A systematic review of diagnostic and interventional techniques in non-occlusive hepatic artery hypoperfusion syndrome.

OBJECTIVE: This systematic review aims to elucidate the diagnostic capabilities of imaging techniques in identifying Non-Occlusive Hepatic Artery Hypoperfusion Syndrome (NOHAH) and to evaluate the efficacy and outcomes of splenic artery embolization (SAE), including the choice and placement of embolic agents. MATERIALS AND METHODS: A comprehensive literature search was conducted using PubMed, CINAHL, and Scopus databases, adhering to PRISMA guidelines. Fifteen studies encompassing 240 patients treated with embolization (using coils or Amplatzer Vascular Plugs (AVP)) were analyzed. Key metrics assessed included patient demographics, embolization techniques, embolic agents, technical success, radiologic findings pre- and post-embolization, and complication rates. RESULTS: Among the 240 patients studied, 177 (73.8%) were reported by gender, with a majority being male (127/177, 71.7%). Doppler ultrasonography (DUS) emerged as the primary initial screening tool in 80% of studies. The hepatic arterial resistive index (RI) was a critical parameter, with mean values significantly decreasing from 0.84 pre-embolization to 0.70 post-embolization (p < 0.001). All cases confirmed technical success via digital subtraction angiography, revealing delayed hepatic arterial filling without stenosis or thrombosis. Coils were the predominant embolic agent, used in 80.8% of patients, followed by AVP in 16.3%. The overall mortality rate was 4.58%, with 29 major and 3 minor complications noted. Notably, proximal placement of coils in the splenic artery was associated with lower mortality rates compared to distal placement and showed comparable complication rates to AVPs. CONCLUSION: DUS is a reliable screening modality for NOHAH, with post-SAE assessments showing significant improvements. The choice and location of embolization significantly impact patient outcomes, with proximal placement of coils emerging as a preferable strategy due to lower mortality rates and comparable complication profiles to alternative methods.

Digital light 4D printing of bioresorbable shape memory elastomers for personalized biomedical implantation.

Four-dimensional (4D) printing unlocks new potentials for personalized biomedical implantation, but still with hurdles of lacking suitable materials. Herein, we demonstrate a bioresorbable shape memory elastomer (SME) with high elasticity at both below and above its phase transition temperature (Ttrans). This SME can be digital light 3D printed by co-polymerizing glycerol dodecanoate acrylate prepolymer (pre-PGDA) with acrylic acid monomer to form crosslinked Poly(glycerol dodecanoate acrylate) (PGDA)-Polyacrylic acid (PAA), or PGDA-PAA network. The printed complex, free-standing 3D structures with high-resolution features exhibit shape programming properties at a physiological temperature. By tuning the pre-PGDA weight ratios between 55 wt% and 70 wt%, Ttrans varies between 39.2 and 47.2 ℃ while Young's moduli (E) range 40-170 MPa below Ttrans with fractural strain (εf) of 170 %-200 %. Above Ttrans, E drops to 1-1.82 MPa which is close to those of soft tissue. Strikingly, εf of 130-180 % is still maintained. In vitro biocompatibility test on the material shows > 90 % cell proliferation and great cell attachment. In vivo vascular grafting trials underline the geometrical and mechanical adaptability of these 4D printed constructs in regenerating the aorta tissue. Biodegradation of the implants shows the possibility of their full replacement by natural tissue over time. To highlight its potential for personalized medicine, a patient-specific left atrial appendage (LAA) occluder was printed and implanted endovascularly into an in vitro heart model. STATEMENT OF SIGNIFICANCE: 4D printed shape-memory elastomer (SME) implants particularly designed and manufactured for a patient are greatly sought-after in minimally invasive surgery (MIS). Traditional shape-memory polymers used in these implants often suffer from issues like unsuitable transition temperatures, poor biocompatibility, limited 3D design complexity, and low toughness, making them unsuitable for MIS. Our new SME, with an adjustable transition temperature and enhanced toughness, is both biocompatible and naturally degradable, particularly in cardiovascular contexts. This allows implants, like biomedical scaffolds, to be programmed at room temperature and then adapt to the body's physiological conditions post-implantation. Our studies, including in vivo vascular grafts and in vitro device implantation, highlight the SME's effectiveness in aortic tissue regeneration and its promising applications in MIS.

