title: Computed tomographic venography for varicose veins of the lower extremities: prospective comparison of 80-kVp and conventional 120-kVp protocols.
abstract: OBJECTIVE
  To prospectively investigate the feasibility of an 80-kilovolt (peak) (kVp) protocol in computed tomographic venography for varicose veins of the lower extremities by comparison with conventional 120-kVp protocol.
  
  
  METHODS
  Attenuation values and signal-to-noise ratio of iodine contrast medium (CM) were determined in a water phantom for 2 tube voltages (80 kVp and 120 kVp). Among 100 patients, 50 patients were scanned with 120 kVp and 150 effective milliampere second (mAs(eff)), and the other 50 patients were scanned with 80 kVp and 390 mAs(eff) after the administration of 1.7-mL/kg CM (370 mg of iodine per milliliter). The 2 groups were compared for venous attenuation, contrast-to-noise ratio, and subjective degree of venous enhancement, image noise, and overall diagnostic image quality.
  
  
  RESULTS
  In the phantom, the attenuation value and signal-to-noise ratio value for iodine CM at 80 kVp were 63.8% and 33.0% higher, respectively, than those obtained at 120 kVp. The mean attenuation of the measured veins of the lower extremities was 148.3 Hounsfield units (HU) for the 80-kVp protocol and 94.8 HU for the 120-kVp protocol. Contrast-to-noise ratio was also significantly higher with the 80-kVp protocol. The overall diagnostic image quality of the 3-dimensional volume-rendered images was good with both protocols. The subjective score for venous enhancement was higher at the 80-kVp protocol. The mean volume computed tomography dose index of the 80-kVp (5.6 mGy) protocol was 23.3% lower than that of the 120-kVp (7.3 mGy) protocol.
  
  
  CONCLUSIONS
  The use of the 80-kVp protocol improved overall venous attenuation, especially in perforating vein, and provided similarly high diagnostic image quality with a lower radiation dose when compared to the conventional 120-kVp protocol.
authors.affiliation: Department of Radiology, Yonsei University College of Medicine, Gangnam Severance Hospital, Seoul, Korea.
authors.forename: Eun-Suk
authors.initials: ES
authors.lastname: Cho
authors.forename: Joo Hee
authors.initials: JH
authors.lastname: Kim
authors.forename: Sungjun
authors.initials: S
authors.lastname: Kim
authors.forename: Jeong-Sik
authors.initials: JS
authors.lastname: Yu
authors.forename: Jae-Joon
authors.initials: JJ
authors.lastname: Chung
authors.forename: Choon-Sik
authors.initials: CS
authors.lastname: Yoon
authors.forename: Hyeon-Kyeong
authors.initials: HK
authors.lastname: Lee
authors.forename: Kyung Hee
authors.initials: KH
authors.lastname: Lee
mesh_terms: D000328:Adult; D003287:Contrast Media; D005240:Feasibility Studies; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D035002:Lower Extremity / Q000098:blood supply* / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D016491:Peripheral Vascular Diseases / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D010690:Phlebography / Q000379:methods*; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide