Element-level Phase Measurement of Array Antenna using Stabilized Planar Imaging System for Emerging Sub-6 GHz 5G Communications

Object The authors assessed the role of 3D anisotropy contrast (3DAC) in evaluating specific ascending tract degeneration in patients with cervical spondylotic myelopathy (CSM). Methods The authors studied 10 patients (2 women, 8 men; mean age 59.8 ± 14.6 years) with CSM and spinal cord compression below the C2–3 disc level, as well as 10 healthy control individuals (3 women, 7 men; mean age 42.0 ± 24.1 years). Images of the cervical cord at the C2–3 level were obtained using a 3.0-T MR imaging system. Results Three-dimensional anisotropy contrast imaging clearly made possible tract-by-tract analysis of the fasciculus cuneatus, fasciculus gracilis, and spinocerebellar tract. Tract degeneration identified using 3DAC showed good correlation with a decline in fractional anisotropy. Degeneration of the fasciculus gracilis detected by “vector contrast” demonstrated a good correlation with Nurick grades. Conclusions The study unambiguously demonstrated that 3DAC imaging is capable of assessing ascending tract degeneration in patients with CSM. Degeneration of an individual tract can be easily identified as a vector contrast change on the 3DAC image, a reflection of quantitative changes in anisotropism, similar to fractional anisotropy. Excellent correlation between Nurick grades and fasciculus gracilis degeneration suggests potential application of 3DAC imaging for tract-by-tract clinical correlation.

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Gamma Radiation Imaging System via Variable and Time-Multiplexed Pinhole Arrays

Sensors ◽

10.3390/s20113013 ◽

2020 ◽

Vol 20 (11) ◽

pp. 3013 ◽

Cited By ~ 1

Author(s):

Ariel Schwarz ◽

Amir Shemer ◽

Yossef Danan ◽

Rachel Bar-Shalom ◽

Hemy Avraham ◽

...

Keyword(s):

Gamma Radiation ◽

Imaging System ◽

Single Photon ◽

Photon Emission ◽

Three Dimensional ◽

Medical Diagnostics ◽

Emission Computed Tomography ◽

Planar Imaging ◽

Gamma Imaging ◽

Image Capturing

Biomedical planar imaging using gamma radiation is a very important screening tool for medical diagnostics. Since lens imaging is not available in gamma imaging, the current methods use lead collimator or pinhole techniques to perform imaging. However, due to ineffective utilization of the gamma radiation emitted from the patient’s body and the radioactive dose limit in patients, poor image signal to noise ratio (SNR) and long image capturing time are evident. Furthermore, the resolution is related to the pinhole diameter, thus there is a tradeoff between SNR and resolution. Our objectives are to reduce the radioactive dose given to the patient and to preserve or improve SNR, resolution and capturing time while incorporating three-dimensional capabilities in existing gamma imaging systems. The proposed imaging system is based on super-resolved time-multiplexing methods using both variable and moving pinhole arrays. Simulations were performed both in MATLAB and GEANT4, and gamma single photon emission computed tomography (SPECT) experiments were conducted to support theory and simulations. The proposed method is able to reduce the radioactive dose and image capturing time and to improve SNR and resolution. The results and method enhance the gamma imaging capabilities that exist in current systems, while providing three-dimensional data on the object.

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Microdose acquisition in adolescent leg length discrepancy using a low-dose biplane imaging system

Acta Radiologica ◽

10.1177/0284185116682381 ◽

2017 ◽

Vol 58 (9) ◽

pp. 1108-1114 ◽

Cited By ~ 2

Author(s):

Janni Jensen ◽

Bo R Mussmann ◽

John Hjarbæk ◽

Zaid Al-Aubaidi ◽

Niels W Pedersen ◽

...

Keyword(s):

Low Dose ◽

Imaging System ◽

Statistical Significance ◽

Leg Length Discrepancy ◽

Leg Length ◽

Planar Imaging ◽

Length Discrepancy ◽

Significant Difference ◽

Length Measurements ◽

Total Leg

Background Children with leg length discrepancy often undergo repeat imaging. Therefore, every effort to reduce radiation dose is important. Using low dose preview images and noise reduction software rather than diagnostic images for length measurements might contribute to reducing dose. Purpose To compare leg length measurements performed on diagnostic images and low dose preview images both acquired using a low-dose bi-planar imaging system. Material and Methods Preview and diagnostic images from 22 patients were retrospectively collected (14 girls, 8 boys; mean age, 12.8 years; age range, 10–15 years). All images were anonymized and measured independently by two musculoskeletal radiologists. Three sets of measurements were performed on all images; the mechanical axis lines of the femur and the tibia as well as the anatomical line of the entire extremity. Statistical significance was tested with a paired t-test. Results No statistically significant difference was found between measurements performed on the preview and on the diagnostic image. The mean tibial length difference between the observers was −0.06 cm (95% confidence interval [CI], −0.12 to 0.01) and −0.08 cm (95% CI, −0.21 to 0.05), respectively; 0.10 cm (95% CI, 0.02–0.17) and 0.06 cm (95% CI, −0.02 to 0.14) for the femoral measurements and 0.12 cm (95% CI, −0.05 to 0.26) and 0.08 cm (95% CI, −0.02 to 0.19) for total leg length discrepancy. ICCs were >0.99 indicating excellent inter- and intra-rater reliability. Conclusion The data strongly imply that leg length measurements performed on preview images from a low-dose bi-planar imaging system are comparable to measurements performed on diagnostic images.

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