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To propose a new method of simulating the BOLD contrast using a dynamic, easy to construct and operate, low-cost physical phantom. A structure of thin pipelines passing through a gel volume was used to simulate blood vessels in human tissue. Quantitative T2*, R2* measurements were used to study the signal change of the phantom. BOLD fMRI experiments and analysis were performed to evaluate its potential use as an fMRI simulator. Experimental T2*, R2* measurements showed similar behavior with published references. BOLD contrast was successfully achieved with the proposed method. In addition, there were several proposed parameters, like the angle of the phantom relative to B0, which can easily adjust the signal change and the activation area. Coefficients of variation showed good reproducibility within a month period. Statistical t maps were produced with in-house software for the BOLD measurements. T2*maps and BOLD images confirm the potential use of this phantom as an fMRI simulator and also as a tool for studying sensitivity and specificity of BOLD sequences/algorithms.

BACKGROUND In this study we evaluate the diagnostic accuracy of extraocular muscle volumetry in detecting thyroid eye disease and to compare the results with simple measurements of maximal medial rectus (MR) diameter. METHODS Cross-sectional study that included 47 eyes of 47 patients with thyroid eye disease and 47 healthy controls. Patients underwent slitlamp examination and imaging consisting of computed tomography scans. Image segmentation and volume measurements were performed by 2 independent researchers. Intraobserver and interobserver reliability testing was also conducted. RESULTS Total extraocular muscle volume was 7.31 ± 1.88 cm3 and medial volume was 2.38 ± 0.73 cm3 in the study group. In this group, the maximum measured diameter of the MR was 6.67 ± 0.35 mm. MR volume was statistically associated with maximum MR diameter (r = 9.78; P < 0.001). Both MR volume and maximum MR diameter measurements showed good predictive efficacy as shown using receiver operator characteristic curve analysis. CONCLUSIONS Complications of thyroid eye disease are often sight threatening, and timely diagnosis is crucial for the management of the entity and its sequelae. The results of this study imply that simple measurements of maximum MR diameter are sensitive enough to establish diagnosis.

The study explored associations between hemodynamic changes and psychoemotional status in 32 patients with chronic mild traumatic brain injury (mTBI) and 31 age-matched healthy volunteers. Cerebral blood flow (CBF) and cerebral blood volume (CBV) values were obtained using Dynamic Susceptibility Contrast Magnetic Resonance Imaging in brain regions suspected to play a role in anxiety and depression. Patients were administered self-report measures of anxiety and depression symptoms and underwent neuropsychological assessment. As a group mTBI patients scored significantly below age- and education-adjusted population norms on multiple cognitive domains and reported high rates of anxiety and depression symptomatology. Significantly reduced CBF values were detected in the mTBI group compared to controls in dorsolateral prefrontal areas, putamen, and hippocampus, bilaterally. Within the mTBI group, depressive symptomatology was significantly associated with lower perfusion in the left anterior cingulate gyrus and higher perfusion in the putamen, bilaterally. The latter association was independent from verbal working memory capacity. Moreover, anxiety symptomatology was associated with lower perfusion in the hippocampus (after controlling for verbal episodic memory difficulties). Associations between regional perfusion and psychoemotional scores were specific to depression or anxiety, respectively, and independent of the presence of visible lesions on conventional MRI. Results are discussed in relation to the role of specific limbic and paralimbic regions in the pathogenesis of symptoms of depression and anxiety.

Introduction: Current volume measurement techniques, for the orbit, are time-consuming and involve complex assessments, which prevents their routine clinical use. In this study, we evaluate the applicability and efficacy of stereology and planimetry in orbital volume measurements using magnetic resonance imaging (MRI). Materials and Methods: Prospective imaging study using MRI. Sheep craniums and human subjects were evaluated. Water-filling measurements were performed in animal skulls, as the standard validation technique. Planimetry and stereology techniques were used in each dataset. Intraobserver and interobserver reliability testing were applied. Results: In stereology customization, 1/6 systematic sampling scheme was determined as optimal with acceptable coefficient of error (3.09%) and low measurement time (1.2 min). In sheep craniums, the mean volume measured by water displacement, planimetry, and stereology was 17.81 ± 0.59 cm3, 18.53 ± 0.24 cm3, and 19.19 ± 0.17 cm3, respectively. Planimetric and stereological methods were highly correlated (r = 0.94; P ≈ 0.001). The mean difference of the orbital volume using planimetry and stereology was 0.316 ± 0.168 cm3. In human subjects, using stereology, the mean orbital volume was found to be 19.62 ± 0.2 cm3 with a CE of 3.91 ± 0.15%. Conclusions: The optimized stereological method was found superior to manual planimetry in terms of user effort and time spent. Stereology sampling of 1/6 was successfully applied in human subjects and showed strong correlation with manual planimetry. However, optimized stereological method tended to overestimate the orbital volume by about 1 cc, a considerable limitation to be taken in clinical practice.

