I thought LSI was simply associated words of your keywords, that's all. Hope someone will correct me if I am wrong. I check my LSI words by using Google. search:~( keyword)
"LSI Optimization"** LSI is a technology (SVD), actually doing SEO and keyword research are a different process and approach altogether. LSI is considered to be an "old" technology, and while all the engines will do lexical/semantic analysis. LSI as such "ain't it." For those who haven't read up on the technology, there was a highly popular paper on it online that's been gone for a long time, and returns nothing but dead links. I happened to have a copy and since it's under a Creative Commons license, put it online to have it available again. Here's the lsi tutorial (what I could retrieve and salvage). It's really important to get somewhat of a grasp.