The Aortic Root: Comparison of Measurements From ECG-gated CT Angiography With Transthoracic Echocardiography

Aortic Regurgitation in Bicuspid Aortic Valve: The Role of Multimodality Imaging

The evaluation of aortic regurgitation (AR) in bicuspid valve (BAV) is still a challenge because of the eccentricity of the jet, which may under/overestimate the regurgitation. The commonly used echocardiography parameters (such as vena contracta, pressure half-time, etc.) may not be useful in this kind of patient. A multimodality approach combining echocardiography, cardiac MRI, cardiac CT, and advanced technologies applied to non-invasive cardiac imaging (e.g., 4D flow and strain imaging) may be useful to better quantify regurgitation and to select patients suitable for valve replacement. This review provides an overview of the most recent insights about cardiovascular imaging tools and their utility in BAV evaluation, focusing on chronic regurgitation. We describe the role of multimodality imaging in both diagnosis and risk assessment of this disease, pointing out the advantages and disadvantages of the imaging techniques, aiming to provide a guide to clinicians and cardiovascular imaging specialists in choosing the best imaging tools to use.

Comparative Analysis of Micro-Computed Tomography and 3D Micro-Ultrasound for Measurement of the Mouse Aorta

Aortic aneurysms, life-threatening and often undetected until they cause sudden death, occur when the aorta dilates beyond 1.5 times its normal size. This study used ultrasound scans and micro-computed tomography to monitor and measure aortic volume in preclinical settings, comparing it to the well-established measurement using ultrasound scans. The reproducibility of measurements was also examined for intra- and inter-observer variability, with both modalities used on 8-week-old C57BL6 mice. For inter-observer variability, the μCT (micro-computed tomography) measurements for the thoracic, abdominal, and whole aorta between observers were highly consistent, showing a strong positive correlation (R2 = 0.80, 0.80, 0.95, respectively) and no significant variability (p-value: 0.03, 0.03, 0.004, respectively). The intra-observer variability for thoracic, abdominal, and whole aorta scans demonstrated a significant positive correlation (R2 = 0.99, 0.96, 0.87, respectively) and low variability (p-values = 0.0004, 0.002, 0.01, respectively). The comparison between μCT and USS (ultrasound) in the suprarenal and infrarenal aorta showed no significant difference (p-value = 0.20 and 0.21, respectively). μCT provided significantly higher aortic volume measurements compared to USS. The reproducibility of USS and μCT measurements was consistent, showing minimal variance among observers. These findings suggest that μCT is a reliable alternative for comprehensive aortic phenotyping, consistent with clinical findings in human data.

Updated 2022 ACC/AHA Guideline Improves Concordance Between TTE and CT in Monitoring Marfan Snydrome and Related Disorders, but Relevant Measurement Differences Remain Frequent

Background

Patients diagnosed with Marfan syndrome or a related syndrome require frequent aorta monitoring using imaging techniques like transthoracic echocardiography (TTE) and computed tomography (CT). Accurate aortic measurement is crucial, as even slight enlargement (>2 mm) often necessitates surgical intervention. The 2022 ACC/AHA guideline for Aortic Disease Diagnosis and Management includes updated imaging recommendations. We aimed to compare these with the 2010 guideline.

Methods

This retrospective study involved 137 patients with Marfan syndrome or a related disorder, undergoing TTE and ECG-triggered CT. Aortic diameter measurements were taken based on the old 2010 guideline (TTE: inner edge to inner edge, CT: external diameter) and the new 2022 guideline (TTE: leading edge to leading edge, CT: internal diameter). Bland-Altman plots compared measurement differences.

Results

Using the 2022 guideline significantly reduced differences outside the clinical agreement limit from 49% to 26% for the aortic sinus and from 41% to 29% for the ascending aorta. Mean differences were -0.30 mm for the aortic sinus and +1.12 mm for the ascending aorta using the 2022 guideline, compared to -2.66 mm and +1.21 mm using the 2010 guideline.

Conclusion

This study demonstrates for the first time that the 2022 ACC/AHA guideline improves concordance between ECG-triggered CT and TTE measurements in Marfan syndrome patients, crucial for preventing life-threatening aortic complications. However, the frequency of differences >2 mm remains high.

