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Non-Invasive Imaging of Aortic Valve – Ultrasounds
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Thoracic Aorta and Aortic Arch
Beyond the measurement of the aortic root and the ascending aorta, every TEE should be
completed by the evaluation of thoracic aorta and aortic arch. Starting from a TG or ME at 0°,
the probe must be rotated counterclockwise (to the left of the patient) to display the posterior
descending aorta short axis view (Figure 7).
An image optimization by reducing image depth, setting the focus in the near field and
increasing the gain is recommended. A slow continuous withdrawal of the probe allows to
follow and evaluate the whole wall structure and lumen.
Long axis view is obtainable when increasing the angle up to 90-110°; however, thanks
to the widely available probes with biplane mode, simultaneous short and long axis views are
displayed (Figure 7). At the level of left subclavian artery, the aorta will appear elongated:
this is the cut plane at which aortic arch begins. Usually a slight clockwise rotation of the
probe is needed to show a correct long axis view. Aortic arch short axis view is detected at
70-90°.
Figure 7. Transesophageal evaluation of the thoracic aorta with the X-plane view. The thoracic aorta is
displaced along its long axis (left) and shor axis (right).
3D-Transesophageal Assessment
The use of 3D TEE aims to integrate the AV and LVOT visualization and planimetry,
mostly when 2D images are sub-optimal or partially defined (Figure 8).
Full volume 3D dataset is usually built from the ME AV short and long axis views or
from a ME 60° view, simultaneously optimizing the two 2D images [10]. The size of 3D box
will determine spatial and temporal resolution. Once the 3D image is modeled, the surgical
view of the AV is usually firstly displayed. Moving the crop planes, the AV and LVOT areas
can be traced and calculated with a good accuracy compared to multislice computed
tomography [11]. Experience in 3D echocardiography is needed for the correct interpretation
of images (i.e., discrimination between drop out artifacts and cusps abnormalities). Applying
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CD, 3D VC has been used to estimate AR severity, showing significant correlation with 2D
VC [12].
Figure 8. 3D-transesophageal mid-esophageal (ME) AV short axis view (SAX). The use of 3D
transesophageal echochardiography aims to integrate the AV visualization and planimetry. Full volume
3D dataset is here built from the ME AV SAX simultaneously optimizing 2D images. Once the 3D
image is modeled, the surgical view of the AV is usually displayed. Moving the crop planes, the AV
area can be traced and calculated.
TEE as a Key Tool before and after Percutaneous and Surgical Procedures
The role of TEE is relevant in the decision making of AV functional defects. A complete
report should include: AS/AR etiology, AV anatomic features (BAV or other defects),
dimensions of the whole AV apparatus (crucial for prosthesis sizing), LVOT dimension,
AVA, origin of coronary ostia, degree of calcification of ascending aorta (in case of aortic
clamp). The functional and anatomical data from TEE are integrated with computed
tomography data. During follow up, aortic prostheses are periodically evaluated by TTE.
However, TEE can help in searching perivalvular leaks (due to technical issues during
implant or suture dehiscence) or prosthesis degeneration causing relevant regurgitation, if
TTE images are of poor quality. In addition, a TEE can be requested for the differential
diagnosis between pannus and thrombosis in mechanical prosthesis, even if technically
difficult. Usually, clinical history and the aspect of thrombus (more commonly hyperechoic
and large, with greater interference with disks motion) are key features. Finally, TEE is an
integral diagnostic technique when suspecting prosthesis endocarditis: vegetations, abnormal
valve function, peri-annular abscesses are usually found and quite easily detected [13].
Stress echocardiography (SE), meant as either exercise stress-testing or pharmacological
stress with dobutamine, is widely accepted as a key exam in the diagnostic workup and risk
stratification of patients with AV disease.
