Liver imaging and pregnancy: what to expect when your patient is expecting.

Liver diseases in pregnancy can be specific to gestation or only coincidental. In the latter case, the diagnosis can be difficult. Rapid diagnosis of maternal-fetal emergencies and situations requiring specialized interventions are crucial to preserve the maternal liver and guarantee materno-fetal survival. While detailed questioning of the patient and a clinical examination are highly important, imaging is often essential to reach a diagnosis of these liver diseases and lesions. Three groups of liver diseases may be observed during pregnancy: (1) diseases related to pregnancy: intrahepatic cholestasis of pregnancy, pre-eclampsia, eclampsia, hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome, and acute fatty liver of pregnancy; (2) liver diseases that are more frequent during or exacerbated by pregnancy: acute herpes simplex hepatitis, Budd-Chiari syndrome, hemorrhagic hereditary telangiectasia, hepatocellular adenoma, portal vein thrombosis, and cholelithiasis; (3) coincidental conditions, including acute hepatitis, incidental focal liver lesions, metabolic dysfunction-associated steatotic liver disease, cirrhosis, hepatocellular carcinoma, liver abscesses and parasitosis, and liver transplantation. Specific knowledge of the main imaging findings is required to reach an early diagnosis, for adequate follow-up, and to avoid adverse consequences in both the mother and the fetus.Critical relevance statement Pregnancy-related liver diseases are the most important cause of liver dysfunction in pregnant patients and, in pregnancy, even common liver conditions can have an unexpected turn. Fear of radiations should never delay necessary imaging studies in pregnancy.Key points• Pregnancy-related liver diseases are the most frequent cause of liver dysfunction during gestation.• Fear of radiation should never delay necessary imaging studies.• Liver imaging is important to assess liver emergencies and for the diagnosis and follow-up of any other liver diseases.• Common liver conditions and lesions may take an unexpected turn during pregnancy.• Pregnancy-specific diseases such as pre-eclampsia and HELLP syndrome must be rapidly identified. However, imaging should never delay delivery when it is considered to be urgent for maternal-fetal survival.

A mutation-based radiomics signature predicts response to imatinib in Gastrointestinal Stromal Tumors (GIST).

Objectives: To develop a mutation-based radiomics signature to predict response to imatinib in Gastrointestinal Stromal Tumors (GISTs). Methods: Eighty-two patients with GIST were enrolled in this retrospective study, including 52 patients from one center that were used to develop the model, and 30 patients from a second center to validate it. Reference standard was the mutational status of tyrosine-protein kinase (KIT) and platelet-derived growth factor α (PDGFRA). Patients were dichotomized in imatinib sensitive (group 0 - mutation in KIT or PDGFRA, different from exon 18-D842V), and imatinib non-responsive (group 1 - PDGFRA exon 18-D842V mutation or absence of mutation in KIT/PDGFRA). Initially, 107 texture features were extracted from the tumor masks of baseline computed tomography scans. Different machine learning methods were then implemented to select the best combination of features for the development of the radiomics signature. Results: The best performance was obtained with the 5 features selected by the ANOVA model and the Bayes classifier, using a threshold of 0.36. With this setting the radiomics signature had an accuracy and precision for sensitive patients of 82 % (95 % CI:60-95) and 90 % (95 % CI:73-97), respectively. Conversely, a precision of 80 % (95 % CI:34-97) was obtained in non-responsive patients using a threshold of 0.9. Indeed, with the latter setting 4 patients out of 5 were correctly predicted as non-responders. Conclusions: The results are a first step towards using radiomics to improve the management of patients with GIST, especially when tumor tissue is unavailable for molecular analysis or when molecular profiling is inconclusive.

Budd-Chiari Syndrome Imaging Diagnosis: State of the Art and Future Perspectives.

