Continuous prospectively navigated multi-echo GRE for improved BOLD imaging of the kidneys.

The objective of this study is to develop improved methods for renal blood oxygenation level dependent (BOLD) imaging. T2* mapping of the kidneys, or renal BOLD imaging, may depict renal oxygen levels and may be valuable as a noninvasive means of following the progression of renal disease. Current renal BOLD data is limited by imaging in a single breath hold, which results in low resolution and low signal-to-noise ratio (SNR). We compare a new free-breathing renal BOLD method with conventional breath-hold BOLD (BH-BOLD). A multi-echo GRE sequence with continuous prospective respiratory navigation and real-time feedback was developed that allows high resolution and high SNR renal BOLD imaging with constant sequence repetition time (TR) during free-breathing BOLD (FB-BOLD). The sequence was evaluated in 10 normal volunteers and compared with conventional BH-BOLD. Scan time for the FB-BOLD sequence was approximately three minutes, compared with 15 seconds for the BH-BOLD sequence. SNR of source images and residual error of T2* fitting were compared between the two methods. The FB-BOLD sequence produced motion-free T2* maps of the kidneys with SNR 1.9 times higher than BH-BOLD images. Residual error of T2* fitting was consistently lower in the right kidney with FB-BOLD (30% less than BH-BOLD) but higher in the left kidney (80% more than BH-BOLD), likely related to placement of the navigator on the right hemidiaphragm. A free-breathing prospectively navigated renal BOLD sequence allows flexible tradeoff between scan time, resolution, and SNR.

Reduced lateral orbitofrontal cortex volume and suicide behavior in youth with bipolar disorder.

OBJECTIVES: Structural abnormalities in cortical and subcortical regions, including the orbitofrontal cortex (OFC), are altered during brain development in adolescents with bipolar disorder (BD), which may increase risk for suicide. Few studies have examined the neural substrates of suicidal behavior in BD youth. The aim of the present study was to investigate the relationship between suicide behavior and the OFC in youth with BD. METHODS: Thirty-seven participants with BD and 26 non-psychiatric controls, ages 13-21 years, completed a diagnostic interview and mood rating scales. Lifetime symptoms of suicide ideation and behavior were examined using the Columbia Suicide Severity Rating Scale. Participants underwent magnetic resonance imaging on a 3T Siemens Verio scanner. Morphometric analysis of brain images was performed using FreeSurfer. RESULTS: Eighteen participants with BD had a history of suicide attempt (SA). Bipolar youth with a history of SA showed reduced left lateral OFC volumes compared to controls, but there was no difference between BD attempters and non-attempters. Controls and BD non-attempters had significantly greater OFC cortical thickness than BD attempters. Additionally, there was a significant negative correlation between OFC volumes and suicide lethality, demonstrating that as suicide lethality increased, OFC volume in BD youth was reduced. CONCLUSIONS: The OFC is involved in decision-making, impulsivity, and reward circuitry which have shown to be impaired in BD. Reduced OFC volume and its association with lethality of suicide suggest that suicide behavior in BD may be related to the emerging neuroanatomical substrates of the disorder, particularly abnormalities of the OFC.

Cerebral bioenergetic differences measured by phosphorus-31 magnetic resonance spectroscopy between bipolar disorder and healthy subjects living in two different regions suggesting possible effects of altitude.

AIM: Increased oxidative stress in cerebral mitochondria may follow exposure to the systemic hypobaric hypoxia associated with residing at higher altitudes. Because mitochondrial dysfunction is implicated in bipolar disorder (BD) pathophysiology, this may impact the cerebral bioenergetics in BD. In this study, we evaluated the cerebral bioenergetics of BD and healthy control (HC) subjects at two sites, located at sea level and at moderate altitude. METHODS: Forty-three veterans with BD and 33 HC veterans were recruited in Boston (n = 22) and Salt Lake City (SLC; n = 54). Levels of phosphocreatine, ß nucleoside triphosphate (ßNTP), inorganic phosphate, and pH over total phosphate (TP) were measured using phosphorus-31 magnetic resonance spectroscopy in the following brain regions: anterior cingulate cortex and posterior occipital cortex, as well as bilateral prefrontal and occipitoparietal (OP) white matter (WM). RESULTS: A significant main effect of site was found in ßNTP/TP (Boston > SLC) and phosphocreatine/TP (Boston < SLC) in most cortical and WM regions, and inorganic phosphate/TP (Boston < SLC) in OP regions. A main effect analysis of BD diagnosis demonstrated a lower pH in posterior occipital cortex and right OP WM and a lower ßNTP/TP in right prefrontal WM in BD subjects, compared to HC subjects. CONCLUSION: The study showed that there were cerebral bioenergetic differences in both BD and HC veteran participants at two different sites, which may be partly explained by altitude difference. Future studies are needed to replicate these results in order to elucidate the dysfunctional mitochondrial changes that occur in response to hypobaric hypoxia.

