How can I differentiate between baseline(bl) and screening diagnosis (sc)?

Question

[marwa.cs91]

Hello all,

I downloaded ADNI dataset, Dataset format is .CSV then I convert them to plink format.

How can I differentiate between baseline(bl) and screening diagnosis (sc)?

For example: RID(295) is the same for bl and sc example:

RID  Phase  VISCODE
295   ADNI1  bl
295  ADNI1  m06
295  ADNI1  m12
295  ADNI1  m24
295  ADNI1  m36
295  ADNI1  m48

How can I identify Individuals as baseline diagnosis only in CSV files or in PED/MAP files