Use of percutaneous imaging-guided biopsy for Liver Imaging and Reporting Data System (LI-RADS) observations: A retrospective study from two liver transplant centers

Since the adoption of guidelines for the non-invasive imaging diagnosis of hepatocellular carcinoma (HCC), the need for sampling of a lesion in cirrhosis has decreased. We aimed to retrospectively investigate the use of percutaneous imaging-guided biopsy for LI-RADS observations in cirrhosis in two large liver transplant centers. A review of the pathology database in the two Institutions (Institution A, Institution B) was conducted to identify patients that underwent percutaneous imaging-guided biopsy for a liver lesion in the interval time 01/01/2015-12/312020. Liver observations on pre-procedure contrast-enhanced CT or MRI were classified according to LI-RADS v2018. Among the 728 patients who underwent imaging guided biopsy of a liver lesion in Institution A, and among the 749 patients who underwent imaging guided biopsy of a liver lesion in Institution B, respectively 50 (6.8 %) and 16 (2.1 %) were cirrhotic with available pre-procedural contrast-enhanced CT or MRI. A total of 67 lesions were biopsied. 30/67 (45 %) biopsied observations were classified as LR-M. 55/67 (82 %) biopsies were positive for malignancy at histopathology and among them 33 (60 %) were HCC. In conclusion, a small percentage of percutaneous, imaging-guided biopsies for liver lesions are performed in cirrhosis, and more frequently for LR-M observations.

Enhancing Patient Communication With Chat-GPT in Radiology: Evaluating the Efficacy and Readability of Answers to Common Imaging-Related Questions

PURPOSE

To assess ChatGPT's accuracy, relevance, and readability in answering patients' common imaging-related questions and examine the effect of a simple prompt.

METHODS

A total of 22 imaging-related questions were developed from categories previously described as important to patients, as follows: safety, the radiology report, the procedure, preparation before imaging, meaning of terms, and medical staff. These questions were posed to ChatGPT with and without a short prompt instructing the model to provide an accurate and easy-to-understand response for the average person. Four board-certified radiologists evaluated the answers for accuracy, consistency, and relevance. Two patient advocates also reviewed responses for their utility for patients. Readability was assessed using the Flesch Kincaid Grade Level. Statistical comparisons were performed using χ2 and paired t tests.

RESULTS

A total of 264 answers were assessed for both unprompted and prompted questions. Unprompted responses were accurate 83% of the time (218 of 264), which did not significantly change for prompted responses (87% [229 of 264]; P = .2). The consistency of the responses increased from 72% (63 of 88) to 86% (76 of 88) when prompts were given (P = .02). Nearly all responses (99% [261 of 264]) were at least partially relevant for both question types. Fewer unprompted responses were considered fully relevant at 67% (176 of 264), although this increased significantly to 80% when prompts were given (210 of 264; P = .001). The average Flesch Kincaid Grade Level was high at 13.6 [CI, 12.9-14.2], unchanged with the prompt (13.0 [CI, 12.41-13.60], P = .2). None of the responses reached the eighth-grade readability level recommended for patient-facing materials.

DISCUSSION

ChatGPT demonstrates the potential to respond accurately, consistently, and relevantly to patients' imaging-related questions. However, imperfect accuracy and high complexity necessitate oversight before implementation. Prompts reduced response variability and yielded more-targeted information, but they did not improve readability. ChatGPT has the potential to increase accessibility to health information and streamline the production of patient-facing educational materials; however, its current limitations require cautious implementation and further research.

Development and validation of an image biomarker to identify metabolic dysfunction associated steatohepatitis: MR-MASH score

BACKGROUND AND AIMS

Diagnosis of metabolic dysfunction-associated steatohepatitis (MASH) requires histology. In this study, a magnetic resonance imaging (MRI) score was developed and validated to identify MASH in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). Secondarily, a screening strategy for MASH diagnosis was investigated.

METHODS

This prospective multicentre study included 317 patients with biopsy-proven MASLD and contemporaneous MRI. The discovery cohort (Spain, Portugal) included 194 patients. NAFLD activity score (NAS) and fibrosis were assessed with the NASH-CRN histologic system. MASH was defined by the presence of steatosis, lobular inflammation, and ballooning, with NAS ≥4 with or without fibrosis. An MRI-based composite biomarker of Proton Density Fat Fraction and waist circumference (MR-MASH score) was developed. Findings were afterwards validated in an independent cohort (United States, Spain) with different MRI protocols.

RESULTS

In the derivation cohort, 51% (n = 99) had MASH. The MR-MASH score identified MASH with an AUC = .88 (95% CI .83-.93) and strongly correlated with NAS (r = .69). The MRI score lower cut-off corresponded to 88% sensitivity with 86% NPV, while the upper cut-off corresponded to 92% specificity with 87% PPV. MR-MASH was validated with an AUC = .86 (95% CI .77-.92), 91% sensitivity (lower cut-off) and 87% specificity (upper cut-off). A two-step screening strategy with sequential MR-MASH examination performed in patients with indeterminate-high FIB-4 or transient elastography showed an 83-84% PPV to identify MASH. The AUC of MR-MASH was significantly higher than that of the FAST score (p < .001).

CONCLUSIONS

The MR-MASH score has clinical utility in the identification and management of patients with MASH at risk of progression.

Brain-body communication in metabolic control

A thorough understanding of the mechanisms controlling energy homeostasis is needed to prevent and treat metabolic morbidities. While the contribution of organs such as the liver, muscle, adipose tissue, and pancreas to the regulation of energy has received wide attention, less is known about the interplay with the nervous system. Here, we highlight the role of the nervous systems in regulating metabolism beyond the classic hypothalamic endocrine signaling models and discuss the contribution of circadian rhythms, higher brain regions, and sociodemographic variables in the energy equation. We infer that interdisciplinary approaches are key to conceptually advancing the current research frontier and devising innovative therapies to prevent and treat metabolic disease.

Combined SPT and FCS methods reveal a mechanism of RNAP II oversampling in cell nuclei

Gene expression orchestration is a key question in fundamental and applied research. Different models for transcription regulation were proposed, yet the dynamic regulation of RNA polymerase II (RNAP II) activity remains a matter of debate. To improve our knowledge of this topic, we investigated RNAP II motility in eukaryotic cells by combining single particle tracking (SPT) and fluorescence correlation spectroscopy (FCS) techniques, to take advantage of their different sensitivities in order to analyze together slow and fast molecular movements. Thanks to calibrated samples, we developed a benchmark for quantitative analysis of molecular dynamics, to eliminate the main potential instrumental biases. We applied this workflow to study the diffusion of RPB1, the catalytic subunit of RNAP II. By a cross-analysis of FCS and SPT, we could highlight different RPB1 motility states and identifyed a stationary state, a slow diffusion state, and two different modes of subdiffusion. Interestingly, our analysis also unveiled the oversampling by RPB1 of nuclear subdomains. Based on these data, we propose a novel model of spatio-temporal transcription regulation. Altogether, our results highlight the importance of combining microscopy approaches at different time scales to get a full insight into the real complexity of molecular kinetics in cells.

Imaging Findings in Cirrhotic Liver: Pearls and Pitfalls for Diagnosis of Focal Benign and Malignant Lesions

Cirrhosis is the end stage of chronic liver disease and causes architectural distortion and perfusional anomalies. It is a major risk factor for developing hepatocellular carcinoma (HCC). Common disease entities in noncirrhotic livers, such as hemangiomas, can be rare in cirrhotic livers, and benign entities such as confluent hepatic fibrosis and focal nodular hyperplasia-like lesions may mimic the appearance of malignancies,. HCC usually has typical imaging characteristics, such as the major features established by the Liver Imaging Reporting and Data System. However, HCC can also have a spectrum of atypical or uncommon appearances, such as cystic HCC, hypovascular HCC, or macroscopic fat-containing HCC. HCCs with certain genetic mutations such as CTNNB-1-mutated HCC can harbor unique imaging features not seen in other types of HCC. In addition, malignancies that are less common than HCC, such as cholangiocarcinoma and metastases, which can be difficult to differentiate, can still occur in cirrhotic livers. Atypical imaging features of benign and malignant lesions can be challenging to accurately diagnose. Therefore, familiarity with these features and an understanding of the prevalence of disease entities in cirrhotic livers are key in the daily practice of radiologists for evaluation of cirrhotic livers. The authors illustrate the typical and atypical features of benign and malignant lesions in cirrhosis and discuss the technical pitfalls and unique advantages associated with various imaging modalities in assessing cirrhotic livers, including noncontrast and contrast-enhanced US, CT, and MRI. Work of the U.S. Government published under an exclusive license with the RSNA. Quiz questions for this article are available in the supplemental material.

