Angiographic circulation time and cerebral blood flow during balloon test occlusion of the internal carotid artery

Endovascular Treatment of Wide-Neck Bifurcation Aneurysm: Recent Trends in Coil Embolization with Adjunctive Technique

Wide-neck bifurcation aneurysms (WNBAs) are sometimes challenging to treat. During endovascular treatment, it is important to prevent coil deviation and preserve normal vessels. Adjunctive balloon- and stent-assisted techniques have been developed. A meta-analysis of endovascular treatments of WNBAs revealed that only 40% of patients had complete occlusion. Recently, novel devices have been developed to expand the range of treatment options. Flow-diverter stents and intra-aneurysmal flow disruption devices do not require coils; however, coil embolization remains the standard procedure used by many neurointerventionists. This review describes the recent trends in adjunctive techniques for supporting coil embolization for WNBAs. We referred to literature on balloon-assisted techniques, stent-assisted techniques, Y-stenting, PulseRider, Barrel stents, Comaneci temporary stents, pCONUS, and eCLIPs. These reports showed that adequate embolization rates were generally greater than 80%, and the complete occlusion rate was as high as 94.6%. All devices had a relatively high occlusion rate; however, it may be inaccurate to simply compare each device because of the heterogeneity of the studies. It is important to select the best treatment for each individual case by considering not only literature-based efficacy and safety but also patient background, aneurysm characteristics, and operator experience.

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.

Association between collaterals, cerebral circulation time and outcome after thrombectomy of stroke

OBJECTIVE

Cerebral circulation time (CCT) and collateral score (CS) are associated with functional outcomes in acute ischemic stroke (AIS) patients after endovascular treatment (EVT), and may be related to each other. We aim to determine the relationship between CS and CCT on functional outcomes.

METHODS

We retrospectively enrolled consecutive patients with anterior circulation large vessel occlusion (LVO) AIS who received EVT. CS and CCT were measured based on digital subtraction angiography (DSA). We defined CS 0-2 and 3-4 as poor and good collateral status, respectively, and used change of CCT (cCCT), which was defined as the change of stroke side CCT (sCCT) versus healthy side CCT (hCCT). Mediating analysis was used to evaluate the influence of cCCT on the association between CS and functional outcomes, and ROC curves were further used to explore the predictive ability of the interaction between cCCT and CS for functional outcomes.

RESULTS

A total of 100 patients were enrolled in the final analysis. A higher cCCT (r = -0.239; p = 0.017) was associated with lower CS, and cCCT mediated the association of CS with functional outcome. Logistic regression analysis found that CS, cCCT and cCCT-CS interactions were independently associated with functional outcome, and cCCT-CS interaction has better predictive performance, with a higher area under curve value than CS or cCCT alone (0.79 vs. 0.75 or 0.75).

INTERPRETATION

To our knowledge, this study provides the first report of the association of collateral status with cCCT, and their interaction effect on functional outcome in AIS-LVO patients receiving EVT.

Cerebral Blood Flow Hemispheric Asymmetry in Comatose Adults Receiving Extracorporeal Membrane Oxygenation

Peripheral veno-arterial extracorporeal membrane oxygenation (ECMO) artificially oxygenates and circulates blood retrograde from the femoral artery, potentially exposing the brain to asymmetric perfusion. Though ECMO patients frequently experience brain injury, neurologic exams and imaging are difficult to obtain. Diffuse correlation spectroscopy (DCS) non-invasively measures relative cerebral blood flow (rBF) at the bedside using an optical probe on each side of the forehead. In this study we observed interhemispheric rBF differences in response to mean arterial pressure (MAP) changes in adult ECMO recipients. We recruited 13 subjects aged 21–78 years (7 with cardiac arrest, 4 with acute heart failure, and 2 with acute respiratory distress syndrome). They were dichotomized via Glasgow Coma Scale Motor score (GCS-M) into comatose (GCS-M ≤ 4; n = 4) and non-comatose (GCS-M > 4; n = 9) groups. Comatose patients had greater interhemispheric rBF asymmetry (ASYM_rBF) vs. non-comatose patients over a range of MAP values (29 vs. 11%, p = 0.009). ASYM_rBF in comatose patients resolved near a MAP range of 70–80 mmHg, while rBF remained symmetric through a wider MAP range in non-comatose patients. Correlations between post-oxygenator pCO₂ or pH vs. ASYM_rBF were significantly different between comatose and non-comatose groups. Our findings indicate that comatose patients are more likely to have asymmetric cerebral perfusion.

