European Radiology: Potential value of carotid CTA in predicting atrial fibrillation

Atrial fibrillation (AF) is an important cause of ischaemic stroke and can lead to major intracranial vascular occlusion followed by numerous neurological sequelae
.
However, atrial fibrillation is often clinically ignored
due to its atypical and asymptomatic features.
There are reports that the incidence of silent atrial fibrillation is 1.
4% in the general population over 65 years of age and 13.
3%
in all patients with atrial fibrillation.
Therefore, early detection of atrial fibrillation before ischemic stroke occurs is key
in clinical practice.

In CT or MRI angiography, embolization tracking
is usually performed using a contrast agent (CM).
CTA of the brain or neck is often used to screen for neurological problems and is one of the
initial tests done when cerebrovascular disease is suspected.
We note that the following two pieces of information
on embolism tracking results can be obtained during CTA scans.
First, we obtained information on total embolization time (TTT), which is the sum
of CM transport time from the injection site to the right atrium (right atrial arrival time) and central circulation transit time (CTT) (time from right atrium to aorta).

Second, we can obtain the average degree of
enhancement from the enhancement fitting curve over the embolization tracking time.

A study published in the journal European Radiology recently investigated the value of TTT and mean enhancement obtained from carotid CTA images in predicting undiagnosed atrial fibrillation, and explored the association
between TTT, mean intensification, and echocardiographic parameters in patients with atrial fibrillation.

This single-center, retrospective study included patients
who underwent carotid CTA and a 24-hour Holter test.
TTT derived from carotid CTA and mean degree of enhancement during embolization tracking were defined as variables
of interest.
All patients underwent transthoracic echocardiography and left ventricular diastolic dysfunction and elevated left atrial pressure (LAP) were identified according to the 2016 American Society of Echocardiography/European Society for Cardiovascular Imaging guidelines
.

The final cohort consisted of 716 patients, 80 of whom developed atrial fibrillation
.
TTT (23.
8±5.
2 seconds) was significantly longer in the atrial fibrillation group than in the non-atrial fibrillation group (18.
7±2.
8 seconds).
P＜0.
001
。 The AS of the embolism traceability chart in the atrial fibrillation group was 0.
80 ± 0.
24, which was significantly lower than that of 1.
38 ± 0.
21 (P < 0.
001)
in the non-atrial fibrillation group.
TTT is associated with
significantly higher risk of atrial fibrillation (odds [OR]: 1.
36; P <0.
001) and elevated LAP (OR: 1.
46; P <0.
001).
In contrast, AS on the embolization tracking chart was not significantly associated with
atrial fibrillation or elevated LAP.

Figure A There were no cases of atrial fibrillation (total dose tracking time = 16.
5 seconds, mean slope = 1.
57).

b Cases with atrial fibrillation (total dose tracking time = 34.
7 seconds, mean slope = 0.
31).

This study shows that TTT derived from embolization tracking carotid CTA is an effective auxiliary index for detecting atrial fibrillation related to left ventricular diastolic dysfunction and LAP elevation, which provides a reference for early clinical detection of the existence of atrial fibrillation and early treatment
.

Original source:

Joon Hyuk Song,Dougho Park,Yong-Suk Jeong,et al.
Potential role of bolus-tracking data of carotid CT angiography for atrial fibrillation prediction.
DOI:10.
1007/s00330-022-09072-z