Intraoperative color-flow Doppler imaging of AVM's and aneurysms

Intraoperative visualization of cerebral aneurysms using navigated 3D-ultrasound power-Doppler angiography

BACKGROUND

The questions of whether the spatial resolution of navigated 3D-ultrasound (3D-US) power-Doppler angiography imaging rendered by existing 3D-US systems is sufficient for the intraoperative visualization of cerebral aneurysms, and in what percentage of cases, are largely unanswered. A study on this topic is lacking in the literature.

METHODS

From 2015 to 2022, we performed 86 surgeries on 83 aneurysm patients. Navigated 3D-US was used at the discretion of the operating neurosurgeons when available (i.e., not being used during parallel tumor surgeries). Twenty-five aneurysms (15 ruptured) were operated on using 3D-US; 22 aneurysms were located at the middle cerebral artery (MCA). Patient 3D-US power-Doppler angiography images and surgical reports were retrospectively reviewed to assess the intraoperative ultrasound visibility of aneurysms.

RESULTS

In 20 patients (80%) the aneurysms were successfully visualized. In five patients (20%), the aneurysms visualization was insufficient or absent. Nineteen of 22 aneurysms (86.4%) were visualized in the MCA aneurysm subgroup. We observed no association between aneurysm visibility and aneurysm size or the presence of subarachnoid hemorrhage. In the subgroup of MCA aneurysms, no association between aneurysm visibility and the presence of subarachnoid hemorrhage was found; a trend toward poor sonographic visibility of smaller aneurysms was observed (p = 0.09).

CONCLUSIONS

Our initial data show that intraoperative 3D-US power-Doppler angiography, rendered by current navigated 3D-US systems, clearly depicts the majority of aneurysms in the MCA aneurysm subgroup. However, future prospective studies performed on a higher number of aneurysms localized at various anatomic sites are needed to confirm our initial findings and determine their potential clinical relevance.

Ultrasound localization of embolic material to guide resection of brain AVM: Report of two cases

Background

The Spetzler-Martin Grade (SMG) is widely used to evaluate the risk of resection of cerebral arteriovenous malformation (AVM), and direct surgery is strongly recommended for low SMG lesions. Micro-AVMs are defined as AVMs with a nidus <1 cm in diameter, and sometimes, the challenge is identifying the exact lesion site during AVM resection, although identification of the site is very important in the procedure. Here, we present two cases in which the sites of micro-AVM were marked using presurgical embolization and easily confirmed by intraoperative ultrasonography (IUS) and discuss the benefits of IUS in combination with presurgical embolization for low-grade micro-AVM.

Case Description

(Patient 1) A 30-year-old man was brought to our hospital and diagnosed with a micro-AVM, which was classified as SMG II AVM. He underwent evacuation of the intracerebral hematoma and subsequently underwent AVM resection. However, the lesion was not identified because it was not exposed in the cerebral cortex although we searched for the lesion. Therefore, endovascular embolization was performed before subsequent surgical resection. During AVM resection following embolization with Onyx, the IUS clearly demonstrated the Onyx-embolized lesion, and it was resected uneventfully. (Patient 2) A 46-year-old man with a ruptured SMG II AVM underwent AVM resection using a microsurgical technique with IUS after embolization for AVM preoperatively. IUS clearly showed abnormal vessels embolized with Onyx and indicated the correct location of the nidus, although the lesion was not observed directly from the brain surface. After identifying some embolized AVM constructions, we excised the entire AVM with ease and safety.

Conclusion

The combined use of presurgical embolization, which focuses on marking the lesions and IUS, may contribute to improving surgical outcomes of low SMG micro-AVMs, which are not exposed on the brain surface.

Application of hybrid operating rooms for treating spinal dural arteriovenous fistula

BACKGROUND

A hybrid operating room (hybrid-OR) is a surgical space that combines a conventional operating room with advanced medical imaging devices.

AIM

To explore and summarize the technical features and effectiveness of the application of a hybrid-OR in dealing with spinal dural arteriovenous fistulas (SDAVFs).

METHODS

Eleven patients with SDAVFs were treated with the use of a hybrid-OR at the Department of Neurosurgery of our hospital between January 2015 and December 2018. The dual-marker localization technique was used in the hybrid-OR to locate the SDAVFs and skin incision, and the interoperative digital subtraction angiography (DSA) technique was used before and after microsurgical ligation of the fistulae in the hybrid-OR to verify the accuracy of obliteration. The patients were followed for an average of 2 years after the operation, and the preoperative American Spinal Cord Injury Association (ASIA) score and postoperative ASIA score at 6 mo after the operation were compared.

