Weighted Spin Echo Research Articles

Targeted MRI (tMRI) of Small Increases in the T<sub>1</sub> of Normal Appearing White Matter in Mild Traumatic Brain Injury (mTBI) Using a Divided Subtracted Inversion Recovery (dSIR) Sequence

In modelling studies targeted MRI (tMRI) of small increases in the T<sub>1</sub> of tissues using divided Subtracted Inversion Recovery (dSIR) sequences show ten or more times the contrast seen with conventional IR sequences. This may be particularly useful in imaging normal appearing white matter where there may be small changes in T<sub>1</sub> and/or T<sub>2</sub> in disease but these changes may be insufficient to produce useful contrast with conventional T<sub>2</sub>-weighted spin echo (T<sub>2</sub>-wSE) and T<sub>2</sub>-FLuid Attenuated Inversion Recovery (T<sub>2</sub>-FLAIR) sequences. In a case of recurrent mild Traumatic Brain Injury (mTBI), very extensive high contrast abnormalities were seen in white matter using a dSIR sequence that targeted small increases in T<sub>1</sub> in areas where no abnormality was apparent with T<sub>2</sub>-wSE or T<sub>2</sub>-FLAIR sequences. The increases in T<sub>1</sub> may be due to neuroinflammation and/or degeneration which produces the abnormalities seen on the dSIR images. tMRI of normal appearing white matter may have widespread application in clinical MRI of the brain.

Volumetric T2 -weighted spin echo imaging with improved SNR using localized quadratic encoding and a spiral readout trajectory.

To demonstrate T2 -weighted (single-echo) spin-echo (SE) imaging with near-optimal acquisition efficiency by applying SNR-efficient RF slice encoding and spiral readout. A quadratic-phase (frequency swept) excitation RF pulse replaced the conventional excitation in T2 -weighted SE sequence to excite a thick slab that is internally spatially encoded by a variable phase along the slice direction. Highly overlapping slabs centered at every desired slice location were acquired in multiple passes, such that the entire imaging volume was excited by contiguous slabs in any given pass. Following 90° excitation, each slab was refocused with a conventional 180° RF to produce a SE signal, followed by a spiral in-out readout. A noise-insensitive reconstruction removed the quadratic phase in the spatial frequency domain, yielding desired slice resolution and improved SNR. Increasing the RF frequency sweep (hence, excitation width) allowed more frequent encoding of each slice over the multiple passes, improving final image SNR, until crosstalk ensued at excessive slab widths compared to their center-to-center spacing. With an optimized slab width, the proposed technique used all passes to acquire every prescribed slice, with substantially improved SNR over conventional SE or 2D-turbo-spin-echo (TSE) scans. Quantitative SNR measurements indicated similar SNR as 3D-TSE, but radiologist scoring favored 3D-TSE, mainly because of spiral-related artifacts and possibly because of regularized reconstructions in 3D-TSE. Using SNR-efficient slice excitation scheme and spiral readout helped eliminate SNR and temporal inefficiencies in conventional T2 -weighted imaging, yielding SNR independent of TR or number of passes.

Simultaneous T2 -weighted real-time MRI of two orthogonalslices.

MR guidance is used during therapy to detect and compensate for lesion motion. T2 -weighted MRI often has a superior lesion contrast in comparison to T1 -weighted real-time imaging. The purpose of this work was to design a fast T2 -weighted sequence capable of simultaneously acquiring two orthogonal slices, enabling real-time tracking of lesions. To generate a T2 contrast in two orthogonal slices simultaneously, a sequence (Ortho-SFFP-Echo) was designed that samples the T2 -weighted spin echo (S- ) signal in a TR-interleaved acquisition of two slices. Slice selection and phase-encoding directions are swapped between the slices, leading to a unique set of spin-echo signal conditions. To minimize motion-related signal dephasing, additional flow-compensation strategies are implemented. In both the abdominal breathing phantom and in vivo experiments, a time series was acquired using Ortho-SSFP-Echo. The centroid of the target was tracked in postprocessing steps. In the phantom, the lesion could be identified and delineated in the dynamic images. In the volunteer experiments, the kidney was visualized with a T2 contrast at a temporal resolution of 0.45 s under free-breathing conditions. A respiratory belt demonstrated a strong correlation with the time course of the kidney centroid in the head-foot direction. A hypointense saturation band at the slice overlap did not inhibit lesion tracking in the semi-automatic postprocessing steps. The Ortho-SFFP-Echo sequence delivers real-time images with a T2 -weighted contrast in two orthogonal slices. The sequence allows for simultaneous acquisition, which could be beneficial for real-time motion tracking in radiotherapy or interventional MRI.

