Distance between the left atrium and the vertebral body is predictive of esophageal movement in serial MR imaging

Abstract

PURPOSE MRI or CT imaging can be used to identify the esophageal location prior to left atrial ablation but the esophagus may move making the location unreliable when ablating to minimize esophageal injury. The aim of this study was to evaluate esophageal position and movement based on serial MRI imaging with the goal of identifying imaging and clinical characteristics that can predict the esophageal movement. METHODS Fifty patients undergoing 190 MRI scans were analyzed. The relative position of the esophagus in each MRI along with clinical and imaging characteristics were quantified, including the gap between the LA and the vertebral body (GAP), an anatomic space in which the esophagus can move. RESULTS A mean of 3.8 MRIs were analyzed per patient. Sixteen patients (32.0%) experienced significant lateral esophageal movement of more than 10 mm. In the significant movement group, body mass index (BMI) was higher (33.0 ± 6.5 vs 28.8 ± 5.3, p=0.02) and the GAP was significantly larger (7.1 ± 2.5 vs 4.8 ± 5.1 mm, p=0.04). Multivariate logistic regression analysis revealed that the GAP ≤ 4.5 mm was the only independent predictor of the esophagus not moving (Odds Ratio=9.25, 95% confidence interval=1.72 to 49.67, p=0.0095). CONCLUSION A GAP of less than 4.5 mm between the LA and the vertebral body is associated with lack of esophageal movement (< 10 mm). This suggests that the measurement of GAP < 4.5 mm may be used to predict the esophageal location in patients undergoing atrial ablation.

Preoperative personalization of atrial fibrillation ablation strategy to prevent esophageal injury: Impact of changes in esophageal position

“…The larger AAR in women may be due to the gender difference in chest morphology. Indeed, the distance between the LA and the vertebral body may differ between genders and has been associated with the space around the esophagus 14 . The present study also suggests that LA dilatation may increase the risk of esophageal injury.…”

Higher contact force during radiofrequency ablation leads to a much larger increase in edema as compared to chronic lesion size

“…It is appealing to envison imaging approaches that could help determine extent of lesion during the procedure. Real‐time MRI techniques provide an immediate and direct means of measuring ablation‐related tissue changes in addition to improved visualization of the tissue, as shown by numerous prior studies . Despite this appeal of using MRI in real time, the techniques are still being developed and are not ready for clinical use .…”

“…Real-time MRI techniques provide an immediate and direct means of measuring ablation-related tissue changes in addition to improved visualization of the tissue, as shown by numerous prior studies. 8,[19][20][21] Despite this appeal of using MRI in real time, the techniques are still being developed and are not ready for clinical use. 22 As a result, one has to rely on indirect mea-surements and test for electrical isolation using functional assays.…”

Imaging for Risk Stratification in Atrial Fibrillation with Heart Failure

“…The esophagus is a mobile structure so the pre-imaging location might not be useful when ablating. Recent report has shown that if the gap between the posterior wall of the LA and the vertebral body is less than 4.5 mm then the OR of the esophagus not moving is 9.25 (95% confidence interval: 1.72 to 49.67) 42 . This can be quite useful when planning for ablation to minimize any esophageal injury.…”

“…Pre-imaging with MRI can also be used to define both the atrial structure as well structures including the esophagus (Figure 3) around it 42 . The esophagus is a mobile structure so the pre-imaging location might not be useful when ablating.…”