RESULTS

The location and skin incision of the SDAVFs were accurately obtained by using the dual-marker localization technique in the hybrid-OR in all patients, and there were no cases that required expansion of the range of the bone window in order to expose the lesions. Intraoperative error obliteration occurred and was identified in two patients by using the intraoperative DSA technique; therefore, the findings provided by the intraoperative DSA system significantly changed the surgical procedure in these two patients. With the assistance of the hybrid-OR, the feeding artery was correctly ligated in all cases, and the intraoperative error obliteration rate decreased from 18.2% (2/11) to 0%. All 11 patients were followed for an average of 2 years. The ASIA score at 6 mo after the operation was significantly improved compared with the preoperative ASIA score, and there were no patients with late recurrence during the follow-up.

CONCLUSION

Compared with intra-arterial embolization for the treatment of SDAVFs, hybrid-ORs can solve the problem of a higher incidence of initial failure and late recurrence. Compared with direct occlusion of SDAVFs in microsurgery, hybrid-ORs can take advantage of the intraoperative DSA system for locating the shunt and verifying the obliteration of fistulae in order to reduce the error obliteration rate. At this point, our experience suggests that the safety and ease of use make hybrid-ORs combined with microsurgery and intraoperative DSA systems an attractive modality for dealing with SDAVFs.

Use of intraoperative Doppler ultrasound with neuronavigation to guide arteriovenous malformation resection: a pediatric case series

OBJECT

Over the last 20 years, several intraoperative adjuncts, including ultrasonography, neuronavigation, and angiography, have been said to aid the intraoperative localization and resection of cerebral arteriovenous malformations (AVMs). The authors assessed the value of intraoperative Doppler ultrasonography in conjunction with neuronavigation during surgery for cerebral AVMs in the pediatric population.

METHODS

The authors reviewed all cranial AVM resections performed by a single surgeon at their institution in the period from 2007 to 2013 and here describe their experience and results in a series of 20 consecutive AVM resections in 19 pediatric patients. Intraoperative Doppler ultrasonography had been used in conjunction with preoperative CT or neuronavigational MRI. Preoperative and postoperative clinical findings, patient age, and Spetzler-Martin AVM grade were identified in all patients.

RESULTS

All patients, whose ages ranged from 2 to 16 years, underwent craniotomy and excision of an AVM, which was supratentorial in 18 cases and infratentorial in 2. Patients in 11 cases underwent preoperative embolization, and all other patients underwent cerebral angiography prior to surgery, except for 2 patients who were urgently surgically treated because of low Glasgow Coma Scale scores and associated hematoma. Spetzler-Martin Grades I (3 cases), II (6), III (7), and IV (4) AVMs were represented in this series. Intraoperative Doppler ultrasound provided high-quality images in all cases and demonstrated the location, size, and flow characteristics of the AVM and any associated hematoma. Delayed postoperative cerebral angiography demonstrated successful AVM resection in all cases. An assessment of clinical outcomes revealed no new long-term neurological deficits at 3 months postoperatively.

CONCLUSIONS

Intraoperative Doppler ultrasonography is a reliable and useful tool for intraoperative localization and guidance for AVM resection in the pediatric population. When used in conjunction with neuronavigation equipment and modern microscopes, this technique has shown a very high complete resection rate with extremely low associated morbidity.

Indocyanine green videoangiography "in negative": definition and usefulness in spinal dural arteriovenous fistulae

PURPOSE

Indocyanine green videoangiography (IGV) has proven its effectiveness in the field of exovascular neurosurgery, both in the intracranial and spinal compartment, but is necessary to define a systematic process for the performance of the IGV to facilitate its interpretation during the procedure. We have defined and applied the concept of videoangiography "in negative" (INIGV) to spinal dural arteriovenous fistulae (dAVF) for the detection and treatment of arteriovenous shunts, so called because the first phase is performed with the vessel suggestive of being pathological occluded.

METHODS

A Pentero-operating microscope with near-infrared IGV-integrated system (Carl Zeiss Co., Germany) was used. At our institution, 24 patients were treated for a spinal dAVF between 1995 and 2011, only in the last 4 cases, INIGV was performed.

