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International audience; 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.

The purpose of our study was to correlate the quantitative analysis of benign hepatocellular tumor uptake on delayed hepatobiliary phase (HBP) imaging with the quantitative level of OATP expression. This single-center retrospective study, which took place between September 2009 and March 2015, included 20 consecutive patients with a proven pathologic and immunohistochemical (IHC) diagnosis of FNH or HCA, including quantification of the OATP expression. The patients underwent Gd-BOPTA-enhancement MRI, including an HBP. The analysis of HBP uptake was performed using the liver-to-lesion contrast enhancement ratio (LLCER). Mean LLCER and OATP expressions were compared between FNH and HCA, and the expression of OATP was correlated with the LLCER value. Of the 23 benign hepatocellular tumors, 9 (39%) were FNH and 14 (61%) were HCA, including 6 inflammatory, 2 HNF1a inactivated, 3 β-catenin-mutated and 3 unclassified HCAs. On HBP, 100% of the FNH appeared hyper- or isointense, and 79% of the adenomas appeared hypointense. The mean OATP expression of FNH (46.67 ± 26.58%) was significantly higher than that of HCA (22.14 ± 30.74%) (p = 0.0273), and the mean LLCER of FNH (10.66 ± 7.403%) was significantly higher than that of HCA (-13.5 ± 12.25%) (p < 0.0001). The mean LLCER of β-catenin-mutated HCA was significantly higher than that of other HCAs (p = 0.011). Significant correlation was found between the OATP expression and LLCER values (r = 0.661; p = 0.001). In benign hepatocellular tumors, the quantitative analysis of hepatobiliary contrast agent uptake on HBP is correlated with the level of OATP expression and could be used as an imaging biomarker of the molecular background of HCA and FNH. • Gd-BOPTA uptake on HBP correlates with the OATP level in benign hepatocellular tumors • FNH and β-catenin-mutated HCA showed an increased lesion-to-liver contrast enhancement ratio (LLCER) • Increased LLCER may be explained by activation of the Wnt β-catenin pathway

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.

Resume La prise en charge avant resection des lesions secondaires intra-hepatiques est multidisciplinaire, le role des radiologues et des medecins nucleaires y est majeur. Conformement au guide du bon usage des examens d’imagerie, l’approche doit etre multimodale : la tomodensitometrie thoraco-abdomino-pelvienne et l’IRM hepatique sont incontournables ; la TEP-TDM apporte des elements importants, notamment pour les metastases intra-abdominales extra-hepatiques. Cette approche multimodale souligne l’importance d’une prise en charge adaptee et precoce de ces patients en imagerie, ainsi que le role central des reunions de concertation pluridisciplinaire en oncologie.

Management of patients with a benign hepatocellular tumor relies largely on imaging data; the diagnosis of focal nodular hyperplasia (FNH) must be made with certainty using MRI, because no other clinical or laboratory data can help diagnosis. It is also essential to identify adenomas to manage them appropriately. The radiological report in these situations is therefore of major importance. However, there are diagnostic traps. The aim of this paper is to present the keys to the diagnosis of benign lesions and to warn of the main diagnostic pitfalls.

Diffusion-Weighted-Imaging (DWI) assesses proton motion on a cellular scale. Owing to recent instrumentation developments, diffusion sequences are now routinely used for liver imaging. This review will go through the physical principles that underlie this technique, and then highlight up-to-date liver applications including quantification of liver fibrosis, focal lesions detection and characterization, and therapy response monitoring.

OBJECTIVES The aim of this pilot study was to assess post-treatment apparent diffusion coefficient (ADC) changes of diffuse large B-cell lymphoma lesions on respiratory-gated whole-body diffusion-weighted imaging (DWI), with integrated (18)F-fluoro-2-deoxyglucose positron emission tomography/computed tomography (PET/CT) as the reference standard. MATERIALS AND METHODS A total of 15 patients underwent both whole-body DWI (b = 50, 400, 800 s/mm(2)) and PET/CT before initiation and after 4 cycles of chemotherapy. ADC of residual masses (lymph node and organ lesions) was assessed both visually and quantitatively, including measurement of mean ADC (ADC).(Figure is included in full-text article.) RESULTS After chemotherapy, among 85 examined lymph node regions, residual nodes were present in 62 (73%) regions on DWI. Of these 62 regions, 26 had persistent lymph nodes with longest transverse diameter >10 mm, ie, positive based on DWI size criteria. The mean ADC of these 26 regions increased from 0.658 × 10(-3) ± 0.153 mm(2)/s (standard deviation) at baseline to 1.501 × 10(-3) ± 0.307 mm(2)/s (paired t test, P < 0.0001). Only 6 of these 26 regions were considered positive on PET/CT. Combining visual ADC analysis to size criteria reduced the number of false-positive results of DWI from 20 to 2 regions. For organ involvement, ADC values also increased compared with baseline (1.558 × 10(-3) ± 0.424 mm(2)/s vs. 0.675 × 10(-3) ± 0.135 mm(2)/s, respectively; P = 0.0009). CONCLUSIONS Whole-body DWI with ADC mapping can show a significant increase in ADC values of residual masses persisting after treatment and may help to assess the treatment response in patients with diffuse large B-cell lymphoma.

