Risk Factors for Distal Clot Migration during Mechanical Thrombectomy of Anterior Circulation Large Vessel Occlusion.

INTRODUCTION: Distal clot migration (DCM) is a known complication of mechanical thrombectomy (MT), but neither risk factors for DCM nor ways of how it might affect clinical outcomes have been extensively studied to date. METHODS: To identify risk factors for and outcomes in the setting of DCM, the records of all patients with acute ischemic stroke due to anterior circulation large vessel occlusion (LVO) treated with MT at a single center between May 2016 and June 2018 were retrospectively reviewed. Uni- and multivariable analyses were performed to evaluate predictors of DCM and good functional outcome (90-day modified Rankin Scale; mRS 0-2). RESULTS: A total of 65 patients were included, DCM was identified in 22 patients (33.8%). Patients with DCM had significantly higher pre-procedural intravenous tissue plasminogen activator (IV-tPA) administration (81.8 vs. 53.5%, p = 0.03), stentrievers thrombectomy (95.5 vs. 62.8%, p = 0.006), and longer median puncture to recanalization time (44 [34-97] vs. 30 [20-56] min, p = 0.028) as compared to group with non-DCM. Also, they had lower rates of Thrombolysis in Cerebral Infarction (TICI) 2b/3 recanalization (p = 0.002), higher median National Institutes of Health Stroke Scale (NIHSS) scores at discharge (p = 0.01), and lower rates of 90-day mRS (0-2; 18.2 vs. 48.8%; p = 0.016). On subgroup analysis, patients with middle cerebral artery occlusions who underwent MT with stentrievers <40 mm in length had a higher risk of DCM (p = 0.026). On multivariable analysis, IV-tPA administration (OR; 5.019, 95% CI [1.319-19.102], p = 0.018) and stentrievers thrombectomy (OR; 10.031, 95% CI [1.090-92.344]; p = 0.04) remained significant predictors of DCM. Baseline NIHSS score (OR; 0.872, 95% CI [0.788-0.965], p = 0.008) and DCM (OR; 0.250, 95% CI [0.075-0.866], p = 0.03) were independent predictors of 90-day mRS 0-2. CONCLUSION: In patients undergoing MT for anterior circulation LVO, DCM is associated with lower rates of TICI 2b/3 recanalization and worse functional outcomes at 90 days. IV-tPA administration and MT with short stentrievers are independent predictors of DCM development.

Transradial flow diversion with an aberrant right subclavian artery.

Transradial access for diagnostic and therapeutic neurointerventional procedures has gained popularity due to a decreased incidence of access site complications and improved patient comfort compared with transfemoral access.1-4 An aberrant right subclavian artery is an aortic arch variant characterized by a right subclavian artery that arises directly from the arch as the most distal great vessel. Transradial access with an aberrant right subclavian artery is anatomically challenging due to the predilection of the catheter system to collapse into the descending aorta. In this (video 1), we describe a step-by-step technique for transradial access in a patient with an aberrant right subclavian artery undergoing endovascular flow diversion for a left superior hypophyseal artery aneurysm. Particular emphasis is placed on the technique for accessing the proximal arch and aortic valve as well as distal catheter navigation while avoiding prolapse into the descending aorta. neurintsurg;15/11/1164/V1F1V1Video 1 .

A persistent trigeminal artery demonstrates cerebrovascular embryologic development.

Background: Cerebrovascular embryologic development is characterized by the presence of four well-described carotid-vertebrobasilar (VB) anastomoses. As the fetal hindbrain matures and the VB system develops, these connections involute, yet some may persist into adulthood. The persistent primitive trigeminal artery (PPTA) is the most common of these anastomoses. In this report, we describe a unique variant of the PPTA and a four-way division of the VB circulation. Case Description: A female in her 70s presented with a Fisher Grade 4 subarachnoid hemorrhage. Catheter angiography revealed a fetal origin of the left posterior cerebral artery (PCA) giving rise to a left P2 aneurysm which was coiled. A PPTA arose from the left internal carotid artery and supplied the distal basilar artery (BA) including the superior cerebellar arteries bilaterally and the right but not left PCA. The mid-BA was atretic and the anterior inferior cerebellar artery-posterior inferior cerebellar artery complexes were fed solely from the right vertebral artery. Conclusion: Our patient's cerebrovascular anatomy represents a unique variant of the PPTA not well described in the literature. This demonstrates how hemodynamic capture of the distal VB territory by a PPTA is sufficient to prevent fusion of the BA.