RESULTS

We describe the IGV in negative procedure and show the most illustrative cases. In all cases, the fistula occlusion was confirmed by postoperative selective digital subtraction angiography (DSA). INIGV demonstrate its capacity in detecting vessels not actually arterialized that should be respected and avoid some of the main limitations of the conventional IGV. This is a technical description about an Indocyanine green (ICG) videoangiographic procedure modification that is superior to merely performing ICG before and after clipping of a dAVF.

CONCLUSION

The INIGV results are rapid and easy to interpret procedure and provide great advantages to the dAVF treatment. Nevertheless, further studies are needed with a larger sample size to determine if INIGV may reduce the need to perform immediate postoperative DSA.

Intracranial pial arteriovenous fistula presenting with hemorrhage: a case report

Intracranial pial arteriovenous fistula (AVF) is a rare cerebrovascular malformation, which has a single or multiple arterial connections to a single venous channel without intervening nidus, and is different from arteriovenous malformation (AVM). We report on a case of a surgically treated pial AVF. A 15-year-old girl with an altered mental state was brought to our hospital. Computed tomography (CT) showed a subcortical hematoma of approximately 24 ml in her right temporal lobe. Cerebral angiography showed an AVF supplied by the right middle cerebral artery with early drainage into the Sylvian vein and the vein of Labbe. She underwent surgical treatment with feeding artery obliteration using a clip and hematoma removal. The patient was discharged without neurologic deficits. Despite the rarity of pial AVF, for correct diagnosis and treatment, neurosurgeons should recognize this condition. Pial AVF can be managed simply by disconnection of the shunt by surgery or endovascular treatment, and a good result can be achieved.

The role of intraoperative micro-Doppler ultrasound in verifying proper clip placement in intracranial aneurysm surgery

INTRODUCTION

Aneurysmal subarachnoid hemorrhage constitutes a clinical entity associated with high mortality and morbidity. It is widely accepted that improper clip placement may have as a result of incomplete aneurysm occlusion and/or partial or complete obstruction of an adjacent vessel. Various modalities, including intraoperative or postoperative digital subtracting angiography, near-infrared indocyanine green angiography, micro-Doppler ultrasonography (MDU), and neurophysiological studies, have been utilized for verifying proper clip placement. The aim of our study was to review the role of MDU during aneurysmal surgery.

METHODS

A literature search was performed using any possible combination of the following terms: "aneurysm," "brain," "cerebral," "clip," "clipping," "clip malpositioning," "clip repositioning," "clip suboptimal positioning," "Doppler," "intracranial," "microsurgery," "micro-Doppler," "residual neck," "ultrasonography," "ultrasound," and "vessel occlusion". Additionally, reference lists from the retrieved articles were reviewed for identifying any additional articles. Case reports and miniseries were excluded.

RESULTS

A total of 19 series employing intraoperative MDU during aneurysmal microsurgery were retrieved. All studies demonstrated that MDU accuracy is extremely high. The highest reported false-positive rate of MDU was 2 %, while the false-negative rate was reported as high as 1.6 %. It has been demonstrated that the presence of subarachnoid hemorrhage, specific anatomic locations, and large size may predispose to improper clip placement. Intraoperative MDU's technical limitations and weaknesses are adequately identified, in order to minimize the possibility of any misinterpretations.

CONCLUSION

Intraoperative MDU constitutes a safe, accurate, and low cost imaging modality for evaluating blood flow and for verifying proper clip placement during microsurgical clipping.

Index proposal and basic estimator study for quantification of oscillation of the secondary flow pattern in tortuous vessels

The development of atherosclerosis has been shown to correlate with regions of low wall shear stress and seemingly reduced mass transport. The local tortuosity of the arteries and local secondary flow oscillation also seem to be negatively correlated with the local occurrence of the disease. However there is currently no tool or physiological parameter that can be measured non-invasively to assess the local oscillation of the flow. Standard Colour Doppler imaging of secondary flow patterns during the blood pulse is studied and illustrated, and the local oscillation of the secondary flow pattern is proposed as an index, which could be an indicator of the likelihood of future disease development. Preliminary results are presented using a basic estimator developed for the proof of concept in the case of swirling flow, and based on colour-coded video signals collected in different configurations. In vitro results show that there is a correspondence between the Doppler patterns and the secondary flow patterns, the repeatability of the measures, and that the proposed index and its estimator reflect a joint influence of the local oscillation of the secondary flow pattern and of the flow rate. On another hand, while in vivo results still suffer from instabilities, noise and from scanners and processing limitations, they demonstrate that it is possible to use Colour Doppler imaging to image and characterize in vivo the secondary flow patterns and their oscillations non-invasively, and that it is possible for a trained clinician to perform manually such Doppler measurements for processing.

