Diagnosis of middle cerebral artery occlusion with transcranial color-coded real-time sonography.

PURPOSETo determine the usefulness of transcranial color-coded real-time sonography in detecting occlusion of the horizontal portion of the middle cerebral artery.METHODSUsing transcranial color-coded real-time sonography, we measured the end-diastolic flow velocity with incident angle correction and the side-to-side ratio of the end-diastolic flow velocity (the end-diastolic ratio) in both middle cerebral arteries in 44 patients with or without occlusive disease. Cerebral angiography was carried out in all patients before or within 1 week after sonography. The subjects included 4 patients with unilateral stenosis of the extracranial internal carotid artery > or = 75%; ICS group), 6 with unilateral occlusion of the extracranial internal carotid (ICO group), 6 with occlusion of the horizontal portion of the middle cerebral artery (M1 group), and 28 without stenotic (< 75%) lesions in the internal carotid artery (control group).RESULTSIn the control group, the end-diastolic flow velocity was 40.4 +/- 16.8 cm/s (mean +/- SD) and the end-diastolic ratio was 1.28 +/- 0.27. In the ICS and ICO groups, the end-diastolic flow velocities on the affected side and the end-diastolic ratios were 33.4 +/- 9.0 cm/s and 1.35 +/- 0.24, and 29.6 +/- 10.2 cm/s and 1.67 +/- 0.58, respectively. In the M1 group, the end-diastolic flow velocity (16.7 +/- 4.29 cm/s) on the occluded side was significantly lower than that in the other groups. The end-diastolic ratio (3.53 +/- 1.47) in the M1 group was significantly higher than that in the other groups.CONCLUSIONThe M1 group could be easily distinguished from the other groups on the basis of the end-diastolic ratio. Measurement of the end-diastolic flow velocity and the end-diastolic ratios in the middle cerebral artery by means of transcranial color-coded real-time sonography may help to identify an occlusion in the horizontal portion of the middle cerebral artery.     

Diagnosis of middle cerebral artery occlusive lesions with contrast-enhanced transcranial color-coded real-time sonography in acute stroke

It is useful to evaluate the occlusive lesions of middle cerebral artery (MCA) occlusion with transcranial color-coded real-time sonography (TCCS). However, TCCS criteria for locating the site of the MCA occlusion has, as yet, remained unclear. The aim of the present study was to establish TCCS criteria for MCA occlusive lesions. We prospectively performed contrast-enhanced TCCS (CE-TCCS) in 75 consecutive acute stroke patients within 24 h of digital subtraction angiography. Patients were divided into four groups: occlusion of the MCA stem (MO group, n=12); occlusion of the MCA branch (MBO group, n=10); stenosis of the MCA stem (MS group, n=9); and no occlusive or stenotic lesions (control group, n=44). The following parameters were measured: peak systolic velocity (PSV) and end diastolic velocity (EDV) of bilateral MCA stems, and ED-ratio (the side-to-side ratio of the EDV). We establish the CE-TCCS criteria for MCA occlusive lesions using the sensitivity–specificity curve analysis. A PSV of 170 cm/s distinguished MCA stenosis from other groups (positive and negative predictive values and the accuracies were 100%, 99.0% and 99.1%, respectively). An EDV of 26 cm/s differentiated MO or MBO from the other groups (positive and negative predictive values and the accuracies were 84.6%, 100% and 96.5%, respectively). An ED-ratio of 2.5 discriminated MO from the MBO group (positive and negative predictive values and the accuracies were 88.9%, 85.7% and 87.5%, respectively). Measurement of MCA stem flow velocity with CE-TCCS can identify MCA stem stenosis and occlusion, as well as MCA branch occlusion.     

Doppler sonography in basilar artery occlusion

Summary We have investigated 6,972 patients with directional continuous-wave Doppler sonography within the last three and a half years, and have derived criteria for the sonographic diagnosis of basilar artery occlusion or tight stenosis in conjunction with 1,071 retrograde brachial angiograms. By sonographic patterns, we have suspected obstruction of the basilar artery or of both distal vertebral arteries in nine cases. Either bilateral sonographic silence or the absence of a diastolic flow component of the vertebral arteries served as criteria in the sonographic evaluation. Angiography of the vertebro-basilar system, performed in eight cases, showed near or complete occlusion in the distal vertebrals or in the proximal basilar artery. Degrees of stenosis less than an 80 percent reduction in lumen diameter could not be detected sonographically. Two further basilar artery occlusions were detected by means of angiography despite negative Doppler sonography: one of these patients showed an extensive collateral circulation between the posterior inferior and the superior cerebellar arteries, and one patient had an occlusion only of the middle and rostral thirds of the basilar artery, the proximal third and the anterior inferior cerebellar arteries being widely patent. Thus, we believe that directional CW Doppler sonography is very useful in the diagnosis of near or complete occlusion of both distal vertebral arteries or of the proximal basilar artery.     

