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Objective: Temporal lobe epilepsy (TLE) accompanied by hippocampal sclerosis (HS) is the most common type of focal epilepsies. Hemispheric asymmetry is a feature of brain organization in both invertebrates and vertebrates and may be the key to some neurodegenerative diseases. In this context, we aimed to investigate the volumetric asymmetry difference in cerebral structures between TLE patients and the healthy control group, based on magnetic resonance imaging (MRI) data that may be used as a new neuroimaging marker for TLE cases. Patients and Methods: In this retrospective study the cranial MRIs of fourteen clinically manifesting, radiologically HS-identified, and diagnosed TLE patients and fourteen healthy individuals from the Radiology Department of Yeditepe University Hospital were evaluated. Volume measurements and asymmetry index (AI) calculations in the total brain, hippocampus, temporal lobe, amygdala, thalamus, nucleus accumbens (NAc), premotor cortex, primary and somatosensory cortices were performed using the medical NeuroQuant® software. A negative AI value represented asymmetry towards the right due to reduced left hemispheric volume; a positive AI value represented asymmetry towards the left due to reduced right hemispheric volume. Subsequently, differences in volume and asymmetric patterns were investigated among TLE subgroups (right and left-sided TLE) and controls. Results: The left-sided TLE patients showed significant bilateral total brain volume reduction compared to the control group. Significant ipsilateral volumetric declines were also detected in the premotor cortex, the temporal lobe, and NAc with remarkable asymmetry to the right side. No significant changes were detected in right-sided TLE patients compared to the other groups. Conclusion: Overall, findings suggest that TLE patients had volumetric alterations with symmetry changes beyond the mesial temporal structures. With further investigations, the asymmetry measures can provide additional knowledge for TLE diagnosis. [ABSTRACT FROM AUTHOR]

This study aims to evaluate qualitative and quantitative imaging metrics along with clinical features affecting overall survival in glioblastomas and to classify them into high survival and low survival groups based on 12, 19, and 24 months thresholds using machine learning. The cohort consisted of 98 adult glioblastomas. A standard brain tumor magnetic resonance (MR) imaging protocol, was performed on a 3T MR scanner. Visually Accessible REMBRANDT Images (VASARI) features were assessed. A Kaplan-Meier survival analysis followed by a log-rank test and multivariate Cox regression analysis were used to investigate the effects of VASARI features along with the age, gender, the extent of resection, pre- and post-KPS, ki67 and P53 mutation status on overall survival. Supervised machine learning algorithms were employed to predict the survival of glioblastoma patients based on 12, 19, and 24 months thresholds. Tumor location (p <0.001), the proportion of non-enhancing component (p =0.0482), and proportion of necrosis (p =0.02) were significantly associated with overall survival based on Kaplan-Meier analysis. Multivariate Cox regression analysis revealed that increases in proportion of non-enhancing component (p =0.040) and proportion of necrosis (p =0.039) were significantly associated with overall survival. Machine-learning models were successful in differentiating patients living longer than 12 months with 96.40% accuracy (sensitivity=97.22%, specificity=95.55%). The classification accuracies based on 19 and 24 months survival thresholds were 70.87% (sensitivity=83.02%, specificity=60.11%) and 74.66% (sensitivity=67.58%, specificity=82.08%), respectively. Employing clinical and VASARI features together resulted in a successful classification of glioblastomas that would have a longer overall survival. • VASARI features were highly predictive of the overall survival of glioblastomas. • Machine learning resulted in high accuracies for identifying glioblastomas with overall survival of longer than 12 months. • Clinical and VASARI features of glioblastomas may help to identify high-risk patients. [ABSTRACT FROM AUTHOR]

