E4635. Visual Voyage: Mapping Ankylosing Spondylitis with Imaging
  1. Mili Rohilla; Saint Vincent Hospital
  2. Samruddhi Jain; Saint Vincent Hospital
  3. Suman Biswas; University of Rochester
  4. Joshua Russell; Saint Vincent Hospital
Accurate diagnosis of ankylosing spondylitis (AS), a chronic inflammatory seronegative spondyloarthropathy, relies heavily on imaging. Clinical symptoms of low back pain with or without stiffness for over 3 months under the age 45 are a typical presentation with a high disease predilection in men. The Assessment of SpondyloArthritis International Society (ASAS) classification criteria considers clinical, laboratory, and imaging factors to assess patients for AS. Radiography and MRI are instrumental in confirming sacroiliitis, and CT scans aid in surgical management decisions. This exhibit delves into the crucial role of imaging in deciphering AS and its clinical significance.

Educational Goals / Teaching Points
This exhibit aims to equip healthcare professionals with a deep understanding of imaging's role in diagnosing and assessing AS. It delves into the disease's underlying pathology, classification criteria nuances, modality-based imaging specifics, and implications for clinical practice.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
AS manifests primarily as axial inflammation, with genetic and immunological factors, notably HLA-B27, contributing to its etiology. Modality-specific imaging findings. A. Radiography: demonstrates sacroiliitis and spinal changes; early stages display erosions and sclerosis, and advanced AS exhibits syndesmophytes, leading to the "bamboo spine" appearance. Sacroiliitis grading (grading 0–IV) can be achieved using plain radiographs with modified New York Criteria. B. CT: demonstrates precise bony details, particularly for spinal evaluation; highlights syndesmophytes and erosions crucial for surgical planning as opposed to conservative management. C. MRI: highly sensitive to inflammation; active sacroiliitis presents as bone marrow edema, synovitis, and enthesitis. Spinal inflammation is evident in increased short inversion time inversion recovery (STIR) sequence signal.

Imaging is crucial for managing AS. Radiography, MRI, and CT aid in early diagnosis, disease activity monitoring, and structural damage assessment. Integrating clinical, lab, and imaging data are essential for improving patient outcomes.