<b><i>Background:</i></b> Radiomics has emerged as a new approach that can help identify imaging information associated with tumor pathophysiology. We developed and validated a radiomics nomogram for preoperative prediction of microvascular invasion (MVI) in hepatocellular carcinoma (HCC). <b><i>Methods:</i></b> Two hundred and eight patients with pathologically confirmed HCC (training cohort: <i>n</i> = 146; validation cohort: <i>n</i> = 62) who underwent preoperative gadoxetic acid-enhanced magnetic resonance (MR) imaging were included. Least absolute shrinkage and selection operator logistic regression was applied to select features and construct signatures derived from MR images. Univariate and multivariate analyses were used to identify the significant clinicoradiological variables and radiomics signatures associated with MVI, which were then incorporated into the predictive nomogram. The performance of the radiomics nomogram was evaluated by its calibration, discrimination, and clinical utility. <b><i>Results:</i></b> Higher α-fetoprotein level (<i>p</i> = 0.046), nonsmooth tumor margin (<i>p</i> = 0.003), arterial peritumoral enhancement (<i>p &#x3c;</i> 0.001), and the radiomics signatures of hepatobiliary phase (HBP) T1-weighted images (<i>p &#x3c;</i> 0.001) and HBP T1 maps (<i>p &#x3c;</i> 0.001) were independent risk factors of MVI. The predictive model that incorporated the clinicoradiological factors and the radiomic features derived from HBP images outperformed the combination of clinicoradiological factors in the training cohort (area under the curves [AUCs] 0.943 vs. 0.850; <i>p</i> = 0.002), though the validation did not have a statistical significance (AUCs 0.861 vs. 0.759; <i>p</i> = 0.111). The nomogram based on the model exhibited C-index of 0.936 (95% CI 0.895–0.976) and 0.864 (95% CI 0.761–0.967) in the training and validation cohort, fitting well in calibration curves (<i>p</i> &#x3e; 0.05). Decision curve analysis further confirmed the clinical usefulness of the nomogram. <b><i>Conclusions:</i></b> The nomogram incorporating clinicoradiological risk factors and radiomic features derived from HBP images achieved satisfactory preoperative prediction of the individualized risk of MVI in patients with HCC.

Diffusion-weighted MRI can provide additional information to differentiate HCC from DN. Combined with CE-MRI, DWI allows improved characterization of HCC versus DN in cirrhotic liver.

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• Lung cancer and consolidation differentiation is essential for treatment decision-making. • Perfusion and diffusion characteristics of lesions could help differential diagnosis. • IVIM can separate reflection of tissue diffusivity and microcapillary perfusion. • The relationship between perfusion quantified by IVIM and DCE-MRI is controversial.

Purpose: To evaluate the role of abdominal susceptibilityweighted imaging (SWI) in the detection of siderotic nodules in cirrhotic liver. Materials and Methods:Forty patients with pathologically identified liver cirrhosis and 40 age/sex-matched normal controls underwent T1-, T2-, T2*-weighted imaging and SWI at 3T. Two radiologists prospectively analyzed all magnetic resonance imaging (MRI) studies. Siderotic nodules detected by each imaging technique were counted for comparison. The conspicuity of siderotic nodules was assessed using a scale from 1 to 3 (1, weak; 2, moderate; 3, prominent).Results: The number of siderotic nodules detected by SWI (3863) was significantly greater than that of T1-weighted imaging (262, P < 0.001), T2-weighted imaging (842, P < 0.001), and T2*-weighted imaging (2475, P < 0.001). No suspected siderotic nodules were detected in normal controls by any imaging technique.Conclusion: SWI appears to provide the most sensitive method to detect siderotic nodules in cirrhotic liver.

AIM:To determine the accuracy of high-resolution magnetic resonance imaging (MRI) using phasedarray coil for preoperative assessment of T staging and mesorectal fascia infiltration in rectal cancer with rectal distention. METHODS:In a prospective study of 67 patients with primary rectal cancer, high-resolution magnetic resonance imaging (in-plane resolution, 0.66 × 0.56) with phased-array coil were performed for T-staging and measurement of distance between the tumor and the mesorectal fascia. The assessment of MRI was compared with postoperative histopathologic findings. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were evaluated. RESULTS:The overall magnetic resonance accuracy was 85.1% for T staging and 88% for predicting mesorectal fascia involvement. Magnetic resonance sensitivity, specificity, accuracy, positive predictive value, and negative predictive value was 70%, 97.9%, 89.6%, 93.3% and 88.5% for ≤ T2 tumors, 90.5%, 76%, 85.1%, 86.4% and 82.6% for T3 tumors, 100%, 95.2%, 95.5%, 62.5% and 100% for T4 tumors, and 80%, 90.4%, 88%, 70.6% and 94% for predicting mesorectal fascia involvement, respectively. CONCLUSION:High-resolution MRI enables accurate preoperative assessment for T staging and mesorectal fascia infiltration in rectal cancer with rectal distention.

• Gd-EOB-DTPA-enhanced MRI could give useful information on NAFLD. •HBP T 1 relaxation time measurement was useful for the evaluation of NAFLD. • HBP T 1 relaxation time measurement was as accurate as ∆%.

1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1251-1259.