I guess that struct is a variable you created, that struct is a cell array, that struct{4,1} is the character vector 'Florbela', that struct{4,2} is the character vector 'Lopes', and that struct{4,3} is the character vector 'Ferreiro'.
You shouldn't name a variable "struct" because that conflicts with the built-in MATLAB function "struct". You won't be able to use the function "struct" as long as the variable "struct" is in the workspace. So I'll call it "S". Maybe it looks like this:
S = {'Some';'Other';'Name';'Florbela';'Lopes';'Ferreiro'}
If you want spaces between the words, you can do this:
A.PatientName = [S{4,1}, ' ', S{5,1}, ' ', S{6,1}]
or this:
A.PatientName = sprintf('%s %s %s',S{4:6,1})
