Role of prostaglandin D2 receptors in the pathogenesis of abdominal aortic aneurysm formation.

Prostaglandin D2 (PGD2) released from immune cells or other cell types activates its receptors, D prostanoid receptor (DP)1 and 2 (DP1 and DP2), to promote inflammatory responses in allergic and lung diseases. Prostaglandin-mediated inflammation may also contribute to vascular diseases such as abdominal aortic aneurysm (AAA). However, the role of DP receptors in the pathogenesis of AAA has not been systematically investigated. In the present study, DP1-deficient mice and pharmacological inhibitors of either DP1 or DP2 were tested in two distinct mouse models of AAA formation: angiotensin II (AngII) infusion and calcium chloride (CaCl2) application. DP1-deficient mice [both heterozygous (DP1+/-) and homozygous (DP1-/-)] were protected against CaCl2-induced AAA formation, in conjunction with decreased matrix metallopeptidase (MMP) activity and adventitial inflammatory cell infiltration. In the AngII infusion model, DP1+/- mice, but not DP1-/- mice, exhibited reduced AAA formation. Interestingly, compensatory up-regulation of the DP2 receptor was detected in DP1-/- mice in response to AngII infusion, suggesting a potential role for DP2 receptors in AAA. Treatment with selective antagonists of DP1 (laropiprant) or DP2 (fevipiprant) protected against AAA formation, in conjunction with reduced elastin degradation and aortic inflammatory responses. In conclusion, PGD2 signaling contributes to AAA formation in mice, suggesting that antagonists of DP receptors, which have been extensively tested in allergic and lung diseases, may be promising candidates to ameliorate AAA.

Perivascular adipose tissue in autoimmune rheumatic diseases.

Perivascular adipose tissue (PVAT) resides at the outermost boundary of the vascular wall, surrounding most conduit blood vessels, except for the cerebral vessels, in humans. A growing body of evidence suggests that inflammation localized within PVAT may contribute to the pathogenesis of cardiovascular disease (CVD). Patients with autoimmune rheumatic diseases (ARDs), e.g., systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), psoriasis, etc., exhibit heightened systemic inflammation and are at increased risk for CVD. Data from clinical studies in patients with ARDs support a linkage between dysfunctional adipose tissue, and PVAT in particular, in disease pathogenesis. Here, we review the data linking PVAT to the pathogenesis of CVD in patients with ARDs, focusing on the role of novel PVAT imaging techniques in defining disease risk and responses to biological therapies.

Perivascular Adipose Tissue and Vascular Perturbation/Atherosclerosis.

Atherosclerosis is orchestrated by complex interactions between vascular and inflammatory cells. Traditionally, it has been considered to be an intimal inflammatory disease, characterized by endothelial dysfunction, inflammatory cell recruitment, lipid oxidation, and foam cell formation. This inside-out signaling paradigm has been accepted as dogma for many years, despite the fact that inflammatory cells are far more prevalent in the adventitia compared with the intima. For decades, the origin of adventitial inflammation in atherosclerosis was unknown. The fact that these inflammatory cells were observed to cluster at the margin of perivascular adipose tissues-a unique and highly inflammatory adipose depot that surrounds most atherosclerosis-prone blood vessels-has stimulated interest in perivascular adipose tissue-mediated outside-in signaling in vascular pathophysiology, including atherosclerosis. The phenotype of perivascular adipocytes underlies the functional characteristics of this depot, including its role in adventitial inflammatory cell recruitment, trafficking to the intima via the vasa vasorum, and atherosclerosis perturbation. This review is focused on emerging concepts pertaining to outside-in signaling in atherosclerosis driven by dysfunctional perivascular adipose tissues during diet-induced obesity and recent strategies for atherosclerosis prediction and prognostication based upon this hypothesis.

Impact of intravenous access site on attenuation for thoracic computed tomographic angiography: A time-matched, nested, case-control study.

