The Value of Magnetic Resonance Diffusion-Weighted Imaging and Dynamic Contrast Enhancement in the Diagnosis and Prognosis of Treatment Response in Patients with Epithelial Serous Ovarian Cancer.

Background. The aim of our study was to describe the selected parameters of diffusion-weighted imaging (DWI) and perfusion dynamic contrast enhancement (DCE) MRI in primary tumors in patients with serous epithelial ovarian cancer (EOC), as well as in disease course prognosis and treatment response, including bevacizumab maintenance therapy. Materials and Methods. In total, 55 patients with primary serous EOC were enrolled in the study. All patients underwent MR imaging using a 1.5 T clinical whole-body MR system in preoperative DWI and DCE MRI selected parameters: apparent diffusion coefficients (ADC), time to peek (TTP) and perfusion maximum enhancement (Perf. Max. En.) were measured. The data were compared with histopathological and immunochemistry results (with Ki67 and VEGF expression) and clinical outcomes. Results. Higher mean ADC values were found in low-grade EOC compared to high-grade EOC: 1151.27 vs. 894,918 (p < 0.0001). A negative correlation was found between ADC and Ki67 expression (p = 0.027), and between ADC and VEGF expression (p = 0.042). There was a negative correlation between TTP and PFS (p = 0.0019) and Perf. Max. En. and PSF (p = 0.003). In the Kaplan−Meier analysis (log rank), a longer PFS was found in patients with ADC values greater than the median; p = 0.046. The Kaplan−Meier analysis showed a longer PFS (p = 0.0126) in a group with TTP below the mean value for this parameter in patients who received maintenance treatment with bevacizumab. Conclusions. The described relationships between PFS and DCE and DWI allow us to hope to include these parameters in the group of EOC prognostic factors. This aspect seems to be of particular interest in the case of the association of PFS with DCE values in the group of patients treated with bevacizumab.

New insights into NAFLD based on preclinical MRI studies.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is considered to be the leading cause of liver pathologies worldwide. Accurate diagnosis and staging of NAFLD is of utmost prognostic importance. Herein, we propose the application of multiparametric MRI in whole-body fat imaging that may serve in obesity and NAFLD diagnosis as we established based on an experimental preclinical model of high-calorie diet-induced NAFLD rats. METHODS AND RESULTS: Sprague Dawley male rats randomly divided into control and high-fat diet (HFD) groups to develop NAFLD were used in the experiments. After 12 weeks of the feeding the animals were subjected to MRI modalities based on the Dixon mode and DWI following T2-weighted imaging. Moreover, serum TAG, liver histopathological examination and liver fatty acids analysis (GC-MS) were also performed. The qualitative analysis of DWI images revelated the decrease of signals in the liver of rats subjected to HFD. The statistical analysis of signals from the water- and fat-separated voxels on Dixon images also showed the increase of the fat tissue along with the decrease of water molecules in the liver parenchyma of obese animals. The quantitative analysis of Dixon images allowed to estimate the statistically significant changes of whole-body fat profiles in both normal and obese rats. Histological analysis of the liver tissues, serum TAG and fatty acids profile in the livers confirmed the changes in the fat profile as demonstrated in MRI studies. CONCLUSIONS: The MRI-based modalities such as DWI and Dixon method provide both qualitative and quantitative data on the whole-body fat distribution and adipose tissues in the liver parenchyma of obese rats. The results show that MRI is a promising and reliable method and has potential to be used as a non-invasive translational biomarker in NAFLD.

Radiographic Measurement of Gastric Remnant Volume After Laparoscopic Sleeve Gastrectomy: Assessment of Reproducibility and Correlation with Weight Loss.