Clinical Relevance/Application

Accurate aortic diameter measurement is vital for patients at risk of fatal aortic complications. While the 2022 guideline enhances concordance between imaging modalities, frequent differences >2 mm persist, potentially impacting decisions on aortic repair. The risk of repeat radiation exposure from ECG-triggered CT, considered the 'gold standard', continues to be justified.

Pre-operative Imaging of Critical Coarctation of the Aorta: Impact on Surgical Approach and Outcomes

Computed tomographic angiography (CTA) has been increasingly used for the evaluation of infants with aortic arch hypoplasia and coarctation of the aorta. The goals of this study were to compare echocardiographic and CTA findings in critical coarctation of the aorta, to evaluate each modality's influence on surgical approach for repair and determine if pre-operative measurements or surgical approach are associated with residual lesions/re-interventions. This was a single-center retrospective cohort study that included 85 neonates and infants who underwent repair of coarctation/arch hypoplasia by three months of age. Two groups were compared: patients with pre-operative echocardiograms only and patients with both echocardiogram and CTA evaluations. 44 (52%) patients received an echocardiogram and CTA, and 41 (48%) patients received an echocardiogram only. Patients in the CTA + echo group had smaller mitral valve and ascending aorta measurements (p = 0.01). When comparing CTA to echocardiogram measurements, the aortic valve annulus, ascending aorta, proximal and distal transverse arch, and isthmus were smaller on echo (p < 0.01). A smaller aortic valve annulus and aortic root as well as thoracotomy approach were associated with residual gradients/re-intervention (p < 0.01). Our study found that patients who underwent CTA preoperatively had smaller left-sided structures. Aortic measurements were smaller on echocardiogram when compared to CTA. Smaller left-sided structures proximal to the aortic arch and thoracotomy predicted the development of residual lesions/re-intervention. CTA is useful in the surgical planning for neonates with arch hypoplasia/coarctation and may help risk stratify for residual lesions/re-intervention.

Discrepancy of echocardiography and computed tomography in initial assessment and 2-year follow-up for monitoring Marfan syndrome and related disorders

Patients with Marfan syndrome and related disorders are at risk for aortic dissection and aortic rupture and therefore require appropriate monitoring. Computed tomography (CT) and transthoracic echocardiography (TTE) are routinely used for initial diagnosis and follow-up. The purpose of this study is to compare whole-heart CT and TTE aortic measurement for initial work-up, 2-year follow-up, and detection of progressive aortic enlargement. This retrospective study included 95 patients diagnosed with Marfan syndrome or a related disorder. All patients underwent initial work-up including aortic diameter measurement using both electrocardiography-triggered whole-heart CT and TTE. Forty-two of these patients did not undergo aortic repair after initial work-up and were monitored by follow-up imaging within 2 years. Differences between the two methods for measuring aortic diameters were compared using Bland-Altman plots. The acceptable clinical limit of agreement (acLOA) for initial work-up, follow-up, and progression within 2 years was predefined as <  ± 2 mm. Bland-Altman analysis revealed a small bias of 0.2 mm with wide limits of agreement (LOA) from + 6.3 to - 5.9 mm for the aortic sinus and a relevant bias of - 1.6 mm with wide LOA from + 5.6 to - 8.9 mm for the ascending aorta. Follow-up imaging yielded a small bias of 0.5 mm with a wide LOA from + 6.7 to - 5.8 mm for the aortic sinus and a relevant bias of 1.1 mm with wide LOA from + 8.1 to - 10.2 mm for the ascending aorta. Progressive aortic enlargement at follow-up was detected in 57% of patients using CT and 40% of patients using TTE. Measurement differences outside the acLOA were most frequently observed for the ascending aorta. Whole-heart CT and TTE measurements show good correlation, but the frequency of measurement differences outside the acLOA is high. TTE systematically overestimates aortic diameters. Therefore, whole-heart CT may be preferred for aortic monitoring of patients with Marfan syndrome and related disorders. TTE remains an indispensable imaging tool that provides additional information not available with CT.

