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Background: Lower limb ulceration is a common cause of suffering in patients and its management poses a significant burden on the NHS, with venous leg ulcers (VLUs) being the most common hard-to-heal wound in the UK. It is estimated that over one million patients in the UK have lower limb ulceration, of which 560,000 were categorised as VLUs, with a cost burden of over £3 billion each year. Objective: The aim of this service evaluation was to assess the effects of implementing a self-care delivery model on clinical outcomes with the intention of limiting face-to-face health professional contact to one appointment every 6 weeks. Method: A suitability assessment was conducted and a cohort of patients were moved to a self-care delivery model. Patient data were collected, anonymised and independently analysed, comparing time to healing against data on file from a previous report. Results: This highlighted that, in 84 of the 95 patients selected, the VLUs had healed by week 24 on the pathway, a further 10 patients' VLUs had healed by week 42 and only one remaining patient reached 42 weeks without healing. Conclusion: These results support the hypothesis that patients with VLUs can self-care and deliver clinical effectiveness. It is recommended that all services explore the possibility of introducing a self-care model for VLU care.

Purpose Venous oxygenation (Yv) is an important index of brain physiology and may be indicative of brain diseases. A T2-relaxation-under-spin-tagging (TRUST) MRI technique was recently developed to measure Yv. A multisite evaluation of this technique would be an important step toward broader availability and potential clinical utilizations of Yv measures. Methods TRUST MRI was performed on a total of 250 healthy subjects, 125 from the developer's site and 25 each from five other sites. All sites were equipped with a 3 Tesla (T) MRI of the same vendor. The estimated Yv and the standard error (SE) of the estimation eYv were compared across sites. Results The averaged Yv and eYv across six sites were 61.1% ± 1.4% and 1.3% ± 0.2%, respectively. Multivariate regression analysis showed that the estimated Yv was dependent on age (P = 0.009) but not on performance site. In contrast, the SE of the Yv estimation was site-dependent (P = 0.024) but was less than 1.5%. Further analysis revealed that eYv was positively associated with the amount of subject motion (P

The goal of this study was to investigate patterns of axonal injury in the first week after mild traumatic brain injury (mTBI). We performed a prospective cohort study of 20 patients presenting to the emergency department with mTBI, using 3.0T diffusion tensor MRI immediately after injury and again at 1 week post-injury. Corresponding data were acquired from 16 controls over a similar time interval. Fractional anisotropy (FA) and other diffusion measures were calculated from 11 a priori selected axon tracts at each time-point, and the change across time in each region was quantified for each subject. Clinical outcomes were determined by standardized neurocognitive assessment. We found that mTBI subjects were significantly more likely to have changes in FA in those 11 regions of interest across the one week time period, compared to control subjects whose FA measurements were stable across time. Longitudinal imaging was more sensitive to these subtle changes in white matter integrity than cross-sectional assessments at either of two time points, alone. Analyzing the sources of variance in our control population, we show that this increased sensitivity is likely due to the smaller within-subject variability obtained by longitudinal analysis with each subject as their own control. This is in contrast to the larger between-subject variability obtained by cross-sectional analysis of each individual subject to normalized data from a control group. We also demonstrated that inclusion of all a priori ROIs in an analytic model as opposed to measuring individual ROIs improves detection of white matter changes by overcoming issues of injury heterogeneity. Finally, we employed genetic programming (a bio-inspired computational method for model estimation) to demonstrate that longitudinal changes in FA have utility in predicting the symptomatology of patients with mTBI. We conclude concussive brain injury caused acute, measurable changes in the FA of white matter tracts consistent with evolving axonal injury and/or edema, which may contribute to post-concussive symptoms.

