The crowned dens syndrome. Evaluation with CT imaging

Area of Science:

• Radiology
• Rheumatology
• Orthopedics

Background:

• Crowned dens syndrome involves calcification around the odontoid process, often associated with crystal deposition diseases like calcium pyrophosphate dihydrate (CPPD) deposition disease.
• Symptoms can mimic other conditions, making diagnosis challenging. The spine can be the sole site of CPPD involvement.

Purpose of the Study:

• To evaluate the diagnostic utility of computed tomography (CT) for crowned dens syndrome.
• To assess CT's value in identifying calcifications in crystal deposition diseases and other rheumatic/nonrheumatic conditions affecting the atlantoaxial region.

Main Methods:

• Thirty-eight patients with neck pain underwent unenhanced CT of the cervical spine.
• Patients were categorized into those with known rheumatic conditions and those with cervical spine symptoms and inconclusive radiography.
• The study included patients with rheumatoid arthritis, CPPD, systemic sclerosis, osteoarthritis, neoplasm, trauma, and other conditions.

Main Results:

• CT identified calcific deposits around the dens in 12 patients, forming horseshoe- or crown-like patterns.
• Irregular calcifications of the atlantoaxial joint were observed in other rheumatic diseases, particularly rheumatoid arthritis.
• CT accurately depicted the shape and site of calcification and bone erosions.

Conclusions:

• Computed tomography (CT) is the gold standard for diagnosing crowned dens syndrome due to its ability to visualize calcifications and bone erosions.
• Radiography of other joints can help differentiate crystal types (CPPD vs. hydroxyapatite).
• Magnetic resonance imaging (MRI) is recommended for evaluating neurological complications.