BACKGROUND: As a restrictive procedure, laparoscopic sleeve gastrectomy (LSG) relies primarily on the reduction of gastric volume. It has been suggested that an immediate postoperative gastric remnant volume (GRV) may influence long-term results of LSG; however, there are no consensus in this matter. The aim of this study was to assess the reproducibility of different radiographic methods of GRV calculation and evaluate their correlation with the weight loss (WL) after surgery. METHODS: This retrospective study evaluated 174 patients who underwent LSG in the period from 2014 to 2017. Using UGI, GRV was measured with 3 different mathematical methods by 2 radiologists. Intraobserver and interobserver calculations were made. Correlation between GRV and WL were estimated with calculations percentage of total weight loss (%TWL) and percentage of excess weight loss (%EWL) after 1, 3, 6, 12, 18, and 24 months postoperatively. RESULTS: During analysis of intraobserver similarities, the results of ICC calculation showed that reproducibility was good to excellent for all GRV calculation methods. The intraobserver reproducibility for Reader I was highest for cylinder and truncated cone formula and for Reader II for ellipsoid formula. The interobserver reproducibility was highest for ellipsoid formula. Regarding correlation between GRV and WL, significant negative correlation has been shown on the 12th month after LSG in %TWL and %EWL for every method of GRV calculation, most important for ellipsoid formula (%TWL - r(X,Y) = -0.335, p < 0.001 and %EWL - r(X,Y) = -0.373, p < 0.001). CONCLUSION: Radiographic methods of GRV calculation are characterized by good reproducibility and correlate with the postoperative WL.

Brain activity underlying response induced by SNARC­congruent and SNARC­incongruent stimuli.

At least three well-documented phenomena indicate a relationship between numbers and the internal representation of space. They are shifting attention in accordance with the localization of numbers on the mental number line (MNL); the spatial­numerical association of response codes (SNARC) effect, which manifests as faster responses to high numbers with the right hand than with the left, and vice versa for low numbers; and the processing of both numbers and space primarily in the parietal cortex. Some EEG studies have pointed to the response selection stage as a locus of this effect. However, this explanation has yet to be corroborated by the fMRI experiments. The goal of this study was to investigate the functional anatomy underlying response selection induced by SNARC­congruent and SNARC­incongruent stimuli in a spatial visual cueing task. Healthy adult volunteers responded to a pair of target stimuli consisting of digits, non­digit symbols, or a mix of both. In each trial, the stimuli were preceded by a centrally presented numerical or non­numerical cue stimulus which was required to be memorized. One of the target stimuli that then appeared would be identical to the cue; the task was to determine which side it was presented on, within the pair. In the case of numerical stimuli, the side was congruent with its localization on the MNL in one­half of the trials. In the other half of the trials, it was incongruent. The behavioral results revealed the SNARC effect, as well as a faster reaction to low numbers than to high numbers. The fMRI responses to the target stimuli showed engagement of regions implicated in number processing but also in sensory­motor areas. This suggests that the motor response selection or execution stage may be the locus of the SNARC effect. Yet, the activation pattern obtained in the congruent and incongruent conditions did not allow us to determine, indisputably, the neural correlates of the mechanisms involved in the SNARC effect. Moreover, we did not observe any stimulus-specific responses to cues.

Diffusion Weighted Magnetic Resonance Imaging in the Assessment of Renal Function and Parenchymal Changes in Chronic Kidney Disease: A Preliminary Study.

BACKGROUND The aim of this study was to evaluate the feasibility of using intravoxel incoherent motion (IVIM) imaging for noninvasive assessment of pathologic changes in chronic kidney disease (CKD). MATERIAL AND METHODS Thirty-four patients with CKD and 20 healthy volunteers were examined on a 1.5 T magnetic resonance imaging (MRI) unit. The examination consisted of morphologic sequences and diffusion-weighted echo-planar sequence with 10 b values. Diffusion parameters were calculated with the use of mono- (apparent diffusion coefficient, ADC) and bi-exponential model: pure diffusion coefficient (D) and perfusion fraction (Fp). Blood samples to assess the serum creatinine level were taken immediately before examination. Ultrasound guided biopsies were performed in less than 30 days from MRI and were scored by an experienced nephropathologist. Parametrical unpaired t-test and ROC curve analysis were used to investigate differences in diffusion parameters in relation to estimated glomerular filtration rate (eGFR). Pearson's correlation coefficients were calculated to assess relationship between diffusion parameters and laboratory and histopathological markers of renal damage. P-value <0.05 indicated statistical significance. RESULTS Both ADC and D correlated positively with eGFR (respective r 0.74 and 0.72), however D showed a more significant correlation with histopathology: while D correlated negatively with parameters reflecting chronic glomerular (r -0.48) and tubulo-interstitial changes (r -0.47), ADC correlated only with interstitial infiltrations (r -0.44). Flow-related diffusion parameters showed high standard deviation. CONCLUSIONS IVIM imaging is sensitive to functional and morphologic changes in CKD. The separation of influence of Fp from true diffusion improves the assessment of chronic changes in renal parenchyma.

