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.

LI-RADS: Diagnostic Performance of Hepatobiliary Phase Hypointensity and Major Imaging Features of LR-3 and LR-4 Lesions Measuring 10-19 mm With Arterial Phase Hyperenhancement

OBJECTIVE. The purpose of this study was to determine the diagnostic performance of hepatobiliary phase hypointensity and Liver Imaging Reporting and Data System (LI-RADS) major imaging features in the diagnosis of hepatocellular carcinoma (HCC) in hepatic lesions with arterial phase hyperenhancement (APHE) measuring 10-19 mm in patients at high risk of HCC. MATERIALS AND METHODS. A composite reference standard of pathologic analysis and imaging follow-up was used. The diagnostic performance (sensitivity and specificity) of hepatobiliary phase hypointensity and LI-RADS major imaging features other than APHE for the diagnosis of HCC was assessed and compared by means of a logistic regression model. RESULTS. This retrospective dual-institution study included 189 LI-RADS LR-3 and LR-4 lesions measuring 10-19 mm and having APHE in 144 consecutively registered patients (96 men, 48 women; mean age, 58 years). Hepatobiliary phase hypointensity had significantly higher sensitivity (84% [92/109], p < 0.00001) than major imaging features in the diagnosis of HCC but lower specificity (84% [67/80]; p = 0.01). However, hepatobiliary phase hypointensity in LR-3 observations measuring 10-19 mm and having APHE had moderately elevated sensitivity (73% [44/60]) and specificity (85%, 64/75). All three major imaging features had high specificity for the diagnosis of HCC, including 95% (76/80) for washout, 100% (80/80) for enhancing capsule, and 99% (79/80) for threshold growth. CONCLUSION. Major imaging features have high specificity for the diagnosis of HCC in lesions measuring 10-19 mm that have APHE. The finding of hepatobiliary phase hypointensity significantly improves sensitivity while moderately high specificity is maintained for the diagnosis of HCC in LR-3 lesions measuring 10-19 mm that exhibit APHE.

User and system pitfalls in liver imaging with LI-RADS

The Liver Imaging Reporting and Data System (LI-RADS) is a comprehensive system for standardizing the terminology, technique, interpretation, reporting, and data collection of liver imaging, created specifically for patients at risk for hepatocellular carcinoma. Over the past years, LI-RADS has been progressively implemented into clinical practice, but pitfalls remain related to user error and inherent limitations of the system. User pitfalls include the inappropriate application of LI-RADS to a low-risk patient population, incorrect measurement techniques, inaccurate assumptions about LI-RADS requirements, and improper usage of LI-RADS terminology and categories. System pitfalls include areas of discordance with the Organ Procurement and Transplantation Network (OPTN) as well as pitfalls related to rare ancillary features. This article reviews common user pitfalls in applying LI-RADS v2018 and how to avoid preventable errors and also highlights deficiencies of the current version of LI-RADS and how it might be improved in the future. Level of Evidence:3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019. J. Magn. Reson. Imaging 2019;50:1673-1686.

Diagnostic value of MR-based texture analysis for the assessment of hepatic fibrosis in patients with nonalcoholic fatty liver disease (NAFLD)

PURPOSE

To investigate the performance of MR-based texture analysis (TA) for the assessment of hepatic fibrosis in patients with nonalcoholic fatty liver disease (NAFLD).

METHODS

Fifty-four adult patients (33 females, 21 males, mean age 49.8 ± 13.5 years) with biopsy-proven NAFLD were enrolled and underwent MR imaging on a 1.5 T system. TA parameters were extracted on axial noncontrast 3D-GRE T1W images (slice thickness = 4.6 mm) using a commercially available research software (TexRAD). Receiver operating curves (ROC), areas under the ROC (AUROC) and 95% confidence intervals (CI) were calculated to assess the accuracy of each TA parameter for the diagnosis of significant (F ≥ 2) and advanced fibrosis (F ≥ 3). The correlation between TA and histopathological features of nonalcoholic steatohepatitis (NASH) was tested calculating the Spearman's rank correlation coefficient (ρ).

RESULTS

Thirty-seven (68%) subjects had significant fibrosis and 20 (37%) had advanced fibrosis. The TA parameters with the best performance were standard deviation (SD) and entropy, respectively, with AUROC 0.755 (95% CI 0.619-0.862, p ≤ 0.0002) and 0.769 (95% CI 0.634-0.873, p < 0.0001) for significant fibrosis and AUROC 0.746 (95% CI 0.609-0.854, p ≤ 0.0004) and 0.754 (95% CI 0.618-0.861, p ≤ 0.0002) for advanced fibrosis. SD and entropy demonstrated a moderate correlation with the degree of fibrosis (ρ = 0.457 and 0.480; p < 0.01). No significant correlation was found between TA parameters and other histopathological features of NASH.

