Dynamic T1 measurement using snapshot-FLASH MRI.
The application of an inversion-recovery snapshot FLASH (fast low-angled shot) imaging sequence to the dynamic measurement of monoexponential T1 relaxation was investigated. The effect of (a) a reduction in the overall sequence repetition time, and (b) an increase of the read-pulse flip angle, on the measurement of T1 was analyzed. The error in T1 introduced by these factors is calculated, and a fuller analysis that takes them into account is presented. Data from a phantom are used to confirm this analysis. The magnitude of the errors is illustrated by measuring myocardial T1 in patients with acute ischaemic heart disease during the injection of a bolus of the contrast medium gadobenate dimeglumine. Overall, there was a 10% difference between the T1 values when the approximate and exact solutions were used; this was statistically significant. However, the difference was on average 25% for patients with a high heart rate (because of the shorter sequence-repetition time) in areas of infarcted myocardium (because of the longer T1).
Jivan
A
A
Department of Radiology, University of Leicester, Leicester, LE1 5WW, United Kingdom.
Horsfield
M A
MA
Moody
A R
AR
Cherryman
G R
GR
D003287:Contrast Media; D005682:Gadolinium; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008536:Meglumine / Q000031:analogs & derivatives; D009203:Myocardial Infarction / Q000175:diagnosis; D009206:Myocardium / Q000473:pathology; D009942:Organometallic Compounds; D019047:Phantoms, Imaging
D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine; D005682:Gadolinium