What is the difference between 4D ultrasound imaging and regular ultrasound (and 3D imaging)?
144786
4D ultrasound is 3D imagery with in real time.  I wish every person could see their child with this technology.  Especially the ones thinking about abortion. This is letting scientists see movements in a fetus as early as 8 wks!  Smiling, sucking thumbs, kicking, etc.
896529
Ultra = above, so ultrasound is sound above what you can hear.\n\nAn ultrasound machine is just a form of sonar.  It works in a similar fashion, as does radar.  Sound is sent out, some tissues can absorb it while other tissues can reflect it.  The sound is picked up and with computer processing an image can be produced.\n\nAccording to Wikipedia:  http://en.wikipedia.org/wiki/Ultrasound\n“Ultrasound is sound with a frequency greater than the upper limit of human hearing, this limit being approximately 20 kilohertz (20,000 hertz).”\n\nThe human body is mostly water so the ultrasonic waves can pass through the body into an inside cavity, like the bladder, a kidney, or a woman’s womb.  The strength can be adjusted to penetrate more tissue, but it only works well in a cavity.  The ultrasound waves can pass through tissue like sonar passes through water.\n\nIn the case of a pregnant woman the womb is filled with a fluid, ambotic fluid, that is mostly water.  The ultrasonic waves can easily penetrate this fluid, but they are reflected by the babies body inside.  This creates an outline shape with some rough outlines of the face and the limb.  Even enough definition to make out if a penis is present or not.\n\nUltrasound is considered safer than using x-rays or some other radioactive source (CT or nuclear medical scans for radioactive isotopes).  However, it has been shown that the ultrasound waves can damage the brain of a rat fetus, so ultrasound should only be used on a fetus if there is a medical reason to do so.  Just getting a picture of the fetus is unethetical.\n\nIn my case I have kidney stones and an ultrasound inspection was used to see how large they are and where they were located.  The sound isn’t focused agaisnt my head so the procedure is very safe, and much cheaper than and MRI exam is.  Also the technican can run a long scan searching for something which is more difficult to do with an MRI.\n\nThe Machine has a paddle with a vibrating membrane and a smaller sound absorbing membrane.  The skin is prepared with a gell, to make better contact with the paddle.  As the paddle is placed against the skin it vibrates the skin, and the body itself, then the vibrations are carried to the organ being inspected.  The reflected vibrations are taken in by the paddle and transferred to the machine.  As the technican moves the ultrasound paddle then they create a scan image, sort of like what a radar does.  There are seveal sound receptors (the smaller vibrating membrance) inside the paddle so a single sweep can create a larger image.  The patient doesn’t feel anything, there is no bone conduction to the ear or any other sensation.  This is another reason why it is a very safe scanning method.\n\nThe returning signals are compiled by the ultrasound machine’s internal computer and displayed as a pie shapped image on the screen.  It takes a trained technican to make sense of that image.  I didn’t understand what was on the screen during my ultrasound.  Since the paddle has audio receptors, it is easy to include one that can pick up a fetus’s heartbeat.  Also part of the heart beat sound is in the ultrasonic frequency so the machine can pick it up.\n\n“Medical sonography (ultrasonography) is a useful ultrasound-based diagnostic medical imaging technique used to visualize muscles, tendons, and many internal organs, their size, structure and any pathological lesions. They are also used to visualize a fetus during pregnancy. Ultrasound scans are performed by medical health care professionals called sonographers. Obstetric sonography is commonly used during pregnancy.\n\nUltrasound is generally regarded as a "safe test" because it does not use ionising radiation as in x-rays, nuclear medicine, or CT. But it is a form of energy, and scans should only be performed for a suitable medical indication by trained operators (sonographers). Scans performed for baby photos are considered by the profession to be unethical
763861