Immediate and Late Complications After Liver Transplantation

Other than rejection, hepatic artery and portal vein thrombosis are the most common complications in the immediate postoperative period with hepatic arterial thrombosis more common and more devastating. Hepatic artery stenosis is more common 1 month after transplantation, whereas portal and hepatic vein stenosis is more often seen as a late complication. Ultrasound is the first-line imaging examination to diagnose vascular complications with contrast-enhanced CT useful if ultrasound findings are equivocal. MR cholangiography is often most helpful in diagnosing bile leaks, biliary strictures, and biliary stones.

Changes in thyroid nodule cytology rates after institutional implementation of the Thyroid Imaging Reporting and Data System

BACKGROUND

The American College of Radiology Thyroid Imaging Reporting and Data System for ultrasound classification of malignancy risk was developed to better triage thyroid nodules for fine-needle aspiration biopsy. To examine further, we compared thyroid cytologic classification rates in nodules before and after institutional Thyroid Imaging Reporting and Data System implementation.

METHODS

Cytology diagnoses by Bethesda criteria (categories I-VI) from January 2014 to October 2021 were retrieved; observed changes in yearly category frequency were analyzed by linear regression; and pooled cohorts of pre- (2014-2018) and post-Thyroid Imaging Reporting and Data System (2019-2021) cytology call rates were compared.

RESULTS

Overall, 7,413 cytologic specimens were included (range/year 715-1,444). From 2014 to 2021, the proportion of benign (Bethesda category II) diagnosis per year declined stepwise from 49.7% to 19.4%, and atypia of undetermined significance/follicular lesion of undetermined significance (Bethesda category III) increased sequentially from 21.3% to 51.5%. Between 2014 and 2021, Bethesda category III diagnosis increased on average by 4.8% per year (95% confidence internal, 3.29-5.54; P < .001) and Bethesda category II results decreased on average by 4.4% per year (95% confidence interval, 6.29-3.42; P < .001). When comparing pre- and post-Thyroid Imaging Reporting and Data System, the proportion of Bethesda category II cytology results decreased (43.1% vs 21%; P = .001) while Bethesda category III (28.3% vs 47.7%; P = .002) and Bethesda category V (1.1% vs 1.7%; P = .015) results increased.

CONCLUSION

After implementation of American College of Radiology Thyroid Imaging Reporting and Data System ultrasound criteria, we observed a 2.5-fold decline in the rate of benign cytology and an increase in the proportion of atypia of undetermined significance/follicular lesion of undetermined significance results.

Neurotensin neurons in the extended amygdala control dietary choice and energy homeostasis

Obesity is a global pandemic that is causally linked to many life-threatening diseases. Apart from some rare genetic conditions, the biological drivers of overeating and reduced activity are unclear. Here, we show that neurotensin-expressing neurons in the mouse interstitial nucleus of the posterior limb of the anterior commissure (IPAC), a nucleus of the central extended amygdala, encode dietary preference for unhealthy energy-dense foods. Optogenetic activation of IPAC^Nts neurons promotes obesogenic behaviors, such as hedonic eating, and modulates food preference. Conversely, acute inhibition of IPAC^Nts neurons reduces feeding and decreases hedonic eating. Chronic inactivation of IPAC^Nts neurons recapitulates these effects, reduces preference for sweet, non-caloric tastants and, furthermore, enhances locomotion and energy expenditure; as a result, mice display long-term weight loss and improved metabolic health and are protected from obesity. Thus, the activity of a single neuronal population bidirectionally regulates energy homeostasis. Our findings could lead to new therapeutic strategies to prevent and treat obesity.

Characterization of hepatic steatosis using controlled attenuation parameter and MRI-derived proton density fat fraction in living donor liver transplantation

BACKGROUND

The increasingly favorable outcomes of live donor liver transplant warrant development of screening techniques to expand current donor pool. Transient elastography (TE) with controlled attenuation parameter (CAP) is accessible and has promising diagnostic performance in non-obese individuals. Here, we demonstrate its utility in grading donor steatosis for risk assessment in living liver donors (LLD).

STUDY DESIGN

In a prospective study of LLD and recipients, accuracy was determined using MRI-derived proton density fat fraction (PDFF) as reference.

RESULTS

One hundred and one LLD underwent TE, 95 of whom had available PDFF. Median CAP and MRI-PDFF were 233 dB/m (206-270) and 2.9% (2.3-4.0), respectively. A CAP threshold of 270 dB/m captured all steatosis which was present in 13 (13%) LLD (AUROC .942, 100% sensitivity and 83% specificity). Performance further improved when excluding obese LLD and limiting analysis to M-probe (AUROC .971 and .974, respectively, with 87% specificity). There was no difference in CAP and MRI-PDFF between LLD and nondonors (P = .26 and .21, respectively). Early allograft dysfunction was observed in one recipient (CAP 316, PDFF 9.5%), zero underwent retransplant, and one died from sepsis.

CONCLUSION

The specific role of CAP in living liver donation warrants further study, beginning with its use as screening tool across peripheral clinics.

A Bloody Conspiracy. Blood Vessels and Immune Cells in the Tumor Microenvironment

Simple Summary

The tumor microenvironment has risen over the last years as a significant contributor to the failure of antitumoral strategies due to its numerous pro-tumorigenic activities. In this review, we focused on two features of this microenvironment, namely angiogenesis and immunity, which have been the targets of therapies to tackle tumors via its microenvironmental part over the last decade. Increasing our knowledge of the complex interactions within this ecosystem is mandatory to optimize these therapeutic approaches. The development of innovative experimental models is of great help in reaching this goal.

Abstract

Cancer progression occurs in concomitance with a profound remodeling of the cellular microenvironment. Far from being a mere passive event, the re-orchestration of interactions between the various cell types surrounding tumors highly contributes to the progression of the latter. Tumors notably recruit and stimulate the sprouting of new blood vessels through a process called neo-angiogenesis. Beyond helping the tumor cope with an increased metabolic demand associated with rapid growth, this also controls the metastatic dissemination of cancer cells and the infiltration of immune cells in the tumor microenvironment. To decipher this critical interplay for the clinical progression of tumors, the research community has developed several valuable models in the last decades. This review offers an overview of the various instrumental solutions currently available, including microfluidic chips, co-culture models, and the recent rise of organoids. We highlight the advantages of each technique and the specific questions they can address to better understand the tumor immuno-angiogenic ecosystem. Finally, we discuss this development field’s fundamental and applied perspectives.

An Overview of the Circadian Clock in the Frame of Chronotherapy: From Bench to Bedside

Most living organisms in both the plant and animal kingdoms have evolved processes to stay in tune with the alternation of day and night, and to optimize their physiology as a function of light supply. In mammals, a circadian clock relying on feedback loops between key transcription factors will thus control the temporally regulated pattern of expression of most genes. Modern ways of life have highly altered the synchronization of human activities with their circadian clocks. This review discusses the links between an altered circadian clock and the rise of pathologies. We then sum up the proofs of concept advocating for the integration of circadian clock considerations in chronotherapy for health care, medicine, and pharmacotherapy. Finally, we discuss the current challenges that circadian biology must face and the tools to address them.

