Paget Disease: Spiral CT Findings in 3D Reconstruction

Clinical History

An 85 year-old female was admitted to our hospital complaining pain in posterior region of the skull and convulsions. The cranial x-ray showed thickness of the skull bones. Multislice spiral CT showed at the level of theca and skull base bones, lythic and sclerotic degenerations.

Imaging Findings

An 85 year-old female was admitted to our hospital complaining pain in posterior region of the skull and convulsions. The cranial x-ray showed thickness of the skull bones and laboratory examinations demonstrated normal values of calcemia and phosphoremia, but elevated serum alkaline phosphatase levels. Multislice spiral CT examination was subsequently performed: at the level of theca and skull base bones, lythic and sclerotic degenerations were observed; theca bones thickness appeared increased; maxillo-facial bones were less involved. CT data were transferred to a dedicated workstation and 3D images of the skull were analyzed using volume rendering as reconstruction algorithm

Discussion

Paget's disease of bone is a metabolic disorder characterized by an excessive bone remodelling due to activated osteoclasts leading to hypertrophy and abnormal bone structure. This pathology affects 10% of people over 80 years of age. Its origin is still unknown. It could be caused by a virus, however, although this hypothesis has not been definitively proved. Indirect data exist, such as the presence of intranuclear inclusions in the osteoclasts in patients with Paget's disease. Some Authors have indicated the respiratory syncitial virus as the most probable etiological agent, however, more studies are necessary to prove these hypothesis. Signs and symptoms, when present, depend on the disease location and on the degree of bone remodelling: bone pain, non-traumatic fractures, headache, convulsions, hypoacusia, and neurological complications. Diagnosis is based on clinical features, elevated bone-specific alkaline phosphatase levels and imaging examinations (mainly X-ray and CT). 3D reconstruction in spiral CT is used to obtain a better visualization of the involved body regions. Procedure starts with data post-processing by means of a workstation with dedicated software volume rendering capabilities. Volume rendering is a technique of 3D recontruction based on imaging acquisition supported by gray scale, which represents a specific density in different body regions. Using dedicated curves of workstation by modulating relative opacities and transparencies we obtain a visualization of the different structures. For a better visualization of bones, we can exclude all other districts of the body with a subtraction imaging technique.

Differential Diagnosis List

Final Diagnosis

Paget disease

URL:	https://eurorad.org/case/1093
DOI:	10.1594/EURORAD/CASE.1093
ISSN:	1563-4086