Purpose: We investigated the relationships between KRAS gene status and local tumor progression (LTP) of colorectal liver metastases (CLMs) after treatment with percutaneous ultrasound-guided radiofrequency ablation (RFA). Materials and methods: Clinical and imaging data from 76 patients (154 lesions) with CLM who underwent percutaneous ultrasound-guided RFA and had KRAS gene test results between January 2012 and June 2016 were analyzed. The average lesion size was 2.3 ± 1.0 cm (range 0.9-5.7 cm); 38 cases (82 lesions) had wild-type KRAS, and 38 cases (72 lesions) had KRAS mutations. Results: The technique effectiveness was 98.1% (151/154), and the LTP rate was 18.2% (28/154) after RFA, which was performed between January 2012 and November 2017. The mean and median followup were 32.7 ± 2.5 and 32.0 ± 2.6 months (range 1-70 months), respectively. Cumulative LTP rates at 6 months and 1, 2 and 3 years post-RFA for all patients were 7.4, 14.5, 17.8 and 19.2%, respectively. The LTP rate for patients with mutant KRAS (27.8% [20/72]) was significantly higher than that in patients with wild-type KRAS (9.8% [8/82]; p ¼ .004). The cumulative LTP rates at 6 months and 1, 2 and 3 years post-RFA were 4.0, 11.1, 11.1 and 11.1%, respectively, for patients with wild-type KRAS and 11.2, 18.4, 25.2 and 36.2%, respectively, for patient with mutant KRAS (p ¼ .011). Univariate (p ¼ .011) and multivariate analyses (p ¼ .005) showed that KRAS genotype in liver metastases was predictive of LTP. Multivariate analysis also showed that ablation margin size (p< .001) and modified clinical risk score (CRS; p ¼ .033) were independent prognostic factors for LTP. Conclusions: KRAS gene status of liver metastatic lesions was associated with LTP rates after RFA of CLM. Ablation margin size and modified CRS were also independent prognostic factors for LTP.
Purpose: To compare long-term outcomes of percutaneous radiofrequency ablation for colorectal liver metastases in perivascular versus non-perivascular locations. Methods: This retrospective study included 388 consecutive patients with colorectal liver metastases (246 men, 142 women; age range 27-86 years) who underwent percutaneous radiofrequency ablation between January 2006 and December 2018. Propensity-score matching was performed for groups with perivascular and nonperivascular colorectal liver metastases. Rates of accumulative local tumor progression, overall survival, intra/extrahepatic recurrence, and complications were compared between the two groups. Results: We successfully matched 104 patients each in the perivascular and nonperivascular groups (mean age: 60.
Purpose: To investigate the differential diagnostic value of computer-aided color parametric imaging (CPI) and contrast-enhanced ultrasound (CEUS) in hepatocellular adenoma (HCA) and well-differentiated hepatocellular carcinoma (wHCC).Method: A total of 38 patients who underwent CEUS and were pathologically diagnosed with HCA (10 cases) and wHCC (28 cases) were reviewed retrospectively. The differences between the radiological features of HCA and wHCC were compared by two readers, blinded to the final diagnosis.Results: (a) Sonographic features: on gray-scale ultrasound, halo sign was more common in wHCC than in HCA (60.7% vs. 10.0%, p = 0.009). On CEUS, hyper-or isoenhancement was more common in HCA in the portal phase (90.0% vs. 50.0%; p = 0.022). On CPI mode, HCA was inclined toward centripetal enhancement (60.0% vs. 14.3% p = 0.010). HCA was characterized by the presence of pseudocapsule enhancement (50.0% vs. 14.3%; p = 0.036). Quantitative analysis showed that the arrival time of HCA was earlier than that of wHCC (12.4 ± 3.7 s vs. 15.9 ± 3.2 s; p = 0.006). (b) Interobserver agreement was improved by using CPI compared with CEUS. The diagnostic sensitivity, specificity, and accuracy of the combination were 80.0%, 85.7%, and 84.2%, respectively.Conclusions: CEUS combined with CPI can provide effective information for the differential diagnosis of HCA and wHCC, especially for the non-experienced radiologists.
Purpose: To investigate the effects of ablation time and distance between the radiofrequency ablation (RFA) electrode tip and a large vessel on the ablation zone in beagle livers. Methods: Sixty-one percutaneous RFA coagulation zones were created near large vessels in 10 beagle livers in vivo. The ablated lesions were divided into four groups based on ablation time and distance between the electrode tip and a large vessel (group A, 3 min 0.5 cm; group B, 3 min 0 cm; group C, 5 min 0.5 cm; group D, 5 min 0 cm). The ablated area, long-axis diameters, short-axis diameters, and vessel wall injury were examined. Results: With a fixed ablation time, the ablation zone created with the electrode tip at 0.5 cm from the large vessel was significantly larger than at 0 cm (p < .05). At a fixed distance between the electrode tip and vessel, the ablation zone created for 5 min was significantly larger than for 3 min (p < .05). The frequency of vessel wall injury in the 0 cm groups was significantly higher than that in the 0.5 cm groups (37.5% vs. 6.9%; p ¼ .003, odds ratio, 7.43). The ratio of width to depth (Dw/Dz) was larger in the 0.5 cm groups than in the 0 cm groups (p < .001).
Conclusion:The ablation zone increased with longer ablation times and greater distances between the RFA tip and large vessels for perivascular lesions. The distance between the needle tip and blood vessels is an important factor that affects the overall ablation outcome.
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