Budd-Chiari syndrome (BCS) is a rare hepatic vascular disorder defined by the presence of partial or complete impairment of hepatic venous drainage in the absence of right heart failure or constrictive pericarditis. Several conditions can lead to BCS, from hypercoagulable states to malignancies. Primary BCS is the most common subtype, and usually bartends hypercoagulability states, while secondary BCS involves tumor invasion or extrinsic compression. A combination of clinical and imaging features leads to the diagnosis of BCS, including (1) direct signs: occlusion or compression of the hepatic veins and/or inferior vena cava, and the presence of venous collaterals; (2) indirect signs: morphological hepatic changes with caudate lobe enlargement; inhomogeneous enhancement, and hypervascular nodules. From a clinicopathological point of view, two forms of BCS can be distinguished: acute and subacute/chronic BCS, although asymptomatic and fulminant forms are also possible. Acute presentations are rare, and symptoms include hepatomegaly, ascites, and hepatic insufficiency. Subacute/chronic forms are the most common presentation, with dysmorphic liver and variable degrees of fibrosis deposition. Patients with chronic BCS can develop benign regenerative nodules (large regenerative nodules or FNH [Focal Nodular Hyperplasia]-like lesions), but are also at a higher risk of hepatocellular carcinoma (HCC). The radiologist role is therefore fundamental in both diagnosis and surveillance of BCS. The aim of this review is to present all clinical and imaging signs that can help to reach the diagnosis of BCS, with their clinical significance, providing tips and tricks for the cross-sectional diagnosis of this condition.

CT and MR Imaging of Retroperitoneal Sarcomas: A Practical Guide for the Radiologist.

Primary retroperitoneal sarcomas (RPS) represent around 10-16% of all sarcomas, with liposarcomas and leiomyosarcomas being the most common subtypes. RPS have some peculiar characteristics, imaging appearances, worse prognosis, and complications compared to other locations of sarcoma. Commonly, RPS primarily present as large masses, progressively encasing adjacent structures, causing mass effect, and complications. RPS diagnosis is often challenging, and these tumors may be overlooked; however, failure to recognize RPS characteristics leads to a worse prognosis for the patients. Surgery is the only recognized curative treatment, but the anatomical constraints of the retroperitoneum limit the ability to achieve wide resection margins; therefore, these tumors have a high rate of recurrence, and require long-term follow-up. The radiologist has an important role in the diagnosis of RPS, the definition of their extent, and their follow-up. Specific knowledge of the main imaging findings is required to reach an early diagnosis, and, ultimately, to guarantee the best patient management. This article provides an overview of the current knowledge regarding cross-sectional imaging features of patients with retroperitoneal sarcomas, presenting tips and tricks to improve imaging diagnosis of RPS.

Imaging of hepatocellular carcinoma recurrence after liver transplantation.

Liver transplantation (LT) provides the highest survival benefit to patients with unresectable hepatocellular carcinoma (HCC). The Milan criteria have been developed for the selection of LT candidates with the goal of improving survival and maintaining an acceptable risk of HCC recurrence. Despite this, recurrence of HCC after LT occurs in up to 20% of cases and represents a major concern due to the poor prognosis of these patients. Furthermore, several extended criteria for the selection of LT candidates have been proposed to account for the growing demand for organs and the resultant increase in the risk of HCC recurrence. Radiologists should be aware that HCC can recur after LT with multiple organ involvement. Knowledge of the location and radiologic appearance of recurrent HCC is necessary to ensure the choice of the most appropriate therapy. This paper aims to comprehensively summarize the spectrum of HCC recurrence after LT and to examine and discuss the imaging features of these lesions. CRITICAL RELEVANCE STATEMENT: This paper aims to share a review of imaging findings of HCC recurrence after LT and to make radiologists familiar with the spectrum of this disease.

Volumetric Enhancing Tumor Burden at CT to Predict Survival Outcomes in Patients with Neuroendocrine Liver Metastases after Intra-arterial Treatment.

