CASE: 58 year old male presented with a liver lesion seen on prior imaging. A dual energy scan was performed to further characterize the lesion. Volumetric Dual Energy scans were performed following the injection of 80mls of contrast. Scans were performed during Arterial Phase, early Portal Phase and Delayed at 3mins. Monochromatic images, iodine maps and virtual non contrast images were generated for review.

1. ©2015 TOSHIBA MEDICAL SYSTEMS56 | VISIONS25
1) Harbin No 4 Hospital,
China
CASE STUDY COMPUTED TOMOGRAPHY
Volumetric Dual Energy, liver, Hepato-Callular Carcinoma
Dual Energy
ScanMode Collimation kVp mAs
Rotation
Time(s)
ScanRange
(mm)
DoseReduction
CTDIvol
(mGy)
DLP
(mGy.cm)
Effective
Dose(mSv)
k
Arterial Dual Energy 0.5mm x 320 80/135 SUREExposure 3D 0.5 160 AIDR 3D Standard 10.5 167.9 2.52 0.015
Early Portal Dual Energy 0.5mm x 320 80/135 SUREExposure 3D 0.5 160 AIDR 3D Standard 10.5 167.9 2.52 0.015
3 min Delay Dual Energy 0.5mm x 320 80/135 SUREExposure 3D 0.5 160 AIDR 3D Standard 10.5 167.9 2.52 0.015
This 58 year old male presented with a liver lesion seen on prior imaging. A dual energy
scan was performed to further characterize the lesion. Volumetric Dual Energy scans
were performed following the injection of 80mls of contrast. Scans were performed
during Arterial Phase, early Portal Phase and Delayed at 3mins. Monochromatic images,
iodine maps and virtual non contrast images were generated for review.
Dr S. Dong Cao 1)
Dr. Shao Dong Coa
Arterial Phase Early Portal Phase
70keV Monochromatic Image
Iodine Map
3min Delay Phase

2. VISIONS25 | 57CTEU140097
SUMMARY
The lesion demonstrates characteristics consistent with
a Hepato-Cellular Carcinoma (HCC). These lesions have
intense arterial enhancement, fast washout and then
become homogeneous with normal liver. Raw data
based dual energy provides high quality monochromatic
images at 70keV which correspond to a routine 120kVp
image allowing adjacent structures to be reviewed as
usual. The iodine maps provide easy visualization and
quantification of the lesion.
This case demonstrates that volumetric dual energy
can be implemented into dedicated liver imaging pro-
tocols with good image quality in multiple phases at a
reasonable radiation dose. Additional information is pro-
vided by the iodine maps.
Virtual Non Contrast images generated in the early venous phase demonstrate lesion homogeneity
What is dual energy?
CT imaging is based on the principle that various anatomical structures within the
body attenuate X-rays differently. Unfortunately, structures with similar Hounsfield
units (i.e. CT numbers) remain very difficult to differentiate from each other. However,
structures that produce similar Hounsfield units at one beam energy may respond
differentlyatadifferentbeamenergy.Dualenergyscanningcanincreasetheamount
of information available from CT imaging. Iodine maps can be generated by analyz-
ing images acquired at both high kVp and low kVp, providing functional information
about tissue.
As said Dual-energy helical scanning alternates between high and low kV with each
gantryrotation.AlsothemAisautomaticallyadjustedforthetwodifferentenergiesto
ensure a matched signal-to- noise ratio which increases the accuracy of dual energy
analysis. Also the tube exposure can be manually turned OFF in the upper 180 degree
ofthegantryrotationthatwouldexposetheventralsideofthepatientandpotentially
more radiation sensitive areas such as breast tissue in females.
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