| Abstract: |
OBJECTIVE. The purpose of this study was to assess the effect of hepatic iron deposition on apparent diffusion coefficient (ADC) values measured with single-shot echo-planar imaging (EPI) diffusion-weighted MRI (DWI) in patients with liver cirrhosis and in vitro. MATERIALS AND METHODS. Fifty-two patients with liver cirrhosis who underwent breath-hold single-shot EPI DWI at 1.5 T before liver transplantation were retrospectively assessed. Estimated signal-to-noise ratio (SNR est) and ADC were measured in the right hepatic lobe (for b values of 50 and 500 s/mm 2). SNR est and ADC were compared between patients stratified by pathologic iron grade using the Mann-Whitney test. Hepatic ADC values were correlated to T2*values using the Spearman correlation test in a subset of patients. In addition, a phantom consisting of solutions of varying iron concentrations was imaged with single-shot EPI DWI and T2*imaging, and iron concentration was correlated with ADC and T2*. RESULTS. In phantoms, there was a decrease in ADC and T2*with increasing iron concentration (r = -0.95 and -0.92, respectively; p < 0.05). Patients with hepatic siderosis had significantly lower SNR est and ADC compared with patients without siderosis (p < 0.0001). SNR est at b = 50 s/mm 2 and b = 500 s/mm 2 and ADC had a significant negative correlation with pathologic iron grade (r = -0.67 to 0.77, p < 0.0001). There was a significant correlation between liver T2*and ADC (r = 0.83, p < 0.0001). CONCLUSION. Hepatic siderosis lowers liver ADC and should be taken into account when using ADC for diagnosing liver cirrhosis. © American Roentgen Ray Society. |
