Contrast-enhanced CT and liver surface nodularity for the diagnosis of porto-sinusoidal vascular disorder: A case-control study.

BACKGROUND AND AIMS: Porto-sinusoidal vascular disorder (PSVD) is a rare and commonly overlooked cause of portal hypertension. The interest of CT analysis, including quantification of liver surface nodularity (LSN) for PSVD diagnosis has not been established. This study aimed at assessing the performance of LSN and CT features for a PSVD diagnosis in patients with signs of portal hypertension. APPROACH AND RESULTS: This retrospective case-control study included a learning cohort consisting of 50 patients with histologically proven PSVD, according to VALDIG criteria, and 100 control patients with histologically proven cirrhosis, matched on ascites. All patients and controls had at least one sign of portal hypertension and CT available within 1 year of liver biopsy. Principal component analysis of CT features separated patients with PSVD from patients with cirrhosis. Patients with PSVD had lower median LSN than those with cirrhosis (2.4 vs. 3.1, p < 0.001). Multivariate analysis identified LSN < 2.5 and normal-sized or enlarged segment IV as independently associated with PSVD. Combination of these two features had a specificity of 90% for PSVD and a diagnostic accuracy of 84%. Even better results were obtained in an independent multicenter validation cohort including 53 patients with PSVD and 106 control patients with cirrhosis (specificity 94%, diagnostic accuracy 87%). CONCLUSIONS: This study that included a total of 103 patients with PSVD and 206 patients with cirrhosis demonstrates that LSN < 2.5 combined with normal-sized or enlarged segment IV strongly suggests PSVD in patients with signs of portal hypertension.

Hepatobiliary MR contrast agents are useful to diagnose hepatocellular carcinoma in patients with Budd-Chiari syndrome.

BACKGROUND & AIMS: Hepatobiliary phase (HBP) images can discriminate between benign and malignant liver lesions, but it is unclear if this approach can be used in patients with Budd-Chiari syndrome (BCS). Thus, we aimed to assess the diagnostic utility of HBP images in patients with BCS. METHODS: This retrospective study included all patients admitted to our institution with a diagnosis of BCS and focal liver lesions on hepatobiliary contrast agent-enhanced MR imaging (HBCA-MRI) from 2000 to 2019. MR images were reviewed by 2 radiologists blinded to the diagnosis of the lesions. Patient and lesion characteristics were recorded, focusing on HBP imaging features. RESULTS: Twenty-six patients (mean 35 ± 11 years old [13-65]; 21 women [81%] 35 ± 12 years old [13-65]; 5 men [19%] 36 ± 10 years old [19-44]) with 99 benign liver lesions and 12 hepatocellular carcinomas (HCCs) were analyzed. Patients with HCC were significantly older than those with benign lesions (mean 50 ± 10 vs. 33 ± 9 years old, p = 0.003), with higher alpha-fetoprotein (AFP) levels (3/4 [75%] vs. 1/22 [5%] with AFP >15 ng/ml, p <0.001). Homogeneous hypointense signals were identified on HBP in 14 lesions, including 12/12 (100%) HCCs, and 2/99 (2%) benign lesions (p <0.001). Most benign liver lesions showed either peripheral (n = 52/99 [53%]) or homogeneous hyperintensity (n = 23/99 [23%]) on HBP. Lesions with signal hypointensity on HBP in patients with AFP serum levels >15 ng/ml were all HCCs. CONCLUSION: Most benign lesions showed homogeneous or peripheral hyperintensity on HBP images while all HCCs were homogeneously hypointense. HBP images are helpful to differentiate between benign lesions and HCCs and outperform other sequences. They should be systematically acquired for the characterization of focal lesions in patients with BCS. LAY SUMMARY: Hepatobiliary phase imaging is an approach that has recently been shown to discriminate between benign and malignant lesions in the liver. However, it was not known whether this imaging approach could be used effectively in patients with Budd-Chiari syndrome. Herein, we have shown that hepatobiliary phase imaging appears to be useful for differentiating between benign and malignant liver lesions in patients with Budd-Chiari syndrome.

Comparison of extracellular and hepatobiliary MR contrast agents for the diagnosis of small HCCs.

