OBJECTIVE The purpose of this study was to characterize human brown adipose tissue (BAT) with chemical-shift water-fat MRI and to determine whether trends and differences in fat-signal fractions and T2* relaxation times between BAT and white adipose tissue (WAT) are consistently observed postmortem and in vivo in infants, adolescents, and adults. MATERIALS AND METHODS A postmortem body and eight patients were studied. A six-echo spoiled gradient-echo chemical-shift water-fat MRI sequence was performed at 3 T to jointly quantify fat-signal fraction and T2* in interscapular-supraclavicular BAT and subcutaneous WAT. To confirm BAT identity, biopsy and histology served as the reference in the postmortem study and PET/CT was used in five of the eight patients who required examination for medical care. RESULTS Fat-signal fractions and T2* times were lower in BAT than in WAT in the postmortem example and in seven of eight patients. With the exception of one case, nominal comparisons between brown and white adipose tissues were statistically significant (p < 0.05). Between subjects, a large range of fat-signal fraction values was observed in BAT but not in WAT. CONCLUSION We have shown that fat-signal fractions and T2* values jointly derived from chemical-shift water-fat MRI are lower in BAT than in WAT likely because of differences in cellular structures, triglyceride content, and vascularization. The two metrics can serve as complementary biomarkers in the detection of BAT.

Purpose To compare fat-signal fractions (FFs) and T2* values between brown (BAT) and white (WAT) adipose tissue located within the supraclavicular fossa and subcutaneous depots, respectively. Materials and Methods Twelve infants and 39 children were studied. Children were divided into lean and overweight/obese sub-groups. Chemical-shift-encoded water-fat MRI was used to quantify FFs and T2* metrics in the supraclavicular and adjacent subcutaneous adipose tissue depots. Linear regression and t-tests were performed. Results Infants had lower supraclavicular FFs than children (p<0.01) but T2* values were similar (p=0.5). Lean children exhibited lower supraclavicular FFs and T2* values than overweight children (p<0.01). In each individual infant and child, supraclavicular FFs were consistently lower than adjacent subcutaneous FFs. Supraclavicular T2* values were consistently lower than subcutaneous T2* values in children, but not in infants. FFs in both depots were positively correlated with age and weight in infants (p<0.01). In children, they were correlated with weight and BMI (p<0.01), but not age. Correlations between T2* and anthropometric variables existed in children (p<0.01), but were absent in infants. Conclusion Cross-sectional comparisons suggest variations in FF and T2* values in the supraclavicular and subcutaneous depots of infants and children, which are potentially indicative of physiological differences in adipose tissue fat content, amount, and metabolic activity.

This study reviewed the literature for the extent of neuroimaging findings in boxers, indicative of traumatic brain injury (TBI) as identified in magnetic resonance imaging (MRI). The study then utilized a systematic checklist approach to assess 100 unselected consecutive 1.5- and 3.0-Tesla MRI examinations of professional unarmed combatants to determine the extent of identifiable TBI findings. The percentage of positive findings and the localization of lesions were quantified using the checklist that included the MRI findings previously reported in the medical literature. Seventy-six percent of the unarmed combatants had at least one finding that may be associated with TBI: 59% hippocampal atrophy, 43% cavum septum pellucidum, 32% dilated perivascular spaces, 29% diffuse axonal injury, 24% cerebral atrophy, 19% increased lateral ventricular size, 14% pituitary gland atrophy, 5% arachnoid cysts, and 2% had contusions. Statistical relationships were found between number of bouts and lateral ventricular size (tau-b = 0.149, p = 0.0489), with years of fighting correlating with the presence of dilated perivascular spaces (tau-b = 0.167, p = 0.0388) and diffuse axonal injury (tau-b = 0.287, p = 0.0013) findings. The improved resolution and increased signal-to-noise ratio on 1.5- and 3.0-Tesla high-field MRI systems defines the range of pathological variations that may occur in professional unarmed combatants. Additionally, the use of a systematic checklist approach insures evaluation for all possible TBI-related abnormalities. This knowledge can be used to anticipate the regions of potential brain pathology for radiologists and emergency medicine physicians, and provides important information for evaluating unarmed combatants relative to their safety and long-term neurocognitive outcome.

DTI measures of muscle structure strongly correlated with muscle strength and adiposity in boys with DMD in this pilot study, although these markers may be more reflective of fat replacement rather than muscle damage in later stages of the disease. Further studies in presymptomatic younger children are needed to assess the ability of DTI to detect early changes in DMD.

We reviewed 61 consecutive patients with renal abscesses who were treated between 1972 and 1988 to determine whether the patient characteristics and mortality differed from those of patients treated during the preceding 2 decades. The results demonstrate that the predisposing conditions, symptomatology, abnormal physical findings, abnormal laboratory results, abnormal radiographic findings and infecting organisms of patients with renal abscesses have not changed during the last 40 years. Ultrasonography and computerized tomography, which became available in the 1970s, identified 35 of 38 (92%) and 23 of 24 (96%) abscesses, respectively. In 57 cases (97%) the abscess was drained and the patients survived. In 4 cases the abscess escaped clinical detection and contributed to patient death. The marked improvement of survival among patients with renal abscesses during the last 2 decades is attributable to improved diagnostic precision and, probably, improved antimicrobial therapy and supportive care.