Proposal of early CT morphological criteria for response of liver metastases to systemic treatments in gastroenteropancreatic neuroendocrine tumors: Alternatives to RECIST.

RECIST 1.1 criteria are commonly used with computed tomography (CT) to evaluate the efficacy of systemic treatments in patients with neuroendocrine tumors (NETs) and liver metastases (LMs), but their relevance is questioned in this setting. We aimed to explore alternative criteria using different numbers of measured LMs and thresholds of size and density variation. We retrospectively studied patients with advanced pancreatic or small intestine NETs with LMs, treated with systemic treatment in the first-and/or second-line, without early progression, in 14 European expert centers. We compared time to treatment failure (TTF) between responders and non-responders according to various criteria defined by 0%, 10%, 20% or 30% decrease in the sum of LM size, and/or by 10%, 15% or 20% decrease in LM density, measured on two, three or five LMs, on baseline (≤1 month before treatment initiation) and first revaluation (≤6 months) contrast-enhanced CT scans. Multivariable Cox proportional hazard models were performed to adjust the association between response criteria and TTF on prognostic factors. We included 129 systemic treatments (long-acting somatostatin analogs 41.9%, chemotherapy 26.4%, targeted therapies 31.8%), administered as first-line (53.5%) or second-line therapies (46.5%) in 91 patients. A decrease ≥10% in the size of three LMs was the response criterion that best predicted prolonged TTF, with significance at multivariable analysis (HR 1.90; 95% CI: 1.06-3.40; p = .03). Conversely, response defined by RECIST 1.1 did not predict prolonged TTF (p = .91), and neither did criteria based on changes in LM density. A ≥10% decrease in size of three LMs could be a more clinically relevant criterion than the current 30% threshold utilized by RECIST 1.1 for the evaluation of treatment efficacy in patients with advanced NETs. Its implementation in clinical trials is mandatory for prospective validation. Criteria based on changes in LM density were not predictive of treatment efficacy. CLINICAL TRIAL REGISTRATION: Registered at CNIL-CERB, Assistance publique hopitaux de Paris as "E-NETNET-L-E-CT" July 2018. No number was assigned. Approved by the Medical Ethics Review Board of University Medical Center Groningen.

Whole Body MRI in the Detection of Lymph Node Metastases in Patients with Testicular Germ Cell Cancer.

Whole-Body Magnetic Resonance Imaging (WB-MRI) is increasingly used for metastatic screening in oncology. This prospective single center study assesses the diagnostic value of WB-MRI including diffusion weighted imaging (DWI) and identifies the sufficient protocol for metastatic lymph node detection in patients with testicular germ cell cancer (TGCC). Forty-three patients underwent contrast enhanced thoraco-abdominopelvic CT (TAP-CT) and WB-MRI with DWI for metastatic lymph node screening. Two independent readers reviewed CTs and WB-MRIs. The diagnostic performance of different imaging protocols (CT, complete WB-MRI, T1W + DWI, T2W + DWI), the agreement between these protocols and the reference standard, the reproducibility of findings and the image quality (Signal and contrast to Noise Ratios, Likert scale) were studied. Reproducibility was very good regardless of both lesion locations (retroperitoneal vs distant lymph nodes, other lesions) and the reader. Diagnostic accuracy of MRI was ≥95% (regardless of the locations and imaging protocol); accuracy of CT was ≥93%. There was a strict overlap of 95% CIs associated with this accuracy between complete WB-MRI, T1W + DWI and T2W + DWI, regardless of the reader. Higher Likert score and SNR were observed for DWI, followed by T2W and T1W sequences. In conclusion, a fast WB-MRI protocol including T2W and DWI is a sufficient, accurate, non-irradiating alternative to TAP-CT for metastatic lymph node screening in TGCC.

Prediction of tumor response and patient outcome after radioembolization of hepatocellular carcinoma using 90Y-PET-computed tomography dosimetry.

