The Natural History of Splenic Artery Aneurysms: Factors That Predict Aneurysm Growth.

PURPOSE: To examine the natural history of splenic artery aneurysms (SAAs) at a single institution and assess the effect of patient factors and aneurysm characteristics on aneurysm growth. MATERIALS AND METHODS: This single-center retrospective study included patients with SAAs who underwent serial imaging over 30 years (1990-2020). Data regarding patient demographics and aneurysm characteristics were collected. The variables contributing to aneurysm growth were assessed using nonparametric tests for continuous variables and chi-square test for categorical variables. Multivariable linear regression was performed using aneurysm growth rate as a continuous dependent variable. RESULTS: A total of 132 patients were included in this study. The median maximum diameter of the SAAs was 15.8 mm (range, 4.0-50.0 mm). Growth over time was observed in 39% of the aneurysms, whereas the remaining 61% were stable in size. Of aneurysms that increased in size, the median aneurysm growth rate was 0.60 mm/y (range, 0.03-5.00 mm/y). Maximum aneurysm diameter of >2 cm and the presence of >50% mural thrombus were significant positive predictors for aneurysm growth (P = .020 and P = .022, respectively). Greater than 50% rim calcification was a significant negative predictor for aneurysm growth (P = .009) in multivariate analysis. CONCLUSIONS: A larger baseline SAA size, presence of mural thrombus, and lack of rim calcification are associated with increased aneurysm growth rate.

ACR Appropriateness Criteria® Pulsatile Abdominal Mass, Suspected Abdominal Aortic Aneurysm: 2023 Update.

Abdominal aortic aneurysm (AAA) is defined as abnormal dilation of the infrarenal abdominal aortic diameter to 3.0 cm or greater. The natural history of AAA consists of progressive expansion and potential rupture. Although most AAAs are clinically silent, a pulsatile abdominal mass identified on physical examination may indicate the presence of an AAA. When an AAA is suspected, an imaging study is essential to confirm the diagnosis. This document reviews the relative appropriateness of various imaging procedures for the initial evaluation of suspected AAA. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Individualized Ultrasound-Guided Intervention Phantom Development, Fabrication, and Proof of Concept.

Commercial ultrasound vascular phantoms lack the anatomic diversity required for robust pre-clinical interventional device testing. We fabricated individualized phantoms to test an artificial intelligence enabled ultrasound-guided surgical robotic system (AI-GUIDE) which allows novices to cannulate deep vessels. After segmenting vessels on computed tomography scans, vessel cores, bony anatomy, and a mold tailored to the skin contour were 3D-printed. Vessel cores were coated in silicone, surrounded in tissue-mimicking gel tailored for ultrasound and needle insertion, and dissolved with water. One upper arm and four inguinal phantoms were constructed. Operators used AI-GUIDE to deploy needles into phantom vessels. Two groin phantoms were tested due to imaging artifacts in the other two phantoms. Six operators (medical experience: none, 3; 1-5 years, 2; 5+ years, 1) inserted 27 inguinal needles with 81% (22/27) success in a median of 48 seconds. Seven operators performed 24 arm injections, without tuning the AI for arm anatomy, with 71% (17/24) success. After excluding failures due to motor malfunction and a defective needle, success rate was 100% (22/22) in the groin and 85% (17/20) in the arm. Individualized 3D-printed phantoms permit testing of surgical robotics across a large number of operators and different anatomic sites. AI-GUIDE operators rapidly and reliably inserted a needle into target vessels in the upper arm and groin, even without prior medical training. Virtual device trials in individualized 3-D printed phantoms may improve rigor of results and expedite translation.Clinical Relevance- Individualized phantoms enable rigorous and efficient evaluation of interventional devices and reduce the need for animal and human subject testing.

Preventing inadvertent drain removal using a novel catheter securement device.

Percutaneous drains have provided a minimally invasive way to treat a wide range of disorders from abscess drainage to enteral feeding solutions to treating hydronephrosis. These drains suffer from a high rate of dislodgement of up to 30% resulting in emergency room visits, repeat hospitalizations, and catheter repositioning/replacement procedures, which incur significant morbidity and mortality. Using ex vivo and in vivo models, a force body diagram was utilized to determine the forces experienced by a drainage catheter during dislodgement events, and the individual components which contribute to drainage catheter securement were empirically collected. Prototypes of a skin level catheter securement and valved quick release system were then developed. The system was inspired by capstans used in boating for increasing friction of a line around a central spool and quick release mechanisms used in electronics such as the Apple MagSafe computer charger. The device was tested in a porcine suprapubic model, which demonstrated the effectiveness of the device to prevent drain dislodgement. The prototype demonstrated that the miniaturized versions of technologies used in boating and electronics industries were able to meet the needs of preventing dislodgement of patient drainage catheters.

