BOLD background gradient contributions in diffusion‐weighted fMRI—comparison of spin‐echo and twice‐refocused spin‐echo sequences

The interaction (‘cross terms’) between diffusion‐weighting gradients and susceptibility‐induced background gradient fields around vessels has an impact on apparent diffusion coefficient (ADC) measurements and diffusion‐weighted functional magnetic resonance imaging (DFMRI) experiments. Monte‐Carlo (MC) simulations numerically integrating the Bloch equations for a large number of random walks in a vascular model were used to investigate to what extent such interactions would influence the extravascular signal change as well as the ADC change observed in DFMRI experiments. The vascular model consists of a set of independent, randomly oriented, infinite cylinders whose internal magnetic susceptibility varies as the state changes between rest and activation. In such a network, the cross terms result in the observation of a functional increase in ADC accompanied by a descending percent signal change with increasing diffusion weighting. It is shown that the twice‐refocused spin‐echo sequence permits sufficient yet not total suppression of such effects compared to the standard Stejskal‐Tanner spin‐echo diffusion weighting under experimentally relevant conditions. Copyright © 2010 John Wiley & Sons, Ltd.     

Kommt die Defi-Drohne?

Die Anaesthesiologie - Der Mangel an automatischen externen Defibrillatoren (AED) und die fehlende Kenntnis von Ersthelfern im Umgang mit diesen Geräten haben in Deutschland zu einer...     

Entscheidungshilfe zur Patientenzuweisung bei Verdacht auf COVID-19

Notfall + Rettungsmedizin - Während einer Pandemielage sind Patienten mit Verdacht auf COVID-19 auch im Rahmen von Rettungsdienstalarmierungen zu versorgen. Um ein adäquates Vorgehen zu...     

Behandlung von Blutungen in der Schwangerschaft

Archives of Gynecology and Obstetrics -     

Neuritis retrobulbaris (Leber) und endokrines System

Ohne Zusammenfassung     

Multiple injections for low back pain: What’s the future?

To examine the strength of evidence available for multiple facet joint injections (FJIs) and medial branch blocks (MBBs), and to report on the variations in the NHS England framework using the getting it right first time (GIRFT) data. Systematic review using patient, intervention, comparison, outcome and study strategy. The literature search using Cochrane, MEDLINE and EMBASE databases using MeSH terms: lumbar spine, spinal injection and facet joint (“Appendix A”). Three studies were identified that investigated the efficacy of multiple FJIs or MBBs. None of these studies reported sustained positive outcomes at long-term follow-up. There is a paucity of levels I and II evidence available for the efficacy of multiple FJIs and MBBs in treating low back pain. GIRFT data show a high degree of variation in the use of multiple FJIs, which would not be supported by the literature. These slides can be retrieved under Electronic Supplementary Material.     

Ambulatory blood pressure monitoring

Ambulatory blood pressure monitoring (ABPM) in adults is proving to be useful. The aim of this study was to determine if ABPM is accurate in the lower blood pressure range encountered in children and, equally important, whether it is acceptable to children. Thirty one children, between the ages of 6 and 18 years, were assessed using an ambulatory blood pressure monitor that uses an auscultatory method. Blood pressure was measured in the contralateral arm with a mercury sphygmomanometer and an oscillometric device at the beginning and end of the study for comparison. Over a blood pressure range of 90-130 mm Hg systolic and 40-80 mm Hg diastolic, a close agreement was found with the sphygmomanometer; the limits of agreement (+/- 2 SD) were 11.6 mm Hg for systolic blood pressure and 13.6 mm Hg for diastolic blood pressure. The bias was less than 1.0 mm Hg. The ambulatory device was worn by all patients for at least 16 hours with an average of 52 recordings per patient. The majority found the device comfortable to wear and were not woken from sleep.     

Hypoxia and hypercapnia in infants with mild laryngomalacia

We evaluated 15 infants with laryngomalacia and 12 healthy infants to determine their risk of hypoxia and hypercapnia as complications of partial upper airway obstruction. Transcutaneous carbon dioxide pressure and oxygen pressure were recorded continuously overnight with episodes of hypercapnia and/or hypoxia scored for frequency, duration, and relationship to activity. Episodes occurred in 12 infants with laryngomalacia and eight control infants. Infants with laryngomalacia had significantly more episodes. The greatest decrease in transcutaneous oxygen pressure was 29 mm Hg and increase in transcutaneous carbon dioxide pressure was 31 mm Hg, both occurring in infants with laryngomalacia. Three infants had prolonged episodes of hypoxia and hypercapnia. History or physical examination did not distinguish those infants with laryngomalacia who had hypercapnia and/or hypoxia from those without episodes. Two- to 15-month follow-ups in 13 infants with laryngomalacia revealed that symptoms were unchanged or improved. Twelve of these 13 infants had normal growth without developmental delay or other complications. These results demonstrate that episodes of hypoxia and hypercapnia occur more frequently in infants with laryngomalacia than in control infants; however, their apparent risk for complications is low.     

Rapid destructive osteo-arthritis of the hip

A case of an unusual destructive hip osteoarthropathy with a plain-film record of rapid joint destruction is reported. In the absence of any laboratory or pathological support for other pathology this is thought to be an uncommon example of erosive or inflammatory osteo-arthritis in a large joint.     

Hydrosalpingeal fluid inhibits in-vitro embryonic development in a murine model

Recent evidence describing a suboptimal clinical outcome in women with hydrosalpinges who undergo in-vitro fertilization (IVF) and embryo transfer suggests a potential deleterious effect of this fluid on in- utero embryo development. Consequently, we evaluated in-vitro mouse embryo development in the presence of hydrosalpingeal fluid (HF) collected from 10 infertile women of reproductive age. Chemical analyses showed both similarities and differences of these fluids to reported values for fluids collected from non-diseased Fallopian tubes. The HF had a significant deleterious effect upon mouse embryo cleavage and development to the expanded and hatched blastocyst stage, although the effect was variable among patients. Dilution of HF to 30% concentration with culture medium failed to negate this effect. This argues against the effect resulting from a relative lack of critical, supportive component(s) in the HF. Additionally, further experiments performed with cultures under an oil overlay significantly reduced the embryotoxicity of the HF. This evidence suggests there may be a lipophilic factor that can impair embryo development. The relatively poor IVF-embryo transfer success in women with proximally patent hydrosalpinges may be explained, at least in part, by reflux of a lipophilic embryotoxic factor(s) into the uterine cavity.