The effect of interventions on appropriate use of lumbar spine radiograph and CT examinations in young adults and children: a three-year follow-up.

BACKGROUND: According to international guidelines, radiological examinations of the lumbar spine are of limited value and do not improve clinical outcome unless there are clinical red flags present suggesting serious pathology. Nevertheless, the utilization of lumbar spine imaging remains high. PURPOSE: To follow up the effects of active referral guideline implementation and education on the number and appropriateness of lumbar spine radiographs and computed tomography (CT) examinations in young patients and to evaluate whether the appropriate radiographs have more significant findings. MATERIAL AND METHODS: Referral guidelines for spine examinations and info pocket cards on radiation protection were distributed to referring practitioners. Educational lectures were provided annually. The number of lumbar spine radiographs and CT examinations on patients aged <35 years was analyzed before and three years after the interventions. Appropriateness and findings of 313 radiographs and appropriateness of 117 CT scans of the lumbar spine were assessed. RESULTS: The number of lumbar spine radiographs and CT scans decreased significantly after the interventions and the level remained unchanged during the follow-up (-33% and -72%, respectively, P < 0.001). Appropriateness improved significantly in radiographs from 2005 to 2009 (65% vs. 85%) and in CT scans already from 2005 to 2007 (23% vs. 63%). Radiographs that were in accordance with the guidelines had more significant findings compared to radiographs that were not; in young adults, this was 56% versus 21% (P < 0.001). CONCLUSION: A combination of interventions can achieve a sustained reduction in the number of lumbar spine examinations and improve appropriateness. Inappropriate lumbar spine radiographs do not seem to contain significant findings that would affect patient care.

Parents' received and expected information about their child's radiation exposure during radiographic examinations.

BACKGROUND: Despite regulations, insufficient information is provided to adult patients prior to their radiologic examinations. Information regarding paediatric patients has not been systematically studied. OBJECTIVE: To survey parents' experience and wishes for information in connection with their child's radiographic examination. MATERIALS AND METHODS: We provided a questionnaire to consenting parents of children younger than 12 years old at a university hospital. The questionnaire asked parents about the information obtained from the referrer prior to the radiograph, the chance to discuss with the referrer and their wishes regarding future information. Forty-one parents responded to the survey. Twenty-five children were referred for radiography of extremities, the others for dental, body and skull examinations. RESULTS: Altogether 34/41 (83%, 95% confidence interval [CI] 69-91%) parents said they received adequate information on the purpose of the examination, 8/35 (23%, 95% CI 12-39%) on other options and 3/41 (7%, 95% CI 3-19%) on radiation dose. Ten of 41 parents (24%, 95% CI 12-40%) said they were aware of radiation exposure. The number of previous radiology examinations was not sufficiently discussed. The communication was scored as mean 6.5 (95% CI 5.8-7.1) on a scale from 4 (poor) to 10 (excellent). Thirty-eight of 40 (95%, 95% CI 84-99%) of parents expected information on the purpose, 35/40 (88%, 95% CI 74-95%) on radiation dose and 31/40 (78%, 95% CI 63-88%) on other options. Symbols of radiation and corresponding period of natural background radiation are preferred to convey the dose. A referrer is the preferred source of information. CONCLUSION: Parents did not feel adequately informed prior to their child's radiographic examination. Parents expect more information about the purpose, dose and alternative tests.

Fluctuations of the EEG-fMRI correlation reflect intrinsic strength of functional connectivity in default mode network.

Both functional magnetic resonance imaging (fMRI) and electrophysiological recordings have revealed that resting-state functional connectivity is temporally variable in human brain. Combined full-band electroencephalography-fMRI (fbEEG-fMRI) studies have shown that infraslow (<.1 Hz) fluctuations in EEG scalp potential are correlated with the blood-oxygen-level-dependent (BOLD) fMRI signals and that also this correlation appears variable over time. Here, we used simultaneous fbEEG-fMRI to test the hypothesis that correlation dynamics between BOLD and fbEEG signals could be explained by fluctuations in the activation properties of resting-state networks (RSNs) such as the extent or strength of their activation. We used ultrafast magnetic resonance encephalography (MREG) fMRI to enable temporally accurate and statistically robust short-time-window comparisons of infra-slow fbEEG and BOLD signals. We found that the temporal fluctuations in the fbEEG-BOLD correlation were dependent on RSN connectivity strength, but not on the mean signal level or magnitude of RSN activation or motion during scanning. Moreover, the EEG-fMRI correlations were strongest when the intrinsic RSN connectivity was strong and close to the pial surface. Conversely, weak fbEEG-BOLD correlations were attributable to periods of less coherent or spatially more scattered intrinsic RSN connectivity, or RSN activation in deeper cerebral structures. The results thus show that the on-average low correlations between infra-slow EEG and BOLD signals are, in fact, governed by the momentary coherence and depth of the underlying RSN activation, and may reach systematically high values with appropriate source activities. These findings further consolidate the notion of slow scalp potentials being directly coupled to hemodynamic fluctuations.

Combined spatiotemporal ICA (stICA) for continuous and dynamic lag structure analysis of MREG data.

This study investigated lag structure in the resting-state fMRI by applying a novel independent component (ICA) method to magnetic resonance encephalography (MREG) data. Briefly, the spatial ICA (sICA) was used for defining the frontal and back nodes of the default mode network (DMN), and the temporal ICA (tICA), which is enabled by the high temporal resolution of MREG (TR=100ms), was used to separate both neuronal and physiological components of these two spatial map regions. Subsequently, lag structure was investigated between the frontal (DMNvmpf) and posterior (DMNpcc) DMN nodes using both conventional method with all-time points and a sliding-window approach. A rigorous noise exclusion criterion was applied for tICs to remove physiological pulsations, motion and system artefacts. All the de-noised tICs were used to calculate the null-distributions both for expected lag variability over time and over subjects. Lag analysis was done for the three highest correlating denoised tICA pairs. Mean time lag of 0.6s (± 0.5 std) and mean absolute correlation of 0.69 (± 0.08) between the highest correlating tICA pairs of DMN nodes was observed throughout the whole analyzed period. In dynamic 2min window analysis, there was large variability over subjects as ranging between 1-10sec. Directionality varied between these highly correlating sources an average 28.8% of the possible number of direction changes. The null models show highly consistent correlation and lag structure between DMN nodes both in continuous and dynamic analysis. The mean time lag of a null-model over time between all denoised DMN nodes was 0.0s and, thus the probability of having either DMNpcc or DMNvmpf as a preceding component is near equal. All the lag values of highest correlating tICA pairs over subjects lie within the standard deviation range of a null-model in whole time window analysis, supporting the earlier findings that there is a consistent temporal lag structure across groups of individuals. However, in dynamic analysis, there are lag values exceeding the threshold of significance of a null-model meaning that there might be biologically meaningful variation in this measure. Taken together the variability in lag and the presence of high activity peaks during strong connectivity indicate that individual avalanches may play an important role in defining dynamic independence in resting state connectivity within networks.

The "Air in the CT X-ray Tube Oil" Artifact-Examples of the Quality Control Images and the Evaluation of Four Potential Clinical Patients' Head Computed Tomography Cases.

We present a newly reposted scanner-based artifact-with 4 potential patients' head computed tomography (CT) cases-the "Air in the CT X-ray Tube Oil" artifact with a 64-slice multidetector CT. This artifact mimics diseases, which cause hypodense findings in CT images. It can be difficult to notice in the clinical patient imaging but can be also very difficult to verify in quality control tests.

Justification and active guideline implementation for spine radiography referrals in primary care.

Background Spinal disorders are a major public health problem. Appropriate diagnostic imaging is an essential part in the management of back complaints. Nevertheless, inappropriate imaging increases population collective dose and health costs without improving outcome. Purpose To determine the effects of active implementation of referral guidelines on the number and justification of spine radiography in primary care in one city. Material and Methods Specified guidelines for spine radiography were distributed to referring practitioners altogether three times during the study period. Educational lectures were provided before the guidelines were taken into use. The guidelines were also made available via the intranet. The number of spine radiography referrals during similar 6-month periods in the year preceding the interventions and the following 2 years was analyzed. Justification of 448 spine radiographs was assessed similarly. Results After interventions, the total number of spine radiography examinations decreased by 48% (P < 0.001) and that of cervical spine radiography by 46% ( P < 0.001), thoracic spine by 53% ( P < 0.001), and lumbar spine by 47% ( P < 0.001). The results persisted after 1-year follow-up. Before interventions, 24% of the cervical, 46% of the thoracic, and 32% of the lumbar spine radiography referrals were justified. After interventions, only justification of lumbar spine radiography improved significantly, 64% being justified ( P = 0.005). Conclusion Spine radiography in primary care can be reduced significantly by active referral guideline implementation. The proportion of inappropriate radiography was unexpectedly high. Thus, further education and studies concerning the appropriate use of spinal radiography seems to be needed.

