Learning curve of liver stiffness measurement using a new hybrid machine composed of transient elastography interfaced with ultrasound.

OBJECTIVES: To assess the learning curve for performing reliable liver stiffness measurements using a new hybrid machine composed of transient elastography (TE) interfaced with an ultrasound device for radiographers and radiologists with different levels of expertise in ultrasound imaging. METHODS: Ten novice operators who had never performed TE measurements were prospectively evaluated from April to October 2018: senior radiologists, young radiologists, fellows, radiographers, and residents, with different levels of experience in abdominal ultrasound imaging. All operators had a short theoretical training followed by a training session under supervision in three patients. Then, each operator had to perform TE in 50 consecutive patients with chronic liver disease, using beforehand ultrasound examination to select measurement area in the right liver lobe, and if needed, the XL probe. Percentages of failures and reliable measurements were compared. RESULTS: The rates of failures of measurements, poorly reliable, reliable, and very reliable results, were of 4.2% (21/500), 2.4% (12/500), 47.6% (238/500), and 45.8% (229/500), respectively. The rates of reliable plus very reliable results were excellent, ranging from 91 to 96% among all the subgroups. The rates of very reliable, reliable, and unreliable results did not differ between operator subgroups and especially between junior radiologists, senior radiologists, and radiographers. No breaking point was observed in the interquartile range/median values over time. CONCLUSION: TE interfaced with ultrasound in this hybrid machine presents no learning curve effect. After a short initial training session, a novice observer is able to perform high rates of reliable and very reliable TE measurements. KEY POINTS: • When performing liver stiffness measurements using a new hybrid machine composed of transient elastography interfaced with ultrasound, the rate of failures of measurements is very low, below 5%. • After a short training session and using ultrasound planning, a novice operator, whatever its expertise in ultrasound imaging, is capable of performing high rates of reliable and very reliable measurements. • No learning curve is needed for performing reliable liver stiffness measurements using this new hybrid machine.

Percutaneous thermal ablation of hepatocellular carcinomas located in the hepatic dome using artificial carbon dioxide pneumothorax: retrospective evaluation of safety and efficacy.

INTRODUCTION: The targeting of hepatocellular carcinomas (HCC) in the hepatic dome can be challenging during percutaneous thermal ablation (PTA). The aims of this study were (1) to evaluate the safety and efficacy of PTA of HCC in the hepatic dome that cannot be visualized under US, using artificial CO2 pneumothorax and CT-guidance and (2) to compare the results with US-visible HCC located in the liver dome treated under US-guidance. MATERIALS: Over a 32-month period, 56 HCC located in the hepatic dome were extracted from a prospectively maintained database. Twenty-eight cases (US-guidance group) were treated under US-guidance, while the others (n = 28, CT-CO2 group) were treated under CT-guidance using artificial CO2 pneumothorax after lipiodol tagging of the tumor. The primary technical success and complications rates of this technique were retrospectively assessed. Local tumor progression (LTP), intrahepatic distant recurrence (IDR), local recurrence-free survival (LRFS) and overall survival (OS) were also compared between both groups. RESULTS: Primary technical success was 100% in both groups. No major complications occurred. After a median follow-up of 13.8 months (range, 1-33.4 months), LTP occurred in 10.7% (3/28) in CT-CO2 vs. 25% (7/28) in the US-guidance group (p = NS). IDR occurred in 39.3% (11/28) in CT-CO2 vs. 28.6% (8/28) in the US-guidance group (p = NS). Death occurred in 17.9% (5/28) of patients in both groups. LRFS and OS did not significantly differ using Kaplan-Meier survival estimates. CONCLUSION: CT-guided PTA after artificially induced CO2 pneumothorax is a safe and efficient technique to treat HCC located in the hepatic dome.

Simultaneous trans-hepatic portal and hepatic vein embolization before major hepatectomy: the liver venous deprivation technique.

