Refraction and time of flight corrections in 3D ultrasound computed tomography

2010 ◽  
Author(s):  
Andreas Koch ◽  
Christian Hansen ◽  
Nils Huttebrauker ◽  
Helmut Ermert
Keyword(s):  
Computed Tomography ◽  
Time Of Flight ◽  
3D Ultrasound ◽  
Ultrasound Computed Tomography

A Prior-Information-Based Combination Solution for Picking the Difference of Time-of-Flight in Ultrasound Computed Tomography

2020 ◽  
Vol 10 (3) ◽  
pp. 763-768 ◽  
Author(s):  
Xiaoyue Fang ◽  
Junjie Song ◽  
Kuolin Liu ◽  
Yun Wu ◽  
Qiude Zhang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Sound Speed ◽  
Mean Squared Error ◽  
Median Filter ◽  
Time Of Flight ◽  
Disease Diagnosis ◽  
Phantom Experiment ◽  
Squared Error ◽  
Ultrasound Computed Tomography ◽  
The Difference

Sound speed imaging is one modal of ultrasound computed tomography (USCT) which is helpful for early breast disease diagnosis. One of the most critical processes of sound speed reconstruction is time-of-flight picking. As each of the traditional time-of-flight picking methods has shortcomings for real data, in this study, a practical priorinformation-based combination (PIBC) solution for picking the difference of time-of-flight between the reference data and the object data (DTOF) is proposed to enhance the reconstruction accuracy and uniformity. By using DTOF, some system bias will be effectively alleviated. Firstly, by analyzing the signal-amplitude, the "penetrating-through-the-object" and the "bypassing-the-object" signals are distinguished. Then for the "penetrating-throughthe-object" signals, based on the 'majority rule,' the consistency of DTOF picked by different methods are calculated as a basis to combine the advantages of different picking methods; for the "bypassing-the-object" signals, the DTOF closest to zero is chosen. Finally, the DTOFs are post-processed to suppress the noise by a median filter and to fix the deficiency of the system by an interpolation operator. The new solution is verified by in vitro breast phantom experiment conducted on the home-made USCT system "Lucid." The proposed PIBC solution can quantitatively decrease Root Mean Squared Error (RMSE) and Mean Squared Error (MSE) of DTOF picking and enhance the image quality of reconstructed sound speed images with higher accuracy and uniformity. This work is significant for ray-based sound speed reconstruction and can provide a fine initial solution for high-resolution wave-based reconstruction.

Comparison of Four Forward Models for Breast Imaging in Ultrasound Computed Tomography

2019 ◽  
Vol 28 (4) ◽  
pp. 805-816 ◽  
Author(s):  
Ruijing Li ◽  
Houjin Chen ◽  
Yahui Peng ◽  
Jupeng Li
Keyword(s):  
Computed Tomography ◽  
Breast Imaging ◽  
Forward Models ◽  
Ultrasound Computed Tomography

scholarly journals Three-dimensional ultrasound for knee osteophyte depiction: a comparative study to computed tomography

2021 ◽  
Author(s):  
Valeria Vendries ◽  
Tamas Ungi ◽  
Jordan Harry ◽  
Manuela Kunz ◽  
Jana Podlipská ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Automatic Segmentation ◽  
Three Dimensional ◽  
3D Ultrasound ◽  
Surgical Interventions ◽  
Structured Light Scanner ◽  
Joint Surfaces ◽  
Operative Planning ◽  
Rms Error ◽  
Tissue Characteristics

Abstract Purpose Osteophytes are common radiographic markers of osteoarthritis. However, they are not accurately depicted using conventional imaging, thus hampering surgical interventions that rely on pre-operative images. Studies have shown that ultrasound (US) is promising at detecting osteophytes and monitoring the progression of osteoarthritis. Furthermore, three-dimensional (3D) ultrasound reconstructions may offer a means to quantify osteophytes. The purpose of this study was to compare the accuracy of osteophyte depiction in the knee joint between 3D US and conventional computed tomography (CT). Methods Eleven human cadaveric knees were pre-screened for the presence of osteophytes. Three osteoarthritic knees were selected, and then, 3D US and CT images were obtained, segmented, and digitally reconstructed in 3D. After dissection, high-resolution structured light scanner (SLS) images of the joint surfaces were obtained. Surface matching and root mean square (RMS) error analyses of surface distances were performed to assess the accuracy of each modality in capturing osteophytes. The RMS errors were compared between 3D US, CT and SLS models. Results Average RMS error comparisons for 3D US versus SLS and CT versus SLS models were 0.87 mm ± 0.33 mm (average ± standard deviation) and 0.95 mm ± 0.32 mm, respectively. No statistical difference was found between 3D US and CT. Comparative observations of imaging modalities suggested that 3D US better depicted osteophytes with cartilage and fibrocartilage tissue characteristics compared to CT. Conclusion Using 3D US can improve the depiction of osteophytes with a cartilaginous portion compared to CT. It can also provide useful information about the presence and extent of osteophytes. Whilst algorithm improvements for automatic segmentation and registration of US are needed to provide a more robust investigation of osteophyte depiction accuracy, this investigation puts forward the potential application for 3D US in routine diagnostic evaluations and pre-operative planning of osteoarthritis.

