Objectives: To evaluate the reliability of attenuation values of the liver parenchyma and focal liver lesions on virtual unenhanced images from arterial (VUEart) and portal venous phases (VUEport) compared to native unenhanced (NU) attenuation values in patients referred for assessment of malignant liver lesions. Methods: Seventy-three patients with confirmed primary or metastatic liver tumors who underwent a multiphase contrast-enhanced rapid-switching kVp dual-energy CT (rsDECT) were included in this IRB-approved retrospective study. Both qualitative and quantitative analyses - including the lesion-to-liver contrast-to-noise ratio (LL-CNR) - were performed and compared between NU and both VUEart and VUEport images. Results: The mean liver attenuation values were significantly lower in VUEart images (56.7 +/- 6.7 HU) than in NU images (59.6 +/- 7.5 HU, p = 0.008), and were comparable between VUEart and VUEport images (57.9 +/- 6 UH, p = 0.38) and between VUEport and NU images (p = 0.051). The mean liver lesions attenuation values were comparable between NU, VUEart and VUEport images (p = 0.60). Strong and significant correlations values were found both in liver lesions and tumor-free parenchyma (r = 0.82-0.91, p < 0.01). The mean LL-CNR was significantly higher in VUEart and VUEport images than in NU images (1.7 +/- 1 and 1.6 +/- 1.1 vs 0.9 +/- 0.6; p < 0.001), but was comparable between VUEart and VUEport images (p > 0.9). Lesion conspicuity was significantly higher in VUEport images than in NU images (p < 0.001). Conclusion: VUEport images derived from 3rd generation rsDECT could confidently replace NU images in patients undergoing assessment for malignant liver lesions. These images provide comparable attenuation values in both liver lesions and liver parenchyma while reducing the radiation dose and scanning time.

Background Post-surgical bleeding of the main portal vein (PV) is a rare event but difficult to manage surgically. Among the different options of treatment, endovascular stenting of the PV can be considered. We reported two cases of stent-graft placement in PV with subsequent closure of the portal vein access with two percutaneous closure devices deployed simultaneously. Cases presentation The first patient was a 43 years-old woman affected with a pseudoaneurysm of the extrahepatic PV, occurred after a duodenocephalopancreasectomy performed for a neuroendocrine tumour of the pancreatic isthmus. The second patient was a 54 years-old man suffering from multiple episodes of bleeding after liver transplantation, due to a PV fissure. In both cases, a stent graft was placed into the portal system, between the PV and the superior mesenteric vein through a right trans-hepatic access to the portal system. In both cases, a final control showed patency of the mesenteric vein and PV and no endoleak detection. At the end of the procedure, two percutaneous closure devices were loaded, to close the transhepatic portal access. In one case, one of the devices did not work and the entry point was managed with a single device, without further complications. No bleeding was seen though the entry point nor at the US examination performed right after the procedure. After procedure, patients were prescribed with low-molecular weight heparin (LMWH) and kept under surveillance. For both patients, CT scan performed within 24h after the procedure, showed a patent stent-graft and no evidence of any venous portal ischemia. The first patient was then transferred to another hospital, to continue observation and medical management. The second one underwent 2 months of hospitalization, during which he developed a pancreatic fistula and mild renal insufficiency. Then, he left the hospital to its native Country to continue his medical. Conclusion PV stent-graft placement seems a feasible option to manage portal bleeding. Trans-hepatic access is an easy and fast approach. The trans-hepatic portal accesses may be successfully managed with the deployment of percutaneous closure devices.

We set out to compare three types of three-dimensional CBCT-based imaging guidance modalities in a phantom study: image fusion with fluoroscopy (IF), electromagnetic navigation (EMN) and the association of both technologies (CEMNIF). Four targets with a median diameter of 11 mm [first quartile (Q1): 10; third quartile (Q3): 12] with acute angle access (z-axis < 45°) and four targets of 10 mm [8–15] with large angle access (z-axis > 45°) were defined on an abdominal phantom (CIRS, Meditest, Tabuteau, France). Acute angle access targets were punctured using IF, EMN or CEMNIF and large angle access targets with EMN by four operators with various experiences. Efficacy (target reached), accuracy (distance between needle tip and target center), procedure time, radiation exposure and reproducibility were explored and compared. All targets were reached (100% efficacy) by all operators. For targets with acute angle access, procedure times (EMN: 265 s [236–360], IF: 292 s [260–345], CEMNIF: 320 s [240–333]) and accuracy (EMN: 3 mm [2–5], IF: 2 mm [1–3], CEMNIF: 3 mm [2–4]) were similar. Radiation exposure (EMN: 0; IF: 708 mGy.cm2 [599–1128]; CEMNIF: 51 mGy.cm2 [15–150]; p < 0.001) was significantly higher with IF than with CEMNIF and EMN. For targets with large angle access, procedure times (EMN: 345 s [259–457], CEMNIF: 425 s [340–473]; p = 0.01) and radiation exposure (EMN: 0, CEMIF: 159 mGy.cm2 [39–316]; p < 0.001) were significantly lower with EMN but with lower accuracy (EMN: 4 mm [4–6] and CEMNIF: 4 mm [3, 4]; p = 0.01). The operator’s experience did not impact the tested parameters regardless of the technique. In this phantom study, EMN was not limited to acute angle targets. Efficacy and accuracy of puncture for acute angle access targets with EMN, IF or CEMNIF were similar. CEMNIF is more accurate for large angle access targets at the cost of a slightly higher procedure time and radiation exposure.

