Clinical application of 64-slice spiral CT in the diagnosis of the Tetralogy of Fallot

Surgical Treatment of Adults with Uncorrected Tetralogy of Fallot: A Clinical Case Series

The tetralogy of Fallot is the most common form of cyanotic congenital heart malformations. However, its association with Down syndrome is uncommon. We present two patients with uncorrected during childhood tetralogy of Fallot. One of them had also Down syndrome. We performed a complete surgical correction: closure of the inter-ventricular defect, right ventricular outflow tract reconstruction, pulmonary valve prosthesis and pulmonary artery patch repair (in one of the cases). The postoperative period was uncomplicated, patients were discharged on days 12 and 10, and the follow-up showed a significant functional class improvement.

Three steps approach for preoperative evaluation of tetralogy of Fallot patients: role of 128 MDCT

Background

Tetralogy of Fallot is the most common congenital cyanotic heart disease. Advances in surgical repair recently facilitate survival of the affected patients into adulthood with good quality of life. Despite imaging plays crucial role in diagnosis of TOF patients, no single diagnostic modality suffices for complete evaluation of TOF. Thus, different diagnostic tools should be used alone or in combination according to patient’s clinical question. This study aims to find out the agreement between the echocardiography and MDCT in evaluation of TOF patients prior to surgical repair.

Results

Three-step approach used in scanning TOF patients. Firstly, classic TOF findings, MDCT was comparable to echocardiography in overriding aorta (k = 0.6), VSD (k = 0.8), RVH (k = 0.4), and sub valvular pulmonary stenosis (k = 0.6). Echocardiography is superior to MDCT in evaluation of valvular stenosis (k = 0.4). MDCT was superior to echocardiography in supravalvular pulmonary stenosis. Secondary, surgical relevant findings, McGoon ratio calculated in 94.2%, small and major APCs in 45.5% and 28.5% respectively, PDA in 35% and anomalous coronary artery in 5.1%. Thirdly, other TOF-associated anomalies, common: ASD (34.3%) and RAA (28.3%), and persistent LSVC (10.3%). Uncommon: situs ambiguous (2.5 %), PAPVR (1.2%), and IVC anomalies (3.8%). MDCT was superior to echocardiography in surgical relevant findings and other TOF-associated anomalies.

Conclusion

MDCT is a crucial imaging tool for extra cardiac evaluation of TOF patients prior to surgical repair.

Stenting the complex patent ductus arteriosus in tetralogy of Fallot with pulmonary atresia: challenges and outcomes

Patent ductus arteriosus (PDA) stenting has gained acceptance for palliation in cyanotic congenital heart disease. The PDA in tetralogy of Fallot with pulmonary atresia (ToF-PA) arises, in the left aortic arch, from underneath the arch and connects to the proximal left pulmonary artery, often resulting in stenosis. The PDA is usually elongated and tortuous, making stent implantation challenging. Shorter duration of palliation, aggravation of branch pulmonary artery stenosis resulting in poor growth and difficulty at surgery makes ductal stenting controversial. Access via the carotid and axillary artery reduces complexity of the procedure and improves success, with recent data demonstrating good pulmonary artery growth. Advances in bioresorbable stents offer future promise and will likely resolve some controversies surrounding PDA stenting in ToF-PA.

Comparison of Echocardiography and 64-Multislice Spiral Computed Tomography for the Diagnosis of Pediatric Congenital Heart Disease