Three-Dimensional Bioprinted MR-Trackable Regenerative Scaffold for Postimplantation Monitoring on T1-Weighted MRI.

A three-dimensional (3D) bioprinted tissue scaffold is a promising therapeutic that goes beyond providing physical support for tissue regeneration by enabling precise spatial control over scaffold geometry and integration of different materials/cells. Critically important is in vivo confirmation of correct scaffold placement and retention during the initial 24hours postimplantation, to detect unwanted implant migration. To incorporate a safe, efficient MR contrast agent into a bioprinting workflow, and to achieve bright-contrast scaffold monitoring in vivo postimplantation. In vitro and animal in vivo longitudinal study. Two female Sprague Dawley rats (~200 g) for labeled and unlabeled scaffold implantation in the subcutaneous dorsal space flanking the vertebral column. A 7.0 T/T1 -weighted spin echo (SE) sequence and T1 mapping using turbo SE with variable repetition times (TRs). Cell viability and proliferation were assessed over 2 weeks after labeling bioprinted gelatin/alginate scaffolds with MnPNH2 (0.5 mM, 24hours). In vitro MRI was performed 0, 12, and 24hours postlabeling in nine labeled and three unlabeled (control) scaffolds to monitor T1 evolution. In vivo MRI was performed immediately and 24hours postimplantation to assess T1 . Acute inflammation near surgical site was monitored in one rat to 3 days. One-way analysis of variance with Tukey-Kramer post hoc analysis (P < 0.01). Cell viability was unaffected by bioprinting/labeling: viability exceeded 90% in all scaffolds after 1 week. In vitro T1 's were significantly lower in labeled scaffolds compared to control (207 msec vs. 2257 msec) immediately postlabeling and 24hours later (1227 msec vs. 2257 msec). In vivo T1 's were significantly different (243.6msec vs. 2414.6msec) immediately postimplantation, and no differences emerged compared to respective in vitro control/labeled counterparts. The 24-hours imaging and gross pathology confirmed migration of scaffolds beyond the imaging field. We report an MR-detectable, cell-compatible bioprinted scaffold, utilizing a T1 -weighting contrast agent for high-resolution, postimplantation scaffold tracking. 2 TECHNICAL EFFICACY: Stage 1.

GdDO3NI Enhanced Magnetic Resonance Imaging Allows Imaging of Hypoxia After Brain Injury.

Brain tissue hypoxia is a common consequence of traumatic brain injury (TBI) due to the rupture of blood vessels during impact and it correlates with poor outcome. The current magnetic resonance imaging (MRI) techniques are unable to provide a direct map of tissue hypoxia. To investigate whether GdDO3NI, a nitroimidazole-based T1 MRI contrast agent allows imaging hypoxia in the injured brain after experimental TBI. Prospective. TBI-induced mice (controlled cortical impact model) were intravenously injected with either conventional T1 agent (gadoteridol) or GdDO3NI at 0.3 mmol/kg dose (n=5 for each cohort) along with pimonidazole (60 mg/kg) at 1 hour postinjury and imaged for 3 hours following which they were euthanized. 7 T/T2 -weighted spin echo and T1 -weighted gradient echo. Injured animals were imaged with T2 -weighted spin-echo sequence to estimate the extent of the injury. The mice were then imaged precontrast and postcontrast using a T1 -weighted gradient-echo sequence for 3 hours postcontrast. Regions of interests were drawn on the brain injury region, the contralateral brain as well as on the cheek muscle region for comparison of contrast kinetics. Brains were harvested immediately post-imaging for immunohistochemical analysis. One-way analysis of variance and two-sample t-tests were performed with a P< 0.05 was considered statistically significant. GdDO3NI retention in the injury region at 2.5-3 hours post-injection was significantly higher compared to gadoteridol (mean retention fraction 63.95% ± 27.43% vs. 20.68% ± 7.43% for gadoteridol at 3 hours) while it rapidly cleared out of the muscle region. Pimonidazole staining confirmed the presence of hypoxia in both gadoteridol and GdDO3NI cohorts, and the later cohort showed good agreement with MRI contrast enhancement. GdDO3NI was successfully shown to visualize hypoxia in the brain post-TBI using T1 -weighted MRI at 2.5-3 hours postcontrast. 1 TECHNICAL EFFICACY: Stage 1.