Abstract 1671: Engineering new cellular models to decipher H3.3K27M mutation role in DIPGs' resistance to therapies

Among pediatric brain tumors, Diffuse Intrinsic Pontine Gliomas (DIPGs) display a particularly dismal prognosis, highlighted by their median survival lower than one year. Indeed, DIPGs’ location and infiltrative properties preclude their surgical resection. Moreover, DIPGs poorly respond to chemotherapeutic agents. In this context, the only treatment for these tumors remains palliative radiotherapy, systematically followed by tumor progression. In addition to their resistance to therapies, DIPGs are characterized by recurrent histone H3 mutations. The H3.3K27M mutation is the most frequent and results from a heterozygous single nucleotide variant in the H3F3A gene, inducing the lysine 27 substitution by a methionine. Although H3.3K27M’s driver role in DIPGs tumorigenesis is now established, its role in their chemo- and radioresistance remains unclear. Aiming to decipher the potential role of this mutation in pediatric gliomas’ resistance to therapies, we established isogenic cellular models of H3.3K27M induction and reversion.We first induced H3.3K27M mutation in three initially non-mutated supratentorial pediatric glioma cell lines. Thus, we generated models that stably expressed the dominant-negative H3.3K27M or the wild type H3.3 as controls. Complementarily, to study H3.3K27M roles in a DIPG cell context, we also developed H3.3K27M reversion models in two initially mutated DIPG cell lines by applying a gene-editing strategy based on the combinatorial use of the CRISPR/Cas9 technology and an insert.We showed that H3.3K27M induction in Res259 and KNS42 cells conferred a radioresistant phenotype to a fractionated radiotherapy schedule. Besides, we performed a screening of 80 anti-cancer drugs, which revealed a differential impact of the mutation on the drug sensitivity profiles of our three H3.3K27M-induced cell lines. These results indicate that H3.3K27M can control pediatric glioma cells’ resistance to therapies, but in a heterogeneous way depending on the cellular context. Along this line, we are currently characterizing the chemo- and radiotherapy response of our new DIPG H3.3K27M-reversed models. Altogether, our first results support a role for H3.3K27M in pediatric gliomas resistance to treatments, and our complementary models pave the way for identifying new H3.3K27M-dependent mechanisms and promising targets to sensitize DIPGs to therapies.

Citation Format: Andria Rakotomalala, Paul Lewandowski, Quentin Bailleul, Clara Savary, Mélanie Arcicasa, Christine Bal, Maud Hamadou, Paul Huchedé, Audrey Restouin, Remy Castellano, Yves Collette, Audrey Vincent, Pierre-Olivier Angrand, Eric Adriaenssens, Xuefen Le Bourhis, Pierre Leblond, Marie Castets, Eddy Pasquier, Alessandro Furlan, Samuel Meignan. Engineering new cellular models to decipher H3.3K27M mutation role in DIPGs' resistance to therapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1671.

Deep Learning Prediction of Voxel-Level Liver Stiffness in Patients with Nonalcoholic Fatty Liver Disease

Purpose

To reconstruct virtual MR elastography (MRE) images based on traditional MRI inputs with a machine learning algorithm.

Materials and Methods

In this single-institution, retrospective study, 149 patients (mean age, 58 years ± 12 [standard deviation]; 71 men) with nonalcoholic fatty liver disease who underwent MRI and MRE between January 2016 and January 2019 were evaluated. Nine conventional MRI sequences and clinical data were used to train a convolutional neural network to reconstruct MRE images at the per-voxel level. The architecture was further modified to accept multichannel three-dimensional inputs and to allow inclusion of clinical and demographic information. Liver stiffness and fibrosis category (F0 [no fibrosis] to F4 [significant fibrosis]) of reconstructed images were assessed by using voxel- and patient-level agreement by correlation, sensitivity, and specificity calculations; in addition, classification by receiver operator characteristic analyses was performed, and Dice score was used to evaluate hepatic stiffness locality.

Results

The model for predicting liver stiffness incorporated four image sequences (precontrast T1-weighted liver acquisition with volume acquisition [LAVA] water and LAVA fat, 120-second-delay T1-weighted LAVA water, and single-shot fast spin-echo T2 weighted) and clinical data. The model had a patient-level and voxel-level correlation of 0.50 ± 0.05 and 0.34 ± 0.03, respectively. By using a stiffness threshold of 3.54 kPa to make a binary classification into no fibrosis or mild fibrosis (F0-F1) versus clinically significant fibrosis (F2-F4), the model had sensitivity of 80% ± 4, specificity of 75% ± 5, accuracy of 78% ± 3, area under the receiver operating characteristic curve of 84 ± 0.04, and a Dice score of 0.74.

Conclusion

The generation of virtual elastography images is feasible by using conventional MRI and clinical data with a machine learning algorithm.Keywords: MR Imaging, Abdomen/GI, Liver, Cirrhosis, Computer Applications/Virtual Imaging, Experimental Investigations, Feature Detection, Classification, Reconstruction Algorithms, Supervised Learning, Convolutional Neural Network (CNN) Supplemental material is available for this article. © RSNA, 2021.

Tumor in vein (LR-TIV) and liver imaging reporting and data system (LI-RADS) v2018: diagnostic features, pitfalls, prognostic and management implications

Vascular invasion by hepatocellular carcinoma (HCC), also known as tumor in vein (TIV), indicates highly invasive tumor behavior and is also associated with poor outcome. Because a diagnosis of TIV precludes liver transplantation, knowledge of the imaging findings to differentiate between TIV and bland thrombus is key for proper patient management. Prior versions of liver imaging reporting and data system (LI-RADS) included presence of TIV as part of LR-5 criteria. However, even if HCC is the most common liver malignancy associated with TIV, other tumors can have vascular invasion and may occur in cirrhotic patients. For these reasons, in LI-RADS v2017 LR-TIV has been introduced as a new different diagnostic category. The aim of this article is to discuss the diagnostic criteria of LR-TIV according to LI-RADS v2018 and analyze potential pitfalls encountered on daily clinical practice. Indeterminate cases and how to manage them will also be discussed.

Imaging Evaluation of Living Liver Donor Candidates: Techniques, Protocols, and Anatomy

The need for liver transplants is increasing because the prevalence of liver diseases and the indications for transplants are growing. In response to the shortage of grafts from deceased donors, more transplants are being performed worldwide with grafts from living donors. Radiologic evaluation is an integral component in the assessment of donor candidates to ensure their eligibility and to choose the most appropriate surgical approach. MRI is the preferred modality for evaluation of the liver parenchyma and biliary tree. In most centers, a combination of MRI and CT is used to take advantage of the higher spatial resolution of CT for evaluation of arteries. However, MRI-only assessment is feasible. In addition to assessment of the liver parenchyma for abnormalities such as steatosis, a detailed evaluation of the hepatic vascular and biliary system for pertinent anatomic variants is crucial, because these variants can affect surgical techniques and outcomes in both recipients and donors. In this pictorial article, after a brief review of the most common surgical techniques and postsurgical liver anatomy, the biliary and vascular anatomy are discussed, with specific attention paid to the variants that are pertinent to this surgical procedure. The roles of liver segmentation and volumetric assessment and current imaging techniques and protocols are also discussed. Online supplemental material is available for this article. ©RSNA, 2021.

Molecular architecture of the developing mouse brain

The mammalian brain develops through a complex interplay of spatial cues generated by diffusible morphogens, cell-cell interactions and intrinsic genetic programs that result in probably more than a thousand distinct cell types. A complete understanding of this process requires a systematic characterization of cell states over the entire spatiotemporal range of brain development. The ability of single-cell RNA sequencing and spatial transcriptomics to reveal the molecular heterogeneity of complex tissues has therefore been particularly powerful in the nervous system. Previous studies have explored development in specific brain regions^1-8, the whole adult brain⁹ and even entire embryos¹⁰. Here we report a comprehensive single-cell transcriptomic atlas of the embryonic mouse brain between gastrulation and birth. We identified almost eight hundred cellular states that describe a developmental program for the functional elements of the brain and its enclosing membranes, including the early neuroepithelium, region-specific secondary organizers, and both neurogenic and gliogenic progenitors. We also used in situ mRNA sequencing to map the spatial expression patterns of key developmental genes. Integrating the in situ data with our single-cell clusters revealed the precise spatial organization of neural progenitors during the patterning of the nervous system.

