Cardiac Computed Tomography of Native Cardiac Valves

Valvular heart disease (VHD) is a significant clinical problem associated with high morbidity and mortality. Although not being the primary imaging modality in VHD, cardiac computed tomography (CCT) provides relevant information about its morphology, function, severity grading, and adverse cardiac remodeling assessment. Aortic valve calcification quantification is necessary for grading severity in cases of low-flow/low-gradient aortic stenosis. Moreover, CCT details significant information necessary for adequate percutaneous treatment planning. CCT may help to detail the etiology of VHD as well as to depict other less frequent causes of valvular disease, such as infective endocarditis, valvular neoplasms, or other cardiac pseudomasses.

Mild aortic insufficiency following transcatheter aortic valve replacement: A systematic review and meta-analysis

BACKGROUND

Post-procedural aortic insufficiency (AI) continues to be prevalent following transcatheter aortic valve replacement (TAVR). While several studies have assessed the outcomes of moderate-severe AI following TAVR, the incidence, predictors, and outcomes of mild AI remain unclear.

METHODS

A systematic literature review was performed to identify studies reporting on mild AI following TAVR. The primary outcome was pooled incidence of post-TAVR mild AI. Secondary outcomes included pooled incidence of mild AI at 30 days and long term. The pooled incidence of midterm mortality in patients with post-TAVR mild AI was also evaluated. The random effect generalized linear mixed-effects model with logit-transformed proportions and Hartung-Knapp adjustment was used to calculate pooled incidence rates. Meta-regression was performed to identify predictors of mild AI.

RESULTS

The pooled analysis included 19,241 patients undergoing TAVR across 50 studies. The mean age of patients ranged from 73 to 85 years, and female patients ranged from 20.0% to 83.3%. The overall pooled incidence of post-TAVR mild AI was 56.1% (95% confidence interval [CI] 0.31-0.64). The pooled incidence of mild AI at 30 days was 33.7% (95% CI 0.12-0.37). At mean follow-up of 1.15 years, the pooled incidence of mild AI was 37.0% (95% CI 0.16-0.45). The overall pooled incidence of Midterm mortality (mean follow-up 1.22 years) in patients with mild AI was 14.8% (95% CI 0.10-0.25). At meta-regression, none of the explored variables correlated with a difference in mild AI incidence.

CONCLUSIONS

In published studies to date, 50% of patients undergoing TAVR develop mild AI postoperatively. In 37% of patients, this persists in long term. Though the incidence of AI is likely improving with newer generation TAVR valves, the prevalence and outcomes of mild AI should be closely monitored as TAVR volume and indications expand to younger patients with long life expectancy. The long-term outcomes of mild AI remain unclear. Further dedicated studies on post-TAVR mild AI are needed.

Computed Tomographic Evaluation of Congenital Left Ventricular Outflow Obstruction

Congenital left ventricular outflow obstruction represents a multilevel obstruction with several morphological forms. It can involve the subvalvular, valvar, or supravalvular portion of the aortic valve complex, and may coexist. Computed tomography (CT) plays an important supplementary role in the evaluation of patients with congenital LVOT obstruction. Unlike transthoracic echocardiography and cardiovascular magnetic resonance (CMR) imaging, it is not bounded by a small acoustic window, needs for anaesthesia or sedation, and metallic devices. Current generations of CT scanners with excellent spatial and temporal resolution, high pitch scanning, wide detector system, dose reduction algorithms, and advanced 3-dimensional postprocessing techniques provide a high-quality alternative to CMR or diagnostic cardiac catheterization. Radiologists performing CT in young children should be familiar with the advantages and disadvantages of CT and with the typical morphological imaging features of congenital left ventricular outflow obstruction.

