Improvement of image quality at low-radiation dose and low-contrast material dose abdominal CT in patients with cirrhosis: intraindividual comparison of low tube voltage with iterative reconstruction algorithm and standard tube voltage.
OBJECTIVE
To intraindividually compare a low-tube voltage, low-contrast material dose computed tomography (CT) reconstructed with iterative reconstruction (IR) algorithm at standard tube voltage reconstructed with filtered back projection (FBP) and standard-contrast material dose during liver dynamic CT.


METHODS
Twenty-five patients with liver cirrhosis underwent 64-section multidetector CT. One hundred twenty kilovolt (peak) (kV[p]) with standard contrast material dose of 600 mg of iodine per kilogram (protocol A) and 80 kV(p) with low-contrast material dose of 450 mg of iodine per kilogram (protocol B) CT image sets were reconstructed by using FBP algorithm and that of using IR algorithm with a 60%/40% blend of IR-FBP reconstruction at 80-kV(p) image set (protocol C). Scans obtained during 3 hepatic phases were subjected to quantitative and qualitative analysis.


RESULTS
The mean radiation dose and the contrast medium dose were significantly lower under protocols B and C than under protocol A. In all hepatic phases, all signal-to-noise and contrast-to-noise ratios were greater under protocol C than under other protocols at all anatomic sites. Qualitative analysis showed that image noise and diagnostic acceptability were significantly higher under protocol C.


CONCLUSIONS
In all hepatic phases, a low-tube voltage, low-contrast material dose CT with IR algorithm yielded better contrast enhancement and image quality than a standard tube voltage, standard contrast material dose CT with FBP in thin adult patients.
Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan. namimottoo@yahoo.co.jp
Tomohiro
T
Namimoto
Seitaro
S
Oda
Daisuke
D
Utsunomiya
Toshiaki
T
Shimonobo
Sosuke
S
Morita
Takeshi
T
Nakaura
Yasuyuki
Y
Yamashita
D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001706:Biopsy; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007479:Iopamidol / Q000008:administration & dosage*; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging*; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D011860:Radiography, Abdominal / Q000295:instrumentation / Q000379:methods*; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*
D003287:Contrast Media; D007479:Iopamidol