Tesla MR Research Articles

3D MRI-based knee shape and its association with incident osteoarthritis and sex differences (data from OAI dataset)

Purpose: This study utilizes a 3D magnetic resonance imaging (MRI) based statistical shape modeling (SSM) method to analyze differences in bone shape of the knee joint that may be associated with incident OA. The purpose of this study is two-fold: (i) to investigate differences in knee bone shape between incident osteoarthritis (OA) cases and controls; and (ii) to investigate sex differences in bone shape. Methods: 20 subjects (10 women) without radiographic signs of OA at baseline (KL=0), but with incident OA at 4 years follow up (KL=2) (cases) were identified randomly from the Osteoarthritis Initiative dataset and matched for age, BMI, and gender in a ratio of 1:1 to 20 controls (10 women) who did not show radiographic evidence of OA over the examination period (KL=0 at baseline and at 4 years). All 40 subjects underwent right knee 3.0 Tesla MR scans. Baseline sagittal 3D double-echo steady-state (DESS) with water excitation images (field of view = 140 mm, number of slices = 160, slice thickness = 0.7 mm, TE/TR 4.7/16.3 mm, TR pixel spacing (0.37 mm, 0.46 mm)) were processed using an in-house Matlab program that segmented the femur and tibia semi-automatically from a collection of plotted markers. A vertex-to-vertex correspondence of the reference knee was mapped onto each candidate surface using a fully automatic landmark-matching algorithm, invariant of size and rotation. Principal Component Analysis (PCA) of the covariance matrix for the landmarks provided relevant shape information. Each case was described by 20 tibia and femur modes (F1-F20, T1-T20) that represent aspects of the 3D bone shape. The mean shape and±5 standard deviations of each mode are presented (Figure 1). Results: Cases and controls had similar mean age and BMI (cases: age = 58.1±6.6 years, BMI = 26.3±2.9 kg/m2, controls: age = 58.1±7.0 years, BMI = 26.4±2.9 kg/m2, p > 0.05). With respect to femoral modes, cases had significant differences in modes F4 (cases: −97.74±178.08, controls: 92.86±176.39 p = 0.002) and F8 (cases: −44.06±107.89, controls: 41.86±124.02, p = 0.027). Negative values in F4 indicated an increase in the length and width of the lateral condyle of the femur relative to the medial condyle, whereas negative F8 values suggested a deeper trochlear groove. For the tibia, differences were less pronounced. In mode T3, cases were borderline different from control knees (cases: −121.92±283.35, controls: 136.26±471.43, p = 0.052). In T4, cases also showed a trend towards significance (cases: −100.91±337.68, controls: 112.79±297.13, p = 0.053). Negative values represent elevation of the medial tibial plateau in T3, and a flatter posterior tibial slope in T4. With respect to our secondary aim, the analysis of bone shape between sexes with knee OA showed that femoral mode F7 was −40.1±134.5 for men, while it was 57.7±103.8 (p = 0.019) for women. Similarly, mean F13 was significantly different in men (−26.15±86.5) versus women (38.1±93.8, p = 0.0032). Negative values in F7 indicated a narrowed intercondylar notch and shallow trochlear groove, whereas positive values showed widened condyles and a deeper trochlear groove. Negative F13 values yielded both a deeper intercondylar notch and trochlear groove. Tibial mode T3 was also significantly different between men (99.7±435.8) and women (−176.4±256.2, p = 0.045). Shape description for T3 is as above. Conclusions: This study suggests that shape differences including a wider and longer lateral condyle (F4), deeper trochlear groove (F8), elevated medial tibial plateau (T3), and flatter posterior slope (T4), may be associated with incident OA. Also, tibial plateau elevation (T3), intercondylar notch width (F7/F13), and trochlear depth (F7/F13) are associated with sex differences. Future analyses of shape modes may allow for their use as target biomarkers in OA.

