Atul Padole MD, Presenter: Nothing to Disclose

Garry Choy MD, MS, Abstract Co-Author: Nothing to Disclose

Diego Alfonso Lira MD, Abstract Co-Author: Nothing to Disclose

Ranish Deedar Ali Khawaja MD, Abstract Co-Author: Nothing to Disclose

Sarabjeet Singh MD, Abstract Co-Author: Research Grant, Siemens AG Research Grant, Toshiba Corporation Research Grant, General Electric Company Research Grant, Koninklijke Philips NV

Mannudeep K. S. Kalra MD, Abstract Co-Author: Nothing to Disclose

Alexi Otrakji MD, Abstract Co-Author: Nothing to Disclose

Roberto Lo Gullo MD, Abstract Co-Author: Nothing to Disclose

Sarvenaz Pourjabbar MD, Abstract Co-Author: Nothing to Disclose

Subba Rao Digumarthy MD, Abstract Co-Author: Nothing to Disclose

Victorine Vining Muse MD, Abstract Co-Author: Nothing to Disclose

To evaluate low dose abdominal CT images reconstructed with imaged based (SafeCT), adaptive statistical (ASIR), and model based (MBIR) iterative reconstruction techniques to the standard dose abdomen CT.  

In an IRB approved, prospective clinical study included 21 patients (mean age 68 ± 7 years, mean weight 82±15 kg, M:F 14:7, undergoing routine abdomen CT on a 64 channel MDCT (Discovery CT750 HD). After standard of care abdominal CT, low dose images were acquired at 120 kV and reduced mAs (CTDIvol of 2.5 mGy). Sinogram data of low dose series were reconstructed with SafeCT (AP0, AP1), ASIR (SS70, SS90 GE Healthcare) and MBIR(GE Healthcare) and standard dose abdomen CT reconstructed with ASIR (SS50) (n= 6*21=210 series). Two radiologists performed independent and blinded comparison for lesion detection, lesion conspicuity, and visibility of small structures, first for all patients with low dose images and subsequently for standard dose images.

Mean CTDIvol were 13 ± 1.7 and 2.5 ± 0.1 mGy for standard and low dose abdominal CT, respectively. There were two missed lesions (small liver cyst and kidney cyst) on low dose images. Pancreatic ducts could be seen in only 5/10 patients at low dose regardless of iterative reconstruction techniques. The lesion conspicuity (23/25 lesions) was sufficient for clinical diagnostic performance for low dose SafeCT, ASIR and MBIR images. Low dose MBIR had limited diagnostic performance for evaluation of liver and kidney parenchyma in 18/21 patients compared to 8/21 for SafeCT and 7/21 for ASIR images. The liver margin, adrenal glands, pancreatic contour, gall bladder, peritoneum, retroperitoneum, and bowels were sufficient and equally seen on all low dose images regardless of iterative reconstruction techniques.

Low dose abdominal CT at 2.5 mGy is sufficient for most clinically significant lesions with SafeCT, ASIR, and MBIR. However, evaluation of pancreas requires higher dose than 2.5 mGy. Visibility of normal liver parenchyma is limited on low dose MBIR images.

Iterative reconstruction techniques can allow sufficient clinical diagnostic performance for routine abdominal CT image at CTDIvol of 2.5 mGy.

Padole, A, Choy, G, Lira, D, Khawaja, R, Singh, S, Kalra, M, Otrakji, A, Lo Gullo, R, Pourjabbar, S, Digumarthy, S, Muse, V, Comparison of Image Based, Adaptive Statistical, and Model Based Iterative Reconstruction Techniques for Substantial Dose Reduction for Abdominal CT.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14008186.html