Indeed, when appropriate, SE may yield straightforward information about the severity of
valvular dysfunction along with the potential hemodynamic consequences, such as pressure
STRESS ECHOCARDIOGRAPHY
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and volume overload and impaired contractile reserve (CR) [14]. Moreover, the relatively
low-cost, safety, and wide diffusion, make SE an ideal choice in patients with a slowprogressive valve disease and with a poorly active lifestyle, combing information derived
from the exercise-challenge and potentially useful imaging markers [15].
Therefore, during last decades, the clinical setting of AS has seen an increasing demand
of SE, along with the growing number of potential candidates to valve replacement, due to the
ageing population and to the widespread diffusion of percutaneous approaches. In particular,
the main applications of SE in the patient with AS are:
1. The assessment of the physical, hemodynamic, and echocardiographic consequences
of exercise in patients with a known severe AS but with poor active lifestyles,
potentially masking symptoms occurrence.
2. The further stratification of patients showing discrepancies between the AVA and the
transvalvular gradients at rest, in the suspicion of low-flow/low-gradient AS [16].
Conversely, only a marginal role is attributed to SE in patients with chronic AR, probably
due to the lack of large studies in this context [14].
Stress Echocardiography in Aortic Stenosis
Nowadays, due to ageing population, ever more patients receiving a diagnosis of severe
AS complain few symptoms, probably because of sedentary lifestyles. Therefore, it may be
tricky to attribute physical limitations and symptoms to the valvular disease. Moreover, while
AV replacement is clearly indicated in case of reduced LVEF, only symptomatic patients with
severe AS and preserved LVEF should undergo surgery, unless meeting criteria of very
severe AS.
Exercise-testing may then unmask symptoms, significant blood pressure drops and/or
changes in ST-segment, and thus be useful to identify the subgroup of patients that would
benefit more from surgical intervention [17, 18, 19].
In this respect, stress-related increase in mean transvalvular gradient >20 mmHg and a
pulmonary systolic artery pressure >60 mmHg during exercise have been related with a 3.8fold and 2-fold greater risk of cardiac event at follow-up, respectively, also in absence of
other SE criteria [20, 21]. Notwithstanding, the utility of SE in asymptomatic AS has been
challenged in a recent study, in which, among the 112 patients with an otherwise negative
exercise-test, neither the increase in mean transvalvular gradient nor in pulmonary systolic
artery pressure were predictive of outcome [22]. Discrepancies in methodology and study
populations or endpoints have been advocated to explain those contrasting results.
Other parameters have been also proposed in asymptomatic patients with severe AS : an
increase in average E/e’ > 14; a worsening in left ventricular wall motion; a reduced CR
(meant either as LVEF fall/increase <5% or left ventricular global longitudinal strain
fall/increase <-1.4%); an S’-wave velocity increase <5 cm/s [23].
Whether SE may help to properly select the subset of “truly” asymptomatic patients in
which AV surgery may be beneficial is yet to be clarified by large and multicenter
prospective studies.
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Low-Flow Low-Gradient Aortic Stenosis
Dobutamine SE (DSE) represents a key test in the diagnostic algorithm of patients with a
suspected low-flow/low-gradient AS, both in the classical (i.e., in case of reduced LVEF) and
in the paradoxical subtype (i.e., in case of preserved LVEF) [16]. Due to the frailty of such
subgroup of patients, a low-dose dobutamine protocol is usually indicated, with a starting
dose of 2.5 or 5 mg/kg/min and a progressive increment up to 10–20 mg/kg/min, until study
targets have been achieved [3].
The first aim of DSE is to evaluate whether CR is present or absent. In particular, a
recovery of the SV >35 mL/m2, a rise >20% from baseline, and/or a transvalvular flow rate
>200-250 mL/s (as calculated from the ratio between SV and systolic ejection time) are
commonly used as signs of preserved CR. In this case, re-evaluating the AVA in optimized
flow condition may allow to distinguish between a truly severe AS or a pseudo-severe AS.
An increase in the AVA up to value >1 cm2 at any stage of DSE indicates a pseudo-severe AS
and it is often accompanied by no change or only a slight rise of transvalvular gradients.