FLOW 800-assisted surgery for arteriovenous malformation

FLOW 800 is software for analytical colour visualisation and objective evaluation of fluorescence video obtained by microscope-integrated intraoperative indocyanine green fluorescence angiography. A 56-year-old male underwent surgical excision of a large complex arteriovenous malformation (AVM) of the right parietal region. FLOW 800 software was used to identify feeding arteries, arterialised veins and passing vessels. Complete excision of the AVM was achieved, confirmed by FLOW 800 and postoperative digital subtraction angiography. The role of FLOW 800, its applications and limitations in AVM surgery are discussed.

Intraoperative magnetic resonance imaging in the successful surgical treatment of an arteriovenous malformation--case report

A 44-year-old female presented with left occipital arteriovenous malformation (AVM) manifesting as sudden onset of severe headache. Magnetic resonance (MR) imaging and conventional angiography showed the left occipital AVM with hemorrhage. Intraoperative MR imaging (iMR imaging) and intraoperative time-resolved imaging of contrast-kinetics (iTRICKS) at 1.5 T revealed complete removal of the nidus of the AVM without conventional catheter angiography. Conventional catheter angiography is commonly used in preoperative and intraoperative examination of AVMs, and for documentation of the surgical outcome, but less-invasive techniques are desirable for both preoperative screening and intraoperative examination. iMR imaging with iTRICKS is less invasive and safer than conventional angiography for both brain tumor surgery and AVM surgery.

Indocyanine green videoangiography in the management of dural arteriovenous fistulae

OBJECTIVE

To evaluate the usefulness of indocyanine green (ICG) videoangiography in the operative management of dural arteriovenous fistulae (dAVFs).

METHODS

Intraoperative ICG videoangiography was used as a surgical adjunct in 25 patients with cranial and spinal dural arteriovenous fistulae to identify the fistula and verify its complete obliteration. The findings on ICG videoangiography were compared with intraoperative and/or postoperative imaging.

RESULTS

All dural arteriovenous fistulae were clearly identified by intraoperative ICG videoangiography and obliteration was documented in each case. Findings on ICG videoangiography correlated with intraoperative and/or postoperative imaging.

CONCLUSION

ICG videoangiography is a useful adjunct to the surgical management of dural arteriovenous fistulae for localization and confirmation of complete obliteration. The safety and ease of use make it an attractive modality. The surgeon can only evaluate what is visualized under the operating microscope and must therefore fully expose the venous drainage of the fistula to confirm obliteration.

Prospective evaluation of surgical microscope-integrated intraoperative near-infrared indocyanine green angiography during cerebral arteriovenous malformation surgery

OBJECTIVE

Microscope-integrated indocyanine green (ICG) fluorescence angiography is a novel technique in vascular neurosurgery with potential utility in treating arteriovenous malformations (AVMs).

METHODS

We analyzed the application of intraoperative ICG in 10 consecutive AVM surgeries for which surgical video was available. The ability to distinguish AVM vessels (draining veins, feeding and nidal arteries) from each other and from normal vessel was evaluated, and ICG angiographic findings were correlated with intra- and postoperative findings on digital subtraction angiography (DSA).

RESULTS

ICG angiography was found to be useful by the surgeon in 9 of 10 patients. In 8 patients, it helped to distinguish AVM vessels. In 3 of 4 patients undergoing a postresection injection, it demonstrated that there was no residual arteriovenous shunting. In 1 patient, it helped to identify a small AVM nidus that was otherwise inapparent within a hematoma. Intraoperative DSA showed residual AVM in 2 of 10 patients requiring further resection of AVM not visualized during surgery.

CONCLUSION

Microscope-integrated ICG angiography is a useful tool in AVM surgery. It can be used to distinguish AVM vessels from normal vessels and arteries from veins based on the timing of fluorescence with the dye. Our experience suggests that it is less useful with deep-seated lesions or when AVM vessels are not on the surface. ICG angiography complements rather than replaces DSA.

