An optimization model for reducing thrombectomy center rotations while maintaining medical accessibility

BACKGROUND/PURPOSE

This study addresses the delicate balance between healthcare personnel burnout and medical accessibility in the context of endovascular thrombectomy (EVT) services in urban areas. We aimed to determine the minimum number of hospitals providing EVT on rotation each day without compromising patient access.

METHODS

Employing an optimization model, we developed shift schedules based on patient coverage rates and volumes during the pre-pandemic (2016-2018) and pandemic (2019-2021) periods. Starting with a minimum of two hospitals on duty per day, we gradually increased to a maximum of eight. Patient coverage rates, defined as the proportion of patients meeting bypass criteria and transported to rotating hospitals capable of EVT, were the primary outcomes. Sensitivity analyses explored the impact of varying patient transport intervals and accumulating patients over multiple years.

RESULTS

Results from 7024 patient records revealed patient coverage rates of 92.5% (standard deviation [SD] 2.8%) during the pre-pandemic and 91.4% (SD 2.8%) during the pandemic, with at least two rotating hospitals daily. No significant differences were observed between schedules based on the highest patient volume and coverage rate months. A patient coverage rate of 98.99% was achieved with four rotating hospitals per day during the pre-pandemic period, with limited improvement beyond this threshold. Changing patient transport intervals and accumulating patients over six years (p = 0.83) had no significant impact on coverage rates.

CONCLUSION

Our optimization model supports reducing the number of daily rotating hospitals by half while preserving a balance between patient accessibility and alleviating strain on medical teams.

Vascular compactness of unruptured brain arteriovenous malformation predicts risk of hemorrhage after stereotactic radiosurgery

The aim of the study was to investigate whether morphology (i.e. compact/diffuse) of brain arteriovenous malformations (bAVMs) correlates with the incidence of hemorrhagic events in patients receiving Stereotactic Radiosurgery (SRS) for unruptured bAVMs. This retrospective study included 262 adult patients with unruptured bAVMs who underwent upfront SRS. Hemorrhagic events were defined as evidence of blood on CT or MRI. The morphology of bAVMs was evaluated using automated segmentation which calculated the proportion of vessel, brain tissue, and cerebrospinal fluid in bAVMs on T2-weighted MRI. Compactness index, defined as the ratio of vessel to brain tissue, categorized bAVMs into compact and diffuse types based on the optimal cutoff. Cox proportional hazard model was used to identify the independent factors for post-SRS hemorrhage. The median clinical follow-ups was 62.1 months. Post-SRS hemorrhage occurred in 13 (5.0%) patients and one of them had two bleeds, resulting in an annual bleeding rate of 0.8%. Multivariable analysis revealed bAVM morphology (compact versus diffuse), bAVM volume, and prescribed margin dose were significant predictors. The post-SRS hemorrhage rate increased with larger bAVM volume only among the diffuse nidi (1.7 versus 14.9 versus 30.6 hemorrhage per 1000 person-years in bAVM volume < 20 cm3 versus 20-40 cm3 versus > 40 cm3; p = 0.022). The significantly higher post-SRS hemorrhage rate of Spetzler-Martin grade IV-V compared with grade I-III bAVMs (20.0 versus 3.3 hemorrhages per 1000 person-years; p = 0.001) mainly originated from the diffuse bAVMs rather than the compact subgroup (30.9 versus 4.8 hemorrhages per 1000 person-years; p = 0.035). Compact and smaller bAVMs, with higher prescribed margin dose harbor lower risks of post-SRS hemorrhage. The post-SRS hemorrhage rate exceeded 2.2% annually within the diffuse and large (> 40 cm3) bAVMs and the diffuse Spetzler-Martin IV-V bAVMs. These findings may help guide patient selection of SRS for the unruptured bAVMs.

Applying ONCO-RADS to whole-body MRI cancer screening in a retrospective cohort of asymptomatic individuals

BACKGROUND

Whole-body magnetic resonance imaging (WB-MRI) has emerged as a valuable tool for cancer detection. This study evaluated the prevalence rates of cancer in asymptomatic individuals undergoing WB-MRI according to the Oncologically Relevant Findings Reporting and Data System (ONCO-RADS) classifications in order to assess the reliability of the classification method.

METHODS

We retrospectively enrolled 2064 asymptomatic individuals who participated in a WB-MRI cancer screening program between 2017 and 2022. WB-MRI was acquired on a 3-T system with a standard protocol, including regional multisequence and gadolinium-based contrast agent-enhanced oncologic MRI. Results of further examinations, including additional imaging and histopathology examinations, performed at our institute were used to validate the WB-MRI findings. Two radiologists blinded to the clinical outcome classified the WB-MRI findings according to the ONCO-RADS categories as follows: 1 (normal), 2 (benign finding highly likely), 3 (benign finding likely), 4 (malignant finding likely), and 5 (malignant finding highly likely). Firth logistic regression analysis was performed to determine the associations between participant characteristics and findings of ONCO-RADS category ≥ 4.

RESULTS

Of the 2064 participants with median age of 55 years, 1120 (54.3%) were men, 43 (2.1%) had findings of ONCO-RADS category ≥ 4, and 24 (1.2%) had confirmed cancer. The cancer prevalence rates were 0.1%, 5.4%, 42.9%, and 75% for ONCO-RADS categories 2, 3, 4, and 5, respectively. In the multivariable model, older age (OR: 1.035, p = 0.029) and history of hypertension (OR: 2.051, p = 0.026), hepatitis B carrier (OR: 2.584, p = 0.013), or prior surgery (OR: 3.787, p < 0.001) were independently associated with the findings for ONCO-RADS category ≥ 4.

CONCLUSIONS

The ONCO-RADS categories for cancer risk stratification were validated and found to be positively correlated with cancer risk. The application of ONCO-RADS facilitates risk-based management after WB-MRI for cancer screening.

Natural History and Histopathology of Expanding Cysts and Hematomas After Stereotactic Radiosurgery for Arteriovenous Malformations of the Brain: A Case Series

BACKGROUND

We reviewed the clinical course and histopathologic findings for cases involving the formation of expanding cysts and/or hematomas after gamma knife surgery (GKS) for arteriovenous malformations (AVMs).

METHODS

We report a single-center retrospective review of 18 patients who presented with cyst and/or hematoma expansion after GKS for AVMs between 1993 and 2023. Expanding cysts and hematomas were defined as well-demarcated cavities filled with fluid or well-marginated heterogenous hematomas presenting with expansion proximal to or in the location of the original AVM, respectively. Patient demographics, AVM characteristics, history of interventions and surgeries, and imaging and histopathologic features of expanding cysts and hematomas were collected for analysis.

RESULTS

Among 1072 AVM patients treated using GKS, 18 presented with expanding cysts or hematomas during a total follow-up period of 16,757 patient-years (0.11 case/100 persons/patient-year). The time to cyst or hematoma identification was 4-13 years after initial GKS, with a mean duration of 8.6 years. Among the patients examined, 7 (38.9%) presented mainly with hematoma, 10 (55.6%) presented mainly with cysts, and 1 presented with approximately equal components of both. Among the 18 patients, 13 (72.2%) underwent craniotomy to treat cyst or hematoma expansion. All the specimens had similar histopathologic characteristics, including organizing hematoma with fresh and old hemorrhage, fibrinoid necrosis of the vessels, gliosis of normal brain tissue, infiltration of hemosiderin-laden histiocytes, and extravascular protein leakage.

CONCLUSIONS

Our findings suggest that the formation of these 2 complications can be attributed to a common mechanism involving radiation-induced vascular damage in brain tissue adjacent to the AVM and subsequent chronic inflammation and capillary dilatation.

Magnetic resonance radiomics-derived sphericity correlates with seizure in brain arteriovenous malformations

OBJECTIVES

Angioarchitectural analysis of brain arteriovenous malformations (BAVMs) is qualitative and subject to interpretation. This study quantified the morphology of and signal changes in the nidal and perinidal areas by using MR radiomics and compared the performance of MR radiomics and angioarchitectural analysis in detecting epileptic BAVMs.

MATERIALS AND METHODS

From 2010 to 2020, a total of 111 patients with supratentorial BAVMs were retrospectively included and grouped in accordance with the initial presentation of seizure. Patients' angiograms and MR imaging results were analyzed to determine the corresponding angioarchitecture. The BAVM nidus was contoured on time-of-flight MR angiography images. The perinidal brain parenchyma was contoured on T2-weighted images, followed by radiomic analysis. Logistic regression analysis was performed to determine the independent risk factors for seizure. ROC curve analysis, decision curve analysis (DCA), and calibration curve were performed to compare the performance of angioarchitecture-based and radiomics-based models in diagnosing epileptic BAVMs.

RESULTS

In multivariate analyses, low sphericity (OR: 2012.07, p = .04) and angiogenesis (OR: 5.30, p = .01) were independently associated with a high risk of seizure after adjustment for age, sex, temporal location, and nidal volume. The AUC for the angioarchitecture-based, MR radiomics-based, and combined models was 0.672, 0.817, and 0.794, respectively. DCA confirmed the clinical utility of the MR radiomics-based and combined models.

CONCLUSIONS

Low nidal sphericity and angiogenesis were associated with high seizure risk in patients with BAVMs. MR radiomics-derived tools may be used for noninvasive and objective measurement for evaluating the risk of seizure due to BAVM.

CLINICAL RELEVANCE STATEMENT

Low nidal sphericity was associated with high seizure risk in patients with brain arteriovenous malformation and MR radiomics may be used as a noninvasive and objective measurement method for evaluating seizure risk in patients with brain arteriovenous malformation.

KEY POINTS

• Low nidal sphericity was associated with high seizure risk in patients with brain arteriovenous malformation. • The performance of MR radiomics in detecting epileptic brain arteriovenous malformations was more satisfactory than that of angioarchitectural analysis. • MR radiomics may be used as a noninvasive and objective measurement method for evaluating seizure risk in patients with brain arteriovenous malformation.

Association Between Pseudoprogression of Vestibular Schwannoma After Radiosurgery and Radiological Features of Solid and Cystic Components

BACKGROUND AND OBJECTIVES

The pathophysiology of vestibular schwannoma (VS) pseudoprogression after Gamma Knife radiosurgery (GKRS) remains unclear. Radiological features in pretreatment magnetic resonance images may help predict VS pseudoprogression. This study used VS radiological features quantified using an automated segmentation algorithm to predict pseudoprogression after GKRS treatment.

