POCUS Scan Shift Intro

Transcript

• 00:00Hey there. Thanks for your
• 00:02interest in doing a scanning
• 00:03shift with us in the
• 00:04QDR FAQD.
• 00:05We thought it'd likely be
• 00:06useful to have, an introductory
• 00:09lecture provided before your shift
• 00:11so you can have a
• 00:12little bit of background information
• 00:13to use as a guide,
• 00:15when you're doing your hands
• 00:16on scanning with us on
• 00:18Shift. And without further ado,
• 00:20we'll go on to the
• 00:21next slide.
• 00:23So this intro presentation,
• 00:25hopefully, you'll be able to
• 00:26view for your scanning shift,
• 00:28and, it'll give you a
• 00:30a brief introduction to some
• 00:32key concepts that you're gonna
• 00:33need to be familiar with
• 00:34in in order to,
• 00:36be good at getting images
• 00:37and interpreting the images on
• 00:39the screen. So
• 00:40we'll have to delve into
• 00:41a little bit and some
• 00:42basic ultrasound physics.
• 00:45We're gonna talk about scanning
• 00:46concepts that are related to
• 00:47the type of code that
• 00:48you use, you refer to
• 00:50as a transducer,
• 00:52orientation on the screen,
• 00:55some function some functionalities such
• 00:57as, color Doppler,
• 00:59depth gain, things like that.
• 01:01And NOBOLOGY is an idea
• 01:03of,
• 01:04all these different functions,
• 01:05as it pertains to your
• 01:06particular machine.
• 01:08This is something that is
• 01:09often the rate limiting step,
• 01:11for,
• 01:13sonologists or physicians who are
• 01:14using ultrasound
• 01:15to get comfortable
• 01:17at doing,
• 01:18clinical care studies.
• 01:20And,
• 01:21you know, do a little
• 01:22bit of nature. I'm trying
• 01:23to keep this short for
• 01:23you guys. There's tons of
• 01:25other resources you can tap
• 01:26into. Focus Atlas, five Minute
• 01:28Sono, additional podcast, picture video
• 01:31based,
• 01:32teaching materials. And,
• 01:35Lillian as well, has, some
• 01:37case based ultrasound.
• 01:52So, you know, our goals
• 01:53for when we do the
• 01:54scanning test together is just
• 01:56spend a little bit time
• 01:57to to teach how to
• 01:58perform
• 01:59a quality clinical ultrasound scans.
• 02:03And it's nice to have
• 02:04a dedicated time for us
• 02:05to do this so we
• 02:06don't have complete interest,
• 02:08with other clinical care needs
• 02:09that are happening simultaneously.
• 02:11So we can really spend
• 02:12the time to to go
• 02:13over the approach to
• 02:15patient, how
• 02:17to integrate family members, and
• 02:19some tricks to make things,
• 02:21a little bit easier and
• 02:22and smoother for, for the
• 02:24students.
• 02:26We talk a lot about,
• 02:27what our roles,
• 02:29in terms of binary yes
• 02:30or no questions,
• 02:32when we're doing more percent
• 02:33of the bedside. So if
• 02:35you're going to dominant trauma
• 02:36patient,
• 02:37yes or no is a
• 02:38big fluid in the abdomen,
• 02:40but,
• 02:42patient that you're concerned about
• 02:43undifferentiated
• 02:44shock, yes or no is
• 02:46the cardiac function preserved.
• 02:49And so that really is
• 02:50is a unique
• 02:54aspect of chronic care ultrasound,
• 02:56which, differs from radiology ultrasound.
• 02:59We tend to be a
• 02:59little more in-depth and in
• 03:00detail in terms of their
• 03:02scope and the questions that
• 03:03they're answering.
• 03:06So just to get on
• 03:07my ultrasound here
• 03:09for a moment, there's,
• 03:11multiple advantages,
• 03:12to ultrasound sort of relative
• 03:14to other diagnostic
• 03:16and diodes like X rays
• 03:17and and the CT scans
• 03:18and even on the line.
• 03:20So,
• 03:21our point of view at
• 03:22ultrasound is a very dynamic
• 03:23study. So you're looking at
• 03:25objects and organs in two
• 03:26planes. If everything we want
• 03:28to image, we have an
• 03:29object of interest. We wanna
• 03:31get get an image in
• 03:32perpendicular
• 03:33plane, so we say a
• 03:34long axis and a short
• 03:35axis plane.
• 03:37Obviously, ultrasound doesn't, employ any
• 03:39radiation, so it's safe for
• 03:40patients.
