Sacroiliac joint protocol (MRI)

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• MRI sacroiliac joint protocol
• MRI protocol: sacroiliac joints

The MRI sacroiliac joint protocol encompasses a set of MRI sequences for the routine assessment of sacroiliac joints.

Note: This article aims to frame a general concept of an MRI protocol for the assessment of the sacroiliac joint. Protocol specifics will vary depending on MRI scanner type, specific hardware and software, radiologist and perhaps referrer preference, patient factors e.g. implants, specific indications and time constraints.

On this page:

• Indications
• 1.5 vs 3 tesla
• Patient positioning
• Technical parameters
• Sequences
• Related articles
• References

Indications

The classical indication is suspected sacroiliitis. The protocol can be adjusted for the assessment of sacral or presacral tumors.

1.5 vs 3 tesla

An MRI examination of the sacroiliac joints is generally performed on both 1.5 and 3 tesla.

Patient positioning

An MRI of the sacroiliac joints is conducted with the patient in the supine position.

Technical parameters

Coil

Multi-phased array coils are recommended.

• anterior surface coil
• posterior coil

Scan geometry

• in-plane spatial resolution: ≤0.4 x 0.4 mm
• field of view (FOV): 240-300 mm, as small as possible
• slice thickness: ≤3 mm, interslice gap of 0.3 mm

Planning

• coronal oblique images:
  • angulation: along the axis of the posterior surface of the S2 vertebral body
  • volume: covers the whole sacrum
  • slice thickness: ≤3 mm
  • angulation: perpendicular to the coronal oblique slice
  • volume: including the whole sacroiliac joint, from disc space L5/S1 to S5
  • slice thickness: ≤3 mm
  • angulation: strictly sagittal to the body axis
  • volume: depends on the pathology
  • slice thickness: ≤3 mm

  Sequences

  Sequences can be adjusted to scanner specifications, and image quality in particular sequences. As with other musculoskeletal imaging water-sensitive sequences are an integral component, such as STIR, T2 weighted fat-saturated images or intermediate weighted images.

  For the assessment of the sacroiliac joint at least one T1-weighted sequence should be included.

  In the setting of suspected sacroiliitis, an MRI of the sacroiliac joints benefits from contrast media for the assessment of synovitis, capsulitis and/or enthesitis. According to the 2015 EULAR recommendations, it is, however, sufficient to detect bone marrow edema 3 .

  Standard sequences

  A typical MRI of the sacroiliac joints might look as follows 1 :

  • T2-weighted (fat-saturated) or STIR or intermediate (fat-saturated)
    • purpose: bone and/or soft-tissue characterization, for the detection of bone marrow edema
    • technique: T2 FS fast spin echo / STIR / IM FS fast spin echo
    • planes: coronal oblique, axial oblique
    • purpose: bone and/or soft-tissue characterization and the detection of fatty infiltration and bone erosions including backfill
    • technique: T1 fast spin echo
    • planes: coronal oblique

    Optional sequences

    • T2-weighted
      • purpose: bone and soft tissue characterization, tumors
      • technique: T2 fast spin echo, T2 Dixon
      • planes: sagittal * (option for sacral or presacral tumors)
      • purpose: for the assessment of synovitis, capsulitis and enthesitis
      • technique: T1 fast spin echo
      • planes: coronal oblique, axial oblique

      (*) indicates optional planes

      Practical points

      • a typical protocol will consist of 3-5 sequences, depending on if contrast is given or not
      • an alternative to the STIR or T2 weighted or intermediate weighted (fat-saturated) axial stack would be a T2 weighted or proton density-weighted Dixon variant, which includes a fluid sensitive fat-saturated and a non-fat-saturated image stack
      • likewise, the protocol can be supplemented with sagittal sequences for the assessment of sacral tumors

      References

      • 1. Sudoł-Szopińska I, Jurik AG, Eshed I, Lennart J, Grainger A, Østergaard M, Klauser A, Cotten A, Wick MC, Maas M, Miese F, Egund N, Boutry N, Rupreht M, Reijnierse M, Oei EH, Meier R, O'Connor P, Feydy A, Mascarenhas V, Plagou A, Simoni P, Platzgummer H, Rennie WJ, Mester A, Teh J, Robinson P, Guglielmi G, Åström G, Schueller-Weiderkamm C. Recommendations of the ESSR Arthritis Subcommittee for the Use of Magnetic Resonance Imaging in Musculoskeletal Rheumatic Diseases. (2015) Seminars in musculoskeletal radiology. 19 (4): 396-411. doi:10.1055/s-0035-1564696 - Pubmed
      • 2. MRI protocols of the ESSR Arthritis Sub-Committee ESSR Arthritis Subcommittee MRI protocols
      • 3. Mandl P, Navarro-Compán V, Terslev L, Aegerter P, van der Heijde D, D'Agostino MA, Baraliakos X, Pedersen SJ, Jurik AG, Naredo E, Schueller-Weidekamm C, Weber U, Wick MC, Bakker PA, Filippucci E, Conaghan PG, Rudwaleit M, Schett G, Sieper J, Tarp S, Marzo-Ortega H, Østergaard M. EULAR recommendations for the use of imaging in the diagnosis and management of spondyloarthritis in clinical practice. (2015) Annals of the rheumatic diseases. 74 (7): 1327-39. doi:10.1136/annrheumdis-2014-206971 - Pubmed
      • 4. Tsoi C, Griffith JF, Lee RKL, Wong PCH, Tam LS. Imaging of sacroiliitis: Current status, limitations and pitfalls. (2019) Quantitative imaging in medicine and surgery. 9 (2): 318-335. doi:10.21037/qims.2018.11.10 - Pubmed