patients with MS compared with healthy controls, both qualitatively (p < 0.001) and quantitatively (p < 0.013). The observed changes were independent of age and disease duration. Very similar alterations of venous drainage were detectable with the same approach in patients with migraine, without significant differences between MS and migraine patients (p = 0.65). CONCLUSION: Our MRI-based study suggests that patients with MS have alterations of cerebral venous drainage similar to subjects with chronic migraine. These non-disease-specific changes seem to a secondary phenomenon rather than being of primary pathogenic importance.

Whole-body MR imaging in psoriatic arthritis: additional value for therapeutic decision making.

PURPOSE: In psoriatic arthritis (PsA) multiple locations may show inflammatory changes not always readily accessible to clinical exam. Often, clinical exam is inconclusive and the decision to initiate or adapt therapy is difficult. Whole body (WB)-MRI may help in this situation by providing a comprehensive overview of affected areas/joints. The purpose of this study was to make a proof of concept whether WB-MRI in psoriatic arthritis is feasible and can provide additional information compared to clinical examination alone with regard to therapeutic decision making in patients with PsA and inconclusive clinical situation. MATERIALS AND METHODS: 30 patients with PsA and diffuse musculoskeletal pain were examined. A WB-MRI protocol was implemented on a 1.5 Tesla scanner using coronal and sagittal STIR- (TR: 5800, TE: 54, matrix 384(2) pixels, FOV 400 mm) and pre- and steady-state-post-Gadolinium-VIBE sequences (TR: 9.82, TE: 4.53, matrix 384×307 pixels, FOV: 400 mm). MRI was evaluated for image quality and inflammatory findings by two readers in consensus and compared to clinical exam. RESULTS: The WB-MR-exam was well tolerated by all patients. Image quality was rated good to excellent in 26 of 30 patients (86.6%). WB-MRI detected significantly (p<0.001) more areas of synovitis/enthesitis than clinical exam except for the hands and feet. MRI was able to detect unknown destructive bony changes in 10 patients (53%). In 22 patients (73.3%) the therapy regimen was modified, in 18 patients (62%) TNF-alpha-inhibitors were started. CONCLUSION: Whole-body MRI (WB-MRI) may be integrated in the diagnostic work-up of patients with psoriatic arthropathy facilitating individual adaptation of therapeutic strategy.

Assessment of the internal craniocervical ligaments with a new magnetic resonance imaging sequence: three-dimensional turbo spin echo with variable flip-angle distribution (SPACE).

PURPOSE: Lesions close to the internal craniocervical ligaments are a common problem in patients with whiplash injuries. The aim of this study was to evaluate the morphology and visibility of these ligamentous structures with a new isotropic three-dimensional (3D) turbo-spin-echo (TSE) technique. MATERIALS AND METHODS: MR (MR) images of the cervical spine of 52 healthy subjects (27 women and 25 men; mean age=29 years; age range=18-40 years) were taken with a T2-weighted 3D TSE sequence with variable flip-angle distribution [SPACE (Sampling Perfection with Application optimized Contrasts using different flip-angle Evolution)] at 1.5 T (Magnetom Avanto, Siemens Erlangen, Germany). Two experienced musculoskeletal radiologists read the images independently on a 3D imaging and postprocessing workstation. The visibility and morphology of the alar ligaments were evaluated on a five-point scale, and inter-reader correlation was assessed with kappa statistics. RESULTS: Both alar ligaments were detected in all subjects. Twenty-eight (53.8%) of the alar ligaments could not be seen within one slice of the standard coronal imaging plane but could adequately be visualized in an oblique reconstruction adapted to the orientation of the ligaments on the axial slices. Inter-reader correlation for visibility on MR imaging (MRI) of the internal craniocervical ligaments was high (left+right side, kappa=0.95). Most (94%) alar ligaments presented symmetrically. In the axial plane, 60% were oriented neutral and 40% had a backward orientation. In the coronal plane, 67% were oriented caudocranially and 33% were oriented horizontally. The shape of the ligaments was parallel in half and was V-shaped in the other half. The alar ligaments had homogeneous low-signal intensity in 56% and heterogeneous low-signal intensity in 44%. The apical ligament of the dens was seen (excellent-good-moderate) in 61% (reader 1) and 52% (reader 2). The tectorial membranes and the transverse ligament of the atlas were shown (excellent-good) in all subjects. CONCLUSIONS: MRI with acquisition of an isotropic SPACE technique allows high-resolution imaging of the craniocervical ligaments in all orientations. Reconstruction of the image data in the variable orientation of the alar ligaments allowed for excellent depiction within one slice such that partial volume artifacts that hamper image analysis can be eliminated.