Juliane Schelhorn MD, Presenter: Nothing to Disclose

Marcus Paul Reinboldt, Abstract Co-Author: Nothing to Disclose

Guido Gerken, Abstract Co-Author: Nothing to Disclose

Thomas C. Lauenstein MD, Abstract Co-Author: Nothing to Disclose

Sonja Kinner MD, Abstract Co-Author: Nothing to Disclose

Selective internal radiation therapy (SIRT) with Yttrium-90 (Y90) microspheres is a promising therapy option in patients with advanced hepatocellular carcinoma (HCC). Early detection of therapy response is warranted to ensure adequate ongoing treatment, but size measurements and contrast enhancement are often not conclusive. We aimed to evaluate diffusion weighted imaging (DWI) for early prediction of tumor response in patients with HCC following SIRT.

42 patients (33 male, 9 female, mean age 61.2 years) with histopathologically proven HCC underwent magnetic resonance imaging (MRI) including DWI before and 30 days (early) and 180 days (late) after Y90 therapy. Morphologic HCC size and apparent diffusion coefficients (ADC) were compared for at all three time points and were correlated with clinical and laboratory parameters to assess response.

SIRT could be successfully performed in all 42 patients (one injection n=25, two injections n=17). Mean tumor size at baseline amounted to 6.7cm; mean baseline ADC amounted to 1.55 x 10-3 mm2/s. After 30 days tumor size did not show any difference (mean tumor size d30= 6.5cm) in responders and non-responders while ADC values increased to 1.64 x 10-3 mm2/s (p=0.34) in responders and stayed constant in non-responders. After 180 days, tumor size showed a slight decrease (mean tumor size d180= 6.1cm) in responders and a slight increase in non-responders while ADC values turned out to be significantly higher compared to pretherapeutic imaging (1.82 x 10-3 mm2/s; p<0.01) in the responder group.

Response to SIRT can be documented by DWI in most patients after 30 days and more pronounced after 180 days. However, vital tumor size changed only little in early and late control MRI. Tumor size therefore cannot be used as response indicator.

DWI is an important tool to assess response or non-response to SIRT in patients with HCC and should be used as imaging modality of choice to evaluate therapy response.

Schelhorn, J, Reinboldt, M, Gerken, G, Lauenstein, T, Kinner, S, DWI Can Predict Early Therapy Response in Patients with Hepatocellular Carcinoma after Selective Internal Radiation Therapy (SIRT).  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14011079.html