There is a high recurrence rate after sclerotherapy of low-flow vascular malformations. Conventional treatment uses fluoroscopy and ultrasound to assess the diffusion of the sclerosing agent during therapy. These modalities give a limited two-dimensional image. Employing intraprocedural cross-sectional imaging (ICSI) has the potential to give a three-dimensional assessment of the sclerosant’s diffusion. The purpose of this study was to evaluate the impact of ICSI on immediate outcomes of sclerotherapy of low-flow vascular malformations. A retrospective review was performed of all low-flow vascular malformation sclerotherapy procedures since the introduction of ICSI. Procedural metrics collected include type of ICSI used, quality of ICSI, assessment of sclerosing agent diffusion, percentage of lesion infusion, influence of ICSI on subsequent treatment planning, extravasation detection, and recurrence rate. There were 19 sclerotherapy procedures (11 venous malformations, 8 lymphatic malformations) performed in 16 patients using ICSI. All intraprocedural cross-sectional images were successfully acquired with fluoroscopy suite cone beam computed tomography, diagnostic computed tomography scanner, or diagnostic magnetic resonance imaging scanner (52.6% vs 42.1% vs 5.2%, respectively). Image quality was rated excellent or good for 78.9% of studies. ICSI improved assessment of therapeutic agent diffusion in 89.4% of cases compared with the other concurrent imaging modalities (ultrasound, fluoroscopy, and digital subtraction angiography, alone or in combination). ICSI demonstrated percentage of lesion infusion at 67.6% (95% confidence interval, 61%-73%). ICSI detected extravasation in 10.5% of cases. ICSI influenced management decisions in 52.6% of cases including needle repositioning, additional treatment access sites, and planning for future therapy sessions. In comparison to conventional imaging, ICSI provides additional information to aid in intraprocedural management of low-flow vascular malformations. ICSI may help optimize therapy in performing sclerotherapy of these lesions.