Technical Note: Four-dimensional deformable digital phantom for MRI sequence development.

MR-guided radiotherapy has different requirements for the images than diagnostic radiology, thus requiring development of novel imaging sequences. MRI simulation is an excellent tool for optimizing these new sequences; however, currently available software does not provide all the necessary features. In this paper, we present a digital framework for testing MRI sequences that incorporates anatomical structure, respiratory motion, and realistic presentation of MR physics. The extended Cardiac-Torso (XCAT) software was used to create T1 , T2 , and proton density maps that formed the anatomical structure of the phantom. Respiratory motion model was based on the XCAT deformation vector fields, modified to create a motion model driven by a respiration signal. MRI simulation was carried out with JEMRIS, an open source Bloch simulator. We developed an extension for JEMRIS, which calculates the motion of each spin independently, allowing for deformable motion. The performance of the framework was demonstrated through simulating the acquisition of a two-dimensional (2D) cine and demonstrating expected motion ghosts from T2 weighted spin echo acquisitions with different respiratory patterns. All simulations were consistent with behavior previously described in literature. Simulations with deformable motion were not more time consuming than with rigid motion. We present a deformable four-dimensional (4D) digital phantom framework for MR sequence development. The framework incorporates anatomical structure, realistic breathing patterns, deformable motion, and Bloch simulation to achieve accurate simulation of MRI. This method is particularly relevant for testing novel imaging sequences for the purpose of MR-guided radiotherapy in lungs and abdomen.

Automated Grading of Lumbar Disc Degeneration Using a Push-Pull Regularization Network Based on MRI.

Lower back pain is one of the most widely experienced health problems and is strongly associated with intervertebral disc (IVD) degeneration. The quantification of the degeneration is valuable for estimation of the material properties of the IVDs and then to perform biomechanical simulation of the spinal conditions and treatments. The MR image characteristics of relatively high intraclass variability and small interclass differences pose challenges for the classification algorithm to perform automatic grading of degenerated IVD. To assess the feasibility and improvement of a computer-assisted IVD degeneration grading method based on proposed push-pull regularization (PPR) strategy. Retrospective. In total, 500 subjects (350 for training, 70 for validation, and 80 for test in a 10-time 10-fold cross validation setting) with varied lumbar disorders were included. 3.0T; T2 -weighted spin echo sequence. IVD degeneration grading was taken as a classification task of five classes according to the Pfirrmann grading system in this study. The classification results of deep-learning models with and without PPR were compared with the classifications made by three experienced spinal radiologists. Paired t-tests. The classification results show that in four classical CNN models of VGG-M, VGG-16, GoogleNet, and ResNet-34, by embedding a PPR strategy, the accuracies of grade II and III IVD classification were improved by more than 10% (P < 0.05), and that the overall accuracy (grades I to V) was improved by over 8% (P < 0.05). The embedded PPR significantly improved the classification performance, which enhanced CNN representation capability for IVD degeneration grading. 3 TECHNICAL EFFICACY STAGE: 1.

Thalamic Nuclei Volumes and Their Relationships to Neuroperformance in Multiple Sclerosis: A Cross-Sectional Structural MRI Study.

