Distal Branches Of Middle Cerebral Artery Research Articles

Competitive leptomeningeal flow impact on thrombectomy reperfusion grade rating

BackgroundCompetitive leptomeningeal flow (CLF) can be observed immediately after mechanical thrombectomy (MT) reperfusion with retrograde contrast clearing of the distal leptomeningeal branches from non-contrast opacified flow through different vascular territories....

Abstract WP141: Leptomeningeal Competitive Flow Impact on Thrombectomy Reperfusion Grade Rating

Background: The extent of reperfusion following thrombectomy (MT) for large vessel occlusion strokes is predictive of outcomes. There is still inter-rater variability in the reperfusion scoring. We noticed that some patients present with retrograde contrast clearing of the distal branches from non-contrast-opacified flow originated from different territories. We aim to evaluate the frequency of this phenomenon (“competitive flow” (CF)), to evaluate if it has an association with the degree of leptomeningeal collaterals, and its impact on eTICI score. Methods: This is a retrospective-analysis of our MT database spanning 11/2020-12/2021. We included consecutive cases of intracranial internal carotid (i-ICA) and middle cerebral artery (MCA) M1 occlusions. CF was defined by the observation of retrograde clearing of distal MCA branches that were previously opacified by antegrade reperfusion. The clearance of the distal branches is presumed to occur due to CF via non-contrast-opacified PCA or ACA flow. The washout was considered CF if it cleared abruptly with or without forward reconstitution of antegrade opacification. Results: We included a 125 patients. Median age was 64years, 51%were males. Baseline median NIHSS was 17 and ASPECTS 9. Median last-known-well-time to puncture was 7 hours, 30.4% received tPA. Final eTICI2c-3 was achieved in 81.6%. CF was present in 32(25.6%)patients. Baseline characteristics were similar between both groups. The CF arm had better leptomeningeal single-phase-CTA-collaterals(p=0.01) and smaller CTP malignant hypoperfusion volume(p=0.06) VS non-CF. The inter-rater-agreement for eTICI score was moderate when CF was present and excellent in its absence (Krippendorf’s alpha=0.65 and 0.81,respectively). There was poor agreement (K-value=0.3) for the presence versus absence of CF between both operators. Reviewer 1 (2-year-post-training) had correctly identified 46% of patients with consensus CF vs 90% to Reviewer 2 (9-year-post-training) after the consensus read. Conclusion: CF was observed in 32% of patients. CF was found to be associated with better collateral flow, and to impact the reported procedural eTICI rating.

Asymptomatic diffuse cerebritis presenting as middle cerebral artery infarct

Diffuse cerebritis is a devastating disease presenting with features of raised intracranial tension, deficits, and features of meningeal and neural irritation. The most common feature is seizures which may persist despite normal antiepileptic medication. We present a patient with diffuse cerebritis who presented as a subacute middle cerebral artery (MCA) territory infarct without any symptoms of meningeal irritation or infection. The patient once admitted deteriorated with pupillary asymmetry and loss of consciousness. A computerized tomography scan revealed a massive increase in cerebral edema of the infarcted brain with midline shift and mass effect. In view of the serious threat to life, a decompressive craniectomy was done. Once the dura was opened, pus was seen subpially oozing into the subdural space. This was sampled for analysis and the scalp flap was closed with a drain. The patient improved well post surgically and was gradually extubated. His pus was found to grow Klebsiella pneumoniae sensitive to amikacin and gentamicin. A prolonged course of antibiotics was started. An angiogram done to determine the cause of the infarct showed only distal MCA branches (M4) occluded. The patient later deteriorated with venous thrombosis and succumbed to his illness later. We present a discussion on the etiology of the patient's condition and possible treatment options when faced with such situations.