AIM: 90Y-radioembolization using glass or resin microspheres is increasingly used for the treatment of hepatocellular carcinoma (HCC). The aim of this retrospective study is to determine the prognostic relevance of dosimetric parameters defined with 90Y-PET-CT obtained immediately after radioembolization. METHODS: Forty-five HCC patients, mostly with multiple lesions, were treated by radioembolization between 2011 and 2017. After treatment, all underwent a 90Y PET-CT with time of flight reconstruction (90Y-TOF-PET-CT). Tumor absorbed dose and cumulative tumor dose-volume histogram were calculated using a dose point Kernel convolution algorithm. The radiological tumor response was assessed using modified (m)-RECIST criteria. Progression-free-survival (PFS) and overall survival (OS) were analyzed using the Kaplan-Meier method and Cox regression analysis. RESULTS: Twenty-six patients were treated with glass microspheres (73 lesions) and nineteen with resin microspheres (60 lesions). Thresholds of 118 and 61 Gy for glass and resin microspheres respectively correlate well with radiological response with a positive predictive value (PPV) of 98 and 80% and discriminate patient outcome with regard to PFS (P = 0.03 and 0.005) and OS (P = 0.003 and 0.007). Using dose volume histogram, a minimal absorbed dose of 40 Gy in 66% of the tumor volume (defined as D66) was highly predictive of radiological response (PPV = 94%), PFS (P < 0.001) and OS (P = 0. 008), for either device. CONCLUSION: Dosimetric parameters obtained using 90Y-PET-CT are predictive of tumor response, PFS and OS. In clinical practice, a systematic dosimetric evaluation using 90Y PET should be implemented to help predicting patient outcomes.

Prospective comparison of a fast 1.5-T biparametric with the 3.0-T multiparametric ESUR magnetic resonance imaging protocol as a triage test for men at risk of prostate cancer.

OBJECTIVE: To compare prospectively the diagnostic performance of a biparametric (T2-weighted imaging [T2WI] and diffusion-weighted imaging [DWI]) 1.5-T fast magnetic resonance imaging (fMRI) protocol with the standard 3.0-T multiparametric MRI (mpMRI) protocol of the European Society of Urological Imaging (ESUR) in men referred for a prostate biopsy. PATIENTS AND METHODS: Ninety patients with a prostate cancer (PCa) risk of ≥10% according to the SWOP calculator 4 underwent first fMRI and then the reference mpMRI. Patients with Prostate Imaging Reporting and Data System (PI-RADS) v.2 lesions ≥3/5 on the mpMRI were scheduled for MRI/ultrasonography (US) fusion-guided prostate biopsy. Performance of fMRI was assessed using receiver-operating characteristic curve analysis and mpMRI as reference. Calculation of inter-technique agreement on PI-RADS v.2 score by Cohen's κ. RESULTS: The diagnostic accuracy of fMRI shown by the lesion-based analysis was excellent: area under the curve (AUC) 0.961 (P < 0.001), sensitivity 95%, specificity 97%, positive predictive value (PPV) 99%, negative predictive value (NPV) 89%. The patient-based analysis showed an AUC for fMRI of 0.975 (P < 0.001), a sensitivity of 98%, a specificity of 97%, a PPV of 98% and an NPV of 97%. Agreement on the PI-RADS score between both protocols was found to be good (κ = 0.78 [0.57; 0.99]); fMRI missing PI-RADS 4 lesions in three patients. Biopsy results showed no cancer in two patients (two cores per nodule) and Gleason 6 cancer in one patient. There was only one false-positive fMRI, with a PI-RADS score of 4, whose biopsy was negative. CONCLUSION: In the triage of men with a high risk of PCa for prostate biopsy, an f MRI protocol (1.5-T magnet, T2WI + DWI, <15 min) may safely replace the traditional ESUR 3.0-T mpMRI protocol, saving time and contrast injection.

Impact of Intraoperative Pancreatoscopy with Intraductal Biopsies on Surgical Management of Intraductal Papillary Mucinous Neoplasm of the Pancreas.

