Radiation Major Hepatectomy Using Ablative Dose Yttrium-90 Radioembolization in Patients with Hepatocellular Carcinoma 5 cm or Larger.

PURPOSE: To evaluate the safety and effectiveness of ablative radioembolization for large hepatocellular carcinoma (HCC) while preserving a small future liver remnant (FLR). MATERIALS AND METHODS: Twenty-five patients with large HCC of ≥5 cm requiring treatment for >60% of the total liver volume and having well-preserved liver function were treated with ablative glass microsphere radioembolization at a single institution from January 2017 to December 2021. Radioembolization was performed with a mean absorbed dose of >150 Gy, and the FLR per nontumor liver volume (NTLV) was set at >30%. Changes in liver function, adverse events, duration of response (DoR) in a treated area, time-to-progression (TTP), and overall survival (OS) were retrospectively investigated. RESULTS: The largest tumor diameter and planned dose per treated volume were 11.4 cm ± 3.9 and 242.3 Gy ± 63.6 (169.4 Gy ± 45.9 per whole liver volume), respectively. All patients remained at Child-Pugh Class A for 90 days. No patient experienced Grade 3‒4 hyperbilirubinemia or new ascites. One patient (lung dose, 27.8 Gy) developed radiation pneumonitis requiring transient steroid treatment. According to the posttreatment dosimetry, the tumorous and nontumorous liver absorbed doses were 418.8 Gy ± 227.4 and 69.0 Gy ± 32.1, respectively. The median DoR in a treated area and TTP were 22.0 and 17.1 months, respectively. The 5-year OS rate was 83.2%. CONCLUSIONS: Ablative radioembolization of large HCC of ≥5 cm can be performed safely and effectively in patients with preserved liver function when FLR/NTLV exceeds 30%.

Mechanism of action of genicular artery embolization in a rabbit model of knee osteoarthritis.

OBJECTIVES: To establish a rabbit osteoarthritis model for genicular artery embolization (GAE) experiments and to investigate the cellular mechanism of action of this novel procedure for interventional radiologists. METHODS: Rabbit knee osteoarthritis was surgically modeled by anterior cruciate ligament transection and medial partial meniscectomy of the bilateral hindlimbs followed by 10 weeks of incubation. Rabbits exhibiting synovitis on magnetic resonance imaging were randomly divided into two groups: the bilateral GAE group and the control (sham procedure) group. Four weeks later, the rabbits' mobility (moving time, sec/10 min) and the histopathological features of each knee were assessed, and inter-group differences were evaluated using Student's t-test and ordinal/linear logistic models with generalized estimating equations. RESULTS: Osteoarthritis modeling and endovascular procedures were successful in 15 of 20 rabbits (8 and 7 in the GAE and control groups, respectively). There was no significant difference in moving times between the two groups (p = .958). The degree of structural cartilage damage was similar in both groups (p = .780). However, the synovial proliferation (p = .016), synovial hypertrophy (p < .001), and villous hyperplasia of the synovial stroma (p = .002) scores were significantly lower in the GAE group than in the control group. The CD3+ cell density (p = .018) and CD3 + cell-infiltrated area (p = .019) were also significantly lower in the GAE group than in the control group. CONCLUSION: GAE can limit inflammatory processes in the synovium of osteoarthritis-affected knees. KEY POINTS: Surgical transection of the anterior cruciate ligament and medial partial meniscectomy of rabbit knees provides a useful animal model for research of genicular artery embolization. Osteoarthritic knees treated by genicular artery embolization showed milder synovial proliferation (p = .016), synovial hypertrophy (p < .001), and villous hyperplasia of the synovial stroma (p = .002) than the untreated knees. Osteoarthritic knees treated by genicular artery embolization presented lower CD3+ cell density (p = .018) and CD3+ cell-infiltrated area (p = .019) in the synovium than the untreated knees.

Safety of Radioembolization via the Cystic Artery in Patients with Hepatocellular Carcinoma and Parasitized Arterial Supply.

