Timing-Invariant Reconstruction for Deriving High-Quality CT Angiographic Data from Cerebral CT Perfusion Data

Abstract

TI CT angiographic images constructed by using temporally filtered tMIP CT angiographic data have excellent image quality that is superior to that achieved with currently used techniques, but they suffer from modest venous superimposition.

4D-CTA in Neurovascular Disease: A Review

“…Proper image filtering will allow substantial dose reduction with preservation of or even increase in diagnostic image quality. 15,16 The use of iterative reconstructions has enabled a radiation-dose reduction with preserved image quality. 17 The radiation dose becomes larger as the number of acquisitions during 4D-CTA or the dose per acquisition is increased.…”

“…13,14,19 TI-CTA, on the other hand, was shown to have a 43% higher contrast-to-noise ratio and a 28% lower image noise compared with conventional CTA. 16 In addition, TI-CTA was rated as having less vascular noise, better vascular contour, better detail visibility of medium arteries, better detail visibility of small arteries, and better overall image quality than conventional CTA and 4D-CTA. 16 Choice of Acquisition Technique.…”

“…16 In addition, TI-CTA was rated as having less vascular noise, better vascular contour, better detail visibility of medium arteries, better detail visibility of small arteries, and better overall image quality than conventional CTA and 4D-CTA. 16 Choice of Acquisition Technique. The choice between a continuous or noncontinuous 4D-CTA acquisition depends on the available scanning modes and is limited to noncontinuous acquisitions in case of toggling-table or shuttle modes.…”

Strategies of Collateral Blood Flow Assessment in Ischemic Stroke: Prediction of the Follow-Up Infarct Volume in Conventional and Dynamic CTA

“…Dynamic angiographies were then represented as source images and temporal MIPs. Computation of temporal MIPs included a 4D noise reduction; our approach was previously described by Smit et al 20 We created 3 different temporal MIPs representing the arterial phase, the arteriovenous phase, and the venous phase, to determine differences in collateral vessel enhancement with time. We created temporal MIPs of the different phases rather than using source images acquired at a single time point, to optimize quality because temporal MIP computation included the aforementioned 4D noise reduction.…”

“…This process has been shown to increase the signal-tonoise ratio, vessel contour, detail visibility, and overall image quality. 20 For standardization and adjustment for interindividual differences in circulation times and bolus dispersion, we used the time point of peak contrast enhancement of the contralateral MCA to separate arterial and arteriovenous phases and the time point of peak contrast enhancement of the superior sagittal sinus to separate arteriovenous and venous phases (Fig 1).…”