A Multicenter Assessment of Interreader Reliability of LI-RADS Version 2018 for MRI and CT.

Background Various limitations have impacted research evaluating reader agreement for Liver Imaging Reporting and Data System (LI-RADS). Purpose To assess reader agreement of LI-RADS in an international multicenter multireader setting using scrollable images. Materials and Methods This retrospective study used deidentified clinical multiphase CT and MRI and reports with at least one untreated observation from six institutions and three countries; only qualifying examinations were submitted. Examination dates were October 2017 to August 2018 at the coordinating center. One untreated observation per examination was randomly selected using observation identifiers, and its clinically assigned features were extracted from the report. The corresponding LI-RADS version 2018 category was computed as a rescored clinical read. Each examination was randomly assigned to two of 43 research readers who independently scored the observation. Agreement for an ordinal modified four-category LI-RADS scale (LR-1, definitely benign; LR-2, probably benign; LR-3, intermediate probability of malignancy; LR-4, probably hepatocellular carcinoma [HCC]; LR-5, definitely HCC; LR-M, probably malignant but not HCC specific; and LR-TIV, tumor in vein) was computed using intraclass correlation coefficients (ICCs). Agreement was also computed for dichotomized malignancy (LR-4, LR-5, LR-M, and LR-TIV), LR-5, and LR-M. Agreement was compared between research-versus-research reads and research-versus-clinical reads. Results The study population consisted of 484 patients (mean age, 62 years ± 10 [SD]; 156 women; 93 CT examinations, 391 MRI examinations). ICCs for ordinal LI-RADS, dichotomized malignancy, LR-5, and LR-M were 0.68 (95% CI: 0.61, 0.73), 0.63 (95% CI: 0.55, 0.70), 0.58 (95% CI: 0.50, 0.66), and 0.46 (95% CI: 0.31, 0.61) respectively. Research-versus-research reader agreement was higher than research-versus-clinical agreement for modified four-category LI-RADS (ICC, 0.68 vs 0.62, respectively; P = .03) and for dichotomized malignancy (ICC, 0.63 vs 0.53, respectively; P = .005), but not for LR-5 (P = .14) or LR-M (P = .94). Conclusion There was moderate agreement for LI-RADS version 2018 overall. For some comparisons, research-versus-research reader agreement was higher than research-versus-clinical reader agreement, indicating differences between the clinical and research environments that warrant further study. © RSNA, 2023 Supplemental material is available for this article. See also the editorials by Johnson and Galgano and Smith in this issue.

The role of BMP4 signaling in trophoblast emergence from pluripotency.

The Bone Morphogenetic Protein (BMP) signaling pathway has established roles in early embryonic morphogenesis, particularly in the epiblast. More recently, however, it has also been implicated in development of extraembryonic lineages, including trophectoderm (TE), in both mouse and human. In this review, we will provide an overview of this signaling pathway, with a focus on BMP4, and its role in emergence and development of TE in both early mouse and human embryogenesis. Subsequently, we will build on these in vivo data and discuss the utility of BMP4-based protocols for in vitro conversion of primed vs. naïve pluripotent stem cells (PSC) into trophoblast, and specifically into trophoblast stem cells (TSC). PSC-derived TSC could provide an abundant, reproducible, and ethically acceptable source of cells for modeling placental development.

One-step generation of a targeted knock-in calf using the CRISPR-Cas9 system in bovine zygotes.

BACKGROUND: The homologous recombination (HR) pathway is largely inactive in early embryos prior to the first cell division, making it difficult to achieve targeted gene knock-ins. The homology-mediated end joining (HMEJ)-based strategy has been shown to increase knock-in efficiency relative to HR, non-homologous end joining (NHEJ), and microhomology-mediated end joining (MMEJ) strategies in non-dividing cells. RESULTS: By introducing gRNA/Cas9 ribonucleoprotein complex and a HMEJ-based donor template with 1 kb homology arms flanked by the H11 safe harbor locus gRNA target site, knock-in rates of 40% of a 5.1 kb bovine sex-determining region Y (SRY)-green fluorescent protein (GFP) template were achieved in Bos taurus zygotes. Embryos that developed to the blastocyst stage were screened for GFP, and nine were transferred to recipient cows resulting in a live phenotypically normal bull calf. Genomic analyses revealed no wildtype sequence at the H11 target site, but rather a 26 bp insertion allele, and a complex 38 kb knock-in allele with seven copies of the SRY-GFP template and a single copy of the donor plasmid backbone. An additional minor 18 kb allele was detected that looks to be a derivative of the 38 kb allele resulting from the deletion of an inverted repeat of four copies of the SRY-GFP template. CONCLUSION: The allelic heterogeneity in this biallelic knock-in calf appears to have resulted from a combination of homology directed repair, homology independent targeted insertion by blunt-end ligation, NHEJ, and rearrangement following editing of the gRNA target site in the donor template. This study illustrates the potential to produce targeted gene knock-in animals by direct cytoplasmic injection of bovine embryos with gRNA/Cas9, although further optimization is required to ensure a precise single-copy gene integration event.

