Impaired Glymphatic and Meningeal Lymphatic Functions in Patients with Chronic Migraine

OBJECTIVE

This study was undertaken to investigate migraine glymphatic and meningeal lymphatic vessel (mLV) functions.

METHODS

Migraine patients and healthy controls (HCs) were prospectively recruited between 2020 and 2023. Diffusion tensor image analysis along the perivascular space (DTI-ALPS) index for glymphatics and dynamic contrast-enhanced magnetic resonance imaging parameters (time to peak [TTP]/enhancement integral [EI]/mean time to enhance [MTE]) for para-superior sagittal (paraSSS)-mLV or paratransverse sinus (paraTS)-mLV in episodic migraine (EM), chronic migraine (CM), and CM with and without medication-overuse headache (MOH) were analyzed. DTI-ALPS correlations with clinical parameters (migraine severity [numeric rating scale]/disability [Migraine Disability Assessment (MIDAS)]/bodily pain [Widespread Pain Index]/sleep quality [Pittsburgh Sleep Quality Index (PSQI)]) were examined.

RESULTS

In total, 175 subjects (112 migraine + 63 HCs) were investigated. DTI-ALPS values were lower in CM (median [interquartile range] = 0.64 [0.12]) than in EM (0.71 [0.13], p = 0.005) and HCs (0.71 [0.09], p = 0.004). CM with MOH (0.63 [0.07]) had lower DTI-ALPS values than CM without MOH (0.73 [0.12], p < 0.001). Furthermore, CM had longer TTP (paraSSS-mLV: 55.8 [12.9] vs 40.0 [7.6], p < 0.001; paraTS-mLV: 51.2 [8.1] vs 44.0 [3.3], p = 0.002), EI (paraSSS-mLV: 45.5 [42.0] vs 16.1 [9.2], p < 0.001), and MTE (paraSSS-mLV: 253.7 [6.7] vs 248.4 [13.8], p < 0.001; paraTS-mLV: 252.0 [6.2] vs 249.7 [1.2], p < 0.001) than EM patients. The MIDAS (p = 0.002) and PSQI (p = 0.002) were negatively correlated with DTI-ALPS index after Bonferroni corrections (p < q = 0.01).

INTERPRETATION

CM patients, particularly those with MOH, have glymphatic and meningeal lymphatic dysfunctions, which are highly clinically relevant and may implicate pathogenesis for migraine chronification. ANN NEUROL 2024;95:583-595.

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.

Dynamic changes in glymphatic function in reversible cerebral vasoconstriction syndrome

BACKGROUND

The pathophysiology of the reversible cerebral vasoconstriction syndrome (RCVS) remains enigmatic and the role of glymphatics in RCVS pathophysiology has not been evaluated. We aimed to investigate RCVS glymphatic dynamics and its clinical correlates.

METHODS

We prospectively evaluated the glymphatic function in RCVS patients, with RCVS subjects and healthy controls (HCs) recruited between August 2020 and November 2023, by calculating diffusion-tensor imaging along the perivascular space (DTI-ALPS) index under a 3-T MRI. Clinical and vascular (transcranial color-coded duplex sonography) investigations were conducted in RCVS subjects. RCVS participants were separated into acute (≤ 30 days) and remission (≥ 90 days) groups by disease onset to MRI interval. The time-trend, acute stage and longitudinal analyses of the DTI-ALPS index were conducted. Correlations between DTI-ALPS index and vascular and clinical parameters were performed. Bonferroni correction was applied to vascular investigations (q = 0.05/11).

RESULTS

A total of 138 RCVS patients (mean age, 46.8 years ± 11.8; 128 women) and 42 HCs (mean age, 46.0 years ± 4.5; 35 women) were evaluated. Acute RCVS demonstrated lower DTI-ALPS index than HCs (p < 0.001) and remission RCVS (p < 0.001). A continuously increasing DTI-ALPS trend after disease onset was demonstrated. The DTI-ALPS was lower when the internal carotid arteries resistance index and six-item Headache Impact test scores were higher. In contrast, during 50-100 days after disease onset, the DTI-ALPS index was higher when the middle cerebral artery flow velocity was higher.

CONCLUSIONS

Glymphatic function in patients with RCVS exhibited a unique dynamic evolution that was temporally coupled to different vascular indices and headache-related disabilities along the disease course. These findings may provide novel insights into the complex interactions between glymphatic transport, vasomotor control and pain modulation.

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.

Automated identification and quantification of metastatic brain tumors and perilesional edema based on a deep learning neural network

PURPOSE

This paper presents a deep learning model for use in the automated segmentation of metastatic brain tumors and associated perilesional edema.

METHODS

The model was trained using Gamma Knife surgical data (90 MRI sets from 46 patients), including the initial treatment plan and follow-up images (T1-weighted contrast-enhanced (T1cWI) and T2-weighted images (T2WI)) manually annotated by neurosurgeons to indicate the target tumor and edema regions. A mask region-based convolutional neural network was used to extract brain parenchyma, after which the DeepMedic 3D convolutional neural network was in the segmentation of tumors and edemas.

RESULTS

Five-fold cross-validation demonstrated the efficacy of the brain parenchyma extraction model, achieving a Dice similarity coefficient of 96.4%. The segmentation models used for metastatic tumors and brain edema achieved Dice similarity coefficients of 71.6% and 85.1%, respectively. This study also presents an intuitive graphical user interface to facilitate the use of these models in clinical analysis.

CONCLUSION

This paper introduces a deep learning model for the automated segmentation and quantification of brain metastatic tumors and perilesional edema trained using only T1cWI and T2WI. This technique could facilitate further research on metastatic tumors and perilesional edema as well as other intracranial lesions.

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.

Treatment and survival of patients with small cell lung cancer and brain metastasis

PURPOSE

To elucidate treatment patterns and their outcomes in patients with small cell lung cancer (SCLC) and brain metastasis (BM).

METHODS

In this retrospective study, patients with SCLC and BM were stratified by treatment modality into three groups: those treated with systemic therapy only, those treated with stereotactic radiosurgery (SRS) and systemic therapy, and those treated with whole-brain radiotherapy (WBRT) and systemic therapy. The primary outcomes were overall survival (OS) and time to central nervous system progression (TTCP).

