Improved dose calculation accuracy for low energy brachytherapy by optimizing dual energy CT imaging protocols for noise reduction using sinogram affirmed iterative reconstruction

Purpose.Dual-energy CT imaging tends to suffer from much lower signal-to-noise ratio than single-energy CT. In this paper, we propose an improved anticorrelated noise reduction (ACNR) method without causing cross-contamination artifacts.Methods.The proposed algorithm diffuses both basis material density images (e.g., water and iodine) at the same time using a novel correlated diffusion algorithm. The algorithm has been compared to the original ACNR algorithm in a contrast-enhanced, IRB-approved patient study. Material density accuracy and noise reduction are quantitatively evaluated by the percent density error and the percent noise reduction.Results.Both algorithms have significantly reduced the noises of basis material density images in all cases. The average percent noise reduction is 69.3% and 66.5% with the ACNR algorithm and the proposed algorithm, respectively. However, the ACNR algorithm alters the original material density by an average of 13% (or 2.18 mg/cc) with a maximum of 58.7% (or 8.97 mg/cc) in this study. This is evident in the water density images as massive cross-contaminations are seen in all five clinical cases. On the contrary, the proposed algorithm only changes the mean density by 2.4% (or 0.69 mg/cc) with a maximum of 7.6% (or 1.31 mg/cc). The cross-contamination artifacts are significantly minimized or absent with the proposed algorithm.Conclusion.The proposed algorithm can significantly reduce image noise present in basis material density images from dual-energy CT imaging, with minimized cross-contaminations compared to the ACNR algorithm.

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Dual-Energy CT Imaging May Play Role in Gout Diagnosis

Family Practice News ◽

10.1016/s0300-7073(09)70066-0 ◽

2009 ◽

Vol 39 (2) ◽

pp. 21

Author(s):

SHERRY BOSCHERT

Keyword(s):

Dual Energy ◽

Ct Imaging ◽

Dual Energy Ct

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Diagnostic accuracy for detection of intracranial hemorrhage using automatic tube current modulation and advanced modeled iterative reconstruction in unenhanced head single-energy and dual-energy CT

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren ◽

10.1055/s-0037-1600409 ◽

2017 ◽

Vol 189 (S 01) ◽

pp. S1-S124

Author(s):

J Scholtz ◽

J Wichmann ◽

D Bennett ◽

D Leithner ◽

M Albrecht ◽

...

Keyword(s):

Diagnostic Accuracy ◽

Intracranial Hemorrhage ◽

Iterative Reconstruction ◽

Dual Energy ◽

Dual Energy Ct ◽

Tube Current Modulation ◽

Current Modulation ◽

Automatic Tube Current Modulation ◽

Tube Current

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Dose heterogeneity correction for low-energy brachytherapy sources using dual-energy CT images

Physics in Medicine and Biology ◽

10.1088/0031-9155/59/18/5305 ◽

2014 ◽

Vol 59 (18) ◽

pp. 5305-5316 ◽

Cited By ~ 8

Author(s):

S Mashouf ◽

E Lechtman ◽

P Lai ◽

B M Keller ◽

A Karotki ◽

...

Keyword(s):

Ct Images ◽

Dual Energy ◽

Low Energy ◽

Dual Energy Ct ◽

Heterogeneity Correction

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Abstract P327: Utilizing Iodine Contrast Extravasation Post Reperfusion and Dual Energy Ct Imaging to Predict Risk of Hemorrhagic Conversion in Acute Stroke Patients

Stroke ◽

10.1161/str.52.suppl_1.p327 ◽

2021 ◽

Vol 52 (Suppl_1) ◽

Author(s):

Tri Huynh* ◽

Niran Vijayaraghavan* ◽

Hannah Branstetter ◽

Natalie Buchwald ◽

Justin De Prey ◽

...