ACR Appropriateness Criteria® Nontraumatic Aortic Disease

Nontraumatic aortic disease can be caused by a wide variety of disorders including congenital, inflammatory, infectious, metabolic, neoplastic, and degenerative processes. Imaging examinations such as radiography, ultrasound, echocardiography, catheter-based angiography, CT, MRI, and nuclear medicine examinations are essential for diagnosis, treatment planning, and assessment of therapeutic response. Depending upon the clinical scenario, each of these modalities has strengths and weaknesses. Whenever possible, the selection of a diagnostic imaging examination should be based upon the best available evidence. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment. The purpose of this document is to assist physicians select the most appropriate diagnostic imaging examination for nontraumatic aortic diseases.

Aortic root measurement on CT: linear dimensions, aortic root area and comparison with echocardiography. A retrospective cross sectional study

OBJECTIVE

We sought to assess the different CT aortic root measurements and determine their relationship to transthoracic echocardiography (TTE).

METHODS

TTE and ECG-gated CT images were reviewed from 70 consecutive patients (mean age 54 ± 18 years; 67% male) with tricuspid aortic roots (trileaflet aortic valves) between Nov 2009 and Dec 2013. Three CT planes (coronal, short axis en face and three-chamber) were used for measurement of nine linear dimensions. TTE aortic root dimension was measured as per guidelines from the parasternal long axis view.

RESULTS

All CT short axis measurements of the aortic root had excellent reproducibility (intraclass correlation coefficient, ICC 0.96-0.99), while coronal and three-chamber planes had lower reproducibility with ICC 0.90 (95% CI 0.84-0.94) and ICC 0.92 (0.87-0.95) respectively. CT coronal and short axis maximal dimensions were systematically larger than TTE (mean 2 mm larger, p < 0.001), while CT cusp to commissure measurements were systematically smaller (CT RCC-comm mean 2 mm smaller than TTE, p < 0.001). All CT short axis measurements had excellent correlation with aortic root area with CT short axis maximal dimension marginally better than the rest (Pearson's R 0.97).

CONCLUSION

Systematic differences exist between CT and TTE dependent on the CT plane of measurement. All CT short axis measurements of the aortic root had excellent reproducibility and correlation with aortic root area with maximal dimension appearing marginally better than the rest. Our findings highlight the importance of specifying the chosen plane of aortic root measurement on CT.

ADVANCES IN KNOWLEDGE

Systematic differences in aortic root dimension exist between TTE and the various CT measurement planes. CT coronal and short axis maximal dimensions were systematically larger than TTE, while CT cusp to commissure measurements were smaller. CT readers should indicate the plane of measurement and the specific linear dimension to avoid ambiguity in follow-up and comparison.

The Association between Morphological and Functional Characteristics of the Bicuspid Aortic Valve and Bicuspid Aortopathy

Objective

To identify the association between morphological and functional characteristics of the bicuspid aortic valve (BAV) and bicuspid aortopathy and to identify the determinants of aortic dilatation using transthoracic echocardiography (TTE) and cardiac computed tomography (CCT).

Materials and Methods

This study included 312 subjects (mean [SD] age, 52.7 [14.3] years; 227 males [72.8%]) who underwent TTE and CCT. The BAVs were classified by anterior-posterior (BAV-AP) or right-left (BAV-RL) orientation of the cusps and divided according to the presence (raphe+) or absence of a raphe (raphe−) based on the CCT and intraoperative findings. The dimensions of the sinus of Valsalva and the proximal ascending aorta were measured by CCT. We assessed the determinants of aortic root and proximal ascending aortic dilatation (size index > 2.1 cm/m²) by Univariable and multivariable logistic regression analyses.

Results

Of the 312 patients, BAV-AP was present in 188 patients (60.3%), and 185 patients (59.3%) were raphe+. Moderate-to-severe aortic stenosis (AS) was the most common hemodynamic abnormality (54.8%). The most common type of aortopathy was the combined dilated root and mid-ascending aortic phenotype (62.5%). On multivariable analysis, age and AS severity were significantly associated with aortic root dilatation (p < 0.05), and age, sex, and AS severity were significantly associated with ascending aortic dilatation (p < 005). However, the orientation of the cusps, presence of a raphe, and severity of aortic regurgitation were not associated with aortic root and ascending aortic dilatation.