Evaluation of clinical and imaging biomarkers for the prediction of new onset diabetes following pancreatic resection

PURPOSE

To identify clinical and imaging biomarkers that can predict the new onset of diabetes mellitus (NODM) within 1 year of pancreatic resection.

METHODS

A retrospective chart review was conducted of 426 non-diabetic patients who underwent a pancreaticoduodenectomy or distal pancreatectomy at the University of Pittsburgh Medical Center between 2006 and 2016. Clinical characteristics and the patient's diabetic status at 1-year post resection were collected from the EMR. Imaging biomarkers included hepatic and pancreatic fat replacement, pancreatic calcifications, pancreatic duct diameter, pancreatic volume and body composition. Univariate and multivariable analyses were performed to demonstrate any predictive biomarkers of diabetes occurrence within 1 year of pancreatic resection.

RESULTS

135/426 (31.7%) patients developed NODM. The only significant clinical predictor was older age (OR 1.02, 95% CI 1.002-1.039, p = 0.032). Imaging characteristics found to be significant included hepatic steatosis (OR 1.777, 95% CI 1.094-2.886, p = 0.02), larger reduction in pancreas volume (OR 0.989, 95% CI 0.979-0.999, p = 0.027), and greater preoperative visceral fat (OR 1.004, 95% CI 1.001-1.006, p = 0.001).

CONCLUSION

Age, presence of hepatic steatosis, change in pancreatic volume, and preoperative visceral fat are independent predictive biomarkers for NODM following pancreatic resection.

Magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) is a viable alternative to liver biopsy for steatosis quantification in living liver donor transplantation

This study aimed to investigate whether magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) can be a viable noninvasive alternative to liver biopsy for the quantification of living liver donor steatosis. Hepatic steatosis for 143 donors was graded by MRI-PDFF. Study endpoints included liver volume regeneration in donors, recipient outcomes including length of hospital stay, deaths, primary non-function (PNF), early allograft dysfunction (EAD), and small for size syndrome (SFSS). Correlation between MRI-PDFF determined donor steatosis and endpoints were analyzed. Donors had lower steatosis grade than non-donors. Donor remnant liver regenerated to an average of 82% of pre-donation volume by 101 ± 24 days with no complications. There was no correlation between percent liver regeneration and steatosis severity. Among recipients, 4 underwent redo-transplantation and 6 died, with no association with degree of steatosis. 52 recipients (36%) fulfilled criteria for EAD (driven by INR), with no difference in hepatic steatosis between groups. MRI-PDFF reliably predicted donor outcomes. Living donors with no or mild steatosis based on MRI-PDFF (ie, <20%) and meeting other criteria for donation can expect favorable post-surgical outcomes, including liver regeneration. Recipients had a low rate of death or retransplantation with no association between mild hepatic steatosis and EAD.

Improved survival following transarterial radioembolization of infiltrative-appearance hepatocellular carcinoma

PURPOSE

Infiltrative-appearance hepatocellular carcinoma presents a challenge to clinicians as diagnostic criteria continue to evolve and evidence-based treatment guidelines have yet to be established. While transarterial radioembolization has shown efficacy in hepatocellular carcinoma, many studies exclude infiltrative-appearance HCC in their analysis. The purpose of this study was to describe imaging features of infiltrative-appearance hepatocellular carcinoma and evaluate effects of radioembolization on survival.

METHODS

In a retrospective review, infiltrative HCC patients treated from 2008 to 2017 were identified. Patients were divided into two groups: TARE versus systemic therapy/palliative care. Demographics, dates of diagnosis/expiry, albumin, international normalized ratio (INR), sodium, alpha-fetoprotein (AFP), creatinine, Child-Pugh class, model for end-stage liver disease (MELD) score, bilirubin, radiation dose and volume were collected. Patients with bilirubin > 3 were excluded. Mann-Whitney U test and Fisher's exact test assessed differences between groups. Kaplan-Meier survival and Cox proportional hazard analyses were performed.

RESULTS

Fifty-three patients were identified, 15 underwent TARE while 38 served as control. Mean age was 60, 43 patients were male. The mean overall survival was 16.2 months for the TARE group and 5.3 months for the control group (Log-rank p < 0.0001). Cox proportional regression analysis revealed significant associations between survival and albumin (HR 0.210, 0.052-0.839, p = 0.027), Child-Pugh class B (HR 0.196, 0.055-0.696, p = 0.012), sorafenib (HR 0.106, 0.031-0.360, p < 0.001), and number of affected liver lobes (HR 1.864, 1.387-2.506, p < 0.001).

CONCLUSIONS

Transarterial radioembolization for infiltrative HCC improves life expectancy compared to treatment with comfort measures or systemic therapy.

Performance of morphologic criteria for the diagnosis of cirrhosis in patients with non-alcoholic steatohepatitis compared to other etiologies of chronic liver disease: effect of level of training and experience

PURPOSE

To compare the diagnostic performance of morphologic criteria for detection of cirrhosis in patients with alcoholic liver disease (ALD), hepatitis C (HCV), and non-alcoholic steatohepatitis (NASH).

METHODS

One hundred patients (53 male) with different etiologies of chronic liver disease (NASH, n = 41; HCV, n = 39; and ALD, n = 20) and with different degrees of fibrosis on histopathologic examination (74 with cirrhosis) were retrospectively evaluated. Four readers (R1: fellowship-trained abdominal radiologist, R2: community attending radiologist, R3: senior radiology resident/research fellow, R4: junior radiology resident) analyzed the contrast-enhanced CTs for presence of commonly accepted morphologic changes of cirrhosis and portal hypertension. Each reader assigned an overall score (using a 5-point scale) for possibility of cirrhosis based on liver morphology and features of portal hypertension. Diagnostic performance, sensitivity, and specificity for the diagnosis of cirrhosis were calculated and compared between different etiologies of chronic liver disease.

RESULTS

Performance of readers was affected by their level of training. Less experienced readers had overall lower sensitivity for diagnosis of cirrhosis in NASH group (R3: 81.5%, R4: 63.0% compared to 96.3% for both R1 and R2). Sensitivities for detection of NASH cirrhosis significantly decreased for less experienced readers in the absence of ascites (R3: 75.0%, R4: 62.0%) or other features of portal hypertension (R3: 50.0%; R4: 0%). The specificity was consistently high among different etiologies and for all readers (85.7-100%). Inter-reader agreement for morphologic features ranged widely from fair to almost perfect (k: 0.23-0.85).

CONCLUSION

Cirrhotic changes in NASH are subtler and can be underestimated by less experienced readers.

[The art of war as applied to pediatric gliomas: Know your enemy]

Pediatric brain cancers represent the most frequent solid tumors and the leading cause of cancer-driven mortality in children. Pediatric High Grade Gliomas display a very poor prognosis. Among these, DIPG (Diffuse Intrinsic Pontine Gliomas), localized to the brain stem, cannot benefit from a total exeresis due to this critical location and to their highly infiltrating nature. Radiotherapy remains the standard treatment against these tumors for almost five decades, and attempts to improve the prognosis of patients with chemotherapy or targeted therapies have failed. Thanks to the rise of high throughput sequencing, the knowledge of molecular alterations in pediatric gliomas strongly progressed and allowed to highlight distinct biomolecular entities and to establish more accurate diagnoses. In this review, we summarize this new information and the perspectives that it brings for clinical strategies.

Online Liver Imaging Course; Pivoting to Transform Radiology Education During the SARS-CoV-2 Pandemic

PURPOSE

The SARS-CoV-2 pandemic has drastically disrupted radiology in-person education. The purpose of this study was to assess the implementation of a virtual teaching method using available technology and its role in the continuity of education of practicing radiologists and trainees during the pandemic.

