Accuracy and reproducibility of CT right-to-left ventricular diameter measurement in patients with acute pulmonary embolism

<div><p>Background</p><p>Right ventricular (RV) dysfunction caused by acute pulmonary embolism (PE) is associated with poor short- and long-term prognosis. RV dilatation as a proxy for RV dysfunction can be assessed by calculating the right-to-left ventricle diameter (RV/LV) ratio on standard computed tomography pulmonary angiography (CTPA) images. It is unknown whether dedicated training is required to accurately and reproducibly measure RV/LV ratio therefore we aimed to assess these parameters in residents in internal medicine without experience in CTPA reading.</p><p>Methods</p><p>CTPA images of 100 patients with PE were assessed by three residents after single instruction, and one experienced thoracic radiologist. Maximum diameters were evaluated in the axial view by measuring the distance between the ventricular endocardium and the interventricular septum, perpendicular to the long axis of the heart. RV dilatation was defined as a ratio of ≥1.0. Interobserver accuracy and reproducibility was determined using Kappa statistics, Bland-Altman analysis and Spearman's rank correlation.</p><p>Results</p><p>The kappa statistic for the presence of RV dilatation of the residents compared to the experienced radiologist ranged from 0.83–0.94. The average interobserver difference in calculated RV/LV ratio’s (±SD) between the three residents was: -0.01 (SD0.11), 0.07 (SD0.14) and 0.06 (SD0.18) with an overall mean RV/LV diameter ratio of 1.04. In line with this, Spearman's rank correlation coefficients were 0.92, 0.88 and 0.85 respectively indicating very good correlation (p<0.01 for all).</p><p>Conclusion</p><p>After simple instruction, RV/LV diameter ratio assessment on CTPA images by clinical residents is accurate and reproducible, which is of help in identifying PE patients at risk.</p></div

Patient characteristics.

<p>Patient characteristics.</p

Cohen kappa statistic of the experienced thoracic radiologist reviewer 1 and the three residents internal medicine reviewer 2–4.

<p>Cohen kappa statistic of the experienced thoracic radiologist reviewer 1 and the three residents internal medicine reviewer 2–4.</p

Studies evaluating the interobserver RV/LV diameter ratio agreement.

<p>Studies evaluating the interobserver RV/LV diameter ratio agreement.</p

Association between liver biochemical test parameters and serum glucose.

<p>Tertiles of plasma LnALT, LnAST, LnGGT and serum LnTriglyceride (TG) (mmol/L) in association with nonfasting serum levels (mmol/L) of glucose. Asterisks (*p<0.05, **p<0.01, ***p<0.001) represents significant difference between groups using linear regression analysis, correcting for relation to sibling relationship, age, gender, smoking, alcohol use in g/day, and number of hepatotoxic medication. NS: not significant.</p

Computed tomography markers of liver steatosis in offspring of long-lived siblings and control subjects.

<p>Results are from linear mixed model and logistics regression analysis, correcting for age and gender (model 1) and additionally for smoking, body mass index, alcohol use in g/day, and number of hepatotoxic medications (model 2).</p>†<p>LS ratio were available in 131 offspring and 116 controls.</p><p>NAFLD: moderate-to-severe non-alcoholic fatty liver disease, L/S ratio: liver/spleen ratio, 95% CI: 95% confidence interval, HU: hounsfield units.</p

Nonfasting liver enzymes and triglycerides in offspring of long-lived siblings and control subjects.

<p>Results are from linear mixed models, correcting for age, gender, and correlation of sibling relationship (model 1) and additionally for smoking, body mass index, alcohol use in g/day and number of hepatotoxic medications (model 2). Models were fitted for natural log-transformed values of alanine transaminase (ALT), aspartate transaminase (AST), gamma-glutamyltransferase (GGT), and LnTriglycerides. Geometric means (95% confidence interval) are reported for transformed variables.</p

Subject demographics.

<p>Values are means (SE, standard error or 95% CI, confidence interval) or numbers (%). P values are from student’s t-test (^†), Pearson chi-square test (^‡), and from linear mixed model analysis, correcting for age, gender, BMI, and correlation of sibling relationship (^a). Models were fitted for natural log-transformed values for insulin. For transformed variables, data are presented as geometric means with 95% confidence intervals.</p><p>Age: age at serum screening, Hypertension: systolic blood pressure ≥130 mmHg and/or diastolic pressure ≥85 mmHg, or administration of antihypertensive medication, COPD: chronic obstructive pulmonary disease, Insulin: nonfasting serum insulin levels, Glucose: nonfasting serum glucose levels.</p