METHODS

This is a retrospective study comprising 330 patients with VS who received GKRS. After image preprocessing and T2W/contrast-enhanced T1-weighted image (CET1W) image generation, with fuzzy C-means clustering, VSs were segmented into solid and cystic components and classified as solid and cystic. Relevant radiological features were then extracted. The response to GKRS was classified into "nonpseudoprogression" and "pseudoprogression/fluctuation". The Z test for two proportions was used to compare solid and cystic VS for the likelihood of pseudoprogression/fluctuation. Logistic regression was used to assess the correlation between clinical variables and radiological features and response to GKRS.

RESULTS

The likelihood of pseudoprogression/fluctuation after GKRS was significantly higher for solid VS compared with cystic VS (55% vs 31%, P < .001). For the entire VS cohort, multivariable logistic regression revealed that a lower mean tumor signal intensity (SI) in T2W/CET1W images was associated with pseudoprogression/fluctuation after GKRS ( P = .001). For the solid VS subgroup, a lower mean tumor SI in T2W/CET1W images ( P = .035) was associated with pseudoprogression/fluctuation after GKRS. For the cystic VS subgroup, a lower mean SI of the cystic component in T2W/CET1W images ( P = .040) was associated with pseudoprogression/fluctuation after GKRS.

CONCLUSION

Pseudoprogression is more likely to occur in solid VS compared with cystic VS. Quantitative radiological features in pretreatment magnetic resonance images were associated with pseudoprogression after GKRS. In T2W/CET1W images, solid VS with a lower mean tumor SI and cystic VS with a lower mean SI of cystic component were more likely to have pseudoprogression after GKRS. These radiological features can help predict the likelihood of pseudoprogression after GKRS.

Noninvasive investigations of human glymphatic dynamics in a diseased model

OBJECTIVES

To explore human glymphatic dynamics in a diseased model via a noninvasive technique.

METHODS

Patients with reversible vasoconstriction syndrome (RCVS) presenting with blood-brain barrier disruption, i.e., para-arterial gadolinium leakage on 3-T 3-dimensional isotropic contrast-enhanced T2-fluid-attenuated inversion recovery (CE-T2-FLAIR) magnetic resonance imaging (MRI), were prospectively enrolled. Consecutive 9-min-CE-T2-FLAIR for 5-6 times (early panel) after intravenous gadolinium-based contrast agent (GBCA) administration and one time-varying deferred scan of noncontrast T2-FLAIR (delayed panel) were performed. In Bundle 1, we measured the calibrated signal intensities (cSIs) of 10 different anatomical locations. In Bundle 2, brain-wide measurements of para-arterial glymphatic volumes, means, and medians of the signal intensities were conducted. We defined mean (mCoIs) or median (mnCoIs) concentration indices as products of volumes and signal intensities.

RESULTS

Eleven subjects were analyzed. The cSIs demonstrated early increase (9 min) in perineural spaces: (cranial nerve [CN] V, p = 0.008; CN VII + VII, p = 0.003), choroid plexus (p = 0.003), white matter (p = 0.004) and parasagittal dura (p = 0.004). The volumes, mCoIs, and mnCoIs demonstrated increasing rates of enhancement after 9 to 18 min and decreasing rates after 45 to 54 min. The GBCA was transported centrifugally and completely removed within 961-1086 min after administration.

CONCLUSIONS

The exogenous GBCA leaked into the para-arterial glymphatics could be completely cleared around 961 to 1086 min after administration in a human model of BBB disruption. The tracer enhancement started variously in different intracranial regions but was eventually cleared centrifugally to brain convexity, probably towards glymphatic-meningeal lymphatics exits.

CLINICAL RELEVANCE STATEMENT

Glymphatic clearance time intervals and the centrifugal directions assessed by a noninvasive approach may have implications for clinical glymphatic evaluation in the near future.

KEY POINTS

• This study aimed to investigate the human glymphatic dynamics in a noninvasive diseased model. • The intracranial MR-detectable gadolinium-based contrast agents were removed centrifugally within 961 to 1086 min. • The glymphatic dynamics was demonstrable by enhancing MRI in an in vivo diseased model noninvasively.

The applicability of the "surprise question" as a prognostic tool in patients with severe chronic comorbidities in a university teaching outpatient setting

BACKGROUND

Life expectancy in recent decades has increased the prevalence of chronic diseases in the population, requiring an approach to new health topics, such as discussions on quality of life and expectations about death and dying. The concept of advance directives (ADs) gives individuals the opportunity to make known their decisions about the treatments they would like to receive at the end of life. Despite the recognition of relevance in clinical practice, the applicability of the concept presents challenges, including establishing the appropriate prognosis for each patient and the ideal time to approach the patient. Some prognostic tools were developed, such as the surprise question (SQ): "Would you be surprised if your patient died in 12 months?", which is used in some clinical settings to predict patient deaths and to make decisions regarding ADs. The main objective of the present study was to evaluate the behavior of second-year resident physicians (PGY-2) when the SQ was applied.

METHOD

In our observational study, from July 1, 2016, to February 28, 2017, (PGY-2) in the Internal Medicine Residency Program (IMRP) applied SQ to all patients with multiple and varied chronic no communicable comorbidities, who were followed up at the general medicine outpatient clinic (GMOC) of a tertiary university hospital in São Paulo- Brazil. The frequency of the outcome (death or non-death within 12 months) was analyzed by correlating it with the clinical data (impact of the studied variables).

RESULTS

Eight hundred forty patients entered the study. Fitfty-two of them (6.2%) died within one year. PGY-2 predicted that two hundred and fourteen patients (25.5% of total) would die within a year (answer No to SQ), of which, 32 (14.9%) did so. The correct residents' prognosis for the subgroup of 626 patients (answer "Yes" to SQ) was NPV = 96.8% (CI = 95.4%-98.2%) and PPV = 14.9% (CI 10.1%-19, 6%). Answering "Yes" to SQ correlated negatively to addressing AD while the outcomes death and the answer No to SQ were positively correlated, according to the number of comorbidities.

CONCLUSION

The SQ, in addition to care, contributed to health education, communication and care planning shared by the doctor and patient.

Improved survival and intracranial tumor control of EGFR-mutated NSCLC patients with newly developed brain metastases following stereotactic radiosurgery and EGFR-TKI: a large retrospective cohort study and meta-analyses

PURPOSE

To examine the differential effects of SRS and TKI on EGFR-mutated NSCLC patients with brain metastases (BMs) and outcomes following continuation of the same TKI agent in case of new BMs.

METHODS

This study included 608 NSCLC patients (2,274 BMs) while meta-analyses included 1,651 NSCLC patients (> 3,944 BMs). Overall survival (OS) and intracranial progression free survival (iPFS) were estimated using Kaplan-Meier methods. Hazard ratios (95% CI) of prognostic factors were estimated using Cox regression models.

RESULTS

The median OS/iPFS (95% CI) (months) for patients with wildtype EGFR/ALK, EGFR mutations, and ALK rearrangements were 17.7 (12.9-23.6)/12.1 (9.8-15.6), 28.9 (23.8-33.3)/17.7 (14.8-21.2), and 118.0 (not reached)/71.7 (15.1-not reached), respectively. In EGFR-mutated patients, meta-analyses combining our data showed significantly improved OS and iPFS of patients who received SRS and TKI (OS:35.1 months, iPFS:20.0 months) when compared to those who have SRS alone (OS:20.8 months, iPFS:11.8 months) or TKI alone (OS:24.3 months, iPFS:13.8 months). Having SRS for newly diagnosed BMs while keeping the existing TKI agent yielded OS (30.0 vs. 32.1 months, p = 0.200) non-inferior to patients who started combined SRS and TKI therapy for their newly diagnosed NSCLC with BMs. Multivariable analyses showed that good performance score and TKI therapy were associated with improved outcomes.

CONCLUSIONS

Combined SRS and TKI resulted in favorable outcomes in EGFR-mutated NSCLC patients with newly diagnosed BMs. Continuation of the same TKI agent plus SRS in case of new brain metastases yielded good clinical outcomes and may be considered a standard-of-care treatment.

Is it advisable to perform radiosurgery for EGFR-TKI-controlled brain metastases? A retrospective study of the role of radiosurgery in lung cancer treatment

PURPOSE

Given the availability of TKIs with high central nervous system efficacy, the question arises as to whether upfront SRS provides additional clinical benefits. The goal of this study was to characterize the clinical outcomes of SRS as salvage therapy for TKI-uncontrolled BMs.

METHODS

This retrospective study included EGFR-mutant NSCLC patients presenting BMs at the time of primary tumor diagnosis. BMs were categorized into three subgroups, referred to as "Nature of TKI-treated BMs", "TKI-controlled brain metastases ± SRS", and "SRS salvage therapy". The first subgroup analysis characterized the effects of TKIs on tumor behavior. In the second subgroup, we compared outcomes of TKI-controlled BMs treated with TKI alone versus those treated with combined TKI-SRS therapy. The third subgroup characterized the outcomes of TKI-uncontrolled BMs treated with SRS as salvage therapy Clinical outcomes include local and distant tumor control.

RESULTS

This study included 106 patients with a total of 683 BMs. TKI treatment achieved control in 63% of local tumors at 24 months. Among the TKI-controlled BMs, local tumor control was significantly higher in the combined TKI-SRS group (93%) than in the TKI-alone group (65%) at 24 months (p < 0.001). No differences were observed between the two groups in terms of distant tumor control (p = 0.832). In dealing with TKI-uncontrolled BMs, salvage SRS achieved local tumor control in 58% of BMs at 24 months.

CONCLUSIONS

While upfront TKI alone proved highly effective in BM control, this study also demonstrated the outcomes of SRS when implemented concurrently with TKI or as salvage therapy for TKI-uncontrolled BMs. This study also presents a strategy of the precise timing and targeting of SRS to lesions in progression.

Estimating Pulsatile Flow Velocity using Four-Dimensional Digital Subtraction Angiography. Annu Int Conf IEEE Eng Med Biol Soc 2023;2023:1-4. [PMID: 38082691 DOI: 10.1109/embc40787.2023.10340843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Digital subtraction angiography (DSA) is a X-ray based imaging modality for interventional procedures, and remains criterion standard for diagnosing vascular diseases. The imaging protocol of DSA involves administration of a foreign contrast medium into the blood vessel that opacifies the vasculature during the imaging. Using two-dimensional (2D) DSA with high temporal resolution, it was recently demonstrated that the pulsatile velocity can be estimated by evaluating the temporal and spatial variations of the contrast medium distributions in the blood vessel. In this paper, we evaluate the feasibility to estimate the pulsatile flow velocity using the four-dimensional (4D) DSA. To overcome the noise and artefacts of 4D-DSA data, a empirical mode decomposition plus autocorrelation based method is proposed to estimate the pulsatile velocities, and the pulsatile velocities estimated using 2D-DSA are used as reference for comparison.Clinical Relevance-4D-DSA encompasses both structural and temporal information; it theoretically reduces the need of multiple scans, hence reducing the radiation doses. The estimated pulsatile flow velocities open up a new parameter for hemodynamic studies and potential for real-time diagnostic and therapeutic monitoring during interventional procedures.