Spontaneous pial single-channel arteriovenous fistulae with angiographically occult small feeding arteries: case report

BACKGROUND

Pial single-channel arteriovenous (AV) fistulae are usually cured by interrupting only the feeding arteries identified in cerebral angiography.

CASE DESCRIPTION

A 27-year-old woman presented after 3 complex partial seizures due to a pial single-channel AV fistula with the varix located in the right temporal lobe. When all feeding arteries identified by preoperative cerebral angiography were temporarily occluded, varix blood flow was confirmed with Doppler ultrasonography. Many small feeding arteries were identified, and the varix was dissected and removed. The postoperative course was uneventful and postoperative cerebral angiography revealed no abnormal vascular lesions.

CONCLUSION

Pial single-channel AV fistulae are not always cured by interrupting only the feeding arteries identified in cerebral angiography and might require varix removal.

Intraoperative Ultrasonography of the Brain and Spine

Intraoperative ultrasonography can play a particularly useful role in facilitating surgery or guiding biopsies in the brain and spinal canal. Given the limited access that is frequently afforded to the operating surgeon, coupled with lesions that may be located in deep or seemingly inaccessible locations, sonography performed through tiny burr holes is useful for confirming location of lesions, guiding biopsy, and confirming extent of resection. In the spine, sonography is most helpful for confirming the precise location of intradural or extradural masses and guiding biopsies. In this review, we describe the technical requirements necessary for scanning the brain and spinal cord and suggest scanning techniques. The spectrum of pathological entities are illustrated along with potential pitfalls that the inexperienced operator is likely to encounter.

Intraoperative angiography for neurovascular disease in the prone or three-quarter prone position

BACKGROUND

Intraoperative angiography for neurovascular disease has gained wide acceptance as a useful tool. There are few published cases of intraoperative angiography performed in the prone or three-quarter prone position, and the transradial approach has not previously been described for this situation.

METHODS

We retrospectively reviewed our last 177 consecutive cases of intraoperative angiography performed for neurovascular disease. Of these cases, 21 were performed in the prone or three-quarter prone position. Two different approaches were used: (1) a previously described extended femoral sheath approach (13 cases) and (2) a newly described transradial approach (8 cases).

RESULTS

All 21 intraoperative angiograms were successfully completed in the prone or three-quarter prone position. This enabled us to make additional surgical adjustments when necessary or to conclude the operation. One complication, a dissection of the brachial artery, occurred during one intraoperative angiographic procedure.

CONCLUSIONS

Intraoperative angiography can be performed in the prone or three-quarter prone position with good efficacy and safety. The transfemoral route has the advantage of familiarity but has disadvantages of poor sterility at access site, possible kinking or thrombosis of the sheath, and possible skin injury while resting on the tubing during long procedures. The transradial route has advantages of continuous access to the entry site throughout the surgical procedure and ease of catheterization of vertebral arteries for occipital and suboccipital lesions. However, the transradial route has the disadvantage of working from an unfamiliar approach, especially for spinal arteriovenous malformations.

Intraoperative landmarking of vascular anatomy by integration of duplex and Doppler ultrasonography in image-guided surgery. Technical note

BACKGROUND

The integration of ultrasound technology into neuronavigation systems has recently been the subject of reports by several groups. This article describes our preliminary findings with regard to the integration of data derived from intraoperative duplex (color mode) and Doppler ultrasonography into a neuronavigational data set. It was the aim of the study to investigate (1) whether the intraoperative landmarking of vessels that are outlined with ultrasound technology is possible and (2) whether such a technique might be of clinical interest for neurosurgical interventions.

METHODS

The video image of an ultrasound plane (Toshiba, Powervision 6000 SSA-370A, Tokyo, Japan) was integrated into our neuronavigation system (VectorVision2, BrainLab, Heimstetten, Germany). For calibration of the ultrasound plane, an instrument adapter was fixed to the ultrasound probe and then calibrated using a special, predefined calibration phantom.

RESULTS

Accordingly, the system supported a combination of the ultrasound plane functionality with the preoperatively acquired neuronavigational data. The duplex and Doppler mode of the ultrasound system displayed the intraoperative vascular anatomy. Once a vessel was outlined during surgery, it could be landmarked by touching the navigation screen. These landmarks were integrated automatically into the neuronavigational data set and could be used to provide intraoperative image updates of the vascular anatomy. This technique was successful in 45 of 47 (95.7%) surgical interventions.

