Achieving high-resolution soft-tissue imaging with cone-beam CT: a two-pronged approach for modulation of x-ray fluence and detector gain

Abstract Background Elbow imaging is challenging with conventional multidetector computed tomography (MDCT), while cone-beam CT (CBCT) provides superior options. We compared intra-individually CBCT versus MDCT image quality in cadaveric elbows. Methods A twin robotic x-ray system with new CBCT mode and a high-resolution clinical MDCT were compared in 16 cadaveric elbows. Both systems were operated with a dedicated low-dose (LD) protocol (equivalent volume CT dose index [CTDIvol(16 cm)] = 3.3 mGy) and a regular clinical scan dose (RD) protocol (CTDIvol(16 cm) = 13.8 mGy). Image quality was evaluated by two radiologists (R1 and R2) on a seven-point Likert scale, and estimation of signal intensity in cancellous bone was conducted. Wilcoxon signed-rank tests and intraclass correlation coefficient (ICC) statistics were used. Results The CBCT prototype provided superior subjective image quality compared to MDCT scans (for RD, p ≤ 0.004; for LD, p ≤ 0.001). Image quality was rated very good or excellent in 100% of the cases by both readers for RD CBCT, 100% (R1) and 93.8% (R2) for LD CBCT, 62.6% and 43.8% for RD MDCT, and 0.0% and 0.0% for LD MDCT. Single-measure ICC was 0.95 (95% confidence interval 0.91–0.97; p < 0.001). Software-based assessment supported subjective findings with less “undecided” pixels in CBCT than dose-equivalent MDCT (p < 0.001). No significant difference was found between LD CBCT and RD MDCT. Conclusions In cadaveric elbow studies, the tested cone-beam CT prototype delivered superior image quality compared to high-end multidetector CT and showed a potential for considerable dose reduction.

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High-performance soft-tissue imaging in extremity cone-beam CT

10.1117/12.2043463 ◽

2014 ◽

Cited By ~ 4

Author(s):

W. Zbijewski ◽

A. Sisniega ◽

J. W. Stayman ◽

A. Muhit ◽

G. Thawait ◽

...

Keyword(s):

Soft Tissue ◽

High Performance ◽

Cone Beam Ct ◽

Tissue Imaging ◽

Cone Beam

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Improving soft tissue imaging with volume-of-interest cone-beam CT

10.32920/ryerson.14651949 ◽

2021 ◽

Author(s):

Christopher Huynh Huynh

Keyword(s):

Soft Tissue ◽

Cone Beam Ct ◽

Field Size ◽

Tissue Imaging ◽

Cone Beam ◽

Projection Data ◽

Full Field ◽

Volume Of Interest ◽

Photon Fluence ◽

Intermediate Image

Current cone-beam CT systems acquire full field-of-view projections in which x-ray scatter degrades the contrast of soft-tissue in the reconstructed images. The objective of this work was to simulate volume-of-interest (VOI) imaging, which reduces scatter and dose to the patient through beam collimation, to investigate the improvements in soft-tissue visibility on the Gamma Knife Icon. The results indicated that as field size decreased, contrast and noise increased, leading to only modest improvements in the contrast-to-noise ratio when using the same initial photon fluence. A reconstruction framework called the interior virtual method was adapted to suppress truncation-induced artifacts and noise in the VOI image. In this framework the projection data were extrapolated using a cosine function, an intermediate image was reconstructed analytically, and virtual projections of the intermediate image were created for iterative reconstruction. The framework supports high quality VOI reconstruction and can allow clinicians to optimize dose for soft-tissue visualization.

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Simpler and effective radiological evaluations for modiolar proximity of a slim modiolar cochlear implant electrode

Scientific Reports ◽

10.1038/s41598-020-74738-x ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Sang-Yeon Lee ◽

Jin Hee Han ◽

Marge Carandang ◽

Yun Jung Bae ◽

Byung Yoon Choi

Keyword(s):

High Resolution ◽

Cone Beam Ct ◽

Cone Beam ◽

Metal Artifact ◽

Insertion Technique ◽

X Ray ◽

Discrimination Capability ◽

Electrode Distance ◽

Efficient Measurement ◽

Conventional Ct

Abstract A new slim modiolar electrode (CI532/632) has been reported to ensure better modiolar proximity than conventional electrodes. Better modiolar proximity has been proposed to yield better electrode discrimination capability and potentially better speech outcomes, necessitating its efficient measurement. Currently, intracochlear positional index (ICPI), the most reliable indicator for evaluating modiolar proximity, has been measured exclusively through ‘metal artifact-less’ cone beam CT. However, popular use of this index is precluded due to lack of cone beam CT in many institutions. Thus, eyes are now on elucidation of easy-to-measure indicators of modiolar proximity derived from conventional CT, which is accessible in all centers. We observed that enhanced tomographic resolution significantly reduces partial volume artifacts, providing better visualization of modiolus-electrode distance. Aided by ultra-high kernel specification with high-resolution index, we developed a novel and easy-to-measure, conventional CT-specific indicator, “modified ICPI”, for evaluation of modiolar proximity. Further, we showed that it closely correlates with the previously proposed parameter of modiolar proximity, the spiral diameter, measured from post-insertion radiograph, reiterating the value of X-ray-based spiral diameter. Through this study, we have taken a step toward the stage of immediate visual feedback regarding modiolar proximity and changes in insertion technique intraoperatively, ensuring optimal modiolar proximity.

