Wertigkeit der kardialen Mehrschicht-Spiral-CT zur Beurteilung der degenerativen Aortenklappenstenose: Vergleich zur Echokardiographie

Diagnostic and Prognostic Performance of Aortic Valve Calcium Score with Cardiac CT for Aortic Stenosis: A Meta-Analysis

PURPOSE

To evaluate the diagnostic and prognostic performance of the aortic valve calcium score (AVCS) with the Agatston method using CT in aortic stenosis (AS) and to assess mean AVCS according to AS severity.

MATERIALS AND METHODS

In this meta-analysis, PubMed, Embase, and Cochrane were searched from January 1, 1980, to December 31, 2020, for studies reporting sensitivity and specificity of AVCS using CT for severe AS, mean AVCS in severe and nonsevere AS, and/or hazard ratios for all-cause mortality in AS. Data were pooled using random effect models and meta-analysis software.

RESULTS

Twelve studies (six diagnostic, three prognostic, and 10 reporting mean AVCS by AS severity) were included for analysis. A total of 4101 patients (2255 with severe AS) were described in these 12 studies. Pooled sensitivity and specificity were 82% (95% CI: 80, 84) and 78% (95% CI: 75, 81), respectively. Pooled mean AVCS were 3219 (95% CI: 2795, 3643) for severe AS, compared with 1252 (95% CI: 863, 1640) for nonsevere AS, 1808 (95% CI: 1163, 2452) for moderate AS, and 584 (95% CI: 309, 859) for mild AS. Pooled hazard ratio for AVCS as a binary threshold to predict mortality was 2.11 (95% CI: 1.11, 4.12).

CONCLUSION

AVCS had moderate to high sensitivity and specificity for identifying severe AS and was also a useful prognostic imaging marker in AS. Mean AVCS categorized by AS severity may help guide clinical management.Keywords CT, Aortic Valve, Valves, Meta-Analysis© RSNA, 2021.

Pertinent reportable incidental cardiac findings on chest CT without electrocardiography gating: review of 268 consecutive cases

BACKGROUND

Pertinent reportable cardiac findings on non-electrocardiography (ECG)-gated chest CT examinations have become easier to detect given recent advancements in multidetector CT technology. However, those findings are easily overlooked on routine chest CT without ECG gating given residual inherent cardiac motion artifact and non-cardiac indications.

PURPOSE

To describe and quantify the types of pertinent reportable cardiac findings that can be detected on chest CT examinations without ECG gating and evaluate how often they were reported.

MATERIAL AND METHODS

Two radiologists retrospectively reviewed (blinded to the original interpretation) 268 consecutive routine adult chest CT examinations without ECG gating for the presence of pertinent reportable cardiac findings. Retrospective interpretations were then compared with the original radiological reports.

RESULTS

One hundred and sixty-three patients (61%) had pertinent reportable cardiac findings. The findings encountered included: coronary artery disease (n = 131; 80.0%), coronary artery bypass grafts (n = 10; 6.1%), left ventricular aneurysm (n = 1; 0.6%), valve calcification (n = 131; 80.0%), valve repair/replacement (n = 5; 3.1%), pericardial effusion (n = 33; 20.2%), left atrial appendage thrombus (n = 1; 0.6%), cardiac mass (n = 1; 0.6%), and cardiac chamber enlargement (n = 29; 17.8%). On the original radiological reports 22.3% of the pertinent reportable cardiac findings, detected by the two radiologists retrospectively, were not reported.

CONCLUSION

Detection of pertinent reportable cardiac findings on routine chest CT examinations without ECG gating is possible. The high volume of chest CT examinations without ECG gating represents an opportunity for radiologists to comment on the presence or absence of cardiac disease which may influence future clinical decisions.

Cardiac CT: coronary arteries and beyond

Multi-detector-row computed tomography (MDCT) has emerged as a rapidly developing method for non-invasive imaging of the heart. An understanding of ECG synchronization, contrast material administration, patient preparation and image post-processing is needed to optimize image quality. The basic technical principles and essentials of these technical basics are described here. Correctly applied cardiac MDCT allows imaging of the coronary arteries including coronary anatomy and stenosis detection. The same is true for evaluation of coronary artery bypass grafts and, to some extent, coronary artery stents. While quantification of total calcified plaque burden has been long established, coronary MDCT allows assessing plaque morphology and constitution. Recent approaches go beyond the coronaries and include evaluation of left ventricular function at rest and myocardial viability. In combination with experimental approaches for assessing aortic valve function and myocardial perfusion imaging, cardiac MDCT offers the potential for a comprehensive examination of the heart using a single breath-hold examination.