To estimate ocular geometry-related inaccuracies of the dosimetric plan in Ru-106 ophthalmic brachytherapy.Thirty patients with intraocular lesions were treated with brachytherapy using a Ru-106 plaque-shell of inner radius of 12 mm. Magnetic resonance imaging was employed to determine the external scleral radius at tumor site and the tumor margins. A mathematical model was developed to determine the distance between the external sclera and the internal surface of the plaque associated with the tangential application of the plaque on the treated eye. Differences in delivered dose to the tumor apex, sclera and tumor margins as derived by considering the default eye-globe of standard size (external sclera radius = 12 mm) against the individual-specific eye globe were determined.The radius of external sclera at the tumor site was found to range between 10.90 and 13.05 mm for the patient cohort studied. When the patient specific eye-globe/tumor geometry is not taken into account, the delivered dose was found to be overestimated by 8.1% ± 4.1% (max = 15.3%) at tumor apex, by 1.5% ± 2.8% (max = 5.7%) at anterior tumor margin, by 16.6% ± 7.5% (max = 36.4%) at posterior tumor margin and 8.1% ± 3.8% (max = 13.2%) at central sclera of eyes with lower than the default radius. The corresponding dose overestimations for eyes with higher than the default radius was 13.5% ± 4.3% (max = 22.3%), 1.5% ± 2.8% (max = 5.7%), 12.6% ± 4.5% (max = 20.0%), and 15.1% ± 5.0% (max = 24.4%).The proposed patient-specific approach for Ru-106 brachytherapy treatment planning may improve dosimetric accuracy. Individualized treatment planning dosimetry may prevent undertreatment of intraocular tumors especially for highly myopic or hyperopic eyes.

Τhe study examined changes in hemodynamics and functional connectivity in patients with systemic lupus erythematosus (SLE) with or without neuropsychiatric manifestations.Participants were 44 patients with neuropsychiatric SLE (NPSLE), 20 SLE patients without such manifestations (non-NPSLE), and 35 healthy controls. Resting-state functional MRI (rs-fMRI) was used to obtain whole-brain maps of (a) perfusion dynamics derived through time shift analysis (TSA), (b) regional functional connectivity (intrinsic connectivity contrast (ICC) coefficients), and (c) hemodynamic-connectivity coupling. Group differences were assessed through independent samples t-tests, and correlations of rs-fMRI indices with clinical variables and neuropsychological test scores were, also, computed.Compared to HC, NPSLE patients demonstrated intrinsic hypoconnectivity of anterior Default Mode Network (DMN) and hyperconnectivity of posterior DMN components. These changes were paralleled by elevated hemodynamic lag. In NPSLE, cognitive performance was positively related to higher intrinsic connectivity in these regions, and to higher connectivity-hemodynamic coupling in posterior DMN components. Uncoupling between hemodynamics and connectivity in the posterior DMN was associated with worse task performance. Non-NPSLE patients displayed hyperconnectivity in posterior DMN and sensorimotor regions paralleled by relatively increased hemodynamic lag.Adaptation of regional brain function to hemodynamic changes in NPSLE may involve locally decreased or locally increased intrinsic connectivity (which can be beneficial for cognitive function). This process may also involve elevated coupling of hemodynamics with functional connectivity (beneficial for cognitive performance) or uncoupling, which may be detrimental for the cognitive skills of NPSLE patients.

Background Although diffusely abnormal white matter (DAWM) is commonly seen in multiple sclerosis (MS), it is rarely considered in clinical/imaging studies. Purpose To evaluate quantitative markers of microstructural changes in DAWM of patients with clinically isolated syndrome (CIS) and relapsing-remitting MS (RR-MS) in relation to MS lesions and degree of neurocognitive impairment, by using a multi-echo spin echo (MESE) Proton Density PD-to-T2 sequence. Study type Prospective, cross-sectional. Population Thirty-seven RR-MS patients, 33 CIS patients, and 52 healthy controls. Field strength/sequence 1.5 T/T1-, T2-weighted, fluid-attenuated inversion recovery, and MESE sequences. Assessment Long T2, short T2, and myelin water fraction (MWF) values were estimated as indices of intra/extracellular water content and myelin content, respectively, in DAWM, posterior periventricular normal appearing white matter (NAWM), and focal MS lesions, classified according to their signal intensity on T1 sequences. Patients were, also, administered a battery of neuropsychological tests. Statistical tests Comparisons of T2 and MWF values in DAWM, NAWM, and MS lesions were examined, using two-way mixed analyses of variance. Associations of Grooved Pegboard performance with T2 and MWF values in DAWM and NAWM were assessed using Pearson correlation coefficients. Results T2 and MWF values of DAWM were intermediate between the respective values of NAWM and T1 hypointense focal lesions, while there was no difference between the respective values of DAWM and T1-isointense lesions. T2 values in DAWM were strongly associated with visuomotor performance in CIS patients. Data conclusion Intra/extracellular water and myelin water content of DAWM are similar to those of T1-isointense lesions and predict visuomotor performance in CIS patients. Level of evidence 2 TECHNICAL EFFICACY: Stage 2.

This study aims to examine a time-extended dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) protocol and report a comparative study with three different pharmacokinetic (PK) models, for accurate determination of subtle blood–brain barrier (BBB) disruption in patients with multiple sclerosis (MS). This time-extended DCE-MRI perfusion protocol, called Snaps, was applied on 24 active demyelinating lesions of 12 MS patients. Statistical analysis was performed for both protocols through three different PK models. The Snaps protocol achieved triple the window time of perfusion observation by extending the magnetic resonance acquisition time by less than 2 min on average for all patients. In addition, the statistical analysis in terms of adj-R 2 goodness of fit demonstrated that the Snaps protocol outperformed the conventional DCE-MRI protocol by detecting 49% more pixels on average. The exclusive pixels identified from the Snaps protocol lie in the low k trans range, potentially reflecting areas with subtle BBB disruption. Finally, the extended Tofts model was found to have the highest fitting accuracy for both analyzed protocols. The previously proposed time-extended DCE protocol, called Snaps, provides additional temporal perfusion information at the expense of a minimal extension of the conventional DCE acquisition time.

