Ji Hye Min

Radiofrequency ablation of very-early-stage hepatocellular carcinoma inconspicuous on fusion imaging with B-mode US: value of fusion imaging with contrast-enhanced US

Background/Aims To determine the value of fusion imaging with contrast-enhanced ultrasonography (CEUS) and computed tomography (CT)/magnetic resonance (MR) images for percutaneous radiofrequency ablation (RFA) of very-early-stage hepatocellular carcinomas (HCCs) that are inconspicuous on fusion imaging with B-mode ultrasound (US) and CT/MR images. Methods This retrospective study was approved by our institutional review board and the requirement for informed consent was waived. Fusion imaging with CEUS using Sonazoid contrast agent and CT/MR imaging was performed on HCCs (<2 cm) that were inconspicuous on fusion imaging with B-mode US. We evaluated the number of cases that became conspicuous on fusion imaging with CEUS. Percutaneous RFA was performed under the guidance of fusion imaging with CEUS. Technical success and major complication rates were assessed. Results In total, 30 patients with 30 HCCs (mean, 1.2 cm; range, 0.6-1.7 cm) were included, among which 25 (83.3%) became conspicuous on fusion imaging with CEUS at the time of the planning US and/or RFA procedure. Of those 25 HCCs, RFA was considered feasible for 23 (92.0%), which were thus treated. The technical success and major complication rates were 91.3% (21/23) and 4.3% (1/23), respectively. Conclusions Fusion imaging with CEUS and CT/MR imaging is highly effective for percutaneous RFA of very-early-stage HCCs inconspicuous on fusion imaging with B-mode US and CT/MR imaging.

Mistargeting after Fusion Imaging–Guided Percutaneous Radiofrequency Ablation of Hepatocellular Carcinomas

PURPOSE To evaluate the incidence and causes of mistargeting after fusion imaging-guided percutaneous radiofrequency (RF) ablation of hepatocellular carcinomas (HCCs). MATERIALS AND METHODS Between September 2011 and March 2013, 955 HCCs in 732 patients were treated with percutaneous RF ablation. Among them, ablation of 551 HCCs was accomplished under fusion imaging guidance, and seven mistargetings were noted in seven patients (male-to-female ratio = 6:1; mean age, 60.1 y; range, 47-73 y). The incidence of mistargeting and the cause of liver disease in the patients with mistargeting were evaluated. The causes of mistargeting were assessed according to the following classification: small size of HCC, subcapsular location, subphrenic location, confusion with pseudolesions, poor conspicuity of HCC, poor sonographic window, and poor electrode path. RESULTS The incidence of mistargeting after fusion imaging-guided RF ablation was 1.3% (7 of 551). All patients with mistargeting were hepatitis B virus carriers. The most common cause of mistargeting was the small size of HCC (100%; 7 of 7), followed by confusion with surrounding pseudolesions (85.7%; 6 of 7), subcapsular (71.4%; 5 of 7) and subphrenic locations (71.4%; 5 of 7), poor conspicuity of the HCC (71.4%; 6 of 7), poor sonographic window (28.6%; 2 of 7), and poor electrode path (28.6%; 2 of 7). CONCLUSIONS The incidence of mistargeting after fusion imaging-guided RF ablation was 1.3%. The most common cause of mistargeting was the small size of HCC, followed by confusion with surrounding pseudolesions, subcapsular and subphrenic locations, and poor conspicuity of the HCC.

