Estimation of liver iron concentration by dual energy CT images: influence of X-ray energy on sensitivity

In hemochromatosis an abnormal accumulation of iron is present in parenchymal organs and especially in liver. Among the several techniques employed to diagnose the iron overload, magnetic resonance imaging (MRI) and Computed Tomography (CT) are the most promising non-invasive ones. MRI is largely used but shows limitation including an overestimation of iron and inability to quantify iron at very high concentrations. Therefore, some research groups are focusing on the estimation of iron concentration by CT images. Single X-ray CTs are not able to accurately perform this task in case of the presence of confounding factors (e.g., fat). A potential solution to overcome this concern is the employment of Dual-Energy CT (DECT). The aim of this work is to investigate influence of the kVp and mAs on CT number sensitivity to iron concentration. A phantom with test tubes filled with homogenized porcine liver at different iron concentrations, has been scanned with DECT at different mAs. The images have been analyzed using an ad-hoc developed algorithm which allows minimizing the influence of air bubbles present in the homogenized. Data show that the sensitivity is strongly influenced by kVp (its value almost halves from 80 kVp to 140 kVp; e.g. 0.41 g·μmol(-1) and 0.19 g·μmol(-1) at 80 kVp/120 mAs and 140 kVp/60 mAs respectively), on the other hand the influence of mAs value is negligible.

Exploring two-dimensional electron gases with two-dimensional Fourier transform spectroscopy

The dephasing of the Fermi edge singularity excitations in two modulation doped single quantum wells of 12 nm and 18 nm thickness and in-well carrier concentration of ∼4 × 10(11) cm(-2) was carefully measured using spectrally resolved four-wave mixing (FWM) and two-dimensional Fourier transform (2DFT) spectroscopy. Although the absorption at the Fermi edge is broad at this doping level, the spectrally resolved FWM shows narrow resonances. Two peaks are observed separated by the heavy hole/light hole energy splitting. Temperature dependent "rephasing" (S1) 2DFT spectra show a rapid linear increase of the homogeneous linewidth with temperature. The dephasing rate increases faster with temperature in the narrower 12 nm quantum well, likely due to an increased carrier-phonon scattering rate. The S1 2DFT spectra were measured using co-linear, cross-linear, and co-circular polarizations. Distinct 2DFT lineshapes were observed for co-linear and cross-linear polarizations, suggesting the existence of polarization dependent contributions. The "two-quantum coherence" (S3) 2DFT spectra for the 12 nm quantum well show a single peak for both co-linear and co-circular polarizations.

[Proposed global treatment algorithm for hallux rigidus according to evidence-based medicine]

INTRODUCTION

Hallux rigidus is the most common arthritis of the foot and ankle. There are numerous reviews on the surgical treatment, but few publications that address the effectiveness of conservative treatment.

OBJECTIVE

To present a comprehensive algorithm for treatment of all grades of this disease.

METHODS

Literature search in the following sources: Pubmed and PEDro database (physiotherapy evidence database) until October 2013 for articles on treatment hallux rigidus to record levels of evidence.

RESULTS

A total of 112 articles were obtained on conservative treatment and 609 on surgical treatment. Finally, only 4 met the inclusion criteria.

CONCLUSIONS

The use of orthoses or footwear modifications, infiltration with hyaluronate, cheilectomy in moderate degrees and the metatarsophalangeal arthrodesis for advanced degrees, are the only procedures contrasted with grade B or moderate evidence in the treatment of hallux rigidus.

Feasibility study of a randomised controlled trial to compare (deferred) androgen deprivation therapy and cryotherapy in men with localised radiation-recurrent prostate cancer

BACKGROUND

Salvage therapeutic options for biochemical failure after primary radiation-based therapy include radical prostatectomy, cryoablation, high-intensity focused ultrasound (HIFU), brachytherapy (for post-EBRT patients) and androgen deprivation therapy (ADT). ADT and salvage prostate cryoablation (SPC) are two commonly considered treatment options for RRPC. However, there is an urgent need for high-quality clinical studies to support evidence-based decisions on treatment choice. Our study aims to determine the feasibility of randomising men with RRPC for treatment with ADT and SPC.

METHODS

The randomised controlled trial (CROP) was developed, which incorporated protocols to assess parameters relating to cryotherapy procedures and provide training workshops for optimising patient recruitment. Analysis of data from the recruitment phase and patient questionnaires was performed.

RESULTS

Over a period of 18 months, 39 patients were screened for eligibility. Overall 28 patients were offered entry into the trial, but only 7 agreed to randomisation. The majority reason for declining entry into the trial was an unwillingness to be randomised into the study. 'Having the chance of getting cryotherapy' was the major reason for accepting the trial. Despite difficulty in retrieving cryotherapy temperature parameters from prior cases, 9 of 11 cryotherapy centres progressed through the Cryotherapists Qualification Process (CQP) and were approved for recruiting into the CROP study.

CONCLUSIONS

Conveying equipoise between the two study arms for a salvage therapy was challenging. The use of delayed androgen therapy may have been seen as an inferior option. Future cohort studies into available salvage options (including prostate cryotherapy) for RRPC may be more acceptable to patients than randomisation within an RCT.