Multimodality Evaluation of Aortic Insufficiency and Aortitis in Rheumatologic Diseases

Aortic insufficiency is commonly observed in rheumatologic diseases such as ankylosing spondylitis, systemic lupus erythematosus, antiphospholipid syndrome, Behçet's disease, granulomatosis with polyangiitis, and Takayasu arteritis. Aortic insufficiency with an underlying rheumatologic disease may be caused by a primary valve pathology (leaflet destruction, prolapse or restriction), annular dilatation due to associated aortitis or a combination of both. Early recognition of characteristic valve and aorta morphology on cardiac imaging has both diagnostic and prognostic importance. Currently, echocardiography remains the primary diagnostic tool for aortic insufficiency. Complementary use of computed tomography, cardiac magnetic resonance imaging and positron emission tomography in these systemic conditions may augment the assessment of underlying mechanism, disease severity and identification of relevant non-valvular/extracardiac pathology. We aim to review common rheumatologic diseases associated with aortic insufficiency and describe their imaging findings that have been reported in the literature.

Non coronary applications of cardiac computed tomography: A review

Acquired heart diseases including valvular pathologies and conduction abnormalities, along with coronary artery disease make cardiovascular disease one of the major causes of mortality and morbidity worldwide. Advances in cardiac computed tomography (CCT) have led to markedly improved image quality for assessment of several coronary and noncoronary cardiac abnormalities. With the latest versions of CT scanners, image acquisition can be completed within a few seconds, in a single breath hold and with much less radiation exposure, thus making CT an even more attractive diagnostic tool with its high temporal and excellent spatial resolution. Additional advantages are its noninvasive nature, wide availability, fast image acquisition and ability to provide additional data about the cardiac structure, function, valvular motion, and presence or absence of valvular vegetation, mass or intracardiac thrombus. These factors can result in change in management in many valvular pathologies pre- and post-intervention, and in electrophysiological procedures. The goal of this article is to review applications of cardiac CT in non-coronary indications including valvular assessment, pulmonary vein isolation procedure, and left atrial appendage evaluation for its transcatheter occlusion.

Computed Tomography of Cardiac Valves: Review

Valvular heart disease is a common clinical problem. Although echocardiography is the standard technique for the noninvasive evaluation of the valves, cardiac CT has evolved to become a useful tool in the evaluation of the cardiac structures as well. Importantly, CT allows for improved quantification of valvular calcification due to its superior spatial resolution. It may improve the detection of small valvular or perivalvular pathology or the characterization of valvular masses and vegetations. This review describes the assessment of normal and diseased heart valves by cardiac CT and discusses its strengths and weaknesses.

Interventricular membranous septal aneurysm: CT and MR manifestations

Advanced cardiac imaging is a valuable method to investigate cardiac malformations. The detection of the interventricular membranous septum has clinical significance due to thrombogenic and arrythmogenic predisposition, as well as a role in obstructing the pulmonary flow. This review describes six clinical presentations in which advanced cardiac imaging has been the tool for evaluation, with special emphasis in CT angiography and cardiac MRI sequences.

Teaching Points

• The interventricular membranous septum can predispose patients to thrombogenic and arrythmogenic events.

• Subpulmonic stenosis relates to the protrusion of the aneurysm into the right ventricle

• During surgery, ventricular pressures of the opened heart become balanced, making the aneurysm less evident.

Imaging of the right heart--CT and CMR

Right ventricular (RV) structure and function is of substantial importance in a broad variety of clinical conditions. Cardiac magnetic resonance (CMR) and computed tomography (CT) each provide three-dimensional RV imaging, high-resolution evaluation of RV structure/anatomy, and accurate functional assessment without geometric assumptions. This is of particular significance for the RV, where complex geometry compromises reliance on indices derived from two-dimensional (2D) imaging planes. CMR flow-based imaging can be applied to right-sided heart valves, enabling evaluation of hemodynamic and valvular dysfunction that may contribute to or result from RV dysfunction. Tissue characterization imaging by both CMR and CT provides valuable complementary assessment of the RV. Changes in myocardial tissue composition provide a mechanistic substrate for RV dysfunction and cardiac arrhythmias. This review provides an overview of RV imaging by both CMR and CT, with focus on assessment of RV structure/function, flow, and tissue characterization. Emerging evidence and established guidelines are discussed in the context of imaging contributions to diagnosis, prognostic risk stratification and disease management of clinical conditions that impact the right ventricle.

