bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Shi’ism on the Malay Muslims of Malaysia (Pengaruh Fahaman Shi‘Ah Ke Atas Orang Islam Di Malaysia)
Authors: M Amin W Mohd Azam
Published: January 2021

This article aims to make a preliminary and general observation on some of the influences of Shi’ism on the Malay Muslims in Malaysia since post Iranian revolution in 1979 onwards. This research emphasizes on the impact of the Iranian revolution in 1979 on the Malay Muslim society of Malaysia and the effort of some to develop the Shi’ite community in the Malay Sunnite majority. Cases in focus are in the field of education, social and politics. The researcher employed the qualitative method that includes textual analysis of the materials related to Shi’ism, interviews, and focus group discussions (FGD) with those who sympathize with the Shiite groups. Among the findings are the Malay sect of Shi’ism emerged officially after the Iranian Revolution in 1979. After the revolution, many Malay students were sent to pursue their studies at the Republic of Iran. This led to the formation of Malay Shi’ites organizations that went in line with the aspiration of the Iranian Revolution. It also to some extent influenced some of the social activities of Malay Muslims of Malaysia.
Keywords: Schism, Shi’ism, Sunnism, Malay, Islam.  
Abstrak
Artikel ini bertujuan membuat satu pemerhatian awal dan umum keatas orang-orang Melayu Islam di Malaysia pasca revolusi Iran pada tahun 1979 dan selepasnya. Kajian ini menekankan impak revolusi Iran 1979 ke atas masyarakat Melayu Islam di Malaysia dan usaha sebahagian mereka untuk membentuk komuniti Shi‘ah di dalam masyarakat Melayu yang majoritinya Sunni. Kes-kes yang dikaji adalah dalam bidang pendidikan, sosial dan politik. Para pengkaji menggunakan metod kualitatif termasuk analisa tekstual terhadap bahan-bahan yang berkaitan fahaman Shi‘ah, temubual dan perbincangan kumpulan berfokus (FGD) dengan kumpulan-kumpulan yang bersimpati dengan fahaman tersebut. Di antara penemuan-penemuan dari kajian ini adalah kum-pulan Melayu Shi’ah muncul secara rasmi selepas revolusi Iran 1979. Selepas revolusi itu, ramai pelajar-pelajar Melayu Sunni telah dihantar menyambung pengajian mereka di republik Iran. Hal yang demikian menjurus kepada pembentukan organisasi-organisasi yang selari dengan aspirasi revolusi Iran. Dalam beberapa aspek, ia juga mempengaruhi aktiviti-aktiviti sosial orang-orang Melayu Islam di Malaysia.
Kata Kunci: Skete, Shī‘ah, Sunni, Melayu, Islam.
GEOMETRİ İLE İLGİLİ ÖZ-YETERLİK ÖLÇEĞİNİN GEÇERLİK VE GÜVENİRLİK ÇALIŞMASI
Authors: BAŞ Fatih Furkan , KATRANCI Yasemin
Published: January 2021

Geometri, yaşamın her noktasında bulunmakta olup yaşadığımız dünyayı yer, şekil ve konum açısından incelememize ve anlamamıza olanak sağlar. Ancak matematik dolayısıyla da geometri, yaşantımızda önemli bir işleve sahipken, öğrenciler tarafından sevilmemekte ve öğrenciler geometriyi başarmada yetersiz kalmaktadırlar. Öğrencilerin bu başarılarını ise çeşitli bilişsel ve duyuşsal özelliklerin etkilediği bilinmekte, bu duyuşsal özelliklerinden bir tanesi de öz-yeterlik inancı olarak karşımıza çıkmaktadır. Bu bağlamda, bu çalışmada geometriye yönelik öz-yeterliği belirlemek için bir ölçeğin geliştirilmesi amaçlanmıştır. Bu amaçla çalışma tarama modelinde tasarlanmıştır. Çalışmaya katılacak öğrenciler elverişli örnekleme yöntemine göre belirlenmiştir. Bu yönteme göre çalışmaya 527 ortaokul öğrencisi dâhil olmuştur. Ölçeğin geçerlik çalışmaları kapsamında açımlayıcı faktör analizi gerçekleştirilmiştir. Sonuçta 18 madde ve üç faktörden meydana gelen bir ölçek ortaya konmuştur. Ortaya konan bu yapının sınanması amacıyla ise doğrulayıcı faktör analizi yapılmış ve ölçeğin X2/sd oranı 1.55 olarak elde edilmiştir. Bu oran açımlayıcı faktör analizi ile belirlenen yapının mükemmel uyum sergilediğini göstermiştir. Güvenirlik analizleri sonucunda ise hem ölçeğin tümünün hem de alt faktörlerinin yüksek güvenirliğe sahip olduğu belirlenmiştir. Sonuçta, öğrencilerin geometriye yönelik öz-yeterlikleri ölçmeye yarayan geçerli ve güvenilir bir ölçek geliştirilmiştir. Çalışma ortaokul öğrencileriyle yürütüldüğünden dolayı ölçek bu seviyede öğrenim gören öğrencilerin geometriye yönelik öz-yeterliklerinin belirlenmesinde uygundur. Ölçeğin ilkokul veya lise düzeyinde kullanımı için ilgili analizlerin tekrarlanması gerekmektedir.
SÜRDÜRÜLEBİLİR REKABET ÜSTÜNLÜĞÜNDE ENTELEKTÜEL SERMAYENİN ÖNEMİ: KAYNAK TABANLI BİR YAKLAŞIM
Authors: YILDIZ Deniz , GENÇ Kurtuluş Yılmaz
Published: January 2021