Purpose To report a systematic investigation of variations in brain T1ρ (T1-rho) values over adulthood, and present normative values for cortical gray matter, juxtacortical white matter, selected white matter tracts and subcortical structures. Materials and Methods Forty-one healthy control subjects (23 males aged 18–76 years and 18 females aged 21–73 years) were imaged at 3.0 Tesla (T) using a novel whole-brain T1ρ-weighted fluid suppressed three-dimensional turbo spin echo technique. T1ρ maps were calculated and atlas-based segmentation used to determine regional T1ρ values. Linear regression was used to determine changes in T1ρ with age. Results T1ρ values showed significant decreases with age in cortical gray matter (P < 0.001), left and right caudate (P = 0.004/0.006), putamen (P = 0.001, P < 0.001), hippocampus (P = 0.039/0.010), amygdala (P = 0.002/0.001), and nucleus accumbens (P = 0.001/0.002). Significant increases with age (P < 0.05) were observed in all the white matter tracts considered, except the corticospinal tracts and forceps major. Conclusion T1ρ demonstrates changes related to the processes of normal aging. J. Magn. Reson. Imaging 2014;40:376–382. © 2013 Wiley Periodicals, Inc.

T1ρ MRI is an emerging, quantitative imaging modality that has been shown to correlate with proteoglycan content of disk material in vitro at 1.5 T. The purpose of this study is to quantify T1ρ values at all lumbar spine disk space levels at 3 T with parallel-transmission MRI in healthy adult volunteers.Thirty-four subjects (15 men, ages 21-60 years [mean age, 38.4 years]; and 19 women, ages 20-56 years [mean age, 36.5 years]) with no history of back pain or surgery underwent T1ρ MRI of the lumbar spine at 3 T with parallel transmission and sagittal T2-weighted imaging. Mean T1ρ values of all lumbar spine disk space levels were quantified. Linear regression analysis and Spearman rank correlation were performed on age, sex, degenerative grade (Pfirrmann scores), and T1ρ with significance set at p0.05 and correlations considered strong for r0.7 and moderate for r = 0.5-0.7.There was a statistically significant moderate negative correlation between T1ρ and subject age at disk space levels L1-2 through L4-5 (inclusive) (p0.001) and L5-S1 (p0.01). There was a statistically significant difference in T1ρ between all age groups sampled (p0.01) and a significant difference between T1ρ and Pfirrmann grades 1-3 (p0.01).T1ρ MRI in the lumbar spine with parallel transmission shows signifi-cant negative correlations with age at all disk space levels, which lends support to a potential role for T1ρ as a quantitative, in vivo biomarker of disk degeneration.

Background Cardiovascular complications after traumatic brain injury (TBI) contribute to morbidity and mortality and may provide a target for therapy. We examined blood pressure and left ventricle contractility after TBI, and tested the hypothesis that β-adrenergic blockade would decrease oxidative stress after TBI. Material and Methods Rodents received fluid-percussion injury or sham surgery, confirmed with magnetic resonance imaging (MRI) and histopathology. We followed recovery with sensorimotor coordination testing and blood pressure measurements. We assessed left ventricular ejection fraction using ECG-gated cardiac MRI and measured myocardial reactive oxygen species (ROS) with dihydroethidium. We randomized additional TBI and sham animals to postoperative treatment with propranolol or control, for measurement of ROS. Results Blood pressure and cardiac contractility were elevated 48 h after TBI. Myocardial tissue sections showed increased ROS. Treatment with propranolol diminished ROS levels following TBI. Conclusions TBI is associated with increased cardiac contractility and myocardial ROS; decreased myocardial ROS after β-blockade suggests that sympathetic stimulation is a mechanism of oxidative stress.

Purpose: To establish normative magnetic resonance diffusion tensor imaging (MRDTI) data in the pediatric optic nerve and compare to pathologic conditions both intrinsic and extrinsic to the anterior optic nerve pathway. Materials and Methods: A retrospective analysis of MRDTI at 3.0T in children ages 0–18 with both normal imaging studies and with pathologic conditions either arising from the optic nerves or exerting mass effect on the anterior optic pathways was performed. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were obtained within the posterior part of the intraorbital optic nerves. Statistical analysis compared normal controls to optic pathway lesions. Results: Lesions intrinsic to the optic nerve including septo-optic dysplasia and optic nerve glioma demonstrated statistically significant reductions in FA and increases in ADC values. There was no statistically significant difference in FA or mean diffusivity between the normal controls and patients with lesions extrinsic to the optic nerve but exerting mass effect on the visual pathway. Conclusion: MRDTI is a feasible technique for evaluating the optic nerves in pediatric patients. It may play a role in presurgical planning by demonstrating integrity of the visual pathway in patients with resectable lesions, allowing for minimization of morbidity associated with vision loss. J. Magn. Reson. Imaging 2010;32:76–81. © 2010 Wiley-Liss, Inc.

