Weighted MRI Scans Research Articles

Morphological alterations of the corpus callosum in antipsychotic-naive first-episode schizophrenia before and 1-year after treatment

ObjectiveThe corpus callosum (CC) is known to be altered in patients with schizophrenia. However, its morphologic characteristics are less well studied in treatment-naive first-episode schizophrenia patients, as is the effect of antipsychotic treatment on this structure. MethodsT-1 weighted MRI scans were obtained from 160 antipsychotic-naïve first-episode schizophrenia patients (AN-FES) and 155 healthy controls (HCs) before treatment initiation. Among the patients, forty-four were available for follow-up studies after one year of antipsychotic treatment, and were divided into good-outcome (n = 31) and poor-outcome subgroups (n = 13) based on whether there was a 50% reduction in Positive and Negative Symptom Scale (PANSS) total scores from baseline. A computer algorithm was applied to automatically identify the mid-sagittal plane (MSP) and obtain morphological measurement parameters of the CC. ResultsCompared with HCs, AN-FES patients showed a significant reduction of thickness in the posterior midbody of the CC. This deficit was correlated with severity of negative symptoms. After one year of antipsychotic treatment, there was no significant change in CC morphological measurements in schizophrenia patients, nor was there a significant difference of CC morphological measurements between good-outcome and poor-outcome subgroups at baseline or at 1-year follow-up. ConclusionThickness of the posterior midbody of the CC is reduced in the early course of schizophrenia before treatment. This alteration was not affected by antipsychotic treatment and was unrelated to treatment outcome at 1-year.

Deep Learning Corpus Callosum Segmentation as a Neurodegenerative Marker in Multiple Sclerosis.

Corpus callosum atrophy is a sensitive biomarker of multiple sclerosis (MS) neurodegeneration but typically requires manual 2D or volumetric 3D-based segmentations. We developed a supervised machine learning algorithm, DeepnCCA, for corpus callosum segmentation and relate callosal morphology to clinical disability using conventional MRI scans collected in clinical routine. In a prospective study of 553 MS patients with 704 acquisitions, 200 unique 2D T2 -weighted MRI scans were delineated to develop, train, and validate DeepnCCA. Comparative FreeSurfer segmentations were obtained in 504 3D T1 -weighted scans. Both FreeSurfer and DeepnCCA outputs were correlated with clinical disability. Using principal component analysis of the DeepnCCA output, the morphological changes were explored in relation to clinical disease burden. DeepnCCA and manual segmentations had high similarity (Dice coefficients 98.1 .11%, 89.3 .76%, for intracranial and corpus callosum area, respectively through 10-fold cross-validation). DeepnCCA had numerically stronger correlations with cognitive and physical disability as compared to FreeSurfer: Expanded disability status scale (EDSS) ±6 months (r = -.22 P = .002; r = -.17, P = .013), future EDSS (r = -.26, P<.001; r = -.17, P = .012), and future symbol digit modalities test (r = .26, P = .001; r = .24, P = .003). The corpus callosum became thinner with increasing cognitive and physical disability. Increasing physical disability, additionally, significantly correlated with a more angled corpus callosum. DeepnCCA (https://github.com/plattenmichael/DeepnCCA/) is an openly available tool that can provide fast and accurate corpus callosum measurements applicable to large MS cohorts, potentially suitable for monitoring disease progression and therapy response.

Predicting the progression of Parkinson's disease using conventional MRI and machine learning: An application of radiomic biomarkers in whole-brain white matter.

This study aimed to develop and validate a radiomics model based on whole-brain white matter and clinical features to predict the progression of Parkinson disease (PD). PD patient data from the Parkinson's Progress Markers Initiative (PPMI) database was evaluated. Seventy-two PD patients with disease progression, as measured by the Hoehn-Yahr Scale (HYS) (stage 1-5), and 72 PD patients with stable PD were matched by sex, age, and category of HYS and included in the current study. Each individual's T1 -weighted MRI scans at the baseline timepoint were segmented to isolate whole-brain white matter for radiomics feature extraction. The total dataset was divided into a training and test set according to subject serial number. The size of the training dataset was reduced using the maximum relevance minimum redundancy (mRMR) algorithm to construct a radiomics signature using machine learning. Finally, a joint model was constructed by incorporating the radiomics signature and clinical progression scores. The test data were then used to validate the prediction models, which were evaluated based on discrimination, calibration, and clinical utility. Based on the overall data, the areas under curve (AUCs) of the joint model, signature and Unified Parkinson Disease Rating Scale III PD rating score were 0.836, 0.795, and 0.550, respectively. Furthermore, the sensitivities were 0.805, 0.875, and 0.292, respectively, and the specificities were 0.722, 0.697, and 0.861, respectively. In addition, the predictive accuracy of the model was 0.827, the sensitivity was 0.829 and the specificity was 0.702 for stage-1 PD. For stage-2 PD, the predictive accuracy of the model was 0.854, the sensitivity was 0.960, and the specificity was 0.600. Our results provide evidence that conventional structural MRI can predict the progression of PD. This work also supports the use of a simple radiomics signature built from whole-brain white matter features as a useful tool for the assessment and monitoring of PD progression.

Differential white and gray matter damage in highly active multiple sclerosis: A prospective cohort study

We analyze the differential brain volume changes in highly active multiple sclerosis (HAMS) vs. non-HAMS patients during the disease onset. MethodsHAMS was defined as: a) patients with 1 relapse in the previous year and at least 1 T1 gadolinium-enhancing lesion or 9 or more T2 lesions while on therapy with other disease modifying treatment (DMD); or b) patients with 2 or more relapses in the previous year, whether on DMD or not. High-resolution T1 weighted MRI scans were acquired at onset and every 12 months for 2 years. Lesion load and brain volume measurements were determined. At onset, gray matter volume (GMV) and white matter volume (WMV) tissue volumes were calculated using the SIENAX. Longitudinal changes were estimated by using SIENA to calculate the percentage of brain volume loss. Differences between volumes per group at onset and at the end of the follow up were established. Results64 patients, mean age 38.4 years, 35 (57%) women were included. A total of 14 (21%) were classified as HAMS. At onset, HAMS patients showed lower GMV and WMV volume compared with non-HAMS patients (p = 0.003 and p = 0.01, respectively). During the follow up, HAMS patients showed a higher decrease in GM volume compared with non-HAMS patients (-0.61 vs. – 0.77, p < 0.001) independent from new lesion as well as relapse rate activity during follow up. ConclusionHAMS increased rates of GMV atrophy over 24 months compared to non-HAMS patients independent from relapse rate and new T2 lesions.

Neuroanatomical predictors of response to subcallosal cingulate deep brain stimulation for treatment-resistant depression

Deep brain stimulation targeting the subcallosal cingulate gyrus (SCG DBS) improves the symptoms of treatment-resistant depression in some patients, but not in others. We hypothesized that there are pre-existing structural brain differences between responders and nonresponders to SCG DBS, detectable using structural MRI. We studied preoperative, T1-weighted MRI scans of 27 patients treated with SCG DBS from 2003 to 2011. Responders (n = 15) were patients with a >50% improvement in Hamilton Rating Scale for Depression score following 12 months of SCG DBS. Preoperative subcallosal cingulate gyrus grey matter volume was obtained using manual segmentation by a trained observer blinded to patient identity. Volumes of hippocampus, thalamus, amygdala, whole-brain cortical grey matter and white matter volume were obtained using automated techniques. Preoperative subcallosal cingulate gyrus, thalamic and amygdalar volumes were significantly larger in patients who went on to respond to SCG-DBS. Hippocampal volume did not differ between groups. Cortical grey matter volume was significantly smaller in responders, and cortical grey matter:white matter ratio distinguished between responders and nonresponders with high sensitivity and specificity. Normalization by intracranial volume nullified some between-group differences in volumetric measures. There are structural brain differences between patients with treatment-resistant depression who respond to SCG DBS and those who do not. Specifically, the structural integrity of the subcallosal cingulate gyrus target region and its connected subcortical areas, and variations in cortical volume across the entire brain, appear to be important determinants of response. Structural MRI shows promise as a biomarker in deep brain stimulation for depression, and may play a role in refining patient selection for future trials.

