Influence of Reconstruction Parameters During Filtered Backprojection and Ordered-Subset Expectation Maximization in the Measurement of the Left-Ventricular Volumes and Function During Gated SPECT

Duarte, Diana D.; Monteiro, Marina S.; Hakmaoui, Fatima El; Prior, John O.; Vieira, Lina; Pires-Jorge, José A.

doi:10.2967/jnmt.111.094599

Cited by 14 publications

(11 citation statements)

References 26 publications

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“…It is well known that the cutoff frequency strategy and reconstruction parameters affect SPECT image quality. [29][30][31] Our results obtained using the ischemic insert show similar findings to several previous studies; thus, our proposed ischemic inserts can be used to evaluate image quality, optimization of cutoff frequency, and reconstruction parameters.…”

Section: Discussionsupporting

confidence: 87%

Technical Note: Development of an ischemic defect model insert attachable to a commercially available myocardial phantom

et al. 2020

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Objective: The purpose of this study was to develop a novel myocardial phantom insert model that attaches to commercially available myocardial phantoms and simulates an ischemic area, using threedimensional printing technology. Methods: Ischemic inserts were designed to give four levels of absolute percent contrast (Low; 10%, Medium; 20%, High; 35%, and Defect; 100%) using CT images and computer-aided design software. The ischemic insert was composed of multiple slit structures to replicate myocardial ischemia. Myocardial phantom images with developed ischemic inserts were acquired using a SPECT/CT system and were then reconstructed using filtered back projection (FBP) and iterative reconstruction (IR) with various cutoff frequencies of a Butterworth filter. The performance and utility of ischemic inserts were evaluated according to percent contrast and 5-point scoring. Results: The percent contrast and scoring results changed according to the ischemic insert type, cutoff frequency, and reconstruction method. The percent contrast of each insert obtained by FBP with 0.4 cycles/cm was 4.1% (Low), 15.7% (Medium), 17.4% (High), and 36.1% (Defect). Similarly, the percent contrast of each insert obtained by IR with 0.4 cycles/cm was 5.0% (Low), 17.0% (Medium), 21.9% (High), and 47.7% (Defect). Conclusions: We successfully developed an ischemic insert that attaches to a commercially available myocardial phantom by using CT imaging and 3D printing technology. Our proposed ischemic insert provided several abnormal perfusion patterns on myocardial SPECT images and may be useful for evaluating SPECT image quality.

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Section: Discussionsupporting

confidence: 87%

Technical Note: Development of an ischemic defect model insert attachable to a commercially available myocardial phantom

et al. 2020

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“…There exist many digital filters; however, use of a single filter with selected parameters on the data of different types of clinical studies is impractical. In general, selection of digital filters and their appropriate parameters for the use on the clinical SPECT data is based on the operator's observations and experience instead of theoretical or logical scientific justification [4,24]. However, the choice of a filter and its functions for a particular image processing assignment is a balancing act between noise removal, enhancement of image details, and contrast [25].…”

Section: Discussionmentioning

confidence: 99%

Comparison of Low-Pass Filters for SPECT Imaging

Sayed

Ismail

2020

International Journal of Biomedical Imaging

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In single photon emission computed tomography (SPECT) imaging, the choice of a suitable filter and its parameters for noise reduction purposes is a big challenge. Adverse effects on image quality arise if an improper filter is selected. Filtered back projection (FBP) is the most popular technique for image reconstruction in SPECT. With this technique, different types of reconstruction filters are used, such as the Butterworth and the Hamming. In this study, the effects on the quality of reconstructed images of the Butterworth filter were compared with the ones of the Hamming filter. A Philips ADAC forte gamma camera was used. A low-energy, high-resolution collimator was installed on the gamma camera. SPECT data were acquired by scanning a phantom with an insert composed of hot and cold regions. A Technetium-99m radioactive solution was homogenously mixed into the phantom. Furthermore, a symmetrical energy window (20%) centered at 140 keV was adjusted. Images were reconstructed by the FBP method. Various cutoff frequency values, namely, 0.35, 0.40, 0.45, and 0.50 cycles/cm, were selected for both filters, whereas for the Butterworth filter, the order was set at 7. Images of hot and cold regions were analyzed in terms of detectability, contrast, and signal-to-noise ratio (SNR). The findings of our study indicate that the Butterworth filter was able to expose more hot and cold regions in reconstructed images. In addition, higher contrast values were recorded, as compared to the Hamming filter. However, with the Butterworth filter, the decrease in SNR for both types of regions with the increase in cutoff frequency as compared to the Hamming filter was obtained. Overall, the Butterworth filter under investigation provided superior results than the Hamming filter. Effects of both filters on the quality of hot and cold region images varied with the change in cutoff frequency.

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“…The filter has been studied in terms of varying cut-off frequency values while keeping the order constant, considering the cut-off frequency is very important and the influence of the order chosen for the image quality is less significant [6]- [8] [12]. The reason to the Butterworth filter frequency (0.35 cycles•cm −1 ) was chosen for this research was that it is widely used for almost all clinical SPECT studies with order 5 in the department where the study was conducted.…”

Section: Introductionmentioning

confidence: 99%

Effect of Cut-Off Frequency of Butterworth Filter on Detectability and Contrast of Hot and Cold Regions in Tc-99m SPECT

Sayed¹,

Nasrudin²

2016

IJMPCERO

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In SPECT, noise is one of the major limitations that degrade image quality. To suppress the noisy signals in an image, digital filters are most commonly applied. However, in SPECT image reconstruction, selection of an appropriate filter and its functions has always remained a difficult task. In this work an attempt was made to investigate the effects of varying cut-off frequencies and in keeping the order of Butterworth filter constant on detectability and contrast of hot and cold regions images. A new insert simulating hot and cold regions which provides similar views in a reconstructed image was placed in the phantom's cylindrical source tank and imaged. Tc-99m radionuclide was distributed uniformly in the phantom. SPECT data were collected in a 20% energy window centered at 140 keV by a Philips ADAC Forte dual head gamma camera mounted with a LEHR collimator. Images were generated by using the filtered backprojection technique. A Butterworth filter of order 5 with cut-off frequencies 0.35 and 0.45 cycles•cm −1 was applied. Images were examined in terms of hot and cold regions, detectability and contrast. Results show that the hot and cold regions' detectability and contrast vary with the change of cut-off frequency. With a 0.45 cycles•cm −1 cut-off frequency, a significant enhancement in contrast of cold regions was achieved as compared to a 0.35 cycles•cm −1 cut-off frequency. Furthermore, the detectability of hot and cold regions improved with the use of a 0.45 cycles•cm −1 cut-off frequency. In conclusion, image quality of hot and cold regions affected in a different way with a change of cut-off frequency. Thus, care should be taken in selecting the filter cut-off frequency prior to reconstruction of images; particularly, when both types of regions are expected in the reconstructed image.

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Influence of Reconstruction Parameters During Filtered Backprojection and Ordered-Subset Expectation Maximization in the Measurement of the Left-Ventricular Volumes and Function During Gated SPECT

Cited by 14 publications

References 26 publications

Technical Note: Development of an ischemic defect model insert attachable to a commercially available myocardial phantom

Technical Note: Development of an ischemic defect model insert attachable to a commercially available myocardial phantom

Comparison of Low-Pass Filters for SPECT Imaging

Effect of Cut-Off Frequency of Butterworth Filter on Detectability and Contrast of Hot and Cold Regions in Tc-99m SPECT

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