Microvascular Doppler Sonography Research Articles

Laser speckle contrast imaging versus microvascular Doppler sonography in aneurysm surgery: A prospective study

ObjectiveThis study aimed to compare microvascular Doppler sonography (MDS) and laser speckle contrast imaging (LSCI) for assessing vessel patency and aneurysm occlusion during microsurgical clipping of intracranial aneurysms. MethodsMDS and LSCI were used after clip placement during six neurovascular procedures including six patients, and agreement between the two techniques was assessed. LSCI was performed in parallel or right after MDS evaluation. The Doppler response was assessed through listening while flow in the LSCI videos was evaluated by three blinded neurovascular surgeons after the surgery. Statistical analysis determined the agreement between the techniques in assessing flow in 18 regions of interest (ROIs). ResultsAgreement between MDS and LSCI in assessing vessel patency was observed in 87 % of the ROIs. LSCI accurately identified flow in 93.3 % of assessable ROIs, with no false positive or negative measurements. Three ROIs were not assessable with LSCI due to motion artifacts or poor image quality. No complications were observed. ConclusionsLSCI demonstrated high agreement with MDS in assessing vessel patency during microsurgical clipping of intracranial aneurysms. It provided continuous, real-time, full-field imaging with high spatial resolution and temporal resolution. While MDS allowed evaluation of deep vascular regions, LSCI complemented it by offering unlimited assessment of surrounding vessels.

Insufficient Closing Forces of Yasargil Titanium Clips in Two Small Aneurysms Detected with Intraoperative Indocyanine Green Videoangiography.

Aneurysm clips must have adequate closing forces because residual blood flow in clipped aneurysms may result in aneurysm recurrence. Such flow can be intraoperatively detected by visual inspection, microvascular Doppler sonography, indocyanine green videoangiography (ICG-V), angiography, and puncture. We present two patients with ruptured very small middle cerebral artery aneurysms (3 and 2.9 mm). The necks of both aneurysms were microsurgically clipped with Yasargil aneurysm clips without any complications. In both aneurysms, visual inspection suggested complete occlusion, but ICG-V showed persistent residual blood flow between the middle parts of the clip blades.The first patient was treated with a 5.4-mm FT744T clip (closing force of 1.47 N). After the ICG-V finding, a second 3.9-mm FT714T clip (closing force of 1.08 N) was placed on the tips of the already implanted clip to increase the closing forces. Subsequent ICG-V did not show any further residual blood flow. In the second patient, the aneurysm was clipped with an 8.0-mm FE764K clip (closing force of 1.77 N). Intraoperative ICG-V showed persistent residual blood flow within the aneurysmal dome despite complete closure of the clip. The clip was repositioned closer to the parent vessel. Consecutive ICG-V did not show any residual blood flow. Visually undetected incomplete aneurysm occlusion can be revealed with ICG-V. In very small aneurysms, standard closing forces of clips may not be sufficient and complete closure of the clip branches should be intraoperatively validated with ICG-V.

Intraoperative Combined Use of Somatosensory Evoked Potential, Microvascular Doppler Sonography, and Indocyanine Green Angiography in Clipping of Intracranial Aneurysm.

BackgroundThe aim of this study was to evaluate the effect of combining application of somatosensory evoked potential (SEP), microvascular Doppler sonography (MDS), and indocyanine green angiography (ICGA) in intracranial aneurysm clipping surgery.Material/MethodsA total of 158 patients undergoing an intracranial aneurysm clipping operation were recruited. All patients were evaluated with intraoperative SEP and MDS monitoring, and 28 of them were evaluated with intraoperative combined monitoring of SEP, MDS, and ICGA.ResultsThe SEP waves dropped during temporary occlusion of arteries in 19 cases (12.0%), and returned to normal after the clips were repositioned. After aneurysms were clipped, the vortex flow signals were detected by MDS in 6 cases. The aneurysm neck remnants were detected by ICGA in 2 cases of olfactory artery (OA) and in 1 case of middle cerebral artery (MCA), which disappeared after the clips were repositioned. Postoperative CTA or DSA showed that aneurysms were clipped completely and parent arteries and perforating vessels were patent. GOS at 1 month after the surgery was good in 111 cases (70.3%), mild disability in 22 cases (13.9%), severe disability in 14 cases (8.9%), vegetative state in 5 cases (3.2%), and death in 6 cases (3.8%).ConclusionsIntraoperative combining application of SEP, MDS, and ICGA can reduce brain tissue ischemia and damage and disability and mortality rate after effective clipping of intracranial aneurysms, thereby improving surgical outcomes.