Mapping acute lesion locations to physiological swallow impairments after stroke.

Dysphagia is a common deficit after a stroke, and it is frequently associated with pneumonia, malnutrition, dehydration, and poor quality of life. It is not yet fully clear which brain regions are directly related to swallowing, and how lesions affect swallow physiology. This study aimed to assess the statistical relationship between acute stroke lesion locations and impairment of specific aspects of swallow physiology. We performed lesion symptom mapping with 68 retrospectively recruited, acute, first-ever ischemic stroke patients. Lesions were determined on diffusion weighted MRI scans. Post-stroke swallow physiology was determined using the Modified Barium Swallow Study Impairment Profile (MBSImP©™). The relationship between brain lesion location and 17 physiological aspects of swallowing were tested using voxel-based and region-based statistical associations corrected for multiple comparisons using permutation thresholding. We found that laryngeal elevation, anterior hyoid excursion, laryngeal vestibular closure, and pharyngeal residue were associated with lesioned voxels or regions of interests. All components showed distinct and overlapping lesion locations, mostly in the right hemisphere, and including cortical regions (inferior frontal gyrus, pre- and postcentral gyrus, supramarginal gyrus, angular gyrus, superior temporal gyrus, insula), subcortical regions (thalamus, amygdala) and white matter tracts (superior longitudinal fasciculus, corona radiata, internal capsule, external capsule, ansa lenticularis, lenticular fasciculus). Our findings indicate that different aspects of post-stroke swallow physiology are associated with distinct lesion locations, primarily in the right hemisphere, and primarily including sensory-motor integration areas and their corresponding white matter tracts. Future studies are needed to expand on our findings and thus, support the development of a neuroanatomical model of post-stroke swallow physiology and treatment approaches targeting the neurophysiological underpinnings of swallowing post stroke.

159. Evaluation of a user-guided deformable registration workflow for multi-modal (CT-MRI) prostate imaging

Purpose Reg-refine is a tool that adds human knowledge to deformable image registration (DIR) process. In this study a CT-MRI deformable registration workflow for prostate cancer was evaluated. Methods Deformable and rigid alignments of axial CT and axial T2 weighted MRI scans of 8 patients were evaluated using MIM Maestro 6.7.10 (Mim Software Inc.). DIR workflow consisted of three rigid alignments, in the upper, middle, ad lower prostate part, defined by two users in consensus using Reg-refine, and converted in local alignments by the DIR algorithm. Dice coefficient and Hausdorff distance were computed for evaluation of deformable and rigid alignments. Results Rice resulted (0.78 ± 0.12; max 0.9, min 0.58) for rigid registration vs (0.89 ± 0.05; max 0.94, min 0.82). Hausdorff distance resulted resulted (11.7 mm ± 4.5 mm; max 17.1, min 5.4) for rigid registration vs (7.6 mm ± 4.1 mm; max 13.5 mm, min 3.5 mm). Box plots are reported in Fig. 1. Conclusions The DIR workflow evaluated in this study produced good results in all patients analyzed and was able to improve the registration accuracy of rigid alignments. Reg-refine based DIR of CT and MRI scans can be used for prostate contouring.

A Machine Learning Approach to Perfusion Imaging With Dynamic Susceptibility Contrast MR.