Bisabolol is one of the bioactive constituents of chamomile. It was aimed to biotransform (-)-α-bisabolol by different fungi for the production of new bioactive metabolites, which was converted to α-bisabolol oxide A and B by Thamnidium elegans. Additionally, the biotransformation by Penicillium neocrassum yielded a new metabolite, which was characterized as 2-(5-methyl-5-(6-methyl-7-oxabicyclo[4.1.0]heptan-3-yl)tetrahydrofuran-2-yl)propan-2-ol = bisafuranol. The substrate and its metabolite mixtures were tested using antioxidant DPPH• scavenging assay. Antimicrobial activity was evaluated by an in vitro microdilution assay against a panel of human pathogenic bacteria and yeasts resulting in the lowest MIC and MFC values of 150 µg/mL. (-)-α-Bisabolol was effective against Propionibacterium acnes and Staphylococcus epidermidis (75, 37.5 µg/mL, respectively). The antioxidant activity of the metabolites was found to be more effective in scavenging free radicals. [ABSTRACT FROM AUTHOR]

Accurate digital representation of major white matter bundles in the brain is an important goal in neuroscience image computing since the representations can be used for surgical planning, intra-patient longitudinal analysis and inter-subject population connectivity studies. Reconstructing desired fiber bundles generally involves manual selection of regions of interest by an expert, which is subject to user bias and fatigue, hence an automation is desirable. To that end, we first present a novel anatomical representation based on Neighborhood Resolved Fiber Orientation Distributions (NRFOD) along the fibers. The resolved fiber orientations are obtained by generalized q-sampling imaging (GQI) and a subsequent diffusion decomposition method. A fiber-to-fiber distance measure between the proposed fiber representations is then used in a density-based clustering framework to select the clusters corresponding to the major pathways of interest. In addition, neuroanatomical priors are utilized to constrain the set of candidate fibers before density-based clustering. The proposed fiber clustering approach is exemplified on automation of the reconstruction of the major fiber pathways in the brainstem: corticospinal tract (CST); medial lemniscus (ML); middle cerebellar peduncle (MCP); inferior cerebellar peduncle (ICP); superior cerebellar peduncle (SCP). Experimental results on Human Connectome Project (HCP)’s publicly available “WU-Minn 500 Subjects + MEG2 dataset” and expert evaluations demonstrate the potential of the proposed fiber clustering method in brainstem white matter structure analysis. [ABSTRACT FROM AUTHOR]

Objective: The ultimate anatomy of the Meyer's loop continues to elude us. Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) may be able to demonstrate, in vivo, the anatomy of the complex network of white matter fibers surrounding the Meyer's loop and the optic radiations. This study aims at exploring the anatomy of the Meyer's loop by using DTI and fiber tractography. Methods: Ten healthy subjects underwent magnetic resonance imaging (MRI) with DTI at 3 T. Using a region-of-interest (ROI) based diffusion tensor imaging and fiber tracking software (Release 2.6, Achieva, Philips), sequential ROI were placed to reconstruct visual fibers and neighboring projection fibers involved in the formation of Meyer's loop. The 3-dimensional (3D) reconstructed fibers were visualized by superimposition on 3-planar MRI brain images to enhance their precise anatomical localization and relationship with other anatomical structures. Results: Several projection fiber including the optic radiation, occipitopontine/parietopontine fibers and posterior thalamic peduncle participated in the formation of Meyer's loop. Two patterns of angulation of the Meyer's loop were found. Conclusions: DTI with DTT provides a complimentary, in vivo, method to study the details of the anatomy of the Meyer's loop. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of the study was to investigate the role of Diffusion Tensor Imaging (DTI) and Diffusion Tensor Tractography (DTT) on the corticospinal tract alterations due to space occupying lesions in the brainstem before and after surgical resection. Pre- and post-surgical DTI data were acquired in 14 patients undergoing surgical resection of brainstem lesions. Patterns of corticospinal tract (CST) alteration on DTT were compared with the neurological exams of the patients pre- and post-operatively. DTT, especially in 3D movie format, seemed very helpful for evaluating the relationship of the lesions with the corticospinal tracts for surgical approach. None of the patients developed additional motor deficit related to surgery except one patient who presented with cerebellar ataxia after surgery. All of the patients with normal CST on DTT presented without motor deficit on neurological exam. The sensitivity, specificity, positive predictive and negative predictive values of DTT before surgery were 100%, 63.6%, 42.9% and 100%, and the corresponding values after surgery were 100%, 96%, 75% and 100% respectively. Although it has low specificity before surgery, DTT is a potentially useful technique in evaluating the effects of brainstem lesions and surgical resection on the relevant corticospinal tracts with high negative predictive value and higher specificity after surgery. [Copyright &y& Elsevier]