PURPOSE: To evaluate the safety and effectiveness of radioembolization through the cystic artery supplying hepatocellular carcinoma (HCC) adjacent to the gallbladder. MATERIALS AND METHODS: This retrospective, single-center study included 24 patients who underwent radioembolization via the cystic artery between March 2017 and October 2022. The median tumor size was 8.3 cm (range, 3.4-20.4 cm). Twenty-two (92%) patients had Child-Pugh Class A disease, and 2 (8%) patients had Class B cirrhosis. Technical issues, adverse events, and tumor response were analyzed. RESULTS: Infusion of radioactive microspheres was performed from the main cystic artery (n = 6), the deep cystic artery (n = 9), and small feeders from the cystic artery (n = 9). The cystic artery supplied the primary index tumor in 21 patients. The median radiation activity delivered via the cystic artery was 0.19 GBq (range, 0.02-0.43 GBq). The median total radiation activity administered was 4.1 GBq (range, 0.9-10.8 GBq). There was no case of symptomatic cholecystitis requiring invasive intervention. One patient experienced abdominal pain during injection of radioactive microspheres via the cystic artery. Eleven (46%) patients received pain medication during or within 2 days of the procedure. Twelve (50%) patients had gallbladder wall thickening on a 1-month follow-up computed tomography scan. Based on follow-up imaging, 23 (96%) patients showed an objective response (complete or partial response) of the tumor supplied by the cystic artery. CONCLUSION: Radioembolization via the cystic artery may be safe in patients with HCC partially supplied by the cystic artery.

Ideal Size Range for Embolic Agents in Interventional Oncology Experiments Involving Rat Models of Hepatocellular Carcinoma.

PURPOSE: To optimize future translational research, this study aimed to determine the ideal range of sizes for embolic agents in interventional oncology experiments utilizing rat models of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Fifty-five male Sprague-Dawley rats were divided into 2 groups to evaluate the distribution of microparticles and tumor response rates. After implanting hepatoma cells into the rodent liver, fluorescent microparticles of sizes ranging from 5 to 35 µm were administered via the hepatic artery. In the first group, the distribution of microparticles was evaluated in hepatoma-free rats, and the tumor necrosis rates following administration of a predetermined aliquot of microparticles (0.4 mL) were measured in tumor-bearing rats. Thereafter, the 3 microparticle sizes associated with the best tumor response rates were chosen for analysis of the tumor necrosis rates following hepatic artery embolization until angiographic stasis is achieved in the second group. RESULTS: The tendency for microparticles to distribute in nontarget organs increased as the microparticle size decreased below 15 µm. Tumor necrosis rates tended to be higher in rats treated with 15-19-µm microparticles than in those treated with 19-24-µm or 19-24-µm microparticles. The in-group deviation of the tumor necrosis rates was highest for microparticle sizes of 19-24 and 25-35 µm, which implies the proximal embolization of the hepatic artery for larger microparticle sizes. However, there was no statistical significance among the 3 groups (P = .095). CONCLUSIONS: The 15-19-µm embolic agents were the most favorable for causing tumor necrosis without nontarget toxicity in the transarterial treatments of rat HCC models.

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.

Hepatocellular Carcinoma Supplied by the Inferior Phrenic Artery or Cystic Artery: Anatomic and Technical Considerations.

Intra-arterial treatment has been identified as one of the mainstays in the management of unresectable hepatocellular carcinoma. A thorough knowledge of tumor arterial supply enables selective therapy, which improves both safety and efficacy. The inferior phrenic artery (IPA) is the most common extrahepatic collateral artery that feeds hepatocellular carcinoma. The bilateral IPAs are known to have a specific vascular anatomy. A systemic-to-pulmonary shunt and a gastric branch from the IPAs may be present and should not be confused with tumor blush. The supraceliac aorta and celiac trunk are the common origin sites of the IPAs, and their orifice may be compressed by the diaphragm. Various techniques and catheters are used for catheterization of the IPAs, depending on their origin sites. Because the IPA is normally connected with the intercostal, internal mammary, retroperitoneal, and hepatic arteries, its hemodynamics may be altered when its orifice is occluded. In general, superselective chemoembolization via the target branch of the IPA is safe and effective. When a systemic-to-pulmonary shunt from the IPA is adequately embolized with coils or particles, radioembolization through the IPA can be performed safely in most cases. The cystic artery branches into deep and superficial cystic arteries; deep cystic arteries often supply tumors near the gallbladder. Chemoembolization through the cystic artery is relatively safe, with transient embolic materials. Radioembolization through the cystic artery has been recently tried, with acceptable efficacy and toxicity results, but it requires further investigation. ©RSNA, 2022.

