Parent Vessel Patency Research Articles

Comparison of the imaging performance of time-of-flight MRA and ultrashort echo time MRA in flow diverters: A phantom study

Objective Flow diverters (FD) are innovative treatments for wide-neck intracranial aneurysms. After-treatment verification of embolization and parent vessel patency is crucial. While evaluation using time-of-flight magnetic resonance angiography (TOF-MRA) is useful, it suffers from signal loss within the FD due to susceptibility effects. This study evaluates the usefulness of ultrashort echo time MRA (UTE-MRA) for after-FD assessment compared to TOF-MRA. Methods Vascular phantom experiments were conducted using FDs (FRED®, Pipeline®, Surpass Streamline®). TOF-MRA and UTE-MRA were performed under steady (10, 30, 50 cm/s) and pulsatile (17–61 cm/s, mean 34 cm/s) flow conditions using a 3 T MRI system. As evaluation metrics, relative in-FD signal (RIS) was calculated by comparing the signal intensity inside the FD to that without the FD to assess signal retention, and FD luminal to background signal ratio (FD-LBR) was calculated by comparing the signal intensity inside the FD to that of the surrounding background to evaluate vessel visibility. Results UTE-MRA showed higher FD-LBR values than TOF-MRA for all FDs ( p < 0.01). For RIS, UTE-MRA was significantly higher for FRED® ( p < 0.01), but different for other FDs except at 50 cm/s. FRED® exhibited the highest RIS and FD-LBR values under all conditions, followed by Pipeline® and Surpass Streamline®. Flow velocity changes resulted in minimal variations in RIS and FD-LBR values. Conclusion UTE-MRA provides superior image quality for after-FD assessment, particularly in terms of FD-LBR, compared to TOF-MRA. Differences in FD materials and structures affect image quality. These findings suggest UTE-MRA's clinical utility in follow-up after-FD assessment.

Angiographic Safety and Efficacy of the ReSolv Flow-Diverting Stent in a Rabbit Model.

Bioresorbable polymer-based flow-diverting stents have potential benefits over existing metal devices. This study aimed to evaluate the safety and efficacy of the novel ReSolv device, which is a primarily polymer-based flow-diverting stent, using the in vivo rabbit sidewall saccular aneurysm model. ReSolv stents were deployed in 14 New Zealand White rabbits that had undergone aneurysm creation procedures. Animals were allocated to follow-up time points of 1, 3, 6, 9, 12, 16, or 18 months. Angiographic images were evaluated by an independent neurointerventionalist blinded to follow-up time points for (1) in-stent stenosis, (2) parent vessel and jailed side branch patency, (3) wall apposition, and (4) aneurysm occlusion using the Raymond-Roy Occlusion Classification (RROC), O'Kelly Marotta grading scale, and the 4F flow diversion predictive score. Primary efficacy outcome was defined as RROC Class I or II. At a median follow-up time of 7.5 months, parent vessel (14/14) and jailed side (33/33) branches were patent in all cases. There was no development of thrombus on the stent or cases of significant in-stent stenosis, and all stents had good wall apposition. Adequate occlusion was found in 85.7% (n = 12) of animals, including an RROC Class I in 64.3% (n = 9) and RROC Class II in 21.4% (n = 3). The ReSolv stent shows encouraging angiographic safety and efficacy outcomes after placement in a rabbit sidewall saccular aneurysm model. Longer term studies are ongoing to determine eventual fate of the aneurysm, parent vessel, and jailed side branches after absorption of the polymer component of the stent.

Long-term follow up of surgical management of blood blister-like aneurysms at non-branching sites of the internal carotid artery.

