MRI evaluation of foraminal changes in the cervical spine with assistance of a novel compression device.

Standard supine Magnetic Resonance Imaging (MRI) does not acquire images in a position where most patients with intermittent arm radiculopathy have symptoms. The aim of this study was to test the feasibility of a new compression device and to evaluate image quality and foraminal properties during a Spurling test under MRI acquisition. Ten asymptomatic individuals were included in the study (6 men and 4 women; age range 27 to 55 years). First, the subjects were positioned in the cervical compression device in a 3 T MRI scanner, and a volume T2 weighted (T2w) sequence was acquired in a relaxed supine position (3 min). Thereafter, the position and compressive forces on the patient's neck (provocation position) were changed by maneuvering the device from the control room, with the aim to simulate a Spurling test, causing a mild foraminal compression, followed by a repeated image acquisition (3 min). A radiologist measured the blinded investigations evaluating cervical lordosis (C3-C7), foraminal area on oblique sagittal images and foraminal cross-distance in the axial plane. A total of three levels (C4-C7) were measured on the right side on each individual. Measurements were compared between the compressed and relaxed state. Reliability tests for inter- and intraclass correlation were performed. The device was feasible to use and well tolerated by all investigated individuals. Images of adequate quality was obtained in all patients. A significant increase (mean 9.4, p = 0.013) in the cervical lordosis and a decreased foraminal cross-distance (mean 32%, p < 0.001) was found, during the simulated Spurling test. The area change on oblique sagittal images did not reach a statistically significant change. The reliability tests on the quantitative measures demonstrated excellent intraobserver reliability and moderate to good interobserver reliability. Applying an individualized provocation test on the cervical spine, which simulates a Spurling test, during MRI acquisition was feasible with the novel device and provided images of satisfactory quality. MRI images acquired with and without compression showed changes in cervical lordosis and foraminal cross distance indicating the possibility of detecting changes of the foraminal properties. As a next step, the method is to be tested on symptomatic patients.

Different disc characteristics between young elite skiers with diverse training histories revealed with a novel quantitative magnetic resonance imaging method.

PURPOSE: To evaluate if there are differences in thoraco-lumbar disc characteristics between elite skiers and non-athletic controls as well as between different types of elite skiers, with diverse training histories, using a novel quantitative MRI method. METHODS: The thoraco-lumbar spine of 58 elite skiers (age = 18.2 ± 1.1 years, 30 males) and 26 normally active controls (age = 16.4 ± 0.6 years, 9 males) was examined using T2w-MRI. Disc characteristics were compared quantitatively between groups using histogram and regional image analyses to determine delta peak and T2-values in five sub-regions. RESULTS: A statistical difference in the delta peak value was found between skiers and controls (p <0.001), reflecting higher degree of disc degeneration. The histogram analysis also revealed that the type of training determines where and to what extent the changes occur. Alpine skiers displayed lumbar changes, while mogul skiers displayed changes also in the thoracic spine. Alpine skiers with diverse training dose differed in delta peak value (p = 0.005), where skiers with highest training dose displayed less changes. Regional T2-value differences were found in skiers with divergent training histories (p <0.05), reflecting differences in disc degeneration patterns, foremost within the dorsal annulus. CONCLUSION: Differences in quantitative disc characteristics were found not only between elite skiers and non-athletic controls but also between subgroups of elite skiers with diverse training histories. The differences in the disc measures, reflecting tissue degradation, are likely related to type and intensity of the physical training. Future studies are encouraged to explore the relation between disc functionality, training history and pain to establish adequate prevention and rehabilitation programs.

Innominate Salter osteotomy using resorbable screws: a retrospective case series and presentation of a new concept for fixation.

