MDCT Evaluation After Closure of Atrial Septal Defect with an Amplatzer Septal Occluder

Radiographic Review of Current Therapeutic and Monitoring Devices in the Chest

Chest radiographs are obtained as a standard part of clinical care. Rapid advancements in medical technology have resulted in a myriad of new medical devices, and familiarity with their imaging appearance is a critical yet increasingly difficult endeavor. Many modern thoracic medical devices are new renditions of old designs and are often smaller than older versions. In addition, multiple device designs serving the same purpose may have varying morphologies and positions within the chest. The radiologist must be able to recognize and correctly identify the proper positioning of state-of-the-art medical devices and identify any potential complications that could impact patient care and management. To familiarize radiologists with the arsenal of newer thoracic medical devices, this review describes the indications, radiologic appearance, complications, and magnetic resonance imaging safety of each device. ^©RSNA, 2018.

Midterm results of percutaneous closure of very large atrial septal defects in children: role of multislice computed tomography

AIMS

The aim of this study was to assess the midterm results of percutaneous closure of very large atrial septal defects (ASD) in children with transthoracic echocardiography (TTE) and multislice computed tomography (MSCT).

METHODS AND RESULTS

Among 142 children who underwent percutaneous ASD closure with the AMPLATZER® Septal Occluder (ASO) (AGA Medical Corporation, Plymouth, MN, USA) during an eight year period, 51 patients with very large defects, were evaluated by TTE and MSCT after a period of at least two years following ASD closure. Median age at ASD closure was six years (range 4-10), with mean ASD size 20.9±2.9 mm. Median device size was 20 mm (range 15-26) and median device: septal length ratio 0.95 (range 0.8-1). Early complications included one transient complete atrioventricular block and one device embolisation. At a median follow-up of 55 months (range 25-92) all patients were clinically asymptomatic and had a normal ECG. TTE did not demonstrate device protrusion across the lumen of either the systemic or pulmonary veins. The mean device: septal length ratio had decreased from 0.96±0.05 to 0.8±0.02 (p<0.001). There was good correlation between the measure of atrial septum length by TTE and MSCT (r: 0.79, p<0.001). MSCT identified moderate dynamic device protrusion into the lumen of systemic or pulmonary veins in five patients and partial device malpositioning in two patients.

CONCLUSIONS

Occlusion of very large ASD in children can be performed with low complications rate. MSCT provides detailed information regarding the location of the device with respect to surrounding anatomic structures and reveals anomalies not evident by TTE.

Evaluation of image quality and radiation dose at prospective ECG-triggered axial 256-slice multi-detector CT in infants with congenital heart disease

BACKGROUND

There are a limited number of reports on the technical and clinical feasibility of prospective electrocardiogram (ECG)-gated multi-detector computed tomography (MDCT) in infants with congenital heart disease (CHD).

OBJECTIVE

To evaluate image quality and radiation dose at weight-based low-dose prospectively gated 256-slice MDCT angiography in infants with CHD.

MATERIALS AND METHODS

From November 2009 to February 2010, 64 consecutive infants with CHD referred for pre-operative or post-operative CT were included. All were scanned on a 256-slice MDCT system utilizing a low-dose protocol (80 kVp and 60-120 mAs depending on weight: 60 mAs for ≤ 3 kg, 80 mAs for 3.1-6 kg, 100 mAs for 6.1-10 kg, 120 mAs for 10.1-15 kg).

RESULTS

No serious adverse events were recorded. A total of 174 cardiac deformities, confirmed by surgery or heart catheterization, were studied. The sensitivity of MDCT for cardiac deformities was 97.1%; specificity, 99.4%; accuracy, 95.9%. The mean heart rate during scan was 136.7 ± 14.9/min (range, 91-160) with a corresponding heart rate variability of 2.8 ± 2.2/min (range, 0-8). Mean scan length was 115.3 ± 11.7 mm (range, 93.6-143.3). Mean volume CT dose index, mean dose-length product and effective dose were 2.1 ± 0.4 mGy (range, 1.5-2.8), 24.7 ± 5.9 mGy·cm (range, 14.7-35.8) and 1.6 ± 0.3 mSv (range, 1.1-2.5), respectively. Diagnostic-quality images were achieved in all cases. Satisfactory diagnostic quality for visualization of all/proximal/distal coronary artery segments was achieved in 88.4/98.8/80.0% of the scans.

CONCLUSION

Low-dose prospectively gated axial 256-slice CT angiography is a valuable tool in the routine clinical evaluation of infants with CHD, providing a comprehensive three-dimensional evaluation of the cardiac anatomy, including the coronary arteries.

Noninvasive imaging of prosthetic cardiac devices

The major advances in cardiovascular care can be linked to the combined growth of advanced imaging modalities and the variety of treatment options available for patients with complex structural, acquired and congenital, valvular, myocardial and aortic diseases. Paralleling this growth are the number and spectrum of complications - such as device failures and infections - that these patients will inevitably encounter. The keys to successful implementation of advanced cardiac therapy are the real-time images, 3D reconstructions, and the hemodynamic and tissue profiles that can be obtained to evaluate these patients and their devices. We will review the roles of echocardiography, multidetector computed tomography and MRI in the evaluation of normal and abnormal cardiac device function.

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.

State-of-the-art CT imaging techniques for congenital heart disease

CT is increasingly being used for evaluating the cardiovascular structures and airways in the patients with congenital heart disease. Multi-slice CT has traditionally been used for the evaluation of the extracardiac vascular and airway abnormalities because of its inherent high spatial resolution and excellent air-tissue contrast. Recent developments in CT technology primarily by reducing the cardiac motion and the radiation dose usage in congenital heart disease evaluation have helped expand the indications for CT usage. Tracheobronchomalacia associated with congenital heart disease can be evaluated with cine CT. Intravenous contrast injection should be tailored to unequivocally demonstrate cardiovascular abnormalities. Knowledge of the state-of-the-art CT imaging techniques that are used for evaluating congenital heart disease is helpful not only for planning and performing CT examinations, but also for interpreting and presenting the CT image findings that consequently guide the proper medical and surgical management.

Neonatal cardiac multidetector row CT: why and how we do it

Neonatal congenital heart disease is a most difficult area of diagnostic radiology because of the small patient body size and fast resting heart rate. Recently, the spatial and temporal resolution of multidetector-row CT (MDCT) has evolved so that neonatal congenital heart disease can be precisely diagnosed. We describe the role of MDCT in neonatal congenital heart disease and offer tips for the scanning procedure to familiarize radiologists with this developing field.

Multidetector computed tomography in the adolescent and young adult with congenital heart disease

As a result of improved postoperative management and transcatheter interventions, the number of adults with congenital heart disease in the United States has grown exponentially. Consequently, noninvasive imaging has taken an essential role in the evaluation of this patient population. Although standard noninvasive imaging tools such as transthoracic echocardiography and cardiovascular magnetic resonance may be invaluable to this group, occasionally there may be contraindications to their use or limitations in their utility. Multidetector computed tomography (MDCT) has only recently been used in the assessment of the adult with congenital heart disease. The ever-increasing availability of MDCT, along with its increased spatial and temporal resolution and rapidity of postprocessing, makes this an attractive first-choice to study this complex group. A successful scan requires familiarity with the complexity of the underlying anatomy and prior palliative or complete surgical repairs. It is with this knowledge in mind that MDCT provides exquisite detail of complex, 3-dimensional anatomic relations. This review illustrates the spectrum of MDCT findings in the adult with simple and complex forms of congenital heart disease.