By Doc Org
Many operational considerations for MR imaging are similar to those for CT. Differences occur because of fringe magnetic fields, radio frequency shielding, geometry of the magnet bore, and lack of known biological hazard with MR imaging. The magnet is always on, especially in an MRI that is high-filled 1.5 Tesla or higher. This is so that the cooling of the superconducting magnet can take place and maintain an effective electromagnetic field for image acquisition. If there is some sort of incident or injury that requires a "quench" or purge of the coolant in order to turn off the magnet, the liquid helium must be vented quickly and safely directly into the atmosphere. This is why MRI machines are often on upper floors of hospitals, especially older hospitals. Liquid helium is super expensive and to quench and replenish takes time and lots of money. This is why you can also find videos on YouTube and such of people trying to pry office chairs out of an MRI with two by fours and other non ferrous items.
Ignoring Standard recommendations to setup an MRI machine not only caused malfunctioning or low quality imaging, its a life hazard. There were several instances in the recent past, when people and equipment were stuck inside MRI.
Nevertheless, a patient’s condition can deteriorate during MR imaging, requiring emergency intervention. MR imaging systems can interfere with both patient monitoring and cardiopulmonary resuscitation. Appropriate architectural and administrative measures can lessen these difficulties. The long, narrow magnet bore makes it difficult to observe the patient. Locating the operating console near the axis of the magnet provides a better, although still limited, view of the patient being scanned. Fringe magnetic fields may require location of the console relatively distant from the magnet. Magnetic shielding of the video display unit in the console can allow placement closer to the magnet. The window between the magnet room and control or console room usually requires RF shielding, which is often two layers of copper screen or perforated sheet. This shielding reduces patient visibility by light attenuation and by the distracting effect of Moire patterns and reflections. These problems can be reduced by appropriate window selection and attention to lighting details. Charge-coupled device (CCD) television cameras can be operated in relatively high magnetic fields and can be quite helpful in patient monitoring. Medical personnel and/or family members can remain near the patient to monitor or reassure the patient. The magnetic field within the scanner can affect or limit the performance of patient monitoring and communication equipment. For example, the magneto-hydrodynamic effect from flowing blood distorts electrocardiograph signals. Various solutions are being developed for these problems, such as using the main magnetic field as the field for a speaker or piping in sound via airline style head phones or providing a pneumatic squeeze bulb as a call button for the patient. Interfacing these devices with external systems is sometimes difficult. The operation of patient support equipment such as respirators, and infusion pumps can be affected near some types of magnets and other equipment such as stretchers, oxygen tanks and intravenous (IV) poles may be subjected to strong attractive forces near the magnet bore. These problems and difficulties with monitoring will make some patients inappropriate candidates for MR imaging until better solutions are found. MR lmager Site Planning Page 17 Cardiopulmonary resuscitation (CPR) is severely limited adjacent to some magnets because of the possible malfunction of CPR equipment in high fringe fields and the danger of ferromagnetic objects brought by the resuscitation team being attracted toward the magnet. The screening of arriving personnel for ferromagnetic objects is, of course, impossible. The usual solution is to remove the patient, by means of a non-ferromagnetic stretcher stationed in the scan room, to an area where CPR can be carried out. This area might be equipped with an emergency cart, monitors, oxygen and suction. Coordination of this phase of the design with the hospital’s CPR committee may be helpful. Means of preventing other personnel, who have responded to the emergency, from wandering into the magnet room during the activity surrounding CPR, should be considered. Useful means include distance, doors, warning signs and administrative procedures, such as training of the CPR team or assigning a member of the MR Imaging staff to close the magnet room door. Such situations necessitate a means of emergency shut down of the magnet. Claustrophobia and other forms of anxiety may interfere with imaging as well as patient comfort. Helpful solutions include good patient preparation, communication during scanning, someone remaining with the patient during scanning, disguising the intimidating appearance of the magnet, hiding the computer room from patient view, use of warm architectural finishes, keeping the magnet room size undramatic, disguising the vault-like appearance of the RF-shielded door, and making safety procedures and warning signs as nonthreatening as possible, consistent with adequate protection. The warm appearance of carpet must be weighed against the durability and maintenance advantages of traditional floors. Controlled access to the MR lmager suite is necessary because of possible harm to people with ferromagnetic medical implants and harm to people and equipment from unrestrained ferromagnetic objects in the vicinity of the magnet. A single entrance to the suite is helpful in this regard. Provision must be made for housekeeping personnel with floor polishers, for security personnel with keys, radios and guns, and for firemen with air tanks and axes. Non-ferromagnetic mops and buckets in a special closet or a built-in vacuum cleaner with plastic implements can be supplemented by direct supervision and/or training. If a special lock on the magnet door, which is not part of the hospital master key system, is used, emergency access to the key will be required.