The compositional difference between ankle and knee cartilage demonstrated by T2 mapping at 7 Tesla MR

ObjectivesThe aim was to systematically compare T2 relaxation times of the knee and ankle cartilage within subjects at 7T. MethodsTen healthy volunteers were examined by 7 Tesla MR using a three-dimensional triple-echo steady state sequence (3D-TESS). The differences between seven cartilage compartments (patella, femur, proximal tibia, and distal tibia and talus in both medial and lateral facet) were analyzed by ANOVA. ResultsThe results showed statistically significantly higher T2 (mean±standard deviation, in milliseconds) values in patellar (25.8±1.2) and femoral (24.9±1.3) cartilage compared to the tibial (19.2±1) and talar (18.1±0.6ms) cartilage. The cartilages of the medial and lateral facet in the ankle joint were not significantly different (p>0.05). ConclusionsThis is the first study to systematically compare within-subject T2 values in the knee and ankle non-invasively, in vivo. Our results are in agreement with the previous findings demonstrating different biochemical and biomechanical properties between the knee and ankle cartilage.

Regional Cerebral Gray Matter Volume in HIV-Positive Patients with Executive Function Deficits.

To evaluate whether human immunodeficiency virus (HIV)-positive patients with and without executive functions deficits and healthy control subjects differ on cortical thickness and subcortical brain structures volume in vivo. In total, 34 HIV-positive patients with executive functions deficits were compared with 13 HIV-positive patients without executive functions deficits and 19 gender-, age-, and education-matched control subjects. Executive functions impairments were classified by performance on the Wisconsin card sorting test. T1 3-dimensional magnetization prepared rapid gradient echo-weighted imaging was performed using a 1.5 Tesla (magnetic resonance) MR scanner. FreeSurfer software was used to perform cortical reconstruction and volumetric segmentation of subcortical gray matter structures. HIV-positive patients with executive functions deficits had smaller volumes in the right and left caudate compared with the HIV-positive patients without executive functions deficits and control groups. In addition, HIV-positive patients with executive functions deficits had smaller volumes in their left accumbens, right putamen, and globus pallidum compared with the control group. No significant differences in cortical thickness were observed between the groups. HIV-positive patients with executive functions deficits have reduced volumes of several subcortical structures, primarily in the caudate nucleus.

Expulsion of Fibroids to the Endometrial Cavity after Magnetic Resonance Imaging-guided High Intensity Focused Ultrasound Surgery (MRgFUS) Treatment of Intramural Uterine Fibroids.

ObjectivesThis report seeks to introduce some cases of the patients who received magnetic resonance imaging (MRI)-guided high intensity focused ultrasound (HIFU) surgery (MRgFUS)-based intramural uterine fibroids treatment where the post-MRgFUS intramural uterine fibroids decreased in its volume and protruded towards the endometrial cavity to be expelled by hysteroscopy.MethodsOf the 157 patients who had received MRgFUS treatment in the Obstetrics and Gynecology of the Hospital from March, 2015 to February, 2016; this study examined 6 of the cases where, after high intensity focused ultrasound treatment, intramural uterine fibroids protruded towards the endometrial cavity to be removed by hysteroscopic myomectomy. The high intensity focused ultrasound utilized in the cases were Philips Achieva 1.5 Tesla MR (Philips Healthcare, Best, The Netherlands) and Sonalleve HIFU system.ResultsThe volume of fibroids ranged from 26.0 cm3 to 199.5 cm3, averaging 95.6 cm3. The major axis length ranged from 4.0 cm to 8.2 cm, averaging 6.3 cm. Fibroid location in all of the patients was in intramural uterine before treatment but after the high intensity focused ultrasound treatment, the fibroids were observed to protrude towards the endometrial cavity in at least Day 5 or up to Day 73 to allow hysteroscopic myomectomy.ConclusionsIn some cases, after an intramural uterine fibroid is treated with MRgFUS, fibroid volume is decreased and the fibroid protrudes towards the endometrial cavity. In this case, hysteroscopic myomectomy can be a useful solution.

Clinical Consideration of Treatment to Ablate Uterine Fibroids with Magnetic Resonance Imaging-guided High Intensity Focused Ultrasound (MRgFUS): Sonalleve.