On the contrary, truly severe AS is suggested by an AS jet velocity ≥4.0 m/s or a mean
gradient ≥40 mmHg, while the AVA remains <1 cm2 [24] (Figure 9).
Figure 9. Dobutamine stress echocardiography for the evaluation of low-flow low-gradient aortic valve
(AV). Parasternal long axis view of the AV showing aortic stenosis (AS) with aortic valve area (AVA)
= 0.7 cm2 in presence of an ejection fraction <50% (panel a). Doppler evaluation of the AV shows a
peak velocity of 3.5 m/s and a mean gradient of 27 mmHg (panel b). To assess the severity of AS in
presence of discordant anatomical and Doppler data, dobutamine stress echo is performed, confirming
an AVA = 0.7 cm2 (panel c). Doppler based data show a peak velocity of 4.3 m/s and a mean gradient
of 43 mmHg, confirming the severity of the stenosis (panel d).
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Whether diagnostic uncertainty still persists after the test, calculating the projected AVA
(i.e., AVA at a normalized flow rate of 250 mL/s) may be considered, by means of a
mathematical formula, firstly proposed by Blais et al.:
Projected AVA = AVArest + (AVA/Q) * (250 – Qrest)
where Q indicates the flow rate and AVA
obtained during DSE and at rest. A projected AVA <1 cm2 indicates a truly severe AS [25].
The clinical relevance of distinguishing between a truly severe and a pseudo-severe AS
lays in the assumption that AV replacement is indicated only in the former situation, while
clinical follow-up is indicated in the latter [17, 18]. Furthermore, the absence of CR at DSE
helps to identify a subset of patients at very high operative risk, to be consequently candidate
to less invasive approaches [16].
Finally, similar criteria may be applied to patients with a suspected paradoxical lowflow/low-gradient AS. Nevertheless, the small cardiac volumes and the restrictive filling
pattern that often characterize these patients, may affect DSE interpretation and require the
use of other diagnostic tools, such as computed tomography, to obtain definitive conclusions
[26].
and Q are the differences between the values
Stress Echocardiography in Aortic Regurgitation
Exercise-SE may help to unmask symptoms in poorly active patients also in the setting of
AR. Nevertheless, whether exercise-testing may provide a better risk stratification in
otherwise asymptomatic patients with AR is still to be elucidated [27]. Therefore, while the
use of SE is considered reasonable in this setting according to American guidelines [17], it is
not even mentioned in the latest European guidelines [18].
A few and relatively small studies have shown that a preserved pre-operative CR could
be a predictor of survival and ventricular decompensation better than other parameters
obtained at resting conditions [28, 29]. Moreover, in the study of Park et al. one-third of
patients with a preserved CR had a LV end-systolic diameter >50 mm, that would have
indicated AV replacement according to current guidelines (class IIa) [17, 18]. The evaluation
of CR may then improve the current ability to allocate asymptomatic patients as potential
candidates to AV replacement [29]. Finally, the possible role of other markers, such as stressrelated changes in longitudinal LV function assessed with tissue Doppler [30, 31] and
tricuspid annular plane systolic excursion measured during exercise [32] seem also to
improve risk stratification of asymptomatic patients with severe AR and preserved LVEF,
encouraging future research in this field.
CONCLUSION
Echocardiography is the first imaging technique of choice to diagnose and grade AS and
AR. The use of multiple views and several qualitative, semiquantitative and quantitative
parameters derived from transthoracic, transesophageal and stress echocardiography may help
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to understand the clinical relevance of AV diseases, to stratify patients’ prognosis and to
understand both the need of an intervention and the timing and choice of the best treatment
modality. With expanding technologies and increasing availability of treatment options such
as transcatheter aortic valve interventions, in addition to conventional surgical approaches,
accurate and precise assessment of AV conformation and disease severity is critical to guide
clinical decisions.
