A medical instrument system, comprising: an imaging probe including a distal tip terminating at a first distal end of the imaging probe; an elongated medical instrument having a distal portion terminating at a second distal end, the elongated medical instrument including a working channel; characterized by: the distal tip including a first sealing feature; the elongated instrument including a second sealing feature on a surface of the working channel, wherein the first sealing feature and the second sealing feature are shaped and configured to contact one another to prevent passage of fluid between the first and second sealing features; a first interlocking feature comprising a first collar including a plurality of protrusions on an external surface of the imaging probe, the first collar having a first three-dimensional shape; and a second interlocking feature comprising a second collar including a plurality of indentations on an internal surface of the working channel, the second collar having a second three-dimensional shape complementary to the first three-dimensional shape, wherein the plurality of protrusions are configured to mate with the plurality of indentations, wherein the distal tip of the imaging probe further includes a fluid direction surface, wherein when the first and second sealing features are in contact, a gap is formed between the fluid direction surface and the second distal end of the elongated medical instrument to direct the passage of fluid from the working channel across the distal tip of the imaging probe; and wherein the first interlocking feature and the second interlocking feature are configured to mate and releasably interlock the imaging probe in a predetermined arrangement relative to the elongated medical instrument. an imaging probe including a distal tip terminating at a first distal end of the imaging probe; an elongated medical instrument having a distal portion terminating at a second distal end, the elongated medical instrument including a working channel; characterized by: the distal tip including a first sealing feature; the elongated instrument including a second sealing feature on a surface of the working channel, wherein the first sealing feature and the second sealing feature are shaped and configured to contact one another to prevent passage of fluid between the first and second sealing features; a first interlocking feature comprising a first collar including a plurality of protrusions on an external surface of the imaging probe, the first collar having a first three-dimensional shape; and a second interlocking feature comprising a second collar including a plurality of indentations on an internal surface of the working channel, the second collar having a second three-dimensional shape complementary to the first three-dimensional shape, wherein the plurality of protrusions are configured to mate with the plurality of indentations, wherein the distal tip of the imaging probe further includes a fluid direction surface, wherein when the first and second sealing features are in contact, a gap is formed between the fluid direction surface and the second distal end of the elongated medical instrument to direct the passage of fluid from the working channel across the distal tip of the imaging probe; and wherein the first interlocking feature and the second interlocking feature are configured to mate and releasably interlock the imaging probe in a predetermined arrangement relative to the elongated medical instrument. the distal tip including a first sealing feature; the elongated instrument including a second sealing feature on a surface of the working channel, wherein the first sealing feature and the second sealing feature are shaped and configured to contact one another to prevent passage of fluid between the first and second sealing features; a first interlocking feature comprising a first collar including a plurality of protrusions on an external surface of the imaging probe, the first collar having a first three-dimensional shape; and a second interlocking feature comprising a second collar including a plurality of indentations on an internal surface of the working channel, the second collar having a second three-dimensional shape complementary to the first three-dimensional shape, wherein the plurality of protrusions are configured to mate with the plurality of indentations, wherein the distal tip of the imaging probe further includes a fluid direction surface, wherein when the first and second sealing features are in contact, a gap is formed between the fluid direction surface and the second distal end of the elongated medical instrument to direct the passage of fluid from the working channel across the distal tip of the imaging probe; and wherein the first interlocking feature and the second interlocking feature are configured to mate and releasably interlock the imaging probe in a predetermined arrangement relative to the elongated medical instrument.