By Dr. Avadesh Kumar
Ultrasound scanning is an essential clinical tool which provides images of the fetal internal anatomy. Sometimes it is also referred to as sonography because it relies on high-frequency sound waves to generate cross-sectional slices through the body. A probe or transducer is coated with a scant layer of conductive gel and placed directly on the skin. It emits ultrasound waves, and the gel ensures that the waves pass smoothly via the skin. Ultrasound waves are reflected by various structures that it encounters. The time taken by the waves to return and their strength, form the foundation for interpreting details into a clear image. Sophisticated computer software conducts this portion:
Ultrasound imaging has distinct advantages such as:
It uses real-time visualization to view the organs and the fetus. It is non-invasive. It does not rely on ionizing radiation, which is harmful to the embryo. Ultrasound imaging is interactive because the operator can capture numerous viewing planes by maneuvering the probe. Ultrasound technology today enables healthcare practitioners to view internal images in 2D, 3D, 4D and even 5D. If you are planning to buy ultrasound machine the following are some key differences between 2D, 3D, 4D and 5D ultrasound images: 2D Ultrasound It is the traditional ultrasound scanning. It means the probe sends and receives ultrasound frequency waves in one plane. Waves which are reflected back are black-and-white images of the fetus in a flat plane. The ultrasound transducer Toshiba is moved across the stomach to enable numerous viewing planes. When the correct plane is found, as indicated by the image produced on the monitor, a still photography is captured and developed on film. An example of a 2D ultrasound machine is Medison X6, Siemens X150, Edan DUS60. Innovation in transducer technology has improved visualization of abnormal and normal anatomy contrast resolution including a bi-directional Doppler flow which enables enhanced vascular study. You can even look for GE Voluson portable ultrasound machine to add convenience to your medical profession. 3D Ultrasound
More advanced development of imaging technology has promoted volume data or differing two-dimensional images which are created by reflected waves at angles which differ from one another. High-speed computing software then integrates this information to create a 3D image. GE’s Volusion I creates 3D ultrasound images by combining image volume data acquisition, volume display and volume data analysis. The operator obtains volume data by, freely moving the probe with or without using position sensors, relying on mechanical sensors that are built into the probe and using matrix sensors. Data is displayed in a rendered image, tomographic mode or multi-planar format. The multi-planar format enables the operator to assess multiple 2D image planes simultaneously.
3D ultrasound technology such as the Toshiba Aplio 500 and GE Volusion E8, have many advantages over the conventional 2D ultrasound machines such as:
Virtual planes enable enhanced visualization of fetal heart structures. Better diagnosis of fetal face, skeletal and neural tube defects. This technology helps to identify structural congenital anomalies in the 18-20 week scan. Reduced time for standard plane visualization. Less dependence on operator’s experience and skill for diagnosing fetal anomalies. Recorded data is available for remote viewing. 4D Ultrasound
This ultrasound technology enables live streaming of 3D images. In other words, patients can view the live motion of the fetal valves, heart wall blood flow, etc. 4D ultrasound technology is 3D ultrasound in motion. A 3D transducer is utilized. GE’sVoluson E10 4D ultrasound machine enables you to see moving images of the various organs in the fetus. Currently, its clinical applications are still under investigation. Most people seek 4D ultrasounds for keepsake videos, a practice which is currently discouraged by some medical watchdogs.
Advantages of using 4D ultrasound include:
Shorter duration required for fetal heart screening/diagnosis Volume data storage capability for expert review, screening, remote diagnosis, and teaching Enhances parental bonding with unborn baby Promotes healthier behavior as a result of viewing the baby in real time Father’s provide more support after visualizing the baby’s movements Better identification of fetal anomalies 5D Ultrasound
Currently, Samsung is the main player in the 5D ultrasound technology arena. Their ultrasound portfolio includes theSamsung WS80A Elite.
