Clot Burden Score (CBS)

David Goldemund M.D.
Updated on 21/04/2024, published on 20/12/2022
  • the extent of intracranial thrombosis predicts clinical outcome, final infarct size, and risk of hemorrhagic transformation in acute ischemic stroke
    • clots with proximal localization and increased length are more difficult to treat and have a worse outcome
  • Clot Burden Score (CBS) is a semiquantitative, CTA-based score that defines the extent of thrombosis in the anterior circulation 
  • 10 points are assigned for a normal CTA
    • 2 points are subtracted for thrombus in the proximal M1, distal M1, or supraclinoid ICA portion
    • 1 point is subtracted for thrombus in M2 branches, A1, and/or infraclinoid ICA portion
  • the recanalization rate is higher with intravenous tPA in patients with a CBS > 6  [Demchuk, 2009]
  • a lower CBS is associated with:
    • lower ASPECTS [Puetz, 2008]
    • higher rates of parenchymal hematoma  [Puetz, 2008]
    • decreased odds of favorable functional outcome
      • odds ratio 0.09 for CBS ≤ 5, 0.22 for CBS 6-7, and 0.48 for CBS 8-9 [Puetz, 2008]
      • the association between the CBS and functional outcome varies for different collateral scores (Derraz, 2021)
  • CBS can also be assessed on FLAIR, MRA, or MR-GRE (T2*CBSCBS 9 on MR GRE  [Derraz, 2019]  
    • susceptibility vessel sign (SVS)
      • diameter and length (thrombus length tends to be smaller in those with early reperfusion)
      • S-shaped or A-shaped
    • clot intensity on FLAIR
      • high FLAIR clot intensity may predict successful reperfusion (Fujimoto, 2015)
infraclinoid portion of ICA – 1
supraclinoid portion of ICA
– 2
proximal M1 segment
– 2
distal M1 segment
– 2
M2 branch
– 1
M2 branch
– 1
ACA – 1
Clot burden scale (CBS)
Clot Burden Score - CBS (Tan, AJNR 2009)
T-occlusion (ICA, MCA, ACA) - Clot Burden Score 5

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Clot Burden Score (CBS)