• 03:42We could do it serially
• 03:43so you can
• 03:45check,
• 03:46progression of illness with point
• 03:47four zero percent on two
• 03:48different points in time.
• 03:51It's fairly painless.
• 03:52There's been tons of studies
• 03:54on fracture literature with twenty
• 03:55four percent been applied
• 03:57with pain face scores and
• 03:59and if you use enough
• 04:01gel and use appropriate techniques,
• 04:03you really should not be
• 04:04causing
• 04:05any additional pain.
• 04:07And it's certainly something that
• 04:08does not require sedation or
• 04:09should not require sedation in
• 04:11order to be performed.
• 04:14And, and finally, again, sort
• 04:16of,
• 04:17it's repeatable. So,
• 04:19if if, repeatable not only
• 04:21by a different operator or,
• 04:23you say, a synergist,
• 04:25but it's
• 04:26easy to repeat at a
• 04:27different point in time,
• 04:29having machine at the ready
• 04:30of the dead cell. So
• 04:32it's really great and it
• 04:33adds a lot of really
• 04:34important information to the clinical
• 04:36picture in many cases.
• 04:39So the questions you always
• 04:40are gonna ask yourself is
• 04:41where was an ultrasound done?
• 04:43Is it done by
• 04:45a clinician at the point
• 04:46of care, a clinician who's
• 04:48who's likely taking care of
• 04:49the patient?
• 04:50Or is it a technician
• 04:51performed or a radiology performed
• 04:53ultrasound done with diagnostic imaging
• 04:55suite? And then who's doing
• 04:57it? Well, ultrasound's unique is
• 04:59that it's we say it's
• 05:00very operator dependent. So even
• 05:02even
• 05:02within a certain,
• 05:04application. So let's take the
• 05:06appendix, for example.
• 05:07We can have two,
• 05:10skilled
• 05:12ultrasound performers,
• 05:14and one,
• 05:15of the two has a
• 05:16higher,
• 05:19accuracy in terms of appendix
• 05:21identification
• 05:22and,
• 05:23ability to interpret surrounding structures
• 05:26and things like that. So
• 05:27even amongst,
• 05:28ourselves as, immunosuppressive medicine,
• 05:31physicians
• 05:33and even in in,
• 05:34the radiology
• 05:35and environment, the the operator
• 05:37is gonna make a difference.
• 05:39So it's very different than,
• 05:41putting a plate on somebody's
• 05:43back and shooting a picture
• 05:45like what they do for
• 05:46radiography for x rays. So
• 05:49so very important to to
• 05:50be aware that ultrasound is
• 05:52an operator dependent modality.
• 05:54And then why is the
• 05:55ultrasound being done? So where
• 05:56is it done? Who's doing
• 05:57it? Are you doing this
• 05:59as a as a diagnostic?
• 06:00And if show and if
• 06:01so, at the point of
• 06:02care, it should really be
• 06:02a yes or no question,
• 06:04for the most part. And
• 06:05then there's times where ultrasound
• 06:08is just, a necessary part
• 06:09of of clinical care because
• 06:11it's safer.
• 06:12It's safer, when it comes
• 06:13to procedures, and it, has
• 06:15been shown time and time
• 06:16again to increase success rates
• 06:18of prescription procedures.
• 06:21So let's get into what
• 06:23you're looking at on the
• 06:24screen. How are the images
• 06:25created by either a handheld
• 06:27device or a more standard
• 06:29sort of ultrasound,
• 06:32machine? So
• 06:34what what happens is you
• 06:35have
• 06:36everything starts with the transducer.
• 06:38So
• 06:39the the machine sends an
• 06:40electrical signal, so energy
• 06:43is tran transmitted,
• 06:45to the probe, to the
• 06:46transducer,
• 06:48and these these probes are
• 06:49tightly packed with crystals. And
• 06:52so that that electricity,
• 06:53that that current,
• 06:55what it does is it
• 06:56it causes vibration
• 06:58of these crystals at a
• 06:59very high frequency,
• 07:01hence the name ultrasound.
• 07:04So the sound signal
• 07:05at that point is sent
• 07:07to a tissue.
• 07:08In this case here you
• 07:09have,
• 07:11a cardiac
• 07:12structure.
• 07:13And depending on the tissue
• 07:15density and some properties, how
• 07:17fluid filled it is,
• 07:20there is an interaction between
• 07:23the tissue
• 07:24and the probe.
• 07:26And,
• 07:27there's two concepts,
• 07:29that come into play. So
• 07:30there's,
• 07:32attenuation, which is loss of
• 07:34signal energy
• 07:35and there's impedance, which is
• 07:37reflection
• 07:38of ultrasound
• 07:39back to the to the
• 07:40probe.
• 07:42And a combination of,
• 07:44these two properties of ultrasound,
• 07:47the computer,
• 07:48is going to generate an
• 07:49image. It's going to be
• 07:50a grayscale image
• 07:52and,
• 07:53with knowledge of important
• 07:56concepts, of general concepts that
• 07:57we're gonna go into,
• 07:59you will be able to
• 08:00say, okay, this image that
• 08:02is dark on the
• 08:04ultrasound screen is because it's
• 08:06a fluid filled structure
• 08:07because due to due to,
• 08:10full attenuation
• 08:12and lack of impedance.
• 08:15So let's look at these
• 08:16two properties of ultrasound transmission
• 08:19one at a time.
• 08:20The first is attenuation.
• 08:22So attenuation is essentially the
• 08:23loss of signal energy.
• 08:26As as ultrasound
• 08:28goes through a certain object
• 08:29or structure,
• 08:31it's gonna,
• 08:32lose the amount of signal
• 08:33that it can transmit
• 08:35deep to that structure.
• 08:37So you have a
• 08:38a less defined,
• 08:41sort of image on the
• 08:43screen essentially over what happened.
• 08:45Now the amount of attenuation
• 08:47is gonna be different depending
• 08:48on the
• 08:50makeup, the composition of the
• 08:51structure that the beam is
• 08:52going through.
• 08:54But, you can almost always,
• 09:00imagine that there's some degree
• 09:02of attenuation that's gonna exist.
• 09:04That's why the images at
• 09:06the top half of the
• 09:07screen are always crisper and
• 09:08nicer than than those at
• 09:10the bottom part of the
• 09:11screen.
• 09:12And then the other property
• 09:13of ultrasound is impedance. So
• 09:15impedance has to do with,
• 09:18tissue density and reflection
• 09:20of the ultrasound being back
• 09:21to the transducer.
• 09:23So in this case with
• 09:24bone, which has high high
• 09:26impedance
• 09:27property, the ultrasound
• 09:29reflects off the bone and
• 09:31back to the transducer,
• 09:32and the machine cannot generate
• 09:34an image deep to the
• 09:35bone. So everything goes dark
• 09:38behind tissues that have high
• 09:40impedance,
• 09:41and we we do call
• 09:42that, a certain,
• 09:45artifact referred to as posterior
• 09:48acoustic
• 09:50shadow.
• 09:53So in this light, ultrasound
• 09:54is essentially the same as
• 09:56marine life with echolocation,
• 09:59and I like to bring
• 10:00up this example to back
• 10:01home the point that the
• 10:03water
• 10:04or fluid filled structures are
• 10:06excellent
• 10:07transmitters of ultrasound.
• 10:08So,
• 10:10when a, say, an orca
• 10:12or a porpoise or a
• 10:13dolphin,
• 10:16sends an ultrasound signal
• 10:18in in the ocean through
• 10:19their echolocation
• 10:20mechanism.
• 10:22That signal is gonna continue
• 10:24to travel until it hits
• 10:25an object.
• 10:27And then based on the
• 10:28distance
• 10:29of that object,
• 10:31to the to the marine
• 10:32life
• 10:33and potentially the size
• 10:35of that object or multiple
• 10:37objects.
• 10:38The,
• 10:40marine life mammal will get
• 10:41a sense of,
• 10:43predator versus prey
• 10:45and then how far that
• 10:46they would have to travel
• 10:48to, reach
• 10:49that that object that's in
• 10:51front of them.
• 10:52Or perhaps in some cases,
• 10:54whether how far,
• 10:56the object could make they
• 10:58pose potential risk to their
• 11:00livelihoods so so that they
• 11:02can react in a timely
• 11:03manner.
• 11:04So,
• 11:05it's it's a great example
• 11:07of how
• 11:08there is very little attenuation
• 11:11of ultrasound and fluid filled
• 11:12structures, and we we talk
• 11:14about this a a lot,
• 11:16when we're imaging
• 11:18when we wanna see,
• 11:21organs that are potentially deep
• 11:23in the pelvis. So a
• 11:24common one would be workups
• 11:25for ovarian pathology, ovarian torsion.
• 11:28If we're doing trans abdominal
• 11:30ultrasound, we wanna have a
• 11:31nice fluid filled bladder
• 11:34so that the ultrasound beam
• 11:35can be
• 11:37well,
• 11:38transmitted to the pelvic structures
• 11:40to get a good look
• 11:41at the fluid piece.
• 11:45And here we have one
• 11:46last slide just to,
• 11:48once again go over this
• 11:50idea of ultrasound transmission.
