Gennaro Restaino MD, Presenter: Nothing to Disclose

Silvia Roiati, Abstract Co-Author: Nothing to Disclose

Andrea Caulo MD, Abstract Co-Author: Nothing to Disclose

Massimiliano Missere MD, Abstract Co-Author: Nothing to Disclose

Alessia Pepe MD, Abstract Co-Author: Nothing to Disclose

Giuseppina Sallustio MD, Abstract Co-Author: Nothing to Disclose

Liver iron overload affects many important conditions like hemochromatosis, thalassemia major, and chronic viral hepatitis. MRI multiecho GRE sequence has been established in clinical practice as a feasible, accurate and reproducible means for liver iron overload assessment. Diffusion weighted imaging (DWI) is very sensitive to susceptivity effects like those caused by iron deposits. Purpose of the study is to determine the diagnostic performance of DWI, compared to multi-echo T2*-weighted imaging, for hepatic iron quantification in patients with thalassemia major. 

53 patients with thalassemia major and 20 healthy volunteers underwent liver MRI with 1.5T scanner. Liver T2* was assessed with a multiecho GRE sequence. ADC values were measured in the same hepatic region with EPI-DWI sequence with 2 different b-values (600 and 1000). Subjects were classified, according to liver T2*, in 4 groups: (I)no iron overload, (II)borderline, (III)slight, and (IV)moderate/severe overload. ADC values were compared in the groups with ANOVA with Dunnett’s adjustment.  

All 20 volunteers resulted in iron burden group I; amongst the patients, 9 were in group I, 24 in group II, 8 in group III, and 12 in group IV. The mean ADC values in the groups were: with b=600: I=0.001249; II=0.001488; III=0.000697; IV=0.000371; with b=1000: I=0.001152; II=0.001108; III=0.000309; IV=0.000124. In both DWI acquisitions it was impossible to confidently separate the groups I from II and the groups III from IV because of the overlapping of 95% confidence limits. After grouping I-II groups (group A: absent and borderline overload) and III-IV groups (group B: slight, moderate and severe overload), the mean ADC values and confidence limits were: with b=600 A: 0.001422 (0.001309-0.001535); B: 0.000501 (0.000356-0.000647); with b=1000 A: 0.001120 (0.001055-0.001186); B: 0.000198 (0.000114-0.000282). Hence, in DWI images with either b=600 and b=1000, there wasn’t any overlap between ADC values measured in the two iron burden groups.  

DWI with b=600 and b=1000 had excellent performance for differentiating subjects with absent or borderline iron overload from subjects with slight to severe iron overload.

DWI with b=600 and b=1000 may be used for assessing liver iron overload when dedicated software for T2* measurement is not available

Restaino, G, Roiati, S, Caulo, A, Missere, M, Pepe, A, Sallustio, G, Diffusion-weighted Imaging for Quantification of Hepatic Iron Deposition in Patients with Thalassemia Major: Comparison with Multi-Echo T2*-weighted Imaging.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11005132.html