Stereotactic radiosurgery for orbital cavernous hemangiomas

OBJECTIVE

The goal of this study was to assess the safety and efficacy of single-session Gamma Knife radiosurgery (GKRS) for orbital cavernous hemangiomas (OCHs).

METHODS

Patients who presented with an OCH between September 1999 and May 2022 and were treated with single-session GKRS were included in this single-center cohort study.

RESULTS

There were 23 patients (7 males and 16 females) in this study. The median margin dose was 12 Gy (range 11-13 Gy). The median clinical and radiological follow-ups were 45 months (range 5-190 months) and 45 months (range 6-190 months), respectively. Nine (69.2%) of 13 patients with visual acuity impairment had improvement in best corrected visual acuity. Of the 8 patients with visual field defects, 5 patients (62.5%) had complete resolution. Tumor regression was observed in 22 patients (95.7%). The mean relative reduction in tumor volume was 82.6% ± 23.7%. The relative reductions in tumor volume were 33%, 49%, 72%, 84%, and 89% at 6, 12, 24, 36, and 48 months, respectively. Adverse effects of radiation were not observed.

CONCLUSIONS

GKRS appears to be safe and efficacious for treating OCHs over long-term follow-up. The treatment is associated with a high rate of regression in OCHs and remarkable improvement in both visual acuity and visual field deficits.

Improved Measurement of the Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Reactor neutrino experiments play a crucial role in advancing our knowledge of neutrinos. In this Letter, the evolution of the flux and spectrum as a function of the reactor isotopic content is reported in terms of the inverse-beta-decay yield at Daya Bay with 1958 days of data and improved systematic uncertainties. These measurements are compared with two signature model predictions: the Huber-Mueller model based on the conversion method and the SM2018 model based on the summation method. The measured average flux and spectrum, as well as the flux evolution with the ^{239}Pu isotopic fraction, are inconsistent with the predictions of the Huber-Mueller model. In contrast, the SM2018 model is shown to agree with the average flux and its evolution but fails to describe the energy spectrum. Altering the predicted inverse-beta-decay spectrum from ^{239}Pu fission does not improve the agreement with the measurement for either model. The models can be brought into better agreement with the measurements if either the predicted spectrum due to ^{235}U fission is changed or the predicted ^{235}U, ^{238}U, ^{239}Pu, and ^{241}Pu spectra are changed in equal measure.

Precision Measurement of Reactor Antineutrino Oscillation at Kilometer-Scale Baselines by Daya Bay

We present a new determination of the smallest neutrino mixing angle θ_{13} and the mass-squared difference Δm_{32}^{2} using a final sample of 5.55×10^{6} inverse beta-decay (IBD) candidates with the final-state neutron captured on gadolinium. This sample is selected from the complete dataset obtained by the Daya Bay reactor neutrino experiment in 3158 days of operation. Compared to the previous Daya Bay results, selection of IBD candidates has been optimized, energy calibration refined, and treatment of backgrounds further improved. The resulting oscillation parameters are sin^{2}2θ_{13}=0.0851±0.0024, Δm_{32}^{2}=(2.466±0.060)×10^{-3}  eV^{2} for the normal mass ordering or Δm_{32}^{2}=-(2.571±0.060)×10^{-3}  eV^{2} for the inverted mass ordering.

Single flow diverter to manage multiple intracranial aneurysms in a parent artery

BACKGROUND

Endovascular coil embolization has become an important method in the management of intracranial aneurysm. However, simultaneously coiling multiple intracranial aneurysms (MIAs) in unilateral parent artery in one-stage may fail or insufficient in geographic difficult aneurysm. Flow diverter (FD) has the potential to manage MIAs with nonamenable to coiling. Herein, we report periprocedural morphologic change and outcomes using single FD to manage unruptured MIAs in a parent artery.

METHODS

Over a 3-year period, a total of 63 patients with 126 MIAs successful managed by single FD with complete angiographic follow-up. There were 49 women and 14 men, with ages ranging from 42 to 77 years (mean: 59 years). We retrospectively assessed the clinical data, aneurysm characteristic, angiographic and clinical outcomes of all patients and compared with 171 patients with single aneurysm managed by FD.

RESULTS

Sixty-one patients with 118 aneurysms (94%) located in internal carotid artery or middle cerebral artery (n = 4, 3%), two patients with four aneurysms (4%) were found in the basilar artery. The mean aneurysm size was 5.6 mm (range from 1.8 to 38 mm). Mean angiographic follow-up was 14 months. Complete obliteration of aneurysm was achieved in 102 aneurysms (83%), subtotal or partial aneurysm obliteration was demonstrated in 18 aneurysms (15%), unchanged aneurysm morphology in three (2%). Aneurysm morphology synchronized alteration in 55 patients (87%), other eight patients (13%) with 16 aneurysms showed different morphologic alteration in angiographic follow-up. Four patients (6.3%) had intraprocedural ischemic complication. During the follow-up period, 61 patients (97%) were neurologic stable; there was no hemorrhagic or ischemic event.

CONCLUSION

Single FD was feasible to treat MIAs in a parent artery with both effective and safe in one-stage management. Most aneurysms synchronized alteration of morphology in a mid-term follow-up. The procedure was almost the same with FD managing single aneurysm, but longer FD is needed in MIAs.

Quantified flow and angioarchitecture show similar associations with hemorrhagic presentation of brain arteriovenous malformations

INTRODUCTION

The purpose of our study was to elucidate the impact of brain arteriovenous malformation (BAVM) flow and wall shear stress (WSS) on angioarchitecture and to evaluate their association with hemorrhagic presentations.

MATERIALS AND METHODS

Forty-one patients with BAVMs were evaluated by phase-contrast MR angiography. Volume flow rate and WSS were quantified. Angioarchitectural features such as location, angiogenesis, venous stenosis, venous ectasia, venous phlebitis, venous rerouting, exclusive deep vein and venous sac were evaluated by two neuroradiologists. The correlation between BAVM flow and size was evaluated with Spearman correlation coefficients. Differences of size, flow, and WSS between the hemorrhagic and non-hemorrhagic groups, the seizure and non-seizure groups, and between the different groups based on angioarchitecture were evaluated with Mann-Whitney U tests. Accuracy in predicting hemorrhage was evaluated with receiver operating characteristic curves.

RESULT

BAVM flow was highly correlated with volume (ρ = 0.77). Higher flow was more commonly associated with angiogenesis, venous ectasia, venous rerouting, and venous phlebitis. Flow and angioarchitecture showed similar efficacy in differentiating hemorrhagic from non-hemorrhagic BAVMs. WSS did not demonstrate differences across any clinical groups.

CONCLUSION

Flow quantification and angioarchitecture analysis of BAVMs showed similar efficacy as evaluated by associations with hemorrhagic presentation. High flow affects both arterial and venous angioarchitecture, reflecting the nature of low vascular resistance in BAVMs.

Gamma Knife Radiosurgery Irradiation of Surgical Cavity of Brain Metastases: Factor Analysis and Gene Mutations

(1) Background: Surgical resection for the removal of brain metastases often fails to prevent tumor recurrence within the surgical cavity; hence, researchers are divided as to the benefits of radiation treatment following surgical resection. This retrospective study assessed the effects of post-operative stereotactic radiosurgery (SRS) on local tumor control and overall survival. (2) Methods: This study examined the demographics, original tumor characteristics, and surgical outcomes of 97 patients who underwent Gamma Knife Radiosurgery (GKRS) treatment (103 brain metastases). Kaplan-Meier plots and Cox regression were used to correlate clinical features to tumor control and overall survival. (3) Results: The overall tumor control rate was 75.0% and overall 12-month survival was 89.6%. Tumor control rates in the radiation group versus the non-radiation group were as follows: 12 months (83.1% vs. 57.7%) and 24 months (66.1% vs. 50.5%). During the 2-year follow-up period after SRS, the intracranial response rate was higher in the post-craniotomy radiation group than in the non-radiation group (p = 0.027). Cox regression multivariate analysis determined that post-craniotomy irradiation of the surgical cavity is predictive of tumor control (p = 0.035). However, EGFR mutation was not predictive of overall survival or tumor control. (4) Conclusions: Irradiating the surgical cavity after surgery can enhance local tumor control; however, it does not have a significant effect on overall survival.

Dispersion of Heterogeneous Medium in Pulsatile Blood Flow and Absolute Pulsatile Flow Velocity Quantification

Heterogeneous medium enhanced angiogr- ams are key diagnostic tools in clinical practice; the associated hemodynamic information is crucial for diagnosing cardiovascular diseases. However, the dynamics of such medium in physiological blood flow are poorly understood. Herein, we report a previously unnoticed dispersion pattern, which is a universal phenomenon, of a medium in pulsatile blood flow. We present a physical theory for studying the dispersion of a steadily injected heterogeneous medium into a thin tubular blood vessel in which the blood flow is pulsatile. In a thin tubular blood vessel, we demonstrate that variations of concentration associated with the heterogeneous medium obey a one-dimensional advection diffusion equation, and the diffusion has limited effect whenever a short vascular segment is considered. A distinct feature of the distribution of the medium in the axial distance-time plane is a "dilation-retraction" pattern. The time evolution signals at different axial positions exhibit distinct concentration waveforms. A numerical scheme is proposed for exploiting this information to estimate the pulsatile velocity. Artificial data are adopted to validate the scheme. Real X-ray angiography is also analyzed to support our theory and method. The theory is applicable whenever imaging protocols involve a heterogeneous medium in pulsatile flow.

Compactness index: a radiosurgery outcome predictor for patients with unruptured brain arteriovenous malformations

OBJECTIVE

The goal of the study was to define and quantify brain arteriovenous malformation (bAVM) compactness and to assess its effect on outcomes after Gamma Knife radiosurgery (GKRS) for unruptured bAVMs.