BACKGROUND: Because of its known malignant potential, precise histologic diagnosis of intraductal papillary mucinous neoplasm of the pancreas (IPMN) during intraoperative pancreatoscopy (IOP) is essential for complete surgical resection. The impact of IOP on perioperative IPMN patient management was reviewed over 20 years of practice at Cliniques universitaires Saint-Luc, Brussels, Belgium. STUDY DESIGN: Among 86 IPMN patients treated by pancreatectomy between 1991 and 2013, 21 patients had a dilated main pancreatic duct enabling IOP and were retrospectively reviewed. The IOP was performed using an ultrathin flexible endoscope and biopsy forceps, and specimens of all suspicious lesions underwent frozen section examination. RESULTS: Complete IOP with intraductal biopsies was easily and safely performed in 21 patients, revealing 8 occult IPMN lesions. In 5 cases (23.8%), initially planned surgical resection was modified secondary to IOP: 3 for carcinoma in situ and 2 for invasive carcinoma. The postoperative morbidity rate at 3 months was 25.0% (5 of 20); 1 patient died from septic shock postoperatively and was excluded. Median follow-up was 93 months (range 13 to 248 months). Nineteen of 21 patients were still alive and free of disease at last follow-up (90.5%); there was 1 patient with invasive carcinoma at initial pathology (pT3 N1) who died of pulmonary recurrence 21 months after surgery. CONCLUSIONS: Intraoperative pancreatoscopy of the main pancreatic duct combined with intraductal biopsies plays a significant role in the surgical management of IPMN patients and should be used in all patients presenting a sufficiently dilated main pancreatic duct.

Living Donor Liver Transplantation in Children: Surgical and Immunological Results in 250 Recipients at Université Catholique de Louvain.

OBJECTIVES: To evaluate the outcome of pediatric living donor liver transplantation (LDLT) regarding portal vein (PV) reconstruction, ABO compatibility, and impact of maternal donation on graft acceptance. BACKGROUND: LDLT and ABO-mismatched transplantation constitute feasible options to alleviate organ shortage in children. Vascular complications of portal hypoplasia in biliary atresia (BA) and acute rejection (AR) are still major concerns in this field. METHODS: Data from 250 pediatric LDLT recipients, performed at Cliniques Universitaires Saint-Luc between July 1993 and June 2012, were collected retrospectively. Results were analyzed according to ABO matching and PV complications. Uni- and multivariate analyses were performed to study the impact of immunosuppression, sex matching, and maternal donation on AR rate. RESULTS: Overall, the 10-year patient survival rate was 93.2%. Neither patient or graft loss nor vascular rejection, nor hemolysis, was encountered in the ABO nonidentical patients (n = 58), provided pretransplant levels of relevant isoagglutinins were below 1/16. In BA recipients, the rate of PV complications was lower after portoplasty (4.6%) than after truncal PV anastomosis (9.8%) and to jump graft interposition (26.9%; P = 0.027). In parental donation, maternal grafts were associated with higher 1-year AR-free survival (55.2%) than paternal grafts (39.8%; P = 0.041), but only in BA patients. CONCLUSIONS: LDLT, including ABO-mismatched transplantation, constitutes a safe and efficient therapy for liver failure in children. In BA patients with PV hypoplasia, portoplasty seems to constitute the best technique for PV reconstruction. Maternal donation might be a protective factor for AR.

Hepatocellular adenoma management: call for shared guidelines and multidisciplinary approach.