Assessment of collateral blood flow in patients with distal branch occlusion of the middle cerebral artery

Aim of this study was to evaluate the collateral blood flow between more distal branches of the middle cerebral artery (MCA) in the case of peripheral MCA branch occlusion on dynamic 4D angiograms. We sought to individually predict the finally resulting infarction volume with regard to the extent of collateral blood flow. Overall, 35 acute ischemic stroke patients with peripheral MCA branch occlusion were included. Volumes of the ischemic infarctions and perfusion deficits were measured on diffusion-weighted images DWI and time-to-peak TTP (> 4 s). Collateral flow on 4D MR angiograms were classified as previously specified. On DWI, the ischemic lesions had a mean volume of 3.4 ± 15.1 mL while the mean volume on TTP (> 4 s) was significantly larger 22.0 ± 18.1 mL (P < 0.001). On dynamic 4D angiograms we observed grade 1 in 8 (22.9%), grade 2 in 4 (11.4%), grade 3 in 10 (28.6%), and grade 4 in 13 (37.1%) patients. In comparison to patients with better collateralization (grade 3-4) patients with less sufficient collateralization (grade 0-2) demonstrated larger infarction volumes on initial (11.1 mL (IQR 2.9-35.5) vs. 2.1 mL (IQR 0.5-4.5), P = 0.03) and follow-up DWI (15.5 mL (IQR 12.6-23.3) vs. 1.9 mL (IQR 0.5-4.5), P = 0.03) with prominent infarction growth (7.4 mL (IQR 2.6-10.1) vs. 0.9 mL (IQR 0.2-2.6), P = 0.08). In the majority of cases with distal MCA branch occlusion a good collateral blood flow has been observed. Nevertheless, in approximately one quarter of patients an insufficient collateral blood flow has been detected that was associated with substantial infarction growth.

Distal Middle Cerebral Artery Branch Recanalization Does Not Affect Final Lesion Volume in Ischemic Stroke

Background: Early recanalization in ischemic stroke is associated with favorable outcome. However, limited data are available on the effect of recanalization on infarct growth and functional outcome in stroke with distal middle cerebral artery (MCA) pathology. This study was aimed at determining the effect of recanalization in acute stroke patients with perfusion-diffusion mismatch and occlusion or high-grade stenosis of a distal MCA branch. Methods: We prospectively examined 34 consecutive stroke patients with perfusion-diffusion mismatch and M3 or M4 pathology within 24 h of symptom onset. The MRI protocol consisted of diffusion-weighted images (DWI), fluid-attenuated inversion recovery (FLAIR), T2*, perfusion-weighted imaging, time-of-flight magnetic resonance angiography at days 0, 1, and 4-6. Volume measurements were performed with MRIcron. Infarct growth was defined as the difference between lesion volumes on FLAIR at days 4-6 and DWI at day 0. Certified raters assessed modified Rankin Scale scores at discharge and day 90. Results: Twenty-four patients (71%) showed recanalization at day 1. Infarct growth was modest (median 2.4 mL, 95% CI 0.8-6.7) and not significantly different between patients with and without recanalization (p = 0.87). Functional outcome at discharge was good with 70% of patients suffering no significant disabilities. There was no association between functional outcome at discharge and recanalization (OR 2.1, 95% CI 0.4-13.0, p = 0.40) or infarct volume at days 4-6 (p = 0.40). Conclusions: The high rate of spontaneous recanalization and good functional outcome in patients with distal MCA pathology might obscure a potential benefit from recanalization in this population.

Computed tomography angiography in the diagnosis of brain death: a systematic review and meta-analysis.