PURPOSE: The Salter innominate osteotomy (SIO) in children is traditionally stabilized by Kirschner-wires, which have issues regarding stability, infection and the need to be extracted. To counter these disadvantages, we present a surgical method to stabilize SIO with modern resorbable poly lactic-co-glycolic acid screws. Using a case series of 21 patients treated with SIO for developmental dysplasia of the hip or Legg-Calvé-Perthes disease we evaluate the feasibility of the method. METHODS: The integrity of the osteotomy was interpreted by radiological measurements of acetabular index, centre-edge angle and Reimer's index. Perioperative and postoperative complications were evaluated. RESULTS: Radiographic evaluation revealed a stable osteotomy and favourable development in all measured parameters with the exception of one patient who fell out of bed the first day postoperatively. No other perioperative surgical complications were observed and there were no local reactions to the resorbable screws. CONCLUSION: Modern resorbable screws carry multiple benefits both for the patient and the surgeon. In our case series the implants provided sufficient stability and the implants caused no local reactions. The use of resorbable implants gave the surgeon a wider range of possible screw placements and avoided the need for implant removal. LEVEL OF EVIDENCE: Level IV - Case series.

The importance of level stratification for quantitative MR studies of lumbar intervertebral discs: a cross-sectional analysis in 101 healthy adults.

PURPOSE: To investigate whether quantitative T2-times depend on lumbar intervertebral disc (IVD) level. METHODS: The lumbar spine (Th12/L1-L5/S1) of 101 participants (53.5% female, 30.0[± 3.6]years, 173.5[± 9.6]cm and 69.9[± 13.4]kg), without history of back pain, was examined on a 3T scanner with sagittal T2-mapping. All IVDs were stratified according to Pfirrmann grade and lumbar level, with mean T2-time determined for the entire IVD volume and in five subregions of interests. RESULTS: Significant level-dependent T2-time differences were detected, both for the entire IVD volume and its subregions. For the entire IVD volume, Pfirrmann grade 2 IVDs displayed 9-18% higher T2-times in Th12/L1 IVDs compared to L2/L3-L5/S1 IVDs (0.001 > p < 0.004) and significantly different T2-times in L1/L2-L2/L3 IVDs compared to most of the IVDs in the lower lumbar spine. In Pfirrmann grades 1, 3 and 4 IVDs, no significant level-dependent T2-time differences were observed for the entire IVD. More pronounced results were observed when comparing IVD subregions, with significant level-dependent differences also within Pfirrmann grade 1 and grade 3 IVDs. For example, in posterior IVD subregions mean T2-time was 80-82% higher in Th12/L1 compared to L3/L4-L4/L5 Pfirrmann grade 1 IVDs (p < 0.05) and 10-14% higher in L5/S1 compared to L3/L4-L4/L5 Pfirrmann grade 3 IVDs (0.02 > p < 0.001). DISCUSSION: Significant level-dependent T2-time differences within several Pfirrmann grades, both for the entire IVD volume and for multiple IVD subregions, were shown in this large cohort study. The T2-time differences between levels existed in both non-degenerated and degenerated IVDs. These findings show the importance of stratifying for lumbar level when quantitative IVD studies are performed using T2-mapping. These slides can be retrieved under Electronic Supplementary Material.

Low back pain patients and controls display functional differences in endplates and vertebrae measured with T2-mapping.