RESULTS

The analysis included 149 patients. After BM diagnosis, 48 patients (32.2%) received systemic therapy alone, 33 received SRS with systemic therapy, and 68 received WBRT with systemic therapy. The median OS and TTCP were 7.2 months and 8.7 months, respectively. Patients receiving WBRT with systemic therapy exhibited better intracranial control, but not better OS, than did the other patients. Key prognostic factors affecting OS were age, BM lesion count, chemotherapy, and immunotherapy. Notably, the Eastern Cooperative Oncology Group performance status and BM lesion count significantly influenced intracranial control in patients treated with SRS and systemic therapy.

CONCLUSION

Although WBRT combined with systemic therapy offer better intracranial control in patients with SCLC and BM, this approach is not superior to the other approaches in terms of OS benefits. Emerging systemic therapies, such as immunotherapy, may be used as alternative or adjunctive treatments for specific patient populations. Further studies are warranted to refine treatment selection.

Disrupted Brain Functional Status in Patients with Reversible Cerebral Vasoconstriction Syndrome

OBJECTIVES

The aim of this study was to investigate the functional networks in subjects with reversible cerebral vasoconstriction syndrome (RCVS) using resting-state functional magnetic resonance imaging (rs-fMRI).

METHODS

We prospectively recruited patients with RCVS and healthy controls (HCs) between February 2017 and April 2021. The rs-fMRI data were analyzed using graph theory methods. We compared node-based global and regional topological metrics (Bundle 1) and network-based intranetwork and internetwork connectivity (Bundle 2) between RCVS patients and HCs. We also explored the associations of clinical and vascular (ie, the Lindegaard index, LI) parameters with significant rs-fMRI metrics.

RESULTS

A total of 104 RCVS patients and 93 HCs were included in the final analysis. We identified significantly decreased local efficiency of the left dorsal anterior insula (dAI; p = 0.0005) in RCVS patients within 30 days after disease onset as compared to HCs, which improved 1 month later. RCVS patients also had increased global efficiency (p = 0.009) and decreased average degree centrality (p = 0.045), clustering coefficient (p = 0.033), and assortativity values (p = 0.003) in node-based analysis. In addition, patients with RCVS had increased internetwork connectivity of the default mode network (DMN) with the salience (p = 0.027) and dorsal attention (p = 0.016) networks. Significant correlations between LI and regional local efficiency in left dAI (rs  = -0.418, p = 0.042) was demonstrated.

INTERPRETATION

The significantly lower local efficiency of the left dAI, suggestive of impaired central autonomic modulation, was negatively correlated with vasoconstriction severity, which is highly plausible for the pathogenesis of RCVS. ANN NEUROL 2023;94:772-784.

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.

Working from home: Changes in radiologist reporting behavior in response to the COVID-19 pandemic

BACKGROUND

Remote reporting is an important preventive measure against coronavirus disease 2019 (COVID-19) for radiology departments; it reduces the chance of cross-infections between coworkers. The purpose of this study was to evaluate how the preferred locations that radiologists filed reports from changed in response to COVID-19 by measuring the use of internal teleradiology workstations.

METHODS

Data were obtained from the radiological information system (RIS) database at our institution, which recorded the reporting workstation for each radiological examination. The reporting activities in 2021 were divided into computed radiography (CR) and computed tomography (CT)/magnetic resonance imaging (MRI) groups. The Wilcoxon signed-rank test was used to measure differences in the use of off-site workstations in prepandemic, midpandemic, and postpandemic periods.

RESULTS

There were statistically significant increases in the number of reports filed from off-site workstations for each attending physician from the prepandemic period to the midpandemic period in both the CR (15.1%-25.4%, p = 0.041) and CT/MRI (18.9%-28.7%, p = 0.006) groups. There was no significant difference noted between the prepandemic and postpandemic periods for either the CR (15.1% vs 18.4%, p = 0.727) or CT/MRI group (18.9% vs 23.3%, p = 0.236).

CONCLUSION

In response to the COVID-19 outbreak, radiologists used internal teleradiology to report CR and CT/MRI examinations significantly more frequently. In contrast to the predictions of previous studies, the use of internal teleradiology returned to baseline levels after the pandemic was under control.

Federated Learning: A Cross-Institutional Feasibility Study of Deep Learning Based Intracranial Tumor Delineation Framework for Stereotactic Radiosurgery

BACKGROUND

Deep learning-based segmentation algorithms usually required large or multi-institute data sets to improve the performance and ability of generalization. However, protecting patient privacy is a key concern in the multi-institutional studies when conventional centralized learning (CL) is used.

PURPOSE

To explores the feasibility of a proposed lesion delineation for stereotactic radiosurgery (SRS) scheme for federated learning (FL), which can solve decentralization and privacy protection concerns.

STUDY TYPE

Retrospective.

SUBJECTS

506 and 118 vestibular schwannoma patients aged 15-88 and 22-85 from two institutes, respectively; 1069 and 256 meningioma patients aged 12-91 and 23-85, respectively; 574 and 705 brain metastasis patients aged 26-92 and 28-89, respectively.

FIELD STRENGTH/SEQUENCE

1.5T, spin-echo, and gradient-echo [Correction added after first online publication on 21 August 2023. Field Strength has been changed to "1.5T" from "5T" in this sentence.].

ASSESSMENT

The proposed lesion delineation method was integrated into an FL framework, and CL models were established as the baseline. The effect of image standardization strategies was also explored. The dice coefficient was used to evaluate the segmentation between the predicted delineation and the ground truth, which was manual delineated by neurosurgeons and a neuroradiologist.

STATISTICAL TESTS

The paired t-test was applied to compare the mean for the evaluated dice scores (p < 0.05).

RESULTS

FL performed the comparable mean dice coefficient to CL for the testing set of Taipei Veterans General Hospital regardless of standardization and parameter; for the Taichung Veterans General Hospital data, CL significantly (p < 0.05) outperformed FL while using bi-parameter, but comparable results while using single-parameter. For the non-SRS data, FL achieved the comparable applicability to CL with mean dice 0.78 versus 0.78 (without standardization), and outperformed to the baseline models of two institutes.

DATA CONCLUSION

The proposed lesion delineation successfully implemented into an FL framework. The FL models were applicable on SRS data of each participating institute, and the FL exhibited comparable mean dice coefficient to CL on non-SRS dataset. Standardization strategies would be recommended when FL is used.