C-Arm Computed Tomographic Image Fusion for Repetitive Transarterial Chemoembolization of Hepatocellular Carcinoma.

OBJECTIVE: The aim of this study was to evaluate the potential implications of fusion imaging with C-arm computed tomography (CACT) scans for repetitive conventional transarterial chemoembolization (cTACE) for hepatocellular carcinoma. MATERIALS AND METHODS: Fifty-six cTACE sessions were performed using fusion CACT images from September 2020 to June 2021 in a tertiary referral center, and the data were retrospectively analyzed. Fusion of unenhanced and enhanced CACT images was considered when previously accumulated iodized oil hampered the identification of local tumor progression or intrahepatic distant metastasis (indication A), when a tumor was supplied by multiple arteries with different origins from the aorta and missing tumor enhancement was suspected (indication B), or when iodized oil distribution on immediate post-cTACE CACT images needed to be precisely compared with the pre-cTACE images (indication C). Fusion image quality, initial tumor response, time to local progression (TTLP) of index tumors, and time to progression (TTP) were evaluated. RESULTS: The fusion quality was satisfactory with a mean misregistration distance of 1.4 mm. For the 40 patients with indication A, the initial tumor responses at 3 months were nonviable, equivocal, and viable in 27 (67.5%), 4 (10.0%), and 9 (22.5%) index tumors, respectively. The median TTLP and TTP were 14.8 months and 4.5 months, respectively. For 10 patients with indication B, the median TTLP and TTP were 8.3 months and 2.6 months, respectively. Among the 6 patients with indication C, 2 patients were additionally treated at the same cTACE session after confirming incomplete iodized oil uptake on fusion imaging. CONCLUSIONS: Fusion CACT images are useful in patients with hepatocellular carcinoma undergoing repetitive cTACE.

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.

A Motion Artifact Correction Algorithm for Cone-Beam CT in Patients with Hepatic Malignancies Treated with Transarterial Chemoembolization.

PURPOSE: To evaluate the effect of a motion artifact correction algorithm (MACA) on cone-beam computed tomography (CT) during transarterial chemoembolization for hepatic malignancies. MATERIALS AND METHODS: From June 2020 to March 2021, 42 patients with mild-to-severe motion artifacts detected using single cone-beam CT scans were evaluated retrospectively. The image quality of native and motion-corrected data was compared. The maximum intensity, sharpness, and full width at half maximum (FWHM) of 5 segmental hepatic arteries were quantitatively measured. The overall quality of maximum intensity projection (MIP) images, conspicuity of tumor-supplying arteries, and need for selective angiography to ascertain the vascular anatomy were qualitatively evaluated by multiple readers. Paired t and Wilcoxon signed rank tests were used to compare the parameters. RESULTS: The mean maximum intensity and sharpness increased from 2,792.01 HU ± 451.36 to 3,148.40 HU ± 594.46 and from 0.31 ± 0.02/mm to 0.34 ± 0.02/mm, respectively, using the MACA (both P < .001). The MACA decreased the mean FWHM from 2.02 mm ± 0.27 to 1.78 mm ± 0.26 (P < .001). The overall quality of the MIP images and the conspicuity of the tumor-supplying artery were enhanced from 2.5 to 3.0 points and from 3.0 to 4.0 points, respectively (both P < .001). Selective angiography was expected to be omitted in 7 cases (16.7%, 7/42) after using the MACA. CONCLUSIONS: The MACA significantly improved both quantitative and qualitative image quality of cone-beam CT in selected patients with motion artifacts during transarterial chemoembolization for hepatic malignancies.

Outcomes of Venoplasty-Assisted, Peripherally Inserted Central Catheter Placement in Patients with Upper-Arm Venous Stenosis: Comparison with Midlines and Contralateral Placement.