CONCLUSIONS

Both image-guided ultrasound and duplex-guided integration of vascular anatomy into the neuronavigational data set are technically possible. In the future, this technology may provide useful intraoperative information during surgery of complex cerebral pathologies.

Intraoperative Color Doppler Sonography in the Surgical Treatment of Perimedullary Arteriovenous Fistula-Case Report-

A 36-year-old female was treated for a perimedullary arteriovenous fistula (AVF) using intraoperative color Doppler sonography monitoring. Color Doppler sonography before interruption of the fistulous point clearly demonstrated an abnormal hyperechoic lesion. After interruption of the shunting point, the lesion had disappeared. Intraoperative angiography confirmed the disappearance of the perimedullary AVF. Intraoperative color Doppler sonography is a noninvasive, reliable, and cost-effective method for monitoring the effect of interruption on perimedullary AVF.

Intraoperative sonography of intracranial arteriovenous malformations: how we do it

OBJECTIVE

We have advanced the application of intraoperative neurosonography by combining gray scale sonographic imaging with pulsed wave Doppler and color flow Doppler imaging to guide and confirm resection of arteriovenous malformations of the brain. We want to share our technique with the imaging community.

METHODS

We present a review of our scan technique as it has evolved over the 3 years during which we have been assisting our neurosurgical team.

RESULTS AND CONCLUSIONS

Our experience has indicated that a combination of sonographic imaging and color and spectral Doppler imaging improves surgical resection of such lesions.

Intraoperative Doppler to Measure Cerebrovascular Resistance as a Guide to Complete Resection of Arteriovenous Malformations

OBJECTIVE:

Intraoperative color Doppler ultrasound has been used to locate arteriovenous malformations (AVMs). We describe the use of spectral Doppler to measure flow resistance and resistive index (RI) of vessels around the nidus to distinguish feeding arteries from en passant and normal vessels. This is particularly helpful in small AVMs and aids in the identification of normal vessels and completeness of resection by ruling out persistent low RI flow.

METHODS:

Seven patients with AVMs underwent resection. Spectral Doppler applied to the vessels in proximity to the AVM, along with calculated RI, was used to identify feeding arteries and draining veins. After presumed surgical resection of the AVM, pre-resection and postresection RIs were compared to identify residual AVM. Postoperative angiography was performed in all seven patients to confirm complete resection of the AVM.

RESULTS:

The mean pre-resection RI of vessels feeding the AVM was 0.34 (±0.01). In five patients without residual nidus on the basis of postresection color Doppler and postoperative angiogram, the postresection RI was 0.62 (±0.04). In two patients, the postresection scan identified a nidus with persistent low RI flow. Once residual AVM was resected, the RI became significantly higher. A postoperative angiogram confirmed complete resection of the AVM in all patients.

CONCLUSION:

Intraoperative duplex Doppler allowed more accurate localization of the AVM nidus. RI of the vessels around the AVM helped to distinguish vessels feeding the AVM from en passant vessels. Furthermore, comparison of pre-resection and postresection RI accurately indicated the completeness of resection.

Usefulness of color Doppler ultrasound in the management of a spinal arteriovenous fistula

BACKGROUND

While color Doppler ultrasonography and microvascular Doppler recordings have been used intraoperatively for spinal cord vascular malformations, they have not been employed for similar spinal cord lesions preoperatively.

CASE DESCRIPTION

We report the usefulness of color Doppler ultrasonography through a lumbar laminectomy defect in the management of a spinal arteriovenous fistula.

CONCLUSION

Color Doppler ultrasonography should be considered for spinal lesions in which a laminectomy defect is present.

Hemostasis of punctured vessels using Doppler-guided high-intensity ultrasound

The use of Doppler ultrasound was investigated to determine if it would aid in guiding the application of high-intensity focused ultrasound (HIFU) to stop bleeding from punctured vessels. Major vessels (abdominal aorta, illiac, carotid, common femoral and superficial femoral arteries and the jugular vein) were surgically exposed, punctured and treated in anesthetized pigs. Treatment was applied when the Doppler sounds indicated the focus coincided with the bleeding site. In 89 treatment trials, the average time to achieve major hemostasis (a point where bleeding was reduced to a level of only oozing) was 8 s, and for complete hemostasis was 13 s. These times were significantly shorter than those of an identical former study in which only visual guidance was used. In that study, the average times for major and complete hemostasis were 40 and 62 s, respectively. The advantage of Doppler guidance in applying HIFU in treating bleeding vessels was demonstrated.

