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Despite advances in a wide range of device applications of hydrogels, including implantable ones, a method for deploying patterned hydrogel devices into the body in a minimally‐invasive manner is not available yet. However, in situ patterning of the hydrogel in vivo has an obvious advantage, by which incision surgery for implantation of the hydrogel device can be avoided. Here, a minimally‐invasive and in vivo hydrogel patterning method for in situ fabrication of implantable hydrogel devices is presented. The sequential application of injectable hydrogels and enzymes, with assistance of minimally‐invasive surgical instruments, enables the in vivo and in situ hydrogel patterning. This patterning method can be achieved by adopting an appropriate combination of the sacrificial mold hydrogel and the frame hydrogel, in consideration of unique material properties of the hydrogels such as high softness, facile mass transfer, biocompatibility, and diverse crosslinking mechanisms. In vivo and in situ patterning of the hydrogels functionalized with nanomaterials is also demonstrated to fabricate the wireless heater and tissue scaffold, showcasing broad applicability of the patterning method. [ABSTRACT FROM AUTHOR]

Background: Accurate and rapid measurement of the MRI volume of meningiomas is essential in clinical practice to determine the growth rate of the tumor. Imperfect automation and disappointing performance for small meningiomas of previous automated volumetric tools limit their use in routine clinical practice. Purpose: To develop and validate a computational model for fully automated meningioma segmentation and volume measurement on contrast‐enhanced MRI scans using deep learning. Study Type: Retrospective. Population: A total of 659 intracranial meningioma patients (median age, 59.0 years; interquartile range: 53.0–66.0 years) including 554 women and 105 men. Field Strength/Sequence: The 1.0 T, 1.5 T, and 3.0 T; three‐dimensional, T1‐weighted gradient‐echo imaging with contrast enhancement. Assessment: The tumors were manually segmented by two neurosurgeons, H.K. and C.‐K.P., with 10 and 26 years of clinical experience, respectively, for use as the ground truth. Deep learning models based on U‐Net and nnU‐Net were trained using 459 subjects and tested for 100 patients from a single institution (internal validation set [IVS]) and 100 patients from other 24 institutions (external validation set [EVS]), respectively. The performance of each model was evaluated with the Sørensen‐Dice similarity coefficient (DSC) compared with the ground truth. Statistical Tests: According to the normality of the data distribution verified by the Shapiro–Wilk test, variables with three or more categories were compared by the Kruskal–Wallis test with Dunn's post hoc analysis. Results: A two‐dimensional (2D) nnU‐Net showed the highest median DSCs of 0.922 and 0.893 for the IVS and EVS, respectively. The nnU‐Nets achieved superior performance in meningioma segmentation than the U‐Nets. The DSCs of the 2D nnU‐Net for small meningiomas less than 1 cm3 were 0.769 and 0.780 with the IVS and EVS, respectively. Data Conclusion: A fully automated and accurate volumetric measurement tool for meningioma with clinically applicable performance for small meningioma using nnU‐Net was developed. Evidence Level: 3 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Purpose: Primary central nervous system lymphoma (PCNSL) is an uncommon extranodal non‐Hodgkin's lymphoma. Here, the feasibility of nuclear magnetic resonance (NMR) metabolomics for the diagnosis and prognosis prediction of PCNSL, as well as its correlation with magnetic resonance imaging (MRI) characteristics, was assessed. Patients and Methods: Cerebrospinal fluid (CSF) samples from PCNSL and normal groups (n = 41 for each) were obtained along with MRI data including pre‐ and postcontrast as well as T1‐, T2‐, and diffusion‐weighted imaging for the treatment‐naïve PCNSL patients (n = 24). The CSF samples were analyzed using nuclear magnetic resonance (NMR). Results: The CSF NMR metabolomic exhibited clear differences with a diagnostic sensitivity of 100% and a specificity of 97.6%. The citrate level of the leptomeningeal enhancement (LE) (+) group was significantly lower than that of the LE (−) group (p = 0.018). In addition, the MRI apparent diffusion coefficient (ADC) value of the tumor was positively correlated with the glucose level (p = 0.025). However, none of the marker metabolites were significant prognosis predictors in univariate analysis. Conclusions: In conclusion, the NMR metabolomics could be helpful to diagnose PCNSL, but not for the prognosis, and MRI features (LE or ADC) can reflect the metabolic profiles of PCNSL. [ABSTRACT FROM AUTHOR]

Background: Acceleration of MR imaging (MRI) is a popular research area, and usage of deep learning for acceleration has become highly widespread in the MR community. Joint acceleration of multiple‐acquisition MRI was proven to be effective over a single‐acquisition approach. Also, optimization in the sampling pattern demonstrated its advantage over conventional undersampling pattern. However, optimizing the sampling patterns for joint acceleration of multiple‐acquisition MRI has not been investigated well. Purpose: To develop a model‐based deep learning scheme to optimize sampling patterns for a joint acceleration of multi‐contrast MRI. Methods: The proposed scheme combines sampling pattern optimization and multi‐contrast MRI reconstruction. It was extended from the physics‐guided method of the joint model–based deep learning (J‐MoDL) scheme to optimize the separate sampling pattern for each of multiple contrasts simultaneously for their joint reconstruction. Tests were performed with three contrasts of T2‐weighted, FLAIR, and T1‐weighted images. The proposed multi‐contrast method was compared to (i) single‐contrast method with sampling optimization (baseline J‐MoDL), (ii) multi‐contrast method without sampling optimization, and (iii) multi‐contrast method with single common sampling optimization for all contrasts. The optimized sampling patterns were analyzed for sampling location overlap across contrasts. The scheme was also tested in a data‐driven scenario, where the inversion between input and label was learned from the under‐sampled data directly and tested on knee datasets for generalization test. Results: The proposed scheme demonstrated a quantitative and qualitative advantage over the single‐contrast scheme with sampling pattern optimization and the multi‐contrast scheme without sampling pattern optimization. Optimizing the separate sampling pattern for each of the multi‐contrasts was superior to optimizing only one common sampling pattern for all contrasts. The proposed scheme showed less overlap in sampling locations than the single‐contrast scheme. The main hypothesis was also held in the data‐driven situation as well. The brain‐trained model worked well on the knee images, demonstrating its generalizability. Conclusion: Our study introduced an effective scheme that combines the sampling optimization and the multi‐contrast acceleration. The seamless combination resulted in superior performance over the other existing methods. [ABSTRACT FROM AUTHOR]