BACKGROUND The goals of this study were: to compare echocardiogram and 64-multislice spiral computed tomography (64-MSCT) in diagnosing pediatric congenital heart disease; to determine the significance of ECHO for diagnosing congenital heart disease; and to identify the appropriate diagnosis for congenital heart disease through combined use of 64-MSCT and ECHO. MATERIAL AND METHODS Thirty patients underwent both ECHO and 64-MSCT diagnoses before their surgeries. Imaging from ECHO and 64-MSCT were analyzed by 4 specialists. The diagnostic accuracy and kappa value of ECHO and 64-MSCT were evaluated based on the operation results. The accuracy of the 2 methods was evaluated using the McNemar χ² test. RESULTS We confirmed 138 malformations in 30 children by surgery. The diagnostic accuracy of ECHO and 64-MSCT was 98.40% and 96.20%, respectively, with a significant difference between the 2 results (χ²=6.404, P=0.011). We compared prognosis accuracy and uniformity on 3 types of congenital heart disease (cardiac malformation, heart-large vascular connecting malformation, and large vascular malformation): 56 cardiac malformations were confirmed by surgery, in which the diagnostic accuracy of ECHO and 64-MSCT was 99.50% and 94.80%, respectively. (χ²=8.578, P=0.034); 31 heart-large vascular connecting malformations were confirmed by surgery, in which the diagnostic accuracy of ECHO and 64-MSCT was 99.00% and 95.42% (χ²=6.779, P=0.009); and 51 vascular malformations were confirmed, in which the diagnostic accuracy of ECHO and 64-MSCT was 96.30% and 98.30% (χ²=1.806, P=0.179). CONCLUSIONS ECHO is more effective than 64-MSCT in preoperative diagnosis of congenital heart disease, especially for children.

Comparison of Image Quality, Diagnostic Accuracy and Radiation Dose Between Flash Model and Retrospective ECG-Triggered Protocols in Dual Source Computed Tomography (DSCT) in Congenital Heart Diseases

BACKGROUND

Dual source computed tomography (DSCT) plays an important role in the diagnosis of congenital heart diseases (CHD). However, the issue of radiation-related side effects constitutes a wide public concern. The aim of the study was to explore the differences in diagnostic accuracy, radiation dose and image quality between a prospectively ECG - triggered high - pitch spiral acquisition (flash model) and a retrospective ECG-gated protocol of DSCT used for the detection of CHD.

MATERIAL/METHODS

The study included 58 patients with CHD who underwent a DSCT examination, including two groups of 29 patients in each protocol. Then, both subjective and objective image quality, diagnostic accuracy and radiation dose were compared between the two protocols.

RESULTS

The image quality and the total as well as partial diagnostic accuracy did not differ significantly between the protocols. The radiation dose in the flash model was obviously lower than that in the retrospective model (P<0.05).

CONCLUSIONS

Compared to the retrospective protocol, the flash model can significantly reduce the dose of radiation, while maintaining both diagnostic accuracy and image quality.

Evaluation of High-Pitch Ungated Pediatric Cardiovascular Computed Tomography for the Assessment of Cardiac Structures in Neonates

PURPOSE

We evaluated a high-pitch, non-electrocardiogram-gated cardiac computed tomographic protocol, designed to image both cardiac and extracardiac structures, including coronary arteries, in a neonatal population (less than 1 year old) that was referred for congenital heart disease assessment and compared it with an optimized standard-pitch protocol in an equivalent cohort.

MATERIALS AND METHODS

Twenty-nine high-pitch scans were compared with 31 age-matched, sex-matched, and weight-matched standard-pitch, dosimetrically equivalent scans. The visualization and subjective quality of both cardiac and extracardiac structures were scored by consensus between 2 trained blinded observers. Image noise, signal-to-noise and contrast-to-noise ratios, and radiation doses were also compared.

RESULTS

The high-pitch protocol better demonstrated the pulmonary veins (P=0.03) and all coronary segments (all P<0.05), except the distal right coronary artery (P=0.10), with no significant difference in the visualization of the remaining cardiac or extracardiac structures. Both contrast-to-noise and signal-to-noise ratios improved due to greater vessel opacity, with significantly fewer streak (P<0.01) and motion (P<0.01) artifacts. Image noise and computed tomographic dose index were comparable across the 2 techniques; however, the high-pitch acquisition resulted in a small, but statistically significant, increase in dose-length product [13.0 mGy.cm (9.0 to 17.3) vs. 11.0 mGy.cm (9.0 to 13.0), P=0.05] due to greater z-overscanning.

CONCLUSIONS

In neonates, a high-pitch protocol improves coronary artery and pulmonary vein delineation compared with the standard-pitch protocol, allowing a more comprehensive assessment of cardiovascular anatomy while obviating the need for either patient sedation or heart rate control.