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Soft-tissue imaging in low-dose, C-arm cone-beam CT using statistical image reconstruction

10.1117/12.2008421 ◽

2013 ◽

Cited By ~ 4

Author(s):

Adam S. Wang ◽

Sebastian Schafer ◽

J. W. Stayman ◽

Yoshi Otake ◽

Marc S. Sussman ◽

...

Keyword(s):

Soft Tissue ◽

Image Reconstruction ◽

Low Dose ◽

Cone Beam Ct ◽

Tissue Imaging ◽

Cone Beam ◽

Statistical Image Reconstruction

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Soft-tissue imaging with C-arm cone-beam CT using statistical reconstruction

Physics in Medicine and Biology ◽

10.1088/0031-9155/59/4/1005 ◽

2014 ◽

Vol 59 (4) ◽

pp. 1005-1026 ◽

Cited By ~ 44

Author(s):

Adam S Wang ◽

J Webster Stayman ◽

Yoshito Otake ◽

Gerhard Kleinszig ◽

Sebastian Vogt ◽

...

Keyword(s):

Soft Tissue ◽

Cone Beam Ct ◽

Tissue Imaging ◽

Cone Beam ◽

Statistical Reconstruction

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Improving soft tissue imaging with volume-of-interest cone-beam CT

10.32920/ryerson.14651949.v1 ◽

2021 ◽

Author(s):

Christopher Huynh Huynh

Keyword(s):

Soft Tissue ◽

Cone Beam Ct ◽

Field Size ◽

Tissue Imaging ◽

Cone Beam ◽

Projection Data ◽

Full Field ◽

Volume Of Interest ◽

Photon Fluence ◽

Intermediate Image

Current cone-beam CT systems acquire full field-of-view projections in which x-ray scatter degrades the contrast of soft-tissue in the reconstructed images. The objective of this work was to simulate volume-of-interest (VOI) imaging, which reduces scatter and dose to the patient through beam collimation, to investigate the improvements in soft-tissue visibility on the Gamma Knife Icon. The results indicated that as field size decreased, contrast and noise increased, leading to only modest improvements in the contrast-to-noise ratio when using the same initial photon fluence. A reconstruction framework called the interior virtual method was adapted to suppress truncation-induced artifacts and noise in the VOI image. In this framework the projection data were extrapolated using a cosine function, an intermediate image was reconstructed analytically, and virtual projections of the intermediate image were created for iterative reconstruction. The framework supports high quality VOI reconstruction and can allow clinicians to optimize dose for soft-tissue visualization.

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A Method to Improve Electron Density Measurement of Cone-Beam CT Using Dual Energy Technique

BioMed Research International ◽

10.1155/2015/858907 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Kuo Men ◽

Jian-Rong Dai ◽

Ming-Hui Li ◽

Xin-Yuan Chen ◽

Ke Zhang ◽

...

Keyword(s):

Electron Density ◽

Cone Beam Ct ◽

Density Measurement ◽

Dual Energy ◽

Cone Beam ◽

Imaging Method ◽

Basis Material ◽

X Ray ◽

Dual Energy Imaging ◽

Set Up

Purpose. To develop a dual energy imaging method to improve the accuracy of electron density measurement with a cone-beam CT (CBCT) device.Materials and Methods. The imaging system is the XVI CBCT system on Elekta Synergy linac. Projection data were acquired with the high and low energy X-ray, respectively, to set up a basis material decomposition model. Virtual phantom simulation and phantoms experiments were carried out for quantitative evaluation of the method. Phantoms were also scanned twice with the high and low energy X-ray, respectively. The data were decomposed into projections of the two basis material coefficients according to the model set up earlier. The two sets of decomposed projections were used to reconstruct CBCT images of the basis material coefficients. Then, the images of electron densities were calculated with these CBCT images.Results. The difference between the calculated and theoretical values was within 2% and the correlation coefficient of them was about 1.0. The dual energy imaging method obtained more accurate electron density values and reduced the beam hardening artifacts obviously.Conclusion. A novel dual energy CBCT imaging method to calculate the electron densities was developed. It can acquire more accurate values and provide a platform potentially for dose calculation.

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