In many cases the complex geometry of objects makes it undesirable or even impossible to define a suitable region-of-interest manually. For certain types of analyses, if and where objects touch the outside of the volume of interest needs to be taken into account. The ROI shrink-wrap and primitive ROI plug-ins are powerful tools for automatic ROI definition in such cases. Especially when trying to analyze larger numbers of samples in a consistent manner this proves essential.
ROI shrink-wrap
The ROI shrink-wrap plug-in gives the possibility to automatically generate a region-of-interest by adapting to the shape of selected objects. It has three modes: shrink-wrap, fill-out and adaptive; these modes have additional options allowing to stretch over holes, remove pores or trim lumps. A description of the options along with practical examples can be found in ‘MN121 – ROI shrink-wrap’.

Binary image of a bone sample (left) and a region-of-interest automatically generated in CTAn using the shrink-wrap plug-in (right).