• 11:52And when we talk about
• 11:53transmission, we are essentially asking
• 11:55ourselves,
• 11:56how well is my ultrasound
• 11:58being penetrated through the tissue?
• 12:01This has to do with
• 12:02the composition of the tissue.
• 12:03So if you have a
• 12:04fluid filled structure,
• 12:06you have excellent transmission, a
• 12:07nice fluid filled, nice nicely
• 12:10filled bladder
• 12:11is gonna act as an
• 12:12acoustic window
• 12:13so that the ultrasound can
• 12:15visualize structures deep to it,
• 12:16such as the ovaries, when
• 12:17you read about a very
• 12:18important phthalmoidic system or ovarian
• 12:21biology.
• 12:24When you have,
• 12:26a structure
• 12:27with high impedance,
• 12:29there's either very poor transmission
• 12:32behind that,
• 12:34object or sometimes, in fact,
• 12:36no transition.
• 12:37And then you have air.
• 12:40Air is actually the enemy,
• 12:42for ultrasound.
• 12:43So
• 12:44in terms of the appearance
• 12:46of ultrasound
• 12:47as it crosses,
• 12:48an airfield structure,
• 12:50you really cannot delineate,
• 12:53any crispness on the screen
• 12:55at all.
• 12:56And for air essentially does
• 12:58is it causes scatter
• 12:59of ultrasound beam.
• 13:01So air can cause a
• 13:03very bright or hyper echoic
• 13:05appearance
• 13:06to the image,
• 13:07and it can,
• 13:08and and what it will
• 13:09do is it will give
• 13:10you a
• 13:12very
• 13:13poorly defined,
• 13:17picture on the screen.
• 13:22Alright. So let's apply this
• 13:23these concepts of ultrasound transmission
• 13:25to an actual still image.
• 13:27In this case, I will
• 13:28let you know this is
• 13:29a, long access,
• 13:31longitudinal ultrasound in the midline
• 13:34of a pregnant patient.
• 13:36You can see that,
• 13:38over the bladder, because it's
• 13:40a nice fluid filled structure,
• 13:42there's no attenuation
• 13:43to ultrasound. So you can
• 13:45actually see,
• 13:47structures deep to it. In
• 13:49this case, there's the vaginal
• 13:50stripe, which is the landmark
• 13:52that lets us know that
• 13:53we're at the midline,
• 13:56of this trans transpiled loop.
• 13:59And then if you think
• 14:00about the uterus, look at
• 14:01how the the,
• 14:03fundus portion
• 14:05is sort of well delineated
• 14:06with the gestational sac, and
• 14:08also you can get a
• 14:09sense here
• 14:10of a fetal pull right
• 14:12there.
• 14:14So the ultrasound transmission here
• 14:16may be a slightly little
• 14:17bit different, so more attenuation
• 14:19deep to the structures.
• 14:20So you don't see as
• 14:21crisp of the margin of
• 14:22the posterior biliary uterus like
• 14:24you you do anteriorly.
• 14:27And guess what's behind the
• 14:28uterus? Well,
• 14:30it's mostly bowel, and it's
• 14:31probably bowel that's filled with
• 14:33air
• 14:34because we're not seeing anything.
• 14:35Everything looks very indistinct. And
• 14:37that makes sense based on
• 14:40the ultrasound
• 14:41interaction with air. So
• 14:44back here, even though there's
• 14:46intestines and there's actual anatomy,
• 14:48we're not seeing anything on
• 14:50the screen because bowel gas
• 14:52causes ultrasound,
• 14:54being to scatter. And you
• 14:55just have a lot of
• 14:56white the right,
• 14:59enhancement of of the the
• 15:01computer screen, and so you're
• 15:02not really seeing anything other
• 15:03than that.
• 15:08Okay. So here we have
• 15:10a a quiz,
• 15:12named that phone.
• 15:15And so how do we
• 15:15know what we are looking
• 15:17from?
• 15:18So one of the things
• 15:19we always wanna keep an
• 15:20eye out when we're reviewing
• 15:22clips and also when you're
• 15:24performing ultrasound scans is the
• 15:26settings.
• 15:27So here's a bit of
• 15:28a clue.
• 15:30This happens to be an
• 15:32ultrasound of lung tissue.
• 15:35So in terms
• 15:37of meaning a bone, what
• 15:38bone would be seen,
• 15:40in front of,
• 15:43lung? Well, that would be,
• 15:44of course, your ribs. So
• 15:46here you see the top
• 15:49of the rib
• 15:50in
• 15:51short axis.
• 15:52And as you can see,
• 15:55ultrasound cannot penetrate
• 15:57deep to the rib, so
• 15:58everything here is dark,
• 16:01dark.