Angiomatoid fibrous histiocytomas (AFH) is a rare soft tissue tumor of intermediate malignant potential, and its histology is diverse. It can occur in several organs including intracranial and soft tissues. Here, we report two cases of brain parenchymal classic AFH and spinal extramedullary myxoid mesenchymal tumor with clinicopathological and molecular investigations by next‐generation sequencing and a comprehensive review. The current brain parenchymal AFH occurred in a 79‐year‐old woman, and the spinal myxoid mesenchymal tumor arose in the thoracic spine of a 28‐year‐old woman; both harbored FET:CREB fusion. The current brain parenchymal AFH has not recurred for 15‐months follow‐up period, but the spinal myxoid mesenchymal tumor recurred three times and metastasized to T8 spine level for 30‐months follow‐up period. We reviewed 40 reported cases of central nervous system (CNS) AFHs/myxoid mesenchymal tumors including our two cases to identify clinicopathological features and biological behaviors. They occur with a slight female predominance (M:F = 1:1.7) in children and young adults (median age: 17 years; range: 4–79 years old). Approximately 80% of CNS AFHs were younger than 30 year. Most of them were dura‐based and were not just intracranial tumors as they occurred anywhere in the CNS including spinal dura. EWSR1 rearrangement was the most common driver (98%), including FET:CREB (33%), EWSR1:ATF1 (30%), and EWSR1:CREM (27%) fusions, but FUS:CREM fusion (2%) was also present. During the follow‐up period (median: 27 months), 43% (17/40) of CNS AFHs recurred between two months and 11 years, and multiple recurrences were also observed. One case showed metastases to the lymph nodes and vertebrae, and among 11 cases that resulted in death, four cases provided available clinical data. Because these tumors are identical to soft tissue AFH or primary pulmonary myxoid sarcoma with an FET:CREB fusion in morphological and immunohistochemical spectra, the authors propose incorporating the two tumor terms into one. [ABSTRACT FROM AUTHOR]

Synthetic MRI is a technique that synthesizes contrast‐weighted images from multicontrast MRI data. There have been advances in synthetic MRI since the technique was introduced. Although a number of synthetic MRI methods have been developed for quantifying one or more relaxometric parameters and for generating multiple contrast‐weighted images, this review focuses on several methods that quantify all three relaxometric parameters (T1, T2, and proton density) and produce multiple contrast‐weighted images. Acquisition, quantification, and image synthesis techniques are discussed for each method. We discuss the image quality and diagnostic accuracy of synthetic MRI methods and their clinical applications in neuroradiology. Based on this analysis, we highlight areas that need to be addressed for synthetic MRI to be widely implemented in the clinic. Level of Evidence: 5 Technical Efficacy Stage: 1 [ABSTRACT FROM AUTHOR]

MPE, myxopapillary ependymoma; PFA-EPN, posterior fossa group A ependymoma; PFB-EPN, posterior fossa group B ependymoma; PF-SUBEPN, posterior fossa-subependymoma; PN, ependymoma; SP-EPN, spinal-ependymoma; SP-SUBEPN, spinal subependymoma; ST-EPN-ZFTA, supratentorial-ependymoma ZFTA fusion-positive; ST-SUBEPN, supratentorial subependymoma; YAP1-EPN, ST-ependymoma YAP1-positive gl Our case might be the first case of SP-EPN harboring a I ZFTA-YAP1 i fusion. ZFTA-YAP1 fusion-positive ependymoma can occur in the spinal cord: Letter to the editor Although I ZFTA i fusion-positive EPN occurs mainly in the supratentorial region, one I ZFTA i - I RELA i fusion-positive EPN in the cerebellum and one I ZFTA i - I MAML2 i fusion-positive EPN in the cervical junction have been reported [9]. Unsupervised t-SNE analysis with an overlay on the known ependymal tumor clusters revealed that our case belonged to ST-EPN- I RELA i (now the same as I ZFTA i -fusion-positive ST-EPN), not SP-EPN. [Extracted from the article]

Purpose: To make clinically feasible whole‐brain chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) by enhancing imaging efficiency. Methods: A novel, whole‐brain three‐dimensional (3D) steady‐state CEST MRI method was introduced by utilizing a time‐efficient, fat‐suppressed excitation followed by rapid, segmented 3D echo‐planar‐imaging with incoherent undersampling in k‐ω space. Missing signals and CEST‐specific spectral images were then jointly estimated directly from incomplete measurements using model‐based reconstruction and robust spectral analysis. In vivo studies were performed at 3T both retrospectively (using a fully sampled reference) and prospectively to validate the effectiveness of the proposed method in patients with brain cancer. Results: In retrospective studies, the proposed method exhibits superior accuracies to existing methods in estimating images, z‐spectra, and APTw relative to the reference. In prospective patient studies, compared with existing methods, the proposed method is statistically significantly different in contrast‐to‐noise ratio of the APTw contrast between tumor and normal appearing white matter (NAWM) and amide proton transfer weighted contrast (p < 0.05) while not being significantly different in signal‐to‐noise ratio in an NAWM region. Conclusions: We successfully demonstrated that it is feasible to perform whole‐brain CEST MRI roughly within 4 minutes for patients with brain cancer. It is expected that the proposed method widens clinical utilities of CEST MRI. [ABSTRACT FROM AUTHOR]

Purpose: To develop a set of artificial neural networks, collectively termed qMTNet, to accelerate data acquisition and fitting for quantitative magnetization transfer (qMT) imaging. Methods: Conventional and interslice qMT data were acquired with two flip angles at six offset frequencies from seven subjects for developing the networks and from four young and four older subjects for testing the generalizability. Two subnetworks, qMTNet‐acq and qMTNet‐fit, were developed and trained to accelerate data acquisition and fitting, respectively. qMTNet‐2 is the sequential application of qMTNet‐acq and qMTNet‐fit to produce qMT parameters (exchange rate, pool fraction) from undersampled qMT data (two offset frequencies rather than six). qMTNet‐1 is one single integrated network having the same functionality as qMTNet‐2. qMTNet‐fit was compared with a Gaussian kernel‐based fitting. qMT parameters generated by the networks were compared with those from ground truth fitted with a dictionary‐driven approach. Results: The proposed networks achieved high peak signal‐to‐noise ratio (>30) and structural similarity index (>97) in reference to the ground truth. qMTNet‐fit produced qMT parameters in concordance with the ground truth with better performance than the Gaussian kernel‐based fitting. qMTNet‐2 and qMTNet‐1 could accelerate data acquisition at threefold and accelerate fitting at 5800‐ and 4218‐fold, respectively. qMTNet‐1 showed slightly better performance than qMTNet‐2, whereas qMTNet‐2 was more flexible for applications. Conclusion: The proposed single (qMTNet‐1) and two joint neural networks (qMTNet‐2) can accelerate qMT workflow for both data acquisition and fitting significantly. qMTNet has the potential to accelerate qMT imaging for clinical applications, which warrants further investigation. [ABSTRACT FROM AUTHOR]

