Direction, location, and size of shunt flow in congenital heart disease evaluated by ECG-gated multislice computed tomography

The role of cardiac CT throughout the full cardiac cycle in diagnosing patent foramen ovale in patients with acute stroke

OBJECTIVES

We explored the hypothesis that the diagnostic performance of cardiac computed tomography (CT) throughout the full cardiac cycle would be superior to single-phase CT and comparable to transesophageal echocardiography (TEE) in diagnosing patent foramen ovale (PFO).

METHODS AND RESULTS

From May 2011 to April 2015, 978 patients with stroke were diagnosed with PFO by TEE. In patients with stroke, cardiac CT was performed if the patients had more than two cardiovascular risk factors. We prospectively enrolled 70 patients with an indication for cardiac CT. Cardiac CT images were reconstructed at 10% increments of the R-R interval. The sensitivity of cardiac CT throughout the full cardiac cycle in diagnosing PFO was compared to that for TEE and single-phase cardiac CT. To evaluate the specificity of cardiac CT, we analyzed patients without PFO confirmed by TEE who underwent cardiac CT within 1 month of pre-cardiac surgery. Sixty-six patients with cardiac CT and TEE were included in the final analysis. Throughout the full cardiac cycle, cardiac CT had a sensitivity of 89.4% and a specificity of 92.3% in diagnosing PFO, compared to TEE as a reference. PFO was primarily detected in the 60% and 70% intervals in 10-phase reconstructed images. The sensitivity of PFO diagnosis with cardiac CT was 81.8% when analyzing both the 60% and 70% intervals instead of the full cardiac cycle.

CONCLUSION

Cardiac CT throughout the full cardiac cycle outperforms single-phase cardiac CT in detecting PFO. Cardiac CT can be used as an alternative method to TEE for detecting PFO in stroke patients.

KEY POINTS

• Throughout the full cardiac cycle, cardiac computed tomography (CT) had a sensitivity of 89.4% and a specificity of 92.3% in diagnosing patent foramen ovale (PFO), compared to transesophageal echocardiography. • The sensitivity of diagnosing patent foramen ovale with cardiac CT was 81.8% when analyzing 60% and 70% R-R intervals instead of the full cardiac cycle. • Cardiac CT with retrospective electrocardiographic gating throughout the full cardiac cycle can increase the detectability of PFO, compared to single-phase cardiac CT.

Haemodynamic findings on cardiac CT in children with congenital heart disease

In patients with congenital heart disease, haemodynamic findings demonstrated on cardiac CT might provide useful hints for understanding the haemodynamics of cardiac defects. In contrast to morphological features depicted on cardiac CT, such haemodynamic findings on cardiac CT have not been comprehensively reviewed in patients with congenital heart disease. This article describes normal haemodynamic phenomena of cardiovascular structures and various abnormal haemodynamic findings with their mechanisms and clinical significance on cardiac CT in patients with congenital heart disease.

Amplatzer septal occluder closure of atrial septal defect: evaluation of transthoracic echocardiography, cardiac CT, and transesophageal echocardiography

OBJECTIVE

The purpose of this study was to compare transthoracic echocardiography (TTE), cardiac CT, and transesophageal echocardiography (TEE) in the evaluation of secundum atrial septal defect (ASD) for closure with an Amplatzer septal occluder in pediatric patients.

SUBJECTS AND METHODS

The cases of 28 children with ASD initially diagnosed with TTE who were scheduled for cardiac CT for evaluation for insertion of an Amplatzer septal occluder under TEE guidance were reviewed. The patients were divided into a group with small ASD (long axis < 1.5 cm) and a group with large ASD (long axis > or = 1.5 cm). Measurements of the ASD obtained at TTE, cardiac CT, and TEE were compared. Kappa statistics were used to correlate the diagnostic value of cardiac CT assessed by two independent reviewers.

RESULTS

After cardiac CT, six patients were excluded from occluder implantation; therefore, 22 patients (seven boys, 15 girls; mean age, 4.95 years; range, 2-11 years) were included in the study. There were no significant differences in the ages and sexes of the patients in the two groups, but pulmonary-to-systemic blood flow ratio in the large-ASD group was significantly greater than that in the small-ASD group (3.54 +/- 1.43 vs 1.89 +/- 0.36; p = 0.001). With respect to long- and short-axis lengths of the ASD, interatrial septum, and four rims and to detection of rim deficiency, neither group had a significant difference between cardiac CT findings at ventricular end-systole and TEE findings. The long axis of the ASD in the large-ASD group measured at cardiac CT at end-systole and TEE was significantly longer than the long axis measured at TTE (p = 0.012). A high diagnostic score with good interobserver correlation (kappa = 0.674-0.750) validated the feasibility of cardiac CT in the assessment of ASD for closure with an Amplatzer septal occluder.