Quantification of Tumor Blush of Highly Vascularized Tumors with Slow Feeding System: Representative Use for Giant Pituitary Adenomas

BACKGROUND

 Modern imaging techniques can identify adverse factors for tumor removal such as cavernous sinus invasion before surgery, but surgeries for giant pituitary adenomas often reveal discrepancies between preoperative imaging and intraoperative findings because pituitary adenomas have feeding arteries with narrow diameters. Current imaging methods are not suitable for tumors with not only large vascular beds but also slow arterial filling.

PATIENTS AND METHODS

 This prospective study recruited 13 male subjects and 9 female subjects with giant pituitary adenomas between November 2011 and 2018. All the patients were investigated with three-dimensional magnetic resonance (MR) imaging, bone image computerized tomography (CT), and digital subtraction angiography (DSA) using a C-arm cone-beam CT scanner with a flat-panel detector and 50% diluted contrast medium. Fine angioarchitecture was evaluated and the tumor blush was quantified using newly developed region of interest (ROI) analysis to establish surgical strategies.

RESULTS

 Seven patients demonstrated no or very faint tumor blushes. In these patients, feeding arteries run centripetally from the surface of the tumor. Fifteen patients showed significant tumor blushes, and the feeding arteries penetrated centrifugally from the inferoposterior pole to the upper pole of the tumor. All the patients were treated according to the angiographic information with successful hemostasis. The patients showed improvement and/or disappearance of the neurologic deficits. The faint and significant blush groups showed significant differences in intraoperative bleeding (p < 0.01) and operation time (p < 0.05).

CONCLUSION

 Specialized evaluation focused on vascularization is required for successful therapy of giant pituitary adenomas.

Ophthalmic Artery Flow Pattern-related Stump Pressure and Ischemic Tolerance during Balloon Test Occlusion of the Internal Carotid Artery

Very few studies have described the blood flow pattern in the ipsilateral ophthalmic artery (OphA) during internal carotid artery (ICA) balloon test occlusion performed to estimate the risk of cerebral ischemia associated with therapeutic ICA sacrifice. This study aimed to investigate the relationship between ipsilateral OphA flow patterns just after ICA temporary occlusion and balloon test occlusion findings. We retrospectively reviewed 32 balloon test occlusion procedures performed at our institution between 2010 and 2019, and analyzed the OphA flow patterns and the conventional balloon test occlusion assessment items: neurological symptoms, stump pressure, stump-pressure ratio, collateral circulations, and venous phase delay. The flow patterns were categorized as type I (retrograde flow reaching the middle cerebral artery [MCA]), type II (retrograde flow to the ICA not reaching the MCA), or type III (no retrograde flow). Tolerance to balloon test occlusion was observed in 4/21 patients (19.0%), 4/6 patients (66.7%), and all five patients with types I, II, and III flows, respectively. The mean pressure ratios during balloon test occlusion in flow types I, II, and III were 35.6% ± 3.5%, 56.4% ± 6.5%, and 69.4% ± 7.1%, respectively (P <0.001). The mean stump pressures in flow types I, II, and III were 36.2 ± 3.6 mmHg, 46.6 ± 6.7 mmHg, and 66.6 ± 7.3 mmHg, respectively (P = 0.003). The mean venous phase delay in flow types I, II, and III were 0.99 ± 0.14 s, 0.25 ± 0.25 s, and 0.0 ± 0.28 s, respectively (P = 0.004). All the above variables showed significant flow-related differences. These results suggest that the OphA flow patterns may provide an additional diagnostic criterion for balloon test occlusion.

Flow diverter device placement for cerebral aneurysm is not effective for the patient with parent artery occlusion for contralateral aneurysm

PURPOSE

There have been many reports on the risks of enlargement and rupture of residual aneurysms and de novo aneurysm formation in the contralateral internal carotid artery after parent artery occlusion (PAO). In the present study, we investigated the efficacy of flow diverter device placement (FDDP) for the treatment of contralateral internal carotid artery aneurysms after PAO.

METHODS

After 11 patients, who had bilateral large or giant internal carotid aneurysms, were treated for either side with PAO or FDDP, they underwent FDDP for residual lesions in our hospital between October 2015 and June 2018. The patients were divided into two groups, depending on the prior procedure: PAO or FDDP. The embolic state after subsequent FDDP was evaluated by angiography. The embolic state was graded using the O'Kelly Marotta scale. Patients' characteristics and the embolic state of intracranial aneurysms after FDDP were compared between the two groups.