Colorectal cancer is the third most common cancer and the fourth most common cancer cause of death globally, accounting for roughly 1.2 million new cases and 600,000 deaths per year [1]. Incidence is low at ages younger than 50 years, but strongly increases with age. Median age at diagnosis is about 70 years in developed countries [2]. Colorectal cancer develops mostly without any symptoms in the early stages. In 15–30% of cases, however, CRC patients present with symptoms of acute abdomen such as bowel perforation, obstruction, or gastrointestinal bleeding [3]. Those complications mostly occur in elderly patients and are associated with poor prognosis [4]. These poor outcomes start at their initial hospital admission and also impacts long-term survival [3]. Elderly patients with CRC may be specifically at risk for emergent presentation because of medical comorbid conditions, insufficient screening, unrecognized symptoms, and inadequate overall access to the health-care system [4]. Imaging hence plays a key role in this setting. Its first objective is to provide the earliest diagnosis of any complication. Its second objective is increasingly dealing with interventional therapy of some complications associated with colorectal cancer treatment. This chapter will go through the role of imaging in the four major complications occurring in colorectal cancer setting, with a special focus on the pre-therapeutic imaging strategy in complicated or advanced CRC.

EBRT is underutilized in most Western countries for locoregional treatment of HCC. We aimed to assess the safety and outcome in patients with HCC treated by EBRT. Between January 2011 and November 2018, 83 patients with any stage of HCC were referred to our center for EBRT treatment. All toxicities have been evaluated according to the Common Terminology Criteria for Adverse Events, 4.0. Liver function was reported by Child-Pugh classification (CPC). Response to EBRT was evaluated using m-RECIST criteria. The efficacy endpoints were local control rate (LCR), progression-free survival (PFS) and overall survival (OS), calculated by Kaplan-Meier method. Stepwise regression analyses of predictive factors for toxicity and of prognostic factors for local control (LC) and OS were performed. Seventy-four patients with 83 hepatic lesions were analyzed. The median age was 70 years (range, 40-90). Sixty-eight (92%) patients were cirrhotic, most were compensated (81% had a Child Pugh score ≤ 7). Patients were staged according to Barcelona Clinical Liver Cancer (BCLC) classification as stage 0/A (39%), stage B (20%), stage C (38%), and stage D (3%). Median tumor size was 49 mm (range, 8-140). Stereotactic Body Radiation Therapy (SBRT) was used in 80% of patients delivering a median dose of 42 Gy with a median dose per fraction of 5 Gy. In terms of safety, the most common event was fatigue in 34 (44.6%) patients. All grades of toxicity were recorded in 44 (59.5%) patients, among whom 37 (84%) had grade 1 or 2 toxicities. Five (6.8%) patients had a worsening CPC of ≥ 2 points, all but one recovered to baseline CPC. CPC ≥ 7, tumor size ≥ 52 mm and D700cc ≥ 15 Gy were significant factors for a toxicity ≥ grade 2 in univariate analysis but only tumor size ≥ 52 mm remained an independent factor in multivariate analysis (tumor size ≥ 52 mm vs. < 52 mm, HR = 3, 95% CI 1.32-40.3, p=0.0227) The median follow-up duration was 22 months (range, 1-75). Sixty-four (86.5%) patients were available for evaluation and 21 (32.8%) patients had a completed response. The best objective response was observed in 47 (73.4%) patients, with an interval of 7.6 months since the end of EBRT. The LCR was 75.3% and 66.1% at 1 and 2 years, respectively. Alpha-fetoprotein (AFP) was independent factor for LC (AFP ≥ 969 vs. < 969, HR = 3.63, 95% CI 1.16-11.37, p=0.026). PFS and OS at 1 year and 2 years were 32.6%, 21% and 57%, 47.8%, respectively. Our study showed that EBRT using mainly SBRT technique could be safely delivered in cirrhotic patients with all stages of HCC. However, high caution should be paid for large tumors. Further prospective studies separately evaluating the role of SBRT in distinct stages of the disease are strongly encouraged.