The Feasibility of Using Volumetric Phase-Contrast MR Imaging (4D Flow) to Assess for Transjugular Intrahepatic Portosystemic Shunt Dysfunction.

PURPOSE: To demonstrate the feasibility of detecting patency, stenosis, or occlusion of transjugular intrahepatic portosystemic shunt (TIPS) with four-dimensional (4D) flow MR imaging. MATERIALS AND METHODS: Sequential adult patients with TIPS were eligible for enrollment. Volumetric phase-contrast sequence was used to image TIPS. Particle tracing cine images were used for qualitative assessment of stenosis. TIPS was segmented to generate quantitative data sets of peak velocity. Segmentation and quantitative measurement of flow throughout an entire TIPS defined technical success. Doppler US was used for comparison. Venography, when available, and 6-month clinical follow-up were used as reference standards. RESULTS: 4D flow MR imaging was performed in 23 patient encounters and was technically successful in 16/23 (69.6%) encounters. Three cases demonstrated both focal turbulence and abnormal velocities (> 190 cm/s or < 90 cm/s) on 4D flow and had venography-confirmed stenosis (true-positive cases). Seven cases had normal velocities and no turbulence on 4D flow, and all were confirmed negative with clinical follow-up or venography (true-negative cases). Six cases had discordant 4D flow results, with abnormal velocities but no turbulence or focal turbulence but normal velocities. All 6 discordant cases had no evidence of dysfunction during 6-month follow-up. CONCLUSION: 4D flow MR imaging can detect TIPS patency and stenosis, but further investigation is required before it can be used to assess for TIPS dysfunction.

Design, fabrication, and testing of convex reflective diffraction gratings.

The convex reflective diffraction grating is an essential optical component that lends itself to various applications. In this work, we first outline the design principles of convex diffraction gratings from wavefront quality and efficiency perspectives. We then describe a unique fabrication method that allows for the machining of convex diffraction gratings with variable groove structure, which is extendable to rotationally non-symmetric convex diffraction grating substrates. Finally, we demonstrate two quantitative wavefront measurement methods and respective experimental validation.

A test for paedomorphism in domestic pig cranial morphology.

Domestic animals are often described as paedomorphic, meaning that they retain juvenile characteristics into adulthood. Through a three-dimensional landmark-based geometric morphometric analysis of cranial morphology at three growth stages, we demonstrate that wild boar (n = 138) and domestic pigs (n = 106) (Sus scrofa) follow distinct ontogenetic trajectories. With the exception of the size ratio between facial and neurocranial regions, paedomorphism does not appear to be the primary pattern describing the observed differences between wild and domestic pig cranial morphologies. The cranial phenotype of domestic pigs instead involves developmental innovation during domestication. This result questions the long-standing assumption that domestic animal phenotypes are paedomorphic forms of their wild counterparts.

Colorectal liver metastases: disappearing lesions in the era of Eovist hepatobiliary magnetic resonance imaging.

BACKGROUND: Hepatobiliary contrast enhanced MRI is known to be the most sensitive imaging modality for detection of colorectal hepatic metastasis. To date no study has investigated the rate of disappearing lesions with gadoxetic acid MR (Eovist/Primovist), or characterized the pathologic response of lesions which disappear on gadoxetic acid MR. METHODS: Retrospective review of hepatic resections for colorectal metastases between 01/2008 and 01/2014 was performed to evaluated the rate of disappearance of lesions on gadoxetic acid MR and the rate of complete pathologic response in the lesions that disappear. "Disappearing lesions" were lesions on baseline imaging that were not identifiable on pre-operative Eovist MRI. Complete pathologic response was defined as no viable tumor on pathology or by lack of recurrence within 1 year. RESULTS: In 23 patients, 200 colorectal metastases were identified on baseline imaging. On pre-operative Eovist MR 77 of the 200 lesions (38.5%) were "disappearing" lesions. At surgical pathology or 1 year follow-up imaging, 42 of 77 lesions (55%) demonstrated viable tumor (21) or recurrence (21). Thirty of 77 lesions (39%) were nonviable at pathology (10) or without evidence of recurrence at 1 year (20). 5 lesions were indeterminate. DISCUSSION: Despite disappearance on Eovist MR imaging (the most sensitive available imaging modality), 38.5% of all colorectal metastases disappeared and of those, 55% were viable.