LEVEL OF EVIDENCE

4 TECHNICAL EFFICACY: Stage 1.

Simulation and evaluation of increased imaging service capacity at the MRI department using reduced coil-setting times

The wait times for patients from their appointments to receiving magnetic resonance imaging (MRI) are usually long. To reduce this wait time, the present study proposed that service time wastage could be reduced by adjusting MRI examination scheduling by prioritizing patients who require examinations involving the same type of coil. This approach can reduce patient wait times and thereby maximize MRI departments' service times. To simulate an MRI department's action workflow, 2,447 MRI examination logs containing the deidentified information of patients and radiation technologists from the MRI department of a medical center were used, and a hybrid simulation model that combined discrete-event and agent-based simulations was developed. The experiment was conducted in two stages. In the first stage, the service time was increased by adjusting the examination schedule and thereby reducing the number of coil changes. In the second stage, the maximum number of additional patients that could be examined daily was determined. The average number of coil changes per day for the four MRI scanners of the aforementioned medical center was reduced by approximately 27. Thus, the MRI department gained 97.17 min/d, which enabled them to examine three additional patients per month. Consequently, the net monthly income of the hospital increased from US$17,067 to US$30,196, and the patient wait times for MRI examinations requiring the use of flexible torso and head, shoulder, 8-inch head, and torso MRI coils were shortened by 6 d and 23 h, 2 d and 15 h, 2 d and 9 h, and 16 h, respectively. Adjusting MRI examination scheduling by prioritizing patients that require the use of the same coil could reduce the coil-setting time, increase the daily number of patients who are examined, increase the net income of the MRI department, and shorten patient wait times for MRI examinations. Minimizing the operating times of specific examinations to maximize the number of services provided per day does not require additional personnel or resources. The results of the experimental simulations can be used as a reference by radiology department managers designing scheduling rules for examination appointments.

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.

Recommendations for additional magnetic resonance imaging in abdominal computed tomography

BACKGROUND

Reporting the findings from radiologic images is an important method for radiologists to communicate with referring physicians. The purpose of this study was to evaluate the effectiveness of the recommendations for additional imaging (RAIs) after abdominal computed tomography (CT) studies for abdominal magnetic resonance (MR) imaging.

METHODS

The institutional review board approved this retrospective study, which includes data collected from the radiology information system (RIS) database of a tertiary medical referral center. Associations between abdominal CT and subsequent abdominal MR were recorded. The effectiveness of RAIs in an abdominal report was determined. The influence of the wording and the location of the RAIs were also analyzed.

RESULTS

The presence of RAIs in an abdominal CT report for an abdominal MR examination was more likely to result in a subsequent MR examination within 120 days (36.7% vs. 4.0%). RAIs were also associated with a reduction in the time interval between the CT and MR examinations (29.0 days vs. 39.0 days). The most effective recommendations included wording that advocated for further evaluation and were mentioned in both the context and conclusion of the report.

CONCLUSION

RAIs have a significant influence on clinical decisions. Radiologists should be aware of the power of RAIs and be prudent and conscientious when making recommendations in radiology reports.

Lesion delineation framework for vestibular schwannoma, meningioma and brain metastasis for gamma knife radiosurgery using stereotactic magnetic resonance images

BACKGROUND AND OBJECTIVE

GKRS is an effective treatment for smaller intracranial tumors with a high control rate and low risk of complications. Target delineation in medical MR images is essential in the planning of GKRS and follow-up. A deep learning-based algorithm can effectively segment the targets from medical images and has been widely explored. However, state-of-the-art deep learning-based target delineation uses fixed sizes, and the isotropic voxel size may not be suitable for stereotactic MR images which use different anisotropic voxel sizes and numbers of slices according to the lesion size and location for clinical GKRS planning. This study developed an automatic deep learning-based segmentation scheme for stereotactic MR images.

METHODS

We retrospectively collected stereotactic MR images from 506 patients with VS, 1,069 patients with meningioma and 574 patients with BM who had been treated using GKRS; the lesion contours and individual T1W+C and T2W MR images were extracted from the GammaPlan system. The three-dimensional patching-based training strategy and dual-pathway architecture were used to manage inconsistent FOVs and anisotropic voxel size. Furthermore, we used two-parametric MR image as training input to segment the regions with different image characteristics (e.g., cystic lesions) effectively.

RESULTS

Our results for VS and BM demonstrated that the model trained using two-parametric MR images significantly outperformed the model trained using single-parametric images with median Dice coefficients (0.91, 0.05 versus 0.90, 0.06, and 0.82, 0.23 versus 0.78, 0.34, respectively), whereas predicted delineations in meningiomas using the dual-pathway model were dominated by single-parametric images (median Dice coefficients 0.83, 0.17 versus 0.84, 0.22). Finally, we combined three data sets to train the models, achieving the comparable or even higher testing median Dice (VS: 0.91, 0.07; meningioma: 0.83, 0.22; BM: 0.84, 0.23) in three diseases while using two-parametric as input.

CONCLUSIONS

Our proposed deep learning-based tumor segmentation scheme was successfully applied to multiple types of intracranial tumor (VS, meningioma and BM) undergoing GKRS and for segmenting the tumor effectively from stereotactic MR image volumes for use in GKRS planning.

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.

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.

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.

[Research progress of the application of methacrylic anhydride gelatin hydrogel in wound repair]

Wound repair is a common clinical problem, which seriously affects the quality of life of patients and also brings a heavy burden to the society. Hydrogel-based multifunctional dressing has shown strong potential in the treatment of acute and chronic wounds. In addition to its good histocompatibility, cell adhesion, and biodegradability, methacrylic anhydride gelatin (GelMA) hydrogel has also attracted much attention due to its low cost, mild reaction conditions, adjustable physicochemical properties, and wide clinical applications. In this paper, the characteristics of GelMA hydrogel and its research progress in wound repair are introduced, and the future development of multifunctional GelMA hydrogel dressing for wound treatment is prospected.

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.

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.

