Related Experiment Video
Updated: Apr 18, 2026
Retrospective Cardiac Gating with A Prototype Small-Animal X-ray Computed Tomograph
Published on: February 21, 2025
Effects of filtration on right ventricular function by the gated blood pool SPECT
Samane Mohseni1, Alireza Kamali-Asl, Ahmad Bitarafan-Rajabi
1Radiation Medicine Engineering Department, Shahid Beheshti University, GC, Velenjak, Tehran, Iran.
Insights
Different filters significantly impact right ventricular volume calculations in gated blood pool SPECT. Butterworth and resolution recovery filters offer the most accurate results for ventricular volumes compared to the NCAT phantom.
Area of Science:
- Nuclear Medicine
- Medical Imaging
- Cardiovascular Imaging
Background:
- Gated blood pool SPECT (GBPS) allows simultaneous evaluation of left and right ventricular function.
- Accurate calculation of ventricular volumes depends on the spatial resolution of reconstructed images.
Purpose of the Study:
- To evaluate the effect of different post-processing filters on right ventricular function parameters derived from GBPS.
- To determine the optimal filter for accurate right ventricular volume and ejection fraction estimation.
Main Methods:
- Utilized a 4D NURBS-based cardiac-torso (NCAT) phantom with known right ventricular (RV) volumes and ejection fraction (EF).
- Simulated projections using the SIMIND Monte Carlo program.
- Reconstructed images using Filtered Back Projection (FBP) and various post-processing filters (Butterworth, Hanning, Shepp-Logan, Metz, Wiener).
- Computed RV functional parameters using the Cedars-Sinai QBS package and compared them to NCAT phantom data.
Main Results:
- Butterworth filtration (cutoff 0.3) showed high agreement for RV end-diastolic volume (RVEDV) (1.2% RDP).
- Metz filter (FWHM 20 pixels) yielded the highest accuracy for RV ejection fraction (EF) (3% RDP).
- Butterworth filter (cutoff 0.4-0.5) provided stable RVEDV estimates (7.5% RDP), while Hanning and Shepp-Logan filters showed larger discrepancies.
Conclusions:
- Filter selection critically affects right ventricular volume computation in GBPS.
- Resolution recovery and Butterworth filters provide results comparable to actual NCAT phantom values.
- Further clinical validation is needed to establish optimal protocols.
Objective:
Gated blood po ol single photon emission computed tomography (GBPS) offers the possibility of obtaining additional functional information from blood pool studies, including evaluation of left and right ventricular function simultaneously. The calculation of ventricular volumes based on the identification of the endocardial surface would be influenced by the spatial resolution in the reconstructed images. This study was performed to evaluate the effect of different filters on the right ventricular function.
Methods:
The normal four-dimensional (4-D) NURBS-based cardiac-torso (NCAT) phantom with known right ventricular volume and ejection fraction was generated. The SIMIND Monte Carlo program was used to create projections. The studies were reconstructed by FBP and post-processing filtration such as Butterworth, Hanning, Shepp-Logan, Metz and Wiener in different statuses (cutoff and order). Using the Cedars-Sinai QBS (quantitative blood pool SPECT) package, the ventricular functional parameters were computed. The calculated values were analyzed and compared with the normal NCAT results.
Results:
The results implied that the calculated right ventricular end diastolic volume (RVEDV) by Butterworth filtration (cutoff frequency = 0.3) agreed more with the NCAT Phantom characteristics [relative difference percentage (RDP) = 1.2 %], while the maximum accordance in the calculation of the RV ejection fraction (EF) (RDP = 3 %) was observed by Metz filter (FWHM 20 pixel). Also, the results of this study demonstrate that the Butterworth filter provided the most stable values (cutoff frequency = 0.4-0.5) in the estimation of RVEDV (RDP = 7.5 %). The Hanning and Shepp-Logan filters produced a much larger RDP, particularly in low frequency (41.1 and 21.5 %, respectively) compared to other filters.
Conclusions:
This study demonstrated that the operation of different filters has a severe effect in computing right ventricular volume. The resolution recovery and Butterworth filters tend to give more comparable ventricular volumes with the actual normal NCAT value. Further evaluation using a large clinical database is underway to evaluate the optimum protocol in a clinical setting.
