TY - JOUR
T1 - Determination of iodine detectability in different types of multiple-energy images for a photon-counting detector computed tomography system
AU - Zhou, Wei
AU - Michalak, Gregory
AU - Weaver, Jayse
AU - Ferrero, Andrea
AU - Gong, Hao
AU - Fetterly, Kenneth A.
AU - McCollough, Cynthia H.
AU - Leng, Shuai
N1 - Funding Information:
The research reported in this article was supported by the U.S. National Institutes of Health under Award Nos. R01 EB016966 and C06 RR018898. The content is solely the responsibility of the authors and does not necessarily represent the official views of the U.S. National Institutes of Health. The equipment described in this work is a research device that is not intended to become commercially available.
Publisher Copyright:
© 2019 Society of Photo-Optical Instrumentation Engineers (SPIE).
PY - 2019/10/1
Y1 - 2019/10/1
N2 - In addition to low-energy-threshold images (TLIs), photon-counting detector (PCD) computed tomography (CT) can generate virtual monoenergetic images (VMIs) and iodine maps. Our study sought to determine the image type that maximizes iodine detectability. Adult abdominal phantoms with iodine inserts of various concentrations and lesion sizes were scanned on a PCD-CT system. TLIs, VMIs at 50 keV, and iodine maps were generated, and iodine contrast-to-noise ratio (CNR) was measured. A channelized Hotelling observer was used to determine the area under the receiver-operating-characteristic curve (AUC) for iodine detectability. Iodine map CNR (0.57 ± 0.42) was significantly higher (P < 0.05) than for TLIs (0.46 ± 0.26) and lower (P < 0.001) than for VMIs at 50 keV (0.74 ± 0.33) for 0.5 mgI/cc and a 35-cm phantom. For the same condition and an 8-mm lesion, iodine detectability from iodine maps (AUC = 0.95 ± 0.01) was significantly lower (P < 0.001) than both TLIs (AUC = 0.99 ± 0.00) and VMIs (AUC = 0.99 ± 0.01). VMIs at 50 keV had similar detectability to TLIs and both outperformed iodine maps. The lowest detectable iodine concentration was 0.5 mgI/cc for an 8-mm lesion and 1.0 mgI/cc for a 4-mm lesion.
AB - In addition to low-energy-threshold images (TLIs), photon-counting detector (PCD) computed tomography (CT) can generate virtual monoenergetic images (VMIs) and iodine maps. Our study sought to determine the image type that maximizes iodine detectability. Adult abdominal phantoms with iodine inserts of various concentrations and lesion sizes were scanned on a PCD-CT system. TLIs, VMIs at 50 keV, and iodine maps were generated, and iodine contrast-to-noise ratio (CNR) was measured. A channelized Hotelling observer was used to determine the area under the receiver-operating-characteristic curve (AUC) for iodine detectability. Iodine map CNR (0.57 ± 0.42) was significantly higher (P < 0.05) than for TLIs (0.46 ± 0.26) and lower (P < 0.001) than for VMIs at 50 keV (0.74 ± 0.33) for 0.5 mgI/cc and a 35-cm phantom. For the same condition and an 8-mm lesion, iodine detectability from iodine maps (AUC = 0.95 ± 0.01) was significantly lower (P < 0.001) than both TLIs (AUC = 0.99 ± 0.00) and VMIs (AUC = 0.99 ± 0.01). VMIs at 50 keV had similar detectability to TLIs and both outperformed iodine maps. The lowest detectable iodine concentration was 0.5 mgI/cc for an 8-mm lesion and 1.0 mgI/cc for a 4-mm lesion.
KW - Channelized Hotelling observer
KW - Iodine detectability
KW - Iodine maps
KW - Photon-counting detector computed tomography
KW - Virtual monoenergetic images
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U2 - 10.1117/1.JMI.6.4.043501
DO - 10.1117/1.JMI.6.4.043501
M3 - Article
AN - SCOPUS:85073738861
SN - 2329-4302
VL - 6
JO - Journal of Medical Imaging
JF - Journal of Medical Imaging
IS - 4
M1 - 043501
ER -