[Effects of moderate dose rosuvastatin on carotid plaque in patients with diabetes mellitus evaluated by magnetic resonance imaging]

Objective: To observe the effect of lipid regulating therapy on carotid atherosclerotic plaque in diabetic patients. Methods: The REACH study, conducted between March 2009 and February 2012, enrolled asymptomatic patients with magnetic resonance imaging (MRI) confirmed carotid atherosclerotic plaque, who had never taken lipid-lowering drugs. Patients were treated with a moderate dose of rosuvastatin for 24 months. Blood lipid levels were measured and carotid MRI was performed at baseline, 3 and 24 months after treatment. The volume of carotid wall and lipid-rich necrotic core (LRNC) were measured by image analysis software. This study retrospectively analyzed patients in the REACH study. Patients were divided into diabetes group and non-diabetic group. The changes of blood lipid level and MRI parameters of carotid atherosclerotic plaque were compared between the two groups and their correlation was analyzed. Results: A total of 38 patients with carotid atherosclerotic plaque were included in this study, including 13 patients (34.2%) in the diabetic group and 25 patients (65.8%) in the non-diabetic group. Baseline parameters were comparable between the two groups, except higher HbA1c level in diabetes group (P<0.05). Compared with baseline, the total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) and triglyceride (TG) levels were significantly decreased at 3 and 24 months in both two groups (P<0.05). The change of high-density lipoprotein cholesterol (HDL-C) in diabetes group was not obvious, while it was significantly increased in non-diabetic group at 24 months ((1.38±0.33) mmol/l vs. (1.26±0.26) mmol/l, P<0.05). MRI results showed that the volume and percentage of LRNC remained unchanged at 3 months, slightly decreased at 24 months (64.86 (45.37, 134.56) mm³ vs. 75.76 (48.20, 115.64) mm³, P>0.05) and (15.84% (11.47%, 24.85%) vs. 16.95% (11.64%, 22.91%), P>0.05) in diabetic group. In non-diabetic group, the volume and percentage of LRNC were significantly decreased at 3 months (63.01 (44.25, 188.64) mm³ vs. 72.49 (51.91, 199.59) mm³, P<0.05) and (13.76% (8.81%, 27.64%) vs. 16.04% (11.18%, 27.05%), P<0.05) respectively. Both parameters further decreased to (55.63 (27.18, 179.40) mm³) and (12.71% (8.39%, 24.41%)) at 24 months (both P<0.05). Wall volume, lumen volume and percent wall volume (PWV) were not affected post therapy in both two groups(P>0.05). There were no correlations between the changes of plaque parameters including volume and percentage of LRNC, wall volume, lumen volume, PWV and the changes of blood lipid parameters (TC, LDL-C, HDL-C and TG) in 3 and 24 months (P>0.05). Conclusion: Lipid-lowering therapy possesses different effects on carotid atherosclerotic plaque in diabetic and non-diabetic patients, and the LRNC improvement is more significant in non-diabetic patients as compared to diabetic patients.

Neuronal intranuclear inclusion disease in patients with adult-onset non-vascular leukoencephalopathy

Neuronal intranuclear inclusion disease (NIID), caused by an expansion of GGC repeats in the 5'-untranslated region of NOTCH2NLC, is an important but underdiagnosed cause of adult-onset leukoencephalopathies. The present study aimed to investigate the prevalence, clinical spectrum, and brain MRI characteristics of NIID in adult-onset nonvascular leukoencephalopathies and assess the diagnostic performance of neuroimaging features. One hundred and sixty-one unrelated Taiwanese patients with genetically undetermined nonvascular leukoencephalopathies were screened for the NOTCH2NLC GGC repeat expansions using fragment analysis, repeat-primed PCR, southern blot analysis and/or nanopore sequencing with Cas9-mediated enrichment. Among them, 32 (19.9%) patients had an expanded NOTCH2NLC allele and diagnosed with NIID. We enrolled another two affected family members from one patient for further analysis. The size of the expanded NOTCH2NLC GGC repeats in the 34 patients ranged from 73 to 323 repeats. Skin biopsy from five patients all showed eosinophilic, p62-positive intranuclear inclusions in the sweat gland cells and dermal adipocytes. Among the 34 NIID patents presenting with nonvascular leukoencephalopathies, the median age at symptom onset was 61 years (range, 41-78 years) and the initial presentations included cognitive decline (44.1%; 15/34), acute encephalitis-like episodes (32.4%; 11/34), limb weakness (11.8%, 4/34), and parkinsonism (11.8%; 4/34). Cognitive decline (64.7%; 22/34) and acute encephalitis-like episodes (55.9%; 19/34) were also the most common overall manifestations. Two-thirds of the patients had either bladder dysfunction or visual disturbance. Comparing the brain MRI features between the NIID patients and individuals with other undetermined leukoencephalopathies, corticomedullary junction curvilinear lesion on diffusion weighted imaging (DWI) was the best biomarker to diagnose NIID with high specificity (98.4%) and sensitivity (88.2%). However, such DWI abnormality was absent in 11.8% of the NIID patients. When only fluid-attenuated inversion recovery images were available, presence of white matter hyperintensity lesions (WMH) either in paravermis or middle cerebellar peduncles also favored the diagnosis of NIID with a specificity of 85.3% and a sensitivity of 76.5%. Among the ten patients' MRI performed within 5 days of the onset of acute encephalitis-like episodes, five showed cortical DWI hyperintense lesions and two revealed focal brain edema. In conclusion, NIID accounts for 19.9% (32/161) of patients with adult-onset genetically undiagnosed nonvascular leukoencephalopathies in Taiwan. Half of the NIID patients ever developed encephalitis-like episodes with restricted diffusion in the cortical regions at the acute stage DWI. Corticomedullary junction hyperintense lesions, WMH in paravermis or middle cerebellar peduncles, bladder dysfunction and visual disturbance are useful hints to diagnose NIID.

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.

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.

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.

[Lymphoplasmacytic lymphoma: a clinicopathological and prognostic analysis of 27 cases]