Purpose: To develop new artificial neural networks (ANNs) to accelerate slice encoding for metal artifact correction (SEMAC) MRI. Methods: Eight titanium phantoms and 77 patients after brain tumor surgery involving metallic neuro‐plating instruments were scanned using SEMAC at a 3T Skyra scanner. For the phantoms, proton‐density, T1‐, and T2‐weighted images were acquired for developing both multilayer perceptron (MLP) and convolutional neural network (CNN). For the patients, T2‐weighted images were acquired for developing CNN. All networks were trained with the SEMAC factor 4 or 6 as input and the factor 12 as label, yielding an acceleration factor of 3 or 2. Performance of the CNN model was compared against parallel imaging and compressed sensing on the phantom datasets. Two extra T1‐weighted in vivo sets were acquired to investigate generalizability of the models to different contrasts. Results: Both multilayer perceptron and CNN provided artifact‐suppressed images better than the input images and comparable to the label images visually and quantitatively, a trend observable regardless of input SEMAC factor and image type (P <.01). CNN suppressed the artifacts better than multilayer perceptron, parallel imaging, and compressed sensing (P <.01). Tests on the patient datasets demonstrated clear metal artifact suppression visually and quantitatively (P <.01). Tests on T1 datasets also demonstrated clear visual metal artifact suppression. Conclusion: Our study introduced a new effective way of artificial neural networks to accelerate SEMAC MRI while maintaining the comparable quality of metal artifact suppression. Application on the preliminary patient datasets proved the feasibility in clinical usage, which warrants further investigation. [ABSTRACT FROM AUTHOR]

Purpose: Magnetic resonance (MR) imaging with a long scan time can lead to degraded images due to patient motion, patient discomfort, and increased costs. For these reasons, the role of rapid MR imaging is important. In this study, we propose the joint reconstruction of multicontrast brain MR images from down‐sampled data to accelerate the data acquisition process using a novel deep‐learning network. Methods: Twenty‐one healthy volunteers (female/male = 7/14, age = 26 ± 4 yr, range 22–35 yr) and 16 postoperative patients (female/male = 7/9, age = 49 ± 9 yr, range 37–62 yr) were scanned on a 3T whole‐body scanner for prospective and retrospective studies, respectively, using both T1‐weighted spin‐echo (SE) and T2‐weighted fast spin‐echo (FSE) sequences. We proposed a network which we term "X‐net" to reconstruct both T1‐ and T2‐weighted images from down‐sampled images as well as a network termed "Y‐net" which reconstructs T2‐weighted images from highly down‐sampled T2‐weighted images and fully sampled T1‐weighted images. Both X‐net and Y‐net are composed of two concatenated subnetworks. We investigate optimal sampling patterns, the optimal patch size for augmentation, and the optimal acceleration factors for network training. An additional Y‐net combined with a generative adversarial network (GAN) was also implemented and tested to investigate the effects of the GAN on the Y‐net performance. Single‐ and joint‐reconstruction parallel‐imaging and compressed‐sensing algorithms along with a conventional U‐net were also tested and compared with the proposed networks. For this comparison, the structural similarity (SSIM), normalized mean square error (NMSE), and Fréchet inception distance (FID) were calculated between the outputs of the networks and fully sampled images. The statistical significance of the performance was evaluated by assessing the interclass correlation and in paired t‐tests. Results: The outputs from the two concatenated subnetworks were closer to the fully sampled images compared to those from one subnetwork, with this result showing statistical significance. Uniform down‐sampling led to a statically significant improvement in the image quality compared to random or central down‐sampling patterns. In addition, the proposed networks provided higher SSIM and NMSE values than U‐net, compressed‐sensing, and parallel‐imaging algorithms, all at statistically significant levels. The GAN‐based Y‐net showed a better FID and more realistic images compared to a non‐GAN‐based Y‐net. The performance capabilities of the networks were similar between normal subjects and patients. Conclusions: The proposed X‐net and Y‐net effectively reconstructed full images from down‐sampled images, outperforming the conventional parallel‐imaging, compressed‐sensing and U‐net methods and providing more realistic images in combination with a GAN. The developed networks potentially enable us to accelerate multicontrast anatomical MR imaging in routine clinical studies including T1‐and T2‐weighted imaging. [ABSTRACT FROM AUTHOR]

Purpose: To develop a rapid framework for quantitative magnetization transfer (qMT) imaging based on the 2D interslice MT and dictionary‐driven fitting approaches. Methods: Sequential balanced steady‐state free precession (bSSFP) scanning was performed on a whole human brain in a total of 12 conditions from six different interslice gaps and two different flip angles. To obtain qMT maps, the acquired 12 datasets were fitted to a dictionary predefined by using Bloch equation simulations based on the two‐pool MT model. The proposed qMT method was compared to the conventional qMT methods, in terms of qMT parameter maps and processing time. Results: The proposed method yielded qMT maps similar to those of the conventional method, indicating feasibility of modulating MT saturation frequency and power with the interslice gap and flip angle. The whole‐brain qMT imaging could be completed in 8 min because of the absence of separate MT pulses. The time for processing qMT parameters was significantly reduced through the dictionary‐driven approach; it is 1000 times shorter than that without the dictionary‐driven approach and 3 times shorter than that with the spoiled gradient recalled echo‐qMT method that uses an analytical solution. Conclusion: The proposed dictionary–driven interslice qMT imaging provides qMT maps close to those from the conventional method with significantly reduced scan time and postprocessing time, which can make qMT imaging more clinically acceptable. [ABSTRACT FROM AUTHOR]

Background: To determine the diagnostic role of CT added to ultrasound for the diagnosis of recurrent differentiated thyroid cancer (DTC) and to evaluate potential benefits for patients. Methods: A total of 193 patients with recurrent DTC were retrospectively included. The diagnostic performances of ultrasound and combination of ultrasound and CT (ultrasound/CT) in detecting recurrence were compared. Benefits of CT were assessed based on the presence of any recurrence detected only with additional CT. Results: In detecting cervical recurrence, ultrasound/CT showed higher sensitivity (P = .001) and lower specificity (P < .001) than ultrasound alone, overall resulting in higher area under the curve (P < .001). Seventy‐nine patients (40.9%) benefited from additional CT in detecting recurrence. Conclusion: For reoperation of cervical recurrence in patients with DTC, addition of CT to ultrasound offers better surgical planning by enhancing detection of recurrent cancers that were overlooked with ultrasound alone. [ABSTRACT FROM AUTHOR]