Multimodality imaging of heart valve disease

Unidentified heart valve disease is associated with a significant morbidity and mortality. It has therefore become important to accurately identify, assess and monitor patients with this condition in order that appropriate and timely intervention can occur. Although echocardiography has emerged as the predominant imaging modality for this purpose, recent advances in cardiac magnetic resonance and cardiac computed tomography indicate that they may have an important contribution to make. The current review describes the assessment of regurgitant and stenotic heart valves by multimodality imaging (echocardiography, cardiac computed tomography and cardiac magnetic resonance) and discusses their relative strengths and weaknesses.

Expert consensus for multi-modality imaging evaluation of cardiovascular complications of radiotherapy in adults: a report from the European Association of Cardiovascular Imaging and the American Society of Echocardiography

Cardiac toxicity is one of the most concerning side effects of anti-cancer therapy. The gain in life expectancy obtained with anti-cancer therapy can be compromised by increased morbidity and mortality associated with its cardiac complications. While radiosensitivity of the heart was initially recognized only in the early 1970s, the heart is regarded in the current era as one of the most critical dose-limiting organs in radiotherapy. Several clinical studies have identified adverse clinical consequences of radiation-induced heart disease (RIHD) on the outcome of long-term cancer survivors. A comprehensive review of potential cardiac complications related to radiotherapy is warranted. An evidence-based review of several imaging approaches used to detect, evaluate, and monitor RIHD is discussed. Recommendations for the early identification and monitoring of cardiovascular complications of radiotherapy by cardiac imaging are also proposed.

Imaging of cardiac valves by computed tomography

This paper describes "how to" examine cardiac valves with computed tomography, the normal, diseased valves, and prosthetic valves. A review of current scientific literature is provided. Firstly, technical basics, "how to" perform and optimize a multislice CT scan and "how to" interpret valves on CT images are outlined. Then, diagnostic imaging of the entire spectrum of specific valvular disease by CT, including prosthetic heart valves, is highlighted. The last part gives a guide "how to" use CT for planning of transcatheter aortic valve implantation (TAVI), an emerging effective treatment option for patients with severe aortic stenosis. A special focus is placed on clinical applications of cardiac CT in the context of valvular disease.

The Role of Cardiovascular Magnetic Resonance (CMR) and Computed Tomography (CCT) in Facilitating Heart Failure Management

OPINION STATEMENT

Cardiovascular magnetic resonance (CMR) and cardiac computed tomography (CCT) offer advantages for detecting left or right ventricular dysfunction in patients with or suspected of heart failure. CMR does not expose patients to ionizing radiation, and thus is well-suited for functional assessments and serial studies. CCT provides high spatial resolution, making it useful for the identification of coronary arteriosclerosis associated with ischemic cardiomyopathy. In this review, the clinical applications of CMR and CCT are individually discussed, with comparisons made between them to examine the strengths of each modality. The major techniques for each modality are outlined, as well as their uses for the evaluation of cardiomyopathy in heart failure patients with reduced left ventricular ejection fraction, preserved left ventricular ejection fraction, and valvular heart disease. Finally, we review the utility of CMR and CCT in determining which patients will benefit from cardiac resynchronization therapy.

CT and MR imaging of the aortic valve: radiologic-pathologic correlation

Valvular disease is estimated to account for as many as 20% of cardiac surgical procedures performed in the United States. It may be congenital in origin or secondary to another disease process. One congenital anomaly, bicuspid aortic valve, is associated with increased incidence of stenosis, regurgitation, endocarditis, and aneurysmal dilatation of the aorta. A bicuspid valve has two cusps instead of the normal three; resultant fusion or poor excursion of the valve leaflets may lead to aortic stenosis, the presence of which is signaled by dephasing jets on magnetic resonance (MR) images. Surgery is generally recommended for patients with severe stenosis who are symptomatic or who have significant ventricular dysfunction; transcatheter aortic valve implantation (TAVI) is an emerging therapeutic option for patients who are not eligible for surgical treatment. Computed tomography (CT) is an essential component of preoperative planning for TAVI; it is used to determine the aortic root dimensions, severity of peripheral vascular disease, and status of the coronary arteries. Aortic regurgitation, which is caused by incompetent closure of the aortic valve, likewise leads to the appearance of jets on MR images. The severity of regurgitation is graded on the basis of valvular morphologic parameters; qualitative assessment of dephasing jets at Doppler ultrasonography; or measurements of the regurgitant fraction, volume, and orifice area. Mild regurgitation is managed conservatively, whereas severe or symptomatic regurgitation usually leads to valve replacement surgery, especially in the presence of substantial left ventricular enlargement or dysfunction. Bacterial endocarditis, although less common than aortic stenosis and regurgitation, is associated with substantial morbidity and mortality. Electrocardiographically gated CT reliably demonstrates infectious vegetations and benign excrescences of 1 cm or more on the valve surface, allowing the assessment of any embolic complications.

