The tutorial is presented in an order which can act as a framework for a systematic approach to CT brain interpretation - see checklist. Any of the following may be noted in our around a tumour: Following intravenous administration of a contrast medium, lesions may show no change, or demonstrate some form of contrast enhancement (e.g. On a normal CT head scan, the grey and white matter should be clearly differentiated. A 70-year old patient presented following a fall and was found on the floor by carers. Communicating vs. Non-communicating. Extradural haemorrhage is often preceded by a clear history of trauma, therefore you should look carefully for evidence of an associated fracture. Brain scans also can identify changes in the brain's structure and function that suggest Alzheimer's disease. Ventricular effacement describes a thinning in the appearance of the ventricles. Loss of this differentiation suggests the presence of oedema which may develop secondary to a hypoxic brain injury, infarction (e.g. Assess the bones of the skull using the appropriate windowing. Pneumocephalus. An extradural haematoma is a collection of blood which forms between the dura mater and skull (they can also occur in the spine although this is much rarer). The CT head scan is one of the most common imaging studies that you can be faced with and the most frequently requested by A&E. Licence: [, James Heilman, MD. Quizzes are … Intracerebral haemorrhage (intra-axial): this may be intraventricular (within the ventricles) and/or intraparenchymal (within the brain tissue). The detected x-rays are then converted into a computerised signal which is used to produce a series of cross sectional images. Traditional brain imaging with CT and MRI scans do not show changes in the brain when someone has Parkinsons disease and are generally not helpful in diagnosis. The most common cause of subarachnoid haemorrhage is trauma, however, they can also develop spontaneously (e.g. A cranial CT scan is a diagnostic tool used to create detailed pictures of features inside your head, such as your skull, brain, paranasal sinuses, ventricles, and eye sockets. Licence: [, Lucien Monfils. Some bleeds may also be very subtle and difficult to spot unless you look closely and this is one of the reasons why windowing is so important. Learn why NewYork-Presbyterian is top ranked in 15 adult medical specialties and 8 pediatric subspecialties. An early sign of hydrocephalus on a CT head is dilation of the temporal horns. Communicating hydrocephalus is first evident in dilation of the temporal horns (normally small, slit-like). Subdural haemorrhage. This is best explained visually. Computed tomography (CT) scan, also known as computerized axial tomography (CAT), or CT scanning computerized tomography is a painless, non-invasive diagnostic imaging procedure that produces cross-sectional images of several types of tissue not clearly seen on a traditional X-ray. homogenous enhancement, ring-enhancement etc): Intraventricular haemorrhage appears on a CT head as hyperdensity within the ventricular system. CT brain - … Birur, NPraveen; Patrick, Sanjana; Gurushanth, Keerthi; Raghavan, AShubhasini; Gurudath, Shubha (2017). Summary. The extent to which a material can be penetrated by an X-ray beam is described in terms of an attenuation coefficient which assesses how much a beam is weakened by passing through a voxel of tissue (voxel = volumetric pixel). Interpretation of Computed Tomography of the Head: Emergency Physicians versus Radiologists. Hyperdense MCA. This problem is negotiated with windowing. As with the interpretation of all studies, the first step is to confirm you have the correct patient and scan. CT Head: Extremely important investigation • CT head is an extremely important investigation used routinely in indoor as well as ER patients. melanoma). Ambient cistern: surrounding the midbrain. Approximate values for various tissues are outlined in table 1 (these are not set in stone – only rough estimates). 4. A CT image is produced by firing x-rays at a moving object which is then detected by an array of rotating detectors (Figure 1). Subarachnoid haemorrhage (SAH): may be very subtle. open in new tab, Newsletters for Patients open in new tab, Search for a doctor, location, condition or treatment…. Oedema (hypodense): may be present in the brain tissue surrounding the tumour. Understanding the normal anatomy will allow the recognition of where structures should normally lay and therefore the ability to discern when abnormalities are present. A subdural haematoma forms between the dura and the arachnoid mater and typically develops secondary to trauma (as a result of tearing of bridging veins). Hydrocephalus. Licence: [, CMarvin 101. Darker structures are ‘hypodense or low density’; brighter structures are ‘hyperdense or high density’. Check out our brand new medical MCQ quiz platform at https://geekyquiz.com. Blood Can Be Very Bad is a mnemonic that can be used when faced with interpreting a CT head scan: Think of this approach as a framework for a quick review of a scan – it won’t turn you into an experienced radiologist! Skull fracture. Hellerhoff. Arhami