PURPOSE: To compare the effectiveness and safety of percutaneous transluminal angioplasty and peripherally inserted central catheter (PTA + PICC), contralateral PICC, and midline catheterization (MC) in patients with venous stenosis. MATERIALS AND METHODS: A total of 7,327 PICC procedures were performed in 5,421 patients at a single institution between 2013 and 2019. Among them, 87 patients had upper-arm venous stenoses and were managed with PTA + PICC, contralateral PICC, or MC. Data on catheter-dwell time, clinical success rate, and adverse events were recorded. The procedure was considered to have clinically succeeded when a PICC was removed from the patient just before discharge or after the completion of therapy. Catheter survival time and the chance of adverse events were compared among the groups using the Kaplan-Meier method and log-rank test. RESULTS: PTA + PICC, contralateral PICC, and MC procedures were performed for 57 (65.5%, 57/87), 10 (11.5%, 10/87), and 20 (23.0%, 23/87) patients, respectively. The mean catheter-dwell time in the PTA + PICC, contralateral PICC, and MC groups was 49.7, 28.7, and 15.1 days, respectively, and the clinical success rate of each group was 86.0% (49/57), 80.0% (8/10), and 50.0% (10/20). The PTA + PICC group had a significantly longer catheter survival time than the MC group (P < .001). The chance of a catheter-related infection (P = .008) was significantly lower in the PTA + PICC group than in the MC group. CONCLUSIONS: PTA + PICC or contralateral PICC should be considered prior to ipsilateral MC when venous stenosis is encountered during PICC procedures.

A Prognostic Prediction Model of Transarterial Radioembolization in Hepatocellular Carcinoma: SNAP-HCC.

BACKGROUND: Prognosis prediction in patient with hepatocellular carcinoma (HCC) after transarterial radioembolization (TARE) remains difficult. The aim of this study was to develop a prognostic model to aid in the decision to use TARE. METHODS: A total of 174 patients in Korea who underwent TARE for HCC as the initial treatment were included. We developed a prediction model for overall survival (OS) based on independent risk factors for OS and validated the model by bootstrap method. RESULTS: The median maximal size of the tumors was 8.2 cm, the median number of tumors was 2, and the median albumin level was 4.0 g/dL. Portal vein tumor thrombosis was found in 46.0% (Vp1-3 [39.7%] and Vp4 [6.3%]). Four independent risk factors associated with OS (maximal tumor size, tumor number, albumin, and portal vein tumor thrombosis) were used to develop the SNAP-HCC score. Bootstrap validation of the scoring index determined that the Harrell's c-index for OS was 0.756 (95% confidence interval: 0.729-0.783). Patients grouped based on their SNAP-HCC (scores 0-5) were well discriminated, with significant differences between the groups (all P < 0.05). Patients with SNAP-HCC < 3 showed significantly longer OS than patients with SNAP-HCC ≥ 3 (P < 0.001). The respective survival probabilities at years 1 and 3 were 0.81 and 0.73 in the low-risk (SNAP-HCC < 3) and 0.32 and 0.14 in the high-risk (SNAP-HCC ≥ 3) patients. CONCLUSIONS: The SNAP-HCC scoring system predicted the outcome of HCC patients undergoing TARE as an initial treatment. This model could be helpful for initial planning the treatment of HCC patients.

Dextroplantation of Left Liver Graft in Infants.

The position of the left side liver graft is important, and it could lead to complications of the hepatic vein (HV) and portal vein (PV), especially in a small child using a variant left lateral section (vLLS) graft. The purpose of this study was to evaluate the outcome of a novel technique for the implantation of a vLLS graft to the right side (dextroplantation) in infants. For 3 years, 10 consecutive infants underwent dextroplantation using a vLLS graft (group D). The graft was implanted to the right side of the recipient after 90° counterclockwise rotation; the left HV graft was anastomosed to inferior vena cava using the extended right and middle HV stump, and PV was reconstructed using oblique anastomosis without angulation. Surgical outcomes were compared with the historical control group (n = 17, group C) who underwent conventional liver transplantation using a vLLS during infancy. Group D recipients were smaller than group C (body weight <6 kg: 50.0% versus 11.8%; P = 0.03). The rate of graft-to-recipient weight ratio >4% was higher in group D (60.0%) than C (11.8%; P = 0.01). Surgical drains were removed earlier in group D than in group C (15 versus 18 postoperative days [PODs]; P = 0.048). Each group had 1 PV complication (10.0% versus 5.9%); no HV complication occurred in group D, but 3 HV complications (17.6%) occurred in group C (P > 0.05). Hospital stay was shorter in group D than in group C (20 versus 31 PODs; P = 0.02). Dextroplantation of a vLLS graft, even a large-for-size one, was successful in small infants without compromising venous outcomes, compared with conventional vLLS transplantation. We could remove the surgical drains earlier and reduce hospital stays in cases of dextroplantation.

