CLINICAL RESEARCH: CARDIAC IMAGING
Multislice Computed Tomography for Detection of Patients With Aortic Valve Stenosis and Quantification of Severity
Gudrun M. Feuchtner, MD*,*,
Wolfgang Dichtl, MD ,
Guy J. Friedrich, MD,
Mathias Frick, MD,
Hannes Alber, MD,
Thomas Schachner, MD ,
Johannes Bonatti, MD,
Ammar Mallouhi, MD*,
Thomas Frede, MD*,
Otmar Pachinger, MD,
Dieter zur Nedden, MD* and
Silvana Müller, MD
* Clinical Department of Radiology II, Innsbruck Medical University, Innsbruck, Austria
Clinical Department of Cardiology, Innsbruck Medical University, Innsbruck, Austria
Clinical Department of Cardiac Surgery, Innsbruck Medical University, Innsbruck, Austria
Manuscript received January 3, 2005;
revised manuscript received November 2, 2005,
accepted November 15, 2005.
* Reprint requests and correspondence: Dr. Gudrun Maria Feuchtner, Clinical Department of Radiology II, Innsbruck Medical University, Anichstr. 35, A-6020 Innsbruck, Austria (Email: Gudrun.Feuchtner{at}uibk.ac.at).
 |
Abstract
|
|---|
OBJECTIVES: The purpose of this study was to evaluate whether multislice computed tomography (MSCT) provides a reliable, noninvasive imaging modality for identification of patients with degenerative aortic valve stenosis (AS) by quantifying the aortic valve area (AVA) in comparison to the accepted diagnostic standard transthoracic echocardiography (TTE).
BACKGROUND: Management of patients with degenerative AS is based on the severity of disease. The severity of AS in clinical practice is assessed by TTE and classified as mild, moderate, or severe according to the AVA.
METHODS: Forty-six patients were examined with contrast-enhanced, electrocardiogram-gated, 16-row MSCT for the evaluation of the diagnostic accuracy. In 30 patients, quantification of the AVA with MSCT was compared to TTE using the continuity equation with Doppler velocity-time integral for calculation of the AVA.
RESULTS: Sensitivity of MSCT for the identification of patients with degenerative AS was 100%, and the specificity was 93.7%. Thirty of 46 patients had AS determined by TTE. Quantification of AVA by MSCT (mean AVA = 0.94 cm2) in patients with AS showed a good correlation to TTE (r = 0.89; p < 0.001). Bland-Altman plot illustrated good intermodality agreement between the two methods (limits of agreement, 0.20; 0.29).
CONCLUSIONS: Multislice computed tomography may provide an accurate, noninvasive imaging technique for detection of patients with AS and quantification of AVA.
|
Abbreviations and Acronyms
| | AS = aortic stenosis | | AVA = aortic valve area | | CAD = coronary artery disease | | CMR = cardiac magnetic resonance imaging | | CT = computed tomography | | LVOT = left ventricular outflow tract | | MSCT = multislice computed tomography | | TEE = transesophageal echocardiography | | TTE = transthoracic echocardiography |
|
Degenerative aortic valve stenosis (AS) is the second most common cardiovascular disease and has an incidence of 2% to 7% in the Western European and North American populations over 65 years of age (1). Management of patients with AS is based on disease severity, which is usually classified by determination of the aortic valve area (AVA). An AVA >1.5 cm2 indicates mild, an AVA between 1.5 cm2 to 1 cm indicates moderate, and an AVA below 1 cm2 is considered as severe AS according to American College of Cardiology/American Heart Association guidelines (2) in addition to an increased peak transvalvular velocity >2 m/s. Patients with severe AS may require aortic valve surgery even when they are asymptomatic. Currently, AVA is routinely assessed by transthoracic echocardiography (TTE) using the Doppler continuity equation approach. However, TTE may be technically inadequate for some patients, and semi-invasive transesophageal echocardiography (TEE) or cardiac catheterization is required to establish a firm diagnosis.
