2.5-Minute Fast Brain MRI with Multiple Contrasts in Acute Ischemic Stroke

PURPOSE

To assess the performance of a 2.5-minute multi-contrast brain MRI sequence (NeuroMix) in diagnosing acute cerebral infarctions.

METHODS

Adult patients with a clinical suspicion of acute ischemic stroke were retrospectively included. Brain MRI at 3 T included NeuroMix and routine clinical MRI (cMRI) sequences, with DWI/ADC, T2-FLAIR, T2-weighted, T2*, SWI-EPI, and T1-weighted contrasts. Three radiologists (R1-3) independently assessed NeuroMix and cMRI for the presence of acute infarcts (DWI ↑, ADC = or ↓) and infarct-associated abnormalities on other image contrasts. Sensitivity, specificity, and the area under the receiver operating characteristic curve (AUC) were calculated and compared using DeLong's test. Inter- and intra-rater agreements were studied with kappa statistics. Relative DWI (rDWI) and T2-FLAIR (rT2-FLAIR) signal intensity for infarctions were semi-automatically rendered, and the correlation between methods was evaluated.

RESULTS

According to the reference standard, acute infarction was present in 34 out of 44 (77%) patients (63 ± 17 years, 31 men). Other infarct-associated signal abnormalities were reported in similar frequencies on NeuroMix and cMRI (p > .08). Sensitivity for infarction detection was 94%, 100%, and 94% evaluated by R1, R2, R3, for NeuroMix and 94%, 100%, and 100% for cMRI. Specificity was 100%, 90%, and 100% for NeuroMix and 100%, 100%, and 100% for cMRI. AUC for NeuroMix was .97, .95, and .97 and .97, 1, and 1 for cMRI (DeLong p = 1, .32, .15), respectively. Inter- and intra-rater agreement was κ = .88-1. The correlation between NeuroMix and cMRI was R = .73 for rDWI and R = .83 for rT2-FLAIR.

CONCLUSION

Fast multi-contrast MRI NeuroMix has high diagnostic performance for detecting acute cerebral infarctions.

Fully Automatic Method for Reliable Spinal Cord Compartment Segmentation in Multiple Sclerosis

BACKGROUND AND PURPOSE

Fully automatic quantification methods of spinal cord compartments are needed to study pathologic changes of the spinal cord GM and WM in MS in vivo. We propose a novel method for automatic spinal cord compartment segmentation (SCORE) in patients with MS.

MATERIALS AND METHODS

The cervical spinal cords of 24 patients with MS and 24 sex- and age-matched healthy controls were scanned on a 3T MR imaging system, including an averaged magnetization inversion recovery acquisition sequence. Three experienced raters manually segmented the spinal cord GM and WM, anterior and posterior horns, gray commissure, and MS lesions. Subsequently, manual segmentations were used to train neural segmentation networks of spinal cord compartments with multidimensional gated recurrent units in a 3-fold cross-validation fashion. Total intracranial volumes were quantified using FreeSurfer.

RESULTS

The intra- and intersession reproducibility of SCORE was high in all spinal cord compartments (eg, mean relative SD of GM and WM: ≤ 3.50% and ≤1.47%, respectively) and was better than manual segmentations (all P < .001). The accuracy of SCORE compared with manual segmentations was excellent, both in healthy controls and in patients with MS (Dice similarity coefficients of GM and WM: ≥ 0.84 and ≥0.92, respectively). Patients with MS had lower total WM areas (P < .05), and total anterior horn areas (P < .01 respectively), as measured with SCORE.

CONCLUSIONS

We demonstrate a novel, reliable quantification method for spinal cord tissue segmentation in healthy controls and patients with MS and other neurologic disorders affecting the spinal cord. Patients with MS have reduced areas in specific spinal cord tissue compartments, which may be used as MS biomarkers.

A 78 Seconds Complete Brain MRI Examination in Ischemic Stroke: A Prospective Cohort Study

BACKGROUND

Fast 78-second multicontrast echo-planar MRI (EPIMix) has shown good diagnostic performance for detecting infarctions at a comprehensive stroke center, but its diagnostic performance has not been evaluated in a prospective study at a primary stroke center.

PURPOSE

To prospectively determine whether EPIMix was noninferior in detecting ischemic lesions compared to routine clinical MRI.

STUDY TYPE

Prospective cohort study.

POPULATION

A total of 118 patients with acute MRI and symptoms of ischemic stroke.

FIELD STRENGTH AND SEQUENCE

A 3 T. EPIMix (echo-planar based: T1-FLAIR, T2-weighted, T2-FLAIR, T2*, DWI) and routine clinical MRI sequences (T1-weighted fast spin echo, T2-weighted PROPELLER, T2-weighted-FLAIR fast spin echo, T2* gradient echo echo-planar, and DWI spin echo echo-planar).

ASSESSMENT

Three radiologists, blinded for clinical information, assessed signs of ischemic lesions (DWI↑, ADC↓, and T2/T2-FLAIR↑) on EPIMix and routine clinical MRI, with disagreements solved in consensus with a fourth reader to establish the reference standard.

STATISTICAL TESTS

Diagnostic performance including sensitivity and specificity against the reference standard was evaluated. EPIMix sensitivity was tested for noninferiority compared to the reference standard using Nam's restricted maximum likelihood estimation (RMLE) Score. A P-value < 0.05 was considered statistically significant.

RESULTS

Of 118 patients (mean age 62 ± 16 years, 58% males), 25% (n = 30) had MRI signs of acute infarcts. EPIMix was noninferior with 97% (95% CI 83-100) sensitivity for reader 1, 100% (95% CI 88-100) sensitivity for reader 2, and 90% (95% CI 88-98) sensitivity for reader 3 vs. 93% (95% CI 78-99) sensitivity for readers 1 and 2 and 90% (95% CI 74-98) for reader 3 on routine clinical MRI. Specificity was 99% (95% CI 94-100) for reader 1, 100% (95% CI 96-100) for reader 2, and 98% (95% CI 92-100) for reader 3 on EPIMix vs. 100% (95% CI 96-100) for all readers on routine clinical MRI.

CONCLUSION

EPIMix was noninferior to routine clinical MRI for the diagnosis of acute ischemic stroke.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

Clinical Feasibility of Ultrafast Contrast-Enhanced T1-Weighted 3D-EPI for Evaluating Intracranial Enhancing Lesions in Oncology Patients: Comparison with Standard 3D MPRAGE Sequence

BACKGROUND AND PURPOSE

Contrast-enhanced 3D T1WI is a preferred sequence for brain tumor imaging despite the long scan time. This study investigated the clinical feasibility of ultrafast contrast-enhanced T1WI by 3D echo-planar imaging compared with a standard contrast-enhanced 3D MPRAGE sequence for evaluating intracranial enhancing lesions in oncology patients.