Günümüzde işletmeler için küreselleşmeyle genişleyen pazar sınırları, hızla değişen teknoloji, müşterilerin isteklerindeki çeşitliliğin geçmiş yıllara göre daha hızlı değişmesi ve ürün çeşitliliğinde artış, rekabet edilebilirliği oldukça zorlaşmıştır. İşletmeler böyle bir rekabet ortamında hayatlarını sürdürebilmek için hem iç çevresinde hem de dış çevresindeki unsurları iyi analiz edip uygun stratejiler geliştirmelidir. Bunun içinde öncelikle sahip olduğu varlık ve yeteneklerinin ne olduğunu bilmeli ve bunları en uygun şekilde yönetebilmelidir. Buda kaynak temelli yaklaşım stratejisini ortaya çıkarmaktadır. İşletmelerin en temel kaynağı ise, insan sermayesidir. Geçmişte büyük bir maliyet kalemi olarak görülen insan sermayesi, günümüzde önemini arttırarak, önemli bir rekabet aracı olmuştur.Bu çalışmada amaç; Ordu İl’indeki işletmelerde insan sermayesi, insan sermayesinin işletmeye özgü olması ve örgütsel performans ölçütü olarak rekabet üstünlüğüne ulaşma düzeyi arasındaki ilişkiler ve yine bu değişkenlerle demografik değişkenler arasındaki ilişkileri belirlemektir. Araştırmamızın evrenini Ordu İl’indeki işletmeler oluşturmaktadır. Bu nedenle değişik sektörlerdeki işletmelerden oluşan 33 işletme araştırmanın örneklemini oluşturmaktadır. Örneklem verileri IBM SPSS programı kullanılarak analiz edilmiştir.Çalışmanın sonucunda, insan sermayesi ile örgütsel performans arasında, istatistiksel olarak anlamlı ilişki olmadığı sonucuna varılmıştır. Başka önemli bulguya göre ise örgüte özgü insan sermayesinin nitelikleri daha üstün hale geldikçe örgütsel performans da yükselmektedir. Diğer bir ifadeyle, örgüte özgü insan sermayesi ile örgütsel performans arasında istatistiksel olarak anlamlı ve pozitif ilişki vardır.
OKUL ÖNCESİ ÖĞRETMENLERİNİN BİREYSELLEŞTİRİLMİŞ EĞİTİM PROGRAMI (BEP) YETERLİKLERİ: BİR KARMA YÖNTEM ÇALIŞMASI
Authors: YÜKSEL Begümhan , OĞUR Özgür , İŞBİLİR Ayşegül
Published: January 2021

Bu çalışmada, okul öncesi öğretmenlerinin Bireyselleştirilmiş Eğitim Programı’nın (BEP) hazırlanması ve uygulamasına ilişkin yeterliliklerinin belirlenmesi, anlaşılması ve yorumlanması amaçlanmaktadır. Karma araştırma yöntemi ile desenlenmiş betimsel bir çalışma olan bu araştırmanın nicel boyutunda 193, nitel boyutunda ise 11 öğretmen çalışma grubunu oluşturmuştur. Nicel boyutta veriler araştırmacılar tarafından hazırlanan demografik bilgi formu ve İlik ve Sarı (2018) tarafından geliştirilen “Öğretmenler için Bireyselleştirilmiş Eğitim Programı Yeterlik Ölçeği (ÖBEPYÖ)” ile toplanırken, nitel boyutta ise araştırmacılar tarafından hazırlanan “BEP Hazırlama ve Uygulama Yarı Yapılandırılmış Görüşme Soruları” ile toplanmıştır. Nicel boyutunda ÖBEPYÖ’nden elde edilen verilerin çözümlenmesinde aritmetik ortalama, standart sapma, yüzde değerlerine bakılmış, nitel boyutta ise okul öncesi öğretmenlerinin bireyselleştirilmiş eğitim programı yetkinlikleri ile ilgili belirlenen “BEP Hazırlık Öncesi Sürecini Açıklayabilme Yeterliliği, BEP Hazırlama Yeterliliği, BEP Sürecinde Aile Katımını Sağlayabilme Yeterliliği, BEP’in Uygulanması ve Değerlendirilmesi Yeterliliği ve BEP ile ilgili Genel Yeterlilik” temaları doğrultusunda katılımcılarla yapılan görüşmelerden elde edilen verilere betimsel analiz yapılarak alt temalar oluşturulmuştur. Araştırmadan nicel yöntem ile elde edilen bulgu sonuçlarına göre okul öncesi öğretmenlerinin BEP yeterliliklerinin orta düzeyde olduğu tespit edilmiştir. Araştırmanın nitel boyutunda ise okul öncesi öğretmenleri ile yapılan yarı yapılandırılmış görüşmeler sonucunda öğretmenlerin BEP hazırlanmasına ilişkin kısa ve uzun dönemli hedeflerin belirlenmesi ve BEP’in uygulama ve değerlendirme boyutlarında bilgi eksiklerinin olduğu belirlenmiştir.
İZMİR MENEMEN BÖLGESİ DOĞUM ÂDETLERİ
Authors: TULAN Azime
Published: January 2021

