Document Detail

Standardized T2* map of normal human heart in vivo to correct T2* segmental artefacts.
MedLine Citation:
PMID:  17205488     Owner:  NLM     Status:  MEDLINE    
A segmental, multislice, multi-echo T2* MRI approach could be useful in heart iron-overloaded patients to account for heterogeneous iron distribution, demonstrated by histological studies. However, segmental T2* assessment in heart can be affected by the presence of geometrical and susceptibility artefacts, which can act on different segments in different ways. The aim of this study was to assess T2* value distribution in the left ventricle and to develop a correction procedure to compensate for artefactual variations in segmental analysis. MRI was performed in four groups of 22 subjects each: healthy subjects (I), controls (II) (thalassemia intermedia patients without iron overload), thalassemia major patients with mild (III) and heavy (IV) iron overload. Three short-axis views (basal, median, and apical) of the left ventricle were obtained and analyzed using custom-written, previously validated software. The myocardium was automatically segmented into a 16-segment standardized heart model, and the mean T2* value for each segment was calculated. Punctual distribution of T2* over the myocardium was assessed, and T2* inhomogeneity maps for the three slices were obtained. In group I, no significant variation in the mean T2* among slices was found. T2* showed a characteristic circumferential variation in all three slices. The effect of susceptibility differences induced by cardiac veins was evident, together with low-scale variations induced by geometrical artefacts. Using the mean segmental deviations as correction factors, an artefact correction map was developed and used to normalize segmental data. The correction procedure was validated on group II. Group IV showed no significant presence of segmental artefacts, confirming the hypothesis that susceptibility artefacts are additive in nature and become negligible for high levels of iron overload. Group III showed a greater variability with respect to normal subjects. The correction map failed to compensate for these variations if both additive and percentage-based corrections were applied. This may reinforce the hypothesis that true inhomogeneity in iron deposition exists.
Vincenzo Positano; Alessia Pepe; Maria Filomena Santarelli; Barbara Scattini; Daniele De Marchi; Anna Ramazzotti; Gianluca Forni; Caterina Borgna-Pignatti; Maria Eliana Lai; Massimo Midiri; Aurelio Maggio; Massimo Lombardi; Luigi Landini
Related Documents :
11099998 - Specificity of the stress electrocardiogram during adenosine myocardial perfusion imagi...
3673878 - St segment changes in exercise body surface mapping after myocardial infarction in pati...
2245108 - Transient myocardial ischaemia after acute myocardial infarction.
20401298 - Levofloxacin-induced torsades de pointes.
16194608 - Restoring an elliptical chamber during rebuilding a wrap around anterior infarction.
25468958 - Effect of spinal cord stimulation on myocardial perfusion reserve in patients with refr...
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  NMR in biomedicine     Volume:  20     ISSN:  0952-3480     ISO Abbreviation:  NMR Biomed     Publication Date:  2007 Oct 
Date Detail:
Created Date:  2007-09-11     Completed Date:  2007-11-13     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8915233     Medline TA:  NMR Biomed     Country:  England    
Other Details:
Languages:  eng     Pagination:  578-90     Citation Subset:  IM    
Copyright Information:
John Wiley & Sons, Ltd.
MRI Laboratory, Institute of Clinical Physiology, CNR, Pisa, Italy.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Image Enhancement / methods*
Image Interpretation, Computer-Assisted / methods*
Magnetic Resonance Imaging / methods*
Myocardium / pathology*
Reference Values
Reproducibility of Results
Sensitivity and Specificity
Thalassemia / complications,  diagnosis*
Ventricular Dysfunction, Left / diagnosis*,  etiology*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Effect of signal-to-noise ratio and spectral linewidth on metabolite quantification at 4 T.
Next Document:  Non-patient factors related to rates of ruptured appendicitis.