AIM: To evaluate the clinical benefits on image quality (IQ) of adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) in multiphasic liver CT compared to filtered back-projection (FBP), in patients and on phantoms using a novel task-based metric. MATERIALS AND METHODS: Image data of 65 patients who underwent a routine multiphasic liver CT during a 1-month period were reconstructed with FBP, ASIR50, ASIR80, and MBIR. IQ was assessed qualitatively by ranking the most distal hepatic artery (HA) and portal vein (PV) visible; and quantitatively by measuring contrast-to-noise ratio (CNR) of the liver parenchyma, HA and PV. IQ was compared between each reconstruction and correlated to CNR and detectability index (d') measurements computed on phantoms scanned with the same CT protocol as for patients. RESULTS: HA and PV were seen more distally on MBIR and ASIR80 compared to FBP (p <= 0.001). The CNR correlated weakly between patient and phantom (r=0.76 and 0.80 for HA and PV, respectively), whereas d' correlated strongly with the division order of HA and PV (r=0.96 and 0.95, respectively). CONCLUSION: MBIR and ASIR significantly improve the IQ of multiphasic liver CT, especially through better distal detection of HA and PV, in agreement with the adapted task-based metric d' estimated on phantoms. (C) 2018 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

To compare the added values of hepatobiliary phase (HBP) MRI and contrast-enhanced ultrasound (CEUS) in addition to inconclusive extracellular gadolinium-based contrast-enhanced MRI (CE-MRI) to characterize benign hepatocellular tumors (BHT).

OBJECTIVES:To determine the degree of relationship between iodine concentrations derived from dual-energy CT (DECT) and perfusion CT parameters in patients with advanced HCC under treatment.METHODS:In this single-centre IRB approved study, 16 patients with advanced HCC treated with sorafenib or radioembolization who underwent concurrent dynamic perfusion CT and multiphase DECT using a single source, fast kV switching DECT scanner were included. Written informed consent was obtained for all patients. HCC late-arterial and portal iodine concentrations, blood flow (BF)-related and blood volume (BV)-related perfusion parameters maps were calculated. Mixed-effects models of the relationship between iodine concentrations and perfusion parameters were computed. An adjusted p value (Bonferroni method) < 0.05 was considered significant.RESULTS:Mean HCC late-arterial and portal iodine concentrations were 22.7±12.7 mg/mL and 18.7±8.3 mg/mL, respectively. Late-arterial iodine concentration was significantly related to BV (mixed-effects model F statistic (F)=28.52, p<0.0001), arterial BF (aBF, F=17.62, p<0.0001), hepatic perfusion index (F=28.24, p<0.0001), positive enhancement integral (PEI, F=66.75, p<0.0001) and mean slope of increase (F=32.96, p<0.0001), while portal-venous iodine concentration was mainly related to BV (F=29.68, p<0.0001) and PEI (F=66.75, p<0.0001).CONCLUSIONS:In advanced HCC lesions, DECT-derived late-arterial iodine concentration is strongly related to both aBF and BV, while portal iodine concentration mainly reflects BV, offering DECT the ability to evaluate both morphological and perfusion changes.KEY POINTS:• Late-arterial iodine concentration is highly related to arterial BF and BV. • Portal iodine concentration mainly reflects tumour blood volume. • Dual-energy CT offers significantly decreased radiation dose compared with perfusion CT.

Introduction: To evaluate the performances of dual-tracer 18-F Fluorocholine (FCH) and Fluorodeoxyglucose (FDG) PET/CT imaging to diagnose portal vein tumor thrombosis. Methods: Eighty-five consecutive patients with hepatocellular carcinoma and referred for staging with dual-tracer PET/CT were included. PET/CT was analyzed by a nuclearist being unaware of the results of other imaging techniques. A tumoral thrombus was defined on PET/CT as a linear area of abnormal uptake in correspondence of a vessel, either an increased or decreased uptake on FCH scan, or an increased uptake on FDG scan. Considered as the standard of reference the CT or MRI (performed less than one month around PET/CT) were analyzed separately by a single radiologist. The presence of tumoral thrombus was determined on usual diagnostic criteria. The tumoral origin of the thrombus when doubtful was assessed on the follow up, by contrast enhanced ultrasonography or pathological analysis. Results: Eighteen cases if portal vein tumor thrombosis were found. FDG PET/CT was positive or doubtful in 17 cases, while dual-tracer PET/CT increased the diagnostic confidence by excluding one false positive and identifying one additional true positive. Overall, the sensitivity, specificity and accuracy were respectively 94.4%, 98.5% and 97.6% for FDG PET/CT, and 100%, 100% and 100% for dual-tracer PET/CT. Conclusion: In patients with HCC, dual-tracer PET/CT enables an accurate diagnosis of portal vein tumor thrombosis, which has an essential prognostic value. The joint reading of morphological images and metabolic images provides good confidence for portal tumor thrombosis diagnosis.

To evaluate both in vivo and in phantom studies, dose reduction, and image quality of body CT reconstructed with model-based iterative reconstruction (MBIR), performed during patient follow-ups for lymphoma.