Objective: To study the clinical manifestations, pathologic features, diagnosis and differential diagnosis, treatment and prognosis of lymphoplasmacytic lymphoma/Waldenström's macroglobulinemia (LPL/WM). Methods: Twenty-seven cases of LPL from January 2016 to December 2020 at Guangdong Provincial People's Hospital were collected. The clinical data, histomorphology, immunophenotype, MYD88 L265P mutation, treatment and prognosis were analyzed retrospectively. Results: There were 19 males and 8 female patients, with median age of 63 years. The most common initial symptoms were fatigue related to anemia. Bone marrow was involved in all cases, lymphadenopathy was seen in 11 cases and splenomegaly in 10 cases. Monoclonal IgM type protein was detected in 25 cases, meeting the diagnostic criteria of WM. Microscopically, bone marrow and lymph nodes were infiltrated by small lymphocytes, plasmacytoid lymphocytes or plasma cells. The cells expressed pan B-cell markers and showed immunoglobulin light chain restriction. There was no expression of CD5, and low expression of CD23 and CD10; Ki-67 index was usually low. The positive rate of MYD88 L265P mutation was 73.9% (17/23). Most of the patients were treated with rituximab combined with alkylating agents, nucleoside analogues or immunomodulators, and the few patients with relapse or progression were treated with Ibutinib. During the 3-168 months' follow-up period, recurrence or progression were seen in nine cases. Thrombocytopenia, elevated β2-microglobulin and high-risk group were associated with recurrence or progression of the disease (P<0.05). The overall survival (OS) and progression-free survival (PFS) of the high-risk patients were significantly lower than those of the low-medium risk patients (P<0.05). Conclusions: LPL/WM is an exclusive diagnosis; the detection of MYD88 L265P mutation has high diagnostic value, but it is not specific. These cases should be assessed comprehensively for their clinical manifestation, serum IgM protein level and immunophenotype. The overall prognosis of LPL/WM is good, but there are still a small number of high-risk patients with rapid progress, and so the symptomatic patients should be diagnosed accurately and treated in a timely manner.

[Obstructive sleep apnea and metabolic syndrome: an association study based on a large sample clinical database]

Objective: To investigate the prevalence and associated risk factors of metabolic syndrome (MS) in patients with obstructive sleep apnea (OSA). Methods: From July 2007 to June 2017, a total of 8 155 adult subjects, including 6 484 males and 1 671 females, aged 18-90 (43.13±12.28), body mass index 14.61~59.56 (25.59±3.98) kg/m²,who were admitted to the Department of Otorhinolaryngology head and Neck surgery of The Sixth People's Hospital affiliated to Shanghai Jiao Tong University, were retrospectively analyzed. All patients underwent polysomnography and biochemical tests. Subjects were divided into four groups (non-OSA, mild OSA, moderate OSA, and severe OSA) according to OSA severity. The prevalence of MS was expressed as percentage, and the correlation between OSA and MS and its characteristic pathophysiological indicators was evaluated by logistic regression model after adjusting for factors such as gender, age, BMI, neck circumference, hip circumference, smoking and alcohol consumption, and was expressed by odds ratio (OR). SPSS 25.0 software was used for statistical analysis. Results: The overall prevalence of MS was 43.6%, and that of non-/mild/moderate/severe OSA group was 18.6%, 30.4%, 43.8%, 57.1%.Logistic regression showed that patients with mild/moderate/severe OSA had an increased risk of MS compared with non-OSA patients, with adjusted OR values and confidence intervals of 1.27 (1.05-1.54), 1.84 (1.53-2.22), and 2.08 (1.76-2.46), respectively (P<0.01).In addition, indicators of OSA anoxic burden [oxygen drop index(T_oxygen=7.1), minimum blood oxygen(T_minimum=56.3), blood oxygen saturation below 90% cumulative time ratio (T_CT90=10.6) ]were closely associated with MS disease(P<0.01), but sleep fragmentation index (arousals index) was not significantly associated with MS disease. Conclusion: The risk of MS gradually increases with the severity of OSA, and the indicators reflecting OSA hypoxia burden are closely related to MS disease.

Treatment response, risk of relapse and clinical characteristics of Taiwanese patients with neuromyelitis optica spectrum disorder

BACKGROUND/PURPOSE

The long-term disease course and efficacy of maintenance therapies have rarely been investigated in Asian patients with neuromyelitis optica spectrum disorder (NMOSD).

METHODS

Medical records of patients fulfilling the 2015 International Consensus Diagnostic Criteria for NMOSD at three medical centers in Taiwan were systematically analyzed. Linear regression analysis was performed to investigate factors related to annualized relapse rate (ARR); survival analysis was used to estimate the relapse-free intervals among therapies.

RESULTS

A total of 557 relapses affecting 648 regions (202 optic neuritis, 352 acute myelitis, and 94 brain syndromes) in 204 patients were analyzed during a follow-up period of 69.5 months (range, 1-420). Up to 36.1% of myelitis-onset patients and 24.0% of optic neuritis-onset patients exhibited a limited form disease, defined as having one or more relapses confined to the same region. The median ARR was significantly lower in patients with limited form disease than those with relapses involving multiple regions (0.30 vs. 0.47, respectively). An older age at disease onset was associated with a lower ARR (p = 0.023). Kaplan-Meier analysis showed that the estimated time (months) to next relapse was longest in rituximab-treatment group (58.0 ± 13.2), followed by immunosuppressant (48.5 ± 4.8) or prednisone (29.6 ± 4.6) groups, and shortest in those without maintenance therapy (27.6 ± 4.2) (p = 8.1 × 10^-7).

CONCLUSION

Limited form disease and older age at disease onset are associated with a lower relapse rate in NMOSD. Compared to no maintenance therapy, rituximab and immunosuppressant significantly reduce the relapse risks.

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.

Ensemble classification and segmentation for intracranial metastatic tumors on MRI images based on 2D U-nets

The extraction of brain tumor tissues in 3D Brain Magnetic Resonance Imaging (MRI) plays an important role in diagnosis before the gamma knife radiosurgery (GKRS). In this article, the post-contrast T1 whole-brain MRI images had been collected by Taipei Veterans General Hospital (TVGH) and stored in DICOM format (dated from 1999 to 2018). The proposed method starts with the active contour model to get the region of interest (ROI) automatically and enhance the image contrast. The segmentation models are trained by MRI images with tumors to avoid imbalanced data problem under model construction. In order to achieve this objective, a two-step ensemble approach is used to establish such diagnosis, first, classify whether there is any tumor in the image, and second, segment the intracranial metastatic tumors by ensemble neural networks based on 2D U-Net architecture. The ensemble for classification and segmentation simultaneously also improves segmentation accuracy. The result of classification achieves a F1-measure of [Formula: see text], while the result of segmentation achieves an IoU of [Formula: see text] and a DICE score of [Formula: see text]. Significantly reduce the time for manual labeling from 30 min to 18 s per patient.

Can 3D artificial intelligence models outshine 2D ones in the detection of intracranial metastatic tumors on magnetic resonance images?

BACKGROUND

This study aimed to compare the prediction performance of two-dimensional (2D) and three-dimensional (3D) semantic segmentation models for intracranial metastatic tumors with a volume ≥ 0.3 mL.

