Cerebral angiographic risk in mild cerebrovascular disease

Routine Angiography is Not Indicated in Patients with Blunt Cerebrovascular Injury

OBJECTIVES

Blunt cerebrovascular injury (BCVI) refers to blunt, traumatic injury of the carotid or vertebral arteries. Prompt treatment of BCVI is imperative due to the risk of long-term neurological injuries. Treatment depends in part on injury severity according to the Biffl grade. Despite evidence confirming the safety and accuracy of axial imaging, confirmatory digital subtraction angiography (DSA) is still performed with diagnostic and therapeutic intent. We hypothesized that routine invasive DSA is not indicated for patients with low-grade BCVI for diagnosis or follow up and is associated with unnecessary costs and complications.

METHODS

We performed a single-center, restrospective study of the diagnosis and management of patients with BCVI at a level 1 trauma center. Patients with BCVI were identified by ICD 9/10 codes from the institutional trauma registry from January 1, 2010-December 31st, 2021. We analyzed the charts patients with BCVI of the vertebral and carotid arteries collected demographics and characteristics management. Descriptive statistics were performed. Univariate analysis was performed to determine differences between DSA and no-DSA patients. Correlation of noninvasive imaging and DSA results were calculated.

RESULTS

251 patients with BCVI were diagnosed by CTA (178 vertebral (71%), 67 (26%) carotid, 6 (2%) both). Consulted services were neurosurgery (96%), vascular surgery (2%), or both (2%). DSA was performed in 164 patients (43 Carotid, 116 Vertebral, 5 both), all performed by neurosurgery, the majority (72%) done within 24 hours from diagnosis. Most patients (98%) were asymptomatic with 5 patients presenting with stroke-like symptoms and only one of these patients underwent DSA for hemiparesis. Intervention was done in 9 patients. All patients were treated with antiplatelets (81%) or anticoagulation (17%). BCVI injury grade correlated between CTA/MRA and DSA in the majority of patients 88 (79%); downgraded in 15 (13%) patients where no BCVI was appreciated on DSA and upgraded in 9 (8%) patients for vessel occlusion or pseudoaneurysm formation. No management changes resulted from DSA. DSA-related complications included groin access complications (4.2%) and iatrogenic cerebral artery injury (1.8%). Delayed intervention was required in one patient for a growing pseudoaneurysm noted on non-invasive imaging.

CONCLUSIONS

Routine DSA following CTA does not change management of BCVI patients. DSA is associated with low but significant rates of complications for diagnosing BCVI. An algorithm that incorporates follow-up non-invasive imaging with duplex ultrasound or CTA may be indicated to identify patients who would benefit from DSA.

Diagnostic yield of cerebral angiography for intracranial hemorrhage in young patients: A single-center retrospective analysis

BackgroundIntracranial hemorrhage (ICH) secondary to hypertension (HTN) classically occurs in the basal ganglia, cerebellum, or pons. Vascular lesions such as aneurysms or arteriovenous malformations (AVMs) are more common in younger patients. We investigated the utility of diagnostic subtraction angiography (DSA) in young hypertensive patients with non-lobar ICH.MethodsA retrospective review (2013-2022) identified young (18-60 years) patients who underwent DSA for ICH. HTN history, ICH location, presence/absence of subarachnoid hemorrhage (SAH), and computed tomography angiography (CTA) findings were collected. The main outcome was DSA-positivity, defined as presence of an AVM, aneurysm, Moyamoya disease, reversible cerebral vasoconstriction syndrome, or dural arteriovenous fistula on DSA.ResultsTwo hundred sixty patients were included, and the DSA-positivity rate was 19%.DSA-positivity was lower in hypertensive patients with ICHs in the cerebellum, pons, or basal ganglia compared to the rest of the patient sample (9% vs 26%, p = 0.0002, Fisher's exact test). We developed the ICH-Angio score (0-5 points) based on CTA findings, ICH location, HTN history, and presence of SAH to predict risk of underlying vascular lesions. DSA-positivity was lower in those with a score of 0 (0/62; 0%) compared to a score of 1 (5/52; 10%), 2 (17/48; 35%), 3 (10/20; 50%), 4 (5/6; 83%), or 5 (3/3; 100%).ConclusionThe ICH-Angio score was able to non-invasively rule out an underlying vascular etiology for ICH in up to one-third of patients. HTN, ICH location, CTA findings, and associated SAH can identify patients at low risk for harboring underlying vascular lesions.

Highly compressed SENSE accelerated relaxation-enhanced angiography without contrast and triggering (REACT) for fast non-contrast enhanced magnetic resonance angiography of the neck: Clinical evaluation in patients with acute ischemic stroke at 3 tesla

BACKGROUND AND PURPOSE

Long acquisition times limit the feasibility of established non-contrast-enhanced MRA (non-CE-MRA) techniques. The purpose of this study was to evaluate a highly accelerated flow-independent sequence (Relaxation-Enhanced Angiography without Contrast and Triggering [REACT]) for imaging of the extracranial arteries in acute ischemic stroke (AIS).

MATERIALS AND METHODS

Compressed SENSE (CS) accelerated (factor 7) 3D isotropic REACT (fixed scan time: 01:22 min, reconstructed voxel size 0.625 × 0.625 × 0.75 mm3) and CE-MRA (CS factor 6, scan time: 1:08 min, reconstructed voxel size 0.5 mm3) were acquired in 76 AIS patients (69.4 ± 14.3 years, 33 females) at 3 Tesla. Two radiologists assessed scans for the presence of internal carotid artery (ICA) stenosis and stated their diagnostic confidence using a 5-point scale (5 = excellent). Vessel quality of cervical arteries as well as the impact of artifacts and image noise were scored on 5-point scales (5 = excellent/none). Apparent signal- and contrast-to-noise ratios (aSNR/aCNR) were measured for the common carotid artery (CCA) and ICA (C1-segment).

RESULTS

REACT provided a sensitivity of 88.5% and specificity of 100% for clinically relevant (≥50%) ICA stenosis with substantial concordance to CE-MRA regarding stenosis grading (Cohen's kappa 0.778) and similar diagnostic confidence (REACT: mean 4.5 ± 0.4 vs. CE-MRA: 4.5 ± 0.6; P = 0.674). Presence of artifacts (3.6 ± 0.5 vs. 3.5 ± 0.7; P = 0.985) and vessel quality (all segments: 3.6 ± 0.7 vs. 3.8 ± 0.7; P = 0.004) were comparable between both techniques with REACT showing higher scores at the CCA (4.3 ± 0.6 vs. 3.8 ± 0.9; P < 0.001) and CE-MRA at V2- (3.3 ± 0.5 vs. 3.9 ± 0.8; P < 0.001) and V3-segments (3.3 ± 0.5 vs. 4.0 ± 0.8; P < 0.001). For all vessels, REACT showed a lower impact of image noise (3.8 ± 0.6 vs. 3.6 ± 0.7; P = 0.024) while yielding higher aSNR (52.5 ± 15.1 vs. 37.9 ± 12.5; P < 0.001) and aCNR (49.4 ± 15.0 vs. 34.7 ± 12.3; P < 0.001) for all vessels combined.

CONCLUSIONS

In patients with acute ischemic stroke, highly accelerated REACT provides an accurate detection of ICA stenosis with vessel quality and scan time comparable to CE-MRA.

