Complex Inferior Vena Cava Filter Retrievals: Success Rate and Predictors of Adverse Events at a Large Specialized Referral Center.

BACKGROUND. Specialized inferior vena cava (IVC) filter referral centers can achieve improved retrieval outcomes, potentially facilitating complex retrievals after long filter dwell times. OBJECTIVE. The purpose of this study was to determine the success rate of complex IVC filter retrievals at a large specialized IVC filter referral center and to identify predictors of adverse events during complex retrievals. METHODS. This retrospective study included patients who underwent complex IVC filter retrieval from March 2014 to June 2018 at a large regional health system with specialized complex retrieval referral centers and interventional radiologists with expertise in such procedures. Complex retrievals methods included a range of loop snare, coaxial sheath, forceps, and snare techniques. Data were collected from the electronic medical record. The success rate of complex retrieval was determined. Factors associated with adverse events during retrieval procedures were explored. RESULTS. The study included 125 patients (51 women, 74 men; mean age, 60 years). The mean filter dwell time at retrieval was 47.5 months (median, 21.8 months). The complex retrieval success rate was 99.2% on the first attempt and 100.0% overall. A total of 11.2% (14/125) of patients experienced an adverse event during retrieval, including 10.4% (13/125) with minor and 0.8% (1/125) with major events. Prolonged dwell time was the only indication for complex retrieval that was significantly associated with adverse events (adverse event rate, 16.7% for patients with this indication vs 5.1% for patients without this indication; p = .04). In multiple regression analysis, the only significant independent predictor of adverse events was a filter dwell time of 5 years or longer (odds ratio, 6.98 [95% CI, 1.64-29.81]; p = .009). CONCLUSION. In a specialized referral system with expertise in complex retrieval methods, high retrieval success rates can be achieved in patients who have filters with long dwell times. Nonetheless, longer dwell times are associated with adverse events during retrieval procedures. CLINICAL IMPACT. The observations support performing early filter retrieval and referring patients who have filters with prolonged dwell times to specialized centers.

Thrombotic Risk Associated with Inferior Vena Cava Filter Placement in Patients with Heparin-Induced Thrombocytopenia.

PURPOSE: This study sought to define thromboembolic risk and mortality in patients with heparin-induced thrombocytopenia (HIT) undergoing inferior vena cava filter (IVCF) placement, in light of the American Society of Hematology's 2018 guidelines against routine use of IVCFs in this population. METHODS: A total of 26 patients with HIT who received IVCFs were retrospectively reviewed, and the outcomes of this group were compared with those of 4,707 controls with either HIT or IVCFs alone and with reported outcomes in prior studies. RESULTS: The patient group demonstrated 6- and 12-month mortality rates of 26.9% and 30.8%, respectively, which did not differ significantly from those of the control groups and were in line with published mortality rates in the literature. The measured thromboembolic risk of 19.2% in the patient group was also within the range of published rates for patients with HIT or IVCF alone. CONCLUSIONS: IVCF placement did not significantly increase the risk of thromboembolism or death in patients with HIT and may be a viable option in the subset of these patients who are not candidates for anticoagulation.

18F-NaF and 18F-FDG as molecular probes in the evaluation of atherosclerosis.

The early detection of atherosclerotic disease is vital to the effective prevention and management of life-threatening cardiovascular events such as myocardial infarctions and cerebrovascular accidents. Given the potential for positron emission tomography (PET) to visualize atherosclerosis earlier in the disease process than anatomic imaging modalities such as computed tomography (CT), this application of PET imaging has been the focus of intense scientific inquiry. Although 18F-FDG has historically been the most widely studied PET radiotracer in this domain, there is a growing body of evidence that 18F-NaF holds significant diagnostic and prognostic value as well. In this article, we review the existing literature on the application of 18F-FDG and 18F-NaF as PET probes in atherosclerosis and present the findings of original animal and human studies that have examined how well 18F-NaF uptake correlates with vascular calcification and cardiovascular risk.

Imaging Atherosclerosis by PET, With Emphasis on the Role of FDG and NaF as Potential Biomarkers for This Disorder.