MATERIALS AND METHODS

Sixty-one patients in oncology underwent brain MR imaging including both contrast-enhanced T1WI, 3D-EPI and 3D MPRAGE, in a single examination session for evaluating intracranial tumors. Two neuroradiologists evaluated image quality, lesion conspicuity, diagnostic confidence, number and size of the lesions, and contrast-to-noise ratio measurements from the 2 different sequences.

RESULTS

Ultrafast 3D-EPI T1WI did not reveal significant differences in diagnostic confidence, contrast-to-noise ratio_{lesion/parenchyma}, and the number of enhancing lesions compared with MPRAGE (P > .05). However, ultrafast 3D-EPI T1WI revealed inferior image quality, inferior anatomic delineation and greater susceptibility artifacts with fewer motion artifacts than images obtained with MPRAGE. The mean contrast-to-noise ratio_WM/GM and visual conspicuity of the lesion on ultrafast 3D-EPI T1WI were lower than those of MPRAGE (P < .001).

CONCLUSIONS

Ultrafast 3D-EPI T1WI showed comparable diagnostic performance with sufficient image quality and a 7-fold reduction in scan time for evaluating intracranial enhancing lesions compared with standard MPRAGE, even though it was limited by an inferior image quality and frequent susceptibility artifacts. Therefore, we believe that ultrafast 3D-EPI T1WI may be a viable option in oncology patients prone to movement during imaging studies.

NeuroMix-A single-scan brain exam

PURPOSE

Implement a fast, motion-robust pulse sequence that acquires T₁ -weighted, T₂ -weighted, T₂ ^* -weighted, T₂ fluid-attenuated inversion recovery, and DWI data in one run with only one prescription and one prescan.

METHODS

A software framework was developed that configures and runs several sequences in one main sequence. Based on that framework, the NeuroMix sequence was implemented, containing motion robust single-shot sequences using EPI and fast spin echo (FSE) readouts (without EPI distortions). Optional multi-shot sequences that provide better contrast, higher resolution, or isotropic resolution could also be run within the NeuroMix sequence. An optimized acquisition order was implemented that minimizes times where no data is acquired.

RESULTS

NeuroMix is customizable and takes between 1:20 and 4 min for a full brain scan. A comparison with the predecessor EPIMix revealed significant improvements for T₂ -weighted and T₂ fluid-attenuated inversion recovery, while taking only 8 s longer for a similar configuration. The optional contrasts were less motion robust but offered a significant increase in quality, detail, and contrast. Initial clinical scans on 1 pediatric and 1 adult patient showed encouraging image quality.

CONCLUSION

The single-shot FSE readouts for T₂ -weighted and T₂ fluid-attenuated inversion recovery and the optional multishot FSE and 3D-EPI contrasts significantly increased diagnostic value compared with EPIMix, allowing NeuroMix to be considered as a standalone brain MRI application.

Control of a wireless sensor using the pulse sequence for prospective motion correction in brain MRI

PURPOSE

To synchronize and pass information between a wireless motion-tracking device and a pulse sequence and show how this can be used to implement customizable navigator interleaving schemes that are part of the pulse sequence design.

METHODS

The device tracks motion by sampling the voltages induced in 3 orthogonal pickup coils by the changing gradient fields. These coils were modified to also detect RF-transmit events using a 3D RF-detection circuit. The device could then detect and decode a set RF signatures while ignoring excitations in the parent pulse sequence. A set of unique RF signatures were then paired with a collection of navigators and used to trigger readouts on the wireless device synchronous to the pulse sequence execution. Navigator interleaving schemes were then demonstrated in 3D RF-spoiled gradient echo, T₁ -FLAIR (fluid-attenuated inversion recovery) PROPELLER (periodically rotated overlapping parallel lines with enhanced reconstruction), and T₂ -FLAIR PROPELLER pulse sequences.

RESULTS

Excitations in the parent pulse sequences were successfully rejected and the RF signatures successfully decoded. For the 3D gradient echo sequence, distortions were removed by interleaving flipped polarity navigators and taking the difference between consecutive readouts. The impact on scan duration was reduced by 54% by breaking up the navigators into smaller parts. Successful motion correction was performed using the PROPELLER pulse sequences in 3 Tesla and 1.5 Tesla MRI scanners without modifications to the device hardware or software.

CONCLUSION

The proposed RF signature-based triggering scheme enables complex interactions between the pulse sequence and a wireless device. Thus, enabling prospective motion correction that is repeatable, versatile, and minimally invasive with respect to hardware setup.

Motion-insensitive susceptibility weighted imaging

PURPOSE

To enable SWI that is robust to severe head movement.

METHODS

Prospective motion correction using a markerless optical tracker was applied to all pulse sequences. Three-dimensional gradient-echo and 3D EPI were used as reference sequences, but were expected to be sensitive to motion-induced B₀ changes, as the long TE required for SWI allows phase discrepancies to accumulate between shots. Therefore, 2D interleaved snapshot EPI was investigated for motion-robust SWI and compared with conventional 2D EPI. Repeated signal averages were retrospectively corrected for motion. The sequences were evaluated at 3 T through controlled motion experiments involving two cooperative volunteers and SWI of a tumor patient.

RESULTS

The performed continuous head motion was in the range of 5-8° rotations. The image quality of the 3D sequences and conventional 2D EPI was poor unless the rotational motion axis was parallel to B₀ . Interleaved snapshot EPI had minimal intraslice phase discrepancies due to its small temporal footprint. Phase inconsistency between signal averages was well tolerated due to the high-pass filter effect of the SWI processing. Interleaved snapshot EPI with prospective and retrospective motion correction demonstrated similar image quality, regardless of whether motion was present. Lesion depiction was equal to 3D EPI with matching resolution.

CONCLUSION

Susceptibility-based imaging can be severely corrupted by head movement despite accurate prospective motion correction. Interleaved snapshot EPI is a superior alternative for patients who are prone to move and offers SWI which is insensitive to motion when combined with prospective and retrospective motion correction.

Toward nonparametric diffusion- T1 characterization of crossing fibers in the human brain

PURPOSE

To estimate T 1 for each distinct fiber population within voxels containing multiple brain tissue types.