BACKGROUND: The objective of this study was to evaluate whether the choice of intravenous access (IVA) site affects aortic attenuation during thoracic computed tomographic angiography (T-CTA) and any associated risks with intravenous device placement. METHODS: All T-CTA exams performed between 1/1/2013 and 8/14/2015 were retrospectively reviewed to identify those performed with contrast media injection via alternative (i.e. non-antecubital) IVA (n = 1769). Using time matching, antecubital IVA exams (n = 1769) were selected as controls. For each exam, attenuation was measured in the ascending aorta. Patient and technical data was subsequently collected from all 3538 patients included in this study. Multiple linear regression was used to determine if IVA site affected attenuation. Lastly, data related to extravasations for the entire T-CTA cohort were collected and compared. RESULTS: Hand/wrist, arm, and central venous access device IVA were all equivalent to antecubital IVA in terms of attenuation (P = 0.579, P = 0.599, and P = 0.522 respectively). Forearm and intraosseous IVA had significantly higher attenuation (P = 0.010 and P = 0.002, respectively) than antecubital IVA. Right-sided IVA was associated with a small attenuation increase of 11 Hounsfield Units (P < 0.001) compared to left-sided IVA. In terms of extravasation, antecubital IVA was equivalent to hand/wrist, forearm, and upper arm IVA (P = 0.778, P = 0.060, and P = 0.090 respectively). CONCLUSIONS: Satisfactory aortic attenuation achieved with non-antecubital IVA is equivalent to attenuation achieved with antecubital IVA for T-CTA imaging. The risk of contrast media extravasation in peripheral IVA devices was relatively low, however, appropriate IVA site selection should be considered an important factor for successful administration of contrast media for future imaging studies. This prevents undue harm to patients through preventable device failures when using a peripheral IV device in areas of high flexion/range of movements undergoing pressure injection for contrast media.

Preprocedural planning with prospectively triggered multidetector row CT angiography prior to bronchial artery embolization in cystic fibrosis patients with massive hemoptysis.

STUDY OBJECTIVES: The aim of this study was to determine if electrocardiographically synchronized, prospectively triggered multidetector row computed tomography (ECG-MDR-CT) angiography of the aorta can accurately predict the location of ectopic bronchial arteries in patients with cystic fibrosis (CF) with massive hemoptysis prior to bronchial artery embolization (BAE). DESIGN AND SETTING: The study was a prospective, observational study from September 1, 2009 to June 30, 2011, conducted at a university hospital with an adult CF center. PATIENTS: The study included adult CF patients with massive hemoptysis. RESULTS: A total of four adult patients (mean [± SD] age = 31.5 ± 7.9 years) with CF and massive hemoptysis underwent ECG-MDR-CT angiography. The location of the bleeding source was predicted in each case based on lung pathology observed on ECG-MDR-CT angiography. All four patients eventually required BAE without the need for conventional aortograms since the locations of the bronchial arteries were determined prior to the procedure. Review of lung pathology and arterial networks from the ECG-MDR-CT angiography data limited the number of selective catheterizations necessary to complete the procedures. BAE resulted in complete resolution of hemoptysis in three patients and successful mitigation of the bleeding in the fourth patient until lung transplantation was performed 1 week later. CONCLUSIONS: ECG-MDR-CT angiography accurately depicted bronchial artery anatomy in CF patients with massive hemoptysis and provided excellent preprocedural planning for BAE. The information provided by ECG-MDR-CT angiography of the aorta prior to conventional angiography decreased the BAE radiation dose and contrast volume and likely reduced table time.

Swiss cheese interventricular septum presenting with catastrophic stroke: the potential role of ECG-gated CTA.

Ventricular septal defect is a common congenital cardiac condition that presents in a variety of morphologies. Less commonly, when an individual patient is found to have multiple ventricular septal defects, the term "Swiss cheese ventricular septal defect" is applied. Although not routinely utilized in clinical practice, electrocardiogram (ECG)-gated computed tomographic angiography (CTA) has been shown to provide utility in detecting intracardiac shunts, demonstrating promise in preventing acute strokes secondary to a paradoxical embolus from occurring; this is especially important when atypical cardiac septa are suspected. This case seeks to illustrate how usage of ECG-gated CTA can assist in early detection and prevention of adverse outcomes resulting from an atypical presentation of a ventricular septal defect.