Sixteen-row multislice computed tomography (MSCT) is a new, noninvasive imaging modality that has already provided new perspectives in the field of cardiac imaging over the past few years. Multislice computed tomography has been shown to be highly accurate for detection of significant coronary artery stenosis >50% (3–6) and coronary bypass graft occlusion (7). Furthermore, MSCT allows a characterization of atherosclerotic plaque morphology (8). However, to date there is little data (9) regarding the value of MSCT in the assessment of valvular pathologies.
The purpose of this study was to assess the clinical accuracy of MSCT in the identification of patients with asymptomatic AS and to evaluate whether quantification of AVA by MSCT correlates with the currently accepted diagnostic standard TTE.
|
Methods
|
|---|
Study population.
A total of 46 patients (10 women and 36 men with a mean age of 69 years [range 45 to 78 years]) were examined between October 2003 and December 2004 with MSCT and TTE. The institutional review board approved the studies on cardiac MSCT in: 1) 30 patients with AS; and 2) 16 patients with known coronary artery disease (CAD) before minimal invasive coronary bypass surgery. Written informed consent was obtained from all patients. Patient exclusion criteria were renal dysfunction, other contraindications for the use of iodine contrast agent (e.g., known allergy), and cardiac arrhythmia.
Computed tomography (CT) examination technique.
Computed tomography data were acquired using a 16-row multislice CT scanner (Sensation 16, Siemens Medical Systems, Forchheim, Germany) with a collimation of 12 x 0.75 mm, a table translation speed of 6.7 mm/s, and a gantry rotation time of 0.42 s. Tube voltage was 120 kV, tube current 300 to 450 mAs, and radiation exposure 6.7 to 13 mSv (10). Electrocardiogram (ECG) dose modulation was not used. Scan direction was craniocaudal during a single inspiratory breath-hold, and the ECG-signal was recorded simultaneously. A bolus of 120 ml non-ionic iodine contrast agent at a concentration of 320 mg/dl (Visipaque, Amersham, Buckinghamshire, United Kingdom) was injected intravenously into an antecubital vein with a 20-gauge cannula at a flow rate of 3 to 4 ml/s using an automated injector (Ulrich Medizintechnik, Ulm, Germany). A fixed scan delay of 25 s was used. A beta-blocker was injected intravenously (1 to 5 mg of metoprololtartrat, Beloc, Schering, Kenilworth, New Jersey) before the examination if the heart rate was >80 beats/min.
CT image reconstruction.
Transaxial slices were generated at increments of 0.6 (effective slice thickness of 1 mm). Further reconstruction parameters were as follows: smooth convolution kernel (B 10 f), image matrix 512 x 512 pixel, field of view 170 to 200 mm. The acquired data set was referenced retrospectively to the simultaneously recorded ECG signal. The reconstruction window was positioned within mid-to-late systole corresponding to ejection phase in concordance with T-wave (Fig. 1). The time point of the first image reconstruction cycle was calculated depending on heart rate by subtracting the time of isovolumetric contraction (50 ms) from the duration of cardiac cycle. Then, further reconstruction cycles were generated during the entire mid-late systole at every 50 ms in order to identify the phase of maximal aortic valve opening. Three to 6 cycles were necessary depending on the heart rate (e.g., the duration of mid-late systole is 385 ms at 50 beats/min vs. 319 ms at 80 beats/min).
View larger version (27K):
[in this window]
[in a new window]
|
Figure 1 Mid-late systolic multislice computed tomography image reconstruction with retrospective electrocardiogram-gating: within mid-late systole (ejection phase: 2 and 3), aortic valve is opened. Image reconstruction window (R) was positioned within mid-late systole approximately corresponding to T-wave. The time point of reconstruction window was estimated by subtracting the time of isovolumetric contraction (1) (0.05 s) from overall duration of cardiac cycle dependent on heart rate. bpm = beats/min.
|
|
CT image analysis.
