This document summarizes a course on interpreting head CT scans for medical students. It discusses the physics of CT scanning, normal brain anatomy visible on CT, and various neurological emergencies that can be identified on head CT such as traumatic injuries like epidural and subdural hematomas as well as non-traumatic conditions like stroke and hydrocephalus. The course aims to provide students with skills to recognize important pathologies and avoid missed diagnoses when interpreting head CT scans.
presentation on ultrasound elastography-introduction ,techniques,physics,application, interpretation and future prospects.sourced from multiple articles.
Concise overview of all the information that a Medico must know for his knowledge as well as to appear for entrance exams as well as for physicians for their routine practice.
presentation on ultrasound elastography-introduction ,techniques,physics,application, interpretation and future prospects.sourced from multiple articles.
Concise overview of all the information that a Medico must know for his knowledge as well as to appear for entrance exams as well as for physicians for their routine practice.
Neuroimaging is the use of various techniques to either directly or indirectly image the structure, function of the nervous system.
Neuroimaging plays a pivotal role in the diagnosis of central nervous system (CNS) disorders.
Main modalities of neuroimaging techniques are CT scan and MRI.
This is a slideshow made essentially for undergraduate MBBS students to have a working knowledge about CT scan of brain in diagnosing common medical and surgical conditions. It includes detection of major anatomical structures in CT and prompt diagnosis of emergency conditions like head trauma and cerebrovascular accident. Last but not the least, I have also touched the areas where CT scan is not the first mode of diagnosis (like diagnosis of brain tumor and evaluation of headache).
Significance of Brain imaging in Psychiatry. Most of the major Psychiatric disorders are associated with statistically significant differences on various Neuroimaging measures, when comparing groups of patients and controls.
Primary Hemangiopericytoma in Parietal Bone: Literature Review and Case Reportkomalicarol
Hemangiopericytoma (HPC) is a tumor from
pericytes surrounding capillary walls. Most HPCs grow slowly,
but others display aggressive growth. Treatment for HPC is total
resection or resection plus adjuvant radiation.
Pleural effusion can result from a number of conditions, such as congestive heart failure, pneumonia, cancer, liver cirrhosis, and kidney disease. [1] The characteristics of the fluid depend on the underlying pathophysiologic mechanism. The fluid can be transudate, nonpurulent exudate, pus, blood, or chyle. Imaging studies are valuable in detecting and managing pleural effusions but not in accurately characterizing the biochemical nature of the fluid.
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
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
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
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.
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
Title: Sense of Taste
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 structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Anti ulcer drugs and their Advance pharmacology ||
Anti-ulcer drugs are medications used to prevent and treat ulcers in the stomach and upper part of the small intestine (duodenal ulcers). These ulcers are often caused by an imbalance between stomach acid and the mucosal lining, which protects the stomach lining.
||Scope: Overview of various classes of anti-ulcer drugs, their mechanisms of action, indications, side effects, and clinical considerations.
1. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
ABCs of Head CT Interpretation in the Emergency Department:
CT Interpretation Workshop Guide
Heather M. Prendergast, MD, MPH, FACEP
Associate Professor
Department of Emergency Medicine
University of Illinois at Chicago
I. Course Description: This session will provide medical students with a skill
set to improve their ability to interpret Head CTs. To start the session, the
physics of CT scanning will be briefly reviewed. We will move quickly
into a review of normal neuroanatomy and CT appearance, followed by a
detailed review of the role of Head CT in the management of various
neurological emergencies. The diagnoses covered will include traumatic
injuries, such as epidural and subdural hematoma, skull fracture, and
contusion, and non-traumatic conditions such as stroke, subarachnoid
hemorrhage, and hydrocephalus. Tools to avoid errors of interpretation
will be discussed.
II. Course Objectives: Upon completion of this course, participants will be
able to:
1. Discuss the physics that apply to CT scanning, including Hounsfield
numbers, windows, and frequent sources of scan artifact such as volume
averaging.
2. Describe the CT appearance of normal brain anatomy.
3. Be able to identify the pathologic conditions found on cranial CT
commonly encountered in the Emergency Department.
2. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
III. Introduction: The cranial computed tomography (CT) has assumed a
critical role in the practice of emergency medicine for the evaluation of
neurological emergencies, both traumatic and atraumatic. Despite the
immediate importance for emergency physicians to recognize intracranial
emergencies on head CT, few receive formalized training in this area during
medical school or residency.
History of CT: In 1970, Sir Jeffrey Hounsfield combined a mathematical
reconstruction formula with a rotating apparatus that could both produce and
detect xrays, producing a prototype for the modern-day CT scanner. For this
work he received both a Nobel Prize and a knighthood.