Detection of moderate to severe middle cerebral artery atherosclerotic stenosis in stroke patients: Transcranial color-coded duplex sonography versus computed tomography angiography

Background

Intracranial atherosclerotic stenosis is a common cause of ischemic cerebrovascular events and is associated with a high risk of stroke recurrence. This study aimed to assess the diagnostic accuracy of transcranial color-coded duplex sonography for moderate-to-severe middle cerebral artery stenosis in stroke patients.

Methods

A retrospective analysis was carried out, including 31 patients aged ⩾18 years hospitalized for ischemic cerebrovascular event in whom middle cerebral artery stenosis ⩾30% was identified on computed tomography angiography. Transcranial color-coded duplex sonography findings were compared to the degree of stenosis blindly identified on the computed tomography angiography used as the reference method.

Results

Overall, 27 patients had M1 stenosis and the other 4 had M2 stenosis. To detect M2 stenosis ⩾ 50% and ⩾ 70%, stenotic to pre-stenotic ratio ⩾ 2 and ⩾ 3 had a sensitivity of 100%, respectively. To detect M1 stenosis ⩾ 70%, peak systolic velocity ⩾ 300 cm/s had a sensitivity of 53.8% and specificity of 85.7% with area under the receiver-operating characteristic curve of 0.753 (95% confidence interval: 0.568-0.938; p = 0.026), and stenotic to pre-stenotic ratio ⩾ 3 had a sensitivity of 84.6% and a specificity of 78.6% (area under the curve = 0.854; 95% confidence interval: 0.707-1; p = 0.002). Middle cerebral artery/anterior cerebral artery velocity ratio < 0.7 had a sensitivity of 57.1% and specificity of 90% to detect dampened pre-stenotic flow in middle cerebral artery secondary to downstream M1 stenosis ⩾ 70% (area under the curve = 0.800; 95% confidence interval: 0.584-1; p = 0.040).

Conclusion

This study showed that stenotic to pre-stenotic ratio ⩾ 3 was more sensitive than peak systolic velocity ⩾ 300 cm/s to screen M1 stenosis ⩾ 70%. Middle cerebral artery/anterior cerebral artery ratio < 0.7 was a good indirect sign to detect dampened pre-stenotic flow due to M1 stenosis ⩾ 70%.

Intraoperative fusion imaging during transcarotid artery revascularization

Background

Transcarotid artery revascularization (TCAR) with reverse-flow neuroprotection has emerged as an alternative to transfemoral carotid artery stenting and carotid endarterectomy. However, it requires fluoroscopic guidance, exposing the patient and surgeon to radiation. Although fusion-guided endovascular aneurysm repair has been demonstrated to significantly decrease this radiation risk, not much is known about similar outcomes for TCAR. The purpose of this study is to evaluate the outcomes at a single institution using fusion-guided imaging during TCAR compared with regional TCAR cases in the Vascular Quality Initiative (VQI) registry without fusion imaging.

Methods

A retrospective analysis was conducted of data collected from all patients undergoing TCAR with fusion-guided imaging (TCAR-F) at our hospital and patients undergoing TCAR alone within the VQI database. The primary outcomes included the total operative time, dose area product, fluoroscopy time, contrast usage, and flow-reversal time. The demographics and preoperative risk factors were also assessed in both groups. Continuous outcomes were compared using the Welch t test. Categorical outcomes were compared using the Fisher exact test.

Results

A total of 30 TCAR-F cases (January 2019 to May 2022) at our institution were compared against the regional VQI dataset (n = 2535). The TCAR-F cases had a lower dose area product (5.67 vs 93.1 Gy cm2; P < .0001), shorter fluoroscopy time (8.07 vs 16.4 minutes; P < .0001), and less contrast usage (13.49 vs 76.7 mL; P < .0001) compared with the regional averages of the same. The TCAR-F cases had a longer total operative time (117.3 vs 80.9 minutes; P < .0001) and flow-reversal time (14.4 vs 11.7 minutes; P = .025) compared with the regional cases.

Conclusions

The results from this pilot study comparing TCAR-F patients at a single institution with VQI regional TCAR patients suggest that TCAR-F cases use less radiation and contrast compared with TCAR without fusion imaging. Fusion-guided imaging might provide radiation protection to both patients and surgeons and decrease contrast usage for the patient.

Assessment of extracranial carotid artery disease using digital twins - A pilot study

To improve risk stratification in extracranial internal carotid artery disease (CAD), patients who would benefit maximally from revascularization must be identified. In cardiology, the fractional flow reserve (FFR) has become a reference standard for evaluating the functional severity of coronary artery stenosis, and noninvasive surrogates thereof relying on computational fluid dynamics (CFD) have been developed. Here, we present a CFD-based workflow using digital twins of patients' carotid bifurcations derived from computed tomography angiography for the noninvasive functional assessment of CAD. We reconstructed patient-specific digital twins of 37 carotid bifurcations. We implemented a CFD model using common carotid artery peak systolic velocity (PSV) acquired with Doppler ultrasound (DUS) as inlet boundary condition and a two-element Windkessel model as oulet boundary condition. The agreement between CFD and DUS on the PSV in the internal carotid artery (ICA) was then compared. The relative error for the agreement between DUS and CFD was 9% ± 20% and the intraclass correlation coefficient was 0.88. Furthermore, hyperemic simulations in a physiological range were feasible and unmasked markedly different pressure drops along two ICA stenoses with similar degree of narrowing under comparable ICA blood flow. Hereby, we lay the foundation for prospective studies on noninvasive CFD-based derivation of metrics similar to the FFR for the assessment of CAD.

Duplex ultrasound for diagnosing symptomatic carotid stenosis in the extracranial segments

BACKGROUND

Carotid artery stenosis is an important cause of stroke and transient ischemic attack. Correctly and rapidly identifying patients with symptomatic carotid artery stenosis is essential for adequate treatment with early cerebral revascularization. Doubts about the diagnostic value regarding the accuracy of duplex ultrasound (DUS) and the possibility of using DUS as the single diagnostic test before carotid revascularization are still debated.

OBJECTIVES

To estimate the accuracy of DUS in individuals with symptomatic carotid stenosis verified by either digital subtraction angiography (DSA), computed tomography angiography (CTA), or magnetic resonance angiography (MRA).

SEARCH METHODS

We searched CRDTAS, CENTRAL, MEDLINE (Ovid), Embase (Ovid), ISI Web of Science, HTA, DARE, and LILACS up to 15 February 2021. We handsearched the reference lists of all included studies and other relevant publications and contacted experts in the field to identify additional studies or unpublished data.

SELECTION CRITERIA

We included studies assessing DUS accuracy against an acceptable reference standard (DSA, MRA, or CTA) in symptomatic patients. We considered the classification of carotid stenosis with DUS defined with validated duplex velocity criteria, and the NASCET criteria for carotid stenosis measures on DSA, MRA, and CTA. We excluded studies that included < 70% of symptomatic patients; the time between the index test and the reference standard was longer than four weeks or not described, or that presented no objective criteria to estimate carotid stenosis.

DATA COLLECTION AND ANALYSIS

The review authors independently screened articles, extracted data, and assessed the risk of bias and applicability concerns using the QUADAS-2 domain list. We extracted data with an effort to complete a 2 × 2 table (true positives, true negatives, false positives, and false negatives) for each of the different categories of carotid stenosis and reference standards. We produced forest plots and summary receiver operating characteristic (ROC) plots to summarize the data. Where meta-analysis was possible, we used a bivariate meta-analysis model.