Background/Aims: As a preoperative planning tool, conventional magnetic resonance (MR) imaging may have limited value in differentiating tumors from white matter tracts. MR diffusion tensor imaging (MRDTI) has become a useful tool for evaluating white matter tracts in relation to surrounding structures and has been used in surgical planning for brain tumors involving white matter. We investigated the use of DTI of the optic nerves in surgical planning for pediatric suprasellar tumors. Methods: We present findings in 10 pediatric control patients and 2 cases of pediatric suprasellar tumors in which a routine 6-direction DTI of the brain was performed at 3 T. Postprocessing permitted the study of the diffusion tensor parameters, as well as the tractography, of the optic nerves. Results: The control patients demonstrated the optimization of the technique and permitted the quantitation of fractional anisotropy and apparent diffusion coefficient values. The tumor cases demonstrated the utility of optic nerve DTI to differentiate between optic nerves and suprasellar/chiasmatic brain tumors. Conclusions: A routine 6-direction DTI of the pediatric brain at 3 T permits a detailed DTI study of the optic nerves. Optic nerve tractography can be used to aid in the evaluation and treatment of pediatric brain tumors in the area of the optic chiasm.

Participation in contact sports places athletes at elevated risk for repeated head injuries and is associated with negative mental health outcomes later in life. The current study identified changes observable on neuroimaging that persisted beyond the apparent resolution of acute symptoms of concussion. Sixteen young adult ice hockey players with a remote history of concussion but no subjective complaints were compared against 13 of their teammates with no history of concussion. Participants completed a detailed phenotypic assessment and a neuroimaging battery including diffusion kurtosis imaging and resting-state functional magnetic resonance imaging. Athletes with a history of concussion performed no differently from those without on phenotypic assessment, but showed significantly elevated fractional anisotropy (FA) in the left genu and anterior corona radiata relative to those without. Post hoc analyses revealed that elevated FA was associated with increased microstructural complexity perpendicular to the primary axon (radial kurtosis). Athletes with concussion history also showed significant differences in the organization of the default mode network (DMN) characterized by stronger temporal coherence in posterior DMN, decreased temporal coherence in anterior DMN, and increased functional connectivity outside the DMN. In the absence of deficits on detailed phenotypic assessment, athletes with a history of concussion displayed changes to the microstructural architecture of the cerebral white matter and to the functional connectivity of the brain at rest. Some of these changes are consistent with those previously associated with persisting deficits and complaints, but we also report novel, complementary changes that possibly represent compensatory mechanisms.

Background To apply quantitative whole-brain T1-rho (T1ρ) and T2 imaging to the detection and quantification of brain changes resulting from multiple sclerosis (MS). Methods Twenty-three MS patients with clinically isolated syndrome (10) and relapsing remitting MS (13) phenotypes, compared with 24 age-matched healthy controls were imaged at 3 Tesla. An axial T1ρ-weighted three-dimensional turbo spin echo sequence with a variable flip angle and fluid suppression was used. Spin-lock times of 0, 20, 40, 60, 80, and 100 ms were used. Corresponding T2 maps were also acquired. Results Whole brain white matter (WM) T1ρ maps were elevated compared with controls (P = 0.002). WM lesion T1ρ and T2 values were highly correlated (r = 0.83), but T1ρ demonstrated 25% better contrast to noise ratio (P < 0.001). WM lesion T1ρ correlated with disease duration. Gray matter T1ρ was negatively correlated with the Expanded Disability Status Scale, r = −0.45, P = 0.03. Normal appearing gray matter and cortical gray matter lesions were negatively correlated on T1ρ, but not on T2 (rT1ρ = −0.63, pT1ρ = 0.03; rT2 = −0.17, pT2 = 0.6). Conclusion T1ρ MRI demonstrates enhanced lesion contrast compared with T2, and in some cases may provide complementary information. T1ρ may provide a useful measure of demyelinating processes in MS. J. MAGN. RESON. IMAGING 2015;42:1623–1630.

