Finding the optimal deconvolution algorithm for MR perfusion in carotid stenosis: Correlations with angiographic cerebral circulation time

Comparison of Effects of Propofol and Sevoflurane on the Cerebral Vasculature Assessed by Digital Subtraction Angiographic Parameters in Patients Treated for Ruptured Cerebral Aneurysm: A Preliminary Study

BACKGROUND

Studies have evaluated the effects of volatile and intravenous anesthetic agents on the cerebral vasculature with inconsistent results. We used digital subtraction angiography to compare the effects of propofol and sevoflurane on the luminal diameter of cerebral vessels and on cerebral transit time in patients with aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

This prospective preliminary study included adult patients with good-grade aSAH scheduled for endovascular coil embolization; patients were randomized to receive propofol or sevoflurane anesthesia during endovascular coiling. The primary outcome was the luminal diameter of 7 cerebral vessel segments measured on the diseased and nondiseased sides of the brain at 3 time points: awake, postinduction of anesthesia, and postcoiling. Cerebral transit time was also measured as a surrogate for cerebral blood flow.

RESULTS

Eighteen patients were included in the analysis (9 per group). Baseline and intraoperative parameters were similar between the groups. Propofol increased the diameter of 1 vessel segment at postinduction and postcoiling on the diseased side and in 1 segment at postcoiling on the nondiseased side of the brain ( P <0.05). Sevoflurane increased vessel diameter in 3 segments at postinduction and in 2 segments at postcoiling on the diseased side, and in 4 segments at postcoiling on the nondiseased side ( P <0.05). Cerebral transit time did not change compared with baseline awake state in either group and was not different between the groups.

CONCLUSIONS

Sevoflurane has cerebral vasodilating properties compared with propofol in patients with good-grade aSAH. However, sevoflurane affects cerebral transit time comparably to propofol.

Peri-therapeutic multi-modal hemodynamic assessment and detection of predictors for symptomatic in-stent restenosis after percutaneous transluminal angioplasty and stenting

Backgrounds

This study performed multi-modal hemodynamic analysis including quantitative color-coded digital subtraction angiography (QDSA) and computational fluid dynamics (CFD) to delineate peri-therapeutic hemodynamic changes and explore the risk factors for in-stent restenosis (ISR) and symptomatic ISR (sISR).

Methods

Forty patients were retrospectively reviewed. Time to peak (TTP), full width at half maximum (FWHM), cerebral circulation time (CCT), angiographic mean transit time (aMTT), arterial stenosis index (ASI), wash-in gradient (WI), wash-out gradient (WO) and stasis index were calculated with QDSA and translesional pressure ratio (PR) and wall shear stress ratio (WSSR) were quantified from CFD analysis. These hemodynamic parameters were compared between before and after stent deployment and multivariate logistic regression model was established to detect predictors for ISR and sISR at follow-up.

Results

It was found that stenting generally reduced TTP, stasis index, CCT, aMTT and translesional WSSR while significantly increased translesional PR. ASI decreased after stenting, and during the mean follow-up time of 6.48 ± 2.86 months, lower ASI (<0.636) as well as larger stasis index were corroborated to be independently associated with sISR. aMTT showed a linear correlation with CCT before and after stenting.

Conclusion

PTAS not only improved cerebral circulation and blood flow perfusion but also changed local hemodynamics significantly. ASI and stasis index derived from QDSA were proved to play a prominent role in risk stratification for sISR. Multi-modal hemodynamic analysis could facilitate intraoperative real-time hemodynamic monitoring and help the determination of the end point of intervention.

Cerebral Circulation Time Is a Potential Predictor of Disabling Ischemic Cerebrovascular Events in Patients With Non-disabling Middle Cerebral Artery Stenosis

Patients with non-disabling middle cerebral artery (MCA) stenosis (ND-MCAS) are at risk for disabling ischemic cerebrovascular events (DICE) despite aggressive medical therapy. In this study, we aimed to verify whether cerebral circulation time (CCT) was a potential predictor of DICE in patients with ND-MCAS. From January 2015 to January 2020, 46 patients with ND-MCAS treated with aggressive medical therapy were enrolled for digital subtraction angiography (DSA) in this convenience sampling study. They were divided into the DICE (-) and DICE (+) groups based on the occurrence of DICE within 3 months after DSA. The CCT was defined as the time from the appearance of the MCA to the peak intensity of the Trolard vein during DSA. The rCCT (relative CCT) was defined as the ratio of the CCT of the stenotic side (sCCT) to the CCT of the healthy side (hCCT). The differences in sCCT, hCCT, and rCCT between the two groups were analyzed with Mann-Whitney U tests. Logistic regression analysis was performed to evaluate the association between the risk factors and DICE. Receiver operating characteristic (ROC) curves were constructed to assess the predictive value of rCCT in identifying DICE in ND-MCAS patients. The results showed that DICE appeared in 5 of the 46 patients within 3 months. rCCT were significantly increased in the DICE (+) group compared with the DICE (-) group [1.08 (1.05, 1.14) vs. 1.30 (1.22, 1.54), p < 0.001]. Logistic regression analysis found that prolonged rCCT was an independent positive prognostic factor for DICE (odds ratio = 1.273, p = 0.019) after adjustment for potential confounders (age, diabetes, antithrombotic use, and stenosis degree). ROC analysis showed that rCCT provided satisfactory accuracy in distinguishing the DICE (+) group from the DICE (-) group among ND-MCAS patients (area under the curve = 0.985, p < 0.001), with an optimal cutoff point of 1.20 (100% sensitivity, 97.6% specificity). In conclusion, prolonged rCCT is independently associated with the occurrence of DICE in ND-MCAS patients and may be used to identify individuals at risk of DICE.

