MRI and color-coded duplex sonography: diagnosis of partial priapism

A case of partial priapism is reported diagnosed by contrast-enhanced MR imaging and color-coded duplex sonography. Follow-up examinations after 4 weeks and 3 months were performed. According to the results of color-coded duplex sonography and MRI, a partial priapism with development from the subacute stage to a fibrous residuum after spontaneous lysis was diagnosed. There are only very few cases of partial priapism reported in the literature and this is the first case report that demonstrates diagnosis and follow-up both by color-coded duplex sonography and contrast-enhanced MR imaging.     

Transcranial color-coded duplex sonography in unilateral flow-restrictive extracranial carotid artery disease.

PURPOSETo provide transcranial color-coded duplex flow-velocity data for the basal cerebral arteries in patients with unilateral flow-restrictive extracranial carotid artery disease, and to compare these data with the flow velocities obtained in healthy control subjects.METHODSTranscranial color-coded duplex sonography was performed in 78 patients with different patterns of cross flow through the anterior and posterior communicating arteries associated with unilateral obstruction (70% to 100%; 46 stenoses and 32 occlusions) of the internal carotid arteries. Peak systolic, mean, and end diastolic velocities were measured in the anterior, middle, and precommunicating and postcommunicating posterior cerebral arteries. These measurements were compared with the values obtained in 125 age- and sex-matched health control subjects.RESULTSPatients with anterior communicating artery cross flow to the middle cerebral artery (63%) had increased peak velocity in the anterior cerebral artery and decrease peak velocity in the middle cerebral artery on the obstructed (ipsilateral) side, and increased peak velocity in the anterior cerebral artery on unobstructed (contralateral) side. Patients with anterior communicating artery cross flow to the pericallosal artery (19%) had increased contralateral peak systolic velocity and mean anterior cerebral artery velocities. Patients without anterior communicating artery cross flow (18%) had normal peak velocities in the anterior and middle cerebral arteries. Patients with posterior communicating artery cross flow (42%) had ipsilaterally decreased peak systolic and mean middle cerebral artery velocities and increased peak velocities in the precommunicating posterior cerebral artery. Patients without posterior communicating artery cross flow (58%) had ipsilaterally decreased peak systolic and mean middle cerebral artery velocities.CONCLUSIONOur findings suggest that typical abnormalities of basal cerebral artery flow velocities occur in patients with unilateral 70% to 100% obstruction of the internal carotid arteries resulting in different patterns of cross flow through the circle of Willis.     

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.     

Contrast-enhanced carotid color-coded duplex sonography for carotid stenting follow-up assessment

Proper assessment of endovascular patency after carotid stent (CS) placement with carotid color-coded duplex sonography (CCCD) can be difficult. We investigated the usefulness of contrast-enhanced (CE) CCCD for post-CS follow-up. CCCD images could not depict the entire bloodstream in overlapped stents and in highly positioned stents. CE-CCCD images, however, did provide anatomic information almost equivalent to that of intra-arterial angiography. CE-CCCD is useful in screening for post-CS restenosis.     

Transcranial color-coded duplex sonography for detection of distal internal carotid artery stenosis

BACKGROUND AND PURPOSE: Gradation of high-grade intracranial internal carotid artery (ICA) stenosis poses a challenge to noninvasive neurovascular imaging, which seems critical for angioplasty in the ICA segments C1 and C5. We investigated cutoff values of intracranial ICA stenosis for transcranial color-coded sonography (TCCS) and compared this method with the “gold standard,” digital subtraction angiography (DSA).Materials and METHODS: Forty patients (mean age, 58.9 ± 13.8 years) with intracranial ICA lesions were prospectively examined by using TCCS and DSA. Two standard TCCS coronal imaging planes were used to evaluate the intracranial ICA. In addition, a control group of 128 volunteers without cerebrovascular disease (mean age, 48.8 ± 15.9 years) was investigated to establish standard velocity values.RESULTS: DSA confirmed 96 stenoses and 8 occlusions of the intracranial ICA in the study population. In 9% and 7% of cases, stenosis confined to the C1 or C5 segment was >50% and 70%, respectively. Receiver-operating curves demonstrated cutoff values for >70% stenosis in C1 when the peak systolic velocity (PSV) was >200 cm/s (specificity, 100%; sensitivity, 71%) or the C1/submandibular ICA index was >3 (specificity, 93%; sensitivity, 86%).CONCLUSIONS: TCCS is a reliable adjunctive method to detect and quantify significant stenosis of the intracranial ICA. The assessment of the C1/ICA index and peak systolic velocities maximizes the diagnostic accuracy of C1 stenosis to >70% when extracranial ICA stenosis coexists. Further studies need to be performed to compare the diagnostic accuracies of MR angiography and TCCS with that of DSA.