Purpose To investigate whether liver enhancing tumor burden (LETB) assessed at contrast-enhanced CT indicates early response and helps predict survival outcomes in patients with multifocal neuroendocrine liver metastases (NELM) after intra-arterial treatment. Materials and Methods This retrospective study included patients with NELM who underwent intra-arterial treatment with transarterial embolization (TAE) or chemoembolization (TACE) between April 2006 and December 2018. Tumor response in treated NELM was evaluated by using the Response Evaluation Criteria in Solid Tumors (RECIST) and modified RECIST (mRECIST). LETB was measured as attenuation 2 SDs greater than that of a region of interest in the nontumoral liver parenchyma. Overall survival (OS); time to unTA(C)Eable progression, defined as the time from the initial treatment until the time when intra-arterial treatments were considered technically unfeasible, either not recommended by the multidisciplinary tumor board or until death; and hepatic and whole-body progression-free survival (PFS) were evaluated using multivariable Cox proportional hazards analyses, the Kaplan-Meier method, and log-rank test. Results The study included 119 patients (mean age, 60 years ± 11 [SD]; 61 men) who underwent 161 treatments. A median LETB change of -25.8% best discriminated OS (83 months in responders vs 51 months in nonresponders; P = .02) and whole-body PFS (18 vs 8 months, respectively; P < .001). A -10% LETB change best discriminated time to unTA(C)Eable progression (32 months in responders vs 12 months in nonresponders; P < .001) and hepatic PFS (18 vs 8 months, respectively; P < .001). LETB change remained independently associated with improved OS (hazard ratio [HR], 0.56), time to unTA(C)Eable progression (HR, 0.44), hepatic PFS (HR, 0.42), and whole-body PFS (HR, 0.47) on multivariable analysis. Neither RECIST nor mRECIST helped predict patient outcome. Conclusion Response according to LETB change helped predict survival outcomes in patients with NELM after intra-arterial treatments, with better discrimination than RECIST and mRECIST. Keywords: CT, Chemoembolization, Embolization, Abdomen/GI, Liver Supplemental material is available for this article. © RSNA, 2023.

The Neoplastic Side of the Abdominal Wall: A Comprehensive Pictorial Essay of Benign and Malignant Neoplasms.

Abdominal wall neoplasms are usually benign and, in the majority of these cases, no further work-up or treatment is indicated. The percentage of malignant abdominal neoplasms, however, is not negligible. Radiologists play a pivotal role in identifying imaging features that should favor malignancy, including larger lesion size, edema, neurovascular involvement, and peripheral or inhomogeneous dynamic enhancement, thus indicating to the clinician the need for further work-up. Histopathology is the reference standard for the characterization of abdominal wall neoplasms. In patients undergoing surgery, radiological assessment is needed to guide the surgeon by providing a comprehensive anatomic guide of the tumor extension. We present a pictorial review of benign and malignant abdominal wall neoplasms that can be encountered on radiological examinations, with a main focus on CT and MRI features that help in narrowing the differential diagnosis.

The Benign Side of the Abdominal Wall: A Pictorial Review of Non-Neoplastic Diseases.

The abdominal wall is the location of a wide spectrum of pathological conditions, from benign to malignant ones. Imaging is often recommended for the evaluation of known palpable abdominal masses. However, abdominal wall pathologies are often incidentally discovered and represent a clinical and diagnostic challenge. Knowledge of the possible etiologies and complications, combined with clinical history and laboratory findings, is crucial for the correct management of these conditions. Specific imaging clues can help the radiologist narrow the differential diagnosis and distinguish between malignant and benign processes. In this pictorial review, we will focus on the non-neoplastic benign masses and processes that can be encountered on the abdominal wall on cross-sectional imaging, with a particular focus on their management. Distinctive sonographic imaging clues, compared with computed tomography (CT) and magnetic resonance (MR) findings will be highlighted, together with clinical and practical tips for reaching the diagnosis and guiding patient management, to provide a complete diagnostic guide for the radiologist.

Assessment of morphological CT imaging features for the prediction of risk stratification, mutations, and prognosis of gastrointestinal stromal tumors.