2D ultrasound captures axial images, whereas 3D relies on volume. 4D images combine volume and time while 5D attempts to bring a new level of workflow, which borders on automation. Samsung entered the ultrasound arena after considering which exams are very time-consuming. They wanted to identify ways to assist sonographers with this process. 5D ultrasound technologies is a type of automation where you undergo a scan, and the results are auto-populated for you. The operator will receive assistance in getting more complex exams done, or the entire examination itself is semi-automated. Both should significantly improve workflow. Eventually, consistency will also improve because the process of searching through volume to locate data and how measurements are conducted is standardized. Currently, the practice is more evidence based.
Samsung’s Elite performance 5D heart application packages enable the operator to create nine standard fetal cardiac views all at once. It will help to relieve the pressure of screening and diagnosing congenital heart disease, which is a leading organ-specific defect. Samsung’sWS80A includes features such as 5D NT or nuchal translucency and 5D LB or fetal long bone. Samsung’s Elite performance package combines 5D Heart and 5D CNS aimed at the central nervous system. It displays 6 measurements which are BPD, OFD, HC, Posterior Fossa, Cerebellum, Atria lateral ventricle from 3 transverse views. Samsung’s Ws80A Elite performance package has currently received a 510(k) clearance. It debuted in the U.S. at the 35th Annual Meeting for the Society for Maternal Fetal Medicine. Source
Post your opinions
By Dr. Anmol
The CT head scan is a computer-generated series of images from multiple X-rays taken at different levels. Fine X-ray beams passed through the subject are absorbed to different degrees by different tissues and the transmitted radiation is measured by a scanning device.
The degree of absorption of X-rays is proportional to the density of the tissue through which it passes. Hounsfield units (HU) are used to measure how much of the X-ray beam is absorbed by the tissues at each point in the body. The denser the tissue, the more the X-ray beam is attenuated and the higher the number. Units are established on a relative scale with water as the reference point. Water is always 0 HU, bone is approximately 1000 HU and air is –1000 HU
Mnemonics to remember: Blood can be very bad
Blood - Blood Can - Cisterns Be - Brain Very - Ventricles Bad - Bone
Use a systematic approach to viewing the anatomical structures in the many slices prepared by the CT scanner.Interpretation
Orientation The CT slice is regarded as being viewed from the patient’s feet, so the left side of the picture as you view it is the right side of the patient. Contrast versus non-contrast Determine if scans have been taken with or without IV contrast, as contrast may mimic the presence of blood. IV contrast does not cross the normal blood brain barrier and is used if there is a suspicion of tumour, infection (e.g. abscess) or vascular abnormality (e.g. AVM or aneurysm) General review Generate a system to review all the essential features of the CT head scan (Table 38.2). Blood
Look for the presence of blood. Clues to the origin of the haemorrhage, its duration and the cause of the insult may be indicated by its position and spread. Acute haemorrhage absorbs X-rays and appears hyperdense (white) on CT scans. As the clot retracts it becomes more hyperdense over the first few hours up to 7 days; then isodense with brain over the following 1-4 weeks and finally hypodense compared with brain over the subsequent 4-6 weeks. Extracerebral (axial) haemorrhage occurring within the skull, but outside the brain Extradural haemorrhage (EDH)—biconvex lesion that does not cross suture lines; usually secondary to arterial injury. Subdural haemorrhage (SDH)—crescent-shaped blood collection that can cross suture lines; usually secondary to venous disruption of surface and/or bridging vessels. Subarachnoid haemorrhage (SAH)—haemorrhage into the CSF and cisterns secondary to aneurysms, trauma and arteriovenous malformation. Intracerebral (axial) haemorrhage occurring within the brain itself Intracerebral haemorrhage (ICH)—secondary to trauma, hypertension and haemorrhagic stroke. Intraventricular haemorrhage (IVH)—usually associated with significant trauma. Cisterns
Cisterns are collections of CSF, which surround and protect the brain. Examine each for evidence of effacement, asymmetry and the presence of blood. Circum-mesencephalic—surrounding the midbrain Suprasellar—around the circle of Willis Quadrigeminal—located at the top of the midbrain Sylvian—between temporal and frontal lobes. Brain matter
Compare the sulcal pattern (gyri) for evidence of effacement and relative volumes of the left and the right sides of the brain for asymmetry. Trace the falx through the series of scans, looking for mid-line shift secondary to compartmental mass effect. Look for inconsistencies in the grey–white differentiation (e.g. evolving embolic stroke). Patients with CVA may have a normal CT head scan on presentation with subtle oedema beginning at 6-12 hours, hypoattenuation after 24 hours and maximal oedema at 3-5 days. Identify hyperdense regions associated with blood, IV contrast or calcification. Identify hypodense regions associated with air, fat, ischaemia or tumour. Ventricles
Examine the lateral ventricles, 3rd and 4th ventricles for asymmetry, dilatation (hydrocephalus), effacement and haemorrhage. Bone
Cortical bone has the highest density on the CT scan (300–1000 HU) and is best viewed on separate bony windows when looking for evidence of fractures or tumours.