ObjectivesMagnetic resonance imaging (MRI)-guided high intensity focused ultrasound surgery (MRgFUS) is a newly emerging non-invasive technique for the treatment of uterine fibroids. The purpose of this study is to review the clinical impact of MRgFUS.MethodsThis study examined 157 patients. The high intensity focused ultrasound (HIFU) utilized in this study was Philips Achieva 1.5 Tesla MR (Philips Healthcare, Best, the Netherlands) and Sonalleve HIFU system. The patients were followed in post-operative Month 1, Month 3, and Month 6 to investigate any change. Then, these were further classified according to the use of uterine stimulant (oxytocin) in parallel, Funaki Type of uterine fibroid, HIFU intensity, and non-perfused volume (NPV) ratio.ResultsWhen the uterine stimulant was utilized, the HIFU intensity was measured at significantly lower levels, compared with the group not using uterine stimulant, and treatment duration was significantly. The NPV ratio was found significantly higher in the group using uterine stimulant. Concerning the correlation between Funaki Type of uterine fibroid and average sonication power, it was found that the closer to Type I, the lower the sonication power, the shorter the treatment duration, and the higher the NPV ratio significantly.ConclusionsIn this study, it was found that the lower the Funaki Types of uterine fibroids, and the higher the NPV ratio immediately after the operation, the larger the uterine fibroid volume decrease and SSS change were. Also, if uterine stimulant was used in parallel in treatment, treatment duration and HIFU intensity could become shorter and lower.

Apparent Diffusion Coefficient Quantification in Determining the Histological Diagnosis of Malignant Liver Lesions.

Purpose: Diffusion Weighted Imaging is an established diagnostic tool for accurate differential diagnosis between benign and malignant liver lesions. The aim of our study was to evaluate the role of Histogram Analysis of ADC quantification in determining the histological diagnosis as well as the grade of malignant liver tumours. To our knowledge, there is no study evaluating the role of Histogram Analysis of ADC quantification in determining the histological diagnosis as well as the grade of malignant liver tumours. Methods: During five years, 115 patients with known liver lesions underwent Diffusion Weighted Imaging in 3Tesla MR scanner prior to core needle biopsy. Histogram analyses of ADC in regions of interest were drawn and were correlated with biopsy histological diagnosis and grading.Results: Histogram analysis of ADC values shows that 5th and 30th percentile parameters have statistically significant potency of discrimination between primary and secondary lesions groups (p values 0.0036 and 0.0125 respectively). Skewness of the histogram can help discriminate between good and poor differentiated (p value 0.17). Discrimination between primary malignancy site in metastases failed for the present number of patients in each subgroup.Conclusion: Statistical parameters reflecting the shape of the left side of the ADC histogram can be useful for discriminating between primary and secondary lesions and also between well differentiated versus moderate or poor. For the secondary malignancies, they failed to predict the original site of tumour.

Intra-Individual, Inter-Vendor Comparison of Diffusion-Weighted MR Imaging of Upper Abdominal Organs at 3.0 Tesla with an Emphasis on the Value of Normalization with the Spleen.

ObjectiveTo compare the apparent diffusion coefficient (ADC) values of upper abdominal organs with 2 different 3.0 tesla MR systems and to investigate the usefulness of normalization using the spleen.Materials and MethodsForty-one patients were enrolled in this prospective study, of which, 35 patients (M:F, 27:8; mean age ± standard deviation, 62.3 ± 12.3 years) were finally analyzed. In addition to the routine liver MR protocol, single-shot spin-echo echo-planar diffusion-weighted imaging using b values of 0, 50, 400, and 800 s/mm2 in 2 different MR systems was performed. ADC values of the liver, spleen, pancreas, kidney and liver lesion (if present) were measured and analyzed. ADC values of the spleen were used for normalization. The Pearson correlation, Spearman correlation, paired sample t test, Wilcoxon signed rank test and Bland-Altman method were used for statistical analysis.ResultsFor all anatomical regions and liver lesions, both non-normalized and normalized ADC values from 2 different MR systems showed significant correlations (r = 0.5196–0.8488). Non-normalized ADC values of both MR systems differed significantly in all anatomical regions and liver lesions (p < 0.001). However, the normalized ADC of all anatomical regions and liver lesions did not differ significantly (p = 0.065–0.661), with significantly lower coefficient of variance than that of non-normalized ADC (p < 0.009).ConclusionNormalization of the abdominal ADC values using the spleen as a reference organ reduces differences between different MR systems, and could facilitate consistent use of ADC as an imaging biomarker for multi-center or longitudinal studies.

