DSA / catheter angiography

Nuclear & X-ray · reads

Cerebral digital subtraction angiography is an invasive imaging method that uses ionizing radiation. A contrast dye is injected through a catheter in a large artery, and an image taken before the dye arrives is subtracted from the images that follow, leaving mainly the blood vessels visible. The sequence shows the dye filling the arteries, passing through the capillaries and draining through the veins, at a few frames per second in routine dose-limited practice and up to 60 frames per second in high-speed studies. What it reads is the transit of the dye, an indirect picture of brain blood flow and vascular malformations.

Spatial resolution

79 µm

Temporal resolution

16.7 ms (sample interval)

Field of view

1.23 L (acquired volume)

Reads

contrast-agent transit

Destructive?

minimally destructive

Prerequisites

surgery: Femoral access was predominant. Reported femoral equipment included 4F–5F sheaths with angled or sidewinder catheters and guidewires, or 5F–6F introducer sheaths; another protocol used a 5F sheath and primarily a 5F single-curve catheter.; surgery: For the described transradial protocol specifically, the right radial artery was punctured by the Seldinger method after 2% lidocaine; wire advancement was fluoroscopically observed, a 16-cm 6F hydrophilic sheath was inserted, and nitroglycerin, heparin, and verapamil were infused through it. Brachial access was also reported, without technical details.; contrast agent: Reported agents were manually injected non-ionic Solutrast 300 mg/mL and iopamidol.; anesthesia: One series used 1% lidocaine at the puncture site for all procedures. Conscious sedation was given only when necessary, using optional IV midazolam 1–2 mg and/or fentanyl 25–50 µg. General anesthesia was specified for spinal, not cerebral, angiography.

Theoretical temporal resolution

1 ms (sample interval)

Theoretical field of view

1.23 L (reachable envelope)

Description

Cerebral digital subtraction angiography (DSA) is an invasive imaging method that follows an injected contrast agent through the blood vessels of the brain using ionizing radiation. A catheter is advanced into a large artery and a contrast agent is injected through it; one centre's standard protocol uses transfemoral access, and transradial access has gained popularity as an alternative for interventional procedures. A mask image acquired before the contrast arrives is subtracted from the subsequent contrast-enhanced image series, so the images show the vasculature at the site of intervention without other anatomical structures. The sequence shows the contrast progressing from the large artery through smaller arteries and the capillaries, then out through the veins: high-resolution dynamic imaging of arterial filling and venous drainage. A 2021 report described best practice as routinely limiting frame rates to 1-3 frames per second to reduce radiation exposure, with up to 7.5 frames per second in some cases; high-speed clinical DSA has been acquired at 60 frames per second in patients with intracranial aneurysms. Color-coded parametric angiography (quantitative DSA) additionally builds a time-density curve from the same acquisition and extracts time- and attenuation-related parameters from it. What is imaged is the transit of the contrast agent, an indirect representation of cerebral blood flow and of vascular malformations.

Download the dataset (JSON, described by its JSON Schema).

Loading…