METHODS

Unsupervised machine learning with fuzzy c-means clustering was used to differentiate the tissue constituents of bAVMs on T2-weighted MR images. The percentages of vessel, brain, and CSF were quantified. The proposed compactness index, defined as the ratio of vasculature tissue to brain tissue, categorized bAVM morphology into compact, intermediate, and diffuse types according to the tertiles of this index. The outcomes of interest were complete obliteration and radiation-induced changes (RICs).

RESULTS

A total of 209 unruptured bAVMs treated with GKRS were retrospectively included. The median imaging and clinical follow-up periods were 49.2 and 72.3 months, respectively. One hundred seventy-three bAVMs (82.8%) achieved complete obliteration after a median latency period of 43.3 months. The rates of RIC and permanent RIC were 76.1% and 3.8%, respectively. Post-GKRS hemorrhage occurred in 14 patients (6.7%), resulting in an annual bleeding risk of 1.0%. Compact bAVM, smaller bAVM volume, and exclusively superficial venous drainage were independent predictors of complete obliteration. Diffuse bAVM morphology, larger bAVM volume, and higher margin dose were independently associated with RICs.

CONCLUSIONS

The compactness index quantitatively describes the compactness of unruptured bAVMs. Moreover, compact bAVMs may have a higher obliteration rate and a smaller risk of RICs than diffuse bAVMs. This finding could help guide decision-making regarding GKRS treatment for patients with unruptured bAVMs.

Magnetic resonance imaging signal characteristics associated with prognosis of skull base chordoma after gamma knife radiosurgery

OBJECTIVE

To investigate the association between the magnetic resonance imaging (MRI) signal characteristics of skull base chordoma and radiosurgical outcomes.

METHODS

Twenty-four patients with skull base chordomas treated with Gamma Knife radiosurgery (GKRS) after previous surgical resection were retrospectively (2001-2021) examined. Pre-GKRS MRIs were analyzed for R_T2 (tumor-to-brainstem signal intensity ratio on T2-weighted imaging), R_CE (tumor-to-brainstem signal intensity ratio on contrast-enhanced T1-weighted imaging), and mean apparent diffusion coefficient (ADC). Correlations of the parameters with patient survival and local tumor progression were made by using Cox regression and Kaplan-Meier analyses.

RESULTS

During a median follow-up of 46 months after GKRS, 9 patients died with significantly more local tumor progression events (median number: 2 vs 0, P = .012) than did 15 alive patients. On multivariable analysis, higher mean ADC was associated with longer patient survival (P = .016) after GKRS. The actuarial 5-year overall survival rates were 88.9% versus 54.7% for chordomas with an ADC of ≥ 1270 × 10^-6 mm²/s versus < 1270 × 10^-6 mm²/s. R_T2 < 1.5 (P = .038) and R_CE > 1.57 (P = .022) were associated with a lower probability of local tumor control.

CONCLUSION

Lower mean ADC values are associated with shorter patient survival in skull base chordomas after GKRS. Diffusion-weighted imaging may help in GKRS planning and outcome prediction for these patients.

Leukoencephalopathy in patients with brain metastases who received radiosurgery with or without whole brain radiotherapy

BACKGROUND

Whole brain radiation therapy (WBRT) for brain metastases (BMs) is a common cause of radiation-induced leukoencephalopathy; however the safety of alternative stereotactic radiosurgery (SRS) remains unclear. This study examined the incidence of leukoencephalopathy in patients treated with SRS alone versus WBRT plus SRS for BMs with a focus on the relationship between prognostic factors and leukoencephalopathy.

METHODS

Analysis was performed between 2002 and 2021. The total enrollment was 993 patients with the distribution: WBRT plus SRS (n = 291) and SRS only (n = 702). Leukoencephalopathy was graded from 0 to 3 for changes in white matter indicated by the MRI after WBRT or SRS. Patient characteristics and SRS dosimetric parameters were reviewed to identify factors that contributed to the incidence of leukoencephalopathy or overall survival.

RESULTS

The incidence of leukoencephalopathy was consistently higher in WBRT plus SRS group than in SRS alone group (p < 0.001). Leukoencephalopathy was also associated with a larger total tumor volume (≧28cm³; p = 0.028) and age (> 77 years; p = 0.025). Nonetheless, the SRS integral dose to skull in the subgroup of WBRT plus SRS treatment was not demonstrated significance in development of leukoencephalopathy (p = 0.986 for integral dose 1-2 J, p = 0.776 for integral dose > 2 J).

CONCLUSIONS

This study revealed that SRS is safe for oligo-BMs in terms of leukoencephalopathy development. Patient age and total tumor volume were identified as important factors in assessing the development of leukoencephalopathy. The additional of SRS (even at an integral dose > 2 J) did not increase the incidence of leukoencephalopathy.

Observation of a Strongly Isospin-Mixed Doublet in ^{26}Si via β-Delayed Two-Proton Decay of ^{26}P

β decay of proton-rich nuclei plays an important role in exploring isospin mixing. The β decay of ^{26}P at the proton drip line is studied using double-sided silicon strip detectors operating in conjunction with high-purity germanium detectors. The T=2 isobaric analog state (IAS) at 13 055 keV and two new high-lying states at 13 380 and 11 912 keV in ^{26}Si are unambiguously identified through β-delayed two-proton emission (β2p). Angular correlations of two protons emitted from ^{26}Si excited states populated by ^{26}P β decay are measured, which suggests that the two protons are emitted mainly sequentially. We report the first observation of a strongly isospin-mixed doublet that deexcites mainly via two-proton decay. The isospin mixing matrix element between the ^{26}Si IAS and the nearby 13 380-keV state is determined to be 130(21) keV, and this result represents the strongest mixing, highest excitation energy, and largest level spacing of a doublet ever observed in β-decay experiments.

Leptomeningeal metastasis in patients with non-small cell lung cancer after stereotactic radiosurgery for brain metastasis

OBJECTIVE

Stereotactic radiosurgery (SRS) is an effective treatment for brain metastases (BMs) in patients with non-small cell lung cancer (NSCLC). However, factors associated with the development of post-SRS leptomeningeal metastasis (LM) remain unclear. The authors analyzed the incidence and risk factors of LM development in patients with NSCLC and BMs after SRS and examined the survival outcomes and prognostic factors after LM development.

METHODS

This retrospective study included patients with NSCLC treated with SRS for MRI-diagnosed BM from 2002 to 2021. The authors recorded various clinical and demographic data, including age, sex, tumor histology, molecular profile of tumors, extracranial disease status, previous craniotomy, Karnofsky Performance Status, systemic treatments, tumor volume, and number of BMs. The management and survival outcomes after LM diagnosis were also recorded.

RESULTS

LM developed in 13.7% of patients with NSCLC and BMs after SRS treatment. Large initial tumor volume and more than 5 BM lesions, but not EGFR mutation status and post-SRS treatment, were associated with LM development after SRS. Multivariate analysis revealed that chemotherapy and targeted therapy after LM were associated with better survival in patients with LM after SRS.

CONCLUSIONS

This study is the first to evaluate the risk factors for LM in a relatively large cohort of patients with NSCLC after SRS. In patients with BMs harboring risk factors for subsequent LM, such as initial tumor volume and number of metastatic lesions, aggressive therapies with high CNS penetrating ability should be considered.

Outflow Patency Correlates with Radiosurgical Outcomes of Lateral Sinus Dural Arteriovenous Fistula

OBJECTIVE

To explore the impact of outflow patency on radiosurgical outcomes of lateral sinus dural arteriovenous fistulas (DAVFs).

METHODS

We retrospectively examined 83 lateral sinus DAVFs treated with Gamma Knife radiosurgery (GKRS) between 1995 and 2020. Two neuroradiologists blinded to the therapeutic outcomes served as imaging evaluators on pre-GKRS digital subtraction angiography and magnetic resonance images. The sinovenous outflow of lateral sinus DAVF was scored using combined conduit score (CCS), ranging from 0 (total occlusion) to 8 (full patency). The patients' follow-up magnetic resonance and digital subtraction angiography images were used to validate the radiosurgical outcomes (obliteration or non-obliteration) of lateral sinus DAVF. Cox regression and Kaplan-Meier analyses were performed to determine the correlations between the variables and outcomes.

RESULTS

Among the 83 cases, 60 (72%) lateral sinus DAVFs achieved obliteration after a GKRS at a median latency period of 24.5 months. After adjustment for aggressive presentation, cortical venous reflux, straight sinus reflux, and optic nerve sheath enlargement, a CCS of >6 was independently associated with lateral sinus DAVF obliteration (hazard ratio: 2.335, P = 0.007). The estimated 36-month probabilities of obliteration were 80% versus 53.6% for lateral sinus DAVFs with a CCS of >6 versus ≤6.

CONCLUSIONS

Lateral sinus DAVFs with a CCS of >6, indicating a nearly patent sinovenous outflow, were more likely to be obliterated after GKRS. Sinovenous outflow patency is a factor associated with therapeutic outcomes in radiosurgery for lateral sinus DAVFs.

First Measurement of High-Energy Reactor Antineutrinos at Daya Bay

This Letter reports the first measurement of high-energy reactor antineutrinos at Daya Bay, with nearly 9000 inverse beta decay candidates in the prompt energy region of 8-12 MeV observed over 1958 days of data collection. A multivariate analysis is used to separate 2500 signal events from background statistically. The hypothesis of no reactor antineutrinos with neutrino energy above 10 MeV is rejected with a significance of 6.2 standard deviations. A 29% antineutrino flux deficit in the prompt energy region of 8-11 MeV is observed compared to a recent model prediction. We provide the unfolded antineutrino spectrum above 7 MeV as a data-based reference for other experiments. This result provides the first direct observation of the production of antineutrinos from several high-Q_{β} isotopes in commercial reactors.