RESULTS

Comparing patients' characteristics between the PAO group and FDDP group, statistically significant differences were observed in laterality of the lesions and the interval between prior treatment and FDDP for residual aneurysms (p < 0.05). The embolic state at the one-year follow-up revealed that there could be significantly sufficient embolisation in the FDDP group (p < 0.05).

CONCLUSION

When FDDP is performed for the contralateral lesion after PAO treatment, it is difficult to attain sufficient embolisation of intracranial aneurysms because haemodynamic load in this procedure is large compared to that in a regular FDDP.

Computer Modeling of Clot Retrieval-Circle of Willis

Endovascular clot retrieval, often referred to as mechanical thrombectomy, has transformed the treatment of patients with ischemic stroke based on an underlying large cerebral vessel occlusion, ranging from the extracranial internal carotid artery (ICA) to the M1 (proximal) segment of the middle cerebral artery (MCA). The aim of this study was to evaluate the effect of a progressive occlusion of the extracranial portion of the ICA on the cerebral blood flow either with a conventional guiding catheter or a balloon-guiding catheter, which enables the operator to completely occlude the parent artery by inflating the balloon around the tip of this type of guiding catheter. We evaluated the impact of flow reduction in the ICA in the setting of ipsilateral MCA occlusion given the different configurations of the circle of Willis (CoW). The computer model of cerebral arteries was based on anatomical works by Rhoton (1) and van der Eecken (2). The interactive experimental results are available on the web at https://gntem3.shinyapps.io/ecrsim. In the setting of left MCA occlusion, compensation from the anterior and posterior communicating artery preserved the flow in the left anterior cerebral artery (ACA) but not the left MCA branches. Under selected CoW configurations, such as classic, missing Acom, or missing A1 segment of the ACA and concurrent right ICA occlusion, there was a progressive decrease of flow in the left ACA to a minimum of 78% when the simulated catheter fully occluded the left ICA. Flow collapsed (<10%) in the left ACA and MCA branches under CoW configurations, such as bilateral fetal PCA. In summary, compensatory flow collapsed under certain clot retrieval scenarios and unusual configurations of CoW.

Ischemic Tolerance Evaluated by Computed Tomography Perfusion during Balloon Test Occlusion

OBJECTIVES

Balloon test occlusion (BTO) is performed to evaluate ischemic tolerance for large and giant cerebral aneurysms and head and neck tumors that may require parent artery occlusion. However, ischemic tolerance for the temporary test occlusion does not always guarantee a tolerance for permanent occlusion. In this study, we evaluated the utility of computed tomography (CT) perfusion during BTO to quantify ischemic tolerance for detecting delayed ischemic stroke.

MATERIALS AND METHODS

Forty-one patients who underwent BTO for the internal carotid artery were included. The correlations between the parameters of CT perfusion and collateral angiographic appearance or stump pressure during BTO were evaluated. The cerebral blood flow (CBF), cerebral blood volume, mean transit time (MTT), and time to peak (TTP) were obtained through CT perfusion, and the asymmetry ratios were determined. Collateral angiographic appearances were categorized into 5 grades (0-4).

RESULTS

The collateral angiographic appearance showed moderate correlations with CBF, MTT, and TTP that was significant. Of these, the absolute value of the correlation coefficient was the highest for MTT. MTT also showed a moderate correlation with stump pressure. CBF and MTT were significantly different between the poor collateral group (grades 2 and 3) and the good collateral group (grade 4). Based on the MTT, the good collateral group was identified with high sensitivity (75.0%) and specificity (81.2%).

CONCLUSIONS

In BTO, the MTT obtained through CT perfusion showed a correlation with collateral angiographic appearance and stump pressure. Thus, the MTT might be useful to quantify ischemic tolerance for detecting delayed ischemic stroke.