• 16:02And so that is this
• 16:03artifact that we have alluded
• 16:05to as, posterior acoustic enhancement.
• 16:07So you know that this
• 16:08is a red hue.
• 16:11The other interesting sort of
• 16:12finding is that we typically
• 16:14will see the
• 16:16plural be a very bright
• 16:18line in between the blue
• 16:19spaces.
• 16:21So in this case,
• 16:24not only do you sort
• 16:25of
• 16:26see separation
• 16:28of the plural right here,
• 16:30Looks like there's one line
• 16:31and another line.
• 16:34Do a small little fluid
• 16:35collection there, a small little
• 16:36fluid effusion.
• 16:38But this is actually a
• 16:39patient who has pneumonia by
• 16:40one ultrasound
• 16:42in the right posterior field.
• 16:45We said briefly that air
• 16:47gives no image, so just
• 16:50a
• 16:51essentially artifact.
• 16:53And,
• 16:56we can spend an entire
• 16:57hour talking about lung ultrasound,
• 16:59but essentially this jaggedness here
• 17:02of the,
• 17:05the tissue of this lung
• 17:06tissue
• 17:07is an appearance that you
• 17:09would see with a subfloor
• 17:10consolidation.
• 17:13And there's some other findings
• 17:14that in addition to that
• 17:16shred sign, you have these
• 17:17sort of bright, echogenic appearances,
• 17:21in within
• 17:23a tissue
• 17:24that we shouldn't be seeing.
• 17:25We we shouldn't be seeing
• 17:27a distinct sort of organ
• 17:28appearing tissue up there under
• 17:31the flora because,
• 17:33lung, because since it's when
• 17:34it's health healthy as air
• 17:36filled,
• 17:37does not give off any
• 17:38appearance on the lurchaser. You
• 17:40just see the liberation artifact,
• 17:42which we call a lungs.
• 17:43But, a little bit ahead
• 17:45of,
• 17:47where where we are right
• 17:48now in terms of this
• 17:49lecture,
• 17:51but I'm hoping you can
• 17:53get a good sense of
• 17:55rib bone here,
• 17:56ultrasound hitting the rib bone.
• 17:59It looks bright and echogenic.
• 18:02There's high impedance, there's no
• 18:03transmission, so you get this
• 18:05complete
• 18:06acoustic shadowing,
• 18:08deep to that structure.
• 18:11Alright. So when we're talking
• 18:12about what transducers to choose,
• 18:15the transducers are the former
• 18:16term for a ultrasound probe.
• 18:19There's essentially three choices. You
• 18:21have,
• 18:23a linear probe, which has
• 18:24a nice flat footprint
• 18:26here,
• 18:27creating superficial structures. You have
• 18:30a curvilinear
• 18:31flow.
• 18:33There's a curved footprint, which
• 18:35is better to look for
• 18:36deeper structures.
• 18:37And you have a
• 18:38type of curvilinear flow, called
• 18:40a phased array flow, which
• 18:42is a cardiac,
• 18:44together between
• 18:45grid spaces and get a
• 18:46nice
• 18:48view of the car structures
• 18:49when you're doing a focus
• 18:51product focusing.
• 18:53So when we talk about
• 18:54code selection or or cancellation
• 18:56selection, you're gonna pick a
• 18:58a probe,
• 19:00which is gonna fit your
• 19:02needs. So the trade off
• 19:03between a curvilinear,
• 19:05low frequency
• 19:06and a
• 19:08linear high frequency
• 19:09is resolution
• 19:11to depth. Or or depth
• 19:12is how how much penetration
• 19:14can the ultrasound be achieved.
• 19:17So the linear probe, the
• 19:18higher frequency probes are able
• 19:20to,
• 19:22achieve a greater resolution,
• 19:23a higher level of detail
• 19:25for superficial
• 19:26structures at the trade off
• 19:28of
• 19:29depth, the ability to penetrate,
• 19:31deep to deeper structures
• 19:33and vice versa with the
• 19:35curvilinear probes and and the
• 19:36phased array for these curvilinear
• 19:38probes. So with these probes,
• 19:39you're gonna sacrifice resolution
• 19:42for your ability to penetrate
• 19:43deeper structures.
• 19:45So intra abdominal
• 19:47examinations, the classical being trauma,
• 19:51focus assessment of synoptic and
• 19:52trauma. So the FAST exam,
• 19:54you're gonna perform
• 19:55with permalinear
• 19:56or low frequency plates.
• 19:59Alright. So there's two scanning
• 20:01planes to be familiar with.