Pre-existing Hepatic Encephalopathy: Really a Contraindication to Elective TIPS?

PURPOSE: To evaluate the impact of pre-transjugular intrahepatic portosystemic shunt (TIPS) hepatic encephalopathy (HE) on developing post-TIPS HE. MATERIALS AND METHODS: In this retrospective, single center observational study, all patients who underwent successful TIPS placement between January 2005 and May 2020 with data pertaining to HE in their chart were included. Patient demographics and procedural details were recorded. Clinical outcomes post-TIPS, were collected and compared across patients with and without pre-TIPS HE. RESULTS: Of 326 included patients, 159 (159/326, 48.8%) had a history of pre-TIPS HE. In total those without a history of HE were more likely to develop HE during follow up (136 (136/167, 81.4%) vs 107 (107/159, 67.3%), p = 0.001). When evaluating for predictors of developing HE within 3 months of TIPS placement, no significant variables were found on logistic regression, including prior history of HE (HR 1.16 (95% CI 0.73-1.84), p = 0.529). Univariate and multivariate regression analysis, however, showed that a history of HE was predictive of developing HE at any point in the follow-up period (p = 0.002 and p = 0.008, respectively). However, on Kaplan-Meier analysis no significant difference in the development of HE (p = 0.574) or hospital admission for HE (p = 0.554) post-TIPS was seen between patients with and without pre-TIPS HE. Additionally, there was no difference in 3-month survival (p = 0.412) or overall survival post-TIPS survival (p = 0.798). CONCLUSION: Pre-TIPS HE did not predict the development of HE within 3 months of TIPS. Outcomes such as hospital admission and survivability were not different between patients with and without prior HE.

Intrahepatic cholangiocarcinoma: a dose threshold evaluation in those undergoing transarterial radioembolization.

Background: Intrahepatic cholangiocarcinoma (ICC) is a rare primary hepatic malignancy. One of the treatment strategies which has shown some promise is transarterial radioembolization (TARE). However, data on dose thresholds, arguably the most important aspect of the procedure itself, is still limited. The study aims to evaluate the relationship between dose to tumor and radiologic response in intrahepatic cholangiocarcinoma patients undergoing transarterial radioembolization. Methods: Twenty-patients who underwent treatment for 26 tumors were retrospectively reviewed. Radiologic response at 3-month was evaluated and post yttrium-90 bremsstrahlung single photon emission computerized tomography computed tomography was evaluated to determine tumor dose. Other factors such as particle load and activity per particle were evaluated. Results: The mean tumor dose for those with progressive disease or stable disease, partial response, and complete response (CR) by European Association for the Study of Liver (EASL) criteria for the glass cohort was 294±0, 465.4±292.4 and 951.8±666.5 Gy respectively (P=0.039). A receiver operating characteristic (ROC) curve analysis of tumor dose demonstrated an area under the curve (AUC) of 0.738 (P=0.038) with Youden-index analysis demonstrated a cutoff point of >541.7 Gy (sensitivity: 55.56%; specificity: 92.86%) for the glass cohort. Significantly longer survival was noted in those who achieved a CR [HR: 4.79 (95% CI: 1.41-16.25)] and those treated with glass as compared to resin [HR: 5.02 (95% CI: 1.23-20.55), P=0.025]. Of the 17 treatments in 13 patients which were done concomitantly with chemotherapy 7/17 (41.2%) required a delay in chemotherapy, however all patients reinitiated chemotherapy after a delay. Conclusions: There appears to be a relationship between tumor dose and radiologic response, with this study suggesting a target of ≥541.7 Gy being warranted in patients receiving treatment with glass microspheres.

Knee and Shoulder Vascular Anatomy.

