Accurate simultaneous quantification of liver steatosis and iron overload in diffuse liver diseases with MRI

Abstract

Purpose: To evaluate the diagnostic performances of 3 Tesla multi-echo chemical shift-encoded gradient echo magnetic resonance (MECSE-MR) imaging to simultaneously quantify liver steatosis and iron overload in a wide spectrum of diffuse liver diseases having biopsy as reference standard. Methods: MECSE-MR-acquired images were used to calculate fat fraction and iron content in a single breathhold in 109 adult patients. Proton density fat fraction (PDFF) was prospectively estimated using complexbased data reconstruction with multipeak fat modeling. Water R2* was used to estimate iron content. Biopsy was obtained in all cases, grading liver steatosis, siderosis, inflammation, and fibrosis. Differences in PDFF and R2* values across histopathological grades were analyzed, and ROC curves analyses evaluated the MR diagnostic performance. Results: Calculated fat fraction measurements showed significant differences (p < 0.001) among steatosis grades, being unaffected by the presence of inflammation or fibrosis (p ‡ 0.05). A strong correlation was found between fat fraction and steatosis grade (R S = 0.718, p < 0.001). Iron deposits did not affect fat fraction quantitation (p ‡ 0.05), except in cases with severe iron overload (grade 4). A strong positive correlation was also observed between R2* measurements and iron grades (R S = 0.704, p < 0.001). Calculated R2* values were not different across grades of steatosis, inflammation, and fibrosis (p ‡ 0.05). Conclusion: A MECSE-MR sequence simultaneously quantifies liver steatosis and siderosis, regardless coexisting liver inflammation or fibrosis, with high accuracy in a wide spectrum of diffuse liver disorders. This sequence can be acquired within a single breath-hold and can be implemented in the routine MR evaluation of the liver.

Liver R2* is affected by both iron and fat: A dual biopsy‐validated study of chronic liver disease

“…These patients typically have a very high LIC of 10–30 mg/g; in contrast, typical chronic liver disease (CLD) patients referred to a hepatology department are expected to have a much lower LIC of around or below 1.2 mg/g, which is considered the upper limit of normal LIC . Later work has studied R2* in other patient groups with lower levels of LIC, although few studies have compared R2* to both histology and quantitative elemental analysis of LIC …”

Quantitative analysis of hepatic iron in patients suspected of coexisting iron overload and steatosis using multi‐echo single‐voxel magnetic resonance spectroscopy: Comparison with fat‐saturated multi‐echo gradient echo sequence

“…There have been some studies focused on simultaneous R Ã 2 and fat evaluation. 9,14,[35][36][37] The major advantage of GRE-based sequences, especially those using a 3D acquisition, over SVS is that simultaneous fat and iron quantification can be performed for the whole liver in one breathhold, in a clinical setting. However, separating the fat and water signal contributions may be challenging with iron overload.…”

Liver MRI: From basic protocol to advanced techniques

“…Moreover, because liver T2* is related to the amount of iron deposition, it can also be used for simultaneous quantification of iron deposits [36,[40][41][42]. Nevertheless, because large iron content lead to extremely low signal in GRE sequences, PDFF measurements may be corrupted in livers with severe iron overload [41]. Fat measurements can be performed in parametric maps, which have the advantage to demonstrate not only the amount but also the distribution of fat throughout the liver parenchyma (Fig.…”

“…PDFF quantification can be performed with commercially available tools (IDEAL-IQ ® , GE; mDIXON Quant ® , PHILIPS), or using in-house developed software. MECSE-MR imaging sequences are accurate for quantification of hepatic steatosis [41,43,44], being repeatable [45] and reproducible across different MR scanner platforms at 1.5T and 3T scanners [46].…”

“…As mentioned above, MECSE-MR sequences, the same as described for fat quantification, can also be used for R2* estimation and LIC quantification (Figs. 9 and 10) [40][41][42]48] while simultaneously assessing the liver fat content (Figs. 9 and 10).…”