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

Sayed, Inayatullah Shah; Nasrudin, Nor Syahirah Mohamed

doi:10.4236/ijmpcero.2016.51011

Cited by 5 publications

(4 citation statements)

References 10 publications

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“…Specimen areas were selected, and individual images were saved in a 24-bit RGB TIFF file format with a resolution of 1 μm/pixel using the ZEISS Microscopy Software. The slides with periostin staining were used for quantitative analysis using ImageJ ( https://imagej.net/ij/ ) 59 . The images were converted 8-bit.…”

Section: Methodsmentioning

confidence: 99%

“…Specimen areas were selected, and individual images were saved in a 24-bit RGB TIFF file format with a resolution of 1 μm/pixel using the ZEISS Microscopy Software. The width of the gap between the opposing edges was measured at four arbitrary points at each time point using ImageJ software ( https://imagej.net/ij/ ) 59 . The means across all four measurements were calculated, normalized to the time 0-h, and compared between the CM CTL and CM POSTNhigh using two-way ANOVA.…”

Section: Methodsmentioning

confidence: 99%

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Periostin facilitates ovarian cancer recurrence by enhancing cancer stemness

Huang,

Byrd,

Tan

et al. 2023

Sci Rep

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The lethality of epithelial ovarian cancer (OC) is largely due to a high rate of recurrence and development of chemoresistance, which requires synergy between cancer cells and the tumor microenvironment (TME) and is thought to involve cancer stem cells. Our analysis of gene expression microarray data from paired primary and recurrent OC tissues revealed significantly elevated expression of the gene encoding periostin (POSTN) in recurrent OC compared to matched primary tumors (p = 0.015). Secreted POSTN plays a role in the extracellular matrix, facilitating epithelial cell migration and tissue regeneration. We therefore examined how elevated extracellular POSTN, as we found is present in recurrent OC, impacts OC cell functions and phenotypes, including stemness. OC cells cultured with conditioned media with high levels of periostin (CMPOSTNhigh) exhibited faster migration (p = 0.0044), enhanced invasiveness (p = 0.006), increased chemoresistance (p < 0.05), and decreased apoptosis as compared to the same cells cultured with control medium (CMCTL). Further, CMPOSTNhigh-cultured OC cells exhibited an elevated stem cell side population (p = 0.027) along with increased expression of cancer stem cell marker CD133 relative to CMCTL-cultured cells. POSTN-transfected 3T3-L1 cells that were used to generate CMPOSTNhigh had visibly enhanced intracellular and extracellular lipids, which was also linked to increased OC cell expression of fatty acid synthetase (FASN) that functions as a central regulator of lipid metabolism and plays a critical role in the growth and survival of tumors. Additionally, POSTN functions in the TME were linked to AKT pathway activities. The mean tumor volume in mice injected with CMPOSTNhigh-cultured OC cells was larger than that in mice injected with CMCTL-cultured OC cells (p = 0.0023). Taken together, these results show that elevated POSTN in the extracellular environment leads to more aggressive OC cell behavior and an increase in cancer stemness, suggesting that increased levels of stromal POSTN during OC recurrence contribute to more rapid disease progression and may be a novel therapeutic target. Furthermore, they also demonstrate the utility of having matched primary-recurrent OC tissues for analysis and support the need for better understanding of the molecular changes that occur with OC recurrence to develop ways to undermine those processes.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Periostin facilitates ovarian cancer recurrence by enhancing cancer stemness

Huang,

Byrd,

Tan

et al. 2023

Sci Rep

View full text Add to dashboard Cite

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“…Furthermore, it also indicated that the impact on image quality varies with respect to the size of hot regions as well as the count density in the region of interest which is the case in this study. Moreover, higher frequency corresponds to small regions and to abrupt changes in the count density of regions of interest [26][27][28][29].…”

Section: International Journal Of Biomedical Imagingmentioning

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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“…Noise removal of raw SPECT projection data has been typically conducted by a low-pass filter to eliminate high-frequency noise which causes artifacts of SPECT reconstruction [2] [3] [4] [5] [6]. A Butterworth filter, which is usually used as a low-pass filter, however, cannot distinguish signal from noise.…”

Section: Introductionmentioning

confidence: 99%

Denoising Projection Data with a Robust Adaptive Bilateral Filter in Low-Count SPECT

Nakabayashi¹,

Chikamatsu²,

Okamoto³

et al. 2018

IJMPCERO

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Low-count SPECT images are well known to be smoothed strongly by a Butterworth filter for statistical noise reduction. Reconstructed images have a low signal-to-noise ratio (SNR) and spatial resolution because of the removal of high-frequency signal components. Using the developed robust adaptive bilateral filter (RABF), which was designed as a pre-stage filter of the Butterworth filter, this study was conducted to improve SNR without degrading the spatial resolution for low-count SPECT imaging. The filter can remove noise while preserving spatial resolution. To evaluate the proposed method, we extracted SNR and spatial resolution in a phantom study. We also conducted paired comparison for visual image quality evaluation in a clinical study. Results show that SNR was increased 1.4 times without degrading the spatial resolution. Visual image quality was improved significantly (p < 0.01) for clinical low-count data. Moreover, the accumulation structure became sharper. A structure embedded in noise emerged. Our method, which denoises without degrading the spatial resolution for low-count SPECT images, is expected to increase the effectiveness of diagnosis for low-dose scanning and short acquisition time scanning.

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

Cited by 5 publications

References 10 publications

Periostin facilitates ovarian cancer recurrence by enhancing cancer stemness

Periostin facilitates ovarian cancer recurrence by enhancing cancer stemness

Comparison of Low-Pass Filters for SPECT Imaging

Denoising Projection Data with a Robust Adaptive Bilateral Filter in Low-Count SPECT

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