Evaluation of the aortic and mitral valves with cardiac computed tomography and cardiac magnetic resonance imaging

Cardiac computed tomography (CT) produces high-quality anatomical images of the cardiac valves and associated structures. Cardiac magnetic resonance imaging (MRI) provides images of valve morphology, and allows quantitative evaluation of valvular dysfunction and determination of the impact of valvular lesions on cardiovascular structures. Recent studies have demonstrated that cardiac CT and MRI are important adjuncts to echocardiography for the evaluation of aortic and mitral valvular heart diseases (VHDs). Radiologists should be aware of the technical aspects of cardiac CT and MRI that allow comprehensive assessment of aortic and mitral VHDs, as well as the typical imaging features of common and important aortic and mitral VHDs on cardiac CT and MRI.

Multidetector row computed tomography assessment of the native aortic and mitral valve: a call for routine assessment of left-sided heart valves during coronary computed tomography

Aortic valve stenosis and mitral valve regurgitation are the most common valvular heart diseases (VHD) in Western countries. In daily clinical practice, the diagnosis and evaluation of the severity of VHD is based on clinical findings and imaging. Transthoracic echocardiography is the preferred imaging technique for the initial evaluation of VHD. In patients with inconclusive transthoracic echocardiography, transoesophageal echocardiography can have additional diagnostic value. Cardiac multidetector row computed tomography (MDCT) has proven to have diagnostic value in the evaluation of coronary artery disease in symptomatic patients with a low-to-intermediate pretest probability. The images acquired for coronary assessment also contain diagnostic information on heart valves. The purpose of this review was to discuss the diagnostic value of MDCT for the evaluation of left-sided VHD. We provide an overview of the literature comparing echocardiography and MDCT for VHD assessment focusing on aortic valve and mitral valve disease, and we present clinical recommendations.

Cardiac computed tomography for valve disease

Heart valve disease and coronary heart disease are very prevalent in the general population and often coincide in the same patient. Cardiac computed tomography (CT) makes it possible to noninvasively rule out coronary disease before valve surgery and to potentially avoid invasive heart catheterization in 66% to 75% of patients. The same imaging test provides abundant anatomic and functional information that complements the information from echocardiography, making it possible to characterize the etiology of the valve disease and its repercussions on the heart and aorta, as well as to quantify the severity of disease affecting the valves of the left side of the heart. In this article, we describe the anatomy of the heart valves and the technical requisites of cardiac CT for the study of the valves. We go on to explore the usefulness of CT in the preoperative study of the coronary arteries and in the morphological and functional characterization of valve disease, with special emphasis on the valves of the left side of the heart.

Morphological assessment of the aortic valve using coronary computed tomography angiography, cardiovascular magnetic resonance, and transthoracic echocardiography: comparison with intraoperative findings

