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ObjectA novel method of estimating metabolite T1 relaxation times using MR spectroscopic imaging (MRSI) is proposed. As opposed to conventional single-voxel metabolite T1 estimation methods, this method investigates regional and gray matter (GM)/white matter (WM) differences in metabolite T1 by taking advantage of the spatial distribution information provided by MRSI.Material and methodsThe method, validated by Monte Carlo studies, involves a voxel averaging to preserve the GM/WM distribution, a non-linear least squares fit of the metabolite T1 and an estimation of its standard error by bootstrapping. It was applied in vivo to estimate the T1 of N-acetyl compounds (NAA), choline, creatine and myo-inositol in eight normal volunteers, at 1.5 T, using a short echo time 2D-MRSI slice located above the ventricles.ResultsWM-T 1,NAA was significantly (P < 0.05) longer in anterior regions compared to posterior regions of the brain. The anterior region showed a trend of a longer WM T1 compared to GM for NAA, creatine and myo-Inositol. Lastly, accounting for the bootstrapped standard error estimate in a group mean T1 calculation yielded a more accurate T1 estimation.ConclusionThe method successfully measured in vivo metabolite T1 using MRSI and can now be applied to diseased brain.

Purpose: To establish the incidence, size, zonal location and Gleason Score(GS)/Gleason Grade Group(GG) of sparse versus dense prostate cancer (PCa) lesions and to identify the imaging characteristics of sparse versus dense cancers on multiparametric MRI (mpMRI)., Methods: Seventy-six men with untreated PCa were scanned prior to prostatectomy with endorectal-coil 3 T MRI including T2-weighted imaging, diffusion-weighted imaging and dynamic contrast-enhanced MRI. Cancerous regions were outlined and graded on the whole-mount, processed specimens, with tissue compositions estimated. Regions with cancer comprising <50 % and ≥ 50 % of the tissue were considered sparse and dense respectively. Regions of interest (ROI) were manually drawn on T2-weighted MRI. Within each patient, area-weighted ROI averages were calculated for each imaging measure for each tissue type, GS/GG, and sparse/dense composition., Results: A large number of cancer regions were identified on histopathology (n = 1193: 939 (peripheral zone (PZ)) and 254 (transition zone (TZ))). Thirty-seven percent of these lesions were sparse. Sparse lesions were primarily low-grade with the majority of PZ and 100 % of TZ sparse lesions ≤GS3 + 3/GG1. Dense lesions were significantly larger than sparse lesions in both PZ and TZ, p < 0.0001. On imaging, 246/45 PZ and 109/8 TZ dense/sparse 2D cancerous ROIs were drawn. Sparse GS3 + 3 and sparse ≥GS3 + 4 cancers did not have significantly different MRI intensities to dense GS3 + 3 cancers, while sparse GS3 + 3/GG1 cancers differed from benign, p < 0.05., Conclusion: Histopathologically identified prostate cancer lesions were sparse in 37 % of cases. Sparse cancers were entirely low grade in TZ and predominantly low-grade in PZ and generally small, thus likely posing lower risk for spread and progression than dense lesions. Sparse lesions were not distinguishable from dense lesions on mpMRI, but could be distinguished from benign tissues., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: People with human immunodeficiency virus (HIV) (PWH) have an increased risk of cardiovascular disease (CVD). Cardiac magnetic resonance (CMR) has documented higher myocardial fibrosis, inflammation, and steatosis in PWH, but studies have mostly relied on healthy volunteers as comparators and focused on men., Methods: We investigated the associations of HIV and HIV-specific factors with CMR phenotypes in female participants enrolled in the Women's Interagency HIV Study's New York and San Francisco sites. Primary phenotypes included myocardial native (n) T1 (fibro-inflammation), extracellular volume fraction (fibrosis), and triglyceride content (steatosis). Associations were evaluated with multivariable linear regression, and results pooled or meta-analyzed across centers., Results: Among 261 women with HIV (WWH, N = 362), 76.2% had undetectable viremia at CMR. For the 82.8% receiving continuous antiretroviral therapy (ART) in the preceding 5 years, adherence was 51.7%, and 69.4% failed to achieve persistent viral suppression (40.7% with peak viral load <200 cp/mL). Overall, WWH showed higher nT1 than women without HIV after full adjustment. This higher nT1 was more pronounced in those with antecedent or current viremia or nadir CD4+ count <200 cells/μL, with the latter also associated with higher extracellular volume fraction. WWH and current CD4+ count <200 cells/μL had less cardiomyocyte steatosis. Cumulative exposure to specific ART showed no associations., Conclusions: Compared with sociodemographically similar women without HIV, WWH on ART exhibit higher myocardial fibro-inflammation, which is more prominent with unsuppressed viremia or CD4+ lymphopenia. These findings support the importance of improved ART adherence strategies, along with better understanding of latent infection, to mitigate cardiac end-organ damage in this population., Competing Interests: Potential conflicts of interest. J. R. K. reports stock ownership in Abbvie, Abbott, Bristol Myers Squibb, Johnson & Johnson, Lilly, Medtronic, Merck, and Pfizer. K. O. is president of the Society for Cardiovascular Magnetic Resonance (2023–2024). Y. K. reports receiving speaker fees from CANON Medical Systems. J. M. L. reports editing royalties for cardiovascular textbook from Oxford University Press. P. C. T. reports grants from Merck and Gilead paid to their institution, payment for integritas CME presentation, participation on the STAR cohort Scientific Advisory Board, STAR cohort Scientific Advisory Board, and BIRCWH K12 External Scientific Advisory Board. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Multi-parametric MRI (mpMRI) has proven itself a clinically useful tool to assess prostate cancer (PCa). Our objective was to generate PCa risk maps to quantify the volume and location of both all PCa and high grade (Gleason grade group ≥ 3) PCa. Such capabilities would aid physicians and patients in treatment decisions, targeting biopsy, and planning focal therapy. A cohort of men with biopsy proven prostate cancer and pre-prostatectomy mpMRI were studied. PCa and benign ROIs (1524) were identified on mpMRI and histopathology with histopathology serving as the reference standard. Logistic regression models were created to differentiate PCa from benign tissues. The MRI images were registered to ensure correct overlay. The cancer models were applied to each image voxel within prostates to create probability maps of cancer and of high-grade cancer. Use of an optimum probability threshold quantified PCa volume for all lesions >0.1 cc. Accuracies were calculated using area under the curve (AUC) for the receiver operating characteristic (ROC). The PCa models utilized apparent diffusion coefficient (ADC), T2 weighted (T2W), dynamic contrast-enhanced MRI (DCE MRI) enhancement slope, and DCE MRI washout as the statistically significant MRI scans. Application of the PCa maps method provided total PCa volume and individual lesion volumes. The AUCs derived from lesion analysis were 0.91 for all PCa and 0.73 for high-grade PCa. At the optimum threshold, the PCa maps detected 135 / 150 (90%) histopathological lesions >0.1 cc. This study showed the feasibility of cancer risk maps, created from pre-prostatectomy, mpMR images validated with histopathology, to detect PCa lesions >0.1 cc. The method quantified the volume of cancer within the prostate. Method improvements were identified by determining root causes for over and underestimation of cancer volumes. The maps have the potential for improved non-invasive capability in quantitative detection, localization, volume estimation, and MRI characterization of PCa., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: Hepatic steatosis is a leading cause of cirrhosis and hepatocellular carcinoma and is highly prevalent in persons with HIV (PWH). However, most studies of hepatic steatosis diagnosis in PWH have focused on those at high risk. We determined the accuracy of vibration-controlled transient elastography (VCTE) with controlled attenuation parameter (CAP) in detecting mild or greater hepatic steatosis as compared with the noninvasive gold standard magnetic resonance spectroscopy (MRS) in PWH., Methods: Among 149 participants with and without HIV, we evaluated test characteristics of CAP and calculated serum indices Hepatic Steatosis Index (HSI) and STEATO-ELSA in identifying 3T MRS-measured hepatic steatosis (defined as a liver fat fraction ≥5%)., Results: Most participants were women and over half were African American. Median BMI was 27 kg/m 2 . Hepatic steatosis prevalence by MRS and CAP (cutoff 248 dB/m) was 36% and 47%, respectively. CAP had an AUROC of 0.82, and the at least 248 dB/m cutoff yielded a sensitivity, specificity, positive-predictive value, and negative-predictive value of 83%, 72%, 61%, and 88%, respectively. These test characteristics were not statistically different from the optimal cutoff of at least 252 dB/m. Higher waist circumference, greater visceral adipose tissue, heavy alcohol use, and VCTE scans flagged as having the probe positioned too low were associated with CAP and MRS discordance. Serum indices of hepatic steatosis had slightly worse performance characteristics than CAP., Conclusion: CAP may be an effective alternative to MRS for noninvasive hepatic steatosis assessment in PWH. The commonly used CAP cutoff of at least 248 dB/m to diagnose hepatic steatosis can be used in PWH., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Sugar intake, particularly fructose, is implicated as a factor contributing to insulin resistance via hepatic de novo lipogenesis (DNL). A nine-day fructose reduction trial, controlling for other dietary factors and weight, in children with obesity and metabolic syndrome, decreased DNL and mitigated cardiometabolic risk (CMR) biomarkers. Ceramides are bioactive sphingolipids whose dysregulated metabolism contribute to lipotoxicity, insulin resistance, and CMR. We evaluated the effect of fructose reduction on ceramides and correlations between changes observed and changes in traditional CMR biomarkers in this cohort. Analyses were completed on data from 43 participants. Mean weight decreased (-0.9 ± 1.1 kg). The majority of total and subspecies ceramide levels also decreased significantly, including dihydroceramides, deoxyceramides and ceramide-1-phoshates. Change in each primary ceramide species correlated negatively with composite insulin sensitivity index (CISI). Change in deoxyceramides positively correlated with change in DNL. These results suggest that ceramides decrease in response to dietary fructose restriction, negatively correlate with insulin sensitivity, and may represent an intermediary link between hepatic DNL, insulin resistance, and CMR.