PURPOSE: The aim was to (1) verify our previous finding that endplates (EPs) display load-induced T2-changes, (2) investigate whether vertebrae display load-induced T2-changes and (3) investigate whether EPs and vertebrae in LBP patients and controls display T2-differences during conventional unloaded MRI and axial loaded MRI (alMRI). METHODS: Twenty-seven patients (mean 39 years) and 12 (mean 38 years) controls were examined with T2-mapping on a 1.5 T scanner during conventional unloaded MRI and subsequently during alMRI (Dynawell® loading device), separated by approximately 20 min. For determination of EP and vertebral T2-values, volumetric regions of interest were manually segmented. Each vertebra was then divided into half to obtain superior and inferior units. The presence of EP changes (visual inhomogeneity in the EP zone), Schmorl's nodules and Modic changes were registered. RESULTS: For conventional unloaded MRI, the T2-values in the superior and inferior vertebral units and the EPs were significantly higher in the patients compared with controls (p < 0.03, p < 0.006) even when adjusted for the presence of Modic changes, Schmorl's nodules and EP signal changes. alMRI induced significant changes in the superior EPs of the patients (p < 0.001). Additionally, the T2-value differed significantly between the superior and inferior EP, as well as between the superior and inferior vertebra with higher values in the inferior units (p < 0.001). CONCLUSION: This study demonstrated significantly higher EP and vertebral T2-values in LBP patients in comparison with controls. In addition, alMRI induced significant T2-changes in the superior EPs for patients but not for controls. Importantly, the T2-differences between the groups may indicate that EPs and vertebrae in LBP patients have altered biodynamical characteristics compared to controls and the higher T2-values measured in patients may represent early inflammation or impaired nutritional transport. These slides can be retrieved from electronic supplementary material.

Axial loading during MRI reveals deviant characteristics within posterior IVD regions between low back pain patients and controls.

PURPOSE: To investigate differences in functional intervertebral disk (IVD) characteristics between low back pain (LBP) patients and controls using T2-mapping with axial loading during MRI (alMRI). METHODS: In total, 120 IVDs in 24 LBP patients (mean age 39 years, range 25-69) were examined with T2-mapping without loading of the spine (uMRI) and with alMRI (DynaWell® loading device) and compared with 60 IVDs in 12 controls (mean age 38 years, range 25-63). The IVD T2-value was acquired after 20-min loading in five regions of interests (ROI), ROI1-5 from anterior to posterior. T2-values were compared between loading states and cohorts with adjustment for Pfirrmann grade. RESULTS: In LBP patients, mean T2-value of the entire IVD was 64 ms for uMRI and 66 ms for alMRI (p = 0.03) and, in controls, 65 ms and 65 ms (p = 0.5). Load-induced T2-differences (alMRI-uMRI) were seen in all ROIs in both patients (0.001 > p < 0.005) and controls (0.0001 > p < 0.03). In patients, alMRI induced an increase in T2-value for ROI1-3 (23%, 18% and 5%) and a decrease for ROI4 (3%) and ROI5 (24%). More pronounced load-induced decrease was detected in ROI4 in controls (9%/p = 0.03), while a higher absolute T2-value was found for ROI5 during alMRI in patients (38 ms) compared to controls (33 ms) (p = 0.04). CONCLUSION: The alMRI-induced differences in T2-value in ROI4 and ROI5 between patients and controls most probably indicate biomechanical impairment in the posterior IVD regions. Hence, alMRI combined with T2-mapping offers an objective and clinical feasible tool for biomechanical IVD characterization that may deepen the knowledge regarding how LBP is related to altered IVD matrix composition. These slides can be retrieved under Electronic Supplementary Material.

With axial loading during MRI diurnal T2-value changes in lumbar discs are neglectable: a cross sectional study.

BACKGROUND: Axial loading during MRI (alMRI) combined with T2 mapping recently was shown as a promising method to reveal biomechanical intervertebral disc (IVD) characteristics. This feasibility study aims to investigate whether there is a diurnal variation in the IVD T2-value when using alMRI. This is of importance for the planning of when to perform alMRI investigations and for interpretations of alMRI findings in relation to clinical symptoms. METHODS: Six healthy volunteers (30 lumbar discs), were examined with alMRI at three different sessions during 1 day. To be representative for a low back pain cohort in terms of age and IVD degeneration the included participants had a wide age range (27-63y) and all Pfirrmann grades represented. The T2-values were measured in five IVD regions of interest (ROI). The ROIs were equally large in sagittal plane with ROI1 representing anterior parts of the IVD, ROI5 posterior IVD parts and ROI2-4 the parts in between. RESULTS: T2-values of the entire IVD varied between 38 and 138 ms at 7 am, 33-143 ms at 11.30 am, and 31-147 ms at 4 pm with large regional IVD variations at all time points. No significant alterations of the T2-values over the day were found, neither for the entire IVD (p = 0.4) nor for the various ROIs (p = 0.2-1.0). Neither when correlated to Pfirrmann grade, any significant diurnal T2-value changes were found. CONCLUSIONS: With alMRI, only minor diurnal T2-value changes were found in the lumbar discs. Nonsignificant and neglectable diurnal changes are advantageous both for research purposes, as well as in the clinical setting, giving comparable and robust data regardless of at what time-point the alMRI is performed.