MAIN RESULTS

We identified 25,087 unique studies, of which 22 were deemed eligible for inclusion (4957 carotid arteries). The risk of bias varied considerably across the studies, and studies were generally of moderate to low quality. We narratively described the results without meta-analysis in seven studies in which the criteria used to determine stenosis were too different from the duplex velocity criteria proposed in our protocol or studies that provided insufficient data to complete a 2 × 2 table for at least in one category of stenosis. Nine studies (2770 carotid arteries) presented DUS versus DSA results for 70% to 99% carotid artery stenosis, and two (685 carotid arteries) presented results from DUS versus CTA in this category. Seven studies presented results for occlusion with DSA as the reference standard and three with CTA as the reference standard. Five studies compared DUS versus DSA for 50% to 99% carotid artery stenosis. Only one study presented results from 50% to 69% carotid artery stenosis. For DUS versus DSA, for < 50% carotid artery stenosis, the summary sensitivity was 0.63 (95% confidence interval [CI] 0.48 to 0.76) and the summary specificity was 0.99 (95% CI 0.96 to 0.99); for the 50% to 69% range, only one study was included and meta-analysis not performed; for the 50% to 99% range, the summary sensitivity was 0.97 (95% CI 0.95 to 0.98) and the summary specificity was 0.70 (95% CI 0.67 to 0.73); for the 70% to 99% range, the summary sensitivity was 0.85 (95% CI 0.77 to 0.91) and the summary specificity was 0.98 (95% CI 0.74 to 0.90); for occlusion, the summary sensitivity was 0.91 (95% CI 0.81 to 0.97) and the summary specificity was 0.95 (95% CI 0.76 to 0.99). For sensitivity analyses, excluding studies in which participants were selected based on the presence of occlusion on DUS had an impact on specificity: 0.98 (95% CI 0.97 to 0.99). For DUS versus CTA, we found two studies in the range of 70% to 99%; the sensitivity varied from 0.57 to 0.94 and the specificity varied from 0.87 to 0.98. For occlusion, the summary sensitivity was 0.95 (95% CI 0.80 to 0.99) and the summary specificity was 0.91 (95% CI 0.09 to 0.99). For DUS versus MRA, there was one study with results for 50% to 99% carotid artery stenosis, with a sensitivity of 0.88 (95% CI 0.70 to 0.98) and specificity of 0.60 (95% CI 0.15 to 0.95); in the 70% to 99% range, two studies were included, with sensitivity that varied from 0.54 to 0.99 and specificity that varied from 0.78 to 0.89. We could perform only a few of the proposed sensitivity analyses because of the small number of studies included.

AUTHORS' CONCLUSIONS

This review provides evidence that the diagnostic accuracy of DUS is high, especially at discriminating between the presence or absence of significant carotid artery stenosis (< 50% or 50% to 99%). This evidence, plus its less invasive nature, supports the early use of DUS for the detection of carotid artery stenosis. The accuracy for 70% to 99% carotid artery stenosis and occlusion is high. Clinicians should exercise caution when using DUS as the single preoperative diagnostic method, and the limitations should be considered. There was little evidence of the accuracy of DUS when compared with CTA or MRA. The results of this review should be interpreted with caution because they are based on studies of low methodological quality, mainly due to the patient selection method. Methodological problems in participant inclusion criteria from the studies discussed above apparently influenced an overestimated estimate of prevalence values. Most of the studies included failed to precisely describe inclusion criteria and previous testing. Future diagnostic accuracy studies should include direct comparisons of the various modalities of diagnostic tests (mainly DUS, CTA, and MRA) for carotid artery stenosis since DSA is no longer considered to be the best method for diagnosing carotid stenosis and less invasive tests are now used as reference standards in clinical practice. Also, for future studies, the participant inclusion criteria require careful attention.

Accelerated Two-Point Dixon MR Angiography Improves Diagnostic Performance for Cervical Artery Diseases

BACKGROUND

Nonenhanced MR angiography (MRA) studies are often used to manage acute and chronic large cervical artery disease, but lengthy scan times limit their clinical usefulness.

PURPOSE

To develop an accelerated cervical MRA and test its diagnostic performance.

STUDY TYPE

Prospective.

POPULATION

Patients with cervical artery disease (n = 32, 17 males).

FIELD STRENGTH/SEQUENCE

3.0 T; accelerated two-point Dixon three-dimensional Cartesian spoiled gradient-echo (FLEXA) and conventional time-of-flight MRA (cMRA) sequences.

ASSESSMENT

All patients underwent FLEXA (1'28″) and cMRA (6'47″) acquisitions. Quantitative evaluation (artery-to-background signal ratio and a blur metric) and qualitative evaluation using diagnostic performance measured by the sensitivity, specificity, and positive/negative predictive values (PPV/NPV), and vessel and plaque visualization scores from three board-certified radiologists' (with 10, 11, and 12 years of experience) independent readings using maximum intensity projection (MIP) for luminal diseases and axial images for plaque. The reference standards were contrast-enhanced angiography and fat-saturated T1-weighted images, respectively.

STATISTICAL TESTS

All measures were compared between FLEXA and cMRA using the paired t, Wilcoxon signed-rank, McNemar's, or chi-squared test, as appropriate. Interreader agreement was assessed using Cohen's κ. P < 0.05 was considered statistically significant.

RESULTS

The artery-to-background signal ratio was significantly higher for FLEXA (FLEXA: 7.20 ± 1.63 [fat]; 4.26 ± 0.52 [muscle]; cMRA: 2.57 ± 0.49 [fat]), while image blurring was significantly less (FLEXA: 0.24 ± 0.016; cMRA: 0.30 ± 0.029). In luminal disease detection, sensitivity (FLEXA: 0.97/0.91/0.91; cMRA:0.71/0.69/0.63), specificity (FLEXA: 0.98/0.93/0.98; cMRA:0.93/0.85/0.92), PPV (FLEXA: 0.92/0.86/0.86; cMRA: 0.64/0.5/0.58), and NPV (FLEXA: 0.99/0.98/0.98; cMRA: 0.92/0.91/0.9) were significantly higher for FLEXA. interreader agreement was substantial to almost perfect for FLEXA (κ = 0.82/0.86/0.78) and moderate to substantial for cMRA (κ = 0.67/0.56/0.57). MIP visualization scores were significantly higher for FLEXA, with substantial to almost perfect interreader agreement (FLEXA: κ = 0.83/0.86/0.82; cMRA: κ = 0.89/0.79/0.79). In plaque detection, sensitivity (FLEXA: 0.9/0.9/0.7; cMRA: 0.3/0.6/0.2) and specificity (FLEXA: 1/0.87/1; cMRA: 0.93/0.63/0.97) were significantly higher for FLEXA in two of three readers. The interreader plaque detection agreement was fair to substantial (FLEXA: κ = 0.63/0.69/0.48; cMRA: κ = 0.21/0.45/0.20). Side-by-side plaque and vessel wall visualization was superior for FLEXA in all readers, with moderate to substantial interreader agreement (plaque: κ = 0.73/0.73/0.77; vessel wall: κ = 0.57/0.40/0.39).

DATA CONCLUSION

FLEXA enhanced visualization of the cervical arterial system and improved diagnostic performance for luminal abnormalities and plaques in patients with cervical artery diseases.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY STAGE: 2.