To describe long-term follow-up of 25 patients who presented with subarachnoid hemorrhages due to blood blister-like aneurysms (BBAs) treated with direct clipping or clip reinforcement with or without direct neck repair. Between June 1993 and July 2009, 25 consecutive patients with ruptured BBAs of the supraclinoid internal carotid artery were retrospectively reviewed. The mean age of patients was 39.5 ± 11.3 years. The mean duration of clinical follow-up was 128.9 months (range, 85-196 months). All aneurysms were located in the supraclinoid portion of the internal carotid artery. The mean aneurysm diameter was 4.04 ± 1.3 mm on intra-operative microscopic field. Tearing of the aneurysmal neck during dissection occurred in 8 (32%) patients. Six of 7 patients with neck tearing underwent direct neck repair. Surgeons treated aneurysms via direct clipping with a Bemsheet® in 5 (20%) patients or by clip reinforcement with a silicone sheet in 20 (80%) patients. Clinical outcomes were favorable (modified Rankin Scale [mRS]: 0-2) in 21 (84%) of 25 patients. Four (16%) patients had an unfavorable outcome (mRS: 3-6). The patient with severe disability (mRS: 4) was treated with clip reinforcement and direct neck repair. Mild stenosis, moderate stenosis, and total occlusion of the parent artery were confirmed in 10 (40%) patients, 6 (24%) patients, and 1 (4%) patient, respectively. Although surgical treatment of BBAs was associated with varying degrees of parent vessel patency loss, long-term follow-up results for more than 10 years showed that direct surgical clipping or clip reinforcement with a silicone sheet appeared to be a curative surgery.

Intraoperative Angiogram Using C-Arm Fluoroscopy and Direct Common Carotid Artery Puncture During Surgical Treatment of Paraclinoid Aneurysms

Intraoperative angiography (IOA) has been shown to be a useful adjunct in surgical treatment of cerebral aneurysms. However, its use can be limited by hybrid operating room availability. On the other hand, the use of C-arm fluoroscopy can add challenges to IOA during navigation of the aortic arch and selection of the great vessels. We aimed to describe a simple method of IOA that can be applied during surgery of paraclinoid aneurysms and can be performed in a normal operating room without the need to navigate the aortic arch. In patients undergoing surgery for paraclinoid aneurysms with need for cervical carotid artery exposure, IOA was performed using a single plane C-arm fluoroscopy unit after direct puncture of the carotid artery. Five patients were included: 2 with subarachnoid hemorrhage, 2 with unruptured aneurysm and history of subarachnoid hemorrhage, and 1 with unruptured aneurysm. There were 2 internal carotid blister aneurysms, 2 ophthalmic artery aneurysms, and 1 superior hypophyseal artery aneurysm. IOA was performed using direct carotid puncture through the neck incision required for proximal control. In all cases, intraoperative images were of sufficient quality to determine the completeness of aneurysm occlusion as well as parent and branching vessel patency. There were no postoperative infarctions and no complications related to IOA. IOA using direct carotid puncture can be performed in a standard operating room with the use of a C-arm, eliminating the need to catheterize the great vessels of the aortic arch.

Comparison between Digital Subtraction Angiography and Indocyanine Green Video Angiography in the Operative Management of Aneurysmal Subarachnoid Hemorrhage

Abstract Background Digital subtraction angiography (DSA) is a fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment. Images are produced using contrast medium by subtracting a “pre-contrast image” or mask from subsequent images, once the contrast medium has been introduced into a structure, hence the term “Digital subtraction angiography.” Indocyanine green video angiography (ICG-VA) is a safe and practical method of real-time delineation of microvasculature used in the surgical management of intracranial aneurysms, arteriovenous malformations, and other vascular lesions. Intraoperative ICG-VA is used as an adjunct in addition to intraoperative or postoperative DSA, and in other cases, it is used as the sole method to confirm the complete obliteration of clipped intracranial aneurysm. The only limitation of ICG-VA is the nonvisibility of vessels that are not in the operative field. Intraoperative ICG is useful in the clipping of intracranial aneurysms to ensure a gross patency of branch vessels; however, the presence of residual aneurysms and subtle changes in flow in branch vessels is best seen by DSA. Methods ICG angiography was done during the surgery and the findings of intraoperative ICG angiography were compared with postoperative DSA that was done between 6 and 12 weeks. DSA was done to see any compromise of lumen of parent vessel by clip, any residual aneurysm. Results In our study, intraoperative ICG complete aneurysm obliteration was present in all 30 (100%) patients, while in postoperative DSA complete aneurysm obliteration was diagnosed in 27 (90.0%) patients. Parent vessel patency was present in all 30 (100.0%) patients in both intraoperative ICG-VA and postoperative DSA. In intraoperative ICG distal branch patency was present in 26 (86.7%) patients, while in postoperative DSA distal branch patency was diagnosed in 27 (90.0%) patients. Conclusion We compared the intraoperative ICG finding and postoperative DSA finding and found that DSA is more sensitive than ICG in depicting residual aneurysm neck, hence reducing the risk of rupture of the aneurysm in future. Intraoperative ICG has high special resolution reflex feedback, intraoperative repositioning time is less and thus critical ischemia time is reduced. In a developing country like ours where DSA facilities are limited, ICG can be optimal investigation to delineate the vascular anatomy and confirmation of clip position thus reducing mortality.