To be honest, I am not quite sure...but perhaps diagnostic sonography involves only an image and cardial/vascular (cardio-vascular??) involves not only an image, but doppler ultrasound.\n\nHere is an excerpt from a medical textbook, "Basic Radiology"\nby Michael Y.M. Chen, Thomas L. Pope, Jr., David J. Ott \nMcGraw-Hill, 2006\n\n"Ultrasonography\n\nDiagnostic ultrasound is a noninvasive imaging technique that uses high-frequency sound waves greater than 20 kilohertz (kHz). A device known as a transducer is used to emit and to receive sound waves from various tissues in the body. The transducer is placed against the patient's skin with a thin layer of coupling gel. This gel displaces the air that would otherwise reflect virtually all of the incident ultrasound beam. As sound travels into the patient, wave fronts spread out, diminishing the overall beam intensity. Beam attenuation also occurs secondary to partial tissue absorption with associated heat conversion. At tissue interfaces, the beam is partially reflected and transmitted. The reflected sound waves, or echoes, travel back to the transducer, are converted into electric signals, and then amplified. The amplitude of the returning wave partially depends on the degree of beam absorption. A shade of gray is then assigned to each amplitude, with strong echoes being typically assigned a shade near the white end of the spectrum and weak echoes given a shade near the black end of the spectrum. In addition, the depth of the reflecting tissue can be calculated from the known total beam travel time and the average sound velocity in human tissue (1540 meters/second). Limitations of this modality are based on its operator-dependent nature, sensitivity of equipment to slow flow, variable visualization of midline abdominal organs (pancreas) or vasculature when obscured by overlying bowel gas, and inability of sound waves to penetrate gas or bone.\n\nUltrasonography has many common applications that involve imaging of the abdomen [liver, gallbladder (Fig. 1–6), pancreas, kidneys], pelvis (female reproductive organs), fetus (routine fetal surveys for detection of anomalies), vascular system (aneurysms, arteriovenous communications, deep-venous thrombosis), testicles (tumor, torsion, infection), pediatric brain (hemorrhage, congenital malformations), breast, and chest (size and location of pleural fluid collections). In addition, ultrasound-guided interventions have been used for facilitating lesion biopsy, abscess drainage, and radiofrequency ablation."\n\n"Doppler ultrasound is used primarily to evaluate vascular flow by detecting frequency shifts in the reflected beam, utilizing a principle termed the Doppler effect. This effect occurs when a sound emitter or reflector is moving relative to the receiver of sound. Objects moving toward the detector appear to have a higher frequency and shorter wavelength, while objects moving away from the detector appear to have a lower frequency and longer wavelength. If the ultrasound beam strikes a reflector (vessel wall, heart) moving toward it, the reflected sound will have a higher frequency than the original beam. The reflected sound will be of lower frequency than the original beam if the reflector is moving away when the beam strikes it. The Doppler shift is the frequency difference between the original beam frequency and the reflected beam frequency. These frequency differences are used to calculate the corresponding flow velocities, from which a Doppler waveform, or tracing, can be generated. This tracing depicts the relationship between velocity and time and is unique to the flow pattern within the vessel. Color flow Doppler assigns colors (blue and red) to structures according to their motion toward or away from transducers. This information can be superimposed on a gray-scale image.\n\nEndoluminal sonography uses a high-frequency catheter-based transducer (9–20 MHz) to image structures beyond the lumen of
1999
Landmark Graphics Corporation and 4th Wave Imaging released ProMAX 4D, a suite of innovative processing technologies that improve 4-D seismic images. You can check out this site for more info:\n\nhttp://www.halliburton.com/news/archive/2002/lgcnws_100802.jsp?printMe
200588
In my opinion, none of the previous answers are entirely correct.  I believe you're referring to STAGE 4, rather than PHASE 4.  Cancer staging is different for different types of cancer.  Stage 4 breast cancer is different than stage 4 non-Hodgkin's lymphoma...and still different than stage 4 testicular cancer (although I think testicular staging only goes to stage 3).\n\nCancer staging is the process of finding out how far the cancer has spread.  Because each cancer has its own characteristics and usual paths of metastatis, one definitive answer for "What is stage 4 cancer?" cannot be given.\n\nFor example, a simplistic view of testicular cancer staging would be: stage 1 - cancer only in testicle; stage 2 - cancer spread from testicle to abdominal lymph node(s); stage 3 - cancer spread from testicle to abd lymph nodes, to area(s) above the diaphragm.  In contrast, non-Hodgkin's lymphoma staging would be: stage 1 - cancer in one lymph node and/or the surrounding area; stage 2 - cancer in lymph node and secondary area both on the same side of the diaphragm; stage 3 - cancer involving nodes and/or organs on both sides of the diaphragm; stage 4 - all of the above, including bone marrow involvement.\n\nThe answer you're looking for will be more definitive when you're more elaborate with your question.  :)  Also, stage 4 doesn't always mean imminent death.  My husband was diagnosed with stage 4 non-Hodgkin's Lymphoma and beat it!