Carotid artery: elliptic centric contrast-enhanced MR angiography compared with conventional angiography

PURPOSE: To determine the accuracy of elliptic centric contrast material-enhanced magnetic resonance (MR) angiography by using conventional angiography as the reference standard. MATERIALS AND METHODS: Fifty patients were examined prospectively with contrast-enhanced MR angiography and conventional angiography. The two examinations were performed within 1 week of each other. Two patients underwent conventional angiography of only one carotid artery, which yielded 98 arteries for comparison. RESULTS: With conventional angiography as the reference standard and by using a 70% threshold for internal carotid arterial diameter stenosis, maximum intensity projection (MIP) images had a sensitivity of 93.3%, specificity of 85.1%, and accuracy of 87.6%, whereas reformatted transverse source images had a sensitivity of 83.3%, specificity of 97.0%, and accuracy of 92.8%. Interobserver variability for conventional angiograms was 0.97, for MIP images was 0.91, and for source images was 0.90. The contrast-enhanced MR angiographic technique had a sensitivity of 88.9% and specificity of 58.1% for the presence of irregularity and/or ulceration. All 50 examinations were triggered appropriately so that minimal or no venous signal intensity was depicted. CONCLUSION: Contrast-enhanced elliptic centric three-dimensional MR angiography offers high-spatial-resolution, venous-suppressed images of the carotid arteries that appear to be adequate to replace conventional angiography in most patients examined prior to carotid endarterectomy.     

Detection and monitoring of cerebral hemodynamic disturbances with transcranial color-coded duplex sonography in patients after head injury

Reduced cerebral blood flow after severe head injury results in an increased risk of ischemic brain damage. Blood flow should therefore be monitored with a simple, reliable method. Transcranial color-coded Doppler sonography (TCCS) is an accepted tool for the diagnosis of cerebral vasospasm; however, its usefulness in evaluating patients with head injury has not been proven. Cerebral blood-flow velocity in the middle, anterior, and posterior cerebral arteries was measured with a 2.5 MHz probe (Aplio SSA 770A, Toshiba, Japan) in 36 subjects with moderate or severe head injury. Serial measurements of resistance index (RI), peak-systolic, end-diastolic, and mean velocity in the middle cerebral arteries were performed 2–24 h after head trauma and in the subsequent days during hospitalization. Immediately after head trauma, increased RI values, and unusually decreased blood-flow velocity (mainly in MCA) were observed. Microcirculation disturbances were suspected because the end-diastolic velocity had substantially diminished. Changes in blood-flow parameters correlated with the clinical state, and in most cases, a poor prognosis. In some patients, blood-flow velocity increased above the normal reference limit and this implied poor prognosis. Transcranial color-coded Doppler sonography is a reliable, repeatable, and accessible tool that provides information about cerebral blood-flow disturbances and may hold diagnostic and prognostic importance.     

Correlation of contrast-enhanced power Doppler sonography and conventional angiography of abduction-induced hip ischemia in piglets

OBJECTIVE: The purpose of this study was to determine if enhanced power Doppler sonography can detect early ischemia of the capital femoral epiphysis induced by hip hyperabduction in piglets and to correlate these findings with angiography. MATERIALS AND METHODS: Proximal femoral perfusion was evaluated in 18 studies of 10 piglet hips with unenhanced power Doppler sonography, enhanced power Doppler sonography with IV contrast agent, and digital angiography, in neutral position, hyperabduction, and after release to neutral position. Enhancement ratios between pixel intensities of power Doppler sonography and enhanced power Doppler images in each position were calculated. Angiograms were analyzed for differences in flow with changes in hip position. RESULTS: With the piglet in neutral position, power Doppler sonography revealed few vessels in the femoral head. Contrast administration resulted in a temporary marked increase in the visualization of vessels in the femoral head. Quantitative enhanced power Doppler sonography revealed a marked decrease in pixel intensity with abduction (p < 0.001) that was not apparent on unenhanced studies (p = 0.28). The enhancement ratio decreased from 0.45 (mean +/- SD, +/- 0.26) in neutral position to 0.10 (+/- 0.21) after abduction; it returned to 0.41 (+/- 0.14) after release of abduction (p < 0.001 for each comparison). Angiographic studies in hyperabduction revealed a variable level of ischemia. CONCLUSION: Enhanced power Doppler sonography can be used to visualize the vascular supply to the cartilaginous femoral head in piglets and can detect reversible ischemia induced by hip hyperabduction. These differences correlate with digital angiographic evidence of ischemia.     

