Clinical value of gallium-67 SPECT scintigraphy in the diagnostic and therapeutic evaluation of retroperitoneal fibrosis: a prospective study.

Abstract

BACKGROUND: Gallium-67 (67Ga) scintigraphy may be useful in evaluating patients with retroperitoneal fibrosis (RPF), but a systematic assessment of its value is lacking. OBJECTIVE: Prospective evaluation of the value of 67Ga scintigraphy in assessing active RPF disease and in predicting treatment response. METHODS: Thirty-four patients with nonmalignant RPF treated with tamoxifen underwent 67Ga scintigraphy at baseline and--if baseline gallium scan was positive--at 3 months follow-up. Gallium scans were visually scored according to pathologic 67Ga-uptake compared to normal bone marrow 67Ga-uptake. Results were correlated with other (follow-up) measurements. Value of (follow-up) 67Ga scintigraphy in predicting treatment response was also assessed. RESULTS: Gallium scans were positive in 24 patients (71%). Mass thickness was greater in patients with positive gallium scan compared with patients with negative gallium scan (P = 0.006). Visual gallium score correlated with mass thickness (P = 0.006). Visual gallium score decreased significantly following tamoxifen treatment (P < 0.0001). Decrease in visual gallium score correlated with decreases in C-reactive protein and erythrocyte sedimentation rate (P = 0.019) and with decrease in mass thickness (P < 0.01). Positive predicting value (PPV) of positive baseline gallium scan was 0.71; PPV of negative follow-up gallium scan in patients with initial positive scan was 0.89. 67Ga scintigraphy detected extra-abdominal involvement in one patient and recurrent active disease in two symptomatic patients with normal acute-phase reactants and stable residual mass. CONCLUSION: 67Ga scintigraphy is useful in assessing (recurrent) activity of RPF disease and in evaluating treatment response in patients with initial positive gallium scan.