Clinical course of patients with hepatocellular carcinoma who experienced radiologic complete response after radioembolization.

Purpose: The purpose of this study is to elucidate the patterns of recurrence of hepatocellular carcinoma and to analyze factors that can predict recurrence after complete response to radioembolization. Materials and methods: A total of 289 consecutive patients who underwent radioembolization for the treatment of hepatocellular carcinoma at a single tertiary center were retrospectively reviewed. Baseline characteristics were collected and compared between the group showing complete response and the group showing noncomplete response. Data on recurrence status, time to recurrence, and the patterns of recurrence among the patients who showed radiologic complete response were collected. The group that maintained complete response and the group that experienced recurrence were compared, and the risk factors affecting recurrence were evaluated by logistic regression analysis. Results: The complete response rate was 24.9% (73/289). Age, sex, tumor markers, maximum tumor diameter, multiplicity, presence of vascular invasion, and target radiation dose were significantly different between the complete response and noncomplete response groups. The recurrence rate after complete response was 38.4% (28/73), and 67.9% (19/28) of recurrences occurred by 8 months after complete response. Eight patients who underwent resection/transplantation after complete response experienced no recurrence. Multiple tumors and a lower target radiation dose were independent risk factors of recurrence after complete response in the multivariate logistic regression. Conclusion: Hepatocellular carcinoma recurrence following complete response after radioembolization is not uncommon and frequently occurs within 1 year after complete response. Multiple tumors and a lower target radiation dose may be risk factors for recurrence.

Thoracic Duct Embolization for Treatment of Chyle Leakage After Thyroidectomy and Neck Dissection.

OBJECTIVE: This study aimed to evaluate the safety and efficacy of intranodal lymphangiography and thoracic duct embolization (TDE) for chyle leakage (CL) after thyroid surgery. MATERIALS AND METHODS: Fourteen patients who underwent intranodal lymphangiography and TDE for CL after thyroid surgery were included in this retrospective study. Among the 14 patients, 13 underwent bilateral total thyroidectomy with neck dissection (central compartment neck dissection [CCND], n = 13; left modified radical neck dissection (MRND), n = 11; bilateral MRND, n = 2), and one patient underwent left hemithyroidectomy with CCND. Ten patients (76.9%) had high-output CL (> 500 mL/d). Before the procedure, surgical intervention was attempted in three patients (thoracic duct ligation, n = 1; lymphatic leakage site ligation, n = 2). Lymphangiographic findings, technical and clinical successes, and complications were analyzed. Technical success was defined as the successful embolization of the thoracic duct after access to the lymphatic duct via the transabdominal route. Clinical success was defined as the resolution of CL or surgical drain removal. RESULTS: On lymphangiography, ethiodized oil leakage near the surgical bed was identified in 12 of 14 patients (85.7%). The technical success rate of TDE was 78.6% (11/14). Transabdominal antegrade access was not feasible due to the inability to visualize the identifiable cisterna chyli or a prominent lumbar lymphatic duct. Among patients who underwent a technically successful TDE, the clinical success rate was 90.1% (10/11). The median time from the procedure to drain removal was 3 days (with a range of 1-13 days) for the 13 patients who underwent surgical drainage. No CL recurrence was observed during the follow-up period (ranging from 2-44 months; median, 8 months). There were no complications, except for one case of chylothorax that developed after TDE. CONCLUSION: TDE appears to be a safe and effective minimally invasive treatment option for CL after thyroid surgery, with acceptable technical and clinical success rates.

Feasibility of Percutaneous Pancreatic Stent Placement in Postoperative Pancreaticojejunostomy Stenosis.