METHODS

The authors created the Online Liver Imaging Course (OLIC) that comprised 28 online comprehensive lectures delivered in real-time and on-demand over six weeks. Radiologists and radiology trainees were asked to register to attend the live sessions. At the end of the course, we conducted a 46-question survey among registrants addressing their training level, perception of virtual conferencing, and evaluation of the course content.

RESULTS

One thousand four hundred and thirty four radiologists and trainees completed interest sign up forms before the start of the course with the first webinar having the highest number of live attendees (343 people). On average, there were 89 live participants per session and 750 YouTube views per recording (as of July 9, 2020). After the end of the course, 487 attendees from 37 countries responded to the postcourse survey for an overall response rate of (33%). Approximately (63%) of participants were practicing radiologists while (37%) were either fellows or residents and rarely medical students. The overwhelming majority (97%) found the OLIC webinar series to be beneficial. Essentially all attendees felt that the webinar sessions met (43%) or exceeded (57%) their expectations. When asked about their perception of virtual conferences after attending OLIC lectures, almost all attendees (99%) enjoyed the virtual conference with a majority (61%) of the respondents who enjoyed the virtual format more than in-person conferences, while (38%) enjoyed the webinar format but preferred in-person conferences. When asked about the willingness to attend virtual webinars in the future, (84%) said that they would attend future virtual conferences even if in-person conferences resume while (15%) were unsure.

CONCLUSION

The success of the OLIC, attributed to many factors, indicates that videoconferencing technology provides an inexpensive alternative to in-person radiology conferences. The positive responses to our postcourse survey suggest that virtual education will remain to stay. Educational institutions and scientific societies should foster such models.

Hypoxia in Solid Tumors: How Low Oxygenation Impacts the "Six Rs" of Radiotherapy

Radiotherapy is an important component of cancer treatment, with approximately 50% of all cancer patients receiving radiation therapy during their course of illness. Nevertheless, solid tumors frequently exhibit hypoxic areas, which can hinder therapies efficacy, especially radiotherapy one. Indeed, hypoxia impacts the six parameters governing the radiotherapy response, called the « six Rs of radiation biology » (for Radiosensitivity, Repair, Repopulation, Redistribution, Reoxygenation, and Reactivation of anti-tumor immune response), by inducing pleiotropic cellular adaptions, such as cell metabolism rewiring, epigenetic landscape remodeling, and cell death weakening, with significant clinical repercussions. In this review, according to the six Rs, we detail how hypoxia, and associated mechanisms and pathways, impact the radiotherapy response of solid tumors and the resulting clinical implications. We finally illustrate it in hypoxic endocrine cancers through a focus on anaplastic thyroid carcinomas.

Texture analysis on preoperative contrast-enhanced magnetic resonance imaging identifies microvascular invasion in hepatocellular carcinoma

BACKGROUND

Radiomic texture analysis quantifies tumor heterogeneity. The aim of this study is to determine if radiomics can predict biologic aggressiveness in HCC and identify tumors with MVI.

METHODS

Single-center, retrospective review of HCC patients undergoing resection/ablation with curative intent from 2009 to 2017. DICOM images from preoperative MRIs were analyzed with texture analysis software. Texture analysis parameters extracted on T1, T2, hepatic arterial phase (HAP) and portal venous phase (PVP) images. Multivariate logistic regression analysis evaluated factors associated with MVI.

RESULTS

MVI was present in 52.2% (n = 133) of HCCs. On multivariate analysis only T1 mean (OR = 0.97, 95%CI 0.95-0.99, p = 0.043) and PVP entropy (OR = 4.7, 95%CI 1.37-16.3, p = 0.014) were associated with tumor MVI. Area under ROC curve was 0.83 for this final model. Empirical optimal cutpoint for PVP tumor entropy and T1 tumor mean were 5.73 and 23.41, respectively. At these cutpoint values, sensitivity was 0.68 and 0.5, respectively and specificity was 0.64 and 0.86. When both criteria were met, the probability of MVI in the tumor was 87%.

CONCLUSION

Tumor entropy and mean are both associated with MVI. Texture analysis on preoperative imaging correlates with microscopic features of HCC and can be used to predict patients with high-risk tumors.

Diagnostic Value of FDG PET/MRI in Females With Pelvic Malignancy-A Systematic Review of the Literature

Hybrid imaging with F-18 fludeoxyglucose positron emission tomography/magnetic resonance imaging (FDG PET/MRI) has increasing clinical applications supplementing conventional ultrasound, CT, and MRI imaging as well as hybrid PET/CT imaging in assessing cervical, endometrial, and ovarian cancer. This article summarizes the existing literature and discusses the emerging role of hybrid PET/MRI in gynecologic malignancies. Thus, far, the published literature on the applications of FDG PET/MRI shows that it can have a significant impact on patient management by improving the staging of the cancers compared with PET/CT, influencing clinical decision and treatment strategy. For disease restaging, current literature indicates that PET/MRI performs equivalently to PET/CT. There appears to be a mild-moderate inverse correlation between standard-uptake-value (SUV) and apparent-diffusion-coefficient (ADC) values, which could be used to predict tumor grading and risk stratification. It remains to be seen as to whether multi-parametric PET/MRI imaging could prove valuable for prognostication and outcome. PET/MRI provides the opportunity for reduced radiation exposure, which is particularly relevant for a young female in need of multiple scans for treatment monitoring and follow-up. Fast acquisition protocols and optimized methods for attenuation correction are still evolving. Major limitations of PET/MRI remains such as suboptimal detection of small pulmonary nodules and lack of utility for radiation treatment planning, which pose an impediment in making PET/MRI a viable one-stop-shop imaging option to compete with PET/CT.

68Ga-DOTATATE PET/MRI for Neuroendocrine Tumors: A Pictorial Review

Neuroendocrine tumors (NETs) constitute a variety of neoplastic entities and exhibit variable degrees of neuroendocrine differentiation and phenotypes, as well as genetic profiles. Ga-DOTATATE PET is a novel imaging technique for NET. Although PET/CT is commonly utilized for oncologic imaging, PET/MRI is particularly suited for NETs, as MRI provides greater soft tissue contrast than CT, allowing for improved detection and characterization of NETs, particularly when liver metastasis is suspected or needs to be ruled out. The current pictorial review aims to illustrate the complementary advantages, as well as pitfalls of Ga-DOTATATE PET/MRI in the evaluation of NETs.

Day and blue light modify growth, cell physiology and indole-3-acetic acid production of Azospirillum brasilense Az39 under planktonic growth conditions

AIM

In this work, we evaluated the effects of light on growth, cell physiology and stress response of Azospirillum brasilense Az39, a non-photosynthetic rhizobacteria, under planktonic growth conditions.

METHODS AND RESULTS

Exponential cultures of Az39 were exposed to blue (BL), red (RL) and daylight (DL) or maintained in darkness for 24, 48 and 72 h. The biomass production and indole 3-acetic acid (IAA) biosynthesis increased by exposition to DL. Conversely, BL decreased IAA concentration through a direct effect on the molecule. The DL increased superoxide dismutase activity, hydrogen peroxide and thiobarbituric acid reactive substances levels, but the last one was also increased by BL. Both DL and BL increased cell aggregation but only BL increased biofilm formation.

CONCLUSIONS

We demonstrated that both BL and DL are stress effectors for A. brasilense Az39 under planktonic growth conditions. The DL increased biomass production, IAA biosynthesis and bacterial response to stress, whereas BL induced cell aggregation and biofilms formation, but decreased the IAA concentration by photooxidation.

SIGNIFICANCE AND IMPACT OF THE STUDY

Blue light and DL changes growth capacity, cell physiology and plant growth promotion ability of A. brasilense Az39 and these changes could be considered to improve the production and functionality of biofertilizers.

A Genetically Defined Compartmentalized Striatal Direct Pathway for Negative Reinforcement

The striosome compartment within the dorsal striatum has been implicated in reinforcement learning and regulation of motivation, but how striosomal neurons contribute to these functions remains elusive. Here, we show that a genetically identified striosomal population, which expresses the Teashirt family zinc finger 1 (Tshz1) and belongs to the direct pathway, drives negative reinforcement and is essential for aversive learning in mice. Contrasting a "conventional" striosomal direct pathway, the Tshz1 neurons cause aversion, movement suppression, and negative reinforcement once activated, and they receive a distinct set of synaptic inputs. These neurons are predominantly excited by punishment rather than reward and represent the anticipation of punishment or the motivation for avoidance. Furthermore, inhibiting these neurons impairs punishment-based learning without affecting reward learning or movement. These results establish a major role of striosomal neurons in behaviors reinforced by punishment and moreover uncover functions of the direct pathway unaccounted for in classic models.

Diagnostic value of MRI-derived liver surface nodularity score for the non-invasive quantification of hepatic fibrosis in non-alcoholic fatty liver disease

OBJECTIVES

To assess the accuracy of MRI-derived liver surface nodularity (LSN) score for staging of hepatic fibrosis in patients with non-alcoholic fatty liver disease (NAFLD).

METHODS

Forty-seven patients with clinicopathological diagnosis of NAFLD who underwent 1.5-T liver MRI within 12 months of liver biopsy were included. Axial non-contrast T1-weighted 3D GRE was used for image analysis. LSN of the left lobe was measured using a custom semiautomated software. Histopathologic analysis (F0-F4) served as the reference standard for staging of fibrosis. Mann-Whitney test and Spearman's correlation coefficient were used to compare LSN scores between different stages of fibrosis and to assess the correlation. Diagnostic performance of LSN score for detection of significant (F2-F4) and advanced (F3-F4) fibrosis was assessed by receiver operating characteristics (ROC) curve. p value of less than 0.05 was considered statistically significant different.

RESULTS

Twenty-one subjects had advanced fibrosis. The LSN scores among different stages of fibrosis were significantly different (p < 0.001). The correlation between LSN score and stage of fibrosis was also strong (ρ = 0.71; p < 0.001). The areas under ROC curves for detection of significant and advanced fibrosis were 0.80 (95% CI 0.66-0.95) and 0.86 (95% CI 0.75-0.97), using a threshold of 2.23 and 2.44, respectively. This method showed 81% sensitivity and 88% specificity for detection of advanced fibrosis.

CONCLUSION

MR-based LSN score is a promising non-invasive objective tool for detection of advanced fibrosis in patients with NAFLD.

KEY POINTS

• Liver surface nodularity (LSN) score is a fast retrospective method for precise quantification of nodularity of liver surface. • MR-based LSN score is a promising non-invasive objective tool to accurately detect different stages of fibrosis in patients with non-alcoholic fatty liver disease (NAFLD).

Hepatic enhancement in cirrhosis in the portal venous phase: what are the differences between gadoxetate disodium and gadobenate dimeglumine?

PURPOSE

To compare the level of parenchymal and portal venous enhancement in the portal venous phase (PVP) in cirrhotic patients undergoing gadoxetate disodium- and gadobenate dimeglumine-enhanced MRI.

METHODS

In this retrospective study, 84 cirrhotic patients (mean age ± SD: 66 ± 13 years) who underwent contrast-enhanced MRI with both gadoxetate disodium and gadobenate dimeglumine between 2012 and 2018 were included. Two readers measured signal intensities of hepatic parenchyma, portal vein and psoas muscle on precontrast and PVP. Relative enhancement (RE), image contrast, and portal vein-to-liver contrast difference were calculated. Intraindividual differences were compared with the Wilcoxon signed rank-sum test and inter-reader differences with the intraclass correlation coefficient (ICC).

RESULTS

In PVP, gadoxetate disodium provided lower RE than gadobenate dimeglumine (Reader 1: 42.4 ± 44.6 vs. 56.1 ± 58.8, p = 0.044; Reader 2: 42.4 ± 42.9 vs. 57.7 ± 60.5, p = 0.027;), lower image contrast (Reader 1: 0.27 ± 0.11 vs. 0.35 ± 0.11, respectively; p < 0.001; Reader 2: 0.29 ± 0.10 vs. 0.37 ± 0.07, respectively; p < 0.001), and lower portal vein-to-liver contrast difference (Reader 1: 0.89 ± 0.39 vs. 1.42 ± 0.90, p < 0.001; Reader 2: 0.95 ± 0.40 vs. 1.28 ± 0.37, p < 0.001). ICC was 0.94, 0.79, and 0.69 for RE, image contrast, and portal vein-to-liver contrast difference, respectively.

CONCLUSION

In cirrhotic patients, gadoxetate disodium yielded lower enhancement of the hepatic parenchyma and lower contrast of the portal vein than gadobenate dimeglumine in PVP.

18F-FDG PET/MRI Primary Staging of Cervical Cancer: A Pilot Study with PET/CT Comparison

We report our PET/MRI experience from a pilot study that compared the diagnostic performance of ¹⁸F-FDG PET/MRI versus PET/CT in staging of cervical cancer. Methods: Six adults with newly diagnosed cervical cancer underwent a single ¹⁸F-FDG injection with a dual-imaging protocol: standard-of-care PET/CT followed by research PET/MRI. The diagnostic interpretation and SUV_max for the 2 modalities were compared. Results: Both modalities detected all primary tumors (median size, 3.9 cm) and all 4 metastases present in 2 of the 6 patients (median size, 0.9 cm). PET/MRI provided greater diagnostic confidence than PET/CT and upstaged the disease in 4 patients. On the basis of the imaging findings alone, the additional information from PET/MRI would have led to a change in clinical management in 3 of 6 patients. The primary lesion showed a median SUV of 12.8 on PET/CT and 18.2 on PET/MRI (P = 0.03). SUVs, however, correlated strongly between the 2 modalities (ρ = 0.96, P < 0.001). Conclusion: Our pilot study supports the notion that PET/MRI has the potential to impact clinical decisions and treatment strategies in women with cervical cancer. Further studies are, however, warranted to define the value that PET/MRI adds to PET/CT.

Multiparametric MR for Solid Renal Mass Characterization

Multiparametric MR provides a noninvasive means for improved differentiation between benign and malignant solid renal masses. Although most large, heterogeneous renal masses are due to renal cell carcinoma, smaller "indeterminate" renal masses are being identified on cross-sectional imaging. Although definitive diagnosis of a solid renal mass may not always be possible by MR imaging, integrated evaluation of multiple MR imaging parameters can result in concise differential diagnosis. Multiparametric MR should be considered a critical step in the triage of patients with a solid renal mass for whom treatment options are being considered in the context of morbidity, prognosis, and mortality.

Cross-sectional imaging of seminal vesicles and vasa deferentia

A wide spectrum of pathologies, ranging from inconsequential degenerative and senile changes to clinically significant neoplasms, can affect seminal vesicles (SVs). With rapid rise in use of magnetic resonance imaging for evaluation of prostate in recent years an increasing number of cases of incidental SV pathologies are encountered by radiologists. Despite the high contrast resolution and high spatial resolution offered by multiparametric pelvic MRI, accurate diagnosis of SV processes can at times be challenging. In this article, we review the anatomy and embryology of the SVs and vasa deferentia and then explore the spectrum of diseases affecting them.

Prostate MRI: staging and decision-making

Multi-parametric prostate MRI (mpMRI) plays a critical role in the diagnosis, staging, and evaluation of treatment response in patients with prostate cancer. Radiologists, through an accurate and standardized interpretation of mpMRI, can clinically stage prostate cancer and help to risk stratify patients who may benefit from more invasive treatment or exclude patients who may be harmed by overtreatment. The purpose of this article is to describe key findings to accurately stage prostate cancer with mpMRI and to describe the contexts in which mpMRI is best applied.

Contribution of neural crest and GLAST+ Wnt1+ bone marrow pericytes with liver fibrogenesis and/or regeneration

BACKGROUND AND AIMS

Liver fibrosis results from cycles of liver damage and scar formation. We herein aimed at analysing neural crest cells and/or bone marrow stromal cells contribution to the liver.

METHODS

Two liver fibrosis and one hepatectomy model were applied on double-transgenic loxP-Cre mouse lines.

