Guido Matthias Kukuk¹, Alois Martin Sprinkart¹, Wolfgang Block¹, Holger Eggers², Jürgen Gieseke^1,3, Kanishka Hittatiya¹, Patrick Kupczyk¹, Julian Luetkens¹, Rami Homsi¹, Vera Keil¹, Michael Meier-Schroers¹, Milka Marinova¹, Asadeh Lakghomi¹, Dariusch Hadizadeh¹, Hans Heinz Schild¹, and Frank Träber^1
1University of Bonn, Bonn, NRW, Germany, ²Philips Research Europe, Hamburg, Hamburg, Germany, ³Philips Healthcare, Best, NL, Netherlands

The availability of various non-invasive and invasive techniques for liver fat quantification raises the question for comparability and congruence of quantitative results. Therefore we performed a systematic comparison of mDixon MRI techniques, MRS and two different histologic methods for liver fat quantification. Our results demonstrate that six-echo-mDixon, MRS and semi-automatic histologic fat quantification provide the most robust and congruent data. The performance characteristics and systematic differences of the various fat quantification methods should be considered in clinical routine and in further studies when comparing results obtained from biopsy with quantitative MRI or MRS.

Diego Hernando¹, Mustafa R. Bashir², Gavin Hamilton³, Jean M. Shaffer², Samir D. Sharma¹, Claude B. Sirlin³, Keitaro Sofue^2,4, Nikolaus M. Szeverenyi³, Takeshi Yokoo^5,6, Qing Yuan⁵, and Scott B. Reeder^1,7
1Radiology, University of Wisconsin-Madison, Madison, WI, United States, ²Radiology, Duke University, Durham, NC, United States, ³Radiology, University of California, San Diego, San Diego, CA, United States, ⁴Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan,⁵Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States, ⁶Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States, ⁷Medical Physics, University of Wisconsin-Madison, Madison, WI, United States

Chemical shift-encoded techniques for MRI-based quantification of triglyceride concentration have shown great promise for assessment of nonalcoholic fatty liver disease. However, direct validation of these techniques in phantoms across multiple sites, vendors, platforms and field strengths has yet to be performed. In this work, we address this gap by scanning the same oil-water phantom sequentially at four sites and comparing proton density fat-fraction measurements obtained with a common reconstruction algorithm. Our results demonstrate excellent accuracy, robustness and reproducibility of PDFF measurements in a phantom across three vendors, four sites, two field strengths, and eight magnets.

Axel J. Krafft^1,2, Ralf B. Loeffler¹, Ruitian Song¹, Mary E. McCarville¹, Matthew D. Robson³, Jane S. Hankins⁴, and Claudia M. Hillenbrand^1
1Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN, United States, ²Radiology - Medical Physics, University Medical Center Freiburg, German Cancer Consortium (DKTK), Heidelberg, Germany, ³Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom,⁴Hematology, St. Jude Children's Research Hospital, Memphis, TN, United States

Iron overload requires accurate assessment of hepatic iron content (HIC) which can be achieved via R2*-MRI using multi-echo gradient echo (mGRE) imaging. The precision in previous R2*-HIC studies is compromised for high HIC (> 20 mg Fe/g) as conventional mGRE techniques fail due to the rapid T2* signal decay. This limitation could be overcome using 2D ultra-short echo time (UTE) imaging which is, however, sensitive to various system imperfections hampering quantitative MRI. We describe a 2D UTE sequence that allows for precise R2* quantification for detection of iron overload. The sequence was evaluated in phantoms and in vivo.

Antonella Meloni¹, Gennaro Restaino², Stefania Renne³, Massimiliano Missere², Maria Chiara Resta⁴, Vincenzo Positano¹, Daniele De Marchi¹, Gaetano Roccamo⁵, Nicola Romano⁶, Maria Giovanna Neri¹, and Alessia Pepe^1
1CMR Unit, Fondazione G. Monasterio CNR-Regione Toscana, Pisa, Italy, ²Dipartimento di Radiologia, Università Cattolica del Sacro Cuore, Campobasso, Italy, ³Struttura Complessa di Cardioradiologia-UTIC, P.O. “Giovanni Paolo II”, Lamezia Terme, Italy, ⁴Struttura Complessa di Radiologia, OSP. SS. Annunziata ASL Taranto, Taranto, Italy, ⁵Unità di Prevenzione e Cura delle Mictrocitemie, PO di S. Agata di Militello (ASP-ME), S. Agata di Militello (ME), Italy, ⁶S.C. Medicina Trasfusionale, AO Arcispedale "S. Maria Nuova", Reggio Emilia, Italy

For the first time, we described the changes in pancreatic T2* values over a follow-up (FU) of 18 months and we evaluated prospectively the effectiveness of the three iron chelators in monotherapy in thalassemia major (TM) patients. At the dosages used in the clinical practice all three chelators in monotherapy allowed a significant reduction in pancreatic iron.

Bogdan Dzyubak¹, Yogesh K. Mariappan², Kevin J. Glaser¹, Sudhakar K. Venkatesh¹, and Richard L. Ehman^1
1Radiology, Mayo Clinic, Rochester, Minnesota, United States, ²Philips Healthcare, Bangalore, Karnataka, India

Magnetic Resonance Elastography (MRE) can measure the shear stiffness of soft tissues and is clinically used for hepatic fibrosis assessment. In liver pathologies resulting in high iron deposition(Ex: hemochromatosis), the typical gradient-echo MRE sequence can fail due to low SNR. To address this issue, two spin-echo based pulse sequences with short echo times have been developed. On patients with no iron overload, these modified sequences provide stiffness values that are in good agreement with the standard MRE, indicating that the current clinically used critical stiffness values can continue to be used for liver fibrosis assessment in patients with iron overload, when using these sequences as well.

Wen-Pei Wu^1,2, Ran-Chou Chen^2,3, Chen-Te Chou¹, Chih-Wei Lee¹, Cheng-In Hoi², Yi-Chun Wang^2,4, and Kwo-Whei Lee^1
1Radiology, Chang-Hua Christian Hospital, Chang-Hua, Taiwan, Taiwan, ²Biomedical Imaging and Radiological Science, National Yang-Ming Medical University, Taiwan, Taiwan, ³Radiology, Taipei city Hospital, Taipei, Taipei, Taiwan, Taiwan, ⁴Taoyuan general hospital ministry of health and welfare, Taiwan, Taiwan

Purpose The purpose of our study was to determine the influence of the histological or clinical parameters on liver stiffness (LS) measured by MRE. Methods 354 patients underwent MRE and histological examination during a 3-month interval. Clinical, laboratory data and histological parameters were recorded. The spleen volume was also measured using semiautomatic software. The influence of the parameters on the LS was investigated through uni- and multivariate standard regression. Results The univariate regression analysis showed age, etiology, fibrosis, activity, iron deposition, AST, ALT, total bilirubin, platelet and spleen size were significantly correlated with LS. In multiple regression analysis, three variables independently influenced LS: fibrosis, activity, and spleen size. The parameters together explained 58.7% of the variances of the LS, with fibrosis making the most unique contribution (26.0%). Conclusions The degree of liver fibrosis , activity and spleen size independently and significantly exaggerated LS.