Clean Cut (adaptive, multimodal surgical infection prevention programme) for low-resource settings: a prospective quality improvement study.

BACKGROUND: Clean Cut is an adaptive, multimodal programme to identify improvement opportunities and safety changes in surgery by enhancing outcomes surveillance, closing gaps in surgical infection prevention standards, and strengthening underlying processes of care. Surgical-site infections (SSIs) are common in low-income countries, so this study assessed a simple intervention to improve perioperative infection prevention practices in one. METHODS: Clean Cut was implemented in five hospitals in Ethiopia from August 2016 to October 2018. Compliance data were collected from the operating room focused on six key perioperative infection prevention standards. Process-mapping exercises were employed to understand barriers to compliance and identify locally driven improvement opportunities. Thirty-day outcomes were recorded on patients for whom intraoperative compliance information had been collected. RESULTS: Compliance data were collected from 2213 operations (374 at baseline and 1839 following process improvements) in 2202 patients. Follow-up was completed in 2159 patients (98·0 per cent). At baseline, perioperative teams complied with a mean of only 2·9 of the six critical perioperative infection prevention standards; following process improvement changes, compliance rose to a mean of 4·5 (P < 0·001). The relative risk of surgical infections after Clean Cut implementation was 0·65 (95 per cent c.i. 0·43 to 0·99; P = 0·043). Improved compliance with standards reduced the risk of postoperative infection by 46 per cent (relative risk 0·54, 95 per cent c.i. 0·30 to 0·97, for adherence score 3-6 versus 0-2; P = 0·038). CONCLUSION: The Clean Cut programme improved infection prevention standards to reduce SSI without infrastructure expenses or resource investments.

GABA spectra and remote distractor effect in progressive supranuclear palsy: A pilot study.

Disturbances of the gamma-aminobutyric-acid (GABA) system have been suspected of contributing to the pathophysiology of progressive supranuclear palsy (PSP). The ability to rapidly resolve competitive action decisions, such as shifting the gaze to one particular stimulus rather than another, can be predicted by the concentration of GABA in the region of the frontal cortex relevant to eye movements. For this reason, our study measured GABA levels in seven PSP patients and eight healthy controls, using proton magnetic resonance spectroscopy, and assessed the relationship of these measurements to the remote distractor effect (RDE), an eye-movement paradigm investigating competitive action decisions. No significant differences were found in either frontal-eye-field GABA levels or RDE between PSP patients and controls.

The age dependence of T2 relaxation times of N-acetyl aspartate, creatine and choline in the human brain at 3 and 4T.

Knowledge of the T2 age dependence is of importance for MRS clinical studies involving subject groups with a wide age range. A number of studies have focused on the age dependence of T2 values in the human brain, with rather conflicting results. The aim of this study was to analyze the age dependence of T2 values of N-acetyl aspartate (NAA), creatine (Cr) and choline (Cho) in the human brain using data acquired at 3T and 4T and to assess the influence of the macromolecule (MM) baseline handling on the obtained results. Two distinct groups of young and elderly controls have been measured at 3T (TE = 30-540 ms, 9 young and 11 elderly subjects) and 4T (TE = 10-180 ms, 18 young and 14 elderly subjects) using single-voxel spectroscopy. In addition, MM spectra were measured from two subjects using the inversion-recovery technique at 4T. All spectra were processed with LCModel using basis sets with different MM signals (measured or simulated) and also with MM signals included for a different TE range. Individual estimated T2 values were statistically analyzed using the R programming language for the age dependence of T2 values as well as the influence of the MM baseline handling. A significant decrease of T2 values of NAA and Cr in elderly subjects compared with young subjects was confirmed. The same trend was observed for Cho. Significantly higher T2 values calculated using the measured MM baseline for all studied metabolites at 4T were observed for both young and elderly subjects. To conclude, while the handling of MM and lipid signals may have a significant effect on estimated T2 values, we confirmed the age dependence of T2 values of NAA and Cr and the same trend for Cho in the human brain. Copyright © 2016 John Wiley & Sons, Ltd.

Minipig model of Huntington's disease: ¹H magnetic resonance spectroscopy of the brain.