scholarly journals Vasitis: clinical and ultrasound confusion with inguinal hernia clarified by computed tomography

2013 ◽  
Vol 5 (4) ◽  
pp. 74
Author(s):  
Kathleen Eddy ◽  
Bruce Piercy ◽  
Richard Eddy
Keyword(s):  
Computed Tomography ◽  
Inguinal Hernia ◽  
Spermatic Cord ◽  
Vas Deferens ◽  
The Other ◽  
Other Hand ◽  
Ultrasound Computed Tomography ◽  
Ultrasound Findings ◽  
Duplex Doppler

Vasitis or inflammation of the vas deferens is a rarely describedcondition categorized by Chan & Schlegel1 as either generallyasymptomatic vasitis nodosa or the acutely painful infectious vasitis.Clinically, infectious vasitis presents with nonspecific symptomsof localized pain and swelling that can be confused with other,more common conditions such as epididymitis, orchitis, testiculartorsion, and inguinal hernia. Ultrasound with duplex Doppler scanningcan be used to exclude epididymitis, orchitis, and testiculartorsion. On the other hand, while inguinal hernia is difficult todifferentiate from vasitis using ultrasound, computed tomography(CT) is diagnostic. We describe 2 cases of vasitis with clinicaland ultrasound findings that initially were interpreted as inguinalhernias. In both patients, CT was diagnostic for vasitis showing anedematous spermatic cord and no hernia. Urine cultures in bothpatients were negative, but the symptoms resolved with antibiotictreatment.

A feasibility study of time of flight cone beam computed tomography imaging

2021 ◽  
pp. 1-14
Author(s):  
Ignacio O. Romero ◽  
Changqing Li
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Time Of Flight ◽  
Cone Beam ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Effects ◽  
Breast Phantom ◽  
Scatter Reduction ◽  
Strong Scattering

BACKGROUND: The time of flight (TOF) cone beam computed tomography (CBCT) was recently shown to reduce the X-ray scattering effects by 95%and improve the image CNR by 110%for large volume objects. The advancements in X-ray sources like in compact Free Electron Lasers (FEL) and advancements in detector technology show potential for the TOF method to be feasible in CBCT when imaging large objects. OBJECTIVE: To investigate feasibility and efficacy of TOF CBCT in imaging smaller objects with different targets such as bones and tumors embedded inside the background. METHODS: The TOF method used in this work was verified using a 24cm phantom. Then, the GATE software was used to simulate the CBCT imaging of an 8 cm diameter cylindrical water phantom with two bone targets using a modeled 20 keV quasi-energetic FEL source and various TOF resolutions ranging from 1 to 1000 ps. An inhomogeneous breast phantom of similar size with tumor targets was also imaged using the same system setup. RESULTS: The same results were obtained in the 24cm phantom, which validated the applied CBCT simulation approach. For the case of 8cm cylindrical phantom and bone target, a TOF resolution of 10 ps improved the image contrast-to-noise ratio (CNR) by 57%and reduced the scatter-to-primary ratio (SPR) by 8.63. For the case of breast phantom and tumor target, image CNR was enhanced by 12%and SPR was reduced by 1.35 at 5 ps temporal resolution. CONCLUSIONS: This study indicates that a TOF resolution below 10 ps is required to observe notable enhancements in the image quality and scatter reduction for small objects around 8cm in diameter. The strong scattering targets such as bone can result in substantial improvements by using TOF CBCT.

scholarly journals Mucinous Neoplasm of the Appendix as a Mimic of Cystic Adnexal Pathology

2018 ◽  
Vol 8 ◽  
pp. 32 ◽  
Author(s):  
Chris Hutchinson ◽  
Jonathan Lyske ◽  
Vimal Patel ◽  
Gavin Low
Keyword(s):  
Magnetic Resonance Imaging ◽  
Computed Tomography ◽  
Mucinous Tumor ◽  
Imaging Findings ◽  
Resonance Imaging ◽  
Mucinous Neoplasm ◽  
Ultrasound Computed Tomography ◽  
Adnexal Pathology

Pelvic pain presents a common diagnostic conundrum with a myriad of causes ranging from benign and trivial to malignant and emergent. We present a case where a mucinous neoplasm of the appendix acted as a mimic for tubular adnexal pathology on imaging. With the associated imaging findings on ultrasound, computed tomography, and magnetic resonance imaging, we wish to raise awareness of mucinous tumors of the appendix when tubular right adnexal pathology is present both in the presence of pelvic or abdominal pain or when noted incidentally. Tubular pathology such as uncomplicated paraovarian cysts or hydrosalpinx is frequently treated conservatively with long-interval follow-up imaging or left to clinical follow-up. Thus, if incorrectly diagnosed as tubular pathology, an appendix mucocele or mucinous neoplasm of the appendix is likely to be undertreated. We wish to clarify some of the confusion around nomenclature and classification of the multiple entities that are comprised by the terms mucocele and mucinous tumor of the appendix.

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