This study intends to use a prospective, observational, self-controlled, multi-center study design to evaluate the feasibility and diagnostic efficacy of 18F-FDG PET/CT and 18F-FAPI PET/MRI imaging for the evaluation of systemic fibrosis in MF patients based on the results of bone marrow pathological biopsy, and to analyze the relationship between imaging results and clinical prognosis.

Myelofibrosis (MF) is a pathological process characterized by dysplasia of bone marrow fibrous tissue, clonal proliferation of potential stem cells, inflammatory changes in the bone marrow microenvironment, and extramedullary hematopoiesis. Bone marrow histopathology is the gold standard for diagnosis, but because of the invasive nature of the puncture, repeated examination is not possible to dynamically monitor the disease process. In addition, due to the focal nature of puncture biopsy, it can not accurately reflect the systemic disease. 18F-FDG PET/CT provides visual assessment of MF, but its diagnostic effectiveness decreases as MF progresses. 18F-FAPI PET/MRI characterizes fiber activation processes in a variety of diseases. This study intends to use a prospective, observational, self-controlled, multi-center study design to evaluate the feasibility and diagnostic efficacy of 18F-FDG PET/CT and 18F-FAPI PET/MRI imaging for the evaluation of systemic fibrosis in MF patients based on the results of bone marrow pathological biopsy, and to analyze the relationship between imaging results and clinical prognosis.

Inclusion Criteria:

• Patients with primary myelofibrosis or myelofibrosis secondary to myeloid tumors were diagnosed according to the diagnostic criteria of who 2022.
• Stable vital signs, ECOG score ≥ 2 points, tolerate and cooperate to complete 18F-FDG PET/CT and 18F-FAPI PET/MRI examination.
• The interval between imaging ,hematologic, cytogenetic and pathology was < 2 weeks.
• Willing to accept 18F-FDG PET/CT and 18F-FAPI PET/MRI , sign the informed consent.

Exclusion Criteria:

• Inability or unwillingness to provide informed consent.
• Other malignancies, autoimmune diseases, or chronic active infections were diagnosed within 1 year before the diagnosis of myelofibrosis.
• Current infection was present within 1 week before PET examination.
• Pregnant or lactation.
• Unable to follow protocol to complete follow-up.
• Have received glucocorticoid therapy within 2 weeks before PET imaging examination.
• Using granulocyte colony-stimulating factor (G-CSF) within 4 weeks prior to PET imaging.

myelofibrosis