Intraoperative color-coded duplex sonography for localization of a distal middle cerebral artery aneurysm: technical case report

OBJECTIVE AND IMPORTANCE

We describe the surgical treatment of a small, distal, middle cerebral artery (MCA) aneurysm, performed using intraoperative color-coded duplex sonography for localization.

CLINICAL PRESENTATION

A 55-year-old man presented with a sudden intense headache. Computed tomographic scans revealed a subarachnoid hemorrhage. Angiography demonstrated two MCA aneurysms, one arising from the proximal bifurcation of the right MCA and the other from its distal bifurcation.

TECHNIQUE

On Day 1, the proximal MCA aneurysm was clipped via the standard transsylvian approach. The distal MCA aneurysm was identified with the aid of color-coded duplex sonography and was successfully clipped with minimal additional dissection of the sylvian fissure.

CONCLUSION

Color-coded duplex sonography provides a two-dimensional image of the brain parenchyma and color-coded flow imaging of cerebral vessels in real time. It may be used for rapid intraoperative localization of small, distally located, cerebral aneurysms.

Color Doppler ultrasound imaging in the emergency management of an intracerebral hematoma caused by cerebral arteriovenous malformations: technical case report

OBJECTIVE AND IMPORTANCE

Ruptured arteriovenous malformations (AVMs) are important causes of spontaneous intracerebral hemorrhages. This is a report of emergency hematoma removal, avoiding damage to the nidus of the AVM, using intraoperative color Doppler imaging.

CLINICAL PRESENTATION

A 38-year-old woman suddenly presented with coma. The patient underwent emergency surgery immediately after admission, without preoperative angiographic examination, because of progressive neurological deterioration caused by a massive hematoma in the right basal ganglia, as diagnosed with computed tomographic scanning.

INTERVENTION

A right frontotemporoparietal craniotomy was performed. Intraoperative ultrasound imaging with a color Doppler system (EUP-NS32, 5 MHz; Hitachi Medical, Tokyo, Japan) clearly demonstrated a nidus complex in the hematoma. Based on the imaging, effective decompression of the hematoma was performed without damage to the AVM complex.

CONCLUSION

Color Doppler imaging (with real-time availability) of an atypical hematoma provided significant information on the vascular lesion causing the hematoma and could reduce the surgical risks during emergency evacuation of large intracerebral hemorrhages resulting from ruptured AVMs.

Intraoperative color duplex sonography of basal arteries during aneurysm surgery

This prospective study aimed at (1) characterizing the duplex sonographic appearance of cerebral aneurysms, (2) visualizing their location, and (3) ensuring the complete occlusion of the aneurysm as well as the patency of the basal arteries during aneurysm surgery. During 9 months 30 craniotomies for aneurysm clipping in 29 patients were monitored intraoperatively by B-mode and color-coded duplex sonography. Following craniotomy the aneurysm and the preaneurysmatic and postaneurysmatic arteries were sonographically visualized before and after clipping and removal of the spatulas. Twenty-seven (90%) of 30 aneurysms appeared as a hypoechoic structure. Together with the typical dichromatic picture in the color mode and the characteristic bidirectional flow pattern in the duplex mode, 29 (97%) of 30 aneurysms were identified and localized anatomically correctly. Eighty (99%) of 81 relevant vessels were visualized and measured with the Doppler mode. After clipping, flow was detectable in all major arteries except 3 middle cerebral artery (MCA) branches. In 1, occlusion was confirmed by postoperative angiography. In the other 2, early postoperative computed tomography showed an infarction of the corresponding MCA territories. This study demonstrated the potential of color duplex sonography to visualize and characterize cerebral aneurysms and adjacent basal arteries before and after clipping. It offers a noninvasive intraoperative method to control the patency of basal arteries and complete occlusion of the aneurysm.