296535
from what i remember 4d is when you can see behind a person as your seeing their front (back and front of their head) and 5d is someway similair to 4d but in water...i think its related to water...
445230
A diagnostic mammogram just means you have symptoms or they are doing a short term follow up for something that was seen on a previous mammogram.  If your breast is already tender and sore, it can be more painful.  But a regular 4 view mammogram is the same whether it is a screening (a patient with NO symptoms) or a diagnostic.\n\nSometimes, if an area on the mammogram is not clear or if it needs to be seen in greater detail, we do a spot compression magnification view.  These are done in the same position as a regular mammogram, but the paddle that applies the compression is smaller.  It is the size of a drink coaster (or smaller).  Because there is a smaller surface area on compression, it can be more uncomfortable.  Remember, the more compression, the clearer the image, meaning that even smaller things can be seen.  Spot compression can be thought of like this.  If you use the same pressure to push on any part of your body, it will hurt more if you use one finger instead of the palm of a hand.
470784
Because the number of slices increases while still maintaining the same coverage amount, CTDI increases.  \ne.g.) You want to scan an area of 20cm (200mm).  You decrease the slice thickness from 10mm to 5mm.  You need 40 slices instead 20, thus, increasing the dose.
651952
1st D:- Length\n2nd D:- Breadth\n3rd D:- Height\n4th D:- Texture\nIn Singapore, 4D means 4 digit. A gambling game involving 4 numbers.
246820
Sound waves are transmitted into the body and are interpretted by a computer as a 3-d image.
361656
There are various brands but probably the most common in use in hospitals is AquaSonic (link to company website below.)\n\nThe gel facilitates the transmission of sound waves from the ultrasound probe to (and thence through) the skin. If there is air under the probe, the waves are reflected off it and you can't image the tissue underneath. Even a tiny air bubble will distort the wave/reading. The technical explanation (from Wikipedia):\n\n"Ultrasonography (sonography) uses a probe containing one or more acoustic transducers to send pulses of sound into a material. Whenever a sound wave encounters a material with a different acoustical impedance, part of the sound wave is reflected, which the probe detects as an echo. The time it takes for the echo to travel back to the probe is measured and used to calculate the depth of the tissue interface causing the echo. The greater the difference between acoustic impedances, the larger the echo is. The difference between gases and solids is so great that most of the acoustic energy is reflected, and so imaging of objects beyond that region is not possible."\n\nIt's a water-based gel (probably rather like KY). Most companies have proprietary formulae so I can't say exactly what they're made of. The second link is a rather neat discussion of different types of gel.
124344
advantage-  Cheaper and smaller\nDisadvantage- poorer resolution
1055499
Scientifically speaking --\nVolume is the amount of space that a 3d object occupies.\nArea is the amount of space a 2d object occupies.\nDensity is the amount of mass of an object per unit volume.
77911
http://en.wikipedia.org/wiki/3D_audio_effect that should help you in telling all about it.
159581
There is a simple answer and a much longer, more complicated answer.\n\nThe simple answer is that the T1 and T2 spins show different tissues more clearly.  On T2-weighted images, water is very bright.  On T1-weighted images, fat is very bright.\n\nI won't go into the physics of WHY that is.  It's not that important, except to us who get excited about it.  ;)
738861
If you are talking about a 3-D rectangle,\n\nThe volume of a rectangle is height times width times depth.  \n\nYou can also use base times height if its easier.\n\nhope this helps!
969292
Virtual.\nA real image is one that can be projected, like from a movie projector.