Although reduced thalamic volume is associated with multiple sclerosis (MS)-related clinical impairment, the role of individual thalamic nuclei remains poorly understood. To test whether individual thalamic nuclei volumes are more strongly associated with clinical disability than the whole thalamic volume. Retrospective analysis of a prospective dataset. A total of 108 MS patients and 48 age- and sex-matched healthy controls (HCs) FIELD STRENGTH: 3T. 3D T1 -weighted inversion recovery spoiled gradient echo; 2D T2 -weighted fluid-attenuated inversion recovery spin echo; 2D dual-echo proton density-weighted/T2 -weighted spin echo. Clinical assessments included the Expanded Disability Status Scale (EDSS), Nine-Hole Peg Test (9HPT), Timed 25-Foot Walk (T25FW), Symbol Digit Modalities Test (SDMT), Brief Visuospatial Memory Test-Revised (BVMTR), and the California Verbal Learning Test (CVLT2). FreeSurfer provided anterior, intralaminar, lateral, medial, ventral, posterior, and total volumes. False discovery rate-corrected partial correlations (controlling for age, sex, and education) to assess the relationships between volumes and neuroperformance. Compared to HCs, MS patients presented with lower thalamic nuclei volumes (P < 0.05) except for the intralaminar nucleus (P = 0.279) and scored worse on all neuroperformance scales (P ≤ 0.05) except for CVLT2 (P = 0.151). All nuclei except intralaminar were associated with EDSS (correlation coefficient range: -0.233 to -0.395), SDMT (range: 0.247-0.423), and 9HPT (range: -0.232 to -0.303) (all P < 0.05). BVMTR was associated with anterior (r = 0.319), lateral (r = 0.31), and medial (r = 0.304) volumes (all P < 0.05). T25FW correlated with ventral (r = -0.392) and total (r = -0.309) volumes (both P < 0.05), with the latter being significantly greater (P < 0.05). Assessing individual nuclei volume can aid in unraveling the relationship between thalamic pathology and disparate aspects of MS-related disability. 2 TECHNICAL EFFICACY STAGE: 2.

P1332 Breaking the dichotomy of myocardial infarction and stress cardiomyopathy

Abstract INTRODUCTION An 83-year-old woman with a past medical history of hypertension, dyslipidaemia and recent diagnosis of disseminated breast cancer was admitted at Emergency department for acute heart failure. She complained about short chest pain episodes on previous days, the ECG showed new T negative waves on precordial leads and high sensitive troponin serum levels were modestly increased (TropT 1200ng/l). Echocardiographic assessment documented moderate left ventricular dysfunction (LVEF 40%) with apical and midventricular dyskinesia associated with hypercontractility off basal segments. The following day the patient underwent a coronary angiography that showed an occlusion in the distal segment of a large obtuse marginal branch (Panel A) with no other significant stenosis in the remaining vessels. Ventriculography showed a typical apical ballooning pattern (Panel B). Despite the occluded coronary artery was reaching the apex, the myocardial wall motion abnormalities extended beyond the ischemic territory. Therefore, a cardiac magnetic resonance (CMR) was performed a few days later in order to clarify the diagnosis. CMR confirmed the mid LVEF dysfunction with apical dyskinesia and the T2 weighted spin echo images showed myocardial oedema in all the apical segments (Panel C). Remarkably, a subedocardial late gadolinium enhancement (LGE) restricted to the apical segment of the inferolateral wall was detected, being consistent with the ischaemic territory of the occluded obtuse marginal branch (Panel D). These findings supported the concomitant diagnosis of an apical stress cardiomyopathy and an acute inferolateral myocardial infarction. The patient was successfully discharged one week later with a normal LVEF and no signs of congestion. DISCUSSION Apical ballooning in the scenario of an acute coronary syndrome may be secondary to both an acute coronary artery occlusion or to stress cardiomyopathy. Cardiac MR has a key role to resolve the differential diagnosis of these two aetiologies, since ischemia typically produces a subendocardial late gadolinium enhancement pattern and stress cardiomyopathy shows an apical oedema without coronary stenosis or extending beyond a localized ischemic territory. Our case is astonishing because in the clinical practice these two diagnoses frequently excludes each other, but as demonstrated in our case, the differential diagnosis between myocardial infarction and stress cardiomyopathy is not a proper dichotomy. Abstract P1332 Figure

Comparison of Maximum Signal Intensity of Magnevist Contrast Agent in Modified T1 Weighted Spin Echo, T1 Weighted Fast Spin Echo and T1 Weighted Gradient Echo Sequences

Comparison of Maximum Signal Intensity of Magnevist Contrast Agent in Modified T1 Weighted Spin Echo, T1 Weighted Fast Spin Echo and T1 Weighted Gradient Echo Sequences