Spectral CT-Based Iodized Oil Quantification to Predict Tumor Response Following Chemoembolization of Hepatocellular Carcinoma.

PURPOSE: To quantify iodized oil retention in tumors after transarterial chemoembolization using spectral computed tomography (CT) imaging in patients with hepatocellular carcinoma (HCC) and evaluate its performance in predicting 12-month tumor responses. MATERIALS AND METHODS: From September 2017 to December 2018, 111 patients with HCC underwent initial conventional transarterial chemoembolization. Immediately after the procedure, unenhanced CT was performed using a spectral CT scanner, and the iodized oil densities in index tumors were measured. In tumor-level analyses, a threshold level of iodized oil density in the tumors was calculated using clustered receiver operating characteristic curve analyses to predict the 12-month tumor responses. In patient-level analyses, significant factors associated with a 12-month complete response, including the presence of tumors below the threshold value (ie, suspected residual tumors), were evaluated by logistic regression. RESULTS: Forty-eight HCCs in 39 patients were included in the analyses. The lower 10th percentile of the iodine density was identified as the threshold for determining the 12-month nonviable responses. The area under the curve of the iodine density measurements in predicting the 12-month nonviable responses was 0.893 (95% confidence interval, 0.797-0.989). The threshold value of the iodine density of 10.68 mg/mL yielded a sensitivity of 82.76% and specificity of 94.74% (P < .001). In the patient-level analysis, the 12-month complete response was significantly associated with the presence of a suspected residual tumor, with an odds ratio of 72.0 (95% confidence interval, 7.273-712.770). CONCLUSIONS: Spectral CT imaging using quantitative analysis of the iodized oil retention in target HCCs can predict tumor responses after a conventional transarterial chemoembolization procedure.

LI-RADS treatment response categorization on gadoxetic acid-enhanced MRI: diagnostic performance compared to mRECIST and added value of ancillary features.

OBJECTIVES: This study was conducted in order to assess the performance of the Liver Imaging Reporting and Data System (LI-RADS) treatment response (TR) (LR-TR) categorization on gadoxetic acid-enhanced MRI (Gd-EOB-MRI) for detecting viable tumors in hepatocellular carcinoma (HCC) treated with locoregional treatment (LRT) and to investigate the added value of ancillary features (AFs) to conventional enhancement-based criteria. METHODS: This retrospective study included 183 patients with Gd-EOB-MRI after LRT for HCC and appropriate reference standards for tumor viability (84 viable and 99 nonviable). Two independent radiologists assigned per-lesion mRECIST and TR categories (TR-nonviable, TR-equivocal, or TR-viable) according to the LR-TR algorithm and modified LR-TR algorithms including mLR-TR(TP) allowing transitional phase (TP) washout and mLR-TR(AF) allowing category adjustment by applying AFs. Diagnostic performances of imaging criteria were compared using the Cochran's Q test with post hoc analysis. RESULTS: For detecting viable tumors, LR-TR-viable resulted in sensitivities of 64.5%/39.3% and specificities of 98.0%/98.0% in reviewers 1/2. In comparison to LR-TR-viable, mRECIST-viable, mLR-TR(TP)-viable, and mLR-TR(AF)-viable showed significantly higher sensitivities (92.9%/94.0%, 77.4%/56.6%, and 86.9%/83.3% in reviewers 1/2) (ps < 0.001). The specificity of mRECIST-viable (73.7%/62.6%) was significantly lower than that of LR-TR-viable (ps < 0.001), while those of mLR-TR(TP)-viable and mLR-TR(AF)-viable were greater than 95% (98.0%/96.0% and 97.0%/96.0%), statistically equivalent to LR-TR-viable (ps > 0.05). TR-equivocal was least assigned on mLR-TR(AF) (1.1%/7.7%) than LR-TR (15.8%/32.2%) or mLR-TR(TP) (6.6%/23.5%) in both reviewers. CONCLUSION: The LR-TR algorithm on Gd-EOB-MRI provides a specific diagnosis of viable tumor but with limited sensitivity. By applying AFs in the category adjustment, more sensitive and confident diagnosis can be achieved without significant loss of specificity. KEY POINTS: • The LI-RADS treatment response (LR-TR) algorithm on Gd-EOB-MRI provides a highly specific diagnosis of viable HCC but with limited sensitivity. • The inferior sensitivity of LR-TR-viable category to that of mRECIST can be improved by applying ancillary features in the category adjustment.