Role of Diffusion Tensor Imaging Parameters in the Characterization and Differentiation of Infiltrating and Non-Infiltrating Spinal Cord Tumors : Preliminary Study.

BACKGROUND AND PURPOSE: Recent attempts to utilize diffusion tensor imaging (DTI) to identify the extent of microinfiltration of a tumor in the brain have been successful. It was therefore speculated that this technique could also be useful in the spinal cord. The aim of this study was to differentiate between infiltrating and noninfiltrating intramedullary spinal tumors using DTI-derived metrics. MATERIAL AND METHODS: The study group consisted of 6 patients with infiltrating and 12 with noninfiltrating spinal cord tumors. Conventional magnetic resonance imaging (MRI) with gadolinium administration was performed followed by DTI. Fractional anisotropy (FA), diffusivity (TRACE) and apparent diffusion coefficient (ADC) were measured in the enhancing tumor mass, peritumoral margins, peritumoral edema and normal appearing spinal cord. The results were compared using non-parametric Mann-Whitney U test with statistical significance p < 0.05. RESULTS: In peritumoral margins the FA values were significantly higher in the noninfiltrating compared to the infiltrating tumors (p < 0.007), whereas TRACE values were significantly lower (p < 0.017). The results were similar in peritumoral edema. The FA values in the tumor mass showed no significant differences between the two groups while TRACE showed a statistically significant difference (p < 0.003). There was no statistical difference in any parameters in normal appearing spinal cord. CONCLUSION: Quantitative analysis of DTI parameters of spinal cord tissue surroundings spinal masses can be useful for differentiation between infiltrating and non-infiltrating intramedullary spinal tumors.

MRI-based preclinical discovery of DILI: A lesson from paracetamol-induced hepatotoxicity.

Worldwide, drug-induced liver injury (DILI) is a major cause of hepatic failure. It is also the leading cause of withdrawal, cautionary labeling, and restricted usage of licensed drugs; therefore, European Medicines Agency (EMA) and United States Food and Drug Administration (FDA) warn that the existing methods of assessing DILI are insufficient and that some of the translational biomarkers of hepatotoxicity must be relooked. Magnetic resonance imaging (MRI) seems to be a proper tool in elucidating the effects of DILI in both preclinical and clinical studies, providing excellent visualization of the morphology of the liver parenchyma. Therefore, herein, we propose preclinical MRI assessment of liver injury in experimental paracetamol-treated rats. Quantitative MRI clearly provides evidence of adverse effects in the liver tissue caused by a single overdose of paracetamol (1 g kg-1 and 1.5 g kg-1 b.w.). The results of the MRI were confirmed by the histopathological examination (H&E) of the rat liver specimen, however the adverse effects were not disclosed due to standard aminotransferase assays (ALT/AST) in rat blood serum. The results of our analysis demonstrate the successful application of MRI in the examination of paracetamol-induced hepatotoxicity in rats; it has a potential to serve as the early diagnostic tool for the prediction of DILI in preclinical evaluation.

Magnetic resonance diffusion-weighted imaging in diagnostics of primary fallopian tube carcinoma - is it useful?