• 20:03And there it's important because
• 20:04we have convention in terms
• 20:06of how we image
• 20:11patients,
• 20:12so that our pattern recognition
• 20:13could be consistent with those
• 20:14patients.
• 20:16So we will use in
• 20:17the long axis of the
• 20:19sagittal or longitudinal
• 20:20axis,
• 20:21plane, we will use the
• 20:23convention of having the indicator,
• 20:24which is usually like a
• 20:25little,
• 20:27notch or line on the
• 20:29probe itself
• 20:31towards the head of the
• 20:32patient.
• 20:32So
• 20:33the indicator always faces the
• 20:35head
• 20:36when we're,
• 20:38doing a longitudinal access
• 20:41scan. And this is gonna
• 20:42correlate with the monitor this
• 20:44way. You're gonna have head
• 20:46here.
• 20:47You're gonna have the top
• 20:48part of the patient. You're
• 20:50gonna have the bottom part
• 20:50of the patient, and you're
• 20:51gonna have feet.
• 20:55And when we're doing the
• 20:56transverse,
• 21:00orientation,
• 21:01the convention is always gonna
• 21:03be for that indicator
• 21:05to be to the right
• 21:07of the body. So indicator
• 21:09to the right,
• 21:10again it's going to be
• 21:11a little notch or some
• 21:12sort of mark on
• 21:14the right side of the
• 21:15patient,
• 21:16and these are almost like
• 21:17your cross section,
• 21:19your CT scan cross sections
• 21:20where you have,
• 21:22indicated to the right, you
• 21:24have the right kidney
• 21:25here,
• 21:26and on the screen, the
• 21:28right kidney is gonna appear,
• 21:31as you're looking at the
• 21:32screen, it's actually the the
• 21:33left side of the screen,
• 21:35but it's the right side
• 21:36of the patient.
• 21:39So
• 21:41once you get this down
• 21:42visually,
• 21:43spatially in your in your
• 21:45brain,
• 21:46a a few times, it's
• 21:48a very easy concept to
• 21:49to tuck away.
• 21:52And then we we will
• 21:53use some scanning lingo. So
• 21:55we will slide, rock, sweep,
• 21:56and fan the probe.
• 21:58Sliding means you're just bringing
• 22:01the
• 22:02transducer
• 22:03back and forth along the
• 22:05y axis or the the
• 22:06long axis of a object.
• 22:09And when you walk,
• 22:11along this y axis line,
• 22:13you would essentially keep the
• 22:14hand still
• 22:15and just sort of swivel
• 22:18the probe
• 22:19back and forth.
• 22:20Right? Because remember the, image
• 22:22that we're gonna generate is
• 22:23gonna have to do with
• 22:24the how
• 22:26perpendicular, how straight that ultrasound
• 22:28beam is to a certain
• 22:29structure. So you may have
• 22:31a gallbladder,
• 22:32for example, just put in
• 22:33an example. You may have
• 22:34a gallbladder here,
• 22:36but if you don't rock
• 22:37the probe
• 22:38just right
• 22:39to have it,
• 22:41perpendicular, you're not gonna see
• 22:43it. It's not that it's
• 22:44not there, it's
• 22:46right there nearby hiding out.
• 22:48But sometimes some small motions
• 22:51of the hand with with
• 22:52these maneuvers
• 22:53is what you need to
• 22:54do in order to get
• 22:55a good image on your
• 22:56screen.
• 22:56So we have, the sliding
• 22:59and and the rocking, which
• 23:00is,
• 23:01essentially along
• 23:03the,
• 23:04a y axis plane or
• 23:05longitudinal axis plane. And then,
• 23:08sweeping would be in short
• 23:10access. So say you have
• 23:11a say you have a
• 23:12a blood vessel here, and
• 23:14it's you're you're sort of
• 23:15forcing the probe. You're sweeping
• 23:17all the way up and
• 23:18down the vessel
• 23:19to see it in its
• 23:20entirety.
• 23:21And on the screen, you're
• 23:22actually gonna see it as
• 23:23a circle
• 23:24when you're when you're imaging
• 23:26the vessel,
• 23:27the representative is typically going
• 23:29this way,
• 23:30and you're gonna see circle,
• 23:32circle, circle on the screen
• 23:35as you sweep up and
• 23:36down. And then fanning, we
• 23:37do a lot of fanning
• 23:38with our our FAST exams.
• 23:40So, again, the the it's
• 23:41a swivel motion
• 23:42in the short access,
• 23:44cut
• 23:45with,
• 23:46the the essentially, your your
• 23:48hand isn't moving up or
• 23:49down on the patient's body.