Physiological instability and confounding factors may interfere with the clinical diagnosis of brain death. Computed tomography angiography (CTA) has been suggested as a potential ancillary test for confirmation of brain death, but its diagnostic accuracy remains unclear. We searched MEDLINE, EMBASE, and CENTRAL for studies comparing CTA with other accepted methods of diagnosing brain death (clinical or radiographic). Summary estimates of diagnostic accuracy were computed using random effects models. Subgroup analyses and meta-regression were performed to assess associations between CTA sensitivity and study or patient characteristics. Twelve studies, involving 541 patients, were included. If the CTA criterion for brain death was complete lack of opacification of intracranial vessels, then the pooled sensitivity was 62% (50-74%) for venous phase and 84% (75-94%) for arterial phase imaging. The sensitivity of CTA was higher when the criterion for brain death involved absence of opacification of internal cerebral veins, either alone (99%, 97-100%) or in combination with lack of flow to the distal middle cerebral artery branches (85%, 77-93%). CTA sensitivity was not influenced by different reference standards (clinical vs. radiographic) or predominant diagnostic category (stroke vs. brain trauma). Specificity of CTA could not be adequately determined from the existing data. Many patients who progress to brain death by accepted clinical or radiographic criteria have persistent opacification of proximal intracranial vessels when CTA is performed. The specificity of CTA in the diagnosis of brain death has not been adequately assessed. Routine use of CTA as an ancillary test in the diagnosis of brain death is therefore not recommended until diagnostic criteria have undergone further refinement and prospective validation. Absence of opacification of the internal cerebral veins appears to be the most promising angiographic criterion.

Postoperative evaluation of superficial temporal artery‐middle cerebral artery bypass using an MR angiography technique with combined white‐blood and black‐blood sequences

To assess the performance of the hybrid of opposite-contrast MR angiography (HOP MRA) technique, which combines flow dephasing and compensating sequences, in the postoperative evaluation of superficial temporal artery (STA)-middle cerebral artery (MCA) bypass. Both 3D-HOP MRA and 3D-time-of-flight (TOF) MRA at 1.5 Tesla were performed in 19 patients after STA-MCA bypass. The two techniques were visually evaluated to compare the visualization of distal MCA branches and the length and number of depicted recipient MCA branches. Additionally, for the depicted recipient MCA branches, the contrast-to-noise ratio (CNR) and length were compared between the two techniques. The 3D-HOP MRA provided better visualization of the recipient MCA branches than 3D-TOF MRA in 10 of the 19 patients, while the depicted recipient MCA branches were longer on 3D-HOP MRA than on 3D-TOF MRA in 9 patients. Although not statistically significant, the average number of depicted recipient branches by 3D-HOP MRA (2.16) was greater than that by 3D-TOF MRA (1.79). 3D-HOP MRA was significantly superior to 3D-TOF MRA in both CNR (119.0 versus 74.3) and length of the recipient MCA branches (72.0 versus 49.9 pixels). 3D-HOP MRA is superior to 3D-TOF MRA for the detailed evaluation of STA-MCA bypass.

Isolated Hand Paralysis Due to Stroke in Precentral Knob Region (P02.191)

Objective: To document a rare presentation of stroke. Background Lhermitte described 9pseudoperipheral palsy9 as a weakness of fingers due to a CNS lesion, now thought to be 1% of all ischaemic strokes. Often misdiagnosed, the opportunities to identify and treat stroke risk factors are missed. Design/Methods: A 62 year-old male presented with difficulty of finger movements and wrist drop of left hand, for two days. Patient had history of hyperlipedemia. On exam, his blood pressure was 195/100mm Hg with normal vitals,left wrist drop, weak finger flexion,abduction and adduction, weak thumb extension flexion and adduction, with brisk left brachioradialis reflex. Rest of the neurological examination was normal. Results: Due to isolated hand weakness, we were tempted to think of peripheral lesion, however due to involvement of muscle supplied by radial, medial and ulner nerve and brisk brachioradialis reflex, MRI brain was done to look for central cause, which showed diffusion positive lesion in mid of the right precentral gyrus suggestive of acute stroke. Patient was managed for acute stroke and was discharged home with mild improvement of weakness. Conclusions: Functional MRI suggests that the w or E shaped area (the precentral knob) on the precentral gyrus in the axial plane is the hand area. Medial portion of the precentral knob representing topographically ulnar-sided fingers may correspond to the borderzone area between the middle cerebral artery (MCA) and the anterior cerebral artery, whereas the lateral portion representing radial-sided fingers is supplied by distal MCA branches. Cortical hand paralysis characteristically cause partial finger paralysis, producing pseudo-ulner or pseudoradicular pattern with difference in the severity of paralysis between the radial side and the ulnar side, important in differentiating cortical hand paralysis from subcortical lesions. Discrete functional cortical areas for each digit exist and are sequentially arranged, with considerable overlap of control of adjacent territory. Disclosure: Dr. Vyas has nothing to disclose. Dr. Staudinger has nothing to disclose. Dr. Hanson has nothing to disclose.