Variations of pulmonary arteries and other associated defects in Tetralogy of Fallot

BACKGROUND

The objective of study was to determine pulmonary artery variations and other associated cardiac defects in patients with Tetralogy of Fallot. This cross-sectional, descriptive study was carried out at The Children's Hospital and the Institute of Child Health, Lahore, from January 2006 to December 2012. All patients with Tetralogy of Fallot, who underwent cardiac catheterization during this period, were included. Standard cine-angiograms were done to record the pulmonary artery sizes and associated cardiac defects.

DESCRIPTION

A total of 576 patients with Tetralogy of Fallot were catheterized. Pulmonary Artery abnormalities were present in 109 (18.92%) patients. The commonest abnormality was isolated Left Pulmonary Artery stenosis (n = 60, 10.4%) followed by supra-valvular stenosis (n = 9, 1.6%). Left Pulmonary Artery was absent in seven patients(1.2%), while 1 patient (0.2%) had both absent right and left Pulmonary Arteries with segmental branch pulmonary arteries originating directly from Main Pulmonary Artery. Associated cardiac lesions included right aortic arch in 72 (12.5%), additional muscular Ventricular Septal Defect in 31 (5.4%), Patent Ductus Arteriosus in 31 (5.4%), bilateral Superior Vena Cava 36(6.2%), Atrial Septal Defect 4(0.7%) and Major Aortopulmonary Collateral Arteries in 75(13%) patients. Significant coronary artery abnormalities were present in 28(4.9%) children.

CONCLUSION

Pulmonary artery abnormalities were present in 18.92% of patients with Tetralogy of Fallot. Isolated Left Pulmonary Artery origin stenosis was the most common abnormality. Significant associated cardiac lesions including Patent Ductus Arteriosus , additional muscular Ventricular Septal Defect, coronary artery abnormalities, bilateral Superior Vena Cava, Atrial Septal Defect and Major Aortopulmonary Collateral Arteries were present in one-third of the patients.

Computed tomographic versus catheterization angiography in tetralogy of Fallot

AIM

To compare multidetector computed tomographic angiography with the gold standard cardiac catheterization and angiography in tetralogy of Fallot.

METHODS

In 40 consecutive patients over 5 years of age with tetralogy of Fallot, multidetector computed tomographic angiography and catheterization angiography studies were compared for intracardiac anatomy, pulmonary anatomy and indices, coronaries and collaterals. Safety parameters, relative advantages and limitations were also analyzed.

RESULTS

All catheterization studies required hospitalization whereas all tomographic studies were performed as outpatient procedures. The need for sedation and amount of contrast used were significantly greater in catheterization than in tomographic studies. Complications noted during catheterization were access site complications in 4 patients, cyanotic spells in 2, transient complete heart block requiring temporary pacing in 2, and air embolism in one. No complication was observed during tomographic studies. All tomographic studies were adequate, but 2 catheterization studies were inadequate. Ventricular septal defects, aortic override, level of right ventricular outflow tract obstruction, and pulmonary artery anatomy were equally assessed by both imaging modalities. However, tomographic studies missed additional small muscular ventricular septal defects. There was a linear correlation between tomographic and catheterization studies for pulmonary annulus size, artery sizes, Z-score, and Nakata index. There was complete concordance with respect to side of aortic arch and detection of collaterals. Coronary anatomy was better delineated in tomographic studies.

CONCLUSIONS

For preoperative evaluation of tetralogy of Fallot patients, multidetector computed tomographic angiography can be used as a reliable noninvasive alternative to cardiac catheterization angiography.

Low-dose prospectively electrocardiogram-gated axial dual-source CT angiography in patients with pulsatile bilateral bidirectional Glenn Shunt: an alternative noninvasive method for postoperative morphological estimation

OBJECTIVE

To explore the clinical value of low-dose prospectively electrocardiogram-gated axial dual-source CT angiography (low-dose PGA scanning, CTA) in patients with pulsatile bilateral bidirectional Glenn shunt (bBDG) as an alternative noninvasive method for postoperative morphological estimation.