Axial loading during MRI influences T2-mapping values of lumbar discs: a feasibility study on patients with low back pain.

PURPOSE: To investigate whether axial loading of the spine during MRI (alMRI) instantaneously induces changes in biochemical disc features as reflected by altered quantitative T2 values in patients with chronic low back pain (LBP). METHODS: T2 mapping was performed on 11 LBP patients (54 lumbar discs) during the conventional unloaded MRI and subsequent alMRI. Each disc was divided into five volumetric regions of interests (ROIs), anterior annulus fibrosus (AF) (ROI 1), the interface anterior AF-nucleus pulposus (NP) (ROI 2), NP (ROI 3), the interface NP-posterior AF (ROI 4), and the posterior AF (ROI 5). The mean T2 values for each ROI were compared between MRI and alMRI and correlated with degeneration grade (Pfirrmann), disc angle, and disc level. RESULTS: With alMRI, T2 values increased significantly in the whole disc as well as in various parts of the disc with an increase in ROI 1-3 and a decrease in ROI 5. The changes in T2 values correlated to degeneration grade, changes in disc angle, and lumbar level. CONCLUSION: alMRI instantaneously induces T2-value changes in lumbar discs and is, thus, a feasible method to reveal dynamic, biochemical disc features in patients with chronic LBP.

Increased plasma homocysteine levels without signs of vitamin B12 deficiency in patients with multiple sclerosis assessed by blood and cerebrospinal fluid homocysteine and methylmalonic acid.

OBJECTIVE: The aim of this study was to evaluate if multiple sclerosis (MS) is associated with vitamin B12 (cobalamin) deficiency. METHODS: We measured serum vitamin B12, plasma folate, serum methylmalonic acid (MMA), plasma homocysteine (tHcy) and also cerebrospinal fluid (CSF) MMA and tHcy in 72 patients with MS and 23 controls. RESULTS: The mean plasma tHcy level was significantly increased in MS patients (11.6 micromol/L) compared with controls (7.4 micromol/L) (P = 0.002). Seven patients showed low serum vitamin B12 levels but only one of them had concomitant high plasma tHcy. None of them showed high serum MMA. Plasma or blood folate levels did not differ between MS patients and controls. We found no significant differences in mean values or frequency of pathological tests of serum B12, serum MMA, mean corpuscular volume (MCV), haemoglobin concentration, CSF tHcy or CSF MMA between patients and healthy subjects. There were no correlations between CSF and serum/plasma levels of MMA or tHcy. Serum vitamin B12, serum MMA, plasma tHcy, CSF Hcy or CSF MMA were not correlated to disability status, activity of disease, duration of disease or age. CONCLUSIONS: The relevance of the increased mean value of plasma tHcy thus seems uncertain and does not indicate functional vitamin B12 deficiency. We can not, however, exclude the possibility of a genetically induced dysfunction of the homocysteine metabolism relevant for the development of neuroinflammation/degeneration. Our findings indicate that, regardless of a significant increase in plasma tHcy in MS patients, the MS disease is not generally associated with vitamin B12 deficiency since we did not find any other factors indicating vitamin B12 deficiency. Analysis of CSF MMA and CSF tHcy, which probably reflects the brain vitamin B12 status better than serum, are not warranted in MS. We conclude that B12 deficiency, in general, is not associated with MS.