Effects of Refractive Errors on Visual Functional Magnetic Resonance Imaging

Objective: The purpose of our study is to evaluate the effects of refractive errors on functional magnetic resonance imaging (fMRI) of visual cortex. Methods and Materials: We performed a prospective study. The study included 13 patients with refractive error (group 1) and 30 emetropic volunteers (group 2). Group 2 was also subgrouped as 20-32 years old (young) and over 45 years old (old) to analyse accommodation effect. fMRI data were acquired with a block design paradigm with 3 Tesla MR system. In both groups, images initially were acquired in normal refractive state. fMRI was performed again in both groups during refractive error. Activation areas on visual cortex were calculated as square centimeter. Total activated areas on visual cortex was compared between normal refractive state and induced/ uncorrected refractive error. Results: In group 1, activation areas of visual cortex during uncorrected refractive error revealed significantly decrease compared with activation areas during corrected refractive error (p=0.001). In group 2, induced myopia resulted significant decrease in activation areas compared with normal refractive state. Decrease in activation areas were significant both in 2 and 4 diopters (D) of myopia compared with normal refractive state (p=0.003, p<0.001 respectively). Both in young and old subgroup, activation areas were significantly decreased during induced myopia. We revealed no difference between young and old subgroups. Conclusion: The refractive errors have a clear effect on fMRI of visual cortex. Thus, to achieve accurate results they should be corrected in patients that included in the visual fMRI study.

A prospective study of magnetic resonance imaging patterns of central nervous system infections in pediatric age group and young adults and their clinico-biochemical correlation.

Background:Infections of the central nervous system (CNS) are common and routinely encountered. Our aim was to evaluate the neuroimaging features of the various infections of the CNS so as to differentiate them from tumoral, vascular, and other entities that warrant a different line of therapy.Aims:Our aim was to analyze the biochemical and magnetic resonance imaging (MRI) features in CNS infections.Settings and Design:This was a longitudinal, prospective study over a period of 1½ years.Subjects and Methods:We studied cerebrospinal fluid (CSF) findings and MRI patterns in 27 patients of 0–20 years age group with clinical features of CNS infections. MRI was performed on MAGNETOM Avanto 18 Channel 1.5 Tesla MR machine by Siemens India Ltd. The MRI protocol consisted of diffusion-weighted and apparent diffusion coefficient imaging, turbo spin echo T2-weighted, spin echo T1-weighted, fluid-attenuated inversion recovery (FLAIR), and gradient-echo in axial, FLAIR in coronal, and T2-weighted in sagittal plane. Contrast-enhanced T1-weighted sequence and MR spectroscopy were done whenever indicated.Results and Conclusions:We found that most of the children belong to 1–10 years age group. Fungal infections were uncommon, mean CSF adenosine deaminase values specific for tuberculosis and mean CSF glucose-lowered in pyogenic. Hemorrhagic involvement of thalamus with/without basal ganglia and brainstem involvement may indicate Japanese encephalitis or dengue encephalitis. Diffusion restriction or hemorrhage in not expected in the brainstem afflicted lesions of rabies. Congenital cytomegalovirus can cause cortical malformations. T1 hyperintensities with diffusion restriction may represent viral encephalitis. Lesions of acute disseminated encephalomyelitis (ADEM) may mimic viral encephalitis. Leptomeningeal enhancement is predominant in pyogenic meningitis. Basilar meningitis in the presence of tuberculomas is highly sensitive and specific for tuberculosis.

