Non-invasive measurement of liver iron concentration using 3-Tesla magnetic resonance imaging: validation against biopsy.

OBJECTIVES: To evaluate the performance and limitations of the R2* and signal intensity ratio (SIR) methods for quantifying liver iron concentration (LIC) at 3 T. METHODS: A total of 105 patients who underwent a liver biopsy with biochemical LIC (LICb) were included prospectively. All patients underwent a 3-T MRI scan with a breath-hold multiple-echo gradient-echo sequence (mGRE). LIC calculated by 3-T SIR algorithm (LICSIR) and by R2* (LICR2*) were correlated with LICb. Sensitivity and specificity were calculated. The comparison of methods was analysed for successive classes. RESULTS: LICb was strongly correlated with R2* (r = 0.95, p < 0.001) and LICSIR (r = 0.92, p < 0.001). In comparison to LICb, LICR2* and LICSIR detect liver iron overload with a sensitivity/specificity of 0.96/0.93 and 0.92/0.95, respectively, and a bias ± SD of 7.6 ± 73.4 and 14.8 ± 37.6 µmol/g, respectively. LICR2* presented the lowest differences for patients with LICb values under 130 µmol/g. Above this value, LICSIR has the lowest differences. CONCLUSIONS: At 3 T, R2* provides precise LIC quantification for lower overload but the SIR method is recommended to overcome R2* limitations in higher overload. Our software, available at www.mrquantif.org , uses both methods jointly and selects the best one. KEY POINTS: • Liver iron can be accurately quantified by MRI at 3 T • At 3 T, R2* provides precise quantification of slight liver iron overload • At 3 T, SIR method is recommended in case of high iron overload • Slight liver iron overload present in metabolic syndrome can be depicted • Treatment can be monitored with great confidence.

Volumetric changes after (90)y radioembolization for hepatocellular carcinoma in cirrhosis: an option to portal vein embolization in a preoperative setting?

BACKGROUND: Contralateral hypertrophy after (90)Y radioembolization has been described in case reports, but the incidence and quantitative extent of liver volume modifications after this therapy are unknown. METHODS: This retrospective study examined patients with hepatocellular carcinoma and underlying cirrhosis treated by (90)Y radioembolization. The main inclusion criteria were unilateral treatment, no prior liver surgery, and computed tomographic scans allowing for volumetric assessments. Treated, tumor, and contralateral liver volumes were measured. Whole liver volume and the ratio of contralateral to total functional liver volume after a virtual hepatectomy were calculated. RESULTS: Data of 34 patients were analyzed. Response rates were 26 % according to Response Evaluation Criteria in Solid Tumors (RECIST) and 63 % according to modified RECIST. Median overall survival was 13.5 months. Median treated volume decreased from 938 mL (interquartile range [IQR] = 719) to 702 mL (IQR = 656) (p < 0.001), while median contralateral volume increased from 724 mL (IQR = 541) to 920 mL (IQR = 530) (p < 0.001). The whole liver volume remained stable, with a median volume of 1,702 mL (IQR = 568) versus 1,577 mL (IQR 670), respectively (p = 0.55). The mean maximal increase in contralateral volume was 42 % (95 % confidence interval 16-67). Overall, 13 patients (38.2 %) exhibited increases greater than 30 %, while 13 patients (38.2 %) showed no increase or showed increases less than 10 %. The median ratio of contralateral to total functional liver volume increased from 48.5 to 64.9 % (p < 0.001), with the proportion of patients with a ratio of ≥50 % increasing from 47.1 to 67.6 % (p = 0.013). CONCLUSIONS: (90)Y radioembolization induced frequent and similar increases in functional liver remnant volume compared with portal vein embolization. This technique should be tested in a prospective study phase 2 study before liver resection.