Hepatocellular adenomas are rare benign nodules developed mainly in women taking oral contraceptives. They are solitary or multiple. Their size is highly variable. There is no consensus in the literature for their management except that once their size exceeds 5 cm nodules are taken out to prevent 2 major complications: bleeding and malignant transformation. There are exceptions particularly in men where it is recommended to remove smaller nodules. Since the beginning of this century, major scientific contributions have unveiled the heterogeneity of the disease. HCA are composed of four major subtypes. HNF1A (coding for hepatocyte nuclear factor 1a) inactivating mutations (H-HCA); inflammatory adenomas (IHCA); the ß-catenin-mutated HCAs (ß-HCA) and unclassified HCA (UHCA) occurring in 30-40%, 40-50%, 10-15% and 10% of all HCA, respectively. Half of ß-HCAs are also inflammatory (ß-IHCA). Importantly, ß-catenin mutations are associated with a high risk of malignant transformation. HCA subtypes can be identified on liver tissue, including biopsies using specific immunomarkers with a good correspondence with molecular data. Recent data has shown that TERT promoter mutation was a late event in the malignant transformation of ß-HCA, ß-IHCA. Furthermore, in addition to ß-catenin exon 3 mutations, other mutations do exist (exon 7 and 8) with a lower risk of malignant transformation. With these new scientific informations, we have the tools to better know the natural history of the different subtypes, in terms of growth, disappearance, bleeding, malignant transformation and to investigate HCA in diseased livers (vascular diseases, alcoholic cirrhosis). A better knowledge of HCA should lead to a more rational management of HCA. This can be done only if the different subspecialties, including hepatologists, liver pathologists, radiologists and surgeons work altogether in close relationship with molecular biologists. It is a long way to go.

One-step TNM staging of high-risk prostate cancer using magnetic resonance imaging (MRI): toward an upfront simplified "all-in-one" imaging approach?

BACKGROUND: Multiparametric magnetic resonance imaging (mpMRI) is the standard for local prostate cancer (PCa) staging. Whole-body MRI (wbMRI) has shown capabilities for metastatic screening. This study assesses the feasibility and value of an all-in-one AJCC TNM staging of PCa during a unique MRI session combining mpMRI and wbMRI. METHODS: Thirty consecutive patients with "high-risk" PCa prospectively underwent mpMRI of the prostate and wbMRI, in addition to (99m) Tc bone scan (BS), completed with standard X-rays (±TXR) and contrast enhanced CT for distant staging. For the statistical analysis, a "best valuable comparator" (BVC) combining a panel review of all available baseline and follow-up imaging, biological, and clinical data was used to adjudicate lymph node and bone metastatic status. RESULTS: Prostate mpMRI was analyzed using ESUR guidelines. Sensitivity of BS ± TXR combined with CT and of wbMRI for detecting metastases (bones or nodes) was 85% and 100%, respectively, and specificity was 88% and 100%, respectively. For the overall staging of the patients as being either N0M0 or having disease extension beyond the prostate, wbMRI was superior to the combination of BS and CT (improvement in all ROC characteristics and of AUC by 13.6% (95% CI: +0.7% to +26.5%, P = 0.039)). The main limitation is the limited number of patients. CONCLUSIONS: AJCC M and N staging using wbMRI is feasible during the same imaging session as mpMRI performed for T staging, in less then one hour. wbMRI outperforms BS ± TXR and abdomino-pelvic CT work up for discriminating subsets of patients with or without distant spread of the cancer.

Diagnosis of cyst infection in patients with autosomal dominant polycystic kidney disease: attributes and limitations of the current modalities.

Cyst infection is a diagnostic challenge in patients with autosomal dominant polycystic kidney disease (ADPKD) because of the lack of specific manifestations and limitations of conventional imaging procedures. Still, recent clinical observations and series have highlighted common criteria for this condition. Cyst infection is diagnosed if confirmed by cyst fluid analysis showing bacteria and neutrophils, and as a probable diagnosis if all four of the following criteria are concomitantly met: temperature of >38°C for >3 days, loin or liver tenderness, C-reactive protein plasma level of >5 mg/dL and no evidence for intracystic bleeding on computed tomography (CT). In addition, the elevation of serum carbohydrate antigen 19-9 (CA19-9) has been proposed as a biomarker for hepatic cyst infection. Positron-emission tomography after intravenous injection of 18-fluorodeoxyglucose, combined with CT, proved superior to radiological imaging techniques for the identification and localization of kidney and liver pyocyst. This review summarizes the attributes and limitations of these recent clinical, biological and imaging advances in the diagnosis of cyst infection in patients with ADPKD.