CONCLUSIONS

Entropy and SD extracted on T1-weighted MR images have fair accuracy for the diagnosis of significant and advanced hepatic fibrosis in patients with NAFLD.

Multiparametric Magnetic Resonance Imaging Is Associated with Increased Medicare Spending in Prostate Cancer Active Surveillance

BACKGROUND

Multiparametric magnetic resonance imaging (mpMRI) may improve prostate cancer risk stratification and decrease the need for repeat biopsies in men on prostate cancer active surveillance (AS). However, the impact of mpMRI on AS-related healthcare spending has not been established.

OBJECTIVE

To characterize the impact of mpMRI on AS-related Medicare expenditures.

DESIGN, SETTING, AND PARTICIPANTS

Using Surveillance, Epidemiology, and End Results (SEER)-Medicare files, we identified men ≥66 yr old with localized prostate cancer diagnosed during 2008-2013.

OUTCOME MEASURES AND STATISTICAL ANALYSIS

With a validated algorithm, we classified men into AS with and without mpMRI groups. We then determined Medicare spending on AS in each group using inflation-adjusted, price-standardized Medicare payments for AS-related procedures (ie, prostate-specific antigen [PSA] tests, prostate biopsies, biopsy complications, and mpMRI). Multivariable median regression compared Medicare spending on AS for men who received mpMRI and those who did not.

RESULTS AND LIMITATIONS

We identified 9081 men on AS with a median follow-up of 45 mo (interquartile range 29-64 mo). Thirteen percent (N = 1225) received mpMRI. On multivariable median regression, receipt of mpMRI was associated with an additional $447 (95% confidence interval $409-487) in Medicare spending per year. We observed greater frequency of AS-related procedures and higher spending for identical procedures (eg, PSA or prostate biopsy) in the mpMRI group than in the non-mpMRI group (all p <  0.001).

CONCLUSIONS

Among Medicare beneficiaries on AS, mpMRI is associated with additional annual Medicare spending. Future studies are needed to determine optimal use of mpMRI during AS to maximize value.

PATIENT SUMMARY

Prostate magnetic resonance imaging (MRI) helps physicians determine which prostate cancers are aggressive and which can be monitored safely. We studied whether using MRI during prostate cancer monitoring (also called active surveillance) resulted in increased healthcare spending. There was a modest increase in spending, but this may be worthwhile if the use of MRI allows physicians to monitor prostate cancer more accurately.

Increasing Utilization of Multiparametric Magnetic Resonance Imaging in Prostate Cancer Active Surveillance

OBJECTIVE

To characterize the use of multiparametric magnetic resonance imaging (mpMRI) in male Medicare beneficiaries electing active surveillance for prostate cancer. mpMRI has emerged as a tool that may improve risk-stratification and decrease repeated biopsies in men electing active surveillance. However, the extent to which mpMRI has been implemented in active surveillance has not been established.

METHODS

Using Surveillance, Epidemiology, and End Results registry data linked to Medicare claims data, we identified men with localized prostate cancer diagnosed between 2008 and 2013 and managed with active surveillance. We classified men into 2 treatment groups: active surveillance without mpMRI and active surveillance with mpMRI. We then fit a multivariable logistic regression models to examine changing mpMRI utilization over time, and factors associated with the receipt of mpMRI.

RESULTS

We identified 9467 men on active surveillance. Of these, 8178 (86%) did not receive mpMRI and 1289 (14%) received mpMRI. The likelihood of receiving mpMRI over the entire study period increased by 3.7% (P = .004). On multivariable logistic regression, patients who were younger, white, had lower comorbidity burden, lived in the northeast and west, had higher incomes and lived in more urban areas had greater odds of receiving mpMRI (all P < .05).

CONCLUSION

From 2008 to 2013, use of mpMRI in active surveillance increased gradually but significantly. Receipt of mpMRI among men on surveillance for prostate cancer varied significantly across demographic, geographic, and socioeconomic strata. Going forward, studies should investigate causes for this variation and define ideal strategies for equitable, cost-effective dissemination of mpMRI technology.

