A low-kilovolt (peak) high-tube current technique improves venous enhancement and reduces the radiation dose at indirect multidetector-row CT venography: initial experience.
OBJECTIVE
The purpose was to evaluate the image noise, contrast-to-noise ratio, and radiation dose at indirect multidetector-row computed tomographic venography (CTV) using a low-kilovolt (peak) (kV[p]) high-tube current technique.


METHODS
Thirty patients underwent indirect CTV of the lower extremity at 120 kV(p) with 170 mA and at 80 kV(p) with 426 mA (CT dose index volumes 11.8 and 9.0 mGy, respectively) on a 64-detector CT scanner. We assessed CT numbers, image noise, and contrast-to-noise ratio of deep (femoral and popliteal) veins.


RESULTS
The mean (SD) CT numbers of the femoral and popliteal veins were significantly greater at 80 kV(p) than at 120 kV(p) (142.8 [24.5] and 147.0 [19.4] Hounsfield units [HU], respectively, vs 93.1 [15.5] and 105.0 [14.9] HU, respectively; P < 0.01). The mean (SD) image noise was significantly higher at 80 kV(p) than at 120 kV(p) (11.6 [2.6] and 7.4 [1.4] HU, respectively, vs 8.9 [1.6] and 6.2 [1.5] HU, respectively; P < 0.01). Contrast-to-noise ratios at the femoral and popliteal veins were significantly higher at 80 kV(p) than at 120 kV(p) (6.0 [2.2] and 9.7 [2.4], respectively vs 3.3 [1.8] and 6.9 [2.5], respectively; P < 0.01).


CONCLUSIONS
At indirect CTV, 80 kV(p) and a high tube current setting yielded significantly improved image quality at a reduced radiation dose compared with 120 kV(p).
Diagnostic Radiology, Amakusa Medical Center, Amakusa, Japan. kff00712@nifty.com
Takeshi
T
Nakaura
Kazuo
K
Awai
Seitaro
S
Oda
Yumi
Y
Yanaga
Tomohiro
T
Namimoto
Kazunori
K
Harada
Shouzaburou
S
Uemura
Yasuyuki
Y
Yamashita
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods*; D016477:Artifacts; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D005268:Femoral Vein / Q000000981:diagnostic imaging*; D006801:Humans; D007472:Iohexol / Q000008:administration & dosage; D035002:Lower Extremity / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D011152:Popliteal Vein / Q000000981:diagnostic imaging*; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media; D007472:Iohexol