The Utility of Ultrasound to Diagnose Tunnel-Tract Infection Related to Indwelling Pleural Catheters.

Indwelling pleural catheter (IPC) infections lead to increased morbidity and treatment failure in patients with chronic recurrent pleural effusions. Ultrasonography is a readily available diagnostic tool used by pulmonologists on a daily basis. Ultrasonography has been used to identify the etiology of indwelling peritoneal catheter obstruction, including infection of the exit site and tunnel tract. The use of ultrasonography to identify tunnel-tract infection involving IPC has not been reported. We describe the ultrasonographic characteristics of 3 cases of confirmed tunnel-tract infection and compared them with noninfected chronic IPCs. Ultrasonographic evaluation of the soft tissue tunnel tract can accurately identify fluid collections around the catheter and cuff, which is highly suggestive of tunnel-tract infection.

The less BOLD, the wiser: support for the latent resource hypothesis after traumatic brain injury.

Previous studies of the BOLD response in the injured brain have revealed neural recruitment relative to controls during working memory tasks in several brain regions, most consistently the right prefrontal cortex and anterior cingulate cortices. We previously proposed that the recruitment observed in this literature represents auxiliary support resources, and that recruitment of PFC is not abnormal or injury specific and should reduce as novelty and challenge decrease. The current study directly tests this hypothesis in the context of practice of a working memory task. It was hypothesized that individuals with brain injury would demonstrate recruitment of previously indicated regions, behavioral improvement following task practice, and a reduction in the BOLD signal in recruited regions after practice. Individuals with traumatic brain injury and healthy controls performed the n-back during fMRI acquisition, practiced each task out of the scanner, and returned to the scanner for additional fMRI n-back acquisition. Statistical parametric maps demonstrated a number of regions of recruitment in the 1-back in individuals with brain injury and a number of corresponding regions of reduced activation in individuals with brain injury following practice in both the 1-back and 2-back. Regions of interest demonstrated reduced activation following practice, including the anterior cingulate and right prefrontal cortices. Individuals with brain injury demonstrated modest behavioral improvements following practice. These findings suggest that neural recruitment in brain injury does not represent reorganization but a natural extension of latent mechanisms that engage transiently and are contingent upon cerebral challenge.

The nature of processing speed deficits in traumatic brain injury: is less brain more?

The cognitive constructs working memory (WM) and processing speed are fundamental components to general intellectual functioning in humans and highly susceptible to disruption following neurological insult. Much of the work to date examining speeded working memory deficits in clinical samples using functional imaging has demonstrated recruitment of network areas including prefrontal cortex (PFC) and anterior cingulate cortex (ACC). What remains unclear is the nature of this neural recruitment. The goal of this study was to isolate the neural networks distinct from those evident in healthy adults and to determine if reaction time (RT) reliably predicts observable between-group differences. The current data indicate that much of the neural recruitment in TBI during a speeded visual scanning task is positively correlated with RT. These data indicate that recruitment in PFC during tasks of rapid information processing are at least partially attributable to normal recruitment of PFC support resources during slowed task processing.