Prevention of ischemic complications during aneurysm surgery.

Ischemic complications during aneurysm surgery are a frequent cause of postoperative infarctions and new neurological deficits. In this article, we discuss imaging and neurophysiological tools that may help the surgeon to detect intraoperative ischemia. The strength of intraoperative digital subtraction angiography (DSA) is the full view of the arterial and venous vessel. DSA is the gold standard in complex and giant aneurysms, but due to certain disadvantages, it cannot be considered standard of care. Microvascular Doppler sonography is probably the fastest diagnostic tool and can quickly aid diagnosis of large vessel occlusions. Intraoperative indocyanine green videoangiography is the best tool to assess flow in perforating and larger arteries, as well as occlusion of the aneurysm sac. Intraoperative neurophysiological monitoring with somatosensory and motor evoked potentials indirectly measures blood flow by recording neuronal function. It covers all causes of intraoperative ischemia, provided that ischemia occurs in the brain areas under surveillance. However, every method has advantages and disadvantages. No single method is superior to the others in every aspect. Therefore, it is very important for the neurosurgeon to know the strengths and weaknesses of each tool in order to have them available, to know how to use them for each individual situation, and to be ready to apply them within the time window for reversible cerebral ischemia.

Neuronavigated microvascular Doppler sonography for intraoperative monitoring of blood flow velocity changes during aneurysm surgery – A feasible monitoring technique

Introduction and aim of the studyThe intraoperative microvascular Doppler sonography (iMDS) is a well-established tool in vascular surgery for blood flow velocity (BFV) monitoring, capable of detecting vessel occlusion. However, identification of subtotal vessel compromise is more difficult, since the measured BFV may substantially vary with changing insonation angles and insonated vessel segments. To keep these parameters constant we combined neuronavigation with iMDS (niMDS). The question was if niMDS allows the detection of subtotal vessel compromise in aneurysm surgery. MethodsDuring surgery, the 3-dimensional reconstruction of the CT-angiography, which was obtained routinely prior to surgery, was displayed by the neuronavigational system. Prior to clipping, neuronavigation was used to define target point and trajectory, which, by coupling the neuronavigational pointer with the Doppler probe, correspond to the insonated vessel segment and the insonation angle. After clipping, for each vessel segment, the same trajectory was used for all consecutive measurements. The mean BFVs pre- and post-clipping were documented. ResultsWe performed 82 BFV-measurements in 39 aneurysm surgeries. Mean deviation between pre- and post-clipping BFV values was 2.12cm/s. There was a significant correlation between the mean BFV values before and after clipping (r=0.45 [95% CI 17–66%]; p=0.002). One patient experienced new neurological deficits due to occlusion of a perforating vessel that was not insonated. ConclusionThe study could not answer the question if niMDS can detect BFV changes after clipping indicating vessel compromise, as no subtotal vessel occlusion occurred in the 39 operations. However, we proofed that niMDS-measured BFVs only varied minimally in uncompromised vessels pre- and post-clipping, suggesting that vessel compromises might be easily detected during aneurysm surgery.

Evaluation of Esophagogastric Varices after Adult-to-Adult Living Donor Liver Transplantation Using a Left Lobe Graft

Background: There is little information on whether living donor liver transplantation (LDLT) reduces the supply of blood to esophagogastric varices. The aim of the present study was to assess the effects of LDLT on esophagogastric varices using both endoscopy and transendoscopic microvascular Doppler sonography (EMDS). Patients and Methods: 16 LDLT recipients were enrolled in the present study. Esophagogastric varices were assessed by endoscopy before and after LDLT. Direct measurement of variceal blood velocity was performed using EMDS in 12 of the 16 patients, and portal vein pressure before and after graft implantation was measured in 10 of them. Results: The median interval between LDLT and endoscopic examination was 129 days (range 20-624). Endoscopy demonstrated improvement of esophageal varices in 15 patients and of gastric varices in 4 of 5 patients assessed. The mean blood flow velocity in esophageal varices after LDLT was significantly lower than that before LDLT (8.8 w 3.6 vs. 0.9 w 1.2 cm/s, p < 0.001). The mean portal vein pressure did not decrease significantly after LDLT in comparison with that before LDLT (from 25.2 w 5.2 to 23.1 w 3.6 mm Hg, p = 0.22). Conclusion: Although portal vein pressure does not decrease immediately after left lobe LDLT, esophagogastric varices are ameliorated after a few months, and variceal blood flow velocity is reduced in almost all patients. i 2014 S. Karger AG, Basel

