Suitable methods of measuring acceleration time in the diagnosis of internal carotid artery stenosis

Usefulness of "AcT ratio" in diagnosis of internal carotid artery stenosis: a multicenter, retrospective, observational study

PURPOSE

The ratio of the internal carotid artery (ICA) to the common carotid artery (CCA), especially the "AcT ratio," which is a modified measurement method of acceleration time, is useful for diagnosing ICA-origin stenosis. However, previous studies were single-center studies. Therefore, this multicenter, retrospective, cross-sectional study aimed to determine whether a method using the AcT ratio is useful for estimating stenosis rates.

METHODS

This study included 461 vessels subjected to carotid artery ultrasonography and evaluation for ICA-origin stenosis via NASCET at four hospitals. The duration from the steep rise point to the inflection point or the first peak was defined as AcT on pulsed wave Doppler. The AcT ratio was calculated as AcT of ICA/AcT of ipsilateral CCA. The AcT ratio and rate of ICA-origin stenosis were analyzed using Pearson's correlation coefficient, simple regression analysis, and ROC curve.

RESULTS

A significant positive correlation was observed between the AcT ratio and NASCET stenosis. NASCET stenosis of ≥ 50% had a sensitivity, specificity, and negative predictive value (NPV) of 70.2%, 71.6%, and 91.5%, respectively, when the cut-off value of the AcT ratio was 1.17. NASCET stenosis of ≥ 70% had a sensitivity, specificity, and NPV of 70.5%, 72.1%, and 95.9%, respectively, when the cut-off value of the AcT ratio was 1.22.

CONCLUSIONS

The findings of this multicenter, retrospective, cross-sectional study suggest that the AcT ratio is useful for diagnosing ICA-origin stenosis, especially for diagnosis by exclusion. NASCET stenosis of ≥ 50% was considered unlikely if the Act ratio was ≤ 1.17, whereas NASCET stenosis of ≥ 70% was considered unlikely if it was ≤ 1.22.

Arterial Blood-Flow Acceleration Time on Doppler Ultrasound Waveforms: What Are We Talking About?

In recent years, the assessment of systolic acceleration in lower-extremity peripheral artery disease (PAD) has been brought back into the spotlight, whatever measure is used: time (in s) or acceleration (in cm.s^-2). Acceleration time (also called systolic rise time) and maximal acceleration are two different but very useful measurements of growing interest in PAD. A background of the historical development, physics rationale, semantics, and methods of measurement, as well as their strengths and weaknesses, are discussed herein. Acceleration time is a powerful tool for predicting significant arterial stenosis or for estimating the overall impact of PAD as it is highly correlated to the ankle or toe pressure indexes. It could even become a new diagnostic criterion for critical limb ischemia. Similarly, maximal systolic acceleration ratios are highly predictive of carotid or renal stenosis. However, the literature lacks reference standards or guidelines for the assessment of such variables, and their measurement techniques seem to differ between authors. We propose herein a semantic and measurement statement order to clarify and help standardize future research.

Usefulness of carotid duplex ultrasonography in predicting residual large-vessel occlusions after intravenous recombinant tissue plasminogen activator therapy in patients with acute ischemic stroke

PURPOSE

Endovascular therapy (EVT) preceded by intravenous thrombolysis with recombinant tissue plasminogen activator (iv-rtPA) has been established as a standard treatment in patients with stroke caused by large-vessel occlusion (LVO). Primary stroke centers without EVT competence need to identify patients with residual LVO after iv-rtPA therapy and transport them to an EVT-capable facility. Carotid ultrasonography (CUS) is easily applicable at bed side and useful for detecting extra- and intracranial LVO. This study aimed to determine whether CUS findings at admission are useful to predict patients with residual LVO after iv-rtPA.

METHODS

Patients scheduled to undergo iv-rtPA for acute cerebral infarction were registered. Before iv-rtPA, they underwent CUS, followed by CTA or MRA evaluation within 6 h after iv-rtPA. A model that can achieve 100% sensitivity for detecting residual LVO after iv-rtPA was studied.