Granulomatosis with polyangiitis (GPA), previously known as Wegener’s granulomatosis (WG), is a rare systemic disease characterized by necrotizing granulomas and vasculitis that usually presents in the respiratory tract and renal system. Here, we report a case of anti‐neutrophil cytoplasmic antibody (ANCA)‐negative GPA with diagnostic difficulties. Neurologic involvement in GPA is not uncommon, with up to 50% of patients manifesting with neurologic defects; however, it is usually a late event. This patient was a 50‐year‐old man whose first manifestation was multiple neurologic defects without respiratory or renal symptoms. Since multiple neurologic deficits were the first manifestation and there were no pulmonary or renal symptoms, our patient was treated for 1 year for suspected infectious or inflammatory diseases such as non‐tuberculous mycobacterial infection or immunoglobulin G4 (IgG4)‐related disease with brain involvement; however, his symptoms would wax and wane. Reanalysis of the laboratory findings including biopsies, finally revealed this case to be compatible with GPA. Here, we report a case of GPA, focusing on the diagnostic pitfalls. [ABSTRACT FROM AUTHOR]

Objective To explore the potential preoperative ultrasonography ( US) and cytopathological features to avoid total thyroidectomy in NIFTP. Context Recently, it has been proposed that that noninvasive follicular thyroid neoplasms with papillary-like nuclear features ( NIFTP) be classified as tumours, rather than cancer. Patients A total of 142 surgically proven follicular variant papillary thyroid carcinomas ( FVPTCs; 45 NIFTP, 97 non- NIFTP; mean size: 20.4±11.0 mm, range: 10.0-65.0 mm) from 142 patients were included in this study. Measurements Three preoperative features of thyroid nodules (each US finding, US and Bethesda category) were compared in NIFTP and non- NIFTP groups. The preoperative decision-making process to avoid total thyroidectomy in NIFTP was evaluated based on combination of those features. Results In each US finding, there was only significantly less macrocalcification in the NIFTP group than in the non- NIFTP group (8.8% [4/45] vs 32.0% [31/97], P = .006). In US category, all of the NIFTP nodules were a low or intermediate suspicion (100% [45/45]). In Bethesda category, 26.7% [12/45] of the NIFTP was diagnosed as either suspicious malignancy or malignant, which increased the risk of a total thyroidectomy. In our study, a total thyroidectomy might be avoided in all of the NIFTP cases if lobectomy was selected for the nodules classified as a low or intermediate suspicion in US, despite being classified as a suspicious malignancy or malignant by cytopathology. Conclusions Combining the US and cytopathological results could sensitively reduce total thyroidectomy in cases of NIFTP. [ABSTRACT FROM AUTHOR]

Background Chondroblastoma commonly involves the temporal bone in the craniofacial region, but its imaging features have not been elucidated. This study aimed to describe the imaging features of temporal bone chondroblastoma with their pathologic correlation. Methods Radiopathologic correlation was performed in 5 patients with temporal bone chondroblastoma from our database and in 11 patients identified through a PubMed search. Results The cases of temporal bone chondroblastoma commonly involve the squamous part, temporal and infratemporal fossae, temporomandibular joint, and tympanic cavity, with the following features: high attenuation with calcification; heterogeneity; low signal intensity on T2-weighted imaging with enhancement; a smooth interface to the brain; and strong hypermetabolism on fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT. The heterogeneous low signal intensity on T2-weighted imaging was correlated with various histopathologic components, including calcification and hemosiderin deposition. Conclusion Temporal bone chondroblastoma usually forms as an expansile, heterogeneous, hypermetabolic mass in the middle cranial fossa, frequently with low signal intensity on T2-weighted imaging, reflecting various degrees of calcification and hemosiderin deposition. [ABSTRACT FROM AUTHOR]

Purpose To investigate the performance of control scans in pseudo-continuous ASL (pCASL) and propose strategies for improving sensitivity and reliability of pCASL. Methods The labeling efficiencies of pCASL with conventional control scan and distal control scan were investigated at various radiofrequency (RF) duration/spacing of 0.5/1-2/4 ms, mean slice-selection gradients (GSS) of 1 and 0 mT/m, and total labeling durations of 1.5-3 s, through Bloch equation simulations and in vivo experiments. In addition, the feasibility of three-dimensional (3D) pCASL with the distal control scan and control scan with no RF preparation was demonstrated in a wide brain area, by suppressing the magnetization transfer (MT) effects with high GSS while maintaining the GSS/mean GSS ratio. Results The distal control scan provided pCASL signals approximately 40% higher and more robust to variations in the labeling conditions than those from the conventional control scan. The distal and no RF control scans with high GSS provided uniform pCASL signals in approximately 8-cm-thick imaging region with MT contributions <10% of the perfusion signals. Conclusions pCASL perfusion signals can be enhanced (∼40%) and become more stable by using the distal or no RF control scan, which can be applied in a wide area by increasing GSS while maintaining GSS/mean GSS. Magn Reson Med 78:917-929, 2017. © 2016 International Society for Magnetic Resonance in Medicine. [ABSTRACT FROM AUTHOR]

Purpose To develop single and double acquisition methods to compensate for artifacts from eddy currents and transient oscillations in balanced steady-state free precession (bSSFP) with centric phase-encoding (PE) order for magnetization-prepared bSSFP imaging. Theory and Methods A single and four different double acquisition methods were developed and evaluated with Bloch equation simulations, phantom/in vivo experiments, and quantitative analyses. For the single acquisition method, multiple PE groups, each of which was composed of N linearly changing PE lines, were ordered in a pseudocentric manner for optimal contrast and minimal signal fluctuations. Double acquisition methods used complex averaging of two images that had opposite artifact patterns from different acquisition orders or from different numbers of dummy scans. Results Simulation results showed high sensitivity of eddy-current and transient-oscillation artifacts to off-resonance frequency and PE schemes. The artifacts were reduced with the PE-grouping with N values from 3 to 8, similar to or better than the conventional pairing scheme of N = 2. The proposed double acquisition methods removed the remaining artifacts significantly. The proposed methods conserved detailed structures in magnetization transfer imaging well, compared with the conventional methods. Conclusion The proposed single and double acquisition methods can be useful for artifact-free magnetization-prepared bSSFP imaging with desired contrast and minimized dummy scans. Magn Reson Med 78:254-263, 2017. © 2016 International Society for Magnetic Resonance in Medicine [ABSTRACT FROM AUTHOR]

