A 62 year old male presented with long-term back pain, which was inflammatory/mixed in rhythm and had been progressively worsening. He also presented with pain in his hips, knees, and feet, with no other signs or symptoms of osteoarthritis.

Physical examination of the patient revealed that his movement was limited in all axes and Schöber's test was 3cm.

Our hospital performed X-rays of the cervical, dorsal, lumbar and pelvic spine which showed a calcification of the anterior common vertebral ligament with preservation of the disc spaces (Figs. 1 and 2).

Fig. 1.

Cervical spine X-ray: the height of the vertebral bodies are preserved. Calcification projected onto the soft tissues in the dorsal section in the occipito-vertebral ligament.

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Fig. 2.

Dorsal spine X-ray: calcification of the common anterior vertebral ligament.

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In view of these findings the patient was referred to the nuclear medical unit for a bone scan to rule out several causes of osteoarthritis, Forestier's disease among them.

Forestier's disease is related to abnormal bone growth.1–3 The main disease symptoms is calcification of the longitudinal ligaments of the spine, involving at least 4 contiguous vertebrae. Other criteria are the preservation of intervertebral disc spaces and the absence of inflammatory changes in intrapophysary or sacroiliac joints.4–6

In the bone scan images there was no sign of articular pathological uptake (Fig. 3). Multimodality SPECT/CT tomographic images were then acquired (Figs. 4 and 5), which were used both for qualitative visual analysis of the sacroiliac joint, and for quantitative analysis which permitted the obtainment of indicators of the sacroiliac-promontory. In visual analysis calcification of the anterior common vertebral ligament was detected, together with absence of sacroiliac uptake. With this information and inferior promontory-sacroiliac indicators below the established cut-off level for diagnosis of sacroiliitis, diagnosis of ankylosing spondylitis was excluded, with support for the diagnosis of Forestier's disease.

Fig. 3.

Bone scan with normal pattern of uptake on the cervico dorsal skeleton and discrete uptake on the right-hand side of the lumbar rachis.

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Fig. 4.

SPECT/CT slice images in axial, sagittal and coronal planes with low uptake of the radiopharmaceutical in sacroiliac joints. Sacroiliac/promontory values below cut-off level established for diagnosis of sacroiliitis.7,8

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Fig. 5.

SPECT/CT: calcification of common anterior vertebral ligament and preservation of intervertebral disc spaces.

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