Abbreviated MRI Protocol for the Assessment of Ablated Area in HCC Patients

Abstract

Background: Liver Imaging Reporting and Data Systems (LI-RADS) Treatment Response Algorithm (TRA) was created to provide a standardized assessment of hepatocellular carcinoma (HCC) following loco regional therapy. The aim of this study was to compare sensitivity of standard MRI protocol versus abbreviated protocol (only T1-Weigthed fat suppressed (FS) sequences pre- and post-contrast phase) in the detection of ablated area according to LI-RADS Treatment Response (LR-TR) categories. Methods: From January 2015 to June 2020, we selected 64 patients with HCC, who underwent Radiofrequency ablation (RFA) or Microwave ablation (MWA) treatment. According to inclusion criteria, 136 pathologically proven treated HCC (median 2, range 1–3 per patient; mean size 20.0 mm; range 15–30 mm) in 58 patients (26 women, 32 men; median age, 74 years; range, 62–83 years) comprised our study population. For each ablated area, abbreviated protocol, and standard Magnetic Resonance Imaging (MRI) studies were independently and blindly assessed in random order within and between three expert radiologists. Each radiologist assessed the ablated area by using the following categories: “LR-TR Non-viable” = 1; “LR-TR Equivocal” = 2 and “LR-TR Viable” = 0. Results: According to the concordance between MRI and Contrast enhancement ultrasound (CEUS) among 136 treated HCCs, 115 lesions were assessed as non-viable or totally ablate and 21 as viable or partially ablate. The accuracy for standard MRI protocol and abbreviated MRI protocol for predicting pathologic tumor viability of a consensus reading was 98.6% (sensitivity = 100%; specificity = 98.3%; positive predictive value = 91.3% and negative predictive value = 100%). No differences were found in sensitivity or specificity between standard MRI LR-TR viable and abbreviated MRI LR-TR viable categories (p value > 0.05 at McNemar test). Conclusion: The abbreviated dynamic protocol showed similar diagnostic accuracy to conventional MRI study in the assessment of treated HCCs, with a reduction of the acquisition study time of 30% respect to conventional MRI.

Per-Feature Accuracy of Liver Imaging Reporting and Data System Locoregional Treatment Response Algorithm: A Systematic Review and Meta-Analysis

“…Specifically, studies that reported on the performance of LR-TR viable category but did not report data on the performance of each imaging feature were excluded [18][19][20]. Finally, a total of 10 eligible articles reported the diagnostic performance of LR-TR viable features for diagnosing viable HCC (Table 1) [11][12][13][14][21][22][23][24][25][26]. Of the 10 eligible articles, 10 reported the performance of NMLIT with APHE [11][12][13][14][21][22][23][24][25][26], 8 reported that of NMLIT with washout appearance [11][12][13][14][22][23][24][25], and 6 reported that of NMLIT with enhancement similar to pretreatment [12][13][14]22,23,25].…”

“…Finally, a total of 10 eligible articles reported the diagnostic performance of LR-TR viable features for diagnosing viable HCC (Table 1) [11][12][13][14][21][22][23][24][25][26]. Of the 10 eligible articles, 10 reported the performance of NMLIT with APHE [11][12][13][14][21][22][23][24][25][26], 8 reported that of NMLIT with washout appearance [11][12][13][14][22][23][24][25], and 6 reported that of NMLIT with enhancement similar to pretreatment [12][13][14]22,23,25].…”

“…The characteristics of the finalized studies included in the meta-analysis are summarized in Table 1 (971 patients with 1,153 treated observations). Of the 10 included studies, 1 had a prospective study design [21], and 9 were of retrospective design [11][12][13][14][22][23][24][25][26]. Hepatitis B was the dominant etiology of liver disease in eight studies [11][12][13][14][22][23][24][25].…”

“…Of the 10 included studies, 1 had a prospective study design [21], and 9 were of retrospective design [11][12][13][14][22][23][24][25][26]. Hepatitis B was the dominant etiology of liver disease in eight studies [11][12][13][14][22][23][24][25]. Patients were treated only with conventional TACE in two studies [13,21], transarterial radioembolization in one study [25], and ablative therapy (RFA or microwave ablation) in two studies [24,26].…”

Diagnostic evaluation and ablation treatments assessment in hepatocellular carcinoma

“…In this setting, imaging observations depend highly on the type and the method of therapy delivery, the timing of treatment, and the imaging technique being used to observe the effects. Therefore, an evaluation based only on dimensional data is not appropriate to assess the efficacy of such complex treatments, since not always a positive response to treatment is linked to a size reduction; furthermore dimensional criteria do not allow the differentiation of the fibrotic tissue from the residual tumor [ 218 ]. The LI-RADS treatment response algorithm applies to multiphase CT or MRI used to assess response after local-regional therapy, which includes percutaneous therapy (eg, ethanol and radiofrequency or microwave ablation), transcatheter therapy (eg, transarterial chemoembolization or radioemboliza- tion), and external beam radiation therapy.…”