Technical pitfalls in image acquisition, processing and display

Förström, L; Dunn, William L.; O’Connor, Michael K.; Decklever, Teresa; Hardyman, Tim J.; Howarth, Douglas M.

doi:10.1016/s0001-2998(96)80004-3

Cited by 21 publications

(5 citation statements)

References 15 publications

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“…In the patient study, the reproducibility data in Grp2, in which the repeated scan speed was increased to twice the speed of the original scan and resulted in a 50% reduction of image count density, were observed to be significantly different from that of the control Grp1, in which the scanning speed of the repeated bone scan was maintained to obtain image counts at or above 1.5 million. The finding is concordant to the earlier studies that have shown that the proficiency of subjective assessment of bone scans varies with the total number of counts acquired (17). Higher-speed low-count images might be sufficient for a follow-up staging of a known metastatic patient who is unable to remain still for a longer time.…”

Section: Discussionsupporting

confidence: 89%

A Preanalytic Validation Study of Automated Bone Scan Index: Effect on Accuracy and Reproducibility Due to the Procedural Variabilities in Bone Scan Image Acquisition

et al. 2016

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The effect of the procedural variability in image acquisition on the quantitative assessment of bone scan is unknown. Here, we have developed and performed preanalytical studies to assess the impact of the variability in scanning speed and in vendor-specific γ-camera on reproducibility and accuracy of the automated bone scan index (BSI). Methods: Two separate preanalytical studies were performed: a patient study and a simulation study. In the patient study, to evaluate the effect on BSI reproducibility, repeated bone scans were prospectively obtained from metastatic prostate cancer patients enrolled in 3 groups (Grp). In Grp1, the repeated scan speed and the γ-camera vendor were the same as that of the original scan. In Grp2, the repeated scan was twice the speed of the original scan. In Grp3, the repeated scan used a different γ-camera vendor than that used in the original scan. In the simulation study, to evaluate the effect on BSI accuracy, bone scans of a virtual phantom with predefined skeletal tumor burden (phantom-BSI) were simulated against the range of image counts (0.2, 0.5, 1.0, and 1.5 million) and separately against the resolution settings of the γ-cameras. The automated BSI was measured with a computer-automated platform. Reproducibility was measured as the absolute difference between the repeated BSI values, and accuracy was measured as the absolute difference between the observed BSI and the phantom-BSI values. Descriptive statistics were used to compare the generated data. Results: In the patient study, 75 patients, 25 in each group, were enrolled. The reproducibility of Grp2 (mean ± SD, 0.35 ± 0.59) was observed to be significantly lower than that of Grp1 (mean ± SD, 0.10 ± 0.13; P , 0.0001) and that of Grp3 (mean ± SD, 0.09 ± 0.10; P , 0.0001). However, no significant difference was observed between the reproducibility of Grp3 and Grp1 (P 5 0.388). In the simulation study, the accuracy at 0.5 million counts (mean ± SD, 0.57 ± 0.38) and at 0.2 million counts (mean ± SD, 4.67 ± 0.85) was significantly lower than that observed at 1.5 million counts (mean ± SD, 0.20 ± 0.26; P , 0.0001). No significant difference was observed in the accuracy data of the simulation study with vendor-specific γ-cameras (P 5 0.266). Conclusion: In this study, we observed that the automated BSI accuracy and reproducibility were dependent on scanning speed but not on the vendor-specific γ-cameras. Prospective BSI studies should standardize scanning speed of bone scans to obtain image counts at or above 1.5 million. Mor e than 80% of metastatic prostate cancer patients have skeletal metastasis (1). In clinical routine, bone scan is the most common imaging modality to monitor bone metastasis. In therapeutic clinical trials, bone scan is the standard imaging modality to assess eligibility and progression for patients with metastatic prostate cancer. However, the clinical utility of bone scan is limited due to its subjective assessment, which is susceptible to the interobserver variability, and in its inability to assess re...

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Section: Discussionsupporting

confidence: 89%

A Preanalytic Validation Study of Automated Bone Scan Index: Effect on Accuracy and Reproducibility Due to the Procedural Variabilities in Bone Scan Image Acquisition

et al. 2016

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“…However, FBP can result in the generation of artifacts, which mainly consist of streaking and negative counts near the borders of hot objects. [11,13] There are myriad iterative reconstruction algorithms that can be used as alternative reconstruction techniques to FBP. However, many of these, such as maximum likelihood expectation maximization (MLEM), are computationally intensive and have never been used in clinical practice.…”

