Elliptical localization with pulsed second‐order fields (ECLIPSE) for robust lipid suppression in proton MRSI

Proton MRSI has great clinical potential for metabolic mapping of the healthy and pathological human brain. Unfortunately, the promise has not yet been fully achieved due to numerous technical challenges related to insufficient spectral quality caused by magnetic field inhomogeneity, insufficient RF transmit power and incomplete lipid suppression. Here a robust, novel method for lipid suppression in ¹H MRSI is presented. The method is based on 2D spatial localization of an elliptical region of interest using pulsed second‐order spherical harmonic (SH) magnetic fields. A dedicated, high‐amplitude second‐order SH gradient setup was designed and constructed, containing coils to generate Z2, X2Y2 and XY magnetic fields. Simulations and phantom MRI results are used to demonstrate the principles of the method and illustrate the manifestation of chemical shift displacement. ¹H MRSI on human brain in vivo demonstrates high quality, robust suppression of extracranial lipids. The method allows a wide range of inner or outer volume selection or suppression and should find application in MRSI, reduced‐field‐of‐view MRI and single‐volume MRS.     

Fractures of the foot and ankle

Fractures of the foot and ankle are common in all age groups. Soft tissue swelling, smoking and co-morbidities such as diabetes mellitus and peripheral vascular disease should be considered when forming the management plan.Careful attention to neurovascular status and the soft tissue envelope of the foot and ankle is essential to the management of these injuries especially where crush injuries have occurred. Open fractures should be treated urgently with a combined approach with the plastic surgeons.A good understanding of surgical anatomy is key to managing these fractures. Good intra-articular involvement and ligamentous stability are crucial in predicting long-term prognosis.The core principles of management are: to maintain the soft tissue envelope (minimize disruption); to obtain appropriate alignment; restoration of joint surfaces; and rehabilitation to obtain optimum function.     

Large-scale analysis of interindividual variability in single and paired-pulse TMS data

ObjectiveThis study brought together over 60 transcranial magnetic stimulation (TMS) researchers to create the largest known sample of individual participant single and paired-pulse TMS data to date, enabling a more comprehensive evaluation of factors driving response variability.MethodsAuthors of previously published studies were contacted and asked to share deidentified individual TMS data. Mixed-effects regression investigated a range of individual and study level variables for their contribution to variability in response to single and paired-pulse TMS data.Results687 healthy participant’s data were pooled across 35 studies. Target muscle, pulse waveform, neuronavigation use, and TMS machine significantly predicted an individual’s single-pulse TMS amplitude. Baseline motor evoked potential amplitude, motor cortex hemisphere, and motor threshold (MT) significantly predicted short-interval intracortical inhibition response. Baseline motor evoked potential amplitude, test stimulus intensity, interstimulus interval, and MT significantly predicted intracortical facilitation response. Age, hemisphere, and TMS machine significantly predicted MT.ConclusionsThis large-scale analysis has identified a number of factors influencing participants’ responses to single and paired-pulse TMS. We provide specific recommendations to minimise interindividual variability in single and paired-pulse TMS data.SignificanceThis study has used large-scale analyses to give clarity to factors driving variance in TMS data. We hope that this ongoing collaborative approach will increase standardisation of methods and thus the utility of single and paired-pulse TMS.     

Concurrent mycosis fungoides and intravascular large B-cell lymphoma in a single patient

Mycosis fungoides (MF) is an indolent, uncommon, non-Hodgkin T-cell lymphoma of the skin. It classically presents with patches, plaques, and tumors and may rarely show spread to internal organs or bone marrow. Up to 7.5% of MF patients may be diagnosed with a second malignancy. Intravascular large B-cell lymphoma (IVLBCL) is an exceedingly rare non-Hodgkin B-cell lymphoma characterized by predominant growth of large neoplastic cells in the lumina of blood vessels. This case presents with an unusual confluence of two rare diagnoses, MF and IVLBCL, made more remarkable by the presence of both diagnoses on a single skin biopsy sample.     

A Two-Dimensional Second Order Conservative Front-Tracking Method with an Original Marker Advection Approach Based on Jump Relations

A two-dimensional front-tracking method is developed for handling complex shape interfaces satisfying the volume conservation. In order to validate the proposed front-tracking method, a complete convergence study is carried out on several analytical test cases for which the interface is widely stretched and deformed. Comparisons to different existing approaches show that our front-tracking method is second order accurate in space with lower errors than existing interface tracking techniques of the literature.We also propose an original marker advection method which takes into account the jump relations valid at interface in order to deal with the contrast of physical properties encountered in two-phase flow simulations. The conservative front-tracking method computed in this work is shown to be able to describe interfaces with high accuracy even for poorly resolved Eulerian grids.     

Pronation on weightbearing radiographs does not correlate with pronation from weightbearing CT scans

IntroductionIn hallux valgus (HV), first metatarsal pronation is increasingly recognized as an important aspect of the deformity. The purpose of this study was to compare pronation in HV patients determined from the shape of the lateral head of the first metatarsal on AP weightbearing radiographs with pronation calculated from weightbearing CT (WBCT) scans.MethodsPatients were included in this study if they had preoperative and 5-month postoperative WBCT scans and corresponding weightbearing AP radiographs of the affected foot. Pronation of the first metatarsal on WBCT scans was measured using a 3D CAD model and the alpha angle and categorized into four groups on radiographs. Association between pronation groups on radiographs and WBCT scans was determined using Spearman correlation coefficients (r_s) and by comparing mean WBCT pronation of the first metatarsal between plain radiograph pronation groups.ResultsAgreement between the two observers’ pronation on radiographs was good (k = 0.634) and moderate (k = 0.501), respectively. There was no correlation between radiographic pronation and the 3D CAD model (r_s < 0.15). Preoperatively, there was weak correlation between the alpha angle and the radiographic pronation groups (r_s = 0.371, P = 0.048) although this relationship did not hold postoperatively (r_s = 0.330, P = 0.081). There was no difference in mean pronation calculated on WBCT scans between the plain radiographic groups.ConclusionPronation of the first metatarsal measured on weightbearing AP radiographs had moderate interobserver agreement and was only weakly associated with pronation measured from WBCT scans. These results suggest that first metatarsal pronation measured on weightbearing radiographs is not a substitute for pronation measured on WBCT scans.Level of evidenceIII, retrospective cohort study.