Increasing utilization of multi-parametric magnetic resonance imaging in prostate cancer active surveillance

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Background: Multi-parametric resonance imaging (mpMRI) has emerged as a tool that may improve risk-stratification and decrease repeated biopsies in men electing active surveillance. However, the extent to which mpMRI has been implemented in active surveillance has not been established. Therefore, we sought to characterize the use of multiparametric magnetic resonance imaging (mpMRI) in Medicare beneficiaries electing active surveillance for prostate cancer. Methods: SEER-Medicare claims data, we identified men with localized prostate cancer diagnosed between 2008-2013 and managed with active surveillance. We classified men into two treatment groups: active surveillance without mpMRI and active surveillance with mpMRI. We then fit a multivariable logistic regression models to examine changing mpMRI utilization over time, and factors associated with the receipt of mpMRI. Results: We identified 9,467 men on active surveillance. Of these, 8,178 (86%) did not receive mpMRI and 1,289 (14%) received mpMRI. The likelihood of receiving mpMRI over the entire study period increased by 3.7% (p = 0.004). On multivariable logistic regression, patients who were younger, white, had lower comorbidity burden, lived in the northeast and west, had higher incomes and lived in more urban areas had greater odds of receiving mpMRI (all p < 0.05). Conclusions: From 2008-2013, use of mpMRI in active surveillance increased gradually but significantly. Receipt of mpMRI among men on surveillance for prostate cancer varied significantly across demographic, geographic and socioeconomic strata. Going forward, studies should investigate causes for this variation and define ideal strategies for equitable, cost-effective dissemination of mpMRI technology.

Cost implications of multi-parametric magnetic resonance imaging in prostate cancer active surveillance

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Background: Multi-parametric resonance imaging (mpMRI) has emerged to improve disease risk-stratification and decrease number of repeat biopsies in men on prostate cancer active surveillance (AS). However, the impact of mpMRI on cost of AS has not been established. We thus characterize the impact mpMRI on cost of AS in the Medicare population. Methods: Using SEER-Medicare files we identified men ≥66 years old with localized grade group I-II prostate cancer diagnosed 2008-2013. With an established algorithm, we classified men into active surveillance with and without mpMRI. We then determined cost of surveillance in each group using inflation-adjusted Medicare payments for surveillance-related procedures and their sequalae (i.e. PSA tests, prostate biopsies, post-biopsy complications and mpMRIs). Multivariable median regression compared cost and procedural-intensity for men who received mpMRI and those who did not. Results: We identified 9,081 men on AS with median follow up 45 months (IQR 29-64 months). 7,856 (87%) men did not receive mpMRI and 1,225 (13%) did. On multivariable median regression, receipt of mpMRI was associated with an additional $449 (95%CI $391-$507) in Medicare payments per year. Younger age, treatment in the west or northeast, greater population density and treatment later in the study period were associated with increased cost of AS. Conclusions: Among Medicare beneficiaries on AS, mpMRI is associated with additional annual cost to Medicare. MpMRI may be a marker of more stringent AS, which is likely more costly than watchful waiting. Future studies are needed to determine optimal use of mpMRI during AS to maximize value.

FRET Image Correlation Spectroscopy Reveals RNAPII-Independent P-TEFb Recruitment on Chromatin

Biochemical studies have revealed that the RNA Polymerase II (RNAPII) pause release is triggered by phosphorylation of the transcription machinery by the positive transcription elongation factor b (P-TEFb). However, there are no direct report that P-TEFb and RNA polymerase II interact in single living cells and the biophysical mechanisms mediating this association are still unclear. Förster resonance energy transfer (FRET) detects molecular interactions at the subcellular level. Time domain fluorescence lifetime imaging provides an accurate quantification of FRET efficiency, E_FRET, because it is fluorochrome concentration-independent and insensitive to fluorescence bleed-through. However, the way FRET signal is usually analyzed does not provide information about the areas where protein-protein interactions take place. In this work, we developed a method, dubbed FRET image correlation spectroscopy (FICS), which relied on FRET fluorescence lifetime imaging image acquisition and image correlation spectroscopy of E_FRET clusters to quantify the spatial distribution of interaction clusters in the nucleus. The combination of high content FRET microscopy with batch image analysis allowed a robust statistical analysis. By applying FICS, we characterized the area and density of interaction clusters between P-TEFb and RNAPII or histone H2A in single living cells. The FICS method applied to cells expressing genetically engineered mutated proteins confirmed that the histidine-rich domain of P-TEFb is required for its interaction with RNAPII. Furthermore, it demonstrated that P-TEFb was also located in close vicinity to histone H2A, independently of its interactions with RNAPII. These results support the hypothesis that P-TEFb dynamics on chromatin regulate its recruitment on RNAPII.

