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Pure Iterative Reconstruction Improves Image Quality in Computed Tomography of the Abdomen and Pelvis Acquired at Substantially Reduced Radiation Doses in Patients With Active Crohn Disease

McLaughlin, Patrick D. MD; Murphy, Kevin P. MD; Twomey, Maria MD; O'Neill, Siobhan B. MD; Moloney, Fiachra MD; O'Connor, Owen J. MD; O'Regan, Kevin MD; McSweeney, Sean MD; McGarrigle, Anne Marie PhD; Moore, Niamh; Bye, Jackie; Shanahan, Fergus MD; Maher, Michael M. MD

Journal of Computer Assisted Tomography: March/April 2016 - Volume 40 - Issue 2 - p 225–233
doi: 10.1097/RCT.0000000000000358
Abdominal and Pelvic Imaging

We assessed diagnostic accuracy and image quality of modified protocol (MP) computed tomography (CT) of the abdomen and pelvis reconstructed using pure iterative reconstruction (IR) in patients with Crohn disease (CD).

Methods Thirty-four consecutive patients with CD were referred with suspected extramural complications. Two contemporaneous CT datasets were acquired in all patients: standard protocol (SP) and MP. The MP and SP protocols were designed to impart radiation exposures of 10% to 20% and 80% to 90% of routine abdominopelvic CT, respectively. The MP images were reconstructed with model-based IR (MBIR) and adaptive statistical IR (ASIR).

Results The MP-CT and SP-CT dose length product were 88 (58) (1.27 [0.87] mSv) and 303 [204] (4.8 [2.99] mSv), respectively (P < 0.001). Median diagnostic acceptability, spatial resolution, and contrast resolution were significantly higher and subjective noise scores were significantly lower on SP-ASIR 40 compared with all MP datasets. There was perfect clinical agreement between MP-MBIR and SP-ASIR 40 images for detection of extramural complications.

Conclusions Modified protocol CT using pure IR is feasible for assessment of active CD.

From the *Department of Radiology, Cork University Hospital, Wilton, Cork; †Department of Radiology, University College Cork, Cork, Ireland; ‡GE Healthcare – Technologies, Hertfordshire, United Kingdom; and §Department of Medicine, University College Cork, Cork, Ireland.

Received for publication September 2, 2015; accepted October 21, 2015.

Correspondence to: Fiachra Moloney, MD, Department of Radiology, Cork University Hospital, 1 Bishopstown Road, Wilton, Cork, Ireland (e-mail:

The authors declare no conflict of interest.

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