Background: Dynamic susceptibility contrast (DSC) MR perfusion is a frequently-used technique for neurovascular imaging. The progress of a bolus of contrast agent through the tissue of the brain is imaged via a series of T2*-weighted MRI scans. Clinically relevant parameters such as blood flow and Tmax can be calculated by deconvolving the contrast-time curves with the bolus shape (arterial input function). In acute stroke, for instance, these parameters may help distinguish between the likely salvageable tissue and irreversibly damaged infarct core. Deconvolution typically relies on singular value decomposition (SVD): however, studies have shown that these algorithms are very sensitive to noise and artifacts present in the image and therefore may introduce distortions that influence the estimated output parameters.Methods: In this work, we present a machine learning approach to the estimation of perfusion parameters in DSC-MRI. Various machine learning models using as input the raw MR source data were trained to reproduce the output of an FDA approved commercial implementation of the SVD deconvolution algorithm. Experiments were conducted to determine the effect of training set size, optimal patch size, and the effect of using different machine-learning models for regression.Results: Model performance increased with training set size, but after 5,000 samples (voxels) this effect was minimal. Models inferring perfusion maps from a 5 by 5 voxel patch outperformed models able to use the information in a single voxel, but larger patches led to worse performance. Random Forest models produced had the lowest root mean squared error, with neural networks performing second best: however, a phantom study revealed that the random forest was highly susceptible to noise levels, while the neural network was more robust.Conclusion: The machine learning-based approach produces estimates of the perfusion parameters invariant to the noise and artifacts that commonly occur as part of MR acquisition. As a result, better robustness to noise is obtained, when evaluated against the FDA approved software on acute stroke patients and simulated phantom data.

Striatal changes in Parkinson disease: An investigation of morphology, functional connectivity and their relationship to clinical symptoms

We sought to investigate morphological and resting state functional connectivity changes to the striatal nuclei in Parkinson disease (PD) and examine whether changes were associated with measures of clinical function. Striatal nuclei were manually segmented on 3T-T1 weighted MRI scans of 74 PD participants and 27 control subjects, quantitatively analysed for volume, shape and also functional connectivity using functional MRI data. Bilateral caudate nuclei and putamen volumes were significantly reduced in the PD cohort compared to controls. When looking at left and right hemispheres, the PD cohort had significantly smaller left caudate nucleus and right putamen volumes compared to controls. A significant correlation was found between greater atrophy of the caudate nucleus and poorer cognitive function, and between greater atrophy of the putamen and more severe motor symptoms. Resting-state functional MRI analysis revealed altered functional connectivity of the striatal structures in the PD group. This research demonstrates that PD involves atrophic changes to the caudate nucleus and putamen that are linked to clinical dysfunction. Our work reveals important information about a key structure-function relationship in the brain and provides support for caudate nucleus and putamen atrophy as neuroimaging biomeasures in PD.

Facet joint malorientation as a cause of disc degeneration and prolapse in cases with backache: A radiological analysis

Background: Facet tropism is defined as asymmetry between the left and right vertebral facet-joint angles, with one joint having a more sagittal orientation than the other. The goals of the present investigation were to examine the association between facet tropism and disc degeneration as well as disc herniation to determine the relationship between increased sagittal orientation of the facet joint. It is postulated that non-coherent movements of facets on either side leads to an altered biomechanical stress which has to be borne by the anterior structure that is the disc this leading to disc degeneration and earlier prolapse. Methods: Axial and sagittal sections of MRI of the L4 L5 levels of 49 symptomatic adults aged between 20 to 60 years has been taken and their disc degeneration was classified from the T1 and T2 weighted MRI scans and facet tropism was graded as Mild (6-10 degrees), Moderate (11-15 degrees), Severe (>15 degrees). Results: It was observed from our study that the greater the grades of disc degeneration was found in patients with higher degrees of mal-orientation. There is a 5.893 times risk of dis degeneration in the cases of malorientation of the facet joint. There was no significant difference between the male and female population with regard to face tropism as a risk factor for disc degeneration. Conclusion: In our present study the association between the facet tropism as a risk factor for degeneration is positively established. The alteration in the biomechanical forces in the cases of facet tropism thus has led to faster disc degeneration.

Disconnection of hippocampal networks contributes to memory dysfunction in individuals with temporal lobe epilepsy.