Schwann Cell Precursors Generate the Majority of Chromaffin Cells in Zuckerkandl Organ and Some Sympathetic Neurons in Paraganglia

In humans, neurosecretory chromaffin cells control a number of important bodily functions, including those related to stress response. Chromaffin cells appear as a distinct cell type at the beginning of midgestation and are the main cellular source of adrenalin and noradrenalin released into the blood stream. In mammals, two different chromaffin organs emerge at a close distance to each other, the adrenal gland and Zuckerkandl organ (ZO). These two structures are found in close proximity to the kidneys and dorsal aorta, in a region where paraganglioma, pheochromocytoma and neuroblastoma originate in the majority of clinical cases. Recent studies showed that the chromaffin cells comprising the adrenal medulla are largely derived from nerve-associated multipotent Schwann cell precursors (SCPs) arriving at the adrenal anlage with the preganglionic nerve fibers, whereas the migratory neural crest cells provide only minor contribution. However, the embryonic origin of the ZO, which differs from the adrenal medulla in a number of aspects, has not been studied in detail. The ZO is composed of chromaffin cells in direct contact with the dorsal aorta and the intraperitoneal cavity and disappears through an autophagy-mediated mechanism after birth. In contrast, the adrenal medulla remains throughout the entire life and furthermore, is covered by the adrenal cortex. Using a combination of lineage tracing strategies with nerve- and cell type-specific ablations, we reveal that the ZO is largely SCP-derived and forms in synchrony with progressively increasing innervation. Moreover, the ZO develops hand-in-hand with the adjacent sympathetic ganglia that coalesce around the dorsal aorta. Finally, we were able to provide evidence for a SCP-contribution to a small but significant proportion of sympathetic neurons of the posterior paraganglia. Thus, this cellular source complements the neural crest, which acts as a main source of sympathetic neurons. Our discovery of a nerve-dependent origin of chromaffin cells and some sympathoblasts may help to understand the origin of pheochromocytoma, paraganglioma and neuroblastoma, all of which are currently thought to be derived from the neural crest or committed sympathoadrenal precursors.

LI-RADS: a conceptual and historical review from its beginning to its recent integration into AASLD clinical practice guidance

The Liver Imaging Reporting and Data System (LI-RADS^®) is a comprehensive system for standardizing the terminology, technique, interpretation, reporting, and data collection of liver observations in individuals at high risk for hepatocellular carcinoma (HCC). LI-RADS is supported and endorsed by the American College of Radiology (ACR). Upon its initial release in 2011, LI-RADS applied only to liver observations identified at CT or MRI. It has since been refined and expanded over multiple updates to now also address ultrasound-based surveillance, contrast-enhanced ultrasound for HCC diagnosis, and CT/MRI for assessing treatment response after locoregional therapy. The LI-RADS 2018 version was integrated into the HCC diagnosis, staging, and management practice guidance of the American Association for the Study of Liver Diseases (AASLD). This article reviews the major LI-RADS updates since its 2011 inception and provides an overview of the currently published LI-RADS algorithms.

Ets-1 drives breast cancer cell angiogenic potential and interactions between breast cancer and endothelial cells

Ets-1 transcription factor overexpression in breast cancers is associated with invasive features and is associated with a poor prognosis. Beyond its role in driving carcinoma cell invasion, in this study, we wished to determine whether Ets-1 overexpression in cancer cells promotes angiogenesis by creating a paracrine pro-invasive environment for endothelial cells as well. To address this question, we set up different co-culture models of cancer cells with endothelial cells. Conditioned media from cancer cells induced endothelial cell proliferation, migration and morphogenesis in matrix models. Of note, co-culture assays in three-dimensional matrix models also revealed the reciprocal induction of cancer cell morphogenesis by endothelial cells, in support of an angiocrine action on tumor cells. Ets-1 emerged as a key regulator of the angiogenic potential of breast cancer cells, favoring their ability to induce, in a paracrine manner, the morphogenesis of endothelial cells and also to physically interact with the latter. Nevertheless, Ets-1 overexpression in cancer cells also restrained their chemoattractive potential for endothelial cells both in Boyden chambers and in ex vivo 3D co-cultures. Finally, Ets-1 modulation in breast cancer cells qualitatively altered the angiogenic pattern of experimental in vivo tumors, with a balance between vessel recruitment and intratumoral small capillaries sprouting. Taken together, our data highlight a critical and intriguing role for Ets-1 in the angiogenic potential of breast cancer cells, and reveal another facet of Ets-1 oncogenic activities.

