This document discusses the use of functional MRI (fMRI) in preoperative planning for brain tumor patients. fMRI can help assess the relationship between functionally eloquent brain regions and tumor location to minimize postoperative deficits. It describes different tasks used in fMRI like motor and language tasks. Validation studies show high sensitivity and specificity for motor mapping but more variable results for language mapping. The document also discusses limitations of fMRI like spatial uncertainty and tumor effects on BOLD signal. Overall, fMRI provides useful information to guide surgery when used appropriately with an understanding of its limitations.
Presentation1.pptx, diffusion tensor imaging of white matter tract in cerebra...Abdellah Nazeer
Diffusion tensor imaging (DTI) allows visualization of white matter tract architecture in vivo. DTI measures the directionality of water diffusion within tissue to determine fiber orientation on a voxel-by-voxel basis. The document discusses several DTI patterns seen in white matter tracts altered by brain tumors. Intact tracts displaced by a tumor may retain normal anisotropy and be identifiable on DTI maps. Edematous tracts have reduced anisotropy but maintain orientation. Infiltrated tracts have abnormal anisotropy and orientation. Completely destroyed tracts lose all anisotropic diffusion. DTI is useful for preoperative mapping of tumor location relative to white matter tracts.
In this presentation, i have explained different modalities available for radiological evaluation of cns tumors. How to approach to a radiographic image and how to approach to a patient of cns tumors radiologically.
MRI in evaluation of white matter diseases like multiple sclerosis, leukodystrophies, demyelination, dysmyelination, ADEM, leukoencephalopathies, van der knaap disease, ALD, MLD, Krabbes disease, Leighs disease, Vanishing white matter disease, Canavan disease, Alexander disease
1) Wilhelm Roentgen discovered X-rays in 1895 and Arthur Schiiller studied skull X-rays systematically, establishing neuroradiology. 2) Advances like ventriculography and cerebral angiography in the early 20th century allowed visualization of the brain. 3) Magnetic resonance imaging was developed in the 1940s-1980s and became the preferred method for evaluating brain tumors due to its superior soft tissue contrast compared to CT.
This document discusses the localization, characterization, and key imaging features of various spinal tumors. It covers both intradural and extradural tumors, including their location within or outside the spinal cord. Common tumor types discussed include ependymoma, astrocytoma, hemangioblastoma, and spinal cord metastases. Key distinguishing imaging features between tumor types are provided, such as differences in location, enhancement patterns, presence of cysts, and association with other findings.
This document discusses various tumors and lesions that can occur in the posterior fossa region of the brain. It provides CT and MRI images and descriptions of common tumors in this area, including medulloblastoma, ependymoma, choroid plexus papilloma, brain stem gliomas, gangliogliomas, pilocytic astrocytomas, hemangioblastomas, and metastases from other cancers. The document is intended as an imaging guide for physicians to identify and diagnose different infra-tentorial lesions and tumors based on scan findings.
Presentation1.pptx, diffusion tensor imaging of white matter tract in cerebra...Abdellah Nazeer
Diffusion tensor imaging (DTI) allows visualization of white matter tract architecture in vivo. DTI measures the directionality of water diffusion within tissue to determine fiber orientation on a voxel-by-voxel basis. The document discusses several DTI patterns seen in white matter tracts altered by brain tumors. Intact tracts displaced by a tumor may retain normal anisotropy and be identifiable on DTI maps. Edematous tracts have reduced anisotropy but maintain orientation. Infiltrated tracts have abnormal anisotropy and orientation. Completely destroyed tracts lose all anisotropic diffusion. DTI is useful for preoperative mapping of tumor location relative to white matter tracts.
In this presentation, i have explained different modalities available for radiological evaluation of cns tumors. How to approach to a radiographic image and how to approach to a patient of cns tumors radiologically.
MRI in evaluation of white matter diseases like multiple sclerosis, leukodystrophies, demyelination, dysmyelination, ADEM, leukoencephalopathies, van der knaap disease, ALD, MLD, Krabbes disease, Leighs disease, Vanishing white matter disease, Canavan disease, Alexander disease
1) Wilhelm Roentgen discovered X-rays in 1895 and Arthur Schiiller studied skull X-rays systematically, establishing neuroradiology. 2) Advances like ventriculography and cerebral angiography in the early 20th century allowed visualization of the brain. 3) Magnetic resonance imaging was developed in the 1940s-1980s and became the preferred method for evaluating brain tumors due to its superior soft tissue contrast compared to CT.
This document discusses the localization, characterization, and key imaging features of various spinal tumors. It covers both intradural and extradural tumors, including their location within or outside the spinal cord. Common tumor types discussed include ependymoma, astrocytoma, hemangioblastoma, and spinal cord metastases. Key distinguishing imaging features between tumor types are provided, such as differences in location, enhancement patterns, presence of cysts, and association with other findings.
This document discusses various tumors and lesions that can occur in the posterior fossa region of the brain. It provides CT and MRI images and descriptions of common tumors in this area, including medulloblastoma, ependymoma, choroid plexus papilloma, brain stem gliomas, gangliogliomas, pilocytic astrocytomas, hemangioblastomas, and metastases from other cancers. The document is intended as an imaging guide for physicians to identify and diagnose different infra-tentorial lesions and tumors based on scan findings.
The hippocampus is a curved structure in the medial temporal lobe that resembles a seahorse. It consists of two interlocking U-shaped structures - the hippocampus proper (Ammon's horn) and the dentate gyrus. The hippocampus has three parts - the head, body, and tail. The hippocampus lies medial to the temporal horn and is separated from the amygdala by the uncal recess. Magnetic resonance imaging, particularly coronal T1-weighted and T2-weighted sequences, best depicts the anatomy of the hippocampus.
Presentation1.pptx, radiological anatomy of the brain.Abdellah Nazeer
This document provides an overview of the radiological anatomy of the brain through computed tomography (CT) imaging. It describes the skull bones and sutures that form the cranial vault, as well as the three cranial fossae that house different brain structures. It also discusses the meningeal layers, including the falx cerebri and tentorium cerebelli, and cerebrospinal fluid spaces within the brain. Key structures like the pituitary fossa and ventricular system are identified. Understanding the normal CT anatomy of the brain provides important context for radiological interpretation.
Presentation1.pptx, diffusion weighted imaging in brain tumour.Abdellah Nazeer
Diffusion-weighted MRI is useful for evaluating brain tumors by providing information about tumor cellularity and distinguishing different types of tumors. It can help differentiate high-grade from low-grade gliomas, as high-grade tumors tend to have lower apparent diffusion coefficients due to restricted diffusion from increased cellularity. Diffusion-weighted MRI is also helpful for distinguishing brain abscesses from cystic or necrotic tumors, and for differentiating tumor types like arachnoid cysts from epidermoid tumors. It may also provide information about tumor histology in cases of brain metastases.
1. Magnetic resonance angiography (MRA) is a non-invasive imaging technique that uses magnetic resonance imaging to visualize blood vessels and evaluate vascular anatomy and blood flow without using ionizing radiation or iodinated contrast material.
2. There are different MRA techniques including time-of-flight MRA, phase contrast MRA, and contrast-enhanced MRA. Time-of-flight MRA relies on differences in flowing and stationary blood signal while phase contrast MRA assesses velocity and direction of flow. Contrast-enhanced MRA uses gadolinium contrast to improve vessel depiction.
3. MRA has various clinical applications for evaluating carotid and intracranial arterial stenosis, aneurysms,
MR spectroscopy is a non-invasive technique that uses MRI to measure brain chemistry. It provides information about metabolites like NAA, creatine, and choline to help characterize lesions and diseases. Single-voxel MRS is less advanced but faster, while multi-voxel MRS examines more areas but takes longer. MRS is an additive test that is interpreted along with conventional MRI images to aid diagnosis.
BASICS OF NEUROANATOMY & BRAIN TUMOR RADIOLOGYKanhu Charan
The document discusses the basics of neuroanatomy and common brain tumors. It provides information on various sulci and gyri in the brain and their importance. The key sulci and gyri discussed include the central sulcus, which separates the frontal and parietal lobes; the intraparietal sulcus, which separates the superior and inferior parietal lobules; and the calcarine sulcus, which separates the cuneus and lingual gyrus. Understanding the location and relationships of sulci and gyri is important for interpreting neuroimaging of the brain.
Superficial brain structures are drained by cortical veins and the superior sagittal sinus. Central brain structures drain into the deep venous system including the internal cerebral veins, vein of Galen, and straight sinus. The veins of Labbé and transverse sinuses drain the posterior temporal and inferior parietal lobes. MR venography and CT venography can assess the cerebral venous system, with each technique having advantages and disadvantages.
imaging in neurology - demyelinating diseasesNeurologyKota
This document discusses various demyelinating diseases that can be imaged in neurology. It provides images and descriptions of findings for multiple sclerosis, ADEM, NMO spectrum disorder, Susac syndrome, CLIPPERS, acute disseminated encephalomyelitis, acute hemorrhagic leukoencephalitis, acute necrotizing encephalopathy, and osmotic demyelination syndrome. It compares imaging features of MS and NMOSD that can help differentiate the two conditions. The document also discusses variants of MS like Marburg disease, Schilder disease, and Balo concentric sclerosis.
