CT volumetric measurements correlate with split renal function in renal trauma

Int Urol Nephrol. 2020 Nov;52(11):2107-2111. doi: 10.1007/s11255-020-02534-7. Epub 2020 Jun 9.

Abstract

Purpose: To evaluate whether volumetric measurements of segmental vascular injuries (SVIs) based on computed tomography (CT) imaging obtained during an initial trauma survey correlate with future nuclear medicine (NM) split renal function.

Methods: A retrospective review was performed of renal trauma patients treated at a level 1 trauma center between 2008 and 2015. Patients with unilateral SVIs on initial CT imaging with follow-up NM renal scans were evaluated. CT-based split renal function was calculated by assessing the ratio of ipsilateral uninjured kidney volume to bilateral total uninjured kidney volume by two separate radiologists.

Results: Eight patients with unilateral SVIs on initial CT trauma evaluation underwent follow-up NM renal scans at a mean of 4 months (range 2-6) after injury. Mean NM split renal function of the injured kidney was 43% (range 22-57). Based on the CT volumetric measurements of the affected kidney, mean percent injured was 23% (range 7-62) with a calculated mean split renal function of 44% (range 23-60). Calculated mean CT split function correlated with NM split function (R = 0.89). Intraclass correlation measuring inter-rater reliability for CT volumetric measurements was 0.94 (95% confidence interval 0.72-0.99).

Conclusion: Volumetric measurements based on CT imaging obtained during the initial trauma evaluation correlated with future NM split renal function after SVIs with high inter-rater reliability. This method utilizes pre-existing imaging and avoids additional radiation exposure, work burden, and financial cost from a NM scan. Further evaluation is required to assess feasibility with more complex injuries.

Keywords: Computed tomography; Function; Kidney; Nuclear medicine; Trauma.