Plasma Matrix Metalloproeteinase-9 Is Associated with Seizure and Angioarchitecture Changes in Brain Arteriovenous Malformations

Both angiogenesis and inflammation contribute to activation of matrix metalloproeteinase-9 (MMP-9), which dissolves the extracellular matrix, disrupts the blood-brain barrier, and plays an important role in the pathogenesis of brain arteriovenous malformations (BAVMs). The key common cytokine in both angiogenesis and inflammation is interleukin 6 (IL-6). Previous studies have shown elevated systemic MMP-9 and decreased systemic vascular endothelial growth factor (VEGF) in BAVM patients. However, the clinical utility of plasma cytokines is unclear. The purpose of this study is to explore the relationship between plasma cytokines and the clinical presentations of BAVMs. Prospectively, we recruited naive BAVM patients without hemorrhage as the experimental group and unruptured intracranial aneurysm (UIA) patients as the control group. All patients received digital subtraction angiography, and plasma cytokines were collected from the lesional common carotid artery. Plasma cytokine levels were determined using a commercially available, monoclonal antibody-based enzyme-linked immunosorbent assay. Subgroup analysis based on hemorrhagic presentation and angiograchitecture was done for the BAVM group. Pearson correlations were calculated for the covariates. Means and differences for continuous and categorical variables were compared using Student's t and χ² tests respectively. Plasma MMP-9 levels were significantly higher in the BAVM group (42,945 ± 29,991 pg/mL) than in the UIA group (28,270 ± 17,119 pg/mL) (p < 0.001). Plasma MMP-9 levels in epileptic BAVMs (57,065 ± 35,732; n = 9) were higher than in non-epileptic BAVMs (35,032 ± 28,301; n = 19) (p = 0.049). Lower plasma MMP-9 levels were found in cases of BAVM with angiogenesis and with peudophlebitis. Plasma MMP-9 is a good biomarker reflecting ongoing vascular remodeling in BAVMs. Angiogenesis and pseudophlebitis are two angioarchitectural signs that reflect MMP-9 activities and can potentially serve as imaging biomarkers for epileptic BAVMs.

Flow diverter manages very small aneurysm of the internal carotid artery

BACKGROUND

Endovascular aneurysm coiling is a minimally invasive method to manage intracranial aneurysms. However, aneurysm coiling may fail in very small aneurysms (VSAs); thus, flow diverter (FD) is recommended as an alternative in these difficult aneurysms. Herein, we report our experience and outcomes of FD to treat VSA of the internal carotid artery (ICA).

METHODS

Over a 3-year period, a total of 70 patients with 87 unruptured VSAs of the ICA were managed by FD. There were 54 men and 16 women, with a mean age of 57 (range, 41-75) years. We retrospectively assessed the clinical data, aneurysm characteristics, and angiographic as well as clinical outcomes of patients treated by FD and compared with larger aneurysms.

RESULTS

Fifty aneurysms (58%) were located in the supraclinoid ICA, followed by paraclinoid ICA (n = 31, 36%) and cavernous ICA (n = 6, 7%). Most aneurysms (n = 72, 83%) were between 2 and 3 mm in size. The mean aneurysm size was 2.3 mm (range, 1.5-3 mm). Follow-up angiographic data (mean, 13 months) were available in 54 patients with 68 aneurysms. Successful FD deployment in an ideal position to bride aneurysm was achieved in 86 of 87 aneurysms (99%). Complete obliteration (CO) was achieved in 63 aneurysms (93%). Compared with larger aneurysms (>3 mm), VSAs had the tendency to achieve CO ( p < 0.05) in a midterm follow-up. Two patients (2.8%) had intraprocedural complications, including in-stent thrombosis (n = 1) and distal embolism (n = 1). One patient (1.4%) suffered from mild limb weakness.

CONCLUSION

The use of FD to manage VSA was technically feasible, and the procedure was simpler than those of larger aneurysms. FD stenting of VSAs was confirmed to be effective and safe and had higher CO rate than those in larger aneurysms in a midterm angiographic follow-up.

Clinical characteristics and long-term outcome of cerebral cavernous malformations-related epilepsy

OBJECTIVE

Cerebral cavernous malformations (CCMs) present variably and epileptic seizures are the most common symptom. The factors contributing to cavernoma-related epilepsy (CRE) and drug resistance remain inconclusive. The outcomes of CRE after different treatment modalities have not yet been fully addressed. This study aimed to characterize the clinical features of patients with CRE and the long-term seizure outcomes of medical and surgical treatment strategies.

METHODS

This was a retrospective cohort of 135 patients with CCM who were diagnosed in 2007~2011 and followed up for 93.6 months on average. The patients were divided into drug-resistant epilepsy (DRE) (n = 29), non-DRE (NDRE) (n = 45), and no epilepsy (NE) (n = 61).

RESULTS

Temporal CCM was the factor most strongly associated with the development of both CRE and DRE. The majority of patients with single temporal CCMs had CRE (86.8%, n = 33) and 50% had DRE, whereas only 14.7% (n = 5) with a non-temporal supratentorial CCM had DRE (P < 0.05). The most common lesion site in the DRE group was the mesiotemporal lobe (50%). Multiple CCMs were more frequently observed in the CRE (29.2%) than the NE (11.5%) group (P < 0.05). In patients with CRE, multiple lesions were associated with a higher rebleeding rate (odds ratio: 11.1), particularly in those with DRE (odds ratio: 15.4). The majority of patients who underwent resective surgery for DRE (76.5%, n = 13) achieved ILAE class I and II seizure outcomes even after a long disease course.

SIGNIFICANCE

Temporal CCM not only predisposes to CRE but is also a major risk factor for drug resistance. The mesiotemporal lobe is the most epileptogenic zone. Multiple CCMs are another risk factor for CRE and increase the rebleeding risk in these patients. Surgical resection could provide beneficial long-term seizure outcomes in patients with DRE.

Imaging Markers Associated With Radiation-Induced Changes in Brain Arteriovenous Malformations After Radiosurgery

BACKGROUND

Radiation-induced changes (RICs) in brain tissue, seen as increased perinidal T2-weighted hyperintensity on MRI, are commonly observed in patients with brain arteriovenous malformations (BAVMs) within 2 years after Gamma Knife (Elekta) radiosurgery (GKRS).

OBJECTIVE

To explore the imaging markers associated with RICs in patients with BAVMs.

METHODS

We retrospectively included 106 treatment-naïve patients with BAVMs who received GKRS alone between 2011 and 2018 and had ≥24 months of clinical and MRI follow-up. Pre-GKRS angiography and MRIs were analyzed for morphological characteristics and quantitative digital subtraction angiography parameters. RIC severity was categorized as mild (grade I), moderate (grade II), or severe (grade III). Firth logistic regression analysis was conducted to determine the associations between the parameters and RICs.

RESULTS

Among the 106 patients, 83 (78.3%) developed RICs, with 16 categorized as grade I, 62 as grade II, and 5 as grade III. RICs were symptomatic in 19 patients (17.9%). In multivariable models, BAVMs with a volume of >5 cm3 (odds ratio [OR]: 4.322, P = .024) and neoangiogenesis on angiography before treatment (OR: 3.846, P = .029), and thrombus within nidus or drainage vein on follow-up MRI (OR: 3.679, P = .001) were independently associated with grade II or III RICs. Symptomatic RICs were more likely to develop in basal ganglia or brainstem.

CONCLUSION

Large BAVMs and neoangiogenesis were associated with moderate to severe RICs in treatment-naïve patients with BAVMs. Our findings may assist with the complication risk assessment for these patients.

Flow-diverter stent to manage intracranial aneurysms: A single center experience

BACKGROUND

Endovascular coil embolization is an important method for managing intracranial aneurysms. However, aneurysm coiling may fail or be insufficient in geographically difficult aneurysms. A flow-diverter stent (FDS) is an alternative in these difficult coiling aneurysms. Thus, this study reports the experience and outcome of FDS management of intracranial aneurysms.

METHODS

Over 29 months, FDS treated 125 patients with 163 intracranial unruptured aneurysms. This study enrolled 31 men and 94 women, ranging from 17 to 81 years (mean, 58 years). Clinical data, aneurysm characteristics, and angiographic and clinical outcomes of patients treated by FDS were retrospectively assessed.

RESULTS

The current study found 151 (93%) aneurysms in the internal carotid artery. Most aneurysms (n = 118; 72%) were small (<7 mm). The mean aneurysm size was 6.2 mm (range, 2-38 mm). Follow-up angiography was available in 53 patients with 74 aneurysms (mean, 13 months). Successful FDS deployment in an ideal position was found in 125 of 130 patients (96%). Complete obliteration (CO) was achieved in 58 aneurysms (78%) in the mean 13-month angiographic follow-up. Smaller aneurysms (<7 mm) had a CO tendency than larger aneurysms (p < 0.01) in midterm follow-up. Seven patients (5.6%) had intraprocedural complications (in-stent thrombosis, three patients; distal embolic, two patients; iatrogenic carotid-cavernous fistula, and subarachnoid hemorrhage, one patient). Two patients (1.6%) suffered from permanent procedure-related morbidity (n = 1) or mortality (n = 1). No late hemorrhagic events or stent displacement occurred during the follow-up period.

CONCLUSION

Despite few procedural complications and some pieces of evidence of insufficient aneurismal treatment in a midterm angiographic follow-up, FDS was effective and safe in managing intracranial unruptured aneurysms, particularly in smaller aneurysms, which had better CO than larger ones.

Joint Determination of Reactor Antineutrino Spectra from ^{235}U and ^{239}Pu Fission by Daya Bay and PROSPECT

A joint determination of the reactor antineutrino spectra resulting from the fission of ^{235}U and ^{239}Pu has been carried out by the Daya Bay and PROSPECT Collaborations. This Letter reports the level of consistency of ^{235}U spectrum measurements from the two experiments and presents new results from a joint analysis of both data sets. The measurements are found to be consistent. The combined analysis reduces the degeneracy between the dominant ^{235}U and ^{239}Pu isotopes and improves the uncertainty of the ^{235}U spectral shape to about 3%. The ^{235}U and ^{239}Pu antineutrino energy spectra are unfolded from the jointly deconvolved reactor spectra using the Wiener-SVD unfolding method, providing a data-based reference for other reactor antineutrino experiments and other applications. This is the first measurement of the ^{235}U and ^{239}Pu spectra based on the combination of experiments at low- and highly enriched uranium reactors.

Cerebrospinal fluid diversion and outcomes for lung cancer patients with leptomeningeal carcinomatosis

OBJECTIVE

To investigate the outcomes of cerebrospinal fluid (CSF) diversion in lung cancer patients with leptomeningeal carcinomatosis (LMC).

METHODS

A retrospective review of consecutive lung cancer patients with LMC suffering from increased intracranial pressure (IICP) and hydrocephalus between February 2017 and February 2020. We evaluated the survival benefit of CSF diversion surgery and assessed the outcomes of treatments administered post-LMC in terms of overall survival and shunt-related complications.

RESULTS

The study cohort included 50 patients (median age: 59 years). Ventricular peritoneal (VP) shunts were placed in 33 patients, and lumbar peritoneal (LP) shunts were placed in 7 patients. Programmable shunts were placed in 36 patients. Shunt adjustment was performed in 19 patients. Kaplan-Meier analysis revealed that shunt placement increased overall survival from 1.95 months to 6.21 months (p = 0.0012) and increased Karnofsky Performance Scores (KPS) from 60 to 70. Univariate analysis revealed no difference between VP or LP shunts in terms of survival. No differences in post-shunt systemic treatments (tyrosine kinase inhibitors (TKIs) or systemic treatments) were observed in overall survival. Shunt-related complications were noted in 7 patients, including shunt obstruction (n = 4), infection (n = 1), and over-drainage (n = 2).

CONCLUSION

CSF diversion (VP or LP shunt) appears to be an effective and safe treatment for lung cancer patients with LMC and hydrocephalus. Programmable shunts should be considered for complex cases, which commonly require pressure adjustments as the disease progresses.

Risk factors of recurrent carotid blowout syndrome and strategy of endovascular management

BACKGROUND

Carotid blowout syndrome (CBS) is a catastrophic complication after aggressive head and neck cancer treatment. Endovascular embolization is an effective modality to manage CBS. However, some CBS may have recurrent CBS (rCBS) after endovascular management. This study aims to report the potential rCBS risk and endovascular management strategy.

METHODS

Of the 225 patients with CBS referred for embolization in 13 years, 31 men and one woman (mean age, 55 years) with 35 rCBS with pseudoaneurysms formation were identified after endovascular management. Moreover, the rCBS preembolization angioarchitecture, rCBS cause, rCBS time interval, embolic materials selection, and final embolization clinical/angiographic outcomes were retrospectively analyzed.

RESULTS

rCBS with pseudoaneurysm due to disease progression (DP) occurred in 17 patients, while 15 patients had insufficient embolization (IE) with 18 rCBS. The mean rCBS timing interval was 76 days with 129 and 12 days due to DP or IE. The most common rCBS locations were the carotid bulb and the main trunk of the external carotid artery (n = 20, 57%), followed by internal carotid artery (n = 8, 23%), distal branch of the external carotid artery (n = 4, 11%), and common carotid artery (n = 3, 9%). Endovascular management was technically successful in all patients by reconstruction (n = 7, 20%) or destruction (n = 28, 80%) techniques. Three patients (9%) had procedure-related complications. No rCBS was observed in all affected arteries after the last embolization in a mean 11-month clinical follow-up.

CONCLUSION

rCBS may result from DP or IE. The common location of IE-related rCBS usually occurred in the carotid branches. It occurred within two weeks of CBS largely because of the underestimation of the extension of the affected carotid artery. In addition, DP is natural in head and neck cancer after aggressive treatment. Thus, endovascular management remained an effective method to manage rCBS.

Combined stereotactic radiosurgery and tyrosine kinase inhibitor therapy versus tyrosine kinase inhibitor therapy alone for the treatment of non-small cell lung cancer patients with brain metastases

OBJECTIVE

Whether combined radiation and tyrosine kinase inhibitor (TKI) therapy in non-small cell lung cancer (NSCLC) patients with brain metastases (BMs) and epidermal growth factor receptor (EGFR) mutations confers additional benefits over TKI therapy alone remains a matter of debate. The goal of this study was to compare outcomes between combined TKI therapy with stereotactic radiosurgery (SRS) versus TKI therapy alone in NSCLC patients with BMs and EGFR mutations.

METHODS

Consecutive cases of NSCLC patients with EGFR mutations and BMs treated with TKIs were selected for inclusion in this study. Patients were categorized into two groups based on SRS: TKI therapy alone (group I) and combined SRS and TKI therapy (group II). Patients who had SRS or TKI as salvage therapy and those with prior radiation treatment for BMs were excluded. Tumor control (< 10% increase in tumor volume) and overall survival (OS) rates were compared using Kaplan-Meier analyses. Independent predictors of tumor control and OS were identified using multivariable Cox regression analyses.

RESULTS

The study cohort comprised 280 patients (n = 90 in group I and n = 190 in group II). Cumulative tumor control rates were higher in group II than in group I (79.8% vs 31.2% at 36 months, p < 0.0001). Cumulative OS rates were comparable between groups I and II (43.8% vs 59.4% at 36 months, p = 0.3203). Independent predictors of tumor control were older age (p < 0.01, HR 1.03), fewer BMs (p < 0.01, HR 1.09), lack of extracranial metastasis (p < 0.02, HR 0.70), and combined SRS and TKI therapy (p < 0.01, HR 0.25). Independent predictors of OS were fewer BMs (p < 0.01, HR 1.04) and a higher Karnofsky Performance Status score (p < 0.01, HR 0.97).

CONCLUSIONS

Although the OS rate did not differ between TKI therapy with and without SRS, the addition of SRS to TKI therapy resulted in improvement of intracranial tumor control. The lack of effect on survival rate with the addition of SRS may be attributable to extracranial disease progression. The addition of SRS to TKI therapy is recommended for intracranial disease control in NSCLC patients with BMs and EGFR mutations. Potential benefits may include prevention of neurological deficits and seizures. Future prospective studies may help clarify the clinical outcome benefits of SRS in these patients.

Blood-Brain Barrier Permeability in Patients With Reversible Cerebral Vasoconstriction Syndrome Assessed With Dynamic Contrast-Enhanced MRI

BACKGROUND AND OBJECTIVES

Blood-brain barrier (BBB) disruption has been proposed to be important in the pathogenesis of reversible cerebral vasoconstriction syndrome (RCVS), but not all patients present an identifiable macroscopic BBB disruption; that is, visible contrast leakage on contrast-enhanced T2 fluid-attenuated inversion recovery imaging. This study aimed to evaluate microscopic BBB permeability and its dynamic change in patients with RCVS.

METHODS

This prospective cohort implemented 3T dynamic contrast-enhanced MRI. We measured microscopic BBB permeability by determining the whole-brain and white matter hyperintensity (WMH) K^trans values and evaluated the correlation of whole-brain K^trans permeability with clinical and vascular measures in transcranial color-coded sonography.

RESULTS

In total, 176 patients (363 scans) were analyzed and separated into acute (≦30 days) and remission (≧90 days) groups based on the onset-to-examination time. Whole-brain K^trans values were similar between patients with and without macroscopic BBB disruption in either acute or remission stage. The whole-brain K^trans was significantly decreased (p < 0.001) from acute to remission stages. The WMH K^trans was significantly higher than mirror references and decreased from acute to remission stages (p < 0.001). Whole-brain K^trans correlated with mean pulsatility index (r _s = 0.5, p = 0.029), mean resistance index (r _s = 0.662, p = 0.002), and distal-to-proximal ratio of resistance index (r _s = 0.801, p < 0.001) of M1 segment of middle cerebral arteries at around 10-15 days after onset. The time-trend curve of whole-brain K^trans depicted dynamic changes during disease course, similar to temporal trends of vasoconstrictions and WMH.

DISCUSSION

Patients with RCVS presented increased microscopic brain permeability during acute stage, even without discernible macroscopic BBB disruption. The dynamic changes in BBB permeability may be related to impaired cerebral microvascular compliance and WMH formation.

Estimating Pulsatile Blood Flow Parameters from Digital Subtraction Angiography

Digital subtraction angiography (DSA) is the gold standard for diagnosing vascular diseases. Much attention had been attracted on estimating blood flow velocity from DSA data, and many techniques to compute the mean flow velocity had been proposed. In this paper, we present a physical model that demonstrates how the pulsatile flow can affect the dispersion of the contrast medium delivered into the blood vessel. Using empirical mode decomposition and angiographic data of 4 patients, we then showed it is feasible to compute pulsatile flow related parameters from routine interventional angiographic acquisitions.Clinical Relevance- This is the first attempt to present a physical model and corresponding method to estimate pulsatile flow related parameters from routine angiographic acquisitions, and has potential to be used for real-time diagnostic and therapeutic monitoring during interventional procedures.

Quantification of tumor response of cystic vestibular schwannoma to Gamma Knife radiosurgery by using artificial intelligence

OBJECTIVE

Gamma Knife radiosurgery (GKRS) is a common treatment modality for vestibular schwannoma (VS). The ability to predict treatment response is important in patient counseling and decision-making. The authors developed an algorithm that can automatically segment and differentiate cystic and solid tumor components of VS. They also investigated associations between the quantified radiological features of each component and tumor response after GKRS.

METHODS

This is a retrospective study comprising 323 patients with VS treated with GKRS. After preprocessing and generation of pretreatment T2-weighted (T2W)/T1-weighted with contrast (T1WC) images, the authors segmented VSs into cystic and solid components by using fuzzy C-means clustering. Quantitative radiological features of the entire tumor and its cystic and solid components were extracted. Linear regression models were implemented to correlate clinical variables and radiological features with the specific growth rate (SGR) of VS after GKRS.

RESULTS

A multivariable linear regression model of radiological features of the entire tumor demonstrated that a higher tumor mean signal intensity (SI) on T2W/T1WC images (p < 0.001) was associated with a lower SGR after GKRS. Similarly, a multivariable linear regression model using radiological features of cystic and solid tumor components demonstrated that a higher solid component mean SI (p = 0.039) and a higher cystic component mean SI (p = 0.004) on T2W/T1WC images were associated with a lower SGR after GKRS. A larger cystic component proportion (p = 0.085) was associated with a trend toward a lower SGR after GKRS.

CONCLUSIONS

Radiological features of VSs on pretreatment MRI that were quantified using fuzzy C-means were associated with tumor response after GKRS. Tumors with a higher tumor mean SI, a higher solid component mean SI, and a higher cystic component mean SI on T2W/T1WC images were more likely to regress in volume after GKRS. Those with a larger cystic component proportion also trended toward regression after GKRS. Further refinement of the algorithm may allow direct prediction of tumor response.

Estimating blood flow velocity using time-resolved 3D angiography and a derived physical law of contrast media

OBJECTIVE

Four-dimensional (4D) digital subtraction angiography (DSA) offers a method for evaluating hemodynamics. It is, however, unclear how the delivered contrast medium interacts with the physiological blood flow, and how hemodynamic information may be inferred from the mixture of the contrast medium and blood. In this study, we present a theoretical explanation of contrast dynamics, and an accompanying algorithm for estimating blood flow velocity.

APPROACH

We retrospectively recruited 23 patients who underwent both 4D DSA and magnetic resonance (MR) phase-contrast imaging. The 4D DSA-reconstructed contrast dynamics were first studied for the internal carotid arteries. Using physical laws governing fluid motion within a curved tube, we showed that the reconstructed contrast dynamics obeyed a simple advection equation. We then proposed an algorithm for estimating the contrast dynamics using angiographic data, and subsequently estimated the axial blood flow velocity using an advection equation.