İnsan hayatının geçiş dönemleri, inanışlarla bunlara bağlı ritüeller eşliğinde gerçekleşmiştir. Bireysel ve toplumsal anlam ve işlevleri olan bu inanış ve uygulamalar, kültürün oluşumunda önemli bir yere sahiptir. Geçiş dönemi olarak doğum, evlilik ve ölüm gibi özel anlar, toplumca sürdüre gelen âdet ve törensel uygulamaları doğurmuştur. Bu uygulamaların yaşamın içindeki insan üzerinde çok büyük etkileri vardır. Sosyal varlık olan insan; çevresinden soyut davranamaz ve böylece kuşaktan kuşağa geçen inanış, ritüel, gelenekleri benimser, uygular ve etrafına da taşır. Geçiş döneminde yeni bir durumu yaşayan ve bu sürece uyum sağlama adına denge kurmaya çalışan birey bunun için birtakım inanış ve uygulamalar gerçekleştirir. Geçiş dönemlerinden biri olan doğum mucizevî bir durumdur. Ama doğum sadece bebek için değil anne için de zorlu bir uyum sürecini beraberinde getirir. Dolayısıyla yaşamın sürdürülürlüğüne dair en güzel kanıt olan doğum, geçiş dönemleri içerisinde başlangıcı ifade eder ve oldukça önemlidir. Doğum fiziksel-biyolojik bir olgu dışında kültürel-sosyal bir durumdur. Hayata dâhil edilen bebek dünyadaki ilk anından itibaren bakıma muhtaçtır, çaresiz ve güçsüzdür. Yaşama uygunluğu anneye bağlıdır. İşte bu süreçte anne ve bebeğin geçiş dönemini iyi atlamaları için inanış, uygulama ve ritüeller gerçekleştirilir. Bu sayede anne-bebek topluma dâhil olur.Bu çalışma, İzmir Menemen ilçesindeki insan hayatının başlangıcı olan doğum ile ilgili inanış ve uygulamaları tanımlamayı ve bu uygulamaları değerlendirmeyi amaçlamıştır. Çalışmada mevcut literatür dikkate alınarak belirlenen bölgelerde doğum ile ilgili merasimlere, uygulamalara bizzat iştirak edilmiş, gözlemler yapılmıştır. Ayrıca konuyla alakalı çeşitli inanışları tespit amacıyla da mülakat yöntemi kullanılmıştır.
Checklist of marine diatoms from the Turkish coastal waters with updated nomenclature
Authors: Kaleli Aydın , Akçaalan Reyhan
Published: January 2021

Marine diatom research in the coastal waters of Turkey started nearly two centuries ago. In the last decades, in-creasing numbers of contri-butions extended the knowledge of the marine phytoplankton. While sev-eral studies dedicated to planktonic forms and the checklists published con-cerning on the phytoplank-ton, relatively low numbers of benthic diatom studies were performed. Therefore, this is the first detailed list of the marine diatoms in-cluding both planktonic and benthic forms in Turkish coasts. This paper brings up the checklist of the past re-search referring to the au-thors in the last two centu-ries within the scope of the latest nomenclature. A total of 767 taxa (species, varie-ties and forms) belonging to 183 genera were listed. This study focussed into the study areas according to the reviewed literature and showed that many areas are yet to be investigated.
Anaerobic co-digestion of food waste, goat and chicken manure for sustainable biogas production
Authors: LOHANİ Sunil Prasad
Published: January 2021

Anaerobic digestion of food waste alone is not very stable due to its acidic nature and high biodegradability. Co-digestion of food waste with alkaline substrate such as chicken manure and goat manure could enhance process stability and biogas yield. In this study comparison of mono digestion of food waste with 8% total solid content at an ambient temperature and co-digestion of food waste, goat and chicken manure at ratio 5:2:3 and 2:1:1 with 8% total solid content at an ambient temperature in hilly region of Nepal were carried out. Biogas yield was highest with mixing ratio of 5:2:3 with the values of 109 ml/gVS followed by mixing ratio of 2:1:1 with the values of 80 ml/gVS. Mono digestion of food waste was not stable and broke down after two weeks of operation. Findings from this study suggests that co-digestion could be a suitable method for addressing the problem related to stability in a single substrate digestion in an ambient temperature condition. Moreover, mixing ratio of co-digestion substrates is important for improved biogas production. Co-digestion of food waste with goat and chicken manure could be a practical approach for sustainable clean energy production and waste management in context of Nepal.
An overview on the use of nanotechnology in the renewable energy field
Authors: KUMAŞ Kazım , AKYÜZ Ali Özhan
Published: January 2021

Nanotechnology is extremely important for efficient use, storage and production of energy. In this context, it is one of the main objectives to contribute to cleaner, sustainable, production by reducing energy use with raw materials. Thus, it is ensured to prevent waste from various sources and to develop environmentally friendly production systems that produce less waste. Nanotechnology in the field of renewable energy sources, which is thought to be a solution to global warming that disrupts the natural balance, is one of the popular topics of today's technology. In this study, information is given about the usage areas of nanotechnology and its applications in the field of energy.
Energy, environmental and enviroeconomic analysis of the use R134a/R1234yf (10/90) as replace to R134a in a vapor compression cooling system
Authors: YILDIRIM Ragıp , YILDIZ Abdullah
Published: January 2021

In this study, the use of R134a and R134a/R1234yf (10/90) refrigerants in a cooling system have been investigated theoretically. The energy, environmental and enviroeconomic analyzes of refrigerants have been performed for a cooling system. The energy performances of refrigerants have been made for different evaporator (between -10 oC and 5 oC) temperatures and a constant condenser (35 oC) temperature. The R134a/R1234yf (10/90) has a higher mass flow rate (26.50%) than R134a. Because R134a/R1234yf (10/90) has a lower refrigerating effect (evaporator enthalpy difference) than R134a. The R134a/R1234yf (10/90) has slightly higher compressor energy consumption (nearly 2.94%) than R134a, and so the COP of R134a has slightly (nearly 2.85%) higher than R134a/R1234yf (10/90). When compared to R134a, it is seen that the R134a/R1234yf (10/90) significantly reduces discharge temperature (about 16%). The environmental and enviroeconomic result values of R134a/R1234yf (10/90) are slightly higher than R134a. However, even the slight differences are significant to the evaluation of the environmental impact of refrigerants. It is seen that the wind energy source has the lowest environmental and enviroeconomic value and so the wind energy is the best environmentally friendly energy source according to the other energy sources.
Detecting chemicals with high yield in pyrolytic liquid of spirulina sp. microalgae via GC-MS
Authors: ÖZÇAKIR Gamze , KARADUMAN Ali
Published: January 2021

