|High b value (DWI)||ADC map|
|Facilitated diffusion (e.g. benign cyst)|
|Restricted diffusion (e.g. malignant tumor)|
|Pitfalls of DWI|
|T2 – Shine through effect|
E.g. a cyst will demonstrate high signal intensity on T2-weighted images and on diffusion images obtained at high b values but also on the ADC map. Unlike a cyst, a region with truly restricted diffusion will demonstrate low signal intensity on the ADC map.
|Slow-flowing blood within a region may demonstrate the signal intensity characteristics of a highly cellular lesion. This pitfall is readily observed on DWI of a hemangioma. In this situation, interpretation of the findings obtained with other MR sequences is very helpful.|