Impact of injection dose, post-reconstruction filtering, and collimator choice on image quality of myocardial perfusion SPECT using cadmium-zinc telluride detectors in the rat

Mizutani, Asuka; Matsunari, Ichiro; Kobayashi, Masato; Nishi, Kodai; Fujita, Wataru; Miyazaki, Yoshiharu; Nekolla, Stephan G.; Kawai, Keiichi

doi:10.1186/s40658-015-0111-6

Cited by 5 publications

(4 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A SPECT system with cadmium-zinc telluride detectors and two different five-pinhole collimators was used (sensitivity = 321 cps/MBq, 139 cps/MBq; resolution = 1.5 mm, 1.2 mm). The evaluation by two readers showed an increase in image quality by higher injection dose (25–200 MBq) and stronger filters (no filter; FWHM = 1.5 mm, 2.5 mm) 14 . The injection dose had more impact on the image quality score than we found for the scan time, but the results are still largely consistent with ours.…”

Section: Discussionmentioning

confidence: 97%

“…High spatial resolution can improve the diagnostic value of SPECT scans if sufficient image quality is achieved, which is particularly affected by the choice of collimator 12 , reconstruction algorithm 5 , 13 , post-reconstruction filter 13 and injection dose 14 . Hence, we evaluated the influence of acquisition time and Gaussian post-filtering, using a novel iterative reconstruction algorithm with similarity-regulated ordered-subsets expectation maximization (SROSEM), that enables constant reconstruction parameters for a wide range of activity concentrations 15 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Capabilities of multi-pinhole SPECT with two stationary detectors for in vivo rat imaging

Janssen

Hoffmann

Kitasaka

et al. 2020

Sci Rep

View full text Add to dashboard Cite

We aimed to investigate the image quality of the U-SPECT5/CT E-Class a micro single-photon emission computed tomography (SPECT) system with two large stationary detectors for visualization of rat hearts and bones using clinically available 99mTc-labelled tracers. Sensitivity, spatial resolution, uniformity and contrast-to-noise ratio (CNR) of the small-animal SPECT scanner were investigated in phantom studies using an ultra-high-resolution rat and mouse multi-pinhole collimator (UHR-RM). Point source, hot-rod, and uniform phantoms with 99mTc-solution were scanned for high-count performance assessment and count levels equal to animal scans, respectively. Reconstruction was performed using the similarity-regulated ordered-subsets expectation maximization (SROSEM) algorithm with Gaussian smoothing. Rats were injected with ~ 100 MBq [99mTc]Tc-MIBI or ~ 150 MBq [99mTc]Tc-HMDP and received multi-frame micro-SPECT imaging after tracer distribution. Animal scans were reconstructed for three different acquisition times and post-processed with different sized Gaussian filters. Following reconstruction, CNR was calculated and image quality evaluated by three independent readers on a five-point scale from 1 = “very poor” to 5 = “very good”. Point source sensitivity was 567 cps/MBq and radioactive rods as small as 1.2 mm were resolved with the UHR-RM collimator. Collimator-dependent uniformity was 55.5%. Phantom CNR improved with increasing rod size, filter size and activity concentration. Left ventricle and bone structures were successfully visualized in rat experiments. Image quality was strongly affected by the extent of post-filtering, whereas scan time did not have substantial influence on visual assessment. Good image quality was achieved for resolution range greater than 1.8 mm in bone and 2.8 mm in heart. The recently introduced small animal SPECT system with two stationary detectors and UHR-RM collimator is capable to provide excellent image quality in heart and bone scans in a rat using standardized reconstruction parameters and appropriate post-filtering. However, there are still challenges in achieving maximum system resolution in the sub-millimeter range with in vivo settings under limited injection dose and acquisition time.

show abstract

Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Capabilities of multi-pinhole SPECT with two stationary detectors for in vivo rat imaging