Microsurgical treatment of intracranial thrombotic giant aneurysms( report of 11 cases)

Objective To study the clinical features and surgical management of intracranial thrombotic giant aneurysms.Methods A retrospective study was performed for 11 patients with intracranial thrombotic giant aneurysms.The clinical presentation, clinical classification, surgical approaches and therapeutic efficacy were reviewed.Results The treatment included thrombectomy - aneurysm clip reconstruction in 9 cases, thrombectomy - aneurysm isolate in 1, and cervical internal carotid artery ligation in 1.The postoperative DSA or CTA showed that complete angiographic obliteration was achieved in 10 cases.Follow - up period was from 3 months to 6 months, the clinical outcomes of these patients were evaluated by Glasgow Outcome Scale grades.GOS of 8 cases were improved.There were minor deficit in 1 case, major deficit in 1 and one death.Conclusions The surgical treatment for intracranial thrombotic giant aneurysms is very difficult.It is a good method to occlude the parent artery temporally, eliminate intraaneurysmal thrombus and reconstruct parent artery.Intraoperative microvascular Doppler sonography (MVD) monitoring is helpful. Key words: Intracranial aneurysm; Thrombus; Microsurgical clipping; Thrombectomy

Reliability of Near-Infrared Angiography and Micro-Doppler Sonography for Evaluating Microvascular Anastomoses

Intraoperative fluorescence angiography has been reported to be a promising method, with rapid and high-quality image production at low cost when used for the detection of microvascular complications. The purpose of this study was to evaluate the reliability of intraoperative near-infrared indocyanine green angiography compared with microvascular Doppler testing in a standardized model in the rat with different vessel patencies. The carotid, aorta, and femoral vessels of 23 Wistar rats were used. Indocyanine green angiography and microvascular Doppler sonographic testing were performed to assess microanastomosis with a vessel patency randomly narrowed at the anastomosis to an outer patency of 100, 75, 50, 25, and 0 percent. A total of 424 investigations were performed for 68 anastomoses, including both indocyanine green videoangiographic and microvascular Doppler sonographic examinations. The overall sensitivity and specificity of the microvascular Doppler sonographic testing at different degrees of stenoses were 100 and 86.9 percent, respectively. The positive predictive value for all observations was 95.8 percent, and the corresponding negative predictive value was 100 percent. Indocyanine green angiography revealed an overall sensitivity of 95.3 percent and a specificity of 100 percent. The positive predictive value for these observations was 100 percent, and the negative predictive value was 84 percent. Indocyanine green angiography and microvascular Doppler sonography are quick and reliable methods for assessing blood flow in vessels in the laboratory model. The combined use of indocyanine green angiography and microvascular Doppler sonography can increase the accuracy of assessment of microvascular anastomoses intraoperatively. Indocyanine green can be used first, but followed by the microvascular Doppler in cases of a negative result to maximize accuracy.

Discussion: Reliability of Near-Infrared Angiography and Microvascular Doppler Sonography for Evaluating Microvascular Anastomoses

Sacramento, Calif. From the Division of Plastic Surgery, University of California, Davis. Received for publication June 3, 2010; accepted June 7, 2010. Disclosure:The author has no financial interests in any of the products, devices, or drugs mentioned in this Discussion or in the article being discussed. Lee L. Q. Pu, M.D., Ph.D., Division of Plastic Surgery, University of California, Davis, 2221 Stockton Boulevard, Suite 2123, Sacramento, Calif. 95817, [email protected]

Near-infrared indocyanine green videoangiography versus microvascular Doppler sonography in aneurysm surgery