"Clip Anchor-Assisted Coil Embolization" for Endovascular Parent Artery Occlusion of Intracranial Traumatic Aneurysm

Traumatic cerebral aneurysms are histologically dissecting aneurysms or pseudoaneurysms, thus requiring parent artery occlusion for cure. Combination of endovascular parent artery occlusion and extracranial-intracranial bypass is considered optimal to obtain complete obliteration of the aneurysm and to avoid hemodynamic hypoperfusion. However, endovascular parent artery occlusion of the supraclinoid internal carotid artery (ICA) is at risk of ischemic complications due to distal coil protrusion to adjacent perforating arteries or distal embolism of the thrombi generated in the coil mass. A 20-year-old man presented with progressive left optic neuropathy following motor vehicle accident. Radiological examination revealed left supraclinoid ICA aneurysmal formation with dissecting change. We treated this traumatic supraclinoid ICA aneurysm by combination of endovascular parent artery occlusion and high-flow bypass in the hybrid operating room. An aneurysmal clip was applied on the ICA just distal to the aneurysm prior to coil embolization, and worked as a scaffold for subsequent filling coils and as a blockade for the distal emboli. This "clip anchor-assisted coil embolization" technique resulted in optimal parent artery occlusion for the traumatic aneurysm of the supraclinoid ICA with minimal risks of residual blood flow, intraoperative rupture, and thromboembolic complications.

Magnetic Resonance Angiography-based Prediction of the Results of Balloon Test Occlusion

Precautious balloon test occlusion (BTO) is sometimes performed in cases of high-risk intraoperative internal carotid artery injury. We investigated whether magnetic resonance angiography (MRA) findings could predict BTO results to thus avoid the use of precautious BTO. This retrospective study, included 96 patients who underwent BTO, eight of whom underwent bilateral BTO. The relationship between the BTO results for 104 internal carotid arteries and the MRA findings obtained in 96 patients were retrospectively evaluated. On MRA, anterior cerebral artery (A1)–anterior communicating artery–A1 was defined as anterior collateral circulation (ACC), and posterior cerebral artery–posterior communicating artery was defined as posterior collateral circulation (PCC). BTO was tolerated in all 27 sides with thick ACC regardless of PCC thickness. In 31 of 44 cases with a thin ACC, the tested sides were BTO-tolerant (70.5%). Of these 44 tested sides, all five with a thick PCC were BTO-tolerant, but eight with a thin PCC and 31 with an invisible PCC showed results other than tolerance. Among cases with an invisible ACC, 10 of 33 tested sides were BTO-tolerant (30.3%). Among these 33 tested sides, outcomes other than tolerance were observed regardless of PCC thickness. Thick, thin, and invisible ACCs were assigned 3, 1, and 0 points, respectively; and thick, thin, and invisible PCCs were assigned 2, 1, and 0 points, respectively. A sum of 3 points in the ACC and PCC indicated that all sides were BTO-tolerant. In conclusion, a thick ACC or a thin ACC with a thick PCC indicates BTO-tolerance. The BTO prediction score is useful for predicting results of BTO.

Efficacy and Safety of Endovascular Treatment in Patients with Internal Carotid Artery Occlusion and Collateral Middle Cerebral Artery Flow

Objective

In patients with internal carotid artery (ICA) occlusion, collateral middle cerebral artery (MCA) flow has a protective role against ischemia. However, some of these patients may experience initial major neurological deficits and major worsening on following days. Thus, we investigated the safety and efficacy of endovascular treatment (EVT) for ICA occlusion with collateral MCA flow by comparing clinical outcomes of medical treatment versus EVT.

Methods

The inclusion criteria were as follows : 1) acute ischemic stroke with ICA occlusion and presence of collateral MCA flow on transfemoral cerebral angiography (TFCA) and 2) hospital arrival within 12 hours from symptom onset. The treatment strategy was made by the attending physician based on the patient’s clinical status and results of TFCA.

Results

Eighty-one patients were included (30 medical treatment, 51 EVT). The EVT group revealed a high incidence of intracranial ICA occlusion, longer ipsilesional MCA contrast filling time, and a similar rate of favorable clinical outcome despite a higher mean baseline the National Institutes of Health Stroke Scale (NIHSS) score. By binary logistic regression analysis, intravenous recombinant tissue plasminogen activator and EVT were independent predictors of favorable clinical outcome. In subgroup analysis based on stroke etiology, the non-atherosclerotic group showed a higher baseline NIHSS score, higher incidence of EVT, and a higher rate of distal embolization during EVT in comparison with the atherosclerotic group.

Conclusion

In patients with ICA occlusion and collateral MCA flow, decisions regarding treatment strategy based on TFCA can help achieve favorable clinical outcomes. EVT strategy with respect to etiology of ICA occlusion might help achieve better angiographic outcomes.

