Scintigraphic findings on 99mTc-MDP, 99mTc-sestamibi and 99mTc-HMPAO images in Gaucher's disease.

Gaucher s disease is an autosomal recessive lysosomal storage disease characterized by the specific deficiency of glucocerebrosidase that leads to accumulation of insoluble glucocerebroside in the reticuloendothelial system, particularly the bone marrow, liver, spleen and lymph nodes. Direct scintigraphic visualization of lipid deposits in Gaucher s disease has recently been described, based on the use of the lipid-soluble xenon-133. We report here on the use of the lipophilic cationic complex technetium-99m sestamibi (99mTc-MIBI), employed as an indicator of increased cellular density and metabolic activity, to evaluate Gaucher cell infiltrates in the bone marrow; 99mTc-hexametazime (99mTc-HMPAO) was also employed, as a pure indicator of lipidic infiltration in the bone marrow. A 67-year-old patient with known type 1 Gaucher s disease presented with a painful left hip and knee and difficulty in gait subsequent to traumatic fracture of the left femoral neck that had required implant of a fixation screw-plaque. Bone scan with 99mTc-methylene diphosphonate revealed reduced uptake at the distal metaphyseal-epiphyseal femoral region. In addition, whole-body maps and spot-view acquisitions of the thighs and legs were recorded at both 30 min and 2.5 h after the injection of 99mTc-MIBI: the scintigraphic pattern clearly showed increased uptake at several sites involved by Gaucher deposits in the bone marrow (both knees, with variable intensity in different areas), matching the bone changes detected by conventional x-ray. The target to non-target ratios slowly decreased with time, from an average value of 2.25 in the early scan to an average value of 2 in the delayed scan. The lipid-soluble agent 99mTc-HMPAO exhibited a superimposable scintigraphic pattern of accumulation at the involved sites, though with lower target to non-target ratios (1.27-1.48). The results obtained in this patient suggest a potential role of 99mTc-MIBI in the scintigraphic evaluation of Gaucher s lipid deposits in the bone marrow. If the results are confirmed in other patients, this radiopharmaceutical would offer clear advantages over 133Xe because of its wider availability and greater practicality (i.v. administration of 99mTc-MIBI versus inhalation of 133Xe, and use of a single gamma camera instead of two as with 133Xe).