Multiple intra-aneurysmal WEB devices: Case discussions and operative technique

The Woven Endobridge (WEB, Sequent Medical, Aliso Viejo, California) device has emerged as an FDA approved endosaccular flow diverting alternative for patients with complex aneurysm morphology. We describe for the first time, in patients with dual anti platelet therapy (DAPT) non compliance, two cases during which multiple WEB devices were deployed within the aneurysm sac to achieve flow disruption. Two ophthalmic segment internal carotid artery aneurysms are treated by the deployment of an additional WEB device within the sac. We subsequently discuss the techniques utilized to ensure parent vessel patency. We demonstrate that patients with contraindications to endovascular modalities requiring DAPT may be candidates for a multi WEB intra-aneurysmal construct.

"Reverse Picket Fence" Technique for Clipping of a Large, Anterior Communicating Artery Aneurysm: 2-Dimensional Operative Video.

The "picket fence" technique is a clipping technique used for large, wide-neck complex aneurysms not suitable for conventional clipping.1 With this technique, simple or fenestrated straight clips are stacked side-by-side perpendicular to the neck rather than the conventional parallel placement. In complex aneurysms projecting away from the surgeon, the picket fence technique is impossible. Instead, fenestrated clips are applied in a reverse direction from neck-to-dome, using the blade heels to close the neck. This fenestration tube transmits the bifurcation. This video demonstrates a "reverse picket fence" clipping technique of an incidental, large anterior communicating artery (ACoA) aneurysm in a 52-yr-old woman. Bilaterally adherent A2-anterior cerebral artery (ACA) segments led to abortion of a prior clipping attempt at an outside hospital. After obtaining patient consent, a modified orbitozygomatic craniotomy was performed with gyrus rectus removal. Temporary clips were applied to A1-ACA for freeing the adherent A2-ACA segments from the dome. The aneurysm was clipped using a "reverse picket fence" technique transmitting the A1-A2-A2 bifurcation through the fenestration tube. Bilateral recurrent artery of Heubner was preserved. Indocyanine angiography demonstrated parent vessel patency with complete aneurysm exclusion. Postoperatively, the patient experienced short-term memory loss, which resolved over 6 mo with cognitive rehabilitation. The "reverse picket fence" technique can be considered for large aneurysms directed away from the surgeon, obviating the need for difficult dissection of adherent efferent arteries from aneurysmal sac. Adjusting the heel position of each fenestrated clip in this construct allows the patency of hidden perforators behind the aneurysm to be maintained. Video © Barrow Neurological Institute. Used with permission.

Orbitozygomatic Craniotomy for Clipping a Complex Middle Cerebral Artery Aneurysm: 2-Dimensional Operative Video.

Middle cerebral artery (MCA) aneurysms pose a surgical challenge because of the large caliber of the parent artery and the common need to dissect the sylvian fissure to permit access to the proximal and distal control. The neck of the aneurysm should be generously dissected to permit visualization of any adjacent lenticulostriate perforators. This patient demonstrated a left-sided wide-necked bilobed MCA aneurysm at the M1 bifurcation. The aneurysm was approached using a left orbitozygomatic craniotomy with distal sylvian fissure dissection. A single curved clip was applied for aneurysm occlusion, and postoperative angiography demonstrated aneurysm obliteration with parent vessel patency. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Orbitozygomatic Craniotomy for Giant Anterior Communicating Artery Aneurysm: 2-Dimensional Operative Video.

Giant intracranial aneurysms pose a significant surgical challenge because of the associated difficulty in achieving adequate visualization of the parent artery and aneurysm neck. This patient had an incidentally identified giant anterior communicating artery aneurysm. An orbitozygomatic craniotomy was performed for aneurysm exposure and aneurysmal neck dissection. Aneurysm dome opening and thrombectomy was performed to debulk the aneurysmal mass, which facilitated subsequent aneurysmal neck visualization. Sequential utilization of temporary clips of the bilateral A1 and bilateral A2 vessels reduced hemorrhage during thrombectomy. Multiple permanent clips were applied along the dissected aneurysm neck to permit occlusion. A small fracture of the aneurysm neck was identified, and cotton was applied with subsequent tamponade utilizing a fenestrated clip to maintain hemostasis. Indocyanine green fluoroscopy was used to verify parent and distant vessel patency. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Safety and Feasibility Assessment of the O-Arm as an Intraoperative Angiography Device in Aneurysm Surgery

To describe the technique and initial experience of using a rotational 3-dimensional (3D) fluoroscopy system (O-arm; Medtronic) as intraoperative angiography (IA) in the surgery of cerebral aneurysms. The 3D IA with O-arm (IAWOA) was performed in a consecutive cohort of patients with unruptured intracranial aneurysms. Conventional microsurgical clipping was performed with the assistance of indocyanine green videoangiography. Then the O-arm chassis was brought in, the ipsilateral internal carotid artery was catheterized, and contrasted images were acquired. Resulting datasets were exported in Digital Imaging and Communications in Medicine and processed using the Osirix software in an accessory computer. The 3D image reconstruction was evaluated intraoperatively to confirm aneurysm occlusion and parent vessel patency. Afterward, agreement among IAWOA, indocyanine green videoangiography, and standard postoperative angiography was analyzed. The initial pilot study was performed in 6 patients with 7 unruptured aneurysms. The aneurysm occlusion rate was 100%. The concordance of the IAWOA and the standard postoperative angiography was complete, both in terms of occlusion and parent vessel patency. No complications derived from the IAWOA were observed except in 1 patient, who presented a retroperitoneal hematoma without clinical consequences. The 3D rotational fluoroscopy (O-arm) device could be safely and effectively used as an IA system in selected patients. To the best of our knowledge, this is the first study reporting its use as an IA device. This technique seems to offer excellent image quality that could be compared with that of the gold standard 3D digital subtraction angiography but with a lower cost and versatility of use for other subspecialties.

Endovascular Treatment of Posterior Inferior Cerebellar Artery Aneurysms with Flow Diversion.

Flow diversion is a viable alternative for treatment of wide-neck and fusiform aneurysms originating from the posterior inferior cerebellar artery (PICA), but coverage of the PICA and vertebral perforating arteries may be a concern. The aim of this study was to examine procedural, clinical, and angiographic outcomes of patients with PICA aneurysms treated with the Pipeline Embolization Device. Retrospective review was performed of PICA aneurysms treated with the Pipeline device at 3 neurovascular centers, including periprocedural complications and clinical and angiographic outcomes. In 16 procedures, 14 PICA aneurysms were treated with the Pipeline device. These included 11 saccular aneurysms with a mean size of 7.4 mm (range, 2.0-11.1 mm) and 3 fusiform aneurysms with a mean diameter of 6.1 mm (range, 5.0-8.0 mm) and mean length of 10.3 mm (range, 6.0-15.0 mm). One patient developed a PICA territory infarct with mild leg weakness that resolved in <7 days. Overall complication rate was 7% (1/14) per patient and 6% (1/16) per procedure. Mean duration of clinical follow-up was 13.5 months (range, 3 weeks to 61.7 months), with all patients returning to baseline functional status. Complete or near-complete aneurysm occlusion was achieved in 58% (7/12) of cases with angiographic follow-up (mean, 15 months; range, 4-61 months). All covered PICAs remained patent. Flow diversion of PICA aneurysms is a safe and viable treatment option when traditional endovascular options are unlikely to preserve parent vessel patency.

Dual- versus Single-Energy CT-Angiography Imaging for Patients Undergoing Intracranial Aneurysm Repair

Background: The invasiveness and risk of thromboembolic complications of catheter angiography underline the need for alternative imaging modalities in patients following intracranial aneurysm (IA) repair. However, the overall image quality of existing noninvasive imaging modalities, such as single-energy CT angiography (SE-CTA), compromises its value in this respect. Objective: We prospectively investigated the value of a novel dual-energy CTA (DE-CTA) scanner and algorithm for assessing the degree of occlusion and parent vessel patency in patients following IA repair. Methods: A prospective cohort of 17 patients underwent DE-CTA imaging following surgical or endovascular IA repair. This dataset was matched with an identical historical cohort of 17 patients, who underwent IA repair and SE-CTA imaging. Beam-hardening artifacts, as a measure for objective imaging quality were analyzed based on the volume of a prolate ellipsoid, whereas subjective imaging quality at the IA site and corresponding parent vessels was rated by 2 independent neuroradiologists on a scale from 4 (excellent, no artifacts) to 1 (poor, severe artifacts). Results: Objective DE-CTA image quality was markedly higher, compared to SE-CTA in patients undergoing surgical (0.77 ± 0.23 vs. 10.91 ± 1.88 mL, respectively; p < 0.001) or endovascular (32.36 ± 10.62 vs. 107.63 ± 24.51 mL, respectively; p = 0.026) IA repair. Subjective image quality for DE-CTA was significantly improved compared to SE-CTA in the surgical group but not in the endovascular group. The calculated dose values for DE-CTA in our study remain markedly below the legally required radiation dose limits. Conclusion: The imaging quality of DE-CTA, especially for patients undergoing surgical IA repair, is distinctly superior, compared to SE-CTA imaging. Therefore, DE-CTA may serve as a noninvasive alternative for assessing the IA occlusion rate and parent vessel patency.