Morphometric study regarding ophthalmic and internal carotid arteries utilizing computed tomography angiography

The aim of the present study was to accurately measure the diameter of the ophthalmic artery (OA) and investigate whether bilateral variations in diameter can be recorded in relation to patient age and sex. A retrospective study including 80 computed tomography angiographic (CTA) examinations and a total of 160 arteries was conducted to demonstrate the morphometric aspects of the OAs analyzed bilaterally by CTA examinations, while considering the references of the internal carotid artery (ICA) caliber. Precise measurements performed on the OA and the ICA below and above the ophthalmic emergence revealed an OA diameter of 1.38±0.24 mm and a narrowing of the ICA between the origin of the OA of 1.5±0.25 mm. Variations in the OA and the ICA calibers were studied in subjects with normal cervical vasculature on CTA. After a thorough statistical study, variations in OA and ICA caliber on each side were identified, between both sex and age-related groups, revealing morphometric parameters of the OA in relation to the ICA.

Generally applicable window settings of low-keV virtual monoenergetic reconstructions in dual-layer CT-angiography of the head and neck

Background

Increased vessel contrast in low-keV virtual monoenergetic images (VMI) in spectral detector CT angiography of the head and neck requires adaption of window settings. Aim of this study was to define generally applicable window settings of low-keV VMI.

Methods

Two radiologists determined ideal subjective window settings for VMI_{40-70 keV} in 54 patients. To obtain generally applicable window settings, center and width values were modeled against the attenuation of the internal carotid artery (HUICA). This modeling was performed with and without respect to keV. Subsequently, image quality of VMI_{40-70 keV} was assessed using the model-based determined window settings.

Results

With decreasing keV values, HUICA increased significantly in comparison to conventional images (CI) (P<0.05 for 40-60 keV). No significant differences between modelled and individually recorded window settings were found confirming validity of the obtained models (P values: 0.2-1.0). However, modelling with respect to keV was marginally less precise.

Conclusions

Window settings of low-keV VMI can be semi-automatically determined in dependency of the ICA attenuation in spectral detector CTA of the head and neck. The reported models are a promising tool to leverage the improved image quality of these images in clinical routine.

First in Man Pilot Feasibility Study in Extracranial Carotid Robotic-Assisted Endovascular Intervention

BACKGROUND

Robotic-assistance in endovascular intervention represents a nascent yet promising innovation.

OBJECTIVE

To present the first human experience utilizing robotic-assisted angiography in the extracranial carotid circulation.

METHODS

Between March 2019 and September 2019, patients with extracranial carotid circulation pathology presenting to Houston Methodist Hospital were enrolled.

RESULTS

A total of 6 patients met inclusion criteria: 5 underwent diagnostic angiography only with robotic-assisted catheter manipulation, while 1 underwent both diagnostic followed by delayed therapeutic intervention. Mean age was 51 +/- 17.5 yr. Mean anesthesia time was 158.7 +/- 37.9 min, mean fluoroscopic time was 22.0 +/- 7.3 min, and mean radiation dose was 815.0 +/- 517.0 mGy. There were no technical complications and no clinical deficits postprocedure. None of the cases required conversion to manual neurovascular intervention (NVI).

CONCLUSION

Incorporating robotic technology in NVI can enhance procedural technique and diminish occupational hazards. Its application in the coronary and peripheral vascular settings has established safety and efficacy, but in the neurovascular setting, this has yet to be demonstrated. This study presents the first in human feasibility experience of robotic-assisted NVI in the extracranial carotid circulation.

Transcranial Color-Coded Sonography Criteria for Moderate and Severe Middle Cerebral Artery Stenosis

This study aimed to establish optimal criteria for evaluation of moderate (50%-69%) and severe (70%-99%) middle cerebral artery (MCA) stenosis with transcranial color-coded sonography (TCCS). A total of 375 cases provided 409 TCCS/digital subtraction angiography vessel pairs. Peak systolic velocity (PSV), end-diastolic velocity (EDV) and mean flow velocity (MFV) of the MCA were measured. The stenotic/distal MFV ratios (SDRs) were calculated. With digital subtraction angiography as a reference, for 50%-69% MCA stenosis, the optimal combined criteria were PSV ≥180 cm/s (sensitivity 95.7%, specificity 64.9% and overall accuracy 69.7%); EDV ≥75 cm/s (90.0%, 66.4% and 68.7%); MFV ≥110 cm/s (95.7%, 64.0% and 69.4%); and SDR ≥2.5 (88.6%, 71.3% and 76.3%). Criteria for 70%-99% MCA stenosis were PSV ≥240 cm/s (93.5%, 89.9% and 85.5%); EDV ≥100 cm/s (96.8%, 89.0% and 87.3%); MFV≥160 cm/s (91.9%, 92.8% and 92.2%); and SDR ≥4 (87.1%, 92.2% and 91.4%). Parameters of the MCA detected by TCCS, especially SDR, may increase accuracy in diagnosis of 50%-69% and 70%-99% MCA stenosis.

MRI Characterization of Non-traumatic Intracerebral Hemorrhage in Young Adults

Background and Purpose: Non-traumatic intracerebral hemorrhage (ICH) in younger population is a relatively rare event but is associated with considerable mortality and poor functional outcome. Imaging plays a crucial role in determining the underlying cause and guide treatment of ICH. In up to 41% of patients in prior studies, the underlying cause remained elusive. However, the usage of MRI as part of diagnostic work-up was scanty. We aimed to analyze MRI findings of ICH in younger patients and assess specificity and sensitivity of MRI in detecting structural or local underlying causes of ICH.

Methods: We included patients aged 15–49 years with first-ever ICH identified from a prospective hospital discharge registry, 2000–2010. All study patients underwent MRI within 3 months of ICH. Imaging data was analyzed by a senior neuroradiologist blinded to final clinical diagnosis. We calculated the diagnostic accuracy of MRI in detecting structural/local underlying causes.

Results: Of our 116 patients (median age, 39; 67% males), structural/local causes were the leading causes of ICH (50.0%), and of these, bleeding cavernomas (23.3%) were the most frequent followed by arteriovenous malformations (12.9%), cerebral venous thrombosis (CVT) (7.8%), brain tumors (5.2%), and moyamoya disease (0.9%). Lobar location of ICH was more prevalent in younger patients. MRI was highly sensitive (90.0%; 95% confidence interval, 79.5–96.2%) for detection of structural/local causes compared with angiographic imaging (55.6%; 95% CI, 40.0–70.4%), while MRI was less specific (87.3%; 95% CI, 75.5–94.7%) for structural/local causes, compared with angiographic imaging (97.4%; 95% CI, 86.5–99.9%).

Conclusion: MRI was highly sensitive for the detection of structural and local causes underlying ICH in young adults. Thus, MRI should be considered in the diagnostic work-up of all young ICH patients to enable targeted secondary prevention.