Prediction of microvascular invasion of hepatocellular carcinomas with gadoxetic acid-enhanced MR imaging: Impact of intra-tumoral fat detected on chemical-shift images

PURPOSE To investigate the impact of intra-tumoral fat detected by chemical-shift MR imaging in predicting the MVI of HCC. MATERIALS AND METHODS Gadoxetic acid-enhanced MR imaging of 365 surgically proven HCCs from 365 patients (306 men, 59 women; mean age, 55.6 years) were evaluated. HCCs were classified into two groups, fat-containing and non-fat-containing, based on the presence of fat on chemical-shift images. Fat-containing HCCs were subdivided into diffuse or focal fatty change groups. Logistic regression analyses were used to identify clinical and MR findings associated with MVI. RESULTS Based on MR imaging, 66 tumors were classified as fat-containing HCCs and 299 as non-fat-containing HCCs. Among the 66 fat-containing HCCs, 38 (57.6%) showed diffuse fatty changes and 28 (42.4%) showed focal fatty changes. MVI was present in 18 (27.3%) fat-containing HCCs and in 117 (39.1%) non-fat-containing HCCs (P=0.07). Univariate analysis revealed that serum alpha-fetoprotein (AFP) and tumor size were significantly associated with MVI (P<0.001). A multiple logistic regression analysis showed that log AFP (odds ratio 1.178, P=0.0016), tumor size (odds ratio 1.809, P<0.001), and intra-tumoral fat (odds ratio 0.515, P=0.0387) were independent variables associated with MVI. CONCLUSION Intra-tumoral fat detected with MR imaging may suggest lower risk for MVI of HCC and, therefore, a possibly more favorable prognosis, but the clinical value of this finding is uncertain.

Value of Diffusion-Weighted MRI for Differentiating Malignant From Benign Intraductal Papillary Mucinous Neoplasms of the Pancreas

OBJECTIVE The purpose of this study was to evaluate whether the use of diffusion-weighted MRI (DWI) increases diagnostic accuracy in the differentiation of malignant from benign intraductal papillary mucinous neoplasms (IPMNs) of the pancreas over the accuracy of contrast-enhanced MRI with MRCP. MATERIALS AND METHODS A total of 61 patients with surgically resected IPMNs (19 malignant, 42 benign) who underwent gadoxetic acid-enhanced MRI, DWI, and MRCP were included. Two blinded observers evaluated two image sets, that is, conventional MRI with MRCP images versus combined conventional MRI with MRCP and DW images, and scored their confidence for malignancy of IPMNs. Qualitative analyses of the IPMNs were also conducted. Diagnostic performance (ROC curve analysis), accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were evaluated. The Fisher exact test was used to compare groups. RESULTS The diagnostic performance (area under the ROC curve [Az]) with respect to predicting malignancy of IPMNs improved significantly for both observers after additional review of DW images (p < 0.05). The diagnostic accuracy, sensitivity, specificity, PPV, and NPV of combined conventional and DW images were higher than those of conventional MR images alone. Diffusion restriction was more often present in malignant IPMNs (78.9%) than in benign IPMNs (16.7%) (p < 0.001) with excellent interobserver agreement (ĸ = 0.965). CONCLUSION Compared with conventional MRI alone, adding DWI to conventional MRI improves diagnostic accuracy with increased specificity for differentiating malignant from benign IPMNs of the pancreas.

Radiofrequency Ablation Combined with Chemoembolization for Intermediate-Sized (3-5 cm) Hepatocellular Carcinomas Under Dual Guidance of Biplane Fluoroscopy and Ultrasonography

Objective To assess the technical feasibility and local efficacy of percutaneous radiofrequency ablation (RFA) combined with transcatheter arterial chemoembolization (TACE) for an intermediate-sized (3-5 cm in diameter) hepatocellular carcinoma (HCC) under the dual guidance of biplane fluoroscopy and ultrasonography (US). Materials and Methods Patients with intermediate-sized HCCs were treated with percutaneous RFA combined with TACE. RFA was performed under the dual guidance of biplane fluoroscopy and US within 14 days after TACE. We evaluated the rate of major complications on immediate post-RFA CT images. Primary technique effectiveness rate was determined on one month follow-up CT images. The cumulative rate of local tumor progression was estimated with the use of Kaplan-Meier method. Results Twenty-one consecutive patients with 21 HCCs (mean size: 3.6 cm; range: 3-4.5 cm) were included. After TACE (mean: 6.7 d; range: 1-14 d), 20 (95.2%) of 21 HCCs were visible on fluoroscopy and were ablated under dual guidance of biplane fluoroscopy and US. The other HCC that was poorly visible by fluoroscopy was ablated under US guidance alone. Major complications were observed in only one patient (pneumothorax). Primary technique effectiveness was achieved for all 21 HCCs in a single RFA session. Cumulative rates of local tumor progression were estimated as 9.5% and 19.0% at one and three years, respectively. Conclusion RFA combined with TACE under dual guidance of biplane fluoroscopy and US is technically feasible and effective for intermediate-sized HCC treatment.