Beyond Histologic Staging: Emerging Imaging Strategies in Colorectal Cancer with Special Focus on Magnetic Resonance Imaging.

Imaging plays an increasingly important role in the staging and management of colorectal cancer. In recent years, magnetic resonance imaging (MRI) has supplanted transrectal ultrasound as the preferred modality for the locoregional staging of rectal cancer. Furthermore, the advent of both diffusion-weighted imaging and hepatobiliary contrast agents has significantly enhanced the ability of MRI to detect colorectal liver metastases. In clinical practice, MRI routinely provides prognostic information, helps to guide surgical strategy, and determines the need for neoadjuvant therapies related to both the primary tumor and metastatic disease. Expanding on these roles for MRI, positron emission tomography (PET)/MRI is the newest clinical hybrid imaging modality and combines the metabolic information of PET with the high soft tissue contrast of MRI. The addition of PET/MRI to the clinical staging armamentarium has the potential to provide comprehensive state-of-the-art colorectal cancer staging in a single examination.

Phenotype and animal domestication: A study of dental variation between domestic, wild, captive, hybrid and insular Sus scrofa.

BACKGROUND: Identifying the phenotypic responses to domestication remains a long-standing and important question for researchers studying its early history. The great diversity in domestic animals and plants that exists today bears testament to the profound changes that domestication has induced in their ancestral wild forms over the last millennia. Domestication is a complex evolutionary process in which wild organisms are moved to new anthropogenic environments. Although modern genetics are significantly improving our understanding of domestication and breed formation, little is still known about the associated morphological changes linked to the process itself. In order to explore phenotypic variation induced by different levels of human control, we analysed the diversity of dental size, shape and allometry in modern free-living and captive wild, wild x domestic hybrid, domestic and insular Sus scrofa populations. RESULTS: We show that domestication has created completely new dental phenotypes not found in wild boar (although the amount of variation amongst domestic pigs does not exceed that found in the wild). Wild boar tooth shape also appears to be biogeographically structured, likely the result of post-glacial recolonisation history. Furthermore, distinct dental phenotypes were also observed among domestic breeds, probably the result of differing types and intensity of past and present husbandry practices. Captivity also appears to impact tooth shape. Wild x domestic hybrids possess second molars that are strictly intermediate in shape between wild boar and domestic pigs (third molars, however, showing greater shape similarity with wild boar) while their size is more similar to domestic pigs. The dental phenotypes of insular Sus scrofa populations found on Corsica and Sardinia today (originally introduced by Neolithic settlers to the islands) can be explained either by feralization of the original introduced domestic swine or that the founding population maintained a wild boar phenotype through time. CONCLUSIONS: Domestication has driven significant phenotypic diversification in Sus scrofa. Captivity (environmental control), hybridization (genome admixture), and introduction to islands all correspond to differing levels of human control and may be considered different stages of the domestication process. The relatively well-known genetic evolutionary history of pigs shows a similar complexity at the phenotypic level.

Limited utility of MRA for acute bowel ischemia after portal venous phase CT.