Spontaneous Resolution in Dissecting Aneurysms of the Distal Middle Cerebral Artery

Spontaneous resolution of intracranial aneurysms is a rare phenomenon. We describe two cases of ruptured distal middle cerebral artery branch aneurysms associated with initial neurological deficit. Follow-up angiography showed complete resolution of the aneurysms.

Clinical implications of collateral middle cerebral artery flow in acute ischaemic stroke with internal carotid artery occlusion

The presence of collateral middle cerebral artery (MCA) flow via the primary collateral pathway is thought to protect against the progression of cerebral ischaemia. However, there have been few reports on early clinical outcomes according to the presence of collateral MCA flow in acute ischaemic stroke (AIS) with internal carotid artery (ICA) occlusion. Therefore, we sought to investigate the early clinical outcomes and lesion patterns according to the presence of collateral MCA flows in AIS with ICA occlusion. This is a retrospective study of patients with AIS with ICA occlusion consecutively admitted to our stroke center between October 2008 and March 2010. Patients were included if they were admitted within 12 h of symptom onset with AIS and symptomatic ICA occlusion. Collateral MCA flow was defined as the presence of MCA signals from proximal M1 to distal MCA branches ipsilateral to the ICA occlusion by magnetic resonance angiography. Early neurological deterioration (END) was defined as a 4-point increase in the National Institutes of Health Stroke Scale (NIHSS) score and persistent neurological deterioration for at least 24 h or newly developed neurological symptoms within 7 days. Sixty-five patients (42 men, 23 women) were finally included. Initial NIHSS scores were significantly lower, and favorable outcomes at 3 months were better in patients with collateral MCA flow than in those without (P < 0.001). Initial lesion patterns were different according to the collateral MCA flow. However, patients with mild AIS might more frequently deteriorate than those with moderate to severe AIS. In our study, collateral MCA flow reduced initial stroke severity and was associated with favorable outcomes at 3 months but did not seem to protect against END in mild AIS patients with ICA occlusion. Therefore, the results of this study suggest that mild AIS patients with ICA occlusion should be carefully managed because their conditions may deteriorate.

A Protocol for Characterizing the Impact of Collateral Flow after Distal Middle Cerebral Artery Occlusion

In humans and in animal models of stroke, collateral blood flow between territories of the major pial arteries has a profound impact on cortical infarct size. However, there is a gap in our understanding of the genetic determinants of collateral formation and flow, as well as the signaling pathways and neurovascular interactions regulating this flow. Previous studies have demonstrated that collateral flow between branches of the anterior cerebral artery (ACA) and the middle cerebral artery (MCA) can protect mouse cortex from infarction after middle cerebral artery occlusion. Because the number and diameter of collaterals varies among mouse strains and after transgenic manipulations, a combination of methods is required to control for these variations. Here, we report an inexpensive approach to characterizing the cerebrovascular anatomy, and in vivo monitoring of cerebral blood flow as well. Further, we introduce a new, minimally invasive method for the occlusion of distal MCA branches. These methods will permit a new generation of studies on the mechanisms regulating collateral remodeling and cortical blood flow after stroke.