Introduction: Different influences of ovarian hormones in schizophrenia (SCZ) have been reported, but no study to date has assessed their effects on the brain dynamics at rest. The present study aimed to examine the hormonal and clinical changes related to the menstrual cycle and alterations in the resting-state functional connectivity (RS-FC) depending on cycle phase and/or hormonal fluctuations in SCZ. Method: This study was conducted based on both between- and within-subject experimental designs, including 13 clinically stable female patients with SCZ (32 ± 7.7 years) and 13 healthy women (30 ± 7.3 years). RS-functional magnetic resonance imaging (fMRI) scanning, as well as hormonal and clinical assessments, was applied to each participant twice during two cycle phases: early follicular and mid-luteal. Results: A difference in mid-luteal progesterone levels was found between groups, with a large effect size (Cohen's d) of 0.8 (p < 0.05). Also, the estradiol levels negatively correlated with the negative symptom severity of the patients during their mid-luteal phase. In the patients, estrogen positively correlated with the auditory network connectivity in the left amygdala during the early follicular phase. In the controls, progesterone had positive correlations with the connectivity of the posterior default mode and the left frontoparietal networks in the bilateral precuneus during the early follicular phase and had a negative correlation with the executive control network connectivity in the mid-luteal phase. Conclusion: The present study showed hormonal differences between groups and suggested that the levels of cycle-dependent hormones might be associated with the changes in clinical symptom severity and the RS-FC in the groups. Our RS-fMRI findings warrant further investigation. [ABSTRACT FROM AUTHOR]

Tractography refers to the in vivo reconstruction of fiber bundles, e.g., in brain, via the analysis of anisotropic diffusion patterns measured by diffusion weighted magnetic resonance imaging (DWI). The data provides a probabilistic model of local diffusion which was shown to correlate with the underlying fibrous structure under certain assumptions. Deterministic tractography suffers from uncertainties at kissing and crossing fibers, at different levels depending on the diffusion model employed (e.g., DTI, HARDI), yet it is easy to interpret and use in clinic. In this study, a novel generic algorithm, split and merge tractography (SMT), is proposed that provides a real-time, interactive and reliability ranked assessment of potential pathways, communicating the true information content of the data without sacrificing the usability of tractography. Specifically, SMT takes in a precomputed set of tracts and the diffusion data (e.g., DTI, HARDI) as its input, generates a set of short (reliable) tracts via splitting at unreliable points and forms quasi-random clusters of short tracts by means of which the space of short tract clusters, representing complete tracts, is sampled. A histogram of thus formed clusters is built in an efficient way and used for real-time, interactive assessment of pathways. The current implementation uses DTI and fourth-order Runge-Kutta integration based streamline tractography as its input. The method is qualitatively assessed on phantom DTI data and real DTI data. Phantom experiments demonstrated that SMT is capable of highlighting the problematic regions and suggesting pathways that are completely overseen by input streamline tractography. Real data experiment results correlate well with known anatomy and also demonstrate that the reliability ranking can efficiently suppress the erroneous tracts interactively. The method is compared to a recent method that also pursues a similar approach, yet in a global optimization based framework. The comparative study on real DTI data revealed the lower computational load of SMT and a better correlation with known anatomy. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: The purpose of this study was to determine the normative apparent diffusion coefficient (ADC) values at 3T using high b-value (3000s/mm2) diffusion-weighted images (DWI) and compare the signal characteristics of the high b value with standard b-value (1000s/mm2) DWI. Methods: Institutional review board approval was obtained for this prospective study which included 20 volunteers (10 M, 10 F, mean age: 38.7±14.9) without any known clinical disease or radiological findings. All brain examinations were performed with 3T MR by using similar parameters of b1000 and b3000 DWI sequences. DWI and ADC maps were obtained. Signal intensity, noise, signal to noise ratio (SNR), contrast to noise (CNR), contrast ratio (CR), and ADC values of bilateral posterior limb of internal capsule, frontal white matter, parietal gray matter, pons, thalamus, splenium of corpus callosum were measured on b1000 and b3000 DW images. Results: In all anatomic locations, MR signal intensity, SNR and ADC values of b3000 images were significantly lower than MR signal intensity, SNR and ADC values of b1000 images (p <0.001). The CNR and CR values at the posterior limb of internal capsule and pons were significantly increased on b3000 images (p <0.001) and decreased in the other regions measured. Conclusion: The ADC values calculated from standard b-value DWI were significantly higher than those calculated from high b-value DWI. These results agree with the previous studies. In the regions where CNR values increase with high b value, b3000 DWI images may provide additional clinical information. [Copyright &y& Elsevier]