By The Doc
Looking for a Ultrasound app? SonoSite’s SonoAccess 2.0 is first interactive mobile learning application designed by FUJIFILM SonoSite. This app is for made for Radiologists and technicians with the aim of giving instant access to an extensive arsenal of clinical and case studies, image galleries, reference guides, product guides etc. This app available for all android tablets and mobiles having 4.1 or later and all apple phone/ iPad. The app is also good for medical student who wants to learn the basics.
Customize your user profile to generate a recommended list of content Download any content item for offline access
Streamlined user interaction for the most-used features. Search the entire database to quickly find the resource you need
“What’s New” feed to find content you haven’t seen before
Over 200 videos available for your training and ongoing education
Video case studies for more detailed information on clinical applications clinical image gallery with over 100 ultrasound images to reference
Download from: Play Store OR Apple Store
By Dr JP Goswami
Chest X-ray is one of the commonest OPD investigation we frequently encounter. All of us must know how to read it and interpret. Reading a chest x-ray, though looks simpler, often overlooked by us. Here is a simpler way to remember and read a chest x-ray easily.
The popular mnemonics to remember is DRSABCD. This is quite simple to understand and interpret accordingly.
D – Details about the patient and the x-ray. Why it’s important? Well, a what’s can go wrong if we interpret another patient’s x-ray for some one else. We describe details under the following sub heading.
Patient name, age / DOB, sex
Type of film – PA or AP, erect or supine, correct L/R marker, inspiratory/expiratory series
Date and time of study
R- Ripe it’s for assessing the technical quality of the image.
Rotation – medial clavicle ends equidistant from spinous process
Inspiration – 5-6 anterior ribs in MCL or 8-10 posterior ribs above diaphragm, poor inspiration?, hyperexpanded?
Picture – straight vs oblique, entire lung fields, scapulae outside lung fields, angulation (ie ’tilt’ in vertical plane)
Exposure (Penetration) – IV disc spaces, spinous processes to ~T4, L) hemidiaphragm visible through cardiac shadow.
S – Soft tissues and Bones –
Ribs, sternum, spine, clavicles – symmetry, fractures, dislocations, lytic lesions, density
Soft tissues – looking for symmetry, swelling, loss of tissue planes, subcutaneous air, masses
Calcification – great vessels, carotids
A- Airway and Mediastinum
Trachea – central or slightly to right lung as crosses aortic arch
Paratracheal/mediastinal masses or adenopathy
Carina & RMB/LMB
Mediastinal width <8cm on PA film
Hilum – T6-7 IV disc level, left hilum is usually higher (2cm) and squarer than the V-shaped right hilum.
Check vessels, calcification.
B – Breathing
Vascularity – to ~2cm of pleural surface (~3cm in apices), vessels in bases > apices
Pneumothorax – don’t forget apices
Lung field outlines – abnormal opacity/lucency, atelectasis, collapse, consolidation, bullae
Horizontal fissure on Right Lung
Pulmonary infiltrates – interstitial vs alveolar pattern
C – Circulation
Heart position –⅔ to left, ⅓ to right
Heart size – measure cardiothoracic ratio on PA film (normal <0.5)
Heart borders – R) border is R) atrium, L) border is L) ventricle & atrium
Hemidiaphragm levels – Right Lung higher than Left Lung (~2.5cm / 1 intercostal space)
Cardiophrenic and costophrenic angles – clear and sharp
Gastric bubble / colonic air
Subdiaphragmatic air (pneumoperitoneum)
E – Extras
ETT, CVP line, NG tube, PA catheters, ECG electrodes, PICC line, chest tube
PPM, AIDC, metalwork