Pyrolysis of Spirulina sp. Microalgae was carried out in a semi-batch glass reactor system. Effect of temperature on the yields of pyrolytic products (gaseous, liquid and solid residue) and chemical composition of the liquid products were investigated. All experiments were performed in 25 mL/min nitrogen atmosphere with 15 g feedstock which was dry and powder form of Spirulina. Temperature was varied from 470 to 620 °C with 50 °C break by utilizing PID controller which was setted 10 °C/min heating rate. The aqueous phase and bio-oil (organic phase) of the liquid products were characterized by GC-MS. Maximum yields of bio-oil and aqueous phase were obtained approximately as 30 wt. % at 520 °C and as 20 wt. % at 470 °C. It was detected that bio-oil composed of aliphatic and cyclic hydrocarbons (such as toluene and heptadecane), oxygenated components (such as phenol, o-cresol and nonadecanol), nitrogenous components (such as hexadecaneamide and 3-Methyl-1H-indole). Unlike bio-oil, hydrocarbons like toluene, ethyl benzene, styrene and alkanes were not detected in aqueous phase.
Comparative exergy analysis of the cascade cooling system for alternative refrigerant couples
Authors: DİKMEN Erkan , ŞENCAN ŞAHİN Arzu
Published: January 2021

In this work, a comparative exergy analysis of cascade cooling system working with alternative refrigerant couples has been carried out. In study; R454C and R-744 as low temperature cycle (LTC) refrigerant and R1234ze, R1234yf and R717 as high temperature cycle (HTC) refrigerant were used. The refrigerants used in the study have zero ODP and low GWP values. Exergy analysis was carried out to investigate the effect to exergy efficiency of operation parameters in cascade cooling system. The exergy efficiency values of the cascade cooling system decreases with increasing evaporator temperature for all refrigerant couples. The exergy efficiency values of the cascade cooling system decreases with increasing the condenser temperature. Obtained results show that in all cases, the refrigerant couple R454C/R717 has the highest exergy efficiency.
Fracture energy comparison of aluminum and boron composites for fuel cell end plates
Authors: AVCU Adem
Published: January 2021

Fuel cells have become an attractive choice because they do not cause environmental and noise pollution. Additionally, they do not contain any moving parts and have higher efficiency than fossil fuels. Therefore, improving the capability of fuel cells helps to provide clean energy. Among fuel cells, the proton exchange membrane fuel cell (PEMFC) includes five main parts that are end plate, membrane, gas diffusion layer (GDL), catalyst layer (CL), bipolar flow plate (BFP). End plates hold PEMFC parts together securely. They should have high mechanical strength and low density properties. Therefore, the choice of materials for the PEMFC endplate is important. The calculated values of fracture energy show quantitatively how much energy must be placed in the sample to create the fracture surface. In this study, a finite element study was performed to understand the fracture behavior of cracks in the selected materials under different loading angles. The results revealed that the total fracture energy of aluminum was higher than boron-aluminum 50 and boron-aluminum 65 composites.
Experimental flow analysis of vertical axis turbine for power generation in open channel system
Authors: YANIKTEPE Bülent , ŞEKEROĞLU Ertuğrul , SÖYLER Mustafa , ÖZALP Coskun
Published: January 2021

In this experimental study, flow structure over a three bladed vertical axis Darrieus turbine is investigated experimentally for Reynold Number, Re=9000 in an open channel. Rigidity ratio (σ), angle of attack, optimum values of blade chord length (CL), turbine radius (R) and height of turbine blades (H) are used as approximately 1.1 and α=-2°, CL=5 cm, R=13.75 cm and H=20 cm, respectively. According to the values, ¼ scale model of a vertical axis Darrieus turbine has been used in order to perform experimental flow analysis. In experimental flow analysis, two different azimuth angles, θ=270° and θ=240° are used to examine the flow characteristics in the Particle İmage Velocimetry (PIV) experiments. As a result of the experiments, time averaged velocity vectors , averaged streamlines , and averaged vortex fields , are obtained and interpreted time averaged velocity vectors , averaged streamlines , and averaged vortex fields , changes with the turbine blade positions. As a result, it is seen that turbine azimuthal angle affetcs the flow structure and streamline focal points, positive and negative vortex are formed in the flow region behind the turbine. Only one focal point at θ=240° is occurred while two focal points and one stagnation point are occurred at the angle of θ=270°.
Relationship of Personality Characteristics with Organizational Commitment among Secondary School Teachers
Authors: Nazir Faiza , Rashid Khalid , Shahzadi Uzma
Published: January 2021

The study aimed to find out the relationship of personality characteristics with organizational commitment among secondary school teachers. The study was descriptive in nature, and survey approach was used. The study was delimited to Punjab province. All the secondary school teachers teaching secondary classes were the population. The sample comprised of 330 SSTs selected via random sampling technique. Two self-developed reliable questionnaires were appreciated and validated before data administration. The analysis was performed using descriptive and inferential statistics through SPSS version 21. The findings of the study indicated that there is a positive and significant relationship was found between personality characteristics and organizational commitment among secondary school teachers. It was also concluded that personality characteristics effects on organizational commitment. The study recommends that training and refresher courses may be arranged for secondary school teachers for flourishing personality characteristics.
The role of diffusion tensor imaging and tractography in the surgical management of brainstem gliomas
Authors: Xiao Xiong , Kong Lu , Pan Changcun , Zhang Peng , Chen Xin , Sun Tao , Wang Mingran , Qiao Hui , Wu Zhen , Zhang Junting , Zhang Liwei
Published: January 2021

OBJECTIVE

Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) have the ability to noninvasively visualize changes in white matter tracts, as well as their relationships with lesions and other structures. DTI/DTT has been increasingly used to improve the safety and results of surgical treatment for lesions in eloquent areas, such as brainstem cavernous malformations. This study aimed to investigate the application value of DTI/DTT in brainstem glioma surgery and to validate the spatial accuracy of reconstructed corticospinal tracts (CSTs).

