Bone marrow burden score

The bone marrow burden score, also known as BMB-score, is a semi-quantitative MRI scoring system for assessing the extent of bone marrow involvement in Gaucher disease ¹. It was presented as an alternative for the quantitative Dixon quantitative chemical shift imaging (QCSI or fat fraction measurement) which is not available on every machine. 

Scoring system

The BMB-score is scored on sagittal T1 and T2 images of the lumbar spine and coronal T1 and T2 images of the femurs. A higher total BMB-score indicates more severe bone marrow involvement.

Lumbar spine

MRI signal intensity

• T1: vertebral bodies relative to nondiseased intervertebral discs
  • 0 = slightly hyperintense
  • 1 = isointense
  • 2 = slightly hypointense
  • 3 = hypointense
• T2: vertebral bodies relative to presacral fat 
  • 2 = hyperintense
  • 1 = slightly hyperintense
  • 0 = isointense
  • 1 = slightly hypointense
  • 2 = hypointense

Infiltration pattern

• 1 = patchy
• 2 = diffuse
• 1 = absence of fat in basivertebral vein region

Femora

MRI signal intensity

• T1: femur relative to subcutaneous fat
  • 0 = slightly hyperintense or isointense
  • 1 = slightly hypointense
  • 2 = hypointense
• T2: femur relative to subcutaneous fat
  • 2 = hyperintense
  • 1 = slightly hyperintense
  • 0 = isointense
  • 1 = slightly hypointense
  • 2 = hypointense
  • 3 = mixed type

Sites of involvement

• 1 = diaphysis
• 2 = proximal epiphysis/apophysis
• 3 = distal epiphysis

Related pathology

• Gaucher disease