Temporal response of T2 and adiabatic T1ρ and T2ρ relaxation times to acute ischemic injury to the femoral head: an in vivo piglet model study

Motivation: Relaxation time mapping may be clinically useful to inform the severity of ischemic injury to bone marrow in osteonecrosis of the femoral head. Goal(s): To compare the temporal response of T2, adiabatic T1ρ, and adiabatic T2ρ mapping to acute ischemic injury to the femoral head. Approach: 24 piglets were imaged using 3D relaxation time mapping at 3T MRI before and after surgical induction of unilateral femoral head ischemia. Corresponding cellular changes were evaluated histologically. Results: T2 and adiabatic T2ρ were the most sensitive in detecting acute injury to the femoral head, as early as 24 hours after onset of ischemia. Impact: T2 and/or adiabatic T2ρ relaxation time mapping can potentially address a clinical need for a non-contrast-enhanced imaging technique to establish the severity and extent of bone marrow necrosis in the earliest stages of osteonecrosis of the femoral head.