A deficit in declarative memory function is common among individuals with temporal lobe epilepsy. The purpose of this study is to evaluate the relationship between the volume of the hippocampus, entorhinal cortex along with the surrounding parahippocampal white matter and memory performance in those with temporal lobe epilepsy. T1 weighted MRI scans were acquired using a 3-D pulse sequence in 50 individuals with temporal lobe epilepsy. Hippocampal and entorhinal cortex volumes were derived by manually tracing consecutive coronal slices aligned perpendicular to the long axis of the hippocampus. In addition, parahippocampal white matter volumes were determined using voxel based morphometry. Finally, declarative memory was assessed using immediate and delayed verbal and visual memory tests from the Wechsler Memory Scale third edition. Significant correlations were seen between right and left hippocampal volumes and delayed verbal memory test scores. In addition, left parahippocampal white matter showed positive correlations with immediate and delayed verbal and visual recall. Furthermore, regression models found that the right hippocampus and left parahippocampal white matter were the best predictors of immediate and delayed verbal and visual memory performance. These results show that a decrease in white matter fibers projecting to the hippocampus may cause a disruption of incoming multi-modal sensory information, contributing to the memory decline seen in individuals with temporal lobe epilepsy.

Preliminary Evidence for Training-Induced Changes of Morphology and Phantom Limb Pain.

The aim of this study was to investigate whether a special prosthetic training in phantom limb pain patients aimed at increasing the functional use of the prosthesis leads to neural morphological plasticity of brain structures and a reduction in phantom limb pain. For chronic pain disorders, it was shown that morphological alterations due to pain might become at least partially reversed by pain therapies. Phantom limb pain is a chronic pain disorder that is frequently followed by neural plasticity of anatomical brain structures. In our study, 10 patients with amputation of the upper limb participated in a two-week training with a myoelectric prosthesis with somatosensory feedback. Grip strength was fed back with electrocutaneous stimulus patterns applied to the stump. Phantom limb pain was assessed before and after the two-week training. Similarly, two T1 weighted MRI scans were conducted for longitudinal thickness analyses of cortical brain structures. As result of this treatment, patients experienced a reduction in phantom limb pain and a gain in prosthesis functionality. Furthermore, we found a change of cortical thickness in small brain areas in the visual stream and the post-central gyrus ipsilateral to the amputation indicating morphological alterations in brain areas involved in vision and pain processing.

Spinal cord infarction: Not to be mistaken for acute transverse myelitis

Objective: Vascular lesions that affect the spinal cord pose a diagnostic challenge as the common symptoms are often seen in a variety of other disorders. This devastating condition has challenging lifelong sequelae. Our two cases highlight that spinal cord lesions can easily be mistaken for acute transverse myelitis and how this impacts on patient management. Methods: Cases: A 14-year-old boy presented with neck pain, headache and difficulty with breathing. He had an initial CT brain plus angiogram, which was normal, followed by an MRI scan demonstrating high signal change in the cord from C2 to C6 thought to be transverse myelitis. Following a lumbar puncture, which did not indicate infection, a diffusion restricted MR scan was carried out and the changes seen were in keeping with anterior cord syndrome. The second patient is a 13-year-old boy who presented with acute lower limb paralysis, which was initially diagnosed as transverse myelitis and treated with steroids. Despite treatment he showed little improvement and had subsequent scans revealing a spinal infarct from T4 to the conus. Both patients received rehabilitation to manage bladder and bowel dysfunction, limb weakness, contractures and the psychological impact of this devastating condition. Results: The investigative aids in diagnosing a spinal infarct are serial scans during the admission especially in circumstances of slow improvement of symptoms, alongside diffusion weighted MRI scans. Not only is the physical management of the condition imperative but also the consideration of the psychological impact on the child and their family. Conclusion: The recognition of this demanding condition is essential to allow for the correct management such as early input from a wide range of health care professionals, who all provide support for the patient and family. When children present with sudden flaccid paralysis, anterior spinal cord infarction should be considered as a differential diagnosis.

White matter integrity in dyskinetic cerebral palsy: Relationship with intelligence quotient and executive function.

