title: Cerebral computed tomography angiography using a low tube voltage (80 kVp) and a moderate concentration of iodine contrast material: a quantitative and qualitative comparison with conventional computed tomography angiography.
abstract: OBJECTIVE
  To investigate the feasibility of an 80-kVp protocol using a moderate concentration contrast material (MC-CM) for cerebral computed tomography angiography by comparison with a conventional 120-kVp protocol using a high concentration contrast material (HC-CM).
  
  
  METHODS
  Attenuation values and signal-to-noise ratios (SNRs) were determined in a head phantom for 2 tube voltages (80 and 120 kVp) and 2 different iodine concentration contrast materials (HC-CM and MC-CM). Among 90 consecutive patients, 45 patients were scanned with 120 kVp and 150 mAs(eff) after administration of 70 mL of HC-CM (370 mg iodine [mgI]/mL), whereas the other 45 patients were scanned with 80 kVp and 370 mAs(eff) after administration of 70 mL of MC-CM (300 mgI/mL). The Hounsfield units (HU) of the internal carotid artery T junction, SNR, contrast-to-noise ratio (CNR), subjective degree of arterial enhancement, image noise, sharpness of the cerebral arterial boundary, and overall diagnostic image quality were compared between the 2 groups.
  
  
  RESULTS
  The mean attenuation of the internal carotid artery T junction, SNR, and CNR was significantly higher in the 80 kVp with MC-CM group (379.2, 33.7, and 31.1 HU, respectively) than in the 120 kVp with HC-CM group (282.2, 31.1, and 27.2 HU, respectively). The 80-kVp protocol resulted in significantly higher score in arterial enhancement, sharpness of the cerebral arteries, and overall diagnostic image quality. The effective dose of 80 kVp (0.7 mSv) was 22.2% lower than that of 120 kVp (0.9 mSv).
  
  
  CONCLUSIONS
  The use of 80 kVp with MC-CM improved arterial enhancement, SNR, and CNR and provided superior quality images using a smaller amount of iodine and a lower radiation dose than the conventional protocol of 120 kVp with HC-CM.
authors: Department of Radiology, Yonsei University College of Medicine, Gangnam Severance Hospital, Gangnam-gu, Seoul, Korea.
authors: Eun-Suk
authors: ES
authors: Cho
authors: Tae-Sub
authors: TS
authors: Chung
authors: Dae Kun
authors: DK
authors: Oh
authors: Hyun Seok
authors: HS
authors: Choi
authors: Sang Hyun
authors: SH
authors: Suh
authors: Hyeon-Kyeong
authors: HK
authors: Lee
authors: Kyung Hee
authors: KH
authors: Lee
mesh_terms: D000328:Adult; D001822:Body Burden; D002533:Cerebral Angiography / Q000379:methods*; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008875:Middle Aged; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*