The significance of streamlined postprocessing approaches for clinical FMRI.

T he article in this issue of the American Journal of Neuroradiol-ogy (AJNR) entitled " Simple fMRI Postprocessing Suffices for Normal Clinical Practice " 1 is an important contribution to the current blood oxygen level– dependent (BOLD) fMRI literature because it highlights an emerging trend in functional neuroimag-ing software development that will likely promote increasing clinical use of fMRI in the near future. Although many attempts have been made during the past decade to standardize fMRI paradigms across institutions, streamline BOLD fMRI preprocessing and postprocessing, validate fMRI by using intraoperative electro-physiologic criterion standards, and establish standards for fMRI image acquisition, processing, and interpretation, only some of these have been reasonably successful. 2-4 The greatest strength of the BOLD fMRI technique—its immense versatility with respect to assessment of cognitive networks, paradigm design, and signal-processing approaches— has also proved to be its greatest weakness from a clinical standardization standpoint. Presurgical planning for resectable brain lesions was the original clinical application of BOLD fMRI and remains the sole widely accepted clinical application (if we consider the broader category of pretherapeutic planning, including planning for radiation therapy and hemispheric language lateralization for epilepsy) for which Current Procedural Terminology codes were established in 2007. 5 Currently, expansion of clinical indications to include posttherapeutic monitoring of eloquent cortex has also been accepted. In a nutshell, clinical functional MR imaging enables neuroradiologists to go beyond mere characterization of anatomic findings and instead provide critical functional-ana-tomic correlation that is essential for accurate assessment of the risks of neurosurgical or radiation treatment. The relatively cumbersome nature of research-level BOLD fMRI postprocessing software (which typically requires graduate-level experience in image processing, including computer programming within environments such as Matlab [MathWorks, Natick, Massachusetts] for generation of custom-made scripts for semiautomated execution of multiple processing steps for clinical applications) has been a limitation recently overcome by more streamlined commercially available FDA-approved packages. These newer packages allow more user-friendly interaction; better image overlays, including interactive 3D viewing; and greater compatibility with PACS servers and neuronavigation software for facilitation of image export and viewing by referring physicians and patients alike. 6 These developments have led to the capability of importing functional images into the operating room in a fashion that neu-rosurgeons can easily use in planning their surgery. With brain shift occurring following violation of the dura, the original exact landmarks provided by the preoperative functional imaging may not be accurate. Overlays with postgadolinium …