To compare the diagnostic accuracies of coronary computed tomography angiography (CCTA), cardiovascular magnetic resonance (CMR), and transthoracic echocardiography (TTE) in aortic valve (AV) morphological assessments with operative findings. We retrospectively enrolled 262 patients who underwent CCTA, CMR, and TTE before AV surgery. Two independent blinded observers assessed AV morphology as being tricuspid, bicuspid, or quadricuspid using three imaging modalities. Interobserver and intermodality agreements were obtained with kappa statistics. The diagnostic accuracies of CCTA, CMR, and TTE for identifying AV morphology (tricuspid vs. non-tricuspid) were compared with intraoperative findings as the reference standard. At surgery, tricuspid AV, bicuspid AV, and quadricuspid AV were present in 179, 80, and 3 patients, respectively. The CCTA and CMR image qualities were all diagnostic. Thirteen cases of TTE were not evaluable due to severe AV calcification. An excellent correlation between CMR and CCTA was seen for the identification of AV morphology (κ = 0.97). Good correlations existed between CCTA and TTE (κ = 0.72) and between CMR and TTE (κ = 0.74). CCTA, CMR, and TTE had an excellent or good interobserver agreement (κ = 0.90, 0.95, and 0.72, respectively). Sensitivity, specificity, and positive and negative predictive values for AV morphology assessment (tricuspid vs. non-tricuspid) were: 97, 95, 98, and 94 % with CCTA (n = 262); 98, 96, 98, and 95 % with CMR (n = 262); and 98, 88, 95, and 96 % with TTE (n = 249). CCTA and CMR are highly accurate for identifying AV morphology.

Bicuspid aortic valve: spectrum of imaging findings at cardiac MDCT and cardiovascular MRI

OBJECTIVE

Cardiac MDCT and cardiovascular MRI have become widely used for the evaluation of cardiovascular disease, including aortic valve disease. The purpose of this article is to present the cardiac MDCT and cardiovascular MRI findings of bicuspid aortic valve, its various complications, and other congenital cardiovascular malformations.

CONCLUSION

Radiologists should be aware of the clinical significance and the varied appearance of bicuspid aortic valve at cardiac MDCT and cardiovascular MRI.

Quantification of aortic regurgitant fraction and volume with multi-detector computed tomography comparison with echocardiography

RATIONALE AND OBJECTIVES

Evaluate quantification of the aortic regurgitant fraction and volume with computed tomography (CT).

MATERIALS AND METHODS

Fifty-three patients with aortic regurgitation (AR) and 29 controls were examined with 64-multi-detector CT coronary angiography and transthoracic echocardiography (TTE). A dedicated software algorithm employing three-dimensional segmentation of left ventricle (LV) and right ventricle (RV) volumes and LV mass was applied. AR volume and fraction was calculated based on RV and LV stroke volumes (SV) and compared with echocardiography. The aortic regurgitant orifice area (ROA) was measured by CT.

RESULTS

A good correlation of the AR fraction and AR volume determined by CT compared to echocardiography was found for mild, moderate, and severe AR with 14.2% ± 9, 28.8% ± 8, and 57.9% ± 9 (r = 0.95, P < .001) for AR fraction, and 15.7 mL ± 11.33 mL ± 14, and 98.9 mL ± 36 for AR volume (r = 0.92, P < .0001), respectively. CT correctly classified severity of AR in 93% of patients based of AR-fraction, and in 89% based on AR volume. The sensitivity and specificity of CT were 98% and specificity 90.3%. The specificity improved to 97%, if the ROA by CT was added as diagnostic criterion.

CONCLUSION

Aortic regurgitation fraction and volume can be accurately quantified from CT coronary angiography datasets. These parameters can assist clinical management, e.g. in case of pending cardiac surgery decision.

Computed tomography evaluation of cardiac valves: a review

Electrocardiograph (ECG)-gated cardiac computed tomography (CT) angiography has great potential for the evaluation of the cardiac valves, with excellent image quality. The evidence-based, established clinical role of ECG-gated CT coronary angiography provides additional valuable information about valve morphology and function. A wide range of valve pathology, including congenital and acquired conditions, infectious endocarditis, and complications of valve replacement, can be assessed by cardiac CT imaging. Despite recent advances in CT technology, echocardiography remains the gold standard for noninvasive cardiac valve evaluation. Nevertheless, important clinical information about the valves can be obtained with coronary CT angiography examinations. Thus cardiac valve morphology and function should be routinely assessed and reported on coronary CT angiography examinations.

Detection of aortic regurgitation with 64-slice multidetector computed tomography (MDCT)

RATIONALE AND OBJECTIVES

To determine the diagnostic accuracy of 64-row multidetector cardiac computed tomography (MDCT) in detecting aortic regurgitation (AR) on prospectively acquired images with trans-thoracic echocardiography (TTE) as a reference standard.