Provocative mesenteric angiography for occult gastrointestinal bleeding: a systematic review.

Occult gastrointestinal bleeding (GIB) is a challenge for physicians to diagnose and treat. A systematic literature search of the PubMed and Embase databases was conducted up to January 1, 2023. Eligible studies included primary research studies with patients undergoing provocative mesenteric angiography (PMA) for diagnosis or localization of occult GIB. Twenty-seven articles (230 patients) were included in the review. Most patients (64.8%) presented with lower GIB. The average positivity rate for provocative angiography was 48.7% (58% with heparin and 46.7% in thrombolytics). Embolization was performed in 46.4% of patients, and surgical management was performed in 37.5%. Complications were rare. PMA can be an important diagnostic and treatment tool but studies with high-level evidence and standardized protocols are needed to establish its safety and optimal use.

Interventional radiological therapies in colorectal hepatic metastases.

Colorectal malignancy is the third most common cancer and one of the prevalent causes of death globally. Around 20-25% of patients present with metastases at the time of diagnosis, and 50-60% of patients develop metastases in due course of the disease. Liver, followed by lung and lymph nodes, are the most common sites of colorectal cancer metastases. In such patients, the 5-year survival rate is approximately 19.2%. Although surgical resection is the primary mode of managing colorectal cancer metastases, only 10-25% of patients are competent for curative therapy. Hepatic insufficiency may be the aftermath of extensive surgical hepatectomy. Hence formal assessment of future liver remnant volume (FLR) is imperative prior to surgery to prevent hepatic failure. The evolution of minimally invasive interventional radiological techniques has enhanced the treatment algorithm of patients with colorectal cancer metastases. Studies have demonstrated that these techniques may address the limitations of curative resection, such as insufficient FLR, bi-lobar disease, and patients at higher risk for surgery. This review focuses on curative and palliative role through procedures including portal vein embolization, radioembolization, and ablation. Alongside, we deliberate various studies on conventional chemoembolization and chemoembolization with irinotecan-loaded drug-eluting beads. The radioembolization with Yttrium-90 microspheres has evolved as salvage therapy in surgically unresectable and chemo-resistant metastases.

ACR Appropriateness Criteria® Nontraumatic Aortic Disease.

Nontraumatic aortic disease can be caused by a wide variety of disorders including congenital, inflammatory, infectious, metabolic, neoplastic, and degenerative processes. Imaging examinations such as radiography, ultrasound, echocardiography, catheter-based angiography, CT, MRI, and nuclear medicine examinations are essential for diagnosis, treatment planning, and assessment of therapeutic response. Depending upon the clinical scenario, each of these modalities has strengths and weaknesses. Whenever possible, the selection of a diagnostic imaging examination should be based upon the best available evidence. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment. The purpose of this document is to assist physicians select the most appropriate diagnostic imaging examination for nontraumatic aortic diseases.

Postprocessing Imaging Techniques of the Computed Tomography Angiography in Trauma Patients for Preprocedural Planning.

Computed tomography provides a wealth of diagnostic information in the trauma patient including the presence of organ, bone, and vasculature injuries for the rapid triage of trauma patients. In the context of interventional radiology, appropriately protocoled studies can be reviewed for vascular injury and help focus the angiographic assessment of bleeding patients to ideally achieve earlier hemostasis. This article outlines various image-processing techniques such as multiplanar reformats, curved planar reformats, maximum intensity projections, and volume rendering to identify and more thoroughly characterize vascular injuries as a preprocedural planning tool to expedite endovascular hemostasis in a case-based format.

Capacity Prioritization Initiative Reduced the Wait Time for Port Placement and Facilitated Increased Volume of Port Placements at a Large County Health System.

