Hyperandrogenism in normal weight PCOS women is associated with preferential intra-abdominal fat deposition and an increased population of small SC abdominal adipocytes that could constrain SC adipose storage and promote metabolic dysfunction.

Purpose: To estimate precontrast tissue parameter (T 10 ) using fast spin echo (FSE) and to quantify physiological and hemodynamic parameters with leakage correction using T 1 -weighted dynamic contrast-enhanced (DCE) perfusion imaging. Materials and Methods:Voxel-wise T 10 computation was performed followed by the analysis of T 1 -weighted DCE perfusion data for the conversion of signal intensity time curve to concentration time curve, estimation of hemodynamic and physiological perfusion indices, and a method for leakage correction. Validations of accuracy of the computations have also been carried out. Results:The computed T 10 and hemodynamic perfusion indices in normal white and gray matter were in good agreement with the literature values. Physiological perfusion indices in these regions were found negligible, validating computations. Cerebral blood volume (CBV) values change negligibly over the length of concentration time curve in white matter, gray matter, and lesion (CBV corrected ), while CBV uncorrected (lesion) shows linear increase over time.Conclusion: T 1 -weighted DCE perfusion data along with FSE-based T 1 estimation can be used for an accurate estimation of hemodynamic and physiological perfusion indices.

Despite the success of antiretroviral therapy (ART), perinatally infected HIV remains a major health problem worldwide. Although advance neuroimaging studies have investigated structural brain changes in HIV-infected adults, regional gray matter (GM) and white matter (WM) volume changes have not been reported in perinatally HIV-infected adolescents and young adults. In this cross-sectional study, we investigated regional GM and WM changes in 16 HIV-infected youths receiving ART (age 17.0 ± 2.9 years) compared with age-matched 14 healthy controls (age 16.3 ± 2.3 years) using magnetic resonance imaging (MRI)-based high-resolution T1-weighted images with voxel based morphometry (VBM) analyses. White matter atrophy appeared in perinatally HIV-infected youths in brain areas including the bilateral posterior corpus callosum (CC), bilateral external capsule, bilateral ventral temporal WM, mid cerebral peduncles, and basal pons over controls. Gray matter volume increase was observed in HIV-infected youths for several regions including the left superior frontal gyrus, inferior occipital gyrus, gyrus rectus, right mid cingulum, parahippocampal gyrus, bilateral inferior temporal gyrus, and middle temporal gyrus compared with controls. Global WM and GM volumes did not differ significantly between groups. These results indicate WM injury in perinatally HIV-infected youths, but the interpretation of the GM results, which appeared as increased regional volumes, is not clear. Further longitudinal studies are needed to clarify if our results represent active ongoing brain infection or toxicity from HIV treatment resulting in neuronal cell swelling and regional increased GM volume. Our findings suggest that assessment of regional GM and WM volume changes, based on VBM procedures, may be an additional measure to assess brain integrity in HIV-infected youths and to evaluate success of current ART therapy for efficacy in the brain.

Objective:This study examined neurologic abnormalities (as measured by proton magnetic resonance spectroscopy imaging and diffusion tensor imaging), neurocognitive performance, and fatigue among a sample of adults with hepatitis C virus (HCV). We hypothesized that HCV+ individuals would demonstrate structural brain abnormalities and neurocognitive compromise consistent with frontostriatal dysfunction as well as increased fatigue compared to controls.Method:Participants were 76 individuals diagnosed with HCV and 20 controls who underwent a comprehensive neurocognitive evaluation and clinical assessments. A subset of the HCV+ participants (n = 29) and all controls underwent MRI.Results:Individuals diagnosed with chronic HCV infection demonstrated greater fractional anisotropy in the striatum as well as greater mean diffusivity in the fronto-occiptal fasciculus and external capsule compared to HCV− controls. HCV+ participants also demonstrated lower levels of N-acetylaspartate in bilateral parietal white matter and elevations in myo-inosital (mI) in bilateral frontal white matter compared to HCV− controls (all p values < 0.05). HCV+ participants also demonstrated significantly poorer neuropsychological performance, particularly in processing speed and verbal fluency. HCV+ patients reported higher levels of fatigue than controls, and fatigue was significantly correlated with diffusivity in the superior fronto-occipital fasciculus, elevations in mI in frontal white matter, and overall cognitive performance.Conclusions:Our results suggest that HCV-associated neurologic complications disrupt frontostriatal structures, which may result in increased fatigue and poorer cognitive performance, particularly in those cognitive domains regulated by frontostriatal regions.

The effects of HIV on brain metabolites and cognitive function are not well understood. Sixteen HIV+youths (15 vertical, 1 transfusion transmissions) receiving combination antiretroviral therapy and 14 age-matched HIV-youths (13–25 years of age) were evaluated with brain two-dimensional (2D) magnetic resonance spectroscopy (MRS) at 3 Tesla (T) and a neuropsychological battery that assessed three cognitive domains (attention/processing speed, psychomotor ability, and executive function). The relationship between brain metabolite ratios and cognitive performance was explored. Compared to HIV− controls, HIV+subjects had higher sycllo-inositol (Scy)/total creatine (tCr) (+32%, p=0.016) and higher Scy/total choline (tCho) (+31%, p=0.018) on 2D-MRS in the right frontal lobe. HIV+ subjects also had higher glutamate (Glu)/tCr (+13%, p=0.022) and higher Glu/tCho (+15%, p=0.048) than controls. HIV+subjects demonstrated poorer attention/processing speed (p=0.011, d=1.03) but similar psychomotor and executive function compared to HIV− controls. The attention/processing score also correlated negatively with the ratio of N-acetylaspartate (NAA) to tCr on 2D-MRS (r=−0.75, p=0.0019) in the HIV− controls, but not in the HIV+ subjects (Fisher’s r-z transformation, p<0.05). Our results suggest that attention/processing speed is impacted by early HIV infection and is associated with right hemisphere NAA/tCr. Scy and Glu ratios are also potential markers of brain health in chronic, lifelong HIV infection in perinatally infected youths receiving antiretroviral therapy.