PURPOSE: Mesenteric ischemia and ischemic colitis are uncommon but potentially life-threatening causes of acute abdominal pain. Portal venous phase computed tomography (CT) is routinely ordered in the emergency room setting for abdominal pain, but subsequent MR angiography may be requested for additional evaluation of the mesenteric vasculature. We compare the concordance of CT and magnetic resonance angiography (MRA) for acute bowel ischemia. MATERIALS AND METHODS: Thirty-two patients who underwent contrast-enhanced MRA for bowel ischemia after having undergone CT evaluation within the preceding 2 weeks were identified. A retrospective review of imaging, treatment history, surgical, and pathology reports was conducted. Two radiologists each reviewed the imaging studies in a blinded fashion. RESULTS: Ten cases of bowel ischemia were confirmed by endoscopy and/or surgical pathology. CT correctly identified bowel findings in all cases. Intraobserver agreement between CT and MRA for all vessels was 0.68 and 0.63, highest for the superior mesenteric artery. Interobserver agreement was 0.74 for MRA and 0.78 for CT. Vascular findings were only directly mentioned in 10 of 32 CT reports (and 7 of 10 cases with confirmed bowel ischemia). MRA only detected two additional or alternative diagnoses. CONCLUSION: Portal venous phase CT and MRA demonstrate a high degree of concordance for vascular evaluation. Reviewed CT examinations were sufficient to assess the patency of the mesenteric vasculature, but vascular findings were not reported in most cases. A direct description within the report may have obviated the request for further MR imaging. MRA adds little value after portal venous CT in assessing bowel ischemia.

Mandibular shape and diet in extant primates: a 3D geometric morphometric analysis.

Establishing a link between mandibular morphology and diet in extant primates has long been a goal in biological anthropology because it should provide important insight into the diets of extinct primates, including fossil hominins. To date, efforts to explore this question have produced mixed results, largely perhaps due to a reliance on the use of 2D morphological data. Here, we report a study where we investigated whether 3D shape data would provide a clearer picture. We used geometric morphometrics to analyse 3D mandibular shape variation in a sample of > 200 primate specimens, representing individuals from 27 species and five families. Two sets of analyses investigated i) whether there was a relationship between mandibular shape and four standard dietary categories and ii) whether there was a relationship between mandibular shape and a well-known index of diet quality. We found an association between mandibular shape and the dietary categories when we employed raw Procrustes coordinates and allometry-free residuals, but the relationship was weak to non-existent when the effects of phylogeny were taken into account. We found no relationship between shape and the diet quality index, no matter whether the data were raw, corrected for the effects of allometry, corrected for the effects of phylogeny, or corrected for the effects of both allometry and phylogeny. Taken together, the results of the two sets of analyses suggest that there is a weak relationship between 3D mandibular shape and diet in extant primates. Allometry and phylogeny appear to be more important influences on the 3D shape of extant primate mandibles than is diet. We conclude from this that 3D analysis of mandibular shape is unlikely to further illuminate the diets of extinct primates, and research efforts should, therefore, be directed elsewhere.

Novel treatment of gastric outlet obstruction secondary to incarcerated inguinal hernia: percutaneous endoscopic gastrostomy tube.

A 93-year-old man presented with gastric outlet obstruction (GOO) secondary to a massive left inguinal hernia with incarcerated antrum. He reported a desire to avoid operative intervention, and given his comorbidities, such an operation carried high risk for perioperative complications. As such, we offered percutaneous endoscopic gastrostomy (PEG) tube placement, as this would allow intermittent decompression of the stomach to reduce the risk of obstruction and strangulation. He tolerated the procedure well and was discharged after several days of observation. He continues to do well at regular outpatient appointments. Although rare, GOO secondary to an incarcerated inguinal hernia is most likely to occur in a patient such as ours: elderly, comorbid and at high risk for perioperative complications. To our knowledge, this is the first documented case to be treated with a PEG tube, which can be a desirable and effective option in this subset of patients.

Germline ablation achieved via CRISPR/Cas9 targeting of NANOS3 in bovine zygotes.

