Comparison of Visceral Fat Measures with Cardiometabolic Risk Factors in Healthy Adults

<div><p>We aimed to evaluate the associations of visceral adiposity with cardiometabolic risk factors in normal subjects with integrated ¹⁸F-Fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT). A total of 58 normal subjects who underwent ¹⁸F-FDG PET/CT scan for cancer screening were included in this study. Volume and average Hounsfield unit (HU) of visceral adipose tissue (VAT) was measured from CT components of integrated PET/CT. Standardized uptake values (SUVmax) of liver, spleen, lumbar spine and ascending aorta (AA) were measured from PET components of integrated PET/CT. Body mass index (coefficient 78.25, p = 0.0259), glucose (37.62, p<0.0001), insulin (348.90, p = 0.0011), logarithmic transformation of homeostatic model assessment index-insulin resistance (-2118.37, p = 0.0007), and VAT HU (-134.99, p<0.0001) were independently associated with VAT volume. Glucose (0.1187, p = 0.0098) and VAT volume (-0.004, p<0.0001) were found to be associated with VAT HU. Both VAT volume and VAT HU of whole abdominal cavity is significantly associated with cardiometabolic risk factors.</p></div

Measurement of whole visceral adipose tissue.

<p>(A) Manually outlining volume-of-interest of the abdominal muscular wall, (B) defining voxels between -195HU and -45HU, making a template atlas, and (C) applying a template atlas to CT.</p

Previous studies of VAT volume.

<p>Previous studies of VAT volume.</p

Flow diagram of study subjects.

<p>Flow diagram of study subjects.</p

A decision tree model for predicting mediastinal lymph node metastasis in non-small cell lung cancer with F-18 FDG PET/CT

<div><p>We aimed to develop a decision tree model to improve diagnostic performance of positron emission tomography/computed tomography (PET/CT) to detect metastatic lymph nodes (LN) in non-small cell lung cancer (NSCLC). 115 patients with NSCLC were included in this study. The training dataset included 66 patients. A decision tree model was developed with 9 variables, and validated with 49 patients: short and long diameters of LNs, ratio of short and long diameters, maximum standardized uptake value (SUVmax) of LN, mean hounsfield unit, ratio of LN SUVmax and ascending aorta SUVmax (LN/AA), and ratio of LN SUVmax and superior vena cava SUVmax. A total of 301 LNs of 115 patients were evaluated in this study. Nodular calcification was applied as the initial imaging parameter, and LN SUVmax (≥3.95) was assessed as the second. LN/AA (≥2.92) was required to high LN SUVmax. Sensitivity was 50% for training dataset, and 40% for validation dataset. However, specificity was 99.28% for training dataset, and 96.23% for validation dataset. In conclusion, we have developed a new decision tree model for interpreting mediastinal LNs. All LNs with nodular calcification were benign, and LNs with high LN SUVmax and high LN/AA were metastatic Further studies are needed to incorporate subjective parameters and pathologic evaluations into a decision tree model to improve the test performance of PET/CT.</p></div

Characteristics of patients.

<p>Characteristics of patients.</p

A decision tree model.

<p>The model consists of 3 decision nodes: nodular calcification, LN SUVmax, and LN/AA. Nodular calcification was applied as the initial imaging parameter, and LN SUVmax was assessed as the second. LN/AA was required only to high LN SUVmax (≥3.95).</p

Characteristics of lymph nodes after excluding nodular calcification (n = 18).

<p>Characteristics of lymph nodes after excluding nodular calcification (n = 18).</p

Diagnostic performance of a decision tree model with both training and validation datasets.

<p>Diagnostic performance of a decision tree model with both training and validation datasets.</p

Clinical characteristics and laboratory findings of non-diabetic control subjects and type 2 diabetic patients.

<p>Values are mean ± SD, number of patients (%), median (interquartile range), and geometric means (95% CI) unless otherwise indicated. DM, diabetes mellitus; SBP, systolic blood pressure; DBP, diastolic blood pressure; AST, aspartate aminotransferase; ALT, alanine aminotransferase; eGFR, estimated glomerular filtration rate. *<i>P</i>-values were calculated using log-transformed values. ^†<i>P</i>-values were calculated by Student's <i>t</i>-test, Mann-Whitney u-test or Pearson <i>χ²</i> test where appropriate.</p