This study is a prospective cohort investigation in which consecutive eligible patients undergo 18F-FAPI PET/MR imaging. Chronic kidney disease (CKD) participants are stratified into two groups:Group I ：CKD stages 1-3（eGFR ≥ 30 mL/min/1.73 m²）,Group II :CKD stages 4-5(eGFR < 30 mL/min/1.73 m²).

Using 18F-FAPI PET/MR, we will evaluate global cardiac functional impairment and myocardial fibrosis characteristics, and analyze their associations with the degree of renal dysfunction.

Inclusion Criteria:

1. Age between 18 and 80 years, regardless of sex.
2. Clinically diagnosed with chronic kidney disease (CKD), based on KDIGO guidelines.
3. Complete clinical data available.
4. Written informed consent for participation and for undergoing 18F-FAPI PET/MR imaging is obtained from the patient or their legal guardian.
5. Female participants must agree to use effective contraception during the study and for at least 6 months after its completion (e.g., sterilization, intrauterine hormonal devices, condoms, hormonal contraceptives, abstinence, or vasectomized partner). Male participants must also agree to use contraception during the study and for 6 months after its completion.

Exclusion Criteria:

1. Women who are planning to conceive, currently pregnant, or breastfeeding.
2. Contraindications to PET/MR imaging, including but not limited to metal implants, claustrophobia, or inability to tolerate cardiac MRI due to respiratory difficulties.
3. History of allergy or hypersensitivity to gadolinium-based contrast agents.
4. Presence of malignant tumors or other serious progressive diseases.
5. Patients with severe cardiac conditions, such as advanced heart failure, severe valvular disease, or cardiomyopathies.
6. Hemodynamic instability.
7. Presence of severe systemic or localized infections, or other serious comorbid conditions.
8. Incomplete clinical data.
9. Any other reason deemed by the investigators to make the subject unsuitable for participation, including inability or unwillingness to comply with study procedures and requirements.
10. Determined by the investigators to be inappropriate for inclusion in the study.

Patients aged 18 to 80 years with clinically diagnosed chronic kidney disease (CKD), classified according to the KDIGO guidelines. Participants will be stratified into two groups based on renal function: Group I (CKD stages 1-3, eGFR ≥ 30 mL/min/1.73 m²) and Group II (CKD stages 4-5, eGFR < 30 mL/min/1.73 m²). Subjects will be consecutively recruited from the Department of Nephrology and Cardiology of The Affiliated Hospital of Qingdao University. Both male and female patients will be included.