A multiparametric echocardiographic approach, along with the incorporation in certain
scenarios of multimodality imaging (cardiac computed tomography or magnetic resonance
imaging), is now mandatory to avoid incorrect misclassification of AS/AR and to ensure
appropriate selection of patients who would most benefit from AV interventions.
REFERENCES
[1] Basso C, Thiene G, and Ho SV. “Heart valve disease (aortic valve disease): anatomy
and pathology of the aortic valve.” In The EACVI textbook of echocardigraphy, 2nd
edition, edited by Lancellotti PP, Zamorano JL, Habib G, Badano L. 231-233. Oxford:
Oxford University Press (2017).
[2] Baumgartner H, Orwat S, Sade E, and Bermejo J. “Heart valve disease (aortic valve
disease): aortic stenosis. In “The EACVI textbook of echocardigraphy, 2nd edition,”
edited by Lancellotti PP, Zamorano JL, Habib G, Badano L. 234-250. Oxford: Oxford
University Press, (2017).
[3] Baumgartner H, Hung J, Bermejo J, Chambers JB, Edvardsen T, Goldstein S,
Lancellotti P, LeFevre M, Miller F, and Otto CM. “Recommendations on the
echocardiographic assessment of aortic valve stenosis: a focused update from the
European Association of Cardiovascular Imaging and the American Society of
Echocardiography.” J Am Soc Echocardiogr (2017): 373-392.
[4] Zoghbi WA, Adams D, Bonow RO, Enriquez-Sarano M, Foster E, Grayburn, PA Hahn
RT, Han Y, Hung J, Lang RM, Little SH, Shah DJ, Shernan S, Thavendiranathan P,
Thomas JD, and Weissman NJ. “Recommendations for noninvasive evaluation of
native valvular regurgitation. A Report from the American Society of
Echocardiography Developed in Collaboration with the Society for Cardiovascular
Magnetic Resonance.” J Am Soc Echocardiogr (2017): 303-371.
[5] Otto CM. “Valvular regurgitation.” In “Textbook of clinical echocardiography, 6th
edition” edited by Otto CM. 364-345. Philadelphia, Elsevier, (2018).
[6] Verma S, Siu SC. “Aortic Dilatation in Patients with Bicuspid Aortic Valve.” N Engl J
Med (2014): 1920-1929.
[7] Roos-Hesselink JW, Schölzel BE, Heijdra RJ, Spitaels SE, Meijboom FJ, Boersma E,
Bogers AJ, Simoons ML. “Aortic valve and aortic arch pathology after coarctation
repair.” Heart (2003): 1074-1077.
[8] Lang RM, Badano LP, Mor-Avi V, Afilalo J, Armstrong A, Ernande L, Flachskampf
FA, Foster E, Goldstein SA, Kuznetsova T, Lancellotti P, Muraru D, Picard MH,
Rietzschel ER, Rudski L, Spencer KT, Tsang W, Voigt JU. “Recommendations for
cardiac chamber quantification by echocardiography in adults: an update from the
Non-Invasive Imaging of Aortic Valve – Ultrasounds
53
Complimentary Contributor Copy
https://t.me/med1917
American Society of Echocardiography and the European Association of
Cardiovascular Imaging.” J Am Soc Echocardiogr (2015): 1-39.e14.
[9] El Khoury G, Glineur D, Rubay J, Verhelst R, d’Acoz Yd, Poncelet A, Astarci P,
Noirhomme P, van Dyck M. “Functional classification of aortic root/valve
abnormalities and their correlation with etiologies and surgical procedures.” Curr Opin
Cardiol (2005): 115-121.
[10] Hahn RT, Abraham T, Adams MS, Bruce CJ, Glas KE, Lang RM, Reeves ST,
Shanewise JS, Siu SC, Stewart W, Picard MH. “Guidelines for performing a
comprehensive transesophageal echocardiographic examination: recommendations
from the American Society of Echocardiography and the Society of Cardiovascular
Anesthesiologists.” J Am Soc Echocardiogr (2013): 921-964.
