Congress:
ECR25
Poster Number:
C-17316
Type:
Poster: EPOS Radiographer (scientific)
DOI:
10.26044/ecr2025/C-17316
Authorblock:
H. Hara1, H. Muraishi1, S. Maehira2, S. Mizukami1, T. Todoroki1, E. Ichikawa1, K. Nori1, H. Matsuda1, H. Mimura3; 1Sagamihara/JP, 2Isehara/JP, 3Kawasaki/JP
Disclosures:
Hidetake Hara:
Nothing to disclose
Hiroshi Muraishi:
Nothing to disclose
Shouta Maehira:
Nothing to disclose
Shinya Mizukami:
Nothing to disclose
Tatsuya Todoroki:
Nothing to disclose
Erii Ichikawa:
Nothing to disclose
Karin Nori:
Nothing to disclose
Hibiki Matsuda:
Nothing to disclose
Hidefumi Mimura:
Nothing to disclose
Keywords:
Emergency, Neuroradiology brain, Radiographers, CT, Experimental, Image manipulation / Reconstruction, Computer Applications-Virtual imaging, Diagnostic procedure, Imaging sequences, Ischaemia / Infarction, Kv imaging
Results
1. VMI images
Fig.7 show the simulation results of VMI at 60, 65 and 70 keV, and compared to the 120 and 140 keV-based imeges. 60 and 65 keV shows a significant increase in contrast of the lesion. With an increase in tube current, the area of the cerebral infarction can be clearly delineated and its extent (infarcted area) can be confirmed due to the decrease in noise.
Fig 7: Result of VMI CT images in 60, 65, 70 keV, obtained of 5 mm slice thickness and 120 and 140 kV, 500 mA (upper row) and 800mA (lower row). ©“Department of Radiology, Kitasato University”
2. Imaging evaluation
The results of the d'2 analysis are shown in Fig.8, the results of the CNRLO analysis in Fig.9, and the results of the FOM analysis in Fig.10. d'2 showed higher values at VMI 65-68 keV and CNRLO at VMI 60-62 keV, with higher mA being more significant. Focusing on X-ray energy, high values were observed at 140 kV, and compared to the 120 kV-based images, the d'2 was approximately 1.8 times higher. The FOM was higher with increasing mA, and around VMI 60 keV highest in 140 kV-based images.
Fig 8: Result of detectability index (d’2) in VMI images, obtained of 120 and 140 kV, 5mm slice thickness. ©“Department of Radiology, Kitasato University”
Fig 9: Result of CNRLO in VMI images, obtained of 120 and 140 kV, 5mm slice thickness.
©“Department of Radiology, Kitasato University”
Fig 10: Result of FOM in VMI images, obtained of 120 and 140 kV, 5mm slice thickness.
©“Department of Radiology, Kitasato University”
3. Photon-counting detector CT optimization
Considering the optimum conditions with photon-counting detector CT, a VMI around 60-65 keV provides in 140 kV-based images high contrast and is suitable for low contrast areas such as acute stroke (Fig.11), higher dose efficiency can be obtained by increasing the dose, but the guideline for the diagnostic reference level of exposure dose may be appropriate to use about 500 mA, which corresponds to a simple head routine of 77 mGy or less [12].
Fig 11: Comparison with 120 and 140 kV-based VMI images, obtained of detectability index (d’2), CNRLO, FOM, CTDI and Effective energy with 500 mA and 5 mm slice thickness. ©“Department of Radiology, Kitasato University”