MAIN RESULTS

The estimated velocities were compared using three techniques: the Fourier technique, Lin's method, and MR phase contrast. Testing with noise-corrupted artificial data showed that the proposed algorithm was noise resistant. The velocities of 23 patients computed by 4D DSA using the proposed algorithm showed a moderate correlation with the MR phase contrast (r = 0.61), and good correlations with the other two techniques (r = 0.75 and r = 0.72).

SIGNIFICANCE

The proposed algorithm and has been applied to blood vessel segments with poor signal-to-noise ratios and axial lengths of less than 3 cm, and has a physical basis for computing axial flow velocities using an advection equation. The results of the proposed algorithm are consistent with existing methods.

Long-term cognitive and multimodal imaging outcomes after carotid artery stenting vs intensive medication alone for severe asymptomatic carotid stenosis

BACKGROUND

Severe carotid stenosis is associated with cognitive impairment, which may be attributed to asymptomatic microembolism and/or chronic hypoperfusion. We aim to evaluate the long-term cognitive and brain connectivity outcomes of carotid artery stenting (CAS) for asymptomatic ≥70% stenosis of the extracranial internal carotid artery (ICA).

METHODS

We conducted a non-randomized controlled study to compare intensive medical therapy alone (Med) or in combination with carotid artery stenting for the composite vascular events, neuropsychological, and multimodal magnetic resonance perfusion imaging and diffusion tensor imaging outcomes.

RESULTS

Sixty-nine patients were followed for a mean of 2.3 years (31 Med, 38 CAS) and 11 patients had composite vascular events of all-cause death, ischemic stroke, or myocardial infarction (6 Med vs 5 CAS). Forty-six asymptomatic subjects completed neuropsychological and multimodality imaging follow-ups (23 Med, 23 CAS). Compared to the Med group, the CAS group had a modest improvement of 12-item delayed verbal memory (8.9 ± 2.4 to 9.8 ± 2.7 vs 9.0 ± 2.1 to 8.9 ± 2.3, p = 0.04), but not in global cognition, attention or executive function, which was associated with increased structural connectivity of fractional anisotropy at the ipsilateral deep white matter. Importantly, the memory improvement was correlated with the perfusion increment at the ipsilateral middle cerebral artery territory.

CONCLUSION

For asymptomatic extracranial carotid steno-occlusion, successful carotid revascularization in addition to intensive medical treatment may potentially benefit cognitive reserve and connectivity strength which are partly attributed to restoration of non-critical hypoperfusion.

Quantitative CT angiography predicts large artery occlusion types and successful thrombectomy in acute ischemic stroke

BACKGROUND

Clinical and radiological outcomes of endovascular thrombectomy (EVT) are related to etiologies of large vessel occlusion (LVO) in acute stroke. However, preprocedural computed tomography angiography (CTA) or CT perfusion imaging can hardly distinguish embolic occlusion from atherosclerotic occlusion. We hypothesized that quantitative multiphase CTA (mCTA) of LVO may predict occlusion types and thrombectomy outcome.

METHODS

We retrospectively evaluated the consecutive stroke patients who had undergone mCTA and EVT <6 hours of onset at two independent medical centers. The intra-arterial radiodensities of Hounsfield unit (HU) were measured to examine the HUdistal/proximal ratio using receiver operating characteristic curve analysis. The derived cut-off value was re-examined in an independent cohort.

RESULTS

In the derivation cohort (n = 102), 81 patients (79.4%) were embolic occlusion without severe residual intracranial atherosclerotic stenosis (ICAS[-]) and 21 patients were atherosclerosis-related occlusion (ICAS[+]) based on digital subtraction angiography (DSA). The optimal cut-off to predict embolic occlusion was HU ratio <0.6 measured at 2 mm from the occlusion site (maximum area under the curve = 0.87; sensitivity 96%; specificity 81%). This cut-off also independently predicted successful recanalization using stent-retrievers and/or contact aspiration (modified Treatment in Cerebral Ischemia score ≥2b; p = 0.002) after adjusting for age, atrial fibrillation, and collateral circulation score, but not predicted favorable outcome at 3 months post stroke. Importantly, in the validation cohort (n = 95, 80% embolic occlusion), this HU ratio cut-off similarly predicted occlusion types and recanalization outcome, respectively.

CONCLUSION

The mCTA-based quantitative radiodensities of acute LVO provides preprocedural predictive values of DSA-determined occlusion types and thrombectomy outcomes.

Does the Diffuseness of the Nidus Affect the Outcome of Stereotactic Radiosurgery in Patients with Unruptured Cerebral Arteriovenous Malformations?

BACKGROUND

We proposed an algorithm to automate the components within the identification of components within the nidus of cerebral arteriovenous malformations (AVMs) which may be used to analyze the relationship between its diffuseness and treatment outcomes following stereotactic radiosurgery (SRS).

OBJECTIVES

to determine the impact of the diffuseness of the AVM nidus on SRS outcomes.

METHODS

This study conducted regular follow-ups of 209 patients with unruptured AVMs who underwent SRS. The diffuseness of the AVM nidus was estimated by quantifying the proportions of vascular nidal component, brain parenchyma, and cerebrospinal fluid in T2-weighted MRIs. We used Cox regression analysis to characterize the association between nidal diffuseness and treatment outcomes in terms of obliteration rate and radiation-induced change (RICs) rate following SRS.

RESULTS

The median AVM volume was 20.7 cm3. The median duration of imaging follow-up was 51 months after SRS. The overall AVM obliteration rate was 68.4%. RICs were identified in 156 of the 209 patients (74.6%). The median proportions of the nidus of AVM and brain parenchyma components within the prescription isodose range were 30.2 and 52.2%, respectively. Cox regression multivariate analysis revealed that the only factor associated with AVM obliteration rate after SRS was AVM volume. However, a larger AVM volume (>20 mL) and a larger proportion of brain parenchyma (>50%) within the prescription isodose range were both correlated with a higher RIC rate following SRS.

CONCLUSIONS

The diffuseness of the nidus indeed appears to affect the RIC rate following SRS in patients with unruptured AVMs.

Large Isospin Asymmetry in ^{22}Si/^{22}O Mirror Gamow-Teller Transitions Reveals the Halo Structure of ^{22}Al

β-delayed one-proton emissions of ^{22}Si, the lightest nucleus with an isospin projection T_{z}=-3, are studied with a silicon array surrounded by high-purity germanium detectors. Properties of β-decay branches and the reduced transition probabilities for the transitions to the low-lying states of ^{22}Al are determined. Compared to the mirror β decay of ^{22}O, the largest value of mirror asymmetry in low-lying states by far, with δ=209(96), is found in the transition to the first 1^{+} excited state. Shell-model calculation with isospin-nonconserving forces, including the T=1, J=2, 3 interaction related to the s_{1/2} orbit that introduces explicitly the isospin-symmetry breaking force and describes the loosely bound nature of the wave functions of the s_{1/2} orbit, can reproduce the observed data well and consistently explain the observation that a large δ value occurs for the first but not for the second 1^{+} excited state of ^{22}Al. Our results, while supporting the proton-halo structure in ^{22}Al, might provide another means to identify halo nuclei.

Premature Atrial Contractions and Their Association with Stroke Features and Outcome

BACKGROUND

Frequent premature atrial contractions (PACs) are associated with atrial fibrillation, stroke, and mortality. However, the cut-off value for PAC counts that could identify patients with different stroke features is unclear, and the association of PACs to outcome is not determined.

METHODS

The study retrospectively included patients with acute ischemic stroke who had underwent both a 24 h Holter recording and a brain MRI in Taipei Veterans General Hospital from January 2015 to May 2016. Patients were categorized into four groups according to their PAC frequencies on 24 h Holter recording. We compared the clinical severity, neuroimage features, stroke subtypes, and functional outcome among the four groups of patients.

RESULTS

Among the 278 patients, the lower, middle, and upper quartiles of the PAC counts were 23, 74, and 459.5, respectively. In contrast to the 1^st quartile of patients, the 3^rd (PAC 75-459/24 h) and the 4^th (PAC ≥460/24 h) quartiles of patients had higher NIH Stroke Scale (NIHSS) at admission (p = 0.014 and p = 0.002, respectively). The frequencies of cryptogenic stroke were not different among the 4 quartiles of the patients, but cryptogenic stroke patients with ≥ 75PACs/24hours had higher stroke severity compared to those with PACs < 75counts/24 h (NIHSS 9.1 vs. 5.2, p = 0.043). There was an increased trend in infarcts of multiple vascular territories and in mortality at 1 year among the four groups of patients with increased PAC frequency (p = 0.045 and p = 0.002, respectively). The 4^th PAC quartile was associated with poor functional outcome (modified Rankin Scale ≥ 4) at 3 months in univariate analysis (OR: 5.66, CI: 2.69-11.91, p < 0.001), but was not an independent predictor after controlling for initial stroke severity.

CONCLUSIONS

PACs ≥ 75 counts/24 h was associated with higher clinical severity in patients with acute ischemic stroke.

[The effects of vestibular rehabilitation training on the symptoms of vertigo and disability in patients with vestibular peripheral vertigo]

Objective: To compare the effects of vestibular rehabilitation training and drug therapy on the symptoms of vertigo and disability in patients with vestibular peripheral vertigo. Methods: This prospective study was enrolled 43 patients with vestibular peripheral vertigo who admitted to the outpatient department of Eye & ENT Hospital of Fudan University from January 2018 to December 2018. They were randomly divided into two groups: control group (drug treatment group) and experimental group (drug treatment combined rehabilitation training group). All patients filled in the first vertigo disability rating scale (DHI), specific activity balance confidence scale (ABC) and anxiety self-rating scale (SAS) on the day of treatment and at two, four and eight weeks after treatment intervention, and the data were statistically analyzed. Results: There was no significant difference in gender, age and body weight between the two groups (P>0.05). After treatment (Control group (4w) : DHI (45.5±30.6) , ABC (86.9±12.4) , SAS (37.9±8.2) Experimental group (8w) : DHI (34.8±28.5) , SAS (35.7±7.9) ) , the three scales of the two groups were better than before treatment (Control group: DHI (59.2±25.9) , ABC (79.7±16.7) ,SAS (41.1±6.8) ; Experimental group: DHI (55.2±20.5) , ABC (80.3±18.3) , SAS (41.9±9.1) ) . The comparison of data before and after treatment in each group according to treatment time indicated that DHI and ABC scores in the experimental group showed that the DHI and ABC scores of the experimental group changed significantly at 2 weeks after treatment, and the SAS scores changed at 4 weeks after treatment. The difference was statistically significant (P<0.05). However, there was a statistically significant difference between the control group DHI score 4 weeks after treatment and SAS score 8 weeks after treatment (P<0.05). ABC score did not show statistical difference (P>0.05). Conclusion: The subjective symptoms and anxiety of vertigo and disability in the two groups improved obviously after treatment. Compared with drug therapy alone, drug therapy combined with vestibular rehabilitation training can significantly improve patients' subjective symptoms of vertigo and disability, as well as their anxiety and depression, so as to improve their overall quality of life.