In the past decade, angiographic studies have demonstrated neovessels in or in the vicinity of affected joints in many musculoskeletal conditions that used to be considered wear and tear joint disease, such as knee osteoarthritis, frozen shoulder, and overuse injuries. The novelty of this finding is showing the presence of neovascularity at an angiographically detectable level, as compared to histologically evident neovessels that had been discovered years ago. These neovessels have now become the target of interventions in a growing field called muscoskeletal embolotherapy. An in-depth and all-encompassing understanding of the vascular anatomy that could specifically assist performing of these procedures is paramount. Such an understanding will help ensure success in clinical outcomes and avoid much dreaded complications. This review discusses the vascular anatomy relevant to the 2 most commonly performed musculoskeletal embolotherapies, genicular artery embolization and transarterial embolization for frozen shoulder.

Post-Embolization Hemoglobin Changes: When to Consider Re-intervention.

PURPOSE: Decline in hemoglobin (Hgb) levels is common post-embolization, but there is no consensus on the classification of patients based on risk for re-bleeding or re-intervention. The current study evaluated post-embolization Hgb level trends with the goal of understanding the factors predictive of re-bleeding and re-intervention. MATERIALS AND METHODS: All patients who underwent embolization for gastrointestinal (GI), genitourinary, peripheral, or thoracic arterial hemorrhage from 01/2017 to 01/2022 were reviewed. Data included demographics, periprocedural pRBC transfusion (TF) or pressor requirements, and outcome. Lab data consisted of Hgb values pre-embolization, immediately post-embolization, and daily values on days 1-10 after embolization. Hgb trends were compared between patients across TF and re-bleeding outcomes. Regression model was used to examine factors predictive of re-bleeding and magnitude of Hgb reduction post-embolization. RESULTS: A total of 199 patients were embolized for active arterial hemorrhage. Perioperative Hgb level trends were similar for all sites and between TF + and TF- patients, showing a decline reaching a nadir within 6 days post-embolization followed by an upward trend. Maximum Hgb drift was predicted by GI embolization (p = 0.018), TF before embolization (p = 0.001), and use of vasopressor (p = 0.000). Patients with Hgb drop > 15% within the first two days post-embolization had a higher chance of having a re-bleeding episode (p = 0.04). CONCLUSION: Perioperative Hgb trends showed a consistent downward drift followed by an upward shift, irrespective of TF requirement status or site of embolization. Using a cut-off value of 15% Hgb reduction within the first two days post-embolization may be helpful to assess re-bleeding risk.

Cancer Immunology: Impact of Radioembolization of Hepatocellular Carcinoma on Immune Response Modulation.

Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer and the fourth most common cause of cancer mortality. The tumor microenvironment is increasingly recognized as having a central role in HCC carcinogenesis; factors such as tumor and immune cell interactions, cytokines, and extracellular matrix have key roles. Transarterial radioembolization (TARE) is a locoregional therapy for HCC that not only has a direct tumoricidal effect but also induces an immune response against tumor cells with subsequent immunogenic cell death. This TARE-induced tumor immunogenicity occurs through enhancement of tumor-associated antigen expression and recruitment and diversification of tumor-infiltrating lymphocytes. In addition, immunologic biomarkers, including neutrophil-to-lymphocyte ratio, lymphocyte count, and cytokine levels, may be useful for predicting outcomes after TARE. Early data are promising regarding the potential synergistic benefit of treatment algorithms that combine TARE and immunotherapies, and interest is growing in the clinical application of such combinations. The purpose of this article is to provide an overview of cancer immunology, summarize the available data on the biologic effects of TARE on local and systemic immune responses, and explore the potential role of the combination of TARE and immunotherapy for HCC.

Diffusion-weighted imaging (DWI) in diagnosis, staging, and treatment response assessment of multiple myeloma: a systematic review and meta-analysis.