Cirrhosis is a chronic liver disease characterized by the presence of diffuse parenchymal necrosis, reactive fibrosis and nodular regeneration. These regenerative nodules may evolve into dysplastic nodules and finally nodules of hepatocellular carcinoma (HCC). Improved survival of cirrhotic patients with HCC depends on eligibility to liver transplantation. The purpose of this paper is to review the imaging features of liver nodules within cirrhotic liver and to propose the imaging strategies when considering the possibility of liver transplantation.

Resume La decouverte de dilatations kystiques des voies biliaires intra-hepatiques en l’absence d’obstacle est rare. Dans cette circonstance, l’imagerie permet de distinguer les maladies fibro-kystiques hepatiques (ou les lesions kystiques communiquent avec les voies biliaires, telles que le syndrome de Caroli associe ou non a la fibrose hepatique congenitale) des maladies polykystiques du foie (ou aucune communication avec les voies biliaires n’est mise en evidence, telles que les polykystoses hepatiques ou hepatorenales autosomales dominantes). Les techniques de cholangiographie invasives sont desormais supplantees par la cholangio-pancreatographie par IRM. L’association en cholangio-pancreatographie par IRM de dilatations kystiques sacciformes ou fusiformes des voies biliaires intra-hepatiques et d’un axe fibro-vasculaire central (signe central du point) evoque le diagnostic de syndrome de Caroli. La presence de signes surajoutes de dysmorphie hepatique, incluant une atrophie du foie droit ou une hypertrophie du segment IV, en l’absence d’autre etiologie nette suggere l’association a une fibrose hepatique congenitale. L’aspect de ces maladies fibro-kystiques en cholangio-pancreatographie par IRM, mais egalement en echo-Doppler ou en tomodensitometrie, est bien correle a l’existence d’un defaut embryologique de maturation de la plaque ductale.

ejd.2011.1538 Auteur(s) : Claire Hotz1,a q claire.hotz@gmail.com, Saskia Ingen-Housz-Oro1,a, Jeanne Tran Van Nhieu2, Caroline Charlier3, Francoise Foulet4, Alain Rahmouni5, Benhalima Zegai5, Tu-Anh Duong1, Pierre Wolkenstein1, Martine Bagot6,a, Olivier Chosidow1,a 1 Department of Dermatology 2 Department of Pathology, Henri-Mondor hospital, 51 avenue du marechal-de-Lattre-de-Tassigny, 94010 Creteil, France 3 Department of Infectious Diseases, Necker–Enfants Malades Hospital, Paris, France 4 [...]

The management of colorectal intrahepatic metastases before resection is multidisciplinary and radiologists and nuclear medicine specialists play a major role. In accordance with the French National Guide for appropriate use of diagnostic imaging, the approach should be multimodal: a chest-abdomen and pelvic (CAP) CT scan and hepatic MRI are mandatory while PET-CT provides important additional information, in particular on intra-abdominal extrahepatic metastases. This multimodal approach emphasizes the importance of early and appropriate use of imaging in these patients, as well as the central role of multidisciplinary meetings in oncology.

Cirrhosis is a chronic liver disease characterized by the presence of diffuse parenchymal necrosis, reactive fibrosis and nodular regeneration. These regenerative nodules may evolve into dysplastic nodules and finally nodules of hepatocellular carcinoma (HCC). Improved survival of cirrhotic patients with HCC depends on eligibility to liver transplantation. The purpose of this paper is to review the imaging features of liver nodules within cirrhotic liver and to propose the imaging strategies when considering the possibility of liver transplantation.

Extramedullary haematopoiesis (EMH) is a reactive mechanism by which blood cells are produced outside of the bone marrow to supplement insufficient production or increased destruction of erythrocytes. EMH is uncommon in sickle cell anaemia (SCA). We report the first case of focal intra-hepatic EMH in SCA depicted on MRI occurring in a 32-year-old woman with homozygote SCA and in view of previously published data, highlight the diagnostic features suggesting a differential diagnosis with other focal liver lesions including infectious, inflammatory or primary liver tumors.

Objectifs Connaitre les principes techniques de l’IRM de diffusion, de perfusion et de quantification de la graisse appliquees a l’etude du foie. Connaitre les limites technologiques de l’evaluation fonctionnelle non-invasive du foie. Connaitre les indications des techniques d’IRM d’evaluation fonctionnelle du foie. Messages a retenir Les sequences de diffusion peuvent etre optimisees pour l’etude d’organes mobiles comme le foie. L’etude de la diffusion et de la perfusion hepatique peut apporter des informations fonctionnelles utiles pour le diagnostic et le suivi non-invasif des hepatopathies chroniques. La place des techniques IRM de quantification dans l’etude non-invasive des maladies du foie reste a preciser. Resume Les sequences d’IRM de diffusion, notamment asservies a la respiration, constituent un outil d’evaluation non invasif de la fibrose hepatique. Le choix du facteur b influence directement les parametres physiopathologiques evalues. La quantification de la graisse par les sequences de type DIXON ou spectroscopiques est possible en IRM : la prevalence des hepatopathies steatosiques (NAFLD) est en augmentation et oscille actuellement entre 10 a 30% de la population occidentale. Le developpement recent de nouvelles therapeutiques anti-fibrosantes et anti-steatosique necessite l’optimisation des techniques de suivi non-invasif de la steatose.