METHODS

Twenty patients with pulsatile bBDG (mean age 4.2±1.6 years) underwent both low-dose PGA scanning and conventional cardiac angiography (CCA) for the morphological changes. The morphological evaluation included the anatomy of superior vena cava (SVC) and pulmonary artery (PA), the anastomotic location, thrombosis, aorto-pulmonary collateral circulation, pulmonary arteriovenous malformations, etc. Objective and subjective image quality was assessed. Bland-Altman analysis and linear regression analyses were used to evaluate the correlation on measurements between CTA and CCA. Effective radiation dose of both modalities was calculated.

RESULTS

The CT attenuation value of bilateral SVC and PA was higher than 300 HU. The average subjective image quality score was 4.05±0.69. The morphology of bilateral SVC and PA was displayed completely and intuitively by CTA images. There were 24 SVC above PA and 15 SVC beside PA. Thrombosis was found in 1 patient. Collateral vessels were detected in 13 patients. No pulmonary arteriovenous malformation was found in our study. A strong correlation (R2>0.8, P<0.001) was observed between the measurements on CTA images and on CCA images. Bland-Altman analysis demonstrated a systematic overestimation of the measurements by CTA (the mean value of bias>0).The mean effective dose of CTA and CCA was 0.50±0.17 mSv and 4.85±1.34 mSv respectively.

CONCLUSION

CT angiography with a low-dose PGA scanning is an accurate and reliable noninvasive examination in the assessment of morphological changes in patients with pulsatile bBDG.

Initial experience on the application of 320-row CT angiography with low-dose prospective ECG-triggered in children with congenital heart disease

To investigate the clinical significance of the application of 320-row CT angiography with low-dose prospective ECG-triggered target scanning in children with complex congenital heart disease (CHD), and to compare with the results from transthoracic echocardiography (TTE). 22 patients (male 12 cases, female 10 cases, average age: 18 months, range: 14 days-9 years, average weight: 13 kg) received an examination through 320-row CT angiography with low-dose prospective ECG-triggered volume target scan mode and transthoracic echocardiography. The center of phase window for data collection in this study was set to 40% of the R-R interval. Of these, 18 patients received surgery and 4 patients received conventional cardiac angiography (CCA). The diagnostic accuracy of 320-row CTA was calculated according to the examination results from surgical and/or cardiac angiography. The overall quality score for CTA images was divided into five levels. The results were compared with the research data of radiation doses obtained from patients with congenital heart disease who had received CT angiography. Complex congenital heart disease was confirmed by surgical or CCA in each of 22 patients, with 42 cases of large vascular malformations outside the heart cavity, and 26 of intracardiac malformations. The diagnostic accuracy of 320-row CT angiography and transthoracic echocardiography for large vascular malformation outside the heart cavity was 95.2 and 80.9%, respectively; for intracardiac malformation the accuracy was 88.5 and 100.0%, respectively. There was significant difference between 320-row CT and transthoracic echocardiography in the diagnosis of large vascular malformation outside the heart cavity (P < 0.05) with better results in 320-row CT, and no significant difference was found in the diagnosis of intracardiac malformation (P > 0.05). The average subjective image quality score was 4.4 ± 0.7 points. The average effective dose was 0.42 ± 0.08 mSv. 320-row CT enables direct visualization of the vascular configuration and shape of the aorta, pulmonary artery, and other large vessels to diagnose extracardiac vascular malformations. Combined with transthoracic echocardiography, 320-row CT is a promising technology that may be able to replace catheter based angiography to evaluate congenital cardiovascular malformations.

[Role of MSCT and MRI in the diagnosis of congenital heart disease]

Initial diagnosis of congenital heart disease traditionally relies upon clinical examination and ultrasound. Development of non-invasive imaging, multislice CT (MSCT) and magnetic resonance imaging (MRI) has changed the way those patients are evaluated for diagnosis or follow-up. Cardiac catheterization is no longer the step two and in many clinical situations, non-invasive imaging is the method of choice, either before or instead of invasive angiography examination. Cross-sectional cardiovascular imaging brings thorough examination of the thorax, heart and great vessels, leading to three-dimensional volumes imaging, allowing diagnosis of the cardiopathy, evaluation of the anatomy and associated abnormalities. For each imaging technique advantages and drawbacks are discussed. X-ray use is the main disadvantage of MSCT, although it is a fast, easy and efficient technique, especially in babies because of its high spatial and temporal resolutions. Beside a precise 3D evaluation of the heart and great vessels, MSCT allows evaluation of small structures, like coronary arteries in routine, including in neonates and infants, at a fast cardiac rhythm, and in a short examination time. The air-filled structures are well-depicted with MSCT, and 3D imaging is helpful in evaluation of tracheal and bronchi compression as compared to MRI. MR imaging brings, aside from the morphologic evaluation, helpful functional information for the left and right ventricles, and evaluation of valvular disease (stenosis and regurgitation). Those are critical data in the follow-up of patients treated for tetralogy of fallot or after atrial switch for transposition of the great vessels. The technique is also very powerful in evaluating aortic disease, e.g. aortic coarctation and restenosis, and Marfan's disease. Disadvantages are mainly the accessibility and the examination time, which in young patients may require sedation or general anaesthesia. Cross-sectional cardiovascular imaging, MSCT and MRI, have considerably changed the diagnosis and follow-up of patients suffering of congenital cardiopathy. The techniques are complementary, and the choice will depend on the age, the clinical condition and the diagnosis of the patient.

Safety and efficacy of a drug regimen to control heart rate during 64-slice ECG-gated coronary CTA in children

BACKGROUND

The adult practice for ECG-gated single-source 64-slice coronary CTA (CCTA) includes administering beta-blockers to reduce heart rate. There are limited data on this process in children.

OBJECTIVE

To evaluate the safety and efficacy of a drug regimen to decrease heart rate before performing CCTA in children.

MATERIALS & METHODS

IV remifentanil and esmolol infusion were chosen to decrease heart rate in 41 children (mean age 6.5 years) while they were under general anesthesia (GA) for CCTA. Drug doses, changes in heart rate and procedural complications were recorded. CCTA image quality was graded on a scale of 1 to 5. The relationships between image quality and heart rate and image quality and age were evaluated. Patient effective radiation doses were calculated.

RESULTS

Heart rates were lowered utilizing esmolol (4 children), remifentanil (2 children) or both (35 children); 26 children received nitroglycerin for coronary vasodilation. The mean decrease in heart rate was 26%. There were no major complications. The average image-quality score was 4.4. Higher heart rates were associated with worse image quality (r = 0.67, P < 0.0001). Older age was associated with better image quality (r = 0.66, P < 0.0001). Effective radiation doses were 0.7 to 7.0 mSv.

CONCLUSION

Heart rate reduction for pediatric CCTA can be safely and effectively achieved while yielding high-quality images.

[Congenital heart disease in adults: the contribution of multidetector CT]

Congenital heart disease is relatively common among adults. Patients' conditions have generally been diagnosed previously and imaging tests are requested for follow-up or for complications of the anomaly or of its surgical correction. Classically, these patients were studied with echocardiography and cardiac catheterization, but multidetector CT and magnetic resonance imaging have changed the approach because these techniques show the anatomy of heart defects and their correction very clearly. We emphasize the importance of multidetector CT as a complementary technique for the study of congenital heart disease that is newly discovered in adults or for the follow-up of congenital heart disease that was surgically corrected during childhood. When vascular anomalies are present outside the heart or after palliative surgery, multidetector CT shows anatomical details that are difficult or impossible to see with echocardiography. We also emphasize the frequent association between pulmonary hypertension and congenital heart disease that can debut in adults.

Assessment of tumor recurrence in patients with colorectal cancer and elevated carcinoembryonic antigen level: FDG PET/CT versus contrast-enhanced 64-MDCT of the chest and abdomen

OBJECTIVE

The purpose of this study was to compare FDG PET/CT and contrast-enhanced 64-MDCT of the chest, abdomen, and pelvis in the detection of tumor recurrence in patients with colorectal cancer and an elevated level of carcinoembryonic antigen (CEA).

MATERIALS AND METHODS

A retrospective analysis included 50 patients (31 men, 19 women; mean age, 61 years; range, 28-89 years) with 55 clinical events of elevated or increasing CEA level who underwent FDG PET/CT and MDCT for suspected tumor recurrence.

