Does fluid restriction affect the image quality of skeletal scintigraphy?

Introduction: In Islamic countries in the month of Holy Ramadan many Muslims based on their religious Legislation refuse fluid intake during the fasting time though instructed to drink after injection of Tc-99m Methylene-diphosphonates [Tc-99m MDP] used for skeletal scintigraphy. We aimed to establish whether fluid restriction in Tc-99m MDP skeletal scintigraphy has an impact on its quality. Methods: One hundred forty-four patients referred for skeletal scintigraphy were studied. Group 1 was well hydrated while group 2 was instructed not to drink till imaging. Image quality was assessed using quantitive measures where by the end of imaging, equal regions of interest (ROI) were drawn over the femoral diaphysis, and the contralateral adductor area. The total number of counts from the bone [B] ROI and soft tissue [ST] ROI was expressed as a ratio [B: ST ratio], and a mean value for each group was established. The image quality was also assessed without knowledge of individual’s water intake by a semiquantitative score. Results: No statistically significant difference was found between the B:ST ratio means [P=0.46] and the semiquantitative scores [P=0.42] in both groups. Conclusion: Fluid restriction had no impact on the image quality in Tc-99m MDP skeletal scintigraphy though a higher radiation dose to the urinary bladder wall is anticipated.