These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: [Optimization of numerical measurement parameters for ECG-triggered MRI snapshot-FLASH myocardial perfusion studies].
    Author: Nägele T, Miller S, Klose U, Brechtel K, Hahn U, Schick F, Stauder N, Nüsslin F.
    Journal: Rofo; 1999 Jan; 170(1):89-93. PubMed ID: 10071651.
    Abstract:
    BACKGROUND AND AIMS: In MR examinations of myocardial perfusion by the use of Snapshot-FLASH sequences it is of major importance that the achievable signal difference between pre- and normal postcontrast myocardium be maximized. METHODS: In ECG-triggered Snapshot-FLASH sequences the signal intensity of the myocardium depends on the flip angle alpha, the inversion time TI and the trigger delay TD (both depending on the cardiac frequency f) for unchanged slice thickness (SL), matrix size (MA), repetition time (TR) and echo time (TE). Therefore a simulation of the signal behavior of pre- and postcontrast myocardium based on Bloch's equations was performed by varying the flip angle alpha, TI and TD for different cardiac frequencies in order to determine an optimized combination of the measurement parameters. RESULTS: In normal heart rates (50-70 beats/min) maximal signal differences between pre- and normal postcontrast myocardium can be reached for inversion times TI = 170-200 ms and a flip angle alpha = 11 degrees. For higher heart rates again alpha = 11 degrees and TI = 200-220 ms with shortened TD (TD = 0 for f > 90 beats/min) were found to be optimal. The calculated values were semiquantitatively confirmed in phantom and volunteer measurements. CONCLUSIONS: The described method allows cardiac frequency dependent optimization of the Snapshot-FLASH measurement parameters alpha, TI and TD in order to reach a maximum in signal contrast between normal and malperfused myocardium.
    [Abstract] [Full Text] [Related] [New Search]