In this study, the objective was to characterize the MR signatures of the various benign prostate tissues and to differentiate them from cancer. Data was from seventy prostate cancer patients who underwent multiparametric MRI (mpMRI) and subsequent prostatectomy. The scans included T2-weighted imaging (T2W), diffusion weighted imaging, dynamic contrast-enhanced MRI (DCE MRI), and MR spectroscopic imaging. Histopathology tissue information was translated to MRI images. The mpMRI parameters were characterized separately per zone and by tissue type. The tissues were ordered according to trends in tissue parameter means. The peripheral zone tissue order was cystic atrophy, high grade prostatic intraepithelial neoplasia (HGPIN), normal, atrophy, inflammation, and cancer. Decreasing values for tissue order were exhibited by ADC (1.8 10 -3  mm 2 /s to 1.2 10 -3  mm 2 /s) and T2W intensity (3447 to 2576). Increasing values occurred for DCE MRI peak (143% to 157%), DCE MRI slope (101%/min to 169%/min), fractional anisotropy (FA) (0.16 to 0.19), choline (7.2 to 12.2), and choline / citrate (0.3 to 0.9). The transition zone tissue order was cystic atrophy, mixed benign prostatic hyperplasia (BPH), normal, atrophy, inflammation, stroma, anterior fibromuscular stroma, and cancer. Decreasing values occurred for ADC (1.6 10 -3  mm 2 /s to 1.1 10 -3  mm 2 /s) and T2W intensity (2863 to 2001). Increasing values occurred for DCE MRI peak (143% to 150%), DCE MRI slope (101%/min to 137%/min), FA (0.18 to 0.25), choline (7.9 to 11.7), and choline / citrate (0.3 to 0.7). Logistic regression was used to create parameter model fits to differentiate cancer from benign prostate tissues. The fits achieved AUCs ≥0.91. This study quantified the mpMRI characteristics of benign prostate tissues and demonstrated the capability of mpMRI to discriminate among benign as well as cancer tissues, potentially aiding future discrimination of cancer from benign confounders., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The goal of the study was to establish early hyperpolarized (HP) 13 C MRI metabolic and perfusion changes that predict effective high-intensity focused ultrasound (HIFU) ablation and lead to improved adjuvant treatment of partially treated regions. To accomplish this a combined HP dual-agent ( 13 C pyruvate and 13 C urea) 13 C MRI/multiparametric 1 H MRI approach was used to measure prostate cancer metabolism and perfusion 3-4 h, 1 d, and 5 d after exposure to ablative and sub-lethal doses of HIFU within adenocarcinoma of mouse prostate tumors using a focused ultrasound applicator designed for murine studies. Pathologic and immunohistochemical analysis of the ablated tumor demonstrated fragmented, non-viable cells and vasculature consistent with coagulative necrosis, and a mixture of destroyed tissue and highly proliferative, poorly differentiated tumor cells in tumor tissues exposed to sub-lethal heat doses in the ablative margin. In ablated regions, the intensity of HP 13 C lactate or HP 13 C urea and dynamic contrast-enhanced (DCE) MRI area under the curve images were reduced to the level of background noise by 3-4 h after treatment with no recovery by the 5 d time point in either case. In the tissues that received sub-lethal heat dose, there was a significant 60% ± 12.4% drop in HP 13 C lactate production and a significant 30 ± 13.7% drop in urea perfusion 3-4 h after treatment, followed by recovery to baseline by 5 d after treatment. DCE MRI K trans showed a similar trend to HP 13 C urea, demonstrating a complete loss of perfusion with no recovery in the ablated region, while having a 40%-50% decrease 3-4 h after treatment followed by recovery to baseline values by 5 d in the margin region. The utility of the HP 13 C MR measures of perfusion and metabolism in optimizing focal HIFU, either alone or in combination with adjuvant therapy, deserves further testing in future studies., (© 2018 John Wiley & Sons, Ltd.)

Objective: To investigate the link between dietary sugar consumption and two separate pathogenetic mechanisms associated with metabolic syndrome: de novo lipogenesis (DNL) and nonenzymatic glycation., Design and Participants: We assessed changes in serum d-lactate (the detoxification end-product of methylglyoxal) concentration in response to 9 days of isocaloric fructose restriction in 20 children with obesity and metabolic syndrome, and examined correlations with changes in DNL, liver fat, insulin sensitivity, and other metrics of hepatic metabolism., Interventions: Nine days of dietary sugar restriction, with substitution of equal amounts of refined starch., Main Outcome Measures: On days 0 and 10, children had laboratory evaluation of d-lactate levels and other analytes, and underwent oral glucose tolerance testing, magnetic resonance spectroscopy to quantify fat depots, and 13C-acetate incorporation into triglyceride (TG) to measure DNL., Results: d-Lactate was associated with baseline liver fat fraction (P < 0.001) and visceral adipose tissue (P < 0.001) but not with subcutaneous adipose tissue. At baseline, d-lactate was positively correlated with DNL-area under the curve (AUC) (P = 0.003), liver fat fraction (P = 0.02), TG (P = 0.004), and TG/high-density lipoprotein ratio (P = 0.002). After 9 days of isocaloric fructose restriction, serum d-lactate levels reduced by 50% (P < 0.0001), and changes in d-lactate correlated with both changes in DNL-AUC and measures of insulin sensitivity., Conclusion: Baseline correlation of d-lactate with DNL and measures of insulin sensitivity and reduction in d-lactate after 9 days of isocaloric fructose restriction suggest that DNL and nonenzymatic glycation are functionally linked via intermediary glycolysis in the pathogenesis of metabolic syndrome and point to fructose as a key dietary substrate that drives both pathways., (Copyright © 2019 Endocrine Society.)

Agents targeting prostate-specific membrane antigen (PSMA) comprise a rapidly emerging class of radiopharmaceuticals for diagnostic imaging of prostate cancer. Unlike most other PSMA agents with a urea backbone, CTT1057 is based on a phosphoramidate scaffold that irreversibly binds to PSMA. We conducted a first-in-humans phase I study of CTT1057 in patients with localized and metastatic prostate cancer. Methods: Two patient cohorts were recruited. Cohort A patients had biopsy-proven localized prostate cancer preceding radical prostatectomy, and cohort B patients had metastatic castration-resistant prostate cancer. Cohort A patients were imaged at multiple time points after intravenous injection with 362 ± 8 MBq of CTT1057 to evaluate the kinetics of CTT1057 and estimate radiation dose profiles. Mean organ-absorbed doses and effective doses were calculated. CTT1057 uptake in the prostate gland and regional lymph nodes was correlated with pathology, PSMA staining, and the results of conventional imaging. In cohort B, patients were imaged 60-120 min after injection of CTT1057. PET images were assessed for overall image quality, and areas of abnormal uptake were contrasted with conventional imaging. Results: In cohort A ( n = 5), the average total effective dose was 0.023 mSv/MBq. The kidneys exhibited the highest absorbed dose, 0.067 mGy/MBq. The absorbed dose of the salivary glands was 0.015 mGy/MBq. For cohort B ( n = 15), CTT1057 PET detected 97 metastatic lesions, and 44 of 56 bone metastases detected on CTT1057 PET (78.5%) were also detectable on bone scanning. Eight of 32 lymph nodes positive on CTT1057 PET (25%) were enlarged by size criteria on CT. Conclusion: CTT1057 is a promising novel phosphoramidate PSMA-targeting 18 F-labeled PET radiopharmaceutical that demonstrates similar biodistribution to urea-based PSMA-targeted agents, with lower exposure to the kidneys and salivary glands. Metastatic lesions are detected with higher sensitivity on CTT1057 imaging than on conventional imaging. Further prospective studies with CTT1057 are warranted to elucidate its role in cancer imaging., (© 2019 by the Society of Nuclear Medicine and Molecular Imaging.)

Physiological properties of tumors can be measured both in vivo and noninvasively by diffusion-weighted imaging and dynamic contrast-enhanced magnetic resonance imaging. Although these techniques have been used for more than two decades to study tumor diffusion, perfusion, and/or permeability, the methods and studies on how to reduce measurement error and bias in the derived imaging metrics is still lacking in the literature. This is of paramount importance because the objective is to translate these quantitative imaging biomarkers (QIBs) into clinical trials, and ultimately in clinical practice. Standardization of the image acquisition using appropriate phantoms is the first step from a technical performance standpoint. The next step is to assess whether the imaging metrics have clinical value and meet the requirements for being a QIB as defined by the Radiological Society of North America's Quantitative Imaging Biomarkers Alliance (QIBA). The goal and mission of QIBA and the National Cancer Institute Quantitative Imaging Network (QIN) initiatives are to provide technical performance standards (QIBA profiles) and QIN tools for producing reliable QIBs for use in the clinical imaging community. Some of QIBA's development of quantitative diffusion-weighted imaging and dynamic contrast-enhanced QIB profiles has been hampered by the lack of literature for repeatability and reproducibility of the derived QIBs. The available research on this topic is scant and is not in sync with improvements or upgrades in MRI technology over the years. This review focuses on the need for QIBs in oncology applications and emphasizes the importance of the assessment of their reproducibility and repeatability. Level of Evidence: 5 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019;49:e101-e121., (© 2018 International Society for Magnetic Resonance in Medicine.)