Preoperative embolization of brain arteriovenous malformation and efficacy in intraoperative blood loss reduction: a quantitative study.

BACKGROUND: Embolization of brain arteriovenous malformations (bAVMs) is often used as adjuvant therapy to microsurgical resection to reduce the high-risk features of bAVMs such as large size and high flow. However, the effect of preoperative embolization on surgical performance and patient outcome has shown mixed results. Heterogeneity in treatment goals, selection criteria, and unpredictable changes in bAVM hemodynamics after partial embolization may account for these uncertain findings. In this study we use an objective quantitative technique to assess the impact of preoperative embolization on intraoperative blood loss (IBL). METHODS: Patients with bAVM treated with microsurgical resection only or in combination with preoperative embolization from 2012 to 2022 were retrospectively reviewed. Patients were included if quantitative magnetic resonance angiography was performed prior to any treatment. Correlation of baseline bAVM flow, volume, and IBL was evaluated between the two groups. Additionally, bAVM flow prior to and after embolization was compared. RESULTS: Forty-three patients were included, 31 of whom required preoperative embolization (20 had more than one session). Mean bAVM initial flow (362.3 mL/min vs 89.6 mL/min, p=0.001) and volume (9.6 mL vs 2.8 mL, p=0.001) were significantly higher in the preoperative embolization group; flow decreased significantly after embolization (408.0 mL/min vs 139.5 mL/min, p<0.001). IBL was comparable between the two groups (258.6 mL vs 141.3 mL, p=0.17). Linear regression continued to show a significant difference in initial bAVM flow (p=0.03) but no significant difference in IBL (p=0.53). CONCLUSION: Patients with larger bAVMs who underwent preoperative embolization had comparable IBL to those with smaller bAVMs undergoing only surgical treatment. Preoperative embolization of high-flow bAVMs facilitates surgical resection, reducing the risk of IBL.

Microsurgical Clipping of a Ruptured Basilar-P1 Junction Aneurysm.

In current neurosurgical practice, treatment paradigms for posterior circulation aneurysms have shifted away from microsurgical clip ligation toward endovascular therapy. This is largely due to the results of the International Subarachnoid Aneurysm Trial and International Study of Unruptured Intracranial Aneurysms, which, in part, showed that outcomes in patients with ruptured aneurysms were better with coiling and that a location in the posterior circulation was an independent risk factor for poor outcome, respectively.1,2 Nevertheless, there exist certain anatomic features that highlight the importance of a microsurgical approach. These include small size, wide-neck configuration, and the incorporation of perforators, among other factors. In Video 1, we report a case of a 53-year-old male with a ruptured 2 mm × 2 mm right basilar-P1 junction aneurysm. Endovascular options were deemed less favorable due to the small size of the aneurysm and the hemorrhagic complications associated with dual-antiplatelet therapy in the setting of an acute subarachnoid hemorrhage. A standard right-sided orbitozygomatic approach was performed.3 This video highlights the importance of performing microsurgical clipping for posterior circulation aneurysms in an era with increasing reliance on endovascular treatment.

Impact of cerebral aneurysm size on distal intracranial hemodynamics and changes following flow diversion.