BackgroundDyskinetic cerebral palsy (CP) is one of the most disabling motor types of CP and has been classically associated with injury to the basal ganglia and thalamus. Although cognitive dysfunction is common in CP, there is a paucity of published quantitative analyses investigating the relationship between white matter (WM) microstructure and cognition in this CP type.AimsThis study aims (1) to compare brain WM microstructure between people with dyskinetic CP and healthy controls, (2) to identify brain regions where WM microstructure is related to intelligence and (3) to identify brain regions where WM microstructure is related to executive function in people with dyskinetic CP and (4) to identify brain regions where the correlations are different between controls and people with CP in IQ and executive functions.Patients and methodsThirty-three participants with dyskinetic CP (mean ± SD age: 24.42 ± 12.61, 15 female) were age and sex matched with 33 controls. Participants underwent a comprehensive neuropsychological battery to assess intelligence quotient (IQ) and four executive function domains (attentional control, cognitive flexibility, goal setting and information processing). Diffusion weighted MRI scans were acquired at 3T. Voxel-based whole brain groupwise analyses were used to compare fractional anisotropy (FA) and of the CP group to the matched controls using a general lineal model. Further general linear models were used to identify regions where white matter FA correlated with IQ and each of the executive function domains.ResultsWhite matter FA was significantly reduced in the CP group in all cerebral lobes, predominantly in regions connected with the parietal and to a lesser extent the temporal lobes. There was no significant correlation between IQ or any of the four executive function domains and WM microstructure in the control group. In participants with CP, lower IQ was associated with lower FA in all cerebral lobes, predominantly in locations that also showed reduced FA compared to controls. Attentional control, goal setting and information processing did not correlate with WM microstructure in the CP group. Cognitive flexibility was associated with FA in regions known to contain connections with the frontal lobe (such as the superior longitudinal fasciculus and cingulum) as well as regions not known to contain tracts directly connected with the frontal lobe (such as the posterior corona radiata, posterior thalamic radiation, retrolenticular part of internal capsule, tapetum, body and splenium of corpus callosum).ConclusionThe widespread loss in the integrity of WM tissue is mainly located in the parietal lobe and related to IQ in dyskinetic CP. Unexpectedly, executive functions are only related with WM microstructure in regions containing fronto-cortical and posterior cortico-subcortical pathways, and not being specifically related to the state of fronto-striatal pathways which might be due to brain reorganization. Further studies of this nature may improve our understanding of the neurobiological bases of cognitive impairments after early brain insult.

Persistent dysphagia and drowisness following collapse in an alcohol-dependent patient (Answers)

This T2 weighted MRI scan demonstrates a hyperintense trident shaped lesion extending from the pontomedullary junction to the midbrain with peripheral sparing (figure 2 – abnormality indicated by white arrows).

Splenium development and early spoken language in human infants.

The association between developmental trajectories of language-related white matter fiber pathways from 6 to 24months of age and individual differences in language production at 24months of age was investigated. The splenium of the corpus callosum, a fiber pathway projecting through the posterior hub of the default mode network to occipital visual areas, was examined as well as pathways implicated in language function in the mature brain, including the arcuate fasciculi, uncinate fasciculi, and inferior longitudinal fasciculi. The hypothesis that the development of neural circuitry supporting domain-general orienting skills would relate to later language performance was tested in a large sample of typically developing infants. The present study included 77 infants with diffusion weighted MRI scans at 6, 12 and 24months and language assessment at 24months. The rate of change in splenium development varied significantly as a function of language production, such that children with greater change in fractional anisotropy (FA) from 6 to 24months produced more words at 24months. Contrary to findings from older children and adults, significant associations between language production and FA in the arcuate, uncinate, or left inferior longitudinal fasciculi were not observed. The current study highlights the importance of tracing brain development trajectories from infancy to fully elucidate emerging brain-behavior associations while also emphasizing the role of the splenium as a key node in the structural network that supports the acquisition of spoken language.