Purpose: Radiation dose escalation for prostate cancer improves biochemical control but is limited by toxicity. Magnetic resonance spectroscopic imaging (MRSI) can define dominant intraprostatic lesions (DIL). This phase I study evaluated dose escalation to MRSI-defined DIL using high-dose-rate (HDR) brachytherapy., Material and Methods: Enrollment was closed early due to low accrual. Ten patients with prostate cancer (T2a-3b, Gleason 6-9, PSA < 20) underwent pre-treatment MRSI, and eight patients had one to three DIL identified. The eight enrolled patients received external beam radiation therapy to 45 Gy and HDR brachytherapy boost to the prostate of 19 Gy in 2 fractions. MRSI images were registered to planning CT images and DIL dose-escalated up to 150% of prescription dose while maintaining normal tissue constraints. The primary endpoint was genitourinary (GU) toxicity., Results: The median total DIL volume was 1.31 ml (range, 0.67-6.33 ml). Median DIL boost was 130% of prescription dose (range, 110-150%). Median urethra V 120 was 0.15 ml (range, 0-0.4 ml) and median rectum V 75 was 0.74 ml (range, 0.1-1.0 ml). Three patients had acute grade 2 GU toxicity, and two patients had late grade 2 GU toxicity. No patients had grade 2 or higher gastrointestinal toxicity, and no grade 3 or higher toxicities were noted. There were no biochemical failures with median follow-up of 4.9 years (range, 2-8.5 years)., Conclusions: Dose escalation to MRSI-defined DIL is feasible. Toxicity was low but incompletely assessed due to limited patients' enrollment., Competing Interests: The authors report no conflict of interest.

The purpose of this study was to characterize prostate cancer (PCa) based on multiparametric MR (mpMR) measures derived from MRI, diffusion, spectroscopy, and dynamic contrast-enhanced (DCE) MRI, and to validate mpMRI in detecting PCa and predicting PCa aggressiveness by correlating mpMRI findings with whole-mount histopathology. Seventy-eight men with untreated PCa received 3 T mpMR scans prior to radical prostatectomy. Cancerous regions were outlined, graded, and cancer amount estimated on whole-mount histology. Regions of interest were manually drawn on T 2 -weighted images based on histopathology. Logistic regression was used to identify optimal combinations of parameters for the peripheral zone and transition zone to separate: (i) benign from malignant tissues; (ii) Gleason score (GS) ≤3 + 3 disease from ≥GS3 + 4; and (iii) ≤ GS3 + 4 from ≥GS4 + 3 cancers. The performance of the models was assessed using repeated fourfold cross-validation. Additionally, the performance of the logistic regression models created under the assumption that one or more modality has not been acquired was evaluated. Logistic regression models yielded areas under the curve (AUCs) of 1.0 and 0.99 when separating benign from malignant tissues in the peripheral zone and the transition zone, respectively. Within the peripheral zone, combining choline, maximal enhancement slope, apparent diffusion coefficient (ADC), and citrate measures for separating ≤GS3 + 3 from ≥GS3 + 4 PCa yielded AUC = 0.84. Combining creatine, choline, and washout slope yielded AUC = 0.81 for discriminating ≤GS3 + 4 from ≥GS4 + 3 disease. Within the transition zone, combining washout slope, ADC, and creatine yielded AUC = 0.93 for discriminating ≤GS3 + 3 and ≥GS3 + 4 cancers. When separating ≤GS3 + 4 from ≥GS4 + 3 PCa, combining choline and washout slope yielded AUC = 0.92. MpMRI provides excellent separation between benign tissues and PCa, and across PCa tissues of different aggressiveness. The final models prominently feature spectroscopy and DCE-derived metrics, underlining their value within a comprehensive mpMRI examination., (Copyright © 2017 John Wiley & Sons, Ltd.)

Background & Aims: Consumption of sugar is associated with obesity, type 2 diabetes mellitus, nonalcoholic fatty liver disease, and cardiovascular disease. The conversion of fructose to fat in liver (de novo lipogenesis [DNL]) may be a modifiable pathogenetic pathway. We determined the effect of 9 days of isocaloric fructose restriction on DNL, liver fat, visceral fat (VAT), subcutaneous fat, and insulin kinetics in obese Latino and African American children with habitual high sugar consumption (fructose intake >50 g/d)., Methods: Children (9-18 years old; n = 41) had all meals provided for 9 days with the same energy and macronutrient composition as their standard diet, but with starch substituted for sugar, yielding a final fructose content of 4% of total kilocalories. Metabolic assessments were performed before and after fructose restriction. Liver fat, VAT, and subcutaneous fat were determined by magnetic resonance spectroscopy and imaging. The fractional DNL area under the curve value was measured using stable isotope tracers and gas chromatography/mass spectrometry. Insulin kinetics were calculated from oral glucose tolerance tests. Paired analyses compared change from day 0 to day 10 within each child., Results: Compared with baseline, on day 10, liver fat decreased from a median of 7.2% (interquartile range [IQR], 2.5%-14.8%) to 3.8% (IQR, 1.7%-15.5%) (P < .001) and VAT decreased from 123 cm 3 (IQR, 85-145 cm 3 ) to 110 cm 3 (IQR, 84-134 cm 3 ) (P < .001). The DNL area under the curve decreased from 68% (IQR, 46%-83%) to 26% (IQR, 16%-37%) (P < .001). Insulin kinetics improved (P < .001). These changes occurred irrespective of baseline liver fat., Conclusions: Short-term (9 days) isocaloric fructose restriction decreased liver fat, VAT, and DNL, and improved insulin kinetics in children with obesity. These findings support efforts to reduce sugar consumption. ClinicalTrials.gov Number: NCT01200043., (Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.)

The purpose of this study was to determine whether 5α-reductase inhibitors (5-ARIs) affect the discrimination between low-grade prostate cancer and benign tissues on multiparametric MRI (mpMRI). Twenty men with biopsy-proven Gleason 3 + 3 prostate cancer and 3 T mpMRI were studied. Ten patients (Tx) had been receiving 5-ARIs for at least a year at scan time. Ten untreated patients (Un) were matched to the treated cohort. For each subject two regions of interest representing cancerous and benign tissues were drawn within the peripheral zone of each prostate, MR measures evaluated, and cancer contrast versus benign (contrast = (MR Tumor  - MR Healthy )/MR Healthy ) calculated. Decreased cancer contrast was noted on T 2 -weighted images: 0.4 (Un) versus 0.3 (Tx). However, for functional MR measures, a better separation of cancerous and benign tissues was observed in the treated group. Cancer contrast on high-b diffusion-weighted imaging (DWI) was 0.61 (Un) versus 0.99 (Tx). Logistic regression analysis yielded higher AUC (area under the curve) values for distinguishing cancerous from benign regions in treated subjects on high-b DWI (0.71 (Un), 0.94 (Tx)), maximal enhancement slope (0.95 (Un), 1 (Tx)), peak enhancement (0.84 (Un), 0.93 (Tx)), washout slope (0.78 (Un), 0.99 (Tx)), K trans (0.9 (Un), 1 (Tx)), and combined measures (0.86 (Un), 0.99 (Tx)). Coefficients of variation for MR measures were lower in benign and cancerous tissues in the treated group compared with the untreated group. This study's results suggest an increase in homogeneity of benign and malignant peripheral zone prostatic tissues with 5-ARI exposure, observed as reduced variability of MR measures after treatment. Cancer discrimination was lower with T 2 -weighted imaging, but was higher with functional MR measures in a 5-ARI-treated cohort compared with controls., (Copyright © 2017 John Wiley & Sons, Ltd.)

Hepatic steatosis (HS) is common in individuals with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections, but the independent contributions of HCV and HIV to HS are unclear. Magnetic resonance imaging and spectroscopy were used to measure visceral adipose tissue (VAT) and liver fat fraction (LFF) (total lipids/[total lipids + water]) in 356 adults: 57 with HCV monoinfection, 70 with HIV/HCV coinfection, 122 with HIV monoinfection, and 107 with neither infection. Participants who were infected with HCV genotype 3 were excluded because of the genotype's reported steatogenic effects. For prevalence estimates, HS was defined as LFF ≥ 0.05. We estimated the association of HIV and HCV status with LFF using multivariable linear regression, adjusting for demographics, lifestyle, and metabolic factors including the homeostasis model assessment estimate of insulin resistance (HOMA-IR) and liver fibrosis defined using the aspartate aminotransferase-to-platelet ratio index (APRI). The prevalence of HS was highest in the uninfected (33%) and HIV-monoinfected (28%), followed by the HCV-monoinfected (19%) and HIV/HCV-coinfected (11%) (P = 0.003 across groups). Compared with uninfected participants-and after adjusting for demographics, lifestyle, and metabolic factors-HIV monoinfection, HCV monoinfection, and HIV/HCV coinfection were associated with 19% (95% confidence interval [CI], -39% to 6%), 38% (95% CI, -55% to -12%), and 42% (95% CI, -59% to -18%) lower LFF, respectively. HCV monoinfection and HIV/HCV coinfection remained strongly associated with lower LFF after further adjusting for APRI, and results were unchanged after excluding subjects with suspected cirrhosis. Among the entire cohort, Hispanic ethnicity, male sex, VAT, and HOMA-IR were independently associated with greater LFF., Conclusion: Contrary to expectations, HIV/HCV-coinfected and HCV-monoinfected adults had significantly less liver fat than uninfected adults, even after adjusting for demographics, lifestyle, metabolic factors, and hepatic fibrosis. Our findings suggest that non-genotype 3 HCV infection may be protective against HS. The mechanisms by which this occurs and the impact of HCV treatment on HS requires further investigation. (Hepatology 2017;65:853-863)., (© 2016 by the American Association for the Study of Liver Diseases.)