Microvasculature alters the dispersion properties of shear waves - a multi-frequency MR elastography study

Magnetic Resonance Elastography (MRE) uses macroscopic shear wave propagation to quantify mechanical properties of soft tissues. Micro-obstacles are capable of affecting the macroscopic dispersion properties of shear waves. Since disease or therapy can change the mechanical integrity and organization of vascular structures, MRE should be able to sense these changes if blood vessels represent a source for wave scattering. To verify this, MRE was performed to quantify alteration of the shear wave speed cs due to the presence of vascular outgrowths using an aortic ring model. Eighteen fragments of rat aorta included in a Matrigel matrix (n=6 without outgrowths, n=6 with a radial outgrowth extent of ~600 µm and n=6 with ~850 µm) were imaged using a 7 Tesla MR scanner (Bruker, PharmaScan). High resolution anatomical images were acquired in addition to multi-frequency MRE (ν = 100, 115, 125, 135 and 150 Hz). Average cs was measured within a ring of ~900 µm thickness encompassing the aorta and were normalized to cs0 of the corresponding Matrigel. The frequency dependence was fit to the power law model cs ~ν(y). After scanning, optical microscopy was performed to visualize outgrowths. Results demonstrated that in presence of vascular outgrowths (1) normalized cs significantly increased for the three highest frequencies (Kruskal-Wallis test, P = 0.0002 at 125 Hz and P = 0.002 at 135 Hz and P = 0.003 at 150 Hz) but not for the two lowest (Kruskal-Wallis test, P = 0.63 at 100 Hz and P = 0.87 at 115 Hz), and (2) normalized cs followed a power law behavior not seen in absence of vascular outgrowths (ANOVA test, P < 0.0001). These results showed that vascular outgrowths acted as micro-obstacles altering the dispersion relationships of propagating shear waves and that MRE could provide valuable information about microvascular changes.

High Resolution MRI Reveals Detailed Layer Structures in Early Human Fetal Stages: In Vitro Study with Histologic Correlation.

An understanding of normal fetal brain development is essential in detecting the early onset of brain disorders. It is challenging to obtain high-quality images that show detailed local anatomy in the early fetal stages because the fetal brain is very small with rapidly-changing complex structures related to brain development, including neurogenesis, neuronal migration, and axonal elongation. Previous magnetic resonance imaging (MRI) studies detected three layers throughout the fetal cerebral wall that showed differences in MR contrasts at 10 gestational weeks (GW), which is one of the earliest ages studied using MRI. Contrary to the MRI studies, histological studies found more layers at this fetal age. The purpose of this work is to study the development of brain structures from an early fetal period to an early second trimester stage using ex vivo MRI and compare it to histology. Special attention was paid to laminar structures in the cerebral wall. T2-weighted imaging was performed on fetal brain specimens ranging from 10 GW to 18 GW on a 4.7 tesla MR scanner. We obtained standard grayscale as well as color-coded images using weighted red-green-blue scales, and compared them with the histological images. Our study confirmed laminar structure in the cerebral wall in all the fetal specimens studied. We found that MRI detected four layers within the cerebral wall as early as 10 GW during the early fetal period (10–13 GW). Early second trimester (15–18 GW) was characterized by the emergence of subplate structures and five layers within the cerebral wall. The color-coded images were more useful than the standard grayscale images in detecting the laminar structures. Scans with appropriate parameters from a high tesla MR scanner showed detailed laminar structures even through a very small and thin cerebral wall at 10 GW ex vivo. A combination of high-resolution structural imaging and color-coding processing with histological analysis may be a potential tool for studying detailed structures of typical developing fetal brains, as well as fetal brains with developmental disorders as references for clinical MRI.

Maternal prenatal iron status and tissue organization in the neonatal brain.

BackgroundChildren prenatally exposed to inadequate iron have poorer motor and neurocognitive development. No prior study to our knowledge has assessed the influence of maternal prenatal iron intake on newborn brain tissue organization in fullterm infants.Methods3rd trimester daily iron intake was obtained using the Automated SelfAdministered 24hour Dietary Recall with n=40 healthy pregnant adolescents (14–19 years old). Cord blood ferritin was collected in a subsample (n=16). Newborn (m=39 gestational weeks at birth; range 37–41) Neonatal MRI scans were acquired on a 3.0 Tesla MR Scanner. Diffusion Tensor Imaging (DTI) slices were acquired to measure the directional diffusion of water indexed by fractional anisotropy (FA).ResultsReported iron intake was inversely associated with newborn FA values (P ≤ .0001) predominantly in cortical gray matter. FA findings were similar using cord blood ferritin values.ConclusionHigher maternal prenatal iron intake accentuates, and lower intake attenuates, the normal age–related decline in FA values in gray matter, perhaps representing increasing dendritic arborization and synapse formation with higher iron intake. These DTI results suggest that typical variation in maternal iron outside the scope of standard clinical surveillance exerts subtle effects on infant brain development.