Abstract CT222: Ferumoxytol enhanced MRI for lymph node staging in genitourinary cancers

Abstract Background: Conventional imaging has limited accuracy in genitourinary (GU) cancer staging. This study examines the utility of ferumoxytol enhanced MRI in lymph node (LN) staging of GU cancers. Methods: This ongoing IRB-approved phase II clinical trial enrolls patients with prostate cancer, renal cell carcinoma, or bladder cancer at high risk for LN metastases. Patients undergo baseline T2 and T2* weighted MRI scans followed by injection of 7.5mg/Kg ferumoxytol. Repeat scans are acquired at 24hr and 48hr post-injection. The criterion for positive LNs was preservation of hyper-intense signal indicating failure to take up ferumoxytol. Validation was by histopathology when available or on clinical grounds, for which LNs that changed size on routine imaging were considered true positives. Results: To date, 13 patients have completed the study. Of 11 prostate cancer patients, one was studied pre-operatively while 10 had suspected therapy failure. Median age and PSA were 65yrs (36-75) and 5.6ng/mL (0.3-201). The other 2 patients had renal cell carcinoma and bladder cancer. Overall, 20 LNs were identified with mean size 1.9cm (0.7-3.8) long axis by 1.3cm (0.6-2.6) short axis. There were 14 true positive LNs, 1 false positive, 1 false negative, and 4 nodes pending validation. Validation was by histopathology for 7 LNs, with 2 nodes pending biopsy, and clinical grounds for 13 LNs, with 2 inconclusive nodes awaiting further validation. Ferumoxytol correctly identified LN status in 9 of 10 patients with validated nodes (Table 1). Conclusions: Ferumoxytol enhanced MRI shows promise in detecting malignant LNs &amp;gt;6mm in GU cancer patients. Since the method involves a conventional MRI unit with off-label use of an FDA-approved agent, it could be widely available. However, further validation is necessary before routine use. Table 1: Preliminary results for LN staging in GU cancer patients using ferumoxytol enhanced MRI SubjectStudy ArmGenderAge (yr)PSA at study initiation (ng/mL)LN numberLN locationsize/long axis (cm)size/short axis (cm)Ferumoxytol positive? 1 = yes, 0 = noResult1prostate cancerM6325.061R ext iliac3.02.61TP2L ext iliac1.30.81TP2prostate cancerM6573.961L RP1.61.41TP2L int iliac3.81.91TP3prostate cancerM6410.491R ext iliac3.00.91pending2L ext iliac1.91.10pending4prostate cancerM742.061L RP1.71.51TP5prostate cancerM642.891R ext iliac1.61.11TP6prostate cancerM650.281L int iliac1.50.81TP7prostate cancerM752.871R int iliac0.70.71TP8prostate cancerM6427.911R common iliac1.71.71inconclusive9prostate cancerM72201.21L RP2.31.70FN10prostate cancerM736.771L int iliac1.51.01TP11prostate cancerM361.351R femoral0.80.81FP2L ext iliac1.51.01inconclusive3R perirectal0.80.61TP12renal cell carcinomaF41N/A1aortocaval2.82.21TP2R RP3.62.31TP3R int iliac2.01.51TP13bladder cancerM59N/A1aortocaval1.51.01TPRP = retroperitoneal, TP = true positive, FN = false negative, FP = false positive, ext = external, int = internal Citation Format: Anna M. Brown, Sandeep Sankineni, Marcelino Bernardo, Dagane Daar, Juanita Weaver, Yolanda McKinney, Anna Couvillon, James L. Gulley, Bradford J. Wood, Peter A. Pinto, William L. Dahut, Ravi Amrit Madan, Peter L. Choyke, Baris Turkbey. Ferumoxytol enhanced MRI for lymph node staging in genitourinary cancers. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT222. doi:10.1158/1538-7445.AM2015-CT222

Ferumoxytol enhanced MRI for lymph node staging in prostate cancer.