OBJECTIVE: To evaluate the role of percutaneous pancreatic stent placement in postoperative pancreaticojejunostomy stenosis (PJS). MATERIALS AND METHODS: This retrospective single-center study included seven procedures in five patients (four males and one female; median age, 63 years) who underwent percutaneous pancreatic stent placement for postoperative PJS between January 2005 and December 2021. The patients were referred to interventional radiology because of unfavorable anatomy or bowel abnormalities. The pancreatic duct was accessed under ultrasound and/or computed tomography guidance. A stent was placed after balloon dilatation of the PJS. Moreover, plastic stents were placed for the first two procedures, whereas bare-metal stents were used for the remaining five procedures. Technical success was defined as the successful placement of stents for the PJS, meanwhile, clinical success was defined as the normalization of pancreatic enzymes without recurrence of pancreatitis. RESULTS: Pancreatic duct access and stent placement were successfully performed in all patients (technical success rate: 100%). All the procedures initially yielded clinical success. However, recurrence of pancreatitis was observed after two procedures that used plastic stents because of stent migration at 0.3 and 3 months after the procedure. In contrast, no instances of recurrent pancreatitis were noted after metal stent placement for a follow-up duration of 1-36 months. No serious procedure-related adverse events were observed. CONCLUSION: Percutaneous pancreatic stent placement may be a viable option for patients with postoperative PJS in whom an endoscopic approach is not feasible. Metal stents may be considered over plastic stents for the management of PJS, considering the possible lower stent migration and infeasibility of frequent endoscopic stent exchange due to the altered anatomy.

Balloon Bronchoplasty for the Treatment of Bronchial Stenosis After Lung Transplantation: A Single-Center 10-Year Experience.

OBJECTIVE: To assess the safety and efficacy of balloon dilatation under dual guidance using fluoroscopy and bronchoscopy for treating bronchial stenosis following lung transplantation (LT), and to elucidate the factors associated with patency after the procedure. MATERIALS AND METHODS: From September, 2012, to April, 2021, 50 patients (mean age ± standard deviation, 54.4 ± 12.2 years) with bronchial stenosis among 361 recipients of LT were retrospectively analyzed. The safety of balloon dilatation was assessed by evaluating procedure-related complications. Efficacy was assessed by evaluating the technical success, primary patency, and secondary patency. Primary and secondary cumulative patency rates were calculated using the Kaplan-Meier method. The factors associated with patency after the procedure were evaluated using multivariable Cox hazard proportional regression analysis. RESULTS: In total, 65 bronchi were treated with balloon dilatation in 50 patients. The total number of treatment sessions was 277 and the technical success rate was 99.3% (275/277 sessions). No major procedure-related complications were noted. During the mean follow-up period of 34.6 ± 30.8 months, primary patency was achieved in 12 of 65 bronchi (18.5%). However, the patency rate improved to 76.9% (50 of 65 bronchi) after repeated balloon dilatation (secondary patency). The 6-month, 1-year, 3-year, and 5-year secondary patency rates were 95.4%, 90.8%, 83.1%, and 78.5%, respectively. The presence of clinical symptoms was a significant prognostic factor associated with reduced primary patency (adjusted hazard ratio [HR], 0.465; 95% confidence interval [CI], 0.220-0.987). Early-stage treatment ≤ 6 months (adjusted HR, 3.588; 95% CI, 1.093-11.780) and prolonged balloon dilatation > 5 min (adjusted HR, 3.285; 95% CI, 1.018-10.598) were associated with significantly higher secondary patency. CONCLUSION: Repeated balloon dilatation was determined to be safe and effective for treating bronchial stenosis following LT. Early-stage treatment and prolonged balloon dilatation could significantly promote long-term patency.

Clinical Outcomes of Transarterial Embolization for Chronic Achilles Tendinopathy Refractory to Conservative Treatment: A Pilot Study.