Images were transferred to a dedicated off-line computed workstation (Leonardo, Siemens Medical Systems, Forchheim, Germany) and reconstructed using multiplanar reformation and volume rendering technique. Three different views, a left coronal oblique view (Fig. 2A), left sagittal oblique (Fig. 2B) view, and several cross-sectional transversal levels (Fig. 2C) ranging from the top of the leaflets to the infundibulum (Fig. 3), were generated for aortic valve analysis. Aortic valve area was measured in all transverse planes. The smallest measurable AVA value in cm2 was regarded as an effective AVA. One experienced reviewer (G.F.) circled the effective AVA with a digital caliper (Fig. 2C) blinded to TTE measurement of the AVA. A second reader (D.W.) (not blinded) circled the AVA independently in order to calculate the interobserver variability. For calculation of the diagnostic accuracy, CT images of the patients from the second study pool (CAD before surgery) were blindly analyzed by both readers. The aortic valve image quality was graded on a 5-point scale in consensus reading by two observers (G.F. and W.D.): grade 1 = excellent (sharp delineation of AVA, no artifact); 2 = good (good delineation of AVA, minimal artifact not affecting AVA); 3 = mediocre (minimal artifact at AVA level, acceptable delineation of AVA); 4 = poor (disrupted delineation of AVA, moderate artifact); 5 = insufficient, non-diagnostic image quality (no delineation of AVA, severe artifact).
View larger version (70K):
[in this window]
[in a new window]
|
Figure 2 Three-dimensional multislice computed tomography image reconstruction: left coronal oblique long axis (A), left sagittal oblique short axis (B), and cross-sectional transversal (C) in a patient with severe aortic stenosis and heavy calcifications (C). Black arrow pointing at aortic valve orifice (O). White arrow denotes the eccentric systolic jet (J) created from accelerated blood flow (white) through aortic valve orifice. AA = ascending aorta; LV = left ventricle. The white line indicates the plane of image C at which aortic valve area was circled with a digital calliper and computed in cm2.
|
|
View larger version (120K):
[in this window]
[in a new window]
|
Figure 3 Quantification of aortic valve area (AVA) ("planimetry"): AVA was reconstructed at three cross-sectional transversal levels (A to C). The smallest AVA value was taken for effective AVA. AA = ascending aorta; LV = left ventricle.
|
|
TTE.
All measurements were performed using a standard ultrasound system (Acuson Sequoia 256, Acuson-Siemens Medical Systems, Malvern, Pennsylvania) equipped with a 3.5/1.75-MHz transducer by an experienced class III observer (S.M.). Doppler flow data were acquired from the left ventricular outflow tract (LVOT) and included LVOT velocity measurement using pulsed-wave Doppler and LVOT diameter. The peak transvalvular velocity was measured in all patients. A peak transvalvular velocity >2 m/s was considered as the diagnostic cutoff for the detection of patients with AS. Additionally, the AVA was calculated using continuity equation approach with Doppler velocity-time integral according to Dumesnil (11) exclusively in patients who had an increased peak transvalvular velocity.
Statistical analysis.
The sensitivity, the specificity, the positive predictive value, and the negative predictive value of MSCT for identification of patients with AS was calculated. Statistical analysis was performed using SSPS software (version 8.0, SPSS Inc., Chicago, Illinois). The correlation between AVA measured by MSCT and TTE was determined by linear regression analysis. A two-tailed probability value <0.05 was considered statistically significant. Bland Altman analysis (12) was performed in order to evaluate intermodality agreement by plotting the AVA difference between MSCT and TTE against AVA averages. The mean of the difference with a bias of ±1.96 SD denotes the limits of agreement. Interobserver variability of AVA between two independent readers was computed as a percentage of the mean differences between the corresponding observations divided by the average of all observations.
