Protocols 

Whilst you can always reach out to us for any advice if collecting new data or setting up a study, below are a couple of protocols that can be used as guidance to create a pipeline for your own study.

MRI

Below you can find MRI protocols from 6 global studies/collaborations. These contain information pertaining to multiple scanner manufacturers and field strengths.

• Canadian Dementia Imaging Protocol
• Alzheimer’s Disease Neuroimaging Initiative (ADNI) 
• Mark Vascular Cognitive Impairment and Dementia (MarkVCID)
• Multi-Partner Consortium to Expand Dementia Research in Latin America (ReDLat)
• Open Access Series Of Imaging Studies (OASIS)
• UK Biobank

Blood collection to measure circulating cell free DNA

Blood collection:

• Whole blood can be collected in an EDTA tube and processed to isolate plasma, ideally within 2 hours of blood draw or as soon as possible and <24 hours. Store collected blood in EDTA tubes at 4°C after blood is drawn until plasma is isolated.
• If blood cannot be processed within 24 hours after blood draw or blood cannot be kept at 4°C until processing, it is recommended to use a blood collection tube with stabilizers for cell-free DNA collection. Examples include:
  • • Cell-Free DNA BCT® RUO (Streck)
    • Cell-Free DNA Collection Tube (Roche)
    • CellSave Preservative Tubes (Janssen Diagnostic)
    • PAXgene Blood ccfDNA Tube (Qiagen)
    • cf-DNA/cf-RNA Preservative Tubes (Norgen Biotek Corp)
      These tubes will keep blood stable at room temperature for up to 7 days after blood draw, allowing for transport or delayed processing.

To isolate plasma, we recommend a two-step centrifugation*:

1. Centrifuge whole blood tubes at 800-2000g for 10 minutes
2. Carefully transfer the supernatant to a fresh, labeled 15 mL tube
3. Centrifuge the 15mL tube with supernatant at 12,000-16,000 g for 10 minutes.
4. Immediately after centrifuge, carefully transfer plasma supernatant into 1mL or 2mL aliquots (though a pellet may not be visible, avoid jostling the tube or drawing fluid from the bottom of the tube).
5. Store aliquots at -80°C until further processing or proceed directly to cell free DNA extraction

* Cell free DNA yield and quality is quite consistent across centrifugation protocols for 1 or 2 step centrifugation, centrifugation speeds, and whether cells are centrifuged at room temperature or 4°C. Thus, this centrifugation protocol is a guideline.

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