Recurrent Hepatocellular Carcinoma After Transcatheter Arterial Chemoembolization Planning Sonography for Radio Frequency Ablation

The purposes of this study were to evaluate the sonographic findings of recurrent hepatocellular carcinoma after transcatheter arterial chemoembolization and to determine how often the lesion conspicuity of the recurrent hepatocellular carcinoma makes it suitable for percutaneous sonographically guided radio frequency ablation.

Radiofrequency Ablation for Viable Hepatocellular Carcinoma around Retained Iodized Oil after Transcatheter Arterial Chemoembolization: Usefulness of Biplane Fluoroscopy Plus Ultrasound Guidance

Objective To assess the technical feasibility and local efficacy of biplane fluoroscopy plus US-guided percutaneous radiofrequency ablation (RFA) for viable hepatocellular carcinoma (HCC) around retained iodized oil after transcatheter arterial chemoembolization (TACE). Materials and Methods Our prospective study was approved by our institutional review board and informed consent was obtained from all participating patients. For patients with viable HCC around retained iodized oil after TACE, biplane fluoroscopy plus US-guided RFA was performed. We evaluated the rate of technical success and major complications on a post-RFA CT examination and local tumor progression with a follow-up CT. Results Among 40 consecutive patients, 19 were excluded due to one of the following reasons: poorly visible HCC on fluoroscopy (n = 13), high risk location (n = 2), RFA performed under monoplane fluoroscopy and US guidance (n = 2), and poorly identifiable new HCCs on US (n = 2). The remaining 21 patients with 21 viable HCCs were included. The size of total tumors ranged from 1.4 to 5.0 cm (mean: 3.2 cm) in the longest diameter. Technical success was achieved for all 21 HCCs, and major complications were observed in none of the patients. During the follow-up period (mean, 20.3 months; range, 6.5-29.9 months), local tumor progression was found in two patients (2/21, 9.5%). Distant intrahepatic metastasis developed in 76.2% (16/21) of patients. Conclusion When retained iodized oil around the tumor after TACE hampers the targeting of the viable tumor for RFA, biplane fluoroscopy plus US-guided RFA may be performed owing to its technical feasibility and effective treatment for viable HCCs.

A novel electrode with electromagnetic tip tracking in ultrasonography-guided radiofrequency ablation: a phantom, ex vivo, and in vivo experimental study.

ObjectivesThe objective of this study was to compare the targeting and ablation performance between a newly developed radiofrequency (RF) electrode embedded with an electromagnetic position sensor (EMPS) at the electrode tip and a conventional RF electrode. Materials and MethodsThe institutional animal care and use committee approved this study. The targeting of paint balls within phantoms was performed under ultrasonography guidance by 2 radiologists (beginner vs expert) with an “in-plane” and “out-of-plane” approaches using the new RF electrode and a conventional RF electrode (n = 20 for each method). To evaluate the targeting performance, the electrode placement time and the number of electrode pullbacks for redirection were compared between the 2 electrodes. The ablation performance was also compared by analyzing the ablation volumes in ex vivo bovine and in vivo porcine livers (n = 30 and n = 24, respectively) and the cellular viability of the ablation zone in in vivo specimens. ResultsIn the phantom study, the RF electrode embedded with an EMPS showed a significantly shorter electrode placement time compared with the conventional RF electrode in both the in-plane and out-of-plane approaches by both radiologists (P < 0.05). The electrode pullback rate for both radiologists was lower in the new RF electrode than in the conventional RF electrode, but it did not reach statistical significance in the in-plane approach by the expert (P = 0.059). The ablation volumes analyzed with and without cellular viability in the ex vivo and in vivo studies were not significantly different between the 2 electrodes (P > 0.05). ConclusionsThe RF electrode embedded with an EMPS is faster than the conventional electrode in the electrode placement into the target lesions. The ablation performance is not significantly different between the 2 electrodes.