Overcoming calcium blooming and improving the quantification accuracy of percent area luminal stenosis by material decomposition of multi-energy computed tomography datasets

Purpose: Conventional stenosis quantification from single-energy computed tomography (SECT) images relies on segmentation of lumen boundaries, which suffers from partial volume averaging and calcium blooming effects. We present and evaluate a method for quantifying percent area stenosis using multienergy CT (MECT) images. Approach: We utilize material decomposition of MECT images to measure stenosis based on the ratio of iodine mass between vessel locations with and without a stenosis, thereby eliminating the requirement for segmentation of iodinated lumen. The method was first assessed using simulated MECT images created with different spatial resolutions. To experimentally assess this method, four phantoms with different stenosis severity (30% to 51%), vessel diameters (5.5 to 14 mm), and calcification densities (700 to 1100    mgHA / cc ) were fabricated. Conventional SECT images were acquired using a commercial CT system and were analyzed with commercial software. MECT images were acquired using a commercial dual-energy CT (DECT) system and also from a research photon-counting detector CT (PCD-CT) system. Three-material-decomposition was performed on MECT data, and iodine density maps were used to quantify stenosis. Clinical radiation doses were used for all data acquisitions. Results: Computer simulation verified that this method reduced partial volume and blooming effects, resulting in consistent stenosis measurements. Phantom experiments showed accurate and reproducible stenosis measurements from MECT images. For DECT and two-threshold PCD-CT images, the estimation errors were 4.0% to 7.0%, 2.0% to 9.0%, 10.0% to 18.0%, and - 1.0 % to - 5.0 % (ground truth: 51%, 51%, 51%, and 30%). For four-threshold PCD-CT images, the errors were 1.0% to 3.0%, 4.0% to 6.0%, - 1.0 % to 9.0%, and 0.0% to 6.0%. Errors using SECT were much larger, ranging from 4.4% to 46%, and were especially worse in the presence of dense calcifications. Conclusions: The proposed approach was shown to be insensitive to acquisition parameters, demonstrating the potential to improve the accuracy and precision of stenosis measurements in clinical practice.

Ultrasonography for the diagnosis of extra-cranial carotid occlusion - diagnostic test accuracy meta-analysis

Background: The correct diagnosis of internal carotid artery (ICA) occlusion is crucial as it limits unnecessary intervention, whereas correct identification of patients with severe ICA stenosis is paramount in decision making and selecting patients who would benefit from intervention. We aimed to evaluate the accuracy of ultrasonography (US) in the diagnosis of ICA occlusion. Methods: We conducted a systematic review in compliance with the Preferred Reporting Items for a Systematic Review and Meta-analysis (PRISMA) of diagnostic test accuracy studies. We interrogated electronic bibliographic sources using a combination of free text and thesaurus terms to identify studies assessing the diagnostic accuracy of US in ICA occlusion. We used a mixed-effects logistic regression bivariate model to estimate summary sensitivity and specificity. We developed hierarchical summary receiver operating characteristic (HSROC) curves. Results: We identified 23 studies reporting a total of 5,675 arteries of which 722 were proven to be occluded by the reference standard. The reference standard was digital subtraction or cerebral angiography in all but two studies, which used surgery to ascertain a carotid occlusion. The pooled estimates for sensitivity and specificity were 0.97 (95% confidence interval (CI) 0.94 to 0.99) and 0.99 (95% CI 0.98 to 1.00), respectively. The diagnostic odds ratio was 3,846.15 (95% CI 1,375.74 to 10,752.65). The positive and negative likelihood ratio were 114.71 (95% CI 58.84 to 223.63) and 0.03 (95% CI 0.01 to 0.06), respectively. Conclusions: US is a reliable and accurate method in diagnosing ICA occlusion. US can be used as a screening tool with cross-sectional imaging being reserved for ambiguous cases.

Delivering the diluted contrast agent with saline via a spiral flow tube improves arterial enhancement for contrast enhancement of magnetic resonance angiography of the neck: A retrospective study

A contrast agent can be pushed by a saline solution more effectively through a spiral flow tube than through a conventional T-shaped tube in contrast-enhanced magnetic resonance angiography (CEMRA). To compare the degree of contrast enhancement and signal stability in the carotid artery by using CEMRA between a spiral flow tube and a T-shaped tube.A total of 100 patients were analyzed in this retrospective study. The first 50 patients underwent CEMRA of the carotid artery with the T-shaped tube, while the last 50 patients used the spiral flow tube. Gadoterate meglumine was diluted with saline to make a total volume of 20 mL. Injection was performed with a bolus rate of 2.5 mL/s for 8 seconds. Five regions of interest (ROIs) were placed on the contrast-enhanced area in each carotid artery and the signal intensity (SI) in the ROI was used for the analysis. The ROIs on the brain stem were also placed and the average SI in this ROI was used as a reference signal. The enhancement of the artery (Eartery) was calculated as a normalized signal using the following equation: Eartery = SI in the ROI of the carotid bifurcation/SI in the ROI of the brain stem. Signal homogeneity in the contrast-enhanced area (SHenhance) was assessed by calculating the coefficient of variation from the SI in the 5 ROIs. The value of SHenhance and Eartery between the data obtained from the spiral flow tube and the T-shaped tube were compared. P-values <.05 were considered significant.We found a significant difference in SHenhance between the data obtained from the spiral flow tube (0.20 ± 0.060) and the T-shaped tube (0.24 ± 0.056) (P = .001). The Eartery values significantly increased by 15% (spiral flow tube, median 14.1 with interquartile range [IQR] 11.8-15.4 vs T-shaped tube, median 12.3 IQR 11.3-14.0, P = .02) using the spiral flow tube.These findings suggest that, by using the Spiral flow tube, the homogeneity of the contrast-enhanced signal intensity in the carotid artery was significantly improved without decreasing the signal intensity in CEMRA.

Migraine and Non-Migraine Headaches Following Diagnostic Catheter-Based Cerebral Angiography

BACKGROUND AND OBJECTIVE

No reliable estimates of headaches following catheter-based cerebral angiography are available. We performed an observational cohort study to ascertain the frequency and type of headaches following catheter-based cerebral angiography.

MATERIALS AND METHODS

Consecutive patients who underwent cerebral angiography through the transfemoral (or infrequently radial) route were included. Each patient underwent a brief neurological assessment after the procedure and more detailed assessment was performed if any patient reported occurrence of a headache. The headaches were classified as migraine if the diagnostic criteria specified by International Headache Society were met. The headache severity was classified using a visual numeric rating scale and time to reach pain free status for 2 consecutive hours was ascertained.

RESULTS

Migraine headaches occurred in 5 (3.1%, 95% confidence interval [CI] 1.0-7.2%) of 158 patients who underwent cerebral angiography. The median severity of migraine headaches was 10/10 and time to resolution of headaches was 120 minutes (range 60-360 minutes). Migraine headaches occurred in 4 (18.1%, 95% CI 5.2-40.3%) of 22 patients with a history of migraine and 4 (23.5%, 95% CI 6.8-50%) of 17 patients with regular migraine headaches (≥1 episodes per month). Headaches occurred in 6 (3.8%, 95% CI 1.8-8.0%) patients who did not meet the criteria for migraine headaches.

CONCLUSIONS

We provide occurrence rates of migraine headaches, an under-recognized adverse event, in patients undergoing catheter-based cerebral angiography.

Cerebral catheter angiography and its complications

Catheter-based angiography is an important but invasive procedure in vascular neurology. It is used mainly for diagnosis and for planning treatment in patients with a suspected underlying vascular abnormality. It is often performed as a semiurgent, planned investigation or linked to an interventional procedure. Cerebral angiography provides high-resolution, three-dimensional, pathoanatomical data about the cerebral vasculature and also allows real-time analysis of blood flow. Contrast injections can be repeated to identify subtleties. A physical intervention may also follow angiography. For these reasons, angiography remains the gold standard for delineating vascular lesions of the brain (and spine). Permanent neurological complications are rare, approximately 1%, but become increasingly common in patients aged over 55 years. The main complications are embolic stroke, groin haematoma and contrast-induced nephropathy. In the new era of thrombectomy, it may transpire that other specialists including neurologists may learn to perform the procedure and to manage its complications.