IV. X-Ray Physics: The most fundamental principle behind radiography of
any kind is the following statement: X-rays are absorbed to different
degrees by different tissues. Dense tissues, such as bone, absorb the
most x-rays, and hence allow the fewest through the body part being
studied to the film or detector opposite. Conversely, tissues with low
density (air/fat), absorb almost none of the x-rays, allowing most to pass
through to a film or detector opposite.
Conventional radiographs: Conventional radiographs are two-dimensional
images of three-dimensional structures, as they rely on a summation of
tissue densities penetrated by x-rays as they pass through the body. Denser
objects, because they tend to absorb more x-rays, can obscure or attenuate
less dense objects. Also subject to x-ray beam scatter which further blurs or
obscures low-density objects.
Computed tomography: As opposed to conventional x-rays, with CT
scanning an xray source and detector, situated 180o across from each other,
move 360o around the patient, continuously sending and detecting
information on the attenuation of x-rays as they pass through the body. Very
thin x-ray beams are utilized, which minimizes the degree of scatter or
blurring. Finally, a computer manipulates and integrates the
acquired data and assigns numerical values based on the subtle differences in
x-ray attenuation. Based on these values, a gray-scale axial image is
generated that can distinguish between objects with even small differences
in density.
Pixels: (Picture element) Each scan slice is composed of a large number of
pixels which represent the scanned volume of tissue. The pixel is the
scanned area on the x and y axis of a given thickness.
3. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
Attenuation coefficient: The tissue contained within each pixel absorbs a
certain proportion of the x-rays that pass through it (e.g. bone absorbs a lot,
air almost none).This ability to block x-rays as they pass through a substance
is known as “attenuation”. For a given body tissue, the amount of
attenuation is relatively constant, and is known as that tissue’s “attenuation
coefficient”. In CT scanning, these attenuation coefficients are mapped to an
arbitrary scale between –1000 (air) and +1000 (bone). (See Figure 1 below)
The Hounsfield numbers define the characteristics of the tissue contained within
each pixel, and are represented by an assigned portion of the gray-scale.
Windowing: Windowing allows the CT reader to focus on certain tissues on
a CT scan that fall within set parameters. Tissues of interest can be assigned
the full range of blacks and whites, rather than a narrow portion of the gray-
scale. With this technique, subtle differences in tissue densities can be
maximized.
4. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
V. Normal Neuroanatomy as seen on Head CT:
As with x-ray interpretation of any body part, a working knowledge of
normal anatomic structures and location is fundamental to the clinician’s
ability to detect pathologic variants. Cranial CT interpretation is no
exception. Paramount in head CT interpretation is familiarity with the
various structures (from parenchymal areas such as basal ganglia) to
vasculature, cisterns and ventricles. Finally knowing neurologic functional
regions of the brain help when correlating CT with physical examination
findings. Our goal is not to be a neuroradiologist, but to be familiar with a
relatively few structures, regions, and expected findings will allow for
sufficient interpretation of most head CT scans by the emergency physician.
5. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
6. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
7. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
8. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
VI. Neurological Emergencies
Building on the first portion of the workshop, we will look at the most
common traumatic and atraumatic pathological processes that are found
on emergent cranial CT scans.
Utilizing a systematic approach is one way that the clinician can ensure
that significant neuropathology will
not be missed.
Just as physicians are taught a uniform, consistent approach to reading an
ECG(rate, rhythm, axis, etc.), the cranial CT can also be broken down
into discreet entities, attention to which will help avoid the pitfall of a
9. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
missed diagnosis. One suggested mechanism to employ in avoiding a
missed diagnosis is using the mnemonic
“Blood Can Be Very Bad”. In this mnemonic, the first letter of each
word prompts the clinician to search a certain portion of the cranial CT
for pathology: Blood = blood, Can =cisterns, Be = brain, Very =
ventricles, Bad = bone.
Use the entire mnemonic when examining a cranial CT scan, as the presence
of one pathological state does not rule out the presence of another one.
Blood- Acute hemorrhage will appear hyperdense (bright white) on
Head CT. This is attributed to the fact that the globin molecule is relatively
dense, and hence effectively absorbs x-ray beams. Acute blood is typically
in the range of 50-100 Hounsfield units.
As the blood becomes older and the globin molecule breaks down, it will
lose this hyperdense appearance, beginning at the periphery and working
centrally. On CT blood will 1st become isodense with the brain (4 days to 2
weeks, depending on clot size), and finally darker than brain (>2-3 weeks).
The precise localization of the blood is as important as identifying its
presence.
