Spondylodiscitis: a call for unified guidelines

Infectious spondylodiscitis is a life-threatening condition whose diagnosis remains challenging due to nonspecific clinical presentation, heterogeneous imaging pathways, and variable microbiologic yield. Although MRI represents the diagnostic reference standard, international guidelines diverge regarding the application, role of contrast, use of whole-spine vs segmental imaging, and indications for complementary modalities such as CT and [¹⁸F]FDG-PET/CT. Similarly, recommendations on image-guided biopsy timing, number and type of samples, and integration of molecular diagnostic techniques remain inconsistent. This variability reflects both methodological differences and the uneven availability of high-quality evidence across specialties. We performed a comparative review of major international guidelines (IDSA, EANM/ESNR/ESCMID, S2k, ACR, SPILF, and EANS) to identify areas of convergence and discordance in the diagnostic approach to spondylodiscitis, with particular focus on imaging algorithms, microbiologic confirmation, and follow-up assessment. While all documents acknowledge MRI as the cornerstone of early detection and emphasize the importance of image-guided biopsy, unresolved issues persist regarding the diagnostic value of whole-spine imaging, optimal pre-biopsy antibiotic washout, standardization of specimen handling, and incorporation of molecular microbiology. Follow-up imaging remains another major gap, with discordance between recommendations and limited evidence to guide interpretation of persistent MRI abnormalities. This analysis highlights the need for unified, multidisciplinary, evidence-based guidelines that integrate radiology, infectious diseases, microbiology, and spine surgery. Future research will evaluate whether harmonizing diagnostic pathways may reduce delays, improve microbiologic yield, and promote more consistent imaging strategies. KEY POINTS: Question Are current guideline recommendations for imaging assessment and follow-up of spondylodiscitis consistent, or do discrepancies limit the definition of an optimal imaging strategy? Findings Major international guidelines show substantial heterogeneity in MRI, CT, and PET/CT indications, biopsy timing, use of molecular diagnostics, and follow-up, underscoring unresolved diagnostic gaps. Clinical relevance This analysis highlights discrepancies among diagnostic recommendations for spondylodiscitis, identifying areas where greater harmonization of imaging and biopsy strategies may potentially reduce variability and improve clarity in clinical decision-making.