Dual- versus Single-Energy CT-Angiography Imaging for Patients Undergoing Intracranial Aneurysm Repair

BACKGROUND

The invasiveness and risk of thromboembolic complications of catheter angiography underline the need for alternative imaging modalities in patients following intracranial aneurysm (IA) repair. However, the overall image quality of existing noninvasive imaging modalities, such as single-energy CT angiography (SE-CTA), compromises its value in this respect.

OBJECTIVE

We prospectively investigated the value of a novel dual-energy CTA (DE-CTA) scanner and algorithm for assessing the degree of occlusion and parent vessel patency in patients following IA repair.

METHODS

A prospective cohort of 17 patients underwent DE-CTA imaging following surgical or endovascular IA repair. This dataset was matched with an identical historical cohort of 17 patients, who underwent IA repair and SE-CTA imaging. Beam-hardening artifacts, as a measure for objective imaging quality were analyzed based on the volume of a prolate ellipsoid, whereas subjective imaging quality at the IA site and corresponding parent vessels was rated by 2 independent neuroradiologists on a scale from 4 (excellent, no artifacts) to 1 (poor, severe artifacts).

RESULTS

Objective DE-CTA image quality was markedly higher, compared to SE-CTA in patients undergoing surgical (0.77 ± 0.23 vs. 10.91 ± 1.88 mL, respectively; p < 0.001) or endovascular (32.36 ± 10.62 vs. 107.63 ± 24.51 mL, respectively; p = 0.026) IA repair. Subjective image quality for DE-CTA was significantly improved compared to SE-CTA in the surgical group but not in the endovascular group. The calculated dose values for DE-CTA in our study remain markedly below the legally required radiation dose limits.

CONCLUSION

The imaging quality of DE-CTA, especially for patients undergoing surgical IA repair, is distinctly superior, compared to SE-CTA imaging. Therefore, DE-CTA may serve as a noninvasive alternative for assessing the IA occlusion rate and parent vessel patency.

Vascular Imaging: An Unparalleled Decade

Vascular imaging techniques, such as catheter angiography, ultrasound, computed tomography (CT), and magnetic resonance (MR), have all undergone unprecedented innovation and incredible technological leaps in the last 10 years. Ultrasound, CT, and MR have progressed in acquisition speed, resolution, and accuracy to the point that they have now supplanted the former mainstay, invasive catheter-based angiography, despite the advent of digitized angiographic image recording. This review explores the advantages and shortcomings of each technique and how they have changed the diagnosis and assessment of the cardiovascular system for endovascular intervention.

CTA and DSA Evaluation of Patients with Subarachnoid Haemorrhage

We correlate digital subtraction angiography (DSA) and computed tomography with angiographic 3D reconstruction (CTA) in patients with subarachnoid haemorrhage. 45 patients were evaluated with both techniques (CTA and DSA) within 3–4 days after acute haemorrhage: source CT images, MIP and 4D-angio reconstruction and standard DSA were performed and correlated. The MIP tecnique is very easy and quick to perform and operator independent, while 4D-angio reconstruction requires at least 30 minutes to obtain good quality images.

CTA and DSA were equivalent in demonstrating the presence of all 57 aneurysms in the 45 patients. Most aneurysms were located at the level of the circle of Willis; CTA was not adequate to demonstrate the neck of aneurysms in 7 cases located in of the syphon, vertebral artery and posterior communicating artery; CTA gave a good display of the thrombus within the aneurysm.

Patients could go directly from the CT diagnostic room to the operating room in certain types of aneurysm such as those in the anterior communicating artery or middle cerebral artery in which there is a correlation between site of the haemorrhage and the aneurysm. In the future, improvements in MR technology will also exclude aneurysms in sites difficult to evaluate by CTA such as the syphon, so that DSA will be performed only in selected doubtful cases.

Stenosi carotidea: Confronto tra angio-RM e angio-TC spirale

A preliminary study comparing three dimensional time of flight (TOF 3D) Magnetic Resonance angiography (MRA) and spiral CT angiography (SCTA) in the detection and evaluation of internal carotid stenosis.

Digital subtraction angiography (DSA) was the gold standard.

Twenty patients with clinical signs of cerebrovascular insufficiency underwent MRA, SCTA and DSA within a three day period. Both internal carotid arteries were evaluated for absence or degree of stenosis.

Sensitivity, specificity, diagnostic accuracy, concordance, overstimation and understimation were assessed. MRA showed a higher sensitivity, specificity, diagnostic accuracy and concordance compared to SCTA (92% versus 80%, 98,2% versus 96,4%, 96,3% versus 88%, respectively). MRA demonstrated a 5% overstimation rate whereas SCTA demonstrated a 7,5% understimation rate. These differences are not statistically significant.

These results suggest that MRA is the more useful, non invasive modality for the detection and evaluation of the internal carotid artery with a greater than 70% stenoses.

Pediatric MR Angiography of the central nervous system

MRI has now become the initial procedure of investigation for the pediatric patients with stroke. Magnetic resonance angiography (MRA) is an important adjunct in the diagnostic evaluation of these patients who may be affected by vascular abnormalities. During the past year-and-a-half MRA has been utilized with an increasing frequency and has replaced in many cases the need for conventional angiography. The clinical management of the young patients can be planned on the basis of MRA, that can be performed as an intrinsic part of the initial MRI study. At present, the diagnostic accuracy of MRA is sufficient that conventional angiography can be circumvente or performed at a time when the patients clinical conditions have stabilized and just prior to the operative procedures, if surgery is requested.

Extracranial and Transcranial Color-Coded Sonography Reduce the Need for Angiography Prior to Carotid Endarterectomy

The growing need for carotid endarterectomy must be accompanied by safe and reliable methods of imaging the cerebral circulation. The authors used extracranial and tran scranial color-coded sonography to evaluate the cervical carotid arteries and the basal cerebral circulation in 76 patients prior to surgery, aiming to reduce the need for preop erative angiography. In 3 patients (proximal and distal carotid disease; subtotal occlusion) carotid ultrasound failed to define the nature and extent of stenosis adequately, and thus conventional angiography was performed. Transcranial imaging identified intracranial stenotic disease in 4 patients and interhemispheric collateral flow in 29 patients. All patients underwent carotid endarterectomy without any complications due to inadequate preoperative imaging. An ultrasound-based approach eliminated the need for angiography in the majority of patients with significant implications for risk reduction and financial expenditure.

Duplex Ultrasonography to Predict Internal Carotid Artery Stenoses Exceeding 50% and 70% as Defined by NASCET: The Need for Multiple Criteria

Carotid duplex scanning is being used more frequently as the sole preoperative diagnostic imaging modality for patients considered candidates for carotid endarterectomy. The North American Symptomatic Carotid Endarterectomy Trial (NASCET) has demonstrated the benefit of surgical treatment in patients with carotid stenoses exceeding 70%. The purpose of this study was to determine duplex criteria that accurately predict carotid stenoses exceeding 50% and 70% as defined by NASCET arteriographic criteria. One hundred forty-one patients (264 carotid arteries) considered surgical candidates were prospectively studied over a 2-year period by use of both duplex scanning and digital subtraction cerebral arteriography. Carotid artery stenosis was determined by a single radiologist using NASCET arteriographic criteria. Peak systolic velocity (PSV) and enddiastolic velocity (EDV) were measured in the internal carotid (ICA) and common carotid (CCA) arteries by use of duplex scanning. ICA/CCA velocity ratios were calculated for PSV and EDV. Sensitivity, specificity, positive and negative predictive values, and accuracy were calculated. PSVICA/CCA provided the highest sensitivity, and EDVICA the highest specificity in this study. Arteriographic stenoses exceeding 50% and 70% were reliably predicted with use of these duplex criteria. It is concluded that duplex criteria can predict carotid stenoses exceeding 50% and 70% as defined by NASCET arteriographic criteria. These criteria should be independently validated by other vascular laboratories.