PURPOSE: To assess technical feasibility, safety, and efficacy of the liver venous deprivation (LVD) technique that combines both portal and hepatic vein embolization during the same procedure for liver preparation before major hepatectomy. MATERIALS AND METHODS: Seven patients (mean age:63.6y[42-77y]) underwent trans-hepatic LVD for liver metastases (n = 2), hepatocellular carcinoma (n = 1), intrahepatic cholangiocarcinoma (n = 3) and Klatskin tumour (n = 1). Assessment of future remnant liver (FRL) volume, liver enzymes and histology was performed. RESULTS: Technical success was 100 %. No complication occurred before surgery. Resection was performed in 6/7 patients. CT-scan revealed hepatic congestion in the venous-deprived area (6/7 patients). A mean of 3 days (range: 1-8 days) after LVD, transaminases increased (AST: from 42 ± 24U/L to 103 ± 118U/L, ALT: from 45 ± 25U/L to 163 ± 205U/L). Twenty-three days (range: 13-30 days) after LVD, FRL increased from 28.2 % (range: 22.4-33.3 %) to 40.9 % (range: 33.6-59.3 %). During the first 7 days, venous-deprived liver volume increased (+13.4 %) probably reflecting vascular congestion, whereas it strongly decreased (-21.3 %) at 3-4 weeks. Histology (embolized lobe) revealed sinusoidal dilatation, hepatocyte necrosis and important atrophy in all patients. CONCLUSION: Trans-hepatic LVD technique is feasible, well tolerated and provides fast and important hypertrophy of the FRL. This new technique needs to be further evaluated and compared to portal vein embolization. KEY POINTS: • Twenty-three days after LVD, FRL increased from 28.2 % (range:22.4-33.3 %) to 40.9 % (range:33.6-59.3 %) • During the first 7 days, venous-deprived liver volume increased (+13.4 %) • Venous-deprived liver volume strongly decreased (mean atrophy:229 cc; -21.3 %) at 3-4 weeks • Histology of venous-deprived liver revealed sinusoidal dilatation, hepatocyte necrosis and important atrophy.

Intravoxel incoherent motion diffusion-weighted imaging in the liver: comparison of mono-, bi- and tri-exponential modelling at 3.0-T.

PURPOSE: To determine whether a mono-, bi- or tri-exponential model best fits the intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) signal of normal livers. MATERIALS AND METHODS: The pilot and validation studies were conducted in 38 and 36 patients with normal livers, respectively. The DWI sequence was performed using single-shot echoplanar imaging with 11 (pilot study) and 16 (validation study) b values. In each study, data from all patients were used to model the IVIM signal of normal liver. Diffusion coefficients (Di ± standard deviations) and their fractions (fi ± standard deviations) were determined from each model. The models were compared using the extra sum-of-squares test and information criteria. RESULTS: The tri-exponential model provided a better fit than both the bi- and mono-exponential models. The tri-exponential IVIM model determined three diffusion compartments: a slow (D1 = 1.35 ± 0.03 × 10(-3) mm(2)/s; f1 = 72.7 ± 0.9 %), a fast (D2 = 26.50 ± 2.49 × 10(-3) mm(2)/s; f2 = 13.7 ± 0.6 %) and a very fast (D3 = 404.00 ± 43.7 × 10(-3) mm(2)/s; f3 = 13.5 ± 0.8 %) diffusion compartment [results from the validation study]. The very fast compartment contributed to the IVIM signal only for b values ≤15 s/mm(2) CONCLUSION: The tri-exponential model provided the best fit for IVIM signal decay in the liver over the 0-800 s/mm(2) range. In IVIM analysis of normal liver, a third very fast (pseudo)diffusion component might be relevant. KEY POINTS: • For normal liver, tri-exponential IVIM model might be superior to bi-exponential • A very fast compartment (D = 404.00 ± 43.7 × 10 (-3) mm (2) /s; f = 13.5 ± 0.8 %) is determined from the tri-exponential model • The compartment contributes to the IVIM signal only for b ≤ 15 s/mm(2).