The study examined the hypothesis that hypoperfusion in brain areas known to be involved in emotional disturbances in primary psychiatric disorders is also linked to emotional difficulties in systemic lupus erythematosus (SLE) and that these are not secondary to the physical and social burden incurred by the disease. Nineteen SLE patients without overt neuropsychiatric manifestations (non-NPSLE), 31 NPSLE patients, and 23 healthy controls were examined. Dynamic susceptibility contrast MRI was used and cerebral blood flow and cerebral blood volume values were estimated in six manually selected regions of interest of brain regions suspected to play a role in anxiety and depression (dorsolateral prefrontal cortex, ventromedial prefrontal cortex, anterior cingulate cortex, hippocampi, caudate nuclei and putamen). NPSLE patients reported high rates of anxiety and depression symptomatology. Significantly reduced cerebral blood flow and cerebral blood volume values were detected in the NPSLE group compared to healthy controls in the dorsolateral prefrontal cortex and ventromedial prefrontal cortex, bilaterally. Within the NPSLE group, anxiety symptomatology was significantly associated with lower perfusion in frontostriatal regions and in the right anterior cingulate gyrus. Importantly, the latter associations appeared to be specific to anxiety symptoms, as they persisted after controlling for depression symptomatology and independent of the presence of visible lesions on conventional MRI. In conclusion, hypoperfusion in specific limbic and frontostriatal regions is associated with more severe anxiety symptoms in the context of widespread haemodynamic disturbances in NPSLE.

BACKGROUND According to the retrogenesis hypothesis, the rate of age-related changes in white matter (WM) myelin content varies between early myelinating (parietal, occipital) and late myelinating (prefrontal, lateral-posterior temporal) areas. The multiecho spin echo (MESE), PD-to-T2 -weighted sequence provides an index of myelin content (myelin water fraction [MWF]) derived from measurements of myelin water (via the short T2 component [10-50 msec]) and intra- and extracellular water (via the long T2 component [>50-200 msec]). PURPOSE To assess the shape and regional variations in the rate of age-related myelin and water content changes in deep WM regions using the MESE sequence. STUDY TYPE Prospective, cross-sectional. POPULATION In all, 90 healthy adults aged 22-81 years. FIELD STRENGTH/SEQUENCE 1.5T/ T1 w, T2 w, fluid attenuated inversion recovery (FLAIR), MESE sequences. ASSESSMENT Short T2 , long T2 , and MWF values were measured in prefrontal, parietal, lateral-posterior temporal, and occipital normal-appearing WM (NAWM) areas. STATISTICAL TESTS Linear and quadratic effects of age on long T2 and MWF were assessed through regression analyses. Regional variations in the effect of age on long T2 and MWF values at both the individual and group level were examined, using regression and analysis of covariance (ANCOVA) analyses, respectively, controlling for total WM volume. RESULTS The rate of age-related changes in long T2 and MWF was higher for older persons and a significant increase or decline, respectively, was first noted at 60-69 years (P

Computer-aided diagnosis systems aim to assist clinicians in the early identification of abnormal signs in order to optimize the interpretation of medical images and increase diagnostic precision. Multiple sclerosis (MS) and clinically isolated syndrome (CIS) are chronic inflammatory, demyelinating diseases affecting the central nervous system. Recent advances in deep learning (DL) techniques have led to novel computational paradigms in MS and CIS imaging designed for automatic segmentation and detection of areas of interest and automatic classification of anatomic structures, as well as optimization of neuroimaging protocols. To this end, there are several publications presenting artificial intelligence-based predictive models aiming to increase diagnostic accuracy and to facilitate optimal clinical management in patients diagnosed with MS and/or CIS. The current study presents a thorough review covering DL techniques that have been applied in MS and CIS during recent years, shedding light on their current advances and limitations.

In order to inform the debate whether cortical areas related to action observation provide a pragmatic or a semantic representation of goal-directed actions, we performed 2 functional magnetic resonance imaging (fMRI) experiments in humans. The first experiment, involving observation of aimless arm movements, resulted in activation of most of the components known to support action execution and action observation. Given the absence of a target/goal in this experiment and the activation of parieto-premotor cortical areas, which were associated in the past with direction, amplitude, and velocity of movement of biological effectors, our findings suggest that during action observation we could be monitoring movement kinematics. With the second, double dissociation fMRI experiment, we revealed the components of the observation-related cortical network affected by 1) actions that have the same target/goal but different reaching and grasping kinematics and 2) actions that have very similar kinematics but different targets/goals. We found that certain areas related to action observation, including the mirror neuron ones, are informed about movement kinematics and/or target identity, hence providing a pragmatic rather than a semantic representation of goal-directed actions. Overall, our findings support a process-driven simulation-like mechanism of action understanding, in agreement with the theory of motor cognition, and question motor theories of action concept processing.