Spontaneous intracranial hypotension (SIH) is an unusual syndrome that is characterised by positional headache, neck rigidity, nausea and vomiting. The characteristic magnetic resonance imaging (MRI) findings are diffuse smooth pachymeningeal thickening and enhancement, downward displacement of posterior fossa structures and pituitary gland enlargement. An unusual case of SIH with pituitary macro–adenoma and subsequent subdural haemorrhage is presented, and its clinical picture, MRI findings and possible pathophysiological mechanism are discussed. [ABSTRACT FROM AUTHOR]

Visual field defects (VFD) due to Meyer's loop injury may occur after temporal lobe resection surgery. Diffusion tensor tractography (DTT) of the Meyer's loop may reduce the risk of postoperative VFD. Currently, there is no standardized method to perform tractography for this structure. We performed DTT of the Meyer's loop in 10 healthy subjects and demonstrated the complex arrangement of the various projection fibers that compose the Meyer's loop and the complex relations with the neighbouring fiber systems. Evaluation of the Meyer's loop through the use of tractography may be a useful method to predict VFD after temporal resection surgery and this anatomical knowledge may be used to build surgical strategies and tactics to avoid the risk of intraoperative damage to this structure. [ABSTRACT FROM AUTHOR]

Visual field defects (VFD) due to Meyer's loop injury may occur after temporal lobe resection surgery. Diffusion tensor tractography (DTT) of the Meyer's loop may reduce the risk of postoperative VFD. Currently, there is no standardized method to perform tractography for this structure. We performed DTT of the Meyer's loop in 10 healthy subjects and demonstrated the complex arrangement of the various projection fibers that compose the Meyer's loop and the complex relations with the neighbouring fiber systems. Evaluation of the Meyer's loop through the use of tractography may be a useful method to predict VFD after temporal resection surgery and this anatomical knowledge may be used to build surgical strategies and tactics to avoid the risk of intraoperative damage to this structure. [ABSTRACT FROM AUTHOR]

Background Delusional disorder (DD) is a rare and understudied psychiatric disorder. There is limited number of studies concerning cognitive characteristics in DD. Using an established working memory paradigm with variable levels of memory load, we investigated alterations in functional magnetic resonance imaging (fMRI) of brain regions in patients with DD. Methods This case control study included 9 patients with DD and 9 healthy control subjects matched for age, sex, and education level. Diagnosis of DD was confirmed using the Structured Clinical Interview for DSM-IV Axis I. The severity of the symptoms was evaluated using the Positive and Negative Syndrome Scale. All patients were asked to perform 0-back and 2-back tasks during fMRI experiments. Functional imaging was performed using the 3.0 T Philips whole-body scanner using an 8-channel head coil. Results Participants with DD had less neural activation of the left dorsolateral prefrontal cortex in fMRI scans obtained during performance tasks. On the other hand, neural activation of the left and right superior temporal gyrus, left middle and inferior temporal gyrus, right and left posterior cingulate gyrus, right amygdala, left and right fusiform gyrus was more prominent in patients with DD in comparison with the control group. Discussion Patients with DD had dysfunction in the prefrontal, temporal and limbic regions of the brain in particular, during performance tasks of working memory. Our findings were in line with the findings of the early reports on deficient functioning in temporal or limbic regions of the brain. Further, patients with DD displayed prefrontal dysfunction as seen in patients with schizophrenia. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: The utility of DWI with high b-value in ischemic stroke is still unsettled. The purpose of this study is to compare high b-value (3000) and standard b-value (1000) diffusion-weighted images in patients with ischemic stroke at 3T. Materials and methods: 27 patients with acute stroke who were admitted to the hospital during the first 24h after symptom onset were included in this study. All patients had a brain MRI study with stroke protocol including standard (b =1000) DWI and high b-value (b =3000) DWI sequences at 3T MR scanner. Number and localization of the lesions were assessed MR signal intensities (SI), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), contrast ratio (CR) and apparent diffusion coefficient (ADC) values of the lesions and normal parenchyma on DWI with b =1000 and b =3000 sequences were measured. Results: All patients with acute stroke revealed hyperintense lesions due to restricted diffusion on DWI with both b-values. However, lesions of restricted diffusion were more conspicuous in b =3000 value DWI than b =1000, and additional 4 ischemic lesions were detected on b =3000 DWI. SNR, CNR, SI and also ADC values in both stroke area and normal parenchyma were lower at b =3000 than the value at b =1000. At b =3000, CR was significantly greater than b =1000 images. Conclusions: Although quantitative analysis shows higher SI, SNR and CNR values with standard b-value (b =1000) diffusion-weighted imaging, using higher b-value may still be beneficial in detecting additional subtle lesions in patients whose clinical findings are not correlated with standard b-value DWI in stroke. [Copyright &y& Elsevier]

