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.
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.
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).
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).
From the *Diagnostic Radiology, Amakusa Medical Center, Amakusa, Japan; †Department of Diagnostic Radiology, Graduate School of Medical, Kumamoto University, Kumamoto, Japan; Departments of ‡Surgery, and §Neurosurgery, Amakusa Medical Center, Amakusa, Japan.
Received for publication April 19, 2010; accepted July 30, 2010.
Reprints: Takeshi Nakaura, MD, Amakusa Medical Center, Kameba 854-1, Amakusa, Kumamoto 863-0046, Japan (e-mail: email@example.com).
The authors do not have conflict of interest.
The authors did not receive funding for this work.