Purpose To develop a new artifact-suppressed optimal three-dimensional (3D) T1- and T2*-weighted dual-echo imaging. Methods We optimized flip angles for 3D T1- and T2*-weighted imaging by conventional dual-echo in vivo experiments and computer simulations, and then implemented a dual-echo sequence with an echo-specific k-space reordering scheme to satisfy the optimal flip angles for both T1 and T2* contrast. We also proposed two strategies to suppress ringing artifacts induced by the abrupt flip angle jumps in the proposed dual echo sequence: (i) implementing smooth transition regions and (ii) discarding the k-space regions of the abrupt flip angle jumps as dummy phase-encoding steps. Results The optimal flip angles measured from experiments were different between T1- and T2*-weighted contrast, in agreement with simulations. The echo-specific k-space reordered dual-echo sequence showed optimal T1 and T2* contrast simultaneously, but also showed ringing artifacts because of high flip-angle changes between k-space regions. The two proposed strategies effectively suppressed the ringing artifacts. Conclusion The proposed 3D dual-echo sequence provided optimal T1 and T2* contrast simultaneously with no artifacts and thus is potentially applicable to routine clinical applications for simultaneous high resolution T1- and T2*-weighted imaging. Magn Reson Med 76:1504-1511, 2016. © 2015 International Society for Magnetic Resonance in Medicine [ABSTRACT FROM AUTHOR]

Implantable electronic devices for recording electrophysiological signals and for stimulating muscles and nerves have been widely used throughout clinical medicine. Mechanical mismatch between conventional rigid biomedical devices and soft curvilinear tissues, however, has frequently resulted in a low signal to noise ratio and/or mechanical fatigue and scarring. Multifunctionality ranging from various sensing modalities to therapeutic functions is another important goal for implantable biomedical devices. Here, a stretchable and transparent medical device using a cell-sheet-graphene hybrid is reported, which can be implanted to form a high quality biotic/abiotic interface. The hybrid is composed of a sheet of C2C12 myoblasts on buckled, mesh-patterned graphene electrodes. The graphene electrodes monitor and actuate the C2C12 myoblasts in vitro, serving as a smart cell culture substrate that controls their aligned proliferation and differentiation. This stretchable and transparent cell-sheet-graphene hybrid can be transplanted onto the target muscle tissue, to record electromyographical signals, and stimulate implanted sites electrically and/or optically in vivo. Additional cellular therapeutic effect of the cell-sheet-graphene hybrid is obtained by integrated myobalst cell sheets. Any immune responses within implanted muscle tissues are not observed. This multifunctional device provides many new opportunities in the emerging field of soft bioelectronics. [ABSTRACT FROM AUTHOR]

Dopaminergic degeneration is a hallmark of Parkinson's disease (PD), which causes various symptoms affected by corticostriatal circuits. So far, the relationship between cortical changes and dopamine loss in the striatum is unclear. Here, we evaluate the gray matter (GM) changes in accordance with striatal dopaminergic degeneration in PD using hybrid PET/MR. Sixteen patients with idiopathic PD underwent 18F-FP-CIT PET/MR. To measure dopaminergic degeneration in PD, binding ratio (BR) of dopamine transporter in striatum was evaluated by 18F-FP-CIT. Voxel-based morphometry (VBM) was used to evaluate GM density. We obtained voxelwise correlation maps of GM density according to the striatal BR. Voxel-by-voxel correlation between BR maps and GM density maps was done to evaluate region-specific correlation of striatal dopaminergic degeneration. There was a trend of positive correlation between striatal BR and GM density in the cerebellum, parahippocampal gyri, and frontal cortex. A trend of negative correlation between striatal BR and GM density in the medial occipital cortex was found. Voxel-by-voxel correlation revealed that the positive correlation was mainly dependent on anterior striatal BR, while posterior striatal BR mostly showed negative correlation with GM density in occipital and temporal cortices. Decreased GM density related to anterior striatal dopaminergic degeneration might demonstrate degeneration of dopaminergic nonmotor circuits. Furthermore, the negative correlation could be related to the motor circuits of posterior striatum. Our integrated PET/MR study suggests that the widespread structural progressive changes in PD could denote the cortical functional correlates of the degeneration of striatal dopaminergic circuits. Hum Brain Mapp 37:1710-1721, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Recently, balanced steady-state free precession (bSSFP) readout has been proposed for arterial spin labeling (ASL) perfusion imaging to reduce susceptibility artifacts at a relatively high spatial resolution and signal-to-noise ratio (SNR). However, the main limitation of bSSFP-ASL is the low spatial coverage. In this work, methods to increase the spatial coverage of bSSFP-ASL are proposed for distortion-free, high-resolution, whole-brain perfusion imaging. Three strategies of (i) segmentation, (ii) compressed sensing (CS) and (iii) a hybrid approach combining the two methods were tested to increase the spatial coverage of pseudo-continuous ASL (pCASL) with three-dimensional bSSFP readout. The spatial coverage was increased by factors of two, four and six using each of the three approaches, whilst maintaining the same total scan time (5.3 min). The number of segments and/or CS acceleration rate ( R) correspondingly increased to maintain the same bSSFP readout time (1.2 s). The segmentation approach allowed whole-brain perfusion imaging for pCASL-bSSFP with no penalty in SNR and/or total scan time. The CS approach increased the spatial coverage of pCASL-bSSFP whilst maintaining the temporal resolution, with minimal impact on the image quality. The hybrid approach provided compromised effects between the two methods. Balanced SSFP-based ASL allows the acquisition of perfusion images with wide spatial coverage, high spatial resolution and SNR, and reduced susceptibility artifacts, and thus may become a good choice for clinical and neurological studies. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Primary angiitis of the central nervous system ( PACNS) is a vasculitis restricted to the CNS without systemic involvement. We report a case of PACNS that was radiologically tumor-mimicking, and pathologically similar to the Rosai- Dorfmann disease. A 20-year-old woman presented with a focal facial motor seizure. Magnetic resonance image revealed heterogeneously enhanced well-demarcated solitary cerebral mass in the posterior frontal lobe. Histopathologically, the lesion showed lymphoplasmacytic vasculitis with massive parenchymal infiltration of large histiocytes with emperipolesis. Diffuse ischemic change, necrosis, hemorrhage of the brain parenchyma with neuronophagia, and extensive reactive gliosis by gemistocytic astrocytes were accompanying microscopic features. The patient was doing well for 3 years after complete resection of the lesion, except for occasional occurrence of alcohol- or sleep deprivation-associated seizure. We describe this unique case to provide evidence that mass formation can be developed in PACNS by accompanying parenchymal lymphohistiocytic infiltration, necrosis, and marked reactive gliosis. [ABSTRACT FROM AUTHOR]

Glioblastomas ( GBMs) are the most aggressive type of primary brain tumors and provide a dismal prognosis. Thus far, several key genes have been identified in GBMs as prognostic and therapeutic targets. Mutations in two isocitrate dehydrogenase ( IDH) genes, IDH1 and IDH2, commonly occur in low-grade gliomas and secondary high-grade gliomas, but are rare in primary GBMs. These mutations alter the catalytic activity of IDH proteins, promoting gliomagenesis. Gliomas with IDH1 or IDH2 mutation have better outcomes than do gliomas with wild-type IDH. The hot spots of IDH1 mutations ( R132) and IDH2 mutations ( R140 and R172) are well known and are considered as a possible biochemical explanation for the differing clinical characteristics of primary and secondary GBMs. We sought to find the incidence of IDH2 mutation and the characteristics of the gliomas with IDH2 mutation. Among 134 gliomas, which were operated in our hospital consecutively, we studied IDH1 and IDH2 mutations by Sanger sequencing and IDH2 mutation was identified in seven cases (5.2%, four oligodendrogliomas and three GBMs). IDH2 mutation was found in 3.3% of GBMs (3/90 cases) and 9.0% (4/44) of grades II to III gliomas. Here, we report the clinicopathological characteristics of the gliomas with IDH2 mutations including two cases of primary GBM carrying a novel missense IDH2 mutation (c. 484C>T, p. P162S). [ABSTRACT FROM AUTHOR]

The R132H and R172K mutations of isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) have neomorphic activity of generating 2-hydroxyglutarate (2-HG) which has been implicated in the oncogenesis. Although similarities in structure and enzyme activity for the two isotypic mutations have been suggested, the difference in their cellular localization and biochemical properties suggests differential effects on the metabolic oncogenesis. Using U87 cells transfected with either wild-type (WT) and mutant (MT) IDH genes, the MT-IDH1 and MT-IDH2 cells were compared with NMR-based metabolomics. When normalized with the respective WT-IDH cells, the general metabolic shifts of MT-IDH1 and IDH2 were almost opposite. Subsequent analysis with LC-MS and metabolic pathway mapping showed that key metabolites in pentose phosphate pathway and tricarboxylic acid cycle are disproportionately altered in the two mutants, suggesting different activities in the key metabolic pathways. Notably, lactate level was lower in MT-IDH2 cells which produced more 2-HG than MT-IDH1 cells, indicating that the Warburg effects can be overridden by the production of 2-HG. We also found that the effect of a mutant enzyme inhibitor is mainly reduction of the 2-HG level rather than general metabolic normalization. Overall, the metabolic alterations in the MT-IDH1 and 2 can be different and seem to be commensurate with the degree of 2-HG production. [ABSTRACT FROM AUTHOR]

Leptomeningeal carcinomatosis (LC) is a metastatic cancer invading the central nervous system (CNS). We previously reported a metabolomic diagnostic approach as tested on an animal model and compared with current modalities. Here, we provide a proof of concept by applying it to human LC originating from lung cancer, the most common cause of CNS metastasis. Cerebrospinal fluid from LC ( n = 26) and normal groups ( n = 41) were obtained, and the diagnosis was established with clinical signs, cytology, MRI and biochemical tests. The cytology on the CSF, the current gold standard, exhibited 69% sensitivity (∼100% specificity) from the first round of CSF tapping. In comparison, the nuclear magnetic resonance spectra on the CSF showed a clear difference in the metabolic profile between the LC and normal groups. Multivariate analysis and cross-validation yielded the diagnostic sensitivity of 92%, the specificity of 96% and the area under the curve (AUC) of 0.991. Further spectral and statistical analysis identified myo-inositol ( p < 5 × 10−14), creatine ( p < 7 × 10−8), lactate ( p < 9 × 10−4), alanine ( p < 7.9 × 10−3) and citrate ( p < 3 × 10−4) as the most contributory metabolites, whose combination exhibited an receiver-operating characteristic diagnostic AUC of 0.996. In addition, the metabolic profile could be correlated with the grading of radiological leptomeningeal enhancement ( R2 = 0.3881 and p = 6.66 × 10−4), suggesting its potential utility in grading LC. Overall, we propose that the metabolomic approach might augment current diagnostic modalities for LC, the accurate diagnosis of which remains a challenge. [ABSTRACT FROM AUTHOR]