Improved Constraints on Sterile Neutrino Mixing from Disappearance Searches in the MINOS, MINOS+, Daya Bay, and Bugey-3 Experiments

Searches for electron antineutrino, muon neutrino, and muon antineutrino disappearance driven by sterile neutrino mixing have been carried out by the Daya Bay and MINOS+ collaborations. This Letter presents the combined results of these searches, along with exclusion results from the Bugey-3 reactor experiment, framed in a minimally extended four-neutrino scenario. Significantly improved constraints on the θ_{μe} mixing angle are derived that constitute the most constraining limits to date over five orders of magnitude in the mass-squared splitting Δm_{41}^{2}, excluding the 90% C.L. sterile-neutrino parameter space allowed by the LSND and MiniBooNE observations at 90% CL_{s} for Δm_{41}^{2}<13  eV^{2}. Furthermore, the LSND and MiniBooNE 99% C.L. allowed regions are excluded at 99% CL_{s} for Δm_{41}^{2}<1.6 eV^{2}.

Better endovascular mechanical thrombectomy outcome in atrial fibrillation patients with acute ischemic stroke: A single-center experience

BACKGROUND

Endovascular thrombectomy (EVT) has become the standard treatment for acute ischemic stroke with large vessel occlusion. Atrial fibrillation (AF) is one of the major causes. However, the impact of AF on the treatment has not yet been clearly discussed. This study is to evaluate the influence of AF on the outcomes of EVT in patients with acute ischemic stroke.

METHODS

Data from our Stroke Registry Database from April 2015 to July 2018 were reviewed. Technical efficacy, functional, and safety outcomes were reported and compared between patients with and without AF. A multivariate logistic regression model was performed to identify the predictors of the good functional outcome.

RESULTS

We reviewed 83 eligible patients receiving EVT. Patients (51.8%) were eventually found to have AF. The substantial reperfusion rate (modified thrombolysis in cerebral infarction 2b-3) was 72.1% and 55.0% in patients with and without AF, respectively, inclusive of a learning curve (p = 0.12). The good functional outcome (90-day modified Rankin scale: 0 to 2) rate was 55.8% and 17.5% in patients with and without AF, respectively (p < 0.01). A multivariable logistic regression analysis showed that age <70 years, the substantial reperfusion, and the presence of AF were three significant predictors for a good functional outcome.

CONCLUSION

Our study showed that patients with AF responded significantly better to EVT than those without AF did. Intracranial atherosclerotic diseases in patients without AF which were especially refractory to EVT may contribute to the difference of the functional outcomes between the two groups.

Repeated gamma knife radiosurgery enables longer tumor control in cases of highly-recurrent intracranial ependymoma

PURPOSE

Stereotactic radiosurgery (SRS) is a potential re-irradiation treatment for recurrent intracranial ependymoma after prior radiation therapy. The purpose of this study was to examine the efficacy and safety of repeated SRS in the treatment of recurrent intracranial ependymomas.

METHODS

This is a retrospective study of consecutive patients with residual or recurrent intracranial ependymomas who were treated with SRS between 1993 and 2018. Tumor progression was defined as a ≥ 10% increase in tumor volume. Tumor regression was defined as a ≥ 10% reduction in tumor volume. A tumor that remained within 10% of its original volume was defined as stable. Tumor control comprised tumor regression and stability. Time-dependent analyses were performed using two treatment failure endpoint definitions: (1) evidence of local tumor progression or distant metastasis (single SRS analysis), and (2) lack of tumor response to SRS (repeated SRS analysis). These analyses were adjusted for the competing risk of death.

RESULTS

The study comprised 37 patients (65 intracranial ependymomas) who underwent multiple SRS sessions (range: 1-7). Median age was 10.2 years (range: 0.8-53.8 years), and median tumor volume was 1.5 mL (range: 0.01-22.5 mL). The median radiation dose was 13.3 Gy (range: 7.9-22.0 Gy) at a median isodose line of 57% (range: 50-90%). Overall tumor control rates in the single SRS analysis adjusting for the competing risk of death were 53.6%, 30.5%, and 23.6% at 1, 3, and 5 years, respectively. Overall tumor control rates in the repeated SRS analysis adjusting for the competing risk of death were 70.6%, 50.4%, and 43.1% at 1, 3, and 5 years, respectively. Prior gross total resection was the only independent predictor of overall tumor control after SRS (aHR = 25.62 (1.55-422.1), p = 0.02).

CONCLUSIONS

Repeated GKRS appeared to be an effective treatment strategy for recurrent or residual intracranial ependymomas, with acceptable complication rates.

Single-phase computed tomography angiography sufficiently predicts outcomes after mechanical thrombectomy

BACKGROUND

Arterial collateral (AC) assessed by single-phase computed tomography angiography (CTA) or multiphase CTA has been used to predict clinical outcomes in patients undergoing mechanical thrombectomy (MT). Recently, venous opacification (VO) was proposed as another accurate image marker. This study aimed to compare the efficacy using AC and VO as predictors of MT outcome.

METHODS

Patients with occlusion of the proximal anterior circulation undergoing MT were included retrospectively. We assessed the AC status respectively according to different methods: modified Tan score, Miteff score in single-phase CTA, and pial arterial filling score in multiphase CTA. VO was assessed according to cortical vein opacification score. Favorable clinical outcome was defined as modified Rankin Scale 0-2 90 days after MT. Logistic regression models were established and receiver operating characteristics curve were used to determine the predictability of favorable outcome in patients with adequate AC and VO.

RESULTS

A total of 75 patients were enrolled. Adequate AC identified by modified Tan score (odds ratio, 7.3; p < 0.001), Miteff score (odds ratio, 4.5; p = 0.009), significantly predicted favorable outcome, but not adequate VO. The area under the curve was largest for adequate AC in model of modified Tan score 0.730 (95% CI, 0.60-0.86), while adequate VO showed the least area under the curve: 0.577 (95% CI, 0.43-0.73).

CONCLUSION

We considered adequate AC in single-phase CTA could be reliable enough as an imaging marker rather than adequate VO to predict favorable outcome after MT.

Trigeminal Nerve Atrophy Predicts Pain Recurrence After Gamma Knife Stereotactic Radiosurgery for Classical Trigeminal Neuralgia

BACKGROUND

Trigeminal nerve atrophy and neurovascular compression (NVC) are frequently observed in classical trigeminal neuralgia (CTN).

OBJECTIVE

To determine whether nerve characteristics contribute to Gamma Knife (Elekta AB, Stockholm, Sweden) surgery (GKS) outcomes in unilateral CTN without previous surgery.

METHODS

From 2006 to 2012, 67 patients with unilateral CTN without previous surgery received GKS with a maximal dose of 90 Gy delivered to the trigeminal nerve juxta brainstem. Two evaluators, blinded to the side of pain, analyzed the magnetic resonance images before GKS to obtain the parameters, including nerve cross-sectional area (CSA), vessel type of NVC, and site of NVC along the nerve. Correlations of the parameters with pain relief (Barrow Neurological Institute [BNI] grades I-IIIb) and recurrence (BNI grades VI-V) were made by using Cox regression and Kaplan-Meier analyses.

RESULTS

The median CSA of the symptomatic nerves was significantly smaller than that of the asymptomatic nerves (4.95 vs 5.9 mm2, P < .001). After adjustment for age and sex, larger nerve CSA was associated with lower initial pain relief (hazard ratio 0.81, P = .03) and lower pain recurrence after initial response (hazard ratio 0.58, P = .02). Patients with nerve atrophy (CSA of ≤ 4.4 mm2 after receiver operating characteristic curve analysis) had a lower 5-yr probability of maintaining pain relief after initial response than those without nerve atrophy (65% vs 86%, P = .04).

CONCLUSION

Trigeminal nerve atrophy may predict pain recurrence in patients with initial post-GKS relief of CTN. Arterial and proximal NVC are not predictive of GKS outcomes. Future studies are required to determine optimal treatments for long-term pain relief in patients with CTN and trigeminal nerve atrophy.

Procedure-Related Temporal Infarct After Retractorless Transsylvian Selective Amygdalohippocampectomy and Impact on 2-Year Epilepsy Outcome

BACKGROUND

Selective amygdalohippocampectomy (SAH) is designed to treat patients with mesial temporal lobe epilepsy (MTLE).

OBJECTIVE

To determine the volume and impact of temporal lobe infarction after retractorless transsylvian SAH (en bloc resection of the hippocampus) that have not been reported.

METHODS

A retrospective analysis of patients treated with retractorless transsylvian SAH. Infarctions were detected by magnetic resonance imaging (MRI) within the first week after the operation. Neuropsychological testing was performed preoperatively and 6 mo later. Seizure outcome was evaluated 2 yr after epilepsy surgery.

RESULTS

Between 2010 and 2014, a total of 30 patients were included in this study. Analysis of postoperative MRI showed the following: (1) mean removal volume of the hippocampus-parahippocampus was 5.72 cm3, and (2) mean volumes of temporal and insular infarctions were 1.71 and 0.25 cm3, respectively. Twenty-five patients (83.3%) were free of disabling seizures (Engel class I) at 2 yr of outcome. Neuropsychological testing revealed improvement in Perceptual Organization Index (P = .036) and verbal paired associates II (P = .014) after the operation. Neither infarction volume nor removal volume was related to epilepsy outcome in linear regression model.

CONCLUSION

Transsylvian SAH has comparable seizure outcomes but bears inherent risks of vasospasm/vascular injury. Immediate postoperative small infarction volume around resection cavity or along surgical corridor was noticed after retractorless transsylvian SAH, which did not cause neuropsychological deteriorations, in contrast to previous study with the use of self-sustaining rigid retraction system. Further study should be performed to compare procedure-related infarctions and their impacts on neuropsychological outcomes in different selective approaches.