RESULTS

Increased numbers of glia with more complex processes were found in fibrotic livers. During embryonic development, only few cells were traced in the liver and bone marrow, in a minor fraction of mice of different neural crest reporter strains analysed: therefore, a neural crest origin of such cells is doubtful. In the fibrotic liver, a significantly higher incidence of endothelial cells and hepatocyte-like cells expressing the reporter gene Tomato were found in Wnt1-Cre-Tom and GLAST-CreERT2-Tom mice. Consistently, during early fibrogenesis stromal Wnt1-traced cells, with progenitor (CFU-F) properties, get likely mobilized to peripheral blood. Circulating adult Wnt1-traced cells are stromal cells and lack from the expression of other bone marrow and endothelial progenitor cells markers. Furthermore, in a 70% hepatectomy model GLAST⁺ Wnt1-traced pericytes were found to be mobilized from the bone marrow and the incidence of GLAST-traced hepatocyte-like cells was increased. Finally, GLAST-traced hepatocyte like-cells were found to maintain the expression of stromal markers.

CONCLUSIONS

Our data suggest a gliosis process during liver fibrogenesis. While neural crest cells probably do not contribute with other liver cell types than glia, GLAST⁺ Wnt1-traced bone marrow pericytes are likely a source of endothelial and hepatocyte-like cells after liver injury and do not contribute to scarring.

Efficacy of single-source rapid kV-switching dual-energy CT for characterization of non-uric acid renal stones: a prospective ex vivo study using anthropomorphic phantom

PURPOSE

To investigate the accuracy of rapid kV-switching single-source dual-energy computed tomography (rsDECT) for prediction of classes of non-uric-acid stones.

MATERIALS AND METHODS

Non-uric-acid renal stones retrieved via percutaneous nephrolithotomy were prospectively collected between January 2017 and February 2018 in a single institution. Only stones ≥ 5 mm and with pure composition (i.e., ≥ 80% composed of one component) were included. Stone composition was determined using Fourier Transform Infrared Spectroscopy. The stones were scanned in 32-cm-wide anthropomorphic whole-body phantom using rsDECT. The effective atomic number (Zeff), the attenuation at 40 keV (HU40), 70 keV (HU70), and 140 keV (HU140) virtual monochromatic sets of images as well as the ratios between the attenuations were calculated. Values of stone classes were compared using ANOVA and Mann-Whitney U test. Receiver operating curves and area under curve (AUC) were calculated. A p value < 0.05 was considered statistically significant.

RESULTS

The final study sample included 31 stones from 31 patients consisting of 25 (81%) calcium-based, 4 (13%) cystine, and 2 (6%) struvite pure stones. The mean size of the stones was 9.9 ± 2.4 mm. The mean Zeff of the stones was 12.01 ± 0.54 for calcium-based, 11.10 ± 0.68 for struvite, and 10.23 ± 0.75 for cystine stones (p < 0.001). Zeff had the best efficacy to separate different classes of stones. The calculated AUC was 0.947 for Zeff; 0.833 for HU40; 0.880 for HU70; and 0.893 for HU140.

CONCLUSION

Zeff derived from rsDECT has superior performance to HU and attenuation ratios for separation of different classes of non-uric-acid stones.

Liver Imaging Reporting and Data System (LI-RADS) v2018: diagnostic value of ancillary features favoring malignancy in hypervascular observations ≥ 10 mm at intermediate (LR-3) and high probability (LR-4) for hepatocellular carcinoma

OBJECTIVE

This study was conducted in order to assess the diagnostic accuracy of LI-RADS v2018 ancillary features (AFs) favoring malignancy applied to LR-3 and LR-4 observations on gadoxetate-enhanced MRI.

METHODS

In this retrospective dual-institution study, we included consecutive patients at high risk for hepatocellular carcinoma (HCC) imaged with gadoxetate disodium-enhanced MRI between 2009 and 2014 fulfilling the following criteria: (i) at least one LR-3 or LR-4 observation ≥ 10 mm; (ii) nonrim arterial phase hyperenhancement; and (iii) confirmation of benignity or malignancy by pathology or imaging follow-up. We compared the distribution of AFs between HCCs and benign observations and the diagnostic performance for the diagnosis of HCC using univariate and multivariate analyses. Significance was set at p value < 0.05.

RESULTS

Two hundred five observations were selected in 155 patients (108 M, 47 F) including 167 (81.5%) LR-3 and 38 (18.5%) LR-4. There were 126 (61.5%) HCCs and 79 (28.5%) benign lesions. A significantly larger number of AFs favoring malignancy were found in LR-3 and LR-4 lesions that progressed to HCC compared to benign lesions (p < 0.001 and p = 0.003, respectively). The most common AFs favoring malignancy in HCCs were hepatobiliary phase (HBP) hypointensity (p < 0.001), transitional phase hypointensity (p < 0.001), and mild-moderate T2 hyperintensity (p < 0.001). Sensitivity and specificity of AFs for the diagnosis of HCC ranged 0.8-76.2% and 86.1-100%, respectively. HBP hypointensity yielded the highest sensitivity but also the lowest specificity and was the only AF remaining independently associated with the diagnosis of HCC at multivariate logistic regression analysis (OR 14.83, 95% CI 5.81-42.76, p < 0.001).

CONCLUSIONS

Among all AFs, HBP hypointensity yields the highest sensitivity for the diagnosis of HCC.

KEY POINTS

• LR-3 and LR-4 observations diagnosed as HCC have a significantly higher number of ancillary features favoring malignancy compared to observations proven to be benign. • The presence of three or more ancillary features favoring malignancy has a high specificity (96.2%) for the diagnosis of HCC. • Among all ancillary features favoring malignancy, hepatobiliary phase hypointensity yields the highest sensitivity, but also the lowest specificity for the diagnosis of HCC.

Control of cell death/survival balance by the MET dependence receptor

Control of cell death/survival balance is an important feature to maintain tissue homeostasis. Dependence receptors are able to induce either survival or cell death in presence or absence of their ligand, respectively. However, their precise mechanism of action and their physiological importance are still elusive for most of them including the MET receptor. We evidence that pro-apoptotic fragment generated by caspase cleavage of MET localizes to the mitochondria-associated membrane region. This fragment triggers a calcium transfer from endoplasmic reticulum to mitochondria, which is instrumental for the apoptotic action of the receptor. Knock-in mice bearing a mutation of MET caspase cleavage site highlighted that p40MET production is important for FAS-driven hepatocyte apoptosis, and demonstrate that MET acts as a dependence receptor in vivo. Our data shed light on new signaling mechanisms for dependence receptors’ control of cell survival/death balance, which may offer new clues for the pathophysiology of epithelial structures.

Recurrent Rearrangements in PRKACA and PRKACB in Intraductal Oncocytic Papillary Neoplasms of the Pancreas and Bile Duct

BACKGROUND & AIMS

Intraductal oncocytic papillary neoplasms (IOPNs) of the pancreas and bile duct contain epithelial cells with numerous, large mitochondria and are cystic precursors to pancreatic ductal adenocarcinoma (PDAC) and cholangiocarcinoma (CCA), respectively. However, IOPNs do not have the genomic alterations found in other pancreatobiliary neoplasms. In fact, no recurrent genomic alterations have been described in IOPNs. PDACs without activating mutations in KRAS contain gene rearrangements, so we investigated whether IOPNs have recurrent fusions in genes.

METHODS

We analyzed 20 resected pancreatic IOPNs and 3 resected biliary IOPNs using a broad RNA-based targeted sequencing panel to detect cancer-related fusion genes. Four invasive PDACs and 2 intrahepatic CCAs from the same patients as the IOPNs, were also available for analysis. Samples of pancreatic cyst fluid (n = 5, collected before surgery) and bile duct brushings (n = 2) were analyzed for translocations. For comparison, we analyzed pancreatobiliary lesions from 126 patients without IOPN (controls).