BACKGROUND: The impact of cerebral aneurysm size on distal intracranial hemodynamics such as arterial pressure and Pulsatility Index is not completely understood, either before or after flow diversion. OBJECTIVE: The aim of the study is to assess the impact of aneurysm size on distal Pulsatility Index and pressure before and after flow diversion. METHODS: From December 2015, prospective measurement of middle cerebral artery pressure and Pulsatility Index was performed in consecutive patients with unruptured cerebral aneurysms in the cavernous to communicating segments of the internal carotid artery, which were treated with single flow diversion. Pressure and Pulsatility Index were recorded at the M1-segment ipsilateral to the cerebral aneurysm. Ratio of middle cerebral artery to radial arterial pressure (pressure ratio) was calculated to control for variations in systemic blood pressure. Correlations between aneurysm size and pressure ratio and Pulsatility Index were assessed before and after treatment. RESULTS: A total of 28 aneurysms were treated. The mean aneurysm size was 7.2 mm. Aneurysm size correlated linearly with systolic pressure ratio (1% pressure ratio increase per mm aneurysm size increase, P = 0.002, r2 = 0.33), mean pressure ratio (0.6% per mm, P = 0.03, r2 = 0.17) and Pulsatility Index (5% Pulsatility Index increase per mm, P = 0.003, r2 = 0.43). After flow diversion, aneurysm size preserved a linear correlation with the systolic pressure ratio (1% per mm, P = 0.004, r2 = 0.28), but not with the mean pressure ratio (0.4% per mm, P = 0.15, r2 < 0.1) or Pulsatility Index (0.3% per mm, P = 0.78, r2 < 0.1). CONCLUSION: Aneurysm size affects distal hemodynamics: patients with larger aneurysms have increased systolic and mean pressure ratio, and increased Pulsatility Index. After flow diversion, mean pressure ratio and Pulsatility Index no longer associate with the aneurysm size, suggesting an effect of the flow diversion also on distal intracranial hemodynamics.

Chronic invasive fungal sinusitis with orbital and olfactory cleft involvement secondary to indolent mucormycosis.

PURPOSE: Chronic invasive fungal sinusitis secondary to indolent mucormycosis is a rare clinical entity, and the ideal management is controversial. A case of indolent mucormycosis successfully managed with conservative debridement and retrobulbar amphotericin B is herein reported. OBSERVATIONS: A 42-year-old man with diabetes mellitus and kidney transplant presented with chronic invasive fungal sinusitis with left orbital involvement from indolent mucormycosis. The patient was treated with aggressive systemic antifungal therapy, left retrobulbar injection of liposomal amphotericin B, reduction in immunosuppression, and conservative surgical debridement. Although the left olfactory cleft was involved, the cribriform plate was not resected due to risk of seeding the intracranial space. Given mild orbital involvement, no orbital debridement was performed and the patient had resolution of his orbital findings with systemic and retrobulbar amphotericin B. The patient had clinical and radiographic stability at 6-month follow-up. CONCLUSIONS: Conservative resection with subsequent long-term antifungal treatment can be a successful regimen in indolent mucormycosis. Retrobulbar amphotericin B may be a prudent orbit-sparing adjuvant therapy in indolent mucormycosis.

Delayed intracerebral hemorrhage from a traumatic carotid-cavernous fistula associated with an enucleated orbit.

Spontaneous intracerebral hemorrhage (ICH) from a traumatic carotid-cavernous fistula (CCF) is a rare occurrence with few cases reported in the literature. Patients classically present shortly after the inciting trauma with symptoms of ocular venous hypertension. We report a case of an ICH due to delayed rupture of a venous aneurysm from a CCF in a patient with decades-old history of enucleation of the left globe secondary to trauma with no sentinel symptoms. Our patient represents a unique presentation of a rare pathology. This case highlights the need for ongoing surveillance in patients with a history of severe craniofacial trauma, as ICH from ruptured CCF(s) demands emergent treatment due to the potential for rapid neurological deterioration.

Intracranial Leiomyoma Associated with Epstein-Barr Virus: A Cerebellopontine Angle Mass Presenting with Trigeminal Neuralgia.

BACKGROUND: Primary intracranial leiomyoma is a rare smooth muscle tumor often associated with Epstein-Barr virus (EBV), with <30 cases reported worldwide. These tumors commonly occur in patients with immunocompromised status, especially those with human immunodeficiency virus. In the present report, we have described the case of an EBV-associated leiomyoma at the cerebellopontine angle. The patient had presented with trigeminal neuralgia, which, to the best of our knowledge, is the first reported anatomical location and presentation for this tumor type. CASE DESCRIPTION: A 41-year-old male patient had presented with right-sided facial pain in the V1 and V2 dermatomes and previous workup and imaging studies. The patient had undergone treatment of a presumed right-side cerebellopontine angle meningioma as determined by the magnetic resonance imaging characteristics (no biopsy). The patient subsequently underwent right-sided retrosigmoid craniotomy and gross total resection of the tumor. The postoperative period was uneventful with resolution of the trigeminal neuralgia. Histopathologic examination revealed spindle cell neoplasm with histopathologic and immunohistochemical features consistent with leiomyoma. The tumor cells were positive for smooth muscle actin and desmin and were negative for S100, SOX-10, epithelial membrane antigen, glial fibrillary acidic protein, progesterone receptor, CD31, CD34, and E-cadherin. CONCLUSIONS: Primary intracranial leiomyomas are rare tumors associated with EBV infection that occur in immunocompromised patients. These lesions should be considered in the differential diagnosis for patients with known immunocompromised status (e.g., human immunodeficiency virus), and tissue biopsy should be considered.

Intracranial venous sinus stenosis: hemodynamic assessment with two-dimensional parametric parenchymal blood flow software on digital subtraction angiography.

OBJECTIVE: Intracranial venous sinus stenosis (IVSS) is the most common finding associated with idiopathic intracranial hypertension. A pressure gradient >8-10 mm Hg across the stenosis is considered hemodynamically significant, and typically responds to endovascular stent treatment. Here we assess the venous hemodynamics with two-dimensional (2D) parametric parenchymal blood flow software (Siemens-Healthineers, Forchheim, Germany) and its ability to predict significant IVSS. METHODS: Patients with IVSS treated at our institution between 2013 and 2018 were retrospectively reviewed. Measurements of contrast transit time on DSA were calculated with 2D parametric parenchymal blood flow software. Values were obtained proximally and distally to the stenotic region. Venous Stenosis Index (VSI) was defined as the ratio of the area under the curve (AUC) in the pre-stenotic vessel to the AUC in the post-stenotic vessel. VSI was compared between the stenotic and control groups at baseline, and before and after stent deployment in the stenotic group. The accuracy of VSI was assessed using the non-parametric receiver operating characteristic (ROC) curve. RESULTS: 11 patients with IVSS treated with venous stent deployment were included. Patients in the control group were similar in age, gender, and absence of major comorbidities. VSI in the IVSS group was significantly higher at baseline compared with the control group (1.42 vs 0.97, p=0.01). Area under the ROC was 0.82. After stent deployment, VSI decreased significantly compared with baseline (1.04 vs 1.42, p<0.01). CONCLUSION: 2D parametric parenchymal blood flow software is a useful tool which can accurately evaluate significant hemodynamic venous stenosis without intracranial catheterization, added radiation exposure, additional contrast injection, and periprocedural risks.

Predictors of Poor Outcome Despite Successful Mechanical Thrombectomy of Anterior Circulation Large Vessel Occlusions Within 6 h of Symptom Onset.

