Abstract
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Objectives To determine if qualitative indicators using novel SPECT/CT imaging approaches can guide patient selection during initial evaluation and subsequent treatment with Yttrium-90 radioembolization (RE).
Methods 22 patients with unresectable hepatic malignancies or metastases who underwent pre-RE MAA SPECT/CT and post-RE bremsstrahlung SPECT/CT imaging following 90Y RE were retrospectively evaluated. 2 experienced readers evaluated 22 target tumor lesions and designated each as homogeneous, heterogeneous or absent based on visual assessment of intratumoral MAA and 90Y activity distribution. Patterns of uptake were correlated with outcomes.
Results Of 22 target tumor lesions, 5, 13 and 4 lesions demonstrated homogeneous, heterogeneous and absent MAA activity distribution, respectively. Furthermore, 5/5, 11/13 and 4/4 lesions maintained the same visual distribution with 90Y bremsstrahlung imaging after RE. Using the criteria that (1) absent activity on pre-RE MAA scans would result in disease progression despite RE and (2) homogeneous or heterogeneous MAA activity would result in non-progression following RE, the sensitivity and specificity for predicting response using intratumoral MAA activity distribution in target lesions was 50% in all patients (67% for those patients with colorectal metastases) and 100%, respectively.
Conclusions Visual patterns of intratumoral activity noted on pre-RE MAA SPECT/CT imaging for individual patients may be a useful predictor of response to RE therapy in addition to assessing activity in non-target tissues. This information may be useful to physicians evaluating patients for RE therapy.