A New MRI Masking Technique Based on Multi-Atlas Brain Segmentation in Controls and Schizophrenia: A Rapid and Viable Alternative to Manual Masking.

Brain masking of MRI images separates brain from surrounding tissue and its accuracy is important for further imaging analyses. We implemented a new brain masking technique based on multi-atlas brain segmentation (MABS) and compared MABS to masks generated using FreeSurfer (FS; version 5.3), Brain Extraction Tool (BET), and Brainwash, using manually defined masks (MM) as the gold standard. We further determined the effect of different masking techniques on cortical and subcortical volumes generated by FreeSurfer. Images were acquired on a 3-Tesla MR Echospeed system General Electric scanner on five control and five schizophrenia subjects matched on age, sex, and IQ. Automated masks were generated from MABS, FS, BET, and Brainwash, and compared to MM using these metrics: a) volume difference from MM; b) Dice coefficients; and c) intraclass correlation coefficients. Mean volume difference between MM and MABS masks was significantly less than the difference between MM and FS or BET masks. Dice coefficient between MM and MABS was significantly higher than Dice coefficients between MM and FS, BET, or Brainwash. For subcortical and left cortical regions, MABS volumes were closer to MM volumes than were BET or FS volumes. For right cortical regions, MABS volumes were closer to MM volumes than were BET volumes. Brain masks generated using FreeSurfer, BET, and Brainwash are rapidly obtained, but are less accurate than manually defined masks. Masks generated using MABS, in contrast, resemble more closely the gold standard of manual masking, thereby offering a rapid and viable alternative.

Relations between location and type of intracranial atherosclerosis and parenchymal damage

The aim of this study was to assess the relation between location and type of intracranial atherosclerosis (ICAS) and cortical microinfarcts (CMIs) and macroinfarcts in 18 patients presenting with ischemic stroke (n = 12) or transient ischemic attack (TIA) (n = 6) using 7 tesla MR imaging. The protocol included: 3D T2-weighted FLAIR and 3D T1-weighted Magnetization-Preparation Inversion Recovery Turbo Spin Echo sequence. ICAS lesions and infarcts were scored by two raters. The relation between ICAS lesions, calculated ratios of ICAS lesion characteristics, location, and infarcts were examined using linear regression analyses. A total number of 75 ICAS lesions (all patients), 101 CMIs (78% of patients), and 31 macroinfarcts (67% of patients) were found. Seventy-six and sixty-five percent of the CMIs and macroinfarcts, respectively, were found in the same vascular territory as the ICAS lesions (p = 0.977, p = 0.167, respectively). A positive correlation existed between the number of macroinfarcts and CMIs (p < 0.05). In patients with macroinfarcts, we found more concentric (p < 0.01) and diffuse (p < 0.05) type of ICAS lesions. A high prevalence of brain tissue lesions, both macroinfarcts and CMIs, were found in patients with ICAS. Macroinfarcts were found to be related to specific ICAS lesion types. The type of ICAS lesion seems to be promising as a marker for ICAS patients at higher risk of future infarcts.

Generation and Disease Model Relevance of a Manganese Enhanced Magnetic Resonance Imaging-Based NOD/scid-IL-2Rγ c null Mouse Brain Atlas

Strain specific mouse brain magnetic resonance imaging (MRI) atlases provide coordinate space linked anatomical registration. This allows longitudinal quantitative analyses of neuroanatomical volumes and imaging metrics for assessing the role played by aging and disease to the central nervous system. As NOD/scid-IL-2Rγ(c)(null) (NSG) mice allow human cell transplantation to study human disease, these animals are used to assess brain morphology. Manganese enhanced MRI (MEMRI) improves contrasts amongst brain components and as such can greatly help identifying a broad number of structures on MRI. To this end, NSG adult mouse brains were imaged in vivo on a 7.0 Tesla MR scanner at an isotropic resolution of 100 μm. A population averaged brain of 19 mice was generated using an iterative alignment algorithm. MEMRI provided sufficient contrast permitting 41 brain structures to be manually labeled. Volumes of 7 humanized mice brain structures were measured by atlas-based segmentation and compared against non-humanized controls. The humanized NSG mice brain volumes were smaller than controls (p < 0.001). Many brain structures of humanized mice were significantly smaller than controls. We posit that the irradiation and cell grafting involved in the creation of humanized mice were responsible for the morphological differences. Six NSG mice without MnCl2 administration were scanned with high resolution T2-weighted MRI and segmented to test broad utility of the atlas.

