Comparison of 18F-FLT PET and 18F-FDG PET in esophageal cancer.

18F-FDG PET has gained acceptance for staging of esophageal cancer. However, FDG is not tumor specific and false-positive results may occur by accumulation of FDG in benign tissue. The tracer 18F-fluoro-3'-deoxy-3'-L-fluorothymidine (18F-FLT) might not have these drawbacks. The aim of this study was to investigate the feasibility of 18F-FLT PET for the detection and staging of esophageal cancer and to compare 18F-FLT PET with 18F-FDG PET. Furthermore, the correlation between 18F-FLT and 18F-FDG uptake and proliferation of the tumor was investigated. METHODS: Ten patients with biopsy-proven cancer of the esophagus or gastroesophageal junction were staged with CT, endoscopic ultrasonography, and ultrasound of the neck. In addition, all patients underwent a whole-body 18F-FLT PET and 18F-FDG PET. Standardized uptake values were compared with proliferation expressed by Ki-67 positivity. RESULTS: 18F-FDG PET was able to detect all esophageal cancers, whereas 18F-FLT PET visualized the tumor in 8 of 10 patients. Both 18F-FDG PET and 18F-FLT PET detected lymph node metastases in 2 of 8 patients. 18F-FDG PET detected 1 cervical lymph node that was missed on 18F-FLT PET, whereas 18F-FDG PET showed uptake in benign lesions in 2 patients. The uptake of 18F-FDG (median standardized uptake value [SUV(mean)], 6.0) was significantly higher than 18F-FLT (median SUV(mean), 3.4). Neither 18F-FDG maximum SUV (SUV(max)) nor 18F-FLT SUV(max) correlated with Ki-67 expression in the linear regression analysis. CONCLUSION: In this study, uptake of 18F-FDG in esophageal cancer is significantly higher compared with 18F-FLT uptake. 18F-FLT scans show more false-negative findings and fewer false-positive findings than do 18F-FDG scans. Uptake of 18F-FDG or 18F-FLT did not correlate with proliferation.     

The Effect of Medical Elastic Compression Stockings with Different Slope Values on Edema

BACKGROUND: Medical elastic compression stockings are widely used in venous diseases. Their effects on the venous system have been shown in the past. Up to now, little is known about the slope or stiffness factor of stockings. OBJECTIVE: To evaluate the effect of different slope and stiffness factors of medical elastic compression stockings on the venous system. METHODS: Examinations were carried out in 29 legs of 25 different patients (12 men, 13 women) with a mean age of 66.0 years. All patients were known with chronic venous insufficiency. On all these patients three different elastic medical compression stockings were tested; one with a low slope, one with a high slope, and one with a low slope but a higher pressure at the ankle. The tests were carried out by determining capillary filtration rate (CFR) with air-plethysmography (APG) while wearing the stockings. RESULTS: The mean value of the CFR without wearing a stocking was 4.65 ml/min (SD = 1.68), with Compriform (low slope, 30 mmHg) the mean CFR was 3.54 ml/min (SD = 1.22), with Bellavar (high slope, 30 mmHg) a mean CFR of 3.15 ml/min (SD = 1.17) was found, and the mean CFR related to Fast-fit (low slope, 34.5 mmHg) was 3.02 ml/min (SD = 1.12). There is a highly statistically significant difference in CFR between no stockings and wearing a stocking (paired Student's t-test; P < 0.01). Regarding the individual stocking, there is a highly statistically significant difference in CFR between the Compriform and the other two stockings (paired Student's t-test; P < 0.01). Between Bellavar and the Fast-fit the difference was not statistically significant. CONCLUSIONS: There is a statistically significant difference in CFR, and consequently in the development of edema, between not wearing an elastic compression stocking and wearing an elastic compression stocking. There is also a statistically significant difference in CFR between elastic compression stockings with the same compression, but a low slope profile and a high slope profile. Stockings with a low slope, but a higher compression may perform as well as stockings with a higher slope but a lower compression in reducing the CFR. In patients with a strong tendency to develop edema it may be advisable to prescribe stockings with a high slope profile.     