• 23:51Your hand is staying still,
• 23:52then you're sort of fanning
• 23:54or rotating like this, rotating
• 23:56the fold.
• 24:00Down. So get a good
• 24:02look at that at that
• 24:03structure that we're interested in.
• 24:07Alright. So let's look at
• 24:08this,
• 24:09another way. So you have,
• 24:11your indicators, which have a
• 24:12notch. Our our probes have
• 24:14a a t notch.
• 24:16And when we image,
• 24:18an individual in a transverse
• 24:20plane or the short axis
• 24:21plane,
• 24:22the indicator is gonna point
• 24:24towards the right of the
• 24:25patient, which is here in
• 24:26this gingerbread line, the right
• 24:28of the patient.
• 24:29And you're gonna actually see
• 24:30the indicator,
• 24:33appear
• 24:34on the left side of
• 24:35the screen as you're looking
• 24:36at the screen.
• 24:37So this is a convention
• 24:39for transverse. You have a
• 24:41fluid filled structure with
• 24:43a balloon catheter inside of
• 24:45it. This is a child
• 24:46with urine retention that had
• 24:47to have a fully, catheter
• 24:49placed, and that's what the
• 24:51bladder would look like in
• 24:52in transverse orientation
• 24:54with the indicator towards the
• 24:55patient right. And if we're
• 24:56gonna image it in longitudinal
• 24:58access,
• 25:00longitudinal orientation,
• 25:01the indicator is gonna go
• 25:03to the patient's head. So
• 25:04the indicator, the notch, is
• 25:06gonna point towards the head
• 25:07of the patient.
• 25:09On the screen, it's gonna
• 25:10appear,
• 25:12a little circle on the
• 25:13left side of the screen
• 25:14as you're looking at the
• 25:15screen.
• 25:16And the image itself, you're
• 25:17gonna have
• 25:19ladder
• 25:20and then fully balloon calculator
• 25:22right there. So, that's just
• 25:24the convention,
• 25:25and that's how you're gonna
• 25:26keep this little mark,
• 25:29on the screen.
• 25:31Just general sense of awareness
• 25:32so that, you know, that,
• 25:33if things are converted, you're
• 25:35it's likely that your flow
• 25:36is
• 25:37turned
• 25:38a hundred eighty degrees by
• 25:39accident.
• 25:41Now in terms of positioning,
• 25:42this is a pretty easy
• 25:43concept to
• 25:45understand.
• 25:46Structures that are
• 25:47closer to the probe are
• 25:49gonna appear higher on the
• 25:51screen.
• 25:52So in in this case,
• 25:54we have liver
• 25:56here in front of kidney,
• 25:57and here's your liver,
• 25:59this view. And that's, closer
• 26:01to the top of the
• 26:02screen, whereas you have a
• 26:03kidney that's more posterior,
• 26:05and the kidney
• 26:07is
• 26:08here.
• 26:13If you can read that
• 26:14handwriting.
• 26:15So,
• 26:16position on the monitor has
• 26:17to do with how close
• 26:18an object is to the
• 26:20probe, top of the screen,
• 26:21closer to the probe.
• 26:24Alright. So the gain is
• 26:26going to be an important,
• 26:28function that you're gonna familiarize
• 26:30yourself with so you can
• 26:32become comfortable with how to
• 26:34adjust it when you're doing
• 26:35scans and how to interpret
• 26:36images. So think about gain
• 26:38as the volume
• 26:39of,
• 26:42of your ultrasound,
• 26:44I guess, globally. So if
• 26:45the gain if the volume
• 26:46is turned up too high,
• 26:48everything is gonna appear very
• 26:50bright on the screen. Whereas
• 26:52if the gain is too
• 26:53low, if the volume is
• 26:54turned down, everything is gonna
• 26:56appear too dark. And this
• 26:58is gonna affect your image
• 27:00quality, and it's gonna affect
• 27:02your ability to interpret images.
• 27:03So,
• 27:04on the first one, the
• 27:06game's a little high in
• 27:07that clip there with the,
• 27:10kidney over here,
• 27:12and this actually looks like
• 27:14spleen over here. And this
• 27:17entire area here is is
• 27:19fairly bright. So
• 27:21in terms of assessing for
• 27:22fluid collecting in that space
• 27:24and sometimes we look for
• 27:25or not sometimes, we we
• 27:27wanna look for fluoro fusions
• 27:28when we do these FAST
• 27:29exams.
• 27:30You you're gonna wanna have,
• 27:33just a slight adjustment of
• 27:34the gain here just to
• 27:35avoid all this bright artifacts
• 27:37down here.