The effect of zoledronic acid on type and volume of Modic changes among patients with low back pain.

BACKGROUND: Modic changes (MC) are associated with low back pain (LBP). In this study, we compared changes in size and type of MC, after a single intravenous infusion of 5 mg zoledronic acid (ZA) or placebo, among chronic LBP patients with MC on magnetic resonance imaging (MRI), and evaluated whether the MRI changes correlate with symptoms. METHODS: All patients (N = 19 in ZA, 20 in placebo) had MRI at baseline (0.23-1.5 T) and at one year (1.5-3 T). We evaluated the level, type and volume of all the MC. The MC were classified into M1 (M1 (100%)), predominating M1 (M1/2 (65:35%)) or predominating M2 (M1/2 (35:65%)), and M2 (M2 (100%)). The first two were considered M1-dominant, and the latter two M2-dominant. Volumes of M1 and M2 were calculated separately for the primary MC, which was assumed to cause the symptoms, and the other MC. We analysed the one-year treatment differences in M1 and M2 volumes using analysis of covariance with adjustments for age, sex, body mass index, and smoking. The correlations between the MRI changes and the changes in LBP symptoms were analysed using Pearson correlations. RESULTS: In the ZA group, 84.2% of patients had M1-dominant primary MC at baseline, compared to 50% in the placebo group (p = 0.041). The primary MC in the ZA group converted more likely to M2-dominant (42.1% ZA, 15% placebo; p = 0.0119). The other MC (15 ZA, 8 placebo) were on average 42% smaller and remained largely M2-dominant. The M1 volume of the primary MC decreased in the ZA group, but increased in the placebo group (-0.83 cm3 vs 0.91 cm3; p = 0.21). The adjusted treatment difference for M1 volume was -1.9 cm3 (95% CI -5.0 to 1.2; p = 0.22) and for M2 volume 0.23 cm3 (p = 0.86). In the MC that remained M1-dominant, volume change correlated positively with increased symptoms in the placebo group, whereas the correlations were negative and weak in the ZA group. CONCLUSIONS: Zoledronic acid tended to speed up the conversion of M1-dominant into M2-dominant MC and decrease the volume of M1-dominant MC, although statistical significance was not demonstrated. TRIAL REGISTRATION: The registration number in ClinicalTrials.gov is NCT01330238 and the date of registration February 11, 2011.

Information about radiation dose and risks in connection with radiological examinations: what patients would like to know.

OBJECTIVES: To find out patients' wishes for the content and sources of the information concerning radiological procedures. METHODS: A questionnaire providing quantitative and qualitative data was prepared. It comprised general information, dose and risks of radiation, and source of information. Two tables demonstrating different options to indicate the dose or risks were also provided. Patients could give one or many votes. Altogether, 147 patients (18-85 years) were interviewed after different radiological examinations using these devices. RESULTS: 95% (139/147) of the patients wished for dose and risk information. Symbols (78/182 votes) and verbal scale (56/182) were preferred to reveal the dose, while verbal (83/164) and numerical scale (55/164) on the risk of fatal cancer were preferred to indicate the risks. Wishes concerning the course, options and purpose of the examination were also expressed. Prescriber (3.9 on a scale 1-5), information letter (3.8) and radiographer (3.3) were the preferred sources. Patients aged 66-85 years were reluctant to choose electronic channels. CONCLUSIONS: Apart from general information, patients wish for dose and risk information in connection with radiological examinations. The majority preferred symbols to indicate dose and verbal scales to indicate risks, and the preferred source of information was the prescriber or information letter. KEY POINTS: • 95% of patients expect information on the dose and risks of radiation. • Symbols and verbal scale are preferred to indicate the dose. • Verbal and numerical scales are preferred to indicate fatal cancer risk. • Patients expect information on course, options and purpose of examination. • Prescriber, information letter and radiographer are popular sources of the overall information.

MRI-guidance in percutaneous core decompression of osteonecrosis of the femoral head.