Local tumour progression after loco-regional therapy of hepatocellular carcinomas: Value of fusion imaging-guided radiofrequency ablation

AIM To assess the value of fusion imaging of real-time ultrasonography (US) with liver computed tomography (CT)/magnetic resonance imaging (MRI) images for planning US of radiofrequency ablation (RFA) in improving conspicuity of the lesions and reducing false-positive detection of local tumour progression (LTP) found after transcatheter arterial chemoembolization (TACE) or RFA of hepatocellular carcinoma (HCC). MATERIALS AND METHODS This study was approved by the institutional review board and informed consent was waived. Fifty patients with LTP (mean ± SD, 1.5 ± 0.6 cm; range 0.5-3 cm) detected at follow-up CT or MRI were included. Planning US was performed by two radiologists using conventional US first and fusion imaging later in the same session. False-positive detection rates were assessed using conventional US based on the results of fusion imaging. The number cases of initially invisible tumours on conventional US that became visible after image fusion were also evaluated. The true-positive detection rate and conspicuity scores of the index tumours were compared between conventional US and fusion imaging. RESULTS On conventional US, 40 (80%) out of 50 HCCs with LTP were identified. However, the false-positive detection rate of conventional US was 12.5% (5/40). Out of 10 initially invisible HCCs with LTP on conventional US, six (60%) became visible after image fusion. The true-positive detection rate on conventional US was 70% (35/50), whereas it was increased to 92% (46/50) after image fusion (p = 0.0026). CONCLUSION Fusion imaging can improve the conspicuity of lesions and reduce the false-positive detection of LTP after TACE or RFA.

Differentiation between cholangiocarcinoma and hepatocellular carcinoma with target sign on diffusion-weighted imaging and hepatobiliary phase gadoxetic acid-enhanced MR imaging: Classification tree analysis applying capsule and septum

OBJECTIVES To assess the usefulness of classification tree analysis (CTA) for discrimination of hepatocellular carcinoma (HCC) with target sign on hepatobiliary phase (HBP) and/or diffusion-weighted image (DWI) from intrahepatic cholangiocarcinoma (ICC). METHODS This retrospective study was approved by the institutional review board. From among the 811 patients with histopathologically proven 79 ICCs and 732 HCCs, 69 patients with 69 (87.3%) ICCs and 115 patients with 115 HCCs (15.7%) including 25 scirrhous HCCs and 10 HCCs with central scar that showed the target sign either on HBP or on DWI were included. Two radiologists evaluated the presence of capsule, septum, and arterial enhancement pattern on MR imaging. Capsule, septum, arterial enhancement pattern, and target sign on HBP or DWI were used to classify the tumors using CTA. RESULTS On CTA, capsule was the initial predictor for assessing the probability of tumors being HCC. The CTA model demonstrated a sensitivity of 86.1%, specificity of 76.8%, and accuracy of 82.6% for discriminating between ICCs and HCCs. In 115 HCCs, only 16 (13.9%) tumors were misclassified as high probability of ICC, and 64.0% (16/25) scirrhous HCCs and 90.0% (9/10) HCCs with central scar were correctly classified as high probability of HCC. CONCLUSIONS Target sign either on HBP or on DWI was shown in 87.3% (69/79) of ICCs and 15.7% (115/732) of HCCs. The CTA applying capsule and septum may be useful for guiding correct diagnosis of atypical HCCs with the target sign from ICCs.