Reliable Perfusion Maps in Stroke MRI Using Arterial Input Functions Derived From Distal Middle Cerebral Artery Branches

Perfusion imaging is widely used in stroke, but there are uncertainties with regard to the choice of arterial input function (AIF). Two important aspects of AIFs are signal-to-noise ratio and bolus-related signal drop, ideally close to 63%. We hypothesized that distal branches of the middle cerebral artery (MCA) provide higher quality of AIF compared with proximal branches. Over a period of 3 months, consecutive patients with suspected stroke were examined in a 3-T MRI scanner within 24 hours of symptom onset. AIFs were selected manually in M1, M2, and M3 branches of the MCA contralateral to the suspected ischemia. Signal-to-noise ratio and bolus-related signal drop were analyzed. Perfusion maps were created for every patient and mean values at the insular level as well as relative ranges were compared. Mean age of 132 included patients (53 females) was 67.3 years (SD, 14.9) and median National Institutes of Health Stroke Scale was 3 (interquartile range [IQR] 0 to 6). For further analyses, 4 patients were excluded due to discontinuation of scanning or insufficient bolus arrival (signal drop <15%). Median signal-to-noise ratio was highest in M3 branches (36.41; IQR, 29.29 to 43.58). Median signal-to-noise ratio in M2 branches was intermediate (27.54; IQR, 20.78 to 34.00) and median signal-to-noise ratio in M1 was low (12.40; IQR, 9.11 to 17.15). Using AIFs derived from M1 and M2 branches of the MCA median signal drop was 77% (IQR, 72% to 82%) and 78% (IQR, 73% to 83%), respectively. Signal drop was significantly reduced when AIF was selected in M3 branches with a median of 72% (IQR, 63% to 77%; P<0.01). Highest variability of 3456 perfusion maps was found in those derived from M1. The level of AIF selection in the MCA has a major impact on reliability and even quantitative parameters of perfusion maps. For better comparison of perfusion maps, the AIF should be defined by selection of distal branches of the MCA contralateral to the suspected ischemia. In future trials involving perfusion imaging, the MCA segment used for the AIF should be specified.

Recanalization of an Acute Middle Cerebral Artery Occlusion Using a Self-Expanding, Reconstrainable, Intracranial Microstent as a Temporary Endovascular Bypass

Although self-expanding intracranial microstents have been used to treat acute middle cerebral artery (MCA) stroke, there are disadvantages associated with placing a permanent endovascular implant. We describe a technique in which a reconstrainable stent was used to provide a temporary endovascular bypass to achieve MCA recanalization without permanent stent implantation. A 55-year-old male presented with acute onset left hemiplegia (National Institutes of Health Stroke Score (NIHSS) of 20. Angiography showed an occluded right cervical internal carotid artery (ICA), a patent anterior communicating artery (ACOMM), and embolic occlusion of the right middle cerebral artery (MCA), M1 segment. Working through a 6F guide-catheter positioned in the left cervical ICA, an SL-10 microcatheter, and 0.014-inch Synchro-2 microwire were manipulated across the anterior communicating artery and into the right M1 segment occlusion. 5 mg of abciximab and 3 mg tPA were infused directly into the thrombus through the microcatheter. Mechanical thrombolysis using the microwire and microcatheter was ineffective in achieving any recanalization. An Enterprise stent (4x22 mm) was delivered across the occlusion site and partially unconstrained. The unconstrained portion of the stent expanded and acted as a temporary bypass, to circumferentially displace and structurally disrupt the M1 thrombus, producing immediate revascularization of the right territory MCA. After approximately 20 minutes, the Enterprise stent was reconstrained and removed. Final angiography demonstrated excellent filling of the right M1 and distal MCA branches. The patient improved to an NIHSS of 7, regaining movement of his left upper and lower extremities. The temporary endovascular bypass technique yielded immediate and durable revascularization of an acutely occluded middle cerebral artery without the disadvantages associated with the placement of a permanent endovascular stent.

Infectious aneurysmal rupture presenting as massive intracerebral hemorrhage in a preterm baby

Infectious intracranial aneurysms in infantile period are very rare, and there is no report of infectious intracranial aneurysm in preterm infant A 43-day-old female infant, delivered at 29 weeks of gestation, presented with massive intracranial hemorrhage. Eighteen days after diagnoses of necrotizing enterocolitis, sepsis, and meningitis, the baby became lethargic with rigid left limbs. Imaging studies revealed a large hematoma in the right temporoparietal region and adjacent lateral ventricle. During removal of fresh hematoma, an actively bleeding nodular mass, contiguous with the distal middle cerebral artery branch, was found and excised from the parent vessel. Pathologic examination revealed a ruptured infectious intracranial aneurysm. After surgery, her neurologic status improved and she was doing well at 12 months' follow-up with mild spastic hemiparesis. To our knowledge, this is the first reported case of infectious intracranial aneurysm in the preterm infant, which was successfully treated with hematoma evacuation and resection of the aneurysm.

