This chapter focuses on two slow-flow vascular malformations of the brain: brain capillary telangiectasias (BCTs) and developmental venous anomalies (DVAs). Both occur as incidental findings in the general population, are typically asymptomatic when existing as solitary lesions, and can occur along a spectrum of being barely visible (usually only on postcontrast imaging) to being quite large to the point of simulating symptomatic lesions such as a neoplasm (owing to avid enhancement and size in a BCT) or frank arteriovenous malformation (AVM, due to large venous flow voids in a DVA). Besides size, they can both occur concomitantly in symptomatic cases when associated with symptomatic slow-flow vascular lesions, typically cavernomas (e.g., cavernous hemangiomas, cavernous malformations). Both lesions have dedicated, longer discussions in this chapter about the spectrum of their appearance on various sequences and when they can simulate symptomatic lesions as well as their appearance on more recently available MR sequences, most notably susceptibility-weighted imaging (SWI). Comparison cases are provided at the end of the chapter for both lesions, with a focus on cavernomas and AVMs.