PURPOSE: Primary fallopian tube carcinoma (PFTC) is the rarest form of female genital malignancy. The imaging applied for suspected adnexal masses includes transvaginal ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI), but the vast majority of PFTC is recognised intraoperatively. MATERIAL AND METHODS: The study group consisted of seven women with postoperatively histopathological diagnosis of PFTC. To recognise characteristic findings for PFTC, retrospective analysis of preoperative MRI was performed. All patients underwent MRI of the pelvis and abdomen using a 1.5T MR system. Based on the results of the above imaging, suspected adnexal masses were recognised. MRI protocol contained T2-weighted images, fat-suppressed T2-weighted, T2-TIRM, DW EPI, pre- and postcontrast dynamic 3D T1 GRE in transverse orientation, with diffusion weightings of 0, 50, 100, 150, 200, 400, 800, and 1200 s/mm2. Regions of interest were outlined by a radiologist, who documented the character of adnexal masses on diffusion-weighted (DW) images and apparent diffusion coefficient (ADC) maps. RESULTS: In all seven patients with PFTC unilateral tumour was found. On all DW images (with ß values of 0, 50, 100, 150, 200, 400, 800, and 1200 s/mm2) the mean signal intensities of solid parts of tumour were significantly higher than the mean signal intensities of normal ovarian tissue (p = 0.0001). There were no statistically significant differences between eight ß values applied for ADC calculations. CONCLUSIONS: Preoperative diagnostics of PFTC is difficult and mainly based on morphological features. Previous research did not show characteristics of PFTC in post-contrast dynamic imaging. In our material a clear increasing of signal intensity in DW imaging occurred independently of the ß value.

Gd-EOB-DTPA-Enhanced MR Imaging of the Liver: The Effect on T2 Relaxation Times and Apparent Diffusion Coefficient (ADC).

BACKGROUND: To investigate the effect of gadoxetic acid disodium (Gd-EOB-DTPA) on T2 relaxation times and apparent diffusion coefficient (ADC) values of the liver and focal liver lesions on a 1.5-T system. MATERIAL/METHODS: Magnetic resonance (MR) studies of 50 patients with 35 liver lesions were retrospectively analyzed. All examinations were performed at 1.5T and included T2-weighted turbo spin-echo (TSE) and diffusion-weighted (DW) images acquired before and after intravenous administration of Gd-EOB-DTPA. To assess the effect of this hepatobiliary contrast agent on T2-weighted TSE images and DW images T2 relaxation times and ADC values of the liver and FLLs were calculated and compared pre- and post-injection. RESULTS: The mean T2 relaxation times of the liver and focal hepatic lesions were lower on enhanced than on unenhanced T2-weighted TSE images (decrease of 2.7% and 3.6% respectively), although these differences were not statistically significant. The mean ADC values of the liver showed statistically significant decrease (of 4.6%) on contrast-enhanced DW images, compared to unenhanced images (P>0.05). The mean ADC value of liver lesions was lower on enhanced than on unenhanced DW images, but this difference (of 2.9%) did not reach statistical significance. CONCLUSIONS: The mean T2 relaxation times of the liver and focal liver lesions as well as the mean ADC values of liver lesions were not significantly different before and after administration of Gd-EOB-DTPA. Therefore, acquisition of T2-weighted and DW images between the dynamic contrast-enhanced examination and hepatobiliary phase is feasible and time-saving.

Diffusion-Weighted Imaging of Small Peritoneal Implants in "Potentially" Early-Stage Ovarian Cancer.

INTRODUCTION: MRI is established modality for the diagnosis of ovarian malignancies. Advances in MRI technology, including DW imaging, could lead to the further increase in the sensitivity of MRI for the detection of peritoneal metastases. The aim of this study was to assess the accuracy of DW imaging for detection of peritoneal metastatic disease in patients suspected of having potentially early ovarian cancer and secondly to evaluate ADC values of peritoneal implants. MATERIALS AND METHODS: The prospective study group consisted of 26 women with sonographic or/and CT diagnosis of suspected ovarian tumor. Based on the results of the above imaging, in none of them was extraovarian spread of disease or ascites recognized. All patients underwent MRI with DW imaging. RESULTS: Overall, 18 extraovarian peritoneal lesions were found on DW images in 10 from 26 examined patients. All implants had diameter ≤10 mm. The presence of all lesions diagnosed by MRI was confirmed intraoperatively. Histopathologic findings in 17 proofs confirmed ovarian cancer. PPV was 94%. On all DW images (with b values of 0, 50, 100, 150, 200, 400, 800, and 1200 s/mm(2)) the mean signal intensities of peritoneal lesions were significantly higher than the mean signal intensities of normal adjacent tissue (p = 0.000001).