Benign Biliary Stricture after Yttrium-90 Radioembolization for Hepatocellular Carcinoma.

PURPOSE: To determine the frequency and possible causative factors of benign biliary stricture after radioembolization in patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: This retrospective study comprised 232 patients with HCC who underwent yttrium-90 radioembolization between October 2015 and September 2019. Benign biliary stricture was defined as biliary ductal dilatation of segmental or lobar biliary ducts on follow-up images. Clinical and radiologic characteristics were compared using χ2 test or independent t test. RESULTS: Mean target perfused tissue dose was 224.6 Gy ± 106.8 (median, 205.7 Gy; range, 47.0-694.7 Gy). Of 232 patients, 15 (6.5%) had benign biliary stricture, which was detected from 3 weeks to 10.3 months (mean, 3.9 months; median, 3.2 months). Whereas 5 patients did not have any symptoms or signs associated with benign biliary stricture, 10 patients had cholangitis and/or laboratory abnormality requiring biliary drainage procedures and intravenous antibiotic therapy. Selective radioembolization through a caudate artery was performed in 55 (23.7%) patients. The incidence of benign biliary stricture was 16.4% (9/55) and 3.4% (6/177) in patients with and without selective radioembolization through a caudate artery, respectively (P = .002). CONCLUSIONS: Benign biliary stricture following yttrium-90 radioembolization may be common among patients receiving selective treatment via a caudate artery.

Iatrogenic Arterioportal Fistula Caused by Radiofrequency Ablation of Hepatocellular Carcinoma: Clinical Course and Treatment Outcomes.

PURPOSE: To analyze the clinical course and treatment outcomes of patients with iatrogenic arterioportal fistula (APF) caused by radiofrequency (RF) ablation of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Among the 1,620 hepatocellular carcinoma patients treated by RF ablation between January 2012 and August 2017, 99 who developed APF after RF ablation were included in this retrospective study. Depending on the extent of portal vein enhancement on arterial phase images, APF was classified as massive or nonmassive. The patients' clinical course was investigated and statistically evaluated by univariable and multivariable analyses. RESULTS: Thrombocytopenia (odds ratio [OR] = 3.939; 95% confidence interval [CI], 1.141-13.598) was the only risk factor for developing massive APF. Eleven patients underwent embolotherapy (technical success rate, 90.9%) and no patients experienced serious adverse events within 30 days of the procedure. Patients with massive APF (66.7%) had a significantly higher chance of a Child-Pugh score increase than did the patients with nonmassive APF (13.6%) (P < .001). Massive APF had a significantly lower chance of natural regression than did nonmassive APF (P < .001). Child-Pugh B (OR = 17.739; 95% confidence interval, 2.361-133.279) and massive APF without treatment (OR = 11.061; 95% confidence interval, 1.257-97.341) were independent risk factors for liver failure that led to death of liver transplant within 1 year after RF ablation. CONCLUSIONS: Massive APF caused by RF ablation is mostly irreversible and significantly worsens patients' outcomes, but may be effectively treated with embolotherapy.

Spectral CT Imaging-Based Quantification of Iodized Oil Retention following Chemoembolization: Phantom and Animal Studies.