METHODS

A diffusion- T 1 correlation experiment was carried out in an in vivo human brain using tensor-valued diffusion encoding and multiple repetition times. The acquired data were inverted using a Monte Carlo algorithm that retrieves nonparametric distributions P ( D , R 1 ) of diffusion tensors and longitudinal relaxation rates R 1 = 1 / T 1 . Orientation distribution functions (ODFs) of the highly anisotropic components of P ( D , R 1 ) were defined to visualize orientation-specific diffusion-relaxation properties. Finally, Monte Carlo density-peak clustering (MC-DPC) was performed to quantify fiber-specific features and investigate microstructural differences between white matter fiber bundles.

RESULTS

Parameter maps corresponding to P ( D , R 1 ) 's statistical descriptors were obtained, exhibiting the expected R 1 contrast between brain tissue types. Our ODFs recovered local orientations consistent with the known anatomy and indicated differences in R 1 between major crossing fiber bundles. These differences, confirmed by MC-DPC, were in qualitative agreement with previous model-based works but seem biased by the limitations of our current experimental setup.

CONCLUSIONS

Our Monte Carlo framework enables the nonparametric estimation of fiber-specific diffusion- T 1 features, thereby showing potential for characterizing developmental or pathological changes in T 1 within a given fiber bundle, and for investigating interbundle T 1 differences.

Prospective motion correction for diffusion weighted EPI of the brain using an optical markerless tracker

PURPOSE

To enable motion-robust diffusion weighted imaging of the brain using well-established imaging techniques.

METHODS

An optical markerless tracking system was used to estimate and correct for rigid body motion of the head in real time during scanning. The imaging coordinate system was updated before each excitation pulse in a single-shot EPI sequence accelerated by GRAPPA with motion-robust calibration. Full Fourier imaging was used to reduce effects of motion during diffusion encoding. Subjects were imaged while performing prescribed motion patterns, each repeated with prospective motion correction on and off.

RESULTS

Prospective motion correction with dynamic ghost correction enabled high quality DWI in the presence of fast and continuous motion within a 10° range. Images acquired without motion were not degraded by the prospective correction. Calculated diffusion tensors tolerated the motion well, but ADC values were slightly increased.

CONCLUSIONS

Prospective correction by markerless optical tracking minimizes patient interaction and appears to be well suited for EPI-based DWI of patient groups unable to remain still including those who are not compliant with markers.

T1 -FLAIR imaging during continuous head motion: Combining PROPELLER with an intelligent marker

PURPOSE

The purpose of this work is to describe a T₁ -weighted fluid-attenuated inversion recovery (FLAIR) sequence that is able to produce sharp magnetic resonance images even if the subject is moving their head throughout the acquisition.

METHODS

The robustness to motion artifacts and retrospective motion correction capabilities of the PROPELLER (periodically rotated overlapping parallel lines with enhanced reconstruction) trajectory were combined with prospective motion correction. The prospective correction was done using an intelligent marker attached to the subject. This marker wirelessly synchronizes to the pulse sequence to measure the directionality and magnitude of the magnetic fields present in the MRI machine during a short navigator, thus enabling it to determine its position and orientation in the scanner coordinate frame. Three approaches to incorporating the marker-navigator into the PROPELLER sequence were evaluated. The specific absorption rate, and subsequent scan time, of the T₁ -weighted FLAIR PROPELLER sequence, was reduced using a variable refocusing flip-angle scheme. Evaluations of motion correction performance were done with 4 volunteers and 3 types of head motion.

RESULTS

During minimal out-of-plane movement, retrospective PROPELLER correction performed similarly to the prospective correction. However, the prospective clearly outperformed the retrospective correction when there was out-of-plane motion. Finally, the combination of retrospective and prospective correction produced the sharpest images even during large continuous motion.

CONCLUSION

Prospective motion correction of a PROPELLER sequence makes it possible to handle continuous, large, and high-speed head motions with only minor reductions in image quality.

Clinical Experience of 1-Minute Brain MRI Using a Multicontrast EPI Sequence in a Different Scan Environment

BACKGROUND AND PURPOSE

The long scan time of MR imaging is a major drawback limiting its clinical use in neuroimaging; therefore, we aimed to investigate the clinical feasibility of a 1-minute full-brain MR imaging using a multicontrast EPI sequence on a different MR imaging scanner than the ones previously reported.

MATERIALS AND METHODS

We retrospectively reviewed the records of 146 patients who underwent a multicontrast EPI sequence, including T1-FLAIR, T2-FLAIR, T2WI, DWI, and T2*WI sequences. Two attending neuroradiologists assessed the image quality of each sequence to compare the multicontrast EPI sequence with routine MR imaging protocols. We used the Wilcoxon signed rank test and McNemar test to compare the 2 MR imaging protocols.

RESULTS

The multicontrast EPI sequence generally showed sufficient image quality of >2 points using a 4-point assessment scale. Regarding image quality and susceptibility artifacts, there was no significant difference between the multicontrast EPI sequence DWI and routine DWI (P > .05), attesting to noninferiority of the multicontrast EPI, whereas there were significant differences in the other 4 sequences between the 2 MR imaging protocols.

CONCLUSIONS

The multicontrast EPI sequence showed sufficient image quality for clinical use with a shorter scan time; however, it was limited by inferior image quality and frequent susceptibility artifacts compared with routine brain MR imaging. Therefore, the multicontrast EPI sequence cannot completely replace the routine MR imaging protocol at present; however, it may be a feasible option in specific clinical situations such as screening, time-critical diseases or for use with patients prone to motion.

Oscillating diffusion-encoding with a high gradient-amplitude and high slew-rate head-only gradient for human brain imaging

PURPOSE

We investigate the importance of high gradient-amplitude and high slew-rate on oscillating gradient spin echo (OGSE) diffusion imaging for human brain imaging and evaluate human brain imaging with OGSE on the MAGNUS head-gradient insert (200 mT/m amplitude and 500 T/m/s slew rate).

METHODS

Simulations with cosine-modulated and trapezoidal-cosine OGSE at various gradient amplitudes and slew rates were performed. Six healthy subjects were imaged with the MAGNUS gradient at 3T with OGSE at frequencies up to 100 Hz and b = 450 s/mm² . Comparisons were made against standard pulsed gradient spin echo (PGSE) diffusion in vivo and in an isotropic diffusion phantom.