Celiac artery occlusive disease: a rare but potentially critical condition in patients undergoing pancreaticoduodenectomy.

BACKGROUND/AIMS: Undiagnosed occlusive disease of celiac trunk and/or superior mesenteric artery may lead to life-threatening complications after pancreatoduodenectomy. METHODOLOGY: Retrospective analysis of a consecutive series of 171 patients scheduled for pancreatico- duodenectomy or total pancreatectomy. RESULTS: The prevalence of arterial occlusive disease was 5.9% (10 patients), including complete celiac artery occlusive disease in 2 patients (1.2%). Preoperative diagnosis was achieved in 90% of the patients by lateral-views of imaging studies. In arterial stenosis <50% (3 patients), abstention was always successful. In arterial stenosis >50%, successful treatment options included abstention (n=1), preoperative endovascular dilatation (n=1) or stenting (n=1), division of the median arcuate ligament with (n=1) or without (n=1) postoperative endovascular stenting, and aorto-hepatic bypass (2 patients). No early postoperative ischemic complications occurred. However, one patient died from late intestinal ischemia. CONCLUSIONS: Arterial occlusive disease is rare in patients undergoing pancreatico-duodenectomy but expose the patient to severe complications if undiagnosed. A tailored management according to the type of arterial stenosis, to patients' indication for surgery and to patients' arterial anatomy is indicated. Surgical and endovascular management may be successfully combined.

Conservative and operative management of benign solid hepatic tumours: a successful stratified algorithm.

BACKGROUND: The progress of modern imaging studies has improved the diagnostic approach of benign liver tumours, leading to a tailored approach with increased conservative management. METHODS: One hundred and thirty-two patients suffering from benign hepatic tumours were enrolled in this study, including an operative (group I, 49 patients) and a conservative (group II, 83 patients) management. Patients' tumour and treatment features were analyzed. RESULTS: The mean patients' age was 39 years. Indication for resection based on diagnosis of tumour nature (hepatic cell adenoma or uncertain diagnosis) and significant tumour-related abdominal pain was 15% out of 33 patients with hepatic haemangioma, 21.7% out of 60 patients with focal nodular hyperplasia and 78.4% out of 37 patients with hepatocellular adenoma. Mortality was nihil in group I. Complications and transfusion rates were related to the performance of major hepatectomy, when required for huge tumours. With a 95.5% of complete patients' follow-up during a mean of 92 months in group I and 87 months in group II, no misdiagnosis or evolution towards malignancy was encountered. Interestingly, 87.9% of all observed benign liver tumours remained stable, decreased in size or disappeared. None of the remaining lesions required surgery. CONCLUSION: A restrictive policy of surgical management of benign liver tumours based on clinical symptoms, tumour size and nature on imaging studies (including dubious lesions) and tumour biopsies in selected cases is safe and reliable with a low-operative mortality in resected patients and satisfactory disease-control in the vast majority of observed benign liver tumours.

Transvascular and interstitial transport in rat hepatocellular carcinomas: dynamic contrast-enhanced MRI assessment with low- and high-molecular weight agents.

PURPOSE: To assess which MRI-derived kinetic parameters reflect decreased transvascular and interstitial transport when low- and high-molecular-weight agents are used in rat hepatocellular carcinomas. MATERIALS AND METHODS: Dynamic MRI after injection of a low-molecular-weight contrast agent of 0.56 kDa (Gd-DOTA, gadoterate) and two high-molecular-weight contrast agents of 6.47 kDa (P792, gadomelitol) and 52 kDa (P717, carboxymethyldextran Gd-DOTA) was performed in rats with chemically induced hepatocellular carcinomas. The data were analyzed with the Kety compartmental model, the extended Kety compartmental model in which it is assumed that the tissue voxels contain a vascular component, and the St Lawrence and Lee distributed-parameter model. RESULTS: The extravascular extracellular space accessible to the contrast agent v(e) and the extraction fraction E decreased with increasing molecular weight of the contrast agent. In contrast, the volume transfer constant Ktrans did not differ significantly when low- or high-molecular-weight agents were used. CONCLUSION: In this animal model the results suggest that the accessible extravascular extracellular space and the extraction fraction are more sensitive indicators of decreased transvascular and interstitial transport with high-molecular-weight agents than the volume transfer constant, which is a lumped representation of blood flow and permeability.