Orthogonal Interlocking Tandem Clipping Technique for the Reconstruction of Complex Middle Cerebral Artery Aneurysms

Complex aneurysms arising at the middle cerebral artery (MCA) bifurcation frequently present a microsurgical challenge to effectively obliterate while maintaining patency of the distal MCA branches. These aneurysms are often multilobed, with their long axis aligned with the long axis of the M1 trunk, placing the dome of the aneurysm in the surgeons' line of sight, preventing an unobstructed view of the entire bifurcation and proximal M1 segment. MCA aneurysms often have a broad neck, splaying the bifurcation. An orthogonal interlocking tandem clipping technique, maximizing the use of fenestrated aneurysm clips, is presented as a means to completely obliterate the aneurysm and simultaneously "reconstruct" the MCA bifurcation. CLINICAL PRESENTATIONS AND INTERVENTION: Fifteen complex MCA aneurysms were treated using an interlocking tandem clipping technique. In its simplest application, the blades of the initial aneurysm clip are incorporated into the fenestration of the second clip. Obliteration of the residual aneurysm is achieved with the blades of the second, fenestrated clip. Satisfactory aneurysm obliteration and reconstruction of the MCA bifurcation was achieved in all cases using this technique, with excellent neurological outcomes. Morphologically complex multilobed MCA aneurysms can be effectively clipped with "reconstruction" of the normal vascular anatomy using a tandem interlocking clipping technique. A fenestrated clip is used to incorporate the blades of the initial clip, while obliterating the remainder of the aneurysm.

The Hyperdense Posterior Cerebral Artery Sign

In the anterior circulation, the hyperdense middle cerebral artery (MCA) sign is a well-established marker for early ischemia. Similarly, the hyperdense basilar artery sign or the MCA "dot" sign may be a diagnostic clue for basilar artery or distal MCA branch thrombosis. The purpose of this study was to define the hyperdense posterior cerebral artery (PCA) sign and determine its incidence, diagnostic value, and reliability as a marker for ischemia in the territory of the PCA. Cranial computed tomographies (CCTs) of 48 patients with proven acute ischemia (<12 hours) in the PCA territory were compared by 3 independent and blinded readers to the CCTs of 86 age-matched patients without PCA infarction. Using follow-up imaging, the correlation of the hyperdense PCA (HPCA) with infarct size, thalamic infarction, and bleeding were investigated. An HPCA was found in 35.4% of all patients with PCA infarction, typically within the ambient cistern, with a specificity of 95.4%. The thalamus was affected significantly more often (P=0.009) and the size of the infarct was significantly more often large than medium (P=0.018) or small (P<0.001) when an HPCA was present. Hemorrhagic transformation tended to occur more often when the HPCA was present. An HPCA was detected in more than one third of all patients with PCA ischemia, suiting the incidence of the hyperdense MCA. Based on our results, this sign may not only be helpful in the early diagnosis of PCA infarction but might also act as a prognostic marker in acute PCA territory ischemic stroke.

Superficial Temporal Artery to Middle Cerebral Artery Bypass

The superficial temporal artery to middle artery bypass is a technique that allows the blood supply from the extracranial carotid circulation to be routed to the distal middle cerebral artery branches. The procedure allows blood flow to bypass proximal lesions of the intracranial vasculature. The performance of this bypass requires specialized microvascular training and the use of microvascular techniques. The techniques involved in performing these procedures include microdissection of the superficial temporal artery in the scalp, microdissection of the recipient middle cerebral artery branches near the sylvian fissure, and anastomosis techniques using either microvascular sutures or a microanastomotic device. The successful completion of the bypass and subsequent patency requires meticulous attention to technical details.