Transient Aggravation of Hypopituitarism After Parent Artery Occlusion with Low-Flow Bypass for Unruptured Giant Cavernous Carotid Aneurysm

BACKGROUND

Hypopituitarism is not well known after the treatment of a cavernous carotid aneurysm extending to the sellar region by the parent artery occlusion and bypass surgery.

CASE DESCRIPTION

A 60-year-old female presented with a 2-year-old progressive visual disturbance. The patient had no pituitary hormone-related symptoms or signs, but elevated prolactin and decreased free thyroxin levels are shown on blood examination. Neuroimages revealed a right giant partially thrombosed cavernous carotid aneurysm compressing the sella turcica markedly. The aneurysm was treated by the right cervical internal carotid artery ligation with the right superficial temporal artery-middle cerebral artery double anastomoses. The patient had headache, general fatigue, chilling, and hypoactivity on postoperative day 6, when aneurysmal mass effects were transiently increased on neuroimages, associated with hypocortisolism and hyponatremia. Hydrocortisone administration improved the symptoms and was tapered off at 8 months post surgery, as the aneurysm shrank and pituitary hormone values were normalized except for prolactin.

CONCLUSION

Hypopituitarism should be taken into consideration even after the parent artery occlusion with bypass surgery for a giant carotid aneurysm compressing the sella turcica.

Comparison of practical methods in clinical sites for estimating cerebral blood flow during balloon test occlusion

OBJECTIVE

The authors sought to compare methods of measurement for venous phase delay (VPD) or mean stump pressure (MSTP) to rank their potential to predict ischemic tolerance during balloon test occlusion in the internal carotid artery, exploring a more correlative and convenient way to measure cerebral blood flow (CBF) that could be utilized even in the acute phase or in institutions not adequately equipped to measure CBF during the test.

METHODS

X-ray angiography perfusion analysis using diagnostic digital subtraction angiography (DSA) equipment enables 1-step examination (without any room-to-room transfer of patients) to measure CBF, VPD, and MSTP completely simultaneously, which has not been accomplished by any previous perfusion studies.

RESULTS

This analysis was applied to 17 patients and resulted in successful estimation of all 3 parameters in each case. The average VPD of several cortical veins had a strong correlation with relative CBF (rCBF) between bilateral hemispheres with a correlation coefficient of 0.89443, a correlation as strong as that (0.90357) of the "approximate VPD," which is interpreted based on the trend line of the scatterplot of the time to peak contrast opacification in cortical veins and their spatial positioning from the median sagittal plane. MSTP and classic visual determination of VPD have weaker correlation coefficients with rCBF (0.56119 and 0.70048, respectively). Overall, subjective visual determination in combination with the calculation of the trend line to estimate VPD provided a considerably strong correlation with rCBF (R = 0.86660) without any dedicated software or hardware.

CONCLUSIONS

VPD has a stronger correlation with rCBF than MSTP. rCBF could be successfully predicted on common DSA equipment, even by visual determination without expensive software, if the trend line is adopted for processing to estimate VPD.

Difference in Cerebral Circulation Time between Subtypes of Moyamoya Disease and Moyamoya Syndrome

In this study, we evaluated the differences in hemodynamics between hemorrhagic and non-hemorrhagic moyamoya disease (MMD) and moyamoya syndrome (MMS) by measuring cerebral circulation time (CCT). This case-control study included 136 patients with MMD or MMS diagnosed between April 2015 and July 2016 at Beijing Tian Tan Hospital. Each hemisphere was analyzed separately. The difference in clinical, radiological characteristics and CCT between subtypes of MMD and MMS were analyzed statistically. The results showed that total CCT between hemorrhagic and non-hemorrhagic sides was not statistically different (16.55 s vs. 16.06 s, P = 0.562). The cerebral filling circulation time (CFCT) of hemorrhagic sides was significantly shorter than that of non-hemorrhagic sides (4.52 s vs. 5.41 s, P < 0.001), and the cerebral venous circulation time (CVCT) of hemorrhagic sides was significantly longer than that of non-hemorrhagic sides (12.02 s, vs. 10.64 s, P < 0.001). The ratio of CFCT to CVCT (F-V ratio) was inversely correlated with the possibility of hemorrhagic stroke. Therefore, we conclude that the rapid filling and poor venous drainage of cerebral circulation are likely risk factors of hemorrhagic stroke secondary to MMD or MMS. The F-V ratio can be used to identify individuals at high risk of hemorrhagic stroke.