Purpose To investigate the initial clinical value of fluorine 18 ( 18 F) fluorocholine (FCH) dynamic positron emission tomography (PET)/magnetic resonance (MR) imaging by comparing its parameters with clinical-pathologic findings in patients with newly diagnosed intermediate- to high-risk prostate cancer (PCa) who plan to undergo radical prostatectomy. Materials and Methods The institutional review board approved the study protocol, and informed written consent was obtained from all subjects for this HIPAA-compliant study. Twelve men (mean age ± standard deviation, 61.7 years ± 8.4; range, 46-74 years) with untreated intermediate- to high-risk PCa characterized according to Cancer of the Prostate Risk Assessment (CAPRA) underwent preoperative FCH dynamic PET/MR imaging followed by radical prostatectomy between April and November 2015. PET/MR imaging parameters including average and maximum K1 (delivery rate constant) and standardized uptake values (SUVs) and Prostate Imaging Reporting and Data System (PI-RADS) version 2 scores were measured and compared with clinical-pathologic characteristics. For statistical analysis, the Spearman rank correlation and Mann-Whitney U tests were performed. Results Of the PET parameters, maximum SUV of primary tumors showed significant correlations with several clinical-pathologic parameters including serum prostate-specific antigen level (ρ = 0.71, P = .01), pathologic stage (ρ = 0.59, P = .043), and postsurgical CAPRA score (ρ = 0.72, P = .008). The overall PI-RADS score showed significant correlations with pathologic tumor volume (ρ = 0.81, P < .001), percentage of tumor cells with Gleason scores greater than 3 (ρ = 0.59, P = .02), and postsurgical CAPRA score (ρ = 0.58, P = .046). The high-risk postsurgical CAPRA score patient group had a significantly higher maximum SUV than did the intermediate-risk group. Combined PET and MR imaging showed improved sensitivity (88%) for prediction of pathologic extraprostatic extension compared with that with MR imaging (50%) and PET (75%) performed separately. Conclusion Maximum SUVs and PI-RADS scores from FCH PET/MR imaging show good correlation with clinical-pathologic characteristics, such as postsurgical CAPRA score, which are related to prognosis in patients with newly diagnosed intermediate- to high-risk PCa. © RSNA, 2016 Online supplemental material is available for this article.

Background: Hepatic steatosis is increasing worldwide. Whether HIV and its associated metabolic perturbations exacerbate steatosis is unclear. Sex differences in adipose tissue distribution may also affect steatosis risk. We examined the contribution of HIV and sex to steatosis., Methods: Using MRI and spectroscopy, visceral adipose tissue (VAT) and liver fat fraction (LFF) were measured in 121 HIV-infected and 107 uninfected men and women without viral hepatitis. Differences in LFF by HIV status and sex were evaluated using multivariable linear regression, adjusting for demographic, lifestyle, VAT, homeostasis model assessment-estimated insulin resistance, and HIV-related factors., Results: HIV-infected women had lower LFF than uninfected women (demographic-adjusted mean: 1.9 vs. 3.1%; P = 0.028); LFF was similar in HIV-infected and uninfected men (4.6 vs. 4.1%; P = 0.78). HIV-infected and uninfected women had less VAT than men (median: 139 and 161 vs. 201 cm and 188 cm, respectively). After adjustment, HIV-infected women had 34% [95% confidence interval (CI): -54%, -5.5%] lower LFF than uninfected women, whereas there was little difference in men (-5.5%; 95% CI: -26%, 21%). Among HIV-infected persons, greater VAT and homeostasis model assessment-estimated insulin resistance were associated with greater LFF. HIV-related factors (CD4 cell count, HIV RNA level, or antiretroviral therapy use) had little association with LFF. Although HIV-infected men had 81% (95% CI: 32%, 148%) greater LFF than HIV-infected women, the association was attenuated after multivariable adjustment (25%; 95% CI: -9.1%, 73%)., Conclusion: Contrary to expectation, HIV infection is not associated with greater steatosis compared with uninfected adults. It is possible that less fat is stored in the liver to maintain subcutaneous fat (which is reduced in HIV) and the effect is magnified in HIV-infected women, who also have less VAT., Competing Interests: Potential competing interests: The authors do not have any commercial or other associations that might pose a conflict of interest.

Background and Aims: Dietary fructose may play a role in the pathogenesis of metabolic syndrome (MetS). In a recently published study of obese children with MetS, we showed that isocaloric fructose restriction reduced fasting triglyceride (TG) and LDL-cholesterol (LDL-C). In these ancillary analyses, we tested the hypothesis that these effects were also accompanied by improved quantitative and qualitative changes in LDL and HDL subclasses and their apolipoproteins; as well as change in VLDL, particularly apoC-III., Methods: Obese children with MetS (n = 37) consumed a diet that matched self-reported macronutrient composition for nine days, with the exception that dietary fructose was reduced from 11.7 ± 4.0% to 3.8 ± 0.5% of daily calories and substituted with glucose (in starch). Participants underwent fasting biochemical analyses on Days 0 and 10. HDL and LDL subclasses were analyzed using the Lipoprint HDL and LDL subfraction analysis systems from Quantimetrix., Results: Significant reductions in apoB (78 ± 24 vs. 66 ± 24 mg/dl) apoC-III (8.7 ± 3.5 vs. 6.5 ± 2.6 mg/dl) and apoE (4.6 ± 2.3 vs. 3.6 ± 1.1 mg/dl), all p < 0.001) were observed. LDL size increased by 0.87 Å (p = 0.008). Small dense LDL was present in 25% of our cohort and decreased by 68% (p = 0.04). Small HDL decreased by 2.7% (p < 0.001) and large HDL increased by 2.4% (p = 0.04). The TG/HDL-C ratio decreased from 3.1 ± 2.5 to 2.4 ± 1.4 (p = 0.02). These changes in fasting lipid profiles correlated with changes in insulin sensitivity., Conclusions: Isocaloric fructose restriction for 9 days improved lipoprotein markers of CVD risk in children with obesity and MetS. The most dramatic reduction was seen for apoC-III, which has been associated with atherogenic hypertriglyceridemia., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

The use of multiparametric MRI scans for the evaluation of men with prostate cancer has increased dramatically and is likely to continue expanding as new developments come to practice. However, it has not yet gained the same level of acceptance of other imaging tests. Partly, this is because of the use of suboptimal protocols, lack of standardization, and inadequate patient preparation. In this manuscript, we describe several practical aspects of prostate MRI that may facilitate the implementation of new prostate imaging programs or the expansion of existing ones.

Objective: Dietary fructose is implicated in metabolic syndrome, but intervention studies are confounded by positive caloric balance, changes in adiposity, or artifactually high amounts. This study determined whether isocaloric substitution of starch for sugar would improve metabolic parameters in Latino (n = 27) and African-American (n = 16) children with obesity and metabolic syndrome., Methods: Participants consumed a diet for 9 days to deliver comparable percentages of protein, fat, and carbohydrate as their self-reported diet; however, dietary sugar was reduced from 28% to 10% and substituted with starch. Participants recorded daily weights, with calories adjusted for weight maintenance. Participants underwent dual-energy X-ray absorptiometry and oral glucose tolerance testing on Days 0 and 10. Biochemical analyses were controlled for weight change by repeated measures ANCOVA., Results: Reductions in diastolic blood pressure (-5 mmHg; P = 0.002), lactate (-0.3 mmol/L; P < 0.001), triglyceride, and LDL-cholesterol (-46% and -0.3 mmol/L; P < 0.001) were noted. Glucose tolerance and hyperinsulinemia improved (P < 0.001). Weight reduced by 0.9 ± 0.2 kg (P < 0.001) and fat-free mass by 0.6 kg (P = 0.04). Post hoc sensitivity analysis demonstrates that results in the subcohort that did not lose weight (n = 10) were directionally consistent., Conclusions: Isocaloric fructose restriction improved surrogate metabolic parameters in children with obesity and metabolic syndrome irrespective of weight change., (© 2015 The Obesity Society.)