OBJECTIVE: To evaluate the role of diffusion-weighted imaging (DWI) in the initial diagnosis, staging, and assessment of treatment response in patients with multiple myeloma (MM). MATERIALS AND METHODS: A systematic literature review was conducted in PubMed, the Cochrane Library, EMBASE, Scopus, and Web of Science databases. The primary endpoints were defined as the diagnostic performance of DWI for disease detection, staging of MM, and assessing response to treatment in these patients. RESULTS: Of 5881 initially reviewed publications, 33 were included in the final qualitative and quantitative meta-analysis. The diagnostic performance of DWI in the detection of patients with MM revealed pooled sensitivity and specificity of 86% (95% CI: 84-89) and 63% (95% CI: 56-70), respectively, with a diagnostic odds ratio (OR) of 14.98 (95% CI: 4.24-52.91). The pooled risk difference of 0.19 (95% CI: - 0.04-0.42) was reported in favor of upstaging with DWI compared to conventional MRI (P value = 0.1). Treatment response evaluation and ADCmean value changes across different studies showed sensitivity and specificity of approximately 78% (95% CI: 72-83) and 73% (95% CI: 61-83), respectively, with a diagnostic OR of 7.21 in distinguishing responders from non-responders. CONCLUSIONS: DWI is not only a promising tool for the diagnosis of MM, but it is also useful in the initial staging and re-staging of the disease and treatment response assessment. This can aid clinicians with earlier initiation or change in treatment strategy, which could have prognostic significance for patients.

Varicocele Embolization: Interventional Radiologist's Perspective.

The goal of this article is to review the patient selection criteria, technical pearls, and outcomes of percutaneous varicocele embolization. This article will provide a brief overview of the history of the procedure, angiographic approach, and materials used in contemporary embolization. The success rates and complications of the varicocele embolization will also be discussed.

Advanced Imaging in Multiple Myeloma: New Frontiers for MRI.

Plasma cell dyscrasias are estimated to newly affect almost 40,000 people in 2022. They fall on a spectrum of diseases ranging from relatively benign to malignant, the malignant end of the spectrum being multiple myeloma (MM). The International Myeloma Working Group (IMWG) has traditionally outlined the diagnostic criteria and therapeutic management of MM. In the last two decades, novel imaging techniques have been employed for MM to provide more information that can guide not only diagnosis and staging, but also treatment efficacy. These imaging techniques, due to their low invasiveness and high reliability, have gained significant clinical attention and have already changed the clinical practice. The development of functional MRI sequences such as diffusion weighted imaging (DWI) or intravoxel incoherent motion (IVIM) has made the functional assessment of lesions feasible. Moreover, the growing availability of positron emission tomography (PET)-magnetic resonance imaging (MRI) scanners is leading to the potential combination of sensitive anatomical and functional information in a single step. This paper provides an organized framework for evaluating the benefits and challenges of novel and more functional imaging techniques used for the management of patients with plasma cell dyscrasias, notably MM.

Lung shunt fraction quantification methods in radioembolization: What you need to know.

In some patients undergoing radioembolization, lung toxicity is a limiting factor when calculating their dose. At the same time, it is known that the lung shunt fraction (LSF) is overestimated by the mapping exam. Furthermore, there are multiple methods to measure LSF. Planar measurement is both the most commonly utilized and easiest to perform, however new dosimetry software provides the ability to use more advanced 3D techniques. This paper reviews the different LSF calculation methods and elucidates the available data comparing the techniques, clinical relevance, and dose calculation.

Emerging Targets for the Treatment of Osteoarthritis: New Investigational Methods to Identify Neo-Vessels as Possible Targets for Embolization.

Osteoarthritis (OA) is the major cause of disability, affecting over 30 million US adults. Continued research into the role of neovascularization and inflammation related to osteoarthritis in large-animal models and human clinical trials is paramount. Recent literature on the pathogenetic model of OA has refocused on low-level inflammation, resulting in joint remodeling. As a result, this has redirected osteoarthritis research toward limiting or treating joint changes associated with persistent synovitis. The overall goal of this review is to better understand the cellular and tissue-specific mechanisms of inflammation in relation to a novel OA treatment modality, Genicular Artery Embolization (GAE). This article also assesses the utility and mechanism of periarticular neovascular embolization for the treatment of OA with a particular emphasis on the balance between pro-angiogenic and anti-angiogenic cytokines, inflammatory biomarkers, and imaging changes.