Three Technologies That Will Guide Revascularization of Chronic Coronary Syndrome Patients into the 21st Century: A Review.

Although medical therapy is the preferred first-line treatment for patients with chronic coronary syndrome (CCS), revascularization remains an important consideration. We present a review that identifies the three diagnostic technologies most important to guiding the decision to revascularize patients with CCS: (1) cardiac computed tomography, (2) intracoronary imaging, and (3) lesion-specific physiological guidance.

Clinical experience with a chlorhexidine-coated PICC: A prospective, multicenter, observational study.

INTRODUCTION: This study evaluated a chlorhexidine-coated peripherally inserted central catheter (PICC) and the incidence of associated complications within both inpatient and outpatient populations. METHODS: This IRB-approved, multicenter, prospective observational study was performed at three large teaching hospitals in the US. All adults who required a PICC for ⩾14 days were considered. Patients were monitored throughout entire catheter dwell. Duplex venous ultrasounds were performed before insertion, after 10 to 14 days of dwell time, and upon removal. Data was collected from the hospital, outpatient clinic, and patient PICC diary records. RESULTS: A total of 103 patients, 56% male, with mean BMI 29 ± 8.8, were enrolled. The majority (79%) of patients were from high-risk groups-cancer, infectious diseases, transplant, and trauma. Primary treatment indications were antibiotics (66.99%) and chemotherapy (25.24%). Double lumen PICCs (59.2%) were favored clinically, as was basilic vein placement (71.84%). Mean catheter dwell was 47.01 ± 25.82 days. Three (3, 2.9%) central line-associated bloodstream infections (CLABSI) were reported. Four patients (4.6%) reported symptomatic catheter-related thrombosis (CRT), confirmed with ultrasound. Three patients (3.4%) had ultrasound-confirmed fibroblastic sleeve (FS). Eight patients (9.2%) who entered the study with pre-existing superficial thrombosis, had complete resolution at the time of catheter removal. The incidence of CLABSI was 0.82/1000 days. The combined CRT and FS rate was 6.9%. CONCLUSION: Based upon the observational findings of this study, chlorhexidine-coated PICC technology may be considered for use in patient populations who are at moderate to high-risk for catheter-related complications in both inpatient and outpatient settings.

The augmented role of pancreatic imaging in the era of endoscopic necrosectomy: an illustrative and pictorial review.

Endoscopic cystogastrostomy for mature pancreatic collections has long been recognized. However, FDA approval of newer lumen-apposing metallic stents in 2014 has now brought pancreatic necrosectomy to the endoscopic realm. Endoscopic drainage of Walled-off necrosis and direct endoscopic necrosectomy are technically challenging procedures with higher rates of complications. Collaborative clinical decision making both pre- and post-procedurally between the radiologist, endoscopist, and the surgeon can greatly improve outcomes in necrotizing pancreatitis. Herein, we review the basic pathophysiology that underlies progressive radiographic findings in NP, value of preprocedural imaging, current management algorithms, newer tools, and techniques as well as potential post-procedure complications on imaging follow-up after endoscopic interventions in necrotizing pancreatitis.

Early TIPS failure in association with left mesenterico-gonadal spontaneous portosystemic venous shunt; a case report.

Transjugular intrahepatic portosystemic shunt (TIPS) periprocedural thrombosis rates have fallen significantly since the introduction of polytetrafluoroethylene-covered stent grafts. We present a case of a cirrhotic patient with portal hypertension presenting with early TIPS thrombosis in association with an underlying competing spontaneous left mesenterico-gonadal venous shunt, an uncommon variant of spontaneous portal systemic shunt (SPSS). The patient presented with bleeding distal duodenal varices refractory to endovascular therapy, and although a successful TIPS procedure was performed for this indication, early thrombosis was determined by follow-up abdominopelvic computed tomographic angiography (CTA) scan. Despite undergoing a standard TIPS revision procedure, blood flow through the TIPS remained hepatofugal. During a TIPS revision, portal vein angiography revealed competing large inferior mesenteric vein (IMV) varices shunting into the left renal vein via the left gonadal vein. The initial abdominal CTA was later reviewed by a non-invasive cardiovascular radiologist, and the presence of the competing left mesenterico-gonadal shunt was retrospectively identified. Radiologists interpreting CTA exams should be aware of SPSS generally and mesenterico-gonadal shunts specifically. Pre-procedural knowledge of underlying SPSS can affect post procedural outcomes and should be emphasized in the final CTA report.