To propose a new method of simulating the BOLD contrast using a dynamic, easy to construct and operate, low-cost physical phantom.A structure of thin pipelines passing through a gel volume was used to simulate blood vessels in human tissue. Quantitative T2*, R2* measurements were used to study the signal change of the phantom. BOLD fMRI experiments and analysis were performed to evaluate its potential use as an fMRI simulator.Experimental T2*, R2* measurements showed similar behavior with published references. BOLD contrast was successfully achieved with the proposed method. In addition, there were several proposed parameters, like the angle of the phantom relative to B0, which can easily adjust the signal change and the activation area. Coefficients of variation showed good reproducibility within a month period. Statistical t maps were produced with in-house software for the BOLD measurements.T2*maps and BOLD images confirm the potential use of this phantom as an fMRI simulator and also as a tool for studying sensitivity and specificity of BOLD sequences/algorithms.

Blood Oxygen Level Dependent (BOLD) is a commonly-used MR imaging technique in studying brain function. The BOLD signal can be strongly affected by specific sequence parameters, especially in small field strengths. Previous small-scale studies have investigated the effect of TE on BOLD contrast. This study evaluates the dependence of fMRI results on echo time (TE) during concurrent activation of the visual and motor cortex at 1.5 T in a larger sample of 21 healthy volunteers. The experiment was repeated using two different TE values (50 and 70 ms) in counterbalanced order. Furthermore, T2* measurements of the gray matter were performed. Results indicated that both peak beta value and number of voxels were significantly higher using TE = 70 than TE = 50 ms in primary motor, primary somatosensory and supplementary motor cortices (p &lt, 0.007). In addition, the amplitude of activation in visual cortices and the dorsal premotor area was also higher using TE = 70 ms (p &lt, 0.001). Gray matter T2* of the corresponding areas did not vary significantly. In conclusion, the optimal TE value (among the two studied) for visual and motor activity is 70 ms affecting both the amplitude and extent of regional hemodynamic activation.

Cognitive disturbances occur in patients with Relapsing Remitting Multiple Sclerosis (RR-MS) and Clinically Isolated Syndrome (CIS). The Multi-Echo-Spin-Echo (MESE) T2-weighted sequence quantifies demyelination, the pathological hallmark of MS, but has not been used for the documentation of the potential relationship between anatomically specific demyelinating changes and cognitive impairment in MS.To identify markers of regional demyelination in patients with RR-MS and CIS in relation to clinical variables and severity of cognitive impairment.37 RR-MS patients, 39 CIS patients and 52 healthy controls (HC) were examined using the MESE sequence. Long T2 and myelin water fraction (MWF) values were measured, serving as indices of intra/extracellular water content and myelin content, respectively, in focal white matter lesions and 12 normal appearing white matter (NAWM) areas of the patients and HC. A comprehensive neuropsychological assessment was administered to all patients.RR-MS patients showed widespread long T2 increases and MWF reductions in NAWM, compared to the respective values of HC (p0.001), which correlated with total lesion volume. Among RR-MS patients illness duration correlated negatively with MWF in right hemisphere frontal and periventricular NAWM areas (and positively with corresponding long T2 values). MWF values were lower in the CIS, as compared to the HC group, in the temporal, frontal and periventricular NAWM areas. Focal demyelinating lesions displayed variable higher T2 and lower MWF values, compared to NAWM, closely corresponding to their intensity on T1 sequences. Reduced MWF values and increased long T2 values in right periventricular NAWM were significantly associated with poor visuomotor performance.The MESE sequence affords accurate estimation of myelin and water content in NAWM and focal lesions in RR-MS and CIS patients, by means of the MWF and long T2 values, respectively, providing a sensitive index of demyelination associated with visuomotor deficits.

Purpose Brachytherapy with Ru-106 is widely used for the treatment of intraocular tumors, and its efficacy depends on the accuracy of radioactive plaque placement. Ru-106 plaques are MRI incompatible and create severe metal artifacts on conventional CT scans. Dual-energy CT scans (DECT) may be used to suppress such artifacts. This study examines the possibility of creating fusion images from MRI scans (preoperatively) and DECT scans (with the plaque in place) as a tool for confirming the anatomic accuracy of plaque placement. Methods and Materials Six patients with intraocular lesions (5 with choroidal melanoma and 1 with a retinal vasoproliferative lesion) were included. Fusion images of preoperative MRI scans and DECT scans with the plaque in place were created with the Demo version of the ImFusion suite (ImFusion GmbH, Munchen Germany). Clearance margins between the tumor and plaque edge in axial, transverse, and coronal planes as well as the elevation of the posterior plaque edge from the sclera were recorded and associated with the location of the lesion. Results Plaque-tumor clearance margins for transverse, sagittal, and coronal planes were higher for anteriorly located lesions (5.13 mm ± 0.11 [5.0–5.2], 5.10 mm ± 0.26 [4.9–5.4], and 5.33 mm ± 0.45 [4.9–5.8] respectively) than for posteriorly located lesions (4.16 mm ± 1.44 [2.5–5.1], 4.13 mm ± 1.42 [2.5–5.1], and 4.2 mm ± 1.21 [2.8–5.0], respectively). The elevation of the posterior plaque edge from the sclera was 0.33 mm ± 0.28 [0–0.5] and 0.63 mm ± 0.60 [0.7–1.2] for posterior and anterior lesions, respectively. Conclusions Fusion images between DECT and MRI scans may be used as a tool to confirm the accuracy of Ru-106 plaque placement in relation with the intraocular tumors in ophthalmic brachytherapy.