RESULTS

Recurrent or metastatic disease was found in 36 of 55 events (65.5%) of elevated CEA. Fifty-four of 61 tumor sites suspected as tumor recurrence with any imaging technique were found to be local recurrence or metastatic colorectal cancer at final analysis. The other seven sites were one separate malignant tumor (small lymphocytic lymphoma) and six benign lesions. Diagnosis was based on histopathologic findings (n = 27) or clinical and imaging findings (n = 35) during a median follow-up period of 12 months (range, 6-31 months). One site of tumor recurrence was missed prospectively at both MDCT and PET/CT. On an event-based analysis, the sensitivity of PET/CT and MDCT was 97.3% and 70.3% (p = 0.002); the specificity of both techniques was 94.4% (p = 1.0). In a tumor site-based analysis, the sensitivities of PET/CT and MDCT were 98.1% and 66.7% (p < 0.0001), and the specificities were 75% and 62.5% (p = 0.56). Tumors correctly identified with PET/CT and missed with MDCT were local recurrence in the presacral space (n = 5), metastatic subcentimeter lymph nodes (n = 4), peritoneal deposits (n = 3), and recurrences at the periphery of radiofrequency ablated metastatic lesions of the liver (n = 2) and in the abdominal wall (n = 1), liver (n = 1), and uterine cervix (n = 1).

CONCLUSION

FDG PET/CT has higher sensitivity than MDCT in the identification of sites of recurrent and metastatic disease in patients with colorectal cancer and an elevated CEA level. The two techniques appear to have similar specificity.

CT evaluation of congenital heart disease in adults

OBJECTIVE

The purpose of this article is to describe the spectrum of imaging findings of congenital heart disease in adults.

CONCLUSION

Continued advances in CT have facilitated evaluation of two important patient populations: adults with surgically palliated congenital heart disease and adults with previously undiagnosed congenital heart disease.

Uncorrected pink tetralogy of Fallot in an adult patient: incidental CT findings

Tetralogy of Fallot (TOF), one of the most common congenital heart diseases, has four major components: right ventricular hypertrophy, overriding aorta, membranous ventricular septal defect, and right ventricular outflow tract obstruction. If not already present at birth, cyanosis develops in the first year of life. Survival of the patient depends on the degree of pulmonary obstruction and the pulmonary blood supply. Patients rarely survive after the fourth decade of life. Limitation of blood to the lungs combined with ventricular septal defect results in supply of oxygen-poor blood to the body, causing cyanosis (blue coloration) in the patient. If the pulmonary stenosis is mild and ventricular septal defect is in balance, however, the noncyanotic patient is referred as having "pink tetralogy of Fallot."

Assessment of urinary tract calculi with 64-MDCT: The axial versus coronal plane

OBJECTIVE

The objective of our study was to compare the detection rate, conspicuity, and size measurements of urinary tract calculi on coronal reformations versus the axial plane using 64-MDCT.

MATERIALS AND METHODS

For this retrospective study, 80 consecutive CT examinations performed for clinical diagnosis of renal colic or for the assessment of known nephrolithiasis were evaluated. All studies were stripped of patient identifiers, and the axial and coronal plane images of each study were randomized and presented to two abdominal radiologists. For each study, the radiologists recorded the number and location of stones, diagnostic confidence and stone conspicuity (subjectively on a 2-point scale), and stone size. The standard of reference was data from a consensus reading with the study coordinator examining the same parameters on images in both planes of each patient. Detection rates were compared between planes using logistic regression with generalized estimating equations to account for multiple stones per patient.

RESULTS

On consensus reading, 272 stones were identified. For all renal stones, the coronal plane detected more stones as compared with the axial plane (p < 0.001). For stones smaller than 5 mm, a higher proportion received the maximal conspicuity score on the coronal plane than on the axial plane (p < 0.001). Both reviewers better estimated stone size on the coronal plane than the axial plane (p = 0.02); their axial plane measurements underestimated stone size by 13.4% (mean).

CONCLUSION

The detection of stones and estimation of maximal stone diameter were improved using coronal reformations. The conspicuity of stones and diagnostic confidence in identifying stones smaller than 5 mm in diameter were also improved on the coronal plane.