The only case of mycotic aneurysm of the PICA: Clinical-radiological remarks and review of literature

We present the first and only case, reported in literature, of a 67-years-old man with a mycotic aneurysm (MA) of the left posterior inferior cerebellar artery (PICA), caused by group B Streptococcus, that we surgically treated, performing neck aneurysm clipping, preserving patency of parent vessel. Moreover the peculiarity of this case is represented by the fact that the MA is originated from a tooth abscess, treated about two years before. To date, there have been only 10 cases of association between MA with either tooth pathologies or dental surgical procedures and our case is the only one originating from PICA. Therefore an extensive literature analysis was performed. Hence if we observe a patient with a fusiform aneurysm in posterior intracranial circulation and clinical history of fever and/or persistent neck swelling after dental pathologies, it is mandatory to consider the possibility of a MA, for a correct differential diagnosis. If the diagnosis is confirmed, it is necessary to research the origin of infection and to set the specific antibiotics therapy.

Blister-Like Aneurysms: Report of Successful Surgical Treatment of Consecutive Cases and Review of the Literature

Blister-like aneurysms (BAs) are usually defined as arterial lesions arising from nonbranching sites on intracranial arteries. Because of specific peculiarities such as different pathophysiology, fragility of the aneurysmal wall, high risk of intraoperative bleeding, and high probability of losing parent vessel patency, their treatment is controversial, and both endovascular and surgical options have been reported. From 2006 to 2015 (10 years), 7 aneurysms in 6 patients were treated. We retrospectively reviewed the records of these patients to analyze clinical pictures and outcomes, which are expressed as modified Rankin Score. In our sample of 7 aneurysms in 6 patients, all BAs were successfully treated (complete exclusion in 100% on follow-up angiography). A good outcome (modified Rankin Score= 0) was achieved in all patients, with no difference related to aneurysm size and location. There was no mortality. Surgical treatment of BAs may be effective and have acceptable complications and outcomes.

Meningocele and Meningoencephalocele of the Lateral Wall of the Sphenoid Sinus

Blister-like aneurysms (BAs) are usually defined as arterial lesions arising from nonbranching sites on intracranial arteries. Because of specific peculiarities such as different pathophysiology, fragility of the aneurysmal wall, high risk of intraoperative bleeding, and high probability of losing parent vessel patency, their treatment is controversial, and both endovascular and surgical options have been reported.From 2006 to 2015 (10 years), 7 aneurysms in 6 patients were treated. We retrospectively reviewed the records of these patients to analyze clinical pictures and outcomes, which are expressed as modified Rankin Score.In our sample of 7 aneurysms in 6 patients, all BAs were successfully treated (complete exclusion in 100% on follow-up angiography). A good outcome (modified Rankin Score = 0) was achieved in all patients, with no difference related to aneurysm size and location. There was no mortality.Surgical treatment of BAs may be effective and have acceptable complications and outcomes.

Metal artifact reduction for flat panel detector intravenous CT angiography in patients with intracranial metallic implants after endovascular and surgical treatment

BackgroundFlat panel detector CT angiography with intravenous contrast agent injection (IV CTA) allows high-resolution imaging of cerebrovascular structures. Artifacts caused by metallic implants like platinum coils or clips lead to...

Minimally Invasive Monitoring of Chronic Central Venous Catheter Patency in Mice Using Digital Subtraction Angiography (DSA).