Chronic occlusion of the internal carotid artery: Endovascular revascularization technique of long occlusive lesions

BACKGROUND

Despite series of endovascular recanalization of chronically occluded ICA (COICA) have been already reported, technical aspects of this strategy were not described. We discussed technical details and feasibility of this strategy.

CLINICAL PRESENTATION

Five COICA (C1-cavernous ICA) patients presenting symptomatic hypoperfusion were recanalized with multiple coronary and carotid stents. All patients experienced long-term reperfusion with resolution of the clinical symptoms.

CONCLUSION

Endovascular revascularization of COICA appears feasible and associated with improvement of the hypoperfusion.

Effects of propofol versus sevoflurane on cerebral circulation time in patients undergoing coiling for cerebral artery aneurysm: a prospective randomized crossover study

Many neuroendovascular treatments are supported by real-time anatomical and visual hemodynamic assessments through digital subtraction angiography (DSA). Here we used DSA in a single-center prospective randomized crossover study to assess the intracranial hemodynamics of patients undergoing coiling for cerebral aneurysm (n = 15) during sevoflurane- and propofol-based anesthesia. Color-coded DSA was used to define time to peak density of contrast medium (TTP) at several intravascular regions of interest (ROIs). Travel time at a particular ROI was defined as the TTP at the selected ROI minus TTP at baseline position on the internal carotid artery (ICA). Travel time at the jugular bulb on the anterior-posterior view was defined as the cerebral circulation time (CCT), which was divided into four segmental circulation times: ICA, middle cerebral artery (MCA), microvessel, and sinus. When bispectral index values were kept between 40 and 60, CCT (median [interquartile range]) was 10.91 (9.65-11.98) s under propofol-based anesthesia compared with 8.78 (8.32-9.45) s under sevoflurane-based anesthesia (P < 0.001). Circulation times for the ICA, MCA, and microvessel segments were longer under propofol-based anesthesia than under sevoflurane-based anesthesia (P < 0.05 for all). Our results suggest that, relative to sevoflurane, propofol decreases overall cerebral perfusion.

Automatic flow analysis of digital subtraction angiography using independent component analysis in patients with carotid stenosis

PURPOSE

Current time-density curve analysis of digital subtraction angiography (DSA) provides intravascular flow information but requires manual vasculature selection. We developed an angiographic marker that represents cerebral perfusion by using automatic independent component analysis.

MATERIALS AND METHODS

We retrospectively analyzed the data of 44 patients with unilateral carotid stenosis higher than 70% according to North American Symptomatic Carotid Endarterectomy Trial criteria. For all patients, magnetic resonance perfusion (MRP) was performed one day before DSA. Fixed contrast injection protocols and DSA acquisition parameters were used before stenting. The cerebral circulation time (CCT) was defined as the difference in the time to peak between the parietal vein and cavernous internal carotid artery in a lateral angiogram. Both anterior-posterior and lateral DSA views were processed using independent component analysis, and the capillary angiogram was extracted automatically. The full width at half maximum of the time-density curve in the capillary phase in the anterior-posterior and lateral DSA views was defined as the angiographic mean transient time (aMTT; i.e., aMTTAP and aMTTLat). The correlations between the degree of stenosis, CCT, aMTTAP and aMTTLat, and MRP parameters were evaluated.

RESULTS

The degree of stenosis showed no correlation with CCT, aMTTAP, aMTTLat, or any MRP parameter. CCT showed a strong correlation with aMTTAP (r = 0.67) and aMTTLat (r = 0.72). Among the MRP parameters, CCT showed only a moderate correlation with MTT (r = 0.67) and Tmax (r = 0.40). aMTTAP showed a moderate correlation with Tmax (r = 0.42) and a strong correlation with MTT (r = 0.77). aMTTLat also showed similar correlations with Tmax (r = 0.59) and MTT (r = 0.73).

CONCLUSION

Apart from vascular anatomy, aMTT estimates brain parenchyma hemodynamics from DSA and is concordant with MRP. This process is completely automatic and provides immediate measurement of quantitative peritherapeutic brain parenchyma changes during stenting.

Prolonged cerebral circulation time is more associated with symptomatic carotid stenosis than stenosis degree or collateral circulation

BACKGROUND AND PURPOSE

Current practice of revascularization for carotid stenosis (CS) primarily relies on symptoms and degree of stenosis. Other parameters, such as collateral circulation and cerebral circulation time (CCT), might influence the stroke risk in CS. This study was conducted to (1) investigate whether CCT is more associated with symptomatic CS than degree of stenosis and (2) elucidate the associations among the degree of stenosis, collateral status, and CCT.

METHODS

From 2010 to 2016, 82 patients with unilateral CS were enrolled for DSA and divided into symptomatic and asymptomatic groups based on clinical presentation. CCT was defined as the difference between the time taken by the cavernous internal carotid artery and parietal vein to reach the maximal contrast medium intensities on lateral DSA. The degree of stenosis, collateral status, and CCT of the two groups were compared. Logistic regression analysis was performed to estimate the OR for symptomatic CS with the imaging variables.

RESULTS

The symptomatic group had a significantly higher degree of stenosis and longer CCT. CCT (OR 1.95, p=0.013) was more associated with symptomatic CS than the degree of stenosis (OR 1.03, p=0.229), after adjustment for potential confounders-namely, age, sex, antithrombotic use, and collateral status. Symptomatic high grade CS with collaterals had a non-significantly shorter CCT than those without collaterals.

CONCLUSIONS

DSA derived CCT is more reflective of the hemodynamic differences between symptomatic and asymptomatic CS than degree of stenosis. Collaterals may not effectively reduce CCT in symptomatic high grade CS.