Preoperative evaluation of carotid artery stenosis: comparison of contrast-enhanced MR angiography and duplex sonography with digital subtraction angiography

BACKGROUND AND PURPOSE: Contrast-enhanced MR angiography and extracranial color-coded duplex sonography are noninvasive, preoperative imaging modalities for evaluation of carotid artery stenosis. Innovative techniques and improvements in image quality require frequent reassessment of accuracy, reliability, and diagnostic value compared with those of digital subtraction angiography (DSA). We evaluated contrast-enhanced MR angiography and duplex sonography compared with DSA for detection of high-grade carotid artery stenoses. METHODS: Four readers, blinded to clinical symptoms and the outcome of other studies, independently evaluated stenoses on contrast-enhanced MR angiograms in 71 vessels of 39 symptomatic patients. Duplex sonography was also performed in all vessels. The severity of stenosis was defined according to North American Symptomatic Carotid Endarterectomy Trial criteria (0-29%, 30-69%, 70-99%, 100%). Results of both modalities were compared with the corresponding DSA findings. RESULTS: Contrast-enhanced MR angiography had a sensitivity and specificity of 94.9% and 79.1%, respectively, for the identification of carotid artery stenoses of 70% or greater. Sensitivity and specificity of duplex sonography were 92.9% and 81.9%, respectively. Combining data from both tests revealed a sensitivity and specificity of 100% and 81.4%, respectively, for concordant results (80% of vessels). CONCLUSION: Concordant results of contrast-enhanced MR angiography and duplex sonography increase the diagnostic sensitivity to 100%. The reliability of MR angiography is comparable to that of DSA. The combination of contrast-enhanced MR angiography and duplex sonography might be preferable over DSA for preoperative evaluation in most patients, thus reducing the risk of perioperative morbidity and improving the overall outcome.     

Assessment of the collateral function of the circle of Willis: three-dimensional time-of-flight MR angiography compared with transcranial color-coded duplex sonography

BACKGROUND AND PURPOSE: Identification of the intracranial collaterals assists in identifying patients with severe occlusive disease of the internal carotid arteries who are at lower risk of transient ischemic attacks (TIAs) and stroke. We investigated the usefulness of MR angiography in identifying functional collaterals of the circle of Willis. METHODS: MR angiography of the circle of Willis was performed in 50 healthy volunteers. Visibility was used as the criterion to define the intracranial collaterals as being functional. Two observers independently assessed the MR angiograms. Results were compared with those of transcranial color duplex sonography (TCCD), and results of carotid compression tests were the standard of reference for the identification of functional intracranial collaterals. RESULTS: With MR angiograms, reviewer 1 achieved a sensitivity of 85%, a specificity of 81%, a positive predictive value of 95%, and a negative predictive value of 55%. Reviewer 2 achieved a sensitivity of 87%, a specificity of 67%, a positive predictive value of 92%, and a negative predictive value of 53%. Interobserver agreement on MR angiograms was moderate (kappa = 0.57, 95% confidence interval: 0.42, 0.72). CONCLUSION: Visible collaterals of the circle of Willis on MR angiograms are able to supply collateral flow in the presence of carotid artery obstruction. However, the low negative predictive value of MR angiography indicates that, if collaterals are not visible, supplementary TCCD investigation is required.     

Evaluation of carotid artery stenosis: contrast-enhanced magnetic resonance angiography compared with conventional digital subtraction angiography.