PURPOSE: To evaluate the effectiveness and safety of transarterial embolization (TAE) for chronic Achilles tendinopathy (AT) refractory to conservative treatment. MATERIALS AND METHODS: This retrospective study included 20 patients (12 men and 8 women; mean age, 30.3 years) who received TAE using imipenem/cilastatin sodium for refractory chronic AT from May 2019 to April 2021. Nine patients had bilateral involvement. A total of 29 procedures were performed (8 for nonathletes and 21 for athletes). If feasible, embolization was performed superselectively of the arterial branch demonstrating hypervascularity, early venous drainage, and/or supplying the pain site noted using a radiopaque marker. The visual analog scale (VAS, 0-10) score was used to assess pain symptoms at baseline and during the follow-up period (1 day; 1 week; 1, 3, and 6 months; and open period). Clinical success was defined as a decrease of >50% in the VAS score at 6 months when compared with baseline. RESULTS: In 25 (86.2%) of 29 procedures, clinical success was achieved. Significant decreases in the VAS scores were noted at 1 day, 1 week, 1 month, 3 months, and 6 months (6.86 at the baseline vs 3.48, 3.41, 3.10, 2.55, and 1.62, respectively; all P < .01). For patients available for the 12- and 24-month follow-ups (n = 19 and 6, respectively), the mean VAS scores significantly decreased (6.84 vs 2.00 and 7.33 vs 1.17, respectively; all P < .01). No serious adverse events were observed during follow-up. CONCLUSIONS: TAE may alleviate pain for patients with chronic AT refractory to the conservative treatment with a low risk of adverse events.

Clinical course and role of embolization in patients with spontaneous rupture of hepatocellular carcinoma.

Background: A diverse clinical course after the spontaneous rupture of hepatocellular carcinoma (HCC) renders nonstandardized treatment protocols. Purpose: To evaluate clinical course and role of transcatheter arterial embolization (TAE) in patients with rupture of HCC. Materials and methods: This retrospective study included 127 patients who were treated for ruptured HCC at single institution between 2005 and 2014. After multidisciplinary discussion, patients underwent medical management, TAE, emergency surgery or staged surgery. Patients were retrospectively divided into two groups based on the intent of treatment: curative and palliative. The rebleeding rate and 1-month and overall survival (OS) were compared between two groups. The incidence and survival of patients with intraperitoneal drop metastasis (IPDM) were also analyzed. Results: The overall rebleeding rate in patients who underwent TAE was 3.1% (3/96). One-month mortality rate was 6.3% (8/127). The rebleeding and 1-month mortality rates were not significantly different between two groups. OS was significantly higher in the curative treatment group (median: 12.0 vs 2.2 months, p<0.001). Among 96 patients who initially received TAE, ten patients underwent staged operation (10.4%). The median OS for medical management, TAE, emergency surgery and staged surgery was 2.8, 8.7, 19.1 and 71.1 months, respectively. Of all patients, 15.2% developed IPDM mostly within 1 year and their survival was poorer than that of patients without IPDM (median: 6.3 vs. 15.1 months, p<0.001). Conclusion: TAE provided effective immediate hemostasis with a low rebleeding rate and may serve as a bridge to elective surgery. IPDM frequently occurred within 1 year and manifested poor survival; thus, close surveillance should be considered for patients with spontaneous rupture of HCC.

Radioembolization for Hepatocellular Carcinoma: The Effects of Arterioportal Shunts on Nontargeted Liver Hypertrophy.

PURPOSE: To determine whether arterioportal shunting to the contralateral lobe attenuates liver function and hypertrophy of the nontargeted liver after radioembolization in patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: The current retrospective study included 46 patients who received radioembolization for HCC contained within the right lobe between 2012 and 2020. The patients were divided into the following groups on the basis of the presence and extent of arterioportal shunting: patients with retrograde arterioportal shunting to the left lobe (contralateral group) and patients with arterioportal shunt limited to the right lobe or no arterioportal shunt (control group). Safety profiles, including adverse events, tumor response, and overall survival, were compared. With the volume of the left lateral segment used as a surrogate marker for nontarget liver, the degree of hypertrophy was compared between the 2 groups at 3 and 6 months. RESULTS: Liver function significantly deteriorated in the contralateral group in a month (P ≤ .05). Tumor response and overall survival did not significantly differ between the 2 groups. The degree of hypertrophy was significantly higher in the control group than in the contralateral group at 3 months (10.6% vs 3.5%; P = .008) and 6 months (20.7% vs 2.4%; P < .001). CONCLUSIONS: In patients with arterioportal shunting to the contralateral lobe, hypertrophy of the nontarget liver may not occur and the liver function may be worsened.