Objective: The goal of this study was to compare the perceived quality of 3-T axial T2-weighted high-resolution 2D and high-resolution 3D fast spin-echo (FSE) endorectal MR images of the prostate., Materials and Methods: Six radiologists independently reviewed paired 3-T axial T2-weighted high-resolution 2D and 3D FSE endorectal MR images of the prostates of 85 men in two sessions. In the first session (n = 85), each reader selected his or her preferred images; in the second session (n = 28), they determined their confidence in tumor identification and compared the depiction of the prostatic anatomy, tumor conspicuity, and subjective intrinsic image quality of images. A meta-analysis using a random-effects model, logistic regression, and the paired Wilcoxon rank-sum test were used for statistical analyses., Results: Three readers preferred the 2D acquisition (67-89%), and the other three preferred the 3D images (70-80%). The option for one of the techniques was not associated with any of the predictor variables. The 2D FSE images were significantly sharper than 3D FSE (p < 0.001) and significantly more likely to exhibit other (nonmotion) artifacts (p = 0.002). No other statistically significant differences were found., Conclusion: Our results suggest that there are strong individual preferences for the 2D or 3D FSE MR images, but there was a wide variability among radiologists. There were differences in image quality (image sharpness and presence of artifacts not related to motion) but not in the sequences' ability to delineate the glandular anatomy and depict a cancerous tumor.

Context: Consumption of high-fructose diets promotes hepatic fatty acid synthesis (de novo lipogenesis [DNL]) and an atherogenic lipid profile. It is unclear whether these effects occur independent of positive energy balance and weight gain., Objectives: We compared the effects of a high-fructose, (25% of energy content) weight-maintaining diet to those of an isocaloric diet with the same macronutrient distribution but in which complex carbohydrate (CCHO) was substituted for fructose., Design, Setting, and Participants: Eight healthy men were studied as inpatients for consecutive 9-day periods. Stable isotope tracers were used to measure fractional hepatic DNL and endogenous glucose production (EGP) and its suppression during a euglycemic-hyperinsulinemic clamp. Liver fat was measured by magnetic resonance spectroscopy., Results: Weight remained stable. Regardless of the order in which the diets were fed, the high-fructose diet was associated with both higher DNL (average, 18.6 ± 1.4% vs 11.0 ± 1.4% for CCHO; P = .001) and higher liver fat (median, +137% of CCHO; P = .016) in all participants. Fasting EGP and insulin-mediated glucose disposal did not differ significantly, but EGP during hyperinsulinemia was greater (0.60 ± 0.07 vs 0.46 ± 0.06 mg/kg/min; P = .013) with the high-fructose diet, suggesting blunted suppression of EGP., Conclusion: Short-term high-fructose intake was associated with increased DNL and liver fat in healthy men fed weight-maintaining diets.

Purpose: To determine the ability of multiparametric MR imaging to predict disease progression in patients with prostate cancer managed by active surveillance., Methods: Sixty-four men with biopsy-proven prostate cancer managed by active surveillance were included in this HIPPA compliant, IRB approved study. We reviewed baseline MR imaging scans for the presence of a suspicious findings on T2-weighted imaging, MR spectroscopic imaging (MRSI), and diffusion-weighted MR imaging (DWI). The Gleason grades at subsequent biopsy were recorded. A Cox proportional hazard model was used to determine the predictive value of MR imaging for Gleason grades, and the model performance was described using Harrell's C concordance statistic and 95% confidence intervals (CIs)., Results: The Cox model that incorporated T2-weighted MR imaging, DWI, and MRSI showed that only T2-weighted MR imaging and DWI are independent predictors of biopsy upgrade (T2; HR = 2.46; 95% CI 1.36-4.46; P = 0.003-diffusion; HR = 2.76; 95% CI 1.13-6.71; P = 0.03; c statistic = 67.7%; 95% CI 61.1-74.3). There was an increasing rate of Gleason score upgrade with a greater number of concordant findings on multiple MR sequences (HR = 2.49; 95% CI 1.72-3.62; P < 0.001)., Conclusions: Abnormal results on multiparametric prostate MRI confer an increased risk for Gleason score upgrade at subsequent biopsy in men with localized prostate cancer managed by active surveillance. These results may be of help in appropriately selecting candidates for active surveillance.

Objective: To quantify bone structure and perfusion parameters in regions of bone marrow edema pattern (BMEP), non-edematous bone marrow (NBM), and pannus tissue areas in the wrists of patients with rheumatoid arthritis (RA) using 3-Tesla (3T) magnetic resonance imaging (MRI), and high resolution peripheral quantitative computed tomography (HR-pQCT)., Methods: Sixteen subjects fulfilling American College of Rheumatology classification were imaged using a HR-pQCT system and a 3T MRI scanner with an 8-channel wrist coil. Coronal T2-weighted and dynamic contrast-enhanced (DCE-MRI) images were acquired. BMEP and pannus tissue areas were segmented semiautomatically in T2-weighted images. NBM areas were placed at a similar distance from the joint space as BMEP regions. MR and HR-pQCT images were registered, and bone variables were calculated within the BMEP and NBM regions. Perfusion parameters in BMEP, pannus tissue, and NBM regions were calculated based on the signal-time curve obtained from DCE-MRI., Results: Eighteen BMEP areas were segmented, 15 of them presented proximal to pannus-filled erosions. Significant increases in bone density and trabecular thickness and number were observed in all BMEP regions compared to NMB (p < 0.05). Significantly elevated perfusion measures were observed in both BMEP and pannus tissue regions compared to NBM (p < 0.05)., Conclusion: BMEP regions showed significantly increased bone density and structures as well as perfusion measures, suggesting bone remodeling and active inflammation. Combining MRI and HR-pQCT provides a powerful multimodality approach for understanding BMEP and erosions, and for potentially identifying novel imaging markers for disease progression in RA.

Purpose: To evaluate a semiautomatic software-based method of registering in vivo prostate MR images to digital histopathology images using two approaches: (i) in which the prostates were molded to simulate distortion due to the endorectal imaging coil before fixation, and (ii) in which the prostates were not molded., Materials and Methods: T2-weighted MR images and digitized whole-mount histopathology images were acquired for 26 patients with biopsy-confirmed prostate cancer who underwent radical prostatectomy. Ten excised prostates were molded before fixation. A semiautomatic method was used to align MR images to histopathology. Percent overlap between MR and histopathology images, as well as distances between corresponding anatomical landmarks were calculated and used to evaluate the registration technique for molded and unmolded cases., Results: The software successfully morphed histology-based prostate images into corresponding MR images. Percent overlap improved from 80.4 ± 5.8% before morphing to 99.7 ± 0.62% post morphing. Molded prostates had a smaller distance between landmarks (1.91 ± 0.75 mm) versus unmolded (2.34 ± 0.68 mm), P < 0.08., Conclusion: Molding a prostate before fixation provided a better alignment of internal structures within the prostate, but this did not reach statistical significance. Software-based morphing allowed for nearly complete overlap between the pathology slides and the MR images., (Copyright © 2013 Wiley Periodicals, Inc.)

Purpose: To investigate the role of endorectal MR imaging and MR spectroscopic imaging in defining the contour of treatable intraprostatic tumor foci in prostate cancer, since targeted therapy requires accurate target volume definition., Materials and Methods: We retrospectively identified 20 patients with prostate cancer who underwent endorectal MR imaging and MR spectroscopic imaging prior to radical prostatectomy and subsequent creation of detailed histopathological tumor maps from whole-mount step sections. Two experienced radiologists independently reviewed all MR images and electronically contoured all suspected treatable (≥0.5 cm(3)) tumor foci. Deformable co-registration in MATLAB was used to calculate the margin of error between imaging and histopathological contours at both capsular and non-capsular surfaces and the treatment margin required to ensure at least 95% tumor coverage., Results: Histopathology showed 17 treatable tumor foci in 16 patients, of which 8 were correctly identified by both readers and an additional 2 were correctly identified by reader 2. For all correctly identified lesions, both readers accurately identified that tumor contacted the prostatic capsule, with no error in contour identification. On the non-capsular border, the median distance between the imaging and histopathological contour was 1.4mm (range, 0-12). Expanding the contour by 5mm at the non-capsular margin included 95% of tumor volume not initially covered within the MR contour., Conclusions: Endorectal MR imaging and MR spectroscopic imaging can be used to accurately contour treatable intraprostatic tumor foci; adequate tumor coverage is achieved by expanding the treatment contour at the non-capsular margin by 5mm., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To determine if the concordance of magnetic resonance (MR) imaging and MR spectroscopic data with histologic measures of steatosis is affected by histologic magnification level, tissue heterogeneity, or assessment of tissue area versus that of hepatocytes., Materials and Methods: This study was institutional review board approved and HIPAA compliant. Written informed consent was obtained. In- and out-of-phase MR imaging and MR spectroscopic measures of steatosis were compared in 33 patients with nonalcoholic fatty liver disease and in 15 healthy volunteers. Concordance of MR imaging and MR spectroscopic data with histologic findings was assessed for (a) histologic examination at standard (×40 and ×100) versus high magnification (×200 and ×400), (b) heterogeneity and homogeneity of livers, and (c) percentage of tissue and hepatocytes that contained lipids. Evaluations included linear regression and Fisher exact tests., Results: In- and out-of-phase MR imaging and MR spectroscopic data were well correlated (R2=0.93) and generally concordant with histologic measures. Patients in whom MR fat fractions were higher than expected compared with steatosis grades at standard magnification histologic examination were upgraded significantly more often when high magnification was used than were the remaining patients (100% [10 of 10] vs 47% [7 of 15], P<.01). MR imaging and MR spectroscopic data of homogeneous livers were significantly more likely than those of heterogeneous livers to be concordant with steatosis grades when high magnification was used (81% [13 of 16] vs 47% [8 of 17], P<.05). For all patients, percentage of fat in tissue was lower than that in hepatocytes, which affected individual patients, but not the overall correlation., Conclusion: MR imaging and MR spectroscopic data were generally concordant with histologic measures of steatosis. Discordance between them may reflect differences in magnification at histologic examination and in liver heterogeneity., (© RSNA, 2012.)