Objective: To measure the effective orbital volume (EOV) from magnetic resonance images, and investigate its relationship with axial length (AL) in those parameters. Methods: Cross-sectional, 3D-MRI study. 54 eyes of 54 patients (25 males) were included in this work. Patient weight, height and head circumference were also measured. Orbital and eyeball volumes were calculated after image segmentation. The difference between those values volume was assessed, estimating the EOV for each eye. Results: Mean eyeball volume was 7.83 ± 2.27 mm3, mean orbital volume 26.81 ± 0.59 mm3 and EOV 21.64 ± 0.19 mm3. The orbital volume was significantly higher in the male group (Wilcoxon signed-rank tests Z=-1.51, p

To evaluate the applicability of stereology and planimetry in orbital volume measurements using computed tomography (CT) and to compare the results between the two measurements. Experimental study using sheep craniums for CT imaging. Water filling measurements were performed, as the validation technique. Quantification techniques were also evaluated in five human subjects. To examine the proportion of agreement among measurements, we tested intra- and inter-observer agreement. For stereology customization, a 1/8 systematic sampling scheme was considered as optimal; this resulted in a low coefficient of error (2.59 %) and low measurement time (1.9 mins). In sheep craniums, mean volume measured by water displacement, planimetry and stereology was 17.81 ± 0.59 cm3, 17.87 ± 0.68 cm3 and 17.54 ± 0.49 cm3, respectively. Total volumes, obtained by stereology, were highly correlated with the water-filling method (r=0.893; p = 0.001) and a paired t-test showed significant difference between methods (t=3.047; p = 0.014). Planimetry results displayed a high correlation with the water-filling method (r=0.957; p ≈ 0.001) but no statistically significant difference was found (p = 0.154). Mean difference using planimetry and stereology was 0.332 ± 0.322 cm3. In human subjects, using stereology, the estimated volume ranged between 18.57 cm3 and 19.27 cm3, and the mean orbital volume was 19.05 ± 0.50 cm3 with CE=3.75 ± 0.16 %. Mean measure time was 2.1 ± 0.1 mins. Stereological measurements were superior to manual planimetry in terms of user effort and time spent. Stereology sampling of 1/8 was successfully applied in human subjects and yielded a strong correlation with manual planimetry. • Stereology can be applied to measure the orbital volume using computed tomography. • Stereological measurements display high correlation with gold standard planimetry and combine low coefficient of error (2.59%) with low measurement time (1.9 min). • Stereology is superior in terms of user effort and time spent.

PURPOSE: Posterior staphyloma is an ocular complication associated with high myopia and reflects degenerative changes on the sclera. Its morphology is associated with chorioretinal atrophy and myopic maculopathy. The purpose of this study was to validate the efficacy of optical coherence tomography (OCT) in providing a simple estimation of the staphyloma pattern. MATERIALS AND METHODS: Observational case-series study of high myopic patients with posterior staphylomas. Patients were examined using the star scan pattern OCT in different radial planes. Three-dimensional (3D) magnetic resonance tomography was also performed to visualize the anatomical characteristics of the posterior pole. 3D-segmentation and curvature analysis were also performed. RESULTS: Eight patients were totally enrolled in this pilot study. Our study pool consisted of 2 wide macular staphylomas, 2 narrow macular staphylomas, and 4 barrel-shaped staphylomas. Our preliminary results revealed that patients displayed mirror-image distortion in the steeper staphyloma axis. In the barrel-shaped subtype, no image distortion was displayed in any plane. CONCLUSION: We estimated the axis of the smaller base curvature by noting the distortion pattern in the different radial axis. The recognition of pathologic axial myopia is important since there is a risk of permanent vision loss from vision to threatening sequelae.

Objective The aim of the present study is to provide further insight into semantic processing in Working Memory (WM) in two amnesic patients with extensive medial temporal lobe (MTL) by adopting a short length word-lists recall task. Background It is still unclear whether the medial temporal lobe structures and especially the hippocampus is recruited in semantic processing in the context of WM. Materials & methods Two severely amnesic patients with extensive MTL damage due to herpes simplex encephalitis (HSE) and a control group ( n = 36) underwent an experimental task involving the immediate free recall of 9 word-lists in three different conditions: 1. semantically related words clustered according to semantic category (SRC), 2. semantically related words non-clustered (SRnC), 3. semantically unrelated words (SU). Additionally, standard cognitive measures were administered [Digit Span Forward & Backward, Greek Verbal Learning Test (GVRT), Verbal Fluency Test (VFT), Logical Memory I & II (LM-I & LM-II) of Wechsler Memory Scale (WMS)]. Results Both patients obtained normal performance in WM tests (Digit Span Forward & Backward), but were impaired in GVRT, VFT, LM-I and LM-II. With regard to the word-list task, the number of words recalled by both patients’ did not differ from controls. However, semantic facilitation effects were not recorded in patients’ performance for the SRC and SRnC conditions (SRC = SRnR = SU), unlike controls (SRC > SRnC > SU). Conclusions Our results suggest that the effects of semantic facilitation in short length word-lists recall are diminished to a certain degree in HSE patients that suffer from MTL damage.