Tumor volume measured using MR volumetry as a predictor of prognosis after surgical resection of single hepatocellular carcinoma.

PURPOSE: To evaluate the clinical value of tumor volume-measurement using magnetic resonance (MR) volumetry for predicting prognosis after surgical resection of single small-to-medium-sized hepatocellular carcinoma (HCC) (≤5cm). METHOD: This retrospective study included 162 consecutive patients who underwent preoperative gadoxetic acid-enhanced MRI and subsequent surgical resection for single HCC (≤5cm). Tumor volume was measured at hepatobiliary phase of MR images using semi-automated three-dimensional volumetric software program. Recurrence-free survival (RFS) and overall survival (OS) were estimated using Kaplan-Meier method. The Cox-proportional-hazard-model was used to evaluate clinical, pathologic, and radiologic prognostic factors. A minimal p-value approach based on log-rank test statistics was used to obtain the optimal-cutoff tumor volume for predicting RFS and OS. Inter-examiner reproducibility of MR volumetric measurements was assessed using intraclass correlation coefficient (ICC) and coefficient of variance (CV). RESULTS: After a median follow-up of 84.4 months (range, 2.8-126.5), HCC recurrence occurred in 69 (42.6%) patients and twenty-four (14.8%) patients died with estimated 5-year OS of 90.8%. Larger tumor volume was significantly associated with poor RFS(P = 0.018) and poor OS(P = 0.005) in multivariate analysis. For predicting RFS and OS after surgery, the optimal-cutoff of tumor volume was set at 4.0 mL and 4.0 mL, respectively, with larger volume ≥4.0 mL was significantly associated with poor RFS (hazard ratio[HR], 1.84, P = 0.023) and poor OS (HR, 2.66, P = 0.033). Inter-examiner reproducibility of tumor volume-measurement using MR-volumetry showed ICC of 0.980 and CV of 3.9%. CONCLUSIONS: Tumor volume-measurement using MR-volumetry is clinically feasible and reproducible, and can help predict RFS and OS after resection of single small-to-medium-sized HCC.

Effectiveness of radiologist training in improving reader agreement for Lung-RADS 4X categorization.

OBJECTIVES: To identify the agreement on Lung CT Screening Reporting and Data System 4X categorization between radiologists and an expert-adjudicated reference standard and to investigate whether training led to improvement of the agreement measures and diagnostic potential for lung cancer. METHODS: Category 4 nodules in the Korean Lung Cancer Screening Project were identified retrospectively, and each 4X nodule was matched with one 4A or 4B nodule. An expert panel re-evaluated the categories and determined the reference standard. Nineteen radiologists were asked to determine the presence of CT features of malignancy and 4X categorization for each nodule. A review was performed in two sessions, and training material was given after session 1. Agreement on 4X categorization between radiologists and the expert-adjudicated reference standard and agreement between radiologist-assessed 4X categorization and lung cancer diagnosis were evaluated. RESULTS: The 48 expert-adjudicated 4X nodules and 64 non-4X nodules were evenly distributed in each session. The proportion of category 4X decreased after training (56.4% ± 16.9% vs. 33.4% ± 8.0%; p < 0.001). Cohen's κ indicated poor agreement (0.39 ± 0.16) in session 1, but agreement improved in session 2 (0.47 ± 0.09; p = 0.03). The increase in agreement in session 2 was observed among inexperienced radiologists (p < 0.05), and experienced and inexperienced reviewers exhibited comparable agreement performance in session 2 (p > 0.05). All agreement measures between radiologist-assessed 4X categorization and lung cancer diagnosis increased in session 2 (p < 0.05). CONCLUSION: Radiologist training can improve reader agreement on 4X categorization, leading to enhanced diagnostic performance for lung cancer. KEY POINTS: • Agreement on 4X categorization between radiologists and an expert-adjudicated reference standard was initially poor, but improved significantly after training. • The mean proportion of 4X categorization by 19 radiologists decreased from 56.4% ± 16.9% in session 1 to 33.4% ± 8.0% in session 2. • All agreement measures between the 4X categorization and lung cancer diagnosis increased significantly in session 2, implying that appropriate training and guidance increased the diagnostic potential of category 4X.

