Anatomy of Brain by MRI
In this presentation we will discuss the cross sectional anatomy of brain. Then we will discuss the Most common diseases to be evaluated by brain imaging.
In my opinion this presentation is a road map for beginars.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Anatomy of Brain by MRI
In this presentation we will discuss the cross sectional anatomy of brain. Then we will discuss the Most common diseases to be evaluated by brain imaging.
In my opinion this presentation is a road map for beginars.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
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Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
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1. PRINCIPLES OF MRI BRAIN
BY : DR. MANOJ SEERVI & DR. SURESH CHOUDHARY
INCHARGE: DR. ACHAL SHARMA
FACUILTY: DR. J S SHEKHAWAT
DR. GAURAV JAIN
DR. NAVNEET AGARWAL
2. HISTORICAL ASPECT
• 1940s –Felix Bloch &E. Purcell: discovered just after world
war II & named Nuclear Magnetic Resonance (noble prize
1952)
• 1973: Paul Lauterbur published the first nuclear magnetic
resonance image and the first cross-sectional image of a living
mouse in January 1974
• 1977 – Mansfield: first image of human anatomy, first echo
planar image
• 1990s - Discovery that MRI can be used to distinguish
oxygenated blood from deoxygenated blood ,it leads to
Functional Magnetic Resonance imaging (fMRI)
• Paul Lauterbur and Peter Mansfield won the Nobel Prize in
Physiology/Medicine (2003) for their pioneering work in
MRI
3. The first Human MRI scan was performed on 3rd july 1977 by Raymond
Damadian, Minkoff and Goldsmith.
5. MRI is based on the principle of nuclear magnetic resonance
(NMR)
• Two basic principles of NMR
1. Atoms with an odd number of protons have spin
2. A moving electric charge, be it positive or negative,
produces a magnetic field
• Body has many such atoms that can act as good MR nuclei (1H,
13C, 19F, 23Na)
• MRI utilizes this magnetic spin property of protons of
hydrogen to produce images.
• In our natural state Hydrogen ions in body are spinning in a
haphazard fashion, and cancel all the magnetism. When an
external magnetic field is applied protons in the body align in
one direction.
BASIC PRINCIPLES OF MRI
6. Why Hydrogen ions are used in MRI?
1. Hydrogen nucleus has an unpaired proton which
is positively charged
2. Every hydrogen nucleus is a tiny magnet which
produces small but noticeable magnetic field
3. Hydrogen is abundant in the body in the form
of water and fat
4. Essentially all MRI is hydrogen (proton) imaging
7. • TE (Echo Time) : the time between the delivery of the RF
pulse and the receipt of the echo signal
• TR (Repetition Time) : The time between two excitations
is called repetition time.
TR & TE
8. • By varying the TR and TE one can obtain T1WI and T2WI.
• In general a short TR (<1000ms) and short TE (<45 ms) scan
is T1WI.
• Long TR (>2000ms) and long TE (>45ms) scan is T2WI.
9. BASIC MR BRAIN SEQUENCES
• ROUTINE SEQUENCES
– T1 – for anatomy
– T2- for pathological details
– FLAIR – suppress fluid
• SPECIAL SEQUENCES
– DWI – for infarcts, abscess , tumour detection
– ADC – for differentiation of different age of infarcts
– MRA – for arterial details
– MRV – for venous details
– MRS – spectroscopy for chemical compositions of the lesion
– GRE
– FIESTA(FAST IMAGING EMPLOYING STEADY STATE ACQUISITION)
/CISS(CONSTRUCTIVE INTERFERENCE STEADY STATE),
– STIR
– SWI
10. • SHORT TE
• SHORT TR
• BETTER ANATOMICAL DETAILS
• FLUID : DARK/CSF BLACK
• GRAY MATTER : GRAY
• WHITE MATTER: WHITE
T1 W IMAGES
11. • Most of pathologies are DARK/ HYPOINTENSE
on T1
• BRIGHT ON T1
– Fat
– Sub acute H’age (Methaemoglobin)
– Melanin
– High Protein Contents
– Posterior Pituitary appears bright on T1
(Neurosecretory granules)
– Gadolinium contrast
– Cholesterol
12. • LONGTE
• LONG TR
• BETTER PATHOLOGICAL DETAILS
• FLUID: BRIGHT/Hyperintense
• GRAY MATTER : RELATIVELY BRIGHT
• WHITE MATTER: DARK
T2 W IMAGES
15. • LONG TE
• LONG TR
• SIMILAR TO T2 EXCEPT FREE WATER SUPRESSION
(INVERSION RECOVERY)
• CSF : DARK
• GRAY MATTER : RELATIVELY BRIGHT
• WHITE MATTER: DARK
• Most pathology is BRIGHT
• Hydrocephalous: Periventricular hyperintensity(CSF
ooze)
• Especially good for lesions near ventricles or sulci or
CSF containing spaces (eg Multilpe Sclerosis)
FLAIR (Fluid Attenuated Inversion Recovery Sequences)
Same as T2
with CSF
suppression
19. Clinical Applications of FLAIR sequences:
• Used to evaluate diseases affecting the brain parenchyma neighboring
the CSF-containing spaces for
eg: MS & other demyelinating disorders.