Sex, lies and fMRI--gender differences in neural basis of deception.

Deception has always been a part of human communication as it helps to promote self-presentation. Although both men and women are equally prone to try to manage their appearance, their strategies, motivation and eagerness may be different. Here, we asked if lying could be influenced by gender on both the behavioral and neural levels. To test whether the hypothesized gender differences in brain activity related to deceptive responses were caused by differential socialization in men and women, we administered the Gender Identity Inventory probing the participants' subjective social sex role. In an fMRI session, participants were instructed either to lie or to tell the truth while answering a questionnaire focusing on general and personal information. Only for personal information, we found differences in neural responses during instructed deception in men and women. The women vs. men direct contrast revealed no significant differences in areas of activation, but men showed higher BOLD signal compared to women in the left middle frontal gyrus (MFG). Moreover, this effect remained unchanged when self-reported psychological gender was controlled for. Thus, our study showed that gender differences in the neural processes engaged during falsifying personal information might be independent from socialization.

Characterization of focal liver lesions using quantitative techniques: comparison of apparent diffusion coefficient values and T2 relaxation times.

OBJECTIVES: To compare the efficacy of two quantitative methods for discrimination between benign and malignant focal liver lesions (FLLs): apparent diffusion coefficient (ADC) values and T2 relaxation times. METHODS: Seventy-three patients with 215 confirmed FLLs (115 benign, 100 malignant) underwent 1.5-T MRI with respiratory-triggered single-shot SE DWI (b = 50, 400, 800) and dual-echo T2TSE (TR = 3,000 ms; TE1 = 84 ms; TE2 = 228 ms). ADC values and T2 relaxation times of FLLs were calculated. Sensitivity, specificity and accuracy of both techniques in diagnosing malignancy were assessed. RESULTS: The mean ADC value of malignant tumours (1.07 × 10(-3) mm(2)/s) was significantly lower (P < 0.05) than that of benign lesions (1.86 × 10(-3) mm(2)/s ); however, with the use of the optimal cut-off value of 1.25 × 10(-3) mm(2)/s, 20 false positive (FP) and 20 false negative (FN) diagnoses of malignancy were noted, generating 79 % sensitivity, 82.6 % specificity and 80.9 % accuracy. The mean T2 relaxation time of malignant tumours (64.4 ms) was significantly lower (P < 0.05) than that of benign lesions (476.1 ms). At the threshold of 107 ms 22 FP and 1 FN diagnoses were noted; the sensitivity was 99 %, specificity 80.9 % and accuracy 89.3 %. CONCLUSIONS: Quantitative analysis of T2 relaxation times yielded significantly higher sensitivity and accuracy in diagnosing malignant liver tumour than ADC values. KEY POINTS: • Diffusion-weighted magnetic resonance imaging is increasingly used for liver lesions. • But ADC values demonstrated only moderate accuracy for differentiation of liver lesions. • T2 relaxation times yielded higher accuracy in diagnosing malignant liver tumours. • Both ADC and T2 values overlapped between focal nodular hyperplasia and malignant lesions. • Nevertheless T2 liver mapping could be valuable for evaluating focal liver lesions.

Sex hormone patterns in women with multiple sclerosis as related to disease activity--a pilot study.

BACKGROUND AND PURPOSE: The influence of sex hormones on immune system activity in multiple sclerosis (MS) has been suggested by clinical evidence. The aim of the study was to ana-lyse the pattern of sex hormones in MS women and to correlate the hormone pattern abnormalities to the disease course as well as to the magnetic resonance imaging (MRI) results. MATERIAL AND METHODS: We studied the serum level of the progesterone, ß-oestradiol and prolactin in 46 women with clinical definite MS aged from 19 to 65; mean disease duration was 11.80 ± 9.86 years. The evaluation of the intensity of hormonal changes was done using a scoring system (0-3). On the brain MRI, the presence of brain atrophy, of hypothalamic demyelination as well as demyelination intensity (or degree) were analysed. The evaluation of the degree of demyelination and brain atrophy was done using a scoring system (0-4). RESULTS: The main hormonal abnormalities consisted of decreased progesterone level, increased oestradiol level or both. The sex hormone pattern was abnormal in 56% of patients. Hypothalamic lesions were found on MRI in 53% of cases. The abnormal hormonal pattern correlated with intensity of MR changes (p < 0.05, Fisher's exact test), but neither with presence of hypothalamic changes nor with disease parameters (Expanded Disability Status Scale, relapse rate, disease duration). CONCLUSIONS: It is important to check the hormonal pattern in MS women because according to our results it may be related to the disease activity and probably affects the type of therapeutic intervention. This pilot study will be extended in a larger population.