Conclusion

BAV morphological characteristics were not determinants of aortic dilatation. Age, sex, and AS severity were predictors of bicuspid aortopathy. Therefore, age, sex, and AS severity, rather than valve morphology, need to be considered when planning treatment for BAV patients.

Three-dimensional volumetric measurement of the aortic root compared to standard two-dimensional measurements using cardiac computed tomography

INTRODUCTION

Two-dimensional measurements are self-evidently limited when seeking accurately to represent the three-dimensional complexity of the aortic root. Volumetric measurement, therefore, seems an ideal alternative for a more accurate assessment.

MATERIALS AND METHODS

We retrospectively analyzed 123 individuals undergoing cardiac computed tomography. We measured the dimensions of the sinuses of Valsalva using routine multiplanar short axis imaging. Three conventional two-dimensional methods were applied to measure the dimensions of the sinuses. These involved bisecting center of sinus-to-center of interleaflet triangle measures, along with center of sinus-to-center of sinus, and largest sinus-to-sinus measurements. We then quantified the volumes of the root using the volume-rendering method.

RESULTS

The mean dimensions of the sinuses were significantly greater when measured using the largest sinus-to-sinus method as opposed to center of sinus-to-center of interleaflet triangle and center of sinus-to-center of sinus methods (33.6 ± 3.6 mm vs. 31.1 ± 3.1 mm and 30.9 ± 3.3 mm, p < .0001). The mean root volume of 13.6 ± 4.2 ml showed the strongest correlation with the mean dimensions of the sinuses of Valsalva measured using the bisecting method (R² = .8401, p < .0001).

CONCLUSIONS

By using two- and three-dimensional measurements, we have provided average data for the structurally normal aortic root. The differences and correlations encountered should be noted when evaluating and following changes in the diseased root.

Multimodality Assessment of Thoracic Aortic Dimensions: Comparison of Computed Tomography Angiography, Magnetic Resonance Imaging, and Echocardiography Measurements

PURPOSE

The purpose of this study was to compare thoracic aortic measurements between computed tomography (CT), magnetic resonance imaging (MRI), and transthoracic echocardiography (TTE).

MATERIALS AND METHODS

A total of 127 patients (mean age: 45±18 y, 49% male) who had undergone CT and MRI evaluation of the thoracic aorta at a single tertiary referral hospital within a 6-month interval between 2007 and 2017 were included in this retrospective study. TTE studies performed within the same 6-month interval were also evaluated. Thoracic aortic measurements were blindly evaluated using multiple techniques and were compared between modalities.

RESULTS

There was no significant difference in maximum aortic root diameter between CT and MRI when using the inner lumen-to-inner lumen technique (mean difference: 0.2±1.4 mm, P=0.51) or the outer lumen-to-outer lumen technique (mean difference: 0.5±1.4 mm, P=0.07). There were no significant differences between CT and MRI at any other level except for the distal descending aorta (20.2±4.6 vs. 19.8±4.6 mm, P<0.001). However, aortic root measurements by TTE using the leading edge-to-leading edge technique were significantly smaller compared with maximum aortic root diameters using the inner lumen-to-inner lumen and outer lumen-to-outer lumen techniques by both CT (mean difference: 4.9±2.7 mm, P<0.001 and 7.4±2.8 mm, P<0.001, respectively) and MRI (mean difference: 4.8±3.2 mm, P<0.001 and 8.2±3.0 mm, P<0.001, respectively).

CONCLUSIONS

There is excellent agreement in thoracic aortic measurements between CT and MRI. However, TTE significantly underestimates maximum aortic root diameter compared with CT and MRI. Therefore, caution should be used when interpreting small apparent changes in aortic root diameters between TTE and CT or MRI.

The American Association for Thoracic Surgery consensus guidelines on bicuspid aortic valve-related aortopathy: Full online-only version

Bicuspid aortic valve disease is the most common congenital cardiac disorder, being present in 1% to 2% of the general population. Associated aortopathy is a common finding in patients with bicuspid aortic valve disease, with thoracic aortic dilation noted in approximately 40% of patients in referral centers. Several previous consensus statements and guidelines have addressed the management of bicuspid aortic valve-associated aortopathy, but none focused entirely on this disease process. The current guidelines cover all major aspects of bicuspid aortic valve aortopathy, including natural history, phenotypic expression, histology and molecular pathomechanisms, imaging, indications for surgery, surveillance, and follow-up, and recommendations for future research. It is intended to provide clinicians with a current and comprehensive review of bicuspid aortic valve aortopathy and to guide the daily management of these complex patients.