Detection of atherosclerotic narrowing of intracranial cerebral arteries is important in stroke management and aids in the identification of patients with high risk for vascular events.^1–3 Ischemic stroke due to atherosclerosis of intracranial large arteries has been reported in approximately 8%–29% of adults in general, with a higher prevalence in African and Asian populations.^4–6 The intracranial internal carotid artery (ICA) is the most common location for intracranial stenosis of >50%; such cases compose up to 49% of all intracranial artery stenoses.^1,7 Patients with severe (≥70%) intracranial stenosis have a higher risk of stroke than patients with moderate (50%–69%) intracranial stenosis.⁸ Treatment of significant stenosis relies on antiplatelet and antithrombotic agents as well as on aggressive lipid-lowering therapies.^9,10 Endovascular treatments involving angioplasty for 50%–99% ICA stenosis have also been applied but are considered experimental approaches in need of validation by controlled studies.^11–13Because the course of intracranial ICA is complicated due to its tortuosity and variability, classification of this portion of the vessel may differ between authors,^14–16 in turn complicating interpretation of the data. The “gold standard” used to assess the intracranial ICA remains digital subtraction angiography (DSA). DSA is usually performed only after noninvasive imaging procedures, such as MR angiography (MRA) and, to a lesser degree, conventional transcranial Doppler (TCD) sonography, have suggested intracranial stenosis. With TCD sonography, intracranial ICA stenosis is considered when flow velocities exceed normal values and/or exhibit abnormal flow patterns. Unlike cases of extracranial ICA disease, stenosis gradation of the intracranial ICA has not been calculated.^17,18 With MRA, intracranial ICA stenosis in the C5 as well as the C3 and C1 segments is frequently indicated by flow-void artifacts, especially when using time-of-flight sequences, because of the inherent signal-intensity loss of parallel imaging, which can only be compensated in part by the use of MR imaging contrast agents.¹⁹ Due to these MRA artifacts, calculation of ICA stenosis gradation is difficult, and semiquantitative scales, rather than percentages of stenosis, are frequently used to describe the lesion.²⁰Although the criteria for detecting significant (>50%) stenosis of basal cerebral arteries has been defined for transcranial color-coded sonography (TCCS),^21–24 little data can be found on grading intracranial ICA stenosis. The aim of this study was to elaborate the TCCS criteria for detection and quantification of significant intracranial ICA stenosis and to correlate them with conventional DSA criteria as the standard of reference.     

Transcranial color-coded duplex sonography of the carotid siphon: the coronal approach

Transcranial color-coded sonography can assist in the assessment of the carotid siphon segments C1 and C5 employing two standardized coronal image planes. In 32 volunteers mean velocities in the C1 and C5 were 41+/-16 and 30+/-10 (cm/s+/-S.D.), pulsatility indices (PI) 0.92+/-0.22 and 0.93+/-0.27, and resistance indices (RI) 0.58+/-0.08 and 0.55+/-0.12, respectively. Concluding, this technique is useful in assessing the carotid siphon with the most robust parameters being PI and RI requiring further validation by the "gold standard" angiography.     

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.     

Transcranial color-coded duplex sonography in the evaluation of collateral flow through the circle of Willis.

