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Background Adolescents and women with anorexia nervosa have increased bone marrow fat and decreased bone formation, at least in part due to hormonal changes leading to preferential stem cell differentiation to adipocytes over osteoblasts. Objective The purpose of this study was to evaluate marrow fat content and correlate with age and disease severity using knee MRI with T1 relaxometry (T1-R) and MR spectroscopy (MRS) in 70 adolescents with anorexia nervosa. Materials and methods We enrolled 70 girls with anorexia nervosa who underwent 3-T knee MRI with coronal T1-W images, T1-R and single-voxel proton MRS at 30 and 60 ms TE. Metaphyses were scored visually on the T1-W images for red marrow. Visual T1 score, T1 relaxometry values, MRS lipid indices and fat fractions were analyzed by regression on age, body mass index (BMI) and bone mineral density (BMD) as disease severity markers. MRS measures included unsaturated fat index, T2 water, unsaturated and saturated fat fractions. Results All red marrow measures declined significantly with age. T1-R values were associated negatively with BMI and BMD for girls ≤16 years ( P =0.03 and P =0.002, respectively) and positively for those≥17 years ( P =0.05 and P =0.003, respectively). MRS identified a strong inverse association between T2 water and saturated fat fraction from 60 ms TE data ( r =−0.85, P <0.0001). There was no association between unsaturated fat index and BMI or BMD. Conclusions The association between T1 and BMI and BMD among older girls suggests more marrow fat in those with severe anorexia nervosa. In contrast, the physiological association between marrow fat content and age remained dominant in younger patients. The strong association between T2 water and saturated fat may relate to the restricted mobility of water with increasing marrow fat.

Purpose To assess the transverse relaxation time T 2 and diffusion coefficient D before and following exercise in the tibialis anterior muscle and determine whether T 2 and D values were correlated. Methods Measurements of T 2 and D were performed at 3 T within axial slices through the calf muscles of six healthy volunteers at 95 s intervals before and for 10–12 min after a dorsiflexion exercise to exhaustion. Results The mean ± standard deviation (SD) of T 2 and D before exercise were 32 ± 1.55 ms and 1.52  ±  0.15 μm 2 /ms, and after exercise were 43 ± 2.5 ms and 1.72  ±  0.13 μm 2 /ms, respectively. The mean ± SD inter-individual recovery times of the % change in T 2 and D after exercise were 7.9  ±  4.2 and 10.9 ± 7.0 min, respectively. The T 2 and D values showed a significant correlation throughout the experiments ( r 2  =  0.45). Conclusions The increase in T 2 of skeletal muscle after exercise is correlated with the increase of the diffusion coefficient D and the recovery times appear similar, indicating that any model used to explain T 2 increases with exercise must also account for increased diffusion coefficients.

Objective To determine if tumor cell density and percentage of Gleason pattern within an outlined volumetric tumor region of interest (TROI) on whole-mount pathology (WMP) correlate with apparent diffusion coefficient (ADC) values on corresponding TROIs outlined on pre-operative MRI. Methods Men with biopsy-proven prostate adenocarcinoma undergoing multiparametric MRI (mpMRI) prior to prostatectomy were consented to this prospective study. WMP and mpMRI images were viewed using 3D Slicer and each TROI from WMP was contoured on the high b-value ADC maps (b0, 1400). For each TROI outlined on WMP, TCD (tumor cell density) and the percentage of Gleason pattern 3, 4, and 5 were recorded. The ADC mean , ADC 10th percentile , ADC 90th percentile , and ADC ratio were also calculated in each case from the ADC maps using 3D Slicer. Results Nineteen patients with 21 tumors were included in this study. ADC mean values for TROIs were 944.8 ± 327.4 vs. 1329.9 ± 201.6 mm 2 /s for adjacent non-neoplastic prostate tissue ( p  < 0.001). ADC mean , ADC 10th percentile , and ADC ratio values for higher grade tumors were lower than those of lower grade tumors ( mean 809.71 and 1176.34 mm 2 /s, p  = 0.014; 10th percentile 613.83 and 1018.14 mm 2 /s, p  = 0.009; ratio 0.60 and 0.94, p  = 0.005). TCD and ADC mean ( ρ  = −0.61, p  = 0.005) and TCD and ADC 10th percentile ( ρ  = −0.56, p  = 0.01) were negatively correlated. No correlation was observed between percentage of Gleason pattern and ADC values. Conclusion DWI MRI can characterize focal prostate cancer using ADC ratio , ADC 10th percentile , and ADC mean , which correlate with pathological tumor cell density.