OBJECTIVES: The purpose of this study was to evaluate the usefulness of MRI-guidance for core decompression of avascular necrosis of the femoral head. MATERIALS AND METHODS: Twelve MRI-guided core decompressions were performed on patients with different stages of avascular necrosis of the femoral head. The patients were asked to evaluate their pain and their ability to function before and after the procedure and imaging findings were reviewed respectively. RESULTS: Technical success in reaching the target was 100 % without complications. Mean duration of the procedure itself was 54 min. All patients with ARCO stage 1 osteonecrosis experienced clinical benefit and pathological MRI findings were seen to diminish. Patients with more advanced disease gained less, if any, benefit and total hip arthroplasty was eventually performed on four patients. CONCLUSIONS: MRI-guidance seems technically feasible, accurate and safe for core decompression of avascular necrosis of the femoral head. Patients with early stage osteonecrosis may benefit from the procedure. KEY POINTS: • MRI is a useful guidance method for minimally invasive musculoskeletal interventions. • Bone drilling seems beneficial at early stages of avascular necrosis. • MRI-guidance is safe and accurate for bone drilling.

Attention and Working Memory in Adolescents with Autism Spectrum Disorder: A Functional MRI Study.

The present study examined attention and memory load-dependent differences in the brain activation and deactivation patterns between adolescents with autism spectrum disorders (ASDs) and typically developing (TD) controls using functional magnetic resonance imaging. Attentional (0-back) and working memory (WM; 2-back) processing and load differences (0 vs. 2-back) were analysed. WM-related areas activated and default mode network deactivated normally in ASDs as a function of task load. ASDs performed the attentional 0-back task similarly to TD controls but showed increased deactivation in cerebellum and right temporal cortical areas and weaker activation in other cerebellar areas. Increasing task load resulted in multiple responses in ASDs compared to TD and in inadequate modulation of brain activity in right insula, primary somatosensory, motor and auditory cortices. The changes during attentional task may reflect compensatory mechanisms enabling normal behavioral performance. The inadequate memory load-dependent modulation of activity suggests diminished compensatory potential in ASD.

Infra-slow EEG fluctuations are correlated with resting-state network dynamics in fMRI.

Ongoing neuronal activity in the CNS waxes and wanes continuously across widespread spatial and temporal scales. In the human brain, these spontaneous fluctuations are salient in blood oxygenation level-dependent (BOLD) signals and correlated within specific brain systems or "intrinsic-connectivity networks." In electrophysiological recordings, both the amplitude dynamics of fast (1-100 Hz) oscillations and the scalp potentials per se exhibit fluctuations in the same infra-slow (0.01-0.1 Hz) frequency range where the BOLD fluctuations are conspicuous. While several lines of evidence show that the BOLD fluctuations are correlated with fast-amplitude dynamics, it has remained unclear whether the infra-slow scalp potential fluctuations in full-band electroencephalography (fbEEG) are related to the resting-state BOLD signals. We used concurrent fbEEG and functional magnetic resonance imaging (fMRI) recordings to address the relationship of infra-slow fluctuations (ISFs) in scalp potentials and BOLD signals. We show here that independent components of fbEEG recordings are selectively correlated with subsets of cortical BOLD signals in specific task-positive and task-negative, fMRI-defined resting-state networks. This brain system-specific association indicates that infra-slow scalp potentials are directly associated with the endogenous fluctuations in neuronal activity levels. fbEEG thus yields a noninvasive, high-temporal resolution window into the dynamics of intrinsic connectivity networks. These results support the view that the slow potentials reflect changes in cortical excitability and shed light on neuronal substrates underlying both electrophysiological and behavioral ISFs.

The repeatability of T2 relaxation time measurement of human knee articular cartilage.

OBJECTIVES: To assess short- and long-term repeatability of T2 relaxation time measurements of the knee articular cartilage. MATERIALS AND METHODS: The right knees of nine asymptomatic volunteers (age 30-38 years, five male, four female) were imaged at 1.5 T in three sessions 1 and 2 weeks apart. To observe short-term repeatability, the measurements were repeated three times within one of the three imaging sessions for each volunteer. T2 relaxation time was mapped using a multi-slice multi-echo spin echo sequence in axial and sagittal planes. Cartilage was manually segmented and repeatability, as measured by root-mean-square coefficient of variation (CVRMS) was evaluated both for the entire bulk cartilage of each joint surface in the slice and separately for each region of interest (ROI) at different topographical locations and separately for the superficial and deep half of each ROI. RESULTS: For bulk T2, the long-term repeatability was 3.2, 5.4, and 3.7%, and the short-term reproducibility was 3.9, 3.9, and 3.4% for bulk femoral, tibial, and patellar cartilage, respectively. There were no significant differences between long-term and short-term repeatability in superficial or deep cartilage when comparing CVRMS values (p = 0.338 and 0.700, respectively). For individual ROIs, the repeatability varied between 2.5 and 22.2% depending on the topographical location. CONCLUSION: The current results show mostly good repeatability. However, there were remarkable variations of T2 between bulk cartilage and different ROIs, bulk cartilage showing better repeatability. With careful patient positioning T2 can be accurately determined for different cartilage surfaces.