Background and Purpose: Successful reperfusion is a significant predictor of a good clinical outcome after mechanical thrombectomy (MT). However, some patients have a poor clinical outcome even with successful reperfusion. We aimed to study factors that predict a poor clinical outcome (90-day modified Rankin Scale ≥ 3) in patients with anterior circulation large vessel occlusion (LVO) treated by successful MT within 6 h of symptom onset. Methods: We performed a retrospective review of a prospectively maintained MT database of all patients who underwent MT within 6 h of symptom onset for an anterior circulation LVO at our institution from May 2016 to June 2018. Uni- and multivariable analyses were performed to identify predictors of poor outcome. Results: A total of 56 patients met the criteria for inclusion in this study. A poor outcome occurred in 31 (55.4%) patients. On univariate analysis, compared to patients with good clinical outcome, patients with poor outcome had higher mean baseline NIHSS scores (23.3 vs. 13.8, P < 0.001), were more likely to have internal carotid artery (ICA) occlusions (38.7 vs. 8%, P = 0.008), and had a higher incidence of distal clot migration (DCM) (48.4 vs. 8%, P = 0.028). Age, gender, other baseline clinical characteristics, MT technique, and incidence of hemorrhagic transformation did not differ between the two cohorts. On multivariable regression analysis, baseline NIHSS score [OR; 1.3, 95%CI [1.11-1.52], P = 0.001], site of occlusion (ICA) [OR; 8.9, 95%CI [1.3-60.9], P = 0.026], and DCM [OR; 5.77, 95%CI [1.09-30.69], P = 0.04] were independent predictors of poor outcome at 90-days. Conclusion: Baseline NIHSS score, ICA occlusion, and DCM are independent predictors of a poor outcome after MT for anterior circulation LVO performed within 6 h of symptoms onset.

2D parametric contrast time-density analysis for the prediction of complete aneurysm occlusion at six months' post-flow diversion stent.

OBJECTIVE: Indications for the treatment of cerebral aneurysms with flow diversion stents are expanding. The current aneurysm occlusion rate at six months ranges between 60 and 80%. Predictability of complete vs. partial aneurysm occlusion is poorly defined. Here, we evaluate the angiographic contrast time-density as a predictor of aneurysm occlusion rate at six months' post-flow diversion stents. METHODS: Patients with unruptured cerebral aneurysms proximal to the internal carotid artery terminus treated with single flow diversion stents were included. 2D parametric parenchymal blood flow software (Siemens-Healthineers, Forchheim, Germany) was used to calculate contrast time-density within the aneurysm and in the proximal adjacent internal carotid artery. The area under the curve ratio between the two regions of interests was assessed at baseline and after flow diversion stents deployment. The area under the curve ratio between completely vs. partially occluded aneurysms at six months' follow-up was compared. RESULTS: Thirty patients with 31 aneurysms were included. Mean aneurysm diameter was 8 mm (range 2-28 mm). Complete occlusion was obtained in 19 aneurysms. Younger patients (P = 0.006) and smaller aneurysms (P = 0.046) presented higher chance of complete obliteration. Incomplete occlusion of the aneurysm was more likely if the area under the curve contrast time-density ratio showed absolute (P = 0.001) and relative percentage (P = 0.001) decrease after flow diversion stents deployment. Area under ROC curve was 0.85. CONCLUSION: Negative change in the area under the curve ratio indicates less contrast stagnation in the aneurysm and lower chance of occlusion. These data provide a real-time analysis after aneurysm treatment. If validated in larger datasets, this can prompt input to the surgeon to place a second flow diversion stents.

Role of Resistivity Index Analysis in the Prediction of Hemodynamically Significant Venous Sinus Stenosis in Patient With Idiopathic Intracranial Hypertension.

BACKGROUND: The resistivity index (RI) in cerebral venous sinus stenosis (VSS) has not been studied in patients with idiopathic intracranial hypertension (IIH). OBJECTIVE: To evaluate the role of RI measured by quantitative magnetic resonance venogram (QMRV) as a noninvasive tool in the diagnosis of venous hypertension associated with VSS in IIH. METHODS: Retrospective evaluation of 13 consecutive IIH patients who underwent venous sinus stenting at our institution between 2013 and 2018.Patients' demographics, clinical presentation, cerebral mean venous sinus pressure (MVP), and RI both pre- and poststenting were recorded. The baseline RI was also compared to a control group. RESULTS: Among 13 patients of IIH, 11 had unilateral VSS in dominant sinus, whereas 2 had bilateral VSS. RI was significantly higher in IIH patients compared to the control group in the superior sagittal (SSS) and transverse sinuses (TS) (0.21 vs 0.11, P = .01 and 0.22 vs 0.13, P = .03, respectively). The MVP (in mm Hg) decreased significantly after venous sinus stenting in the SSS (41.9 to 22.5, P < .001) and TS (39.4 to 19.5, P < .001), which was also associated with a significant reduction of the RI (0.22 vs 0.17, P < .01 in SSS and 0.23 vs 0.17, P = .03 in TS) poststenting. CONCLUSION: RI calculated using QMRV can serve as a noninvasive tool to aid in the diagnosis of hemodynamically significant VSS. The study had a small sample size, and larger multicenter studies would be required to validate the results further.