Test‐retest reliability of the default mode network in a multi‐centric fMRI study of healthy elderly: Effects of data‐driven physiological noise correction techniques

Understanding how to reduce the influence of physiological noise in resting state fMRI data is important for the interpretation of functional brain connectivity. Limited data is currently available to assess the performance of physiological noise correction techniques, in particular when evaluating longitudinal changes in the default mode network (DMN) of healthy elderly participants. In this 3T harmonized multisite fMRI study, we investigated how different retrospective physiological noise correction (rPNC) methods influence the within‐site test‐retest reliability and the across‐site reproducibility consistency of DMN‐derived measurements across 13 MRI sites. Elderly participants were scanned twice at least a week apart (five participants per site). The rPNC methods were: none (NPC), Tissue‐based regression, PESTICA and FSL‐FIX. The DMN at the single subject level was robustly identified using ICA methods in all rPNC conditions. The methods significantly affected the mean z‐scores and, albeit less markedly, the cluster‐size in the DMN; in particular, FSL‐FIX tended to increase the DMN z‐scores compared to others. Within‐site test‐retest reliability was consistent across sites, with no differences across rPNC methods. The absolute percent errors were in the range of 5–11% for DMN z‐scores and cluster‐size reliability. DMN pattern overlap was in the range 60–65%. In particular, no rPNC method showed a significant reliability improvement relative to NPC. However, FSL‐FIX and Tissue‐based physiological correction methods showed both similar and significant improvements of reproducibility consistency across the consortium (ICC = 0.67) for the DMN z‐scores relative to NPC. Overall these findings support the use of rPNC methods like tissue‐based or FSL‐FIX to characterize multisite longitudinal changes of intrinsic functional connectivity. Hum Brain Mapp 37:2114–2132, 2016. © 2016 Wiley Periodicals, Inc.     

The Delphic oracle: a multidisciplinary defense of the gaseous vent theory

Ancient historical references consistently describe an intoxicating gas, produced by a cavern in the ground, as the source of the power at the oracle of Delphi. These ancient writings are supported by a series of associated geological findings. Chemical analysis of the spring waters and travertine deposits at the site show these gases to be the light hydrocarbon gases methane, ethane, and ethylene. The effects of inhaling ethylene, a major anesthetic gas in the mid-20th century, are similar to those described in the ancient writings. We believe the probable cause of the trancelike state of the Priestess (the Pythia) at the oracle of Delphi during her mantic sessions was produced by inhaling ethylene gas or a mixture of ethylene and ethane from a naturally occurring vent of geological origin.     

Deficits of memory,executive functioning and attention following infarction in the thalamus; a study of 22 cases with localised lesions

The thalamus plays a crucial role in memory, executive functioning and attention. It remains, however, unclear whether thalamic structures have specific roles in each of these functions. We tested 22 cases of thalamic infarction, proven with MR imaging, using experimental and established neuropsychological tests. We performed a lesion-overlap study in standardised stereotactic space of patients sharing a certain deficit, corrected for the lesion distribution of patients without such deficits and determined the regions of interest using an atlas of the human thalamus. We checked for additional, non-thalamic, damage and for deficient comprehension and perception that would preclude interpretation of the results. Non-thalamic damage such as white matter lesions, hippocampal atrophy, sulcal widening and infarctions occur significantly more often in patients aged over 60. The patients with additional damage overlapped to a major degree with those who showed loss of orientation, or lack of comprehension of the test requirements. In the 10 patients judged 'clean', we observed a deficit of episodic long-term memory with relative sparing of intellectual capacities and short-term memory when the mammillo-thalamic tract was damaged. Lesions including the medial dorsal nucleus, midline nuclei and/or intralaminar nuclei accompany executive dysfunctioning. Reduced simple processing speed and attention are associated with age, but not with a particular structure in the thalamus. Complex attention deficits follow damage to the intralaminar nuclei.We conclude that the analysis of structure-function relationships must take into account extra-structure damage which may explain cognitive deficits. Separate thalamic structures are involved in memory, executive functioning and attention.     

