MR Perfusion Imaging

pletion of initial therapy, showing stable post-treatment changes or no significant focal accumulation of tracer on CT, will raise the likelihood of local control to nearly 100%. The corollary of this suggested scenario is that progressive imaging changes or focal tracer accumulation will indicate recurrence in about 75% or more of the cases in which those findings occur. With such high positive and negative predictive values, biopsy, with its attendant risks, should be performed only when confronted with a very high likelihood of recurrent tumor. This group will have been triaged on the basis of a pretreatment risk profile and objective posttreatment surveillance studies. This is not a plea for imaging all patients treated for head and neck cancer. Such a suggestion would be economically irresponsible. It is a plea for the logical and judicious application of powerful imaging tools to help improve the salvage rate and reduce the morbidity of treatment for recurrent head and neck squamous cell cancer. This will become more important as targeted nonsurgical salvage therapies become more widely available in the near future.