Objective To investigate the degree to which concussion history and postconcussive symptoms are associated with cortical morphology among male hockey players. Study design Male subjects (n = 29), ranging in age from 14 to 23 years (mean 17.8 years), were recruited from preparatory school and collegiate ice hockey teams and underwent neuroimaging and baseline Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) testing. Cerebral cortical thickness was regressed against ImPACT Total Symptom Score (TSS), concussion history, as well as baseline measures of psychopathology. Reconstruction of surfaces and cortical thickness analysis were conducted with FreeSurfer (version 5.3.0). Results ImPACT TSS was inversely associated with local cortical thickness in widespread brain areas. Associations were revealed in a host of frontal as well as bilateral temporoparietal cortices. Conversely, concussion history was not associated with cortical thickness. An "Age by Concussion History" interaction was associated with thickness in the right ventrolateral and right parietal cortices. Post-hoc analysis revealed that concussed participants did not exhibit age-related cortical thinning in these regions. Conclusion We have identified an association between brain structure and postconcussive symptoms among young, otherwise-healthy male athletes. Postconcussive symptoms and related reductions in cortical thickness may be tied to participation in a full-contact sport that involves frequent blows to the head.

This study investigates the use of [ 99m Tc] liposomes for the detection of sentinel lymph nodes. A variety of [ 99m Tc] liposome formulations were compared with common lymphoscintigraphic agents including [ 99m Tc] regular-sulfur colloid (SC), [ 99m Tc] 0.22 μ-filtered-SC, [ 99m Tc] reduced heating time 0.22 μ-filtered-SC, and [ 99m Tc] human serum albumin (HSA) in rabbits. Images were acquired for the first 60 minutes and at 24 hours, followed by tissue biodistribution study. All agents except [ 99m Tc] regular SC demonstrated good migration from the injection site. Agents were retained in the popliteal node at 24 hours to varying degrees as follows: both [ 99m Tc] filtered SC preparations > [ 99m Tc] regular SC > [ 99m Tc] liposomes > [ 99m Tc] HSA. [ 99m Tc] liposome imaging can be used to develop novel liposome compositions with improved lymph node diagnostic and drug delivery characteristics.

Shifting of echoplanar images (EPI) in the phase-encoding direction during functional magnetic resonance imaging (fMRI) experiments can be observed due to B0 drift. These shifts can cause artifacts in functional activation maps that can be corrected using a navigator echo (NE) technique, but the NE correction requires pulse sequence modifications not available on many clinical systems. A fast, postprocessing correction method based on edge root-mean-square error reduction (ERMSR) is introduced and shown to provide an equivalent correction. J. Magn. Reson. Imaging 2000;12:956–959. © 2000 Wiley-Liss, Inc.

Singular value decomposition (SVD) is a promising deconvolution technique for use in dynamic contrast agent magnetic resonance perfusion imaging. Computer simulations, however, show that the selection of the threshold for SVD affects the accuracy of the cerebral blood flow measurements and may distort the shape of the vascular residue function. In this report, a pixel-by-pixel thresholding method is proposed based on the signal-to-noise ratio of the concentration time curve at maximum concentration (SNRC). Monte Carlo simulations were used to determine the optimal threshold for different SNRC. This technique was used to analyze data from six healthy volunteers, resulting in a mean gray to white matter cerebral blood flow ratio of 2.67 +/- 0.07. This value is in excellent agreement with values published in the literature.