PURPOSETo determine the sensitivity, specificity, and positive and negative predictive values of transcranial color-coded duplex sonographic (TCCD) evaluation of cross flow through the anterior (ACoA) and posterior (PCoA) communicating arteries in patients with occlusive cerebrovascular disease.METHODSWe studied prospectively 132 patients (37 women, 95 men; mean age, 60 years) with stenoses of more than 69% reduction in vessel diameter (n = 93) and occlusions (n = 52) of the internal carotid artery, and three occlusions of the basilar artery. The sonographer was aware of extracranial sonographic findings but was blinded to the results of cerebral angiography.RESULTSNine patients (7%) with thick bones preventing transtemporal insonation and three patients (3%) with occlusions of the middle (n = 3) and anterior (n = 1) cerebral arteries were excluded. Sensitivity of TCCD for detection of collateral flow through the ACoA in patients with occlusive carotid artery disease was 98%, specificity was 100%, positive predictive value was 100%, and negative predictive value was 98%. The corresponding values for the PCoA were 84%, 94%, 94%, and 84%, respectively. All three functional PCoAs were identified in patients with occluded basilar arteries.CONCLUSIONTCCD is a valuable method for noninvasive evaluation of cross flow through the ACoA in patients with adequate sonographic windows. However, TCCD evaluation of cross flow through the PCoA is less reliable, because hemodynamic criteria may cause falsely positive and falsely negative results.     

Transcranial colour-coded duplex sonography of cerebral arteriovenous malformations

A transcranial colour-coded duplex sonography (TCCD) study was performed to evaluate the sensitivity of detection and the feasibility of visualising details of cerebral arteriovenous malformations (AVMs). We prospectively examined 15 patients with 2 large (> 4 cm), 7 medium-size (2–4 cm) and 6 small (< 2 cm) radiologically proven supratentorial AVMs of the brain using TCCD. A feeding vessel was diagnosed if the velocities and/or the relative interhemisphere velocity difference between feeding and non-feeding anterior, middle and posterior cerebral arteries were more than two standard deviations above the means of 136 age- and sex-matched normals. The sonographer was blinded to the results of cerebral angiography. Using TCCD it was possible to detect all large and medium-size lesions, and 4 of 6 small ones, because 23 of 29 (79 %) feeding arteries showed abnormal haemodynamics. In addition, 8 of 46 (17 %) feeding branches of cerebral arteries were shown. However, all but 2 large draining veins and sinus were not detected. In view of the availability of MRI, MRA and angiography, TCCD is not the method of choice in screening for cerebral AVMs. However, careful assessment of the velocities in the intracranial arteries permits incidental detection of cerebral AVMs and characterisation of the haemodynamics in the feeding arteries. Received: 1 March 1995 Accepted: 23 January 1996     

Venous incompetence in erectile dysfunction: evaluation with color-coded duplex sonography and cavernosometry/-graphy

The purpose of this study was to assess the accuracy of multi-parameter measurements with color-coded duplex sonography (CCDS) for the diagnosis of venous leakage in patients with erectile dysfunction. Sixty patients with repeated unsatisfactory reactions after intracavernous injection of vasoactive substances underwent CCDS. Following intracavernous injection of prostaglandin E₁, peak systolic velocity (PSV), enddiastolic velocity (EDV), time averaged velocity (TAV), resistance index (RI), and pulsatility index (PI) were measured in the cavernous arteries over 30 min (one measurement per minute). The results were compared with independent measurements based on dynamic pharmaco-cavernosometry/cavernosography (DPCC). Dynamic pharmaco-cavernosometry/cavernosography revealed venous leakage in 33 patients. Of 48 patients with normal PSV ( > 25 cm/s), 25 had veno-occlusive dysfunction and the remainder presented normal venous function. No statistically significant differences between these groups were found in EDV, RI, and PI measurements. In contrast, differences in TAV were significant between patients with (mean 9.4 ± 4.6 cm/s) and without venous leakage (mean 5.5 ± 2.2 cm/s; p = 0.001). Analysis of relative frequencies revealed a broad overlap of EDV, TAV, RI, and PI measurements between both groups. Sensitivities and specificities determined from receiver-operating-characteristic curves were > 80 % and > 50 % for a TAV threshold of 5 cm/s, and an RI threshold of 1.0. Measurements of EDV, TAV, RI, and PI in patients with repeated unsatisfactory reactions on intracavernous prostaglandin injection are poor predictors of venous leakage and should not replace DPCC in the investigation of vasculogenic impotence. Received: 27 February 1998; Revision received: 3 June 1998; Accepted: 5 June 1998     