DESCRIPTION OF THE PROBLEM: Wait time from request to placement of ports in interventional radiology had increased from 14 to 27 days over a 4-month period. The goal of this project was to reduce the wait time by 15% within 4 months while accommodating additional volume. INSTITUIONAL APPROACH TO ADDRESS PROBLEM: Capacity analysis revealed 2 bottlenecks: (1) inadequate provider capacity for preprocedural visits in interventional radiology clinic and (2) inadequate number of spots for port placement in the angiography schedule. The intervention consisted of: (1) 2 reserved slots in the attending physician's morning clinic schedule and (2) 3 daily guaranteed spots for port placement in the angiography suite. Both changes were integrated into the electronic medical record scheduling system. DESCRIPTION OF OUTCOMES: After the intervention, per biweekly period, the number of port requests increased by 17% (Preintervention: 16.6 ± 3.1, Postintervention: 20.1 ± 4.1, P = 0.03), the number of completed clinic visits increased by 19% (Preintervention: 16.7 ± 5.1, Postintervention: 20.5 ± 3.6, P = 0.05), and the number of port placements increased by 19% (Preintervention: 16.9 ± 3.9, Postintervention: 21.0 ± 3.5, P = 0.02). The average wait time from request to placement decreased by 22% (Preintervention: 22.2 ± 4.4 days, Postintervention: 18.3 ± 3.4 days, P = 0.03), driven by a 49% decrease in wait time between request and clinic visit (Preintervention: 11.0 ± 2.3 days, Postintervention: 7.4 ± 1.0 days, P = 0.03). CONCLUSIONS: Prioritization of clinic and angiography suite capacity, integrated into the electronic scheduling system, significantly reduced the wait time for port placement, even with significant increases in the volume of port requests.

Assessing the safety of transarterial locoregional delivery of low-density lipoprotein docosahexaenoic acid nanoparticles to the rat liver.

Hepatic-arterial infusion (HAI) of low-density lipoprotein (LDL) nanoparticles reconstituted with docosahexaenoic acid (DHA) (LDL-DHA) has been shown in a rat hepatoma model to be a promising treatment for hepatocellular carcinoma. To date, little is known regarding the safety of HAI of LDL-DHA to the liver. Therefore, we aimed to investigate the deposition, metabolism and safety of HAI of LDL-DHA (2, 4 or 8 mg/kg) in the rat. Following HAI, fluorescent labeled LDL nanoparticles displayed a biexponential plasma concentration time curve as the particles were rapidly extracted by the liver. Overall, increasing doses of HAI of LDL-DHA was well tolerated in the rat. Body weight, plasma biochemistry and histology were all unremarkable and molecular markers of inflammation did not increase with treatment. Lipidomics analyses showed that LDL-DHA was preferentially oxidized to the anti-inflammatory mediator, protectin DX. We conclude that HAI of LDL-DHA nanoparticles is not only safe, but provides potential hepatoprotective benefits.

Interventional Treatment of Hepatic Metastases from Colorectal Cancer.

Modern systemic therapies provide a significant survival benefit in metastatic colorectal cancer. Despite these advances, the durability of response remains limited and nearly all patients progress on systemic treatment. Colorectal liver metastases (CLM) develop in approximately half of patients with metastatic disease and contribute to mortality in most patients. In selected patients, surgical resection of hepatic metastases prolongs survival, indicating the benefits of the targeted treatment of CLM through alternate means. Minimally invasive interventional treatments offer the promise of treating CLM in a wider range of patients than those eligible for surgical resection. Thermal ablation and intra-arterial therapies, including chemoembolization and radioembolization, are commonly used in the treatment of CLM. Each of these treatment modalities will be discussed in detail with an emphasis on the available clinical data for each interventional treatment for CLM.

Comparison of radiofrequency and microwave ablation and identification of risk factors for primary treatment failure and local progression.

PURPOSE: To compare percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA) for treatment of Hepatocellular carcinoma (HCC) and to identify risk factors for treatment failure and local progression. METHODS: 145 unique HCC [87 (60%) RFA, 58 (40%) MWA] were retrospectively reviewed from a single tertiary medical center. Adverse events were classified as severe, moderate, or mild according to the Society of Interventional Radiology Adverse Event Classification system. Primary and secondary efficacy, as well as local progression, were determined using mRECIST. Predictors of treatment failure and time to local progression were analyzed using generalized estimating equations and Cox regression, respectively. RESULTS: Technical success was achieved in 143/145 (99%) HCC. There were 1 (0.7%) severe and 2 (1.4%) moderate adverse events. Of the 143 technically successful initial treatments, 136 (95%) completed at least one follow-up exam. Primary efficacy was achieved in 114/136 (84%). 9/22 (41%) primary failures underwent successful repeat ablation, so secondary efficacy was achieved in 128/136 (90%) HCC. Local progression occurred in 24 (19%) HCC at a median of 25 months (95% CI = 19-32 months). There was no difference in technical success, primary efficacy, or time to local progression between RFA and MWA. In HCC treated with MWA, same-day biopsy was associated with primary failure (RR = 9.0, 95% CI: 1.7-47, P = 0.015), and proximity to the diaphragm or gastrointestinal tract was associated with local progression (HR = 2.40, 95% CI:1.5-80, P = 0.017). CONCLUSION: There was no significant difference in primary efficacy or time to local progression between percutaneous RFA and MWA.