The cut flow index revisited: utility of intraoperative blood flow measurements in extracranial-intracranial bypass surgery for ischemic cerebrovascular disease.

OBJECTIVE: In extracranial-intracranial (EC-IC) bypass surgery, the cut flow index (CFI) is the ratio of bypass flow (ml/min) to donor vessel cut flow (ml/min), and a CFI ≥ 0.5 has been shown to correlate with bypass patency. The authors sought to validate this observation in a large cohort of EC-IC bypasses for ischemic cerebrovascular disease with long-term angiographic follow-up. METHODS: All intracranial bypass procedures performed at a single institution between 2003 and 2018 were reviewed. Demographic, clinical, angiographic, and operative data were recorded and analyzed according to bypass patency with univariate and multivariate statistical analyses. RESULTS: A total of 278 consecutive intracranial bypasses were performed during the study period, of which 157 (56.5%) were EC-IC bypasses for ischemic cerebrovascular disease. Intraoperative blood flow measurements were available in 146 patients, and angiographic follow-up was available at a mean of 2.1 ± 2.6 years after bypass. The mean CFI was significantly higher in patients with patent bypasses (0.92 vs 0.64, p = 0.003). The bypass patency rate was 83.1% in cases with a CFI ≥ 0.5 compared with 46.4% in cases with a CFI < 0.5 (p < 0.0001). Adjusting for age, sex, diagnosis, and single versus double anastomosis, the CFI remained a significant predictor of bypass patency (p = 0.001; OR 5.8, 95% CI 2.0-19.0). A low CFI was also associated with early versus late bypass nonpatency (p = 0.008). CONCLUSIONS: A favorable CFI portends long-term EC-IC bypass patency, while a poor CFI predicts eventual bypass nonpatency and can alert surgeons to potential problems with the donor vessel, anastomosis, or recipient bed during surgery.

High-Definition Zoom Mode: A High Resolution X-ray Microscope for Neurointerventional Treatment Procedures.

BACKGROUND AND PURPOSE: Visualization of structural details of treatment devices during neurointerventional procedures can be challenging. A new true two-resolution imaging X-ray detector system features a 194 µm pixel conventional flat-panel detector (FPD) mode and a 76 µm pixel high-resolution high-definition (Hi-Def) zoom mode in one detector panel. The Hi-Def zoom mode was developed for use in interventional procedures requiring superior image quality over a small field of view (FOV). We report successful use of this imaging system during intracranial aneurysm treatment in 1 patient with a Pipeline-embolization device and 1 patient with a low-profile visualized intramural support (LVIS Blue) device plus adjunctive coiling. METHODS: A guide catheter was advanced from the femoral artery insertion site to the proximity of each lesion using standard FPD mode. Under magnified small FOV Hi-Def imaging mode, an intermediate catheter and microcatheters were guided to the treatment site, and the PED and LVIS Blue plus coils were deployed. Radiation doses were tracked intraprocedurally. RESULTS: Critical details, including structural changes in the PED and LVIS Blue and position and movement of the microcatheter tip within the coil mass, were more readily apparent in Hi-Def mode. Skin-dose mapping indicated that Hi-Def mode limited radiation exposure to the smaller FOV of the treatment area. CONCLUSIONS: Visualization of device structures was much improved in the high-resolution Hi-Def mode, leading to easier, more controlled deployment of stents and coils than conventional FPD mode.