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.     

Comparison of transcranial color-coded duplex sonography and cranial CT measurements for determining third ventricle midline shift in space-occupying stroke.

BACKGROUND AND PURPOSE: Transcranial color-coded duplex sonography (TCCS) allows the noninvasive, easily reproducible measurement of midline dislocation (MLD) of the third ventricle in space-occupying stroke, even in critically ill patients. However, the method has been validated only in a small number of subjects. The aim of this study was to test the method under clinical conditions. METHODS: In 61 prospectively recruited patients (mean age, 62+/-15 years) with supratentorial ischemic infarction or intracranial hemorrhage, the sonographic measurement of MLD was compared with cranial CT data in a 12-hour time window. Subgroup analysis was also undertaken for comparing TCCS and cranial CT measurements within a 3-hour time window. RESULTS: One hundred twenty-two data pairs of TCCS and cranial CT MLD measurements were correlated within the 12-hour time window. TCCS and cranial CT measurements of MLD correlated both in the total patient group and in the different subgroups with coefficients of over 0.9. The 2-SD confidence interval of the difference between the TCCS measurements and the respective means of both methods in the total patient collective was +/-1.78 mm. CONCLUSION: TCCS provides a noninvasive, easily reproducible and reliable method for monitoring MLD of the third ventricle in stroke patients. It is particularly suitable for critically ill patients who are not fit for transportation.     

Thrombosis of upper extremity thoracic inlet veins: diagnosis with duplex Doppler sonography

Duplex Doppler sonography of the axillary, subclavian, internal jugular, and brachiocephalic veins was performed in 20 normal volunteers and in a series of 22 consecutive patients with suspected venous thrombosis. When normal, these vessels had hypoechoic or anechoic lumina, sharply echogenic walls, and characteristic Doppler flow patterns that varied with changes in intrathoracic pressure. Most thrombosed vessels had poorly defined walls and echogenic lumina. All had absent flow on Doppler analysis. Duplex Doppler sonography was positive in all 10 patients subsequently shown to have venous thrombosis by venography or CT. One false-positive result occurred in a technically limited study. Sonography has the advantages of portability, ease of performance, and high patient acceptance. Duplex Doppler has advantages over either continuous-wave Doppler or imaging sonography alone. Our experience suggests that duplex Doppler sonography should be the initial diagnostic study in evaluating suspected thrombosis of the upper extremity thoracic inlet veins.     

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.     

Middle cerebral artery spasm after subarachnoid hemorrhage: detection with transcranial color-coded duplex US