The accurate diagnosis of glioma subtypes is critical for appropriate treatment, but conventional histopathologic diagnosis often exhibits significant intra-observer variability and sampling error. The aim of this study was to investigate whether histogram analysis using an automatically segmented region of interest (ROI), excluding cystic or necrotic portions, could improve the differentiation between low-grade and high-grade gliomas. Thirty-two patients (nine low-grade and 23 high-grade gliomas) were included in this retrospective investigation. The outer boundaries of the entire tumors were manually drawn in each section of the contrast-enhanced T1-weighted MR images. We excluded cystic or necrotic portions from the entire tumor volume. The histogram analyses were performed within the ROI on normalized apparent diffusion coefficient (ADC) maps. To evaluate the contribution of the proposed method to glioma grading, we compared the area under the receiver operating characteristic (ROC) curves. We found that an ROI excluding cystic or necrotic portions was more useful for glioma grading than was an entire tumor ROI. In the case of the fifth percentile values of the normalized ADC histogram, the area under the ROC curve for the tumor ROIs excluding cystic or necrotic portions was significantly higher than that for the entire tumor ROIs ( p < 0.005). The automatic segmentation of a cystic or necrotic area probably improves the ability to differentiate between high- and low-grade gliomas on an ADC map. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Purpose To evaluate the usefulness of pseudo-continuous arterial spin labeling (pCASL) imaging in differentiating high-grade gliomas from lymphomas and in noninvasively predicting genetic biomarkers in high-grade gliomas. Materials and Methods Twelve glioblastoma multiforme (GBM), 3 anaplastic astrocytoma (AA), 5 recurred GBM, and 9 lymphoma patients underwent conventional MR and pCASL imaging. On pCASL perfusion map, mean absolute tumor blood flow (mTBF) was calculated from five regions of interest (ROIs) within the enhancing portion of the tumor. Relative TBF (rTBF = mTBF/mBFgm × 100) was also calculated. mTBF and rTBF of high-grade gliomas and lymphomas were compared using unpaired Student's t-test and receiver operating characteristic (ROC) analysis. Additionally, the association of TBF and six immunohistochemically confirmed genetic biomarkers was analyzed by Pearson correlation analysis in the group of high-grade gliomas. Results Both mTBF and rTBF of the high-grade gliomas were significantly higher than those of the lymphomas: 92.1 ± 34.7 versus 53.6 ± 30.5 mL/min/100 mg ( P = 0.008) and 182.3 ± 69.5 versus 92.5 ± 44.9 ( P = 0.002), respectively. Only epidermal growth factor receptor (EGFR) expression status showed a significant positive correlation with mTBF( P = 0.015) and rTBF( P = 0.007). Conclusion pCASL imaging may facilitate differentiation of high-grade gliomas from lymphomas and prediction of EGFR expression status in high-grade gliomas. J. Magn. Reson. Imaging 2013;38:852-860. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Here, we report a case of lymphoepithelial tumor that developed in the sellar and suprasellar regions in a 56-year-old woman. The lesion was composed of abundant but benign squamous cell nests ( Erdheim's nests) and heavy lymphoid tissue with well-developed lymphoid follicles. Therefore, it mimicked tonsil or adenoid tissue, but was disorganized. We report this case to define the pathogenesis and proper diagnostic terminology of this unusual sellar and suprasellar lesion, and we assume that its origin is the infundibulum. [ABSTRACT FROM AUTHOR]

Extraventricular neurocytoma (EVN) shares histological features with central neurocytoma, but has a wide morphological spectrum. Little is known regarding its clinicopathologic nature, biological behavior and genetic abnormalities. The aim of this study is to examine the diagnostic criteria, genetic abnormalities and biological behavior of EVN. Clinicopathological and molecular genetic studies were performed in seven EVNs. Among them, three cases showed atypical histology. Immunohistochemically, synaptophysin was robustly positive, but neuronal muclear antigen was positive in only half the cases (4/7cases). Isocitrate dehydrogenase enzyme isoform 1 (IDH1) (H09 immunostaining), α-internexin and p53 were negative in all cases. One case was positive for galectin-3. None of the cases showed IDH1 R132 and IDH2 R172 mutation by direct sequencing. One case showed high polysomy of the epidermal growth factor receptor (EGFR) gene; however, O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation and 1p/19q co-deletion were not detected. Array-based comparative genomic hybridization (CGH) study was performed in two cases, revealing different profiles, with loss and gain of multiple chromosomal loci. Two children (18%) had tumor recurrence after initial surgery, and one of them showed worse histology at recurrence and EGFR high polysomy. One patient died from the disease at 18.5 months after surgery. From our study, we concluded that EVNs were characterized by the absence of p53 overexpression, α-internexin positivity, MGMT promotor methylation and IDH1/IDH2 mutation. Oligodendrocyte transcription factor 2 expression was seen in a scattered positive pattern but quite large numbers of tumor cells were negative. EVN is a WHO grade II tumor but some cases (2/7 cases in our series) can show late recurrence but mortality is low (1/7 cases in our series). CGH study suggested genetic heterogeneity of EVNs and unknown subclassification, which requires verification in more cases. [ABSTRACT FROM AUTHOR]

Purpose: To retrospectively determine whether the apparent diffusion coefficient (ADC) values correlate with O6-methylguanine DNA methyltransferase (MGMT) promoter methylation semiquantitatively analyzed by methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) in patients with glioblastoma. Materials and Methods: The study was approved by the Institutional Review Board and was Health Insurance Portability and Accountability Act (HIPAA) compliant. Newly diagnosed patients with glioblastoma ( n = 26) were analyzed with an ADC histogram approach based on enhancing solid portion. The methylation status of MGMT promoter was assessed by methylation-specific polymerase chain reaction (MSP) and by MS-MLPA. MS-MLPA is a semiquantitative method that determines the methylation ratio. The Ki-67 labeling index was also analyzed. The mean and 5th percentile ADC values were correlated with MGMT promoter methylation status and Ki-67 labeling index using a linear regression model. Progression-free survival (PFS) was also correlated with the ADC values using Kaplan-Meier survival analysis. Results: The mean methylation ratio was 0.21 ± 0.20. By MSP, there were 5 methylated and 21 unmethylated tumors. The mean ADC revealed a positive relationship with MGMT promoter methylation ratio ( P = 0.015) and was also significantly different according to MSP-determined methylation status ( P = 0.011). Median PFS was significantly related with methylation ratio ( P = 0.017) and MSP-derived methylation status ( P = 0.025). A positive relationship was demonstrated between PFS and the mean ADC value ( P = 0.001). The 5th percentile ADC values showed a significant negative relationship with Ki-67 labeling index ( P = 0.036). Conclusion: We found that ADC values were significantly correlated with PFS as well as with MGMT promoter methylation status. We believe that ADC values may merit further investigation as a noninvasive biomarker for predicting treatment response. J. Magn. Reson. Imaging 2013;37:351-358. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose. To compare shoulder sonography (US) after intraarticular fluid injection ('arthrosonography') with conventional shoulder US for diagnosing anterior labral tears. Methods. Thirty consecutive patients who were to undergo shoulder MR arthrography were enrolled after written informed consent was obtained. A radiologist performed conventional US, using a 2- to 5-MHz convex transducer on the subject whose arm was externally rotated, then abducted perpendicular to the trunk, and rotated internally and externally. After intraarticular injection of diluted gadolinium contrast for MR arthrography, arthrosonography was performed in the same manner as in the conventional method. Two other radiologists compared the two US methods in the diagnosis of anterior labral tears using a five-point scale. Receiver operating characteristic (ROC) curves and weighted kappa values were calculated. Results. Fourteen patients proven to have anterior labral tears by arthroscopy constituted the disease group, and 16 patients, including the 4 patients who were negative on arthroscopy, constituted the normal group. The areas under the ROC curve of arthrosonography (mean, 0.977) were larger than those of conventional US (mean, 0.858). The kappa values for assessing the interobserver agreement of the two modalities were 0.40 and 0.82, respectively. Conclusions. Arthrosonography of the shoulder is more accurate and reliable than conventional US for diagnosing anterior labral tear. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound 2013 [ABSTRACT FROM AUTHOR]