BackgroundRepetitive administration of medication or contrast agents is frequently performed in mice. The introduction of vascular access mini-ports (VAMP) for mice allows long-term vascular catheterization, hereby eliminating the need for repeated vessel puncture. With catheter occlusion being the most commonly reported complication of chronic jugular vein catheterization, we tested whether digital subtraction angiography (DSA) can be utilized to evaluate VAMP patency in mice.MethodsTwenty-three mice underwent catheterization of the jugular vein and subcutaneous implantation of a VAMP. The VAMP was flushed every second day with 50 μL of heparinized saline solution (25 IU/ml). DSA was performed during injection of 100 μL of an iodine based contrast agent using an industrial X-ray inspection system intraoperatively, as well as 7±2 and 14±2 days post implantation.ResultsDSA allowed localization of catheter tip position, to rule out dislocation, kinking or occlusion of a microcatheter, and to evaluate parent vessel patency. In addition, we observed different ante- and retrograde collateral flow patterns in case of jugular vein occlusion. More exactly, 30% of animals showed parent vessel occlusion after 7±2 days in our setting. At this time point, nevertheless, all VAMPs verified intravascular contrast administration. After 14±2 days, intravascular contrast injection was verified in 70% of the implanted VAMPs, whereas at this point of time 5 animals had died or were sacrificed and in 2 mice parent vessel occlusion hampered intravascular contrast injection. Notably, no occlusion of the catheter itself was observed.ConclusionFrom our observations we conclude DSA to be a fast and valuable minimally invasive tool for investigation of catheter and parent vessel patency and for anatomical studies of collateral blood flow in animals as small as mice.

Stent-assisted coil embolization of a symptomatic middle cerebral artery aneurysm in an infant.

Pediatric intracranial aneurysms are rare and challenging to treat. Achieving efficacy and durability of aneurysmal occlusion while maintaining parent vessel patency requires innovative treatment strategies, especially in cases in which aneurysmal location or morphology pose substantial morbidity associated with microsurgical treatment. In the last 3 decades, endovascular treatments have had a remarkable evolution and are currently considered safe and effective therapeutic options for cerebral aneurysms. While endovascular techniques are well described in the English literature, the endovascular management of pediatric aneurysms continues to pose a challenge. In this report, the authors describe the case of a 9-month-old infant who presented with a 1-day history of acute-onset left-sided hemiparesis and left facial droop. Imaging revealed a large symptomatic saccular middle cerebral artery aneurysm. Treatment included successful stent-assisted aneurysm coiling. At follow-up, the patient continued to fare well and MR angiography confirmed complete occlusion of the aneurysm dome. This case features the youngest patient in the English literature to harbor an intracranial aneurysm successfully treated with stent-assisted coiling. Based on this experience, endovascular intervention with vascular reconstruction can be safe and effective for the treatment of infants and could further improve prognosis; however, further studies are necessary to confirm these findings.

Perspectives: Has Intraoperative Near Infrared Indocyanine Green Video-angiography Replaced Formal Angiography in Aneurysm Surgery?

ll technologic advancements in medicine aim to replace existing instruments with better, cheaper, or more userA friendly tools. More recent examples of such advancements have been widespread in endovascular neurosurgery. However, these technologic improvements, although more common in interventional procedures, have not been isolated to the endovascular realm. The use of near infrared indocyanine green video-angiography (ICGA), first described in 2003 by Raabe et al. (6), has gained widespread acceptance by many vascular neurosurgeons during aneurysm clipping. With a simple application of a modified digital recorder in the surgical microscope, near infrared video-angiography can detect intracranial vascular flow after intravenous injection of indocyanine green in an inexpensive, reliable, and safe manner. In many centers, ICGA has replaced intraoperative angiography because of the cumbersome, time-consuming, expensive, and potentially dangerous nature of intraoperative angiography. However, ICGA remains inferior to postoperative confirmatory angiography in complete evaluation of aneurysm occlusion and parent vessel patency. Over the past 10 years, many studies have been performed in an attempt to quantify when and how ICGA fails to measure up to postoperative angiography. Most of these studies have been underpowered single-center retrospective studies of a nonstandardized use of ICGA, leaving little ability to make any firm claim on specific shortcomings of the technology.

Predicting parent vessel patency and treatment durability: a proposed grading scheme for the immediate angiographic results following Onyx HD-500 embolization of intracranial aneurysms

IntroductionOnyx HD-500 embolization of intracranial aneurysms leads to high rates of complete and durable occlusion. However, little information exists as to what constitutes an optimal immediate angiographic result. We devised...