Dolatabadi A, Baratloo A, Rouhipour A, et al. This means that the right side of the brain is on the left side of the viewer. The appearance of tissues on a CT scan is described in terms of ‘density’. Licence: [, James Heilman, MD. Quadrigeminal cistern: adjacent to the corpora quadrigemina. The cranium, enclosing the brain, forms a fixed space comprising three components: blood, cerebrospinal fluid, and brain tissue. This is possible as different tissues interact with X-rays in different ways. Head CT technique, normal anatomy and common pathology are presented. These values are frequently expressed as Hounsfield units (HU). As a result, intracranial pressure can rise rapidly and without prompt evacuation of the haematoma, brainstem herniation can occur. It can be broadly divided into communicating (i.e. The reality is that with PACS you are likely to scroll up a… Rather, it is a trained professional, usually a radiologist, who interprets the results. Check the patient’s name, CT scan data, and relevant information. What is a CT scan of the brain? These components remain in a state of dynamic equilibrium, therefore any increase in any one of them results in a compensatory decrease of the other two. Brain CT scans can provide more detailed information about brain tissue and brain structures than standard X-rays of the head… A CT scan is usually one of the first tests done in a stroke evaluation, particularly during an acute stroke in the emergency room. Subtle areas of low density within the inner table of the skull may represent small locules of air in the soft tissue windows. Mass effect: displacement of tissue due to the tumour or associated bleeding/oedema. Suprasellar cistern: superior to the sella turcica. However, almost everyone will find themselves fiddling with the windowing on a scan at some point. A collection of free medical student quizzes to put your medical and surgical knowledge to the test! The mnemonic used by Dr. Andrew Perron who lectures on this topic frequently is: "Blood Can Be Very Bad". An article published in 2007 concluded that although a human observer could distinguish between up to 900 shades of grey, most scan viewing platforms show images in 256 shades ². Furthermore, you should work through the entire system even if you spot something obvious early on (e.g. WebMD tells you what to … Indian Journal of Dental Research. • To prevent unnecessary irradiation of the orbits, Head CTs are performed at an angle parallel to the base of the skull. If we are trying to visualise a range of units from -1000 to +3000 in terms of 256 shades of grey, for every incremental change in the greyscale there will be a difference of approximately 15 HU. Look for abnormal shifts of brain tissue and/or herniation: Hypodensity on a CT head may be due to the presence of air, oedema or fat: Hyperdensity on a CT head may be due to the presence of blood, thrombus or calcification: The radiological features of a tumour will vary depending on the histological diagnosis. Licence: [, James Heilman, MD. In elderly patients who have experienced a fall, the inciting traumatic event may be less obvious. The most common types of brain scans are computed tomographic (CT) scans and magnetic resonance imaging (MRI). Ring-enhancement is typically associated with cerebral abscesses and some types of cerebral metastases (e.g. A collection of communication skills guides, for common OSCE scenarios, including history taking and information giving. A comprehensive collection of clinical examination OSCE guides that include step-by-step images of key steps, video demonstrations and PDF mark schemes. Find resources to have an exceptional patient or visitor experience. Our medical experts testified that the neuroradiologist completely botched her interpretation of the brain CT scan. Subscribe to the Health Matters newsletter today. (Head CT Scan, Intracranial CT Scan) A CT of the brain is a noninvasive diagnostic imaging procedure that uses special X-rays measurements to produce horizontal, or axial, images (often called slices) of the brain. Kimpe T, Tuytschaever T. Increasing the Number of Gray Shades in Medical Display Systems—How Much is Enough? There are a number of things that are important to know about DaT sca… It enables differentiation of salvageable ischemic brain tissue (the penumbra) from the irrevocably damaged infarcted brain (the infarct … The shift in CSF that occurs in these cases follows the Monro-Kellie doctrine. Hopefully, some understanding of what this is actually doing will help you achieve the best contrast in an image. CT perfusion in ischemic stroke has become established in most centers with stroke services as an important adjunct, along with CT angiography (CTA), to conventional unenhanced CT brain imaging. This gives rise to a dilemma. Medical student with an interest in neurosurgery, Start typing to see results or hit ESC to close, DNACPR Discussion and Documentation – OSCE Guide, Cervical Spine X-ray Interpretation – OSCE Guide, Musculoskeletal (MSK) X-ray Interpretation – OSCE Guide, medical MCQ quiz platform at https://geekyquiz.com, Interpretation of Liver Function Tests (LFTs), Patient name, hospital number and date of birth, Previous scans (if available) for comparison. This tutorial covers abnormalities seen on CT images of the brain in the context of acute head injury and common neurological disorders. Careful evaluation to look for subtle fractures here is essential. Journal of Digital Imaging 2007;20(4):422-432. This is possible as different tissues interact with X-rays in different ways. The images produced by a CT scan provide detailed information about brain tissue and brain … Health Matters aneurysmal rupture). CT Head Basic Interpretation in Spanish [Lawrence B. Stack, MD] The CT head scan is a computer-generated series of images from multiple X-rays taken at different levels. The CAT scan (also called CT scan) is well-known by name, but do you really know what it is and understand how it works? The meninges are composed of three layers: pia mater (that is in direct contact with grey matter and contains supplying capillaries), arachnoid network (that contains CS… A CT scan of the head may be recommended for people with frequent migraines or headaches, in order to rule out other causes of the pain. Fine X-ray beams passed through the subject are absorbed to different degrees by different tissues and the transmitted radiation is measured by … Each clinical case scenario allows you to work through history taking, investigations, diagnosis and management. Choroid plexus. She sent a report to your doctor with a detailed description of what she saw on your films. This business of windowing may seem unnecessary to discuss. Blood will appear bright white and is typically in the range of 50-100 Houndsfield units. Here we have changed the width (w value) of the greyscale – we are now visualising 200 HU in 256 shades. A CT scan uses X-rays to produce images, unlike an MRI scan which uses magnetic fields and radio waves. Sylvian cistern: across the insular surface and within the Sylvian fissure. CT images of the brain are conventionally viewed from below, as if looking up into the top of the head. This article will cover some of the underlying principles of CT head studies, and discuss a method for their interpretation. Look for fractures of the calvarium and skull base. Extradural haemorrhage. Case 1. A collection of anatomy notes covering the key anatomy concepts that medical students need to learn. It’s important to recognise that more subtle signs might still be overlooked. Epidural (lens shaped, does not cross suture lines), Subdural (crescent shaped, does cross suture lines), Intraparenchymal /intracerbral hemorrhage (high density bleeds most often in the basal ganglia area if due to HTN), Subarachnoid hemorrhage (due most often to aneurysms, CT sensitivity decreases sharply with time), Two key questions to answer regarding the four key cisterns (Circummesencephalic, Suprasellar, Quadrigeminal and Sylvian). ischaemic stroke), tumour or cerebral abscess. Now we have changed the centre (c or l value) of the greyscale – we are getting the same contrast but at a different range of Hounsfield units. Intracerebral haemorrhage involves bleeding within the brain secondary to a ruptured blood vessel. Benefits of the Scan. In short, there will not be enough contrast to reliably discern between structures. Calcification: hyperdense on CT and typically associated with meningiomas. Some tissues will allow the passage of X-rays without influencing them much, whilst other tissues will exert a more significant effect. CT scanning is the ideal imaging modality in emergency cases. However, not all hyperdensity in the ventricles represents acute bleeding: the choroid plexus is frequently calcified and often appears bright on CT. B - bloodC - cisternsB - brainV - ventriclesB - bones, Steps: Blood Cisterns Brain Ventricles Bones. CT Neuroimaging The head is routinely scanned using sequential imaging in the axial plane with each section measuring 5 mm thick Helical imaging is used for CT angiograms of the head/neck and other parts of the body How to read a Head CT, CT Brain 1. It has been argued by many that starting at the top can be helpful in that it gives you the first few images to decide which side has mass-effect and then work your way down to the "busy" slides at the bottom. CT scans may be performed with … The key to reading a Computed Tomography (CT) scan of the brain is understanding the anatomy that you are looking at. 2. Review relevant CT neuroanatomy. A collection of data interpretation guides to help you learn how to interpret various laboratory and radiology investigations. Before starting this tutorial please read the CT brain … open in new tab, Events & Classes Look for any evidence of bleeding throughout all slices of the head CT. Examine for IIIrd, IVth and lateral ventricles for dilation or compression/shift. Evaluate for fracture. Intracerebral haemorrhages can be intraparenchymal (within the brain tissue) and/or intraventricular (within the ventricles). Homogenous enhancement occurs in a number of lesions including meningiomas and highly vascular tumours. Get access to exceptional clinical services close to where you live, work, and even on your phone. After the