Cortical structural involvement and cognitive dysfunction in early Parkinson's disease.

Magnetic resonance imaging (MRI) studies in early Parkinson's disease (PD) have shown promise in the detection of disease-related brain changes in the white and deep grey matter. We set out to establish whether intrinsic cortical involvement in early PD can be detected with quantitative MRI. We collected a rich, multi-modal dataset, including diffusion MRI, T1 relaxometry and cortical morphometry, in 20 patients with early PD (disease duration, 1.9 ± 0.97 years, Hoehn & Yahr 1-2) and in 19 matched controls. The cortex was reconstructed using FreeSurfer. Data analysis employed linked independent component analysis (ICA), a novel data-driven technique that allows for data fusion and extraction of multi-modal components before further analysis. For comparison, we performed standard uni-modal analysis with a general linear model (GLM). Linked ICA detected multi-modal cortical changes in early PD (p = 0.015). These comprised fractional anisotropy reduction in dorsolateral prefrontal, cingulate and premotor cortex and the superior parietal lobule, mean diffusivity increase in the mesolimbic, somatosensory and superior parietal cortex, sparse diffusivity decrease in lateral parietal and right prefrontal cortex, and sparse changes to the cortex area. In PD, the amount of cortical dysintegrity correlated with diminished cognitive performance. Importantly, uni-modal analysis detected no significant group difference on any imaging modality. We detected microstructural cortical pathology in early PD using a data-driven, multi-modal approach. This pathology is correlated with diminished cognitive performance. Our results indicate that early degenerative processes leave an MRI signature in the cortex of patients with early PD. The cortical imaging findings are behaviourally meaningful and provide a link between cognitive status and microstructural cortical pathology in patients with early PD.

Partial volume correction of multiple inversion time arterial spin labeling MRI data.

The accuracy of cerebral blood flow (CBF) estimates from arterial spin labeling (ASL) is affected by the presence of both gray matter (GM) and white matter within any voxel. Recently a partial volume (PV) correction method for ASL has been demonstrated (Asllani et al. Magn Reson Med 2008; 60:1362-1371), where PV estimates were used with a local linear regression to separate the GM and white matter ASL signal. Here a new PV correction method for multi-inversion time ASL is proposed that exploits PV estimates within a spatially regularized kinetic curve model analysis. The proposed method exploits both PV estimates and the different kinetics of the ASL signal arising from GM and white matter. The new correction method is shown, on both simulated and real data, to provide correction of GM CBF comparable to a linear regression approach, whilst preserving greater spatial detail in the CBF image. On real data corrected GM CBF values were found to be largely independent of GM PV, implying that the correction had been successful. Increases of mean GM CBF after correction of 69-80% were observed.

Cica-Care gel sheeting in the management of hypertrophic scarring.

A prospective, controlled clinical trial was undertaken to assess the efficacy and safety of two types of silicone gel, Silastic Gel Sheeting (SGS) and Cica-Care (CC), in the management of hypertrophic scars. Forty-two patients were randomly assigned to SGS and CC groups and their hypertrophic scars were divided into treated and control areas. Extensometric measurements were made at monthly intervals for 6 months and significant improvement of the treated areas relative to the control areas was observed. The two gels were not significantly different in efficacy or safety, but CC, being more adhesive and more comfortable than SGS, has advantages in ease of use and patient acceptability.

Alginate dressing as a donor site haemostat.

An alginate fibre dressing has been used to reduce blood loss from skin graft donor sites. Significant haemostasis has been achieved in the immediate post surgery phase and no adverse reactions observed.

Silastic foam dressing: an appraisal.

Silastic foam polymerised in situ has been investigated as an alternative to other means of securely dressing split thickness skin grafts on involuted sites. The bacteriological risks and physical hazards have been explored. From a series of 25 patients silastic foam appeared to offer an easier safer and more effective means of graft fixation in difficult areas.