BACKGROUND & AIMS: The aim of this study was to use a head-to-head nodule comparison to compare the performance of extracellular contrast agent MRI (ECA-MRI) with that of hepatobiliary contrast agent MRI (HBA-MRI) for the non-invasive diagnosis of small hepatocellular carcinomas (HCCs). METHODS: Between August 2014 and October 2017, 171 patients with cirrhosis, each with 1 to 3 nodules measuring 1-3 cm, were enrolled across 8 centers. All patients underwent both an ECA-MRI and an HBA-MRI within a month. A non-invasive diagnosis of HCC was made when a nodule exhibited arterial phase hyper-enhancement (APHE) with washout at the portal venous phase (PVP) and/or delayed phase (DP) for ECA-MRI, or the PVP and/or HB phase (HBP) for HBA-MRI. The gold standard was defined by using a previously published composite algorithm. RESULTS: A total of 225 nodules, of which 153 were HCCs and 72 were not, were included. The sensitivites of both MRI techniques were similar. Specificity was 83.3% (95% CI 72.7-91.1) for ECA-MRI and 68.1% (95% CI 56.0-78.6) for HBA-MRI. In terms of HCC diagnosis on ECA-MRI, 138 nodules had APHE, 84 had washout at PVP, and 104 at DP; on HBA-MRI, 128 nodules had APHE, 71 had washout at PVP, and 99 at HBP. For nodules 2-3 cm in size, sensitivity and specificity were similar between the 2 approaches. For nodules 1-2 cm in size, specificity dropped to 66.1% (95% CI 52.2-78.2) for HBA-MRI vs. 85.7% (95% CI 73.8-93.6) for ECA-MRI. CONCLUSIONS: HBA-MRI specificity is lower than that of ECA-MRI for diagnosing small HCCs in patients with cirrhosis. These results raise the question of the proper use of HBA-MRI in algorithms for the non-invasive diagnosis of small HCCs. LAY SUMMARY: There are 2 magnetic resonance imaging (MRI)-based approaches available for the non-invasive diagnosis of hepatocellular carcinoma (HCC), using either extracellular or hepatobiliary contrast agents. The current results showed that the sensitivity of MRI with hepatobiliary contrast agents was similar to that with extracellular contrast agents, but the specificity was lower. Thus, hepatobiliary contrast agent-based MRI, although detailed in international guidelines, should be used with caution for the non-invasive diagnosis of HCC. CLINICAL TRIAL NUMBER: NCT00848952.

Prevalence, features and predictive factors of liver nodules in Fontan surgery patients: The VALDIG Fonliver prospective cohort.

BACKGROUND & AIMS: Fontan surgery is used to treat a variety of congenital heart malformations, and may lead to advanced chronic liver disease in the long-term. This study examines the prevalence, characteristics and predictors of liver nodules in patients following Fontan surgery. METHODS: This was a prospective, cross-sectional, observational study conducted at 8 European centres. Consecutive patients who had undergone Fontan surgery underwent blood tests, abdominal ultrasonography (US), transient elastography (Fibroscan®), echocardiography, haemodynamic assessments, and abdominal MRI/CT scan. The primary outcome measure was liver nodules detected in the MRI/CT scan. Predictors of liver nodules were identified by multivariate logistic regression. RESULTS: One hundred and fifty-two patients were enrolled (mean age 27.3 years). The mean time elapsed from surgery to inclusion was 18.3 years. Liver nodule prevalences were 29.6% (95% CI 23-37%) on US and 47.7% (95% CI 39-56%) on MRI/CT. Nodules were usually hyperechoic (76.5%), round-shaped (>80%), hyperenhancing in the arterial phase (92%) and located in the liver periphery (75%). The sensitivity and specificity of US were 50% (95% CI 38-62%) and 85.3% (95% CI 75-92%), respectively. Inter-imaging test agreement was low (adjusted kappa: 0.34). In the multivariate analysis, time since surgery >10 years was the single independent predictor of liver nodules (odds ratio 4.18; p = 0.040). Hepatocellular carcinoma was histologically diagnosed in 2 of the 8 patients with hypervascular liver nodules displaying washout. CONCLUSION: While liver nodules are frequent in Fontan patients, they may go unnoticed in US. Liver nodules are usually hyperechoic, hypervascular and predominantly peripheral. This population is at risk of hepatocellular carcinoma, the diagnosis of which requires confirmatory biopsy. LAY SUMMARY: Fontan surgery is the standard of care for many patients with univentricular congenital cardiopathies. Recent advances have improved the survival of Fontan patients, and nowadays most of them reach adulthood. In this setting, Fontan-associated liver disease (FALD) is increasingly recognised, and has become a significant prognostic factor. Liver nodules are considered a component of FALD yet their prevalence, imaging features and predictors have hardly been evaluated. In this study, we observed that liver nodules are frequent, typically hyperechoic, hypervascular and predominantly peripheral in patients with FALD. This population is at risk of hepatocellular carcinoma, the diagnosis of which must be confirmed by biopsy.

