Diagnosis of recurrent HCC: intraindividual comparison of gadoxetic acid MRI and extracellular contrast-enhanced MRI.

PURPOSE: To compare the efficacy of magnetic resonance imaging (MRI) with hepatobiliary agents (HBA-MRI) and MRI with extracellular contrast agents (ECA-MRI) for detection of recurrent hepatocellular carcinoma (HCC) after multiple treatments. METHODS: The institutional review board approved this retrospective study and waived the requirement for informed patient consent. A total of 135 patients with suspected HCC recurrence after 2-5 treatments (surgery, transarterial chemoembolization, and/or radiofrequency ablation) underwent both HBA-MRI and ECA-MRI within a 1 month interval. HBA-MRI and ECA-MRI were analyzed for HCC detection by two observers using a five-point scale. The diagnostic performances according to MRI modality were compared. RESULTS: A total of 136 liver lesions (121 HCCs and 15 benign lesions; median size, 1.9 cm) were identified. ECA-MRI showed greater sensitivity (90.9% vs. 76.9% for observer 1; 91.7% vs. 78.5% for observer 2) and accuracy (91.2% vs. 78.7% for observer 1; 91.9% vs. 80.2% for observer 2) than HBA-MRI for both observers (P = 0.002, 0.003). Fifteen (12.4%) HCCs were correctly diagnosed with ECA-MRI but not with HBA-MRI by both observers. Interobserver agreement was excellent (0.885) for ECA-MRI and substantial (0.749) for HBA-MRI. CONCLUSIONS: For detection of recurrent HCC, ECA-MRI was superior to HBA-MRI in terms of sensitivity and accuracy. Therefore, ECA-MRI could be the preferred imaging modality over HBA-MRI for assessing HCC recurrence following multiple treatments.

Clinically insignificant prostate cancer suitable for active surveillance according to Prostate Cancer Research International: Active surveillance criteria: Utility of PI-RADS v2.

BACKGROUND: Active surveillance (AS) is an important treatment strategy for prostate cancer (PCa). Prostate Imaging-Reporting and Data System (PI-RADS) v2 has been addressed, but few studies have reported the value of PI-RADS v2 for assessing risk stratification in patients with PCa, especially on selecting potential candidates for AS. PURPOSE: To investigate the utility of PI-RADS v2 and apparent diffusion coefficient (ADC) in evaluating patients with insignificant PCa, who are suitable for AS. STUDY TYPE: Retrospective. SUBJECTS: In all, 238 patients with PCa who met the Prostate Cancer Research International: Active Surveillance criteria underwent radical prostatectomy. FIELD STRENGTH/SEQUENCE: 3.0T, including T2 -weighted, diffusion-weighted, and dynamic contrast-enhanced imaging. ASSESSMENT: Insignificant cancer was defined histopathologically as an organ-confined disease with a tumor volume <0.5 cm3 without Gleason score 4-5. Patients were divided into two groups based on the PI-RADS v2 and tumor ADC: A, PI-RADS score ≤3 and ADC ≥1.095 × 10-3 mm2 /s; and B, PI-RADS score 4-5 or ADC <1.095 × 10-3 mm2 /s. Preoperative clinical and imaging variables were evaluated regarding the associations with insignificant cancer. RESULTS: Of the 238 patients, 101 (42.8%) were diagnosed with insignificant cancer on pathological findings. The number of positive cores, prostate-specific antigen density (PSAD), PI-RADS v2 and tumor ADC were significantly associated with insignificant cancer on univariate analysis (P < 0.05). However, multivariate analysis indicated tumor ADC (odds ratio [OR] = 4.57, P < 0.001) and PI-RADS v2 (OR = 3.60, P < 0.001) were independent predictors of insignificant cancer. Area under the receiver operating characteristics curve (AUC) reached 0.803 when PI-RADS v2 (AUC = 0.747) was combined with tumor ADC (AUC = 0.786). DATA CONCLUSION: The PI-RADS v2 together with tumor ADC may be a useful marker for predicting patients with insignificant PCa when considering AS. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1072-1079.