Whole body MRI in type I Gaucher patients: evaluation of skeletal involvement.

Background: Bone disease is a serious complication of type 1 Gaucher disease, which if untreated can result in pain, disability and reduced quality of life. MRI is the method of choice for assessing and monitoring bone involvement in Gaucher patients. MRI bone evaluation has been predominantly carried out on the lumbar spine and/or lower extremities using quantitative or semi-quantitative methods. We describe evaluation of skeletal involvement in Gaucher patients using whole body MRI scanning.

Methods: Whole body MRI was performed in 39 adult type I Gaucher patients using a 1.5 T superconducting magnet with total imaging matrix technology. A standard MRI protocol was performed in all patients using coronal T1-, T2-weighted (thighs) and STIR-sequences of the whole body, sagittal T1-, T2- (lumbar spine) and STIR-sequences of the entire axial skeleton. Bone marrow involvement was analysed using the Düsseldorf Gaucher score (DGS), bone marrow burden score (BMB), and vertebra-disc-ratio (VDR). Pelvis, humerus, legs and spine were also analysed using the pattern of marrow involvement described by homogeneous type A or non-homogeneous type B morphology. Avascular necrosis (AVN) of the humeral head was determined.

Results: Whole body MRI was well tolerated and of diagnostic value in all patients. Thirty one out of 39 patients (79%) showed bone involvement. In fifteen of these 31 patients (48%) humeral bone involvement was observed. The morphological appearance of bone involvement (type A or B) was consistent across the humerus, legs and pelvis. The infiltration pattern was also similar across cervical, thoracic and lumbar vertebral bodies. Humeral bone involvement was present in 89% of patients with type B morphology compared with 32% of patients with type A morphology (p<0.005). Humeral involvement was detected more frequently in patients with severe bone involvement as determined by higher DGS and BMB scores, than in patients with lower DGS and BMB scores (p<0.0001 and p=0.0016). AVN of the humeral head was detected in 6 patients (19%).

Conclusions: In this group of patients, severe bone involvement in the lumbar spine and lower extremities and type B morphology was also associated with humeral involvement. The morphological infiltration pattern was consistent in the entire skeleton indicating the systemic character of bone disease. Whole body MRI presents a feasible means of assessing the entire skeletal system and could be a valuable diagnostic and monitoring tool in the management of patients with type 1 Gaucher disease.