Tehran University of Medical Sciences
Frontiers in Biomedical Technologies
2345-5837
1
2
2014
06
30
Evaluation Strategies for Metal Artifact Reduction Approaches in CT: a Literature Survey
82
90
EN
Mehrsima
Abdoli
Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
2015
10
13
2015
10
13
Metal-induced artifacts are known to degrade CT image quality and deteriorate the quantitative value of the images. Therefore, numerous metal artifact reduction techniques have been proposed and their performances have been evaluated using different qualitative or quantitative approaches. Various approaches and measures have been applied for the validation process visual assessment of the corrected images being one of the most commonly applied techniques. A high proportion of the presented techniques are not properly validated in the clinical environment, which hampers an unbiased comparison of the techniques and as such the clinical acceptability of the techniques remains questionable. Accurate quantitative evaluation of the processed images guarantees the reliability of the correction method. The main motivation of this work was to present the qualitative and quantitative validation approaches and metrics used in various metal artifact reduction studies in both phantom and clinical experiments. Considering the challenging task of validation of the clinical studies, where the gold standard is not present, having a proper knowledge about the potential solutions would assist the researchers to apply the right validation approaches.
https://fbt.tums.ac.ir/index.php/fbt/article/view/25
https://fbt.tums.ac.ir/index.php/fbt/article/download/25/24
amp; Radiological Science, Johns Hopkins University, School of Medicine, Baltimore, USA AND Departments of Electrical & Computer Engineering, Johns Hopkins University, School of Medicine, Baltimore, USA.
2015
10
13
2015
10
13
Purpose: Clinical myocardial perfusion SPECT is commonly performed using static imaging. Dynamic SPECT enables extraction of quantitative as well as relative perfusion information. We aimed to evaluate the ability of dynamic SPECT for regular perfusion assessment in comparison to conventional SPECT in the context of thallium-201.
Methods: Simulations were performed utilizing a 4D-NCAT phantom for a dual-head gamma camera via the SIMIND Monte-Carlo simulator. 64s acquisition time-frames were used to track these dynamic changes. Different summations of time-frames were performed to create each dataset, which were compared to a standard static dataset. In addition, the effect of different delay-times post-injection was assessed. Twenty-segment analysis of perfusion was performed via the QPS analyser. Dynamic data were subsequently acquired in clinical studies using simulation-optimized protocols.
Results: For different summations of time-frames, perfusion scores in the basal and mid regions revealed 14.4% and 7.3% increases in dynamic SPECT compared to conventional imaging, with maximum changes in the basal anterior, while the distal and apical segments did not show noticeable changes. Specifically, dynamic imaging including 4 to 6 time-frames yielded enhanced correlation (R=0.957) with conventional imaging, in comparision to the usage of less time frames. Greatest correlation with conventional imaging was obtained for post-injection delays of 320 to 448s (R=0.982 to R=0.988).
Conclusion: While dynamic SPECT opens up an important opportunity for quantitative assessment (e.g. via generation of kinetic parameters), it was shown to generate highly consistent perfusion information compared to established conventional imaging. Future work focuses on merging these two important capabilities.
https://fbt.tums.ac.ir/index.php/fbt/article/view/27
https://fbt.tums.ac.ir/index.php/fbt/article/download/27/26