Objectifs Connaitre les elements diagnostiques caracteristiques de l’hyperplasie nodulaire focale en imagerie. Connaitre la strategie diagnostique de l’hyperplasie nodulaire focale. Connaitre les elements semiologiques fondamentaux anatomopathologiques. Connaitre les atypies en imagerie et en anatomopathologie de l’HNF. Messages a retenir L’IRM est l’examen fondamental permettant la caracterisation formelle de l’hyperplasie nodulaire focale dans sa forme typique. L’echographie de contraste, par l’identification d’une cinetique de rehaussement central, centrifuge peut permettre une distinction entre hyperplasie nodulaire focale et adenome. Les elements anatomopathologiques caracteristiques de l’hyperplasie nodulaire focale sont la presence de bandes fibreuses inflammatoires contenant des structures vasculaires dystrophiques, associee a une proliferation cholangiolaire delimitant plus ou moins completement des nodules d’hepatocytes normaux. Resume Le diagnostic de l’hyperplasie nodulaire focale typique repose sur les donnees de l’IRM, permettant d’identifier une lesion homogene, en faible hypersignal T2, avec une zone stellaire centrale en hypersignal T2, une cinetique de rehaussement precoce, homogene, et le rehaussement tardif d’une zone stellaire centrale et l’absence de capsule peri-lesionnelle. La presence en echographie de contraste d’un rehaussement precoce intense, generalement alimente par une artere centrale et progressant de facon centrifuge est un element diagnostique important. L’aspect macroscopique est evocateur lorsqu’il montre un nodule hepatocytaire bien delimite du reste du parnchyme mais non encapsule, fait lui-meme de nodules confluents et centre par un element fibreux etoile. Le diagnostic histopathologique formel repose sur l’association d’elements caracteristiques que sont les bandes fibreuses contenant des vaisseaux a parois dystrophiques et delimitant plus ou moins completement des nodules d’hepatocytes reguliers, la presence d’une inflammation mononucleee et d’une proliferation. Certaines atypies histopathologiques telles qu’une steatose marquee, la rarete des bandes fibreuses ou de l’infiltrat inflammatoire, ou encore des atypies cyto-nucleaires peuvent poser un probleme de diagnostic differentiel avec d’autres lesions hepatocytaires, en particulier les adenomes voire les carcinomes hepatocellulaires.

Objectifs Concevoir une sequence d’IRM ponderee en diffusion (IVIM-DWI) adaptee au foie avec synchronisation respiratoire et acquisition parallele, permettant d’extraire et de comparer les parametres de diffusion pure (D) et de microperfusion intravoxel (D*, f) sur des foies sains et cirrhotiques. Materiels et methodes Une sequence IVIM-DWI avec 10 pas de b (0,10, 20,30, 50,80, 100,200, 400,800 s/mm2) a ete validee sur fantomes. Une IRM hepatique incluant cette sequence IVIM-DWI a ete realisee chez 12 patients porteurs de cirrhose documentee et 25 sujets sains. Les valeurs D, D*, f et le coefficient apparent de diffusion (ADC) calcule sur 4 pas de b ont ete comparees dans les 2 groupes (t-test). Resultats La decroissance du signal hepatique etait biexponentielle correspondant a une double composante de la diffusion dans le foie. Les valeurs moyennes d’ADC etaient superieures aux valeurs de D (p Conclusion La restriction de la diffusion observee dans les foies de cirrhose s’accompagne d’une diminution de sa composante microperfusive.

Objectifs Connaitre la semeiologie des differents nodules sur hepa-topathie chronique. Connaitre les criteres diagnostiques de carcinome hepatocellulaire (CHC) en imagerie. Connaitre les elements clefs du compte rendu. Points cles La recherche de signes d’hepatopathie chronique est la premiere etape du raisonnement lors de la caracterisation d’un nodule hepatique. Les lesions nodulaires sur foie d’hepatopathie chronique incluent : nodule de regeneration, nodule dysplasique, CHC, fibrose confluante et troubles de perfusion. En imagerie, les criteres diagnostiques du CHC sont la taille et le profil vasculaire.

Objectifs pedagogiques Connaitre les performances des differentes modalites d’imagerie (echographie, TDM, IRM) pour la detection des nodules sur foie de cirrhose. Savoir reconnaitre les elements semeiologiques orientant vers une complication tumorale (CHC). Connaitre l’interet des combinaisons de modalites d’imagerie. Connaitre les elements determinants du compte rendu radiologique.