PURPOSE: To evaluate accuracy of iodine quantification using spectral CT and the potential of quantitative iodized oil analysis as an imaging biomarker of chemoembolization. MATERIALS AND METHODS: A phantom of an artificial liver with 6 artificial tumors containing different amounts of iodized oil (0-8 vol%) was scanned by spectral CT, and iodized oil density (mg/mL) and Hounsfield unit (HU) values were measured. In addition, VX2 hepatoma was induced in 23 rabbits. After chemoembolization using iodized oil chemoemulsion, the rabbits were scanned by spectral CT. The accumulation of iodized oil in the tumor was quantified in terms of iodized oil density and HUs, and the performances in predicting a pathologic complete response (CR) were evaluated by receiver operating characteristic curve analyses. RESULTS: The mean difference between true iodine densities and spectral image-based measurements was 0.5 mg/mL. Mean HU values were highly correlated with mean iodine density (r2 = 1.000, P < .001). In the animal study, a pathologic CR was observed in 17 of 23 rabbits (73.9%). The range of area under the curve values of iodine and HU measurements was 0.863-0.882. A tumoral iodine density of 3.57 mg/mL, which corresponds to 0.7 vol% iodized oil in the tumor, predicted a pathologic CR with a sensitivity of 70.6% and a specificity of 100.0%. CONCLUSIONS: Spectral CT imaging has a potential to predict tumor responses after chemoembolization by quantitatively assessing iodized oil in targets.

The Value of Preprocedural MR Imaging in Genicular Artery Embolization for Patients with Osteoarthritic Knee Pain.

PURPOSE: To determine the value of preprocedural MR imaging in genicular artery embolization (GAE) for patients with osteoarthritic knee pain. MATERIALS AND METHODS: This single-center study retrospectively analyzed 28 knees in 18 patients who underwent GAE for intractable knee pain < 1 month after MR imaging. The pain experienced in each knee was evaluated on a 100-mm visual analog scale (VAS) at baseline and 1- and 3-month after GAE. "GAE responders" were defined as knees that exhibited greater than 30% reduction of VAS pain scores from baseline at both follow-up visits. Musculoskeletal radiologists evaluated MR images of the affected knee compartment regarding cartilage defects, osteophytes, subchondral cysts, bone marrow lesions (BMLs), meniscal injury, and joint effusion. The performances of Kellgren-Lawrence (KL) grading and MR findings in predicting GAE responders was estimated based on receiver operating characteristic curves. RESULTS: The mean VAS pain score was 84.3 mm. BML (area under the curve [AUC], 0.860; P < .001), meniscal injury (AUC, 0.811; P = .003), and KL grading (AUC, 0.898; P < .001) were significantly associated with GAE outcome. To predict GAE responders, KL grade ≤ 2 yielded a sensitivity of 87.5% and a specificity of 60.9%, BML grade ≤ 1 yielded a sensitivity of 75.0% and a specificity of 69.6%, and meniscal injury grade ≤ 2 yielded a sensitivity of 83.3% and a specificity of 72.7%. CONCLUSIONS: Large BMLs and severe meniscal injuries on MR imaging, as well as high KL grades, indicated poor responses to GAE.

Feasibility of Boosted Radioembolization for Hepatocellular Carcinoma Larger than 5 cm.

PURPOSE: To address the feasibility of yttrium-90 (90Y) glass microspheres administered at a boosted dose in large hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: From July 2016 to August 2017, 20 patients who underwent 90Y radioembolization for treatment-naïve HCC met the following inclusion criteria: (i) nodular tumor, (ii) tumor size > 5 cm, (iii) Barcelona Clinic Liver Cancer stage A/B disease, (iv) target perfused tissue dose > 150 Gy, and (v) all tumors treated in 1 session of radioembolization. Follow-up radiologic findings and clinical outcomes were retrospectively reviewed until May 2018. Tumor response was determined per modified Response Evaluation Criteria In Solid Tumors. RESULTS: Mean total radiation activity infused was 4.96 GBq ± 1.82 (median, 4.88 GBq; range, 1.63-9.15 GBq). Mean target perfused tissue dose was 263.5 Gy ± 95.2 (median, 241.6 Gy; range, 156.2-550.6 Gy). The mean number of vials used per treatment was 4.15 ± 1.4 (median, 4; range, 2-7). Complete response rates were 25% at 1 month and 60% at 3 months. Complete response of the primary index tumor was achieved in 16 patients (80%) based on best tumor response. Local progression-free survival and progression-free survival rates were 94.1% and 85.0% at 6 mo and 94.1% and 74.7% at 1 year, respectively. Four patients (20%) had symptomatic (n = 3) or asymptomatic (n = 1) benign biliary strictures. CONCLUSIONS: Radioembolization with a boosted dose in patients with large HCCs may show favorable tumor response, but with considerable biliary complications.