Low specificity of washout to diagnose hepatocellular carcinoma in nodules showing arterial hyperenhancement in patients with Budd-Chiari syndrome.

BACKGROUND & AIMS: It remains unclear whether the classic imaging criteria for the non-invasive diagnosis of hepatocellular carcinoma (HCC) can be applied to chronic vascular liver diseases, such as Budd-Chiari syndrome (BCS). Herein, we aimed to evaluate the diagnostic value of washout for the discrimination between benign and malignant lesions in patients with BCS. METHODS: This retrospective study included all patients admitted to our institution with a diagnosis of BCS and focal lesions on MRI from 2000 to 2016. MRI images were reviewed by 2 radiologists blinded to the nature of the lesions. Patient and lesion characteristics were recorded, with a focus on washout on portal venous and/or delayed phases. Lesions were compared using Chi-square, Fisher's, Student's t or Mann-Whitney U tests. RESULTS: A total of 49 patients (mean age 35 ±â€¯12 years; 34 women [69%] and 15 men [31%]) with 241 benign lesions and 12 HCC lesions were analyzed. Patients with HCC were significantly older (mean age 44 ±â€¯16 vs. 33 ±â€¯9 years, p = 0.005), with higher alpha-fetoprotein (AFP) levels (median 16 vs. 3 ng/ml, p = 0.007). Washout was depicted in 9/12 (75%) HCC, and 69/241 (29%) benign lesions (p <0.001). A total of 52/143 (36%) lesions ≥1 cm with arterial hyperenhancement showed washout (9 HCC and 43 benign lesions). In this subgroup, the specificity of washout for the diagnosis of HCC was 67%. Adding T1-w hypointensity raised the specificity to 100%. A serum AFP >15 ng/ml was associated with 95% specificity. CONCLUSION: Washout was observed in close to one-third of benign lesions, leading to an unacceptably low specificity for the diagnosis of HCC. The non-invasive diagnostic criteria proposed for cirrhotic patients cannot be extrapolated to patients with BCS. LAY SUMMARY: Washout on MRI is depicted in a significant proportion of benign nodules in patients with Budd-Chiari syndrome (BCS), limiting its value for the differentiation between benign and malignant lesions. Criteria proposed for the non-invasive diagnosis of hepatocellular carcinoma in patients with cirrhosis cannot be extrapolated to patients with BCS. Additional imaging findings and patient characteristics, including alpha-fetoprotein serum level, can help determine the probability of a nodule being HCC in patients with BCS.

Evidence for an Association Between Intrahepatic Vascular Changes and the Development of Hepatopulmonary Syndrome.

