Micro-angiographic detector with fluoroscopic capability

New neuro-interventional devices such as stents require high spatial-resolution image guidance to enable accurate localization both along the vessel axis as well as in a preferred rotational orientation around the axis. A new high-resolution angiographic detector has been designed with capability for micro-angiography at rates exceeding the 5 fps of our current detector and, additionally, with noise low enough and gain high enough for fluoroscopy. Although the performance requirements are demanding and the detector must fit within practical clinical space constraints, image guidance is only needed within a ∼5 cm region of interest at the site of the intervention. To achieve the design goals, the new detector is being assembled from available components which include a CsI(T1) phosphor module coupled to a fiber-optic taper assembly with a two stage light image intensifier and a mirror between the output of the fiber taper and the input to a conventional high performance optical CCD camera. Resulting acquisition modes include 50-micron effective pixels at up to 30 fps with the capability to adjust sensitivity for both fluoroscopy and angiography. Estimates of signal at the various stages of detection are made with quantum accounting diagrams (QAD).