OBJECTIVE: To compare retrospectively high-resolution contrast-enhanced magnetic resonance angiography with centric k-space filling and digital subtraction angiography in the assessment of degree of carotid artery stenosis. METHODS: Two neuroradiologists independently evaluated 14 carotid arteries (in 7 patients), and the degree of carotid stenosis determined was compared to calculate interobserver reliability. Thirty-six carotid arteries (in 18 patients) were then assessed with both contrast-enhanced magnetic resonance angiography and digital subtraction angiography. The degree of stenosis was determined by consensus, and the findings of the 2 modalities were compared. RESULTS: Close interobserver agreement was found with an intraclass correlation coefficient of 0.98 (95% confidence interval 0.95-0.99). Sensitivity of 86% and specificity of 91% were found for contrast-enhanced magnetic resonance angiography detection of surgically significant carotid stenosis compared with digital subtraction angiography. The Spearman rank correlation test also found a significant correlation (R(s) = 0.90, p < 0.001) in the comparison of the classifications of degree of carotid artery stenosis. CONCLUSION: Contrast-enhanced magnetic resonance angiography shows excellent correlation with digital subtraction angiography for the evaluation of carotid artery disease and has the potential to replace it in the assessment of degree of carotid artery stenosis.     

Transcranial color-coded real-time sonographic criteria for occlusion of the middle cerebral artery in acute ischemic stroke

BACKGROUND AND PURPOSE: Transcranial color-coded real-time sonography (TCCS) is a useful tool to evaluate disease of the middle cerebral artery (MCA). This study was undertaken to identify TCCS criteria for the diagnosis of MCA stem and MCA branch occlusions. METHODS: TCCS and digital subtraction angiography were performed in 55 consecutive patients with acute stroke: 10 with MCA stem occlusion, the MO group; eight with MCA branch occlusion, the MB group; and 37 with nonocclusive lesions, the control group. We measured the end-diastolic velocity (EDV) of the bilateral MCA stems and calculated the end-diastolic ratio by dividing the EDV of the unaffected side by that of the affected side. RESULTS: EDV was highest in the control group, and end-diastolic ratio was highest in the MO group. An EDV of >25 cm/s indicated a nonocclusive lesion in the MCA, with a positive predictive value of 98.4%, a negative predictive value of 81.0%, and an accuracy of 93.9%. An EDV of or=2.7 indicated MCA stem occlusion with a positive predictive value of 100%, a negative predictive value of 100%, and an accuracy of 100%. CONCLUSION: We developed TCCS criteria for the diagnosis of MCA diseases. MCA flow velocity detected by means of TCCS can help identify MCA stem occlusion as well as MCA branch occlusion.     

冠状动脉造影正常患者64排CT冠状动脉成像结果分析

目的 分析介入性冠状动脉造影正常患者64排CT冠状动脉成像的检查结果和影像特点.方法 对介入性冠状动脉造影结果为阴性的52例患者在1月内行64排CT冠状动脉成像检查,对阳性病例进行回顾性分析.结果 64排CT冠脉成像显示52例中,冠状动脉局限性管壁增厚29例(55.77%),管腔无狭窄23处,轻度狭窄6处,平均狭窄程度8%;弥漫性管壁增厚8例(15.38%),管腔无狭窄1例,轻度狭窄7例,平均狭窄程度为11%;单纯内膜钙化或管壁内钙化3例(5.77%),管腔未见明显狭窄.结论 64排CT冠状动脉成像更适宜作为冠心病诊断的首选影像检查方法.     

Carotid artery stenting and follow-up: value of 64-MSCT angiography as complementary imaging method to color-coded duplex sonography

Purpose

To compare 64-multi-slice-CT angiography (64-MSCTA) to color-coded duplex sonography (CCDS) in the follow-up after carotid artery stenting (CAS).

Methods

Thirty patients who had an MSCTA and CCDS examination prior and after CAS were included. Twelve closed-cell and 24 open-cell stents were implanted. Neointimal surface, in-stent-restenosis (ISR), stent expansion, and fracture were evaluated. In addition, the occurrence of atherosclerotic lesions leading to a > 50% stenosis in supraaortic vessels was assessed.