NANOS3 is expressed in migrating primordial germ cells (PGCs) to protect them from apoptosis, and it is known to be a critical factor for germline development of both sexes in several organisms. However, to date, live NANOS3 knockout (KO) cattle have not been reported, and the specific role of NANOS3 in male cattle, or bulls, remains unexplored. This study generated NANOS3 KO cattle via cytoplasmic microinjection of the CRISPR/Cas9 system in vitro produced bovine zygotes and evaluated the effect of NANOS3 elimination on bovine germline development, from fetal development through reproductive age. The co-injection of two selected guide RNA (gRNA)/Cas9 ribonucleoprotein complexes (i.e., dual gRNA approach) at 6 h post fertilization achieved a high NANOS3 KO rate in developing embryos. Subsequent embryo transfers resulted in a 31% (n = 8/26) pregnancy rate. A 75% (n = 6/8) total KO rate (i.e., 100% of alleles present contained complete loss-of-function mutations) was achieved with the dual gRNA editing approach. In NANOS3 KO fetal testes, PGCs were found to be completely eliminated by 41-day of fetal age. Importantly, despite the absence of germ cells, seminiferous tubule development was not impaired in NANOS3 KO bovine testes during fetal, perinatal, and adult stages. Moreover, a live, NANOS3 KO, germline-ablated bull was produced and at sexual maturity he exhibited normal libido, an anatomically normal reproductive tract, and intact somatic gonadal development and structure. Additionally, a live, NANOS3 KO, germline-ablated heifer was produced. However, it was evident that the absence of germ cells in NANOS3 KO cattle compromised the normalcy of ovarian development to a greater extent than it did testes development. The meat composition of NANOS3 KO cattle was unremarkable. Overall, this study demonstrated that the absence of NANOS3 in cattle leads to the specific deficiency of both male and female germ cells, suggesting the potential of NANOS3 KO cattle to act as hosts for donor-derived exogenous germ cell production in both sexes. These findings contribute to the understanding of NANOS3 function in cattle and have valuable implications for the development of novel breeding technologies using germline complementation in NANOS3 KO germline-ablated hosts.

A deletion at the polled PC locus alone is not sufficient to cause a polled phenotype in cattle.

Dehorning is a common practice in the dairy industry, but raises animal welfare concerns. A naturally occurring genetic mutation (PC allele) comprised of a 212 bp duplicated DNA sequence replacing a 10-bp sequence at the polled locus is associated with the hornless phenotype (polled) in cattle. To test the hypothesis that the 10 bp deletion alone is sufficient to result in polled, a CRISPR-Cas9 dual guide RNA approach was optimized to delete a 133 bp region including the 10 bp sequence. Timing of ribonucleoprotein complex injections at various hours post insemination (hpi) (6, 8, and 18 hpi) as well as in vitro transcribed (IVT) vs synthetic gRNAs were compared. Embryos injected 6 hpi had a significantly higher deletion rate (53%) compared to those injected 8 (12%) and 18 hpi (7%), and synthetic gRNAs had a significantly higher deletion rate (84%) compared to IVT gRNAs (53%). Embryo transfers were performed, and bovine fetuses were harvested between 3 and 5 months of gestation. All fetuses had mutations at the target site, with two of the seven having biallelic deletions, and yet they displayed horn bud development indicating that the 10 bp deletion alone is not sufficient to result in the polled phenotype.

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.

Lung Metastasis Postradioembolization of Hepatocellular Carcinoma With Tumor in Vein.

Transarterial radioembolization (TARE) is one of the few treatment options available for infiltrative hepatocellular carcinoma with tumor in vein. This is backed by the published data showing marginally favorable toxicity profile compared with other locoregional and systemic therapies. Although lung shunt fraction studies are performed to prevent radiation injury to the lungs, TARE-induced embolization/metastasis to the lungs has not been reported before. We report an intriguing case of new lung metastases within 1 month after TARE for infiltrative hepatocellular carcinoma with a tumor in the vein, with only a slightly elevated but acceptable lung shunt fraction. This report brings to light the possibility of such a complication and argues for improved preprocedural assessment of a tumor in vein burden and embolization potential.

Efficient One-Step Knockout by Electroporation of Ribonucleoproteins Into Zona-Intact Bovine Embryos.

Somatic cell nuclear transfer or cytoplasm microinjection have been used to generate genome-edited farm animals; however, these methods have several drawbacks that reduce their efficiency. This study aimed to develop electroporation conditions that allow delivery of CRISPR/Cas9 system to bovine zygotes for efficient gene knock-out. We optimized electroporation conditions to deliver Cas9:sgRNA ribonucleoproteins to bovine zygotes without compromising embryo development. Higher electroporation pulse voltage resulted in increased membrane permeability; however, voltages above 15 V/mm decreased embryo developmental potential. The zona pellucida of bovine embryos was not a barrier to efficient RNP electroporation. Using parameters optimized for maximal membrane permeability while maintaining developmental competence we achieved high rates of gene editing when targeting bovine OCT4, which resulted in absence of OCT4 protein in 100% of the evaluated embryos and the expected arrest of embryonic development at the morula stage. In conclusion, Cas9:sgRNA ribonucleoproteins can be delivered efficiently by electroporation to zona-intact bovine zygotes, resulting in efficient gene knockouts.