There is emerging evidence that chronic musculoskeletal pain is associated with anatomic and functional abnormalities in gray matter. However, little research has investigated the relationship between chronic musculoskeletal pain and white matter. In this study, we used whole-brain tract- based spatial statistics and region-of-interest analyses of diffusion tensor imaging data to demon- strate that patients with chronic musculoskeletal pain exhibit several abnormal metrics of white matter integrity compared with healthy controls. Chronic musculoskeletal pain was associated with lower fractional anisotropy in the splenium of the corpus callosum and the left cingulum adja- cent to the hippocampus. Patients also had higher radial diffusivity in the splenium, right anterior and posterior limbs of the internal capsule, external capsule, superior longitudinal fasciculus, and cerebral peduncle. Patterns of axial diffusivity (AD) varied: patients exhibited lower AD in the left cingulum adjacent to the hippocampus and higher AD in the anterior limbs of the internal capsule and in the right cerebral peduncle. Several correlations between diffusion metrics and clinical vari- ables were also significant at a P < .01 level: fractional anisotropy in the left uncinate fasciculus corre- lated positively with total pain experience and typical levels of pain severity. AD in the left anterior limb of the internal capsule and left uncinate fasciculus was correlated with total pain experience and typical pain level. Positive correlations were also found between AD in the right uncinate and both total pain experience and pain catastrophizing. These results demonstrate that white matter abnormalities play a role in chronic musculoskeletal pain as a cause, a predisposing factor, a conse- quence, or a compensatory adaptation. Perspective: Patients with chronic musculoskeletal pain exhibit altered metrics of diffusion in the brain's white matter compared with healthy volunteers, and some of these differences are directly related to symptom severity.

Parallel transmission MRI at 3 T improves image quality by reducing dielectric effects with radiofrequency shimming. The purpose of this study was to determine whether parallel transmission MRI improves signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in lumbar spine MRI at 3 T.Ten healthy volunteers underwent T1-weighted MRI and nine healthy volunteers underwent T2-weighted MRI of the lumbar spine. Sagittal and axial T1- and T2-weighted images were acquired using parallel transmission MRI and conventional MRI. The percentage improvements in SNR and CNR were calculated, and statistical significance was determined using a two-tailed Student t test with p0.05 for significance.The CNR and SNR showed statistically significant improvements at all levels of the lumbar spine except SNR at T11 on axial T2-weighted imaging. For sagittal T1-weighted imaging, the average improvement with parallel transmission MRI was 53% in CNR and 19% in SNR. For axial T1-weighted imaging, the average improvement was 48% in CNR and 23% in SNR. For sagittal T2-weighted imaging, the average CNR improvement was 38% and the average SNR improvement, 20%. For axial T2-weighted scans, the average percentage improvement in CNR was greater than 100% and the average SNR improvement was 18% with parallel transmission MRI.The parallel transmission sequence improves image quality of lumbar spine MRI at 3 T, which is quantitatively supported by statistically significant improvements in SNR and CNR.

The purpose of this study is to evaluate the feasibility of ultrafast 3-T MRI in the evaluation of children with acute lower abdominal pain for the detection of appendicitis.Forty-two pediatric patients (30 girls and 12 boys; mean age, 11.5 years; age range, 4-17 years) with acute abdominal pain were prospectively studied. Ultrafast 3-T MRI was performed with a three-plane single-shot turbo spin-echo sequence and an axial T2-weighted turbo spin-echo sequence with fat suppression. All scans were performed without sedation or oral or IV contrast agent. Scan times were less than 8 minutes 45 seconds (median, 5 minutes 40 seconds). Patients underwent CT or ultrasound or both as a comparison study to the MRI examination. The MRI, CT, and ultrasound examinations were interpreted independently by four board-certified radiologists who were blinded to patient information, study interpretations, surgical pathologic findings, and final diagnosis.Twelve of 42 cases of acute appendicitis were detected with 100% sensitivity, 99% specificity, 100% negative predictive value, and 98% positive predictive value, all of which were statistically significant (p0.01). The pooled and individual receiver operating characteristic curves for radiologists' interpretation of the diagnosis of acute appendicitis were greater than 0.95 in all cases (p0.01)Ultrafast 3-T MRI is a feasible alternative imaging modality for the diagnosis of acute appendicitis in children, particularly in cases where ultrasound is equivocal or nondiagnostic, as an alternative to CT. Ultrafast MRI requires no sedation and no oral or IV contrast agent and has no associated radiation exposure risks.

