[Magnetic resonance and traditional radiology in the spine localizations of alkaptonuric ochronotic arthropathy].

AIM: To study the spine alterations in alcaptonuria with traditional radiology and magnetic resonance (MR), comparing the results of the two techniques.

PATIENTS AND METHODS: Five patients (4 males, 1 female, mean age 51 years) underwent the examinations. For the study with X-rays we performed anteroposterior and lateral scan and the images have been studied making reference to a radiographic score; it examines the alterations of the joint space and the presence of calcifications. MR scan, oriented in the three spatial planes, were performed using spin echo T1-weighted and spin echo T2-weighted sequences.

RESULTS: Both MR and X-rays pointed out, in the cases with known diagnosis, the typical alterations of the ochronosis: narrowing of the articular spaces, even osseous ankylosis, calcifications of the discs, osteophytosis, multiple disc protrusions and reactive sclerosis of the articular surfaces, evident above all to dorso-lumbar tract; nevertheless MR has been more accurate than X-rays for individualizing the lesions and recognizing alterations, such as the thickness of the anterior longitudinal ligament. In the case of new diagnosis, the MR is fundamental to recognize typical signs of the ochronotic arthropathy not well detected by X-rays.

CONCLUSIONS: Imaging techniques, first of all the MR, are essential in the differential diagnosis of ochronosis vertebral lesions with other articular diseases.