Molecular imaging has emerged in the past few decades as a novel means to investigate atherosclerosis. From a pathophysiological perspective, atherosclerosis is characterized by microscopic inflammation and microcalcification that precede the characteristic plaque buildup in arterial walls detected by traditional assessment methods, including anatomic imaging modalities. These processes of inflammation and microcalcification are, therefore, prime targets for molecular detection of atherosclerotic disease burden. Imaging with positron emission tomography/computed tomography (PET/CT) using 18F-fluorodeoxyglucose (FDG) and 18F-sodium fluoride (NaF) can non-invasively assess arterial inflammation and microcalcification, respectively. FDG uptake reflects glucose metabolism, which is particularly increased in atherosclerotic plaques retaining macrophages and undergoing hypoxic stress. By contrast, NaF uptake reflects the exchange of hydroxyl groups of hydroxyapatite crystals for fluoride producing fluorapatite, a key biochemical step in calcification of atherosclerotic plaque. Here we review the existing literature on FDG and NaF imaging and their respective values in investigating the progression of atherosclerotic disease. Based on the large volume of data that have been introduced to the literature and discussed in this review, it is clear that PET imaging will have a major role to play in assessing atherosclerosis in the major and coronary arteries. However, it is difficult to draw definitive conclusions on the potential role of FDG in investigating atherosclerosis given the vast number of studies with different designs, image acquisition methods, analyses, and interpretations. Our experience in this domain of research has suggested that NaF may be the tool of choice over FDG in assessing atherosclerosis, especially in the setting of coronary artery disease (CAD). Specifically, global NaF assessment appears to be superior in detecting plaques in tissues with high background FDG activity, such as the coronary arteries.

Evolving Role of PET in Detecting and Characterizing Atherosclerosis.

Cardiovascular molecular imaging has focused on assessing myocardial perfusion and ventricular ejection fraction. These modalities target late downstream effects of the atherosclerotic disease process; this calls for a change of focus toward methods that can detect early arterial wall changes before macrocalcifications become visible on computed tomography angiography and provide a better understanding of the disease process. We summarize current knowledge on PET in atherosclerosis and highlight pertinent questions relating to the early detection of atherosclerosis. The future of PET in atherosclerosis may be early individualized quantification of the arteriosclerotic disease burden rather than exploration of features of individual arterial plaques.

Response Assessment Criteria and Their Applications in Lymphoma: Part 2.

Interim and end-of-treatment PET/CT have become central to the evaluation of Hodgkin and non-Hodgkin lymphoma. This review article seeks to aid clinical decision making by providing an overview of available data on the diagnostic and prognostic value of PET/CT imaging for response assessment and pretransplant evaluation in lymphoma. The relative strengths and limitations of these techniques in various disease subtypes and clinical scenarios are explored, along with their current standards for reporting and latest developments. Particular attention is given to response-adapted therapy, which is emerging as a cornerstone of clinical management.

A Study of the Feasibility of FDG-PET/CT to Systematically Detect and Quantify Differential Metabolic Effects of Chronic Tobacco Use in Organs of the Whole Body-A Prospective Pilot Study.

RATIONALE AND OBJECTIVES: The aim of this study was to assess the feasibility of 18F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) to systematically detect and quantify differential effects of chronic tobacco use in organs of the whole body. MATERIALS AND METHODS: Twenty healthy male subjects (10 nonsmokers and 10 chronic heavy smokers) were enrolled. Subjects underwent whole-body FDG-PET/CT, diagnostic unenhanced chest CT, mini-mental state examination, urine testing for oxidative stress, and serum testing. The organs of interest (thyroid, skin, skeletal muscle, aorta, heart, lung, adipose tissue, liver, spleen, brain, lumbar spinal bone marrow, and testis) were analyzed on FDG-PET/CT images to determine their metabolic activities using standardized uptake value (SUV) or metabolic volumetric product (MVP). Measurements were compared between subject groups using two-sample t tests or Wilcoxon rank-sum tests as determined by tests for normality. Correlational analyses were also performed. RESULTS: FDG-PET/CT revealed significantly decreased metabolic activity of lumbar spinal bone marrow (MVPmean: 29.8 ± 9.7 cc vs 40.8 ± 11.6 cc, P = 0.03) and liver (SUVmean: 1.8 ± 0.2 vs 2.0 ± 0.2, P = 0.049) and increased metabolic activity of visceral adipose tissue (SUVmean: 0.35 ± 0.10 vs 0.26 ± 0.06, P = 0.02) in chronic smokers compared to nonsmokers. Normalized visceral adipose tissue volume was also significantly decreased (P = 0.04) in chronic smokers. There were no statistically significant differences in the metabolic activity of other assessed organs. CONCLUSIONS: Subclinical organ effects of chronic tobacco use are detectable and quantifiable on FDG-PET/CT. FDG-PET/CT may, therefore, play a major role in the study of systemic toxic effects of tobacco use in organs of the whole body for clinical or research purposes.