Two-dimensional single-shot diffusion-weighted stimulated EPI with reduced FOV for ultrahigh-b radial diffusion-weighted imaging of spinal cord.

PURPOSE: High-resolution diffusion-weighted imaging (DWI) of the spinal cord (SC) is problematic because of the small cross-section of the SC and the large field inhomogeneity. Obtaining the ultrahigh-b DWI poses a further challenge. The purpose of the study was to design and validate two-dimensional (2D) single-shot diffusion-weighted stimulated echo planar imaging with reduced field of view (2D ss-DWSTEPI-rFOV) for ultrahigh-b radial DWI (UHB-rDWI) of the SC. METHODS: A novel time-efficient 2D ss-DWSTEPI-rFOV sequence was developed based on the stimulated echo sequence. Reduced-phase field of view was obtained by using two slice-selective 90 ° radiofrequency pulses in the presence of the orthogonal slice selection gradients. The sequence was validated on a cylindrical phantom and demonstrated on SC imaging. RESULTS: Ultrahigh-b radial diffusion-weighted ( bmax = 7300 s/mm2) images of the SC with greatly reduced distortion were obtained. The exponential plus constant fitting of the diffusion-decay curve estimated the constant fraction (restricted water fraction) as 0.36 ± 0.05 in the SC white matter. CONCLUSION: A novel 2D ss-DWSTEPI-rFOV sequence has been designed and demonstrated for high-resolution UHB-rDWI of localized anatomic structures with significantly reduced distortion induced by nonlinear static field inhomogeneity. Magn Reson Med 77:2167-2173, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Creatine target engagement with brain bioenergetics: a dose-ranging phosphorus-31 magnetic resonance spectroscopy study of adolescent females with SSRI-resistant depression.

Major depressive disorder (MDD) often begins during adolescence and is projected to become the leading cause of global disease burden by the year 2030. Yet, approximately 40 % of depressed adolescents fail to respond to standard antidepressant treatment with a selective serotonin reuptake inhibitor (SSRI). Converging evidence suggests that depression is related to brain mitochondrial dysfunction. Our previous studies of MDD in adult and adolescent females suggest that augmentation of SSRI pharmacotherapy with creatine monohydrate (CM) may improve MDD outcomes. Neuroimaging with phosphorus-31 magnetic resonance spectroscopy ((31)P-MRS) can measure the high-energy phosphorus metabolites in vivo that reflect mitochondrial function. These include phosphocreatine (PCr), a substrate for the creatine kinase reaction that produces adenosine triphosphate. As part of the National Institute of Mental Health's experimental medicine initiative, we conducted a placebo-controlled dose-ranging study of adjunctive CM for adolescent females with SSRI-resistant MDD. Participants were randomized to receive placebo or CM 2, 4 or 10 g daily for 8 weeks. Pre- and post-treatment (31)P-MRS scans were used to measure frontal lobe PCr, to assess CM's target engagement with cerebral energy metabolism. Mean frontal lobe PCr increased by 4.6, 4.1 and 9.1 % in the 2, 4 and 10 g groups, respectively; in the placebo group, PCr fell by 0.7 %. There was no group difference in adverse events, weight gain or serum creatinine. Regression analysis of PCr and depression scores across the entire sample showed that frontal lobe PCr was inversely correlated with depression scores (p = 0.02). These results suggest that CM achieves target engagement with brain bioenergetics and that the target is correlated with a clinical signal. Further study of CM as a treatment for adolescent females with SSRI-resistant MDD is warranted.

Synchronous Radial 1H and 23Na Dual-Nuclear MRI on a Clinical MRI System, Equipped With a Broadband Transmit Channel.