The bicuspid aortic valve: Is it an immunological disease process?

Bicuspid aortic valves (BAVs) are the most common congenital cardiac condition and are characterized by a structural abnormality whereby the aortic valve is composed of two leaflets instead of being trileaflet. It is linked to an increased risk for a variety of complications of the aorta, many with an immunological pathogenesis. The aim of this study is to review and analyze the literature regarding immunological processes involving BAVs, associated common pathologies, and their incidence in the population. This study will also examine current trends in surgical and therapeutic approaches to treatment and discuss the future direction of BAV treatment.

Left ventricular geometric patterns in patients with type A aortic dissection

BACKGROUND

Aortic dilatation is a major risk factor for aortic dissection. The aim of the present study was to assess the relationship between left ventricular (LV) geometry and maximal ascending aorta (MAA).

METHODS

We reviewed data from patients who were diagnosed with acute type A aortic dissection and who underwent surgical management from December 2002 to March 2016 at Dong-A University Hospital. Among 151 patients with non-Marfan aortic dissection in the study, 50 who had echocardiography preoperatively were investigated and MAA diameter was analyzed by LV geometric patterns.

RESULTS

Patients' mean age was 59.6 ± 13.5 years and 38.0% were male. The mean MAA diameter was 52.9 ± 8.5 mm. MAA diameter was significantly correlated with LV mass index (r = 0.62, P < 0.001). On analysis by LV geometry, MAA diameter showed a significant difference between the 4 groups (P = 0.02), and the eccentric and concentric hypertrophy groups showed significantly larger MAA diameter than the other two groups.

CONCLUSION

MAA diameter was associated with LV mass index and was significantly different between LV geometry types. In this study, not only concentric hypertrophy but also eccentric LV hypertrophy was related to larger MAA in type A aortic dissection patients.

Electrocardiography-gated cardiac CT angiography can differentiate brachycephalic dogs with and without pulmonary valve stenosis and findings differ from transthoracic echocardiography

Pulmonary valve stenosis (PS) is one of the most commonly diagnosed congenital heart defects in dogs. Currently, transthoracic echocardiography (TTE) is the standard modality used to evaluate PS. Image acquisition by TTE can be challenging in some brachycephalic breeds of dogs. The use of echocardiographic-gated CT angiography (ECG-gated CTA) in veterinary medicine is limited. This retrospective method comparison study investigated right and left ventricular outflow diameters by sedated ECG-gated CTA and unsedated TTE in 14 brachycephalic dogs with PS and 12 brachycephalic dogs without PS. Measurements of ventricular outflow structures were made in early systole and end diastole for both modalities and then compared for significance between systolic and diastolic phases, as well as between the two modalities. Ratios of the pulmonary trunk diameter to the aorta at different locations (aortic valve, aortic annulus, and ascending aorta) and in different planes (transverse, sagittal) were compared between dogs with PS and without PS, as well as within dogs, by both TTE and ECG-gated CTA. Transthoracic echocardiography and ECG-gated CTA both detected significantly greater pulmonary trunk to aorta ratios in dogs with PS at all aortic locations (P < 0.05). Pulmonary valve to aortic valve ratios were significantly smaller in dogs with PS (P < 0.05). Pulmonary trunk to aorta and pulmonary valve to aorta ratios were achieved with good anatomic detail using ECG-gated CTA. Ratios of the pulmonary trunk and pulmonary valve relative to the aorta may be useful to evaluate for PS using a modality that is underutilized for cardiac assessment.

Bicuspid aortic valve outcomes

BACKGROUND

Bicuspid aortic valve is the most common CHD. Its association with early valvular dysfunction, endocarditis, thoracic aorta dilatation, and aortic dissection is well established.

OBJECTIVE

The aim of this study was to assess the incidence and predictors of cardiac events in adults with bicuspid aortic valve.