Quantitative ultrasound radiofrequency data analysis for the assessment of hepatic steatosis using the controlled attenuation parameter as a reference standard.

PURPOSE: This study was aimed to investigate the value of quantitative ultrasound (US) parameters from radiofrequency (RF) data analysis for assessing hepatic steatosis, using controlled attenuation parameter (CAP)-based steatosis grades as the reference standard. METHODS: We analyzed 243 participants with both B-mode liver US with RF data acquisition and CAP measurements. On B-mode US images, hepatic steatosis was visually scored (0/1/2/3, none/mild/moderate/severe), and the hepatorenal index (HRI) was calculated. From the RF data analysis, the tissue scatter-distribution imaging parameter (TSI-p) and tissue attenuation imaging parameter (TAI-p) of the liver parenchyma were measured. US parameters were correlated with CAP-based steatosis grades (S0/1/2/3, none/mild/moderate/severe) and their diagnostic performance was evaluated using receiver operating characteristic (ROC) curve analysis. Multivariate linear regression analysis was performed to identify determinants of TSI-p and TAI-p. RESULTS: Participants were classified as having S0 (n=152), S1 (n=54), S2 (n=14), and S3 (n=23) on CAP measurements. TSI-p and TAI-p were significantly correlated with steatosis grades (ρ =0.593 and ρ=-0.617, P<0.001 for both). For predicting ≥S1, ≥S2, and S3, the areas under the ROC curves (AUCs) of TSI-p were 0.827/0.914/0.917; TAI-p, 0.844/0.914/0.909; visual scores, 0.659/0.778/0.794; and HRI, 0.629/0.751/0.759, respectively. TSI-p and TAI-p had significantly higher AUCs than did visual scores or HRI for ≥S1 or ≥S2 (P≤0.003). In the multivariate analysis, the transient elastography-based fibrosis grade (P=0.034) and steatosis grade (P<0.001) were independent determinants of TSI-p, while steatosis grade (P<0.001) was an independent determinant of TAI-p. CONCLUSION: TSI-p and TAI-p derived from US RF data may be useful for detecting hepatic steatosis and assessing its severity.

Assessment of hepatic sinusoidal obstruction syndrome with intravoxel incoherent motion diffusion-weighted imaging: An experimental study in a rat model.

BACKGROUND: Intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) parameters may reflect perfusion and diffusion changes in hepatic sinusoidal obstruction syndrome (SOS). PURPOSE: To investigate the feasibility of IVIM-DWI in the noninvasive assessment of hepatic SOS in an experimental rat model. STUDY TYPE: Animal study. POPULATION/SUBJECTS: Forty-four rats were administered different doses (90 or 160 mg/kg) of monocrotaline by gavage either 48 or 72 hours before MRI to induce different degrees of hepatic SOS, and another 10 rats served as controls. FIELD STRENGTH/SEQUENCE: 3T scanner, IVIM-DWI using nine b values (0-800 sec/mm2 ). ASSESSMENT: Histologically, rats were classified as having none (n = 10), mild (n = 8), moderate (n = 19), or severe SOS (n = 17). The apparent diffusion coefficient (ADC) and IVIM-derived parameters (D: true diffusion coefficient, D*: pseudo-diffusion coefficient, and f: perfusion fraction) of the liver parenchyma were measured. STATISTICAL TESTS: IVIM-DWI parameters were compared according to histologic grades of SOS (none, mild, moderate, and severe), and receiver operating characteristic (ROC) curve analysis was performed to determine the diagnostic accuracy. RESULTS: ADC, D, and f of the liver parenchyma were significantly different according to SOS severity groups (Ps < 0.01) and significantly decreased as SOS severity increased (rho = -0.323, -0.313, and -0.700; P = 0.017, 0.021, and <0.001, respectively). Means of f in none, mild, moderate, and severe SOS were 17.2%, 13.3%, 12.3%, and 11.1%, respectively. Among ADC and IVIM-derived parameters, f provided the highest area under the ROC curves for detecting ≥mild, ≥moderate, and severe SOS (0.991, 0.890, and 0.803, respectively). DATA CONCLUSION: IVIM-DWI may be useful in the diagnosis and severity assessment of hepatic SOS. LEVEL OF EVIDENCE: 2 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:81-89.

