Evaluation of Lung Metastases Based on Ultrashort Echo Time MRI

Inclusion Criteria: * Children diagnosed as hepatoblastoma (including treated with neoadjuvant chemotherapy but not surgery) * Recent chest CT scan (within 14 days) * No MRI contraindications * The guardian of the children are willing to undergo the examination after full communication and informed consent Exclusion Criteria: * MRI contraindications (including but not limited to: contrast medium allergy; Claustrophobia;Metal implants;chronic kidney disease≥stage 3 (glomerular filtration rate \< 60 mL min-1 (1.73 m2)-1)) * Patients with hepatoblastoma aged 14 years and above * Children after surgery for hepatoblastoma * Application of any contrast medium within 24 h before the MRI and/or CT examinations * There is a concomitant medical condition (e.g. poorly controlled hypertension, severe diabetes, neurological or psychiatric illness, etc.) or any other condition that would seriously endangers the subject's safety, may confuse the study results, or may interfere with the subject's completion of the study according to the investigator's judgment.