Magnetic resonance elastography for the noninvasive staging of liver fibrosis.

BACKGROUND & AIMS: The purpose of our study was to prospectively compare the success rate and diagnostic accuracy of magnetic resonance elastography, ultrasound elastography, and aspartate aminotransferase to platelets ratio index (APRI) measurements for the noninvasive staging of fibrosis in patients with chronic liver disease. METHODS: We performed a prospective blind comparison of magnetic resonance elastography, ultrasound elastography, and APRI in a consecutive series of patients who underwent liver biopsy for chronic liver disease in a university-based hospital. Histopathologic staging of liver fibrosis according to the METAVIR scoring system served as the reference. RESULTS: A total of 141 patients were assessed. The technical success rate of magnetic resonance elastography was higher than that of ultrasound elastography (133/141 [94%] vs 118/141 [84%]; P = .016). Magnetic and ultrasound elastography, APRI measurements, and histopathologic analysis of liver biopsy specimens were technically successful in 96 patients. The areas under the receiver operating characteristic curves of magnetic resonance elasticity (0.994 for F >or= 2; 0.985 for F >or= 3; 0.998 for F = 4) were larger (P < .05) than those of ultrasound elasticity, APRI, and the combination of ultrasound elasticity and APRI (0.837, 0.709, and 0.849 for F >or= 2; 0.906, 0.816, and 0.936 for F >or= 3; 0.930, 0.820, and 0.944 for F = 4, respectively). CONCLUSIONS: Magnetic resonance elastography has a higher technical success rate than ultrasound elastography and a better diagnostic accuracy than ultrasound elastography and APRI for staging liver fibrosis.

Prognostic risk factors of survival after resection of hepatocellular carcinoma.

BACKGROUND/AIMS: Surgical resection is a standard treatment of hepatocellular carcinoma, but liver cirrhosis is known to be associated to a high tumor recurrence rate. METHODOLOGY: A retrospective study of 55 consecutive patients (37 males, 18 females) suffering from hepatocellular carcinoma having undergone surgical resection. Hepatocellular carcinoma developed in 29 patients with normal liver (group A) and in 26 patients with chronic liver disease (CLD) (group B). Patients were significantly older and at high-risk in Group B. RESULTS: Radical liver resection was achieved in 98% (100% in group A; 96% in group B). Overall 2-month mortality was 2% (0% in group A; 4% in group B). The 5-year overall and disease-free survival was respectively 55% and 35%. However, the 5-year overall and disease-free survival was significantly better in Group A (71% and 59%) compared to Group B (37% and 6%) (p < 0.001), respectively. Multivariate statistical analysis demonstrated that age > 50 years, poor tumor differentiation and presence of satellite nodules were significant independent adverse predictive factors of overall and disease-free survival. CONCLUSIONS: Resection of HCC is safe and effective with satisfactory overall and disease-free survival rates, except when underlying chronic liver disease and poor tumor differentiation are present.

Liver fibrosis: noninvasive assessment with MR elastography versus aspartate aminotransferase-to-platelet ratio index.