METHODS

A retrospective analysis was performed on 54 patients with brainstem gliomas who had undergone surgery from January 2016 to December 2018 at Beijing Tiantan Hospital. All patients underwent preoperative DTI and tumor resection with the assistance of DTT-merged neuronavigation and electrophysiological monitoring. Preoperative conventional MRI and DTI data were collected, and the muscle strength and modified Rankin Scale (mRS) score before and after surgery were measured. The surgical plan was created with the assistance of DTI/DTT findings. The accuracy of DTI/DTT was validated by performing direct subcortical stimulation (DsCS) intraoperatively. Multiple linear regression was used to investigate the relationship between quantitative parameters of DTI/DTT (such as the CST score and tumor-to-CST distance [TCD]) and postoperative muscle strength and mRS scores.

RESULTS

Among the 54 patients, 6 had normal bilateral CSTs, 12 patients had unilateral CST impairments, and 36 had bilateral CSTs involved. The most common changes in the CSTs were deformation (n = 29), followed by deviation (n = 28) and interruption (n = 27). The surgical approach was changed in 18 cases (33.3%) after accounting for the DTI/DTT results. Among 55 CSTs on which DsCS was performed, 46 (83.6%) were validated as spatially accurate by DsCS. The CST score and TCD were significantly correlated with postoperative muscle strength (r = −0.395, p < 0.001, and r = 0.275, p = 0.004, respectively) and postoperative mRS score (r = 0.430, p = 0.001, and r = −0.329, p = 0.015, respectively). The CST score was independently linearly associated with postoperative muscle strength (t = −2.461, p = 0.016) and the postoperative mRS score (t = 2.052, p = 0.046).

CONCLUSIONS

DTI/DTT is a valuable tool in the surgical management of brainstem gliomas. With good accuracy, it can help optimize surgical planning, guide tumor resection, and predict the postoperative muscle strength and postoperative quality of life of patients.
Neurotoxicity of subarachnoid Gd-based contrast agent accumulation: a potential complication of intraoperative MRI?
Authors: Lauer Monika , Lauer Arne , You Se-Jong , Kluge Sara , Hattingen Elke , Harter Patrick N. , Senft Christian , Wagner Marlies , Voss Martin
Published: January 2021

OBJECTIVE

Intraoperative MRI with Gd-based contrast agent (GBCA) improves the extent of resection of contrast-enhancing brain tumors. Signal changes of CSF due to perioperative GBCA leakage in the subarachnoid space have been reported. However, although GBCA potentially exhibits neurotoxic effects, so far no associated complications have been described. In this case series, the authors report a single-center cohort of patients with subarachnoid GBCA extravasation after intraoperative MRI and discuss potential neurotoxic complications and potential ways of avoiding them.

METHODS

All patients with CSF signal increase on unenhanced T1-weighted and FLAIR images on postoperative MRI, who had previously undergone tumor resection with use of intraoperative MRI, were retrospectively included and compared with a control cohort. The control group was matched in age, tumor characteristics, and extent of resection; comparisons were made regarding postoperative seizures and ICU stay. A subgroup with initially diagnosed malignant glioma was additionally analyzed for potential delay of initiation of adjuvant treatment and overall survival.

RESULTS

Seven patients with postoperative GBCA accumulation in the subarachnoid space were identified; 5 presented with focal seizures and altered mental status postoperatively. Poor patient condition led to extended ICU stay and prolonged delay of the initiation of adjuvant treatment in patients with newly diagnosed malignant glioma. Overall survival was reduced compared to the matched control group.

CONCLUSIONS

The results suggest that there might be a risk of neurotoxic complications if GBCA that is intravenously applied during neurosurgery leaks into the subarachnoid space. Patients with highly vascularized tumors with intraoperative bleeding seem to be especially at risk for GBCA accumulation and neurotoxic complications. Therefore, awareness of the potential risk of complicating GBCA leakage is mandatory in the application of intraoperative GBCA.
Navigated ultrasound-based image guidance during resection of gliomas: practical utility in intraoperative decision-making and outcomes
Authors: Shetty Prakash , Yeole Ujwal , Singh Vikas , Moiyadi Aliasgar
Published: January 2021

OBJECTIVE

Intraoperative imaging is increasingly being used for resection control in diffuse gliomas, in which the extent of resection (EOR) is important. Intraoperative ultrasound (iUS) has emerged as a highly effective tool in this context. Navigated ultrasound (NUS) combines the benefits of real-time imaging with the benefits of navigation guidance. In this study, the authors investigated the use of NUS as an intraoperative adjunct for resection control in gliomas.

METHODS

The authors retrospectively analyzed 210 glioma patients who underwent surgery using NUS at their center. The analysis included intraoperative decision-making, diagnostic accuracy, and operative outcomes, particularly EOR and related factors influencing this.

RESULTS

US-defined gross-total resection (GTR) was achieved in 57.6% of patients. Intermediate resection control scans were evaluable in 115 instances. These prompted a change in the operative decision in 42.5% of cases (the majority being further resection of unanticipated residual tumor). Eventual MRI-defined GTR rates were similar (58.6%), although the concordance between US and MRI was 81% (170/210 cases). There were 21 false positives and 19 false negatives with NUS, resulting in a sensitivity of 78%, specificity of 83%, positive predictive value of 77%, and negative predictive value of 84%. A large proportion of patients (13/19 patients, 68%) with false-negative results eventually had near-total resections. Tumor resectability, delineation, enhancement pattern, eloquent location, and US image resolution significantly influenced the GTR rate, though only resectability and eloquent location were significant on multivariate analysis.

CONCLUSIONS

NUS is a useful intraoperative adjunct for resection control in gliomas, detecting unanticipated tumor residues and positively influencing the course of the resection, eventually leading to higher resection rates. Nevertheless, resection is determined by the innate resectability of the tumor and its relationship to eloquent location, reinforcing the need to combine iUS with functional mapping techniques to optimize resections.
Benefits of endoscope-assisted microsurgery in the management of pediatric brain tumors
Authors: El Beltagy Mohamed A. , Atteya Mostafa M. E.
Published: January 2021

OBJECTIVE

Microsurgical and endoscopic techniques are vastly utilized in brain tumor surgery. Combining both techniques in the same procedure has different forms and applications. The aim of this work was to discuss the usefulness and describe the technical benefits of endoscope-assisted microsurgery (EAMS) in treating pediatric brain tumors in various anatomical locations.