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

PURPOSE

The aim of our study is to explore the impacts of different deconvolution algorithms on correlations between CBF, MTT, CBV, TTP, Tmax from MR perfusion (MRP) and angiography cerebral circulation time (CCT).

METHODS

Retrospectively, 30 patients with unilateral carotid stenosis, and available pre-stenting MRP and angiography were included for analysis. All MRPs were conducted in a 1.5-T MR scanner. Standard singular value decomposition, block-circulant, and two delay-corrected algorithms were used as the deconvolution methods. All angiographies were obtained in the same bi-plane flat-detector angiographic machine. A contrast bolus of 12mL was administrated via angiocatheter at a rate of 8mL/s. The acquisition protocols were the same for all cases. CCT was defined as the difference between time to peak from the cavernous ICA and the parietal vein in lateral view. Pearson correlations were calculated for CCT and CBF, MTT, CBV, TTP, Tmax.

RESULTS

The correlation between CCT and MTT was highest with Tmax (r=0.65), followed by MTT (r=0.60), CBF (r=-0.57), and TTP (r=0.33) when standard singular value decomposition was used. No correlation with CBV was noted.

CONCLUSIONS

MRP using a singular value decomposition algorithm confirmed the feasibility of quantifying cerebral blood flow deficit in steno-occlusive disease within the angio-room. This approach might further improve patient safety by providing immediate cerebral hemodynamics without extraradiation and iodine contrast.

Cortical Venous Filling on Dynamic Computed Tomographic Angiography: A Novel Predictor of Clinical Outcome in Patients With Acute Middle Cerebral Artery Stroke

BACKGROUND AND PURPOSE

Venous flow in the downstream territory of an occluded artery may influence patient prognosis after ischemic stroke. Our aim was to study cortical venous filling (CVF) in a time-resolved manner with dynamic computed tomographic angiography and to assess the relationship with clinical outcome.

METHODS

Patients with a proximal middle cerebral artery occlusion underwent noncontrast CT and whole-brain CT perfusion/dynamic CT angiography within 9 hours after stroke-onset. We defined poor outcome as a modified Rankin Scale score of ≥3. Association between the extent and velocity of CVF and poor outcome at 3 months was analyzed with Poisson-regression. Prognostic value of optimal CVF (maximum opacification of cortical veins) in addition to age, stroke severity, treatment, Alberta Stroke Program Early CT score, cerebral blood flow, and collateral status was assessed with logistic regression and summarized with the area under the curve.

RESULTS

Eighty-eight patients were included, with a mean age of 67 years. By combining the extent and velocity of optimal CVF, we observed a decreased risk of poor outcome in patients with good and fast optimal CVF, risk ratio of 0.5 (95% confidence interval, 0.3-0.7). Extent and velocity of optimal CVF had additional prognostic value (area under the curve, 0.88; 95% confidence interval, 0.77-0.98; P<0.02) compared with a model without CVF information.

CONCLUSIONS

The combination of extent and velocity of optimal CVF, as assessed with dynamic CT angiography, is useful to identify patients with acute middle cerebral artery stroke at higher risk of poor clinical outcome at 3-month follow-up.

CLINICAL TRIAL REGISTRATION

URL: http://www.trialregister.nl/trialreg and http://www.clinicaltrials.gov. Unique identifier: NTR1804 and NCT00880113, respectively.

Parametric Digital Subtraction Angiography Imaging for the Objective Grading of Collateral Flow in Acute Middle Cerebral Artery Occlusion

PURPOSE

To report the feasibility of parametric color-coded digital subtraction angiography (DSA) in complementing the traditional, subjective way of leptomeningeal collateral assessment in acute middle cerebral artery (MCA) occlusions.

METHODS

Thirty-three consecutive patients with acute MCA occlusion who received endovascular treatment were recruited for investigation. Eighteen of 33 consecutive patients were included. The target downstream territory (TDT) of MCA and reference point at terminal internal carotid artery of each patient was contoured by 5 raters independently on the basis of anteroposterior 2-dimensional DSA. Two parameters of relative maximum density of TDT (rDensitymax) and peak time interval (ΔPT) between reference and TDT were extracted by the use of parametric DSA analysis software. Interrater reliability was tested with intraclass correlation coefficients. Parameters with sufficient interrater reliability entered validity evaluation. Then, the correlation test with the American Society of Interventional and Therapeutic Neuroradiology collateral grading system and efficacy in predicting favorable clinical outcome was evaluated.

