Alexandra Barabasch MD, Presenter: Nothing to Disclose

Nils Andreas Kraemer, Abstract Co-Author: Nothing to Disclose

Alexander Ciritsis, Abstract Co-Author: Nothing to Disclose

Nienke Lynn Hansen MD, Abstract Co-Author: Nothing to Disclose

Philipp Bruners MD, Abstract Co-Author: Nothing to Disclose

Christiane Katharina Kuhl MD, Abstract Co-Author: Nothing to Disclose

We report on the first results of an ongoing study that aims at comparing the accuracy of liver DW-MRI to PET/CT for early response-assessment after trans-arterial Y90-radioembolisation (Y90-RE).

Between June-2010 and December-2013, 145 Y90-RE in 85 patients were performed. Patients who (1) had liver-metastases from solid cancers, and (2) had at least 3 measurable target-lesions in the right liver lobe were included. 25 patients (16 colorectal, 8 breast and 1 CUP) met the inclusion criteria and underwent PET/CT and DW-MRI of the liver within 6 weeks before and within 4-8 weeks after Y90-RE. An increase in mininmal ADC (ADCmin) and a decrease in maximal SUV (SUVmax), respectively, of at least 30% after Y90-RE was regarded as positive response. In diverging response classifications, the final outcome of the patient was used to distinguish true from false response-classifications.

Two patients (2/25, 8 %) were FDG-negative on pre-therapeutic PET, leaving 23 for DWI/PET-correlation. After Y90-RE, overall SUVmax decreased from 7.90 ± 2.75 to 5.47 ± 2.06 (p<0.0001). Minimal ADC (ADCmin) increased from 0.53 ± 0.14 *10-3 mm2/s to 0.73 ± 0.29 *10-3 mm2/s (p=0.0035). A strong inverse correlation was observed for post-therapeutic ADCmin and SUVmax (r=-0.73). Concordant response-classification was observed in 19/23 patients (83 %), discordant in 4/23 (17 %). In 3/4, response based on DWI was confirmed by follow-up. PPV to predict presence of response was 14/15 (93 %) for MRI and 11/10 (91 %) for PET. NPV to predict absence was 10/10 (100 %) for MRI and 10/14 (71 %) for PET. The sensitivity for detecting response was significantly higher for MRI (100 %; 14/14) than for PET (71%; 10/14) (p<0.004).

DW-MRI appears to be significantly more sensitive than PET/CT for demonstrating early response after Y90-RE in patients with secondary liver tumors.

DW-MRI should be preferred for early response assessment after Y90-RE, since it appears to be significantly more sensitive compared to PET/CT.

Barabasch, A, Kraemer, N, Ciritsis, A, Hansen, N, Bruners, P, Kuhl, C, DW-MRI vs. PET/CT for Assessment of Early Treatment Response of Liver Metastases to Y90-Radioembolisation: First Results.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14010438.html