Congenital intravascular abdominal aortic band initially thought to be a metallic foreign body: Characterization using microanatomical CT reconstruction technique.

We present a patient with the initial misdiagnosis of a metallic foreign body in the abdominal aorta. Computed tomographic angiography utilizing microanatomical reconstruction technique revealed the structure to instead be a partially calcified abdominal aortic congenital fibrous band. Most congenital fibrous bands spanning the aortic lumen are proximal within the aorta and are thought to be supportive structures of the aortic valve leaflets. Congenital fibrous bands distal to the sinotubular junction are quite rare.

Coronary Artery Involvement in Segmental Arterial Mediolysis: A Case Report.

Segmental arterial mediolysis (SAM) is an increasingly recognized disorder affecting small- to medium-sized muscular arteries. A patient with SAM involving the visceral arteries who was also found to have multivessel coronary artery involvement is described. The patient underwent a battery of biochemical, imaging, and genetic tests to exclude other vasculitides and connective tissue disorders. The aim is to shed light on the potential for SAM to affect the coronary arteries and recommend screening of the coronary arteries of patients with SAM. © RSNA, 2019.

Identifying Coronary Artery Calcification on Non-gated Computed Tomography Scans.

Coronary artery calcification (CAC) provides an objective measure of coronary artery disease and can readily be identified on non-gated computed tomography (CT) scans with a high correlation with gated cardiac CT scans. This standardized protocol takes a step-wise approach to not only optimizing an image for the identification of calcification but also to distinguishing CAC from other common causes of calcification in the cardiac silhouette. Recognition of CAC on non-gated CT scans helps to identify a very powerful prognostic factor that can influence therapeutic interventions or downstream diagnostic testing without requiring a gated cardiac scan. These non-gated CT scans are often acquired as part of the routine care of the patient, and this data is readily available without another dose of ionizing radiation. This protocol allows for the precise and accurate extraction of this data for the purposes of retrospective data analysis in clinical research studies, but also in the clinical evaluation and management of patients.

Prostate brachytherapy seed migration to the heart seen on cardiovascular computed tomographic angiography.

Brachytherapy consists of placing radioactive sources into or adjacent to tumors, to deliver conformal radiation treatment. The technique is used for treatment of primary malignancies and for salvage in recurrent disease. Permanent prostate brachytherapy seeds are small metal implants containing radioactive sources of I-125, Pd-103, or Cs-131 encased in a titanium shell. They can embolize through the venous system to the lungs or heart and subsequently be detected by cardiovascular computed tomography. Cardiovascular imagers should be aware of the appearance of migrated seeds, as their presence in the chest is generally benign, so that unnecessary worry and testing are avoided. We report a case of a patient who underwent brachytherapy for prostate cancer and developed a therapeutic seeds embolus to the right ventricle.

Genome-wide analysis suggests a differential microRNA signature associated with normal and diabetic human corneal limbus.