MATERIALS AND METHODS

Forty-three consecutive patients underwent MDCT and TTE. AR was defined on MDCT images acquired at 75% phase of R-R interval as the lack of aortic cusps coaptation. The maximum regurgitant orifice area (ROA) was planimetered and compared to TTE.

RESULTS

All 29 patients with AR on TTE were correctly identified by MDCT. The sensitivity, specificity, positive predictive value, and negative predictive value of MDCT were 100%, 85.7%, 93.5%, and 100%, respectively. Sixteen, nine, and four patients were found to have mild, moderate, and severe AR on TTE, respectively. The corresponding ROA by MDCT were 3.25 +/- 1.04 mm(2), 4.16 +/- 1.19 mm(2), and 11.30 +/- 6.13 mm(2), respectively.

CONCLUSION

MDCT data acquired for the coronary artery evaluation can be used for the detection of aortic regurgitation with high diagnostic accuracy without additional scanning or radiation and can support appropriate referral for TTE.

Central aortic valve coaptation area during diastole as seen by 64-multidetector computed tomography (MDCT)

As multiple new procedures now require better visualization of the aortic valve, we sought to better define the central aortic valve coaptation area seen during diastole on multi-detector row cardiac computed tomography (MDCT). 64-MDCT images of 384 symptomatic consecutive patients referred for coronary artery disease evaluation were included in the study. Planimetric measurements of this area were performed on cross-sectional views of the aortic valve at 75% phase of the cardiac cycle. Planimetric measurement of central regurgitation orifice area (ROA) seen in patients with aortic regurgitation and Hounsfield units of the central aortic valve coaptation area were performed. Mean area of the central aortic valve coaptation area was 5.34 ± 5.19 mm(2) and Hounsfield units in this area were 123.69 ± 31.31 HU. The aortic valve coaptation area (mm(2)) measurement in patients without AR was: 4.90 ± 0.17 and in patients with AR: 10.53 ± 0.26 (P ≤ 0.05). On Bland-Altman analysis a very good correlation between central aortic valve coaptation area and central ROA was found (r = 0.80, P ≤ 0.001). Central aortic valve coaptation area is a central area present at the coaptation of nodules of arantius of aortic cusps during diastole; it is incompetent and increased in size in patients with aortic regurgitation.

Planimetric measurement of the regurgitant orifice area using multidetector CT for aortic regurgitation: a comparison with the use of echocardiography

Objective

This study compared the area of the regurgitant orifice, as measured by the use of multidetector-row CT (MDCT), with the severity of aortic regurgitation (AR) as determined by the use of echocardiography for AR.

Materials and Methods

In this study, 45 AR patients underwent electrocardiography-gated 40-slice or 64-slice MDCT and transthoracic or transesophageal echocardiography. We reconstructed CT data sets during mid-systolic to enddiastolic phases in 10% steps (20% and 35-95% of the R-R interval), planimetrically measuring the abnormally opened aortic valve area during diastole on CT reformatted images and comparing the area of the aortic regurgitant orifice (ARO) so measured with the severity of AR, as determined by echocardiography.

Results

In the 14 patients found to have mild AR, the ARO area was 0.18±0.13 cm² (range, 0.04-0.54 cm²). In the 15 moderate AR patients, the ARO area was 0.36 ± 0.23 cm² (range, 0.09-0.81 cm²). In the 16 severe AR patients, the ARO area was 1.00 ± 0.51 cm² (range, 0.23-1.84 cm²). Receiver-operator characteristic curve analysis determined a sensitivity of 85% and a specificity of 82%, for a cutoff of 0.47 cm², to distinguish severe AR from less than severe AR with the use of CT (area under the curve = 0.91; 95% confidence interval, 0.84-1.00; p < 0.001).

Conclusion

Planimetric measurement of the ARO area using MDCT is useful for the quantitative evaluation of the severity of aortic regurgitation.

