Original Research Single Region of Interest Versus Multislice T2* MRI Approach for the Quantification of Hepatic Iron Overload Antonella Meloni, MSc, 1 * Antongiulio Luciani, MD, 2 Vincenzo Positano, MSc, 1 Daniele De Marchi, RT, 1 Gianluca Valeri, MD, 3 Gennaro Restaino, MD, 4 Eliana Cracolici, MD, 5 Vincenzo Caruso, MD, 6 Maria Chiara Dell’Amico, PhD, 1 Brunella Favilli, MSc, 1 Massimo Lombardi, MD, 1 and Alessia Pepe, MD, PhD 1 Purpose: To evaluate the effectiveness of the single ROI approach for the detection of hepatic iron burden in tha- lassemia major (TM) patients in respect to a whole liver measurement. Materials and Methods: Five transverse hepatic slices were acquired by a T2* gradient-echo sequence in 101 TM patients and 20 healthy subjects. The T2* value was cal- culated in a single region of interest (ROI) defined in the medium-hepatic slice. Moreover, the T2* value was extracted on each of the eight ROIs defined in the func- tionally independent segments. The mean hepatic T2* value was calculated. Results: For patients, the mean T2* values over segments VII and VIII were significantly lower. This pattern was substantially preserved in the two groups identified con- sidering the T2* normal cutoff. All segmental T2* values were correlated with the single ROI T2* value. After the application of a correction map based on T2* fluctuations in the healthy subjects, no significant differences were found in the segmental T2* values. Conclusion: Hepatic T2* variations are low and due to artifacts and measurement variability. The single ROI approach can be adopted in the clinical arena, taking care to avoid the susceptibility artifacts, occurring mainly in segments VII and VIII. Key Words: multislice multiecho T2*; liver; thalassemia major; iron overload J. Magn. Reson. Imaging 2011;33:348–355. V C 2011 Wiley-Liss, Inc. PEOPLE WITH THALASSEMIA major (TM) require reg- ular blood transfusions, which can lead to iron over- load in tissues because humans have no mechanism for eliminating excess iron (1). Excess body iron is highly toxic (2). This toxicity involves many organs such as the liver and heart, leading to a variety of se- rious diseases, which can be managed effectively or prevented. Therefore, early diagnosis of iron overload and appropriate and tailored chelation therapy are critical (3). MRI is the only technique that quantitatively and noninvasively assesses both myocardial and liver bur- den (4). MRI multi-echo T2-star (T2*) sequences allow rapid monitoring of iron deposition, exploiting the fact that paramagnetic iron compounds produce variability in susceptibility, shortening the T2* relaxation time (5). For the heart, a multislice approach was set up (6,7) to detect the heterogeneous myocardial iron distribution shown by histological studies (8,9). For the liver, a sin- gle transverse slice is traditionally acquired in clinical practice and the T2* measurement is performed in a region of interest (ROI) of the parenchyma (7,10,11). The use of the conventional single ROI technique has been partially due the fact that the early development of the T2* sequence in single echo multi-breathhold required approximately nine 10-s breathholds to ac- quire a single slice. Maris et al averaged T2* values obtained from two ROIs placed in two orthogonal slices (12). The T2* obtained was taken as representative of the T2* value for the whole liver and has been shown to correlate with iron overload assessment performed through biopsies (10,11). Liver iron overload estimation by the ROI-based approach may suffer from sampling errors due to the choice of slice location and the user-dependent place- ment of the ROI. In particular, heterogeneity in liver 1 Fondazione G.Monasterio CNR-Regione Toscana and Institute of Clinical Physiology, Pisa, Italy. 2 Istituto di Radiologia, Az. Osp. ‘‘Garibaldi’’, Presidio Ospedaliero Nesima, Catania, Italy. 3 Radiology Department, Azienda Ospedaliero-Universitaria Ospedali Riuniti ‘‘Umberto I-Lancisi-Salesi’’, Ancona, Italy. 4 Radiology Department, ‘‘John Paul II’’ Catholic University, Campobasso, Italy. 5 Department of Radiology, University of Palermo, Palermo, Italy. 6 Unita ` Operativa Dipartimentale Talassemia, P.O. ‘‘S. Luigi-Curro `’’ - ARNAS Garibaldi, Catania, Italy. *Address reprint requests to: A.M., Fondazione G.Monasterio CNR-Regione Toscana and Institute of Clinical Physiology, Via Mor- uzzi, 1 - 56124 Pisa, Italy. E-mail: antonella.meloni@ifc.cnr.it Received May 21, 2010; Accepted October 13, 2010. DOI 10.1002/jmri.22417 View this article online at wileyonlinelibrary.com. JOURNAL OF MAGNETIC RESONANCE IMAGING 33:348–355 (2011) V C 2011 Wiley-Liss, Inc. 348