Precision of regional wall motion estimates from ultra-low-dose cardiac CT using SQUEEZ

  • Amir PourmortezaEmail author
  • Noemie Keller
  • Richard Chen
  • Albert Lardo
  • Henry Halperin
  • Marcus Y. Chen
  • Elliot McVeigh
Original Paper


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.


Myocardial 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.


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© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Radiology and Imaging Sciences, Winship Cancer InsitituteEmory UniversityAtlantaUSA
  2. 2.Department of Biomedical EngineeringJohns Hopkins University School of MedicineBaltimoreUSA
  3. 3.Department of MedicineJohns Hopkins University School of MedicineBaltimoreUSA
  4. 4.Advanced Cardiovascular Imaging Laboratory, Cardiopulmonary Branch, National Heart Lung and Blood InstituteNational Institutes of HealthBethesdaUSA
  5. 5.Departments of Bioengineering, Medicine, and RadiologyUniversity of California San DiegoSan DiegoUSA

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