Branching pattern of diatal MCA.
(A) The branching pattern of distal middle cerebral artery (MCA) modified from Cai H et al. (Stroke 1998;29:1982–1987). (B)-(E) Examples of distal middle cerebral artery (MCA) pattern (B, Type 1; C, Type 3; D, Type 6; E, 2MCAs) are presented. (F)-(H) In 2 SP.MES rats, we found extremely atypical distal MCA (named as Type X). When the distal MCA was occluded in a routine manner (F), blood flow was maintained through an aberrant vessel (arrow). In the second case, however, we could block this aberrant blood flow (X) by placing the laser beam at 2 separate points (H). (I) Fenestration of distal MCA in a SP.MES rat. We excluded atypical distal MCAs (E-I, i.e., 2MCAs, Type X, and fenestration) from the analysis.