ABSTRACT Primary intracranial malignant fibrous histiocytoma (MFH) is an extremely rare entity. A few reported cases have been associated with factors such as a previous history of radiation therapy or surgical trauma. We report on a rare case of intracerebral MFH in a previously healthy 47-year-old man, which was initially presumed to be a high-grade glioma. Conventional as well as advanced magnetic resonance sequences, including diffusion-weighted image and perfusion-weighted image, were used in characterization of the mass. [ABSTRACT FROM AUTHOR]

Cellular MRI with a reporter gene offers the opportunity to track small numbers of tumor cells and to study metastatic processes in their earliest developmental stages in the target organs of interest. This study demonstrates the feasibility of using the MR reporter ferritin for the noninvasive imaging and quantification of metastatic melanoma cells in the lymph nodes (LNs) of living mice. A B16F10 murine melanoma cell line expressing human ferritin heavy chain (hFTH) and green fluorescent protein (GFP) was constructed to allow the detection of cells by MRI and fluorescence imaging. Stable overexpression of hFTH and GFP in B16F10 murine melanoma cells was feasible and showed no cellular toxicity. In addition, hFTH cells were detectable by 9.4-T MRI in vitro and in vivo, yielding significant changes in T2* relative to control cells. In BALB/c nude mice, the presence of hFTH- and GFP-expressing metastatic melanoma cells in deep-seated axillary LNs was demonstrated as areas of low T2* on MRI, but the same LNs were not visible by fluorescence imaging because the light was unable to penetrate the tissue. Furthermore, the metastatic volume of each LN, which was assessed by cumulative histogram analysis of the T2* MRI data, correlated well with tumor burden, which was determined by histology ( r = −0.8773, p = 0.0001). This study is the first to use MRI and an MR reporter gene for both the visualization and quantification of metastatic cancer cells in LNs. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Purpose: To compare the diagnostic performance of a diffusion-weighted imaging (DWI) dataset and a gadofluorine M-enhanced imaging dataset for identifying lymph node (LN) metastases in a rabbit rectal cancer model. Materials and Methods: VX2 carcinomas were injected into the rectum of 26 rabbits. Four weeks later, T2-weighted imaging (T2WI), pre-T1WI, DWI, and post-T1WI were performed. Two radiologists independently reviewed the DWI set (T2WI, pre-T1WI, DWI) and the gadofluorine M set (T2WI, pre- and post-T1WI) and recorded their confidence scores for LN metastasis on a per-LN basis. Receiver operating characteristic (ROC) analysis was performed to compare the area under the ROC curve (Az) of the two imaging sets. Histopathologic results were used as the reference standard. Results: The Az and sensitivity of the gadofluorine M set were comparable to those of the DWI set (Az, for reader 1, 0.849, 0.829, P = 0.571; for reader 2, 0.923, 0.876, P = 0.212; sensitivity, for reader 1, 97%, 97%; for reader 2, 97%, 92%, P = 0.304). The specificity of the former was greater than that of the latter (for reader 1, 65%, 53%, P = 0.0003; for reader 2, 81%, 68%, P = 0.01). Conclusion: Gadofluorine M-enhanced images provided greater specificity than DWI for identifying LN metastases, whereas the Az and sensitivity of the former were comparable to those of the latter. J. Magn. Reson. Imaging 2012;. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Purpose: To prospectively compare the diagnostic performances of 1.5 T and 3.0 T ultrasmall superparamagnetic iron oxide (USPIO)-enhanced magnetic resonance imaging (MRI) for the detection of lymph node (LN) metastases in a rabbit model. Materials and Methods: Experiments were approved by the animal care committee. VX2 carcinomas were implanted into the thighs of 18 rabbits 3 or 4 weeks before MRI examinations. T2*-weighted 1.5 T and 3.0 T MRI was performed 24 hours after USPIO (2.6 mg/kg iron) administration. Two radiologists calculated signal intensity (SI) ratios (ie, the ratios of postcontrast to precontrast signal intensity) of each LN and also evaluated for the presence of a metastasis in the iliac and retroperitoneal LNs at 1.5 T and 3.0 T MRI. Student's t-test, receiver operating characteristic (ROC) curve analysis, and a Z test were used for the statistical analysis. Results: Metastases were confirmed in 45 of 80 LNs by histopathology. For benign LNs the mean SI ratio at 1.5 T was higher (0.538) than at 3.0 T (0.463) ( P = 0.004). In qualitative analysis, 1.5 T and 3.0 T USPIO-enhanced MRI showed similar Az values (0.951 vs. 0.939; P = 0.296). The specificity of 3.0 T USPIO-enhanced MRI was higher (91.4% [32 of 35]) than that of 1.5 T imaging (82.9% [29 of 35]) ( P = 0.013); however, the sensitivities (88.9% [40 of 45]) were the same in the both modalities. Conclusion: 3.0 T USPIO-enhanced MRI shows a higher specificity as compared to 1.5 T imaging without a significant difference of sensitivity in a rabbit VX2 model. J. Magn. Reson. Imaging 2010;31:134-141. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

An organized hematoma shows a heterogeneous signal intensity on T1-and T2-weighted images on MR imaging, reflecting variable stages of hemorrhage. Although rather nonspecific, precontrast CT images of an organized hematoma demonstrate inhomogeneous hyperdense mass with or without calcification. We report a case of an organized hematoma in a 44-year-old man, which developed 5 years after decompressive suboccipital craniectomy following acute cerebellar infarction. To our best knowledge, there has been no report describing organized hematoma in the suboccipital craniectomy site. Computed tomography and magnetic resonance imaging findings of the organized hematoma are shown and discussed. We believe that recognition of the characteristic imaging findings of the organized hematoma as well as consideration of the history of surgery or anticoagulation treatment assists in its correct diagnosis enabling an inappropriate surgery to be avoided. [ABSTRACT FROM AUTHOR]

On page 3207, S. H. Choi, D.‐H. Kim, and co‐workers demonstrate a soft and transparent cell‐sheet–graphene hybrid comprising aligned, and differentiated C2C12 myoblasts on buckled, and mesh‐patterned graphene electrodes. The hybrid can monitor and/or actuate electrophysiological signals within muscle tissue without immune responses due to the high quality bio‐interface formed by the integrated cell sheet. Furthermore, transparency of the hybrid allows simultaneous optical stimulation and recording. [ABSTRACT FROM AUTHOR]