Purpose To explore the influence of different spin-locking frequencies on T1ρ values based on a 3.0T MR system.Materials and Methods Thirty-eight healthy adult volunteers underwent cardiac magnetic resonance imaging at the First Affiliated Hospital of Anhui Medical University from July to September 2023.T1ρ mapping and short-axis cine imaging with steady-state free precession sequences were performed with 3.0T MR system.T1ρ mapping sequence in three short-axis slices with three spin-lock frequencies at the amplitude of 5 Hz,300 Hz,400 Hz,and 500 Hz was scanned,respectively.T1ρ relaxation times and myocardial fibrosis index were quantified for each slice and each myocardial segment,the difference in T1ρ of different spin-locking frequencies and myocardial fibrosis index was analyzed using one-way repeated-measures analysis of variance method.Results T1ρ of 5 Hz,300 Hz,400 Hz,and 500 Hz were(33.9±2.8)ms,(43.4±2.1)ms,(45.4±2.6)ms and(46.5±2.4)ms,respectively;and T1ρ values showed a significant progressive increase from the low spin-lock frequency to the high spin-lock frequency of the heart(300 Hz vs.400 Hz:P<0.001;300 Hz vs.500 Hz:P<0.001;400 Hz vs.500 Hz:P=0.043).In addition,the measured myocardial fibrosis index at 300 Hz,400 Hz and 500 Hz were(9.4±2.2)ms,(11.3±2.9)ms and(12.6±2.7)ms,respectively.Statistical analysis underscored significant variations among these measurements(300 Hz vs.400 Hz:P<0.001;300 Hz vs.500 Hz:P<0.001;400 Hz vs.500 Hz:P=0.033).Conclusion In this prospective study,myocardial T1ρ values for the specific cardiac magnetic resonance setting are provided,and we found that spin-lock frequency can affect the T1ρ values.
MyocardiumMyocardial fibrosisMagnetic resonance imagingT1ρ mappingSpin-lock frequency