Refinement of nBCA embolization technique in treatment of metastatic spinal tumors: Case series and technical report.

BACKGROUND AND OBJECTIVES: Preoperative embolization of metastatic spinal tumors (MSTs) has proven advantageous in limiting intraoperative blood loss (IBL) during resection. N-butyl cyanoacrylate (nBCA) is a liquid embolic agent known for its rapid hemostatic effects. However, nBCA is associated with a higher risk of distal nontarget embolization. This study highlights the refinement of the embolization technique and assesses its efficacy in performing an initial distal segmental artery plug with concentrated nBCA followed by proximal diluted nBCA for MSTs. METHODS: A retrospective review of patients with MST (2018-2023) was performed. Patients who underwent preoperative nBCA endovascular embolization prior to tumor resection and spinal instrumentation were included. Baseline standard spinal angiography was performed. RESULTS: Sixteen patients (13 men, 3 women; 56.0 ± 12.4 years) met inclusion criteria. And 43.75% (7 of 16) had thoracic levels, 37.5% (6 of 16) lumbar, and 18.75% (3 of 16) sacral. The most common primary tumor was renal cell carcinoma (43.75%, 7 of 16). A total of 43 pedicles were embolized (median 3), resulting in complete/near complete obliteration of the tumor blush. Most pedicles (83.7%, 36 of 43) received a single dilute concentration of nBCA; however, 16.3% (7 of 43) received two separate concentrations of nBCA, a denser concentration distally into the segmental artery and a diluted concentration proximally into the tumor bed. Mean IBL was 1150 ± 1201 mL in 3 distal plug patients distal plug patients versus 1625 ± 681 mL in 12 other patients. There were no complications related to embolization. CONCLUSION: Performing a distal, concentrated nBCA plug during preoperative nBCA embolization of MSTs may increase tumor penetration and reduce IBL.

The correlation of cerebral arteriovenous malformation flow measured by quantitative MR angiography on MR-detected arteriovenous malformation microhemorrhage.

OBJECTIVE: The objective of this study was to assess the relationship of arteriovenous malformation (AVM) blood flow measured by quantitative MR angiography (QMRA) in nonruptured AVMs with MR-detected microhemorrhage. METHODS: All patients with unruptured AVMs who received baseline QMRA and gradient echo or susceptibility-weighted MRI were retrospectively reviewed (2004-2022). Imaging data, clinical history, and AVM angioarchitectural and flow features were collected and assessed. AVM flow was calculated from the difference of flow within primary arterial feeders from their contralateral counterparts. A review of the MR images determined the presence of microhemorrhages. Analysis of descriptive statistics, chi-square test, and binomial logistic regression were performed. RESULTS: Of 634 patients with cerebral AVMs at a single center, 89 patients met the inclusion criteria (54 with microhemorrhage and 35 without microhemorrhage). The calculated AVM flow was significantly higher in the group with a microhemorrhage (447.9 ± 193.1 ml/min vs 287.6 ± 235.7 ml/min, p = 0.009). In addition, the presence of venous anomaly, arterial ectasia, and diffuse nidus was significantly associated with microhemorrhage (p = 0.017, p = 0.041, and p = 0.041, respectively). Binary logistic regression found that higher flow predicted the presence of microhemorrhage (OR 1.002, 95% CI 1.000-1.004; p = 0.031). The highest AVM flow quartile significantly predicted the presence of venous anomaly (OR 3.840, 95% CI 1.037-14.213; p = 0.044), diffuse nidus (OR 6.800, 95% CI 1.766-25.181; p = 0.005), and arterial ectasia (OR 13.846, 95% CI 1.905-122.584; p = 0.018). CONCLUSIONS: This study represents the first to examine the association between flow measurements on QMRA with microhemorrhage in unruptured AVMs. Higher AVM flow, venous anomaly, arterial ectasia, and diffuse AVM nidus were related to a higher likelihood of AVM microhemorrhage. Higher AVM flow was present in AVMs with venous anomalies, a diffuse nidus, and arterial ectasia, indicating a possible interaction between these angioarchitectural findings, AVM flow, and microhemorrhage. These findings suggest a relationship between higher AVM flow and the risk of microhemorrhage.

Predictors of angiographic resolution in patients with presumed reversible cerebral vasoconstriction syndrome.

INTRODUCTION: Reversible cerebral vasoconstriction syndrome is a complex neurovascular syndrome that presents with varying neurological deficits as well as segmental vasoconstriction of the small and medium cerebral arteries. There is limited literature on pathologies that mimic reversible cerebral vasoconstriction syndrome, so this study aims to understand what factors may impact the angiographic confirmation of reversible cerebral vasoconstriction syndrome on follow-up and play a role in establishing the diagnosis. METHODS: The Clinical Research Data Warehouse at this institution was employed to search the medical records for patients with diagnosis and treatment of reversible cerebral vasoconstriction syndrome between January 2010 and May 2021. After screening, 32 patients met the inclusion criteria for a presumed diagnosis of reversible cerebral vasoconstriction syndrome with both angiography on presentation and at three-month follow-up after treatment. Patients were divided into two categories: those with complete angiographic resolution, versus partial or no improvement on follow-up. Clinical and radiographic data were analyzed. RESULTS: Patients who had partial or no resolution were more likely to have a history of hypertension (p = 0.001), higher systolic blood pressure on admission (p = 0.047), and present with a recurrent thunderclap headache (p = 0.038). Binary logistic regression selected for hypertension (odds ratio [OR] 18.35 [95% CI, 1.37-245.1]) as predictive of not having reversible cerebral vasoconstriction syndrome, as can be seen by partial or no resolution on follow-up angiography (p = 0.028). CONCLUSION: Complete resolution on follow-up angiography is a distinguishing factor of reversible cerebral vasoconstriction syndrome. Our analysis revealed that a history of hypertension is the most significant predictor of confirming that a patient may not have reversible cerebral vasoconstriction syndrome. This is due, in part, to increased atherosclerotic or hypertensive cerebral arterial changes, which can mimic reversible cerebral vasoconstriction syndrome and present as partial or no resolution on angiography.