Figure 3. Semi-quantitative analysis identified significant reduction of radiopharmaceutical uptake in the upper, middle and lower regions of the left lung with respect to the right (A) and confirmed left lung hypo-perfusion (B), thus requiring further surgery. LPS has an important role in the diagnosis, as part of work-up for better patient management, and during follow-up to confirm surgery or therapy success in patients with CHD (6). Our case is a demonstrative example of LPS usefulness in the evaluation of lung hemodynamic effects in pediatric patients with TOF, allowing an accurate evaluation of the best therapeutic strategy with benefits of low radiation exposure, lack of adverse effects, reproducibility, management ease and good patient compliance.