DTI abnormalities in adults with past history of attention deficit hyperactivity disorder: a tract-based spatial statistics study.

BACKGROUND: Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique enabling visualization and measurement of white matter tracts. Attention deficit hyperactivity disorder (ADHD) has been studied with DTI earlier with variable results, yet there is little research on remitted ADHD. PURPOSE: To compare the brain white matter between ADHD drug naïve subjects whose ADHD symptoms have mostly subsided and healthy controls. MATERIAL AND METHODS: Tract-based spatial statistics (TBSS) was used to compare 30 subjects with adolescent ADHD with control subjects at the age of 22-23 years. The study population was derived from a population-based Northern Finland Birth Cohort 1986. Fractional anisotropy (FA), mean diffusivity (MD), and measures of diffusion direction (λ1-3) were calculated. Permutation testing was used to test for differences in mean values of FA, MD, and λ1-3 between the groups. The results were corrected for multiple comparisons across the whole white matter skeleton. RESULTS: The ADHD group showed increased FA related to decreased radial diffusivity in the left forceps minor (P < 0.05). In the vicinity along the same tract, axial diffusion was significantly decreased without any significant effect on FA. No between-group difference in MD was observed. Regressor analysis revealed no gender-, IQ- or GAF-related changes. After removal of left handed subjects the statistical significance was only barely lost. CONCLUSION: In a setting with remitted ADHD, the results may represent a compensatory mechanism in the left forceps minor.

Altered resting-state activity in seasonal affective disorder.

At present, our knowledge about seasonal affective disorder (SAD) is based mainly up on clinical symptoms, epidemiology, behavioral characteristics and light therapy. Recently developed measures of resting-state functional brain activity might provide neurobiological markers of brain disorders. Studying functional brain activity in SAD could enhance our understanding of its nature and possible treatment strategies. Functional network connectivity (measured using ICA-dual regression), and amplitude of low-frequency fluctuations (ALFF) were measured in 45 antidepressant-free patients (39.78 ± 10.64, 30 ♀, 15 ♂) diagnosed with SAD and compared with age-, gender- and ethnicity-matched healthy controls (HCs) using resting-state functional magnetic resonance imaging. After correcting for Type 1 error at high model orders (inter-RSN correction), SAD patients showed significantly increased functional connectivity in 11 of the 47 identified RSNs. Increased functional connectivity involved RSNs such as visual, sensorimotor, and attentional networks. Moreover, our results revealed that SAD patients compared with HCs showed significant higher ALFF in the visual and right sensorimotor cortex. Abnormally altered functional activity detected in SAD supports previously reported attentional and psychomotor symptoms in patients suffering from SAD. Further studies, particularly under task conditions, are needed in order to specifically investigate cognitive deficits in SAD.

MRI-guided percutaneous retrograde drilling of osteochondritis dissecans of the talus: a feasibility study.

OBJECTIVES: The purpose of this study was to evaluate the feasibility of MRI guidance for percutaneous retrograde drilling in the treatment of osteochondritis dissecans of the talus (OCDT). METHODS: Four patients, one juvenile and three adults, with one OCDT lesion each and persisting ankle pain after conservative treatment, were treated with MRI-guided retrograde drilling. All lesions were stable and located in the middle or posterior medial third of the talar dome. Pain relief and the ability to return to normal activities were assessed during clinical follow-up. MRI and plain film radiographs were used for imaging follow-up. RESULTS: Technical success was 100% with no complications and with no damage to the overlying cartilage. All patients experienced some clinical benefit, although only one had complete resolution of pain and one had a relapse leading to surgical treatment. Changes in the pathological imaging findings were mostly very slight during the follow-up period. CONCLUSIONS: MRI guidance seems accurate, safe and technically feasible for retrograde drilling of OCDT. Larger series are needed to reliably assess its clinical value. KEY POINTS: • MRI serves as a useful guidance method for numerous mini-invasive applications. • Retrograde drilling is a cartilage-sparing alternative in the treatment of osteochondritis dissecans. • MRI guidance seems feasible for treatment of osteochondritis dissecans of the talus.

