Jeremy Robert Wortman MD, Presenter: Nothing to Disclose

Urvi Pravin Fulwadhva MD, Abstract Co-Author: Nothing to Disclose

Jeffrey Y. Shyu MD, Abstract Co-Author: Nothing to Disclose

Aaron D. Sodickson MD, PhD, Abstract Co-Author: Research Grant, Siemens AG

To quantify the incidence of indeterminate renal lesions during routine dual energy CT (DECT) in an Emergency Department (ED) setting, and to assess the potential of DECT post-processing to characterize lesions and eliminate the need for further follow-up evaluation.

1400 consecutive contrast enhanced abdominal CT scans were included in the study cohort, obtained in the ED using a DE CT protocol (Siemens SOMATOM Definition Flash). All scans were reviewed by a radiologist to assess for the presence of an indeterminate renal lesion defined for potentially solid lesions as size > 5 mm, attenuation > 20 HU, and lack of macroscopic fat, or for a cystic lesion as presence of thick septations or calcifications, thickened wall, or mural nodules. DE post-processing was performed on all lesions, which were were considered enhancing if there was greater than 15 HU from iodine in contained DE regions of interest. All lesions were subsequently re-classified as benign or indeterminate.

At least one indeterminate renal lesion was identified in 57 (4.1%) patients, with mean lesion size of 1.7 cm. 36/57 (63%) were classified as benign (non-enhancing) after review of the iodine overlay images (36/36 Bosniak II cysts). The remaining 21 lesions (37%) could not be classified as benign (14 enhancing masses; 12/14 < 20 mm, 2/14 > 20 mm; 6 Bosniak IIF cysts, 1 Bosniak III cyst). Of the 57 indeterminate lesions, 9 had correlative imaging obtained with MR, CT, or US, with concordant results in all cases (1 enhancing mass, 8 Bosniak II/IIF cysts).

4.1% of ED patients undergoing abdominal CT had an incidentally detected indeterminate renal lesion. DE CT exonerated 63% of these lesions as benign, potentially averting the need for further workup in 2.6% of ER patients imaged by abdominal CT.

If performed routinely, dual energy CT has the potential to substantially reduce the need for follow-up imaging to further characterize indeterminate renal lesions incidentally detected on Emergency Department abdominal CT scans. 

Wortman, J, Fulwadhva, U, Shyu, J, Sodickson, A, Dual Energy Post-processing of Incidental Renal Lesions Encountered in the Emergency Department: Reducing the Need for Follow-up Imaging.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14005203.html