In COVID-19 pandemic, adding Furosemide diuretic to conventional bone scintigraphy minimizes patient’s waiting time without affecting image quality.

Introduction: During the COVID-19 pandemic, application of protective measures in nuclear medicine studies is mandatory, this could be applied during bone scintigraphy that needs a long waiting time after Tc-99m Methylene-diphosphonates [Tc-99m MDP] injection from 2-4 hours before imaging to allow for tracer localization in bone and background clearance.

Aim of work: To assess if furosemide diuretic injection could fasten soft tissue clearance and thus increase the bone to background contrast allowing for early imaging within one hour after radiotracer injection without affecting image quality and interpretation, and if this could minimize patient’s waiting time during the pandemic of COVID-19 particularly in a busy department with a large number of patients.

Methods: Our ongoing prospective study was done on 150 patients who were referred for conventional skeletal scintigraphy for various oncological indications. Patients were equally divided into 3 groups (50 patients in each group). Patients in group 1 were intravenously injected with Furosemide at the same time as radiotracer injection in a dose of 0.5 mg/kg, a maximum of 40 mg, and they were imaged after 1 hour. Group 2 patients were imaged after 1 hour without diuretic injection whereas patients in group 3 were routinely imaged after 3 to 4 hours without diuretic injection. Image quality was assessed qualitatively by a semiquantitative score and quantitively by drawing equal rectangular regions of interest (ROI) over the femoral diaphysis and the contralateral thigh region on the soft tissue area. The total number of counts from the bone [B] ROI and soft tissue [ST] ROI was expressed as a ratio [B: ST ratio]. Mean values of B: ST ratios were statistically compared.

Results: Patients in all groups were matched regarding age, gender, and body mass index, all had normal creatinine levels. Mean values of B: ST ratios were 1.7±0.29 for group 1, 1.64±0.27 for group 2, and 1.8±0.36 for group 3. No statistically significant difference was found between group 1 and group 3 [p=0.45] while a statistically significant difference was found between groups 1 and 2 [p=0.02] and between groups 3 and 2 [p=0.01].

Conclusions: Adding diuretic injection during skeletal scintigraphy could reduce waiting time to only 1 hour without affecting image quality with proper qualitative image interpretation. This protocol could be applied in busy departments especially in the era of the COVID-19 pandemic.