White paper of the Society of Abdominal Radiology hepatocellular carcinoma diagnosis disease-focused panel on LI-RADS v2018 for CT and MRI

The Liver Imaging and Reporting Data System (LI-RADS) is a comprehensive system for standardizing the terminology, technique, interpretation, reporting, and data collection of liver imaging with the overarching goal of improving communication, clinical care, education, and research relating to patients at risk for or diagnosed with hepatocellular carcinoma (HCC). In 2018, the American Association for the Study of Liver Diseases (AASLD) integrated LI-RADS into its clinical practice guidance for the imaging-based diagnosis of HCC. The harmonization between the AASLD and LI-RADS diagnostic imaging criteria required minor modifications to the recently released LI-RADS v2017 guidelines, necessitating a LI-RADS v2018 update. This article provides an overview of the key changes included in LI-RADS v2018 as well as a look at the LI-RADS v2018 diagnostic algorithm and criteria, technical recommendations, and management suggestions. Substantive changes in LI-RADS v2018 are the removal of the requirement for visibility on antecedent surveillance ultrasound for LI-RADS 5 (LR-5) categorization of 10-19 mm observations with nonrim arterial phase hyper-enhancement and nonperipheral "washout", and adoption of the Organ Procurement and Transplantation Network definition of threshold growth (≥ 50% size increase of a mass in ≤ 6 months). Nomenclatural changes in LI-RADS v2018 are the removal of -us and -g as LR-5 qualifiers.

P-TEFb et Brd4

La physiologie d’une cellule est dictée par l’intégration des signaux qu’elle reçoit et la mise en place de réponses adaptées par le biais, entre autres, de programmes transcriptionnels adéquats. Pour assurer un contrôle optimal de ces réponses, des mécanismes de régulation ont été sélectionnés, dont un processus de pause transcriptionnelle et de levée de cette pause par P-TEFb (positive transcription elongation factor) et Brd4 (bromodomain-containing protein 4). Le dérèglement de ce processus peut conduire à l’apparition de pathologies. P-TEFb et Brd4 ont ainsi émergé au cours des dernières années comme des cibles thérapeutiques potentielles dans le cadre des cancers et du syndrome d‘immunodéficience acquise (sida) notamment.

[MET exon 14 splicing sites mutations: A new therapeutic opportunity in lung cancer]

The mutations leading to MET exon 14 skipping represent a new class of molecular alterations described in various cancers. These alterations are observed in 2 to 3 % of cases of non-small cell lung cancer (NSCLC). Several cases of NSCLC carrying such alterations and achieving objective response to MET tyrosine kinase inhibitorshave recently been published. This review summarizes the molecular mechanisms responsible for MET exon 14 skipping as well as the consequences of the loss of this exon on receptor activity. We also describe the clinical characteristics of patients with METΔ14 mutations. Finally, we address the issues related to the detection of these mutations in lung cancer, and the need to anticipate resistance to MET inhibitors.

Molecular Architecture of the Mouse Nervous System

The mammalian nervous system executes complex behaviors controlled by specialized, precisely positioned, and interacting cell types. Here, we used RNA sequencing of half a million single cells to create a detailed census of cell types in the mouse nervous system. We mapped cell types spatially and derived a hierarchical, data-driven taxonomy. Neurons were the most diverse and were grouped by developmental anatomical units and by the expression of neurotransmitters and neuropeptides. Neuronal diversity was driven by genes encoding cell identity, synaptic connectivity, neurotransmission, and membrane conductance. We discovered seven distinct, regionally restricted astrocyte types that obeyed developmental boundaries and correlated with the spatial distribution of key glutamate and glycine neurotransmitters. In contrast, oligodendrocytes showed a loss of regional identity followed by a secondary diversification. The resource presented here lays a solid foundation for understanding the molecular architecture of the mammalian nervous system and enables genetic manipulation of specific cell types.