RESULTS

The intraclass correlation coefficient of rDensitymax and ΔPT were 0.983, 95% confidence interval 0.968-0.993 and 0.831, 95% confidence interval 0.705-0.923, respectively. The parameter rDensitymax showed a strong correlation with the American Society of Interventional and Therapeutic Neuroradiology collateral grading system score (r of Spearman correlation test = 0.869, P < 0.001) and mRS at 3 months (partial correlation coefficient = 0.616, P = 0.009), whereas ΔPT_average did not. A cut-off point of 0.224 in rDensitymax predicted a favorable clinical outcome with high sensitivity and specificity.

CONCLUSIONS

The relative maximum contrast density of MCA territory on 2-dimensional DSA measured by parametric imaging technique appears to be a simple and reliable metric for the assessment of leptomeningeal collaterals in cases of acute MCA occlusion.

Cerebral Blood Flow after Acute Bypass with Parent Artery Trapping in Patients with Ruptured Supraclinoid Internal Carotid Artery Aneurysms

BACKGROUND

Bypass with parent artery trapping is an alternative treatment method for ruptured internal carotid artery (ICA) aneurysms when clipping or coiling is contraindicated. However, the efficacy and safety of this strategy during the acute stage of subarachnoid hemorrhage (SAH) is undetermined.

METHODS

A retrospective review of 955 consecutive patients presenting SAH between 2006 and 2014 identified 17 patients with ruptured ICA aneurysms treated by bypass with parent artery trapping within 72 hours after the bleeding (bypass group). The 26 cases with ruptured posterior communicating artery aneurysms treated with clipping during the same period were defined as a control group (clipping group). Postoperative cerebral blood flow (CBF) was evaluated by single photon emission computed tomography (SPECT). We analyzed the postoperative hemodynamic status, surgical complications, and the clinical outcomes.

RESULTS

Postoperative rebleeding did not occur in any of the cases. CBF in the first postoperative week in the bypass group was lower than that in the clipping group (P = .0165). This CBF decrease improved in the second postoperative week and did not differ from that of the clipping group. The incidence of acute ischemic complications was significantly higher in the bypass group (P = .0284), but the incidence of delayed cerebral ischemia did not differ between the 2 groups. The incidence of favorable outcomes at 6 months was 82.4% in the bypass group and 81% in the clipping group.

CONCLUSIONS

Although the transient CBF decrease with acute ischemic complications should be noted, acute bypass with parent artery trapping is safe and effective for unclippable/uncoilable ruptured ICA aneurysms.

Delayed Transcranial Echo-Contrast Bolus Arrival in Unilateral Internal Carotid Artery Stenosis and Occlusion

Some patients with internal carotid artery (ICA) occlusion or stenosis are at risk of developing a hemodynamic stroke. Transcranial ultrasonography using an echo-contrast bolus technique might be able to assess the extent of hemodynamic compromise. We describe a transcranial Doppler sonographic method that analyzes the differences in echo-contrast bolus arrival between both middle cerebral arteries after intravenous echo-contrast application. Ten patients with 50%-79% ICA stenosis, 10 patients with 80%-99% ICA stenosis and 22 patients with ICA occlusion were studied and compared with 15 age-matched controls. There were significant increases in delayed filling of the middle cerebral artery in both 80%-99% stenoses and occlusions compared with controls. The extent of the observed delays did not correlate with vasomotor reactivity. Echo-contrast bolus arrival time can be used to gain additional information on the intracranial hemodynamic effects of extracranial carotid artery disease that seems to be independent of the established ultrasound indices.

Rescue Bypass for Revascularization After Ischemic Complications in the Treatment of Giant or Complex Intracranial Aneurysms

BACKGROUND

Surgical trapping or endovascular deconstruction commonly is used for the treatment of giant or complex intracranial aneurysms. Preoperative balloon test occlusion and cerebral blood flow studies and intraoperative neurophysiologic monitoring can indicate whether sufficient collateralization exists or whether revascularization is needed. Hemodynamic insufficiency can occur, however, despite passing these tests, necessitating posttreatment revascularization.