RESULTS

This study included 68 of 116 patients treated with iv-rtPA during the study period. National Institutes of Health Stroke Scale (NIHSS) score (cutoff value = 10) on arrival, hyperdense MCA sign on non-contrast CT, end-diastolic (ED) ratio on CUS, and eye deviation were significantly different between patients with residual LVO after iv-rtPA and those without. If any of these clinical features are positive in the screening test, residual LVO could be predicted with 100% sensitivity, 50% specificity, 64% positive predictive value, and 100% negative predictive value.

CONCLUSION

Prediction of residual LVO with 100% sensitivity may be feasible by adding CUS to NIHSS score > 10, the presence of eye deviation, and hyperdense MCA sign.

Ultrasound diagnosis of carotid artery stenosis and occlusion

Carotid artery ultrasonography is capable of diagnosing or inferring the presence or absence of stenosis or occlusion of the internal carotid artery (ICA) and vertebral artery (VA), as well as the not directly observable distal ICA, middle cerebral artery (MCA), and basilar artery (BA). Stenosis at the origin of the ICA is mainly evaluated using the parameter peak systolic velocity (PSV), with values of ≥ 200-230 cm/s indicating severe stenosis. Recently, the acceleration time ratio has been reported for diagnosis of ICA origin stenosis. An indicator called the end-diastolic (ED) ratio can be used for diagnosing occlusion of the distal ICA or the M1 segment of the MCA. The PSV of stenosis can be used to diagnose stenosis at the beginning of the VA or V1, and mean flow velocity, mean ratio, and diameter ratio can be used to diagnose distal VA occlusion. Furthermore, the usefulness of the VA pulsatility index and resistance index has been suggested for diagnosing stenosis or occlusion of the BA. This review outlines diagnostic sonography criteria for stenosis and occlusion of extracranial and intracranial arteries.

Risk Factors and Distribution Characteristics of Intracranial and Intracranial Artery Stenosis in Young Sufferers with Ischemic Stroke

In order to explore the risk factors of intracranial and intracranial arterial stenosis, the distribution of young ischemic stroke sufferers with intracranial and intracranial arterial stenosis and the related are analyzed. In this study, a total of 213 young sufferers with ischemic stroke (IS) admitted to our hospital from February 2019 to September 2021 are selected. According to the CT diagnosis of intracranial artery stenosis (AS), 213 patients are divided into two groups, with 86 in the AS Group and 127 in the non-AS Group. To analyze the distribution of intracranial and intracranial AS in young patients with ischemic stroke, 86 patients with AS are examined by carotid B-mode ultrasound. Furthermore, a univariate analysis is performed on the relevant indicators of the sufferers in the cancer (CA) set and the two sets without CA, and then, the indicators with statistically extensive disparity were selected for multivariate logistic regression analysis of the risk factors for CA symptoms. The results show 50% of the sufferers with moderate or severe ischemic CA in young adults and 63.95% of the sufferers with intracranial artery stenosis. It is clearly evident that the main risk factors affecting the occurrence of intracranial and intracranial arteries in young IS are hypertension and long-term smoking, long-term drinking, and hyperlipidemia.

Point-of-care ultrasound for stroke patients in the emergency room

Stroke requires rapid determination of the cause to provide timely and appropriate initial management. Various ultrasonographic techniques have been evaluated as ways to determine the cause of stroke; among them, carotid artery ultrasonography is particularly useful since it provides considerable information within a short time period when used to evaluate a specific site. In the emergency room, carotid artery ultrasonography can be used to diagnose internal carotid artery stenosis, predict an occluded vessel, and infer the cause of ischemic stroke. Additionally, carotid artery ultrasonography can diagnose different conditions including subclavian artery steal syndrome, bow hunter's stroke, Takayasu's arteritis, moyamoya disease, and dural arteriovenous fistula. Furthermore, patients with ischemic stroke with a pulse deficit or hypotension must be differentiated from acute type A aortic dissection, which requires emergency surgery; carotid artery ultrasonography can immediately differentiate between the two conditions by identifying the intimal flap of the common carotid artery. The following article provides an overview of carotid artery ultrasonography performed as point-of-care ultrasound in the emergency room in patients with suspected stroke.