|
Results
|
|---|
Thirty of the 46 patients had AS as determined by TTE. The sensitivity of MSCT for detection of patients with degenerative AS was 100% (30 of 30) (95% confidence interval [CI]: 88.3 to 100), and the specificity was 93.7% (15 of 16) (95% CI: 69.7 to 99.0). One patient was false-positive on MSCT. The positive predictive value was 97% (95% CI: 83.8 to 99.4), and the negative predictive value was 100% (95% CI: 79.6 to 100). Table 1 shows the AVA values for each patient with degenerative AS. Figure 4 demonstrates the AVA during mid-late systole by MSCT. Linear regression analysis shows a good correlation between AVA quantified by MSCT and TTE (r = 0.89; p < 0.001; 95% CI 0.78 to 0.95) in patients with AS (Fig. 5). The Bland-Altman plot (Fig. 6) implies a good intermodality concordance placing 27 of 30 patients between the limits of agreement (0.29; –0.20) and suggests a slight overestimation of AVA (+0.04 cm2) by MSCT compared to TTE. Interobserver variability of AVA by MSCT was mean 4.6% (absolute 0.48 cm2 ± 0.03 SD). Image quality graded on a 5-point scale was excellent (n = 29), good (n = 14), and mediocre (n = 3). The mean heart rate in our study population was 60 beats/min ± 10.6 SD (range 40 to 81 beats/min). A beta-blocker was administered to 4 of the 46 patients. A right ventricular pacemaker was present in 4 of the 46 patients, but metal artifacts from the wires did not extend to the aortic valve level and did not hamper image quality of the valve. Examination time for the patient ranged between 10 and 15 min, and the mean time required for post-processing, including three-dimensional image reconstruction of aortic valve, was 8 to 15 min. A bicuspid valve was found in 2 of the 46 patients by MSCT (Figs. 4E to 4H); these were not seen by TTE (Table 1). Patients with tricuspid valves are shown in Figures 4A to 4D and Figure 7.
View larger version (97K):
[in this window]
[in a new window]
|
Figure 4 Aortic valve stenosis, diastole versus systole, bicuspid versus tricuspid valve: by using retrospective electrocardiogram-gating, split diastolic and systolic multislice computed tomography image reconstruction is feasible. The aortic valve of four patients with aortic stenosis is shown closed during diastole at panels A, C, E, and H (left) and open during systole at panels B, D, F, and G (right) allowing planimetry of aortic valve area (AVA) (tricuspid [A to D] valve in two patients vs. bicuspid [E to H] valve morphology in two patients). Note the characteristic "fish-mouth" feature of bicuspid aortic valve within systole (H). White arrows pointing at valve calcifications; black arrows denote AVA (F). Different post-processing techniques were applied: multiplanar reformation (A to F and H) and slab volume rendering technique (G); LCC = left coronary cusp; R = right coronary ostium; RCC = right coronary cusp. For accompanying videos for panels A and B, and panel G, please see the Appendix.
|
|
View larger version (16K):
[in this window]
[in a new window]
|
Figure 5 Linear regression analysis illustrates a good correlation of aortic valve area (AVA) (in cm2) derived by multislice computed tomography (MSCT) (r = 0.89; p < 0.001) compared to transthoracic echocardiography (TTE).
|
|
View larger version (20K):
[in this window]
[in a new window]
|
Figure 6 Bland-Altman plot demonstrates a good intermodality agreement between multislice computed tomography (MSCT) and transthoracic echocardiography (TTE) with a slight overestimation of aortic valve area (AVA) by MSCT (+0.04 cm2).
|
|
View larger version (87K):
[in this window]
[in a new window]
|
Figure 7 Aortic valve with volume rendering technique (VRT) (A) versus multiplanar reformation (B): aortic valve area appeared split and was calculated by the addition of both area 1 (A1) and area 2 (A2). White arrow denotes aortic valve calcification, which can be displayed better with VRT. LCC = left coronary cusp; NCC = non-coronary cusp; RCC = right coronary cusp.
|
|
|
Discussion
|
|---|
This study shows that MSCT accurately identifies patients with AS and allows quantification of AVA with a good correlation to the current diagnostic standard TTE. Identification of patients with degenerative AS using MSCT has not been previously reported.