Synthesis of nanomedicines by nanohybrids conjugating ginsenosides with auto-targeting and enhanced MRI contrast for liver cancer therapy

A new methodology has been developed with conjugating nanoparticles (NPs) with an active ingredient of Chinese herbs for nanomedicines with auto-targeting and enhanced magnetic resonance imaging (MRI) for liver cancer therapy. Fe@Fe3O4 NPs are first synthesized via the programed microfluidic process, whose surfaces are first modified with –NH2 groups using a silane coupling technique that uses (3-aminopropyl)trimethoxysilane (APTMS) as the coupling reagent and are subsequently activated by the bifunctional amine-active cross-linker [e.g. disuccinimidyl suberate (DSS)]. The model medicines of ginsenosides pre-activated by APTMS are further cross-linked with activated NPs, forming the desired nanomedicines (Nano-Fe-GSS). Sizes and structures of Fe@Fe3O4 NPs were characterized by transmission electron microscopy and X-ray diffraction, revealing that their core-shell structures consist of amorphous boron doped Fe cores and partial crystalline Fe3O4 shells. The accomplishment of coupling reactions in the final nanomedicines is confirmed by the characterization of the composition of NPs and Nano-Fe-GSS via X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy. The nanoparticles’ effects as MRI contrast agents are further investigated by comparing the T2 weighted spin echo imaging (T2WI) in livers before and after intravenous injection and intragastric administration of nanomedicines. The results indicate that these nanomedicines possess enhanced MRI effects. Investigation of the toxicity and metabolism of Nano-Fe-GSS suggests that they are safe to related vital organs. The results provide an efficient alternative route to synthesize desired multi-functional nanomedicines based on NPs and the active ingredients of Chinese herbs, which can promote their potential synergistic effects in anti-tumor therapy.

Quantitative [Fe]MRI determination of the dynamics of PSMA-targeted SPIONs discriminates among prostate tumor xenografts based on their PSMA expression.

There is a need for a quantitative MRI method for iron concentration magnetic resonance imaging suitable for measuring the delivery of targeted superparamagnetic iron oxide nanoparticles (SPIONs) to tumors. To apply our newly developed [Fe]MRI method to the quantitative imaging in both space and time of the iron dynamics of anti-prostate specific membrane antigen (PSMA) conjugated SPIONs within human prostate tumor xenografts in nude mice. Longitudinal. 45 Harlan Sprague Dawley athymic nude mice bearing xenografts from PSMA-positive LNCaP, C4-2 and PSMA-negative DU145 tumors from human prostate tumor cell lines. 1.0 Tesla/ T1 and T2 weighted spin echo. Image intensity and contrast measurements. Student's t-test. The SPION diffusion coefficient within tumors was D = 44.8 ± 2.4 × 10-6 mm2 /s. The iron taken up by PSMA-positive LNCaP and C4-2 tumors was proportional to the tail-vein injected dose from 60 nmol to 1.6 μmol; injection of 1 μmol of iron in anti-PSMA conjugated SPIONs resulted in a tumor [Fe] of 76 μM. Even at the highest iron dose of 1.6 μmol, the PSMA-negative DU145 tumors took up no significant iron from the anti-PSMA conjugated SPIONs. A similar lack of nonspecific uptake was observed when the antibodies against PSMA were omitted from the injected SPION preparation. The fraction of the initial iron dose that was taken up by PSMA-positive tumors was 2.32 ± 0.75% (n = 10); uptake by the PSMA-negative DU145 tumors and for SPIONs without anti-PSMA antibodies was 0.16 ± 0.34% (n = 7) giving a ratio of [Fe] in PSMA + versus PSMA- tumors greater than 15:1 (P = 0.01). Quantitative [Fe]MRI of anti-PSMA conjugated SPIONs discriminated between PSMA-positive LNCaP and C4-2 and PSMA-negative DU145 human prostate tumor xenografts in vivo. 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017. J. MAGN. RESON. IMAGING 2018;48:469-481.

Validating Nonlinear Registration to Improve Subtraction Images for Lesion Detection and Quantification in Multiple Sclerosis.