Results

With MSCTA, >50% ISR was found in 5.6% of cases during a mean follow-up of 41.7 months. Comparing MSCTA and CCDS, grading of ISR and absolute diameters of neointimal surface correlated moderately (Spearman = 0.402, p = 0.015; Pearson = 0.404, p = 0.03). Assessment of the neointimal surface was significantly better with MSCTA (100% vs. 80.6%; p = 0.011). Stent expansion was significant, compared to the basic value, with both modalities and stent types (p < 0.001). Of 237 additionally assessed vessel segments, a > 50% stenosis was detected in 38 (16.0%) vessel segments. Findings were stable in 25 (10.5%) and progressed in 11 (4.6%) vessel segments. Five small intracranial aneurysms were detected in four (13.3%) patients. Of 21 incidental findings in 16 (51.6%) patients there was one with malignancy (4.8%).

Conclusion

With regard to ISR and stent expansion, no significant difference was found, when MSCTA and CCDS were compared. CTA is quite applicable as a complementary imaging method for the follow-up of patients with carotid artery stents. Additional advantages are the detection of supraaortic vessel pathologies and incidental findings.     

Contrast-enhanced transcranial color-coded duplexsonography in stroke patients with limited bone windows

BACKGROUND AND PURPOSE: Thickening of the temporal bone in stroke-age patients may obviate sonographic evaluation of the circle of Willis in 20% to 30% of patients. We assessed the diagnostic efficacy of contrast-enhanced transcranial color-coded duplexsonography (TCCD) for noninvasive evaluation of the circle of Willis in stroke patients with limited bone windows. METHODS: Of 171 consecutive patients who presented with ischemic symptoms in the middle cerebral artery (MCA) territory, 49 patients (32 female, 17 male; age range, 70.5+/-10.6 years) had no detectable colorflow signals from the circle of Willis by TCCD because of limited acoustic windows. These 49 patients received an IV injection of a sonographic contrast-enhancing agent, Levovist (Schering; Berlin, Germany), and were re-examined. Correlative imaging studies of the circle of Willis were obtained in 42 of 49 of these patients. RESULTS: In 38 of 49 patients, contrast-enhanced TCCD enabled full visualization of the circle of Willis bilaterally; in an additional five patients, contrast-enhanced TCCD revealed only the portion of the circle of Willis ipsilateral to the probe through one temporal bone. In six of these 43 patients, contrast-enhanced TCCD showed MCA stenosis and MCA occlusion in three; three of the six cases of MCA stenosis and all three cases of the MCA occlusion were found on the symptomatic side. In six of 49 patients, no colorflow signals were obtained after contrast enhancement. All contrast-enhanced TCCD findings were confirmed by CT angiography, transfemoral digital subtraction angiography, MR angiography, or a combination of all three correlative studies. Levovist produced no serious adverse events. CONCLUSION: In stroke-age patients with limited acoustic windows, contrast-enhancement with Levovist can markedly increase the sensitivity of TCCD and increase the detection of clinically relevant intracranial arterial disease.     

Transcranial doppler sonography and CT angiography in patients with atherothrombotic middle cerebral artery stroke

BACKGROUND AND PURPOSE: Atherothrombotic disease of the middle cerebral artery (MCA) frequently occurs in Asian populations. This abnormality can be noninvasively assessed with transcranial Doppler sonography (TCD) and computed tomographic angiography (CTA). To our knowledge, the usefulness of TCD sonography compared with CTA in the diagnosis of nonembolic MCA disease has not been studied. METHODS: We prospectively examined 70 patients with clinically suspected atherothrom botic MCA stroke by using TCD sonography and CTA. We excluded patients with a known source of cardiac emboli, significant carotid stenosis, or classic lacunar syndrome. TCD sonography was performed within 2 days of admission, followed by CTA within 7 days after stroke onset. RESULTS: CTA demonstrated MCA stenosis of more than 50% in 57 patients (81%), whereas only 29 patients (41%) had abnormal TCD findings. CTA showed proximal M1 stenosis, distal M1 stenosis, and M2 disease in 29%, 29%, and 24% of the patients, respectively. Stenotic sites differed between patients with normal TCD results and those with abnormal results. TCD findings correlated well with CTA findings in all patients with proximal M1 stenosis. In contrast, TCD sonography correctly depicted distal M1 or M2 disease in only 24% of the patients. CONCLUSION: In this population, CTA is superior to TCD sonography in the diagnosis of MCA disease. Abnormal TCD results are highly suggestive of MCA stenosis. However, normal TCD findings do not exclude such lesions, especially in patients with distal M1 or M2 disease. Because distal M1 and M2 disease was found in half of our patients, TCD sonography should not be used as a method to screen for MCA stenosis.     