MRI is the gold standard for diagnosing multiple sclerosis (MS). It can detect focal demyelinating lesions appearing as hyperintense areas on T2-weighted MRI. Different MRI sequences like T1, T2, FLAIR, and gadolinium contrast help identify lesions at various stages. MS lesions typically occur in periventricular white matter, corpus callosum, brainstem, and spinal cord. Advanced MRI techniques like MTR, DTI, and MRS provide additional insights into MS pathology by detecting subtle tissue damage. MRI plays a key role in the diagnostic criteria for MS by demonstrating dissemination of lesions in space and time. It is also used as an outcome measure in clinical trials to monitor
Presentation1.pptx sellar and para sellar massesAbdellah Nazeer
The document provides information on imaging techniques and differential diagnosis for sellar and parasellar masses. CT and MRI techniques are described for imaging the sella turcica region with details on slice thickness, field of view, and contrast usage. An anatomic approach is outlined to analyze sellar masses which involves identifying the pituitary gland, lesion location and characteristics, and establishing a differential diagnosis. Common pathologies that can occur in the sella and surrounding structures are then described individually, including the pituitary gland, stalk, optic chiasm, hypothalamus, carotid artery, cavernous sinus, and meninges. Imaging examples of lesions such as pituitary adenomas, craniopharyngiomas, and meningi
1. Adrenal imaging uses modalities like ultrasound, CT, MRI, and nuclear medicine to evaluate the adrenal glands and detect abnormalities.
2. CT is often the first choice to evaluate adrenal diseases and can characterize adrenal masses using attenuation values, enhancement patterns, and lipid content analysis.
3. Benign adrenal lesions include adenomas, myelolipomas, cysts, infections, and hemorrhages. Adenomas are the most common and often appear well-defined and homogeneous with characteristic lipid content and enhancement patterns on CT and MRI.
This document summarizes how functional magnetic resonance imaging (fMRI) can be used to see what areas of the brain are active while thinking. It explains that fMRI detects changes in blood oxygenation levels to map neural activity in the brain. The document outlines how fMRI works, describing that oxygen-rich and oxygen-poor blood have different magnetic properties and fMRI can pinpoint greater brain activity by tracking increased blood flow. Potential uses of fMRI discussed include brain mapping, understanding emotions, marketing research, and using fMRI to potentially detect lies.
Meningiomas are the most common non-glial tumors of the central nervous system. They are typically benign, slow-growing tumors that appear as well-circumscribed masses attached to the dura on imaging. CT often shows hyperattenuation and enhancement, while MRI demonstrates isointensity to gray matter and enhancement. Typical features include calcification, hyperostosis, and dural tail sign. Atypical features like cysts, hemorrhage or edema are less common. Advanced MRI techniques may help differentiate aggressive from non-aggressive meningiomas. Differential diagnosis includes other dural-based lesions.
Meningiomas account for 15% of all intracranial tumors and originate from the dura or arachnoid membranes. They are most common in middle-aged adults and affect women twice as often as men. Meningiomas are typically benign, slow-growing tumors that indent the brain as they enlarge. On CT imaging, meningiomas appear well-circumscribed, homogeneous, and hyperdense, and may induce hyperostosis of adjacent bone. MRI often reveals a characteristic "dural tail" sign of enhancement. Other histologic variants include hemangiopericytomas, which have a narrow dural attachment and lobulated shape.
This document summarizes various pathologies that can present as pineal region masses. It describes signs and symptoms such as Parinaud syndrome, hydrocephalus, precocious puberty, and pineal apoplexy. It then discusses tumors of pineal parenchymal origin including pineocytoma, pineal parenchymal tumor of intermediate differentiation, and pineoblastoma. It also covers germ cell tumors, pineal cysts, astrocytoma, and meningioma that can occur in the pineal region. Imaging findings for each condition are provided with examples.
fMRI technology uses the nuclear magnetic resonance (NMR) phenomenon to form images of neural activity in the brain. It relies on the different magnetic properties of oxygenated and deoxygenated hemoglobin. When neurons are active in a region of the brain, blood flow to that region increases, altering the ratio of oxygenated to deoxygenated hemoglobin and causing a change in the MRI signal. Spatial encoding techniques allow fMRI to locate these signal changes within the brain and form a 3D image showing patterns of neural activity.
Presentation1.pptx. radiological imaging of epilepsy.Abdellah Nazeer
1) Hippocampal sclerosis, characterized by hippocampal atrophy and increased signal intensity on MRI, is the most common epileptogenic abnormality found after epilepsy surgery.
2) Malformations of cortical development, including focal cortical dysplasias and heterotopias, are also common epileptogenic lesions found in surgical series, especially in patients with childhood-onset seizures.
3) In addition to structural abnormalities, low-grade gliomas and hamartomas located near the cerebral cortex are also important causes of drug-resistant epilepsy that may require surgery.
Magnetic resonance spectroscopy (MRS) is a noninvasive imaging technique that measures metabolite levels in tissues. It works by detecting signals from atomic nuclei such as hydrogen placed in a strong magnetic field. MRS is useful for evaluating brain tumors, infections, demyelinating diseases, and neurodegenerative conditions. It provides diagnostic information by analyzing peak levels of metabolites including NAA, creatine, choline, and lactate. MRS can help distinguish tumors from other lesions, detect radiation necrosis, and monitor treatment response. It is also used to diagnose inborn errors of metabolism and mitochondrial disorders.
This document summarizes evidence from 27 trials involving over 10,000 participants on the safety and efficacy of clot-dissolving drugs (thrombolytics) such as alteplase for treating acute ischemic stroke. The trials compared thrombolytics administered intravenously or intra-arterially within 4.5 hours of stroke onset to placebo or no treatment. Thrombolytics were found to improve outcomes after stroke but also increase the risk of serious bleeding in the brain. While thrombolytics can restore blood flow and reduce brain damage if given promptly, the risks and benefits were shown to depend on the time since stroke onset.
These are slides for an introductory lecture on fMRI/MRI and analysis of fMRI data. The corresponding tutorial is available on my website kathiseidlrathkopf.com
This document provides an overview of fetal MRI as a diagnostic imaging technique. It includes:
- An introduction and foreword discussing the technical advances and clinical applications of fetal MRI.
- A table of contents outlining the various topics to be covered across 29 chapters, including normal and pathological anatomy and development of various fetal organs as assessed by MRI.
- Information about the editors and editorial board who are international experts in fetal MRI and medical imaging.
- A preface by the editor, Dr. Daniela Prayer, introducing the aims and scope of the book.
The hippocampus is a curved structure in the medial temporal lobe that resembles a seahorse. It consists of two interlocking U-shaped structures - the hippocampus proper (Ammon's horn) and the dentate gyrus. The hippocampus has three parts - the head, body, and tail. The hippocampus lies medial to the temporal horn and is separated from the amygdala by the uncal recess. Magnetic resonance imaging, particularly coronal T1-weighted and T2-weighted sequences, best depicts the anatomy of the hippocampus.
Presentation1.pptx, radiological anatomy of the brain.Abdellah Nazeer
This document provides an overview of the radiological anatomy of the brain through computed tomography (CT) imaging. It describes the skull bones and sutures that form the cranial vault, as well as the three cranial fossae that house different brain structures. It also discusses the meningeal layers, including the falx cerebri and tentorium cerebelli, and cerebrospinal fluid spaces within the brain. Key structures like the pituitary fossa and ventricular system are identified. Understanding the normal CT anatomy of the brain provides important context for radiological interpretation.
Presentation1.pptx, diffusion weighted imaging in brain tumour.Abdellah Nazeer
Diffusion-weighted MRI is useful for evaluating brain tumors by providing information about tumor cellularity and distinguishing different types of tumors. It can help differentiate high-grade from low-grade gliomas, as high-grade tumors tend to have lower apparent diffusion coefficients due to restricted diffusion from increased cellularity. Diffusion-weighted MRI is also helpful for distinguishing brain abscesses from cystic or necrotic tumors, and for differentiating tumor types like arachnoid cysts from epidermoid tumors. It may also provide information about tumor histology in cases of brain metastases.
1. Magnetic resonance angiography (MRA) is a non-invasive imaging technique that uses magnetic resonance imaging to visualize blood vessels and evaluate vascular anatomy and blood flow without using ionizing radiation or iodinated contrast material.
2. There are different MRA techniques including time-of-flight MRA, phase contrast MRA, and contrast-enhanced MRA. Time-of-flight MRA relies on differences in flowing and stationary blood signal while phase contrast MRA assesses velocity and direction of flow. Contrast-enhanced MRA uses gadolinium contrast to improve vessel depiction.
3. MRA has various clinical applications for evaluating carotid and intracranial arterial stenosis, aneurysms,
MR spectroscopy is a non-invasive technique that uses MRI to measure brain chemistry. It provides information about metabolites like NAA, creatine, and choline to help characterize lesions and diseases. Single-voxel MRS is less advanced but faster, while multi-voxel MRS examines more areas but takes longer. MRS is an additive test that is interpreted along with conventional MRI images to aid diagnosis.