208 Background: Conventional imaging methods of lymph node staging in prostate cancer are limited. The goal of this study is to determine the utility of ferumoxytol enhanced MRI in lymph node (LN) staging. Methods: This ongoing IRB-approved clinical trial enrolls prostate cancer patients at high risk for LN metastases. Patients first undergo baseline T2 and T2* weighted MRI scans followed by 7.5mg/Kg ferumoxytol injection. Repeat scans are acquired at 24 hr and 48 hr post-injection. The criterion for positive LNs was hyperintense signal indicating failure to take up ferumoxytol. Validation was determined on clinical grounds or by histopathology when available. Results: To date, 11 patients have completed the study. One patient was examined pre-operatively while the other 10 had suspected therapy failure. Median age and PSA were 65 yrs (36-75) and 5.6ng/dL (0.3-201). Of 16 LNs with median size 1.6 x 1.1cm, 10 were true positives, one was false positive and one was false negative with 4 nodes pending validation. The LN status was correctly identified in 8 of 11 patients [Table]. Conclusions: Ferumoxytol enhanced MRI shows promise in detecting malignant LNs with diameter &gt;6mm in prostate cancer paients. This method is performed in a conventional MRI unit with off-label use of an FDA-approved agent and thus could be widely available. However, further validation is necessary before routine use. Clinical trial information: NCT02141490. [Table: see text]

Morphological differences in the lateral geniculate nucleus associated with dyslexia.

Developmental dyslexia is a common learning disability characterized by normal intelligence but difficulty in skills associated with reading, writing and spelling. One of the most prominent, albeit controversial, theories of dyslexia is the magnocellular theory, which suggests that malfunction of the magnocellular system in the brain is responsible for the behavioral deficits. We sought to test the basis of this theory by directly measuring the lateral geniculate nucleus (LGN), the only location in the brain where the magnocellular and parvocellular streams are spatially disjoint. Using high-resolution proton-density weighted MRI scans, we precisely measured the anatomical boundaries of the LGN in 13 subjects with dyslexia (five female) and 13 controls (three female), all 22–26 years old. The left LGN was significantly smaller in volume in subjects with dyslexia and also differed in shape; no differences were observed in the right LGN. The functional significance of this asymmetry is unknown, but these results are consistent with the magnocellular theory and support theories of dyslexia that involve differences in the early visual system.

Cortical phase changes measured using 7-T MRI in subjects with subjective cognitive impairment, and their association with cognitive function.

Studies have suggested that, in subjects with subjective cognitive impairment (SCI), Alzheimer's disease (AD)-like changes may occur in the brain. Recently, an in vivo study has indicated the potential of ultra-high-field MRI to visualize amyloid-beta (Aβ)-associated changes in the cortex in patients with AD, manifested by a phase shift on T2 *-weighted MRI scans. The main aim of this study was to investigate whether cortical phase shifts on T2 *-weighted images at 7 T in subjects with SCI can be detected, possibly implicating the deposition of Aβ plaques and associated iron. Cognitive tests and T2 *-weighted scans using a 7-T MRI system were performed in 28 patients with AD, 18 subjects with SCI and 27 healthy controls (HCs). Cortical phase shifts were measured. Univariate general linear modeling and linear regression analysis were used to assess the association between diagnosis and cortical phase shift, and between cortical phase shift and the different neuropsychological tests, adjusted for age and gender. The phase shift (mean, 1.19; range, 1.00-1.35) of the entire cortex in AD was higher than in both SCI (mean, 0.85; range, 0.73-0.99; p < 0.001) and HC (mean, 0.94; range, 0.79-1.10; p < 0.001). No AD-like changes, e.g. increased cortical phase shifts, were found in subjects with SCI compared with HCs. In SCI, a significant association was found between memory function (Wechsler Memory Scale, WMS) and cortical phase shift (β = -0.544, p = 0.007). The major finding of this study is that, in subjects with SCI, an increased cortical phase shift measured at high field is associated with a poorer memory performance, although, as a group, subjects with SCI do not show an increased phase shift compared with HCs. This increased cortical phase shift related to memory performance may contribute to the understanding of SCI as it is still unclear whether SCI is a sign of pre-clinical AD. Copyright © 2014 John Wiley & Sons, Ltd.