Brain proton magnetic spectroscopy in long-term treatment of Wilson's disease patients.

We reported the brain proton magnetic resonance spectroscopy (MRS) findings in 27 Wilson's disease (WD) patients treated more than 6 years in neurological (nWD) and hepatic (hWD) subgroups. We investigated four hWD patients, with no improvement and eight with marked improvement; and eight nWD patients with marked improvement and seven with no improvement of clinical status. In nWD patients with improvement the MRS showed significantly higher Cho/Cr, Glx/Cr ratios levels. In hWD patients with no improvement the lower Cho/Cr and in nWD significantly lower NAA/Cr and higher Cho/Cr and Lip/Cr ratios were detected. In nWD patients with improvement the spectroscopic pattern, can be related to gliosis. In patients with no neurological improvement a persistent neuronal dysfunction can occur, perhaps as a result of copper or iron deposition.

Heterozygous carriers for Wilson's disease--magnetic spectroscopy changes in the brain.

Wilson's disease (WD) is an autosomal recessive disorder and the WD heterozygote carriers (Hzc) should not exhibit symptoms of the disease. The aim of this study was to assess 12 WD Hzc by brain Proton MR Spectroscopy. In three cases, the levels of caeruloplasmin, and in one case, serum copper, were below our normal range. In two Hzc the aspartate and alanine aminotransferase levels in the blood were slightly increased, however, no ultrasonographic liver changes were detected. The brain metabolite analysis showed a statistically significant higher mean ratio of Glx/Cr and Lip/Cr in MRS in Hzc in both the pallidum and thalami compared to control subjects. Our results suggest that WD Hzc may accumulate free copper in the basal ganglia.

Spectral changes in postoperative MRS in high-grade gliomas and their effect on patient prognosis.

The aim of the study was to find differences in magnetic resonance spectroscopy (MRS) which might facilitate differential diagnosis between tumour regrowth and a remnant tumour with present postradiation changes or postradiation necrosis in the vicinity of the postoperative bed, based on the assessment of the dynamics between two MRS, i.e. preoperative and postoperative scanning, performed at 6 months after surgery. Therefore, in 9 patients with high-grade gliomas, MRS spectra were obtained. Subsequently, a partial tumour resection was done in 5 patients, and 4 subjects underwent a gross total resection. On the second MRS the voxel was placed on an observed contrast enhancement area. The tumour regrowth onset was established by comparing the results of control MRI with postoperative CT scans, and also on the basis of changes in clinical condition as well as a further follow-up, including MRI studies. In patients with tumour regrowth Cho/NAA and Lac/Cr ratios increased and the NAA/Cr ratio decreased between the two MRS studies; in the patients without regrowth, the ratio changes were inverse. In both groups, a decrease in Cho/Cr ratio was observed. In a univariate analysis the presence of tumour regrowth and an increase in Cho/NAA ratio between the two MRS were correlated with a shorter further survival time; a tendency to shorter further survival time was noted with decrease in NAA/Cr ratio. In conclusion, MRS is a diagnostic tool which, on the basis of direction of changes in the value of metabolite ratios, helps additionally confirm the diagnosis of glioma regrowth. In the case of a visible contrast enhancement area on the postoperative MRI with observed concomitant increase in Cho/NAA ratio and decrease in NAA/Cr ratio between pre- and postoperative MRS examinations, preliminary suspicion should be that of glioma regrowth rather than of remnant tumour after surgery or postradiation lesions.

The effect of motivation on working memory: an fMRI and SEM study.