METHODS

We conducted a retrospective review of patients who underwent surgical or endovascular parent vessel occlusion for the management of giant or complex intracranial aneurysms and subsequently required rescue bypass for symptoms of hemodynamic insufficiency. Pre- and postrevascularization functional status was measured with the modified Rankin Scale.

RESULTS

During a 15-year period from 1997 to 2012, a rescue bypass was performed in 5 patients each harboring a giant or complex intracranial internal carotid artery (ICA) aneurysm that was treated with surgical trapping or endovascular deconstruction in a previous procedure. All bypasses were extracranial-to-intracranial and included cervical ICA to middle cerebral artery, subclavian to middle cerebral artery, and cervical ICA to supraclinoid ICA anastomoses via either a saphenous vein or radial artery graft. Functional outcome at time of last follow-up was improved in each patient (improvement in modified Rankin Scale of 1-3 points).

CONCLUSIONS

Ischemic complications must always be anticipated in the treatment of giant or complex intracranial aneurysms, even if pre- and intraoperative blood flow studies indicate sufficient collateralization. Here we show that extracranial-to-intracranial bypass is an effective option to rescue unanticipated hemodynamic insufficiency after parent vessel occlusion. This study emphasizes the need for cerebrovascular surgeons to maintain proficiency in complex bypass techniques.

Cerebral circulation time is prolonged and not correlated with EDSS in multiple sclerosis patients: a study using digital subtracted angiography

Literature has suggested that changes in brain flow circulation occur in patients with multiple sclerosis. In this study, digital subtraction angiography (DSA) was used to measure the absolute CCT value in MS patients and to correlate its value to age at disease onset and duration, and to expand disability status scale (EDSS). DSA assessment was performed on eighty MS patients and on a control group of forty-four age-matched patients. CCT in MS and control groups was calculated by analyzing the angiographic images. Lesion and brain volumes were calculated in a representative group of MS patients. Statistical correlations among CCT and disease duration, age at disease onset, lesion load, brain volumes and EDSS were considered. A significant difference between CCT in MS patients (mean = 4.9s; sd = 1.27s) and control group (mean = 2.8s; sd = 0.51s) was demonstrated. No significant statistical correlation was found between CCT and the other parameters in all MS patients. Significantly increased CCT value in MS patients suggests the presence of microvascular dysfunctions, which do not depend on clinical and MRI findings. Hemodynamic changes may not be exclusively the result of a late chronic inflammatory process.

Noninvasive photoacoustic measurement of the composite indicator dilution curve for cardiac output estimation

Recently, the measurement of indicator dilution curves using a photoacoustic (PA) technology was reported, which showed promising results on the noninvasive estimation of cardiac output (CO) that is an important hemodynamic parameter useful in various clinical situations. However, in clinical practice, measuring PA indicator dilution curves from an arterial blood vessel requires an ultrasound transducer array capable of focusing on the targeted artery. This causes several challenges on the clinical translation of the PA indicator dilution method, such as high sensor cost and complexity. In this paper, we theoretically derived that a composite PA indicator dilution curve simultaneously measured from both arterial and venous blood vessels can be used to estimate CO correctly. The ex-vivo and in-vivo experimental results with a flat ultrasound transducer verified the developed theory. We believe this new concept would overcome the main challenges on the clinical translation of the noninvasive PA indicator dilution technology.

Monitoring balloon test occlusion of the internal carotid artery with transcranial Doppler. A case report and literature review

Angiographic balloon test occlusion (BTO) allows preoperative risk evaluation of patients undergoing permanent therapeutic occlusion of the internal carotid artery (ICA). The sensitivity of the BTO can be increased using different complementary techniques. Transcranial Doppler (TCD) stands out as a non-invasive, bedside method providing real-time monitoring of cerebral haemodynamics, therefore accurately identifying patients at risk of stroke. A case of a 30-year-old woman with a giant intracavernous aneurysm of the left ICA presenting with subacute left VI nerve palsy is described. A pre-operative TCD- and EEG-monitored BTO of the left ICA was performed. The 16.7% drop found in the middle cerebral artery's peak systolic velocity (PSVMCA) predicts clinical and haemodynamic tolerance to the permanent loss of that vessel. This case illustrates the potential of TCD monitoring during temporary BTO of the ICA. It highlights its ability to provide a complete preclinical evaluation of collateralization and autoregulatory adaptation to unilateral ICA occlusion. TCD may also decrease the time of occlusion required for the BTO.