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Question Posted 05/06/14:
Hi, I am working on MR images. I have identified patients converted from MCI to AD. I have also collected the available data of those patients. But how to know which data are of MCI stage and which are after conversion?
Response posted 05/06/14 by Jessica Yaros, IDA:
The Diagnosis Summary dataset, available to ADNI investigators, captures the subject diagnosis at each visit and flags whether there has been a diagnosis conversion or reversion.

Since you can see on which visits the conversions took place, you can compare images from before and after the conversion date.
Response posted 05/06/14 by S Ray:
Thank you sir. I have gone through the Diagnosis Summery database. There are some problems -
1. Headers are not readily understandable. Where can I get the details of all acronyms used in different .csv files?
2. DXCONV, possibly the conversion information from one stage to another, is not given for ADNIGO/2
3. As per data dictionary RID 223 was converted to NL to MCI, but in Diagnosis Summery table at line 507 as well as at 3240 DXCONV=1. What does it mean?
4. for RID 843, at line no. 3093 in Diagnosis Summery dataset, DXCONV=1, EXAMDATE=15-01-09. but after collecting the complete imgae data of that patient in the list there is no image of the same date. the nearest date is 21-01-09. Now how to decide the exact data? Where is the mismatch?
Response posted 05/08/14 by Jessica Yaros, IDA:
1. All Column names are defined in the Data Dictionary, which is located in the Study Info category. You could also use the online data dictionary search at http://adni.loni.usc.edu/support/

ADNI1 and ADNIGO/2 collected diagnosis summary information differently, so the Diagnostic Summary table is actually a combination of two tables (PDXCONV and DXSUM). To find definitions of the fields for records listed as ADNI1, look in the ADNI Data Dictionary for the table PDXCONV. Alternatively, the fields for subjects listed as ADNI2 are defined under the table DXSUM. You will notice that records for subjects with data collected from ADNI1 will not have data in fields associated with ADNIGO/2 and vice versa.

2. For example, ADNI1 conversion information is under the DXCURREN and DXCONV columns, but the ADNIGO/2 conversion info is under the DXCHANGE column instead.

3. What you are seeing with RID 223 at line 507 is the conversion (represented by DXCONV =1) to MCI (represented by DXCURREN = 2). Then at line 3240 the same subject has another conversion (again, DXCONV = 1) to AD (DXCURRENT=3). This is more obvious to see if you sort the table by RID.

4. Subjects do not have scans on every exam date. Conversions are based on subject performance on assessments and clinical recommendations.
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