Radiolabeled leucocyte imaging in diffuse granulomatous involvement of themeninges in Wegener's granulomatosis: Scintigraphic findings and their role in monitoring treatment response to specific immunotherapy (humanized monoclonal antilymphocyte antibodies)

BACKGROUND AND PURPOSE: Diffuse involvement of the meninges by remote granu lomas in Wegener's granulomatosis is rare. This study reports the radiolabe led leucocyte imaging findings in five such patients. The diagnosis was mad e by MR imaging in five patients and confirmed in four by findings at menin geal biopsy, The potential role of serial radiolabeled leucocyte examinatio ns in assessing treatment response is discussed. METHODS: Three of the five patients underwent whole-body planar In-111-labe led leucocyte imaging. Two of these patients had serial imaging and one had , in addition, a Tc-99m-HMPAO-labeled leucocyte single-photon emission CT b rain examination. Two of the five patients had whole-body planar Tc-99m-HMP AO-labeled leucocyte imaging. Of these, one patient had serial imaging. The radiolabeled leucocyte imaging findings were correlated with MR findings a nd with the patients' clinical course. RESULTS: In four patients there was a midline linear area of increased trac er uptake in the brain, and in one of these, tracer uptake also extended la terally over the brain convexity. In two patients linear tracer uptake exte nded in an inferolateral direction from the midline, These abnormalities co rrelated with meningeal thickening in the fair, over the brain convexity, a nd in the tentorium cerebelli on MR images. Serial imaging in three patient s revealed a reduction or disappearance in tracer uptake after treatment wi th anti-CD52, which correlated with clinical improvement. CONCLUSION: In patients with Wegener's granulomatosis, abnormal uptake corr esponding to meningeal thickening can be seen on planar radiolabeled leucoc yte Images. Leucocyte imaging may be useful for monitoring treatment respon se.