METHODS

We carried out a retrospective analysis of cardiac outcomes in ambulatory adults with bicuspid aortic valve followed-up in a tertiary hospital centre. Outcomes were defined as follows: interventional - intervention on the aortic valve or thoracic aorta; medical - death, aortic dissection, aortic valve endocarditis, congestive heart failure, arrhythmias, or ischaemic heart disease requiring hospital admission; and a composite end point of both. Kaplan-Meier curves were generated to determine event rates, and predictors of cardiac events were determined by multivariate analysis.

RESULTS

A total of 227 patients were followed-up over 13±9 years; 29% of patients developed severe aortic valve dysfunction and 12.3% reached ascending thoracic aorta dimensions above 45 mm. At least one cardiac outcome occurred in 38.8% of patients, with an incidence rate at 20 years of follow-up of 47±4%; 33% of patients were submitted to an aortic valve or thoracic aorta intervention. Survival 20 years after diagnosis was 94±2%. Independent predictors of the composite end point were baseline moderate-severe aortic valve dysfunction (hazard ratio, 3.19; 95% confidence interval, 1.35-7.54; p<0.01) and aortic valve leaflets calcification (hazard ratio, 4.72; 95% confidence interval, 1.91-11.64; p<0.005).

CONCLUSIONS

In this study of bicuspid aortic valve, the long-term survival was excellent but with occurrence of frequent cardiovascular events. Baseline aortic valve calcification and dysfunction were the only independent predictors of events.

Aortic root dimensions are predominantly determined by genetic factors: a classical twin study

OBJECTIVES

Previous studies using transthoracic echocardiography (TTE) observed moderate heritability of aortic root dimensions. Computed tomography angiography (CTA) might provide more accurate heritability estimates. Our primary aim was to assess the heritability of the aortic root with CTA. Our secondary aim was to derive TTE-based heritability and compare this with the CTA-based results.

METHODS

In the BUDAPEST-GLOBAL study 198 twin subjects (118 monozygotic, 80 dizygotic; age 56.1 ± 9.4 years; 126 female) underwent CTA and TTE. We assessed the diameter of the left ventricular outflow tract (LVOT), annulus, sinus of Valsalva, sinotubular junction and ascending aorta. Heritability was assessed using ACDE model (A additive genetic, C common environmental, D dominant genetic, E unique environmental factors).

RESULTS

Based on CTA, additive genetic effects were dominant (LVOT: A = 0.67, E = 0.33; annulus: A = 0.76, E = 0.24; sinus of Valsalva: A = 0.83, E = 0.17; sinotubular junction: A = 0.82, E = 0.18; ascending aorta: A = 0.75, E = 0.25). TTE-derived measurements showed moderate to no genetic influence (LVOT: A = 0.38, E = 0.62; annulus: C = 0.47, E = 0.53; sinus of Valsalva: C = 0.63, E = 0.37; sinotubular junction: C = 0.45, E = 0.55; ascending aorta: A = 0.67, E = 0.33).

CONCLUSION

CTA-based assessment suggests that aortic root dimensions are predominantly determined by genetic factors. TTE-based measurements showed moderate to no genetic influence. The choice of measurement method has substantial impact on heritability estimates.

KEY POINTS

• Aortic root dimensions are determined by genetic and environmental effects. • Transthoracic echocardiography (TTE) demonstrated moderate to no genetic effects on aortic root dimensions. • Computed tomography angiography might provide more accurate heritability estimates compared to TTE. • Three-dimensional imaging techniques are needed to reliably quantify aortic root dimensions.

Proximal thoracic aortic diameters: transesophageal-echocardiography- versus computed-tomography-derived measurements

PURPOSE

The purpose of the study was to compare proximal aortic measurements from electrocardiogram-gated computed tomography (CT) to transesophageal echocardiography (TEE) and to evaluate differences in cusp-cusp and cusp-commissure CT measurements of sinus of Valsalva (SOV).

METHODS

This retrospective study (n=25) compared aortic diameters from CT using manual double-oblique multiplanar reformats (MPRs) and semiautomatic centerline method to TEE.

RESULTS

CT MPR and centerline measurements were higher than TEE for sinotubular junction and ascending aorta. At SOV, cusp-cusp diameters (MPR and centerline methods) and cusp-commissure measurement (centerline method) were larger than TEE.