Purpose To investigate the potential of dual energy CT (DECT) to suppress metal artifacts and accurately depict episcleral brachytherapy Ru-106 plaques after surgical placement. Methods An anthropomorphic phantom simulating the adult head after surgical placement of a Ru-106 plaque was employed. Nine DECT acquisition protocols for orbital imaging were applied. Monochromatic 140 keV images were generated using iterative reconstruction and an available metal artifact reduction algorithm. Generated image datasets were graded by four observers regarding the ability to accurate demarcate the Ru-106 plaque. Objective image quality and visual grading analysis (VGA) was performed to compare different acquisition protocols. The DECT imaging protocol which allowed accurate plaque demarcation at minimum exposure was identified. The eye-lens dose from orbital DECT, with and without the use of radioprotective bismuth eye-shields, was determined using Monte Carlo methods. Results All DECT acquisition protocols were judged to allow clear demarcation of the plaque borders despite some moderate streaking/shading artifacts. The differences between mean observers’ VGA scores for the 9 DECT imaging protocols were not statistically significant (p > 0.05). The eye-lens dose from the proposed low-exposure DECT protocol was found to be 20.1 and 22.8 mGy for the treated and the healthy eye, respectively. Bismuth shielding was found to accomplish >40% reduction in eye-lens dose without inducing shielding-related artifacts that obscure plaque delineation. Conclusions DECT imaging of orbits after Ru-106 plaque positioning for ocular brachytherapy was found to allow artifact-free delineation of plaque margins at relatively low patient exposure, providing the potential for post-surgery plaque position verification.

Myopia is a major cause of visual impairment and its prevalence is increasing globally at an alarming rate. High pathologic myopia is described as myopia with associated degenerative changes in the...

In this study we explored the robustness of machine learning algorithms for the classification of Neuropsychiatric systemic lupus erythematosus (NPSLE) patients and healthy controls using resting-state fMRI functional connectivity matrices. NPSLE, which is driven by systemic autoimmune inflammation in the context of lupus, involves a wide range of focal and diffuse central and peripheral nervous system symptoms and poses significant diagnostic challenges. Machine learning applications on clinical data may enhance the existing workflow for NPSLE classification as there is no established method of applying neuroimaging data to the diagnosis of NPSLE. Feature selection methods were applied prior to the classification process in order to perform the classification process on a lower dimension feature space. The Connectivity Matrix used consisted of pairwise regional functional associations of the fMRI signals (ROI to ROI correlations) within each of three predetermined brain networks in 41 NPSLE patients and 31 healthy control subjects. Support Vector Machines (SVM) was utilized in the final model. Results were evaluated using a nested cross validation methodology to prevent overfitting, and enhance generalization. Regions of Interest (ROI's) that contributed most in the final model were: Right Inferior Temporal, Thalamus, Left Angular Gyrus, Right Precuneus, Left Primary Motor Cortex, SMA, Left and Right Primary Motor Cortex. With a final F1 score of up to 77%, the results demonstrate the potential for the future implementation of similar methods in the diagnosis of NPSLE.

Background Cognitive event-related potentials (ERPs) have been previously correlated with T2 lesion load (Τ2LL) in patients with multiple sclerosis (MS). It is currently unknown, however, whether ERPs also correlate with brain atrophy or the presence of T1 hypointense lesions (“black holes”) which reflect tissue destruction and axonal loss. The primary aim of the current study is to explore the effect of neuroradiological parameters such as brain atrophy, T1 and T2 lesion load on auditory ERPs in MS patients. In addition, we correlated cognitive impairment with neurophysiological (ERP) and neuroradiological (MRI) variables and investigated whether a combination of ERP and MRI parameters is capable of distinguishing patients suffering from secondary progressive (SP), primary progressive (PP) and relapsing-remitting (RR) MS. Materials and methods The study sample consisted of fifty nine MS patients (mean age±SD: 37.82±1.38 years; average disease duration: 6.76±5.3 years) and twenty six age-matched controls (mean age±SD: 41.42±15.39 years). The patients’ EDSS and NRS scores were 3.77±2.14 (range: 1–7.5) and 75.88±11.99 (range: 42–94) respectively. ERPs were recorded using the auditory “odd-ball” paradigm. T1 and T2 lesions were automatically segmented using an edge-finding tool and total lesion volumes were calculated. MRI measures of brain atrophy included third ventricle width (THIRDVW) and the ratio of mid-sagittal corpus callosum area to the mid-sagittal intracranial skull surface area (CC/MISS). Statistical analysis was performed using multiple regression, principal component (PCA) and discriminant analysis. Results T1 lesion load emerged as the most significant predictor of P300 and N200 latency. The rest of the endogenous ERPs parameters (P300 amplitude, N200 amplitude) were not significantly correlated with the MRI variables. PCA of pooled neuroradiological and neurophysiological markers suggested that four components accounted for 64.6% of the total variability. Discriminant analysis based on ERP & MRI markers classified correctly 79.63% of patients in RR, PP and SP subgroups. Conclusion T1 lesion load is the most significant MRI correlate of auditory ERPs in MS patients. Importantly, ERPs in combination with MRI variables can be usefully employed for distinguishing patients with different subtypes of MS.