Management of Acute Ischemic Thrombosis.

Acute ischemic thrombosis in patients who have undergone neurosurgical procedures is a leading cause of mortality and long-term disability. Endovascular therapy has become an important treatment modality for acute ischemic thrombosis in these patients. Noninvasive imaging has dramatically changed the understanding of cerebral blood flow and the concepts of cerebrovascular reserve and salvageable penumbra. Increasingly, reliance on perfusion imaging to discern tissue viability and potential outcomes has become standard of care. With the advent of recent acute ischemic stroke trials, therapy for occlusive cerebrovascular disease is evolving, and understanding when to intervene is becoming paramount.

Transtentorial herniation from tumefactive multiple sclerosis mimicking primary brain tumor.

BACKGROUND: Multiple sclerosis (MS) is a chronic central nervous system inflammatory demyelinating disease characterized by multiple lesions disseminated in time and space. The lesions often have characteristic imaging findings on magnetic resonance (MR) imaging and cerebrospinal fluid findings that lead to their diagnosis. At times, these lesions may resemble tumors due to their large size (>2 cm), significant vasogenic edema, and ring-enhancing MR imaging findings. Such lesions are described as tumefactive demyelinating lesions or tumefactive MS, and they are generally seen in aggressive forms of MS associated with rapid progression. CASE DESCRIPTION: We report an uncommon but clinically significant case of transtentorial brain herniation secondary to malignant cerebral edema from tumefactive MS in a 50-year-old woman. After the initial diagnosis of MS, the patient continued to have progression of her white matter lesions suggesting evolution of her MS despite treatment with intravenous (IV) steroids, IV immunoglobulin, and plasmapheresis. She was admitted to the hospital with a new, large, ring-enhancing lesion that displayed significant mass effect from vasogenic edema and progressed, necessitating a decompressive hemicraniectomy. CONCLUSION: Tumefactive MS presents a unique pathology that can often mimic primary brain tumors. Although these lesions affect white matter and infrequently cause a significant amount of mass effect, they can act like a tumor, causing edema that generates sufficient intracranial pressure to cause transtentorial herniation.

Computer-Assisted Three-Dimensional Morphology Evaluation of Intracranial Aneurysms.

OBJECTIVE: Precise morphologic evaluation is important for intracranial aneurysm (IA) management. At present, clinicians manually measure the IA size and neck diameter on 2-dimensional (2D) digital subtraction angiographic (DSA) images and categorize the IA shape as regular or irregular on 3-dimensional (3D)-DSA images, which could result in inconsistency and bias. We investigated whether a computer-assisted 3D analytical approach could improve IA morphology assessment. METHODS: Five neurointerventionists evaluated the size, neck diameter, and shape of 39 IAs using current and computer-assisted 3D approaches. In the computer-assisted 3D approach, the size, neck diameter, and undulation index (UI, a shape irregularity metric) were extracted using semiautomated reconstruction of aneurysm geometry using 3D-DSA, followed by IA neck identification and computerized geometry assessment. RESULTS: The size and neck diameter measured using the manual 2D approach were smaller than computer-assisted 3D measurements by 2.01 mm (P < 0.001) and 1.85 mm (P < 0.001), respectively. Applying the definitions of small IAs (<7 mm) and narrow-necked IAs (<4 mm) from the reported data, interrater variation in manual 2D measurements resulted in inconsistent classification of the size of 14 IAs and the necks of 19 IAs. Visual inspection resulted in an inconsistent shape classification for 23 IAs among the raters. Greater consistency was achieved using the computer-assisted 3D approach for size (intraclass correlation coefficient [ICC], 1.00), neck measurements (ICC, 0.96), and shape quantification (UI; ICC, 0.94). CONCLUSIONS: Computer-assisted 3D morphology analysis can improve accuracy and consistency in measurements compared with manual 2D measurements. It can also more reliably quantify shape irregularity using the UI. Future application of computer-assisted analysis tools could help clinicians standardize morphology evaluations, leading to more consistent IA evaluations.