Objective: The purpose of this article is to develop and validate a chemical-shift imaging-derived color mapping system for evaluation of liver steatosis., Materials and Methods: Opposed phase MRI was evaluated for 85 subjects (51 with presumed nonalcoholic fatty liver disease and 34 healthy volunteers). Liver signal intensity loss was compared with histologic analysis for 52 subjects, assuming grade 0 steatosis for healthy volunteers, to determine signal-intensity-loss threshold points differentiating steatosis grades and subsequent Spearman correlation. Color scale grading was then applied for 78 subjects. Interpretation of color maps for steatosis severity and heterogeneity was performed by three readers. Analyses of agreement among readers and of color map steatosis grade with biopsy were performed using weighted kappa values., Results: The numbers of subjects with steatosis grades 0, 1, 2, and 3 were 41, 12, 13, and 19, respectively. A correlation of 0.90 was obtained using selected threshold values of 5.9% or less, 6-26.1%, 26.2-36.8%, and greater than 36.8% for steatosis grades 0, 1, 2, and 3, respectively. Interobserver agreement for color map grading of steatosis was excellent (κ = 0.93-0.94). Color map interpretation for all readers also showed excellent agreement with histologic findings for whole liver (κ = 0.82-0.86) and estimated biopsy site location (κ = 0.81-0.86; anterior region of right lobe). Heterogeneous steatosis on color maps was identified in 56-60% of subjects with nonalcoholic fatty liver disease and in 7% of healthy volunteers and was associated with greater disagreement between color map and histology grading (61-74%) compared with the whole group (37-40%)., Conclusion: MRI-derived color map estimation of liver steatosis grade appears to be reproducible and accurate.

Purpose: To compare liver ADC obtained with breathhold and free-breathing diffusion weighted imaging (DWI) in healthy volunteers and patients with liver disease., Materials and Methods: Twenty-eight subjects, 12 healthy volunteers and 16 patients (9 NAFLD, 7 chronic active HCV), underwent breathhold (BH) and free-breathing (FB) DWI MRI at 1.5 Tesla. Pearson's correlation coefficient was used to determine correlation while paired t-tests assessed differences between BH and FB ADC. Estimated bias was calculated using the Bland-Altman method., Results: Liver ADC (×10(-3) mm(2) /s) was lower on BH for all groups (mean difference 0.36 ± 0.20; P < 0.01). ADC was higher in healthy volunteers (BH 1.80 ± 0.18; FB 2.24 ± 0.20) compared with NAFLD patients (BH 1.43 ± 0.27; FB 1.78 ± 0.28) (P < 0.001) and HCV patients (BH 1.63 ± 0.191; FB 1.88 ± 0.12). Overall correlation between BH and FB ADC was (r = 0.75), greatest in NAFLD (r = 0.90) compared with the correlation in HCV (r = 0.24) and healthy subjects (r = 0.34). Bland-Altman plots did not show agreement in mean absolute difference and estimated bias between subjects., Conclusion: Correlation between BH and FB liver ADC is moderate indicating that BH and FB should not be used interchangeably. Additionally, the lower ADC values in BH versus FB should be accounted for when comparing different liver DWI studies., (Copyright © 2011 Wiley-Liss, Inc.)

Purpose: To develop imaging techniques that provide quantitative characterization of bone marrow edema pattern (BME) in wrist joints of patients with rheumatoid arthritis (RA), including volume, signal intensity changes, and perfusion properties., Materials and Methods: Fourteen RA patients and three controls were scanned using 3 Tesla MR. BME was semi-automatically segmented in water images obtained from iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) sequences. BME perfusion parameters (enhancement and slope) were evaluated using three-dimensional (3D) dynamic enhanced MRI (DCE-MRI). Experimental reproducibility, inter- and intra-observer reproducibility of BME quantification were evaluated using root mean square coefficients of variation (RMS-CV) and intraclass correlation (ICC)., Results: The RMS-CV for BME volume quantification with repeated scans were 6.9%. The inter-observer ICC was 0.993 and RMS CV was 5.2%. The intra-observer ICC was 0.998 and RMS CV was 2.3%. Both maximum enhancement and slope during DCE-MRI were significantly higher in BME than in normal bone marrow (P < 0.001). No significant correlation was found between BME quantification and clinical evaluations., Conclusion: A highly reproducible semi-automatic method for quantifying BME lesion burden in RA was developed, which may enhance our capability of predicting disease progression and monitoring treatment response., (Copyright © 2011 Wiley Periodicals, Inc.)

Objective: •To evaluate the effects of dutasteride on treatment-naïve prostate cancer in men using serial magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging (MRSI) in this pilot study., Patients and Methods: •This investigator-initiated prospective single-arm study was approved by the institutional committee on human research ethics board. •The target accrual was 10 patients. Newly diagnosed prostate cancer patients with low risk disease either with symptomatic benign prostatic hypertrophy or deemed to require pre-brachytherapy androgen suppression therapy were eligible. In the latter group, dutasteride was used to achieve cytoreduction. •All patients received 6 months of dutasteride 3.5 mg daily and underwent baseline blood work, health-related quality of life indices and MRI/MRSI, which were repeated at 1, 3 and 6 months. •MRSI spectra were examined and scored as healthy or cancerous. The change in cancerous volumes over time was evaluated., Results: •Of the 10 patients enrolled, nine patients completed the entire study. One patient withdrew after 3 months because of drug-related toxicity. •Because a significant decrease in citrate and polyamines on MRSI spectra was noted at 1 month compared with baseline, healthy tissue appeared to be more like cancer and thus created a false impression that the cancer had grown after 1 month. To reduce this bias, comparisons were made between the 1-month and 6-month scans. •The median MR cancer volumes at 6 months and 3 months were 100% and 101% of the 1-month value, respectively. Three of the nine patients had a 30-45% decrease in cancer volume at 6 months relative to 1-month measures. Of the others, two had no change in cancer volume and four had an increase (range 65-167% of the 1-month value). •The median cancer volume (range) at baseline was only 0.5 (0.1-5.6) mL., Conclusions: •The inclusion of only men with low volume disease may have limited our ability to accurately assess response rates after dutasteride due to the background effects on normal prostate metabolism. Despite this, one-third of patients had a 30-45% reduction in cancer volume at 6 months. •Future studies including men with larger volume disease may enable estimates of response rates to be made more accurately., (© 2011 THE AUTHORS. BJU INTERNATIONAL © 2011 BJU INTERNATIONAL.)

Background: Hepatic steatosis is common in persons with HIV and hepatitis C virus (HCV); yet biopsy measurement of steatosis is prone to sampling error. We compared magnetic resonance spectroscopy (MRS) measurement of steatosis to histology in HIV/HCV-coinfected patients and explored the associated adipose tissue and metabolic factors., Methods: Cross-sectional analysis of 42 HIV/HCV-coinfected men and women. Logistic regression analysis identified factors (MRI-measured visceral adipose tissue and abdominal subcutaneous adipose tissue and Homeostasis Model Assessment-estimated insulin resistance) associated with histologic steatosis (≥ 5% of hepatocytes with fat) and MRS steatosis (≥ 5% of hepatic fat)., Results: MRS steatosis was strongly associated with histologic steatosis, when measured continuously (odds ratio: 10.2 per doubling of MRS-measured hepatic fat; 95% confidence interval: 2.9 to 69.3) and dichotomously (Kappa coefficient = 0.52; P = 0.0007). Four of the 10 with MRS-measured steatosis did not have histologic steatosis; 3 of 9 with histologic steatosis did not have MRS-measured steatosis (67% sensitivity; 88% specificity). Associations of visceral adipose tissue and abdominal subcutaneous adipose tissue were associated with both histologic and MRS-measured steatosis. Insulin resistance was also associated with both., Conclusions: When compared with histology, MRS was similarly associated with adipose tissue and metabolic factors. MRS is a useful noninvasive alternative to biopsy in HIV/HCV coinfection.

Purpose: To develop and validate a post-processing correction algorithm to remove the effect of the inhomogeneous reception profile of the endorectal coil on MR spectroscopic imaging (MRSI) data., Materials and Methods: A post-processing algorithm to correct for the endorectal coil reception effects on MRSI data was developed based upon theoretical modeling of the endorectal coil reception profile and of the spatial saturation pulse profiles. This algorithm was evaluated on three-dimensional (3D) MRSI data acquired at 3T from a uniform phantom and from 18 patients with known or suspected prostate cancer., Results: For the phantom data, the coefficient of variation of metabolite peak areas decreased 16% to 46% and the peak area distributions became more Gaussian with correction, as demonstrated by higher Q-Q plot linear correlations (R(2) = 0.98 +/- 0.007 vs. R(2) = 0.89 +/- 0.066). Across the 18 patients, the mean coefficient of variation for suppressed water decreased significantly, from 0.95 +/- 0.18, to 0.66 +/- 0.11, (P < 10(-6), paired t-test) and the linear correlations of the Q-Q plots for the suppressed water increased from R(2) = 0.91 to R(2) = 0.95 (P = 0.0083, paired t-test) with correction., Conclusion: An algorithm for reducing the effect of the inhomogeneous reception profile in endorectal coil acquired 3D MRSI prostate data was demonstrated, illustrating increased homogeneity and more Gaussian peak area distributions.

