Early and delayed Tc-99m ECD brain SPECT in SLE patients with CNS involvement

Area of Science:

• Neurology
• Nuclear Medicine
• Immunology

Background:

• Systemic Lupus Erythematosus (SLE) can affect the central nervous system (CNS), leading to neuropsychiatric disorders.
• Diagnosing CNS involvement in SLE can be challenging, necessitating sensitive imaging techniques.

Purpose of the Study:

• To compare early and delayed Technetium Tc-99m ethyl cysteinate dimer (ECD) SPECT scans in SLE patients with and without neuropsychiatric symptoms.
• To evaluate the utility of SPECT imaging in detecting and assessing CNS involvement in SLE.

Main Methods:

• 32 SLE patients (Group 1: definite neuropsychiatric disorders; Group 2: minor neurologic symptoms or normal) and normal controls underwent early and delayed Tc-99m ECD SPECT scans.
• Visual inspection and semi-quantitative evaluation (cerebral region to cerebellar ratios) were used to analyze scan results.
• Retention rates in various cortical regions were calculated.

Main Results:

• Early scans showed diffuse uneven decreases in 93% of Group 1 and 39% of Group 2 patients.
• Delayed scans revealed focal decreases in the medial frontal lobe in 39% of Group 2 patients with normal early scans.
• SPECT analysis indicated significantly lower regional brain perfusion and retention rates in SLE patients compared to controls, with delayed scans showing widespread cortical involvement.

Conclusions:

• Delayed Tc-99m ECD brain SPECT demonstrates high sensitivity for detecting CNS involvement in SLE patients.
• SPECT findings provide objective diagnostic information in SLE, even when not correlating with clinical symptoms.
• No SPECT improvement was observed despite clinical improvement in follow-up studies.