Pediatric Hepatoblastoma After Neoadjuvant Chemotherapy: Diagnostic Performance of MR in Staging POSTTEXT and Vascular Involvement

Abstract

BackgroundThe assessment of resectability after neoadjuvant chemotherapy of hepatoblastoma is dependent on Post‐Treatment EXTENT of Disease (POSTTEXT) staging and its annotation factors P (portal venous involvement) and V (hepatic venous/inferior vena cava [IVC] involvement), but MR performance in assessing them remains unclear.PurposeTo assess the diagnostic performance of contrast‐enhanced MR imaging for preoperative POSTTEXT staging and diagnosing vascular involvement in terms of annotation factors P and V in pediatric hepatoblastoma following neoadjuvant chemotherapy.Study TypeRetrospective.SubjectsThirty‐five consecutive patients (17 males, median age, 24 months; age range, 6–98 months) with proven hepatoblastoma underwent preoperative MR imaging following neoadjuvant chemotherapy.Field Strength/Sequence3.0 T; T2‐weighted imaging (T2WI), T2WI with fat suppression, diffusion weighted imaging, radial stack‐of‐the‐star/Cartesian 3D Dixon T1‐weighted gradient echo imaging.AssessmentThree radiologists independently assessed the POSTTEXT stages and annotation factors P and V based on the 2017 PRE/POSTTEXT system. The sensitivities and specificities were calculated for 1) diagnosing each POSTTEXT stage; 2) discrimination of stages III and IV (advanced) from those stages I and II (non‐advanced) hepatoblastomas; and 3) annotation factors P and V. The combination of pathologic findings and surgical records served as the reference standard.Statistical TestsSensitivity, specificity, Fleiss kappa test.ResultsThe sensitivity and specificity ranges for discriminating advanced from non‐advanced hepatoblastomas were 73.3%–80.0% and 80.0%–90.0%, respectively. For annotation factor P, they were 66.7%–100.0% and 90.6%, respectively. For factor V, they were 75.0% and 67.7%–83.9%, respectively. There was excellent, substantial, and moderate agreement on POSTTEXT staging (Fleiss kappa = 0.82), factors P (Fleiss kappa = 0.64), and factors V (Fleiss kappa = 0.60), respectively.Data ConclusionMR POSTTEXT provides reliable discrimination between advanced and non‐advanced tumors, and MR has moderate to excellent specificity at identifying portal venous and hepatic venous/IVC involvement.Evidence Level3Technical EfficacyStage 3