2.4 Measurements
Measurements of the parameters were made using a digital caliper on each
posterior line under predefined points (CPL = a, b, c and MPL = d, e,
f), which are segments that touched the esophagus, with their related
esophageal routes are as follows: (1) the shortest distance from the
endocardium of LAPW to the anterior border of the esophagus. (2) The
thickness of the fat pad, if it existed. (3) The thickness of LAPW
myocardium. (4) The distance between the esophagus and ipsilateral
inferior PV ostia and the shortest distance from LA to the spine at the
left inferior PV level. The distance from the endocardium of LAPW to the
esophagus was measured from the density of the intra-cavitary contrast
that filled the LA to the anterior border of the esophagus (Figure 2).
The presence of a fat pad between the LAPW and the esophagus was
identified by an abrupt change in the signal density. The thickness of
the LAPW myocardium was measured from the density of the contrast agent
in the LA to the fat pad or the outline of the anterior esophageal wall
if no fat pad was present. All parameters were determined independently
by two cardiologists using axial planes and 3D CT images. If there were
discrepancies between those results, they were adjudicated by a third
investigator.