BASICS OF NEUROANATOMY & BRAIN TUMOR RADIOLOGYKanhu Charan
The document discusses the basics of neuroanatomy and common brain tumors. It provides information on various sulci and gyri in the brain and their importance. The key sulci and gyri discussed include the central sulcus, which separates the frontal and parietal lobes; the intraparietal sulcus, which separates the superior and inferior parietal lobules; and the calcarine sulcus, which separates the cuneus and lingual gyrus. Understanding the location and relationships of sulci and gyri is important for interpreting neuroimaging of the brain.
Superficial brain structures are drained by cortical veins and the superior sagittal sinus. Central brain structures drain into the deep venous system including the internal cerebral veins, vein of Galen, and straight sinus. The veins of Labbé and transverse sinuses drain the posterior temporal and inferior parietal lobes. MR venography and CT venography can assess the cerebral venous system, with each technique having advantages and disadvantages.
imaging in neurology - demyelinating diseasesNeurologyKota
This document discusses various demyelinating diseases that can be imaged in neurology. It provides images and descriptions of findings for multiple sclerosis, ADEM, NMO spectrum disorder, Susac syndrome, CLIPPERS, acute disseminated encephalomyelitis, acute hemorrhagic leukoencephalitis, acute necrotizing encephalopathy, and osmotic demyelination syndrome. It compares imaging features of MS and NMOSD that can help differentiate the two conditions. The document also discusses variants of MS like Marburg disease, Schilder disease, and Balo concentric sclerosis.
MRI is the gold standard for diagnosing multiple sclerosis (MS). It can detect focal demyelinating lesions appearing as hyperintense areas on T2-weighted MRI. Different MRI sequences like T1, T2, FLAIR, and gadolinium contrast help identify lesions at various stages. MS lesions typically occur in periventricular white matter, corpus callosum, brainstem, and spinal cord. Advanced MRI techniques like MTR, DTI, and MRS provide additional insights into MS pathology by detecting subtle tissue damage. MRI plays a key role in the diagnostic criteria for MS by demonstrating dissemination of lesions in space and time. It is also used as an outcome measure in clinical trials to monitor
Presentation1.pptx sellar and para sellar massesAbdellah Nazeer
The document provides information on imaging techniques and differential diagnosis for sellar and parasellar masses. CT and MRI techniques are described for imaging the sella turcica region with details on slice thickness, field of view, and contrast usage. An anatomic approach is outlined to analyze sellar masses which involves identifying the pituitary gland, lesion location and characteristics, and establishing a differential diagnosis. Common pathologies that can occur in the sella and surrounding structures are then described individually, including the pituitary gland, stalk, optic chiasm, hypothalamus, carotid artery, cavernous sinus, and meninges. Imaging examples of lesions such as pituitary adenomas, craniopharyngiomas, and meningi
1. Adrenal imaging uses modalities like ultrasound, CT, MRI, and nuclear medicine to evaluate the adrenal glands and detect abnormalities.
2. CT is often the first choice to evaluate adrenal diseases and can characterize adrenal masses using attenuation values, enhancement patterns, and lipid content analysis.
3. Benign adrenal lesions include adenomas, myelolipomas, cysts, infections, and hemorrhages. Adenomas are the most common and often appear well-defined and homogeneous with characteristic lipid content and enhancement patterns on CT and MRI.
This document summarizes how functional magnetic resonance imaging (fMRI) can be used to see what areas of the brain are active while thinking. It explains that fMRI detects changes in blood oxygenation levels to map neural activity in the brain. The document outlines how fMRI works, describing that oxygen-rich and oxygen-poor blood have different magnetic properties and fMRI can pinpoint greater brain activity by tracking increased blood flow. Potential uses of fMRI discussed include brain mapping, understanding emotions, marketing research, and using fMRI to potentially detect lies.
Meningiomas are the most common non-glial tumors of the central nervous system. They are typically benign, slow-growing tumors that appear as well-circumscribed masses attached to the dura on imaging. CT often shows hyperattenuation and enhancement, while MRI demonstrates isointensity to gray matter and enhancement. Typical features include calcification, hyperostosis, and dural tail sign. Atypical features like cysts, hemorrhage or edema are less common. Advanced MRI techniques may help differentiate aggressive from non-aggressive meningiomas. Differential diagnosis includes other dural-based lesions.
Meningiomas account for 15% of all intracranial tumors and originate from the dura or arachnoid membranes. They are most common in middle-aged adults and affect women twice as often as men. Meningiomas are typically benign, slow-growing tumors that indent the brain as they enlarge. On CT imaging, meningiomas appear well-circumscribed, homogeneous, and hyperdense, and may induce hyperostosis of adjacent bone. MRI often reveals a characteristic "dural tail" sign of enhancement. Other histologic variants include hemangiopericytomas, which have a narrow dural attachment and lobulated shape.
This document summarizes various pathologies that can present as pineal region masses. It describes signs and symptoms such as Parinaud syndrome, hydrocephalus, precocious puberty, and pineal apoplexy. It then discusses tumors of pineal parenchymal origin including pineocytoma, pineal parenchymal tumor of intermediate differentiation, and pineoblastoma. It also covers germ cell tumors, pineal cysts, astrocytoma, and meningioma that can occur in the pineal region. Imaging findings for each condition are provided with examples.
fMRI technology uses the nuclear magnetic resonance (NMR) phenomenon to form images of neural activity in the brain. It relies on the different magnetic properties of oxygenated and deoxygenated hemoglobin. When neurons are active in a region of the brain, blood flow to that region increases, altering the ratio of oxygenated to deoxygenated hemoglobin and causing a change in the MRI signal. Spatial encoding techniques allow fMRI to locate these signal changes within the brain and form a 3D image showing patterns of neural activity.
Presentation1.pptx. radiological imaging of epilepsy.Abdellah Nazeer
1) Hippocampal sclerosis, characterized by hippocampal atrophy and increased signal intensity on MRI, is the most common epileptogenic abnormality found after epilepsy surgery.
2) Malformations of cortical development, including focal cortical dysplasias and heterotopias, are also common epileptogenic lesions found in surgical series, especially in patients with childhood-onset seizures.
3) In addition to structural abnormalities, low-grade gliomas and hamartomas located near the cerebral cortex are also important causes of drug-resistant epilepsy that may require surgery.
Magnetic resonance spectroscopy (MRS) is a noninvasive imaging technique that measures metabolite levels in tissues. It works by detecting signals from atomic nuclei such as hydrogen placed in a strong magnetic field. MRS is useful for evaluating brain tumors, infections, demyelinating diseases, and neurodegenerative conditions. It provides diagnostic information by analyzing peak levels of metabolites including NAA, creatine, choline, and lactate. MRS can help distinguish tumors from other lesions, detect radiation necrosis, and monitor treatment response. It is also used to diagnose inborn errors of metabolism and mitochondrial disorders.
This document summarizes evidence from 27 trials involving over 10,000 participants on the safety and efficacy of clot-dissolving drugs (thrombolytics) such as alteplase for treating acute ischemic stroke. The trials compared thrombolytics administered intravenously or intra-arterially within 4.5 hours of stroke onset to placebo or no treatment. Thrombolytics were found to improve outcomes after stroke but also increase the risk of serious bleeding in the brain. While thrombolytics can restore blood flow and reduce brain damage if given promptly, the risks and benefits were shown to depend on the time since stroke onset.
These are slides for an introductory lecture on fMRI/MRI and analysis of fMRI data. The corresponding tutorial is available on my website kathiseidlrathkopf.com
This document provides an overview of fetal MRI as a diagnostic imaging technique. It includes:
- An introduction and foreword discussing the technical advances and clinical applications of fetal MRI.
- A table of contents outlining the various topics to be covered across 29 chapters, including normal and pathological anatomy and development of various fetal organs as assessed by MRI.
- Information about the editors and editorial board who are international experts in fetal MRI and medical imaging.
- A preface by the editor, Dr. Daniela Prayer, introducing the aims and scope of the book.
Functional magnetic resonance imaging (fMRI) indirectly measures brain activity by detecting changes in blood flow and oxygenation. It uses the difference in magnetic properties between oxygenated and deoxygenated hemoglobin, known as the blood oxygen level dependent (BOLD) signal. The BOLD signal is slow and noisy, peaks around 6 seconds after stimulation, and involves subtracting conditions to identify statistically significant activity changes. fMRI data is overlaid on high-resolution structural scans and analyzed using specialized maps of visual and other functional areas.
NNI offers functional MRI analysis services to assess cognitive functions using 6 brief protocols covering areas like picture naming, verbal fluency, face memory, and trail making. They provide detailed statistical reports showing brain activation maps. Case studies demonstrate different activation patterns in patients with issues like traumatic brain injury or matrix reasoning deficits. The services aim to enhance patient assessment, clarify diagnoses, and monitor treatment outcomes in a cost-effective manner compatible with standard MRI scanners.
A simple introduction to fMRI study design for social science and other researchers outside the field who might want to design a study using fMRI brain scanning technology
MRI provides detailed images of the brain without exposing patients to radiation. It is useful for evaluating conditions like tumors, strokes, and multiple sclerosis. The document describes the MRI procedure for brain imaging including patient preparation, head coils, sequences, and protocols. Key sequences discussed are T1-weighted, T2-weighted, FLAIR, diffusion weighted, MR angiography, and MR venography.
Vickie Voxel explains fMRI, the hemodynamic response function (HRF), and the blood oxygen level dependent (BOLD) signal in 3 sentences: The HRF models how a voxel's color changes over 20 seconds as blood oxygen levels rise and fall in response to neuronal firing, appearing brighter on fMRI images where there is more oxygen; this hemodynamic response is measured as the BOLD signal, which shows brain activity through shades of light and dark on fMRI images. Vickie describes how the fMRI machine detects differences in blood oxygen levels through variations in magnetism to visualize the HRF and map brain activity.
O documento discute tensores de difusão e trato grafia, descrevendo como a difusão anisotrópica nos tecidos biológicos pode ser quantificada através de tensores. Ele também resume as principais fibras de associação e projeção no cérebro, incluindo o cíngulo, fascículos occipitofrontal superior e inferior, fascículo uncinado, fascículo longitudinal superior e inferior, e trato geniculo-calcarino.
This study used diffusion tensor imaging to analyze water diffusion along the corpus callosum in individuals with and without multiple sclerosis. They found that diffusion properties, particularly fractional anisotropy values, differed between segments of the corpus callosum and could predict whether someone had MS. A logistic regression model splitting the corpus callosum into three equal segments had the best prediction accuracy of 76%. Future work should account for additional factors like age and location along the corpus callosum to improve diagnostic models of MS.
This document describes the design of an integrated EEG and tDCS device. It aims to provide simultaneous EEG recording and tDCS stimulation at a lower cost than existing research devices. The device uses an Arduino, EEG amplification circuit, and connects to a commercial tDCS device. Validation testing showed the EEG signals matched those from a commercial device. Future work includes addressing noise issues and further development by Dr. Amthor's lab. The goal is to enable lower-cost neuroscience research combining EEG and tDCS.
Cosmo-not: a brief look at methods of analysis in functional MRI and in diffu...CosmoAIMS Bassett
The document provides an overview of functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) analysis methods including Granger causality, principal component analysis (PCA), and independent component analysis (ICA). It describes how fMRI measures brain activity indirectly through the blood oxygenation level dependent (BOLD) signal and how this can be used to identify functional brain networks. It also briefly discusses DTI for analyzing structural brain connections and resting state fMRI for studying functional networks without an explicit task.
Diffusion tensor imaging (DTI) allows the measurement of water diffusion in tissues to probe microstructure beyond image resolution. DTI characterizes diffusion anisotropy, in which diffusion varies with direction. In white matter, diffusion is fastest along axonal fibers and slower perpendicular, revealing fiber orientation. DTI exploits this to map white matter tracks in the brain. The article reviews DTI concepts and applications like fiber tracking, which combined with functional MRI may provide insights into brain connectivity.
The document discusses the fundamentals and work mechanism of magnetic resonance imaging (MRI). It introduces MRI as a medical instrument used to scan and image the inside of the body. The author's PhD focus and the increased demand for MRI exams are cited as reasons for choosing this topic. The aim is to familiarize the reader with the MRI machine and what happens inside during an exam by explaining its main parts, work mechanism, image processing, advantages, disadvantages, and predictions for future development.
There are two main types of MRI sequences: spin echo (SE) and gradient echo (GE). SE produces better image quality but has longer scan times, while GE has shorter scan times. Key MRI parameters are repetition time (TR) and echo time (TE). Different MRI weightings (T1, T2, PD, FLAIR) provide contrast between tissues. Advanced MRI techniques like DWI, PWI, and MRS provide additional clinical information on diffusion, perfusion, and metabolism. Functional MRI (fMRI) uses the BOLD contrast to non-invasively map functional brain activity with good spatial and temporal resolution. MRI and its variants are useful clinical tools for diagnosis, treatment planning, and studying brain
Intro to Transcranial Direct Curent Stimulation (tDCS)Daniel Stevenson
This document summarizes Transcranial Direct Current Stimulation (tDCS). It discusses the history of tDCS, how it works, applications in therapeutic and enhancement contexts, physiological effects and basis, safety considerations, and the future of research. tDCS involves applying a weak electrical current to the brain via electrodes to modulate cortical excitability. It has therapeutic potential for conditions like depression, motor rehabilitation, and is being studied for cognitive enhancement. Research suggests its effects are mediated by changes in neuronal membrane potentials and synaptic plasticity.
The document provides an introduction to functional magnetic resonance imaging (fMRI). It discusses how fMRI works by detecting changes in blood oxygenation, which serves as an indirect measure of neural activity. The basics of MRI are also reviewed, including how MRI uses strong magnetic fields and radio waves to generate images based on magnetic properties of tissue. Example fMRI studies measuring brain activity in response to visual stimuli are presented.
FMRI is a functional neuroimaging technique that uses MRI technology to measure brain activity through changes in blood flow and oxygen use. When an area of the brain is in use, blood flow to that region increases. FMRI relies on this coupling of cerebral blood flow and neuronal activation, using the BOLD contrast method to observe different active areas of the brain. A neuron is an electrically excitable cell that processes and transmits information through electrochemical signals.
Magnetic resonance imaging (MRI) uses strong magnets and radio waves to produce detailed images of the inside of the body without using ionizing radiation. An MRI machine contains a powerful magnet to align hydrogen atoms in the body. Radio waves are then used to excite the atoms, which emit signals as they relax. These signals are detected by antennas and used by a computer to generate 2D or 3D images of tissues and organs. MRI provides excellent soft tissue contrast and is useful for imaging the brain, muscles, joints, and other internal organs. While it has advantages over CT in avoiding radiation, MRI scans can be costly and some patients may find the enclosed scanner space claustrophobic.
This document discusses epilepsy surgery evaluation and outcomes. It notes that about one-third of epilepsy patients have seizures that cannot be controlled with medication. For these patients, surgical therapy can be an important treatment option. The goals of presurgical evaluation are to localize the epileptogenic zone and assess risk to brain functions from surgery. Evaluations may include brain imaging, video-EEG monitoring, neuropsychological testing, and in some cases invasive monitoring. Common indications for surgery include mesial temporal lobe epilepsy and lesions. Seizure freedom rates after surgery range from 50-90% depending on the specific diagnosis and evaluation findings. Outcome measures also consider cognitive and quality of life impacts.
Direct electrical stimulation is considered the gold standard for brain mapping during tumor resection near eloquent brain regions. Preoperative techniques like fMRI, DTI, EEG, MEG, and TMS provide information on functional areas of the brain. Intraoperative methods include direct electrical stimulation, electrocorticography, intraoperative MRI, and real-time neuropsychological testing. Awake craniotomy allows for more accurate brain mapping compared to asleep craniotomy, though it requires a highly trained team and can cause patient discomfort. The goal of brain tumor surgery has shifted to more extensive or total resections while preserving quality of life using advanced brain mapping techniques.
This document is a final progress report for an fMRI study investigating individual differences in visual perception within low signal-to-noise environments. The study used a random dot motion task with varying coherence levels to evaluate brain activation patterns across 15 participants. Preliminary results found some variability between individuals in activated brain areas. Further analysis is needed to characterize differences between subjects and better understand individual abilities in visual signal detection.
Functional magnetic resonance imaging (fMRI) techniques like BOLD-fMRI can noninvasively image the brain with high spatial and temporal resolution. BOLD-fMRI measures oxygenated blood flow changes to map brain activity. It has several applications including studying language, vision, movement, and memory. Other fMRI methods include perfusion fMRI, diffusion-weighted fMRI, and MRI spectroscopy, which can provide additional functional or metabolic information about the brain. These techniques hold promise for advancing understanding of psychiatric and neurological disorders.
Positron-emission tomography studies of cross-modality inhibition in selectiv...Dr Brendan O'Sullivan
Published in 1994, this groundbreaking paper featured the research of Professor Per Roland, Professor Ryuta Kawashima (of “Brain Training” fame) and Professor Brendan O’ Sullivan.
This landmark research was the first to prove in human brain imaging studies that visual attention is impaired when we do other attention-competing tasks such as manual tasks such as using mobile phones while driving.
Kohut Literature Review fMRI correctionsJulie Kohut
Functional magnetic resonance imaging (fMRI) is a noninvasive brain mapping technique that measures blood flow and oxygen levels to detect brain activity. fMRI is used clinically to study brain recovery after stroke, pre-surgical planning by locating functional areas near tumors, and identifying seizure onset zones. It has advantages over other imaging methods as it provides detailed brain images without radiation exposure. While offering insights, fMRI also has limitations such as sensitivity to patient movement and drugs affecting blood flow measurements. Continued research aims to improve fMRI for applications in neurology, psychology, marketing and developing lie detection techniques.
This document discusses various gadgets used in neurosurgery including neuronavigation systems. Neuronavigation uses preoperative images like CT and MRI to provide navigation during surgery. It helps localize lesions, perform biopsies and resections, and avoid damaging eloquent areas. Accuracy is typically around 2mm. While helpful, it can be time-consuming and restrict head movement. Future developments may involve microsurgical robots to compensate for brain shift. Fluorescence imaging using agents like 5-ALA and sodium fluorescein can also help identify tumor margins during surgery but have limitations. Overall, neuronavigation and fluorescence are useful adjuncts but experience and anatomy knowledge remain important.
The document discusses using machine learning techniques to classify brain images as normal or abnormal. Over 700 unlabeled patient brain images would be labeled and preprocessed, then classified as "brain" or "not brain" using a neural network. Brain images would then be classified as normal or abnormal based on a convolutional neural network trained on labeled data. Related work applied similar techniques using autoencoders and GANs to detect abnormalities like tumors and lesions in MRI images, achieving classification accuracy from 68-62% compared to simpler thresholding methods. The unsupervised models generally outperformed supervised models at identifying anomalies.
The study investigates the heritability of the anxious temperament (AT) phenotype in adolescent rhesus monkeys and its relationship to brain circuitry. Researchers found that the right dorsal amygdala, left hippocampus, and amygdalostriatal transition zone showed the highest predictability of AT from brain imaging data. Pedigree and phenotype analysis determined that the AT phenotype was heritable and metabolic activity in specific brain regions like the hippocampus was more heritable than in other regions like the amygdala.
This document discusses proton magnetic resonance spectroscopy (1H MRS) of the central nervous system. 1H MRS is a noninvasive technique that provides information about brain biochemistry and metabolism. It works by detecting different resonant frequencies of hydrogen nuclei in molecules, which are influenced by chemical bonds. The document outlines the basic principles and techniques of 1H MRS, including single voxel spectroscopy and magnetic resonance spectroscopic imaging. It discusses the clinical applications of 1H MRS for characterizing different brain pathologies such as tumors, infections, and treatment monitoring. Specific metabolic patterns are described for analyzing different brain tumors, meningiomas, and primary CNS lymphoma.
Structural neuroimaging plays an important role in the assessment and diagnosis of different types of dementia. For Alzheimer's disease, MRI typically shows atrophy of the medial temporal lobes including the hippocampus. Vascular dementia is characterized by multiple brain infarcts visible on CT or MRI. Frontotemporal dementia demonstrates frontal and temporal lobe atrophy that can be asymmetric. Dementia with Lewy bodies may show mild generalized atrophy on MRI with occipital hypometabolism on PET. Scales like the MTA scale are used to quantify hippocampal atrophy, while MRS can detect metabolic changes in dementia. Neuroimaging thus aids in distinguishing dementia subtypes and excluding other pathological conditions.
Magnetoencephalography an emerging biological marker for neurodegenerative an...Adonis Sfera, MD
Magnetoencephalography (MEG) is a technique that measures magnetic fields produced by electrical currents in the brain to map functional areas with great temporal resolution. MEG detects alterations in brain structure correlated with changes in function as seen with MRI. A new combined MEG-MRI device can simultaneously record ultra-low-field MRI and MEG to unprecedentedly locate brain activity. MEG has accurately diagnosed PTSD at 90% by identifying patterns unique to sufferers, and combining with diffusion tensor imaging may further improve diagnostic accuracy.
This document discusses quantitative tests used to evaluate facial nerve function, including physical examination, topognostic tests like lacrimal function and taste tests, and imaging. It describes the House-Brackmann grading system for facial paralysis and limitations in evaluating acute paralysis. Sunderland's classification of peripheral nerve injuries is explained, categorizing injuries from neurapraxia to neurotmesis. Pathophysiology of various types of facial nerve lesions is discussed.
Emerging MRI and metabolic neuroimaging techniques in mild traumatic brain in...IntesarAldweri
Traumatic brain injury (TBI) is one of the leading causes of death worldwide, and mild traumatic brain injury (mTBI) is the most common traumatic injury.
This document discusses quantitative analysis of radiologic images using techniques like image segmentation, registration, and statistical atlases. It notes that computers can help address human limitations in measurement, detection of subtle abnormalities, and evaluation of complex patterns. Key techniques include using statistical atlases to capture normal anatomical variation, registering images to integrate data from multiple individuals, and performing pattern classification using machine learning to aid diagnosis. The goal is for computers to complement humans by providing increased reproducibility, quantification, and analysis of non-focal or complex spatio-temporal changes.
This document describes a study that used FreeSurfer software to obtain volumetric measurements of subcortical structures and cortical thickness measurements from MRI scans of patients with Alzheimer's disease, mild cognitive impairment, or frontotemporal dementia, as well as healthy control subjects. The study aimed to identify diagnostic markers for these neurodegenerative diseases but was unable to determine correlations between brain structures and specific diseases due to confidentiality constraints on disease diagnoses. Common errors during FreeSurfer processing were corrected before analysis of subcortical and cortical thickness results.
Amyotrophic Lateral Sclerosis (ALS) is the most common progressive neurodegenerative disorder reflecting
the degeneration of upper and lower motor neurons. Motor neurons controls the communication between nervous
system and muscles of the body. ALS results in the loss of voluntary control over muscular activities along with the
inability to breathe and the maximum life expectancy of affected individual will be 3-5 years from the onset of
symptoms. But the lifetime of affected people can be extended by early detection of disease. The usual methods for
diagnosis are Electromyography (EMG), Nerve Conduction Study (NCS), Magnetic Resonance Imaging (MRI) and
Magneto-encephalography (MEG). But some of these methods may erroneously result in neuropathy or myopathy
instead of ALS and some do not provide any biomarker. EEG is comparatively least expensive method and it
provides biomarker for ALS detection. ALS is always associated with fronto-temporal dementia (FTD). The spectral
analysis of EEG will reveal the structural and functional connectivity alterations of the underlying neural network
that occurs due to FTD and it can generate potential biomarkers for the early detection of ALS. A novel algorithm
has been developed by exploiting the Dual Tree Complex Wavelet Transform (DTCWT) technique and it can
overcome the short comes of existing methods for the analysis and feature extraction of EEG. Deterministic
biomarkers were obtained from spectral analysis of EEG and the proposed algorithm provided 100% accuracy for all
the test datasets.
Tumor Detection Based On Symmetry InformationIJERA Editor
Various subjects that are paired usually are not identically the same, asymmetry is perfectly normal but sometimes asymmetry can benoticeable too much. Structural and functional asymmetry in the human brain and nervous system is reviewed in a historical perspective. Brainasymmetry is one of such examples, which is a difference in size or shape, or both. Asymmetry analysis of brain has great importance because itis not only indicator for brain cancer but also predict future potential risk for the same. In our work, we have concentrated to segment theanatomical regions of brain, isolate the two halves of brain and to investigate each half for the presence of asymmetry of anatomical regions inMRI.
Evaluation of visual function with opaque media Kunal Shinde
This document discusses methods for evaluating visual function when the ocular media is opaque, preventing direct visualization of the fundus. Both subjective and objective tests are described. Subjective tests include visual acuity, perception of light, entoptic phenomena using the Maddox rod or retinal blood vessels, and potential acuity meter. Objective tests include examination of the pupil, ultrasonography, electroretinography, electrooculography, and visual evoked potentials to assess retinal and macular integrity when the media is opaque. The results of these tests can help determine visual potential and guide surgical management.
This document discusses various pediatric musculoskeletal disorders and conditions that can affect the knee joint, as seen on imaging such as MRI and radiography. It covers developmental disorders like congenital absence of cruciate ligaments and discoid meniscus. It also discusses infectious diseases like osteomyelitis, inflammatory diseases such as pigmented villonodular synovitis, neoplastic conditions including benign tumors like osteochondroma and malignant tumors like osteosarcoma. A variety of imaging findings are presented for each condition.
Presentation1, Ultrasound of the bowel loops and the lymph nodes..pptxAbdellah Nazeer
Ultrasonography is used to examine the bowel loops and abdominal lymph nodes. It can detect various pathologies of the bowel including hypertrophic pyloric stenosis, duodenal hematoma, midgut volvulus, incarcerated inguinal hernia, Henoch Schönlein purpura, Crohn's disease, intussusception, and acute appendicitis. The ultrasound technique and appearance of these conditions are described along with images showing normal bowel anatomy for comparison. Specific features that help differentiate these pathologies are discussed.
This document contains 34 radiology case summaries. Case 1 describes a Salter-Harris type I ankle fracture with avulsion injury seen on X-ray. Case 2 describes bilateral triangle bone sclerosis of the iliac bones seen on pelvis X-ray and MRI in a patient with osteitis condensans ilii. Case 3 describes a Lisfranc fracture dislocation seen on foot X-ray.
This document contains multiple case studies and images related to soft tissue hemangiomas and neurofibromatosis. The cases demonstrate various imaging findings including: heterogeneous masses containing phleboliths characteristic of hemangiomas in muscle and soft tissue seen on X-ray and MRI; intramuscular hemangiomas appearing as well-circumscribed and hyperintense lesions on MRI; and neurofibromas appearing as plexiform masses showing atypical enhancement and causing skeletal abnormalities in neurofibromatosis type 1 and 2.
This document contains a list of over 80 medical conditions and diseases. It includes rare conditions like chondrodysplasia punctata, ranula, and lissencephaly as well as more common conditions like lipoma, adenomyosis, and osteosarcoma. The wide variety of medical topics covered suggests this list was intended as a study guide or reference for medical students or residents to test their knowledge of different pathologies.
Presentation1, radiological imaging of lateral hindfoot impingement.Abdellah Nazeer
This document discusses radiological imaging of lateral hindfoot impingement. It provides illustrations and images showing normal hindfoot anatomy as well as examples of talocalcaneal impingement, subfibular impingement, and combined impingement. MRI and CT images demonstrate bone marrow edema, cystic changes, sclerosis, and soft tissue swelling associated with impingement between the talus, calcaneus, and fibula. Measurements of hindfoot valgus angle are also shown on imaging to evaluate impingement and alignment. Case studies with patients presenting lateral ankle pain further demonstrate imaging findings of extra-articular hindfoot impingement.
Presentation2, radiological anatomy of the liver and spleen.Abdellah Nazeer
This document discusses the normal anatomy of the liver and spleen as seen on radiological CT scans. It describes the classic portal vein anatomy where the main portal vein bifurcates into right and left branches. It also shows images of variations in the arterial supply to segment IV of the liver, which can arise from either the left or right hepatic artery. Finally, it mentions examining the anatomy of the spleen but does not provide any details.
Presentation1, artifacts and pitfalls of the wrist and elbow joints.Abdellah Nazeer
1) The document discusses various normal anatomical structures and imaging artifacts that can be mistaken for abnormalities in MRI of the wrist and elbow joints.
2) Specific examples mentioned include "pseudoerosions" of wrist bones that are actually intraosseous blood vessels, as well as pseudodefects of the capitellum and trochlear bones of the elbow that appear as interruptions of the cortical bone.
3) The document emphasizes that these pseudodefects should not be confused with osteochondral lesions, as they do not exhibit marrow edema and occur in different locations. It provides images to illustrate examples of these normal variants.
Presentation1, artifact and pitfalls of the knee, hip and ankle joints.Abdellah Nazeer
The document summarizes common artifacts and pitfalls seen on MRI of the knee, hip, and ankle joints that can be mistaken for pathology but are actually normal anatomical variants or imaging findings. Some examples provided include meniscofemoral ligaments in the knee that can mimic meniscal tears, transverse ligaments that can appear to disrupt the meniscus, and popliteal tendon sheaths that can resemble lesions. For the hip, examples given are synovial pits, os acetabuli, the transverse acetabular ligament, perilabral recesses, and intraosseous contrast tracks in the acetabulum. Proper identification requires knowledge of anatomy and correlation across imaging planes.
Presentation1, radiological imaging of artifact and pitfalls in shoulder join...Abdellah Nazeer
This document discusses various normal anatomical variations and artifacts that can be mistaken for pathology on shoulder MRI images. It describes variations that can be seen in tendons like the biceps and rotator cuff, ligaments, labral structures, bone structures, and bone marrow. Specifically, it notes variations in tendon bifurcation and vascular structures, subtle differences between tendons in the rotator cuff, variants of ligaments and labral structures like the sublabral foramen, and normal anatomical grooves and depressions in bones that should not be confused with defects or lesions. Positioning artifacts are also discussed. The document aims to help radiologists avoid misdiagnosing these normal variants as pathological conditions.
Presentation1, radiological imaging of internal abdominal hernia.Abdellah Nazeer
This document summarizes different types of internal abdominal hernias as seen on radiological imaging. It describes the clinical presentation, anatomy, and characteristic radiographic features of various internal hernia types including paraduodenal, pericecal, transmesenteric, lesser sac, broad ligament, supravesical, and Petersen hernias. Key radiographic findings include clusters of small bowel loops in atypical locations and displacement or compression of surrounding organs. Vascular landmarks help identify the specific hernia type.
Presentation11, radiological imaging of ovarian torsion.Abdellah Nazeer
Ovarian torsion refers to the twisting of an ovary on its vascular pedicle, which can cut off its blood supply. It is a gynecological emergency that requires urgent surgery. Radiological imaging plays an important role in the diagnosis. Ultrasound is usually the initial imaging method, showing signs such as an enlarged ovary without blood flow. CT and MRI can further evaluate for complications like hemorrhage or infarction. Prompt diagnosis and treatment are needed to prevent ovarian necrosis from the loss of blood supply.
This document provides an overview of musculoskeletal MRI anatomy of the knee, ankle, hip, elbow and shoulder joints. It describes the imaging planes used to study each joint and surrounding structures like ligaments, tendons, muscles and neurovascular elements. Key anatomic landmarks of the joints are identified on MRI in different planes. Normal appearances of tissues like cartilage, bone and synovial fluid are also outlined.
Presentation1, new mri techniques in the diagnosis and monitoring of multiple...Abdellah Nazeer
This document discusses new MRI techniques for diagnosing and monitoring multiple sclerosis (MS). It recommends protocols for baseline and follow-up brain and spinal cord MRIs, including mandatory and optional sequences. Advanced techniques like double inversion recovery, diffusion tensor imaging, and MR spectroscopy are highlighted for improving detection of gray matter lesions and diffuse white matter damage compared to conventional MRI. The document concludes that while conventional MRI is important for MS, advanced techniques provide higher sensitivity and specificity for both lesions and normal-appearing brain tissue, furthering understanding of MS pathophysiology.
Presentation1, radiological application of diffusion weighted mri in neck mas...Abdellah Nazeer
This document summarizes the potential applications of diffusion-weighted MRI in evaluating neck masses. It discusses how DWI can help differentiate between benign and malignant neck masses based on apparent diffusion coefficient (ADC) values. DWI is also useful for predicting and monitoring treatment response in head and neck tumors by detecting changes in ADC values before changes in tumor size. DWI can help distinguish tumor recurrence from post-treatment changes based on qualitative and quantitative ADC assessments. The document concludes that DWI shows promise for applications in head and neck oncology but larger multicenter studies are still needed.
Presentation1, radiological application of diffusion weighted images in breas...Abdellah Nazeer
The document discusses the use of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values to characterize breast lesions. DWI was performed on 70 breast lesions which underwent biopsy. Malignant lesions showed lower ADC values than benign lesions. Using an ADC cutoff of 1.1×10^-3 mm2/s and normalized ADC ratio of 0.9 provided high sensitivity and specificity of 89.75% and 92.2% respectively in differentiating benign and malignant lesions. DWI is thus a potential adjunct to conventional breast MRI that can accurately characterize lesions.
Presentation1, radiological application of diffusion weighted images in abdom...Abdellah Nazeer
The document discusses the use of diffusion-weighted imaging (DWI) in abdominal and pelvic MRI. It finds that DWI improves lesion detection sensitivity, especially for metastases, and can help characterize lesions when gadolinium contrast is contraindicated. DWI provides quantitative tissue analysis without contrast and may help longitudinally assess tumor response to therapy. Given its merits and availability on most MRI systems, DWI should be considered a routine sequence in abdominal MRI protocols, particularly when contrast cannot be used.
Presentation1, radiological application of diffusion weighted imges in neuror...Abdellah Nazeer
1) The document discusses the use of diffusion-weighted MRI in detecting areas of restricted diffusion in various neurological conditions and diseases. It provides examples of several conditions that appear bright on DWI imaging such as acute ischemic stroke, traumatic brain injuries, encephalitis, spinal cord ischemia, and arterial dissections.
2) Restricted diffusion occurs when there is a reduction in the normal random movement of water molecules within tissues, appearing as hyperintense signals on DWI images. This can be caused by cellular swelling, reduced extracellular space, or fragmentation of cellular components.
3) The timing of imaging after an event such as stroke or trauma influences the appearance of lesions on DWI and ADC maps, with restricted diffusion detectable
Magnetic resonance imaging (MRI) was discovered in 1947 by two physicists and the first clinical images were obtained in 1977. MRI uses strong magnetic fields between 1-9 Tesla to align hydrogen atoms in the body and radio waves to elicit signals to form images. The document provides a brief history of MRI and discusses magnetic fields, relaxation processes, and pulse sequences used to generate MRI images.
2. Functional magnetic resonance imaging (fMRI) is increasingly
used in the work-up of patients at the preoperative stage to assess the
relationship between the functionally eloquent cortex and brain pathology. Inter-individual
normal variations of anatomy render such assessment unreliable based
on structural imaging alone despite the definition of clear anatomical landmarks.
This is even more of an issue when normal anatomy is obscured by a tumour mass
effect or when functional anatomy is altered due to cortical plasticity.
fMRI has seen a rapid evolution from its first human application in 1991 to an
essential tool in the exploration of human brain function, most prominently in the
scientific arena.
