TY - JOUR
T1 - Towards measuring the effect of flow in blood T-1 assessed in a flow phantom and in vivo
AU - Hermann, Ingo
AU - Uhrig, Tanja
AU - Chacon-Caldera, Jorge
AU - Akcakaya, Mehmet
AU - Schad, Lothar R.
AU - Weingartner, Sebastian
PY - 2020
Y1 - 2020
N2 - Measurement of the bloodT1time using conventional myocardialT1mapping methods hasgained clinical significance in the context of extracellular volume (ECV) mapping and synthetichematocrit (Hct). However, its accuracy is potentially compromised by in-flow ofnon-inverted/non-saturated spins and in-flow of spins which are not partially saturated fromprevious imaging pulses.Bloch simulations were used to analyze various flow effects separately.T1measurements ofgadolinium doped water were performed using a flow phantom with adjustable flow velocities at3 T. Additionally,in vivobloodT1measurements were performed in 6 healthy subjects (26±5years, 2 female). To study theT1time as a function of the instantaneous flow velocity,T1timeswere evaluated in an axial imaging slice of the descending aorta. Velocity encoded cinemeasurements were performed to quantify the flow velocity throughout the cardiac cycle.Simulation results show more than 30% loss in accuracy for 10% non-prepared in-flowingspins. However, in- and out-flow to the imaging plane only demonstrated minor impact on theT1time. PhantomT1times were decreased by up to 200 ms in the flow phantom, due to in-flow ofnon-preparedspins.Highflowvelocitiescausein-flowofspinsthatlackpartialsaturationfromtheimaging pulses but only lead to negligibleT1time deviation (less than 30 ms).In vivomeasurements confirm a substantial variation of theT1time depending on the flow velocity. Thehighest aorticT1times are observed at the time point of minimal flow with increased flow velocityleading to reduction of the measuredT1time by up to130±49 ms at peak velocity.In this work we attempt to dissect the effects of flow onT1times, by using simulations,well-controlled, simplified phantom setup and the linear flow pattern in the descending aortain vivo.
AB - Measurement of the bloodT1time using conventional myocardialT1mapping methods hasgained clinical significance in the context of extracellular volume (ECV) mapping and synthetichematocrit (Hct). However, its accuracy is potentially compromised by in-flow ofnon-inverted/non-saturated spins and in-flow of spins which are not partially saturated fromprevious imaging pulses.Bloch simulations were used to analyze various flow effects separately.T1measurements ofgadolinium doped water were performed using a flow phantom with adjustable flow velocities at3 T. Additionally,in vivobloodT1measurements were performed in 6 healthy subjects (26±5years, 2 female). To study theT1time as a function of the instantaneous flow velocity,T1timeswere evaluated in an axial imaging slice of the descending aorta. Velocity encoded cinemeasurements were performed to quantify the flow velocity throughout the cardiac cycle.Simulation results show more than 30% loss in accuracy for 10% non-prepared in-flowingspins. However, in- and out-flow to the imaging plane only demonstrated minor impact on theT1time. PhantomT1times were decreased by up to 200 ms in the flow phantom, due to in-flow ofnon-preparedspins.Highflowvelocitiescausein-flowofspinsthatlackpartialsaturationfromtheimaging pulses but only lead to negligibleT1time deviation (less than 30 ms).In vivomeasurements confirm a substantial variation of theT1time depending on the flow velocity. Thehighest aorticT1times are observed at the time point of minimal flow with increased flow velocityleading to reduction of the measuredT1time by up to130±49 ms at peak velocity.In this work we attempt to dissect the effects of flow onT1times, by using simulations,well-controlled, simplified phantom setup and the linear flow pattern in the descending aortain vivo.
KW - cardiac T-1 mapping
KW - flow velocity dependency
KW - flow phantom
KW - blood T-1
UR - http://www.scopus.com/inward/record.url?scp=85086384780&partnerID=8YFLogxK
U2 - 10.1088/1361-6560/ab7ef1
DO - 10.1088/1361-6560/ab7ef1
M3 - Article
SN - 0031-9155
VL - 65
JO - Physics in Medicine and Biology
JF - Physics in Medicine and Biology
IS - 9
M1 - 095001
ER -