Metabolic activity assessment by 18 F-fluorodeoxyglucose positron emission tomography in patients with hepatocellular carcinoma undergoing Yttrium-90 transarterial radioembolization.

BACKGROUND AND AIM: 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) is a functional image technique that can inform clinical decisions related to prognosis. We investigated the predictive role of 18 F-fluorodeoxyglucose PET/CT in patients with hepatocellular carcinoma (HCC) undergoing Yttrium-90 (Y-90) transarterial radioembolization (TARE). METHODS: Patients with HCC treated with TARE and pre-TARE PET/CT scan were recruited between 2009 and 2013. Maximum standardized uptake value and tumor-to-non-tumorous liver uptake ratio (TLR) were measured. Tumor response was evaluated in accordance with modified RECIST criteria at 3-month intervals after Y-90 TARE. RESULTS: Forty patients were included in the final analysis. The median age was 56.5 years and male predominant. Disease control in treated lesion was achieved in 82.5% (n = 33) of patients. During median 18.3-month follow-up, 27.5% (n = 11) of patients achieved progression-free survival. The cutoff of TLR, which was related to the median value, did not affect disease control rate, progression-free survival, and overall survival in patients with Y-90 TARE. CONCLUSIONS: The TLR-based stratification may be a simple method, but our study did not show the usefulness in predicting prognosis in HCC patients with Y-90 TARE. Further studies with large number of patients are needed.

Assessment of cold sink effect in postulated renal cryoablation by analyzing radiographic ice ball on computed tomography.

OBJECTIVE: We analyzed CT characteristics of radiographic ice ball according to anatomical location and freezing number in renal cryoablation. METHODS: 30 patients who underwent percutaneous cryoablation for renal lesions. Computed tomography (CT) was conducted at 9 min during every freezing in order to evaluate a radiographic ice ball. Software was used to reconstruct CT images of the radiographic ice ball perpendicular to cryoprobes. For each radiographic ice ball, two types of radius were measured: (a) lateral radius from epicenter to perirenal direction and (b) medial radius from epicenter to renal sinus direction. Lateral and medial radius or diameters (lateral radius plus medial radius) during the first and second freezing were compared using paired t-test, respectively. RESULTS: Medial radius of radiographic ice ball was significantly shorter than lateral radius (first freezing, 13.8 vs 17.0 mm, p < 0.001; second freezing, 16.0 vs 19.3 mm, p < 0.001). The diameter during the second freezing was significantly longer than that during the first freezing (35.3 vs 30.8 mm, p < 0.001). CONCLUSION: In renal cryoablation, evaluating radiographic ice ball helps identify potential postulated cold sink effect in the central portion of kidney. Advances in knowledge: Radiologic information of postulated cold sink effect in the kidney may help secure sufficient safety margins.