The purpose of this work was to synchronously acquire proton (1H) and sodium (23Na) image data on a 3T clinical MRI system within the same sequence, without internal modification of the clinical hardware, and to demonstrate synchronous acquisition with 1H/23Na-GRE imaging with Cartesian and radial k-space sampling. Synchronous dual-nuclear imaging was implemented by: mixing down the 1H signal so that both the 23Na and 1H signal were acquired at 23Na frequency by the conventional MRI system; interleaving 1H/23Na transmit pulses in both Cartesian and radial sequences; and using phase stabilization on the 1H signal to remove mixing effects. The synchronous 1H/23Na setup obtained images in half the time necessary to sequentially acquire the same 1H and 23Na images with the given setup and parameters. Dual-nuclear hardware and sequence modifications were used to acquire 23Na images within the same sequence as 1H images, without increases to the 1H acquisition time. This work demonstrates a viable technique to acquire 23Na image data without increasing 1H acquisition time using minor additional custom hardware, without requiring modification of a commercial scanner with multinuclear capability.

Decreased brain PME/PDE ratio in bipolar disorder: a preliminary (31) P magnetic resonance spectroscopy study.

OBJECTIVES: The aim of the present study was to measure brain phosphorus-31 magnetic resonance spectroscopy ((31) P MRS) metabolite levels and the creatine kinase reaction forward rate constant (kf ) in subjects with bipolar disorder (BD). METHODS: Subjects with bipolar euthymia (n = 14) or depression (n = 11) were recruited. Healthy comparison subjects (HC) (n = 23) were recruited and matched to subjects with BD on age, gender, and educational level. All studies were performed on a 3-Tesla clinical magnetic resonance imaging system using a (31) P/(1) H double-tuned volume head coil. (31) P spectra were acquired without (1) H-decoupling using magnetization-transfer image-selected in vivo spectroscopy. Metabolite ratios from a brain region that includes the frontal lobe, corpus callosum, thalamus, and occipital lobe are expressed as a percentage of the total phosphorus (TP) signal. Brain pH was also investigated. RESULTS: Beta-nucleoside-triphosphate (ß-NTP/TP) in subjects with bipolar depression was positively correlated with kf (p = 0.039, r(2) = 0.39); similar correlations were not observed in bipolar euthymia or HC. In addition, no differences in kf and brain pH were observed among the three diagnostic groups. A decrease in the ratio of phosphomonoesters to phosphodiesters (PME/PDE) was observed in subjects with bipolar depression relative to HC (p = 0.032). We also observed a trend toward an inverse correlation in bipolar depression characterized by decreased phosphocreatine and increased depression severity. CONCLUSIONS: In our sample, kf was not altered in the euthymic or depressed mood state in BD. However, decreased PME/PDE in subjects with bipolar depression was consistent with differences in membrane turnover. These data provide preliminary support for alterations in phospholipid metabolism and mitochondrial function in bipolar depression.

Gender differences in the effect of tobacco use on brain phosphocreatine levels in methamphetamine-dependent subjects.

BACKGROUND: A high prevalence of tobacco smoking has been observed in methamphetamine users, but there have been no in vivo brain neurochemistry studies addressing gender effects of tobacco smoking in methamphetamine users. Methamphetamine addiction is associated with increased risk of depression and anxiety in females. There is increasing evidence that selective analogues of nicotine, a principal active component of tobacco smoking, may ease depression and improve cognitive performance in animals and humans. OBJECTIVES: To investigate the effects of tobacco smoking and gender on brain phosphocreatine (PCr) levels, a marker of brain energy metabolism reported to be reduced in methamphetamine-dependent subjects. METHODS: Thirty female and 27 male methamphetamine-dependent subjects were evaluated with phosphorus-31 magnetic resonance spectroscopy ((31)P-MRS) to measure PCr levels within the pregenual anterior cingulate, which has been implicated in methamphetamine neurotoxicity. RESULTS: Analysis of covariance revealed that there were statistically significant slope (PCr versus lifetime amount of tobacco smoking) differences between female and male methamphetamine-dependent subjects (p = 0.03). In females, there was also a statistically significant interaction between lifetime amounts of tobacco smoking and methamphetamine in regard to PCr levels (p = 0.01), which suggests that tobacco smoking may have a more significant positive impact on brain PCr levels in heavy, as opposed to light to moderate, methamphetamine-dependent females. CONCLUSION: These results indicate that tobacco smoking has gender-specific effects in terms of increased anterior cingulate high energy PCr levels in methamphetamine-dependent subjects. Cigarette smoking in methamphetamine-dependent women, particularly those with heavy methamphetamine use, may have a potentially protective effect upon neuronal metabolism.

