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 and evaluation of reference region variable flip angle (RR-VFA) B1+ and T1 Mapping in the Prostate at 3T.
    Author: Rangwala NA, Dregely I, Wu HH, Sung K.
    Journal: J Magn Reson Imaging; 2017 Mar; 45(3):751-760. PubMed ID: 27532669.
    Abstract:
    PURPOSE: To optimize and evaluate the reference region variable flip angle (RR-VFA) technique for simultaneous B1+ and T1 mapping of the prostate at 3 Tesla (T). MATERIALS AND METHODS: The fat region surrounding the prostate was first identified using a fractional fat segmentation constant (tF ) and a signal fat-fraction threshold (rF ), and the relative flip angle (FA) was characterized using an effective fat T1 (T1f ) within the fat region. Optimal values of tF , rF , and T1f were chosen by comparing relative FA maps using RR-VFA (ARR-VFA ) with a reference relative FA maps (AREF ) in the surrounding fat and evaluating interpolation errors within the prostate. The optimized RR-VFA was evaluated in volunteers at 3T on a single scanner (n = 10) and across three scanners (n = 4). RESULTS: tF , rF and T1f were optimized as 0.5, 90%, and 320 ms, respectively. Prostate ARR-VFA showed differences of 30% among volunteers on one scanner, with no significant differences between ARR-VFA and AREF (P = 0.41). Prostate T1 after B1+ correction was 1998 ± 113 ms with significantly (P = 0.004) lower standard deviation than T1 before B1+ correction. The average coefficient of variation of prostate T1 across multiple scanners decreased from 15% to 5% after B1+ correction. CONCLUSION: The optimized RR-VFA can simultaneously measure B1+ and T1 in the prostate without the need for an additional scan and improve T1 consistency within and across MRI scanners at 3T. LEVEL OF EVIDENCE: 3 J. Magn. Reson. Imaging 2017;45:751-760.
    [Abstract] [Full Text] [Related] [New Search]