Cramer-Rao lower bounds for precision in T2* assessment for myocardial iron overload measurements by T2* multi-echo CMR
- PDF / 259,067 Bytes
- 2 Pages / 610 x 792 pts Page_size
- 49 Downloads / 186 Views
BioMed Central
Open Access
Poster presentation
Cramer-Rao lower bounds for precision in T2* assessment for myocardial iron overload measurements by T2* multi-echo CMR Vincenzo Positano*1, Antonella Meloni1, Alessia Pepe1, Maria Filomena Santarelli1, Daniele De Marchi1, Luca Menichetti1, Chiara Dell'Amico1, Brunella Favilli1, Matteo Milanesi1, Gianluca Valeri2, Luigi Natale3, Cristina Tassi4, Tommaso Casini5, Luigi Landini1 and Massimo Lombardi1 Address: 1"G Monasterio" Foundation and Institute of Clinical Physiology, CNR, Pisa, Italy, 2Ospedali Riuniti di Ancona, Ancona, Italy, 3Policlinico "Gemelli", Roma, Italy, 4Policlinico S. Orsola "L. e A. Seragnoli", Bologna, Italy and 5Ospedale Meyer, Firenze, Italy * Corresponding author
from 13th Annual SCMR Scientific Sessions Phoenix, AZ, USA. 21-24 January 2010 Published: 21 January 2010 Journal of Cardiovascular Magnetic Resonance 2010, 12(Suppl 1):P275
doi:10.1186/1532-429X-12-S1-P275
Abstracts of the 13th Annual SCMR Scientific Sessions - 2010
Meeting abstracts - A single PDF containing all abstracts in this Supplement is available here. http://www.biomedcentral.com/content/files/pdf/1532-429X-11-S1-infoThis abstract is available from: http://jcmr-online.com/content/12/S1/P275 © 2010 Positano et al; licensee BioMed Central Ltd.
Introduction T2* multiecho CMR is an established methodology for assessment of iron overload in heart and other organs. It is commonly recognized that MR sequences used in the clinical practice provide the best precision in T2* measurement in the range 3-20 ms, while an increasing error is expected out of this range. However, the dependence of the expected error from T2* and acquisition parameters is unknown.
Purpose The objective of this study is to quantify the precision limit of T2* assessment exploiting the Cramer-Rao lower bounds theory (CRLB).
Methods CRLB provide a fundamental limit to the accuracy in determination of the T2* value from experimental data; for any estimation method, the error in the parameter (measured as the standard deviation or SD) must be greater that or equal to the CRLB. CRLB for T2* estimation were evaluated tacking into account the statistics (i.e. MR signal and noise) of MR images involved in the measurements obtained from image data acquired during the MIOT project. CRLB were evaluated for several echo times
configuration used in the clinical setting on GE 1.5 T scanners for iron overload evaluation in thalassemia patients.
Results Figure 1.a shows CRLB for percent error in commonly used single breath-hold sequences with first echo time at 2 ms and 1.4 ms, echo spacing 2.26 ms, 10 echoes. Achievable measurement error is lower than 10% in the range 3-40 ms if minimum TE of 2 ms is used and lower than 10% in the range 2.5-40 ms for minimum TE of 1.4 ms. Only 3 patients (0.3%) had a global T2* < 3 ms among the 1324 patients in the MIOT database. Figure 1.b shows CRLB for percent error for low T2* values for the two single-breath-hold sequences previous described and a multi-breath-hold seque
Data Loading...