Creatine as a Novel Treatment for Depression in Females Using Methamphetamine: A Pilot Study.

OBJECTIVE: Depression among methamphetamine users is more prevalent in females than males, but gender-specific treatment options for this comorbidity have not been described. Reduced brain phosphocreatine levels have been shown to be lower in female methamphetamine users compared to males, and, of relevance, studies have demonstrated an association between treatment-resistant depression and reduced brain phosphocreatine concentrations. The nutritional supplement creatine monohydrate has been reported to reduce symptoms of depression in female adolescents and adults taking antidepressants, as well as to increase brain phosphocreatine in healthy volunteers. Therefore, the purpose of this pilot study was to investigate creatine monohydrate as a treatment for depression in female methamphetamine users. METHODS: Fourteen females with depression and comorbid methamphetamine dependence were enrolled in an 8-week open label trial of 5 g of daily creatine monohydrate and of these 14, 11 females completed the study. Depression was measured using the Hamilton Depression Rating Scale (HAMD) and brain phosphocreatine levels were measured using phosphorus magnetic resonance spectroscopy pre- and post-creatine treatment. Secondary outcome measures included anxiety symptoms, measured with the Beck Anxiety Inventory (BAI), as well as methamphetamine use, monitored by twice weekly urine drug screens and self-reported use. RESULTS: The results of a linear mixed effects repeated measures model showed significantly reduced HAMD and BAI scores as early as week 2 when compared to baseline scores. This improvement was maintained through study completion. Brain phosphocreatine concentrations were higher at the second phosphorus magnetic resonance spectroscopy scan compared to the baseline scan; Mbaseline = 0.223 (SD = 0.013) vs. Mpost-treatment = 0.233 (SD = 0.009), t (9) = 2.905, p <.01, suggesting that creatine increased phosphocreatine levels. Also, a reduction in methamphetamine positive urine drug screens of greater than 50% was observed by week 6. Finally, creatine was well tolerated and adverse events that were related to gastrointestinal symptoms and muscle cramping were determined as possibly related to creatine. CONCLUSIONS: The current study suggests that creatine treatment may be a promising therapeutic approach for females with depression and comorbid methamphetamine dependence. This study is registered on clinicaltrials.gov (NCT01514630).

The Utility of Magnetic Resonance Spectroscopy for Understanding Substance Use Disorders: A Systematic Review of the Literature.

The aim of this article is to present a systematic review of magnetic resonance spectroscopy (MRS) studies of substance use disorders. As a noninvasive and nonionizing imaging technique, MRS is being widely used in substance abuse research to evaluate the effects substances of abuse have on brain chemistry. Nearly 40 peer-reviewed research articles that focused on the utility of MRS in alcohol, methamphetamine, 3,4-methylenedioxymethamphetamine, cocaine, opiates, opioids, marijuana, and nicotine use disorders were reviewed. Findings indicate inconsistencies with respect to alterations in brain chemistry within each substance of abuse, and the most consistent finding across substances was decreased N-acetylaspartate and choline levels with chronic alcohol, methamphetamine, and nicotine use. Variation in the brain regions studied, imaging technique, as well as small sample sizes might explain the discrepancies in findings within each substance. Future well-designed MRS studies offer promise in examining novel treatment approaches in substance use disorders.

In vivo T(2) relaxation time measurement with echo-time averaging.