Awake Craniotomy for Microsurgical Obliteration of Mycotic Aneurysms: Technical Report of Three Cases

Infectious (mycotic) aneurysms that do not resolve with medical treatment require surgical obliteration, usually requiring sacrifice of the parent artery. In addition, patients with mycotic aneurysms frequently need subsequent cardiac valve repair, which often necessitates anticoagulation. Three cases of awake craniotomy for microsurgical clipping of mycotic aneurysms are presented. Awake minimally invasive craniotomy using frameless stereotactic guidance on the basis of computed tomographic angiography enables temporary occlusion of the parent artery with neurological assessment before obliteration of the aneurysm. A 56-year-old woman presented with progressively worsening mitral valve disease and a history of subacute bacterial endocarditis and subarachnoid hemorrhage 30 years previously. A cerebral angiogram revealed a 4-mm left middle cerebral artery (MCA) angular branch aneurysm, which required obliteration before mitral valve replacement. The second patient, a 64-year-old woman with a history of rheumatic fever, had an 8-mm right distal MCA aneurysm diagnosed in the setting of pulmonary abscess and worsening cardiac function as a result of mitral valve disease. The third patient, a 57-year-old man with a history of fevers, night sweats, and progressive mitral valve disease, had an enlarging left MCA angular branch aneurysm despite the administration of antibiotics. Because of their location on distal MCA branches, none of the aneurysms were amenable to preoperative test balloon occlusion. After undergoing stereotactic computed tomographic angiography with fiducial markers, the patients underwent a minimally invasive awake craniotomy with frameless stereotactic navigation. In all cases, the results of the neurological examination were unchanged during temporary parent artery occlusion and the aneurysms were successfully obliterated. Awake minimally invasive craniotomy for an infectious aneurysm located in eloquent brain enables awake testing before permanent clipping or vessel sacrifice. Combining frameless stereotactic navigation with computed tomographic angiography allowed us to perform the operation quickly through a small craniotomy with minimal exploration.

Vasospasm diagnosis: theoretical sensitivity of transcranial Doppler evaluated using 135 angiograms demonstrating vasospasm. Practical consequences.

The authors inspected 135 angiograms (A zero) demonstrating vasospasm (VS) after aneurysm (An) rupture. There were 54 anterior communicating artery (ACoA), 38 internal carotid artery (ICA) and 43 middle cerebral artery (MCA) ruptured aneurysms. VS was searched for on each A zero in distal branches of MCA (M2) proximal MCA (M1), ICA, anterior cerebral artery (A1) and pericallosal artery (A2). In each An group (ACoA - ICA - MCA) the theoretical sensitivity of transcranial doppler (TCD) was calculated postulating that when present (M1) or (M1 + ICA) or (M1 + ICA + A1) angiographic VS would be constantly and reliably recorded by TCD. If only M1 is insonated TCD sensitivity would be 54% after ACoA, 82% after ICA and 88% after MCA An rupture. If M1 and ICA are insonated TCD sensitivity would be 61% after ACoA, 95% after ICA and 88% after MCA An rupture. TCD sensitivity would be almost perfect with a reliable and constant A1 insonation but that hypothesis is today purely speculative. An additional A zero appears to be necessary to establish VS diagnosis, mainly after ACoA An rupture when a discrepancy is observed between normal TCD data and delayed clinical worsening.

The transsylvian approach to middle cerebral artery bifurcation/trifurcation aneurysms

A transsylvian approach to treat aneurysms located at the bifurcation/trifurcation of the middle cerebral artery (MCA) is described. This surgical route traces a distal MCA branch retrogradely into the Sylvian fissure whereupon a secondary MCA branch and the main stem of the MCA (M1) are identified before aneurysm clipping. The advantages, and disadvantages of this approach are discussed. The transsylvian route should be considered as an alternative to the traditional pterional approach, which utilizes proximal to distal dissection of the MCA, in situations when the M1 is long or when the pterional approach is inadvisable.