Prognostic value of MRI in assessing extramural venous invasion in rectal cancer: multi-readers' diagnostic performance.

OBJECTIVES: This study was conducted in order to determine the prognostic value of MRI for extramural venous invasion (EMVI) in rectal cancer compared to pathology and to assess the diagnostic performance of multireaders. METHODS: We retrospectively enrolled 222 patients (M:F = 148:74; mean age ± standard deviation, 61.5 ± 12 years) with histopathologically proven rectal cancers who underwent preoperative MRI between 2007 and 2016. Among them, 74 patients had positive EMVI on pathology (pEMVI) and 148 patients had negative pEMVI. Three radiologists with 7 (reviewer 1), 3 (reviewer 2), and 1 (reviewer 3) year of experience in rectal MR imaging determined the presence of EMVI on MRI (mrEMVI) using a 5-point grading system. Using histopathologic results as the reference standard, radiologists' performances were analyzed and compared with receiver operating characteristic (ROC) analysis. For assessment of interobserver variation, intraclass correlation coefficients (ICC) were used. Lastly, Kaplan-Meier estimation and Cox proportional hazard models were used for survival analysis. RESULTS: The area under the ROC curve (AUC) was highest in reviewer 1 (0.829), followed by reviewer 2 (0.798) and reviewer 3 (0.658). Differences in AUCs between reviewer 1 or 2 and reviewer 3 were statistically significant (p < 0.001). ICC was substantial between reviewers 1 and 2. Overall survival (OS) was significantly different according to the positive circumferential resection margin, adjuvant treatment, and the presence of mrEMVI, but not by the presence of pEMVI. CONCLUSIONS: For experienced radiologists, the diagnostic performance of mrEMVI was good, resulting in better prediction of OS than with pEMVI, with substantial interobserver agreement. KEY POINTS: • When read by experienced radiologists, MR can provide reliable diagnostic performance in assessing EMVI for patients with rectal cancer. • Positive mrEMVI is an adverse prognostic factor of overall survival and may influence the clinical decision-making.

Validation of prediction models for risk stratification of incidentally detected pulmonary subsolid nodules: a retrospective cohort study in a Korean tertiary medical centre.