Efficacy of zoledronic acid for chronic low back pain associated with Modic changes in magnetic resonance imaging.

BACKGROUND: Modic changes (MC) are associated with low back pain (LBP), but effective treatments are lacking. The aim of this randomized, placebo-controlled, double-blinded trial was to evaluate the efficacy of zoledronic acid (ZA) for chronic LBP among patients with MC in magnetic resonance imaging (MRI). METHODS: Inclusion criteria were LBP lasting ≥3 months, with an intensity of ≥6 on a 10-cm VAS or an Oswestry Disability Index (ODI) of ≥30%, and MC in MRI. Patients were randomized into single intravenous infusion of ZA 5 mg (n = 20), or placebo (n = 20) groups. The primary outcome was LBP intensity, secondary outcomes leg pain intensity, ODI, health-related quality of life (RAND-36), lumbar flexibility, sick leaves and use of pain medication. The treatment differences at one month and one year were analysed using ANCOVA with adjustment for the baseline score. RESULTS: The mean difference (MD) between the groups in the primary outcome, intensity of LBP, was 1.4 (95% confidence intervals (CI) 0.01 to 2.9) in favour of ZA at one month. We observed no significant between-group difference in the intensity of LBP at one year (MD 0.7; 95% CI -1.0 to 2.4) or in secondary outcomes at any time point except that 20% of patients in the ZA group used non-steroidal anti-inflammatory drugs at one year compared to 60% in the placebo group (P = 0.022). Acute phase reactions (fever, flu-like symptoms, arthralgia) emerged in 95% of the patients in the ZA group, compared to 35% in the placebo group. CONCLUSIONS: ZA was effective in reducing the intensity of LBP in the short term and in reducing the use of NSAIDs within the time span of one year among patients with chronic LBP and MC confirmed in MRI. Although the results seem encouraging, larger studies are required to analyse the effectiveness and safety of ZA for patients with MC. TRIAL REGISTRATION: ClinicalTrial.gov identifier NCT01330238.

Bone mineral density and geometry parameters determined in vitro from dual-energy digital radiography images in the assessment of bone maximal load of reindeer femora.

BACKGROUND: Dual-energy digital radiography (DEDR) has been shown to be a potential method to determine bone mineral density (BMD) and predict maximal load with similar accuracy as standard bone densitometry using DXA (dual-energy X-ray absorptiometry). In addition to bone density, bone geometry has also been shown to have effect on bone fragility and fracture risk. PURPOSE: To examine the combination of BMD and geometry parameters, as determined from a DEDR experiment, to predict bone maximal load. MATERIAL AND METHODS: Reindeer femora (n = 47) were imaged at two energies (79 kVp and 100 kVp) using a clinical digital radiography system. BMD was determined in four regions from these images using the DXA calculation principle. Various geometrical parameters were determined from the 79 kVp image. Femora were mechanically tested using axial loading configuration. Pearson correlation coefficients were determined between geometrical parameters and BMDs or maximal load. Multiple stepwise linear regression analysis was used to find the best combination to predict bone maximal load. RESULTS: From the geometrical parameters, femoral shaft diameter (FSD) and femoral neck axis length (FNAL) correlated best with the maximal load (r = 0.629 and r = 0.446, P < 0.01, respectively). The best combination of parameters to predict bone fragility was BMD at Ward's triangle, FSD and FNAL (r = 0.787, P < 0.05), whereas the correlation coefficient between BMD at Ward's triangle and maximal load was 0.653 (P < 0.05). CONCLUSION: The combination of DEDR-based BMD and geometrical parameters predicts reindeer bone maximal load with reasonable accuracy and the combined analysis improves the prediction of maximal load compared to BMD prediction only.

Body mass index is associated with lumbar disc degeneration in young Finnish males: subsample of Northern Finland birth cohort study 1986.