Clinical Benefit of Carotid Endarterectomy Based on Duplex Ultrasonography

Carotid endarterectomy has been shown to significantly reduce the risk of stroke caused by carotid artery stenosis in selected patients. Limiting the morbidity and costs of this process without increasing the risks should further improve the benefits of this procedure. Results were prospectively collected from 123 consecutive carotid endarterectomies performed at a community teaching hospital. All patients underwent duplex ultrasonography for preoperative evaluation. Catheter angiography was used on a selective basis. Preferential use of regional anesthetic and selective use of the intensive care unit were applied. The mortality, morbidity, complications, and costs were then compared for the group receiving only preoperative duplex ultrasonography with those undergoing catheter angiography preoperatively. Age, comorbid risk factors, indications for carotid endarterectomy, and incidence of stroke were similar in both patient groups. The rates of mortality, morbidity, and stroke for carotid endarterectomy were low (mortality 0%, morbidity 6.5%, stroke 0.8%). For preoperative evaluation all patients underwent duplex ultrasonography (100%) and 28 (23%) underwent preoperative catheter angiography in addition to duplex ultrasonography. The complication rate associated with catheter angiography was 6/28 (21%). Complications included groin hematoma (7%), pseudoaneurysm (3.6%), bradycardia (7%), and unstable angina (3.6%). Costs for duplex ultrasonography averaged $165 and additional costs incurred by the use of catheter angiography averaged $4,200. Intraoperative assessment of the carotid endarterectomy site did not change based on the use of preoperative catheter angiography. Morbidity, mortality, and stroke rates were the same for the 2 groups. The preoperative use of duplex ultrasonography for the sole evaluation in carotid endarterectomy is well established. The use of preoperative catheter angiography is still preferred by a subset of surgeons. The use of catheter angiography is associated with significant morbidity and additional costs when compared to performing carotid endarterectomy based solely on preoperative duplex ultrasonography. The added costs and morbidity of angiography increase the societal cost of this procedure without significant clinical improvement in patient outcome.

CBCT-based 3D MRA and angiographic image fusion and MRA image navigation for neuro interventions

Digital subtracted angiography (DSA) remains the gold standard for diagnosis of cerebral vascular diseases and provides intraprocedural guidance. This practice involves extensive usage of x-ray and iodinated contrast medium, which can induce side effects. In this study, we examined the accuracy of 3-dimensional (3D) registration of magnetic resonance angiography (MRA) and DSA imaging for cerebral vessels, and tested the feasibility of using preprocedural MRA for real-time guidance during endovascular procedures.Twenty-three patients with suspected intracranial arterial lesions were enrolled. The contrast medium-enhanced 3D DSA of target vessels were acquired in 19 patients during endovascular procedures, and the images were registered with preprocedural MRA for fusion accuracy evaluation. Low-dose noncontrasted 3D angiography of the skull was performed in the other 4 patients, and registered with the MRA. The MRA was overlaid afterwards with 2D live fluoroscopy to guide endovascular procedures.The 3D registration of the MRA and angiography demonstrated a high accuracy for vessel lesion visualization in all 19 patients examined. Moreover, MRA of the intracranial vessels, registered to the noncontrasted 3D angiography in the 4 patients, provided real-time 3D roadmap to successfully guide the endovascular procedures. Radiation dose to patients and contrast medium usage were shown to be significantly reduced.Three-dimensional MRA and angiography fusion can accurately generate cerebral vasculature images to guide endovascular procedures. The use of the fusion technology could enhance clinical workflow while minimizing contrast medium usage and radiation dose, and hence lowering procedure risks and increasing treatment safety.

Percutaneous Stenting of the Internal Carotid Artery: The European CAST I Study

Purpose:

To report the results of a multicenter safety trial of percutaneous carotid stenting performed by vascular surgeons.

Methods:

Symptomatic or asymptomatic patients ≥ 65 years of age with internal carotid artery (ICA) stenoses ≥ 70% and ≤ 2-cm long were eligible for enrollment. The procedures were performed in an operating room with the choice of anesthesia and the percutaneous access site at the discretion of the surgeon. Only Palmaz stents were used.

Results:

From January 1, 1996 to December 31, 1997, 99 patients (74 men, mean age 70 years, range 51 to 94) were enrolled in the study. More than half (57 of 99 patients) were asymptomatic. The direct cervical approach was used predominantly (97%). Three (3%) cases were converted to surgery for inability to access the artery or deploy the stent (technical success 97%). No perioperative death or myocardial infarction was reported. Six (6%) procedural complications included 1 reversible arterial spasm, 2 dissections, 1 cervical hematoma, and 2 residual stenoses. One neurological event reversed within 7 days(1% minor stroke rate) and 4 (4%) transient ischemic attacks resolved within 24 hours. One (1%) asymptomatic early occlusion occurred 2 days postoperatively. No neurological event was observed in the 1- to 24-month follow-up (mean 13 months). Two (2%) patients died of nonprocedurally related causes. No stent compression was seen, but 1 asymptomatic occlusion and 3 asymptomatic, non-flow-limiting restenoses (2 < 40%, 1 at 60%) were found within 1 year (3% restenosis rate on an intention-to-treat basis). Patency was 98% at 1 year.

Conclusions:

The results of this trial support the contention that carotid stenting of short ICA lesions can be performed with a low neurological complication rate.

Carotid Artery Imaging in the United Kingdom: A Postal Questionnaire of Current Practice

There has been a steady rise in the use of carotid duplex imaging in the selection of patients for carotid endarterectomy (CEA). Some would suggest that CEA could be safely performed without preoperative contrast angiography. The purpose of this study was to focus on the role of duplex imaging among vascular surgeons in the United Kingdom and to highlight current practices in imaging prior to CEA. A postal questionnaire was sent to all consultant members of the Vascular Surgical Society of Great Britain and Ireland about the choice of imaging prior to selection of patients for CEA, preoperative imaging, and choice of imaging (if any) in the confirmation of carotid occlusion indicated by duplex scanning. Of 396 questionnaires sent, 323 (82%) were returned. Of these, 259 (80%) consultants performed carotid surgery, 118 (45%) in university hospitals (UHs) and 141 (53%) in district general hospitals (DGHs). One hundred eighteen (100%) and 137 (97%) respondents, respectively, chose duplex scanning as their first-line investigation. Sixty (51%) respondents in UHs and 49 (35%) respondents in DGHs repeated duplex scanning immediately preoperatively, with 57 (95%) and 46 (94%), respectively, using duplex scanning. Forty-seven (40%) respondents in UHs and 78 (55%) respondents in DGHs would reconfirm an occlusion, with 30 (64%) and 48 (62%), respectively, using computed tomography and magnetic resonance imaging as their preferred tool. Our study shows that duplex scanning is the first-line imaging technique for patient selection for CEA by vascular surgeons in the United Kingdom. Magnetic resonance imaging and computed tomography are replacing conventional angiography where duplex scanning is equivocal.