PurposeTo compare diagnostic performance of PI-RADSv2 with ADC parameters to identify clinically significant prostate cancer (csPC) and to determine the impact of csPC definitions on diagnostic performance of ADC and PI-RADSv2.MethodsWe retrospectively identified treatment-naïve pathology-proven peripheral zone PC patients who underwent 3T prostate MRI, using high b-value diffusion-weighted imaging from 2011 to 2015. Using 3D slicer, areas of suspected tumor (T) and normal tissue (N) on ADC (b = 0, 1400) were outlined volumetrically. Mean ADCT, mean ADCN, ADCratio (ADCT/ADCN) were calculated. PI-RADSv2 was assigned. Three csPC definitions were used: (A) Gleason score (GS) ≥ 4 + 3; (B) GS ≥ 3 + 4; (C) MRI-based tumor volume >0.5 cc. Performances of ADC parameters and PI-RADSv2 in identifying csPC were measured using nonparametric comparison of receiver operating characteristic curves using the area under the curve (AUC).ResultsEighty five cases met eligibility requirements. Diagnostic performances (AUC) in identifying csPC using three definitions were: (A) ADCT (0.83) was higher than PI-RADSv2 (0.65, p = 0.006); (B) ADCT (0.86) was higher than ADCratio (0.68, p < 0.001), and PI-RADSv2 (0.70, p = 0.04); (C) PI-RADSv2 (0.73) performed better than ADCratio (0.56, p = 0.02). ADCT performance was higher when csPC was defined by A or B versus C (p = 0.038 and p = 0.01, respectively). ADCratio performed better when csPC was defined by A versus C (p = 0.01). PI-RADSv2 performance was not affected by csPC definition.ConclusionsWhen csPC was defined by GS, ADC parameters provided better csPC discrimination than PI-RADSv2, with ADCT providing best result. When csPC was defined by MRI-calculated volume, PI-RADSv2 provided better discrimination than ADCratio. csPC definition did not affect PI-RADSv2 diagnostic performance.

We report an MR imaging phenomenon that can lead to misinterpretation. The unique appearance of the soft tissues and bone marrow in a 19-year-old severely malnourished woman with anorexia nervosa raised concerns about technical failure or systemic pathology. Due to extreme fat depletion, the T1-weighted images appeared to be fat-suppressed and the fat-suppressed fluid-sensitive images appeared to be non-fat-suppressed (“flip-flopped”). Failure to recognize the influence of a patient’s overall nutritional status on MR images may cause confusion and misdiagnosis.

Abstract Background: Fatty liver is highly prevalent among obese children and represents a major risk factor for chronic liver diseases and severe metabolic complications. Methods: We randomly assigned 17 obese children 8–17 years of age with fatty liver to either an experimental low-glycemic-load or conventional low-fat diet for 6 months. Participants in both groups received nutrition education and behavioral counseling of equal intensity. The primary outcome was hepatic lipid content measured by proton magnetic resonance spectroscopy. Secondary outcomes included change in visceral fat, BMI, anthropometrics, alanine aminotransferase (ALT), and insulin resistance. Results: A total of 16 participants completed the study. Reported glycemic load decreased in the low-glycemic-load group and reported dietary fat decreased in the low-fat group. At baseline, liver fat was 23.8% [standard deviation (SD) 12.2] in the low-glycemic-load group and 29.3% (14.1) in the low-fat group. Liver fat decreased substantially in both groups at 6 months expressed as absolute percentage change, with no between-group differences [−8.8 (standard error (SE) 4.1) vs. −10.5 (3.7)%, respectively, p=0.76 for group×time interaction]. Secondary outcomes also improved on both diets, with no between-group differences. Baseline and change in ALT were strongly associated with hepatic fat content. Conclusions: Weight-reducing diets focused either on glycemic load or dietary fat improved hepatic steatosis over 6 months. Additional research is needed to determine whether these diets differ in effectiveness over the long term. Trial Registration: clinicaltrials.gov Identifier: NCT00480922

Intramyocellular lipids (IMCL) play an important role in muscle metabolism. 1 H magnetic resonance spectroscopy is the method of choice for non-invasive assessment of IMCL. However, IMCL quantitation is hampered by the larger overlapping resonances of extramyocellular lipids (EMCL). A phantom that mimics EMCL and IMCL, i.e., the 0.2-ppm resonance splitting, would be useful for testing acquisition strategies and post-processing algorithms. Here, we propose a phantom that consists of a cylindrical bottle filled with dairy cream and sunflower oil. Similar to EMCL, the oil (CH 2 ) n protons resonate at 1.5 ppm; similar to IMCL, the spherical shape of droplets in cream results in (CH 2 ) n protons resonating at 1.3 ppm. The relative amount of IMCL versus EMCL can be easily controlled in a systematic and exact fashion by displacing the voxel of interest across the cream–oil interface. This phantom is of simple construction and made of inexpensive and readily available materials, and should be of value in testing both acquisition and spectral analysis strategies in the context of ICML/ECML studies.

