IV Flat Detector CT Angiography in Flat Detector CT Image-Guided Minimally Invasive Surgery for the Treatment of Intracerebral Hypertensive Hemorrhage

DISCUSSION

ICH accounts for 10%–40% of all strokes worldwide and is as high as 40% in Asia. The fatality and disability rate exceeds 60%, and the incidence is increasing year by year. Possible treatments of ICH include¹ conservative medical treatment for hemostasis and coagulopathy or² surgical treatment to remove the hematoma. Whether surgery can improve the prognosis of patients with ICH remains controversial. The Surgical Treatment for Ischemic Heart Failure (STICH) and STICH II trials aimed to investigate the effectiveness of early surgery (mostly craniotomy) compared with initial medical treatment alone, and the results were neutral. However, the question about the performance of less invasive surgery to remove ICH was raised. The randomized controlled Minimally Invasive Surgery Plus Rt-PA for ICH Evacuation (MISTIE)⁴ II study demonstrated the safety and efficacy of alteplase in combination with MIS in ICH management. The MISTIE III trial compared the image-guided MISTIE treatment with standard medical care, but no improvement was found in the functional outcome at 365 days.⁵ However, in the subgroup study in which ICH volume was reduced to ≤15 mL or was >70%, better mRS scores could be achieved. This finding indicates the importance of surgery efficiency in determining good functional outcome of MIS in ICH evacuation.⁶

The effectiveness of hematoma evacuation is heavily dependent on the decreased hematoma volume. According to our experience, the hematoma may contain a mixture of liquid, semisolid, and solid material throughout the evacuation procedure, making it impossible to reduce the volume equally. Accurate catheter placement with as much contact area as possible with the hematoma and intraoperative real-time monitoring are essential to ensure the safety and effectiveness of hematoma evacuation and avoid unintentional loss of brain tissue. The angiography system with intraoperative FDCT imaging of the brain parenchyma to assess the degree of ICH evacuation has been described before, and the needle guidance software enables precise catheter placement and navigation accuracy, in which puncture path planning is realized on intraoperative FDCT 3D volume images by identifying the target hematoma and the entry point on the skull. A virtual flight along the needle path can be checked in 3 MPR (Multiplanar Reformation) segments to verify that the needle path does not injure any anatomic structure, and the laser positioner light is automatically on and indicates the entry point on the skull.^9,10,18

Minimally invasive craniopuncture using a YL-1 needle via a temporal approach has become a standard surgical method commonly used in China. It has shown the advantages of a small deviation, low cost, and low surgical difficulty with good functional outcomes through multiple randomized clinical trials, making it a practical and promising technique for ICH clot removal, especially in primary hospitals with large patient populations.^19⇓⇓-22 Compared with conventional CT-guided stereotactic aspiration, craniopuncture under the guidance of FDCT in an interventional operating room has become more suitable due to better environment hygiene and emergency event responses. However, it can be challenging to securely avoid the external carotid artery and major vessels of the lateral fissure when using a temporal approach. Prior research did not include cerebral vascular information in craniopuncture; the authors used noncontrast FDCT solely for planning and guidance.^9,10,18

In this study, we first introduced ivFDCTA into the hematoma-evacuation workflow. All the arteries of the brain can be seen due to the IV-injection acquisition protocol, which could be used for puncture needle path planning to prevent secondary bleeding. In previous studies, the rebleeding rate of minimally invasive brain puncture under CT was 8.8% to 10%.²³ Chen et al²⁴ reported a study of 48 patients with ICH treated with the YL-1 needle under CT guidance; 2 of these cases required repositioning the puncture needle due to inadequate initial placement. Three (6.3%) patients experienced early re-bleeding within the first 3 postoperative days, a rate higher than in our study. The 6-second ivFDCTA protocol is substantially faster than the 20-second previously reported protocol, but it provides adequate image quality for hematoma identification, reducing the radiation exposure and accelerating the preparation for the procedure. As shown in Fig 1, during puncture planning, both blood vessels and hematoma could be observed by displaying the ivFDCTA native and contrast-enhanced images, allowing the physician to plan the needle path safely and more accurately to avoid large vessels and reduce intraoperative bleeding and complications. In case of a large hematoma, it may be difficult to achieve the target of volume reduction with a single puncture, and multiple target points may be needed.²⁵ Marquardt et al²⁶ demonstrated the safety and efficiency of multiple target aspiration techniques. Zhou et al²⁰ compared 80 patients with HICH who received CT-guided MIS and showed that the clearance rate of hematomas in patients with hematomas of >40 mL with a single puncture was less than in those with multiple punctures. With the ivFDCTA in ICH removal, the large vessels on the puncture tract can be accurately visualized and located, and intraoperative CT enables multiple punctures performed safely and sterilely in the interventional operating room (Fig 2).

