Detection and differentiation of inflammatory versus fibromatous Crohn's disease strictures: prospective comparison of 18F-FDG-PET/CT, MR-enteroclysis, and transabdominal ultrasound versus endoscopic/histologic evaluation.

BACKGROUND: Differentiation between inflammatory and fibromatous strictures in Crohn's disease (CD) is difficult but crucial for therapeutic decisions. The aim of this study was to assess the best noninvasive imaging method for the detection and differentiation of inflammatory and fibromatous stenoses in CD in comparison to endoscopic and histologic evaluation. METHODS: Patients with suspected CD strictures were included. According to a formalized endoscopic and histologic protocol, strictures were classified as inflammatory, mixed, and fibrostenotic. Strictures were further analyzed using fluorine 18-labeled fluoro-2-deoxy-D-glucose ((18) FDG) / positron emission tomography (PET) low-dose computed tomography (CT), magnetic resonance (MR) enteroclysis and transabdominal ultrasound using standardized scoring systems. RESULTS: Thirty patients with 37 strictures were evaluated (inflamed n = 22; mixed n = 12, fibromatous n = 3). (18) FDG-PET/CT detected 81%, MR-enteroclysis 81%, and ultrasound 68% of the strictures. Correct differentiation rates of strictures were 57% for MRE, 53% for (18) FDG-PET/CT, and 40% for ultrasound. Differences of detection rates and differentiation rates were not statistically significant. When combining transabdominal ultrasound with (18) FDG-PET/CT or MR-enteroclysis all strictures that required invasive treatment were detected. CONCLUSIONS: Detection rates of the strictures were not significantly different between (18) FDG-PET/CT, MR-enteroclysis, and ultrasound. Despite good stricture detection rates relating to our gold standard, (18) FDG-PET/CT nor MR-enteroclysis nor ultrasound can accurately differentiate inflamed from fibrotic strictures. A combination of MR-enteroclysis and ultrasound as well as a combination of (18) FDG-PET/CT and ultrasound resulted in a 100% detection rate of strictures requiring surgery or endoscopic dilation therapy, suggesting the combination of these methods as an alternative to endoscopy at least in the group of patients not able to perform an adequate bowel preparation.

Spontaneous central melatonin secretion and resorption kinetics of exogenous melatonin: a ventricular CSF study.

Pineal secretion of melatonin, a potential sleep-inducing agent, is stimulated by nighttime darkness. To gain better insight into the control of melatonin physiology in man, we studied melatonin concentrations in ventricular cerebrospinal fluid (v-CSF). In four patients aged 1-4 yr with therapeutic v-CSF drainage, including one with lumbar CSF (l-CSF) drainage, CSF samples were collected sequentially over 24-hr periods. One further patient with severe sleep disturbance had one collection period under chloral hydrate and another after oral melatonin administration. Reduction of light intensity or night periods, respectively, led to increased melatonin levels. At the moment of falling asleep, additional melatonin peaks were observed in v-CSF but not in l-CSF. Oral melatonin, but not chloral hydrate, caused a rapid increase in CSF melatonin between 10 and 80 min after intake, raising levels far beyond physiological concentrations. The commencement of sleep is associated with an additional melatonin peak v-CSF which is independent of baseline secretion during the day-night cycle. The possibility is discussed that the induction of sleep might depend on a critical level or increased melatonin concentrations, which can be achieved with orally administered melatonin.

Pattern of cortical reorganization in amyotrophic lateral sclerosis: a functional magnetic resonance imaging study.

Depending on individual lesion location and extent, reorganization of the human motor system has been observed with a high interindividual variability. In addition, variability of forces exerted, of motor effort, and of movement strategies complicates the interpretation of functional imaging studies. We hypothesize that a general pattern of reorganization can be identified if a homogeneous patient population is chosen and experimental conditions are controlled. Patients with amyotrophic lateral sclerosis (ALS) and healthy volunteers were trained to perform a simple finger flexion task with 10% of each individual's maximum grip force with constant movement amplitude and frequency. The activation pattern in ALS patients was distinctly different to that in healthy controls: In ALS patients, motor cortex activation was located more anteriorly, encompassing the premotor gyrus. The cluster volume within the supplementary motor area (SMA) was higher and shifted toward the pre-SMA. Contralateral inferior area 6 and bilateral parietal area 40 revealed higher cluster volumes. Our results demonstrate a general pattern of functional changes after motor neuron degeneration. They support the concept of a structurally parallel and functionally specialized organization of voluntary motor control. Degeneration of the first and second motor neurons leads to enhanced recruitment of motor areas usually involved in initiation and planning of movement. Partial compensation between functionally related motor areas seems to be a strategy to optimize performance if the most efficient pathway is unavailable.