Software-based assessment of tumor margins after percutaneous thermal ablation of liver tumors: A systematic review.

PURPOSE: The purpose of this study was to make a systematic review of clinical studies evaluating software-based tumor margin assessment after percutaneous thermoablation (PTA) of liver tumors. MATERIALS AND METHODS: A systematic literature search was performed through Pubmed/MEDLINE, Embase and the Cochrane Library. Original studies published in English that reported on software-based assessment of ablation margins (AM) following PTA of liver tumors were selected. Studies were analyzed with respect to design, number of patients and tumors, tumor type, PTA technique, tumor size, target registration error, study outcome(s) (subtypes: feasibility, comparative, clinical impact, predictive or survival), and follow-up period. RESULTS: Twenty-nine articles (one multi-center and two prospective studies) were included. The majority were feasibility (26/29, 89.7%) or predictive (23/29, 79.3%) studies. AM was a risk factor of local tumor progression (LTP) in 25 studies (25/29, 86.2%). In nine studies (9/29, 31%) visual assessment overestimated AM compared with software-aided assessment. LTP occurred at the location of the thinnest margin in nine studies (9/29, 31%). Time for registration and analysis was heterogeneously reported, ranging between 5-30 min. Mean target registration error was reported in seven studies (7/29, 24.1%) at 1.62 mm (range: 1.20-2.23 mm). Inter-operator reproducibility was high (kappa range: 0.686-1). Ascites, liver deformation and inconspicuous tumor were major factors of co-registration error. CONCLUSION: Available studies present a low level of evidence overall, since most of them are feasibility, retrospective and single-center studies.

Assessment of water enema computed tomography: an effective imaging technique for the diagnosis of colon cancer: Colon cancer: computed tomography using a water enema.

AIM: The aim of this study was to assess the accuracy of water enema computed tomography (WECT) for the diagnosis of colon cancer. METHODS: A total of 191 patients referred for clinically suspected colon cancer were prospectively evaluated by WECT in a multicenter trial. Examination was contrast enhanced helical CT after colon filling through a rectal tube. For all the cases, final diagnosis was obtained by colonoscopy and/or surgery. CT data were interpreted both locally and at a centralized site by a specialized and general radiologist. RESULTS: Seventy-one patients were diagnosed with colon cancer. Overall, WECT sensitivity and specificity were 98.6 and 95.0%, respectively. Positive and negative predictive values were 92.1 and 99.1%, respectively. In a subgroup of 33 patients with unclean bowel, the sensitivity and specificity of WECT were 95.0 and 92.3%, respectively. The correlation between local radiologists and the specialized radiologist was excellent (Kappa = 0.87) as was the correlation between the general radiologist and the specialist (Kappa = 0.92). CONCLUSION: This prospective analysis demonstrates that WECT is an effective, safe, and simple imaging technique for the diagnosis of colon cancer and can be proposed when a strong clinical suspicion of colon cancer is present, especially in frail patients.

Liver venous deprivation versus portal vein embolization before major hepatectomy: future liver remnant volumetric and functional changes.

BACKGROUND: We previously showed that embolization of portal inflow and hepatic vein (HV) outflow (liver venous deprivation, LVD) promotes future liver remnant (FLR) volume (FLR-V) and function (FLR-F) gain. Here, we compared FLR-V and FLR-F changes after portal vein embolization (PVE) and LVD. METHODS: This study included all patients referred for liver preparation before major hepatectomy over 26 months. Exclusion criteria were: unavailable baseline/follow-up imaging, cirrhosis, Klatskin tumor, two-stage hepatectomy. 99mTc-mebrofenin SPECT-CT was performed at baseline and at day 7, 14 and 21 after PVE or LVD. FLR-V and FLR-F variations were compared using multivariate generalized linear mixed models (joint modelling) with/without missing data imputation. RESULTS: Baseline FLR-F was lower in the LVD (n=29) than PVE group (n=22) (P<0.001). Technical success was 100% in both groups without any major complication. Changes in FLR-V at day 14 and 21 (+14.2% vs. +50%, P=0.002; and +18.6% vs. +52.6%, P=0.001), and in FLR-F at day 7, 14 and 21 (+23.1% vs. +54.3%, P=0.02; +17.6% vs. +56.1%, P=0.006; and +29.8% vs. +63.9%, P<0.001) differed between PVE and LVD group. LVD (P=0.009), age (P=0.027) and baseline FLR-V (P=0.001) independently predicted FLR-V variations, whereas only LVD (P=0.01) predicted FLR-F changes. After missing data handling, LVD remained an independent predictor of FLR-V and FLR-F variations. CONCLUSIONS: LVD is safe and provides greater FLR-V and FLR-F increase than PVE. These results are now evaluated in the HYPERLIV-01 multicenter randomized trial.

