Magnetic resonance evaluation of tubercular lesion in spine

Abstract

Purpose: Information on Magnetic Resonance (MR) features of active and healed lesions in tuberculosis (TB) spine are lacking. We evaluated MRI findings in active and healed proven TB spine to establish the diagnostic features.

Materials and method: Forty-nine consecutive spinal TB patients (20 male; 29 female) diagnosed clinicoradiologically and/or on histopathology, Fine Needle Aspiration Cytology (FNAC), bacteriology, or Polymerase Chain Reaction (PCR) were enrolled. Pretreatment MR scans were reviewed for diagnostic features, and eight-month follow-up MR scans were reviewed for healing changes.

Results: Cervical spine (n = 6), dorsal spine (n = 14), and lumbar spine (n = 29) were affected. Fourteen had paraplegia. Mean vertebrae involved were 2.61 on X-ray with a total of 128 vertebrae (VB) and 3.2 on MRI (range, 2-15) with 161 VB. The lesions were more extensive on MRI (34.7%) than appreciated on X-ray. The disc was preserved partially or fully in 88.2% of instances. End plate erosions (159/161 VB), lost VB height (94/161), exudative lesion (158/161), granular lesion (3/161), pre and paravertebral collections (49/49 cases), marrow oedema (161/161), discitis (98%), epidural involvement (107/161), epidural spread (100/161), and subligamentous spread (156/161) were observed. Canal encroachment (10-90%) was seen in 37 cases. Mean motor and sensory scores with greater than 50% canal encroachment were 87/100 and 156/168, respectively. Cord oedema was observed in 11 cases (eight with neural deficit and three cases without). Cord atrophy was seen in one case each before and after treatment. A total of 83% of patients had a combination of paravertebral collections, marrow oedema, subligamentous and epidural extension, endplate erosions and discitis. On healing (n = 20), complete resolution of marrow oedema and collections, fatty replacement of bone marrow and resolution of cord signal intensity were observed.

Conclusion: The marrow oedema, preservation of disc space, subligamentous extension of abscess, septate paravertebral abscess, epidural extension, endplate erosions and discitis were consistently observed in 83% cases of TB spine on MRI.

Fig. 1

a Plain X-ray lateral view shows paradiscal lesion D9D10 with destroyed paradiscal margins with endplate erosions and decrease in vertebral height of D10. b, c Sagittal section T1W and T2W show paradiscal lesions with intraosseous caseation with preserved discs with anterior subligamentous spread of prevertebral collection with anterior epidural spread of collection compressing spinal cord. d, e Axial section T1W and T2W show large septate prevertebral collection, intraosseous caseation with large anterior epidural collection and 75% canal encroachment

Fig. 2

a Plain X-ray lateral view (pretreatment) shows decreased disc space in L2-L3 vertebral bodies. b Sagittal section of T2W MRI shows paradiscal lesion (hyperintense signal suggestive of marrow oedema) in L2-L3 with discitis with small anterior epidural collection. c Sagittal section of T1W MRI shows hypointense signal in L2-L3 paradiscal region. d, e Eight months nonoperative post-treatment MRI scan sagittal section T2W and T1WI shows resolution of anterior epidural collection and bone oedema. Hyperintense signal in L2-L3 VB suggestive of fatty infiltration of marrow. f, g Pretreatment axial T1WI and T2WI show a thin rim of paravertebral collection towards the left side with evidence of bone oedema, which has resolved on post treatment axial T1WI (h) and T2WI (i)

Fig. 3

a Plain X-ray lateral view (pre treatment) shows erosion of endplates with fuzzy paradiscal margins (L4) with loss of vertebral height in L3, L4. b Plain X-ray lateral view (8 months post-treatment) shows sclerosis of endplate of L3, L4 with sharpening of paradiscal margins. c,d,e Pre treatment sagittal section T2W, STIR and T1W shows paradiscal lesion L3,L4 with anterior subligamentous spread with a small anterior epidural collection with discitis and preserved discs. Marrow oedema is seen as a hyperintense signal on STIR. f Eight months post treatment sagittal T1WI shows resolution of collections with hyperintense signal in T1WI suggestive of fatty marrow infiltration. g Pretreatment axial T1W image shows presence of hypointense signal and paravertebral collections. h T1WI axial scan of the same patient at 8 months posttreatment shows resolution of paravertebral collections with hyperintense signal in VB suggestive of fatty replacement of marrow as evidence of healing