RESULTS

Simulations show that to achieve high frequency and b-value simultaneously for OGSE, high gradient amplitude, high slew rates, and high peripheral nerve stimulation limits are required. A strong linear trend for increased diffusivity (mean: 8-19%, radial: 9-27%, parallel: 8-15%) was observed in normal white matter with OGSE (20 Hz to 100 Hz) as compared to PGSE. Linear fitting to frequency provided excellent correlation, and using a short-range disorder model provided radial long-term diffusivities of D_∞,MD = 911 ± 72 µm² /s, D_∞,PD = 1519 ± 164 µm² /s, and D_∞,RD = 640 ± 111 µm² /s and correlation lengths of l_{c ,MD} = 0.802 ± 0.156 µm, l_{c ,PD} = 0.837 ± 0.172 µm, and l_{c ,RD} = 0.780 ± 0.174 µm. Diffusivity changes with OGSE frequency were negligible in the phantom, as expected.

CONCLUSION

The high gradient amplitude, high slew rate, and high peripheral nerve stimulation thresholds of the MAGNUS head-gradient enables OGSE acquisition for in vivo human brain imaging.

Automatic Spinal Cord Gray Matter Quantification: A Novel Approach

BACKGROUND AND PURPOSE

Currently, accurate and reproducible spinal cord GM segmentation remains challenging and a noninvasive broadly accepted reference standard for spinal cord GM measurements is still a matter of ongoing discussion. Our aim was to assess the reproducibility and accuracy of cervical spinal cord GM and WM cross-sectional area measurements using averaged magnetization inversion recovery acquisitions images and a fully-automatic postprocessing segmentation algorithm.

MATERIALS AND METHODS

The cervical spinal cord of 24 healthy subjects (14 women; mean age, 40 ± 11 years) was scanned in a test-retest fashion on a 3T MR imaging system. Twelve axial averaged magnetization inversion recovery acquisitions slices were acquired over a 48-mm cord segment. GM and WM were both manually segmented by 2 experienced readers and compared with an automatic variational segmentation algorithm with a shape prior modified for 3D data with a slice similarity prior. Precision and accuracy of the automatic method were evaluated using coefficients of variation and Dice similarity coefficients.

RESULTS

The mean GM area was 17.20 ± 2.28 mm² and the mean WM area was 72.71 ± 7.55 mm² using the automatic method. Reproducibility was high for both methods, while being better for the automatic approach (all mean automatic coefficients of variation, ≤4.77%; all differences, P < .001). The accuracy of the automatic method compared with the manual reference standard was excellent (mean Dice similarity coefficients: 0.86 ± 0.04 for GM and 0.90 ± 0.03 for WM). The automatic approach demonstrated similar coefficients of variation between intra- and intersession reproducibility as well as among all acquired spinal cord slices.

CONCLUSIONS

Our novel approach including the averaged magnetization inversion recovery acquisitions sequence and a fully-automated postprocessing segmentation algorithm demonstrated an accurate and reproducible spinal cord GM and WM segmentation. This pipeline is promising for both the exploration of longitudinal structural GM changes and application in clinical settings in disorders affecting the spinal cord.

Long-term prognostic impact of surgical complications in the German Rectal Cancer Trial CAO/ARO/AIO-94

Background

The influence of postoperative complications on survival in patients with locally advanced rectal cancer undergoing combined modality treatment is debatable. This study evaluated the impact of surgical complications on oncological outcomes in patients with locally advanced rectal cancer treated within the randomized CAO/ARO/AIO-94 (Working Group of Surgical Oncology/Working Group of Radiation Oncology/Working Group of Medical Oncology of the Germany Cancer Society) trial.

Methods

Patients were assigned randomly to either preoperative chemoradiotherapy (CRT) followed by total mesorectal excision (TME) or postoperative CRT between 1995 and 2002. Anastomotic leakage and wound healing disorders were evaluated prospectively, and their associations with overall survival, and distant metastasis and local recurrence rates after a long-term follow-up of more than 10 years were determined. Medical complications (such as cardiopulmonary events) were not analysed in this study.

Results

A total of 799 patients were included in the analysis. Patients who had anterior or intersphincteric resection had better 10-year overall survival than those treated with abdominoperineal resection (63·1 versus 51·3 per cent; P &lt; 0·001). Anastomotic leakage was associated with worse 10-year overall survival (51 versus 65·2 per cent; P = 0·020). Overall survival was reduced in patients with impaired wound healing (45·7 versus 62·2 per cent; P = 0·009). At 10 years after treatment, patients developing any surgical complication (anastomotic leakage and/or wound healing disorder) had impaired overall survival (46·6 versus 63·8 per cent; P &lt; 0·001), a lower distant metastasis-free survival rate (63·2 versus 72·0 per cent; P = 0·030) and more local recurrences (15·5 versus 6·4 per cent; P &lt; 0·001). In a multivariable Cox regression model, lymph node metastases (P &lt; 0·001) and surgical complications (P = 0·008) were the only independent predictors of reduced overall survival.

Conclusion

Surgical complications were associated with adverse oncological outcomes in this trial.

Gender dependent rate of metabolism of the opioid receptor-PET ligand [18F]fluoroethyldiprenorphine

Aim: The morphinane-derivate 6-O-(2-[18F]fluoroethyl)- 6-O-desmethyldiprenorphine ([18F]FDPN) is a nonselective opioid receptor ligand currently used in positron emission tomography (PET). Correction for plasma metabolites of the arterial input function is necessary for quantitative measurements of [18F]FDPN binding. A study was undertaken to investigate if there are gender dependent differences in the rate of metabolism of [18F]FDPN. Methods: The rate of metabolism of [18F]FDPN was mathematically quantified by fitting a bi-exponential function to each individual’s dynamic metabolite data. Results: No statistically significant gender differences were found for age, weight, body mass index or dose. However, significant differences (p <0.01) in two of the four kinetic parameters describing the rate of metabolism were found between the two groups, with women metabolizing [18F]FDPN faster than men. These differences were found in the contribution of the fast and slow kinetic components of the model describing the distribution of radioactive species in plasma, indicating a higher rate of enzyme-dependent degradation of [18F]FDPN in women than in men. Conclusion: The findings reinforce the need for individualized metabolite correction during [18F]FDPN-PET scans and also indicate that in certain cases, grouping according to gender could be performed in order to minimize methodological errors of the input function prior to kinetic analyses.

