title: Prospective evaluation of prior image constrained compressed sensing (PICCS) algorithm in abdominal CT: a comparison of reduced dose with standard dose imaging.
abstract: OBJECTIVE
  To prospectively study CT dose reduction using the "prior image constrained compressed sensing" (PICCS) reconstruction technique.
  
  
  METHODS
  Immediately following routine standard dose (SD) abdominal MDCT, 50 patients (mean age, 57.7 years; mean BMI, 28.8) underwent a second reduced dose (RD) scan (targeted dose reduction, 70%-90%). DLP, CTDIvol, and SSDE were compared. Several reconstruction algorithms (FBP, ASIR, and PICCS) were applied to the RD series. SD images with FBP served as reference standard. Two blinded readers evaluated each series for subjective image quality and focal lesion detection.
  
  
  RESULTS
  Mean DLP, CTDIvol, and SSDE for RD series were 140.3 mGy cm (median 79.4), 3.7 mGy (median 1.8), and 4.2 mGy (median 2.3) compared with 493.7 mGy cm (median 345.8), 12.9 mGy (median 7.9 mGy), and 14.6 mGy (median 10.1) for SD series, respectively. Mean effective patient diameter was 30.1 cm (median 30), which translates to a mean SSDE reduction of 72% (P < 0.001). RD-PICCS image quality score was 2.8 ± 0.5, improved over the RD-FBP (1.7 ± 0.7) and RD-ASIR (1.9 ± 0.8) (P < 0.001), but lower than SD (3.5 ± 0.5) (P < 0.001). Readers detected 81% (184/228) of focal lesions on RD-PICCS series, vs. 67% (153/228) and 65% (149/228) for RD-FBP and RD-ASIR, respectively. Mean image noise was significantly reduced on RD-PICCS series (13.9 HU) compared with RD-FBP (57.2) and RD-ASIR (44.1) (P < 0.001).
  
  
  CONCLUSIONS
  PICCS allows for marked dose reduction at abdominal CT with improved image quality and diagnostic performance over reduced dose FBP and ASIR. Further study is needed to determine indication-specific dose reduction levels that preserve acceptable diagnostic accuracy relative to higher dose protocols.
authors.affiliation: Department of Radiology, University of Wisconsin School of Medicine and Public Health, E3/311 Clinical Sciences Center, 600 Highland Ave, Madison, WI, 53792-3252, USA, mlubner@uwhealth.org.
authors.forename: Meghan G
authors.initials: MG
authors.lastname: Lubner
authors.forename: Perry J
authors.initials: PJ
authors.lastname: Pickhardt
authors.forename: David H
authors.initials: DH
authors.lastname: Kim
authors.forename: Jie
authors.initials: J
authors.lastname: Tang
authors.forename: Alejandro Munoz
authors.initials: AM
authors.lastname: del Rio
authors.forename: Guang-Hong
authors.initials: GH
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D011860:Radiography, Abdominal / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*