In 2007, new Current Procedure Terminology (CPT) codes were developed for fMRI
by the American Medical Association, signifying the transition of fMRI to a
valuable tool in a clinical setting.
Recent major advances in clinical fMRI make its acquisition, image processing, and
even integration of its findings for neuronavigational purposes relatively easy.
However, the technique is not without limitations and validation issues which are
easily forgotten when color activation maps become readily available at the single
click of a button. The theoretical background, the validity in brain tumour
patients, and several considerations of fMRI are addressed.
3. fMRI Background:
Blood Oxygenation Level-Dependent (BOLD) fMRI is the most commonly used
functional MR neuroimaging technique. BOLD fMRI takes advantage of the tight
link between local neuronal activity and blood flow, called neurovascular coupling
due to neurovascular coupling, blood flow and volume increase locally with an
increase of neuronal activity. This leads to an increase in oxygenated blood that is
disproportionate to the increased need of oxygen for neuronal activity. As a result,
there is a relative decrease of paramagnetic deoxygenated hemoglobin which in
turn leads to an increase of MR signal in those areas of the brain that are active.
Such signal changes are small and relative, which means that many
measurements need to be made, typically during an alternation of active and
baseline conditions in a task that aims to activate the functional brain region of
interest. Furthermore, the signal changes occur at a delay after and are more
prolonged than the neuronal activity, defined by the hemodynamic response
function. A statistical model is created to assess the correlation of the measured
signal changes with the task, taking the hemodynamic response function into
account. The resulting statistical map is threshold at a certain p or T value and
overlaid in color on a high-resolution anatomical image which is acquired
separately. This is the typical color “activation” map produced by an fMRI image
processing software, which is merely a combination of anatomical and statistical
information very indirectly representing neuronal activation.
4. Task-Based fMRI
For clinical application, almost exclusively task-based fMRI is used. During
the performance of a task by the subject in the scanner, rapid imaging of
the brain is performed. Typically, the entire brain is scanned at intervals of
3–5 s for a duration of about 5 min so that > 100 measurements are made
per task. The task consists of active and baseline conditions, which
commonly alternate in blocks of 20–40 s. Such so-called blocked
paradigms are statistically robust, since a lot of signal is acquired for each
condition, but they are restrained because they do not leave much room
for unexpected or short stimuli. In an event-related task design, individual
stimuli, each representing a specific condition, are presented in random
order and rapid succession. Such a task design offers the possibility to
present unexpected stimuli as well as many different condition. Rendering
it very flexible, but statistically less robust since the signal acquired per
condition is generally low. For clinical application, blocked designs are
generally well-suited and preferable.
5. Clinical Pre-Surgical fMRI Studies:
The aim of neurosurgery in brain tumour patients is maximum tumour resection, while
at the same time minimizing the risk of new functional deficits post-operatively. For
optimal results, the relationship between the tumour margins and eloquent brain
regions needs to be established as accurately as possible. The gold standard for such
assessment is intraoperative ECM, which has in fact been shown to significantly modify
long-term survival in low-grade glioma patients. However, intraoperative ECM is
invasive, requires experience and expertise of the neurosurgical team, increases
surgery duration, and requires awake and active participation, collaboration, and
motivation of the patient. Additionally, only a limited number of tasks can be tested.
Functional MRI may be used to make a risk assessment preoperatively, which is of
particular value in young low-grade glioma patients, to plan and guide the
neurosurgical approach, shorten surgery duration, and obtain prognostic information
prior to surgery. For fMRI to be used in such a setting, both high sensitivity and high
specificity are required. High sensitivity for eloquent brain regions is needed to reduce
the false negative rate so that no eloquent cortex is missed and no functional deficit is
induced by surgery. At high specificity the false positive rate is low, which means that
the visualized areas of activation relate to truly eloquent or critical brain regions. At
low specificity non-critical brain regions are also visualized, inducing the risk that such
areas are avoided at surgery and are subsequently exposed to a less extensive
resection than would have been possible.
6. Motor Function:
Motor cortex assessment has been validated in a multitude of studies
that generally report a good correlation between fMRI and
intraoperative ECM. Reported sensitivities for localization of the primary
motor cortex range from 88–100 % . Specificities are also high, ranging
from 87–100 % . Such high reliability may be contributed to by the robust
activation that is seen with simple motor tasks that can be easily
performed by the majority of patients. Also the functional anatomical
stability of the sensorimotor area, at both the macroscopic and
microscopic levels, probably contributes to the reliability of fMRI of
motor function . Spatial accuracy of fMRI motor cortex localization is
found to be within the range of 1–2 cm. Yetkin et al reported that all
intraoperative ECM and fMRI sites of activation were within 2 cm, while
87 % were within 1 cm. Importantly though, reliability seems to be
decreased with high tumour grades, as demonstrated by Bizzi et al. In
benign and malignant brain mass lesions in or near the primary motor
cortex, overall sensitivity was 88 %, but only 65 % in grade-IV gliomas.
7. Language Function:
In contrast to the high validity shown for fMRI of motor function, results
from language function validation studies are controversial, varying from
100 % sensitivity for fMRI to identify all critical language areas to as low
as 22 %. Reported specificity is even more variable, ranging from 0– 100 %.
Validation studies of fMRI of language function in brain tumour patients
are relatively scarce, are generally performed in small patient populations,
and suffer from differences in the validation methods used among the
studies, disparities of brain lesions, and the variety of the language tasks
performed preoperatively and during intraoperative ECM. The mapping of
language function is also more complex than that of the sensorimotor
cortex due to the lack of consistent surface landmarks and substantial
inter-individual variability. The language cortical network seems to consist
of critical regions, essential for language processing, and participating but
non-critical areas, which may be resected without inducing a permanent
language deficit. These areas cannot be reliably distinguished with fMRI,
resulting in low specificity of fMRI compared with intraoperative ECM.
8. Other Functions:
The visual cortex has been a frequent topic of study since the early days of
fMRI, due to its relatively strong BOLD response and easy implementation
of stimulus paradigms. Presurgical mapping of the primary visual cortex
has been described and may be indicated when the normal anatomy is
severely distorted by the tumour and/or when the brain structure of
interest is located deep inside the brain and cannot be assessed by ECM.
Commonly used stimulus paradigms are flashing lights presented with
light-proof goggles and reversing black-and-white checkerboards .
Another function that may be assessed with fMRI is visuospatial attention,
failure of which results in spatial neglect.
This condition arises with damage of the temporoparietal or frontal
cortex, the thalamus or the basal ganglia, generally of the right
hemisphere. It is an invalidating condition, in which patients behave as
if the left part of the world does not exist. Functional localization may be
assessed with fMRI using a line bisection task, in which patients are asked
to bisect 20-cm horizontal lines, which has been used successfully during
ECM.
9. Critical Issues:
There are several limitations of fMRI that need to be considered when using
the technique for pre-surgical assessment of brain tumour patients. These
include issues that are inherent to the technique, such as spatial and
geometric uncertainty, tumour effects on the BOLD signal, inter- and intra-individual
variability, lack of discrimination between essential and modulating
brain regions, and lack of information on the underlying white matter. The
imaging sequence used for BOLD fMRI is particularly sensitive to
postoperative effects, such as metallic implants and surgical staples, air
underneath the skull flap, and blood products, as well. This means that
additional care needs to be taken in patients who have had previous surgery,
biopsy, or hemorrhage. Small regions of hemosiderin deposition may not be
visible on conventional imaging, but will show large artifacts in the BOLD
fMRI data. Such artifacts are obscured on the fMRI activation color maps,
which would simply show decreased or no activation in the artefactual area.
It is therefore crucial that the raw data are scrutinized for such artifacts in
every patient. Other issues with pre-surgical fMRI, that may be resolved in
the future, are the lack of standardization of tasks and image processing
techniques.
10. Four resting state networks in a normal subject. Also shown are corresponding time courses of
the independent component coefficients.(Colors quantify the z-value of correlation of the time
series with the corresponding ICA coefficient. Either positive or negative z-values are shown.)
11. Activation patterns in response to visual stimuli. Note the lack of
activation in the central visual cortex when using projection screen.
12. Visual area locations. A, Parasagittal anatomical image from one subject
indicating the slice selection (perpendicular to the calcarine sulcus) for the
retinotopy measurements and the control conditions. B–D, Visual areas V1, V2,
V3, V3A, and V4v depicted on in-plane anatomies from a similar location (near the
middle of the 8 in-planes) in three control subjects. E–G, Visual areas depicted on
in-plane anatomies from a similar location in three dyslexic subjects.
13. Location of area MT1. A, Parasagittal anatomical image from one subject indicating the
slice selection (parallel to the calcarine sulcus) for the moving dots and the test conditions.
The blue lines were slices that contained the MT1 region of interest (ROI) in this subject. B–
D, Brain activity in one slice containing the MT1 ROI from three control subjects. Reddish
voxels show regions with greater response to moving versus stationary dot patterns.