Purpose: To develop a post-processing, respiratory-motion correction algorithm for magnetic resonance spectroscopy (MRS) of the liver and to determine the incidence and impact of respiratory motion in liver MRS., Materials and Methods: One hundred thirty-two subjects (27 healthy, 31 with nonalcoholic fatty liver disease and 74 HIV-infected with or without hepatitis C) were scanned with free breathing MRS at 1.5 T. Two spectral time series were acquired on an 8-ml single voxel using TR/TE=2500 ms/30 ms and (1) water suppression, 128 acquisitions, and (2) no water suppression, 8 acquisitions. Individual spectra were phased and frequency aligned to correct for intrahepatic motion. Next, water peaks more than 50% different from the median water peak area were identified and removed, and remaining spectra averaged to correct for presumed extrahepatic motion. Total CH(2)+CH(3) lipids to unsuppressed water ratios were compared before and after corrections., Results: Intrahepatic-motion correction increased the signal to noise ratio (S/N) in all cases (median=11-fold). Presumed extrahepatic motion was present in 41% (54/132) of the subjects. Its correction altered the lipids/water magnitude (magnitude change: median=2.6%, maximum=290%, and was >5% in 25% of these subjects). The incidence and effect of respiratory motion on lipids/water magnitude were similar among the three groups., Conclusion: Respiratory-motion correction of free breathing liver MRS greatly increased the S/N and, in a significant number of subjects, changed the lipids/water ratios, relevant for monitoring subjects.

Purpose: To compare peak enhancement (PE), determined from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and the magnetic resonance (MR) directionally-averaged apparent diffusion coefficient () in glandular versus stromal prostatic tissues and, with this comparison, to infer if the hypothesis that gadolinium-DTPA (Gd-DTPA) does not enter healthy glands or ducts is plausible., Materials and Methods: MRI, MR spectroscopic imaging, DCE MRI and MR diffusion were evaluated in 17 untreated subjects with suspected or proven prostate cancer. PE and were compared in glandular-ductal tissues [normal peripheral zone and glandular benign prostatic hyperplasia (BPH)] and stromal-low ductal tissues (central gland/mixed BPH and stromal BPH)., Results: The glandular-ductal tissues had lower PE [125+/-6.4 (% baseline)] and higher [1.57+/-0.15 (s/10(-3) mm2)] than the stromal-low ductal tissues [PE=132+/-5.5 (% baseline) (P< .0008), =1.18+/-0.20 (s/10(-3) mm2) (P< 1 x 10(-8))]. A statistical model based upon stepwise regression was generated and completely separated the tissue types: ductal Measure = 448+669 x (s/10(-3) mm2)-10.7 x PE (1/%), R2=1.0 and P<8 x 10(-10)., Conclusions: The very different MR results in the glandular-ductal versus stromal-low ductal tissues suggest that these tissues have different underlying structure. These results support the hypothesis that Gd-DTPA does not enter healthy prostatic glands or ducts. This may explain the higher PE and lower that previously have been reported in prostate cancer versus healthy tissue.

Purpose: To establish an inverse planning set of parameters (class solution) to boost dominant intra-prostatic lesion (DIL) defined by MRI/MRSI., Methods: For 15 patients, DIL were contoured on CT or MR images and a class solution was developed to boost the DIL under the dosimetric requirements of the RTOG-0321 protocol. To determine the maximum attainable level of boost for each patient, 5 different levels were considered, at least 110%, 120%, 130%, 140% and 150% of the prescribed dose. The maximum attainable level was compared to the plan without boost using cumulative dose volume histogram (DVH)., Results: DIL dose escalation was feasible for 11/15 patients under the requirements. The planning target volume (PTV) dose was slightly increased, while the DIL dose was significantly increased without any violation of requirements. With slight adjustments of the dose constraint parameters, the dose escalation was feasible for 13/15 patients under requirements., Conclusion: Using a class solution, a dose escalation of the MRI/MRSI defined DIL up to 150% while complying with RTOG dosimetric requirements is feasible. This HDR brachytherapy approach to dose escalation allows a significant dose increase to the tumor while maintaining an acceptable risk of complications.

Purpose: To compare the data quality and ease of use of four endorectal-coil probe setups for prostate MRI., Materials and Methods: Four endorectal-coil probe setups were compared: 1) air-inflated probe; 2) perfluorocarbon (PFC)-inflated probe; 3) rigid, smaller prototype coil; and 4) rigid, smaller coil designed for biopsying the prostate. Signal-to-noise ratio (SNR), positioning, shimming, MRI motion artifact, and MR spectroscopic imaging (MRSI) spectral quality were assessed., Results: Rigid coils provided approximately 2.5-fold higher SNR than inflatable coils near the peripheral zone midline. The biopsy probe sensitivity decreased dramatically by the apex. The rigid probes, as compared to the inflatable probes, took longer to place (10 +/- 2 vs. 7 +/- 2 minutes, P < 0.0002), tended to be placed too superiorly, required repositioning more often (73% vs. 20%, P < 0.003), and had higher motion artifacts (P < 0.001). Shimming time was least for the PFC-inflated probe (2 +/- 0.5 minutes, P < 0.05). The air-inflated probe produced larger linewidths (P < 0.01) and tended to have longer shim times (7 +/- 4 minutes) and poorer spectral quality., Conclusion: The inflatable coil is a good clinical choice due to ease of use, good coverage, and low motion artifacts. PFC-inflation is recommended as it provided higher quality data than air-inflation. The rigid, smaller probes have higher SNR and produce less tissue distortion and may be preferred for certain applications., ((c) 2008 Wiley-Liss, Inc.)

Magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging (MRSI) have been shown to be very useful for identifying prostate cancers. For high sensitivity, the MRI/MRSI examination is often acquired with an endorectal probe that may cause a substantial deformation of the prostate and surrounding soft tissues. Such a probe is removed prior to radiation therapy treatment. To register diagnostic probe-in magnetic resonance (MR) images to therapeutic probe-out MR images for treatment planning, a new deformable image registration method is developed based on biomechanical modeling of soft tissues and estimation of uncertain tissue parameters using nonlinear optimization. Given two-dimensional (2-D) segmented probe-in and probe-out images, a finite element method (FEM) is used to estimate the deformation of the prostate and surrounding tissues due to displacements and forces resulting from the endorectal probe. Since FEM requires tissue stiffness properties and external force values as input, the method estimates uncertain parameters using nonlinear local optimization. The registration method is evaluated using images from five balloon and five rigid endorectal probe patient cases. It requires on average 37 s of computation time on a 1.6 GHz Pentium-M PC. Comparing the prostate outline in deformed probe-out images to corresponding probe-in images, the method obtains a mean Dice Similarity Coefficient (DSC) of 97.5% for the balloon probe cases and 98.1% for the rigid probe cases. The method improves significantly over previous methods (P < 0.05) with greater improvement for balloon probe cases with larger tissue deformations.

Endorectal coils (ERCs) are used for acquiring high spatial resolution magnetic resonance (MR) images of the human prostate. The goal of this study is to determine the impact of an expandable versus a rigid ERC on changes in the location and deformation of the prostate gland and subsequently on registering prostate images acquired with and without an ERC. Sagittal and axial T2 weighted MR images were acquired from 25 patients receiving a combined MR imaging/MR spectroscopic imaging staging exam for prostate cancer. Within the same exam, images were acquired using an external pelvic phased array coil both alone and in combination with either an expandable ERC (MedRad, Pittsburgh, PA) or a rigid ERC (USA Instruments, Aurora, OH). Rotations, translations and deformations caused by the ERC were measured and compared. The ability to register images acquired with and without the ERC using a manual rigid-body registration was assessed using a similarity index (SI). Both ERCs caused the prostate to tilt anteriorly with an average tilt of 18.5 degrees (17.4 +/- 9.9 and 19.5 +/- 11.3 degrees, mean +/- standard deviation, for expandable and rigid ERC, respectively). However, the expandable coil caused a significantly larger distortion of the prostate as compared to the rigid coil; compressing the prostate in the anterior/posterior direction by 4.1 +/- 3.0 mm vs 1.2 +/- 2.2 mm (14.5% vs 4.8%) (p < 0.0001), and widening the prostate in the right/left direction by 3.8 +/- 3.7 mm vs 1.5 +/- 3.1 mm (8.3% vs 3.4%) (p = 0.004). Additionally, the ability to manually align prostate images acquired with and without ERC was significantly (p < 0.0001) better for the rigid coil (SI = 0.941 +/- 0.008 vs 0.899 +/- 0.033, for the rigid and expandable coils, respectively). In conclusion, the manual rigid-body alignment of prostate MR images acquired with and without the ERC can be improved through the use of a rigid ERC.

This study characterized dynamic contrast-enhanced (DCE) MRI of prostate tissues: cancerous peripheral zone (PZ), normal PZ, stromal benign prostatic hyperplasia (BPH), and glandular BPH. MRI, MRSI, and DCE MRI were performed on 25 patients. Tissues were identified with MRI, MRSI, and (when available) biopsy results. Motion between MRI and DCE MRI, and within DCE MRI was assessed and manually corrected. To assess tissue and patient effects, native T1's were measured in 12 of 25 patients, and DCE MRI results were normalized to muscle enhancement. Regions of cancer had a higher peak enhancement (P < 0.006), faster enhancement rate (P < 0.0008), and faster washout slope (P < 0.05) than normal PZ tissues. Stromal BPH had the fastest enhancement rate (P < 0.003) of all tissues and tended to have the greatest enhancement. Intersequence motion averaged 2.6 mm and reached 7.9 mm. Motion within DCE MRI was generally minimal (<2 pixels), but one case showed a large shift that would have confounded the results. Native T1's were similar across the prostatic tissues. Interpatient variability in DCE MRI was only partially reduced by normalization to muscle. DCE MRI of the prostate discriminated PZ cancer from normal PZ tissues and predominantly stromal and glandular BPH.