• Unfortunately, less sensitive for lesions involving the brainstem &
cerebellum, owing to CSF pulsation artifacts
• Mesial temporal sclerosis (MTS) (thin section coronal FLAIR)
• Tuberous Sclerosis – for detection of Hamartomatous lesions.
• Helpful in evaluation of neonates with perinatal HIE.
20. T1W T2W FLAIR(T2)
TR SHORT LONG LONG
TE SHORT LONG LONG
CSF LOW HIGH LOW
FAT HIGH HIGH MEDIUM
GREY MATTER LOW HIGH HIGH
WHITE MATTER HIGH LOW LOW
EDEMA LOW HIGH HIGH
21. GRADATION OF INTENSITY
IMAGING
CT SCAN CSF Edema White
Matter
Gray
Matter
Blood Bone
MRI T1 CSF Edema Gray
Matter
White
Matter
Cartilage Fat
MRI T2 Cartilage Fat White
Matter
Gray
Matter
Edema CSF
MRI T2 Flair CSF Cartilage Fat White
Matter
Gray
Matter
Edema
55. Splenium of
Corpus
callosum
Genu of corpus
callosum
Pons
Superior
Colliculus
Inferior
Colliculus
Nasal Septuml
Medulla
Body of corpus
callosum
Thalamus
56. Cingulate Gyrus
Genu of corpus
callosum
Ethmoid
air cells
Oral cavity
Splenium of
Corpus
callosum
Fourth Ventricle
75. Coronal Section of the Brain at the level of Pituitary gland
Post Contrast Coronal T1 Weighted MRI
sp
np
Frontal lobe
Corpus callosum
Frontal horn
III
Pituitary stalk
Pituitary gland Caudate nucleus
Optic nerve
Internal carotid artery
Cavernous sinus
76. CENTRAL SULCUS
•Upper T sign : the superior frontal sulcus intersects the precentral sulcus in a
"T" junction. The central sulcus is the next posterior sulcus.
•L sign: the superior frontal gyrus intersects precentral gyrus in an "L"
junction. The central sulcus is immediately posterior.
•Lower T sign: the inferior frontal sulcus terminates posteriorly in the
precentral sulcus in a "T" junction. The central sulcus is the next posterior
sulcus.
•M sign: the inferior frontal gyrus has a characteristic "M" configuration and
terminates posteriorly in the precentral gyrus. The central sulcus is
immediately posterior.
77.
78.
79.
80.
81.
82. Bracket sign: the marginal sulcus is visible immediately posterior to the
central sulcus, and is easily identifiable of sagittal paramedian images as the
continuation of the cingulate sulcus
sigmoidal hook (handknob, omega) sign: the precentral gyrus bulges
posteriorly at the hand motor area
bifid postcentral gyrus sign: the postcentral gyrus is split medially by the pars
marginalis of the cingulate sulcus
U sign: the most inferolateral extent of the central sulcus is capped by a U-
shaped gyrus – the subcentral gyrus – which abuts the lateral fissure
83. • Free water diffusion in the images is Dark (Normal)
• Acute stroke, cytotoxic edema causes decreased rate of water
diffusion within the tissue i.e. Restricted Diffusion (due to
inactivation of Na K Pump )
• Increased intracellular water causes cell swelling
• Areas of restricted diffusion are BRIGHT.
• Restricted diffusion occurs in
– Cytotoxic edema
– Ischemia (within minutes)
– Abscess
DIFFUSION WEIGHTED IMAGES (DWI)
84. Other Causes of Positive DWI
• Bacterial abscess, Epidermoid ,Acute demyelination,
Acute Encephalitis, CJD(Creutzfeldt-Jakob disease)
• T2 shine through ( High ADC)
• To confirm true restricted diffusion - compare the DWI image
to the ADC.
• In cases of true restricted diffusion, the region of
increased DWI signal will demonstrate low signal on
ADC.
• In contrast, in cases of T2 shine-through, the ADC will be
normal or high signal.
85. • Calculated by the software.
• Areas of restricted diffusion are dark
• Negative of DWI
– i.e. Restricted diffusion is bright on DWI,
dark on ADC
NON-ISCHEMIC CAUSES of low ADC :
• Abscess
• Lymphoma and other tumors
• Multiple sclerosis
• Seizures
• Metabolic (Canavans Disease)
APPARENT DIFFUSION COEFFICIENT Sequences
(ADC MAP)
86.
87. • TheADC may be useful for estimating the lesion age and
distinguishing acute from subacute DWI lesions.
• Acute ischemic lesions can be divided into Hyperacute
lesions (lowADC and DWI-positive) and Subacute
lesions (normalizedADC, T2 shine through effect).
• Chronic lesions can be differentiated from acute lesions by
normalization ofADC and DWI.
89. STIR: Short T1 (Short Tau) inversion recovery
sequence
• In STIR sequences, an inversion-recovery pulse is used to
null the signal from fat (180° RF Pulse).
• STIR sequences provide excellent depiction of bone
marrow edema which may be the only indication of an
occult fracture.
90. • STIR images are highly water-sensitive and the timing of the
pulse sequence used acts to suppress signal coming from fatty
tissues – so ONLY WATER is bright
• A combination of standard T1 images and STIR images can
be compared to determine the amount of fat or water within a
body part
• Abnormal low signal on the T1 image and abnormal high
signal on the STIR image – indicates abnormal fluid
91. • TWO TYPES OF MR ANGIOGRAPHY
– CE (contrast-enhanced) MRA
– Non-Contrast Enhanced MRA
• TOF (time-of-flight) MRA
• PC (phase contrast) MRA
MR ANGIOGRAPHY
92. CE (CONTRAST ENHANCED) MRA
T1-shortening agent, Gadolinium, injected iv as contrast
Gadolinium reduces T1 relaxation time
When TR<<T1, minimal signal from background tissues
Result is increased signal from Gd containing structures
Faster gradients allow imaging in a single breathhold
CAN BE USED FOR MRA, MRV
FASTER (WITHIN SECONDS)
93. TOF (TIME OF FLIGHT) MRA
These techniques derive contrast between stationary
tissues and flowing blood by manipulating the magnitude
of the magnetization
The magnitude of magnetization from the moving spins is
very large as compared to the magnetization from the
stationary spins which are relatively small. This leads to a
large signal from moving blood spins and a diminished
signal from stationary tissue spins. Blood vessels usually
appear bright on TOF image
2D TOF- SENSITIVE TO SLOW FLOW – VENOGRAPHY
3D TOF- SENSITIVE TO HIGH FLOW – MR ANGIOGRAPHY
94. PHASE CONTRAST (PC) MRA
• It derive contrast between stationary tissues and flowing blood by
manipulating the phase of the magnetization.
• The phase of the magnetization from the stationary spins is zero and the phase
of the magnetization from the moving spins is non-zero.
• In phase difference images, the signal is linearly proportional to the velocity
of the spins. Fast moving spins give rise to a larger signal and spins moving in
one direction are assigned a bright signal and appear white in the scan ,
• whereas spins moving in the opposite direction are assigned a dark signal and
appear black on the scan.
102. • Form of T2-weighted image which is susceptible
to iron, calcium or blood.
• Blood, bone, calcium appear dark
• Areas of blood often appears much larger than
reality (BLOOMING)
• Useful for:
– Identification of haemorrhage / calcification
Look for: DARK only
GRE Sequences (GRADIENT RECALLED
ECHO/T2 *)
103.
104. Perfusion is the process of nutritive delivery of arterial
blood to a capillary bed in the biological tissue
means that the tissue is not getting
enough blood with oxygen and nutritive elements
(ischemia)
means neoangiogenesis – increased
capillary formation (e.g. tumor activity)
PERFUSION STUDIES
105. ⚫ Stroke
Detection and
assessment of
ischemic stroke
(Lower perfusion )
Tumors
Diagnosis, staging, assessment of
tumour grade and prognosis
Treatment response
Post treatment evaluation
Prognosis of therapy effectiveness
(Higher perfusion)
APPLICATIONS OF PERFUSION IMAGING
106. CISS OR FIESTA
• FIESTA (Fast Imaging Employing Steady-state
Acquisition) is the GE name for a balanced steady-state
gradient echo sequence. Philips calls balanced-FFE
(Fast Field Echo). The equivalent Siemens product is
called CISS (Constructive Interference Steady State).
• CISS sequence uses a strong T2-weighted 3D gradient echo
technique which produces high resolution isotropic images.
• Two consecutive runs of 3D balanced steady-state free
precession with different excitation levels are performed
internally and subsequently combined. Image contrast in CISS is
determined by the T2/T1 ratio of the tissue.
107. • Tissues with both long T2 and short T1 relaxation
times have high signal intensity on CISS images.
• Due to high T2/T1 ratio, water and fat have high
signal on this sequence.
• The CISS sequence provides excellent contrast
between cerebrospinal fluid (CSF) and other
structures in the brain.
• For these reasons, CISS sequence is very useful for
evaluating structures surrounded by CSF (e.g.
cranial nerves).