1. Epidural hematoma (EDH)-
Most frequently, a lens shaped (biconvex) collection of blood, usually
over the brain convexity. EDH never crosses a suture line. Primarily
(85%) from arterial laceration due to a direct blow, with middle
meningeal artery the most common source. A small proportion can be
venous in origin. With early surgical therapy, mortality of <20% can
be expected.
10. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
2. Subdural hematoma (SDH)-
Sickle or crescent shaped collection of blood, usually over the
convexity. Can also be interhemispheric or along the tentorium.
SDH will cross suture lines. Subdural hematoma can be either an
acute lesion, or a chronic one. While both are primarily from venous
disruption of surface and/or bridging vessels, the magnitude of impact
damage is usually much higher in acute SDH. Acute SDH is
frequently accompanied by severe brain injury, contributing
to its poor prognosis. With acute SDH, overall significant morbidity
and mortality can approach 60-80% primarily due to the tremendous
impact forces involved (with the above mentioned damage to
underlying parenchyma). Chronic SDH, in distinction to acute SDH,
usually follows a more benign course. Attributed to slow venous
oozing after even a minor CHI, the clot can gradually accumulate,
allowing the patient to compensate. As the clot is frequently encased
in a fragile vascular membrane, these patients are at risk of re-
bleeding with additional minor trauma. The CT appearance of a
chronic SDH depends on the length of time since the bleed .
Subdurals that are isodense with brain can be very difficult to detect
on CT, and in these cases contrast may highlight the
surrounding vascular membrane.
11. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
3. Intraparenchymal hemorrhage (aka Intracerebral hemorrhage ICH)–
Cranial CT will reliably identify intracerebral hematomas as small as 5 mm.
These appear as high-density areas on CT, usually with much less mass
effect than their apparent size would dictate.
Nontraumatic lesions due to hypertensive disease are typically seen in
elderly patients and occur most frequently in the basal ganglia region.
Hemorrhage from such lesions may rupture into the ventricular space, with
the additional finding of intraventricular hemorrhage on CT. Hemorrhage
from amyloid angiopathy is frequently seen as a cortical based wedge-
shaped bleed with the apex pointed medially. Posterior fossa bleeds (e.g.
cerebellar ) may dissect into the brainstem (pons, cerebellar peduncles) or
rupture into the fourth ventricle.Traumatic intracerebral hemorrhages may be
seen immediately following an injury. Contusions may enlarge and coalesce
over first 2-4 days. Most commonly occur in areas where sudden
deceleration of the head causes the brain to impact on bony prominences
(temporal, frontal, occipital poles).
12. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
4. Intraventricular hemorrhage (IVH)-
can be traumatic, secondary to IPH with ventricular rupture, or from
subarachnoid hemorrhage with ventricular rupture
(especially PICA aneurysms). IVH is present in 10% of severe head
trauma. Associated with poor outcome in trauma (may be marker as
opposed to causative). Hydrocephalus may result regardless of
etiology.
13. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
5. Subarachnoid hemorrhage (SAH)-
Hemorrhage into CSF space (cisterns,convexity). Hyperdensity is frequently
visible within minutes of onset of hemorrhage. Most commonly aneurysmal
(75-80%), but can occur with trauma, tumor, AVM (5%), and dural
malformation. The etiology is unknown in approximately 15% of cases.
Hydrocephalus complicates 20% of patients with SAH. The ability of a CT
scanner to demonstrate SAH depends on a number of factors, including
generation of scanner, time since bleed, and skill of reader. Depending on
which studies you read, the CT scan in 95-98% sensitive for SAH in the 1st
12 hours after the ictus. This sensitivity drops off as follows:
95-98% through 12 hours
90-95% at 24 hours
80% at 3 days
50% at 1 week
30% at 2 weeks
14. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
The location of the SAH on a CT scan has been used by some to prognosticate
the location of the presumed aneurysm, although this has been challenged:
Anterior communicating artery aneurysm (30%): Blood in and around the
interhemispheric fissure, suprasellar cistern, and brainstem.
Posterior communicating artery aneurysm (25%): Blood in suprasellar
Cistern
.
Middle cerebral artery aneurysm (20%): Blood in the adjacent sylvian cistern
and suprasellar cistern.
Aneurysmal SAH can also rupture into the intraventricular, intraparenchymal,
and subdural spaces.
Extracranial – often overlooked. Use extraaxial blood and soft-tissue swelling to
lead you to subtle fractures in areas of maximal impact.
Cisterns- CSF collections jacketing the brain. 4 key cisterns must be examined for
blood, asymmetry, and effacement (as with increased ICP).