To propose and validate nonlinear registration techniques for generating subtraction images because of their ability to reduce artifacts and improve lesion detection and lesion volume quantification. Postcontrast T1 -weighted spin echo and T2 -weighted dual echo images were acquired for 20 patients with relapsing-remitting multiple sclerosis (RRMS) on a monthly basis for a year (14 women, average age 33.6 ± 6.9). The T2 -weighted images from the first scan were used as a baseline for each patient. The images from the last scan were registered to the baseline image. Four different registration algorithms used for evaluation included; linear, halfway linear, nonlinear, and nonlinear halfway. Subtraction images were generated after brain extraction, intensity normalization, and Gaussian blurring. Lesion activity changes along with identified artifacts were scored on all four techniques by two independent observers. Additionally, quantitative analysis of the algorithms was performed by estimating the volume changes of simulated lesions and real lesions. For real lesion volume change analysis, five subjects were selected randomly. Subtraction images were generated between all the 11 time points and the baseline image using linear and nonlinear registration for the five subjects. Lesion activity detection resulted in similar performance among the four registration techniques. Lesion volume measurements on subtraction images using nonlinear registration were closer to lesion volume on T2 -weighted images. A statistically significant difference was observed among the four registration techniques while evaluating yin-yang artifacts. Pairwise comparisons showed that nonlinear registration results in the least amount of yin-yang artifacts, which are significantly different. Nonlinear registration for generation of subtraction images has been demonstrated to be a promising new technique as it shows improvement in lesion activity change detection. This approach decreases the number of artifacts in subtraction images. With improved lesion volume estimates and reduced artifacts, nonlinear registration may lead to discarding less subject data and an improvement in the statistical power of subtraction imaging studies.

Prospective motion correction in 2D multishot MRI using EPI navigators and multislice-to-volume image registration.

Prospective motion correction reduces artifacts in MRI by correcting for subject motion in real time, but techniques are limited for multishot 2-dimensional (2D) sequences. This study addresses this limitation by using 2D echo-planar imaging (EPI) slice navigator acquisitions together with a multislice-to-volume image registration. The 2D-EPI navigators were integrated into 2D imaging sequences to allow a rapid, real-time motion correction based on the registration of three navigator slices to a reference volume. A dedicated slice-iteration scheme was used to limit mutual spin-saturation effects between navigator and image data. The method was evaluated using T2 -weighted spin echo and multishot rapid acquisition with relaxation enhancement (RARE) sequences, and its motion-correction capabilities were compared with those of periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER). Validation was performed in vivo using a well-defined motion protocol. Data acquired during subject motion showed residual motion parameters within ±0.5 mm and ±0.5°, and demonstrated a substantial improvement in image quality compared with uncorrected scans. In a comparison to PROPELLER, the proposed technique preserved a higher level of anatomical detail in the presence of subject motion. EPI-navigator-based prospective motion correction using multislice-to-volume image registration can substantially reduce image artifacts, while minimizing spin-saturation effects. The method can be adapted for use in other 2D MRI sequences and promises to improve image quality in routine clinical examinations. Magn Reson Med 78:2127-2135, 2017. © 2017 International Society for Magnetic Resonance in Medicine.

Medial prefrontal cortex deficits correlate with unrefreshing sleep in patients with chronic fatigue syndrome.

Unrefreshing sleep is a hallmark of chronic fatigue syndrome/myalgic encephalomyelitis (CFS). This study examined brain structure variations associated with sleep quality in patients with CFS. 38 patients with CFS (34.8±10.1years old) and 14 normal controls (NCs) (34.7±8.4years old) were recruited. All subjects completed the Hospital Anxiety and Depression Scale, Pittsburgh Sleep Quality Index (PSQI), and Chalder Fatigue Scale (CFQ) questionnaires. Brain MRI measures included global and regional grey and white matter volumes, magnetization transfer T1 weighted (MT-T1w) intensities, and T1 weighted (T1w) and T2 weighted spin echo signal intensities. We performed voxel based group comparisons of these regional brain MRI measures and regressions of these measures with the PSQI and CFQ scales adjusted for age, anxiety and depression, and the appropriate global measure. In CFS patients, negative correlations were observed in the medial prefrontal cortex (mPFC) between PSQI and MT-T1w intensities (family-wise error corrected cluster, PFWE <0.05) and between PSQI and T1w intensities (PFWE <0.05). In the same mPFC location, both MT and T1w intensities were lower in CFS patients compared with NCs (uncorrected voxel P<0.001). This study is the first to report that brain structural differences are associated with unrefreshing sleep in CFS. This result refutes the suggestion that unrefreshing sleep is a misperception in CFS patients and further investigation of this symptom is warranted.

