Diffusion-weighted imaging (DWI), together with computed tomography (CT), plays a crucial role in the diagnosis of acute cerebral infarction. The area that shows high signal intensity on DWI is considered to be the area of acute ischemia; the distribution, extent, and degree of this area provide important information for the selection of a therapeutic strategy.

However, the extent and degree of the hyperintense regions are highly dependent on window width (WW) and window level (WL) settings of the displayed or printed images. Physicians aware of this fact may arrive at the correct diagnosis by appropriately manipulating the window settings. However, in case this process of manipulation is bypassed or when the image printed on a film with improper window settings is interpreted, the physician may make an erroneous diagnosis and improper thrombolytic therapy with hemorrhagic complication.

ASIST-Japan proposes a novel and simple method to normalize DWI by changing its WW and WL settings by evaluating the T2-weighted image (T2WI) that is obtained simultaneously with the zero b-value. That is,

We are now conducting a multi-institutional trial to confirm that this method minimizes variations in DWI interpretation among scanners, institutions, and readers within the clinical setting. This process is crucial for DWI to be adopted as a reliable diagnostic tool in future clinical trials of novel therapeutic modalities.