The accuracy of metabolite concentrations measured using in vivo proton ((1) H) MRS is enhanced following correction for spin-spin (T2 ) relaxation effects. In addition, metabolite proton T2 relaxation times provide unique information regarding cellular environment and molecular mobility. Echo-time (TE) averaging (1) H MRS involves the collection and averaging of multiple TE steps, which greatly simplifies resulting spectra due to the attenuation of spin-coupled and macromolecule resonances. Given the simplified spectral appearance and inherent metabolite T2 relaxation information, the aim of the present proof-of-concept study was to develop a novel data processing scheme to estimate metabolite T2 relaxation times from TE-averaged (1) H MRS data. Spectral simulations are used to validate the proposed TE-averaging methods for estimating methyl proton T2 relaxation times for N-acetyl aspartate, total creatine, and choline-containing compounds. The utility of the technique and its reproducibility are demonstrated using data obtained in vivo from the posterior-occipital cortex of 10 healthy control subjects. Compared with standard methods, distinct advantages of this approach include built-in macromolecule resonance attenuation, in vivo T2 estimates closer to reported values when maximum TE ≈ T2 , and the potential for T2 calculation of metabolite resonances otherwise inseparable in standard (1) H MRS spectra recorded in vivo.

An Integrated Analysis of Anatomical and Sugar Contents Identifies How Night Temperatures Regulate the Healing Process of Oriental Melon Grafted onto Pumpkin.

Graft healing is a complex process affected by environmental factors, with temperature being one of the most important influencing factors. Here, oriental melon grafted onto pumpkin was used to study changes in graft union formation and sugar contents at the graft interface under night temperatures of 18 °C and 28 °C. Histological analysis suggested that callus formation occurred 3 days after grafting with a night temperature of 28 °C, which was one day earlier than with a night temperature of 18 °C. Vascular reconnection with a night temperature of 28 °C was established 2 days earlier than with a night temperature of 18 °C. Additionally, nine sugars were significantly enriched in the graft union, with the contents of sucrose, trehalose, raffinose, D-glucose, D-fructose, D-galactose, and inositol initially increasing but then decreasing. Furthermore, we also found that exogenous glucose and fructose application promotes vascular reconnection. However, exogenous sucrose application did not promote vascular reconnection. Taken together, our results reveal that elevated temperatures improve the process of graft union formation through increasing the contents of sugars. This study provides information to develop strategies for improving grafting efficiency under low temperatures.

Tobacco nicotine promotes TRAIL resistance in lung cancer through SNHG5.

Tobacco nicotine use is carcinogenic and a well-known risk factor for lung cancer. However, whether tobacco nicotine can induce drug resistance in lung cancer is not clear. The objective of the present study was to identify the TNF-related apoptosis-inducing ligand (TRAIL) resistance of long noncoding RNAs (lncRNAs) that are differentially expressed in smokers and nonsmokers with lung cancer. The results suggested that the nicotine upregulated small nucleolar RNA host gene 5 (SNHG5) and markedly decreased the levels of cleaved caspase-3. The present study found that cytoplasm lncRNA SNHG5 overexpression was associated with TRAIL resistance in lung cancer and that SNHG5 can interact with X-linked inhibitor of apoptosis protein to promote TRAIL resistance. Therefore, nicotine promoted TRAIL resistance in lung cancer through SNHG5/X-linked inhibitor of apoptosis protein.

Efficacy of Streptomyces murinus JKTJ-3 in Suppression of Pythium Damping-Off of Watermelon.

Damping-off caused by Pythium aphanidermatum (Pa) is one of the most destructive diseases for watermelon seedlings. Application of biological control agents against Pa has attracted the attention of many researchers for a long time. In this study, the actinomycetous isolate JKTJ-3 with strong and broad-spectrum antifungal activity was screened from 23 bacterial isolates. Based on the morphological, cultural, physiological, and biochemical characteristics as well as the feature of 16S rDNA sequence, isolate JKTJ-3 was identified as Streptomyces murinus. We investigated the biocontrol efficacy of isolate JKTJ-3 and its metabolites. The results revealed that seed and substrate treatments with JKTJ-3 cultures showed a significant inhibitory effect on watermelon damping-off disease. Seed treatment with the JKTJ-3 cultural filtrates (CF) displayed higher control efficacy compared to the fermentation cultures (FC). Treatment of the seeding substrate with the wheat grain cultures (WGC) of JKTJ-3 exhibited better control efficacy than that of the seeding substrate with the JKTJ-3 CF. Moreover, the JKTJ-3 WGC showed the preventive effect on suppression of the disease, and the efficacy increased with increase in the inoculation interval between the WGC and Pa. Production of the antifungal metabolite actinomycin D by isolate JKTJ-3 and cell-wall-degrading enzymes such as ß-1,3-glucanase and chitosanase were probably the mechanisms for effective control of watermelon damping-off. It was shown for the first time that S. murinus can produce anti-oomycete substances including chitinase and actinomycin D. This is the first report about S. murinus used as biocontrol agent against watermelon damping-off caused by Pa.