The aim of this study was to assess the feasibility of diffusion tensor imaging (DTI) of the prostate and to determine normative fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of healthy prostate with a 3-Tesla magnetic resonance imaging (MRI) system. Thirty volunteers with a mean age of 28 (25-35) years were scanned with a 3-Tesla MRI (Intera Achieva; Philips, The Netherlands) system using a six-channel phased array coil. Initially, T2-weighted turbo spin-echo (TSE) axial images of the prostate were obtained. In two subjects, a millimetric hypointense signal change was detected in the peripheral zones on T2-weighted TSE images. These two subjects were excluded from the study. DTI with single-shot echo-planar imaging (ssEPI) was performed in the remaining 28 subjects. ADC and FA values were measured using the manufacturer supplied software by positioning 9-pixel ROIs on each zone. Differences between parameters of the central and peripheral zones were assessed. Mean ADC value of the central (1.220 +/- 0.271 x 10(-3) mm(2)/s) was found to be significantly lower when compared with the peripheral gland (1.610 +/- 0.347 x 10(-3) mm(2)/s) (P < 0.01). Mean FA of the central gland was significantly higher (0.26), compared with the peripheral gland (0.16) (P < 0.01). This study shows the feasibility of prostate DTI with a 3-Tesla MR system and the normative FA and ADC values of peripheral and central zones of the normal prostate. The results are compatible with the microstructural organization of the gland. [ABSTRACT FROM AUTHOR]