Cardiac MSCT.
The application of CT to cardiac imaging has long been limited by insufficient temporal resolution. However, the introduction of 16-row MSCT scanners with high gantry rotation time (>0.42 s) in 2002 has improved temporal resolution to 105 to 250 ms and the spatial resolution to 0.5 x 0.5 x 0.6 mm3 (13). In addition, advanced technical features such as retrospective ECG-gating offer image reconstruction at any time during the cardiac cycle, which permits a dynamic display of heart motion ("cine CT" with image reconstruction at every 10% of the RR-interval). Thus, the maximal opening of the aortic valve during mid-late systole can be identified, and quantification of AVA is possible. Mid-late systole represents a phase with relatively less cardiac motion and has been shown to be adequate for image acquisition (14).
Value of echocardiography.
Currently, TTE is widely used for primary diagnostic evaluation of AS; TTE is real-time imaging basically relying on dynamic flow parameters by using velocity-time integral for the calculation of the AVA. Potential limitations associated with the use of the continuity equation include difficulty in accurately measuring the LVOT diameter and estimating the maximal velocity of the LVOT and the aorta before flow acceleration. Furthermore, low cardiac output (2,15), concomitant aortic valve regurgitation (15,16), severe valve calcifications, and other unusual anatomic configurations impairing the echocardiographic window may also limit TTE results. Alternatively, TEE or cardiac catheterization may be used for further diagnostic assessment of the severity of AS; TEE determination of AVA is planimetric in its approach. Transesophageal echocardiography is semi-invasive, and caution is needed because of shadowing and reverberation artifacts from the calcified leaflets. The non-planar aortic valve anatomy may also lead to errors. Indeed, its noninvasive character makes MSCT an attractive alternative imaging technique. Compared to TTE, overall physician time with MSCT would be roughly similar, approximately 20 to 30 min.
Value of TEE and cardiac magnetic resonance imaging CMR.
Transesophageal echocardiography planimetry (17) and CMR (18) have been shown to provide a reproducible measurement of the AVA. In contrast to MSCT, slice tracking is not possible with two-dimensional cine CMR because the correct mid-to-end systolic position has to be identified in a longitudinal view in order to avoid being out of plane. By using MSCT, any plane at any level ("slice tracking") during the cardiac cycle can be reconstructed retrospectively.
Clinical applications of MSCT.
Currently, a routine clinical implementation of MSCT for diagnostic evaluation of AS cannot be recommended. However, MSCT may play a role in patients in whom a direct measurement of AVA is important but cannot be obtained by TTE. Multislice computed tomography can also be applied in clinical practice to detect asymptomatic AS in patients who undergo coronary MSCT angiography, for example in patients with suspected CAD. Detection of asymptomatic patients is desirable because patients with asymptomatic, severe AS may require short-term follow-up examinations or surgery.
Study limitations.
The incidence of true disease was very high (30 of 46; 65%) in our study population because the patients were assigned to cardiac MSCT (i.e., before cardiac surgery [e.g., minimal invasive coronary bypass graft surgery or valve surgery]). Therefore, our study population is not representative of the type of population evaluated for AS by TTE in an outpatient setting. Thus, the high sensitivity portrays a level of accuracy that is unlikely to be achievable in a broad spectrum of patients. Further, a very smooth convolution kernel (B 10 f) was used for image reconstruction that might be occasionally inappropriate for the simultaneous evaluation of calcifying coronary arteries. Alternatively, a medium resolution kernel (B 25 f, B 30 f) can be applied for both coronary artery and aortic valve analysis.
Limitations of MSCT.