RNA velocity of single cells

RNA abundance is a powerful indicator of the state of individual cells. Single-cell RNA sequencing can reveal RNA abundance with high quantitative accuracy, sensitivity and throughput1. However, this approach captures only a static snapshot at a point in time, posing a challenge for the analysis of time-resolved phenomena such as embryogenesis or tissue regeneration. Here we show that RNA velocity-the time derivative of the gene expression state-can be directly estimated by distinguishing between unspliced and spliced mRNAs in common single-cell RNA sequencing protocols. RNA velocity is a high-dimensional vector that predicts the future state of individual cells on a timescale of hours. We validate its accuracy in the neural crest lineage, demonstrate its use on multiple published datasets and technical platforms, reveal the branching lineage tree of the developing mouse hippocampus, and examine the kinetics of transcription in human embryonic brain. We expect RNA velocity to greatly aid the analysis of developmental lineages and cellular dynamics, particularly in humans.

A radiogenomic analysis of hepatocellular carcinoma: association between fractional allelic imbalance rate index and the liver imaging reporting and data system (LI-RADS) categories and features

OBJECTIVE

To evaluate the association between the liver imaging reporting and data system (LI-RADS) categories and features and the fractional allelic imbalance (FAI) rate index of hepatocellular carcinoma (HCC).

METHODS

The institutional review board approved this retrospective study. Medical records collected between January 2008 and December 2013 were reviewed to find patients with histologically confirmed HCC, FAI analysis, and CT or MR imaging of the liver. The final population included 71 patients (54 males, 17 females). Three radiologists reviewed the images using the LI-RADS v. 2014. The association between FAI and LI-RADS categories and features was tested using the Spearman's rank correlation coefficient (rho) and the Wilcoxon rank-sum test [low FAI (<40%) vs high FAI (≥40%)]. A p value < 0.007 was used as the threshold for statistical significance after application of the Bonferroni correction for multiple comparisons.

RESULTS

HCCs were classified as LR-3 (n = 4), LR-4 (n = 22), and LR-5 (n = 45). There was a positive correlation (rho = 0.264) between FAI rate index and LI-RADS category, although not statistically significant after Bonferroni correction (p = 0.024). 14 of the 20 (70%) HCCs with high FAI (≥40%) were categorized as LR-5, 6/20 (30%) as LR-4 and none as LR-3 (p = 0.377). Among the evaluated LI-RADS imaging features, only lesion size showed a statistically significant different distribution in tumors with high FAI compared to those with low FAI. HCCs with FAI ≥40% were larger (56 ± 42 mm) compared to those with FAI <40% (36 ± 30 mm; p = 0.005).

CONCLUSION

There was a positive correlation, although not statistically significant, between the LI-RADS diagnostic categories and the FAI rate of HCC. Tumors with high FAI were larger compared to those with low FAI. Advances in knowledge: HCCs with high (≥40%) FAI are larger compared to those with low (<40%) FAI.

Schwann cell precursor: a neural crest cell in disguise?

Schwann cell precursors (SCPs) are multipotent embryonic progenitors covering all developing peripheral nerves. These nerves grow and navigate with unprecedented precision, delivering SCP progenitors to almost all locations in the embryonic body. Within specific developing tissues, SCPs detach from nerves and generate neuroendocrine cells, autonomic neurons, mature Schwann cells, melanocytes and other cell types. These properties of SCPs evoke resemblances between them and their parental population, namely, neural crest cells. Neural crest cells are incredibly multipotent migratory cells that revolutionized the course of evolution in the lineage of early chordate animals. Given this similarity and recent data, it is possible to hypothesize that proto-neural crest cells are similar to SCPs spreading along the nerves. Here, we review the multipotency of SCPs, the signals that govern them, their potential therapeutic value, SCP's embryonic origin and their evolutionary connections. We dedicate this article to the memory of Wilhelm His, the father of the microtome and "Zwischenstrang", currently known as the neural crest.

Multipotent peripheral glial cells generate neuroendocrine cells of the adrenal medulla

Adrenaline is a fundamental circulating hormone for bodily responses to internal and external stressors. Chromaffin cells of the adrenal medulla (AM) represent the main neuroendocrine adrenergic component and are believed to differentiate from neural crest cells. We demonstrate that large numbers of chromaffin cells arise from peripheral glial stem cells, termed Schwann cell precursors (SCPs). SCPs migrate along the visceral motor nerve to the vicinity of the forming adrenal gland, where they detach from the nerve and form postsynaptic neuroendocrine chromaffin cells. An intricate molecular logic drives two sequential phases of gene expression, one unique for a distinct transient cellular state and another for cell type specification. Subsequently, these programs down-regulate SCP-gene and up-regulate chromaffin cell-gene networks. The AM forms through limited cell expansion and requires the recruitment of numerous SCPs. Thus, peripheral nerves serve as a stem cell niche for neuroendocrine system development.