METHODS

We used postcontrast T1 whole-brain magnetic resonance (MR), which was collected from Taipei Veterans General Hospital (TVGH). Also, the study was approved by the institutional review board (IRB) of TVGH. The 2D image segmentation model does not fully use the spatial information between neighboring slices, whereas the 3D segmentation model does. We treated the U-Net as the basic model for 2D and 3D architectures.

RESULTS

For the prediction of intracranial metastatic tumors, the area under the curve (AUC) of the 3D model was 87.6% and that of the 2D model was 81.5%.

CONCLUSION

Building a semantic segmentation model based on 3D deep convolutional neural networks might be crucial to achieve a high detection rate in clinical applications for intracranial metastatic tumors.

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.

P–570 Embryos originating from oocytes with smooth endoplasmic reticulum clusters have a lower euploidy rate via PGT-A testing using next-generation sequencing

Study question

Does the presence of smooth endoplasmic reticulum clusters (sERCs) in oocytes affect the human embryo ploidy?

Summary answer

The euploidy rate of embryos originating from sERCs + oocytes is lower

What is known already

While an expert panel strongly recommended that sERCs+ oocytes should not be inseminated, some normal healthy babies derived from sERCs+ oocytes have been reported. In previous studies have shown that declined fertilization rate and lower proportions of good quality embryos are found in oocytes showing sERCs. The updating findings of the molecular status of sERC+ oocytes elucidated the sERCs+ oocytes may have impaired chromosomal segregation ability. However, no study reveals the relation between sERCs and embryo ploidy.

Study design, size, duration

A retrospective study enrolled 129 preimplantation genetic testing (PGT) cycles from January 2017 to March 2020 at Chang Gung Memorial Hospital, Lonkou.

Participants/materials, setting, methods

ICSI fertilization rate, Day5 usable blastocyst rate (D5UBR), total usable blastocyst rate (TUBR), euploidy rate, mosaic rate, and aneuploidy rate are investigated between embryo originating from sERCs+ and sERCs- oocytes.

Main results and the role of chance

Although higher TBUR in blastocyst derived from sERCs+ oocytes than sERCs- group (73.7% vs. 62.5%) but accompanied lower euploidy rate (7% vs. 29%) and higher aneuploid rate (79% vs. 54%).

Limitations, reasons for caution

Limited sample size, need a large-scale study to confirm the conclusion. The live-birth rate per embryo transfer cycle was not included for analysis. As we did not perform polar body analysis, we cannot state for sure that embryonic aneuploidy was related to the oocyte.

Wider implications of the findings: This study demonstrates that embryos originating from sERCs+ oocytes have a lower euploidy rate.

Trial registration number

CMRPG3H0751

Stereotactic Radiosurgery for Atypical (World Health Organization II) and Anaplastic (World Health Organization III) Meningiomas: Results From a Multicenter, International Cohort Study

BACKGROUND

Atypical and anaplastic meningiomas have reduced progression-free/overall survival (PFS/OS) compared to benign meningiomas. Stereotactic radiosurgery (SRS) for atypical meningiomas (AMs) and anaplastic meningiomas (malignant meningiomas, MMs) has not been adequately described.

OBJECTIVE

To define clinical/radiographic outcomes for patients undergoing SRS for AM/MMs.

METHODS

An international, multicenter, retrospective cohort study was performed to define clinical/imaging outcomes for patients receiving SRS for AM/MMs. Tumor progression was assessed with response assessment in neuro-oncology (RANO) criteria. Factors associated with PFS/OS were assessed using Kaplan-Meier analysis and a Cox proportional hazards model.

RESULTS

A total of 271 patients received SRS for AMs (n = 233, 85.9%) or MMs (n = 38, 14.0%). Single-fraction SRS was most commonly employed (n = 264, 97.4%) with a mean target dose of 14.8 Gy. SRS was used as adjuvant treatment (n = 85, 31.4%), salvage therapy (n = 182, 67.2%), or primary therapy (1.5%). The 5-yr PFS/OS rate was 33.6% and 77.0%, respectively. Increasing age (hazard ratio (HR) = 1.01, P < .05) and a Ki-67 index > 15% (HR = 1.66, P < .03) negatively correlated with PFS. MMs (HR = 3.21, P < .05), increased age (HR = 1.04, P = .04), and reduced KPS (HR = 0.95, P = .04) were associated with shortened OS. Adjuvant versus salvage SRS did not impact PFS/OS. A shortened interval between surgery and SRS improved PFS for AMs (HR = 0.99, P = .02) on subgroup analysis. Radiation necrosis occurred in 34 (12.5%) patients. Five-year rates of repeat surgery/radiation were 33.8% and 60.4%, respectively.

CONCLUSION

AM/MMs remain challenging tumors to treat. Elevated proliferative indices are associated with tumor recurrence, while MMs have worse survival. SRS can control AM/MMs in the short term, but the 5-yr PFS rates are low, underscoring the need for improved treatment options for these patients.

Inhibitory effects of lactoferrin on pulmonary inflammatory processes induced by lipopolysaccharide by modulating the TLR4-related pathway

This study tested the ability of lactoferrin to modulate pulmonary inflammation. To construct in vitro and in vivo inflammatory lung models, cells from the human lung adenocarcinoma cell line (A549) were exposed to lipopolysaccharide (LPS, 1 µg/mL), and mice (CD-1) were intratracheally administered LPS [10 mg/kg of body weight (BW), tracheal lumen injection], respectively. The A549 cells were preincubated with lactoferrin (10 mg/mL), and the mice were intraperitoneally injected with lactoferrin (100 mg/kg of BW), followed by LPS treatment. The concentrations of proinflammatory cytokines (IL-1β and TNF-α) in culture medium of A549 cells and in bronchoalveolar lavage fluid of the mice were determined using enzyme-linked immunosorbent assays. The toll-like receptor 4-related pathway (TLR4/MyD88/IRAK1/TRAF6/NFκB) was determined at gene and protein expression levels in A549 cells and mouse lung tissue. Results showed that LPS treatment significantly elevated the concentrations of IL-1β and TNF-α in the A549 cell culture medium and in bronchoalveolar lavage fluid of the mice; it also elevated both the mRNA and protein expressions of TLR4 and the TLR4 downstream factors in A549 cells and mouse lung tissue. Nevertheless, lactoferrin apparently depressed the releases of IL-1β and TNF-α from A549 cells and lung tissues stimulated by LPS, and significantly suppressed the TLR4 signaling pathway. Lactoferrin also promoted the enhancement of miR-146a expression in A549 cells and mouse lung tissue. Moreover, 100°C heating for 3 min caused total loss of the previously listed bioactivity of lactoferrin. Collectively, we proved that lactoferrin intervened in LPS-induced inflammation in the pulmonary cell model and in the mouse model, through inhibiting the TLR4-related pathway.