The quality of surgical treatment of intracranial aneurysms is determined by complete aneurysm occlusion and restoration of flow in the parent, branching and perforating vessels. In postoperative digital subtraction angiography (DSA), unexpected aneurysm residuals and vessel occlusions are frequently detected. Here, the value of two nearly noninvasive and cost-effective techniques for intraoperative flow evaluation (near-infrared indocyanine green video angiography (ICG-VA) and microvascular Doppler sonography (mDs)) is investigated in a prospective study. Over a period of 10 months, the authors surgically clipped 50 aneurysms under intraoperative pre- and post-clipping evaluation of flow in the parent, branching and perforating vessels and the aneurysm sack by the two techniques. Intraoperative applicability of each technique was compared to each other and to postoperative digital subtraction angiography as standard evaluation technique. Forty-five aneurysms were totally occluded without vessel compromise (90%). Intraoperatively, ICG-VA was considered useful in 43 cases (86%) and mDs in 44 cases (88%), respectively. Both techniques could compensate each other's weak points to a certain degree; but two branch occlusions (4%) and three neck remnants (6%) were revealed by postoperative DSA. Both techniques have specific drawbacks that could be compensated by each other, to a certain extent. Intraoperatively, ICG-VA and mDs should not be considered competitive, but complementary. This study implicates that the combination of both applications on a routine basis assures the quality of aneurysm surgery by nearly noninvasive and cost-effective techniques. However, DSA remains the gold standard for evaluation of aneurysm occlusion.

Microsurgically Induced Aneurysm Models in Rats, Part II: Clipping, Shrinking and Micro-Doppler Sonography

To adapt to the changed approach in the treatment of aneurysms, the authors have developed three different experimental aneurysm models for teaching clipping, microvascular Doppler sonography and shrinking. 39 microaneurysms were created in 22 animals in three different locations at the carotid, femoral and iliac arteries and treated by neurosurgical clipping. Additionally, shrinking was accomplished in selected cases. Microvascular Doppler sonography with a 20-MHz microprobe was performed prior to and after clipping to assess the achieved result of the clipping manoeuvre. Multiple clip applications in different techniques were performed for optimisation of clip placement and additional training. All created aneurysms could be clipped successfully. The mean duration for clipping and control of clipping results by the micro-Doppler was 8:51+/-4:41 minutes at all aneurysms. The aneurysm clip was repositioned in 16 of 39 (41%) cases, on the basis of the Doppler findings in 14 aneurysms (36%). A relevant stenosis was detected in 10 (25.7%) and incomplete occlusion in 4 (10.2%) attempts. In one aneurysm vasospasm was detected at the distal part of the parent artery. Complete clipping was achieved in all cases. During the entire procedure three unexpected complications involving rupture and bleeding impeded the training. Surgically induced aneurysms in rats allow the possibility of multiple clipping, shrinking and micro-Doppler sonography for the simulation of aneurysm treatment.

Image-Guided Microneurosurgical Management of Small Arteriovenous Malformation: Role of Neuronavigation and Intraoperative Doppler Sonography

The goal of this study was to evaluate the efficacy and reliability of neuronavigation and intraoperative microvascular Doppler sonography (MDS) for identifying afferent (feeding) and efferent (draining) vessels as well as for controlling the totality of the surgical resection of arteriovenous malformations (AVMs). Between June 2000 and November 2005, twenty-five patients with small arteriovenous malformations (grades I-III) underwent microsurgical removal at our institution. A passive-marker-based neuronavigation system (Brain Lab, Munich, Germany), and an intraoperative MDS (Multi Dop X system, DWL, Germany) were used in this surgery. Blood flow velocities (BFV) in afferent and efferent vessels were recorded before and after removal of AVM. The preoperative neurological status and postoperative outcome were recorded. Patient follow-up monitoring ranged from 4 months to 3 years (mean: 16 months). The calculated registration accuracy of the neuronavigation computer ranged between 0.2-1.7 mm (mean: 1.1 mm). Before AVM removal the mean BFV of afferent vessels was 56.5+/-13.4 (28-98 cm/s) and the PI varied by 0.40+/-0.11 (0.25-0.66), after AVM removal these values reduced to 4.8+/-0.8 cm/s and 0.26+/-0.05, respectively. Similarly, before AVM removal, the mean BFV of efferent vessels was 13.5+/-4.5 (4-20 cm/s) and PI was 0.4+/-0.2 (0.34-0.56), after AVM removal both BFV and PI were not recorded. Complete removal of the AVMs was accomplished in 24 (96%) out of 25 patients which was confirmed with postoperative digital subtraction angiography (DSA). While there was no mortality, three patients (12%) had a worsening in their neurological status after surgery. Image-guided microneurosurgery with intraoperative MDS is a safe, effective, and reliable method for identifying the afferent and efferent vessels and for confirming the complete resection of AVMs. These benefits of image-guided microsurgery were most apparent for small, deep-seated AVMs that were not visible on the surface of the brain. In addition these techniques reduce the operative time and blood loss during AVM resection.

