The relationship between diffusion tensor imaging findings and cognitive outcomes following adult traumatic brain injury: A meta-analysis.

Cognitive impairments are common following a traumatic brain injury (TBI) and frequently result from white matter (WM) damage. This damage can be quantified using diffusion tensor imaging (DTI), which measures the directionality (fractional anisotropy: FA) and amount (mean diffusivity/apparent diffusion coefficient: MD/ADC) of water diffusion in WM, with high FA and low MD/ADC thought to indicate greater WM integrity. However, the relationship between DTI and cognitive outcomes is currently unclear. The data from 20 studies that examined the relationship between WM integrity (measured using DTI) and cognition (categorised into seven domains) following mild-severe adult TBI were meta-analysed. Overall, high FA and low MD/ADC in most brain regions was associated with better cognitive performance, with memory and attention most strongly related to DTI findings. Specifically, memory and/or attention were very strongly related to DTI findings in the corpus callosum, fornix, internal capsule, arcuate and uncinate fasciculi. However, most findings were based on single studies and therefore await replication. Larger-scale, longitudinal studies are now needed to determine the predictive utility of DTI.

Endoscopic-assisted probing for congenital nasolacrimal duct obstruction.

PURPOSE: To determine the success rate of initial probing in children with congenital nasolacrimal duct obstruction (CNLDO) at different ages using nasal endoscopy, and to identify the anatomical sites of blockage within the drainage system. METHODS: A total of 87 eyes from 67 consecutive children with CNLDO underwent endoscopic nasolacrimal duct (NLD) probing under general anaesthetic. Patients who had had previous probings were excluded from the study. Diagnosis was based on history of epiphora since birth or shortly after, and fluorescein dye disappearance test (FDDT). Cure was judged as complete or near-complete remission of symptoms and signs and a normal FDDT. RESULTS: The age range was 12-91 months (mean 32.3 months). The success rates of probing were: 100% (58/58) for atresia and stenosis at the lower NLD, 100% (13/13) for punctal stenosis, 55.6% (5/9) for functional epiphora, and 0% (0/7) for canalicular and upper NLD obstruction. Age was not found to significantly affect the outcome of probing, whereas site did. Obstruction at canalicular or upper NLD level became more common with increasing age. CONCLUSION: Probing of the nasolacrimal system using the endoscopic approach allows direct visualisation of the distal nasolacrimal duct, which facilitates diagnosis of the anomaly at this site. More complex proximal anomalies became increasingly prevalent in older children, which accounted for the poorer results with increasing age. Site of obstruction has a greater bearing on outcome than patient age.