Effects of stereotactic radiosurgery versus conventional radiotherapy on body mass index in patients with craniopharyngioma

OBJECTIVE

Hypothalamic obesity is common among patients with craniopharyngioma. This study examined whether precise stereotactic radiosurgery reduces the risk of hypothalamic obesity in cases of craniopharyngioma with expected long-term survival.

METHODS

This cohort study included 40 patients who had undergone Gamma Knife radiosurgery (GKRS; n = 22) or fractionated radiotherapy (FRT; n = 18) for residual or recurrent craniopharyngioma. Neurological presentations, tumor volume changes, and BMI values were meticulously reviewed. The median clinical follow-up durations were 9.7 years in the GKRS group and 10.8 years in the FRT group.

RESULTS

The median ages at the time of GKRS and FRT were 9.0 years and 10.0 years, respectively. The median margin dose of GKRS was 12.0 Gy (range 10.0-16.0 Gy), whereas the median dose of FRT was 50.40 Gy (range 44.1-56.3 Gy). Prior to GKRS or FRT, the median BMI values were 20.5 kg/m2 in the GKRS cohort and 20.0 kg/m2 in the FRT cohort. The median BMIs after radiation therapy at final follow-up were 21.0 kg/m2 and 24.0 kg/m2 for the GKRS and FRT cohorts, respectively. In the FRT cohort, BMI curves rapidly increased beyond the 85th percentile of the upper limit of the general population. BMI curves in the GKRS cohort increased more gradually, and many of the patients merged into the normal growth curve after adolescence. However, the observed difference was not statistically significant (p = 0.409).

CONCLUSIONS

The study compared the two adjuvant radiation modalities most commonly used for recurrent and residual craniopharyngioma. The authors' results revealed that precise radiosurgery dose planning can mediate the subsequent increase in BMI. There is every indication that meticulous GKRS treatment is an effective approach to treating craniopharyngioma while also reducing the risk of hypothalamic obesity.

Applying artificial intelligence to longitudinal imaging analysis of vestibular schwannoma following radiosurgery

Artificial intelligence (AI) has been applied with considerable success in the fields of radiology, pathology, and neurosurgery. It is expected that AI will soon be used to optimize strategies for the clinical management of patients based on intensive imaging follow-up. Our objective in this study was to establish an algorithm by which to automate the volumetric measurement of vestibular schwannoma (VS) using a series of parametric MR images following radiosurgery. Based on a sample of 861 consecutive patients who underwent Gamma Knife radiosurgery (GKRS) between 1993 and 2008, the proposed end-to-end deep-learning scheme with automated pre-processing pipeline was applied to a series of 1290 MR examinations (T1W+C, and T2W parametric MR images). All of which were performed under consistent imaging acquisition protocols. The relative volume difference (RVD) between AI-based volumetric measurements and clinical measurements performed by expert radiologists were + 1.74%, - 0.31%, - 0.44%, - 0.19%, - 0.01%, and + 0.26% at each follow-up time point, regardless of the state of the tumor (progressed, pseudo-progressed, or regressed). This study outlines an approach to the evaluation of treatment responses via novel volumetric measurement algorithm, and can be used longitudinally following GKRS for VS. The proposed deep learning AI scheme is applicable to longitudinal follow-up assessments following a variety of therapeutic interventions.

Treatment of WHO Grade 2 Meningiomas With Stereotactic Radiosurgery: Identification of an Optimal Group for SRS Using RPA

PURPOSE

This study assesses a large multi-institutional database to present the outcomes of World Health Organization grade 2 meningiomas treated with stereotactic radiosurgery (SRS). We also compare the 3-year progression-free survival (PFS) to that reported in the Radiation Therapy Oncology Group 0539 phase 2 cooperative group meningioma trial.

METHODS AND MATERIALS

From an international, multicenter group, data were collected for grade 2 meningioma patients treated with SRS for demonstrable tumor from 1994 to 2019. Statistical methods used included the Kaplan-Meier method, Cox proportional hazards analysis, and recursive partitioning analysis.

RESULTS

Two hundred thirty-three patients treated at 12 institutions were included. Patients presented at a median age of 60 years (range, 13-90), and many had at least 2 prior resections (30%) or radiation therapy (22%). Forty-eight percent of patients had prior gross total resection. At SRS, the median treatment volume was 6.1 cm³ (0.1-97.6). A median 15 Gy (10-30) was delivered to a median percent isodose of 50 (30-80), most commonly in 1 fraction (95%). A model was developed using recursive partitioning analysis, with one point attributed to age >50 years, treatment volume >11.5 cm³, and prior radiation therapy or multiple surgeries. The good-prognostic group (score, 0-1) had improved PFS (P < .005) and time to local failure (P < .005) relative to the poor-prognostic group (score, 2-3). Age >50 years (hazard ratio = 1.85 [95% confidence interval, 1.09-3.14]) and multiple prior surgeries (hazard ratio = 1.80 [1.09-2.99]) also portended reduced PFS in patients without prior radiation therapy. Two hundred eighteen of 233 patients in this study qualified for the high-risk group of Radiation Therapy Oncology Group 0539, and they demonstrated similar outcomes (3-year PFS: 53.9% vs 58.8%). The good-prognostic group of SRS patients demonstrated slightly improved outcomes (3-year PFS: 63.1% vs 58.8%).

CONCLUSIONS

SRS should be considered in carefully selected patients with atypical meningiomas. We suggest the use of our good-prognostic group to optimize patient selection, and we strongly encourage the initiation of a clinical trial to prospectively validate these 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.

Prediction of pseudoprogression and long-term outcome of vestibular schwannoma after Gamma Knife radiosurgery based on preradiosurgical MR radiomics

BACKGROUND AND PURPOSE

Gamma Knife radiosurgery (GKRS) is a safe and effective treatment modality with a long-term tumor control rate over 90% for vestibular schwannoma (VS). However, numerous tumors may undergo a transient pseudoprogression during 6-18 months after GKRS followed by a long-term volume reduction. The aim of this study is to determine whether the radiomics analysis based on preradiosurgical MRI data could predict the pseudoprogression and long-term outcome of VS after GKRS.