Magnetic resonance imaging (MRI) has been playing an increasingly important role in biomedical research and in clinical diagnosis. The techniques of MRI have experienced rapid development and found wide applications in recent years. The technical development is marked not only by the improvement and optimization of conventional MR imaging techniques but also by the emergence of new pulse sequences such as CEST-MRI (Chemical Exchange Saturation Transfer MRI) and DWIBS (Diffusion-weighted Whole-body Imaging with Background body signal Suppression) and by new techniques such as compressed sensing MRI and MR fingerprinting. The wide proliferation of MRI techniques has led to ever-increasing applications of MR imaging and enormous new findings in basic biomedical research as well as clinical sciences. This special issue aims at reflecting the advances in MR imaging techniques and applications. After rigorous review procedures, the selected papers in this special issue demonstrate how broad the field of MRI has become since Paul Lauterbur's classic paper in 1973. The types of papers include review articles as well as original research. Within this issue are papers that study not only data acquisition and reconstruction methods but also specialized analysis methods and new combinations of MR with therapeutic and interventional techniques. The imaging methods cover structural MRI, functional MRI, diffusion-weighted imaging, and diffusion tensor imaging. The applications addressed are similarly wide reaching, containing cancer, liver diseases, brain function, and so forth. Of particular note, this special issue contains several papers on perhaps the most common use of MRI in MR research centers: functional MRI (fMRI) of the brain. Neuronal activation in the brain results in local increase in the oxygen-enriched blood in capillaries associated with the signal change measured in traditional BOLD-based fMRI. One paper (J. Chung et al.) examines the fusiform face region and the fundamental confoundedness of the signal of blood from large vessels causing a mismatch between the localization of neuronal activation and that of fMRI signal. Once considered to be simply “physiological noise,” certain characteristic fluctuations in the fMRI signal during rest have been shown to be associated with specific neuronal networks. Due to the practical appeal of fMRI without tasks, we are including two review papers reflecting the recent great interest in clinical methods for “resting state” fMRI, one for multiple sclerosis (E. Sbardella et al.) and the other for psychiatric disorders (X. Zhan et al.). In a related paper (X. Li et al.), a temporal decomposition method is presented which decomposes a single brain functional network into several modes to explore dynamic brain functional networks in a continuous, “state-related,” “finger-force feedback” fMRI experiment. Finally, two papers are included which highlight some of the many ways in which advanced data acquisition (D. Kang et al.) and image reconstruction methods (P. K. Han et al.), such as segmented echo-planar imaging (EPI) and compressed sensing, can help to overcome some of the image quality obstacles of fMRI at high field strength. Two other neuro-MRI studies are presented as well regarding areas of strong interest in MR: diffusion tensor imaging (DTI) and MR guidance. In the first paper (T.-K. Truong et al.), a new method is presented for the correction of eddy current-induced echo-shifting effect that produces three types of artifacts, namely, the eddy current induced signal loss, the artificial signal modulation due to eddy current-induced erroneous T2∗ weighting, and artificial signal elevation associated with partial Fourier reconstruction. The second paper (E. Vaghefi et al.) presents an MRI-based technique to guide the noninvasive transcranial brain stimulation without the use of a neuronavigation system. As MR has matured technically primarily for neuroapplications, it has also proven to be increasingly useful for body imaging. An example is the technique of real-time MR thermometry guidance for ultrasound ablation of uterine fibroids, in which excessive skin heating has been an obstacle. To address this issue, the feasibility and safety of utilizing a water-cooled device in contact with the skin are proposed and examined in a paper (M. Ikink et al.). Another “hot topic” in body MR has been the study of liver fibrosis, using a variety of MR methods (e.g., MR elastography and DWI). In this issue, a paper (T. Yokoo et al.) is included which examines the use of a combined Gd and USPIO contrast agent together with texture analysis to better depict the reticular signal abnormalities associated with fibrosis. In a review of MRI for Crohn's Disease (K. Yoon et al.), a variety of methods are presented for inflammatory bowel disease including endoluminal and intravenous contrast agents, DWI, dynamic bowel motility imaging, and MR spectroscopy of fecal and urine samples. Finally, MR-based molecular imaging is presented in a review paper (J. H. Kim et al.) focusing on labelling stem cell with nanoparticles in urology to evaluate migration and survival of transplanted stems cells in prostate cancer and bladder dysfunction models. With the many technical advances in the field, several MR methods have demonstrated their utility in terms of oncology. One paper (I. Thomassin-Naggara et al.) reviews the impact of perfusion and diffusion MRI and a new diagnostic MR scoring system (Adnex MR) upon the preoperative diagnostic accuracy in women with possible ovarian cancer. The utility of combining structural, perfusion, diffusion, and MR spectroscopy data is also presented in this issue for tumour relapse prediction using multiparametric analysis in glioblastoma patients (E. Vaghefi et al.). The use of MR (using diffusion MR and/or dynamic contrast enhancement) to predict the response to neoadjuvant therapy is presented in two papers (G.-Y. Zhang et al. and M. Petrillo et al.) focusing on nasopharyngeal carcinoma and rectal cancer, respectively. In summary, the papers collected in this special issue cover a wide range of topics that are on the frontier of the MRI techniques and their applications.

