Faculty Bibliography

Approximately half of head and neck carcinomas arise from the oral cavity. Imaging plays an essential role in the preoperative evaluation of oral cavity carcinomas. MR imaging is particularly advantageous in the evaluation of the oral cavity, with better depiction of the anatomy in this region and reduction of dental artifacts compared with CT. MR is also the preferred imaging modality for the evaluation of bone marrow invasion and perineural tumor spread, which are findings critical for treatment planning. Advanced MR imaging techniques may potentially better delineate true tumor extent, determine lymph node metastases, and predict treatment response.

Langerhans cell histiocytosis (LCH) encompasses a range of clinical presentations. Pure osseous involvement is referred to as eosinophilic granuloma (EG), whereas systemic involvement can either be classified as Hand-Schuller-Christian disease or Letterer-Siwe syndrome. It is estimated that of the total incidence of LCH (0.5 per 100,000 children per year in the United States), nearly 70% are categorized as EG (1). We describe a case of clinically occult calvarial eosinophilic granuloma brought to medical attention only after a traumatic event led to scalp and epidural hemorrhage at the site of the lesion. Osseous EG initially presents as a painful or tender mass, at times even mimicking osteomyelitis. Computed tomography (CT) reveals a lytic lesion with beveled edges. Magnetic resonance (MR) imaging is often non-specific, but usually demonstrates a marrow-replacing process that is T1 hypointense, T2 hyperintense, with homogenous enhancement. The complex MR imaging findings in our case provided a unique perspective regarding the presentation of EG. Once pathology established eosinophilic granuloma, skeletal survey confirmed the lesion was solitary, despite a compelling history of present illness.

BACKGROUND: Sarcoidosis affects the central nervous system more frequently than previously appreciated. The diagnosis of neurosarcoidosis is often delayed, potentially leading to serious complications. Symptoms, when present, are not specific, may be subtle and resemble those of other neurologic diseases. REVIEW SUMMARY: During the past decade, significant progress has been made in understanding the epidemiology and pathophysiology of neurosarcoidosis, as well as the ability to diagnose and treat this disease. Studies have shown that the optimal diagnostic imaging modality for neurosarcoidosis is magnetic resonance imaging with gadolinium as it enhances visualization of granulomatous infiltration in neural tissue. Subclinical neurosarcoidosis may not be uncommon in patients with sarcoidosis. It is now evident that neurosarcoidosis does not invariably present as a catastrophic event. Adverse effects associated with high-dose systemic corticosteroids, the standard therapy, have discouraged practitioners from initiating treatment in the absence of significant symptomatic neurologic disease. However, other immunosuppressive agents as well newer biologic agents have emerged as an effective, well-tolerated therapeutic alternative to corticosteroids, which are often effective in corticosteroid-recalcitrant cases. CONCLUSION: Neurologists should be aware of the varying presentations of neurosarcoidosis since early recognition of neurologic involvement in patients with undiagnosed or proven sarcoidosis is currently possible and critical to the prevention of disabling complications

Although the pathogenic mechanisms of inflammatory bowel diseases are not fully understood, colonic microbiota may affect the induction of colonic inflammation, and some probiotics and prebiotics have been reported to suppress colitis. The inhibitory effects of brown rice fermented by Aspergillus oryzae (FBRA), a fiber-rich food, on the induction of acute colitis by dextran sulfate sodium (DSS) were examined. Feeding a 5% and 10% FBRA-containing diet significantly decreased the ulcer and erosion area in the rat colon stained with Alcian blue. In another experiment, 10% FBRA feeding decreased the ulcer index (percentage of the total length of ulcers in the full length of the colon) and colitis score, which were determined by macroscopic observation. It also decreased myeloperoxidase activity in the colonic mucosa. Viable cell numbers of Lactobacillus in the feces decreased after DSS administration and was reversely correlated with severity of colitis, while the cell number of Enterobacteriaceae increased after DSS treatment and was positively correlated with colitis severity. These results indicate that FBRA has a suppressive effect on the induction of colitis by DSS and suggest FBRA-mediated modification of colonic microbiota.

Institutional review board approval and informed consent were obtained for this HIPAA-compliant study. The purpose of this study was to prospectively evaluate sensitivity and specificity of various estimated perfusion parameters at three-dimensional (3D) perfusion magnetic resonance (MR) imaging of the liver in the diagnosis of advanced liver fibrosis (stage >or= 3), with histologic analysis, liver function tests, or MR imaging as the reference standard. Whole-liver 3D perfusion MR imaging was performed in 27 patients (17 men, 10 women; mean age, 55 years) after dynamic injection of 8-10 mL of gadopentetate dimeglumine. The following estimated perfusion parameters were measured with a dual-input single-compartment model: absolute arterial blood flow (F(a)), absolute portal venous blood flow (F(p)), absolute total liver blood flow (F(t)) (F(t) = F(a) + F(p)), arterial fraction (ART), portal venous fraction (PV), distribution volume (DV), and mean transit time (MTT) of gadopentetate dimeglumine. Patients were assigned to two groups (those with fibrosis stage <or= 2 and those with fibrosis stage >or= 3), and the nonparametric Mann-Whitney test was used to compare F(a), F(p), F(t), ART, PV, DV, and MTT between groups. Receiver operating characteristic curve analysis was used to assess the utility of perfusion estimates as predictors of advanced liver fibrosis. There were significant differences for all perfusion MR imaging-estimated parameters except F(p) and F(t). There was an increase in F(a), ART, DV, and MTT and a decrease in PV in patients with advanced fibrosis compared with those without advanced fibrosis. DV had the best performance, with an area under the receiver operating characteristic curve of 0.824, a sensitivity of 76.9% (95% confidence interval: 46.2%, 94.7%), and a specificity of 78.5% (95% confidence interval: 49.2%, 95.1%) in the prediction of advanced fibrosis

Brown rice fermented by Aspergillus oryzae (FBRA) is a fiber-rich food. Effects of dietary administration of FBRA on rat fecal microbiota composition were examined. Male Wistar rats were fed a basal diet or a 5% FBRA- or 10% FBRA-containing diet, and fecal microbiota was analyzed by culture and terminal-restriction fragment length polymorphism (T-RFLP) analysis. The viable cell number of lactobacilli significantly increased after feeding 10% FBRA diet for 3 weeks compared with that in the basal diet group and that in the same group at the beginning of the experiment (day 0). An increase in the viable cell number of lactobacilli was also observed after feeding 10% FBRA for 12 weeks compared with the effect of a basal diet. T-RFLP analysis showed an increase in the percentage of lactobacilli cells in feces of rats fed 10% FBRA for 14 weeks. Lactobacilli strains isolated from rat feces were divided into six types based on their randomly amplified polymorphic DNA (RAPD) patterns, and they were identified as Lactobacillus reuteri, L. intestinalis and lactobacilli species based on homology of the partial sequence of 16S rDNA. FBRA contains lactic acid bacteria, but their RAPD patterns and identified species were different from those in rat feces. These results indicated that dietary FBRA increases the number of lactobacilli species already resident in the rat intestine.