Intraoperative Microvascular Doppler Sonography in Aneurysm Surgery

The goal of this study was to evaluate the efficacy and reliability of intraoperative microvascular Doppler sonography (MDS) for the assessment of cerebral haemodynamics in aneurysm surgery. For 40 patients (21 men, 19 women, mean age 54.0 years, range 23-73 years) who underwent surgery for the treatment of 48 intracranial aneurysms, microvascular Doppler sonography with a 20-MHz microprobe was used before and after clip application, to confirm the complete obliteration of the aneurysm. Postoperative angiography was performed to assess the complete occlusion of the aneurysm and the patency of adjacent vessels. The findings of MDS were analysed and compared with the postoperative angiography. A 1-mm diameter microprobe was able to insonate all vessels of the circle of Willis and their major branches and perforating arteries were reliably insonated. The aneurysm clip was repositioned on the basis of the MDS findings in 12 out of 48 patients (25%). For 9 aneurysms (18.7%) MDS exposed a relevant stenosis of an adjacent vessel induced by clip positioning that had escaped detection by visual inspection. Clip repositioning resulted in complete occlusion of the aneurysms in 7 of 9 cases (14.5%). In two cases, additional wrapping became necessary as it was not possible to achieve complete clipping. The mean duration of MDS investigations was 5.3 minutes. There were no complications of intraoperative MDS probe use. Intraoperative MDS should be used routinely in cerebral aneurysm surgery, especially for large, complicated and giant aneurysms. Intraoperative MDS is a feasible, safe, and very reliable technique in aneurysm surgery. This technique is a valuable tool, in many instances, in place of intraoperative angiography for the surgical treatment of aneurysms.

無症候性未破裂脳動脈りゅうの治療方針と治療成績

There are many studies about asymptomatic unruptured cerebral aneurysms (AUAn), but we still have no evidence for those treatments. We report the management and treatment results for patients with AUAn in our department. In principle, the decision to operate for AUAn was based on the guideline of the Japanese Society for Detection of Asymptomatic Brain Diseases. As regards informed consent, hemorrhage risk of AUAn was explained with the use of a table showing lifetime risk for patients with AUAn. Intraoperative digital subtraction angiography (DSA) and microvascular Doppler sonography had been routinely utilized since May 1997 in surgical clipping. A portable DSA unit (Siremobil 2000, SIEMENS) was used for intraoperative DSA. We reviewed clinical features of 88 cases with 111 AUAns (30 males, 58 females, 63 years old±11 years) that were diagnosed and underwent angiography between January 1992 and July 2003. Fifty-one cases (58%) were treated, and 37 cases (42%) were untreated. Fifty-five aneurysms were treated with clipping and 1 aneurysm was treated with endovascular coil embolization. By introduction of informed consent with the guideline and lifetime risk for AUAn, the patients who did not choose an operation had increased. Moreover, the patients aneurysmal size under 4mm in diameter and the patients aged over 70 years had tended to follow up without surgery. Of the 28 aneurysms evaluated by intraoperative DSA, there was no complication with the technique of angiography. After introduction of intraoperative DSA and microvascular Doppler sonography, the morbidity had decreased from 15.4% to 7.1%. Informed consent with the guideline and lifetime risk for AUAn is useful whether patients choose an operation or not. We believe the use of intraoperative DSA and microvascular Doppler sonography is effective because it improves the result of clipping.

ＥＣ‐ＩＣ ｂｙｐａｓｓ術後の血行評価 Ｍｉｃｒｏｖａｓｃｕｌａｒ Ｄｏｐｐｌｅｒを用いたｄｏｎｏｒ ＳＴＡの経皮的血流評価法

To examine flowdynamic change after superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery, we measured the pulsatility index (PI) and end-diastolic blood flow velocity (Vd) of the donor STA by percutaneous direct microvascular Doppler sonography. In 63 patients (5-76 y/o) who had received STA-MCA bypass surgery for either ischemic stroke (11 cases), supportive therapy before parent artery occlusion in the treatment of internal carotid giant aneurysm (3 cases), or moyamoya disease (49 cases) (total 96 sides of STA), PI was 1.01±0.41 and Vd was 18.9±8.4 cm/sec. When compared to normal volunteers (6-76 y/o, 70 sides of STA) (PI: 1.96±0.63 and Vd: 5.6±2.5 cm/sec), PI decreased and Vd increased after STA-MCA bypass with high statistical significance (p<0.0001 and p<0.0001, respectively). Low PI and high Vd indicate that STA flow has changed from extracranial flow to intracranial flow. STA flowdynamics can be quantitatively assessed by measuring PI and Vd of the donor STA. This new bedside method is easy, noninvasive and useful to identify functional patency of the STA-MCA bypass.