Seventy-one-year-old identical twin brothers with chronic lead poisoning were identified from an occupational medicine clinic roster. Both were retired painters, but one brother (J.G.) primarily removed paint and had a history of higher chronic lead exposure. Patella and tibia bone lead concentrations measured by K-X-ray fluorescence in each brother were 5-10 times those of the general population and about 2.5 times higher in J.G. than in his brother (E.G.). Magnetic resonance spectroscopy (MRS) studies examined N-acetylaspartate:creatine ratios, a marker of neuronal density. Ratios were lower in J.G. than in his brother. Scores on neurocognitive tests that assess working memory/executive function were below expectation in both twins. Short-term memory function was dramatically worse in J.G. than in his brother. These results demonstrate some of the more subtle long-term neurologic effects of chronic lead poisoning in adults. In particular, they suggest the presence of frontal lobe dysfunction in both twins, but more dramatic hippocampal dysfunction in the brother with higher lead exposure. The MRS findings are consistent with the hypothesis that chronic lead exposure caused neuronal loss, which may contribute to the impairment in cognitive function. Although a causal relation cannot be inferred, the brothers were genetically identical, with similar life experiences. Although these results are promising, further study is necessary to determine whether MRS findings correlate both with markers of lead exposure and tests of cognitive function. Nevertheless, the results point to the potential utility of MRS in determining mechanisms of neurotoxicity not only for lead but also for other neurotoxicants as well.

With the increase in obese and overweight children, nonalcoholic fatty liver disease has become more prevalent in the pediatric population. Appreciating subtleties of magnetic resonance (MR) signal intensity behavior from fatty livers under different imaging conditions thus becomes important to pediatric radiologists. We report an initially confusing signal behavior—increased signal from fatty livers when fat-suppression pulses are applied in an opposed-phase gradient echo imaging sequence—and seek to explain the physical mechanisms for this paradoxical signal intensity behavior. Abdominal MR imaging at 3 T with a 3-D volumetric interpolated breath-hold (VIBE) sequence in the opposed-phase condition (TR/TE 3.3/1.3 ms) was performed in five obese boys (14±2 years of age, body mass index >95th percentile for age and sex) with spectroscopically confirmed fatty livers. Two VIBE acquisitions were performed, one with and one without the use of chemical shift selective (CHESS) pulse fat suppression. The ratios of fat-suppressed over non-fat-suppressed signal intensities were assessed in regions-of-interest (ROIs) in five tissues: subcutaneous fat, liver, vertebral marrow, muscle and spleen. The boys had spectroscopically estimated hepatic fat levels between 17% and 48%. CHESS pulse fat suppression decreased subcutaneous fat signals dramatically, by more than 85% within regions of optimal fat suppression. Fatty liver signals, in contrast, were elevated by an average of 87% with CHESS pulse fat suppression. Vertebral marrow signal was also significantly elevated with CHESS pulse fat suppression, while spleen and muscle signals demonstrated only small signal increases on the order of 10%. We demonstrated that CHESS pulse fat suppression actually increases the signal intensity from fatty livers in opposed-phase gradient echo imaging conditions. The increase can be attributed to suppression of one partner of the opposed-phase pair that normally contributes to the destructive interference between water and fat. The result is a paradoxical increase in signal from fatty liver that will depend on both fat content and the relative longitudinal relaxation times of fat methylene protons and water.

The purpose of this study is to primarily evaluate the lumen area and secondarily evaluate wall area measurements of in vivo lower extremity peripheral vein bypass grafts patients using high spatial resolution, limited field of view, cardiac gated, black blood inner volume three-dimensional fast spin echo MRI. Fifteen LE-PVBG patients prospectively underwent ultrasound followed by T1-weighted and T2-weighted magnetic resonance (MR) imaging. Lumen and vessel wall areas were measured by direct planimetry. For graft lumen areas, T1- and T2-weighted measurements were compared with ultrasound. For vessel wall areas, differences between T1- and T2-weighted measurements were evaluated. There was no significant difference between ultrasound and MR lumen measurements, reflecting minimal MR blood suppression artifact. Graft wall area measured from T1-weighted images was significantly larger than that measured from T2-weighted images ( P  < 0.001). The mean of the ratio of T1- versus T2-weighted vessel wall areas was 1.59 (95% CI: 1.48–1.69). The larger wall area measured on T1-weighted images was due to a significantly larger outer vessel wall boundary. Very high spatial resolution LE-PVBG vessel wall MR imaging can be performed in vivo, enabling accurate measurements of lumen and vessel wall areas and discerning differences in those measures between different tissue contrast weightings. Vessel wall area differences suggest that LE-PVBG vessel wall tissues produce distinct signal characteristics under T1 and T2 MR contrast weightings.