Response Assessment Criteria and Their Applications in Lymphoma: Part 1.

The effectiveness of cancer therapy, both in individual patients and across populations, requires a systematic and reproducible method for evaluating response to treatment. Early efforts to meet this need resulted in the creation of numerous guidelines for quantifying posttherapy changes in disease extent, both anatomically and metabolically. Over the past few years, criteria for disease response classification have been developed for specific cancer histologies. To date, the spectrum of disease broadly referred to as lymphoma is perhaps the most common for which disease response classification is used. This review article provides an overview of the existing response assessment criteria for lymphoma and highlights their respective methodologies and validities. Concerns over the technical complexity and arbitrary thresholds of many of these criteria, which have impeded the long-standing endeavor of standardizing response assessment, are also discussed.

The value of radiologic interventions and (18)F-DOPA PET in diagnosing and localizing focal congenital hyperinsulinism: systematic review and meta-analysis.

PURPOSE: This systematic review and meta-analysis aimed to quantify the diagnostic performance of pancreatic venous sampling (PVS), selective pancreatic arterial calcium stimulation with hepatic venous sampling (ASVS), and (18)F-DOPA positron emission tomography (PET) in diagnosing and localizing focal congenital hyperinsulinism (CHI). PROCEDURES: This systematic review and meta-analysis was conducted according to the PRISMA statement. PubMed, EMBASE, SCOPUS and Web of Science electronic databases were systematically searched from their inception to November 1, 2011. Using predefined inclusion and exclusion criteria, two blinded reviewers selected articles. Critical appraisal ranked the retrieved articles according to relevance and validity by means of the QUADAS-2 criteria. Pooled data of homogeneous study results estimated the sensitivity, specificity, likelihood ratios and diagnostic odds ratio (DOR). RESULTS: (18)F-DOPA PET was superior in distinguishing focal from diffuse CHI (summary DOR, 73.2) compared to PVS (summary DOR, 23.5) and ASVS (summary DOR, 4.3). Furthermore, it localized focal CHI in the pancreas more accurately than PVS and ASVS (pooled accuracy, 0.82 vs. 0.76, and 0.64, respectively). Important limitations comprised the inclusion of studies with small sample sizes, high probability of bias and heterogeneity among their results. Studies with small sample sizes and high probability of bias tended to overestimate the diagnostic accuracy. CONCLUSIONS: This systematic review and meta-analysis found evidence for the superiority of (18)F-DOPA PET in diagnosing and localizing focal CHI in patients requiring surgery for this disease.

Amyloid-ß positron emission tomography imaging probes: a critical review.

The rapidly rising prevalence and cost of Alzheimer's disease in recent decades has made the imaging of amyloid-ß deposits the focus of intense research. Several amyloid imaging probes with purported specificity for amyloid-ß plaques are currently at various stages of FDA approval. However, a number of factors appear to preclude these probes from clinical utilization. As the available "amyloid specific" positron emission tomography imaging probes have failed to demonstrate diagnostic value and have shown limited utility for monitoring therapeutic interventions in humans, a debate on their significance has emerged. The aim of this review is to identify and discuss critically the scientific issues contributing to the extensive inconsistencies reported in the literature on their purported in vivo amyloid specificity and potential utilization in patients.