Optimizing the Quality of 4D-DSA Temporal Information

Abstract

BACKGROUND AND PURPOSE: Quantification of blood flow using a 4D-DSA would be useful in the diagnosis and treatment of cerebrovascular diseases. A protocol optimizing identification of density variations in the time-density curves of a 4D-DSA has not been defined. Our purpose was to determine the contrast injection protocol most likely to result in the optimal pulsatility signal strength. MATERIALS AND METHODS: Two 3D-printed patient-specific models were used and connected to a pulsatile pump and flow system, which delivered 250-260 mL/min to the model. Contrast medium (Isovue, 370 mg I/mL, 75% dilution) was injected through a 6F catheter positioned upstream from the inlet of the model. 4D-DSA acquisitions were performed for the following injection rates: 1.5, 2.0, 2.5, 3.0 and 3.5 mL/s for 8 seconds. To determine pulsatility, we analyzed the time-density curve at the inlets using the oscillation amplitude and a previously described numeric metric, the sideband ratio. Vascular geometry from 4D-DSA reconstructions was compared with ground truth and micro-CT measurements of the model. Dimensionless numbers that characterize hemodynamics, Reynolds and Craya-Curtet, were calculated for each injection rate. RESULTS: The strongest pulsatility signal occurred with the 2.5 mL/s injections. The largest oscillation amplitudes were found with 2.0-and 2.5-mL/s injections. Geometric accuracy was best preserved with injection rates of .1.5 mL/s. CONCLUSIONS: An injection rate of 2.5 mL/s provided the strongest pulsatility signal in the 4D-DSA time-density curve. Geometric accuracy was best preserved with injection rates above 1.5 mL/s. These results may be useful in future in vivo studies of blood flow quantification.

4D-DSA: Development and Current Neurovascular Applications

“…showed that when using a proper protocol for the injection of contrast medium, both the spatial information of 3D-DSA (geometry) and the temporal information of 4D-DSA (flow) remained highly accurate. 12 Additionally, Sandoval-Garcia et al 16 also found complete agreement in diagnostic characteristics in images from 2D-, 3D-, and 4D-DSA datasets. For endovascular treatment of aneurysms, it is critical that precise information on vessel sizes, ostium characteristics, and parent artery branch relationships be available.…”

“…Without the pulsatile information from the contrast bolus mixing with nonopacified blood between systole and diastole, it would be impossible to quantify blood flow using 4D-DSA data. 11,12 Ruedinger et al 12 reported that an injection protocol of 75% contrast (iopamidol, Isovue 370; Bracco) injected at 2.5 mL/s for 8 seconds satisfies these requirements by producing strong pulsatility in the area of interest.…”

“…The temporal information contained in 4D-DSA is sufficient to quantify blood velocity, and when combined with accurate vessel measurements, blood flow can be quantified. 12,23 Flow derivation is based on identifying the time needed for a contrast bolus to pass between 2 points; this movement is captured in the time-density curves (TDCs) of 4D-DSA (also called time-concentration curves). Each voxel contains a TDC depicting bolus inflow, steady state, and bolus outflow.…”

Recent progress understanding pathophysiology and genesis of brain AVM—a narrative review

“…2) [2]. Similarly, the teams of Ogard, and also Sandoval-Garcia used advanced angiographic exploration in AVM patients with both 4D DSA and 2D DSA [37,38,45,46]. A good agreement between the techniques was found regarding Spetzler-Martin grade and nidus size, but less for defining the venous drainage.…”

Machine Learning Application With Quantitative Digital Subtraction Angiography for Detection of Hemorrhagic Brain Arteriovenous Malformations

“…Third, even though two projections of 2D-DSA were acquired simultaneously, it was not possible to fully compensate for the overlapping of vasculatures. A 4D-DSA technique has been developed recently, offering both three-dimensional structure and temporal cerebrovasculature information [29]. This is a solution to the problem of overlapping vessels and has the potential to achieve better performance than 2D-DSA in the application of QDSA.…”