OBJECTIVES: To investigate the correlation between CT imaging features and risk stratification of gastrointestinal stromal tumors (GISTs), prediction of mutation status, and prognosis. METHODS: This retrospective dual-institution study included patients with pathologically proven GISTs meeting the following criteria: (i) preoperative contrast-enhanced CT performed between 2008 and 2019; (ii) no treatments before imaging; (iii) available pathological analysis. Tumor risk stratification was determined according to the National Institutes of Health (NIH) 2008 criteria. Two readers evaluated the CT features, including enhancement patterns and tumor characteristics in a blinded fashion. The differences in distribution of CT features were assessed using univariate and multivariate analyses. Survival analyses were performed by using the Cox proportional hazard model, Kaplan-Meier method, and log-rank test. RESULTS: The final population included 88 patients (59 men and 29 women, mean age 60.5 ± 11.1 years) with 45 high-risk and 43 low-to-intermediate-risk GISTs (median size 6.3 cm). At multivariate analysis, lesion size ≥ 5 cm (OR: 10.52, p = 0.009) and enlarged feeding vessels (OR: 12.08, p = 0.040) were independently associated with the high-risk GISTs. Hyperenhancement was significantly more frequent in PDGFRα-mutated/wild-type GISTs compared to GISTs with KIT mutations (59.3% vs 23.0%, p = 0.004). Ill-defined margins were associated with shorter progression-free survival (HR 9.66) at multivariate analysis, while ill-defined margins and hemorrhage remained independently associated with shorter overall survival (HR 44.41 and HR 30.22). Inter-reader agreement ranged from fair to almost perfect (k: 0.32-0.93). CONCLUSIONS: Morphologic contrast-enhanced CT features are significantly different depending on the risk status or mutations and may help to predict prognosis. KEY POINTS: • Lesions size ≥ 5 cm (OR: 10.52, p = 0.009) and enlarged feeding vessels (OR: 12.08, p = 0.040) are independent predictors of high-risk GISTs. • PDGFRα-mutated/wild-type GISTs demonstrate more frequently hyperenhancement compared to GISTs with KIT mutations (59.3% vs 23.0%, p = 0.004). • Ill-defined margins (hazard ratio 9.66) were associated with shorter progression-free survival at multivariate analysis, while ill-defined margins (hazard ratio 44.41) and intralesional hemorrhage (hazard ratio 30.22) were independently associated with shorter overall survival.

Abdominal splenosis and its differential diagnoses: What the radiologist needs to know.

Splenosis is a benign acquired condition characterized by the presence of heterotopic viable splenic tissue in other organs or within cavities such as peritoneum, retroperitoneum, or thorax after splenic trauma or surgery. Abdominal splenosis is often an incidental finding and computed tomography and magnetic resonance usually allow a confident diagnosis. The typical enhancement that parallels the spleen is a useful hallmark of splenosis. Splenic implants lack contrast uptake in the hepatobiliary phase and show high signal at high b-values on diffusion-weighted images. In some cases splenosis may mimic malignant and benign conditions in the peritoneum as well as in hollow and parenchymal abdominal organs and further investigations - including scintigraphy with Tc99m-labelled heat-denatured red blood cells or biopsy - are sometimes required in challenging cases. This pictorial essay reviews the imaging presentation and potential differential diagnosis of splenosis according to the site of implantation. A prompt and accurate radiological diagnosis of splenosis can avoid unnecessary biopsy or surgery.

Benign and malignant mimickers of infiltrative hepatocellular carcinoma: tips and tricks for differential diagnosis on CT and MRI.

Hepatocellular carcinoma (HCC) may have an infiltrative appearance in about 8-20% of cases. Infiltrative HCC can be a challenging diagnosis and it is associated with the worst overall survival among HCC patients. Infiltrative HCC is characterized by the spread of multiple minute nodules throughout the liver, without a dominant one, ultimately resulting into macrovascular invasion. On CT and MRI, infiltrative HCC appears as an ill-defined, large mass, with variable degree of enhancement, and satellite neoplastic nodules in up to 52% of patients. On MRI, it may show restriction on diffusion weighted imaging, hyperintensity on T2- and hypointensity on T1-weighted images, and, if hepatobiliary agent is used, hypointensity on hepatobiliary phase. Infiltrative HCC must be differentiated from other liver diseases, such as focal confluent fibrosis, steatosis, amyloidosis, vascular disorders of the liver, cholangiocarcinoma, and diffuse metastatic disease. In cirrhotic patients, the identification of vascular tumor invasion of the portal vein and its differentiation from bland thrombosis is of utmost importance for patient management. On contrast enhanced CT and MRI, portal vein tumor thrombosis appears as an enhancing thrombus within the portal vein, close to the main tumor and results into vein enlargement. The aim of this pictorial review is to show CT and MRI features that allow the diagnosis of infiltrative HCC and portal vein tumor thrombosis. A particular point of interest includes the tips and tricks for differential diagnosis with potential mimickers of infiltrative HCC.

Focal liver lesions: interobserver and intraobserver agreement of three-dimensional contrast-enhanced ultrasound-assisted volume measurements.

PURPOSE: This study was conducted to assess the interobserver and intraobserver agreement of three-dimensional contrast-enhanced ultrasound (3D-CEUS) volume calculations of focal liver lesions (FLLs). METHODS: Thirty-nine patients (15 men and 24 women; mean age, 55.4 years) with 39 FLLs (mean size, 3.1±1.8 cm; size range, 1 to 8 cm) prospectively underwent 3D-CEUS. Four readers calculated the volume of each lesion in an independent and blinded fashion in two separate sessions by means of a semi-automatic, commercially available proprietary software. The differences in lesion volumes (cm3) among sessions and readers were assessed using the Mann-Whitney U test and the Kruskal-Wallis test. Bland-Altman analysis was also performed. Intraclass correlation coefficients (ICCs) with 95% confidence intervals (95% CIs) were calculated. The statistical significance level was set at P<0.05. RESULTS: Among readers, there were no statistically significant differences in the first (P=0.953) and second (P=0.592) reading sessions for volume calculations of the 39 FLLs, with almost perfect inter-reader agreement (ICC values of the first reading session, 0.996; 95% CI, 0.992 to 0.998 and ICC value of the second reading session, 0.994; 95% CI, 0.990 to 0.997, respectively). For each of the four readers, there were no significant differences in volume calculations between the two sessions (P=0.503-0.924), and the intrareader agreement was almost perfect for each reader (R1: ICC, 0.995; 95% CI, 0.991 to 0.998; R2: ICC, 0.995; 95% CI, 0.988 to 0.997; R3: ICC, 0.996; 95% CI, 0.992 to 0.998; R4: ICC, 0.985; 95% CI, 0.971 to 0.992). CONCLUSION: 3D-CEUS volume calculations provided consistent measurements across different readers with almost perfect intrareader agreement.

Hepatocellular carcinoma with macrovascular invasion: multimodality imaging features for the diagnosis.

Hepatocellular carcinoma (HCC) is frequently associated with macrovascular invasion of the portal vein or hepatic veins in advanced stages. The accurate diagnosis of macrovascular invasion and the differentiation from bland non-tumoral thrombus has significant clinical and management implications, since it narrows the therapeutic options and it represents a mandatory contraindication for liver resection or transplantation. The imaging diagnosis remains particularly challenging since the imaging features of HCC with macrovascular invasion may be subtle, especially in lesions showing infiltrative appearance. However, each radiologic imaging modality may provide findings suggesting the presence of tumor thrombus rather than bland thrombus. The purpose of this paper is to review the current guidelines and imaging appearance of HCC with macrovascular invasion. Knowledge of the most common imaging features of HCC with macrovascular invasion may improve the diagnostic confidence of tumor thrombus in clinical practice and help to guide patients' management.

Uncommon imaging evolutions of focal liver lesions in cirrhosis.

OBJECTIVE: The purpose of this article is to describe and illustrate uncommon imaging evolutions of benign (i.e., cyst, hemangioma, focal nodular hyperplasia-like nodules, and hepatic angiomyolipoma) and malignant (i.e., HCC and non HCC malignancies) lesions in a cirrhotic liver. The content highlights relevant pathogenesis and imaging clues for proper differential diagnosis. Revision of prior imaging and knowledge of these scenarios may help the abdominal radiologist to reach a noninvasive diagnosis and direct the patient to the most appropriate clinical management. CONCLUSION: Uncommon imaging evolutions of focal liver lesions in cirrhosis may represent a challenge for the abdominal radiologist, with atypical changes in size, and internal vascularization changes that may lead to misdiagnoses.