Michael Peter Wissmeyer MD, Presenter: Nothing to Disclose

Valentina Garibotto, Abstract Co-Author: Nothing to Disclose

Pietro Mjano MD, Abstract Co-Author: Nothing to Disclose

Romain Breguet MD, Abstract Co-Author: Nothing to Disclose

Christoph D. Becker MD, Abstract Co-Author: Nothing to Disclose

Osman Ratib MD, PhD, Abstract Co-Author: Research Consultant, Koninklijke Philips Electronics NV

Sylvain Terraz MD, Abstract Co-Author: Nothing to Disclose

To quantify treated volumes and compare them with morphologic and functional target volume estimation algorithms in patients undergoing SIRT.

We evaluated 28 consecutive patients scheduled for SIRT due to hepatocellular carcinoma or liver metastases from other tumors into this pilot study. Treated liver volumes were calculated using a threshold based semi-automatic delineation technique on post-interventional Y-90 SPECT-CT. The pre-interventional target volumes and Y-90 activities were estimated by manual delineation on contrast enhanced CT and on pre-therapeutic Tc-99m-MAA SPECT-CT by two experienced observers. Additionally, the expected lung dose was determined on the base of the lung shunt fraction as derived from planar whole-body MAA-images. Treated and target volumes, Y-90 activities and lung doses were compared using correlation coefficients (cc) and a paired two sided t-test.

7 patients were excluded because of too high hepato-pulmonary shunt fractions. In 7 other patients with bilobar treatment, functional target volumes could not be drawn on the MAA-SPECT/CT due to technical reasons. In the remaining 14 patients, estimated mean±SD treated liver volume was 1247±533ml using a threshold of 24.2±9.1% of maximum counts for semi-automatic volume estimation. Absolute counts were not useful for threshold selection. Estimated target volumes (ml), calculated Y-90 activities (GBq), and lung doses (Gy) were 1344±524, 3.62±1.37, and 13.03±8.35 for CT, compared to 1352±664, 3.62±1.69, and 12.35±7.54 for MAA-SPECT-CT. Overall, morphologic (cc=0.88; p= 0.185) and functional (cc=0.92; p=0.177) target volumes correlated well with treated volumes, with a slight but not statistically significant advantage for the functional approach (p=0.125).

Treated liver volumes can be quantified easily on the post-interventional Y-90 SPECT-CT using a threshold based semi-automatic approach. Functional and morphologic pre-therapeutic target volume estimation correlates well with the treated volumes, with a slight advantage of the functional technique, most probably due to patients presenting with perfusion patterns differing from the expected vascular anatomy.

Functional target volume estimation correlates slightly better with treated liver volumes in SIRT than the morphologic apprach and is an important adjunct to depict unexpected liver perfusion patterns

Wissmeyer, M, Garibotto, V, Mjano, P, Breguet, R, Becker, C, Ratib, O, Terraz, S, Quantification of Treated Volumes and Correlation with Functional and Morphologic Target Volume Estimation in SIRT of the Liver.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13019570.html