Keyword(s):

Acute Stroke ◽

Infarct Volume ◽

Reperfusion Therapy ◽

Dual Energy ◽

Ct Imaging ◽

Dual Energy Ct ◽

Stroke Patients ◽

Post Intervention ◽

Contrast Extravasation ◽

Post Contrast

Introduction: Hyperintense acute reperfusion marker (HARM) has been identified on post-contrast magnetic resonance imaging (MRI) to be a marker of hemorrhagic conversion (HC) post reperfusion therapy in acute stroke patients. We have previously described a case where MRI HARM was mimicked on post contrast computed topography (CT) imaging in an acute stroke patient post reperfusion. Dual-Energy (DECT) allows for differentiation between acute blood and iodine contrast extravasation (ICE), and thus can have utility when ICE is present. Here we sought to validate whether post-intervention ICE/CT hyperdensity reperfusion maker (CT HARM), and contrast subtracted on DECT is associated with HC in acute stroke patients. Method: Data was obtained from our Institutional Review Board approved stroke admission database from January 2017 to November 2019, including ischemic stroke patients that received thrombolysis or thrombectomy, had evaluable images within 24 hours of admission, and received a DECT. Ischemic volumes of the stroke was measured on diffusion-weighted image (DWI). ICE was measured on CT head and DECT using the freehand 3D region of interest tool on the Visage Imaging PACS System. Susceptibility weighted MRI sequences were used to grade HC. Data analysis was conducted with regression modeling. Results: A total of 82 patients were included, 49% women, median age 73 (interquartile range (IQR), 61- 77), admission NIHSS 12 (IQR, 7 - 21), 24 hour change in NIHSS 4 (IQR, 0 -13), glucose 125 (IQR, 106 -158), creatinine 1.0 (IQR, 0.8 - 1.2), infarct volume 50.6 ± 7.1 mL, 48% treated with thrombectomy, 7% with PH-1 or PH-2 identified on MRI, and 56% with MCA infarcts. ICE volume was 2.6 ± 1.0 mL and DECT volume was 2.2 ± 1.1mL. ICE increased the likelihood of MRI confirmed PH-1 or PH-2 hemorrhagic conversion (odds ratio (OR) 14.34, 95% confidence interval (CI) 5.74 - 22.94) and decreased likelihood of increase in NIHSS at 24 hours (OR 0.20, 95% CI 0.01 to 0.40). There were no other significant associations with ICE or DECT volumes. Conclusion: Our results are supportive of our proposed association between CT HARM and risk of HC. More studies are needed to study whether quantitative of DECT can be predictive of stroke outcomes post reperfusion therapy.

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First experience with combined use of adaptive statistical iterative reconstruction and gemstone spectral imaging in spinal fusion CT images

10.7287/peerj.preprints.1306 ◽

2015 ◽

Author(s):

Fengdan Wang ◽

Yan Zhang ◽

Zhengyu Jin ◽

Richard Zwar

Keyword(s):

Image Quality ◽

Iterative Reconstruction ◽

Dual Energy ◽

Dual Energy Ct ◽

Metal Artifacts ◽

Adaptive Statistical Iterative Reconstruction ◽

Subjective Image Quality ◽

Gemstone Spectral Imaging ◽

Statistical Iterative Reconstruction ◽

Combined Use

Objective. To explore whether the image noises and the metal artifacts could be further managed by the combined use of two technologies, the adaptive statistical iterative reconstruction (ASIR) and the monochromatic imaging generated by gemstone spectral imaging (GSI) dual-energy CT. Materials and Methods. Fifty-one patients with 318 spinal pedicle screws were prospectively scanned with dual energy CT by using fast kV-switching GSI between 80 and 140 kVp. The monochromatic GSI images at 110 keV were reconstructed either without ASIR or with ASIR of various levels (30%, 50%, 70% and 100%). For these five sets of images, both objective and subjective image quality assessments were performed to evaluate the image quality. Results. With objective image quality assessment, the metal artifacts (measured by an artifacts index) significantly decreased when increasing levels of ASIR was utilized (p < 0.001). Moreover, adding ASIR to GSI also decreased the image noise (p < 0.001) and improved the signal-to-noise ratio (SNR, p < 0.001). With subjective image quality analysis, the inter-reader agreements were good, with intra-class correlation coefficients (ICC) of 0.89 to 0.99. Meanwhile, the visualization of the peri-implant soft tissue was improved at higher ASIR levels (p < 0.001). Conclusion. Combined use of ASIR and GSI is shown to decrease the image noise and improve the image quality in post-spinal fusion CT scans. Optimal results were achieved with ASIR levels of over 70%.

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