Effects of different endurance exercise modalities on migraine days and cerebrovascular health in episodic migraineurs: A randomized controlled trial

Aerobic exercise training is a promising complementary treatment option in migraine and can reduce migraine days and improve retinal microvascular function. Our aim was to elucidate whether different aerobic exercise programs at high vs moderate intensities distinctly affect migraine days as primary outcome and retinal vessel parameters as a secondary. In this randomized controlled trial, migraine days were recorded by a validated migraine diary in 45 migraineurs of which 36 (female: 28; age: 36 (SD:10)/BMI: 23.1 (5.3) completed the training period (dropout: 20%). Participants were assigned (Strata: age, gender, fitness and migraine symptomatology) to either high intensity interval training (HIT), moderate continuous training (MCT), or a control group (CON). Intervention groups trained twice a week over a 12-week intervention period. Static retinal vessel analysis, central retinal arteriolar (CRAE) and venular (CRVE) diameters, as well as the arteriolar-to-venular diameter ratio (AVR) were obtained for cerebrovascular health assessment. Incremental treadmill testing yielded maximal and submaximal fitness parameters. Overall, moderate migraine day reductions were observed (ηP2 = .12): HIT revealed 89% likely beneficial effects (SMD = 1.05) compared to MCT (SMD = 0.50) and CON (SMD = 0.59). Very large intervention effects on AVR improvement (ηP2 = 0.27), slightly favoring HIT (SMD=-0.43) over CON (SMD=0), were observed. HIT seems more effective for migraine day reduction and improvement of cerebrovascular health compared to MCT. Intermittent exercise programs of higher intensities may need to be considered as an additional treatment option in migraine patients.

A 1-minute full brain MR exam using a multicontrast EPI sequence

PURPOSE

A new multicontrast echo-planar imaging (EPI)-based sequence is proposed for brain MRI, which can directly generate six MR contrasts (T₁ -FLAIR, T₂ -w, diffusion-weighted (DWI), apparent diffusion coefficient (ADC), T2*-w, T₂ -FLAIR) in 1 min with full brain coverage. This could enable clinical MR clinical screening in similar time as a conventional CT exam but with more soft-tissue information.

METHODS

Eleven sequence modules were created as dynamic building blocks for the sequence. Two EPI readout modules were reused throughout the sequence and were prepended by other modules to form the desired MR contrasts. Two scan protocols were optimized with scan times of 55-75 s. Motion experiments were carried out on two volunteers to investigate the robustness against head motion. Scans on patients were carried out and compared to conventional clinical images.

RESULTS

The pulse sequence is found to be robust against motion given its single-shot nature of each contrast. For excessive out-of-plane head motion, the T₁ -FLAIR and T₂ -FLAIR contrasts suffer from incomplete inversion. Despite lower signal-to-noise ratio (SNR) and resolution, the 1-min multicontrast EPI data show promising correspondence with conventional diagnostic scans on patients.

CONCLUSION

A 1 min multicontrast brain MRI scan based on EPI readouts has been presented in this feasibility study. Preliminary data show potential for clinical brain MRI use with minimal bore time for the patient. Such short examination time could be useful (e.g., for screening and acute stroke). The sequence may also help planning conventional brain MRI scans if run at the beginning of an examination. Magn Reson Med 79:3045-3054, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Model-based denoising in diffusion-weighted imaging using generalized spherical deconvolution

PURPOSE

Diffusion MRI often suffers from low signal-to-noise ratio, especially for high b-values. This work proposes a model-based denoising technique to address this limitation.

METHODS

A generalization of the multi-shell spherical deconvolution model using a Richardson-Lucy algorithm is applied to noisy data. The reconstructed coefficients are then used in the forward model to compute denoised diffusion-weighted images (DWIs). The proposed method operates in the diffusion space and thus is complementary to image-based denoising methods.

RESULTS

We demonstrate improved image quality on the DWIs themselves, maps of neurite orientation dispersion and density imaging, and diffusional kurtosis imaging (DKI), as well as reduced spurious peaks in deterministic tractography. For DKI in particular, we observe up to 50% error reduction and demonstrate high image quality using just 30 DWIs. This corresponds to greater than fourfold reduction in scan time if compared to the widely used 140-DWI acquisitions. We also confirm consistent performance in pathological data sets, namely in white matter lesions of a multiple sclerosis patient.

CONCLUSION

The proposed denoising technique termed generalized spherical deconvolution has the potential of significantly improving image quality in diffusion MRI. Magn Reson Med 78:2428-2438, 2017. © 2017 International Society for Magnetic Resonance in Medicine.

Altered Metabolism in Frontal Brain Circuits in Cluster Headache

Neuroimaging studies have explored cerebral activation patterns in patients with cluster headache (CH) during attacks and have revealed activation of multiple brain areas known to belong to the general pain-processing network. However, it is still unclear which changes in brain metabolism are inherent to the shift from the ‘in bout’ to the ‘out of bout’ period. We measured cerebral glucose metabolism in 11 episodic CH patients during the cluster and again during the remission period with 18F-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) and compared these data with 11 healthy controls. ‘In bout’ compared with ‘out of bout’ scans were associated with increases of metabolism in the perigenual anterior cingulate cortex (ACC), posterior cingulate cortex, prefrontal cortex, insula, thalamus and temporal cortex. Decreases in metabolism were observed in the cerebellopontine area. Compared with healthy volunteers, hypometabolism in the patient group (‘in bout’ and ‘out of bout’) was found in the perigenual ACC, prefrontal and orbitofrontal cortex. Thus, FDG-PET in CH patients revealed ‘in bout’ activation of brain structures which are involved in descending pain control. Compared with controls, the regional brain metabolism was constitutively decreased in most of these structures, irrespective of the bout. This finding indicates a deficient top-down modulation of antinociceptive circuits in CH patients. We suggest that trigger mechanisms of CH are insufficiently controlled and thus promote the initiation of the bout period and acute attack.

Daclizumab high-yield process reduced the evolution of new gadolinium-enhancing lesions to T1 black holes in patients with relapsing-remitting multiple sclerosis

BACKGROUND AND PURPOSE

In the SELECT study, treatment with daclizumab high-yield process (DAC HYP) versus placebo reduced the frequency of gadolinium-enhancing (Gd(+) ) lesions in patients with relapsing-remitting multiple sclerosis (RRMS). The objective of this post hoc analysis of SELECT was to evaluate the effect of DAC HYP on the evolution of new Gd(+) lesions to T1 hypointense lesions (T1 black holes).

METHODS

SELECT was a randomized double-blind study of subcutaneous DAC HYP 150 or 300 mg or placebo every 4 weeks. Magnetic resonance imaging (MRI) scans were performed at baseline and weeks 24, 36 and 52 in all patients and monthly between weeks 4 and 20 in a subset of patients. MRI scans were evaluated for new Gd(+) lesions that evolved to T1 black holes at week 52. Data for the DAC HYP groups were pooled for analysis.