CONCLUSION

The long axis of a large ASD can be underestimated at TTE. Cardiac CT seems comparable with TEE in the assessment of ASD and is helpful in noninvasive evaluation for Amplatzer septal occluder implantation, especially for large ASD.

Interatrial shunt detected in coronary computed tomography angiography: differential features of a patent foramen ovale and an atrial septal defect

OBJECTIVE

To determine differential findings of patent foramen ovales (PFOs) and atrial septal defects (ASDs) demonstrating interatrial shunting on coronary computed tomography (CT) angiography.

METHODS

We retrospectively analyzed 15 cases of patients demonstrating a contrast jet from the left to the right atrium on CT and interatrial shunting on echocardiography. According to the echocardiography results, patients were divided into PFO (n = 10) or ASD (n = 5) groups. The contrast jet direction and atrial septum appearance on CT were compared between the 2 groups.

RESULTS

The PFO group had a contrast jet flowing toward the inferior vena cava, and the atrial septum appeared channel-like. The ASD group had a contrast jet flowing perpendicular to the atrial septum in all but one of the patients, and the atrial septum appeared as a membrane with a hole.

CONCLUSIONS

Atrial septal defects and PFOs can be differentiated using the characteristic direction of the contrast jet from the left to right atrium and the appearance of the atrial septum on coronary CT angiography.

Gradual Pulmonary Artery Enhancement: New Sign of Septal Defects on CT

OBJECTIVE

Hemodynamic information observed on serial images obtained with bolus tracking might help in diagnosing septal defects on CT. Our purpose was to qualitatively and quantitatively examine a new sign called gradual pulmonary artery enhancement.

CONCLUSION

Gradual pulmonary artery enhancement is a newly recognized CT sign that may be helpful in evaluating septal defects.

Multislice Computed Tomography Accurately Quantifies Left Atrial Size and Function After the MAZE Procedure

Background— Although the MAZE procedure allows for the recovery of sinus rhythm and left atrial (LA) mechanical function in the great majority of patients with chronic atrial fibrillation (AF), the effects of MAZE on the precise LA geometry and wall motion remain to be elucidated. We hypothesized that LA size and mechanical function in patients with chronic AF and mitral valvular disease are well restored after MAZE.

Methods and Results— We studied 14 patients (MAZE group: mean±SD age, 63.9±8.6 years; 8 men and 6 women) who underwent MAZE for chronic AF and mitral valve surgery and 10 patients with sinus rhythm (coronary artery bypass graft [CABG] group: age, 70.0±7.9 years; 5 men and 5 women) who underwent CABG at Takeda Hospital between February 2002 and September 2005. MAZE was conducted by the endocardial application of radiofrequency ablation with a temperature-controlled multipolar radiofrequency catheter. LA volume and booster function were quantitatively evaluated by multislice computed tomography at 17.9±10.0 months (MAZE group) and 15.3±13.6 months (CABG group) postoperatively. All patients with MAZE were free of AF and other atrial arrhythmias during the follow-up period. In the CABG group, LA maximal and minimal volumes and ejection fraction were 109±12 mL, 82±11 mL, and 26±10%, respectively. In the MAZE group, LA maximal volume was 139±17 mL ( P =0.187 versus CABG), and LA minimal volume was 121±16 mL ( P =0.082 versus CABG), with an ejection fraction of 15±7% ( P =0.004 versus CABG). In both groups, all parts of the LA wall contracted toward the geometric center of the LA. The extent of wall motion was significantly worse in the MAZE group compared with the CABG group. In both groups, LA booster function was inversely correlated with LA maximal volume.

Conclusions— MAZE with radiofrequency ablation is safe and effective for the restoration of sinus rhythm in patients with chronic AF and mitral valve disease. However, chronic AF associated with mitral valve disease deteriorates LA mechanical function diffusely throughout the LA wall. Further studies with the use of multislice computed tomography are needed to sequentially evaluate LA function after MAZE in patients with and without mitral valve surgery.