Читать книгу Leksell Radiosurgery - Группа авторов - Страница 59

Physiologic MRI and metabolic PET imaging can add to information obtained by morphological imaging and highlight specific biologic processes. These imaging techniques permit the in vivo analysis of tumor tissue properties including chemical composition, tumor vasculature, perfusion, and tumor cellularity [6]. In cases of recurrent tumors (glial or metastatic) assessment of tumor response after SRS can be challenging due to non-specific imaging changes that can represent either tumor progression or an adverse radiation effect. Underlying processes of radiation effects can cause a temporary increase in contrast enhancement on MRI, making the differentiation between true progression and radiation effects extremely difficult. Mechanisms that may contribute to radiation-induced imaging changes include vascular injury, glial and white matter changes, and immunological mechanisms. Physiologic imaging can be useful in selected cases in determining tumor growth versus adverse radiation effect.