[11] Khalique OK, Kodali SK, Paradis JM, Nazif TM, Williams MR, Einstein AJ, Pearson
GD, Harjai K, Grubb K, George I, Leon MB, Hahn RT. “Aortic annular sizing using a
novel 3-dimensional echocardiographic method: use and comparison with cardiac
computed tomography.” Circ Cardiovasc Imaging (2014): 155–163.
[12] Sato H, Ohta T, Hiroe K, Okada S, Shimizu K, Murakami R, Tanabe K. “Severity of
aortic regurgitation assessed by area of vena contracta: a clinical two-dimensional and
three-dimensional color Doppler imaging study.” Cardiovasc Ultrasound (2015): 24.
[13] Flachskampf FA, Wouters PF, Edvardsen T, Evangelista A, Habib G, Hoffman P,
Hoffmann R, Lancellotti P, Pepi M. “Recommendations for transoesophageal
echocardiography: EACVI update 2014.” Eur Heart J Cardiovasc Imaging (2014):
353-365.
[14] Gentry Iii JL, Phelan D, Desai MY, Griffin BP. “The Role of Stress Echocardiography
in Valvular Heart Disease: A Current Appraisal.” Cardiology (2017): 137-150.
[15] Pierard LA, Lancellotti P. “Stress testing in valve disease.” Heart (2007): 766–772.
[16] Lancellotti P, Pellikka PA, Budts W, Chaudhry FA, Donal E, Dulgheru R, Edvardsen T,
Garbi M, Ha JW, Kane GC, Kreeger J, Mertens L, Pibarot P, Picano E, Ryan T, Tsutsui
JM, Varga A. “The Clinical Use of Stress Echocardiography in Non-Ischaemic Heart
Disease: Recommendations from the European Association of Cardiovascular Imaging
and the American Society of Echocardiography.” J Am Soc Echocardiogr (2017): 101-
138.
[17] Nishimura RA, Otto CM, Bonow RO, Carabello BA, Erwin JP 3rd, Guyton RA,
O’Gara PT, Ruiz CE, Skubas NJ, Sorajja P, Sundt TM 3rd, Thomas JD; ACC/AHA
Task Force Members. “2014 AHA/ACC Guideline for the Management of Patients
With Valvular Heart Disease: a report of the American College of
Cardiology/American Heart Association Task Force on Practice Guidelines.”
Circulation (2014): e521-643.
[18] Baumgartner H, Falk V, Bax JJ, De Bonis M, Hamm C, Holm PJ, Iung B, Lancellotti P,
Lansac E, Rodriguez Muñoz D, Rosenhek R, Sjögren J, Tornos Mas P, Vahanian A,
Walther T, Wendler O, Windecker S, Zamorano JL; ESC Scientific Document Group.
“2017 ESC/EACTS Guidelines for the management of valvular heart disease.” Eur
Heart J (2017): 2739-2791.
[19] Magne J, Lancellotti P, Piérard LA. “Exercise testing in asymptomatic severe aortic
stenosis.” JACC Cardiovasc Imaging (2014): 188-199.
Alberto Giannoni, Chiara Borrelli, Giulia Elena Mandoli et al.
54
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https://t.me/med1917
[20] Lancellotti P, Lebois F, Simon M, Tombeux C, Chauvel C, Pierard LA. “Prognostic
importance of quantitative exercise Doppler echocardiography in asymptomatic
valvular aortic stenosis.” Circulation (2005): 1377–1382.
[21] Lancellotti P, Magne J, Donal E, O’Connor K, Dulgheru R, Rosca M, Pierard LA.
“Determinants and prognostic significance of exercise pulmonary hypertension in
asymptomatic severe aortic stenosis.” Circulation (2012): 851–859.
[22] Goublaire C, Melissopoulou M, Lobo D, Kubota N, Verdonk C, Cimadevilla C,
Codogno I, Brochet E, Vahanian A, Messika-Zeitoun D. “Prognostic value of
exercise‑stress echocardiography in asymptomatic patients with aortic valve stenosis.”