Brain lesions in patients visiting a memory clinic with postconcussional sequelae after mild to moderate brain injury

Postconcussional disorder after a relatively mild head injury is common. Although a partial organic etiology is presumed, little imaging evidence exists for this assumption. In this study, patients with mild to moderate brain injury (median Glasgow Coma Scale score of 14) had more parenchymal brain lesions than control subjects (P=0.02). Additionally, the authors investigated the potential of quantifying brain injury by the magnetization transfer ratio (MTR). The curve amplitude of the MTR histogram was used as a measure of normal white matter. Patients had a lower curve amplitude than control subjects (P=0.008). This study provides evidence of persistent traumatic brain alterations in patients who sustained a relatively mild traumatic brain injury.     

Recurrent leg ulcers in a young man with hyperhomocysteinemia,factor V Leiden and impaired fibrinolysis

We present a young male patient referred to our hospital with leg ulcers on both legs that were more than 3 years refractory to standard treatment with compression therapy. By thrombophilia screening factor V Leiden mutation, hyperhomocysteinemia and evidence for impaired fibrinolysis were found. Treatment with folic acid in combination with long-term oral anticoagulant therapy was added to non-elastic compression therapy. The leg ulcers showed slow improvement and complete healing within 3 years. During a 6-year follow-up period neither new thrombo-embolic events occurred nor recurrence of ulcerations. This case suggests a potential synergistic pathogenic role of factor V Leiden, hyperhomocysteinemia and impaired fibrinolysis in the development of postthrombotic syndrome and his sequelae. We postulate that increased formation of thrombi in the microcirculation of the skin in combination with ambulatory venous hypertension due to recurrent deep venous thrombosis might explain our observation.     

Local staging of prostate cancer using magnetic resonance imaging: a meta-analysis

Our objective was to determine the influence of patient-, study design-, and imaging protocol characteristics on staging performance of MR imaging in prostate cancer. In an electronic literature search and review of bibliographies (January 1984 to May 2000) the articles selected included data on sensitivity and specificity for local staging. Subgroup analyses examined the influence of age, prostate specific antigen, tumor grade, hormonal pre-treatment, stage distribution, publication year, department of origin, verification bias, time between biopsy and MR imaging; consensus reading, study design, consecutive patients, sample size, histology preparation, imaging planes, fast spin echo, fat suppression, endorectal coil, field strength, resolution, glucagon, contrast agents, MR spectroscopy, and dynamic contrast-enhanced MRI. Seventy-one articles and five abstracts were included, yielding 146 studies. Missing values were highly prevalent for patient characteristics and study design. Publication year, sample size, histologic gold standard, number of imaging planes, turbo spin echo, endorectal coil, and contrast agents influenced staging performance ( p=0.05). Due to poor reporting it was not possible to fully explain the heterogeneity of performance presented in the literature. Our results suggest that turbo spin echo, endorectal coil, and multiple imaging planes improve staging performance. Studies with small sample sizes may result in higher staging performance.     

Quantification of 5-HT1A receptors in human brain using p-MPPF kinetic modelling and PET

Serotonin-1A (5-HT(1A)) receptors are implicated in neurochemical mechanisms underlying anxiety and depression and their treatment. Animal studies have suggested that 4-(2'-methoxyphenyl)-1-[2'-[ N-(2"-pyridinyl)- p-[(18)F]fluorobenzamido] ethyl] piperazine ( p-MPPF) may be a suitable positron emission tomography (PET) tracer of 5-HT(1A) receptors. To test p-MPPF in humans, we performed 60-min dynamic PET scans in 13 healthy volunteers after single bolus injection. Metabolite quantification revealed a fast decrease in tracer plasma concentration, such that at 5 min post injection about 25% of the total radioactivity in plasma corresponded to p-MPPF. Radioactivity concentration was highest in hippocampus, intermediate in neocortex and lowest in basal ganglia and cerebellum. The interactions between p-MPPF and 5-HT(1A) receptors were described using linear compartmental models with plasma input and reference tissue approaches. The two quantification methods provided similar results which are in agreement with previous reports on 5-HT(1A) receptor brain distribution. In conclusion, our results show that p-MPPF is a suitable PET radioligand for 5-HT(1A) receptor human studies.