MRI evidence of structural changes in the sacroiliac joints of patients with non-radiographic axial spondyloarthritis even in the absence of MRI inflammation

BackgroundStudies have shown that structural lesions may be present in patients with non-radiographic axial spondyloarthritis (nr-axSpA). However, the relevance of structural lesions in these patients is unclear, particularly without signs of inflammation on magnetic resonance imaging (MRI). We assessed the presence of structural lesions at baseline on MRI in the sacroiliac joints (SIJ) of patients with nr-axSpA with and without SIJ inflammation on MRI.MethodsBone marrow edema (BME) was assessed on short tau inversion recovery (STIR) scans from 185 patients with nr-axSpA, by two independent readers at baseline using the Spondyloarthritis Research Consortium of Canada (SPARCC) score. Structural lesions were evaluated on T1 weighted spin echo scans, with readers blinded to STIR scans, using the SPARCC MRI SIJ structural score. Disease characteristics and structural lesions were compared in patients with SIJ BME (score ≥2) and without SIJ BME (score <2).ResultsBoth SIJ BME and structural lesions scores were available for 183 patients; 128/183 (69.9%) patients had SIJ BME scores ≥2 and 55/183 (30.1%) had scores <2. Frequencies of MRI structural lesions in patients with vs without SIJ BME were: erosions (45.3% vs 10.9%, P < 0.001), backfill (20.3% vs 0%, P < 0.001), fat metaplasia (10.9% vs 1.8%, P = 0.04), and ankylosis (2.3% vs 1.8%, P = ns). Significantly more patients with both SIJ BME and structural lesions were male and/or HLA-B27 positive than patients with only SIJ BME. Mean (SD) spinal scores (23 discovertebral units) were significantly higher in patients with SIJ structural lesions than without: 6.5 (11.5) vs 3.3 (5.1), respectively, P = 0.01.ConclusionsIn patients with nr-axSpA, SIJ structural lesions, particularly erosions, may be present on MRI when radiographs are normal or inconclusive, even in patients negative for MRI SIJ inflammation. They may reflect more severe disease with greater spinal inflammation.Trial RegistrationClinicalTrials.gov, NCT01258738. Registered on 9 December 2010.

Comparison of contrast-enhanced T1 weighted FLAIR SENSE and T1 weighted Spin Echo sequence to detect cranial masses.

Comparison of contrast-enhanced T1 weighted FLAIR SENSE and T1 weighted Spin Echo sequence to detect cranial masses.

Brain imaging: Comparison of T1W FLAIR BLADE with conventional T1W SE

IntroductionAlthough T1 weighted spin echo (T1W SE) images are widely used to study anatomical details and pathologic abnormalities of the brain, its role in delineation of lesions and reduction of artifacts has not been thoroughly investigated. BLADE is a fairly new technique that has been reported to reduce motion artifacts and improve image quality. ObjectiveThe primary objective of this study is to compare the quality of T1-weighted fluid attenuated inversion recovery (FLAIR) images with BLADE technique (T1W FLAIR BLADE) and the quality of T1W SE images in the MR imaging of the brain. The goal is to highlight the advantages of the two sequences as well as which one can better reduce flow and motion artifacts so that the imaging of the lesions will not be impaired. Materials and methodsBrain examinations with T1W FLAIR BLADE and T1W SE sequences were performed on 48 patients using a 1.5T scanner. These techniques were evaluated by two radiologists based on: a) a qualitative analysis i.e. overall image quality, presence of artifacts, CSF nulling; and b) a quantitative analysis of signal-to-noise ratios (SNR), contrast-to-noise ratios (CNR) and Relative Contrast. The statistical analysis was performed using the Kruskal-Wallis non-parametric system. ResultsIn the qualitative analysis, BLADE sequences had a higher scoring than the conventional sequences in all the cases. The overall image quality was better on T1W FLAIR BLADE. Motion and flow-related artifacts were lower in T1W FLAIR BLADE. Regarding the SNR measurements, T1W SE appeared to have higher values in the majority of cases, whilst T1W-FLAIR BLADE had higher values in the CNR and Relative Contrast measurements. ConclusionT1W FLAIR BLADE sequence appears to be superior to T1W SE in overall image quality and reduction of motion and flow-pulsation artifacts as well as in nulling CSF and has been preferred by the clinicians. T1W FLAIR BLADE may be an alternative approach in brain MRI imaging.