OBJECTIVES: To validate the performances of two prediction models (Brock and Lee models) for the differentiation of minimally invasive adenocarcinoma (MIA) and invasive pulmonary adenocarcinoma (IPA) from preinvasive lesions among subsolid nodules (SSNs). DESIGN: A retrospective cohort study. SETTING: A tertiary university hospital in South Korea. PARTICIPANTS: 410 patients with 410 incidentally detected SSNs who underwent surgical resection for the pulmonary adenocarcinoma spectrum between 2011 and 2015. PRIMARY AND SECONDARY OUTCOME MEASURES: Using clinical and radiological variables, the predicted probability of MIA/IPA was calculated from pre-existing logistic models (Brock and Lee models). Areas under the receiver operating characteristic curve (AUCs) were calculated and compared between models. Performance metrics including sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were also obtained. RESULTS: For pure ground-glass nodules (n=101), the AUC of the Brock model in differentiating MIA/IPA (59/101) from preinvasive lesions (42/101) was 0.671. Sensitivity, specificity, accuracy, PPV and NPV based on the optimal cut-off value were 64.4%, 64.3%, 64.4%, 71.7% and 56.3%, respectively. Sensitivity, specificity, accuracy, PPV and NPV according to the Lee criteria were 76.3%, 42.9%, 62.4%, 65.2% and 56.3%, respectively. AUC was not obtained for the Lee model as a single cut-off of nodule size (≥10 mm) was suggested by this model for the assessment of pure ground-glass nodules. For part-solid nodules (n=309; 26 preinvasive lesions and 283 MIA/IPAs), the AUC was 0.746 for the Brock model and 0.771 for the Lee model (p=0.574). Sensitivity, specificity, accuracy, PPV and NPV were 82.3%, 53.8%, 79.9%, 95.1% and 21.9%, respectively, for the Brock model and 77.0%, 69.2%, 76.4%, 96.5% and 21.7%, respectively, for the Lee model. CONCLUSIONS: The performance of prediction models for the incidentally detected SSNs in differentiating MIA/IPA from preinvasive lesions might be suboptimal. Thus, an alternative risk calculation model is required for the incidentally detected SSNs.

Chemoembolisation for hepatocellular carcinoma with bile duct invasion: is preprocedural biliary drainage mandatory?

PURPOSE: To determine the necessity of preprocedural biliary drainage prior to chemoembolisation for hepatocellular carcinoma (HCC) with bile duct invasion. MATERIALS AND METHODS: The study included 52 patients who received chemoembolisation for unresectable HCC invading bile duct and causing hyperbilirubinemia (>3 mg/dL). Patients were divided into three groups according to biliary drainage and its effect: effective drainage (n=21), ineffective drainage (n=17), and non-drainage (n=14). Thirty-day mortality, length of hospitalisation, adverse events recorded using Common Terminology Criteria for Adverse Events (CTCAE), survival, and tumour response was compared among three groups. RESULTS: Thirty-day mortality rates were 14.3% (n=3), 17.6% (n=3), and 7.1% (n=1) for effective, ineffective, and non-drainage groups, respectively, and did not differ significantly among groups (p=0.780). The mean length of hospitalisation was shorter in non-drainage group compared to ineffective drainage group (12.1±11.4 vs 34.1±29.6 days, p=0.012). Mean differences in CTCAE grade for laboratory parameters before and after chemoembolisation were not significantly different among three groups. Survival among three groups was not significantly different (p=0.239-0.825). The tumour response was also not significantly different among three groups (p=0.679). CONCLUSION: Biliary drainage may not be mandatory prior to chemoembolisation in patients with HCC invading the bile duct. KEY POINTS: • Chemoembolisation without biliary drainage can be performed for icteric HCC. • Chemoembolisation without biliary drainage is not accompanied by increased adverse events. • Preprocedural biliary drainage may not be mandatory for chemoembolisation for icteric HCC.

Advanced virtual monochromatic reconstruction of dual-energy unenhanced brain computed tomography in children: comparison of image quality against standard mono-energetic images and conventional polychromatic computed tomography.

BACKGROUND: Advanced virtual monochromatic reconstruction from dual-energy brain CT has not been evaluated in children. OBJECTIVE: To determine the most effective advanced virtual monochromatic imaging energy level for maximizing pediatric brain parenchymal image quality in dual-energy unenhanced brain CT and to compare this technique with conventional monochromatic reconstruction and polychromatic scanning. MATERIALS AND METHODS: Using both conventional (Mono) and advanced monochromatic reconstruction (Mono+) techniques, we retrospectively reconstructed 13 virtual monochromatic imaging energy levels from 40 keV to 100 keV in 5-keV increments from dual-source, dual-energy unenhanced brain CT scans obtained in 23 children. We analyzed gray and white matter noise ratios, signal-to-noise ratios and contrast-to-noise ratio, and posterior fossa artifact. We chose the optimal mono-energetic levels and compared them with conventional CT. RESULTS: For Mono+maximum optima were observed at 60 keV, and minimum posterior fossa artifact at 70 keV. For Mono, optima were at 65-70 keV, with minimum posterior fossa artifact at 75 keV. Mono+ was superior to Mono and to polychromatic CT for image-quality measures. Subjective analysis rated Mono+superior to other image sets. CONCLUSION: Optimal virtual monochromatic imaging using Mono+ algorithm demonstrated better image quality for gray-white matter differentiation and reduction of the artifact in the posterior fossa.

