Factors associated with left atrial appendage filling defects on early-phase cardiac computed tomography in patients with nonvalvular atrial fibrillation: a case-control study

Figures

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  Figure 1. Flowchart of patient enrollment. AF, atrial fibrillation; CCT, cardiac computed tomography; LAA, left atrial appendage; TEE, transesophageal echocardiography; TTE, transthoracic echocardiography; ECG, electrocardiogram.

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  Figure 2. Measurement of LAAFV by TEE and definition of the LAA filling defects on early-phase CCT. (A,B) During TEE, LAAFV was measured by pulse Doppler ultrasound. Representative images are shown for a patient in the early filling defect group (LAAFV 24 cm/s; A) and another patient in the control group (LAAFV 70 cm/s; B). (C,D) CCT of another patient showed an LAA filling defect in the early phase (C) and no filling defect in the corresponding position in the delayed phase (D). LAAFV, left atrial appendage flow velocity; TEE, transesophageal echocardiography; LAA, left atrial appendage; CCT, cardiac computed tomography.

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  Figure 3. (A-C) Classification of the severity of the early filling defect in the LAA and (D,E) measurement, in HU, of the LAA and AA. (A) Normal filling: contrast enhancement of the LAA cavity (arrow) is equal to or higher than that of LA cavity. (B) Mild to moderate filling defect: contrast enhancement of the LAA cavity (arrow) is lower than that of the LA cavity, but the contrast between the pectinate muscle and LAA cavity is good. (C) Severe filling defect: contrast enhancement of the LAA cavity (arrow) is lower than that of the LA cavity, with no contrast between the pectinate muscle and LAA cavity (arrow). (D) Regions of interest (~10 mm2) were placed inside the filling defect in the LAA seen on early CCT images and the AA on the same slice to generate an LAA/AA HU ratio. (E) LAA HU on delayed CCT images was measured in the same way to generate the LAAe–LAAd. LAA, left atrial appendage; HU, Hounsfield units; AA, ascending aorta; LA, left atrium; LAAe–LAAd, HU difference between early and delayed CCT of the LAA. CCT, cardiac computed tomography.

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  Figure 4. Measurement methods for the LAA orifice, LSPV orifice, and LAA ridge width. (A) The center of the cross-positioning line was placed in the transition area between the LA and LAA, with the 2 positioning lines parallel and vertical to the LAA length. (B-D) On oblique coronal images of the LAA, the cross-positioning line was adjusted at the atrial wall fold in the oblique coronal image transition area, with the 2 positioning lines made parallel and vertical to the LAA (B) to obtain an image of the LAA orifice to measure the orifice area (C) and the long and short diameters (D). (E) The same multiplanar reconstruction method was used to obtain the orifice section of the LSPV for measurement. (F) The width of the middle of the LAA ridge was measured by virtual endoscopy. LAA, left atrial appendage; LSPV, left superior pulmonary vein; LA, left atrium.

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  Figure 5. Measurement of the volume and depth of the LAA using cardiac function analysis software. (A) The 3D image and volume of the LA were obtained automatically. (B-D) The filling tool was used to fill in the LAA on the axial image (B,C) to obtain the 3D image (D) of the LA and LAA. (E,F) The cutting tool was used to separate the LA and LAA from the LAA orifice to obtain the LAA volume (E) and to measure the depth of the LAA along its direction (F). LAA, left atrial appendage; 3D, 3-dimensional; LA, left atrium.

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  Figure 6. (A-D) Morphology and (E-G) location of the LAA. (A) Chicken wing, (B) cauliflower, (C) cactus, and (D) windsock morphology. (E-G) Classification of LAA location was based on the relationship between the LAA and LSPV. LAA location was classified as either type I (E; the LAA is higher than the LSPV), type II (F; the LAA and LSPV are at the same level), or type III (G; the LAA is lower than the LSPV). LAA, left atrial appendage; LSPV, left superior pulmonary vein.

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  Figure 7. ROC curve analysis of the early filling defect in the LAA, relationships between LAAFV and the LAA/AA HU ratio or the LAAe–LAAd, and box plots of LAAFV according to the severity of the LAA filling defect. (A) Using ROC curve analysis, a cutoff value for LAAFV of 40.5 cm/s was established, which had an AUC of 0.905 (sensitivity 82.4%, specificity 91.2%). (B) Using ROC curve analysis, a cutoff value for the left atrium volume index of 58.77 mL/m2 was established, which had an AUC of 0.840 (sensitivity 85.3%, specificity 72.1%). (C,D) Significant positive correlations were found between LAAFV and both the LAA/AA HU ratio of early-phase CCT (C; r=0.614; P<0.001) and LAAe–LAAd (D; r=0.591; P<0.001). (E) Significant (P<0.05) differences were detected in LAAFV according to the severity of the LAA filling defect (no defect: median 56 cm/s, IQR 44–75 cm/s; mild to moderate filling defect: median 28 cm/s, IQR 23–34 cm/s; severe filling defect: median 21 cm/s, IQR 19–25 cm/s). The boxes show the IQR, with the median value indicated by the horizontal line; whiskers show the range. ROC, receiver operating characteristic; LAA, left atrial appendage; LAAFV, left atrial appendage flow velocity;…