CONCLUSIONS

Aortic measurements were larger on CT than TEE. Precise difference depended on location and measurement technique.

Bicuspid aortic valve aortopathy in adults: Incidence, etiology, and clinical significance

Bicuspid aortic valve is the most common congenital heart defect and is associated with an aortopathy manifested by dilatation of the ascending thoracic aorta. The clinical consequences of this aortopathy are the need for periodic monitoring of aortic diameters, elective prophylactic surgical aortic repair, and the occurrence of aortic dissection or rupture. This review describes the current knowledge of BAV aortopathy in adults, including incidence, pathophysiologic insights into its etiology, contemporary hypothesis-generating observations into its complications, and recommendations for monitoring and intervention.

Diseases of the Aorta in Elite Athletes

Sudden cardiovascular deaths in athletes are rare and only a fraction are due to aortic events. There has been concern that the hemodynamic load during exercise may lead to aortic dilation, but aortic dimensions in endurance and strength-trained athletes are only slightly larger than those in sedentary comparison subjects. The presence of a bicuspid aortic valve without significant valvular dysfunction and normal aortic dimensions should not influence eligibility to practice sport. Patients with genetic syndromes associated with aortopathy generally should be restricted from vigorous sports participation. This article reviews the diagnosis and management of diseases of the aorta in athletes.

A comparative analysis of ECG-gated steady state free precession magnetic resonance imaging versus transthoracic echocardiography for evaluation of aortic root dimensions

PURPOSE

Accurate and reproducible measurement of aortic root dimensions is essential to inform clinical decision making. Transthoracic echocardiography (TTE) is the first line test for assessment of the aortic root but has potential limitations due to its limited field of view and restricted acoustic windows. Cardiac magnetic resonance imaging (MRI) is considered the "gold standard" technique for assessment of cardiac morphology and recently MRI reference ranges for aortic root dimensions have been published. The purpose of this study was to retrospectively compare aortic root measurements obtained from TTE with those derived from cardiac MRI.

MATERIALS AND METHODS

Sixty-eight patients (40 males, 28 females) who had undergone both cardiac MRI and TTE imaging within a 4-month interval (mean 62 days) were included. Steady-state-free precession MRI cine imaging was performed with an acquisition plane perpendicular to the aortic root and through the true cross sectional aortic valve plane. A cusp-commissure dimension from inside wall to inside wall in end-diastole was recorded and compared with standardized TTE derived Valsalva sinus measurements. Pearson correlation coefficients and a paired t-test were used for statistical analysis.

RESULTS

Mean aortic root dimension by TTE was 3.2±0.5 cm and MRI was 3.4±0.4 cm with a Pearson correlation coefficient of >0.7. Mean difference between TTE and MRI was 0.2±0.3 (P<0.001) with MRI producing a consistently higher measure. In four patients with a dilated aortic root by MRI the TTE measurement was within the normal reference range. In patients with a dilated aortic root (n=19) the mean difference was 0.2±0.4 cm (P<0.05) with MRI consistently producing the larger measure. In patients with a non-dilated aortic root t (n=49) the mean difference was 0.2±0.3 cm (P<0.05) with MRI consistently producing the larger measure.

CONCLUSIONS

There is a high level of correlation between TTE and MRI derived aortic root measurements at the Valsalva sinus level. MRI consistently measures the aortic root dimension higher than TTE which may under diagnose patients with a mildly dilated aortic root. Further investigation is required to properly integrate MRI into imaging assessment algorithms.

Multi-detector CT angiography of the aortic valve-Part 1: anatomy, technique and systematic approach to interpretation

The aortic valve and adjacent structures should be routinely evaluated on all thoracic cross-sectional imaging studies. Echocardiography and magnetic resonance imaging (MRI) are the main imaging techniques used for assessment of the aortic valve and related pathology but multi-detector computed tomography (MDCT) can offer valuable complimentary information in some clinical scenarios. Radiologists should be familiar with the indications, advantages and limitations of MDCT for assessment of the aortic valve. This article reviews aortic valve anatomy and relevant terminology, technical aspects of MDCT image optimisation and describes a suggested approach to interpretation.