PURPOSE: To prospectively determine the accuracy of transcranial color-coded duplex ultrasonography (US) used alone and in conjunction with carotid artery US for diagnosis of middle cerebral artery (MCA) spasm, with intraarterial digital subtraction angiography (DSA) used as the reference standard. MATERIALS AND METHODS: The institutional ethics committee approved the study. Each patient, or members of the patient's family, gave informed consent. One hundred twenty consecutive patients (64 women, 56 men; mean age, 45.5 years +/- 13.6 [standard deviation]) were routinely referred for DSA after subarachnoid hemorrhage. Vasospasm was graded as mild (< or =25% reduction in vessel diameter), moderate (>25% to 50% reduction), or severe (>50% reduction). US was performed 2 hours or less before angiography. The ratio of flow velocity in the middle cerebral artery (V(MCA)) to flow velocity in the ipsilateral extracranial internal carotid artery (V(ICA)) was calculated. Diagnostic accuracy was evaluated by calculating the area under the receiver operating characteristic curve (Az). The significance of the difference between the two Az values (for US vs DSA) was determined by using the z test with correction for correlated data. RESULTS: Nine of 120 patients were excluded because of inadequacy of acoustic windows in the squama of temporal bones. Spasm was mild in 17, moderate in 16, and severe in only nine of 222 arteries studied. Arteries with moderate or severe vasospasm were combined in one group. The best-performing parameters were peak systolic velocity and V(MCA)/V(ICA) ratio. Az values for these two parameters in diagnosis of moderate-to-severe vasospasm were 0.93 and 0.95, and in diagnosis of mild vasospasm, 0.90 and 0.91. Accuracy of the V(MCA)/V(ICA) ratio calculated on the basis of end-diastolic velocity for diagnosis of mild MCA narrowing was significantly better than that of end-diastolic MCA velocity alone (Az = 0.88 vs 0.84, P < .05). The stepwise approach with use of the V(MCA)/V(ICA) ratio after flow velocity measurements in the MCA resulted in a decreased number of false-negative findings in both vasospasm subgroups. The thresholds of highest efficiency were at a mean velocity of 94 and 108 cm/sec and a peak systolic V(MCA)/V(ICA) ratio of 3.6 and 3.9 for diagnosis of mild and moderate-to-severe vasospasm, respectively. CONCLUSION: Transcranial color-coded duplex US alone or in conjunction with carotid artery US has excellent accuracy for angiographic detection of vasospasm. Use of MCA velocity measurements and V(MCA)/V(ICA) ratio can increase the accuracy of Doppler US.     

Contrast-enhanced three-dimensional transcranial color-coded sonography of intracranial stenoses

BACKGROUND AND PURPOSE: Intracranial stenoses are associated with a considerable number of strokes each year. The clinical value of a workstation-based three-dimensional (3D) reconstruction system for transcranial color-coded sonography was evaluated in patients with intracranial stenosis or occlusion. METHODS: Twenty-six patients (13 men, 13 women; mean age, 57 years +/- 12 [SD]) with 36 intracranial stenoses or occlusions, as detected at two-dimensional (2D) color Doppler imaging (CDI) and digital subtraction angiography (DSA), underwent Levovist-enhanced power Doppler imaging (PDI), with subsequent 3D reconstruction. A workstation connected to a magnetic sensor capable of spatial localization of the probe was used to reconstruct 3D images of the circle of Willis from serial PDI images. RESULTS: At DSA, seven (19%) stenoses were estimated to less than 50%, 24 (67%) were 50% or more, and five (14%) were occluded. DSA and 3D-PDI estimates of the degree of stenosis agreed in 33 cases (92%), with a weighted kappa value of 0.86. Disagreement occurred with two subtotal basilar artery stenoses and one subtotal middle cerebral artery stenosis, which were evaluated as being complete occlusions at 3D-PDI. Interobserver agreement between two experienced 3D investigators in estimating the percentage of stenosis was high (correlation coefficient,.98). CONCLUSION: 3D-PDI enables the investigator to reconstruct virtually any arbitrary viewing angle. Compared with conventional CDI, 3D-PDI offers easier spatial assessment of intracranial stenoses, and its findings are sufficiently correlated with angiographic findings. Because different investigators can postprocess the same 3D data, improving reproducibility and reducing investigator dependency in transcranial color-coded sonography may be possible.     

经颅彩色双功超声在脑血管疾病中的临床应用和进展

经颅彩色双功超声是一种新型、无创的超声诊断仪,高空间分辨率显示颅内血管和脑实质的结构,笔者查阅了近年来相关文献,主要综述经颅彩色多普勒血流显像在颅脑血管疾病中的诊断价值,同时讨论二维经颅超声的应用及新的实验性显像技术。     

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.     

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.