Three-dimensional image fusion of CTA and angiography for real-time guidance during neurointerventional procedures

AIM

To evaluate the accuracy of three-dimensional (3D) images from two modalities-CT angiography (CTA) and digital subtraction angiography (DSA). Additionally, to explore the value of using preprocedural CTA for real-time guidance during neurointerventional procedures.

MATERIALS AND METHODS

25 patients with CTA-confirmed cerebral arterial lesions were enrolled. For 12 of these patients, 3D DSA images of the contrast medium-enhanced target vessel were acquired during the intervention and registered with the preprocedurally acquired CTA images for evaluation of the accuracy of image fusion, focusing on the target vessel and the lesion. For the other 13 patients, a low-dose non-contrast 3D angiographic scan was performed. The preprocedurally acquired CTA image was then registered with the coordinate of angiography and overlaid onto the live fluoroscopic image to provide interventional guidance.

RESULTS

Based on visual inspection by two experienced physicians and quantitative evaluation, excellent accuracy in the 3D registration of the CTA and DSA was achieved for all 12 patients examined. Additionally, CTA could be used successfully to guide the interventional procedures, including both diagnostic DSA and stent treatment. The radiation dose and contrast medium use were compared with those used by conventional interventional procedures and both were found to be significantly reduced.

CONCLUSIONS

3D CTA and angiographic image fusion was approved as highly accurate for neurovasculature. Additionally, using the fusion technique to guide interventional procedures enhanced the workflow, and required much less radiation exposure and contrast medium use, thus helping to reduce potential risks and increase treatment safety.

Acoustic shadowing impairs accurate characterization of stenosis in carotid ultrasound examinations

OBJECTIVE

Duplex ultrasonography (DUS) has been the mainstay for diagnosing carotid artery stenosis and is often the sole diagnostic modality used prior to intervention. Highly calcified plaque, however, results in an acoustic shadow (AcS) that obscures the vessel lumen and inhibits the sonographer's ability to obtain Doppler velocity measurements. It is unknown whether DUS can accurately determine the degree of carotid stenosis in these settings.

METHODS

From July 2012 to December 2013, all patients with AcS on DUS measuring ≥5 mm in the longitudinal axis were cross-referenced with multidetector computed tomographic angiography (MD-CTA) images of the neck to define the study population. After standardizing the MD-CTA windows, percent stenosis was determined by cross-sectional area reduction using two separate previously described methods based on North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) criteria. DUS waveform parameters in the internal carotid artery near the AcS were then compared with these MD-CTA measurements to determine the accuracy of DUS in characterizing the severity of carotid stenosis.

RESULTS

During this period, 8517 DUS studies were performed at the Massachusetts General Hospital, 550 of which had AcS, for an incidence of 6.45%. There were 92 lesions with a concomitant MD-CTA; however, seven were excluded because of poor study quality, because ≥6 months had elapsed between DUS and MD-CTA, or because the patient had undergone carotid reconstruction between studies. Of the 85 remaining lesions, DUS characterized 17 as severe (peak systolic velocity [PSV] >250 cm/s), 31 as moderate (PSV = 151-250 cm/s), and 37 as mild (PSV ≤150 cm/s) stenoses using PSV criteria. PSV weakly correlated with CTA-NASCET (r = 0.361; P = .004) and CTA-ECST (r = 0.306; P = .004) percent stenosis. Using PSV >250 cm/s as the predictor of >70% stenosis, and a ≥70% cutoff by both CTA-ECST and CTA-NASCET methods as the reference measure, DUS sensitivity ranged from 22.7% to 32.5%, specificity from 89.4% to 91.1%, positive predictive value from 88.2% to 76.4%, and negative predictive value from 25% to 60.2%. A subgroup analysis of lesions identified as non-severe by DUS revealed that waveforms with lower deceleration were associated with severe stenosis on CTA.

CONCLUSIONS

In the presence of AcS, DUS alone is inadequate to accurately determine the degree of carotid stenosis with sensitivity, specificity, and negative predictive values far below that needed for clinical decision-making. MD-CTA may be necessary for improved characterization of plaque in these AcS lesions. Further studies are needed to determine DUS parameters that may identify patients who should undergo further evaluation with MD-CTA to characterize the true severity of the stenosis.

Preoperative Computed Tomography Angiography for Evaluation of Feasibility of Free Flaps in Difficult Reconstruction of Head and Neck

BACKGROUND

Free tissue transfer has been advocated for anatomic and functional reconstruction of soft tissue defects after surgical removal of an extensive recurrent tumor and/or arising from previous irradiation in the head and neck. We report a case series of difficult reconstruction in the head and neck in which preoperative computed tomography (CT) angiography was utilized to evaluate the feasibility of free flap reconstruction. The preoperative radiological evaluation was performed to determine the availability of reliable vessels for anastomosis in free flap reconstruction. If none was found, regional pedicle flap or palliative treatment was applied instead. The use of CT angiography allows the clinical surgeon to perform precise surgical planning with greater confidence. This may improve surgical results, thereby potentially reducing perioperative morbidity.

METHODS

Twenty CT angiograms were obtained from 20 patients. All patients were men with a mean age of 57.2 years (range, 42-72 years) and were scheduled to undergo difficult reconstruction in the head and neck. All patients (20/20 [100%]) suffered from oral squamous cell carcinoma. They had all received extensive operations and radiation therapy. Eighteen patients (18/20 [90%]) had completed a course of perioperative irradiation. The CT angiography reports were used to perform detailed preoperative surgical planning accordingly. The findings of CT angiography were classified into 3 groups: group I: normal CT angiography (patent recipient arteries) (Fig. 3); group II: abnormal CT angiography (recipient vessels were present but stenosis or atherosclerotic lesions were noted) (Fig. 4); group III: abnormal CT angiography with no patent recipient arteries in bilateral sides of the neck (Fig. 5); CT angiography results were correlated to the operative findings.

RESULTS

The patients were classified into 3 groups based on the angiographic findings. Six patients (6/20 [30%]) were assigned to group I, 8 patients (8/20 [40%]) to group II, and 6 patients (6/20 [30%]) to group III. In groups I and III, all patients (12/12 [100%]) underwent the treatment according to the original preoperative detailed planning. No flap failure was noted in these 2 groups. In group II, 4 patients' recipient vessels (4/8 [50%]) possessed adequate blood flow intraoperatively; hence, microvascular free flaps were transplanted. Venous congestion in 1 case (1/4 [25%]) was noted. The remaining patients in this group (4/8 [50%]) underwent reconstruction with pedicle flaps rather than free flaps because of the lack of suitable target vessels intraoperatively. All flaps (4/4 [100%]) survived. Among the patients who were treated surgically, intraoperative findings were in accordance with those predicted by CT angiography. The total abnormality rate of CT angiography was 70%. Vascular abnormalities detected as a result of preoperative CT angiography led to changes in the operative plan in 50% (10/20) of the patients.

CONCLUSIONS

The use of CT angiography should be considered for difficult microsurgical reconstructions in the head and neck. When an abnormality in vascular anatomy is detected by CT angiography, the surgeon is advised to consider altering the operative plan accordingly. This allows precise operation, thereby maximizing the possibility of an optimal outcome. Changing the operative plan based on results of CT angiography may also help to avoid the difficult situation in which the surgeon finds that there are no suitable recipient vessels for free flap reconstruction during the operation. In addition, CT angiography enables surgeons to conduct the preoperative surgical planning with greater confidence, thereby potentially enhancing the success rate of difficult reconstructions in the head and neck, which in turn would tend to improve the perioperative course for the patient and consequently to improve results by decreasing vascular complication rates.