RESULTS

All IOPNs evaluated were found to have recurring fusions of ATP1B1-PRKACB (n = 13), DNAJB1-PRKACA (n = 6), or ATP1B1-PRKACA (n = 4). These fusions also were found in corresponding invasive PDACs and intrahepatic CCAs, as well as in matched pancreatic cyst fluid and bile duct brushings. These gene rearrangements were absent from all 126 control pancreatobiliary lesions.

CONCLUSIONS

We identified fusions in PRKACA and PRKACB genes in pancreatic and biliary IOPNs, as well as in PDACs and pancreatic cyst fluid and bile duct cells from the same patients. We did not identify these gene fusions in 126 control pancreatobiliary lesions. These fusions might be used to identify patients at risk for IOPNs and their associated invasive carcinomas.

Liver stiffness measurement in patients with nodular regenerative hyperplasia undergoing magnetic resonance elastography

PURPOSE

Nodular regenerative hyperplasia (NRH) may mimic cirrhosis at imaging. We aim to investigate the effect of NRH on liver stiffness measurement (LSM) obtained with magnetic resonance elastography (MRE).

METHODS

This retrospective, Institutional Review Board-approved study included 37 subjects with NRH (Group 1) and no or minimal fibrosis (F0-F1), a control group (Group 2) made of 30 subjects with non-advanced fibrosis (F0-F2), and a control group (Group 3) made of 30 subjects with advanced fibrosis (F3-F4), all with available MRE. LSM was measured in each subject along with assessment of hepatic morphological features of cirrhosis and signs of portal hypertension. The significance of the difference in mean LSM between Group 1 and 2 and between Group 1 and 3 was evaluated using the Mann-Whitney U test. The difference in distribution of imaging features among groups was assessed using the Pearson χ2 or Fisher exact test.

RESULTS

The mean ± SD LSM in Group 1 (3.56 ± 1.10 kPa) was significantly higher compared to Group 2 (2.91 ± 0.52 kPa, P = 0.019) and significantly lower compared to Group 3 (7.18 ± 2.08 kPa, P < 0.001). Twelve (32%) patients with NRH had LSM ≥ 4.11 kPa, and 6 (16%) patients had LSM ≥ 4.71 kPa. Surface nodularity (P = 0.032) and caudate lobe hypertrophy (P = 0.004) were more commonly visualized in Group 1 than in Group 2. At least one feature of portal hypertension was observed in 16 (43%) NRH subjects.

CONCLUSION

NRH may increase the LSM obtained with MRE and may represent a confounding factor when using liver stiffness for the non-invasive diagnosis of fibrosis.

Opposing Contributions of GABAergic and Glutamatergic Ventral Pallidal Neurons to Motivational Behaviors

The ventral pallidum (VP) is critical for invigorating reward seeking and is also involved in punishment avoidance, but how it contributes to such opposing behavioral actions remains unclear. Here, we show that GABAergic and glutamatergic VP neurons selectively control behavior in opposing motivational contexts. In vivo recording combined with optogenetics in mice revealed that these two populations oppositely encode positive and negative motivational value, are differentially modulated by animal's internal state, and determine the behavioral response during motivational conflict. Furthermore, GABAergic VP neurons are essential for movements toward reward in a positive motivational context but suppress movements in an aversive context. In contrast, glutamatergic VP neurons are essential for movements to avoid a threat but suppress movements in an appetitive context. Our results indicate that GABAergic and glutamatergic VP neurons encode the drive for approach and avoidance, respectively, with the balance between their activities determining the type of motivational behavior.

Expanding the Liver Imaging Reporting and Data System (LI-RADS) v2018 diagnostic population: performance and reliability of LI-RADS for distinguishing hepatocellular carcinoma (HCC) from non-HCC primary liver carcinoma in patients who do not meet strict LI-RADS high-risk criteria

BACKGROUND

Hepatocellular carcinoma (HCC) can be diagnosed using imaging criteria in patients at high-risk for HCC, according to Liver Imaging Reporting and Data System (LI-RADS) guidelines. The aim of this study was to determine the diagnostic performance and inter-rater reliability (IRR) of LI-RADS v2018 for differentiating HCC from non-HCC primary liver carcinoma (PLC), in patients who are at increased risk for HCC but not included in the LI-RADS 'high-risk' population.

METHODS

This retrospective HIPAA-compliant study included a 10-year experience of pathologically-proven PLC at two liver transplant centers, and included patients with non-cirrhotic hepatitis C infection, non-cirrhotic non-alcoholic fatty liver disease, and fibrosis. Two readers evaluated each lesion and assigned an overall LI-RADS diagnostic category, additionally scoring all major, LR-M, and ancillary features.

RESULTS

The final study cohort consisted of 27 HCCs and 104 non-HCC PLC in 131 patients. The specificity of a 'definite HCC' designation was 97% for reader 1 and 100% for reader 2. The IRR was fair for overall LI-RADS category and substantial for most major features.

CONCLUSION

In a population at increased risk for HCC but not currently included in the LI-RADS 'high-risk' population, LI-RADS v2018 demonstrated very high specificity for distinguishing pathologically-proven HCC from non-HCC PLC.

HEXIM1 Diffusion in the Nucleus Is Regulated by Its Interactions with Both 7SK and P-TEFb

How nuclear proteins diffuse and find their targets remains a key question in the transcription field. Dynamic proteins in the nucleus are classically subdiffusive and undergo anomalous diffusion, yet the underlying physical mechanisms are still debated. In this study, we explore the contribution of interactions to the generation of anomalous diffusion by the means of fluorescence spectroscopy and simulation. Using interaction-deficient mutants, our study indicates that HEXIM1 interactions with both 7SK RNA and positive transcription elongation factor b are critical for HEXIM1 subdiffusion and thus provides evidence of the effects of protein-RNA interaction on molecular diffusion. Numerical simulations allowed us to establish that the proportions of distinct oligomeric HEXIM1 subpopulations define the apparent anomaly parameter of the whole population. Slight changes in the proportions of these oligomers can lead to significant shifts in the diffusive features and recapitulate the modifications observed in cells with the various interaction-deficient mutants. By combining simulations and experiments, our work opens new prospects in which the anomaly α coefficient in diffusion becomes a helpful tool to infer alterations in molecular interactions.

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.

Enhancement pattern of hepatocellular adenoma (HCA) on MR imaging performed with Gd-EOB-DTPA versus other Gd-based contrast agents (GBCAs): An intraindividual comparison

PURPOSE

To conduct an intraindividual comparison of the enhancement pattern of hepatocellular adenoma (HCA) on dynamic MRI study obtained following the injection of Gadoxetic acid (Gd-EOB-DTPA) and other gadolinium-based contrast agents (GBCAs).

METHOD

This is a retrospective, Institutional Review Board-approved study conducted in a single institution. A search of medical records between 2008 and 2017 revealed 17 patients (all females) with at least one pathologically-proven HCA who underwent liver MRI with Gd-EOB-DTPA and another GBCA within 1 year. Enhancement of each lesion on hepatic arterial (HAP), portal venous (PVP), 2 min and 4-5 minutes phases was subjectively evaluated by two abdominal radiologists. Lesions were categorized as hyper-, iso- or hypointense compared to the surrounding liver parenchyma. The presence of a peripheral pseudocapsule was also recorded. The differences in lesion enhancement were assessed using the McNemar Test. A p-value <0.05 was considered statistically significant.

RESULTS

The final population included 35 HCAs (83% inflammatory subtype). There was no significant difference in lesion size (P = 0.708) and enhancement on HAP (P = 0.625) or PVP (P = 0.125). HCAs showed more frequently hypointensity on 2 min (13/35 vs. 1/35, P < 0.001) and 4-5 minutes (P < 0.001) images obtained after injection of Gd-EOB-DTPA compared to those obtained after other GBCAs. A pseudocapsule was more frequently noted after administration of Gd-EOB-DTPA (13/35 vs 1/35, P = 0.002).

CONCLUSIONS

Enhancement pattern of HCA differs significantly after the injection of Gd-EOB-DTPA compared to other GBCAs. Lesion hypointensity on 2 min and 4-5 minutes images is more frequent when using Gd-EOB-DTPA.