PURPOSE: To prospectively compare the sensitivity and specificity of magnetic resonance (MR) elastography with those of the routinely available aspartate aminotransferase-to-platelet ratio index (APRI) test for staging hepatic fibrosis in patients who have undergone liver biopsy for suspicion of chronic liver disease, with histopathologic examination as the reference standard. MATERIALS AND METHODS: The study was approved by the ethics committee. All patients gave written informed consent. Eighty-eight patients (37 men, 51 women; mean age, 54.0 years +/- 13.1 [standard deviation]) who underwent liver biopsy for suspicion of chronic liver disease underwent MR elastography and APRI testing within 2 days after liver biopsy. At histopathologic examination, the fibrosis stage was assessed according to METAVIR scores (fibrosis scores F0 [no fibrosis] to F4 [cirrhosis]). MR elastography was performed by transmitting mechanical waves within the liver and measuring the small cyclic displacement of the liver spins with a phase-contrast spin-echo sequence. The performances of MR elastography and APRI testing were assessed, and the optimal cutoff values for fibrosis stage were determined with receiver operating characteristic (ROC) curve analysis. RESULTS: At MR elastography, areas under the ROC curves (A(z)) for elasticity and viscosity, respectively, were 0.999 and 0.863 at fibrosis scores greater than or equal to F2, 0.997 and 0.962 at scores greater than or equal to F3, and 1.000 and 0.986 at score F4. A(z) values for elasticity at MR were significantly larger than those for the APRI (0.854 at scores > or = F2, P < .001; 0.886 at scores > or = F3, P = .003; and 0.851 at score F4, P = .004). Optimal cutoff values of elasticity were 2.5 kPa for fibrosis scores greater than or equal to F2, 3.1 kPa for scores greater than or equal to F3, and 4.3 kPa for score F4. CONCLUSION: Large A(z) values for elasticity (>0.990 for scores > or = F2, > or = F3, and F4) show that MR elastography was accurate in liver fibrosis staging and superior to biochemical testing with APRIs.

Benign biliary inflammatory pseudotumor mimicking a Klatskin tumor.

Most biliary tumors at the liver hilum are malignant and, when possible, require radical surgical resection. However, few rare benign lesions exist, for which the differential diagnosis with malignancy is important in order to avoid aggressive surgical treatment. This is a retrospective case report. We report on two patients suffering from presumed inflammatory pseudotumor of the main biliary convergence, mimicking a Klatskin's tumor. Complete multidisciplinary work-up in a specialized hepatobiliary centre, including tumor markers, imaging studies and FDG-PET were strongly in favor of malignancy. The benign nature of the lesions was only suspected on the natural radiological evolution during the time waiting for surgical resection, with progressive spontaneous disappearance of tumor masses. Therefore, we were able to avoid extensive hepatobiliary surgery in both patients, including performance of an extended right hepatectomy. However, the patients had portal vein embolization as a first step in treating the disease, hopefully with no long-term consequences on patient status and liver function tests. Clinicians should be aware that tumors arising at the hepatic bifurcation are not always malignant, even if it is the most frequent cause. Despite extensive multidisciplinary work-up, there are still persisting difficulties in this differential diagnosis.

Liver fibrosis: non-invasive assessment with MR elastography.

The aim of this study was to assess the feasibility of using non-invasive MR elastography for determining the stage of liver fibrosis. Twenty-five consecutive patients who had liver biopsy for suspicion of chronic liver disease were included in the study. The stage of fibrosis on the biopsies was assessed according to the METAVIR scoring system from F0, no fibrosis, to F4, cirrhosis. MR elastography was performed by transmitting low-frequency (65 Hz) mechanical waves into the liver with a transducer placed at the back of the patients. The MR pulse sequence was a motion-sensitized spin-echo sequence, phase-locked to the mechanical excitation. The phase maps were processed to obtain shear elasticity and shear viscosity maps. The mean hepatic shear elasticity increased with increasing stage of fibrosis. The mean elasticity was 2.24 +/- 0.23 kPa in the 11 patients without substantial fibrosis (F0-F1 grades), 2.56 +/- 0.24 kPa in the four patients with substantial fibrosis (F2-F3) and 4.68 +/- 1.61 kPa in the 10 patients with cirrhosis (F4). The differences between groups were statistically significant (p