Evaluation of a non-shunting operation by measurement of the blood flow velocity using transendoscopic microvascular Doppler sonography for esophageal and gastric varices

The purpose of this study was to evaluate whether transendoscopic microvascular Doppler sonography (EMDS) is useful to analyze Hassab's operation and esophageal transection (non-shunting operation) which are effective for patients with esophagogastric varices. Twenty patients with esophagogastric varices were examined. Before the operation, we examined the conditions of the esophagogastric varices and measured the velocity of the varices with EMDS. The blood flow velocity in the largest varices (F3) was significantly higher than that in the straight varices (F1). After the operation, the esophageal and gastric variceal blood flow velocities were markedly decreased in 15 patients. In five of the patients who received Hassab's operation, the esophageal variceal form and blood flow velocity still remained. After endoscopic injection sclerotherapy, the velocity and form were completely resolved. The non-shunting operation is effective therapy in the esophageal and gastric varices. It is concluded that EMDS is a non-invasive method and it appears to be very useful for the evaluation of the non-shunting operation.

A tentorial dural arteriovenous fistula successfully treated with interruption of leptomeningeal venous drainage using microvascular doppler sonography: Case report

BACKGROUND Complete interruption of a dural arteriovenous fistula (DAVF) has been confirmed intraoperatively by visual inspection and intraoperative angiography. To confirm complete interruption of the shunt flow during the surgical treatment of a tentorial DAVF, we used intraoperative microvascular doppler monitoring. CASE DESCRIPTION A 71-year-old man suffered from severe subarachnoid hemorrhage. Angiography showed a tentorial DAVF with pure leptomeningeal drainage associated with a venous pouch. After the patient’s neurologic condition had improved, he underwent interruption of the draining vein via a right suboccipital approach. An arterialized drainage vein was easily identified by applying the microvascular doppler probe to the shunting vessels and was completely obliterated by clipping. There were no complications associated with use of the microvascular doppler. The postoperative course was uneventful and follow-up angiography showed complete obliteration of the DAVF. CONCLUSION Intraoperative microvascular doppler monitoring is a useful technique not only for evaluating arterialized leptomeningeal drainage veins but also for confirming the complete obliteration of these vessels.

Practicability of intraoperative microvascular Doppler sonography in aneurysm surgery.

Inadvertent narrowing of parent or branching vessels is one major cause of unfavorable outcome from aneurysm surgery. Intraoperative micro-Doppler sonography of arterial brain vessels during surgery for cerebral aneurysms of the anterior circulation was performed in 50 patients and compared retrospectively with 50 patients, who were operated upon without micro-Doppler sonography. Intraoperative micro-Doppler sonography demonstrated the need for repositioning of the clip in 12 instances. Outcome after surgery with micro-Doppler sonography appeared slightly better than without. Micro-Doppler sonography is concluded to be a practicable adjunct to routine aneurysm surgery.

Intra-operative measurement of cortical arterial flow volumes in posterior circulation using Doppler sonography

Little has been reported on the flow volume of cortical arteries in the posterior circulation. During craniotomy in 28 patients, we measured the flow velocity of the arteries using microvascular Doppler sonography and recorded their arterial radii and the insonation angle. The flow velocities and radii were 25.7 cm sec–1 and 0.11 cm for the posterior cerebral artery (PCA), 19.5 cm sec–1 and 0.07 cm for the superior cerebellar artery (SCA), 19.6 cm sec–1 and 0.04 cm for the anterior inferior cerebellar artery (AICA), 14.9 cm sec–1 and 0.05 cm for the posterior inferior cerebellar artery (PICA), 28.3 cm sec–1 and 0.18 cm for the basilar artery, and 18.5 cm sec–1 and 0.16 cm for the vertebral artery, respectively. Since the flow velocities of these arteries were confined in a narrow range compared to the cross-sectional areas, the latter was considered to be the primary determinant for flow volume in these arteries. Based on certain assumptions, we estimated the flow volume of the PCA, SCA, AICA and ICA to be 60, 20, 10 and 10 ml min–1, respectively, which could be regarded as the current reference values for the arterial flow volumes. [Neurol Res 2000; 22: 194-196]

くも膜下出血で発症した解離性椎骨動脈瘤の手術

くも膜下出血で発症した解離性椎骨動脈瘤の手術