Janssen

Hoffmann

Kitasaka

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Interestingly, these authors reported an unexpected relatively low perfusion in the distal segments of the lateral wall (10). There is no mention to such feature in a later study on the optimization of injected activity and reconstruction parameters in male Wistar rats imaged with 99m Tc-tetrofosmin using cadmium–zinc telluride detectors (25). …”

Section: Measurement Of Cardiac Perfusionmentioning

confidence: 99%

Cardiac Radionuclide Imaging in Rodents: A Review of Methods, Results, and Factors at Play

et al. 2017

View full text Add to dashboard Cite

The interest around small-animal cardiac radionuclide imaging is growing as rodent models can be manipulated to allow the simulation of human diseases. In addition to new radiopharmaceuticals testing, often researchers apply well-established probes to animal models, to follow the evolution of the target disease. This reverse translation of standard radiopharmaceuticals to rodent models is complicated by technical shortcomings and by obvious differences between human and rodent cardiac physiology. In addition, radionuclide studies involving small animals are affected by several extrinsic variables, such as the choice of anesthetic. In this paper, we review the major cardiac features that can be studied with classical single-photon and positron-emitting radiopharmaceuticals, namely, cardiac function, perfusion and metabolism, as well as the results and pitfalls of small-animal radionuclide imaging techniques. In addition, we provide a concise guide to the understanding of the most frequently used anesthetics such as ketamine/xylazine, isoflurane, and pentobarbital. We address in particular their mechanisms of action and the potential effects on radionuclide imaging. Indeed, cardiac function, perfusion, and metabolism can all be significantly affected by varying anesthetics and animal handling conditions.

show abstract

“…Therefore there is no accordance between authors concerning the best Fc for Butterworth filter in SPECT imaging [6,7]. It is suggested that the Fc should be determined by referring to the total counts in each examination [8,9]. For high count images, a higher Fc is preferred to optimize the reconstruction process of an image.…”

Section: Introductionmentioning

confidence: 99%

Optimizing Breast Cancer Images from Wire Mesh Collimator SPECT Camera Using Characterized Butterworth Filter

Mi¹

2018

IJNMRS

View full text Add to dashboard Cite

Background: Previous studies have shown that SPECT camera coupled with Wire Mesh Collimator (WMC) has good sensitivity in detecting breast cancer. In this paper, we intend to improve the breast cancer detection through enhancing images by characterized Butterworth filter. The characterization was based on trade-off between noise suppression and spatial resolution degradation. Methods: Monte Carlo simulation studies were performed to obtain projections for a half-ellipsoidal breast phantom in the prone position with five different tumor sizes, and four projection sets with acquisitions of 20, 40, 80, 160 seconds were simulated which gave different count density in the range of 28 to 229 counts/cm 2 for each tumor size. Butterworth filter was used to filter the sinograms with 13 different cutoff frequency (Fc), ranging from 0.2 to 0.8 Nyquist frequency (Nq) with 0.05 steps. The relationship between optimum Fc, count density and tumor size were revealed. Results:The results showed that the optimum Fc not only depended on count density but also linked to the change of tumor size. For the case of tumor size, it is suggested that the Fc can be relocated to a higher spatial frequency when tumor size was close to the spatial resolution of SPECT system in order to preserve tumor signal. Conclusion:It may be possible to use a priori knowledge of tumor size and count density as guideline for choosing the optimal parameters of Butterworth filter in Tc-99m breast SPECT imaging.

show abstract

Impact of injection dose, post-reconstruction filtering, and collimator choice on image quality of myocardial perfusion SPECT using cadmium-zinc telluride detectors in the rat

Cited by 5 publications

References 23 publications

Capabilities of multi-pinhole SPECT with two stationary detectors for in vivo rat imaging

Capabilities of multi-pinhole SPECT with two stationary detectors for in vivo rat imaging

Cardiac Radionuclide Imaging in Rodents: A Review of Methods, Results, and Factors at Play

Optimizing Breast Cancer Images from Wire Mesh Collimator SPECT Camera Using Characterized Butterworth Filter

Contact Info

Product

Resources

About