ACR Appropriateness Criteria® Radiologic Management of Iliofemoral Venous Thrombosis.

Iliofemoral venous thrombosis carries a high risk for pulmonary embolism, recurrent deep vein thrombosis, and post-thrombotic syndrome complicating 30% to 71% of those affected. The clinical scenarios in which iliofemoral venous thrombosis is managed may be diverse, presenting a challenge to identify optimum therapy tailored to each situation. Goals for management include preventing morbidity from venous occlusive disease, and morbidity and mortality from pulmonary embolism. Anticoagulation remains the standard of care for iliofemoral venous thrombosis, although a role for more aggressive therapies with catheter-based interventions or surgery exists in select circumstances. Results from recent prospective trials have improved patient selection guidelines for more aggressive therapies, and have also demonstrated a lack of efficacy for certain conservative therapies. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Thoracic Outlet Syndrome.

Thoracic outlet syndrome (TOS) is the clinical entity that occurs with compression of the brachial plexus, subclavian artery, and/or subclavian vein at the superior thoracic outlet. Compression of each of these structures results in characteristic symptoms divided into three variants: neurogenic TOS, venous TOS, and arterial TOS, each arising from the specific structure that is compressed. The constellation of symptoms in each patient may vary, and patients may have more than one symptom simultaneously. Understanding the various anatomic spaces, causes of narrowing, and resulting neurovascular changes is important in choosing and interpreting radiological imaging performed to help diagnose TOS and plan for intervention. This publication has separated imaging appropriateness based on neurogenic, venous, or arterial symptoms, acknowledging that some patients may present with combined symptoms that may require more than one study to fully resolve. Additionally, in the postoperative setting, new symptoms may arise altering the need for specific imaging as compared to preoperative evaluation. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Liquid Biopsy for Cancer: Review and Implications for the Radiologist.

Imaging and image-guided procedures play an imperative role in the screening, diagnosis, and surveillance of cancer. Although emerging imaging techniques now enable more precise molecular characterization of tumors, multigenetic tumor profiling for targeted therapeutic selection remains limited to direct tissue acquisition. Even in the context of targeted therapy, tumors adapt to acquire resistance. This necessitates serial monitoring, traditionally through tissue acquisition, to identify the molecular mechanism of resistance and to guide second-line therapy. An alternative to tissue acquisition is the collection of circulating tumor markers such as cell-free nucleic acids and circulating tumor cells in the peripheral blood. This noninvasive diagnostic approach is referred to as the liquid biopsy. The liquid biopsy is currently used clinically for therapeutic guidance when tissue acquisition is impossible or when the specimen is inadequate. It is also being studied in the context of screening, diagnosis, and surveillance. As cancer treatment continues to move toward a focus on precision medicine, this developing technology may alter and/or augment the role of imaging in the management of cancer. This review aims to outline the use of liquid biopsy in cancer and its potential impact on diagnostic imaging and image-guided procedures.

ACR Appropriateness Criteria® Clinically Suspected Vascular Malformation of the Extremities.

Vascular malformations of the extremities represent a wide spectrum of lesions, broadly divided into high-flow and low-flow categories. High-flow lesions include arteriovenous malformations and arteriovenous fistulas, while the more common low-flow lesions consist of venous and lymphatic malformations. The clinical presentation of vascular malformations is variable and can include extremity pain, discoloration, focal mass, or diffuse extremity enlargement. A vascular murmur can also be present and is more typical of high-flow lesions. While vascular malformations can often be diagnosed or strongly suspected by clinical features alone, imaging is often used to confirm the diagnosis, determine lesion characteristics and extent, and/or plan for treatment. Among the imaging options available, those usually appropriate for initial imaging of suspected vascular malformation are MR angiography without and with intravenous contrast, MRI without and with intravenous contrast, CT angiography with intravenous contrast, or US duplex Doppler. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.