Visualisation of intracranial aneurysms by transcranial duplex sonography

We examined 72 patients with 89 angiographically confirmed intracranial aneurysms, using transcranial colour-coded duplex sonography (TCCD) to determine the location and size of the aneurysm. The patients were admitted for coil embolisation of their aneurysm following subarachnoid haemorrhage or because of a cranial nerve palsy. Using a 2/2.25 MHz transducer, 42 aneurysms (47%) were seen satisfactorily through the temporal bone window or foramen magnum. In 24 cases (27%) image quality was insufficient as a result of a poor bone window, of the aneurysm having a diameter of less than 6 mm or of its being in an unfavorable location. In 23 other cases (26%) it was not possible to detect the aneurysm. Thrombosed structures could be demonstrated using TCCD in 8 of 12 giant intracavernous or basilar artery aneurysms, and in 15 of 19 aneurysms treated by platinum coil embolisation. TCCD offers a noninvasive method for monitoring progressive intra-aneurysmal thrombosis following coil embolisation and for follow-up of patients with untreatable fusiform aneurysms, should this be required. Detection of small aneurysms is limited by spatial resolution and insonation angles.

Persistent feeding arteries to angiographically completely embolized arteriovenous malformation demonstrated by intraoperative color-flow Doppler testing: report of two cases

Two cases of arteriovenous malformation (AVM) treated preoperatively by endovascular embolization that appeared to be completely occluded after embolization are presented. Seven and 12 days later, respectively, these patients underwent resection of their AVM. At the time of surgery, intraoperative color-flow Doppler studies revealed persistent feeding arteries to an active residual nidus of the AVM. The significance of this finding is presented in light of previous published literature.

Demonstration of giant MCA aneurysm by transcranial duplex sonography and color Doppler imaging

Transcranial color Doppler sonography is a new diagnostic technique which allows real-time, color-coded imaging of basal cerebral arteries, with simultaneous demonstration of parenchymal structures in the B-mode scan. With this technique we were able noninvasively to show a giant fusiform aneurysm of the middle cerebral artery (MCA) in an 11-year-old boy. Transcranial color Doppler sonography through the intact temporal bone demonstrated the size and location of the aneurysm and provided real-time imaging of the pulsating intra-aneurysmal flow. Additionally, duplex sonographic measurements of intravascular flow velocities within the aneurysm and the feeding and draining artery were possible. Postoperatively, patency of the MCA with reduced flow velocities after excision of the aneurysm could be shown. This is the first transcranial color Doppler report in a patient with an intracerebral aneurysm. In our opinion, transcranial color Doppler sonography offers new diagnostic possibilities in patients with cerebrovascular disorders.

Transcranial color-coded real-time sonography in adults

We investigated the diagnostic potential of transcranial color-coded real-time sonography in 52 individuals using a phased-array ultrasound system with color-coded blood flow representation. Ultrasound scans in the axial and coronal planes were feasible through temporal acoustic bone windows in 49 subjects, enabling depiction of the main parenchymal and vascular structures as well as the ventricular system. Color-coded representation of blood flow in the cerebral vessels allowed unequivocal identification of the circle of Willis within the anatomic black-and-white B-mode image of the parenchymal structures. In Doppler mode, vascular blood flow phenomena may be analyzed semiquantitatively using the Doppler frequency spectrum. This noninvasive, serially applicable, mobile beside method may complement conventional neuroradiologic imaging methods, allowing on-line studies of functional processes within the adult brain.

Cranial Doppler ultrasonography correlates with criteria for ventriculoperitoneal shunting

Using pulsed Doppler ultrasound through the sonic window of the anterior fontanelle in infants, 46 children with ventriculomegaly had sequential evaluations of Resistive Index for comparison with the need for ventriculoperitoneal shunting. Hydrocephalus was associated with myelomeningocele in 17 patients and posthemorrhagic, postmeningitic, or congenital hydrocephalus accounted for the rest. The Resistive Index was obtained by dividing the difference between the peak systolic and end diastolic frequencies by the systolic frequency. Criteria for shunting included massive ventriculomegaly, increasing ventriculomegaly with an abnormal increase in head circumference, and clinical evidence of symptomatic hydrocephalus. Those patients requiring shunts had a Resistive Index of 84 +/- 13% prior to shunting. The Resistive Index fell to 72 +/- 11% postshunting with the difference being statistically significant at p less than 0.001. Moreover, the postshunting values compared favorably to data on 29 normal newborns, having Resistive Indices of 71 +/- 7% and to the Resistive Indices of three patients never shunted who had values of 74%, 66%, and 71%. Variations included primarily low Resistive Indices in myelomeningocele patients whose ventricles were decompressed by the leaking spinal lesions. Resistive Index used in conjunction with clinical observations may be extremely helpful not only in predicting the need for ventriculoperitoneal shunt, but also in evaluating children suspected of shunt malfunctions.