Effects of gadolinium chelate on the evolution of the nanoscale structure in peptide hydrogels.

Small-angle X-ray scattering (SAXS) was used to monitor peptide hydrogelation with and without the MRI contrast agent gadolinium chelate (Gd(III)-chelate). The gelators are a pair of decapeptides that are self-repulsive but mutually attractive. Gd(III)-chelate was either free or covalently bound to one of the decapeptides. Free and conjugated Gd(III)-chelate have the opposite effects on peptide gelation: free Gd(III)-chelate slows down gelation while having little effect on the cross-sectional area of peptide fibers; covalently conjugated Gd(III)-chelate speeds up gelation and results in peptide fibers with significantly greater cross-sectional area. After 24 h of gelation, the cross-sectional areas of hydrogels with no Gd(III)-chelate, with free Gd(III)-chelate and with conjugated Gd(III) chelate are 3700, 3800, and 6300 Å(2), respectively. Free Gd(III)-chelate is not incorporated into peptide fibers and remains in solution with little effect on MRI intensity upon gelation. In contrast, covalently conjugated Gd(III)-chelate is not only incorporated into peptide fibers, but further aggregates toward the center of the peptide fibers. In conclusion, to visualize hydrogelation using (1)H MRI, it is necessary to conjugate Gd(III)-chelate to the material covalently and use T(2)-weighted imaging.

Frontal lobe bioenergetic metabolism in depressed adolescents with bipolar disorder: a phosphorus-31 magnetic resonance spectroscopy study.

OBJECTIVES: To compare the concentrations of high-energy phosphorus metabolites associated with mitochondrial function in the frontal lobe of depressed adolescents with bipolar disorder (BD) and healthy controls (HC). METHODS: We used in vivo phosphorus-31 magnetic resonance spectroscopy ((31) P-MRS) at 3 Tesla to measure phosphocreatine (PCr), beta-nucleoside triphosphate (ß-NTP), inorganic phosphate (Pi), and other neurometabolites in the frontal lobe of eight unmedicated and six medicated adolescents with bipolar depression and 24 adolescent HCs. RESULTS: Analysis of covariance, including age as a covariate, revealed differences in PCr (p=0.037), Pi (p=0.017), and PCr/Pi (p=0.002) between participant groups. Percentage neurochemical differences were calculated with respect to mean metabolite concentrations in the HC group. Post-hoc Tukey-Kramer analysis showed that unmedicated BD participants had decreased Pi compared with both HC (17%; p=0.038) and medicated BD (24%; p=0.022). The unmedicated BD group had increased PCr compared with medicated BD (11%; p=0.032). The PCr/Pi ratio was increased in unmedicated BD compared with HC (24%; p=0.013) and with medicated BD (39%; p=0.002). No differences in ß-NTP or pH were observed. CONCLUSIONS: Our results support the view that frontal lobe mitochondrial function is altered in adolescent BD and may have implications for the use of Pi as a biomarker. These findings join volumetric studies of the amygdala, and proton MRS studies of n-acetyl aspartate in pointing to potential differences in neurobiology between pediatric and adult BD.

The complete mitochondrial genome of Fannia canicularis (Diptera: Fanniidae).

Fannia canicularis (Linnaeus, 1761) is a species from the family Fanniidae. In this study, we sequenced and analyzed the complete mitochondrial genome of F. canicularis for the first time. The circular mitogenome is 15,826 bp in length, and includes 13 protein-coding genes (PCGs), 22 transfer RNA genes, two ribosomal RNA genes, and a non-coding control region. The family Fanniidae formed a monophyletic clade in the phylogenetic tree based on 13 concatenated PCGs, sister to three other families in Diptera.

Proton magnetic resonance spectroscopy (MRS) in individuals with internet gaming.