Partial fat-saturated contrast-enhanced three-dimensional MR angiography compared with non-fat-saturated and conventional fat-saturated MR angiography

Abdominal three-dimensional magnetic resonance angiography was performed in 35 patients in the equilibrium phase without fat saturation, with conventional fat saturation, and with fast partial fat saturation. Qualitative and quantitative evaluation demonstrated significantly better vessel visualization with both fat-saturated techniques. The partial fat-saturated technique provided water-specific images within a breath hold, reducing motion artifacts significantly.     

Echo-enhanced transcranial color-coded duplex sonography in the diagnosis of cerebrovascular events: a validation study

BACKGROUND AND PURPOSE: Transcranial color-coded duplex sonography (TCCD) is a diagnostic technique for evaluation of intracranial arteries in patients with acute stroke. Echo-enhancing contrast agents (EEAs) are necessary to visualize intracranial vessels in up to 30% of patients because of limited acoustic bone windows. In this study, we assessed the diagnostic efficacy of echo-enhanced TCCD (eTCCD) in correlation with the gold standard, digital subtraction angiography (DSA). METHODS: We prospectively evaluated all patients with eTCCD who subsequently underwent DSA for evaluation of cerebrovascular symptoms over a 24-month period. We administered Levovist as an EEA. Two blinded reviewers analyzed all eTCCD findings and correlated them with DSA. RESULTS: We included 132 consecutive patients (40 women, 92 men; mean age, 58 +/- 14 years) with 164 datasets: 24/164 had normal findings, 98/164 had abnormalities of extracranial carotid arteries, 32/164 had abnormalities of intracranial arteries, and 21/164 had abnormalities in vertebrobasilar circulation as determined by DSA. For eTCCD, we found a sensitivity of 82% (95% confidence interval [CI]: 75%-90%), a specificity of 98% (95% CI: 90%-100%), a positive predictive value of 99% (95% CI: 94%-100%), and a negative predictive value of 75% (95% CI: 64%-85%); 7/164 (4%) examinations were inconclusive because of insufficient bone windows. The interobserver agreement was almost perfect (kappa value, 0.92; 95% CI: 0.87-0.97). CONCLUSION: eTCCD provides high diagnostic validity for the status of the major intracranial arteries. In particular, a normal vessel status reliably assessed by an experienced sonographer could supersede further imaging procedures. In patients with acute ischemic stroke not eligible for established angiographic techniques, eTCCD may be useful as an alternative imaging technique.     

应用DSA诊断椎-基底动脉变异

目的探讨椎基底动脉变异的种类和发生率及DSA影像学特征,提高对椎基底动脉变异临床意义的认识。方法对6432例患者均进行全脑血管进行造影,对全脑血管造影的DSA图像资料进行回顾性分析,得出椎基底动脉变异的发生率及变异血管合并其他血管病变的情况。结果发生椎动脉起源变异272例患者278支椎动脉,检出率为4.3%,其中左椎动脉起源异常270支(4.2%),右椎动脉起源异常8支;左椎动脉起源异常中,258支直接起自主动脉弓,2例为双起源椎动脉,4支起自颈内动脉,6支起自左锁骨下动脉根部。8支右椎动脉起源异常中,2支直接起源于右颈总动脉,2支起自右颈内动脉动脉,2例为双起源椎动脉,2支直接起自头臂干动脉。141例椎基底动脉成窗(2.19%);61支小脑后下动脉起自颅外段位置较低部位。11例永久性原始三叉动脉。另外,有9例变异结构的远端或近端伴发动脉瘤、2例伴发动静脉畸形。7例出现与成窗结构供血区相一致的一过性脑缺血症状,其中2例出现经成窗结构远端供血部位的脑梗塞,1例出现经双起源椎动脉供血部位的脑梗塞。结论脑血管DSA可以清晰显示椎基底动脉变异的位置、形态、毗邻关系及有无伴发其他血管性病变;掌握椎基底动脉变异的DSA影像学表现及血流动力学特征,对脑血管病的明确诊断及手术和介入治疗方案的制定具有重要临床意义。     

Acute basilar artery occlusion (BAO): a pictorial review of multimodal imaging findings

Emergency Radiology - Acute basilar artery occlusion (BAO) is an uncommon cause of stroke; however, it constitutes a serious medical emergency and is associated with elevated mortality rates as...