Purpose: To identify and overcome challenges in using dynamic contrast-enhanced magnetic resonance imaging (MRI) to distinguish tumor from nontumor in the cervical lymph nodes of patients with squamous cell carcinoma of the head and neck., Materials and Methods: Signal-to-noise ratio (S/N), motion, node heterogeneity, and tissue normalizations were examined. Twenty-one patients with squamous cell carcinoma of the head and neck were scanned before a neck dissection (two-dimensional fast spoiled gradient-echo: 10 locations/13 seconds). Peak time, peak enhancement, maximum upslope, and washout slope were measured in pathologically confirmed tumor and nontumor nodes and in the submandibular gland and the sternocleidomastoid muscle., Results: Surface coil arrays provided high coverage and high S/N. Motion averaged 1.1 pixels and was corrected. Large tumor nodes were heterogeneous in their contrast enhancement, while the nontumor nodes were homogeneous. The contrast enhancement parameters were significantly different for all regions except for the submandibular gland compared to the nontumor nodes., Conclusion: Challenges of dynamic imaging of cervical lymph nodes were overcome and significant differences were found between the tumor and nontumor nodes, indicating that dynamic imaging is feasible and may aid this patient population., (Copyright 2003 Wiley-Liss, Inc.)

Background and Purpose: Morphologic assessment by conventional imaging methods of lymph node metastases in patients with squamous cell carcinoma of the head and neck is, at best, insensitive. Doppler sonography has shown that lymph node metastases exhibit alterations in the number of vessels and blood flow. We assessed the ability of dynamic contrast-enhanced MR imaging to differentiate normal from diseased nodes in this patient population., Methods: Twenty-one patients with newly diagnosed squamous cell carcinoma and no previous treatment were studied with the use of a head and neck phased array surface coil. Anatomic imaging included high resolution T1-weighted, fat-saturated fast spin-echo T2-weighted, and contrast-enhanced T1-weighted imaging (0.99-1.32 mm(3) voxels). The dynamic contrast-enhanced MR imaging was performed by using a 2D fast spoiled gradient recalled sequence with single dose bolus injection of contrast agent. Calculated values included time to peak, peak enhancement, maximum slope, and washout slope for the enhancement. All patients underwent neck dissection as part of their indicated treatment, and imaging results were correlated with pathologic findings., Results: Dynamic contrast-enhanced MR imaging and pathology comparisons were obtained for 68 nodes. There was significantly longer time to peak (P <.001), lower peak enhancement (P <.05), lower maximum slope (P <.01), and slower washout slope (P <.05) in the tumor-involved nodes compared with the normal nodes., Conclusion: Analysis of dynamic contrast-enhanced MR imaging can differentiate normal from diseased lymph nodes in patients with squamous cell carcinoma of the head and neck.

Background and Purpose: Previous studies have primarily used single-voxel techniques to obtain MR spectra from the neonatal brain. In this study, we applied 3D MR spectroscopic imaging techniques to detect the spatial distribution of MR spectroscopic imaging-detectable compounds in premature and term infants. The goals were to test the feasibility of obtaining 3D MR spectroscopic images of newborns, assess the spatial variations of metabolite levels, and determine age-dependent differences in MR spectroscopic imaging data., Methods: MR spectroscopic imaging data were acquired from nine premature (postconceptional age, 30-34 weeks) and eight term (postconceptional age, 38-42 weeks) neonates, all with normal clinical and neurologic outcomes. A specialized point-resolved spectroscopy sequence with very selective saturation pulses was used to select a region encompassing the majority of the brain. Phase encoding in three dimensions was performed in a 17-minute acquisition time to obtain 3D spectral arrays with a 1.0 cm(3) nominal spatial resolution., Results: This study showed the feasibility of detecting the 3D distributions of choline, creatine, and N-acetylaspartate resonances in the neonatal brain. Significant spectral differences were detected among anatomic locations and between the premature and term groups., Conclusion: This initial study indicates that 3D MR spectroscopic imaging of the neonatal brain can detect anatomic and age-dependent variations in metabolite levels. This technique seems to be a powerful tool to assess the metabolic differences between anatomic regions and to follow the changes in cellular metabolites with brain maturation. This study also indicates the need for determining topologic and age-matched normative values before metabolic abnormalities in neonates can be accurately assessed by MR spectroscopy.

Background and Purpose: Tumor progression is often difficult to distinguish from nonneoplastic treatment response on the basis of MR images alone. This study correlates metabolite levels measured by preoperative MR spectroscopic (MRS) imaging with histologic findings of biopsies, obtained during image-guided resections of brain mass lesions, to clarify the potential role of MRS in making this distinction., Methods: Twenty-nine patients with brain tumors underwent high-resolution (0.2-1 cc) 3D proton MRS imaging and MR imaging before undergoing surgery; 11 had a newly diagnosed neoplasm, and 18 had recurrent disease. Surgical biopsies were obtained from locations referenced on MR images by guidance with a surgical navigation system. MR spectral voxels were retrospectively centered on each of 79 biopsy locations, and metabolite levels were correlated with histologic examination of each specimen., Results: All mass lesions studied, whether attributable to tumor or noncancerous effects of previous therapy, showed abnormal MR spectra compared with normal parenchyma. When the pattern of MRS metabolites consisted of abnormally increased choline and decreased N-acetyl aspartate (NAA) resonances, histologic findings of the biopsy specimen invariably was positive for tumor. When choline and NAA resonances were below the normal range, histologic findings were variable, ranging from radiation necrosis, astrogliosis, and macrophage infiltration to mixed tissues that contained some low-, intermediate-, and high-grade tumor., Conclusion: This study demonstrated that 3D MRS imaging can identify regions of viable cancer, which may be valuable for guiding surgical biopsies and focal therapy. Regions manifesting abnormal MR spectra had a mixture of histologic findings, including astrogliosis, necrosis, and neoplasm.

Although proton magnetic resonance spectroscopic imaging (1H-MRSI) has been shown to be effective for localizing tumor in patients with gliomas, it is not a routinely used clinical tool. This is due, in part, to the lack of a standardized, objective method for analyzing spectra. We present an automated technique for a) selecting a population of voxels from each patient that have the spectral features of normal brain regions, and b) using the selected voxels as internal controls for quantifying the probability of abnormality at each voxel location. The technique was demonstrated on a phantom, 14 normal volunteers, and 30 patients with histologically proven tumor. In addition, we demonstrated the usefulness of the method for monitoring patients in serial studies from two glioma patients with progressive disease.

Background and Purpose: Elevated relative regional cerebral blood volume (rCBV) reflects the increased microvascularity that is associated with brain tumors. The purpose of this study was to investigate the potential role of rCBV in the determination of recurrent/residual disease in patients with treated gliomas., Methods: Thirty-one rCBV studies were performed in 19 patients with treated gliomas. All patients also had proton MR spectroscopy and conventional MR imaging. Regions of abnormality were identified on conventional MR images by two neuroradiologists and compared with rCBV and MR spectroscopic data. Metabolites and rCBV were quantified and compared in abnormal regions., Results: In high-grade tumors, rCBV values were proportional to choline in regions of tumor and nonviable tissue. Although the presence of residual/recurrent disease was often ambiguous on conventional MR images, the rCBV maps indicated regions of elevated vascularity in all low-grade tumors and in 12 of 17 grade IV lesions. Regions of elevated and low rCBV corresponded well with spectra, indicating tumor and nonviable tissue, respectively., Conclusion: This study suggests that rCBV maps and MR spectroscopy are complementary techniques that may improve the detection of residual/recurrent tumor in patients with treated gliomas. Compared with the spectra, the rCBV maps may better reflect the heterogeneity of the tumor regions because of their higher resolution. The multiple markers of MR spectroscopy enable better discrimination between normal and abnormal tissue than do the rCBV maps.

High-resolution MR imaging and spectroscopic imaging were used to study differences in proton spectra between cortical gray matter and subcortical white matter in 23 normal volunteers using a 1.5 T scanner and surface coil receivers. A point-resolved spectroscopy (PRESS) volume with an 8 x 8 x 8 phase-encoding matrix was used to acquire over 1900 0.09-0.2 cc spectral voxels. The high-resolution (0.7 x 0.7 x 0.8 mm3 or 0.8 x 0.8 x 1 mm3) images were corrected for the surface coil reception profile and segmented into cerebrospinal fluid (CSF) and gray and white matter to correlate with the spectra. The data showed that N-acetyl aspartate (NAA) and creatine (Cr) were higher in the gray matter than in the white matter (NAA(g/w) = 1.4+/-0.36, Cr(g/w) = 1.4+/-0.41). Choline was significantly lower in the gray matter of the occipital lobe than in the white matter (0.73+/-0.19), but not significantly different in the other regions. NAA/Cho was found to be significantly higher in the occipital lobe than in the left frontal or vertex regions.