A system SY for determining a tissue type TY of a tissue region TR is provided in which the distal ends OFDE1..n of at least three optical fibers define a plurality of intersecting optical paths IOP1..k within the tissue region TR. A tissue signal Q1..k indicative of a tissue type TY for the respective optical path IOP1..k is generated from said spectral measurement data SMD corresponding to each of the plurality of intersecting optical paths IOP1..k. Each tissue signal Q1..k is compared with a reference threshold QRT for the tissue type, and with an average of the tissue signals QMA. At least a portion of the tissue region is identified as the tissue type TY if i) every tissue signal Q1..k in the tissue region TR indicates that its corresponding tissue is not the tissue type TY in the comparison with the reference threshold QRT and ii) at least one of the tissue signals Q1..k in the tissue region TR lies between the average QMA of the tissue signals Q1..k and the reference threshold QRT, and a difference Δ between the at least one tissue signal Q1..k and the average QMA of the tissue signals Q1..k exceeds a predetermined value ΔP.