METHODS

The medical records of 106 children who had undergone EAMS for brain tumors at Children’s Cancer Hospital Egypt (CCHE-57357) between January 2009 and January 2017 were reviewed. The patients’ ages ranged from 1 to 16 years (mean age 7.5 years). Technical variations, difficulties, complications, strategies, and extent of resection were addressed according to anatomical location.

RESULTS

In general, EAMS enabled closer inspection of tumor extension and surrounding vital structures, especially in the hidden corners not appreciable by the microscope alone, such as tumors in the internal auditory canal and cerebellopontine angle contents in 14 cases, all of which were totally excised, and the undersurface of the optic apparatus in 65 craniopharyngiomas. Total excision was achievable in 51 of the 65 craniopharyngiomas; residual tumor was intentionally left behind under endoscopic guidance in the remaining 14 patients to ensure better hypothalamic function. Vision improved in 15 of 16 patients who initially presented with visual defects. Only 4 patients had new-onset postoperative endocrinopathies. For intraventricular tumors, EAMS allowed earlier recognition of tumor pedicle and, hence, earlier control of the blood supply of the tumor and safer total excision of 12 lateral ventricle, 6 pineal and third ventricle, and 9 fourth ventricle tumors. The tandem use of the endoscope and microscope enabled safer tumor dissections that were performed with more confidence in situations in which pure microscopic excision was either not achievable or less safe. Technical strategies, pitfalls, difficulties, and precautions were categorized and described per tumor location.

CONCLUSIONS

EAMS of pediatric brain tumors is a promising, user-friendly tool that complements microsurgery in the management of these complex lesions. The benefits of 2D endoscopy are added to the benefits of stereoscopic perception. EAMS is especially helpful during the removal of different complex pediatric brain tumors. Simultaneous or tandem endoscopic and microscopic approaches may have the potential for better functional outcomes through better visualization and preservation of vital structures in corners that are hidden from the microscope.
Intraoperative real-time near-infrared optical imaging for the identification of metastatic brain tumors via microscope and exoscope
Authors: Muto Jun , Mine Yutaka , Nakagawa Yu , Joko Masahiro , Kagami Hiroshi , Inaba Makoto , Hasegawa Mitsuhiro , Lee John Y. K. , Hirose Yuichi
Published: January 2021

OBJECTIVE

As chemotherapy and radiotherapy have developed, the role of a neurosurgeon in the treatment of metastatic brain tumors is gradually changing. Real-time intraoperative visualization of brain tumors by near-infrared spectroscopy (NIRS) is feasible. The authors aimed to perform real-time intraoperative visualization of the metastatic tumor in brain surgery using second-window indocyanine green (SWIG) with microscope and exoscope systems.

METHODS

Ten patients with intraparenchymal brain metastatic tumors were administered 5 mg/kg indocyanine green (ICG) 1 day before the surgery. In some patients, a microscope was used to help identify the metastases, whereas in the others, an exoscope was used.

RESULTS

NIRS with the exoscope and microscope revealed the tumor location from the brain surface and the tumor itself in all 10 patients. The NIR signal could be detected though the normal brain parenchyma up to 20 mm. While the mean signal-to-background ratio (SBR) from the brain surface was 1.82 ± 1.30, it was 3.35 ± 1.76 from the tumor. The SBR of the tumor (p = 0.030) and the ratio of Gd-enhanced T1 tumor signal to normal brain (T1BR) (p = 0.0040) were significantly correlated with the tumor diameter. The SBR of the tumor was also correlated with the T1BR (p = 0.0020). The tumor was completely removed in 9 of the 10 patients, as confirmed by postoperative Gd-enhanced MRI. This was concomitant with the absence of NIR fluorescence at the end of surgery.

CONCLUSIONS

SWIG reveals the metastatic tumor location from the brain surface with both the microscope and exoscope systems. The Gd-enhanced T1 tumor signal may predict the NIR signal of the metastatic tumor, thus facilitating tumor resection.
68Ga-DOTATOC-PET/CT–guided resection of a primary intraosseous meningioma: technical note
Authors: Guinto-Nishimura Gerardo Y. , Gómez-Amador Juan L. , Kerik-Rotenberg Nora , Uribe-Pacheco Rodrigo , Sangrador-Deitos Marcos V. , Martínez-Manrique José J.
Published: January 2021

Primary intraosseous meningiomas (PIMs) are rare tumors that present with a variable radiological appearance and a clinical behavior that is considerably different from that of intracranial meningiomas. Treatment of PIMs consists of complete resection, which may be difficult to achieve due to the lack of clear tumor margins on conventional imaging studies. PET/CT using 68Ga-DOTA–conjugated peptides has been used for the diagnosis and treatment planning of different types of meningiomas due to these tracers’ affinity to somatostatin receptors, which are found in most meningiomas. However, this imaging modality’s use as an intraoperative adjunct has not been reported for PIMs. In this technical note, the authors describe a [68Ga-DOTA0-Tyr3]octreotide (68Ga-DOTATOC)-PET/CT–guided resection of a PIM. In this case, the area of increased uptake in the 68Ga-DOTATOC-PET/CT study extended well beyond the tumor margins identified on MRI. The patient’s pathology report confirmed the presence of tumor cells within peripheral bone, which macroscopically appeared normal. The authors propose 68Ga-DOTATOC-PET/CT as a valuable adjunct in the surgical management of PIMs and offer a reasonable justification for its use based on current evidence. Its use for intraoperative image guidance may aid neurosurgeons in achieving a complete resection, thus minimizing the risk of recurrence of this complex pathological entity.
Intraoperative MRI–based elastic fusion for anatomically accurate tractography of the corticospinal tract: correlation with intraoperative neuromonitoring and clinical status
Authors: Ille Sebastian , Schroeder Axel , Wagner Arthur , Negwer Chiara , Kreiser Kornelia , Meyer Bernhard , Krieg Sandro M.
Published: January 2021

OBJECTIVE

Tractography is a useful technique that is standardly applied to visualize subcortical pathways. However, brain shift hampers tractography use during the course of surgery. While intraoperative MRI (ioMRI) has been shown to be beneficial for use in oncology, intraoperative tractography can rarely be performed due to scanner, protocol, or head clamp limitations. Elastic fusion (EF), however, enables adjustment for brain shift of preoperative imaging and even tractography based on intraoperative images. The authors tested the hypothesis that adjustment of tractography by ioMRI-based EF (IBEF) correlates with the results of intraoperative neuromonitoring (IONM) and clinical outcome and is therefore a reliable method.