Background Posterior reversible encephalopathy syndrome (PRES) has only rarely been reported in patients with multiple sclerosis (MS). Methods Case report of a patient with relapsing remitting (RR) MS patient on interferon (INF) treatment, who developed posterior fossa PRES. Results A 46-year-old male diagnosed with RR MS in 2010 was placed on INF beta-1a therapy. He remained in clinical remission for seven years. He then presented with headache of one month duration and worsening upper extremity ataxia. Cranial MRI revealed two new enhancing cerebellar lesions (one with tumefactive features). Within the next 10 days the patient developed severe holocephalic headache, vomiting, altered consciousness and gait instability. Urgent brain MRI revealed diffuse hyperintense lesions in T2WI and FLAIR sequences in bilateral cerebellar hemispheres and the right thalamus, with marked swelling, increased diffusivity indicative of vasogenic edema and patchy-nodular enhancement, while smaller lesions were also found in posterior temporal, parietal and occipital lobes. Severely elevated blood pressure was noted. Treatment with hypertonic agents, esmolol drip and IV steroids was instituted, resulting in remarkable improvement within the next several days. Repeat MRI showed almost complete resolution of the cerebellar lesions. Interferon beta was discontinued and blood pressure remained well controlled. Conclusions Patients with RR MS on IFN beta therapy can develop PRES via the combination of hypertension and endothelial dysfunction by IFN, even when stable on this treatment. Neurologists should be keen to differentiate the appearance of PRES lesions from those of fulminant MS relapse, opportunistic infections or malignancy.

According to the retrogenesis hypothesis, the rate of age-related changes in white matter (WM) myelin content varies between early myelinating (parietal, occipital) and late myelinating (prefrontal, lateral-posterior temporal) areas. The multiecho spin echo (MESE), PD-to-TTo assess the shape and regional variations in the rate of age-related myelin and water content changes in deep WM regions using the MESE sequence.Prospective, cross-sectional.In all, 90 healthy adults aged 22-81 years.1.5T/ TShort TLinear and quadratic effects of age on long TThe rate of age-related changes in long TSignificant age-related reductions in myelin content were closely followed by corresponding increases in intra- and extracellular water content. These changes were more pronounced among elderly people and followed an anterior-posterior pattern.2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1393-1404.

Quantitative MRI plays a central role in the precision management of cancer. Regarding breast cancer (BRCA) patients, DCE-MRI imaging biomarkers (IBs) have shown promising results both in clinical trials and clinical practice. The advancements in the field of radiomics offer more opportunities for defining disease-specific imaging biomarkers for screening, diagnosis and therapy assessment. In this paper we present a study investigating the role of radiomics in predicting breast-cancer therapy response in the neoadjuvant setting. A temporal radiomics approach is proposed for predicting breast cancer therapy response in the neoadjuvant setting on a public cohort of 35 patients with histologically-proven breast cancer of stage II/III with DCEMRI data available before treatment, after the first cycle and before the end of treatment. The results based on 57 radiomics features indicate that neoadjuvant chemotherapy (NAC) treatment outcome can be predicted both at baseline and right after the first NAC cycle. Our analyses, found that the best predictors were the median and size-zone non-uniformity normalized calculated from the wavelet decomposition of level 2 of the baseline and the first follow-up exam, achieving an AUROC of 80.80% and 81.34% respectively. These encouraging preliminary results call for more relevant research investigating the role of temporal radiomics in predicting NAC outcome towards more personalized therapy planning.

Accurate determination of disease activity by detection of the acute, inflammatory Multiple Sclerosis (MS) lesions, with blood brain barrier disruption and contrast enhancement is critical for clinicians because it affects diagnosis and treatment. In this work, a new Dynamic Contrast Enhanced (DCE) protocol was investigated in conjunction with different pharmacokinetic (PK) models in order to define a well-designed workflow for DCE MRI analysis of acute, active MS lesions. This time extended protocol, achieved to double the perfusion time by extending the overall MRI acquisition less than two minutes. Four patients with early relapsing remitting multiple sclerosis were analyzed with two different DCE protocols and three PK models. The statistical comparison of the different approaches, including biomarkers and metrics of goodness of fit, showed that extension of the DCE imaging time, the so called ‘Snaps’ protocol, combined with the extended Tofts model PK analysis, achieved the characterization of 15% more pixels into acute, active MS lesions in terms of fitting low enhancement pixels, and resulted in more accurate detection of the active lesion area. To this end, a novel DCE acquisition framework is presented herein that achieved to double the perfusion time by loading the protocol duration less than two minutes, and as a result a better characterization of active MS lesions in terms of fitting accuracy and size of the lesion was achieved.

Objective Abnormalities in regional or global cerebral perfusion have been reported in SLE but their value in distinguishing lupus from non-lupus related diffuse neuropsychiatric events has not been determined. We examined whether the addition of dynamic susceptibility-contrast-enhanced T2*-weighted perfusion MRI (DSC-MRI), a non-invasive assessment of brain haemodynamic status, to the standard MRI examination suggested by the EULAR recommendations, may be of added value in the clinical diagnosis and attribution of neuropsychiatric SLE (NPSLE). Patients and methods Seventy-six SLE patients (53 NPSLE, 23 non-NPSLE) and 31 healthy controls underwent conventional MRI (cMRI) and DSC-MRI. Attribution of NPSLE to lupus (primary NPSLE: n=37) or not (n=16) was based on multidisciplinary assessment including cMRI results and response to treatment. Cerebral blood volume (CBV) and cerebral blood flow (CBF) values were estimated in 18 normal-appearing white matter (NAWM) and deep grey matter (NADGM) areas. Perfusion differences among subgroups and their diagnostic utility were assessed using Analysis of Variance, Receiver Operating Characteristics, and Binary Logistic Regression analysis. Results The most common manifestations were mood disorder, cognitive disorder and headache. The most common manifestations were mood disorder, cognitive disorder and headache. Primary NPSLE patients had lower cerebral blood flow and volume in several NAWM areas compared to controls (p Conclusion Primary NPSLE is characterised by significant hypoperfusion in white matter and deep grey matter areas that appear normal on conventional MRI sequences. Addition of cerebral blood flow in the semioval centre to conventional MRI techniques described in the EULAR NPSLE recommendations improves the diagnosis of primary NPSLE.

Existing indices of white matter integrity such as fractional anisotropy and magnetization transfer ratio may not provide optimal specificity to myelin content. In contrast, myelin water fraction (MWF) derived from the multiecho TThe goal of the present study was to identify markers of regional demyelination in patients with probable Alzheimer's disease (AD) and mild cognitive impairment (MCI) in relation to age and severity of neuropsychiatric impairment.The sample included patients diagnosed with probable AD (n = 25) or MCI (n = 43), and cognitively intact elderly controls (n = 33).Long TAD patients displayed higher age-adjusted long and short TAge-related demyelination is associated with memory impairment (especially in prodromal dementia states) and symptoms of depression in an anatomically specific manner.1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1359-1372.

Background The management of “aggressive” and “highly-active” relapsing-remitting multiple sclerosis remains problematic. Although a number of highly efficacious agents are currently available, the optimal timing of their use and the balancing between efficacy and immediate and long-term consequences are still a matter of conjecture. Methods We describe the clinical, radiological and immunological profile of three multiple sclerosis patients with persistent clinical and radiological disease activity under fingolimod treatment. After fingolimod cessation patients demonstrated severe disease exacerbation and were successfully treated with alemtuzumab. Results All patients experienced significant improvement after the administration of alemtuzumab and achieved no evidence of disease activity status that persisted after a median of 19 months of follow-up (range: 17–25 months). Confirmed disability improvement was achieved in all cases. Quantitative MRI data demonstrated a reduction of the T2 lesion load in 2 out of 3 patients and complete abrogation of inflammatory activity in all patients after the administration of alemtuzumab. Α patient presented a previously unreported, persistent lymphocytosis after alemtuzumab administration, that was not associated with infectious, lymphoproliferative or autoimmune diseases and had no apparent clinical implications. Conclusions Alemtuzumab appears to be an effective and safe short-term therapeutic option both as a rescue therapy for the disease flare-up associated with fingolimod withdrawal, as well as for the reversal of the deteriorating course observed in patients who fail treatment with fingolimod.

AIM To evaluate the relative and combined utility of 99mTc-tetrofosmin (99mTc-TF) brain single-photon-emission computed tomography (SPECT) and dynamic susceptibility contrast (DSC) perfusion magnetic resonance imaging (MRI) in grading brain gliomas. MATERIALS AND METHODS Thirty-six patients with clinically suspected brain tumours were assessed by 99mTc-TF SPECT and DSC-MRI. Brain tumour malignancy was confirmed in all patients at histopathology. On both techniques brain lesions were evaluated via visual and semi-quantitative analysis methods (deriving tetrofosmin index [T-index] and relative cerebral blood volume [rCBV] ratios, respectively). RESULTS 99mTc-TF SPECT showed abnormally elevated tracer uptake in 31/36 patients whereas MRI detected the brain tumour in all patients. Optimal cut-off values of each index for discriminating between low- and high-grade gliomas were obtained through receiver operating characteristic (ROC) analyses. A T-index cut-off of 6.35 ensured 82% sensitivity and 71% specificity for discriminating between high- and low-grade gliomas, whereas a relative rCBV ratio cut-off of 1.80 achieved 91% sensitivity and 100% specificity. Requiring a positive result on either technique to characterise a high-grade glioma was associated with similar specificity and slightly increased sensitivity. CONCLUSION Both imaging techniques, 99mTF SPECT and DSC MRI, may provide complementary indices of tumour grade and have an independent diagnostic value for high-risk tumours.

Background and purpose To investigate the relation between hemodynamic measurements and memory function in patients with clinically isolated syndrome (CIS). Methods Forty CIS patients were administered tests of verbal short-term/working memory and passage learning. Using dynamic susceptibility contrast MRI cerebral blood volume (CBV), cerebral blood flow and mean transit time values were estimated in 20 cerebral regions of interest, placed in normal appearing white matter (NAWM) and normal appearing deep gray matter structures, bilaterally. Results CIS patients showed significantly impaired scores on working memory and secondary verbal memory that correlated inversely with elevated CBV values in the left frontal and periventricular NAWM, thalamus, right caudate and corpus callosum. Conclusions Verbal memory in CIS correlates inversely with elevated CBV values of brain structures involved in memory. As these hemodynamic changes, detected in CIS, are indicative of inflammation, the observed cognitive disturbances may relate to widespread brain inflammatory processes that prevail in early multiple sclerosis.