Purpose: Digital Subtraction Angiography (DSA) is used to evaluate endovascular treatments, either visually or using time‐density curves (TDC), which present change of contrast as a function of time for either the entire aneurysm or sub‐volumes within (R‐TDC). Quantitative parameters such as peak‐density‐value, time‐to‐peak, input rate, influx, residence time, wash‐out‐time, and wash‐out‐rate were used in this study to examine the hemodynamic implications of several treatments using FMDs. Method and Materials: Flow evaluations for aneurysms (saccular and bifurcation geometries) were done using elastomer‐based replicas of clinical human cases. These phantoms were placed in in‐vitro pulsatile flow loops containing a blood‐simulating solution of glycerin‐water. One‐cc boluses of iodinated contrast were delivered at the proximal end of parent vessel of each aneurysm via 5‐Fr catheters using an automatic injector. DSA sequences were acquired at 30 frames/sec (5‐inch II‐mode). The necks of the aneurysms were covered using different‐porosity FMDs. TDCs were obtained pre‐and‐post‐treatment.Results: R‐TDC metrics indicate important modifications of flow occurred in different areas inside the aneurysm that are not evident from the total‐volume TDC. For example, in a sub‐region of saccular aneurysm treated with a zero‐porosity‐patch FMD, occluding the proximal portion of the aneurysmal orifice, peak‐density decreased 49% compared to untreated case and the flow behavior is changed from continuous to oscillatory, while the total aneurysm measurement shows a decrease in peak‐density of 21% and an increase of wash‐out‐time of 171% versus untreated case. In a sub‐region of the bifurcation aneurysm treated with non‐zero‐porosity patch FMD placed to occlude the entire neck, time‐to‐peak increased 67%, and input rate decreased 71% compared to untreated case, while the total aneurysm measurement shows a time‐to‐peak increase of 20% and an input rate of 50% versus untreated case.Conclusion: Proposed parameterization of TDC's is rapid and terms have physical meaning. Support: NIH R01‐NS43924, R01‐EB002873, Toshiba Corp.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging