Editorial
Gender differences in the human brain Per Hj Nakstad
Scientific documentation of gender differences in the brain and spinal cord has in the past been difficult to find. In the last decennium the development of magnetic resonance imaging (MRI) and positron emission tomography (PET) has changed this, and continuous increase in knowledge about this field is evolving (1–11). Scientists have, of course, been aware of the existence of complicated brain networks, but lacking the full understanding of how these networks function. Nowadays, combining different methods of imaging, data processing, statistics, and physics creates the possibility to describe and construct understandable brain networks, such as the brain metabolic network described in the study from Nanjing University, China by Yuxiao Hu et al. (12) in this issue of Acta Radiologica. They have used FDG-PET in a material consisting of 400 ethnic Chinese people, 200 women and 200 men. The present paper demonstrates the complexities of studies dealing with these methods in disclosing brain structures and functions. Data processing, statistical methods, mathematics, and physics often play an important role in achieving safe results in such scientific studies. For practical benefit of radiologists and others, hence one objective for this journal, the content of complex studies such as this by Hu et al. may be difficult to fully understand and to gain benefit from. However, as a radiological journal it is one of our obligations as well to present how combinations of new and older methods may increase knowledge in the medical profession, and in particular radiology. This paper opens up a delicate field: anatomical and structural differences between male and female. It might even be difficult for some of us to accept that the female brain topography in some respects is different from that of male brains. The authors show that in women some hubs in the brain have greater gray matter volume and cortical thickness than in men. A few brain regions show significant gender differences in nodal topological metrics. The authors use young individuals in their evaluation, but as pointed out by the authors, one can see many interesting study projects emerging from systematical comparisons between genders, among them changes in the topological parameters
Acta Radiologica 2015, Vol. 56(2) 131–132 ! The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0284185114562993 acr.sagepub.com
during aging (1). Some papers are published regarding gender differences in gray matter (2–7), but regarding the organization of brain networks relatively few papers are published (8–11). The combination of data processing, mathematics, et cetera with modern imaging methods such as MRI and PET opens up a great possibility for important research by colleagues working in the imaging field. The question raised by the authors is of high interest: Does the difference in the topological architecture represent underlying behavioral and cognitive differences between genders?
References 1. Micheloyannis S, Vourkas M, Tsirka V, et al. The influence of ageing on complex brain networks. Hum Brain Mapp 2009;30:200–208. 2. Gur RC, Turetsky BI, Matsui M, et al. Sex differences in brain gray and white matter in healthy young adults: correlations with cognitive performance. J Neurosci 1999;19: 4065–4072. 3. Allen JS, Damasio H, Grabowski TJ, et al. Sexual dimorphism and assymetrics in the gray-white composition of human cerebrum. Neuroimage 2003;18:880–894. 4. Im K, Lee JM, Lee J, et al. Gender difference analysis of cortical thickness in healthy young adults with surface based methods. Neuroimage 2006;31:31–38. 5. Choe Kh, Cheng Y, Chen IY. Sex-linked white matter microstructure of the social and analytic brain. Neuroimage 2011;54:725–733. 6. Chen X, Sachdev PS, Wen W, et al. Sex differences in regional grey matter in healthy individuals aged 44–48 years: a voxel–based morphometric study. Neurimage 2007;36:691–699. 7. Luders E, Narr Kl, Thompson PM, et al. Gender effects on cortical thickness and the influence of scaling. Hum Brain Mapp 2009;27:314–324.
Ulleva˚l Universitetssykehus, Oslo, Norway Corresponding author: Per Hjalmar Nakstad, Ulleva˚l Universitetssykehus, kirkevn 166, Nevroradiologisk avd, Oslo, 0407 Norway. Email: [email protected]; [email protected]
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8. Gong G, Rosa-Neto P, Carbonell F, et al. Age- and gender differences in the cortical anatomical network. J Neurosci 2009;29:15684–15693. 9. Yan C, Gong G, Wang J, et al. Sex-and brain size-related small-world structural cortical networks in young adults: a DTI tractography study. Cereb Cortex 2011;21: 449–458. 10. Watts DJ, Strogatz SH. Collective dynamics in smallworld networks. Nature 1998;393:440–442.
11. Rubinov M, Sporns O. Complex networks measures of brain connectivity: uses and interpretations. Neuroimage 2010;26:63–72. 12. Hu Y, Xu Q, Shen J, et al. Small-worldness and gender differences of large scale brain metabolic covariance networks in young adults: A FDG PET study of 400 subjects. Acta Radiol 2015;56:204–213.
Acta Radiologica 2015, Vol. 56(2) 132 ! The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0284185114563649 acr.sagepub.com
Notice
In the January issue of Acta Radiologica Open, a case of irreversible electroporation (IRE) of a tumor in the pancreatic head is presented (1). The IRE is a wellknown technique that can be used in the treatment of, for example, inoperable pancreatic cancer. In this case, the patient had a metallic stent in the bile duct, which is strictly regarded as an absolute contraindication in doing such procedures. This procedure was, nevertheless, performed at a private institution, and when the complications became obvious, the patient was transferred to a university clinic and treated, unfortunately, with a fatal outcome. As interventional radiologists, we all realize the importance of knowing when to do, or more importantly, when not to do/perform special procedures. Reporting treatment results are important; however, reports of treatment failures are equally important, and not at least to focus on indications and contraindications of doing interventional procedures. The present
article is a good example of the importance of reporting treatment failure and most importantly when not to perform certain kinds of procedures. The focus should be kept on strict information of indications/ contraindications and treatment successes/failures. It is the responsibility of the interventional radiologist to be updated on the results of every technique used in the diagnosis and treatment of our patients. I recommend this article for reading and learning.
Arnulf Skjennald Chief editor Reference 1. Ma˚nsson C, Nilsson A, Karlson BM. Severe complications with irreversible electroporation of the pancreas in the presence of a metallic stent: a warning of a procedure that never should be performed. Acta Radiol Short Reports 4. DOI: 10.1177/2047981614556409.
Downloaded from acr.sagepub.com at PURDUE UNIV LIBRARY TSS on May 26, 2015
Gender differences in the human brain Per Hj Nakstad
Scientific documentation of gender differences in the brain and spinal cord has in the past been difficult to find. In the last decennium the development of magnetic resonance imaging (MRI) and positron emission tomography (PET) has changed this, and continuous increase in knowledge about this field is evolving (1–11). Scientists have, of course, been aware of the existence of complicated brain networks, but lacking the full understanding of how these networks function. Nowadays, combining different methods of imaging, data processing, statistics, and physics creates the possibility to describe and construct understandable brain networks, such as the brain metabolic network described in the study from Nanjing University, China by Yuxiao Hu et al. (12) in this issue of Acta Radiologica. They have used FDG-PET in a material consisting of 400 ethnic Chinese people, 200 women and 200 men. The present paper demonstrates the complexities of studies dealing with these methods in disclosing brain structures and functions. Data processing, statistical methods, mathematics, and physics often play an important role in achieving safe results in such scientific studies. For practical benefit of radiologists and others, hence one objective for this journal, the content of complex studies such as this by Hu et al. may be difficult to fully understand and to gain benefit from. However, as a radiological journal it is one of our obligations as well to present how combinations of new and older methods may increase knowledge in the medical profession, and in particular radiology. This paper opens up a delicate field: anatomical and structural differences between male and female. It might even be difficult for some of us to accept that the female brain topography in some respects is different from that of male brains. The authors show that in women some hubs in the brain have greater gray matter volume and cortical thickness than in men. A few brain regions show significant gender differences in nodal topological metrics. The authors use young individuals in their evaluation, but as pointed out by the authors, one can see many interesting study projects emerging from systematical comparisons between genders, among them changes in the topological parameters
Acta Radiologica 2015, Vol. 56(2) 131–132 ! The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0284185114562993 acr.sagepub.com
during aging (1). Some papers are published regarding gender differences in gray matter (2–7), but regarding the organization of brain networks relatively few papers are published (8–11). The combination of data processing, mathematics, et cetera with modern imaging methods such as MRI and PET opens up a great possibility for important research by colleagues working in the imaging field. The question raised by the authors is of high interest: Does the difference in the topological architecture represent underlying behavioral and cognitive differences between genders?
References 1. Micheloyannis S, Vourkas M, Tsirka V, et al. The influence of ageing on complex brain networks. Hum Brain Mapp 2009;30:200–208. 2. Gur RC, Turetsky BI, Matsui M, et al. Sex differences in brain gray and white matter in healthy young adults: correlations with cognitive performance. J Neurosci 1999;19: 4065–4072. 3. Allen JS, Damasio H, Grabowski TJ, et al. Sexual dimorphism and assymetrics in the gray-white composition of human cerebrum. Neuroimage 2003;18:880–894. 4. Im K, Lee JM, Lee J, et al. Gender difference analysis of cortical thickness in healthy young adults with surface based methods. Neuroimage 2006;31:31–38. 5. Choe Kh, Cheng Y, Chen IY. Sex-linked white matter microstructure of the social and analytic brain. Neuroimage 2011;54:725–733. 6. Chen X, Sachdev PS, Wen W, et al. Sex differences in regional grey matter in healthy individuals aged 44–48 years: a voxel–based morphometric study. Neurimage 2007;36:691–699. 7. Luders E, Narr Kl, Thompson PM, et al. Gender effects on cortical thickness and the influence of scaling. Hum Brain Mapp 2009;27:314–324.
Ulleva˚l Universitetssykehus, Oslo, Norway Corresponding author: Per Hjalmar Nakstad, Ulleva˚l Universitetssykehus, kirkevn 166, Nevroradiologisk avd, Oslo, 0407 Norway. Email: [email protected]; [email protected]
Downloaded from acr.sagepub.com at PURDUE UNIV LIBRARY TSS on May 26, 2015
132
Acta Radiologica 56(2)
8. Gong G, Rosa-Neto P, Carbonell F, et al. Age- and gender differences in the cortical anatomical network. J Neurosci 2009;29:15684–15693. 9. Yan C, Gong G, Wang J, et al. Sex-and brain size-related small-world structural cortical networks in young adults: a DTI tractography study. Cereb Cortex 2011;21: 449–458. 10. Watts DJ, Strogatz SH. Collective dynamics in smallworld networks. Nature 1998;393:440–442.
11. Rubinov M, Sporns O. Complex networks measures of brain connectivity: uses and interpretations. Neuroimage 2010;26:63–72. 12. Hu Y, Xu Q, Shen J, et al. Small-worldness and gender differences of large scale brain metabolic covariance networks in young adults: A FDG PET study of 400 subjects. Acta Radiol 2015;56:204–213.
Acta Radiologica 2015, Vol. 56(2) 132 ! The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0284185114563649 acr.sagepub.com
Notice
In the January issue of Acta Radiologica Open, a case of irreversible electroporation (IRE) of a tumor in the pancreatic head is presented (1). The IRE is a wellknown technique that can be used in the treatment of, for example, inoperable pancreatic cancer. In this case, the patient had a metallic stent in the bile duct, which is strictly regarded as an absolute contraindication in doing such procedures. This procedure was, nevertheless, performed at a private institution, and when the complications became obvious, the patient was transferred to a university clinic and treated, unfortunately, with a fatal outcome. As interventional radiologists, we all realize the importance of knowing when to do, or more importantly, when not to do/perform special procedures. Reporting treatment results are important; however, reports of treatment failures are equally important, and not at least to focus on indications and contraindications of doing interventional procedures. The present
article is a good example of the importance of reporting treatment failure and most importantly when not to perform certain kinds of procedures. The focus should be kept on strict information of indications/ contraindications and treatment successes/failures. It is the responsibility of the interventional radiologist to be updated on the results of every technique used in the diagnosis and treatment of our patients. I recommend this article for reading and learning.
Arnulf Skjennald Chief editor Reference 1. Ma˚nsson C, Nilsson A, Karlson BM. Severe complications with irreversible electroporation of the pancreas in the presence of a metallic stent: a warning of a procedure that never should be performed. Acta Radiol Short Reports 4. DOI: 10.1177/2047981614556409.
Downloaded from acr.sagepub.com at PURDUE UNIV LIBRARY TSS on May 26, 2015