JACC Cardiovasc Imaging (2018): 787‑795.
[23] Burkule N. “Stress echocardiography in aortic stenosis.” J Clin Prev Cardiol (2019):
64-70.
[24] deFilippi CR, Willett DL, Brickner ME, Appleton CP, Yancy CW, Eichhorn EJ,
Grayburn PA. “Usefulness of dobutamine echocardiography in distinguishing severe
from nonsevere valvular aortic stenosis in patients with depressed left ventricular
function and low transvalvular gradients.” Am J Cardiol (1995): 191-194.
[25] Blais C, Burwash IG, Mundigler G, Dumesnil JG, Loho N, Rader F, Baumgartner H,
Beanlands RS, Chayer B, Kadem L, Garcia D, Durand LG, Pibarot P. “Projected valve
area at normal flow rate improves the assessment of stenosis severity in patients with
low-flow, low-gradient aortic stenosis: the multicenter TOPAS (Truly or Pseudo-Severe
Aortic Stenosis) study.” Circulation (2006): 711-721.
[26] Clavel MA, Ennezat PV, Maréchaux S, Dumesnil JG, Capoulade R, Hachicha Z,
Mathieu P, Bellouin A, Bergeron S, Meimoun P, Arsenault M, Le Tourneau T, Pasquet
A, Couture C, Pibarot P. “Stress echocardiography to assess stenosis severity and
predict outcome in patients with paradoxical low-flow, low-gradient aortic stenosis and
preserved LVEF.” JACC Cardiovasc Imaging (2013): 175-183.
[27] Lancellotti P and Magne J. “Stress Echocardiography in Regurgitant Valve Disease.”
Circ Cardiovasc Imaging (2013): 840-849.
[28] Wahi S, Haluska B, Pasquet A, Case C, Rimmerman CM and Marwick TH. “Exercise
echocardiography predicts development of left ventricular dysfunction in medically and
surgically treated patients with asymptomatic severe aortic regurgitation.” Heart
(2000): 606-614.
[29] Park SJ, Enriquez-Sarano M, Song JE, Lee YJ, Ha MR, Chang SA, Choi JO, Lee SC,
Park SW, Oh JK. “Contractile reserve determined on exercise echocardiography in
patients with severe aortic regurgitation.” Circ J (2013): 2390-2398.
[30] Helin LM1, Tamás E, Nylander E. “Preoperative longitudinal left ventricular function
by tissue Doppler echocardiography at rest and during exercise is valuable in timing of
aortic valve surgery in male aortic regurgitation patients.” J Am Soc Echocardiogr
(2010): 387-395.
[31] Forsberg LM, Nylander E, Tamás É. “Exercise echocardiography predicts postoperative
left ventricular remodeling in aortic regurgitation.” Scand Cardiovasc J (2014): 4-12.
[32] Kusunose K, Agarwal S, Marwick TH, Griffin BP, Popović ZB. “Decision making in
asymptomatic aortic regurgitation in the era of guidelines: incremental values of resting
and exercise cardiac dysfunction.” Circ Cardiovasc Imaging (2014): 352-362.
In: Perspectives in Aortic Valve Disease ISBN: 978-1-53618-769-4
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Editor: Giovanni Concistrè © 2020 Nova Science Publishers, Inc.
Chapter 4
ADVANCED IMAGING AND FUNCTIONAL TOOLS FOR
AORTIC VALVE ASSESSMENT: CARDIOVASCULAR
MAGNETIC RESONANCE AND CARDIAC COMPUTED
TOMOGRAPHY ANGIOGRAPHY
Andrea Barison and Alberto Clemente*
Fondazione Toscana Gabriele Moonasterio, Pisa-Massa, Italy
ABSTRACT
Cardiovascular Magnetic Resonance (CMR) and Cardiac Computed Tomography
Angiography (CCTA) provide three-dimensional, high resolution view of the thoracic
aorta, aortic root, aortic valve and the underlying myocardium. In particular, CCTA
represents the reference standard for anatomic assessment of the aortic valve, the
coronary tree and for calcium detection in relation to its submillimetric spatial resolution
with enough temporal resolution to clearly plan interventions.
CMR represents the reference standard for biventricular volume and function
calculation, for flow measurements and for tissue characterization. Both CMR and CCTA
allow a three-dimensional and multiplanar reconstruction of the thoracic aorta and great
vessels. This review encompasses the existing literature regarding the role of CMR and
CCTA in aortic valve disease, including diagnosis, prognosis and follow-up.
Keywords: aortic stenosis, aortic regurgitation, aortic valve, magnetic resonance, computed
tomography
INTRODUCTION
Aortic valve disease shows a relatively high prevalence in the general population,
particularly in the elderly [1]. Crucial to patient management is the early diagnosis and
*
Corresponding Author’s Email: clemente@ftgm.it.
Andrea Barison and Alberto Clemente
56
Spatial resolution
Dimensionality
Temporal resolution
Contrast resolution
Catheter angiography
0.15 mm
2D
1-10 ms
Moderate
CCTA
0.23-0.5 mm
2D/3D
29-175 ms
Moderate/High*
Echocardiography
0.5-2 mm
2D/3D
<10 ms
Low
CMR
1-2 mm
2D/3D
20-50 ms
High
PET
4-8 mm
3D
100-300 ms
High
SPECT
5-15 mm
3D
100-300 ms
High
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correct grading of disease severity, which depends on multiple factors such as the anatomy of
the leaflets, valve hemodynamics and left ventricular (LV) function, in addition to patient
symptoms [2]. Cardiac imaging is necessary not only for early diagnosis, but also for
prognosis, therapeutic management and follow-up. Besides surgical aortic valve replacement
(SAVR), minimally invasive percutaneous interventional techniques, like transcatheter aortic
valve implantation (TAVI), have been recently established as a valid alternative option: a
crucial task of cardiac imaging is to guide clinicians to plan the appropriate time and
techniques of aortic valve treatment.
In this complex clinical scenario, although echocardiography remains the primary
imaging modality for both initial assessment and longitudinal evaluation of aortic valve
disease, cardiovascular magnetic resonance (CMR) and computed tomography (CT) are being
increasingly used in daily clinical practice due to their versatility, which allows a
comprehensive evaluation of the different aspects of valvular disease. CMR is a robust
alternative for aortic valve assessment in patients with a poor acoustic window, and represents
the reference stardard for biventricular volume and function calculation, for flow
measurements and for tissue characterization. Both CMR and CT allow a three-dimensional
and multiplanar reconstruction of the thoracic aorta and great vessels. CT represents the
reference standard for anatomic assessment of the aortic valve, the coronary tree and for
calcium detection (Table 1).
This review encompasses the existing literature regarding the role of CMR and CT in
morphological and functional assessment of aortic valve stenosis and regurgitation, from
disease staging, to surgical/percutaneous interventional planning, to post-operative follow-up.
Moreover, the prognostic implications related to the concomitant presence of myocardial
ischaemia, systolic/diastolic dysfunction or fibrosis will be analysed, with CMR providing a
unique tissue characterization and CT a unique anatomical definition.
Table 1. Technical characteristics of different imaging modalities
CCTA, Cardiac Computed Tomography Angiography, CMR, Cardiac Magnetic Resonance; SPECT, Single-Photon
Emission Computed Tomography; PET, Positron Emission Tomography.
*: High contrast resolution for vascular structures and moderate contrast resolution for myocardial characterization.
AORTIC VALVE MORPHOLOGY
Normal Anatomy
The aortic valve is a trifoliate structure supported by a fibrous skeleton, linked with the
anterior leaflet of the mitral valve. The three valve cusps (left, right and non-coronary) are
thin and symmetric leaflets of fibrous tissue that open uniformly, pushing into their respective
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