Prevalence and Clinical Importance of Aortic Valve Calcification Detected Incidentally on CT Scans: Comparison with Echocardiography

PURPOSE

To evaluate retrospectively the prevalence and grade of aortic valve calcification incidentally detected on chest multi-detector row computed tomographic (CT) scans and to compare the grade of calcification with the severity of aortic valve disease as assessed with echocardiography.

MATERIALS AND METHODS

Patient informed consent was waived by the institutional board on medical ethics that approved this study. The authors identified 402 patients (231 men and 171 women; mean age, 62.5 years +/- 12.1) of 1820 patients who underwent chest multi-detector row CT between July 2001 and August 2004 and also underwent echocardiography. Aortic valve calcification at multi-detector row CT was visually graded on a scale ranging from 0 to 4 (0 = no calcification, 4 = severe calcification). CT findings were correlated with hemodynamic data obtained at echocardiography. Patients without aortic stenosis were compared with patients with aortic stenosis. The Student t test, Spearman correlation coefficient, chi(2) analysis, and an unweighted kappa test were used to compare results.

RESULTS

Aortic valve calcification was noted on multi-detector row CT scans in 72 of the 402 patients (18%). Twelve of 20 patients (60%) with grade 3 or grade 4 calcification on CT scans had aortic stenosis at echocardiography, compared with only nine of 382 patients (2.4%) with grade 0-2 calcification (P < .001). Significant correlations were observed between the grade of aortic valve calcification and the echocardiographically determined mean (r = 0.45, P = .03) and peak transvalvular gradient (r = 0.47, P = .03). There was substantial agreement between the grade of valve calcification at multi-detector row CT and the severity of aortic valve disease at echocardiography (kappa = 0.67).

CONCLUSION

Aortic valve calcification was an incidental finding on 18% of multi-detector row CT scans. The grade of aortic valve calcification is correlated with the hemodynamic severity of aortic valve disease as determined with echocardiography.

Aortic Stenosis: Comparative Evaluation of 16–Detector Row CT and Echocardiography

PURPOSE

To prospectively evaluate whether planimetric measurements of aortic valve area (AVA) with 16-detector row computed tomography (CT) allow classification of aortic stenosis (AS).

MATERIALS AND METHODS

The study had institutional review board approval; patients gave informed consent. Twenty patients (11 men, nine women; mean age, 63 years) with AS and 20 patients (10 men, 10 women; mean age, 65 years) without underwent transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), and retrospectively electrocardiographically gated 16-detector row CT. Twenty CT data sets were reconstructed in 5% steps of R-R interval; data analysis was performed with four-dimensional software. Maximum AVA in systole planimetrically measured with CT (AVA(CT)) was compared with AVA planimetrically measured with TEE (AVA(TEE)), AVA calculated with the continuity equation and TTE (AVA(TTE)), and transvalvular pressure gradients determined with the Bernoulli equation and TTE. Correlations among AVA(CT), AVA(TTE), AVA(TEE), and transvalvular pressure gradients were tested with bivariate regression analysis; agreement between methods was assessed with the Bland-Altman method.

RESULTS

In patients without AS, mean AVA(CT) was 3.56 cm2 +/- 0.66 and mean AVA(TEE) was 3.43 cm2 +/- 0.69. In patients with AS, mean AVA(CT) was 0.89 cm2 +/- 0.35; mean AVA(TEE), 0.86 cm2 +/- 0.35; and mean AVA(TTE), 0.83 cm2 +/- 0.33. Mean transvalvular pressure gradient was 51 mm Hg +/- 22. Significant correlations were present between AVA(CT) and AVA(TEE) (r = 0.99, P < .001), AVA(CT) and AVA(TTE) (r = 0.95, P < .001), and AVA(CT) and transvalvular pressure gradients (r = -0.74, P < .01). Mean differences were -0.08 cm2 (limits of agreement: -0.32, 0.16) for AVA(CT) versus AVA(TEE) and 0.06 cm2 (limits of agreement: -0.15, 0.26) for AVA(CT) versus AVA(TTE).

CONCLUSION

Planimetric measurements of AVA with retrospectively electrocardiographically gated 16-detector row CT allow classification of AS that is similar to that achieved with measurements by using echocardiographic methods.

Variability of Aortic Valve Calcification Measurement With Multislice Spiral Computed Tomography

OBJECTIVES

We sought to assess the variability of aortic valve calcifications (AVCs) regarding the reconstruction window at different heart phases using multislice-spiral computed tomography.