METHODS

In 304 consecutive patients treated between June 2018 and March 2020, 8 patients, who made up the basic study cohort, showed an intraoperative loss of motor evoked potentials (MEPs) during motor-eloquent glioma resection for a subcortical lesion within the corticospinal tract (CST) as shown by ioMRI. The authors preoperatively visualized the CST using tractography. Also, IBEFs of pre- and intraoperative images were obtained and the location of the CST was compared in relation to a subcortical lesion. In 11 patients (8 patients with intraoperative loss of MEPs, one of whom also showed loss of MEPs on IBEF evaluation, plus 3 additional patients with loss of MEPs on IBEF evaluation), the authors examined the location of the CST by direct subcortical stimulation (DSCS). The authors defined the IONM results and the functional outcome data as ground truth for analysis.

RESULTS

The maximum mean ± SD correction was 8.8 ± 2.9 (range 3.8–12.0) mm for the whole brain and 5.3 ± 2.4 (range 1.2–8.7) mm for the CST. The CST was located within the lesion before IBEF in 3 cases and after IBEF in all cases (p = 0.0256). All patients with intraoperative loss of MEPs suffered from surgery-related permanent motor deficits. By approximation, the location of the CST after IBEF could be verified by DSCS in 4 cases.

CONCLUSIONS

The present study shows that tractography after IBEF accurately correlates with IONM and patient outcomes and thus demonstrates reliability in this initial study.
Applications of indocyanine green in brain tumor surgery: review of clinical evidence and emerging technologies
Authors: Teng Clare W. , Huang Vincent , Arguelles Gabriel R. , Zhou Cecilia , Cho Steve S. , Harmsen Stefan , Lee John Y. K.
Published: January 2021

Indocyanine green (ICG) is a water-soluble dye that was approved by the FDA for biomedical purposes in 1956. Initially used to measure cardiocirculatory and hepatic functions, ICG’s fluorescent properties in the near-infrared (NIR) spectrum soon led to its application in ophthalmic angiography. In the early 2000s, ICG was formally introduced in neurosurgery as an angiographic tool. In 2016, the authors’ group pioneered a novel technique with ICG named second-window ICG (SWIG), which involves infusion of a high dose of ICG (5.0 mg/kg) in patients 24 hours prior to surgery. To date, applications of SWIG have been reported in patients with high-grade gliomas, meningiomas, brain metastases, pituitary adenomas, craniopharyngiomas, chordomas, and pinealomas.

The applications of ICG have clearly expanded rapidly across different specialties since its initial development. As an NIR fluorophore, ICG has advantages over other FDA-approved fluorophores, all of which are currently in the visible-light spectrum, because of NIR fluorescence’s increased tissue penetration and decreased autofluorescence. Recently, interest in the latest applications of ICG in brain tumor surgery has grown beyond its role as an NIR fluorophore, extending into shortwave infrared imaging and integration into nanotechnology. This review aims to summarize reported clinical studies on ICG fluorescence–guided surgery of intracranial tumors, as well as to provide an overview of the literature on emerging technologies related to the utility of ICG in neuro-oncological surgeries, including the following aspects: 1) ICG fluorescence in the NIR-II window; 2) ICG for photoacoustic imaging; and 3) ICG nanoparticles for combined diagnostic imaging and therapy (theranostic) applications.
Evaluation of the precision of operative augmented reality compared to standard neuronavigation using a 3D-printed skull
Authors: Haemmerli Julien , Davidovic Alioucha , Meling Torstein R. , Chavaz Lara , Schaller Karl , Bijlenga Philippe
Published: January 2021

OBJECTIVE

Augmented reality (AR) in cranial surgery allows direct projection of preregistered overlaid images in real time on the microscope surgical field. In this study, the authors aimed to compare the precision of AR-assisted navigation and standard pointer-based neuronavigation (NV) by using a 3D-printed skull in surgical conditions.

METHODS

A commercial standardized 3D-printed skull was scanned, fused, and referenced with an MR image and a CT scan of a patient with a 2 × 2–mm right frontal sinus defect. The defect was identified, registered, and integrated into NV. The target was physically marked on the 3D-printed skull replicating the right frontal sinus defect. Twenty-six subjects participated, 25 of whom had no prior NV or AR experience and 1 with little AR experience. The subjects were briefly trained in how to use NV, AR, and AR recalibration tools. Participants were asked to do the following: 1) “target the center of the defect in the 3D-printed skull with a navigation pointer, assisted only by NV orientation,” and 2) “use the surgical microscope and AR to focus on the center of the projected object” under conventional surgical conditions. For the AR task, the number of recalibrations was recorded. Confidence regarding NV and AR precision were assessed prior to and after the experiment by using a 9-level Likert scale.

RESULTS

The median distance to target was statistically lower for AR than for NV (1 mm [Q1: 1 mm, Q3: 2 mm] vs 3 mm [Q1: 2 mm, Q3: 4 mm] [p < 0.001]). In the AR task, the median number of recalibrations was 4 (Q1: 4, Q3: 4.75). The number of recalibrations was significantly correlated with the precision (Spearman rho: −0.71, p < 0.05). The trust assessment after performing the experiment scored a median of 8 for AR and 5.5 for NV (p < 0.01).

