title: CT enterography at 100 kVp with iterative reconstruction compared to 120 kVp filtered back projection: evaluation of image quality and radiation dose in the same patients.
abstract: OBJECTIVE
  To perform qualitative and quantitative comparison of images in same patients undergoing CT enterography (CTE) with 100 kVp iterative reconstruction and 120 kVp filtered back projection.
  
  
  METHODS
  In this retrospective study, 50 consecutive patients who underwent imaging with 100 kVp and iterative reconstruction (100-IR) and had prior imaging with 120 kVp filtered back projection (120-FBP) were included. Subjective image quality parameters were evaluated by two independent and blinded readers, with higher score implying better image quality. We developed a quantitative measure of image sharpness by measuring edge-width of the psoas-fat interface. Image noise was measured as a standard deviation of attenuation measurement in the homogeneous region of the subcutaneous fat. Image sharpness and noise were measured and compared between 100-IR and 120-FBP acquisitions.
  
  
  RESULTS
  There was approximately 33% lower radiation dose as estimated by CTDIvol with 100-IR compared to 120-FBP (9.95 vs. 15.0; p < 0.0001). There were no significant differences in overall image quality, bowel wall sharpness, and subjective assessment of noise and artifact between 100-IR and 120-FBP for both readers. Mesenteric vessel clarity score was significantly higher with 100-IR for 1 reader (4.34 vs. 4.04; p = 0.008), but not for the second reader. There was higher image sharpness (1.62 vs. 1.89; p < 0.0001) and higher image noise (14.4 vs. 13.2; p = 0.020) with 100-IR compared to 120-FBP acquisition.
  
  
  CONCLUSIONS
  CTE performed at 100 kVp with iterative reconstruction demonstrates dose reduction without significant impact on various measures of image quality when compared to conventional 120 kVp FBP.
authors.affiliation: Department of Radiology, New York University Langone Medical Center, 660 First Avenue, New York, NY, 10016, USA.
authors.forename: Evan
authors.initials: E
authors.lastname: Johnson
authors.forename: Alec J
authors.initials: AJ
authors.lastname: Megibow
authors.forename: Natasha E
authors.initials: NE
authors.lastname: Wehrli
authors.forename: Thomas
authors.initials: T
authors.lastname: O'Donnell
authors.forename: Hersh
authors.initials: H
authors.lastname: Chandarana
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D005260:Female; D006801:Humans; D007410:Intestinal Diseases / Q000000981:diagnostic imaging*; D007421:Intestine, Small / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult