Single center, open-label, phase IV clinical trial to study the application of radiomics in molecular imaging for diagnosis and follow-up of CVDIs. The study will include three populations:

• Retrospective cohort (2018-2025)
• Prospective cohort (2026-2027)
• Control group (prospective)

The study is a single center, open-label, phase IV clinical trial to study the application of radiomics in molecular imaging for diagnosis and follow-up of CVDIs.

The study will be conducted in one Spanish hospital where two hundred patients will be included in the corresponding cohort according to their characteristics (see section "5.1 Description of Study Population"). The study will include three populations:

• Retrospective cohort (2018-2025): patients with a confirmed CVDIs who underwent FDG-PET for diagnosis or follow-up. The retrospective cohort will include patients from 2018 to 2025 who have already undergone FDG-PET imaging and for whom complete clinical, microbiological, and therapeutic data are available.

These data were collected under a previously approved protocol with CEIm (Clinical Research Ethics Committee) authorization: HCB/2015/0769 and HCB/2024/1173.

No new procedures will be performed on retrospective patients; only a re-analysis of existing FDG-PET/CT scans using radiomics techniques will be conducted.

• Prospective cohort (2026-2027): This cohort will include patients with a confirmed CVDI undergoing FDG-PET/CT as part of standard clinical care. Patients will be included before performing any FDG-PET/CT examination, which will be acquired after signing informed consent.

All diagnostic and therapeutic procedures, including antibiotic or SAT when indicated, will follow standard clinical practice and will not be influenced by the study.

Written informed consent will be obtained to authorize the use of their clinical and imaging data for research purposes.

• Control group (prospective): This group will include 40 patients with recently implanted cardiovascular devices and no clinical suspicion of infection, distributed as follows:

• 10 pacemakers,
• 10 valvular prostheses,
• 10 vascular prostheses,
• 10 transcatheter aortic valve implants (TAVIs) Inclusion will occur after device implantation and informed consent signature. FDG-PET/CT imaging will be performed at approximately 1 month and 12 months post-implantation.

Inclusion Criteria:

• Age ≥ 18 years.
• Implanted cardiovascular device (prosthetic valve, TAVI, CIED, vascular graft/endograft).
• For infected cohorts: patients studied by FDG-PET with definitive diagnosis of CVDI based on multidisciplinary evaluation.
• For control group: no clinical suspicion of infection at time of inclusion.
• Written Informed consent provided (prospective cohort and control group).
• Women of child-bearing potential must have a negative pregnancy test in serum or urine before the inclusion in the study and agree to use highly effective contraceptive methods during the study. Highly effective contraceptive methods will include: intrauterine device, bilateral tubal occlusion, vasectomized partner and sexual abstinence (only if refraining from heterosexual intercourse during the period of twelve months of duration of the study).

Exclusion Criteria:

• Inability to undergo FDG-PET due to contraindications (e.g., allergies, claustrophobia).
• Pregnancy or breastfeeding.
• Incomplete clinical data or lack of access to imaging studies.
• Refusal or withdrawal of informed consent (for control and prospective cohort).