Circummesencephalic – ring around the midbrain
Suprasellar- (Star-shaped) Location of the Circle of Willis
Quadrigeminal- W-shaped at top of midbrain
15. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
Sylvian- Between temporal and frontal lobes
Brain- Inhomegenious appearance of normal gray and white matter. Examine for:
*Symmetry- Easier if patient’s head is straight in the scanner. Sulcal pattern (gyri)
should be well differentiated in adults, and symmetric side-to-side.
*Grey-white differentiation- Earliest sign of CVA will be loss of gray-white
differentiation (the “insular ribbon” sign). Metastatic lesions often found at gray-
white border.
*Shift- Falx should be midline, with ventricles evenly spaced to the sides. Can also
have rostro-caudal shift, evidenced by loss of cisternal space. Unilateral
effacement of sulci signals increased pressure in one compartment. Bilateral
effacement signals global increased pressure.*Hyper/Hypodensity- Increased
density with blood, calcification, IV contrast. Decreased density with
Air/gas (pneumocephalus), fat, ischemia (CVA), tumor.
Mass lesions:
Tumor: Brain tumors usually appear as hypodense, poorly-defined lesions on non-
contrasted CT scans. From the radiology literature, it is estimated that 70-80% of
brain tumors will be apparent without the use of contrast. Calcification and
hemorrhage associated with a tumor can cause it to have a hyperdense appearance.
Tumors should be suspected on a non-contrasted CT scan when significant edema
is associated with an ill-defined mass. This vasogenic edema occurs because of a
loss of integrity of the blood-brain barrier, allowing fluid to pass into the
extracellular space. Edema, because of the increased water content, appears
hypodense on the CT scan. Intravenous contrast material can be used to help define
brain tumors. Contrast media will leak through the incompetent blood-brain barrier
into the extracellular space surrounding the mass lesion, resulting in a contrast-
enhancing ring. Once a tumor is identified, the clinician should make some
determination of the following information: Location and size (intraaxial-within
the brain parenchyma, or extraaxial), and the degree of edema and mass effect (e.g.
is herniation impending due to swelling).
16. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
Abscess: Brain abscess will appear as an ill-defined hypodensity on non-contrast
CT scan. A variable amount of edema is usually associated with such lesions and,
like tumors, they frequently ring-enhance with the addition of intravenous contrast.
Ischemic infarction:
Strokes are either hemorrhagic or non-hemorrhagic. Non-hemorrhagic infarctions
can be seen as early as 2-3 hours following ictus (if you count ultra-early changes
such as the “insular ribbon sign”), but most will not begin to be clearly evident on
CT for 12-24 hours. The earliest change seen in areas of ischemia is loss of gray-
white differentiation. This can initially be a subtle finding. Edema and mass effect
are seen in association with approximately 70% of infarctions,
and is usually maximal between days 3 and 5.
17. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
Lacunar infarctions are small, discreet non-hemorrhagic lesions, usually secondary
to hypertension and found in the basal ganglia region.
Ventricles - Pathologic processes cause dilation (hydrocephalus) or
compression/shift. Communicating vs. Non-communicating. Communicating
hydrocephalus is first evident in dilation of the temporal horns (normally small,
slit-like). The lateral, IIIrd, and IVth ventricles need to be examined for
effacement, shift, and blood.
18. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
Bone - Has the highest density on CT scan (+1000 Hounsfield units). Note soft
tissue swelling to indicate areas at risk for fracture.
Skull fracture:
Making the diagnosis of skull fracture can be confusing due to the presence of
sutures in the skull. Fractures may occur at any portion of the bony skull. Divided
into nondepressed (linear) or depressed fractures, the presence of any skull fracture
should increase the index of suspicion for intracranial injury. The presence of
intracranial air on a CT scan means that the skull and dura have been violated at
some point. Basilar skull fractures are most commonly found in the petrous ridge
(look for blood in the mastoid air cells). Maxillary/ethmoid/sphenoid sinuses all
should be visible and aerated: the presence of fluid in any of these sinuses in the
setting of trauma should raise suspicion of a skull fracture.
19. FERNE / EMRA 2009 Mid-Atlantic Emergency Medicine Medical Student Symposium:
ABCs of Head CT Interpretation; Heather M. Prendergast MD, MPH.
Summary:
Cranial computed tomography is integral to the practice of emergency medicine,
and is used on a daily basis to make important, time-critical decisions that directly
impact the care of ED patients. An important tenet in the use of cranial CT is that
accurate interpretation is required to make good clinical decisions. Cranial CT
interpretation is a skill, like ECG interpretation, that can be
learned through education, practice, and repetition.
Acknowledgement: Special thanks to Andrew D. Perron, MD, FACEP and Brian
A. Stettler, MD, FACEP .