A multi-center phantom study comparing image resolution from three state-of-the-art SPECT-CT systems

Hughes, Tyler; Shcherbinin, Sergey; Celler, Anna

doi:10.1007/s12350-009-9132-7

Cited by 17 publications

(9 citation statements)

References 22 publications

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“…The present study was performed to assess the feasibility of an OSEM reconstruction algorithm and CT-based attenuation correction (Flash 3D), which has been reported to improve image quality and quantitation performance by applying compensation techniques for photon attenuation, Compton scatter and 3-dimensional depthdependent resolution [12,13,15]. First, we compared the impact of Flash 3D versus FBP on myocardial perfusion defect and severity quantification in 20 patients who had undergone both stress-rest myocardial perfusion SPECT and coronary angiography.…”

Section: Discussionmentioning

confidence: 99%

Quantitative Comparison of Myocardial Perfusion Defects using Different Reconstruction Algorithms

Naum¹,

Kleven-Madsen²

2012

J Clinic Experiment Cardiol

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Objective: To investigate the impact of a reconstruction method incorporating corrections for scatter, attenuation, and distance dependent detector response on cardiac single emission computed tomography (SPECT) perfusion studies compared with filtered back projection (FBP). Materials and methods: A total of 20 patients underwent same-day, rest-stress SPECT/CT myocardial perfusion imaging. Images were reconstructed using iterative 3D ordered-subsets expectation-maximization (OSEM 3D) and FBP algorithms. Stress and rest myocardial perfusion defects were quantified using polar maps and normal database comparisons. The Bland-Altman plots were used to assess their degree of agreement. Results were confirmed by coronary angiography. The contrast, contrast to noise ratio and signal to noise ratio were used for the quantitative evaluation of the reconstruction quality. Results: Perfusion defect extent quantification on OSEM 3D reconstructed images agreed and correlated well with defect extent quantification on FBP reconstructed images (bias ± standard deviation,-15% ± 20; r = 0.63) during stress and at rest (-10% ±15; r=0.70). Agreement and correlation were similar for severity scores during stress (-1.02 ± 1.77 SD's; r=0.62), and at rest (-1.10 ± 1.49 SD's; r=0.61). There were no statistically significant differences between the methods regarding perfusion defect extent or severity. The overall agreement rate with coronary angiography was similar. OSEM 3D reconstruction algorithm significantly increases the image contrast by 31% (P<0.05). Conclusions: Compensation for detector response, attenuation and scatter improves image contrast compared with FBP. Applying quantitative analysis, OSEM 3D reconstruction produced increased image contrast compared to FBP, but similar results regarding the size and severity of left ventricular perfusion defects.

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Section: Discussionmentioning

confidence: 99%

Quantitative Comparison of Myocardial Perfusion Defects using Different Reconstruction Algorithms

Naum¹,

Kleven-Madsen²

2012

J Clinic Experiment Cardiol

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“…They showed that these systems performed differently in terms of quantitative accuracy, contrast, signal-to-noise, and uniformity. In a different study [34] in which they compared the same three SPECT/ CT systems, they showed that image resolution is very much dependent on the reconstruction algorithm. In recent years, various SPECT/CT and software vendors have responded to the increasing need for SPECT quantification and now commercially offer software packages for quantification of several radionuclides including 99m Tc, 111 In, 131 I, and 177 Lu [35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Towards standardization of absolute SPECT/CT quantification: a multi-center and multi-vendor phantom study

et al. 2019

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Absolute quantification of radiotracer distribution using SPECT/CT imaging is of great importance for dosimetry aimed at personalized radionuclide precision treatment. However, its accuracy depends on many factors. Using phantom measurements, this multi-vendor and multi-center study evaluates the quantitative accuracy and inter-system variability of various SPECT/CT systems as well as the effect of patient size, processing software and reconstruction algorithms on recovery coefficients (RC). Methods: Five SPECT/CT systems were included: Discovery™ NM/CT 670 Pro (GE Healthcare), Precedence™ 6 (Philips Healthcare), Symbia Intevo™, and Symbia™ T16 (twice) (Siemens Healthineers). Three phantoms were used based on the NEMA IEC body phantom without lung insert simulating body mass indexes (BMI) of 25, 28, and 47 kg/m 2. Six spheres (0.5-26.5 mL) and background were filled with 0.1 and 0.01 MBq/mL 99m Tc-pertechnetate, respectively. Volumes of interest (VOI) of spheres were obtained by a region growing technique using a 50% threshold of the maximum voxel value corrected for background activity. RC, defined as imaged activity concentration divided by actual activity concentration, were determined for maximum (RC max) and mean voxel value (RC mean) in the VOI for each sphere diameter. Inter-system variability was expressed as median absolute deviation (MAD) of RC. Acquisition settings were standardized. Images were reconstructed using vendor-specific 3D iterative reconstruction algorithms with institute-specific settings used in clinical practice and processed using a standardized, in-house developed processing tool based on the SimpleITK framework. Additionally, all data were reconstructed with a vendor-neutral reconstruction algorithm (Hybrid Recon™; Hermes Medical Solutions). Results: RC decreased with decreasing sphere diameter for each system. Intersystem variability (MAD) was 16 and 17% for RC mean and RC max , respectively. Standardized reconstruction decreased this variability to 4 and 5%. High BMI hampers quantification of small lesions (< 10 ml). Conclusion: Absolute SPECT quantification in a multi-center and multi-vendor setting is feasible, especially when reconstruction protocols are standardized, paving the way for a standard for absolute quantitative SPECT.

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“…Some of the more pertinent publications include a simulation study of the convergence of object dependent resolution in maximum likelihood algorithms, (5) the estimation of the recovery coefficient based on hot spheres using OSEM, (6) and a comparison of resolution between different SPECT/CT systems using machine-specific reconstruction algorithms. (7) However, the detailed characterization of SPECT system resolution under varying imaging and OSEM reconstruction conditions across the field of view has not been performed. The objectives of this work are to characterize the behavior of the radial and tangential resolution of a SPECT/CT system under scatter and attenuation using OSEM iterative reconstruction as a function of: (i) location within the scan field of view; (ii) SPECT voxel size; and (iii) number of iterations and subsets.…”

Section: Introductionmentioning

confidence: 99%

Effects of voxel size and iterative reconstruction parameters on the spatial resolution of SPECT/CT

Kappadath

2011

J Applied Clin Med Phys

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The purpose of this study was to evaluate the effects of voxel size and iterative reconstruction parameters on the radial and tangential resolution for 99mTc SPECT as a function of radial distance from isocenter. SPECT/CT scans of eight coplanar point sources of size smaller than 1 mm3 containing high concentration 99mTc solution were acquired on a SPECT/CT system with 5/8 inch NaI(Tl) detector and low-energy, high-resolution collimator. The tomographic projection images were acquired in step-and-shoot mode for 360 views over 360° with 250,000 counts per view, a zoom of 2.67, and an image matrix of 256 × 256 pixels that resulted in a 0.9 × 0.9 × 0.9 mm3 SPECT voxel size over 230 mm field-of-view. The projection images were also rebinned to image matrices of 128 × 128 and 64 × 64 to yield SPECT voxel sizes of 1.8 × 1.8 × 1.8 and 3.6 × 3.6 × 3.6 mm3, respectively. The SPECT/CT datasets were reconstructed using the vendor-supplied iterative reconstruction software that incorporated collimator-specific resolution recovery, CT-based attenuation correction, and dual-energy window-based scatter correction using different combinations of iterations and subsets. SPECT spatial resolution was estimated as the full width at half maximum of the radial and tangential profiles through the center of each point source in reconstructed SPECT images. Both radial and tangential resolution improved with higher iterations and subsets, and with smaller voxel sizes. Both radial and tangential resolution also improved with radial distance further away from isocenter. The magnitude of variation decreased for smaller voxel sizes and for higher number of iterations and subsets. Tangential resolution was found not to be equal to the radial resolution, and the nature of the anisotropy depended on the distribution of the radionuclide and on the reconstruction parameters used. The tangential resolution converged faster than the radial resolution, with higher iterations and subsets. SPECT resolution was isotropic and independent of radial distance when reconstructed using filtered back-projection. SPECT spatial resolution and therefore quantification of SPECT uptake via partial-volume correction in clinical images were found to depend on the nature of activity distribution within the SPECT field-of-view and on the specific choice of iterative reconstruction parameters.

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A multi-center phantom study comparing image resolution from three state-of-the-art SPECT-CT systems

Cited by 17 publications

References 22 publications

Quantitative Comparison of Myocardial Perfusion Defects using Different Reconstruction Algorithms

Quantitative Comparison of Myocardial Perfusion Defects using Different Reconstruction Algorithms

Towards standardization of absolute SPECT/CT quantification: a multi-center and multi-vendor phantom study

Effects of voxel size and iterative reconstruction parameters on the spatial resolution of SPECT/CT

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