Because it is reliable and convenient, minimally invasive puncture has been widely used in China to treat HICH. The 2 most commonly used puncture needles are the soft tube, also called the “soft channel” approach, and the YL-1 puncture needle, also known as the “hard-channel” technique. Comparisons between the 2 methods are rare, yet available. In a study involving 150 patients, Xia et al²² found that there was no discernible difference in the amount of hematoma and perihematomal edema on day 7 between the 2 techniques. The benefits of the soft tube tend to be ease of direction adjustment and quick rinsing. We chose the hard channel because it allows us to fully use intraoperative FDCT while enabling safe adjustments outside the dura and accurate placement at the assigned position using the skull-fixation technique. If the first puncture volume reduction is not satisfactory, multiple punctures can be performed in a sterile state. On the contrary, due to the presence of the C-arm, the operating space directly above the head during soft-channel puncture will be affected.ivFDCTA is a technique to generate CTA-like images using DSA through noninvasive IV contrast media injection. In the field of neurology, this technique was first proposed as a noninvasive alternative for follow-up after placement of intracranial devices such as stents and flow diverters and enabled good visualization of both the device and vessel lumen.^15⇓-17 ivFDCTA also shows comparable image quality with 2D and 3D DSA in delineating and diagnosing vessel stenosis and aneurysms, and even better quality in visualizing complex aneurysms.^12⇓-14 In the ICH evacuation procedure, we also found that ivFDCTA has the potential to be used for a rapid screening of the cerebral vasculature malformations to avoid secondary bleeding during the evacuation procedure. According to the guideline for ICH management, CTA is recommended for detection of some structural causes of secondary ICH and signs of hematoma expansion.²⁷ However, patients with ICH, especially in those with a high NHISS score, often have severe agitation and require sedation to undergo a CTA scan. Nevertheless, a standard anesthesia procedure and care management are not available due to limited space and equipment resources in the CT room. Most CT examination rooms lack sufficient first aid and patient-monitoring equipment to handle emergencies, and patient risks may increase during suite transfers. Furthermore, bone artifacts and spatial resolution may restrict the precision of CTA-based vascular malformation diagnosis and geometric delineation. In addition to generating 2D cross-sectional images, the ivFDCTA methodology we describe in this article could also generate IV 3D DSA (Fig 4), which provides a volumetric view of the cerebral arteries and enables determination of the optimal C-arm working angle if intraoperative endovascular treatment is necessary. Therefore, with the use of ivFDCTA, clinical steps including screening for cerebrovascular disease, puncture needle path planning and navigation, hematoma evacuation, and endovascular treatment could all be performed in the angiography suite. This one-stop cerebral hemorrhage management workflow has the potential to eliminate the treatment delays and risks during transfer and increase the safety of the procedure and the efficiency of hematoma evacuation.

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FIG 4.

IV 3D DSA image.

Our study has limitations. First, this is a retrospective single-center study. The amount of patient data collected is small and requires further research and the completion of statistical analyses of long-term neurologic outcomes. Second, there is no comparison group in this study. Comparison between FDCT and ivFDCTA guidance will be included to further explore the clinical value of ivFDCT in ICH management. Third, the initial calculation of the hematoma volume according to the Tada formula (Hematoma Amount = Long Diameter of the Largest Level of Hematoma × Short Diameter of the Largest Level of Hematoma × Number of Levels of Hematoma × π/6) is based on the principle that the bleeding focus is assumed to be an elliptic sphere, which has evolved from the formula for calculating the volume of an elliptic sphere. For the irregular shape of a hematoma, the calculation error is large and the calculated volume is often larger than the actual volume of the hematoma. Another more accurate hematoma calculation method needs to be adopted.