BACKGROUND AND AIM: The presence of hepatocellular carcinoma (HCC) has important implications for patients with cirrhosis. Studies have not compared the risk of cancer in cirrhotic patients with small liver nodules to cirrhotic patients without nodules. Our aim was to determine the risk of HCC in cirrhotic patients with small liver nodules on MRI compared to those without nodules. METHODS: We conducted a prospective study to determine the rate of HCC in cirrhotic patients with and without liver nodules. Cases were patients with liver nodule(s) less than 2 cm on MRI and controls were cirrhotic patients without nodules. Kaplan-Meier estimates and multivariate analysis were performed to estimate the risk of HCC in the two groups. RESULTS: A total of 310 liver transplant candidates with a mean follow-up of 663 days were included in the study and 133 underwent liver transplant during follow-up. The 1-yr incidence of HCC in the liver nodule group and control group was 11% and 0.5%, respectively, p < 0.001. The adjusted risk for HCC in the liver nodule group was 25 times higher compared to the control group, HR = 25.1 [95% CI 8.0, 78.9]. In 133 candidates who underwent transplant with and without liver nodules the rate of HCC was 11 (50%) and 4 (3.6%), respectively, p < 0.001. CONCLUSION: The incidence of HCC in patients with small liver nodules is significantly higher compared to patients with cirrhosis without liver nodules. The presence of small liver nodules warrants increased imaging surveillance for HCC. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To assess by MR imaging the frequency of hepatic nodules in patients waiting on the liver transplant list and to determine whether certain underlying hepatic diseases were more often associated with the development of such hepatic nodules. Material and Methods: We reviewed the MR and clinical records in all patients seen by the liver transplant service at our center since its inception in January 1998 until September 2002. A total of 371 patients (207 men and 164 women, age range 18–68 years, mean 45 years) were included in the study. The presence of hepatic nodules, size, number and underlying hepatic diseases were determined in all patients. Magnetic resonance imaging was performed on a 1.5-T MR imager using T1-weighted, T2-weighted and multi-phase gadolinium-enhanced sequences. Odds ratio (OR) and 95% confidence intervals (CIs) were computed to evaluate the association between the underlying hepatic disease and the development of hepatic nodule. Results: Among 371 liver transplantation candidates, the most common underlying hepatic disease was hepatitis C virus (HCV) infection, either alone (n=93; 25%) or associated with other hepatic diseases (n=40; 10.8%). Of all patients, 33 (8.9%) had regenerative nodules (RNs), 40 (10.7%) dysplastic nodules (DNs) and 57 (15.3%) hepatocellular carcinomas (HCCs). Hepatocellular carcinoma was observed in 35.3% of patients with HCV infection and alcohol abuse combined, 24.5% with cryptogenic cirrhosis, 25% with hemochromatosis and 19% with alcohol abuse. Patients who had either DNs or HCC were 2.5 times more likely to have either alcohol abuse or HCV, alone or combined, as the substrate of their liver disease (OR 2.54, 95% CI 1.56–4.13). Our data suggest a supra-additive interaction between HCV infection and ethanol in their association with MR imaging detected lesions. Conclusion: Patients with cryptogenic cirrhosis, alcohol abuse, HCV infection (alone or combined) and hemochromatosis had the greatest likelihood of having HCC, with the combination of HCV infection and alcohol abuse having the highest of all. [Copyright &y& Elsevier]

Abstract: We describe the MR appearance of breast cancer metastases to the stomach. The stomach wall was diffusely thickened with loss of the regular fold pattern best shown on the single shot T2-weighted images and enhanced with moderate mural enhancement on early and late post gadolinium images. The combination of gastric wall thickening and abnormal enhancement should suggest the diagnosis of diffuse mural metastases in a woman with a history of breast cancer. [Copyright &y& Elsevier]

We report the magnetic resonance (MR) appearance of a large B-cell lymphoma in the peripancreatic head region, in a 38-year-old male who presented with a 1-month history of pruritus and jaundice. Routine laboratory examination at presentation revealed an elevated bilirubin. The tumor was a large, solitary well-defined mass with no evidence of necrosis, which showed mild diffuse heterogeneous enhancement. The tumor was closely applied to the lateral margin of the head of the pancreas. The constellation of MR findings was interpreted as consistent with the correct eventual diagnosis of lymphoma. [Copyright &y& Elsevier]

We report the MR appearance of undifferentiated (embryonal) sarcoma of the liver (USL) in a 13-year-old female who presented with a 1-year history of intermittent abdominal pain, weight loss, and fatigue. The tumor was a large, solitary, well-defined focal mass lesion with multiple cystic spaces, septations, and substantial central necrosis. [Copyright &y& Elsevier]

Abstract: We report the MRI findings of primary small-cell carcinoma of the kidney (PSCCK) in a 59-year-old female. This tumor appeared as a 16-cm mass that arose from the right kidney. This lesion had diminished signal on T1-weighted images and heterogeneous mixed signal on T2-weighted images. The tumor primarily involved the renal medulla with persistent thin renal cortex. Despite the tumors'' large size, no substantial central necrosis was present. The predominant medullary location and the lack of central necrosis in this large tumor were features unusual for renal cell carcinoma and should raise the suspicion of another malignancy, the differential diagnosis of which should contain extrapulmonary small-cell carcinoma of the kidney. [Copyright &y& Elsevier]

A correction to the article on the surname of the 6th author was misspelled.