BACKGROUND: Hepatopulmonary syndrome (HPS) is characterized by an arterial oxygenation defect, defined by an increased alveolar-arterial oxygen gradient, induced by pulmonary vascular dilatations in the context of liver disease. The pathogenesis of HPS is poorly understood. Morphologic changes associated with HPS are unknown. This study aimed at describing imaging and pathology changes associated with HPS. METHODS: We performed a case-control study in candidates for transplant with suspicion of cirrhosis. Each patient with HPS (Pao2 ≤ 70 mm Hg) was matched to three control subjects for age, cause, and liver disease severity. Pretransplant thoracic and abdominal imaging and explanted livers were reviewed. RESULTS: CT scans and Doppler ultrasounds from 21 patients with HPS were compared with those from 63 control subjects. HPS was associated with a two- to threefold higher prevalence of obstructed intrahepatic portal branches, of slowed or hepatofugal portal blood flow, and of large abdominal portosystemic shunts. Hepatic artery diameter was also larger in patients with HPS. Explanted livers from 19 patients with HPS were compared with those from 57 control subjects. HPS was associated with a fourfold higher prevalence of portal venule thrombosis and a ninefold higher prevalence of extensive vascular proliferation within fibrous septa. Obstruction of centrilobular venules, sinusoidal dilatation, and liver parenchymal extinction were also more common in patients with HPS. CONCLUSIONS: HPS is associated with intrahepatic vascular changes and with features suggesting severe portal hypertension. These results raise the hypothesis that intrahepatic vascular changes precipitate the development of HPS, opening new therapeutic perspectives for HPS.

Diagnosis of Budd-Chiari syndrome.

Budd-Chiari syndrome (BCS) is defined by clinical and laboratory signs associated with partial or complete impairment of hepatic venous drainage in the absence of right heart failure or constrictive pericarditis. Primary BCS is the most frequent type and is a complication of hypercoagulable states, in particular myeloproliferative neoplasms. Secondary BCS involves tumor invasion or extrinsic compression. Most patients present with chronic BCS including a non-cirrhotic, dysmorphic, chronic liver disease with various degrees of fibrosis deposition. Acute BCS is rare, and patients present with hepatomegaly, ascites, and hepatic insufficiency. The diagnosis is based on imaging. Imaging features include (1) direct signs, in particular occlusion or compression of the hepatic veins and/or the inferior vena cava and venous collaterals and (2) indirect signs, in particular morphological changes in the liver with hypertrophy of the caudate lobe and delayed nodule formation. Ultrasound and magnetic resonance imaging are the gold standard for diagnosis. The aim of this review is to provide an overview of the role of imaging in the diagnosis of BCS.

Correlation of tumor response on computed tomography with pathological necrosis in hepatocellular carcinoma treated by chemoembolization before liver transplantation.

The purpose of this article was to compare the results of Response Evaluation Criteria in Solid Tumors (RECIST), modified Response Evaluation Criteria in Solid Tumors (mRECIST), and European Association for the Study of the Liver (EASL) criteria for the evaluation of tumor necrosis in patients treated with transarterial chemoembolization before liver transplantation (LT) for hepatocellular carcinoma. Response to treatment was evaluated on computed tomography scan by 2 independent readers based on RECIST, mRECIST, and EASL criteria, and compared with tumor necrosis assessed by explant pathology. Necrosis was defined as major when >90%. Factors associated with major necrosis were tested by multivariate analysis. Fifty-eight patients (53 males; mean age, 54 years; range, 31-64 years) were included with 88 nodules. Fifty-one (58%) nodules were shown to have major necrosis. Among them readers 1 and 2 identified a complete response (CR) according to RECIST, mRECIST, and EASL criteria in 2 (4%), 47 (92%), and 47 (92%), and 1 (2%), 45 (88%), and 45 (88%) nodules, respectively. However, 12-14 of 59 nodules classified as CR on mRECIST or EASL criteria were found to have intermediate or minor necrosis (overestimation in 20%-24% of the patients). Combining the classification of CR by mRECIST and EASL criteria and complete lipiodol deposition reduced the overestimation to 11%. Among 59 nodules classified with a CR according to mRECIST or EASL, those with complete lipiodol deposition (n = 36, 61%) had a higher rate of necrosis than those with incomplete lipiodol deposition (n = 23, 39%): 95% versus 68% and 95% versus 63% for reader 1 and 2, respectively. In conclusion, CR based on mRECIST/EASL combined with complete lipiodol deposition was better for identification of major tumor necrosis. Even in the presence of CR according to mRECIST/EASL, incomplete lipiodol deposition should be considered indicative of substantial viable tumor remnant. Liver Transplantation 22 1491-1500 2016 AASLD.

Management of large hepatocellular carcinoma by sequential transarterial chemoembolization and portal vein embolization: a systematic review of the literature.