RESULTS

Daclizumab high-yield process reduced the number of new Gd(+) lesions present at week 24 (P = 0.005) or between weeks 4 and 20 (P = 0.014) that evolved into T1 black holes at week 52 versus placebo. DAC HYP treatment also reduced the percentage of patients with Gd(+) lesions evolving to T1 black holes versus placebo.

CONCLUSIONS

Treatment with DAC HYP reduced the evolution of Gd(+) lesions to T1 black holes versus placebo, suggesting that inflammatory lesions that evolved during DAC HYP treatment are less destructive than those evolving during placebo treatment.

Hypothalamic Activation in Trigeminal Autonomic Cephalgia: Functional Imaging of an Atypical Case

We report headache induced BOLD changes in an atypical case of trigeminal autonomic cephalgia (TAC). A 68-year-old patient was imaged using fMRi during three attacks of a periorbital head-pain with a average duration of 3 min. During the attacks, left sided conjunctival injection, rhinorrhea, lacrimation, facial sweating and hypersalivation were apparent. These attacks were usually partly responsive to oxygen administration but otherwise refractory to any drug. The patient described either attacks with a duration of one minute or less or longer attacks persisting for maximum of 20 min with headaches occurring up to 100 times a day. When considering the symptoms, frequency, duration and therapeutic response of the patient's headache, no clear-cut classification to one of the subtypes of trigeminal autonomic cephalgias (cluster headache, paroxysmal hemicrania, SUNCT) or trigeminal neuralgia was possible. The cerebral activation pattern was similar but not identical to those previously observed in cluster headache and SUNCT with a prominent activation in the hypothalamic grey matter. This case study underlines the conceptual value of the term TAC for the group of headaches focusing around the trigeminal-autonomic reflex. Our results emphasize the importance of the hypothalamus as key region in the pathophysiology of this entity.

[Lymph node metastases in ypT1/2 rectal cancer after neoadjuvant chemoradiotherapy : The Achilles heel of organ-preserving operative procedures?]

BACKGROUND

For patients with rectal cancer and complete remission (ypT0) or with good response and residual tumor restricted only to the bowel wall (ypT1-2) after neoadjuvant chemoradiotherapy (CRT), local excision has been suggested as an alternative to avoid the significant morbidity and functional deficits associated with total mesorectal excision (TME). The aim of this investigation was to investigate the incidence, distribution and tumor-related localization of mesorectal lymph node (LN) metastases in TME specimens with complete remission (ypT0), intramural (ypT1-2) and extramural (ypT3-4) residual tumor tissue.

PATIENTS AND METHODS

Specimens of TME from 81 patients with locally advanced rectal cancer (UICC II-III) undergoing neoadjuvant CRT within the phase III German rectal cancer trial CAO/ARO/AIO-04 were prospectively evaluated. The entire mesorectal compartment was microscopically screened after complete paraffin embedding. The number and localization of all detectable LN metastases were documented in relation to the primary tumor.

RESULTS

Whereas 50 patients (62 %) had ypT3-4 rectal cancer after neoadjuvant CRT, 20 patients (25 %) presented with residual tumor within the bowel wall (ypT1-2), 11 patients (14 %) had pathological complete remission (ypT0), an average of 28 ± 13.7 LN were detected per specimen and 25 patients (31 %) had residual LN metastases after CRT. Although the incidence of LN metastases was higher in the ypT3-4 group (40 %), 25 % of patients in the ypT1-2 group with intramural residual tumor had a mean number of 2.2 residual LN metastases of which 55 % were located far from the primary lesion in the proximal mesorectum. None of the patients with ypT0 status (complete response) had residual LN metastases.

CONCLUSION

Even in patients with good response and post-CRT tumor tissue restricted only to the bowel wall (ypT1-2), there is still a considerable risk for residual LN metastases. Local excision of residual rectal cancer was accompanied by a higher rate of local failure and radical surgery with TME should remain the standard treatment in these patients. To date, valid selection criteria for patients eligible for organ-sparing surgery are still lacking.

Diffusion in realistic biophysical systems can lead to aliasing effects in diffusion spectrum imaging

PURPOSE

Diffusion spectrum imaging (DSI) is an imaging technique that has been successfully applied to resolve white matter crossings in the human brain. However, its accuracy in complex microstructure environments has not been well characterized.

THEORY AND METHODS

Here we have simulated different tissue configurations, sampling schemes, and processing steps to evaluate DSI performances' under realistic biophysical conditions. A novel approach to compute the orientation distribution function (ODF) has also been developed to include biophysical constraints, namely integration ranges compatible with axial fiber diffusivities.

RESULTS

Performed simulations identified several DSI configurations that consistently show aliasing artifacts caused by fast diffusion components for both isotropic diffusion and fiber configurations. The proposed method for ODF computation showed some improvement in reducing such artifacts and improving the ability to resolve crossings, while keeping the quantitative nature of the ODF.

CONCLUSION

In this study, we identified an important limitation of current DSI implementations, specifically the presence of aliasing due to fast diffusion components like those from pathological tissues, which are not well characterized, and can lead to artifactual fiber reconstructions. To minimize this issue, a new way of computing the ODF was introduced, which removes most of these artifacts and offers improved angular resolution. Magn Reson Med 76:1837-1847, 2016. © 2015 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

The association between olfactory bulb volume, cognitive dysfunction, physical disability and depression in multiple sclerosis

BACKGROUND AND PURPOSE

Olfactory bulb atrophy is associated with cognitive dysfunction in Parkinson's and Alzheimer's disease, and with major depression. It has been suggested that olfactory bulb atrophy or dysfunction is therefore a marker of neurodegeneration. Multiple sclerosis (MS) is now also recognized as having a significant neurodegenerative component. Thus, the aim of this study was to investigate associations between physical and cognitive disability, depression and olfactory bulb volume in MS.

METHODS

In total, 146 patients with MS (mean age 49.0 ± 10.9 years, disease duration 21.2 ± 9.3 years, median Expanded Disability Status Scale (EDSS) score 3.0 (range 0-7.5), 103 relapsing-remitting, 35 secondary progressive and eight primary progressive MS) underwent a standardized neurological examination, comprehensive neuropsychological testing and magnetic resonance imaging (MRI); data of 27 healthy people served as age- and gender-matched control subjects. The olfactory bulb was semi-automatically segmented on high-resolution three-dimensional T1-weighted MRI.