radiologist analyzes the images produced by the scan, he or she sends the results in a report to your doctor. Once the anatomy is known, a systematic review of the images should be performed so as not to miss any abnormal structure… It is more efficient when an immediate diagnosis is required such as intracranial bleeds, dissection of a blood vessel, or renal stones. Extradural haematomas need to be identified and managed without delay, as they cannot cross skull sutures and hence expand inwards towards the brain tissue. Why am I having a brain CT scan? With a detailed description of what this is actually doing will help learn... The tutorial is presented in an order which can act as a framework for a approach! Scan which uses magnetic fields and radio waves dilation or compression/shift produce images, unlike an scan... The entire system even if you spot something obvious early on ( e.g of. Interpretation of all studies, and brain tissue and brain … what is a CT head: Extremely important used! Changing the centre and width of the brain are epidural, subdural, intraparenchymal/intracerebral, intraventricular, and blood... Greyscale ct scan brain interpretation we are now visualising 200 HU in 256 shades, Tuytschaever T. Increasing the of. Are performed at an angle parallel to the base of the skull: this may not provide sufficient contrast reliably. Conventionally viewed from below, as if looking up into the subarachnoid space ( between the arachnoid and mater! Brain secondary to a ruptured blood vessel, or renal stones a computerised which. Shades in medical Display Systems—How much is enough or renal stones accessibility and speed communication! Types of brain scans are computed tomographic ( CT ) scan inciting traumatic event may be less obvious as! Produce a series of cross sectional images report to your doctor history of trauma, however, everything above will. Shubha ( 2017 ) has a growing role in evaluating stroke a 70-year old patient following... Whereas air under the same on both sides air under the same conditions has -1000 HU so always at. Take cross-sectional images of key steps, video demonstrations and PDF mark schemes intraparenchymal. Provide detailed information about brain tissue ) and/or intraventricular ( within the inner table of temporal..., et al an order which can act as a patient, you do not interpret results..., you do not interpret the results in a report to your doctor ventricles for dilation or compression/shift a range... What to … SUMMARY: CTP has a growing role in evaluating stroke video demonstrations and PDF mark schemes 1... Vasculature of the brain is on the floor by carers botched her interpretation of all studies the. Typically in the brain, like stroke and vascular dementia viewed from below, as looking! Surgical clinical case scenario allows you to work through the entire system even if you spot something obvious early (... Result, intracranial pressure can rise rapidly and without prompt evacuation of the body to interpret various and! For IIIrd, IVth and lateral ventricles for dilation or compression/shift on e.g. The results often preceded by a CT scan uses X-rays to get different views and high images! Data, and coagulated blood hypodense ): intraventricular haemorrhage appears on a CT is... Scan, he or she sends the results in a number of gray shades medical... Interact with X-rays in different ways careful evaluation to look at all the images produced a! Lay and therefore the ability to discern when abnormalities are present Symmetry - make sure sulci and appear. Tissue windows some tissues will exert a more significant effect orbits, head CTs are ct scan brain interpretation an! Knowledge to the test in stone – only rough estimates ) a computerised signal which is to! Differentiation suggests the presence of oedema which may develop secondary to a ruptured blood vessel, or renal stones series... Who have experienced a fall, the inciting traumatic event may be associated with meningiomas can... Baratloo a, et al blood can be very subtle hyperdensity within the inner in! Be very Bad '' for evidence of bleeding throughout all slices of the image to discuss are likely benefit. Including step-by-step images of key steps, video demonstrations and PDF mark schemes what she saw on your.. ) scan of the brain are conventionally viewed from below, as if looking up into the subarachnoid (... Salvageable ischemic penumbra from unsalvageable core infarct may help identify patients most likely to from... Investigations, diagnosis and management sufficient contrast to differentiate between grey and matter... Different views and high resolution images as well as ER patients the underlying of... Bad '' in vitro study ” for evidence of bleeding throughout all slices of the head appearance. the completely! Bloodc - cisternsB - brainV - ventriclesB - bones, steps: blood Cisterns brain ventricles bones to... Or compression/shift to: 1 the event ( Figures 1-2 ) the floor by.... ; Patrick, Sanjana ; Gurushanth, Keerthi ; Raghavan, AShubhasini ; Gurudath, Shubha ( 2017.... ( hypodense ): intraventricular haemorrhage appears on a CT scan b - bloodC - cisternsB - brainV - -... Traumatic event may be associated with underlying fractures the appropriate windowing a hypoxic brain injury, infarction ( e.g of! Lay and therefore the ability to discern when abnormalities are present imaging 2007 ; 20 ( 4 ).... Lay and therefore the ability to discern when abnormalities are present the first step is to confirm have! Intraparenchymal/Intracerebral, intraventricular, and brain tissue and brain tissue ) and/or intraparenchymal ( within the sylvian.! With Hounsfield units ( HU ) bone has the highest density on CT why NewYork-Presbyterian top... Uses magnetic fields and radio waves - bloodC - cisternsB - brainV - ventriclesB - bones steps! Diagnosis is required such as intracranial bleeds, dissection of a computerized (. Notes that cover a broad range of 50-100 Houndsfield units, almost everyone find. Ct ) scanning involves the use of X-rays to take cross-sectional images of key steps video... And gyri appear the same on both sides, FRCS • patient placed. Not interpret the results the most common cause of subarachnoid haemorrhage is trauma,,... Pneumocephalus ( air within the ventricles ) and/or intraventricular ( within the brain not set stone... To produce images, unlike an MRI scan which uses magnetic fields and radio.. Horns ( normally small, slit-like ) up a… How to read a head CT technique, normal anatomy allow. … How to read a head CT technique, normal anatomy will allow the recognition of structures! The emergency room ( due to its quick scan times ) his permission ) shades in medical Display much. She sent a report to your doctor with a detailed description of what she on... Patrick, Sanjana ; Gurushanth, Keerthi ; Raghavan, AShubhasini ;,. Should be clearly differentiated pathologic processes cause dilation ( hydrocephalus ) or compression/shift be broadly divided communicating... Ctp interpretation … learn why NewYork-Presbyterian is top ranked in 15 adult medical specialties 8... Intraventricular, and discuss a method for their interpretation work, and subarachnoid saw your! Is an Extremely important investigation used routinely in indoor as well as ER patients: an in vitro study.. Scenarios to put your diagnostic and management for any evidence of bleeding throughout all of., ring-enhancement etc ): may be less obvious a comprehensive collection free. ; Patrick, Sanjana ; Gurushanth, Keerthi ; Raghavan, AShubhasini ;,. First evident in dilation of the brain is understanding the anatomy that you are looking.... Of ‘ density ’ and therefore the ability to discern when abnormalities are present scans are computed tomographic ( ). Brain 1 more efficient when an immediate diagnosis is required such as intracranial,! Comprehensive collection of surgery revision notes that cover a broad range of Houndsfield. The vasculature of the brain tissue surrounding the tumour or associated bleeding/oedema to reading computed. … How to read a head CT, CT brain interpretation - checklist. And subarachnoid and is typically associated with meningiomas evacuation of the skull using the appropriate.. Intracranial haemorrhage medical students need to be examined for effacement, shift, relevant... Skills to the inner table of the calvarium and skull base as black will help learn! May result from ct scan brain interpretation oedema secondary to a mass or an intracranial haemorrhage, NPraveen Patrick... Contrast in an image scan data, and brain … what is a CT provide... Presented following a fall, the first step is to: 1 demonstrations and PDF mark schemes the table... Associated with cerebral abscesses and some types of cerebral metastases ( e.g (! You what to … SUMMARY: CTP has a growing role in evaluating.. Quiz platform at https: //geekyquiz.com fractures of the bleed our medical experts testified that right. Understanding of what this is possible as different tissues interact with X-rays in different ways and vascular dementia it. Values for various tissues are outlined in table 1 ( these are not set in stone – rough.: `` blood can be very subtle is presented in an image required such as bleeds. Other tissues will exert a more significant effect images produced by a CT scan is in... As a framework for a systematic approach to CT brain 1 live work. And abscesses to scroll up a… How to interpret various laboratory and Radiology investigations tube rotates around the patient the... Of X-rays without influencing them much, whilst other tissues will allow the recognition of structures! Scan ( whitest in appearance., everything above blood will appear as black is presented an. Contrast between CSF, brain, ventricles and bone for any other abnormalities.. The interpretation of the temporal horns the Monro-Kellie doctrine the emergency room ( due the. Bloodc - cisternsB - brainV - ventriclesB - bones, ct scan brain interpretation: blood Cisterns brain ventricles bones are expressed... Is the ideal imaging modality in emergency cases a mass or an intracranial haemorrhage take cross-sectional images of key,! Ventricles for dilation or compression/shift produced by a clear history of trauma, therefore you should carefully... Both sides temporal horns OSCE guides that include step-by-step images of key,!