PAGET'S DISEASE

Mid Sagittal T2 wt and Para Sagittal T1 wt Images: Mild increase in the AP diameter of L3 vertebral body with thick coarses trabeculations. Irregular T1hypointensity noted in the posterior body and posterior elements of L3.



Axial T2 wt image at L3 level and coronal STIR image : Cortical thickening and irregularity with trabecular thickening. STIR hyperintense signals seen in vertebral body



Mid sagittal T2 wt image of cervical spine: Diffuse uniform thickening of
cranial vault with hyperintense marrow. 



Axial CT sections of L3 veretebra at the level of body and spinous process:
There is irregular thickening of the cortex in the body with preservation of marrow and spinal canal.
Few thick coarse trabeculae are seen with osteolysis of the rest.
Diffuse sclerosis with few lytic areas seen in the posterior elements..

 



Sagittal and Coronal reformatted images of lumbar spine: Mild expansion of the L3 vertebral body in the transverse and antero-posterior directions with few thickened trabeculae and lysis of the rest.
Mild expansion with sclerosis of the spinous process.





Also called as osteitis deformans.

The spine is the second most commonly affected site after the pelvis.

Three phases:

1.      Osteolytic

2.      Mixed

3.      Osteoblastic

Most common sites of involvement: Lumbar spine> pelvis> sacrum> femur> cranium.

Radiography:

Blade of grass- early lytic phase in long bones. Spreads about 1cm per year and has no sclerotic margin.

Osteoporosis circumscripta: large areas of advancing osteolysis in frontal and occipital regions of cranial vault. More prominent in inner table and can cross sutures.

In mixed phase - Picture frame vertebra and cotton wool appearance of skull. Ileopectineal and ischiopubic line thickening.

In late blastic phase: Banana fractures, Tam-o-shanter skull, Ivory vertebra.

Radionuclide scan:

shows increased uptake in all the three phases, but more so in active phase.

CT scan:

Shows the classic features of Pagets conspicuously and helps in evaluation of    complications like fractures, spinal stenosis and malignancy.

MRI:

            MR signal changes reflect the natural coarse of disease.

            Three major patterns:

1.      Similar to fat- corresponds to long standing disease.

2.      Heterogenous low signal on T1 and high signal on T2 - early mixed active phase

3.      Low signal on both T1 and T2 - late blastic inactive phase.

Complications:

1.      Arthropathy

2.      Deformity/ fracture

3.      Nerve entrapment

4.      Neoplasms – sarcomatous transformation(osteosarcoma > MFH > chondrosarcoma > lymphoma & angiosarcoma.

References:

·        Imaging of Paget Disease of Bone and Its Musculoskeletal Complications: Review   AJR:196, June 2011.

·        The spine in Paget’s disease, Skeletal Radiol (2007) 36:609–626