Section: Fbp Versus Osemmentioning

confidence: 99%

Optimization of ordered subset expectation maximization reconstruction for reducing urinary bladder artifacts in single-photon emission computed tomography imaging

et al. 2011

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Bladder artifact during bone single-photon emission computed tomography (SPECT) is a common source of error. The extent and severity of bladder artifacts have been described for filtered back projection (FBP) reconstruction. Ordered subset expectation maximization (OSEM) may help to address this problem of bladder artifacts, which render up to 20% of the SPECT images unreadable. The objective of this study was to evaluate the relationship of the bladder to acetabulum ratio in guiding the choice of the number of iterations and subsets used for OSEM reconstruction, for reducing bladder artifacts found on FBP reconstruction. One hundred five patients with various indications for bone scans were selected and planar and SPECT images were acquired. The SPECT images were reconstructed with both FBP and OSEM using four different combinations of iterations and subsets. The images were given to three experienced nuclear physicians who were blinded to the diagnosis and type of reconstruction used. They then labeled images from the best to the worst after which the data were analyzed. The bladder to acetabulum ratio for each image was determined which was then correlated with the different iterations and subsets used. The study demonstrated that reconstruction using OSEM led to better lesion detectability compared to FBP in 87.62% of cases. It further demonstrated that the iterations and subsets used for reconstruction of an image correlate with the bladder to acetabulum ratio. Four iterations and 8 subsets yielded the best results in 48.5% of the images, whilst 2 iterations and 8 subsets yielded the best results in 33.8%. The number of reconstructed images which yielded the best results with 2 iterations and 8 subsets was the same as or more than those with 4 iterations and 8 subsets when the bladder/acetabulum ratio (A/B) was between 0.2 and 0.39. A ratio below 0.2 or above 0.39 supports the usage of 4 iterations and 8 subsets over 2 iterations and 8 subsets. We conclude that bladder to acetabulum ratio can be used to select the optimum number of iterations and subsets for reconstruction of bone SPECT for accurate characterization of lesions. This study also confirms that reconstruction with OSEM (vs. FBP) leads to better lesion detectability and characterization.

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“…Over recent years, a series of publications have reported on limitations, artefacts and image distortions of SPECT and CT.[1819202122232425] Patient motion was identified as a major contributor to SPECT/CT misregistration. This emphasizes the importance of patient preparation-the need for patient comfort during scanning and reducing scan time to a minimum.…”

Section: Introductionmentioning

confidence: 99%

“…[13][14][15] Studies have indicated that patient motion particularly during the long SPECT or PET scanning was the major contributor to the misregistration errors in hybrid systems. [16][17][18] Over recent years, a series of publications have reported on limitations, artefacts and image distortions of SPECT and CT. [18][19][20][21][22][23][24][25] Patient motion was identified as a major contributor to SPECT/CT misregistration. This emphasizes the importance of patient preparation-the need for patient comfort during scanning and reducing scan time to a minimum.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Inter-modality Spatial Alignment Accuracy in Hybrid Single Photon Emission Computed Tomography in Patients with Hand and Wrist Pain

et al. 2013

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Single photon emission computed tomography (SPECT) and computed tomography (CT) integrated in one system (SPECT/CT) is an effective co-registration technique that helps to localize and characterize lesions in the hand and wrist. However, patient motion may cause misalignment between the two modalities leading to potential misdiagnosis. The aim of the present study was to evaluate the hardware-based registration accuracy of multislice SPECT/CT of the hand and wrist and to determine the effect of misalignment errors on diagnostic accuracy. A total of 55 patients who had multislice SPECT/CT of the hand and wrist between July 2008 and January 2010 were included. Two reviewers independently evaluated the fused images for any misalignments with six degrees of freedom: Translation and rotation in the X, Y and Z directions. The results were tested against an automated fusion tool (Syntegra). More than half of the patients had moved during SPECT scanning (Reviewer 1: 29 patients; Reviewer 2: 30 patients) and they all originated in the Y-direction translation (vertical hand motion). Five fused images had significant misalignment errors that could have led to misdiagnosis. The Wilcoxon test indicated statistically non-significant difference (P > 0.05) between reviewers and statistically non-significant difference between the reviewers and software registration. The study also showed high inter-reviewer agreement (κ = 0.87). Hand movement during the SPECT scan was common, but significant misalignments and subsequent misdiagnosis were infrequent. Future studies should investigate the use of hand and wrist immobilization devices and reductions of scan time to minimize patient motion.

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Technical pitfalls in image acquisition, processing and display

Cited by 21 publications

References 15 publications

A Preanalytic Validation Study of Automated Bone Scan Index: Effect on Accuracy and Reproducibility Due to the Procedural Variabilities in Bone Scan Image Acquisition

A Preanalytic Validation Study of Automated Bone Scan Index: Effect on Accuracy and Reproducibility Due to the Procedural Variabilities in Bone Scan Image Acquisition

Optimization of ordered subset expectation maximization reconstruction for reducing urinary bladder artifacts in single-photon emission computed tomography imaging

Assessment of Inter-modality Spatial Alignment Accuracy in Hybrid Single Photon Emission Computed Tomography in Patients with Hand and Wrist Pain

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