Noise reduction and motion elimination in low-dose 4D myocardial computed tomography perfusion (CTP): preliminary clinical evaluation of the ASTRA4D algorithm

Eur Radiol. 2019 Sep;29(9):4572-4582. doi: 10.1007/s00330-018-5899-8. Epub 2019 Feb 4.


Objectives: To propose and evaluate a four-dimensional (4D) algorithm for joint motion elimination and spatiotemporal noise reduction in low-dose dynamic myocardial computed tomography perfusion (CTP).

Methods: Thirty patients with suspected or confirmed coronary artery disease were prospectively included and underwent dynamic contrast-enhanced 320-row CTP. A novel deformable image registration method based on the principal component analysis (PCA) of the ante hoc temporally smoothed voxel-wise time-attenuation curves (ASTRA4D) is presented. Quantitative (standard deviation, signal-to-noise ratio (SNR), temporal variation, volumetric deformation) and qualitative (motion, contrast, contour sharpness [1, poor; 5, excellent]) measures of CTP quality were assessed for the original and motion-compensated sequences (without and with temporal filtering, PCA/ASTRA4D). Following myocardial perfusion deficit detection by two readers, diagnostic accuracy was evaluated using magnetic resonance myocardial perfusion imaging (MR-MPI) as the reference standard in 15 patients.

Results: Registration using ASTRA4D was successful in all 30 patients and resulted in comparison with the benchmark PCA in significantly (p < 0.001) reduced noise over time (- 83%, 178.5 vs 29.9) and spatially (- 34%, 21.4 vs 14.1) as well as improved SNR (+ 47%, 3.6 vs 5.3) and subjective image quality (motion, contrast, contour sharpness [+ 1.0, + 1.0, + 0.5]). ASTRA4D had significantly improved per-segment sensitivity of 91% (58/64) and similar specificity of 96% (429/446) compared with PCA (52%, 33/64; 98%, 435/446; p = 0.011) in the visual detection of perfusion deficits.

Conclusions: The ASTRA4D registration algorithm improved the spatiotemporal noise profile and CTP sequence image quality, resulting in significantly improved sensitivity of 4D CTP in the detection of myocardial ischemia.

Key points: • ASTRA4D combines local temporal regression and deformable image registration. • Quantitative and qualitative measures of CTP quality are improved compared to PCA. • Improved spatiotemporal differentiation of ischemic regions leads to an excellent perfusion deficit concordance of ASTRA4D with MRI.

Keywords: Computed tomography myocardial perfusion imaging; Coronary artery disease; Deformable registration; Motion artifacts; Temporal averaging.

Publication types

  • Evaluation Study

MeSH terms

  • Aged
  • Algorithms
  • Artifacts
  • Coronary Artery Disease / diagnostic imaging*
  • Coronary Artery Disease / physiopathology
  • Female
  • Four-Dimensional Computed Tomography / methods*
  • Humans
  • Magnetic Resonance Imaging / methods
  • Male
  • Middle Aged
  • Motion
  • Myocardial Ischemia / diagnostic imaging
  • Myocardial Perfusion Imaging / methods
  • Perfusion
  • Radiographic Image Interpretation, Computer-Assisted / methods
  • Sensitivity and Specificity
  • Signal-To-Noise Ratio