Impact of high resolution 3 tesla MR neurography (MRN) on diagnostic thinking and therapeutic patient management.

To evaluate the impact of magnetic resonance neurography (MRN) on diagnostic thinking and therapeutic choices in patients with suspected peripheral neuropathy. IRB approval was obtained for this HIPAA-compliant study. Questionnaires were administered to six surgeons regarding the diagnosis and treatment in 85 patients suspected of having peripheral neuropathy, before (pretest) and after (posttest) MRN. Multiple outcome measures related to diagnostic confidence and surgical decision-making were assessed. The final cohort included 81 patients (30 men and 51 women, age 47 ± 17 years). The following changes were observed from pretest to posttest questionnaires: 23% in nerve involvement (P < 0.05), 48% in degree of confidence of nerve involvement (P < 0.01), 27% in grade of injury (P < 0.05), 33% in differential diagnosis (P < 0.05), 63% in degree of confidence in need for surgery (P < 0.001), 41% in timing of surgery (P < 0.01), 30% in approach to surgery (P < 0.05), 58% in degree of confidence in approach to surgery (P < 0.001), 30% in estimated length of surgery (P < 0.05) and 27% in length of incision (P < 0.05). The dichotomous decision regarding surgical or nonsurgical treatment changed from pro to con in 17%. MRN results significantly influenced the diagnostic thinking and therapeutic recommendations of peripheral nerve surgeons. • In patients with peripheral neuropathy, MRN significantly impacts diagnostic thinking. • In patients with peripheral neuropathy, MRN significantly impacts therapeutic choices. • 3-T MRN should be considered in presurgical planning of patients with peripheral neuropathy.

THE DILEMMA OF THE UNUSUAL DISTRIBUTION OF MR ENCEPHALOPATHY IN PRE-ECLAMPTIC/ECLAMPTIC FEMALE PATIENTS : DETECTION AND PITFALLS

To evaluate the MRI findings in pre-eclamptic/ eclamptic encephalopathy and to evaluate the usefulness of diffusion weighted MRI (DW-MRI) as an imaging tool and its prognostic implication in changing treatment protocol. Patients & methods: Prospective study included24 patients, diagnosed clinically as preeclampsia (14 cases) and eclampsia in (10 cases). Their ages ranged from 25 to 45 years with mean age of 35.6 years. They examined on a standard 1.5 Tesla MR unit. Initially conventional T2 and FLAIRimages were done followed by Diffusion weighted imaging . Results: All 24 patients were acutely hypertensive at presentation. All patients develop abnormal increased signal on T2 and FLAIR sequences predominantly involving the posterior circulation. 20 ofthese patients demonstrate increased SI on diffusion weighted images denoting vasogenic edema while only 4 patients showed corresponding low signal on DW-MRI (cytotoxic edema). Follow up study confirmed the resolution of the lesions (in 20 patients) successfully with reversible neurologic impairment while those 4 patients with cytotoxic edema pattern,they develop permanent T2 / FLAIR hyper intense signal and neurological impairment. Conclusion: Involvement of the parietal and occipital lobes is common in patients with eclampsia, and the signal abnormalities on MRI are reversible if recognized and treated early.DWI can correlates well with the patient's outcome, and should be performed in all eclamptic patients and that may affect greatly their management.

Synthesis, Magnetic Properties, Map Images, and Water Proton Relaxivities of D-Glucuronic Acid Coated Ln2O3 Nanoparticles (Ln = Ho and Er).