Images were chosen to optimally show MT1 in the right hemisphere (arrows), although
activity from left hemisphere MT1 and V1 are also present in some cases. The image in B is
from the same brain as the sagittal image in A and corresponds to the most inferior of the
three blue slices. The MT1 ROI was defined by outlining (dotted line in B) the strongest
area of activity that was approximately lateral to the junction between the calcarine sulcus
and the parieto-occipital sulcus, and beyond the retinotopically organized visual areas.
E–G, Slices with MT1 ROIs in three dyslexic subjects.
14. This image is in
radiological format
and shows an
auditory language
map averaged over
40 subjects.
There is bilateral
primary auditory
cortex (yellow
arrows), left
Wernicke’s (green
arrows) and Broca’s
(red arrows), and
SMA (orange arrows).
In this auditory task,
the subject hears
phrases, such as “The
funny guys at the
circus” and thinks
in his/her mind of a
word that fits.
16. Figure 4. Functional reorganization of motor area was observed in the patients
with short term and long term spinal cord injury (sci).
Figure 4a. Control.
Figure 4b. Two years after sci.
Figure 4c. More than 10 years after sci.
17.
18.
19.
20. Localization of primary motor cortices in 28 years old patients with brain tumor:
Note that the posterior and medial displacement of motor cortices by the mass lesion
21. Localization of language cortices in 28 years old patients with brain tumor:
Note that the strong left lateralization of language activities.
25. fMRI in preoperative planning.
3a. Preoperative planning for brain biopsy in a patient with a lesion (arrow) in
the left frontal lobe (Broca’s area). Significant bilateral language activation
was observed in this patient.
3b. fMRI was used to determine the language area and its relation to the tumor
for a patient with glioblastoma (arrow).
26.
27.
28.
29.
30.
31.
32. Patient K, male, 37 years old, with glioblastoma in the left temporoparietal
area,activation from visual task, R - right hemisphere; L - left hemisphere.
33. Patient P, male, 28 years old, with glioblastoma in the left temporal lobe, activation
from visual and auditory tasks, R - right hemisphere; L - left hemisphere, WA –
activation in Wernicke's area. Red - activation elicited by visual task, blue - activation
elicited by auditory task, purple - activation that coincided in two tasks.
34. Patient KO, female, 53 years old, with glioblastoma in the left parietal area,
activation from visual task (red), R - right hemisphere; L - left hemisphere.
35. Preoperative (A) activity showing the focus
of activity in 4 patients obtained from the
comparison of the visuomotor conditional
blocks of trials with the motor control
blocks of trials and postoperative (B)
anatomical images. A: Functional MR
images show the focus of activity within
the rostral part of the premotor cortex in
the lateral view (in all patients) and in the
top view (in Case 2) of the cortical surface
rendering in standard stereotactic space of
the left hemisphere of each patient. The
gray shaded area of the cortical surface
shows the tumor location. Each blue cross
indicates the location of the preoperative
activity increase in the PMdr. The color
scale indicates the t value range. B:
Magnetic resonance images show the
cortical surfaces as renderings (in standard
stereotactic space) of the left hemisphere of
each patient based on the postoperative
MR image. The deformation of the cortical
surface shows the extent of the tumor
resection. The data demonstrate that, in
each patient, the region involved in the
visuomotor conditional function was not
removed during the tumor resection.
36. Images showing the
preoperative activity
obtained from the
comparison of the
motor control with the
visual control block of
trials. The cortical
surfaces are renderings
(in standard stereotactic
space) of the left
hemisphere of each
patient. The horizontal
yellow line indicates the
dorsoventral level of the
horizontal sections
illustrated in the images
on the right. The
increases in activity
correspond to the
location of the primary
hand motor region in
the precentral
knob of each patient,
37. Tumor heterogeneity Recognition Evaluation on the High Grade Glioma of
the BraTS dataset: Qualitative Example Case BRATS HG0001 a) Gadolinium T1 MRI
Original Image b) FLAIR MRI Original Image c) Overlap between Gadolinium T1 MRI
original image and the Ground Truth masks d) Overlap between Gadolinium T1 MRI
original image and the automatic recognized masks.(Red points are Edema and Cyan
point are the Active Tumor
38. Tumor heterogeneity Recognition Evaluation on the High Grade Glioma of
the BraTS dataset: Qualitative Example Case BRATS HG0001 a) Gadolinium T1 MRI
Original Image b) FLAIR MRI Original Image c) Overlap between Gadolinium T1 MRI
original image and the Ground Truth masks d) Overlap between Gadolinium T1 MRI
original image and the automatic recognized masks.(Red points are Edema and Cyan
point are the Active Tumor)
39.
40.
41. 18-year old boy with a glioma grade 3 (arrows) near the left rolandic area, demonstrating
the importance of fMRI in planning surgery and avoiding postoperative neurological
deficits. fMRI using a visuomotor paradigm showed functional activation less than 2 cm
posterior to the tumour and partial resection was proposed (A,B). Partial resection was
performed using intra-operative cortical stimulation, and followed by application of gene
therapy in the tumour remnant posteriorly. Postoperatively, no motor deficit was present.
42. 26-year old man with right frontal glioma demonstrating the role of fMRI in
deciding on operability. This man was left-handed which increased chances that
language areas are not confined solely to the left hemisphere. fMRI using a verb
generation paradigm showed that the language areas Broca (B) and Wernicke (W)
were strongly lateralized to the left hemisphere because no activation was seen in
the right hemisphere. Complete resection of the right frontal glioma (T) was
performed and the patient did not have any language deficit postoperatively.
43. 59-year old woman with arteriovenous malformation (AVM) in the right parieto-occipital
region, demonstrating risk for postoperative deficit because activation areas are less
than 2 cm of the lesion. fMRI using a visuomotor paradigm showed visual activation
areas (green) medially and caudally relative to the AVM (circle), at less than 1 cm
distance. After endovascular approach with partial embolisation, complete resection was
performed surgically. Postoperatively, a left lower quadrant anopsy was present.
44. (Top row) Acquired axial CT and anatomical MRI slices from the AVM patient.
(Bottom row left) fMRI activation map fused with the anatomical MRI data
showing the Broadmann-17 functional structure and (lower right) corresponding
color-coded (red = left-right; green= anterior-posterior; blue = superior-inferior).
The FA map was used for calculating the tractography data.
45. Recurrent left parietal lobe
anaplastic astrocytoma in 37-
year-old right-handed woman.
Surgery was not initially planned
because of presumed
involvement of receptive speech
area. Left inferior and middle
frontal gyral activation (yellow
arrows) is consistent with
dominant expressive speech area
and is located at anterior border
of more cephalad component of
lesion. Left superior and middle
temporal gyral activation (green
arrows) is consistent with
dominant receptive speech area
and abuts inferior border of
temporal component of lesion,
with superior temporal gyral
activation component lying
anteroinferior to lesion.
46. Preoperative fMRI in patients during contralesional movements. Preoperative anatomic and
functional MRI in Patients 1, 5, and 8 (left column) showed large tumoral infiltration of the
supplementary motor area (SMA) (asterisk), associated with under activity in the SMA in the
pathologic hemisphere, and over activity in the healthy SMA resulting in negative magnitude
laterality indices (LI) (0.40, 0.12, 0.06). Recovery began within the first 3 days and lasted
between 30 and 60 days. In Patients 6, 9, and 11 (right column), tumoral infiltration (asterisk)
was lower, and LI remained positive (0.08, 0.19, 0.12). Arrows indicate predominant SMA
activation. Recovery began after 7 to 21 days, and lasted between 90 and 120 days.
47. Postoperative fMRI. Anatomic and functional MRI in one representative control
and in Patients 4, 6, and 12 during ipsilesional (IL) and contralesional (CL)
movements after surgery. In controls and in patients during IL movements,
supplementary motor area (SMA) (arrow) and premotor cortex (PMC) (arrowhead)
activation predominated in the hemisphere contralateral to the moving hand. In
patients during CL movements, SMA activation was located in the healthy
hemisphere and PMC activation became more important in the ipsilateral healthy
hemisphere. The resection cavity is indicated by the asterisk on axial planes.
48. Axial TIWI in neurologic format show left megalencephaly with an enlarged dysmorphic
left cerebral hemisphere. There is poly microgyria as well as heterotopia. During this
auditory task, there was only activation in the right primary auditory cortex (yellow arrow)
rather the expected bilateral activation. (Color version of figure is available online.)
49. Conclusions.
Functional MRI is a valuable tool in the pre-surgical assessment of
brain tumour patients, but needs to be used with care.
Interpretation of the results requires a lot of experience and may be
difficult. Knowledge of functional brain anatomy is a first
requirement for risk evaluation and to determine which
fMRI tasks need to be performed. The shortcomings of fMRI in a
clinical setting as described above need to explicitly be taken into
account in every patient. In our institution, fMRI, combined with DTI
tractography, is used to aid neurosurgical planning but
intraoperative ECM is always used for confirmation when activation
is shown in the proximity of the brain tumour or if activation is
atypical. Most importantly, the absence of fMRI activation does not
exclude the presence of functional neuronal tissue, not even within
infiltrative tumours.