Angiography, Digital Subtraction

Tips and Tricks


Avoiding Complications

Air Bubble

One of the complications of cerebral angiography is ischemic stroke caused by an injected air bubble (Case 4). There are several tips to avoid such a complication.



Left VA Injection - PA

There is a round hypodensity (arrow) that seems to be in the transverse segment of the left VA, worrisome for an air bubble. However, it did not travel forward as the run went on. Upon further examination, it represented the junction of the bilateral VBs and was caused by the dilution of the contrast due to the competitive flow from the right VA.


(A): This patient presented with a supraclinoid aneurysm, which appears to be an isolated aneurysm without an adjacent branch.
(B): After flow diverter embolization, the stasis of the contrast revealed a small adjacent superior hypophyseal artery (yellow arrow).

3 - Pixel Shift

This patient underwent mechanical thrombectomy under moderate sedation for acute right ICA terminus occlusion. DSA images were blurred due to head motions (A and C). After pixel shift (B and D), the image quality significantly improved.

4 - Air Bubble

An air bubble can be seen injected into the internal maxillary artery, fortunately without causing any significant clinical complications.


Left Column: PA Views; Right Column: Lateral Views

In this scenario, the goal was to super-select the green branch of the frontal division (black) of the middle meningeal artery (B). However, challenges arose due to anatomical constraints, including: 1. An acute angle at the origin of the target branch observed on PA views; 2. Limited diameter of the artery, impeding the manipulation of the microwire tip. As a workaround, the red branch was intentionally blocked using coils.

(A): The microwire was advanced into the red branch.
(B): Illustrative depiction of the arterial branches.
(C): Coil embolization of the red branch.
(D): Achievement of successful microwire advancement into the intended target branch subsequent to rebounding from the coils.

White arrow: Microwire tip.
Black arrow: The main trunk of the frontal division of the MMA.
Yellow arrow: Microcatheter tip.


After the deployment of the flow diverter stent, the subsequent procedure involves recapturing the delivery wire (orange arrow) utilizing the microcatheter (red arrow) to maintain intra-stent access (A). However, owing to the pressure accumulated during the stent delivery process, the mico-system tightly conforms to the arterial wall (white dotted line), hightening the risk of the microcatheter tip entanglement with the proximal stent. An effective maneuver to mitigate this risk involves "unloading"* the entire micro-system to diminish wall apposition (B). Note the advancement of the intermediate catheter (cyan arrow). Subsequently, delicately advancing the microcatheter while gradually withdrawing the microwire (C) facilitates the smooth advancement of the microcatheter into the stent without impending its integrity (D).

Yellow arrow: Recapture marker.
Blue arrow: Proximal marker.
*Unloading means systematic withdrawal of the microcatheter and accompanying microwire as an integrated system.