Comparison of cardiac computed tomographic angiography to transesophageal echocardiography for evaluation of patients with native valvular heart disease

Retrospectively gated helical cardiac computed tomographic angiography (CCTA) has been reported accurate in the evaluation of isolated valvular abnormalities, but its ability to provide comprehensive assessment of common valvular lesions is not established. We evaluated 56 consecutive patients undergoing 64-detector retrospective electrocardiogram-gated CCTA and transesophageal echocardiography for the presence of aortic and mitral stenoses, aortic and mitral regurgitations, mitral valve prolapse, and tricuspid regurgitation. Two cardiac computed tomographic angiographic readers measured maximum aortic and mitral valve opening areas, assessed for aortic or mitral valve regurgitant area, and evaluated for mitral valve prolapse. Tricuspid regurgitation was assessed by the contrast ratio of the inferior vena cava to the right heart. After excluding nondiagnostic valves on CCTA (mitral valve n = 4, aortic valve n = 2), the sensitivity, specificity, positive predictive values, and negative predictive values of CCTA compared to transesophageal echocardiography were 100%, 96%, 50%, and 100% for aortic stenosis, 44%, 96%, 67%, and 90% for aortic regurgitation, 100% each for mitral stenosis, 13%, 95%, 80%, and 45% for mitral regurgitation, and 50%, 98%, 80%, and 91% for mitral valve prolapse. There was no relation between tricuspid regurgitation grade and contrast ratio (p = 0.53). There was excellent interobserver agreement for aortic and mitral stenoses (kappa = 1.0 for each), and good agreement for aortic regurgitation, mitral regurgitation, and mitral valve prolapse (kappa = 0.81, 0.78, and 0.88, respectively). In conclusion, CCTA exhibited high diagnostic performance for detection of aortic and mitral stenoses and limited diagnostic performance for aortic regurgitation, mitral regurgitation, and mitral valve prolapse; tricuspid regurgitation could not be evaluated. The ability of CCTA to provide comprehensive assessment of valvular function is variable.

Helical prospective ECG-gating in cardiac computed tomography: radiation dose and image quality

Helical prospective ECG-gating (pECG) may reduce radiation dose while maintaining the advantages of helical image acquisition for coronary computed tomography angiography (CCTA). Aim of this study was to evaluate helical pECG-gating in CCTA in regards to radiation dose and image quality. 86 patients undergoing 64-multislice CCTA were enrolled. pECG-gating was performed in patients with regular heart rates (HR) < 65 bpm; with the gating window set at 70-85% of the cardiac cycle. All patients received oral and some received additional IV beta-blockers to achieve HR < 65 bpm. In patients with higher or irregular HR, or for functional evaluation, retrospective ECG-gating (rECG) was performed. The average X-ray dose was estimated from the dose length product. Each arterial segment (modified AHA/ACC 17-segment-model) was evaluated on a 4-point image quality scale (4 = excellent; 3 = good, mild artefact; 2 = acceptable, some artefact, 1 = uninterpretable). pECG-gating was applied in 57 patients, rECG-gating in 29 patients. There was no difference in age, gender, body mass index, scan length or tube output settings between both groups. HR in the pECG-group was 54.7 bpm (range, 43-64). The effective radiation dose was significantly lower for patients scanned with pECG-gating with mean 6.9 mSv +/- 1.9 (range, 2.9-10.7) compared to rECG with 16.9 mSv +/- 4.1 (P < 0.001), resulting in a mean dose reduction of 59.2%. For pECG-gating, out of 969 coronary segments, 99.3% were interpretable. Image quality was excellent in 90.2%, good in 7.8%, acceptable in 1.3% and non-interpretable in 0.7% (n = 7 segments). For patients with steady heart rates <65 bpm, helical prospective ECG-gating can significantly lower the radiation dose while maintaining high image quality.