Particle Distribution in Embolotherapy, How Do They Get There? A Critical Review of the Factors Affecting Arterial Distribution of Embolic Particles.

Embolization has tremendously evolved in recent years and has expanded to treatment of a variety of pathologic processes. There has been emerging evidence that the level of arterial occlusion and the distribution of embolic particles may play an important role in the clinical outcome. This is a comprehensive literature review to identify variables that play important role in determination of level of occlusion of blood vessels and distribution of embolic particles. The literature searches between 1996 to 2020 through PubMed and Ovid-MEDLINE yielded over 1030 articles of which 30 studies providing details on the level of occlusion are reviewed here. We divided the playing factors into characteristics of the particles, solution/injection and vascular bed. Accordingly, particle size, type and aggregation, compressibility/deformability, and biodegradability are categorized as the factors involving particles' behavioral nature. Infusion rate and concentration/dilution of the medium are related to the carrying solution. Hemodynamics and the arterial resistance are characteristics of the vascular bed that also play an important role in the distribution of embolic particles. Understanding and predicting the level of embolization is a complex multi-factor problem that requires more evidence, warranting further randomized controlled trials, and powered human and animal studies.

Hemorrhoid embolization: A review of current evidences.

Hemorrhoids are local vascular structure dilations in the lower rectum, associated with morbidity and reduced quality of life. Endovascular coil or particle embolization of the superior rectal arteries, known as Emborrhoid technique, is a minimally invasive, image-guided therapy that targets the hemorrhoidal plexus and reduces hemorrhage. The purpose of this review was to analyze the results of published studies to determine the efficacy, clinical outcomes, and morbidities associated with the endovascular occlusion of hemorrhoidal arteries for the treatment of internal hemorrhoids. Current evidences suggest that hemorrhoids treated by Emborrhoid technique using microcoils, embolic particles or a combination is safe with no reported serious complications. Hemorrhoid embolization can preserve the anal tone without direct anorectal trauma and maintain the hemorrhoidal tissue in place requiring minimal local wound care on an outpatient basis. However, due to the paucity of high-quality trials, further research is warranted to evaluate its long-term outcomes, compare its efficacy with other treatment modalities, and fully assess its role in the treatment of hemorrhoid.

Osteoarthritis-Related Knee Pain Treated With Genicular Artery Embolization: A Systematic Review and Meta-analysis.

BACKGROUND: Genicular artery embolization (GAE) is an innovative technique that has been investigated as a supplementary treatment method for chronic pain secondary to knee osteoarthritis (OA). PURPOSE: To evaluate the current evidence on the effectiveness and safety of GAE for OA-related knee pain. STUDY DESIGN: Systematic review; Level of evidence, 4. METHODS: A systematic literature search was conducted in the PubMed, Web of Science, EMBASE, and Scopus databases to identify studies related to knee OA treated with GAE. Treatment agents were categorized as Embozene, imipenem/cilastatin, resorbable microspheres, and polyvinyl alcohol. The main outcomes were the mean difference (MD) in pre- and postembolization pain based on the visual analog scale (VAS) or the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores as well as changes in the need for pain medication. Random- and fixed-effects models were applied for data analysis. RESULTS: Of 379 initially inspected publications, 11 (N = 225 patients; 268 knees) were included in the final review. The quality of the studies was fair in 8 and poor in 3-categorized according to the National Institutes of Health quality assessment tool. Overall, 119, 72, 13, and 21 patients were treated with imipenem/cilastatin, Embozene, resorbable microspheres, and polyvinyl alcohol, respectively. Symptomatic improvement was reported in all studies. The pooled effect size, characterized by MD, showed a significant improvement in the VAS and WOMAC pain scores, with better functional status after GAE. Pre- versus postembolization MDs in VAS scores ranged from 32 within the first week to 58 after a 2-year follow-up (equivalent to 54% and 80% improvement, respectively). There was a similar trend in the overall WOMAC scores, with MDs ranging from 28.4 to 36.8 (about 58% and 85% improvement, respectively). GAE resulted in a decreased need for pain medication for knee OA, with a 27%, 65%, and 73% decline in the number of patients who used opioids, nonsteroidal anti-inflammatory drugs, and intra-articular hyaluronic acid injection, respectively (P < .00001 for all). No significant difference between embolic agents was seen with regard to post-GAE pain reduction. No severe or life-threatening complications were reported. CONCLUSION: OA treated by GAE using different embolic particles can be considered generally safe, with good efficacy and no reported serious complications.

