Contrast-Enhanced Ultrasonography and Color Doppler: Guided Intraoperative Embolization of Intracranial Highly Vascularized Tumors

Direct puncture embolization of a medulla oblongata hemangioblastoma

Hemangioblastoma is a rare tumor of vascular origin, most commonly located in the posterior fossa, which presents with severe symptoms and usually very hard to resect without remarkable operative blood loss.1-2 Pre-operative embolization may decrease the amount of intra-operative bleeding, but the endovascular treatment of such tumor may be very challenging due to the high risk of infarction of the surrounding tissues. Direct puncture embolization has been developed to overcome many of the limitations of endovascular techniques for many hypervascular lesions, also hemangioblastomas.3-5 We present in this Technical Video (video 1) a direct puncture embolization with balloon-protection of a hemangioblastoma of the medulla oblongata using Onyx 18 (Medtronic, inc.) as sole liquid embolic agent.

Sporadic and von Hippel-Lindau Related Hemangioblastomas of Brain and Spinal Cord: Multimodal Imaging for Intraoperative Strategy

Hemangioblastomas (HBs) are rare, benign tumors often related to von Hippel-Lindau disease. They represent the most frequent primary cerebellar tumors in adults. Neurosurgical procedures aim to obtain a gross-total resection of tumor nodules, avoiding intra-postoperative hemorrhage. The introduction of new intraoperative imaging techniques has considerably changed surgical strategies in neuro-oncology. We present an overview of clinical and radiological data of a mono-institutional retrospective cohort, focusing on the role of intraoperative multimodal imaging in surgical strategy. From 2015 to 2021, we identified 64 (81%) cranial (42 cerebellar, 8 supratentorial, and 14 of the brainstem) HBs and 15 (19%) spinal (4 cervical and 11 dorsal) HBs in 79 patients. Intraoperatively, indocyanine green videoangiography with FLOW800 was used in 62 cases (52 cranial and 10 spinal), intraoperative ultrasound and contrast-enhanced ultrasounds in 22 cases (18 cranial and 4 spinal HBs), and fluorescein in 10 cases (in 6 cranial and 2 spinal cases used as SF-VA). Gross total resection was achieved in 100% of the cases (53 mural nodule removal and 26 complete resections of the solid tumor). No side effects were reported following the combination of these tools. Multimodal intraoperative techniques provide valuable and reliable information to identify the tumor and its vasculature, guiding a more precise and safer resection and reducing the risk of recurrence.

High Grade Glioma Treatment in Elderly People: Is It Different Than in Younger Patients? Analysis of Surgical Management Guided by an Intraoperative Multimodal Approach and Its Impact on Clinical Outcome

OBJECTIVE

Age is considered a negative prognostic factor for High Grade Gliomas (HGGs) and many neurosurgeons remain skeptical about the benefits of aggressive treatment. New surgical and technological improvements may allow extended safe resection, with lower level of post-operative complications. This opportunity opens the unsolved question about the most appropriate HGG treatment in elderly patients. The aim of this study is to analyze if HGG maximal safe resection guided by an intraoperative multimodal imaging protocol coupled with neuromonitoring is associated with differences in outcome in elderly patients versus younger ones.

METHODS

We reviewed 100 patients, 53 (53%) males and 47 (47%) females, with median (IQR) age of 64 (57; 72) years. Eight patients were diagnosed with Anaplastic Astrocytoma (AA), 92 with Glioblastoma (GBM). Surgery was aimed to achieve safe maximal resection. An intraoperative multimodal imaging protocol, including neuronavigation, neurophysiological monitoring, 5-ALA fluorescence, 11C MET-PET, navigated i-US system and i-CT, was used, and its impact on EOTR and clinical outcome in elderly patients was analyzed. We divided patients in two groups according to their age: <65 and >65 years, and surgical and clinical results (EOTR, post-operative KPS, OS and PFS) were compared. Yet, to better understand age-related differences, the same patient cohort was also divided into <70 and >70 years and all the above data reanalyzed.

RESULTS

In the first cohort division, we did not found KPS difference over time and survival analysis did not show significant difference between the two groups (p = 0.36 for OS and p = 0.49 for PFS). Same results were obtained increasing the age cut-off for age up to 70 years (p = 0.52 for OS and p = 0.92 for PFS).

CONCLUSIONS

Our data demonstrate that there is not statistically significant difference in post-operative EOTR, KPS, OS, and PFS between younger and elderly patients treated with extensive tumor resection aided by a intraoperative multimodal protocol.

Combined Use of Color Doppler Ultrasound and Contrast-Enhanced Ultrasound in the Intraoperative Armamentarium for Arteriovenous Malformation Surgery

BACKGROUND

Safety and efficacy in surgical treatment of cerebral arteriovenous malformations (AVMs) are dictated by thorough understanding of angioarchitectural features, intraoperative identification of feeding vessels, and appreciation of surrounding eloquent areas. Our aim was to describe the preliminary results of combined application of color Doppler ultrasound (CDUS) and contrast-enhanced ultrasound (CEUS) in a consecutive surgical series of AVM. We pointed out the tool's efficacy in distinguishing feeding from bystander vessels and in identifying pattern of venous drainage. We examined its role as an adjunct for semiquantitative evaluation of the nidus inflow.