Transarterial Chemoembolization of Hepatocellular Carcinoma with Idarubicin-Loaded Tandem Drug-Eluting Embolics.

: Objective: To describe the responses, toxicities and outcomes of HCC patients treated by transarterial chemoembolization (TACE) using idarubicin-loaded TANDEM beads. Materials and Methods: Seventy-two consecutive patients (mean age: 71 years (58-84 years)) with HCC were treated by TACE using idarubicin-loaded TANDEM in a first line, over a five-year period. Most patients (89%) had liver cirrhosis classified as Child-Pugh A (90%). BCLC B classification applied in 85% of cases. Baseline tumor burden was limited to one to three nodules in 92% of cases, unilobar in 88% cases, with a median tumor diameter of 55 mm (range: 13-150 mm). Toxicity was assessed using NCI CTC AE v4.0. Response was assessed using mRECIST criteria. Time-to-treatment failure (TTTF) and overall survival (OS) were also calculated based on Kaplan-Meier method. Result: Of 141 TACE sessions performed with bead sizes of 100 and 75 µm in 42 (29.8%) and 99 (70.2%) sessions, respectively. In 78% of all TACE sessions, the full dose of idarubicin-loaded beads was injected. Grade 3-4 AE were observed after 73 (52%) sessions, most of them being biological. Multi-organ failure was observed three days after the first TACE in a Child B patients, unfortunately leading to death. Overall, the best objective response rate (ORR) was 65%. Median follow-up lasted 14.3 months (95% CI: 11.2-18.8 months). Median TTTF and OS were 14.4 months (95% CI: 7.2-24.6 months) and 34.6 months (95% CI: 24.7-not reached) respectively. Conclusion: In this retrospective study involving well-selected HCC patients, high ORR and long TTTF and OS are observed after TACE using idarubicin-loaded TANDEM. A randomized trial is needed.

[Portal vein embolization: Present and future]. / Embolisation portale préopératoire : présent et futur.

Portal vein embolization consists of occluding a part of the portal venous system in order to achieve the hypertrophy of the non-embolized liver segments. This technique is used during the preoperative period of major liver resection when the future remnant liver (FRL) volume is insufficient, exposing to postoperative liver failure, main cause of death after major hepatectomy. Portal vein embolization indication depends on the FRL, commonly assessed by its volume. Nowadays, FRL function evaluation seems more relevant and can be measured by 99mTc labelled mebrofenin scintigraphy. Portal vein embolization procedure is mostly performed with percutaneous trans-hepatic access by using ultrasonography guidance and consists of embolic agent injection, such as cyanoacrylate, in the targeted portal vein branches with fluoroscopic guidance. It is a safe and well-tolerated technique, with extremely low morbi-mortality. Portal vein embolization leads to sufficient FRL hypertrophy in about 80% of patients, allowing them to undergo surgery from which they were initially rejected. The two main reasons of non-resection are tumor progression (≈15% of cases) and FRL insufficient hypertrophy (≈5% of cases). When portal vein embolization is not enough to obtain adequate FRL regeneration, hepatic vein embolization may potentiate its effect (liver venous deprivation technique).