Plasma FABP4 levels are associated with left atrial fat volume in persistent atrial fibrillation and predict recurrence after catheter ablation.

BACKGROUND: Imaging techniques have shown the association between left atrial adipose tissue (LAAT) volume and atrial fibrillation (AF) risk. PURPOSE: To analyze 1) adipokines in peripheral and atrial plasma from patients undergoing AF ablation; 2) its association with LAAT volume measured by multislice CT and 3) its predictive value for AF recurrence. METHODS: Seventy consecutive patients undergoing AF catheter ablation were screened. Blood samples were extracted from the left atrium and peripheral vein before catheter ablation. Multiplex fluorimetric immunoassay, enzyme-linked immunoassay and Western blot techniques were used for analyzing some adipokines, fatty acid binding protein 4 (FABP4), and leptin and perilipin analysis, respectively. Patients were followed up with clinical visits until one year after ablation. Generalized additive regression (GAM) was used for determining the best indicator of LAAT volume. Logistic regression analysis determined the best predictor of AF recurrence after persistent AF catheter ablation. RESULTS: Our results showed 1) differences in the levels of FABP4 between peripheral and left atrial blood samples. 2) persistent AF patients had higher LAAT volume than those with paroxysmal AF (5.12 ±â€¯2.76 vs. 3.82 ±â€¯1.81 mL; p < 0.036). FABP4 was the best adipokine associated with LAAT in persistent AF (p < 0.01) 3) and predictive value for AF recurrence after catheter ablation (AUC-ROC 0.883 with 95% CI 0.739-1.028). CONCLUSIONS: Plasma FABP4 levels, which were associated with LAAT volume in persistent AF, can be predictors of recurrence after catheter ablation. Whether persistent AF patients require more intensive management and monitoring according to FABP4 deserves further investigation.

Novel oncologic drugs: what they do and how they affect images.

Targeted therapies are designed to interfere with specific aberrant biologic pathways involved in tumor development. The main classes of novel oncologic drugs include antiangiogenic drugs, antivascular agents, drugs interfering with EGFR-HER2 or KIT receptors, inhibitors of the PI3K/Akt/mTOR pathway, and hormonal therapies. Cancer cells usurp normal signal transduction pathways used by growth factors to stimulate proliferation and sustain viability. The interaction of growth factors with their receptors activates different intracellular pathways affecting key tumor biologic processes such as neoangiogenesis, tumor metabolism, and tumor proliferation. The response of tumors to anticancer therapy can be evaluated with anatomic response assessment, qualitative response assessment, and response assessment with functional and molecular imaging. Angiogenesis can be measured by means of perfusion imaging with computed tomography and magnetic resonance (MR) imaging. Diffusion-weighted MR imaging allows imaging evaluation of tumor cellularity. The main imaging techniques for studying tumor metabolism in vivo are positron emission tomography and MR spectroscopy. Familiarity with imaging findings secondary to tumor response to targeted therapies may help the radiologist better assist the clinician in accurate evaluation of tumor response to these anticancer treatments. Functional and molecular imaging techniques may provide valuable data and augment conventional assessment of tumor response to targeted therapies. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.317115108/-/DC1.

The role of functional imaging in colorectal cancer.

OBJECTIVE: This article reviews the current and future contributions of functional imaging techniques to improve diagnosis, prognosis, and treatment of colorectal cancer. In addition, evolving roles and challenges for their implementation will be covered. CONCLUSION: Functional imaging now has a growing role in colorectal cancer. Recent developments in imaging technologies and validation of these newer imaging techniques may lead to significant improvements in the management of patients with colorectal cancer.