METHODS

We used combined CDUS and CEUS in patients surgically treated for cerebral AVMs. We adopted these techniques following a designed protocol to guide safer AVM resection as an adjunct to indocyanine green videoangiography. Intraoperative assessment by ultrasound was performed before, during, and following nidus resection.

RESULTS

Four surgically treated cerebral AVMs availed of the ultrasound protocol. Postoperative conventional angiography showed complete resection of the AVMs. CDUS and CEUS proved to be valuable adjunctive tools to indocyanine green videoangiography and micro-Doppler in properly navigating and discerning vascular structures, especially vessel feeders from bystanders. The protocol allows us to identify flow direction, estimate blood velocity within the nidus, and appreciate flow modifications following temporary clipping. Ultimately, it allows us to evaluate the degree of nidus deafferentation, residual flow, restoration of venous drainage and absence of arteriovenous shunts.

CONCLUSIONS

The CDUS and CEUS protocol is safe and repeatable and works as real-time imaging, further supporting complete surgical resection of AVMs.

Transcranial Sonography versus CT for Postoperative Monitoring After Decompressive Craniectomy

BACKGROUND AND PURPOSE

Computed tomography (CT) is the actual gold standard diagnostic tool for monitoring patients after decompressive craniectomy. It is validated and provides a wide number of information. However, it takes time, expensive, and requires patient transportation. Transcranial sonography (TCS) could represent an alternative diagnostic tool in these patients. The aim of this study is to compare TCS versus CT scan after decompressive craniectomy in terms of diagnosing complications and costs evaluation.

METHODS

We prospectively enrolled 10 craniectomized patients who were monitored with sonography and CT. Ventricular measurements and possible complications were evaluated by two independent observers. The two methods were compared using Fisher's exact test and Spearman's Rho coefficient. A costs analysis was also conducted.

RESULTS

A good correlation coefficient (ρ) between CT and TCS was found for frontal horn dimensions (ρ .9929), median cella (ρ .9516), and third ventricle (ρ .8989). All results were statistically significant (P < .0001) and Bland-Altman plots showed no systemic biases. Fisher's exact test showed no statistically significant differences between TCS and CT for all the studied predefined complications. Cost analysis showed a 68% cost reduction in favor of TCS.

CONCLUSIONS

TCS could be a reliable alternative diagnostic tool for major complications in patients undergoing decompressive craniectomy. It could limit the number of CT scans per patient overcoming several limitations, such as costs, radiation exposure, and need to move the patient.

"Dark corridors" in 5-ALA resection of high-grade gliomas: combining fluorescence-guided surgery and contrast-enhanced ultrasonography to better explore the surgical field

BACKGROUND

Increasing the extent of resection (EOR) is considered a main goal in high grade glioma (HGG) surgery. Significant advancements have been recently made to assist surgery: namely the use of 5-aminolevulinic acid (5ALA) and the application of contrast-enhanced ultrasound (CEUS) embody two of the most recently introduced tools in the neuro-oncology field. A combined approach including the two techniques has been suggested in literature. Our primary aim is to identify in which conditions CEUS final survey has a real impact in a 5-ALA guided context and assess which preoperative tumor characteristics, with specific attention to working corridors can predict strains of the fluorescence guided procedure and hence recommend the use of the combined technique.

METHODS

Forty-nine HGG glioma surgeries were performed at our institution with the abovementioned protocol between January 2016 and June 2016. Based on preoperative MRI, we stratified glioma characteristics according to three determinants: localization (deep versus superficial), size (<3.5 versus >3.5 cm) and shape (regular versus irregular).

RESULTS

CEUS modified 5-ALA guided resection in 11 cases (22.45%): this appeared to be associated with statistically significance to deep tumor localization (P=0.04) and irregular/multi-lobulated margins (P=0.003). On the other hand, tumor size alone did not appear as a statistically significant determinant.

CONCLUSIONS

When dark corridors are presents or when overlying brain parenchyma hinders illumination, drawbacks to the 5-ALA assistance can be expected, hence CEUS final survey has a crucial role of 'refinement'. In those selected cases, an integrated 5ALA+CEUS protocol was shown as advisable in EOR improvement.

The role of contrast-enhanced ultrasound in neurosurgical disease

Contrast-enhanced ultrasound (CEUS) is a relatively new imaging modality in the realm of neurosurgical disease. CEUS permits the examination of blood flow through arteries, veins, and capillaries via intravascular contrast agents and allows vascular architectural mapping with extreme sensitivity and specificity. While it has established utility in other organ systems such as the liver and kidneys, CEUS has not been studied extensively in the brain. This report presents a review of the literature on the neurosurgical applications of CEUS and provides an outline of the imaging modality’s role in the diagnosis, evaluation, and treatment of neurosurgical disease.