Magnetic resonance imaging features of coronavirus disease 2019 (COVID-19) pneumonia: The first preliminary case series.

RATIONALE AND OBJECTIVES: There is a rising onus on understanding the common features of COVID-19 pneumonia on different imaging modalities. In this study, we aimed to review and depict the common MRI features of COVID-19 pneumonia in our laboratory confirmed case series, the first comprehensive reported cohort in the literature. MATERIALS AND METHODS: Upon IRB approval, eight laboratory confirmed COVID-19 patients who presented to our outpatient imaging clinic underwent chest CT and, once various features of COVID-19 pneumonia were identified, a dedicated multisequence chest MRI was performed on the same day with an institutional protocol. Demographic data and the morphology, laterality and location of the lesions were recorded for each case. RESULTS: Five males and three females with the mean age of 40.63 ± 12.64 years old were present in this case series. Five cases had typical CT features with ground glass opacities and consolidations, readily visible on different MRI sequences. Three cases had indeterminate or atypical features which were also easily seen on MRI. The comprehensive review of MRI features for each case and representative images have been illustrated. CONCLUSION: Becoming familiar with typical findings of COVID-19 pneumonia in MRI is crucial for every radiologist. Although MRI is not the modality of choice for evaluation of pulmonary opacities, it has similar capabilities in detection of COVID-19 pneumonia when compared to chest CT.

Effectiveness of Transarterial Embolization in Treatment of Symptomatic Hepatic Hemangiomas: Systematic Review and Meta-analysis.

PURPOSE: To evaluate the current evidence for the effectiveness of transarterial embolization (TAE) in treatment of symptomatic hepatic hemangiomas. MATERIALS AND METHODS: A systematic literature review was conducted in PubMed, CINAHL and Scopus databases to identify studies of hepatic hemangiomas treated with transarterial embolization. Main outcome was defined as the mean difference between pre- and post-TAE hemangioma diameters. Treatment agents were categorized as Lipiodol based [bleomycin (L + BE), pingyangmycin (L + PYG) or ethanol (L + ethanol)] and non-Lipiodol based (polyvinyl-alcohol-only). Conventional random-effect meta-analysis technique was applied to analyze data. RESULTS: Of 3080 initially inspected publications, 21 studies were included in the meta-analysis comprising of 1450 patients with total of 1871 hemangiomas (36.2% male, mean age: 46.3 ± 3.6 years). One hundred and twenty-six, 1666, 41 and 38 lesions were treated with L + BE, L + PYG, L + ethanol and PVA, respectively. Median follow-up time after embolization was 12 months. Lipiodol-based treatments showed significant effect in reducing hemangioma size after TAE compared to PVA (P < 0.001). Pooled diameter reduction (cm) (95% confidence interval) was - 4.37( - 5.32, - 3.42), - 4.70( - 5.70, - 3.71), - 0.93( - 2.02, 0.16) for overall TAE treatment, Lipiodol-based and non-Lipiodol-based treatments, respectively. Main complications included post-embolization syndrome and transient liver enzyme elevation (pooled incidence for Lipiodol-based and non-Lipiodol-based techniques: 36% and 33%; and 37% and 0, respectively). No fatal complications were reported. Symptomatic improvement was reported in 63.3%-100% of the cases with majority of studies (15/21) reporting improvement in all cases (pooled response rate: 98%). CONCLUSIONS: Transarterial embolization with bleomycin, pingyangmycin or ethanol in combination with Lipiodol is safe and associated with reduced size of hemangiomas resulting in symptoms alleviation.