Transcript M/29 C.C: Right hip pain

M/29
C.C: Right hip pain
T1
T2
Gd-enhanced FS T1
T2
Gd-enhanced FS T1
Answer: Tuberculous arthritis
Findings:
- Anteroposterior view of the hip shows periarticular osteoprosis, bony
erosions, subchondral cysts with internal radiopaque density and capsular
distension. Joint space narrowing of superior direction is also noted.
- Axial MR images of right hip demonstrate bony erosions and joint capsular
distension by the materials with central low and peripheral intermediate signal
intensities on T2-weighted image and only peripheral enhancement on
enhanced fat-suppressed T1-weighted image. The peripheral rims along the
capsule has irregular thickness. Periarticular abscess adjacent to obturator
externus muscle is seen.
- Coronal MR images reveals subchondral lesions at both acetabulum and
femoral head. The lesions shows low signal intensities with dark signal foci in
central part and intermediate to high signal intensity in peripheral part,
suggesting tuberculomas.
Diagnosis:
Tuberculous arthritis, right hip.
Differencial diagnosis:
Pyogenic arthritis, Rheumatoid arthritis
Discussion:
On plain radiograph, tuberculous arthritis usually shows Phemister’s triad;
juxta-articular osteoporosis, peripherally located osseous erosions and
progressive joint space narrowing.
The MR findings of tuberculous arthritis are subchondral erosion, synovial
proliferation and periarticular soft tissue abscess formation. The presence of a
tuberculoma in intraarticular space or periarticular soft tissue is a specific
finding in tuberculous arthritis, and it can differenciate them from pyogenic
arthritis.
Tuberculoma is composed of a central caseous necrosis and peripheral
capsule with fibroblasts, epithelioid cells, macrophages and lymphocystes.
Tuberculoma on MR scans demonstrates heterogeneously intermediate or
variable signal intensities and peripheral rim enhancement on T1-weighted
image and central low signal intensity with a few dark signal foci and
peripheral intermediate signal intenty on T2-weighted image. The dark signal
foci on T2-weighted image may be due to free radicals with irregular
distribution and immobile saturated fatty acids, leading to T2-shortening.
On the other hand, abscess of tuberculous arthritis shows various signal
intensities and enhancing peripheral wall with smooth inner margin on T1weighted image and high signal intensity on T2-weighted image.
References
1. Jan HW, Kim JW, Cho KH. MR findings of tuberculous arthritis: significance
of tuberculoma. J Korean Radiol Soc 2001;44:237-241
2. Kim TK, Chang KH, Kim CJ, Goo JM, Kook MC, Han MH. Intracranial
tuberculoma: Comparison of MR with pathologic findings. AJNR Am J
Neuroradiol 1995;16:1903-1908
3. Suh JS, Lee JD, Cho JH, Kim MJ, Han DY, Cho NH. MR imaging of
tuberculous arthritis: clinical and experimental studies. J Magn Reson
Imaging. 199;6(1):185-189