Patients not in sinus rhythm, for example persistent atrial fibrillation, cannot be assessed because ECG-gating requires heart rate regularity. Heart rate should be below 80 beats/min to avoid motion artifacts from the residual cardiac motion. Therefore, a beta-blocker may be given to selected patients, but should be administered with great care to patients with severe AS. Radiation exposure ranges between 6.7 to 10.9 mSv for male patients and 8.1 to 13 mSv for female patients (10), which is approximately in the range of cardiac catherization (2.7 to 15.3 mSv) depending on patient and procedure (19) and is significantly lower than compared with a myocardial single photon emission computed tomography (20 mSv) (20). Electrocardiogram dose modulation, which clearly reduces the radiation exposure about 45% to 48% (21), is not recommended in this setting because the tube output is lowered exclusively within systole, thus hampering image quality. Iodine contrast agents cannot be administered to patients with renal dysfunction, known allergy, and untreated hyperthyreosis.
Conclusions.
Sixteen-MSCT provides an accurate, noninvasive imaging modality for identification of patients with AS. We do not advocate MSCT as a primary diagnostic imaging technique in clinical practice because currently used TTE is accurate, safe, quick, and cost-effective. Multislice computed tomography could be used alternatively in patients in whom TTE is inadequate and in patients with suspected CAD who undergo coronary MSCT angiography for the detection of concomitant, asymptomatic AS.
|
Appendix
|
|---|
For accompanying videos for Figures 4A and 4B, and 4G, please see the online version of this article.
|
References
|
|---|
1. Steward BF, Siscovick D, Lind BK, et al. Clinical factors with calcific aortic valve disease J Am Coll Cardiol 1997;29:630-634.[Abstract]2. Bonow R, Carabello B. Guidelines for the management of patients with valvular heart disease. ACC/AHA guidelines Circulation 1998;98:1949-1984.[Free Full Text] 3. Hoffmann M, Shi H, Schmitz B, et al. Noninvasive coronary angiography with multislice computed tomography JAMA 2005;293:2471-2478.[Abstract/Free Full Text] 4. Mollet NR, Cademartiri F, Krestin GP, et al. Improved diagnostic accuracy with 16-row multi-slice computed tomography coronary angiography J Am Coll Cardiol 2005;45:128-132.[Abstract/Free Full Text] 5. Kuettner A, Kopp A, Schroeder S, et al. Diagnostic accuracy of multidetector computed angiography in patients with angiographically proven coronary artery disease J Am Coll Cardiol 2004;43:831-839.[Abstract/Free Full Text] 6. Nieman K, Cademartiri F, Pattynama P, et al. Reliable noninvasive coronary angiography using sub-millimeter multislice spiral CT Circulation 2002;106:2051-2054.[Abstract/Free Full Text] 7. Nieman K, Pattynama PMT, Rensing BJ, et al. Evaluation of patients after coronary artery bypass surgeryangiographic assessment of grafts and coronary arteries. Radiology 2003;229:749-756.[Abstract/Free Full Text] 8. Leber AW, Knez A, Becker A, et al. Accuracy of multidetector spiral computed tomography in identifying and differentiating the composition of coronary atherosclerotic plaquesa comparative study with intracoronary ultrasound. J Am Coll Cardiol 2004;43:1241-1247.[Abstract/Free Full Text] 9. Willmann JK, Weishaupt D, Lachat M, et al. Electrocardiographically gated multi-detector CT for assessment of valvular morphology and calcifications in aortic stenosis Radiology 2002;225:120-128.[Abstract/Free Full Text] 10. Hunold P, Vogt FM, Schmermund A, et al. Radiation exposure during cardiac CTeffective doses at multi-detector row CT and electron-beam CT. Radiology 2003;226:145-152.