RESULTS

Mean olfactory bulb volume was lower in MS patients than healthy controls (183.9 ± 40.1 vs. 209.2 ± 59.3 μl; P = 0.018 adjusted to intracranial volume). Olfactory bulb volume was similar across clinical disease subtypes and did not correlate with cognitive performance, EDSS scores or total proton density/T2 white matter lesion volume. However, in progressive MS, the mean olfactory bulb volume correlated with depression scores (Spearman's rho = -0.38, P < 0.05) confirmed using a multivariate linear regression analysis including cognitive fatigue scores. This association was not observed in relapsing-remitting MS.

CONCLUSION

Olfactory bulb volume was lower in MS than in healthy controls. Olfactory bulb volume does not seem to mirror cognitive impairment in MS; however, it is associated with higher depression scores in progressive MS.

PARTIAL INDEPENDENCE OF FINGOLIMOD EFFECT ON DIFFUSE VS. FOCAL DAMAGE

Objective

To investigate if the effects of fingolimod 0.5mg on brain volume loss are mediated through effects on focal disease activity (FD) or independent-reduction of diffuse damage (DD).

Methods

FREEDOMS and FREEDOMS-II data was pooled and analyzed post-hoc. Assessment of the percent brain volume change (PBVC) at M12 and 24, in patients with no evidence of FD, (absence of new Gd+ T1-lesions and/or new/enlarging T2-lesions) and clinical relapses. Regression analysis of the intent-to-treat (ITT) population to quantified whether the extent of the treatment effect was maintained for patients with new/active lesions and relapses

Results

Of the 1383 patients included, 808 patients (placebo=142; fingolimod=666) showed no FD at M12 and 573 patients (placebo=79; fingolimod=494) at M24 showed no FD. Fingolimod significantly reduced PBVC by 52% and 42% vs. placebo, over 12M and 24M respectively. In the pooled ITT population, fingolimod reduced 49% of PBVC (p<0.001)vs placebo over 24M. This effect was still evident when adjusting for new-active lesions and relapse activity (28% reduction vs placebo, p<0.001). The regression model suggests 57% of fingolimod effect on PBVC is FD-independent. Fingolimod effect on DD is partly independent of its treatment effect on FD, suggesting fingolimod impacts both inflammatory and neurodegenerative components.

Genetic associations with brain cortical thickness in multiple sclerosis

Multiple sclerosis (MS) is characterized by temporal and spatial dissemination of demyelinating lesions in the central nervous system. Associated neurodegenerative changes contributing to disability have been recognized even at early disease stages. Recent studies show the importance of gray matter damage for the accrual of clinical disability rather than white matter where demyelination is easily visualized by magnetic resonance imaging (MRI). The susceptibility to MS is influenced by genetic risk, but genetic factors associated with the disability are not known. We used MRI data to determine cortical thickness in 557 MS cases and 75 controls and in another cohort of 219 cases. We identified nine areas showing different thickness between cases and controls (regions of interest, ROI) (eight of them were negatively correlated with Kurtzke's expanded disability status scale, EDSS) and conducted genome-wide association studies (GWAS) in 464 and 211 cases available from the two data sets. No marker exceeded genome-wide significance in the discovery cohort. We next combined nominal statistical evidence of association with physical evidence of interaction from a curated human protein interaction network, and searched for subnetworks enriched with nominally associated genes and for commonalities between the two data sets. This network-based pathway analysis of GWAS detected gene sets involved in glutamate signaling, neural development and an adjustment of intracellular calcium concentration. We report here for the first time gene sets associated with cortical thinning of MS. These genes are potentially correlated with disability of MS.

Fingolimod effect on brain volume loss independently contributes to its effect on disability

Background:

Brain volume loss occurs in patients with relapsing–remitting MS. Fingolimod reduced brain volume loss in three phase 3 studies.

Objective:

To evaluate whether the effect of fingolimod on disability progression was mediated by its effects on MRI lesions, relapses or brain volume loss, and the extent of this effect.

Methods:

Patients (992/1272; 78%) from the FTY720 Research Evaluating Effects of Daily Oral Therapy in Multiple Sclerosis (FREEDOMS) study were analyzed. Month-24 percentage brain volume change, month-12 MRI-active lesions and relapse were assessed. The Prentice criteria were used to test surrogate marker validity. The proportion of treatment effect on disability progression explained by each marker was calculated.

Results:

Two-year disability progression was associated with active T2 lesions (OR = 1.24; p = 0.001) and more relapses during year 1 (OR = 2.90; p < 0.001) and lower percentage brain volume change over two years (OR = 0.78; p < 0.001). Treatment effect on active T2 lesions, relapses and percentage brain volume change explained 46%, 60% and 23% of the fingolimod effect on disability. Multivariate analysis showed the number of relapses during year 1 (OR = 2.62; p < 0.001) and yearly percentage brain volume change over two years (OR = 0.85; p = 0.009) were independent predictors of disability progression, together explaining 73% of fingolimod effect on disability.

Conclusions:

The treatment effect on relapses and, to a lesser extent, brain volume loss were both predictors of treatment effect on disability; combining these predictors better explained the effect on disability than either factor alone.

Clinical characteristics of pain in patients with pituitary adenomas

OBJECTIVE

Clinical presentation of pituitary adenomas frequently involves pain, particularly headache, due to structural and functional properties of the tumour. Our aim was to investigate the clinical characteristics of pain in a large cohort of patients with pituitary disease.

DESIGN

In a cross-sectional study, we assessed 278 patients with pituitary disease (n=81 acromegaly; n=45 Cushing's disease; n=92 prolactinoma; n=60 non-functioning pituitary adenoma).

METHODS

Pain was studied using validated questionnaires to screen for nociceptive vs neuropathic pain components (painDETECT), determine pain severity, quality, duration and location (German pain questionnaire) and to assess the impact of pain on disability (migraine disability assessment, MIDAS) and quality of life (QoL).

RESULTS

We recorded a high prevalence of bodily pain (n=180, 65%) and headache (n=178, 64%); adrenocorticotropic adenomas were most frequently associated with pain (n=34, 76%). Headache was equally frequent in patients with macro- and microadenomas (68 vs 60%; P=0.266). According to painDETECT, the majority of the patients had a nociceptive pain component (n=193, 80%). Despite high prevalence of headache, 72% reported little or no headache-related disability (MIDAS). Modifiable factors including tumour size, genetic predisposition, previous surgery, irradiation or medical therapy did not have significant impact neither on neuropathic pain components (painDETECT) nor on headache-related disability (MIDAS). Neuropathic pain and pain-related disability correlated significantly with depression and impaired QoL.