Value of Nonrigid Registration of Pre-Procedure MR with Post-Procedure CT After Radiofrequency Ablation for Hepatocellular Carcinoma.

PURPOSE: To evaluate the value of pre-radiofrequency ablation (RFA) MR and post-RFA CT registration for the assessment of the therapeutic response of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: A total of 178 patients with single HCC who received RFA as an initial treatment and had available pre-RFA MR and post-RFA CT images were included in this retrospective study. Two independent readers (one experienced radiologist, one inexperienced radiologist) scored the ablative margin (AM) of treated tumors on a four-point scale (1, residual tumor; 2, incomplete AM; 3, borderline AM; 4, sufficient AM), in two separate sessions: (1) visual comparison between pre-and post-RFA images; (2) with addition of nonrigid registration for pre- and post-RFA images. Local tumor progression (LTP) rates between low-risk (response score, 3-4) and high-risk groups (1-2) were analyzed using the Kaplan-Meier method at each interpretation session. RESULTS: The patients' reassignments after using the registered images were statistically significant for inexperienced reader (p < 0.001). In the inexperienced reader, LTP rates of low- and high-risk groups were significantly different with addition of registered images (session 2) (p < 0.001), but not significantly different in session 1 (p = 0.101). However, in the experienced reader, LTP rates of low- and high-risk groups were significantly different in both interpretation sessions (p < 0.001). Using the registered images, the cumulative incidence of LTP at 2 years was 3.0-6.6%, for the low-risk group, and 18.6-27.8% for the high-risk group. CONCLUSION: Registration between pre-RFA MR and post-RFA CT images may allow better assessment of the therapeutic response of HCC after RFA, especially for inexperienced radiologists, helping in the risk stratification for LTP.

Persistent part-solid nodules with solid part of 5 mm or smaller: Can the 'follow-up and surgical resection after interval growth' policy have a negative effect on patient prognosis?

OBJECTIVE: To investigate whether "follow-up and surgical resection after interval growth" can negatively influence recurrence or mortality in patients with persistent part-solid nodules (PSNs) with solid components ≤5 mm. METHODS: One hundred twenty five surgically resected persistent PSNs with solid components ≤5 mm in 125 individuals were evaluated. Of the 125 PSNs, 54 and 71 PSNs were categorized into interval growth and immediate surgery groups, respectively. Cox regression analysis was performed to evaluate the association of "follow-up until interval growth" with recurrence and survival, adjusted for initial clinical and CT features. RESULTS: In the interval growth group, 30 patients showed increased nodule size, 10 increased solid parts, and the remaining 14 both patterns. Five patients showed clinical stage shifts (stage T1a, initially, to T1b after interval growth). Post-operative disease recurrence occurred in six individuals (interval growth group, n = 2/54; immediate surgery group, n = 4/71), and four individuals died (interval growth group, n = 1/54; immediate surgery group, n = 3/71). There were no significant differences between these two groups in terms of recurrence-free survival (p = 0.451) and overall survival (p = 0.185). CONCLUSION: "Follow-up and surgical resection after interval growth" did not negatively influence the prognosis of patients with persistent PSNs with solid components ≤5 mm. KEY POINTS: • Incidences of post-operative recurrence or death in patients with PSN are low. • "Follow-up until interval growth" of PSNs does not negatively influence disease recurrence. • There was no survival disadvantage related with "follow-up until interval growth" in PSNs.