The emerging cyberinfrastructure holds the promise to provide on-demand access to high performance network resources, computing resources, and data storage/retrieval resources from anywhere similar to what the current electrical grid provides. Image guided neurosurgery is one of many applications that needs such on-demand access to resources. In this paper we have studied the feasibility of accessing high performance compute resources on-demand. An experiment was designed and carried out across seven TeraGrid resource sites for this feasibility study. This paper describes the experiment, provides an anlysis of the results and draws some conclusion regarding feasibility of on-demand access to high performance resources as it applies for this neurosurgery application. The grid provides scientific and commercial applications with access to high end resources, which are not generally available at many sites. While some jobs demand high throughput, some other jobs may demand quick respons...