Reduction of iodine load in CT imaging of pancreas acquired with low tube voltage and an adaptive statistical iterative reconstruction technique.
OBJECTIVE
To prospectively assess the contrast enhancement, image quality, radiation dose, and detectability of malignant pancreatic tumors with pancreatic computed tomography (CT) obtained at an 80-kilovolt (peak) (kV[p]) tube voltage setting and reduced iodine dose.


METHODS
Institutional review board approval and written informed consent were obtained. During a recent 10-month period, 136 patients (66 men and 70 women; age range, 21-86 years; mean ± SD age, 65.9 ± 11.0 years) with suspected pancreatic disease were randomized into 3 groups according to the following iodine-load and tube-voltage protocols: 600 mg of iodine per kilogram body weight (mg/kg) and 120 kV(p) (600-120 group), 500 mg/kg and 80 kV(p) (500-80 group), and 400 mg/kg and 80 kV(p) (400-80 group). Analysis of variance was conducted to evaluate differences in CT number, background noise, signal-to-noise ratio, effective dose, lesion-to-pancreas contrast-to-noise ratio, and figure of merit. Sensitivity, specificity, and area under the receiver-operating-characteristic curve were compared to assess the detectability of malignant pancreatic tumors.


RESULTS
The signal-to-noise ratios in vessels were greater (P < 0.05) in the 400-80 and 500-80 groups than in the 600-120 group, and those in pancreas were comparable between the 400-80 and 600-120 groups. No significant difference was found in effective dose, image quality, lesion-to-pancreas contrast-to-noise ratio, or figure of merit between the groups. Sensitivity, specificity, and area under the receiver-operating-characteristic curve for detecting malignant pancreatic tumors were comparable between the groups.


CONCLUSIONS
Pancreatic CT with an 80-kV(p) setting and 400-mg iodine per kilogram contrast material load facilitates the reduction of iodine dose while maintaining image quality and the detectability of malignant pancreatic tumors.
From the Departments of *Radiology and †Radiology Services, Gifu University Hospital, Gifu, Japan; and ‡Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA.
Yoshifumi
Y
Noda
Masayuki
M
Kanematsu
Satoshi
S
Goshima
Hiroshi
H
Kondo
Haruo
H
Watanabe
Hiroshi
H
Kawada
Nobuyuki
N
Kawai
Yukichi
Y
Tanahashi
Toshiharu
T
Miyoshi
Kyongtae T
KT
Bae
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003287:Contrast Media / Q000008:administration & dosage; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D007455:Iodine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging*; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
D003287:Contrast Media; D007455:Iodine