Accurate estimate of pancreatic T2* values: how to deal with fat infiltration.
OBJECTIVE
We examined different approaches aimed to deal with the signal fluctuation of pancreatic T2* values due to fat infiltration in order to obtain accurate estimates of iron overload.


METHODS
Pancreatic T2* values were assessed in 20 patients (13 females, 37.24 ± 9.12 years) enrolled in the Myocardial Iron Overload in Thalassemia network without and with the application of fat suppression-FS (T2*-NoFS and T2*-FS). T2* values were assessed in three different ways: (1) from the immediate fit (original T2*); (2) discarding the echoes until the achievement of a good visual concordance between the signal and the model (final_vis T2*); (3) eliminating the echoes until the achievement of a fitting error (known) <5% (final_thres T2*).


RESULTS
For the T2*-NoFS sequence the original T2* values were significantly higher than the final_vis T2* values (difference:4.8 ± 6.1 ms; P < 0.0001) and the final_thres T2* values (difference:4.3 ± 6.1 ms; P = 0.006). For the T2*-FS sequence the original T2* values were comparable to final_vis and final_thres T2* values. The original T2*-FS values were significantly different from the original T2*-NoFS values. The final_vis T2*-FS values were comparable to the final_vis T2*-NoFS values and the final_thresh T2*-FS values were comparable to the final_thresh T2*-NoFS values. For both T2*-FS and T2*-NoFS sequences, the final_thres T2* values were not significantly different from the final_vis T2* values and no bias was present.


CONCLUSIONS
In the clinical practice, an accurate pancreatic iron overload assessment should be done by applying FS and, when needed, by discarding the TEs until the fitting error goes below 5%.
CMR Unit, Fondazione G. Monasterio CNR-Regione Toscana, Area della Ricerca S. Cataldo, Via Moruzzi, 1, 56124, Pisa, Italy. antonella.meloni@ftgm.it.|U.O.C. Bioingegneria e Ingegneria Clinica, Fondazione G. Monasterio CNR-Regione Toscana, Pisa, Italy. antonella.meloni@ftgm.it.
Antonella
A
Meloni
CMR Unit, Fondazione G. Monasterio CNR-Regione Toscana, Area della Ricerca S. Cataldo, Via Moruzzi, 1, 56124, Pisa, Italy.
Daniele
D
De Marchi
CMR Unit, Fondazione G. Monasterio CNR-Regione Toscana, Area della Ricerca S. Cataldo, Via Moruzzi, 1, 56124, Pisa, Italy.|U.O.C. Bioingegneria e Ingegneria Clinica, Fondazione G. Monasterio CNR-Regione Toscana, Pisa, Italy.
Vincenzo
V
Positano
CMR Unit, Fondazione G. Monasterio CNR-Regione Toscana, Area della Ricerca S. Cataldo, Via Moruzzi, 1, 56124, Pisa, Italy.
Maria Giovanna
MG
Neri
U.O.S. Sistemi Informatici, Fondazione G. Monasterio CNR-Regione Toscana, Pisa, Italy.
Maurizio
M
Mangione
CMR Unit, Fondazione G. Monasterio CNR-Regione Toscana, Area della Ricerca S. Cataldo, Via Moruzzi, 1, 56124, Pisa, Italy.
Petra
P
Keilberg
Centro Trasfusionale, Osp. Giovanni Paolo II, Olbia, Italy.
Maddalena
M
Lendini
Servizio Trasfusionale, Azienda USL n° 1, Sassari, Italy.
Carla
C
Cirotto
CMR Unit, Fondazione G. Monasterio CNR-Regione Toscana, Area della Ricerca S. Cataldo, Via Moruzzi, 1, 56124, Pisa, Italy.
Alessia
A
Pepe
D000273:Adipose Tissue / Q000473:pathology*; D000328:Adult; D005260:Female; D006801:Humans; D019190:Iron Overload / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D010179:Pancreas / Q000473:pathology*
Fat suppression; Iron overload; Magnetic resonance imaging; Pancreas T2*