[Abstract/Free Full Text] 11. Dumesnil JG, Honos GN, Lemieux A, et al. Validation and application of indexed aortic prosthetic valve areas calculated by Doppler echocardiography J Am Coll Cardiol 1990;16:637-643.[Abstract] 12. Bland JM, Altman DG. Statistical methods for assessing the agreement between two methods of clinical measurement Lancet 1986;1:307-310.[CrossRef][Web of Science][Medline] 13. Flohr T, Bruder H, Stierstorfer K, et al. New technical developments in multislice CT, part 2. Sub-millimeter 16-slice scanning and increased gantry rotation speed for cardiac imaging(in German) Rofo Fortschr Geb Roentgenstr 2002;174:1023-1027. 14. Herzog C, Nasreddin A, Balzer J, et al. Heart-rate-adapted image reconstruction in multidetector-row cardiac CTinfluence of physiological and technical prerequisite on image quality. Eur Radiol 2002;12:2670-2678.[Web of Science][Medline] 15. Danielsen R, Norderehaug JE, Vik-Mo H, et al. Factors affecting Doppler echocardiographic valve area assessment in aortic stenosis Am J Cardiol 1989;63:1107-1111.[CrossRef][Web of Science][Medline] 16. Berglund H, Kim CJ, Nishioka T, et al. Influence of ejection fraction and valvular regurgitation on accuracy of aortic valve area determination Echocardiography 2001;18:65-72.[Medline] 17. Okura H, Yoshida K, Hozumi T, et al. Planimetry and transthoracic two-dimensional echocardiography in noninvasive assessment of aortic valve area in patients with valvular aortic stenosis J Am Coll Cardiol 1997;30:753-759.[Abstract] 18. John AS, Dill T, Brandt RR, et al. Magnetic resonance to assess the aortic valve area in aortic stenosishow does it compare to current diagnostic standard. J Am Coll Cardiol 2003;42:519-526.[Abstract/Free Full Text] 19. Stisova V. Effective dose to patient during cardiac interventional procedures Radiat Prot Dosimetry 2004;111:271-274.[Abstract/Free Full Text] 20. Picano E. Economic and biological costs of cardiac imaging Cardiovasc Ultrasound 2005;25:13. 21. Jakobs TF, Becker CR, Ohnesorge B, et al. Multislice helical CT of the heart with retrospective ECG gatingreduction of radiation exposure by ECG-controlled tube current modulation. Eur Radiol 2002;12:1081-1086.[CrossRef][Web of Science][Medline]
This article has been cited by other articles:
|
|
|
|
 
P. Schoenhagen, E. M. Tuzcu, S. R. Kapadia, M. Y. Desai, and L. G. Svensson
Three-dimensional imaging of the aortic valve and aortic root with computed tomography: new standards in an era of transcatheter valve repair/implantation
Eur. Heart J.,
September 1, 2009;
30(17):
2079 - 2086.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
G. M. Feuchtner, P. Stolzmann, W. Dichtl, T. Schertler, J. Bonatti, H. Scheffel, S. Mueller, A. Plass, L. Mueller, T. Bartel, et al.
Multislice computed tomography in infective endocarditis comparison with transesophageal echocardiography and intraoperative findings.
J. Am. Coll. Cardiol.,
February 3, 2009;
53(5):
436 - 444.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. M. LaBounty, B. Sundaram, P. Agarwal, W. A. Armstrong, E. A. Kazerooni, and E. Yamada
Aortic Valve Area on 64-MDCT Correlates with Transesophageal Echocardiography in Aortic Stenosis
Am. J. Roentgenol.,
December 1, 2008;
191(6):
1652 - 1658.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
G. M. Feuchtner, W. Dichtl, S. Muller, D. Jodocy, T. Schachner, A. Klauser, and J. O. Bonatti
64-MDCT for Diagnosis of Aortic Regurgitation in Patients Referred to CT Coronary Angiography
Am. J. Roentgenol.,
July 1, 2008;
191(1):
W1 - W7.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. Schroeder, S. Achenbach, F. Bengel, C. Burgstahler, F. Cademartiri, P. de Feyter, R. George, P. Kaufmann, A. F. Kopp, J. Knuuti, et al.
