PET/MRI of Hepatic 90Y Microsphere Deposition Determines Individual Tumor Response.

PET/MRI of Hepatic 90Y Microsphere Deposition Determines Individual Tumor Response.

Cardiovasc Intervent Radiol. 2015 Dec 31;

Authors: Fowler KJ, Maughan NM, Laforest R, Saad NE, Sharma A, Olsen J, Speirs CK, Parikh PJ

Abstract
PURPOSE: The purpose of our study is to determine if there is a relationship between dose deposition measured by PET/MRI and individual lesion response to yttrium-90 ((90)Y) microsphere radioembolization.
MATERIALS AND METHODS: 26 patients undergoing lobar treatment with (90)Y microspheres underwent PET/MRI within 66 h of treatment and had follow-up imaging available. Adequate visualization of tumor was available in 24 patients, and contours were drawn on simultaneously acquired PET/MRI data. Dose volume histograms (DVHs) were extracted from dose maps, which were generated using a voxelized dose kernel. Similar contours to capture dimensional and volumetric change of tumors were drawn on follow-up imaging. Response was analyzed using both RECIST and volumetric RECIST (vRECIST) criteria.
RESULTS: A total of 8 hepatocellular carcinoma (HCC), 4 neuroendocrine tumor (NET), 9 colorectal metastases (CRC) patients, and 3 patients with other metastatic disease met inclusion criteria. Average dose was useful in predicting response between responders and non-responders for all lesion types and for CRC lesions alone using both response criteria (p < 0.05). D70 (minimum dose to 70 % of volume) was also useful in predicting response when using vRECIST. No significant trend was seen in the other tumor types. For CRC lesions, an average dose of 29.8 Gy offered 76.9 % sensitivity and 75.9 % specificity for response.
CONCLUSIONS: PET/MRI of (90)Y microsphere distribution showed significantly higher DVH values for responders than non-responders in patients with CRC. DVH analysis of (90)Y microsphere distribution following treatment may be an important predictor of response and could be used to guide future adaptive therapy trials.

PMID: 26721589 [PubMed - as supplied by publisher]

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