BACKGROUND AND PURPOSE Echo-planar J-resolved spectroscopic imaging is a fast spectroscopic technique to record the biochemical information in multiple regions of the brain, but for clinical applications, time is still a constraint. Investigations of neural injury in obstructive sleep apnea have revealed structural changes in the brain, but determining the neurochemical changes requires more detailed measurements across multiple brain regions, demonstrating a need for faster echo-planar J-resolved spectroscopic imaging. Hence, we have extended the compressed sensing reconstruction of prospectively undersampled 4D echo-planar J-resolved spectroscopic imaging to investigate metabolic changes in multiple brain locations of patients with obstructive sleep apnea and healthy controls. MATERIALS AND METHODS Nonuniform undersampling was imposed along 1 spatial and 1 spectral dimension of 4D echo-planar J-resolved spectroscopic imaging, and test-retest reliability of the compressed sensing reconstruction of the nonuniform undersampling data was tested by using a brain phantom. In addition, 9 patients with obstructive sleep apnea and 11 healthy controls were investigated by using a 3T MR imaging/MR spectroscopy scanner. RESULTS Significantly reduced metabolite differences were observed between patients with obstructive sleep apnea and healthy controls in multiple brain regions: NAA/Cr in the left hippocampus; total Cho/Cr and Glx/Cr in the right hippocampus; total NAA/Cr, taurine/Cr, scyllo-Inositol/Cr, phosphocholine/Cr, and total Cho/Cr in the occipital gray matter; total NAA/Cr and NAA/Cr in the medial frontal white matter; and taurine/Cr and total Cho/Cr in the left frontal white matter regions. CONCLUSIONS The 4D echo-planar J-resolved spectroscopic imaging technique using the nonuniform undersampling–based acquisition and compressed sensing reconstruction in patients with obstructive sleep apnea and healthy brain is feasible in a clinically suitable time. In addition to brain metabolite changes previously reported by 1D MR spectroscopy, our results show changes of additional metabolites in patients with obstructive sleep apnea compared with healthy controls.

Purpose: To investigate functional changes in prostate cancer patients with three pathologically proven different Gleason scores (GS) (3þ3, 3þ4, and 4þ3) using magnetic resonance spectroscopic imaging (MRSI) and diffusionweighted imaging (DWI). Materials and Methods:In this study MRSI and DWI data were acquired in 41 prostate cancer patients using a 1.5T MRI scanner with a body matrix combined with an endorectal coil. The metabolite ratios of (ChoþCr)/Cit were calculated from the peak integrals of total choline (Cho), creatine (Cr), and citrate (Cit) in MRSI. Apparent diffusion coefficient (ADC) values were derived from DWI for three groups of Gleason scores. The sensitivity and specificity of MRSI and DWI in patients were calculated using receiver operating characteristic curve (ROC) analysis. Results:The mean and standard deviation of (ChoþCr)/ Cit ratios of GS 3þ3, GS 3þ4, and GS 4þ3 were: 0.44 6 0.02, 0.56 6 0.06, and 0.88 6 0.11, respectively. For the DWI, the mean and standard deviation of ADC values in GS 3þ3, GS 3þ4, and GS 4þ3 were: 1.13 6 0.11, 0.97 6 0.10, and 0.83 6 0.08 mm 2 /sec, respectively. Statistical significances were observed between the GS and metabolite ratio as well as ADC values and GS.Conclusion: Combined MRSI and DWI helps identify the presence and the proportion of aggressive cancer (ie, Gleason grade 4) that might not be apparent on biopsy sampling. This information can guide subsequent rebiopsy management, especially for active surveillance programs.

Age-dependent changes in the normal cerebral white matter have been reported; however, there is no study on normal cerebellar white matter maturation in developing brain using diffusion tensor imaging (DTI). We performed DTI in 21 children who had normal neurological assessment along with no evidence of any abnormality on imaging. The aim of this study was to compare the age-related changes in fractional anisotropy (FA) and mean diffusivity (MD) quantified from cerebral white matter (splenium and genu of the corpus callosum and posterior limb of the internal capsule) and cerebellar white matter (middle cerebellar peduncles, superior cerebellar peduncles, and inferior cerebellar peduncles) regions in healthy children ranging in age from birth to 132 months. Log-linear regression model showed best fit to describe the age-related changes in FA and MD both for cerebral and cerebellar white matter. In cerebral white matter, an initial sharp increase in FA was observed up to the age of 24 months followed by a gradual increase up to 132 months. In cerebellar white matter, sharp increase in FA was observed up to 36 months, which then followed a gradual increase. However, MD showed a sharp decrease in cerebral white matter up to 24 months followed by a more gradual decrease thereafter, while in cerebellar white matter after an initial decrease (6 months), it followed a stable pattern. This study provides normative database of brain white matter development from neonates to childhood. This quantitative information may be useful for assessing brain maturation in patients with developmental delay of the cerebral and cerebellar white matter.