A randomised, phase II trial of the DNA-hypomethylating agent 5-aza-2'-deoxycytidine (decitabine) in combination with carboplatin vs carboplatin alone in patients with recurrent, partially platinum-sensitive ovarian cancer

BACKGROUND

Our previous laboratory and clinical data suggested that one mechanism underlying the development of platinum resistance in ovarian cancer is the acquisition of DNA methylation. We therefore tested the hypothesis that the DNA hypomethylating agent 5-aza-2'-deoxycytodine (decitabine) can reverse resistance to carboplatin in women with relapsed ovarian cancer.

METHODS

Patients progressing 6-12 months after previous platinum therapy were randomised to decitabine on day 1 and carboplatin (AUC 6) on day 8, every 28 days or carboplatin alone. The primary objective was response rate in patients with methylated hMLH1 tumour DNA in plasma.

RESULTS

After a pre-defined interim analysis, the study closed due to lack of efficacy and poor treatment deliverability in 15 patients treated with the combination. Responses by GCIG criteria were 9 out of 14 vs 3 out of 15 and by RECIST were 6 out of 13 vs 1 out of 12 for carboplatin and carboplatin/decitabine, respectively. Grade 3/4 neutropenia was more common with the combination (60% vs 15.4%) as was G2/3 carboplatin hypersensitivity (47% vs 21%).

CONCLUSIONS

With this schedule, the addition of decitabine appears to reduce rather than increase the efficacy of carboplatin in partially platinum-sensitive ovarian cancer and is difficult to deliver. Patient-selection strategies, different schedules and other demethylating agents should be considered in future combination studies.

A mysterious back pain

IgG4-related disease is a fibroinflammatory condition that affects many different organs. The common pathological findings of this disease include storiform fibrosis and dense infiltration of lymphocytes rich in IgG4-positive plasma cells. We herein presents the diagnosis and treatment of a case with a newly recognized condition - IgG4-related pachymeningitis.

Healthcare-associated outbreak of meticillin-resistant Staphylococcus aureus bacteraemia: role of a cryptic variant of an epidemic clone

Background

New strains of meticillin-resistant Staphylococcus aureus (MRSA) may be associated with changes in rates of disease or clinical presentation. Conventional typing techniques may not detect new clonal variants that underlie changes in epidemiology or clinical phenotype.

Aim

To investigate the role of clonal variants of MRSA in an outbreak of MRSA bacteraemia at a hospital in England.

Methods

Bacteraemia isolates of the major UK lineages (EMRSA-15 and -16) from before and after the outbreak were analysed by whole-genome sequencing in the context of epidemiological and clinical data. For comparison, EMRSA-15 and -16 isolates from another hospital in England were sequenced. A clonal variant of EMRSA-16 was identified at the outbreak hospital and a molecular signature test designed to distinguish variant isolates among further EMRSA-16 strains.

Findings

By whole-genome sequencing, EMRSA-16 isolates during the outbreak showed strikingly low genetic diversity (P < 1 × 10⁻⁶, Monte Carlo test), compared with EMRSA-15 and EMRSA-16 isolates from before the outbreak or the comparator hospital, demonstrating the emergence of a clonal variant. The variant was indistinguishable from the ancestral strain by conventional typing. This clonal variant accounted for 64/72 (89%) of EMRSA-16 bacteraemia isolates at the outbreak hospital from 2006.

Conclusions

Evolutionary changes in epidemic MRSA strains not detected by conventional typing may be associated with changes in disease epidemiology. Rapid and affordable technologies for whole-genome sequencing are becoming available with the potential to identify and track the emergence of variants of highly clonal organisms.

Neuraxial block, death and serious cardiovascular morbidity in the POISE trial

BACKGROUND

This post hoc analysis aimed to determine whether neuraxial block was associated with a composite of cardiovascular death, non-fatal myocardial infarction (MI) and non-fatal cardiac arrest within 30 days of randomization in POISE trial patients.

METHODS

A total of 8351 non-cardiac surgical patients at high risk of cardiovascular complications were randomized to β-blocker or placebo. Neuraxial block was defined as spinal, lumbar or thoracic epidural anaesthesia. Logistic regression, with weighting using estimated propensity scores, was used to determine the association between neuraxial block and primary and secondary outcomes.

RESULTS

Neuraxial block was associated with an increased risk of the primary outcome [287 (7.3%) vs 229 (5.7%); odds ratio (OR), 1.24; 95% confidence interval (CI), 1.02-1.49; P=0.03] and MI [230 (5.9%) vs 177 (4.4%); OR, 1.32; 95% CI, 1.07-1.64; P=0.009] but not stroke [23 (0.6%) vs 32 (0.8%); OR, 0.76; 95% CI, 0.44-1.33; P=0.34], death [96 (2.5%) vs 111 (2.8%); OR, 0.87; 95% CI, 0.65-1.17; P=0.37] or clinically significant hypotension [522 (13.4%) vs 484 (12.1%); OR, 1.13; 95% CI, 0.99-1.30; P=0.08]. Thoracic epidural with general anaesthesia was associated with a worse primary outcome than general anaesthesia alone [86 (12.1%) vs 119 (5.4%); OR, 2.95; 95% CI, 2.00-4.35; P<0.001].

CONCLUSIONS

In patients at high risk of cardiovascular morbidity, neuraxial block was associated with an increased risk of adverse cardiovascular outcomes, which could be causal or because of residual confounding.