CONCLUSIONS

This study shows for the first time the superiority of AR over NV in terms of precision. AR is easy to use. The number of recalibrations performed using reference structures increases the precision of the navigation. The confidence regarding precision increases with experience.
Video-assisted thoracoscopic image-guided spine surgery: evolution of 19 years of experience, from endoscopy to fully integrated 3D navigation
Authors: Hanna George , Kim Terrence T. , Uddin Syed-Abdullah , Ross Lindsey , Johnson J. Patrick
Published: January 2021

OBJECTIVE

The purpose of this study was to describe the evolution of thoracoscopic spine surgery from basic endoscopic procedures using fluoroscopy and anatomical localization through developmental iterations to the current technology use in which endoscopy and image-guided surgery are merged with intraoperative CT scanning.

METHODS

The authors provided detailed explanations of their thoracoscopic spine surgery techniques, beginning with their early-generation endoscopy with fluoroscopic localization, which was followed with point surface matching techniques and early image guidance. The authors supplanted this with the modern era of image guidance, thoracoscopic spine surgery, and seamless integration that has reached its current level of refinement.

RESULTS

A retrospective review of single-institution thoracoscopic procedures performed by the senior author over the course of 19 years yielded a total of 160 patients, including 73 women and 87 men. The mean patient age was 55 years, and the range included patients 16–94 years of age. There were no patients with worsened neurological function. One hundred sixteen patients underwent surgery for thoracic disc herniation, 18 for underlying neoplasms with spinal cord compression, 14 for osteomyelitis and discitis, 12 for thoracic deformity with neurological changes, and 8 for traumatic etiologies.

CONCLUSIONS

More than 19 years of experience has revealed the benefits of integrating thoracoscopic spine surgery with intraoperative CT scanning and image-guided surgery, including direct decompression without manipulation of neural elements, superior 3D spatial orientation, and localization of complex spinal anatomy. With the exponential growth of machine learning, robotics, artificial intelligence, and advances in imaging techniques and endoscopic imaging, there may be further refinements of this technique on the horizon.
Magnetic resonance imaging–based synthetic computed tomography of the lumbar spine for surgical planning: a clinical proof-of-concept
Authors: Staartjes Victor E. , Seevinck Peter R. , Vandertop W. Peter , van Stralen Marijn , Schröder Marc L.
Published: January 2021

OBJECTIVE

Computed tomography scanning of the lumbar spine incurs a radiation dose ranging from 3.5 mSv to 19.5 mSv as well as relevant costs and is commonly necessary for spinal neuronavigation. Mitigation of the need for treatment-planning CT scans in the presence of MRI facilitated by MRI-based synthetic CT (sCT) would revolutionize navigated lumbar spine surgery. The authors aim to demonstrate, as a proof of concept, the capability of deep learning–based generation of sCT scans from MRI of the lumbar spine in 3 cases and to evaluate the potential of sCT for surgical planning.

METHODS

Synthetic CT reconstructions were made using a prototype version of the “BoneMRI” software. This deep learning–based image synthesis method relies on a convolutional neural network trained on paired MRI-CT data. A specific but generally available 4-minute 3D radiofrequency-spoiled T1-weighted multiple gradient echo MRI sequence was supplemented to a 1.5T lumbar spine MRI acquisition protocol.

RESULTS

In the 3 presented cases, the prototype sCT method allowed voxel-wise radiodensity estimation from MRI, resulting in qualitatively adequate CT images of the lumbar spine based on visual inspection. Normal as well as pathological structures were reliably visualized. In the first case, in which a spiral CT scan was available as a control, a volume CT dose index (CTDIvol) of 12.9 mGy could thus have been avoided. Pedicle screw trajectories and screw thickness were estimable based on sCT findings.

CONCLUSIONS

The evaluated prototype BoneMRI method enables generation of sCT scans from MRI images with only minor changes in the acquisition protocol, with a potential to reduce workflow complexity, radiation exposure, and costs. The quality of the generated CT scans was adequate based on visual inspection and could potentially be used for surgical planning, intraoperative neuronavigation, or for diagnostic purposes in an adjunctive manner.
Transcondylar fossa approach for the large, high-flow, and diffuse arteriovenous malformation of the posterior fossa
Authors: Torihashi Koichi , Ogura Takafumi , Kadowaki Mitsutoshi , Sakamoto Makoto , Kurosaki Masamichi
Published: January 2021

Posterior fossa high-grade arteriovenous malformations (AVMs) are challenging diseases. This video presents the treatment of a patient with a diffuse, high-flow AVM of the posterior fossa on the tonsil and cerebellopontine angle (4 cm in diameter) and deep draining veins. The patient had an intraventricular and cerebellar hemorrhage. After conservative treatment, total resection of the AVM was performed with embolization and surgery. The authors resected the nidus after the endovascular embolization, on the same day. The postoperative course was uneventful, and the patient was discharged with almost full recovery.

The video can be found here: https://youtu.be/logCCn3uKUc
Microsurgical treatment of a posterior fossa arteriovenous malformation initially mistaken for a dural arteriovenous fistula: avoidance of near disaster
Authors: Howard Brian M. , Barrow Daniel L.
Published: January 2021

Many brain arteriovenous malformations (AVMs) derive dural blood supply, while 10%–15% of dural arteriovenous fistulas (dAVFs) have pial arterial input. To differentiate between the two is critical, as treatment of these entities is diametrically opposed. To treat dAVFs, the draining vein(s) is disconnected from feeding arteries, which portends hemorrhagic complications for AVMs. The authors present an operative video of a subtle cerebellar AVM initially treated as a dAVF by attempted embolization through dural vessels. The lesion was subsequently microsurgically extirpated. The authors show a comparison case of an AVM mistaken for a dAVF and transvenous embolization that resulted in a fatal hemorrhage.

The video can be found here: https://youtu.be/eDeiMrGoE0Q