INTRODUCTION: Currently, the treatment of HCC is multidisciplinary. Surgery remains the gold standard although the management of large hepatocellular carcinoma remains challenging. Hepatic resection is increasingly performed with ever-expanding indications. However, postoperative liver failure remains a major cause of death after major hepatic resections. The purpose of this review is to report the results of large hepatocellular carcinoma (>5 cm or more nodules in the same lobe) management using sequential transarterial chemoembolization (TACE) and portal vein embolization (PVE) before major liver resections. EVIDENCE ACQUISITION: A literature search was performed using PubMed, Scopus, and Web of Science (WoS) from cited English publications. The search was last conducted in December 2014. Search phrases included "hepatocellular carcinoma", "liver resection", "transarterial chemoembolization", and "portal vein embolization". Clinical and survival parameters were extracted. When there was more than one publication from the same surgical team and/or authors, only the last publication in chronological order was considered for the study. Case reports, abstracts, letters, editorials, and expert opinions were not considered for the drafting of the study. After application of selective criteria, only 4 original studies were analyzed. EVIDENCE SYNTHESIS: No meta-analyses were found in the search. Among the 4 selected publications, 3 originated from Asia and 1 from Europe. The total number of patients treated with the method considered was 171 (range: 18-71). The mean size of the tumor was >5 cm. The gain of volume of the future remnant liver (FRL) was higher in the group with TACE+PVE as compared to the group with PVE alone (12% vs. 8%). A major hepatectomy was carried out in 166 patients (97%). Mortality rate ranged between 0% and 11%. The 5-year overall survival was between 43% and 72% and the 5-year recurrence-free survival was between 37% and 61%. CONCLUSIONS: Sequential TACE+PVE prior to a major hepatectomy for HCC was feasible, safe, and with excellent 5-year overall survival rates reported to be between 43% and 72%.

Post-hepatectomy liver failure: Should we consider venous outflow?

INTRODUCTION: Post-hepatectomy liver failure (PHLF) is one of the most serious complications of liver resection and is associated with high morbidity and mortality rates. PRESENTATION OF CASE: We report a case of PHLF involving clinical presentation of posthepatectomy-related 'small-for-size' syndrome (SFSS) secondary to obstructed venous outflow in the liver remnant, following extended right hepatectomy. DISCUSSION: PHLF is similar to SFSS in liver transplantation (LT) in terms of pathogenesis, clinical presentation and outcomes. Although inflow hypertension is clearly implicated in the pathogenesis of SFSS some authors have suggested that outflow obstruction is a potential pathogenic factor. CONCLUSION: The present case support the hypothesis that outflow obstruction could lead symptoms similar to SFSS.

Liver hilar abscesses secondary to gastrointestinal perforation by ingested fish bones: surgical management of two cases.

Several hepatobiliary complications secondary to gastrointestinal perforation after ingestion of a fish bone have been described in the literature, the most common being liver abscess, which can be potentially fatal. Treatment involves removal of the foreign body if possible (endoscopically or surgically), drainage of the abscess (radiologically or surgically), and appropriate antibiotic therapy. To our knowledge, no cases of hepatic hilar abscesses secondary to gastrointestinal perforation by a fish bone have been described in the literature. We report surgical management of two cases of abscess localized in the hepatic hilum secondary to the ingestion of fish bones.

Alternative Response Criteria (Choi, European association for the study of the liver, and modified Response Evaluation Criteria in Solid Tumors [RECIST]) Versus RECIST 1.1 in patients with advanced hepatocellular carcinoma treated with sorafenib.

