Precision of regional wall motion estimates from ultra-low-dose cardiac CT using SQUEEZ
Resting regional wall motion abnormality (RWMA) has significant prognostic value beyond the findings of computed tomography (CT) coronary angiography. Stretch quantification of endocardial engraved zones (SQUEEZ) has been proposed as a measure of regional cardiac function. The purpose of the work reported here was to determine the effect of lowering the radiation dose on the precision of automatic SQUEEZ assessments of RWMA. Chronic myocardial infarction was created by a 2-h occlusion of the left anterior descending coronary artery in 10 swine (heart rates 80–100, ejection fraction 25–57%). CT was performed 5–11 months post infarct using first-pass contrast enhanced segmented cardiac function scans on a 320-detector row scanner at 80 kVp/500 mA. Images were reconstructed at end diastole and end systole with both filtered back projection and using the “standard” adaptive iterative dose reduction (AIDR) algorithm. For each acquisition, 9 lower dose acquisitions were created. End systolic myocardial function maps were calculated using SQUEEZ for all noise levels and contrast-to-noise ratio (CNR) between the left ventricle blood and myocardium was calculated as a measure of image quality. For acquisitions with CNR > 4, SQUEEZ could be estimated with a precision of ± 0.04 (p < 0.001) or 5.7% of its dynamic range. The difference between SQUEEZ values calculated from AIDR and FBP images was not statistically significant. Regional wall motion abnormality can be quantified with good precision from low dose acquisitions, using SQUEEZ, as long as the blood-myocardium CNR stays above 4.
KeywordsMyocardial function CT noise Wall motion abnormality Regional cardiac function SQUEEZ
Funding was provided by National Institutes of Health (Grant Nos. R01-HL64795, R01-HL094610).
Compliance with ethical standards
Conflict of interest
AP and EM have a patent application for SQUEEZ (US 14/350,991). MYC receives institutional research support from Toshiba Medical Systems. Other authors did not report any conflicts.
- 3.Seneviratne SK, Truong QA, Bamberg F et al (2010) Incremental diagnostic value of regional left ventricular function over coronary assessment by cardiac computed tomography for the detection of acute coronary syndrome in patients with acute chest pain: from the ROMICAT trial. Circ Cardiovasc Imaging 3:375–383. https://doi.org/10.1161/CIRCIMAGING.109.892638 CrossRefPubMedPubMedCentralGoogle Scholar
- 4.Schlett CL, Banerji D, Siegel E et al (2011) Prognostic value of CT angiography for major adverse cardiac events in patients with acute chest pain from the emergency department: 2-year outcomes of the ROMICAT trial. JACC Cardiovasc Imaging 4:481–491. https://doi.org/10.1016/j.jcmg.2010.12.008 CrossRefPubMedPubMedCentralGoogle Scholar
- 6.Pourmorteza A, Schuleri KH, Herzka DA et al (2012) Regional cardiac function assessment in 4D CT: comparison between SQUEEZ and ejection fraction. In: 2012 annual international conference of the IEEE engineering in medicine and biology society (EMBC), pp 4966–4969. https://doi.org/10.1109/EMBC.2012.6347107
- 12.Fan Y, Zamyatin AA, Nakanishi S (2012) Noise simulation for low-dose computed tomography. IEEE nuclear science symposium and medical imaging conference (NSS/MIC), pp 3641–3643. https://doi.org/10.1109/NSSMIC.2012.6551836
- 13.Angel E (Toshiba America Medical Systems I AIDR3D Whitepaper. http://medical.toshiba.com/downloads/aidr-3d-wp-aidr-3d
- 15.Behar JM, Pourmorteza A, McVeigh E, Niederer S, Claridge S, Jackson T, Sohal M, Preston R, Carr-White G, Razavi R, Rajani R, CAR (2015) Cardiac computed tomography is a feasible imaging modality for pre procedural planning in patients undergoing upgrade from pacemakers to CRT. Europace 17:v10–v13CrossRefGoogle Scholar
- 17.Schuhbaeck A, Achenbach S, Layritz C et al (2013) Image quality of ultra-low radiation exposure coronary CT angiography with an effective dose < 0.1 mSv using high-pitch spiral acquisition and raw data-based iterative reconstruction. Eur Radiol 23:597–606. https://doi.org/10.1007/s00330-012-2656-2 CrossRefPubMedGoogle Scholar