Background: Various comorbid psychiatric diagnoses, including attention deficit hyperactivity disorder (ADHD), have been reported in individuals with internet gaming disorder (IGD). Prior research has shown alterations in brain metabolites, including N-acetylaspartate (NAA), and combined glutamate and glutamine in patients with ADHD that were similar to those observed in patients with IGD. We hypothesized that the decreased NAA levels in the IGD group would be associated with a history of ADHD. Methods: Forty adults participated in this study. Participants were classified as having a high risk for IGD if they had a total score higher than 21 on the IGD Scale-short form. Proton magnetic resonance spectroscopy (1H-MRS) and high-resolution structural magnetic resonance imaging (MRI) data were acquired using a 3 Tesla Siemens Prisma scanner system. Results: Levels of NAA within the right prefrontal cortex were lower in the IGD group than those observed in the control group. In a multiple linear regression analysis, internet addiction test scores and history of ADHD were shown to predict increased game play. In addition, history of ADHD predicted lower levels of NAA within the right prefrontal cortex. Conclusion: The preliminary results of current study suggest a mediating effect of ADHD on the severity of internet game play as well as the levels of NAA within the dorsolateral prefrontal cortex (DLPFC). The inclusion of ADHD in IGD research is important and deserving of further consideration.

Measurement of creatine kinase reaction rate in human brain using magnetization transfer image-selected in vivo spectroscopy (MT-ISIS) and a volume ³¹P/¹H radiofrequency coil in a clinical 3-T MRI system.

High-energy phosphate metabolism, which allows the synthesis and regeneration of adenosine triphosphate (ATP), is a vital process for neuronal survival and activity. In particular, creatine kinase (CK) serves as an energy reservoir for the rapid buffering of ATP levels. Altered CK enzyme activity, reflecting compromised high-energy phosphate metabolism or mitochondrial dysfunction in the brain, can be assessed using magnetization transfer (MT) MRS. MT (31)P MRS has been used to measure the forward CK reaction rate in animal and human brain, employing a surface radiofrequency coil. However, long acquisition times and excessive radiofrequency irradiation prevent these methods from being used routinely for clinical evaluations. In this article, a new MT (31)P MRS method is presented, which can be practically used to measure the CK forward reaction rate constant in a clinical MRI system employing a volume head (31)P coil for spatial localization, without contamination from the scalp muscle, and an acquisition time of 30 min. Other advantages associated with the method include radiofrequency homogeneity within the regions of interest of the brain using a volume coil with image-selected in vivo spectroscopy localization, and reduction of the specific absorption rate using nonadiabatic radiofrequency pulses for MT saturation. The mean value of k(f) was measured as 0.320 ± 0.075 s(-1) from 10 healthy volunteers with an age range of 18-40 years. These values are consistent with those obtained using earlier methods, and the technique may be used routinely to evaluate energetic processes in the brain on a clinical MRI system.

In vivo and ex vivo measurements of the mean ADC values of lipid necrotic core and hemorrhage obtained from diffusion weighted imaging in human atherosclerotic plaques.

PURPOSE: To determine the apparent diffusion coefficient (ADC) values of lipid and hemorrhage in atherosclerotic plaque in human carotid arteries in vivo and compare the values obtained from ex vivo carotid endarterectomy specimens. MATERIALS AND METHODS: In vivo diffusion-weighted imaging (DWI) of carotid plaques was performed using a 2D single shot Interleaved Multislice Inner Volume Diffusion Weighted Echo Planar Imaging (2D ss-IMIV DWEPI) on 8 subjects who subsequently underwent carotid endarterectomy. A total of 32 slices used to construct the ADC maps were reviewed for the measurement of the mean ADC values in vessel wall, hemorrhage, and lipid necrotic core. The 8 endarterectomy specimens were scanned using by three-dimensional ms-IV-DWEPI. After the ADC maps were created, the mean ADC values in the same locations selected for in vivo values were calculated. RESULTS: The mean ADC values obtained from in vivo DWI in normal vessel wall, lipid rich core, and hemorrhage were 1.27 ± 0.16, 0.38 ± 0.1, and 0.98 ± 0.25 × 10(-3) mm(2)/s, respectively. The mean ADC values in ex vivo lipid necrotic core, and hemorrhage were 0.33 ± 0.08, 1.28 ± 0.10 × 10(-3) mm(2)/s, respectively. These components mean ADC values obtained from in vivo and ex vivo ADC maps were compared. CONCLUSION: ADC values of the carotid plaque components in vivo are consistent with values obtained from ex vivo endarterectomy specimens. The ability to obtain consistent plaque ADC values in vivo indicates that this technique could be an integral part of the basis for plaque component identification in conjunction with other MRI techniques.