SUMMARY: 1H-MR spectroscopy is an established noninvasive MR imaging technique that can be helpful in the diagnosis of brain lesions and in treatment planning. Claustrophobia and body habitus preclude some patients from routine MR imaging in a closed-bore system. The development of 1H-MR spectroscopy for use in an open MR imaging system would enable a more complete characterization of brain lesions in these patients. CH2 : methyl Cho : choline Cr : creatine FLAIR : fluid-attenuated inversion recovery 1H-MR spectroscopy : proton MR spectroscopy NAA : N -acetylaspartate PML : progressive multifocal leukoencephalopathy PRESS : point-resolved spectroscopic sequence SNR : signal-to-noise ratio SVS : single-voxel spectroscopy

Object Cavernous malformations (CMs) can cause symptoms that appear out of proportion to the lesion size, leading one to hypothesize that they may have an effect on adjacent white matter that is not fully explained by local mass effect. The goal of this study was to investigate the diffusion tensor (DT) properties of CMs, the hemosiderin rim, and normal-appearing adjacent white matter. Methods Eighteen cavernous malformations were characterized using standard MR imaging sequences as well as 6-direction DT imaging with single-shot echo planar–gradient echo imaging at 3 tesla. Results Diffusion tensor imaging demonstrated that CMs have a characteristic signature on DT imaging, with low fractional anisotropy (FA) and high mean diffusivity centrally within the lesion. The hemosiderin rim had a high FA value relative to the central lesion or adjacent white matter. Tractography revealed that tracts neatly deviate around CMs. Tracts were typically seen to pass through the hemosiderin rim. Conclusions The hemosiderin rim of CMs was intimately associated with white matter tracts that were deviated by the central lesion. These findings are consistent with histopathological reports that the hemosiderin rim is composed of blood breakdown products deposited in viable white matter.

To investigate the feasibility of routine clinical DTI of the lower spinal cord using high-field-strength MRI and parallel imaging, and to evaluate the utility of diffusion tensor imaging and tractography as tools for study of lower cord pathology. Three patients with diastematomyelia, one patient with tethered cord, and six normal volunteers underwent MR imaging of the lower spine at 3 T. A 15-channel spine coil and parallel imaging were used with a six-direction single-shot echo-planar gradient echo technique. In normal volunteers, tractography delineated the conus and cauda equina. Tractography software permitted assessment of fractional anisotropy of the distal cord and nerve roots. In cases of tethered cord, tractography correlated with anatomical imaging. Tractography also correlated with the anatomical pathological findings in cases of diastematomyelia. The methods described enable routine DTI and tractography of the lower spinal cord at 3 T. Compared with conventional imaging, tractography offers additional information that may prove useful in the characterization and surgical planning for congenital lesions involving the lower spinal cord.