Teleradiology and emerging business models.

A number of new diagnostic radiology services have emerged which use teleradiology. The main themes include: (1) stand-alone teleradiology practice; (2) the "Nighthawk"/on-call coverage; (3) solo radiologist practice; (4) expert/second-opinion teleradiology; (5) a global virtual radiology service based on workload sharing and reallocation. More applications of teleradiology can be expected due to the continuing shortages and uneven distribution of radiologists, and the increasing use of radiological imaging for diagnosis. In a large enterprise, such as the US army, teleradiology will allow the creation of a global diagnostic organization where diagnostic images are distributed according to the availability of radiologists. Eventually the distinction between picture archiving and communication systems and teleradiology will be blurred and radiology will be provided by virtual organizations with distributed capabilities. As teleradiology services claim a bigger share of radiology practice, various legal and regulatory issues will need to be solved. Ultimately the successful business model will depend on the ability to produce the highest-quality product at the lowest cost.

Functional magnetic resonance imaging reflects changes in brain functioning with sedation.

Functional magnetic resonance imaging (fMRI) studies have demonstrated localized brain activation during cognitive tasks. Brain activation increases with task complexity and decreases with familiarity. This study investigates how sleepiness alters the relationship between brain activation and task familiarity. We hypothesize that sleepiness prevents the reduction in activation associated with practice. Twenty-nine individuals rated their sleepiness using the Stanford Sleepiness Scale before fMRI. During imaging, subjects performed the Paced Auditory Serial Addition Test, a continuous mental arithmetic task. A positive correlation was observed between self-rated sleepiness and frontal brain activation. Fourteen subjects participated in phase 2. Sleepiness was induced by evening dosing with chlorpheniramine (CP) (8 mg or 12 mg) and terfenadine (60 mg) in the morning for 3 days before the second fMRI scan. The Multiple Sleep Latency Test (MSLT) was also performed. Results revealed a significant increase in fMRI activation in proportion to the dose of CP. In contrast, for all subjects receiving placebo there was a reduction in brain activation. MSLT revealed significant daytime sleepiness for subjects receiving CP. These findings suggest that sleepiness interferes with efficiency of brain functioning. The sleepy or sedated brain shows increased oxygen utilization during performance of a familiar cognitive task. Thus, the beneficial effect of prior task exposure is lost under conditions of sedation. Copyright 2000 John Wiley & Sons, Ltd.