Comparison of Maximum Signal Intensity of Magnevist Contrast Agent in Modified T1 Weighted Spin Echo, T1 Weighted Fast Spin Echo and T1 Weighted Gradient Echo Sequences

Background: Nowadays MRI examinations have been widely used in clinical applications for many diagnoses. The use of contrast agent in MRI improves lesion detection and characterization and causes more accurate diagnosis. Objectives: The aim of this study was comparing to optimal dose of Magnevist contrast agent in modified T1W SE (Spin Echo), T1W FSE (Fast Spin Echo) and T1W GRE (GRadient Echo) and effect of scan parameters of these sequences on the maximum SI of Magnevist contrast agent. Material and Method: This study was done on a phantom that was containing test tubes. These test tubes were filled with 30ml saline mixed with different doses of Magnevist contrast agent. In this study, some scan parameters of T1W pulse sequences were changed to achieve optimal parameters for maximum SI of contrast agent. In this study maximum signal intensity of each image was measured by ImageJ software. Results: The results of this study show that there are differences in maximum SI in different T1W pulse sequences with changing scan parameters. This study shows that 0.625 mmol/L of Magnevist has maximum SI in all of sequences. The maximum SI can be seen at GRE, SE and FSE sequences, respectively. Conclusion: Using routine and changed scan parameters, each pulse sequence reaches different maximum SI in specific concentration , which is highest in 2D SPGR (SPoiled GRadient) with flip angle = 75˚ and least in T1W SE with TE (Time of Echo) = 40ms.

Three-dimensional volumetric MRI with isotropic resolution: improved speed of acquisition, spatial resolution and assessment of lesion conspicuity in patients with recurrent soft tissue sarcoma

To assess the acquisition speed, lesion conspicuity, and inter-observer agreement associated with volumetric T(1)-weighted MR sequences with isotropic resolution for detecting recurrent soft-tissue sarcoma (STS). Fifteen subjects with histologically proven recurrent STS underwent MRI, including axial and coronal T(1)-weighted spin echo (T(1)-WSE) (5-mm slice thickness) and coronal 3D volumetric T(1)-weighted (fat-suppressed, volume-interpolated, breath-hold examination; repetition time/echo time, 3.7/1.4 ms; flip angle, 9.5°; 1-mm slice thickness) sequences before and after intravenous contrast administration. Subtraction imaging and multiplanar reformations (MPRs) were performed. Acquisition times for T(1)-WSE in two planes and 3D sequences were reported. Two radiologists reviewed images for quality (>50 % artifacts, 25-50 % artifacts, <25 % artifacts, and no substantial artifacts), lesion conspicuity, contrast-to-noise ratio (CNR(muscle)), recurrence size, and recurrence-to-joint distance. Descriptive and intraclass correlation (ICC) statistics are given. Mean acquisition times were significantly less for 3D imaging compared with 2-plane T(1)-WSE (183.6 vs 342.6 s; P = 0.012). Image quality was rated as having no substantial artifacts in 13/15 and <25 % artifacts in 2/15. Lesion conspicuity was significantly improved for subtracted versus unsubtracted images (CNR(muscle), 100 ± 138 vs 181 ± 199; P = 0.05). Mean recurrent lesion size was 2.5 cm (range, 0.7-5.7 cm), and measurements on 3D sequences offered excellent interobserver agreement (ICC, 0.98 for lesion size and 0.96 for recurrence-to-joint distance with MPR views). Three-dimensional volumetric sequences offer faster acquisition times, higher spatial resolution, and MPR capability compared with 2D T(1)-WSE for postcontrast imaging. Subtraction imaging provides higher lesion conspicuity for detecting recurrent STS in skeletal muscle, with excellent interobserver agreement between readers.