Huntington's disease (HD) is an inherited autosomal neurodegenerative disorder affecting predominantly the brain, characterized by motor dysfunctions, behavioral and cognitive disturbances. The aim of this study was to determine changes in the brain of transgenic minipigs before HD onset using (1)H magnetic resonance (MR) spectroscopy. Measurements were performed on a 3 T MR scanner using a single voxel spectroscopy sequence for spectra acquisition in the white matter and chemical shift imaging sequence for measurement in the striatum, hippocampus and thalamus. A decrease of (phospho)creatine (tCr) concentration was found only in the thalamus (p=0.002) of transgenic minipigs, nevertheless we found significant changes in metabolite ratios. Increase of the ratio choline compounds (tCho)/tCr was found in all examined areas: striatum (p=0.010), thalamus (p=0.011) as well as hippocampus (p=0.027). The ratio N-acetylaspartate+N-acetylaspartylglutamate (tNAA)/tCr (p=0.043) and glutamate+glutamine (Glx)/tCr (p=0.039) was elevated in the thalamus, the ratio myo-inositol (Ins)/tCr (p=0.048) was significantly increased in the hippocampus. No significant differences were observed in the metabolite concentrations in the white matter, however we found significant increase of ratios tNAA/tCr (p=0.018) and tCho/tCr (p=0.003) ratios in transgenic boars. We suppose that the majority of the observed changes are predominantly related to changes in energy metabolism caused by decrease of tCr.

The relationships between quantitative MR parameters in hippocampus in healthy subjects and patients with temporal lobe epilepsy.

We introduce a new magnetic resonance (MR) method based on a pixel-by-pixel image processing to examine relationships between metabolic and structural processes in the pathologic hippocampus. The method was tested for lateralization of the epileptogenic zone in patients with temporal lobe epilepsy (TLE). Twenty patients with drug-resistant TLE and fifteen healthy controls were examined at 3T. The measurement protocol contained T2-weighted MR images, spectroscopic imaging, diffusion tensor imaging and T2 relaxometry. Correlations between quantitative MR parameters were calculated on a pixel-by-pixel basis using the CORIMA program which enables automated pixel identification in the normal tissue according to control data. All MR parameters changed in the anteroposterior direction in the hippocampus and correlation patterns and their slopes differed between patients and controls. Combinations of T2 relaxation times with metabolite values represent the best biomarkers of the epileptogenic zone. Correlations with mean diffusivity did not provide sufficiently accurate results due to diffusion image distortions. Quantitative MR analysis non-invasively provides a detailed description of hippocampal pathology and may represent complementary tool to the standard clinical protocol. However, the automated processing should be carefully monitored in order to avoid possible errors caused by MR artifacts.

Fast 3D radiofrequency field mapping using echo-planar imaging.

An inhomogeneous radiofrequency (RF) magnetic field is an essential source of error for the quantification of MRI and MRS parameters. To correct for effects of RF inhomogeneities in 3D data sets, it is necessary to have knowledge of the 3D RF distribution in the sample. In this paper a method for fast 3D RF mapping is presented. The method is based on the simultaneous acquisition of a spin echo (SE) and a stimulated echo (STE) using echo-planar imaging (EPI). The acquisition of the 3D RF map using 64 partitions and TR = 500 ms requires 1.5 min. The use of the sequence in vivo is demonstrated by the calculation of the RF maps in the human brain at 3T. The comparison of calculated flip angles with the flip angles obtained by fitting signal behavior in the 3D stimulated-echo acquisition mode (STEAM)-EPI sequence and the analysis of errors due to spatially dependent T(1) values in the brain show that the accuracy of the calculated flip angles in the human brain is about 2 degrees.

Error images for spectroscopic imaging by LCModel using Cramer-Rao bounds.

The results of spectroscopic imaging (SI) measurements are often presented as metabolic images. If the spectra quality is not sufficient, the calculated concentrations are biased and the metabolic images show an incorrect metabolite distribution. To simplify the quality analysis of spectra measured by SI, an error image, reflecting the accuracy of the computed concentrations, can be displayed along with the metabolite image. In this paper the relevance of Cramer-Rao bounds (CRBs) calculated by the LCModel program to describe errors in estimated concentrations is validated using spectra simulations. The relation between the average CRBs and standard deviations (STD) of metabolite concentrations from 100 simulated spectra for various signal to noise ratio and line broadening conditions is evaluated. A parameter for calculating error images for metabolite ratios is proposed and an effective way to display error images is shown. The results suggest that the average CRBs are strongly correlated with the standard deviations and hence that CRB values reflect the relative uncertainty of the calculated concentrations. The error information can be integrated directly into a metabolite image by displaying only those areas of the metabolite image with corresponding CRBs below a selected threshold or by mapping CRBs as a transparency of the metabolite image. The concept of error images avoids extensive examination of each SI spectrum and helps to reject low quality spectra.