CT angiography of the cardiac valves: normal, diseased, and postoperative appearances

Although echocardiography remains the principal imaging technique for assessment of the cardiac valves, contrast material-enhanced electrocardiographically gated computed tomographic (CT) angiography is proving to be an increasingly valuable complementary modality in this setting. CT angiography allows excellent visualization of the morphologic features and function of the normal valves, as well as of a wide range of valve diseases, including congenital and acquired diseases, infectious endocarditis, and complications of valve replacement. The number, thickness, and opening and closing of the valve leaflets, as well as the presence of valve calcification, can be directly observed. CT angiography also permits simultaneous assessment of the valves and coronary arteries, which may prove valuable in presurgical planning. Unlike echocardiography and magnetic resonance imaging, however, CT angiography requires ionizing radiation and does not provide a direct measure of the valvular pressure gradient. Nevertheless, with further development of related imaging techniques, CT angiography can be expected to play an increasingly important role in the evaluation of the cardiac valves. Supplemental material available at http://radiographics.rsna.org/cgi/content/full/29/5/1393/DC1.

Evaluation of cardiac valves using multidetector CT

Cardiac CT is an accurate and reasonable alternative modality for valvular imaging. It is used primarily for the evaluation of coronary artery disease; however, important information regarding valvular anatomy and function can be derived from CT. Calcification is a common CT finding in various valvular abnormalities and carries important diagnostic and prognostic value. In addition, valvular morphology, stenosis, and regurgitation also are detected on contrast enhanced scans, with good correlation with trans-thoracic echocardiography and other techniques.

Unusual aortic localization of a malignant epithelial tumor metastasis of unknown origin

Both primary aortic tumors and aortic metastasis of primary cancers is extremely rare. In most cases, diagnosis is established late in the course of the disease and management is challenging. We present a unique case of a 68-year-old woman with an unusual aortic localization of a metastasis of unknown origin.

Classic images: Cardiac computed tomography

Cardiac computed tomography (CT) has evolved into a valuable clinical tool for cardiac evaluation. Cardiac CT is increasingly used for imaging of the coronary arteries for the evaluation of (suspected) coronary artery disease, but many other cardiac structures may be the topic for CT investigation. This article reviews general indications for cardiac CT imaging. Common variants and pathologies of the cardiovascular system are illustrated by clinical examples.

Clinical relevance and scope of accidental extracoronary findings in coronary computed tomography angiography: a cardiac versus thoracic FOV study

OBJECTIVE

To assess the spectrum and clinical relevance of extracoronary findings in coronary CT angiography (CCTA), and to compare a small (cardiac) field of view (FOV) to a large (thoracic) FOV setting.

MATERIAL AND METHODS

1084 consecutive patients (mean 57 years) with low-to-intermediate risk of coronary artery disease were enrolled. 542 CCTA scans were interpreted with small FOV (160-190mm(2)) encompassing the cardiac region. In another 542 CCTA (patients matched for age and gender), read-out of an additional full FOV (>320mm(2)) covering the thorax was performed. Clinical relevance of extracoronary findings was considered as either "significant" or "non-significant". "Significant" findings were subclassified as either score 1: findings necessitating immediate therapeutic actions, or score 2: findings with undoubted clinical or prognostic relevance, requiring clinical awareness, follow-up or further investigations (non-urgent). "Non-significant" findings were assigned to either score 3: findings not requiring follow-up or further tests, or as score 4: irrelevant incidental findings.

RESULTS

Significantly more patients with extracoronary findings were identified by using a full FOV with 43.2% (234/542) compared to a small FOV with 33.6% (182/542) (p=0.001). Similarly, a higher total number of extracoronary findings (n=394) was found on full FOV compared to small FOV (n=250) (p<0.001). The detection rate of clinically significant findings was higher by using full FOV compared to small FOV (25.6% versus 15.4%) (p<0.001), out of those 2.2% versus 1.8% of findings required immediate actions (score 1), and 23.4% versus 13.6% (p=0.0001), respectively were of clinical relevance (non-urgent, score 2). The rate of malign findings was 0.2%, and of acute pulmonary embolism 0.1%. More lung pathologies were observed by using full FOV compared to small FOV (22% versus 7%) (p<0.0001), and the detection rate of intrapulmonary nodules increased by 2.1%. Prevalence of aortic valve calcification (n=72) was 13.3%, out of those 7% had less than 2cm(2) aortic valve orifice area.

CONCLUSIONS

The interpretation of extracoronary findings on CCTA scans is mandatory given high prevalence of clinically significant findings by using a full "thoracic" FOV.