Aortic root disease in athletes: aortic root dilation, anomalous coronary artery, bicuspid aortic valve, and Marfan's syndrome

Two professional athletes in the U.S. National Basketball Association required surgery for aortic root dilation in 2012. These cases have attracted attention in sports medicine to the importance of aortic root disease in athletes. In addition to aortic root dilation, other forms of aortic disease include anomalous coronary artery, bicuspid aortic valve, and Marfan's syndrome. In this review, electronic database literature searches were performed using the terms "aortic root" and "athletes." The literature search produced 122 manuscripts. Of these, 22 were on aortic root dilation, 21 on anomalous coronary arteries, 12 on bicuspid aortic valves, and 8 on Marfan's syndrome. Aortic root dilation is a condition involving pathologic dilation of the aortic root, which can lead to life-threatening sequelae. Prevalence of the condition among athletes and higher risk athletes in particular sports needs to be better delineated. Normative parameters for aortic root diameter in the general population are proportionate to anthropomorphic variables, but this has not been validated for athletes at the extremes of anthropomorphic indices. Although echocardiography is the favored screening modality, computed tomography (CT) and cardiac magnetic resonance imaging (MRI) are also used for diagnosis and surgical planning. Medical management has utilized beta-blockers, with more recent use of angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), and statins. Indications for surgery are based on comorbidities, degree of dilation, and rate of progression. Management decisions for aortic root dilation in athletes are nuanced and will benefit from the development of evidence-based guidelines. Anomalous coronary artery is another form of aortic disease with relevance in athletes. Diagnosis has traditionally been through cardiac catheterization, but more recently has included evaluation with echocardiography, multislice CT, and MRI. Athletes with this condition should be restricted from participation in competitive sports, but can be cleared for participation 6 months after surgical repair. Bicuspid aortic valve is another form of aortic root disease with significance in athletes. Although echocardiography has traditionally been used for diagnosis, CT and MRI have proven more sensitive and specific. Management of bicuspid aortic valve consists of surveillance through echocardiography, medical therapy with beta-blockers and ARBs, and surgery. Guidelines for sports participation are based on the presence of aortic stenosis, aortic regurgitation, and aortic root dilation. Marfan's syndrome is a genetic disorder with a number of cardiac manifestations including aortic root dilation, aneurysm, and dissection. Medical management involves beta-blockers and ARBs. Thresholds for surgical management differ from the general population. With regard to sports participation, the most important consideration is early detection. Athletes with the stigmata of Marfan's syndrome or with family history should be tested. Further research should determine whether more aggressive screening is warranted in sports with taller athletes. Athletes with Marfan's syndrome should be restricted from activities involving collision and heavy contact, avoid isometric exercise, and only participate in activities with low intensity, low dynamic, and low static components. In summary, many forms of aortic root disease afflict athletes and need to be appreciated by sports medicine practitioners because of their potential to lead to tragic but preventable deaths in an otherwise healthy population.

Cardiovascular magnetic resonance as an alternate method for serial evaluation of proximal aorta: comparison with echocardiography

Thoracic aortic disease is a known cause of aortic dilatation and poses significant risk of aortic dissection and rupture. Serial assessment of aortic root dimensions is traditionally performed using echocardiography, which is limited with older age and following surgery, due to poor acoustic windows. Although diastolic measurements are utilized as standard practice in decision making of adult aortopathy, systolic diameters are utilized in pediatric practice. Three-dimensional steady-state free precision (3D-SSFP) has shown promise as an alternate method for providing accurate and reproducible aortic measurements. The agreement between proximal aorta measurements by diastolic 3D-SSFP and echocardiography (both systole and diastole) was examined in 40 subjects. The maximum inner diameters at aortic annulus, root and sinotubular junction demonstrated excellent agreement between 3D-SSFP and echocardiography for all the 3 levels. The best agreement was observed for diastolic root dimensions with a mean difference of +0.01 cm, limits of agreement being -0.26 to +0.28 cm. Three D-SSFP can be used interchangeably with echocardiography in the serial assessment of the aortic root size. Careful attention to obtain an imaging plane utilizing 3D multiplanar reformatting is critical to maximize the agreement between the two imaging modalities.

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.