Ultrasound Principles & Instrumentation - Orientation & Imaging Planes

[0:00]MedCram.com Well now that we understand the different types of ultrasound transducers, we need to understand the orientation of the ultrasound image in relation to the transducer. Or in other words, if I place my ultrasound transducer on a patient, what anatomic orientation do I expect to see on the ultrasound screen? And if you notice on every ultrasound transducer, there's an indicator. That indicator may be a dot as in this example. There may be a small protrusion, but nonetheless, there's some sort of marking on the ultrasound probe, and that is the transducer's indicator. This corresponds with the indicator on the ultrasound screen. In this case, a blue dot, it may be some letter or a proprietary symbol, but nonetheless, there'll be some indicator on the ultrasound screen that corresponds with the indicator on the ultrasound probe. You'll notice that this indicator is on the left side of the ultrasound screen. So how does this work? We have our patient on the left and our ultrasound screen here on the right. We're going to place the ultrasound screen indicator on the left side of the screen. So if I place my ultrasound transducer on the patient and I point the indicator towards the patient's head or superiorly, that lets me know that where the indicator is on the screen, in this case the left side, then is superior. So where the indicator is pointing corresponds with the side of the screen that the indicator is on, in this case the left. And since the indicator is pointing superiorly, the left side of the screen is superior. Then the opposite of that is true, since the opposite of the indicator is pointing inferiorly, then the right side of the screen represents inferior. That tells us what the left and the right of the screen correspond to. So now let's look at what the top and the bottom of the screen correspond to. And to do that, we have to think of our ultrasound probe as a flashlight. So if I place my ultrasound probe or my quote-unquote flashlight on the patient, where is the ultrasound beam shining from? And where is the ultrasound beam shining to? Well, in this case, the ultrasound beam is shining from the anterior of the patient toward the posterior of the patient. So then on my ultrasound screen, the near field or the top part of the screen is anterior, and the bottom part of the screen is posterior. Because that is where I'm shining my beam from and where I'm shining my beam to. So we're going to do some examples that will more solidify this concept. We'll notice that we asked ourselves two questions. And if we ask ourselves these two questions, we can always find out the orientation of the ultrasound screen. And the first question is, on my ultrasound transducer, where is the indicator pointing? And that is going to correspond with where the indicator is on the screen. And then the opposite of that will be true. So if the indicator is pointing towards the patient's right, then the left side of the screen, since that's where the indicator is, will be the patient's right. The opposite of the indicator then would be the patient's left, and that figures out what's on the left and right of the screen. The second question we need to ask ourselves then is where is the ultrasound probe shining from? And where is it shining to on our patient? If it's shining from the patient's anterior body to the patient's posterior body, then that will correspond with the top of the screen being anterior and the bottom of the screen being posterior. So now let's do some examples. All right, the first example here, we have our patient on the left, and we see that our indicator is pointing up towards the patient's head or superiorly. So that means that the left side of this screen because we have the indicator here on the left side is going to be superior, and the opposite of that then is inferior. And we see on this patient that our flashlight is shining from the anterior portion of the patient to the posterior portion of the patient. Therefore, the top of the screen is anterior, the bottom of the screen is posterior. If we put this in conventional anatomic planes, this is the sagittal plane. And this is because we're slicing the patient with the ultrasound beam in a sagittal plane. Okay, next example. We see on our patient on the left here that our indicator is pointing towards the patient's right. And our indicator on our screen is on the left side of the screen. That lets us know that the patient's right is on the left side of the screen and the opposite then, the patient's left is on the right side of the screen. And then we see that our ultrasound beam is shining from anterior to posterior again. So the top of the screen is anterior, the bottom of the screen is posterior. And therefore, this is your classic transverse or axial plane. And this is just like an axial or transverse slice on a cat scanner or MRI, where you're looking at the patient from the feet towards the head. Next example, we see that our indicator is pointing up superiorly on the patient, and that our indicator on the ultrasound screen is on the left. Therefore, the left side again is superior, and the opposite of that then is true, where the right side is inferior. And in this case, our ultrasound beam is shining from the right side of the patient toward the midline and then to the left of the patient. Therefore, the near field or the top of the screen is going to be the patient's right and the far field is going to be the patient's left. And this is a classic coronal slice from the patient's right to the patient's left. Now, we looked at the three classic imaging planes, but sometimes structures do not lie in those classic planes. An example is the gallbladder. Here we see the outline of the gallbladder, and the gallbladder does not sit in the same plane on every single person. So instead of imaging in planes, we're going to image in long and short access in relation to the structure. So this would be the long access of the gallbladder, and this would be an orthogonal plane or 90 degrees from that long access, and it's going to be the short access of the gallbladder. All right, well, that wraps up ultrasound orientation and imaging planes. This is a very important concept as you begin scanning, so if you didn't feel you caught those concepts on the first time around, please watch the video over and over again until you really feel like you've got it. Next, we'll be covering ultrasound terminology and biosafety. In this course, we are going to define ultrasound. We will discuss basic ultrasound physics. We'll touch on ultrasound biosafety and the Alara principle. We will discover different ultrasound transducers and their applications. We will look at ultrasound orientation and common ultrasound terminology. We'll explore ultrasound neurology, or the different knobs and controls that you need to know on the ultrasound machine. We will look at the ultrasound modes, we'll discuss ultrasound artifacts, and we'll finish up with a step-by-step guide on how to perform an exam on a patient.