T2 MRI contrast agents cannot be synthesized by using molecules but nanoparticles because appreciable magnetic moments at room temperature are needed. Recently, some of lanthanide (Ln) oxide nanoparticles have shown decent magnetic moments at room temperature and even at ultrasmall particle diameters. In this study, we explored D-glucuronic acid coated Ln2O3 nanoparticles (Ln = Ho and Er) with ultrasmall particle diameters. They showed decent magnetic moments at room temperature and as a result, appreciable transverse water proton relaxivities (r2s) at 1.5 tesla MR field. Clear dose-dependent contrast enhancements in R2 map images were observed in both samples. These results showed that D-glucuronic acid coated Ln2O3 nanoparticles (Ln = Ho and Er) would be potential T2 MRI contrast agents at high MR fields.

Q-space MR imaging of gastric carcinoma ex vivo: Correlation with histopathologic findings

The purpose of this study was to establish the feasibility of q-space imaging (QSI) as a method of assessing the depth of mural invasion, histologic grade, and the presence of lymph node metastasis in gastric carcinomas. A 7.0 Tesla MR imaging system was used to investigate 20 gastric specimens containing a carcinoma. QSI was performed by using the following parameters: 50-60 mm × 25-30 mm field of view, 2-mm section thickness, 256 × 128 matrix, 10 b values in the 0-7163 s/mm(2) range, which corresponded to q values of 0-1026/cm, and motion-probing gradients perpendicular to the gastric wall. The MR images and the histopathologic findings were then compared. The depth of tumor invasion of the gastric wall in all 20 carcinomas (100%) was established by using mean displacement, zero-displacement probability, and kurtosis maps. The QSI parameters were significantly correlated with the histologic grades of the gastric carcinomas (all P < 0.001). The QSI parameters made it possible to differentiate between metastatic and nonmetastatic lymph nodes (all P = 0.001). Ex vivo QSI facilitates excellent diagnostics for evaluating gastric carcinomas in terms of mural invasion, histologic grade, and the presence of lymph node metastasis. Magn Reson Med 76:602-612, 2016. © 2015 Wiley Periodicals, Inc.

SU‐E‐J‐217: Multiparametric MR Imaging of Cranial Tumors On a Dedicated 1.0T MR Simulator Prior to Stereotactic Radiosurgery

Purpose:Quantitative magnetic resonance imaging (MRI) of cranial lesions prior to stereotactic radiosurgery (SRS) may improve treatment planning and provide potential prognostic value. The practicality and logistics of acquiring advanced multiparametric MRI sequences to measure vascular and cellular properties of cerebral tumors are explored on a 1.0 Tesla MR Simulator.Methods:MR simulation was performed immediately following routine CT simulation on a 1T MR Simulator. MR sequences used were in the order they were performed: T2‐Weighted Turbo Spin Echo (T2W‐TSE), T2 FLAIR, Diffusion‐weighted (DWI, b = 0, 800 to generate an apparent diffusion coefficient (ADC) map), 3D T1‐Weighted Fast Field Echo (T1W‐FFE), Dynamic Contrast Enhanced (DCE) and Post Gadolinium Contrast Enhanced 3D T1W‐FFE images. T1 pre‐contrast values was generated by acquiring six different flip angles. The arterial input function was derived from arterial pixels in the perfusion images selected manually. The extended Tofts model was used to generate the permeability maps. Routine MRI scans took about 30 minutes to complete; the additional scans added 12 minutes.Results:To date, seven patients with cerebral tumors have been imaged and tumor physiology characterized. For example, on a glioblastoma patient, the volume contoured on T1 Gd images, ADC map and the pharmacokinetic map (Ktrans) were 1.9, 1.4, and 1.5 cc respectively with strong spatial correlation. The mean ADC value of the entire volume was 1141 μm2/s while the value in the white matter was 811 μm2/s. The mean value of Ktrans was 0.02 min‐1 in the tumor volume and 0.00 in the normal white matter.Conclusion:Our initial results suggest that multiparametric MRI sequences may provide a more quantitative evaluation of vascular and tumor properties. Implementing functional imaging during MR‐SIM may be particularly beneficial in assessing tumor extent, differentiating radiation necrosis from tumor recurrence, and establishing reliable bio‐markers for treatment response evaluation.The Department of Radiation Oncology at Henry Ford Health System has research agreement with Varian Medical System and Philips Health Care.