MATERIALS AND METHODS

A longitudinal dataset of patients with VS treated by single GKRS were retrospectively collected. Overall 336 patients with no previous craniotomy for tumor removal and a median of 65-month follow-up period after radiosurgery were finally included in this study. In total 1763 radiomic features were extracted from the multiparameteric MRI data before GKRS followed by the machine-learning classification.

RESULTS

We constructed a two-level machine-learning model to predict the long-term outcome and the occurrence of transient pseudoprogression after GKRS separately. The prediction of long-term outcome achieved an accuracy of 88.4% based on five radiomic features describing the variation of T2-weighted intensity and inhomogeneity of contrast enhancement in tumor. The prediction of transient pseudoprogression achieved an accuracy of 85.0% based on another five radiomic features associated with the inhomogeneous hypointensity pattern of contrast enhancement and the variation of T2-weighted intensity.

CONCLUSION

The proposed machine-learning model based on the preradiosurgical MR radiomics provides a potential to predict the pseudoprogression and long-term outcome of VS after GKRS, which can benefit the treatment strategy in clinical practice.

Noninvasive Characterization of Human Glymphatics and Meningeal Lymphatics in an in vivo Model of Blood-Brain Barrier Leakage

OBJECTIVE

To evaluate human glymphatics and meningeal lymphatics noninvasively.

METHODS

This prospective study implemented 3-dimensional (3D) isotropic contrast-enhanced T2 fluid-attenuated inversion recovery (CE-T2-FLAIR) imaging with a 3T magnetic resonance machine to study cerebral glymphatics and meningeal lymphatics in patients with reversible cerebral vasoconstriction syndrome (RCVS) with (n = 92) or without (n = 90) blood-brain barrier (BBB) disruption and a diseased control group with cluster headache (n = 35). The contrast agent gadobutrol (0.2mmol/kg [0.2ml/kg]) was administered intravenously in all study subjects.

RESULTS

In total, 217 patients (182 RCVS, 35 cluster headache) were analyzed and separated into 2 groups based on the presence or absence of visible gadolinium (Gd) leakage. Para-arterial tracer enrichment was clearly depicted in those with overt BBB disruption, while paravenous and parasinus meningeal contrast enrichment was evident in both groups. Paravenous and parasinus contrast enrichment remained in RCVS patients in the remission stage and in cluster headache patients, suggesting that these meningeal lymphatic channels were universal anatomical structures rather than being phase- or condition-specific. Additionally, we demonstrated nodular leptomeningeal enhancement in 32.3% of participants, which might represent potential lymphatic reservoirs. Four selected RCVS patients who received consecutive contrasted 3D isotropic FLAIR imaging after gadobutrol administration showed that the Gd persisted for at least 54 minutes and was completely cleared within 18 hours.

INTERPRETATION

This large-scale in vivo study successfully demonstrated the putative human para-arterial glymphatic transports and meningeal lymphatics by clear depiction of para-arterial, parasinus, and paravenous meningeal contrast enrichment using high-resolution 3D isotropic CE-T2-FLAIR imaging noninvasively; this technique may serve as a basis for further studies to delineate clinical relevance of glymphatic clearance. ANN NEUROL 2021;89:111-124.

[Method of dietary nutritional status assessment and its application in cohort study of nutritional epidemiology]

Minimizing the burden on study subjects and assessing the general dietary nutritional status as accurately as possible are the basis of a nutritional epidemiological cohort study in the general population. While introducing the main dietary nutrition assessment methods, this paper manly describes the basic contents and principles for the development of food frequency questionnaire, and briefly illustrates the problems and solutions for the development of area specific food frequency questionnaires by taking the example of Tianjin Chronic Low-grade Systemic Inflammation and Health (TCLSIH) cohort study. Finally, discusses preliminarily the necessity and possibility of developing a national food frequency questionnaire.

Combining analysis of multi-parametric MR images into a convolutional neural network: Precise target delineation for vestibular schwannoma treatment planning

Manual delineation of vestibular schwannoma (VS) by magnetic resonance (MR) imaging is required for diagnosis, radiosurgery dose planning, and follow-up tumor volume measurement. A rapid and objective automatic segmentation method is required, but problems have been encountered due to the low through-plane resolution of standard VS MR scan protocols and because some patients have non-homogeneous cystic areas within their tumors. In this study, we retrospectively collected multi-parametric MR images from 516 patients with VS; these were extracted from the Gamma Knife radiosurgery planning system and consisted of T1-weighted (T1W), T2-weighted (T2W), and T1W with contrast (T1W + C) images. We developed an end-to-end deep-learning-based method via an automatic preprocessing pipeline. A two-pathway U-Net model involving two sizes of convolution kernel (i.e., 3 × 3 × 1 and 1 × 1 × 3) was used to extract the in-plane and through-plane features of the anisotropic MR images. A single-pathway model that adopted the same architecture as the two-pathway model, but used a kernel size of 3 × 3 × 3, was also developed for comparison purposes. In addition, we used multi-parametric MR images with different image contrasts as the model training input in order to effectively segment tumors with solid as well as cystic parts. The results of the automatic segmentation demonstrated that (1) the two-pathway model outperformed single-pathway model in terms of dice scores (0.90 ± 0.05 versus 0.87 ± 0.07); both of them having been trained using the T1W, T1W + C and T2W anisotropic MR images, (2) the optimal single-parametric two-pathway model (dice score: 0.88 ± 0.06) was then trained using the T1W + C images, and (3) the two-pathway models trained using bi-parametric (T1W + C and T2W) and tri-parametric (T1W, T2W, and T1W + C) images outperformed the model trained using the single-parametric (T1W + C) images (dice scores: 0.89 ± 0.05 and 0.90 ± 0.05, respectively, larger than 0.88 ± 0.06) because it showed improved segmentation of the non-homogeneous parts of the tumors. The proposed two-pathway U-Net model outperformed the single-pathway U-Net model when segmenting VS using anisotropic MR images. The multi-parametric models effectively improved on the defective segmentation obtained using the single-parametric models by separating the non-homogeneous tumors into their solid and cystic parts.

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.