CONCLUSIONS

Pain appears to be a frequent problem in pituitary disease. The data suggest that pain should be integrated in the diagnostic and therapeutic work-up of patients with pituitary disease in order to treat them appropriately and improve their QoL.

Photic hypersensitivity in the premonitory phase of migraine--a positron emission tomography study

BACKGROUND AND PURPOSE

Sensitivity to light (photophobia) is a common ill-understood symptom of migraine, whose neurobiology is important in understanding the disorder.

METHODS

Patients reporting premonitory symptoms before migraine headache were infused with nitroglycerin (GTN) at a first visit. Patients who responded with premonitory symptoms followed by a delayed headache resembling their migraine had positron emission tomography (PET) scans at least 1 week later, during which GTN infusion was repeated. H2 (15) O PET scans were performed during baseline (pain free), premonitory phase (pain free) and migraine headache. Patients were divided into two groups, with and without photophobia in the premonitory phase. The differences between the premonitory and baseline scans were analysed within groups and between groups using statistical parametric mapping.

RESULTS

Thirteen patients participated in the PET study, 10 of whom had at least one PET scan during the premonitory phase in the absence of pain. Data from these 10 patients were included in the final analysis. Five patients had photophobia and five patients did not have photophobia in the premonitory phase. Comparing the premonitory scans to baseline scans, there was activation of extrastriate visual cortex (BA18) in patients with photophobia. This activation was significantly greater than in the patients without photophobia.

CONCLUSION

Our findings indicate that photic hypersensitivity is linked to activation of the visual cortex during the premonitory phase of migraine in the absence of headache.

Discrepancies between medical oncologists and surgeons in assessment of resectability and indication for chemotherapy in patients with colorectal liver metastases

BACKGROUND

Multidisciplinary discussion of the treatment of patients with colorectal liver metastases (CRLM) is advocated currently. The aim of this study was to investigate medical oncologists' and surgeons' assessment of resectability and indication for chemotherapy, and the effect of an educational intervention on such assessment.

METHODS

Medical histories of 30 patients with CRLM were presented to ten experienced medical oncologists and 11 surgeons at an initial virtual tumour board meeting (TB1). Treatment recommendations were obtained from each participant by voting for standardized answers. Following lectures on the potential of chemotherapy and surgery, assessment was repeated at a second virtual tumour board meeting (TB2), using the same patients and participants.

RESULTS

Overall, 630 answers (21 × 30) were obtained per tumour board meeting. At TB1, resectability was expected more frequently by surgeons. Participants changed 56·8 per cent of their individual answers at TB2. Assessment shifted from potentially resectable to resectable CRLM in 81 of 161 and from unresectable to (potentially) resectable CRLM in 29 of 36 answers. Preoperative chemotherapy was indicated more often by medical oncologists, and overall was included in 260 answers (41·3 per cent) at TB1, compared with only 171 answers (27·1 per cent) at TB2. Medical oncologists more often changed their decision to primary resection in resectable patients (P = 0·006). Postoperative chemotherapy was included in 51·9 and 52·4 per cent of all answers at TB1 and TB2 respectively, with no difference in changes between medical oncologists and surgeons (P = 0·980).

CONCLUSION

Resectability and indication for preoperative chemotherapy were assessed differently by medical oncologists and surgeons. The educational intervention resulted in more patients deemed resectable by both oncologists and surgeons, and less frequent indication for chemotherapy.

Comparing propofol versus sevoflurane anesthesia for epileptogenic focus detection during positron emission tomography in pediatric patients

BACKGROUND

Fluoro-D-deoxyglucose positron emission tomography (FDG-PET) is a standard procedure for interictal assessment and accurate pre-surgical evaluation of presumed epileptogenic zone localization. Profound sedation or general anesthesia is frequently required to reduce movement artefacts in young or cognitively impaired patients during image acquisition. This study compares the impact of propofol and sevoflurane anesthesia on overall quality of PET images, detectability of a hypometabolic lesion and demarcation of the detected lesion in pediatric patients suffering from focal epilepsia.

METHODS

Pediatric patients with focal epilepsia were anesthesized using propofol (N.=37) or sevoflurane (N.=43). Two independent blinded investigators rated the PET-scans on a 3-point Likert scale with respect to overall quality of PET images, detectability of a hypometabolic lesion and demarcation of the detected lesion. Mann-Whitney-U-Test was conducted to compare the rating results between the two anesthesia regimes. Inter-rater reliability was calculated using Cohen's Kappa.

RESULTS

Anesthesia was throughout uneventful and there was no clinical evidence for peridiagnostic seizures. Differences in neither single dimension ratings nor in sum scores (mean 5.8 ± SD 1.5 for propofol, and 5.7 ± SD 1.5 for sevoflurane; P=0.567) were statistically significant. Cohen's Kappa was between 0.428 and 0.499.

CONCLUSION

For surgical planning in patients with epilepsy, FDG-PET imaging is an indispensable functional imaging technique to detect hypometabolism. We conclude that both, sevoflurane and propofol based anesthetic regimes are suitable to detect hypometabolic cerebral lesions during FDG-PET.

Magnetic resonance imaging correlates of physical disability in relapse onset multiple sclerosis of long disease duration

Background:

Understanding long-term disability in multiple sclerosis (MS) is a key goal of research; it is relevant to how we monitor and treat the disease.

Objectives:

The Magnetic Imaging in MS (MAGNIMS) collaborative group sought to determine the relationship of brain lesion load, and brain and spinal cord atrophy, with physical disability in patients with long-established MS.

Methods:

Patients had a magnetic resonance imaging (MRI) scan of their brain and spinal cord, from which we determined brain grey (GMF) and white matter (WMF) fractional volumes, upper cervical spinal cord cross-sectional area (UCCA) and brain T2-lesion volume (T2LV). We assessed patient disability using the Expanded Disability Status Scale (EDSS). We analysed associations between EDSS and MRI measures, using two regression models (dividing cohort by EDSS into two and four sub-groups).

Results:

In the binary model, UCCA (p < 0.01) and T2LV (p = 0.02) were independently associated with the requirement of a walking aid. In the four-category model UCCA (p < 0.01), T2LV (p = 0.02) and GMF (p = 0.04) were independently associated with disability.

Conclusions:

Long-term physical disability was independently linked with atrophy of the spinal cord and brain T2 lesion load, and less consistently, with brain grey matter atrophy. Combinations of spinal cord and brain MRI measures may be required to capture clinically-relevant information in people with MS of long disease duration.