This study investigated the effective connectivity between prefrontal regions of human brain supporting motivational influence on working memory. Functional magnetic resonance imaging (fMRI) and structural equation modeling (SEM) were used to examine the interaction between the lateral orbitofrontal (OFC), medial OFC, and dorsolateral prefrontal (DLPFC) regions in the left and right hemisphere during performance of the verbal 2-back working memory task under two reinforcement conditions. The "low-motivation" condition was not associated with monetary reinforcement, while the "high-motivation" condition involved the probability of winning a certain amount of money. In the "low-motivation" condition, the OFC regions in both hemispheres positively influenced the left DLPFC activity. In the "high-motivation" condition, the connectivity in the network including the right OFC regions and left DLPFC changed from positive to negative, whereas the positive connectivity in the network composed of the left OFC and left DLPFC became slightly enhanced compared with the "low-motivation" condition. However, only the connection between the right lateral OFC and left DLPFC showed a significant condition-dependent change in the strength of influence conveyed through the pathway. This change appears to be the functional correlate of motivational influence on verbal working memory.

MR spectroscopy in monitoring the treatment of Wilson's disease patients.

The aim of this study was to determine the effectiveness of brain proton magnetic resonance spectroscopy ((1)H-MRS) for monitoring therapy in Wilson's disease (WD) patients. Voxels were located in the globus pallidus (right, left). We followed 17 newly diagnosed WD cases for 1-year period. During this observation period, 6 neurological and 9 hepatic patients improved, while 2 neurological patients deteriorated. The pretreatment (1)H-MRS analysis showed a statistically significant lower level of mI/Cr, NAA/Cr, and higher Lip/Cr in all WD patients with improvement compared with controls. In patients with hepatic signs, a statistically significant increase of mI/Cr and Glx/Cr was observed in the second (1 year posttreatment) (1)H-MRS. In patients with neurological improvement after treatment in the follow-up (1)H-MRS, a statistically significant increase of NAA/Cr was noted. During neurological deterioration, a decrease of Glx/Cr and NAA/Cr was seen, in contrast to another neurologically impaired patient with liver failure exacerbation, where a decrease of mI/Cr and increase of Glx/Cr was observed. The alternations of NAA/Cr ratio in neurologically impaired patients and mI/Cr and Glx/Cr in patients with liver failure could be a sensitive marker of the clinical recovery and deterioration in those WD patients. (1)H-MRS is a technique that can be used for accurate monitoring of treatment efficacy in WD patients.

Discrimination of benign from malignant hepatic lesions based on their T2-relaxation times calculated from moderately T2-weighted turbo SE sequence.

The differentiation of hemangioma from other hepatic neoplasms using MRI usually relies on the evaluation of heavily T2-weighted images. The aim of this study was to assess the value of T2-relaxation times calculated from moderately T2-weighted turbo spin-echo (TSE) sequence in characterization of focal hepatic lesions, including hepatic malignancies, focal nodular hyperplasia (FNH), hemangioma, and cyst. Fifty-two patients with 114 proven lesions (61 malignant masses, 6 focal nodular hyperplasias, 28 hemangiomas, 19 cystic lesions) were examined on 1.5-T system using a double-echo TSE sequence (TR=1800 ms; TE(eff) 1=40 ms; TE(eff) 2=120 ms). Signal intensities (SI) of the liver as well as SI of all lesions were measured, and then the T2-relaxation times were calculated. The mean T2 time for the liver was 54 ms (+/-8 ms), for FNH 66 ms (+/-7 ms), for malignant hepatic lesions 85 ms (+/-17 ms), for hemangiomas 155 ms (+/-35 ms), and for cystic lesions 583 ms (+/-369) ms. Most malignant hepatic lesions were best differentiated between the thresholds of 67 and 116 ms, generating a sensitivity of 90% and a specificity of 94%. There were six false-negative diagnoses of malignant tumor and three false-positive cases (two hemangiomas and one FNH). Calculation of the T2-relaxation times obtained from the double-echo TSE sequence with moderate T2-weighting allowed differentiation between malignant and benign hepatic lesions with high sensitivity and specificity.