INTRODUCTION: Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST 1.1), may underestimate activity and does not predict survival in patients with hepatocellular carcinoma (HCC) treated with sorafenib. This study assessed the value of alternative radiological criteria to evaluate response in HCC patients treated with sorafenib. PATIENTS AND METHODS: A retrospective blinded central analysis was performed of computed tomography (CT) scans from baseline and the first tumor evaluation in consecutive patients treated with sorafenib over a 2-year period in a single institution. Four different evaluation criteria were used: Choi, European Association for the Study of the Liver (EASL), modified RECIST (mRECIST), and RECIST 1.1. RESULTS: Among 82 HCC patients, 64 with Barcelona Clinic Liver Cancer stage B-C were evaluable with a median follow-up of 22 months. Median duration of sorafenib treatment was 5.7 months, and median overall survival was 12.8 months. At the time of the first CT scan, performed after a median of 2.1 months, Choi, EASL, mRECIST, and RECIST 1.1 identified 51%, 28%, 28%, and 3% objective responses, respectively. Responders by all criteria showed consistent overall survival >20 months. Among patients with stable disease according to RECIST 1.1, those identified as responders by Choi had significantly better overall survival than Choi nonresponders (22.4 vs. 10.6 months; hazard ratio: 0.43, 95% confidence interval: 0.15-0.86, p = .0097). CONCLUSION: Choi, EASL, and mRECIST criteria appear more appropriate than RECIST 1.1 to identify responders with long survival among advanced HCC patients benefiting from sorafenib.

Repeat endovascular treatment of recurring hepatic artery stenoses in orthotopic liver transplantation.

Hepatic artery stenosis (HAS) is a complication that impacts the results of orthotopic liver transplantation (OLT). Interventional radiological techniques are important therapeutic options for HAS. The aim of this retrospective study was to evaluate the outcome of repeated radiological treatments in recurring HAS after OLT. Of the 941 patients who underwent OLT at our center from January 1998 to September 2010, 48 (5%) were diagnosed with HAS, 37 (77%) of whom underwent transluminal interventional therapy with the placement of an endovascular stent. Success rate, complications, hepatic artery patency and follow-up were reviewed. After stent placement, artery patency was achieved in all patients. Three patients developed complications, including arterial dissection and hematoma. HAS recurrence was observed in 9 patients (24%), and hepatic artery thrombosis (HAT) occurred in 4 (11%). Radiological interventions were repeated 10 times in 8 patients without complications. At a median follow-up of 66 months (range 10-158), hepatic artery patency was observed in 35 cases (94.6%). The 5-year rates for graft and patient survival were 82.3% and 87.7%, respectively. Restenosis may occur in one-third of patients after endovascular treatment for thrombosis and HAS, but the long-term outcomes of iterative radiological treatment for HAS indicate a high rate of success.

Liver angulometry: a simple method to estimate liver volume and ratios.

OBJECTIVES: Volumetry is standard method for evaluating the volumes of the right liver (RL), left liver (LL), left lateral segments (LLS), total liver (TL) and future liver remnant (FLR). The aim of this study was to report a simple technique based on measurements of liver angles (angulometry) that can be used to predict liver ratios. METHODS: Fifty computed tomography (CT) scans obtained in subjects with normal liver were studied. Four CT scan levels were preselected: level 1 passed by the upper part of the hepatic veins; level 2 passed by the left portal vein branch division; level 3 passed by the right portal vein branch division, and level 4 passed by the gallbladder bed. Left and right tangent lines passing the liver edges were drawn and joined to the centre of the vertebra defining the TL angle. Two lines through, respectively, the plane of the middle hepatic vein and the left portal branches determined the angles of the RL, LL and LLS. Volumetric and angulometric data obtained on levels 2 and 3 in 50 different subjects were compared. RESULTS: Level 2 CT scans represented the most accurate way of obtaining angulometric measurements. The mean ± standard deviation (SD) angles of the TL and LL were 134 ± 12 ° and 55 ± 12 °, respectively. The mean ± SD percentages of the TL represented by the LL in angulometry and volumetry were 38 ± 7% and 36 ± 6%, respectively (non-significant difference). The mean ± SD percentages of the TL represented by the LLS in angulometry and volumetry were 25 ± 4% and 20 ± 3%, respectively (P < 0.05). The mean ± SD overestimation of the percentage of the TL represented by the LLS in angulometry was 2.7 ± 7.0%. CONCLUSIONS: Angulometry is a simple and accurate technique that can be used to estimate the ratio of the FLR to TL volume on one or two CT (or magnetic resonance imaging) slices. It can be helpful for clinicians, especially before right or extended right hepatectomy and after right portal vein occlusion techniques.

