Ga-67 scintigraphy in lupus nephritis.

Lupus nephritis is a disease characterized by flareups and remissions. Evaluation of disease activity is important for therapeutic decisions and prognosis. In this study, 46 patients with lupus nephritis were evaluated by Ga-67 scintigraphy. Delayed 48-hour Ga-67 images were performed to evaluate kidney uptake. A patient with a 24-hour urinary protein excretion of 3 g or more or a serum creatinine level greater than 1.5 mg/dl was considered to have active lupus nephritis. Renal disease was active in 22 patients and inactive in 24 patients. Of the 22 patients with active renal disease, 18 (81.8%) showed positive Ga-67 results, whereas only 12.5% (3 of 24) of patients with inactive renal disease showed a positive Ga-67 study. The difference between the two groups was significant. Patients with positive Ga-67 scans had a significantly higher serum creatinine level and 24-hour urine protein value than patients with negative Ga-67 scans. In addition, all of the patients (100%) with a 24-hour urine protein greater than 4 g/day had a positive Ga-67 scan. It appears that Ga-67 scintigraphy is useful for the evaluation of disease activity in lupus nephritis.