Systems and methods are provided for injecting one or more agents into tissue within a patient's body. In one embodiment, an injection device includes a substantially axially incompressible elongate member including a lumen extending between proximal and distal ends thereof. A distal stop is provided on the distal end and a needle tip extends distally beyond the distal stop, the needle tip having a cross-section smaller than the distal end. The needle tip includes a passage communicating between the lumen and an outlet in the distal tip that has having a cross-section smaller than the lumen. In an exemplary embodiment, the elongate member includes a coil extending between the proximal and distal ends, and a sleeve disposed within an interior region of the coil extending between the proximal and distal ends. The sleeve defines the lumen and may be free-floating within at least a portion of the coil.
