Expected headings
"CBV vs rCBV"
"The first can be corrected for by assessing only the first pass of contrast. The second is more problematic as permeability can vary dramatically. Due to this difficulty in most instances what is actually being calculated is CBV relative to an internal control (e.g. contralateral normal white matter or an arterial input function) 2. As such it is usually referred to as relative cerebral blood volume (rCBV) and has no units (since it is just a ratio)."