BACKGROUND: The role of environmental factors in lumbar intervertebral disc degeneration (DD) in young adults is largely unknown. Therefore, we investigated whether body mass index (BMI), smoking, and physical activity are associated with lumbar DD among young adults. METHODS: The Oulu Back Study (OBS) is a subpopulation of the 1986 Northern Finland Birth Cohort (NFBC 1986) and it originally included 2,969 children. The OBS subjects received a postal questionnaire, and those who responded (N = 1,987) were invited to the physical examination. The participants (N = 874) were invited to lumbar MRI study. A total of 558 young adults (325 females and 233 males) underwent MRI that used a 1.5-T scanner at the mean age of 21. Each lumbar intervertebral disc was graded as normal (0), mildly (1), moderately (2), or severely (3) degenerated. We calculated a sum score of the lumbar DD, and analyzed the associations between environmental risk factors (smoking, physical activity and weight-related factors assessed at 16 and 19 years) and DD using ordinal logistic regression, the results being expressed as cumulative odds ratios (COR). All analyses were stratified by gender. RESULTS: Of the 558 subjects, 256 (46%) had no DD, 117 (21%) had sum score of one, 93 (17%) sum score of two, and 92 (17%) sum score of three or higher. In the multivariate ordinal logistic regression model, BMI at 16 years (highest vs. lowest quartile) was associated with DD sum score among males (COR 2.35; 95% CI 1.19-4.65) but not among females (COR 1.29; 95% CI 0.72-2.32). Smoking of at least four pack-years was associated with DD among males, but not among females (COR 2.41; 95% CI 0.99-5.86 and 1.59; 95% 0.67-3.76, respectively). Self-reported physical activity was not associated with DD. CONCLUSIONS: High BMI at 16 years was associated with lumbar DD at 21 years among young males but not among females. High pack-years of smoking showed a comparable association in males, while physical activity had no association with DD in either gender. These results suggest that environmental factors are associated with DD among young males.

A new immunometabolic perspective of intervertebral disc degeneration.

Intervertebral disc (IVD) degeneration is a common finding on spine imaging that increases in prevalence with age. IVD degeneration is a frequent cause of low back pain, which is a leading cause of disability. The process of IVD degeneration consists of gradual structural change accompanied by severe alterations in metabolic homeostasis. IVD degeneration, like osteoarthritis, is a common comorbidity in patients with obesity and type 2 diabetes mellitus, two metabolic syndrome pathological conditions in which adipokines are important promoters of low-grade inflammation, extracellular matrix degradation and fibrosis. Impairment in white adipose tissue function, due to the abnormal fat accumulation in obesity, is characterized by increased production of specific pro-inflammatory proteins such as adipokines by white adipose tissue and of cytokines such as TNF by immune cells of the stromal compartment. Investigations into the immunometabolic alterations in obesity and type 2 diabetes mellitus and their interconnections with IVD degeneration provide insights into how adipokines might affect the pathogenesis of IVD degeneration and impair IVD function and repair. Toll-like receptor-mediated signalling has also been implicated as a promoter of the inflammatory response in the metabolic alterations associated with IVD and is thus thought to have a role in IVD degeneration. Pathological starvation, obesity and adipokine dysregulation can result in immunometabolic alterations, which could be targeted for the development of new therapeutics.

Effects of repeatability measures on results of fMRI sICA: a study on simulated and real resting-state effects.

Spatial independent components analysis (sICA) has become a widely applied data-driven method for fMRI data, especially for resting-state studies. These sICA approaches are often based on iterative estimation algorithms and there are concerns about accuracy due to noise. Repeatability measures such as ICASSO, RAICAR and ARABICA have been introduced as remedies but information on their effects on estimates is limited. The contribution of this study was to provide more of such information and test if the repeatability analyses are necessary. We compared FastICA-based ordinary and repeatability approaches concerning mixing vector estimates. Comparisons included original FastICA, FSL4 Melodic FastICA and original and modified ICASSO. The effects of bootstrapping and convergence threshold were evaluated. The results show that there is only moderate improvement due to repeatability measures and only in the bootstrapping case. Bootstrapping attenuated power from time courses of resting-state network related ICs at frequencies higher than 0.1 Hz and made subsets of low frequency oscillations more emphasized IC-wise. The convergence threshold did not have a significant role concerning the accuracy of estimates. The performance results suggest that repeatability measures or strict converge criteria might not be needed in sICA analyses of fMRI data. Consequently, the results in existing sICA fMRI literature are probably valid in this sense. A decreased accuracy of original bootstrapping ICASSO was observed and corrected by using centrotype mixing estimates but the results warrant for thorough evaluations of data-driven methods in general. Also, given the fMRI-specific considerations, further development of sICA methods is strongly encouraged.