Michal Haviva Gabbai MD, Presenter: Nothing to Disclose

Isaac Leichter PhD, Abstract Co-Author: Nothing to Disclose

Zimam Romman, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Amiaz Altman PhD, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Jacob Sosna MD, Abstract Co-Author: Consultant, ActiViews Ltd Research Grant, Koninklijke Philips Electronics NV

In existing tube-based dual-energy CT (DECT), dual-energy protocols must be prescribed in advance to select tube voltage or operate the two tubes at different kV. Spectral detector-based DECT enables retrospective reconstruction and analysis of data obtained from a single CT acquisition with no requirement to plan a dual-energy protocol in advance. The purpose of this study was to assess the potential added value of retrospective dual-energy reconstruction features.

A total of 43 patients were scanned with a novel Spectral Detector CT (SDCT) prototype (Philips Healthcare, Cleveland, OH, USA). IRB approval and patient consent were obtained. The clinical indication for each case was evaluated, and indications were compared to the final diagnosis by two radiologists in consensus. The number of cases in which retrospective analysis of spectral data could potentially assist in the diagnosis while the indication on the request did not suggest in advance the use of dual-energy reconstruction was analyzed.

SDCT data helped to achieve the diagnosis for 19 out of 43 patients (44%). In 8 of the 43 (18.6%), clinical history on the study request indicated potential advantage from use of a dual-energy protocol (4 suspected pulmonary emboli, 2 suspected kidney stones, 1 suspected insulinoma, 1 suspected hepato cellular carcinoma). In the remaining 35 patients, dual-energy reconstruction was not indicated from the referral. In 11 of the 35 patients (31%) retrospective spectral detector reconstruction improved visualization of the following unexpected pathologies: 2 incidental adrenal adenomas (contrast enhanced CT, virtual non-enhanced images), 2 pelvic DVT cases (low KeV images), 3 pancreatic cysts (with low KeV, improved contrast-to-noise), 3 metal implants (reduced artifacts at higher KeV), and one abdominal aortic aneurysm (suboptimal CTA visualized at low KeV).

Retrospective spectral image reconstruction and analysis may frequently offer clinical advantage in cases where DECT is not indicated based on clinical history.

Spectral detector-based dual-layer CT allows retrospective reconstruction and post-processing image analysis that may frequently be useful in clinical practice.

Gabbai, M, Leichter, I, Romman, Z, Altman, A, Sosna, J, The Clinical Impact of Retrospective Analysis in Spectral Detector Dual Energy Body CT.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13018312.html