Cardiac computed tomography: indications, applications, limitations, and training requirements: Report of a Writing Group deployed by the Working Group Nuclear Cardiology and Cardiac CT of the European Society of Cardiology and the European Council of Nuclear Cardiology
Eur. Heart J.,
February 2, 2008;
29(4):
531 - 556.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
L. F. Tops, S. C. Krishnan, J. D. Schuijf, M. J. Schalij, and J. J. Bax
Noncoronary applications of cardiac multidetector row computed tomography.
J. Am. Coll. Cardiol. Img.,
January 1, 2008;
1(1):
94 - 106.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. Burgstahler and S. Schroeder
Magnetic resonance imaging versus computed tomography for the detection of coronary stenosis: do we really have to focus on "stenoses"?
Heart,
November 1, 2007;
93(11):
1322 - 1324.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J.-P. Laissy, D. Messika-Zeitoun, J.-M. Serfaty, V. Sebban, E. Schouman-Claeys, B. Iung, and A. Vahanian
Comprehensive evaluation of preoperative patients with aortic valve stenosis: usefulness of cardiac multidetector computed tomography
Heart,
September 1, 2007;
93(9):
1121 - 1125.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A.-C. Pouleur, J.-B. le Polain de Waroux, A. Pasquet, J.-L. J. Vanoverschelde, and B. L. Gerber
Aortic Valve Area Assessment: Multidetector CT Compared with Cine MR Imaging and Transthoracic and Transesophageal Echocardiography
Radiology,
September 1, 2007;
244(3):
745 - 754.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
G. M. Feuchtner, S. Muller, J. Bonatti, T. Schachner, C. Velik-Salchner, O. Pachinger, and W. Dichtl
Sixty-Four Slice CT Evaluation of Aortic Stenosis Using Planimetry of the Aortic Valve Area
Am. J. Roentgenol.,
July 1, 2007;
189(1):
197 - 203.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. Goland, A. Trento, K. Iida, L. S C Czer, M. De Robertis, T. Z Naqvi, K. Tolstrup, T. Akima, H. Luo, and R. J Siegel
Assessment of aortic stenosis by three-dimensional echocardiography: an accurate and novel approach
Heart,
July 1, 2007;
93(7):
801 - 807.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
Other articles noted
Evid. Based Med.,
April 1, 2007;
12(2):
63 - 64.
[Full Text]
[PDF]
|
|
|
|
|
|
|
Authors/Task Force Members, A. Vahanian, H. Baumgartner, J. Bax, E. Butchart, R. Dion, G. Filippatos, F. Flachskampf, R. Hall, B. Iung, et al.
Guidelines on the management of valvular heart disease: The Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology
Eur. Heart J.,
January 26, 2007;
(2007)
ehl428v1.
[Full Text]
[PDF]
|
|
|
|
|
|
|
G. M. Feuchtner, W. Dichtl, and S. Muller
Reply
J. Am. Coll. Cardiol.,
December 5, 2006;
48(11):
2354 - 2354.
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. Veyrat
Physiologic Timing for Objective Checking of Instantaneous Maximal Aortic Stenotic Area
J. Am. Coll. Cardiol.,
December 5, 2006;
48(11):
2353 - 2353.
[Full Text]
[PDF]
|
|
|
|
|
|
|
H. Bamgartner
Is there a role for multislice computed tomography in aortic stenosis?
Eur. Heart J.,
December 2, 2006;
27(24):
2923 - 2924.
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. Lavi and S. Lavi
Coronary artery imaging with 64-slice computed tomography from cardiac surgical perspective
Eur. J. Cardiothorac. Surg.,
November 1, 2006;
30(5):
813 - 814.
[Full Text]
[PDF]
|
|
|
|
Top
Abstract
Methods