High sensitivity of diffusion-weighted MR imaging for the detection of liver metastases from neuroendocrine tumors: comparison with T2-weighted and dynamic gadolinium-enhanced MR imaging.

PURPOSE: To compare the sensitivity and specificity of diffusion-weighted (DW) magnetic resonance (MR) imaging for identifying liver metastases from neuroendocrine tumor (NET) to those of T2-weighted fast spin-echo (FSE) and three-dimensional dynamic gadolinium-enhanced MR imaging, with surgical and histopathologic findings as the reference standard. MATERIALS AND METHODS: This retrospective study was approved by institutional review board, and informed consent was waived. Fifty-nine patients with NETs (41 patients with 162 liver metastases, and 18 control subjects with no liver metastases) underwent MR imaging that included DW, T2-weighted FSE, and dynamic gadolinium-enhanced MR sequences. Images were retrospectively reviewed by two abdominal radiologists, independently, for the detection and characterization of liver metastases. MR findings were compared with histopathologic and intraoperative ultrasonography findings for metastasis on a lesion-by-lesion basis to determine the sensitivity of each MR sequence alone and combined. Specificity was calculated by using the control population. Interreader agreement for each MR sequence and McNemar test were also calculated. RESULTS: There was excellent agreement between observers 1 and 2 for characterizing liver metastases at per-lesion analysis (κ coefficient: 0.86-1.00). DW MR was more sensitive (observer 1: sensitivity, 71.6% [116 of 162], 95% confidence interval [CI]: 64.2%, 78.0%; observer 2: sensitivity, 71.0% [115 of 162], 95% CI: 63.6%, 77.4%) than T2-weighted FSE (observer 1: sensitivity, 55.6% [90 of 162], 95% CI: 47.9%, 63.0%; observer 2: sensitivity, 55.6% [90 of 162], 95% CI: 47.9%, 63.0%) and dynamic gadolinium-enhanced MR (observer 1: sensitivity, 47.5% [77 of 162], 95% CI: 34.0%, 55.2%; observer 2: sensitivity, 48.1% [78 of 162], 95% CI: 40.6%, 55.8%) (P < .001 for both, McNemar test). The specificity of these sequences ranged from 88.9% to 100% (DW MR vs T2-weighted FSE MR: P > .99, DW MR vs dynamic gadolinium-enhanced MR: P = .61, and T2-weighted FSE MR vs dynamic gadolinium-enhanced MR: P = .61, McNemar test). CONCLUSION: DW MR imaging was more sensitive for the detection and characterization of liver metastases from NETs than T2-weighted FSE and dynamic gadolinium-enhanced MR imaging and should be systematically performed.

Imaging response in neuroendocrine tumors treated with targeted therapies: the experience of sunitinib.

Among neuroendocrine carcinomas of the gut, well-differentiated tumors are highly vascularized, featuring specific characteristics on contrast-enhanced imaging. Well-differentiated neuroendocrine tumors spontaneously harbor hypervascular enhancement, coexisting with areas of necrosis mainly located at the center of tumor lesions. When exposed to vascular endothelial growth factor (VEGFR) inhibitors such as sunitinib, target lesions display few if any variation in tumor size, but rather detectable modifications in tumor density. In several patients treated with targeted therapy, a significant decrease of tumor density at first tumor evaluation can be detected as compared to baseline. Consistently, the two randomized trials leading to approval of sunitinib and everolimus in pancreatic neuroendocrine tumors report objective response rate below 10%, emphasizing that Response Evaluation Criteria in Solid Tumors (RECIST), that focus only on the largest diameters of target lesions, may be insufficient to capture the full benefit of targeted therapies. Alternative criteria, such as those developed by Choi et al., consider both the size and the density of the tumor as parameters for response evaluation. Choi criteria have been recently proposed as a surrogate endpoint for efficacy and to identify patients that are good responders to VEGFR inhibitors such as sunitinib and sorafenib in advanced hepatocellular carcinoma, another disease highly addicted to angiogenesis. Preliminary data generated from patients included in the sunitinib phase III trial suggest that Choi criteria might also be considered as an alternative to RECIST to evaluate the effects of sunitinib in patients with advanced well-differentiated neuroendocrine tumors.