MATERIALS AND METHODS

A total of 46 patients (26 men; mean age. 65 years) underwent AVC scoring with multislice-spiral computed tomography (12 x 0.75 mm, 120 kV, 133 mAseff). Image reconstruction was performed every 10% of the RR-interval (0-90%). AVC was quantified using Agatston score, calcium volume, and calcium mass. Images were assessed for least motion artifacts. Coefficients of variation and Wilcoxon test were calculated.

RESULTS

AVC scores are lowest at 60% and highest at 0% of the RR-interval (P < 0.001). Mean coefficients of variation were 36.2% (Agatston score), 38.7% (calcium volume), and 32.9% (calcium mass). At 60% (50-70%). minimal motion artifacts and the lowest variability of the scores were found.

CONCLUSIONS

AVC scores show large variability depending on the point of image reconstruction. Diastolic image reconstruction at 60% of the RR-interval is recommended.

Dynamic Cine Mode Imaging of the Normal Aortic Valve Using 16-Channel Multidetector Row Computed Tomography

BACKGROUND

We investigated the feasibility and image quality of dynamic cine-mode imaging of the normal aortic valve using multidetector row computed tomography (MDCT).

MATERIALS AND METHODS

We acquired contrast-enhanced retrospectively echocardiography (ECG)-gated cardiac MDCT datasets of 35 patients (mean age, 62 years; range, 53-77) who received a transoesophageal echocardiography (TOE) precedent to cardiac bypass graft surgery. Twenty data sets in 5% steps of the R-R interval were reconstructed, and data analysis was performed using a 4D software. Read-out of the MDCT data was performed in parallel and perpendicular planes, similar to TOE standard planes, by 2 independent, blinded readers using a 4-point Likert scale (best score: 4) for the following parameters: image quality of the aortic valve components, contrast media enhancement, contrast media inflow related artifacts, and ECG gating-related artifacts. The aortic valve area (AVA) was measured planimetrically and was compared between TOE and MDCT.

RESULTS

The best phase for assessing the open valve using MDCT was at 5% and the closed valve at 65% of the cardiac cycle. The mean image quality scores for cine-mode MDCT ranged between 3.26 and 3.75, with inter-reader agreements ranging between good (kappa = 0.723) and excellent (kappa = 1.00). They did not differ significantly from TOE scores for assessment of the closed and open valve. In transitional phases (close-to-open and open-to-close) TOE performed significantly better when compared with static MDCT images, whereas no significant difference was present between cine-mode presentation of MDCT and TOE. Planimetric AVA measurements correlated significantly between TOE and MDCT (Pearson correlation coefficient, r = 0.96; P < 0.0001). Contrast media inflow-related and ECG gating related artifacts were rated as slightly compromising (scores 3.24 and 3.21).

CONCLUSION

Retrospectively ECG-gated MDCT offers a noninvasive, accurate, and dynamic imaging method for quantitative and qualitative evaluation of the normal aortic valve allowing determination of morphology and function throughout the cardiac cycle. Further studies regarding assessment of diseased valves are necessary.

Calcium scoring of aortic valve calcification in aortic valve stenosis with a multislice computed tomography scanner: non-enhanced versus contrast-enhanced studies

PURPOSE

Previous studies have shown a positive correlation between amount of aortic valve calcification (AVC) and degree of aortic valve stenosis (AVS). We have investigated whether calcium scoring of AVC from contrast-enhanced images is reliable.

MATERIAL AND METHODS

Nineteen patients with suspected AVS underwent retrospectively ECG-gated multislice computed tomography (MSCT). Standardized scan protocols were applied prior to (120 KV, 133 mAseff) and after (120 KV, 500 mAseff) the administration of non-ionic contrast material. Image reconstruction was performed at 60% of the RR interval (slice thickness 3 mm, reconstruction increment 2 mm). AVC was quantified using Agatston score and calcium mass. The number of lesions was calculated. All nonenhanced images were scored using thresholds of 130 HU and 350 HU. Contrast-enhanced images were assessed with a threshold of 350 HU exclusively.

RESULTS

Fifteen patients with AVCs were included in the statistical analysis. The mean Agatston score (calcium mass) in non-enhanced images was 2888.4 +/- 2844.4 (694.2 mg +/- 869.3 mg). Altering the threshold from 130 HU to 350 HU led to a 58.2% (30.5%) decrease in the AVC score (P values < 0.001). Contrast-enhanced images showed an increased Agatston score (calcium mass) of 56.2% (33.5%) compared to non-enhanced images (P values <0.05) with the same threshold of 350 HU.

CONCLUSION

Quantification of AVC from contrast-enhanced images is not reliable, as contrast material simulates calcification.