Small non-coding RNAs, in particular microRNAs (miRNAs), regulate fine-tuning of gene expression and can impact a wide range of biological processes. However, their roles in normal and diseased limbal epithelial stem cells (LESC) remain unknown. Using deep sequencing analysis, we investigated miRNA expression profiles in central and limbal regions of normal and diabetic human corneas. We identified differentially expressed miRNAs in limbus vs. central cornea in normal and diabetic (DM) corneas including both type 1 (T1DM/IDDM) and type 2 (T2DM/NIDDM) diabetes. Some miRNAs such as miR-10b that was upregulated in limbus vs. central cornea and in diabetic vs. normal limbus also showed significant increase in T1DM vs. T2DM limbus. Overexpression of miR-10b increased Ki-67 staining in human organ-cultured corneas and proliferation rate in cultured corneal epithelial cells. MiR-10b transfected human organ-cultured corneas showed downregulation of PAX6 and DKK1 and upregulation of keratin 17 protein expression levels. In summary, we report for the first time differential miRNA signatures of T1DM and T2DM corneal limbus harboring LESC and show that miR-10b could be involved in the LESC maintenance and/or their early differentiation. Furthermore, miR-10b upregulation may be an important mechanism of corneal diabetic alterations especially in the T1DM patients.

Type IIIb Endoleak Associated With an Infected Thoracoabdominal Endograft.

We present a 63-year-old male patient who presented with vague abdominal pain after an endoluminal thoracoabdominal aneurysm repair. He was found to have an infected endograft and an associated type IIIb endoleak. We believe that the infection contributed to the fabric degradation along the endograft and resulted in an expanding endoleak. Graft explantation was not performed because of the patient's multiple comorbidities, and the endoleak was treated with an additional stent graft and suppressive antibiotics. Endograft infection may lead to endograft degradation and associated leak. Therefore, an infectious etiology, although rare, should be considered when evaluating a delayed type IIIb endoleak.

Pseudoaneurysm of the thoracic aorta sustained during exposure to a tornado diagnosed with ECG-synchronized CT aortography.

A case of a tornado victim with a delayed presentation of injury to the aortic isthmus is discussed. Tornado forces resemble the forces of high energy explosions, and the injuries that can occur as a result of these forces can be bizarre. The patient presented with the unique computed tomography (CT) findings of isolated pseudoaneurysm of the thoracic aorta in the absence of other traumatic injury to the thorax. Equivocal results of the initial CT aortogram (CTA) were confirmed with ECG-synchronized CTA (ECG-CTA), demonstrating the superiority of ECG-CTA as compared to standard CTA.

An ex vivo approach to complex renal artery aneurysm repair.

Ex vivo repair technique for a complex renal artery aneurysm may have several advantages. Smaller incision size and use of minimally invasive techniques may decrease incisional morbidity and improve recovery time, especially in patients with a high body mass index. Improved visualization afforded by back-table methods may also be valuable when repair of aneurysms involving multiple branches is necessary. We report of a successful case of laparoscopic nephrectomy, followed by back-table aneurysmorrhaphy and autotransplant, in a patient with a renal artery aneurysm.

Use of noncontrast computed tomography of the inferior vena cava for real-time imaging guidance for the placement of inferior vena cava filters.

Appropriate placement of an inferior vena cava (IVC) filter necessitates imaging of the renal veins because when an IVC filter is deployed its tip should be at or below the inferior aspect of the inferiormost renal vein. Traditionally, imaging during placement of IVC filters has been with conventional cavography and fluoroscopy. Recently, intravascular ultrasound has been used for the same purpose but with additional expense. Morbidly obese patients often exceed the weight limit of fluoroscopy tables. In addition, short obese patients are at risk of falling from narrow fluoroscopy tables. For such patients, computed tomography (CT) guidance is a viable alternative to conventional fluoroscopic guidance. IVC placement was performed in the CT suite for two obese patients who exceeded the weight limits of the available fluoroscopy tables. In one case, a Vena-Tech filter (Braun Medical, Melsungen, Germany) was placed using CT fluoroscopy. In the second case, a Recovery (Bard, Murray Hill, NJ) filter was placed using intermittent limited z-axis scanning. In the first case, the filter was placed below the level of the renal veins and above the confluence of the iliac veins, which is acceptable placement. In the second case, with refinement of technique, the filter tip was placed less than 1 cm below the inferiormost renal vein, which is considered optimal placement. CT of the IVC precisely images the renal veins and can characterize their number and their confluence with the IVC. CT guidance is a viable alternative to fluoroscopic guidance for the placement of IVC filters in morbidly obese patients.