• 27:39Conversely,
• 27:40we have a,
• 27:42a child here, a patient
• 27:43with concern for, like, the
• 27:46hip diffusion, fluid collection. And
• 27:48if you're just looking at
• 27:49this area here, it looks
• 27:50kinda dark, and that's where
• 27:51we would teach to look
• 27:53for fluid,
• 27:54to collect.
• 27:55But this is actually an
• 27:56operator error, not even operator
• 27:58error, machine error, however you
• 27:59wanna call it, false error,
• 28:01it would be a false
• 28:02positive.
• 28:04This this is a case
• 28:05where the gain is just
• 28:06too low. You have to
• 28:07increase the gain to be
• 28:08able to distinguish the the
• 28:10the tissue here is actually
• 28:11normal appearing relative to the
• 28:14the hip flexion muscle over
• 28:15here. This is the
• 28:17hip bone over here.
• 28:19So,
• 28:20this is,
• 28:21learning for another day, but
• 28:23gain too high is not
• 28:24helpful and gain too low
• 28:26also,
• 28:27is a potential problem.
• 28:29Yep. Depth also is another
• 28:31big one. So here's a
• 28:33patient with
• 28:35erylocolic intussusception,
• 28:37on the,
• 28:39the first image with a
• 28:40linear with a linear probe.
• 28:42You have a depth set
• 28:43at nine centimeters. So how
• 28:45do I know it's nine
• 28:45centimeters? Well, every hash mark
• 28:47is a centimeter. So one,
• 28:49two three
• 28:51four
• 28:51five six, and it comes
• 28:53down here to to nine.
• 28:55So you have a very
• 28:56end instinct structure there. It
• 28:57just looks like there's something
• 28:59wrong, and it's really hard
• 29:00to make a a judgment
• 29:02call
• 29:03as to what that could
• 29:04be.
• 29:06When the depth is adjusted
• 29:08here to four centimeters, you
• 29:09have a much more crisp
• 29:11appearing
• 29:12target sign where this is
• 29:14ilium
• 29:15here,
• 29:15and this is the outer
• 29:16wall of the ceta
• 29:18here. There's your target,
• 29:21more than two and a
• 29:22half centimeters
• 29:23in terms of, a tube
• 29:24diameter. So this is iliopollicant
• 29:26dissection,
• 29:28which could easily be missed
• 29:29if you're looking at an,
• 29:33at not the appropriate depth
• 29:35setting.
• 29:37Alright. And color doppler is
• 29:39a really important function that
• 29:41we're gonna use all the
• 29:42time,
• 29:44when we're doing scans. So,
• 29:46essentially,
• 29:47you have
• 29:50a application where the ultrasound
• 29:52can detect flow.
• 29:56So the the
• 29:58the important thing to remember
• 30:00is that here in in
• 30:01this first,
• 30:02image,
• 30:04right here,
• 30:06we have a pulsating vessel.
• 30:08Right? So
• 30:09the reason it appears blue
• 30:11is because the appearance of
• 30:12blue in ultrasound is flow
• 30:14away from the transducer. Whereas
• 30:16flow
• 30:17to the transducer is gonna
• 30:19appear as red. So even
• 30:20this is an arterial structure,
• 30:22it's a, vagal artery in
• 30:24this case,
• 30:26The the appearance of the,
• 30:31filling
• 30:32of that lumen
• 30:33is blue because the probe
• 30:35is slightly twisted away. So
• 30:38if I have, a vessel
• 30:40here
• 30:41and I'm looking at it
• 30:43with my probe this way,
• 30:46if I'm tilted that way,
• 30:47you may have a blue
• 30:48appearance. Whereas if I'm twisting
• 30:51this way
• 30:53and,
• 30:54the artery is coming from
• 30:55where my wrist, the placenta
• 30:56that's coming from my wrist
• 30:57is, then it's gonna appear
• 30:59red.
• 31:01Blue,
• 31:04red,
• 31:05but it's essentially the same
• 31:06vessel.
• 31:08And,
• 31:09so, so that's an important
• 31:10concept to
• 31:12be aware of.
• 31:13And,
• 31:14we also use color Doppler
• 31:16flow for inflammation. So,
• 31:18hyperlamia
• 31:19is a common finding,
• 31:21when there's inflammatory
• 31:23to tissues and pathology.
• 31:25This is a an example
• 31:26of hyperremia around,
• 31:29a somewhat ill defined appendix
• 31:31actually on this one clip
• 31:32here.
• 31:34But this is the partial
• 31:35wall of an appendix that,
• 31:37was in a patient with
• 31:38acute appendicitis.
• 31:39So detection of inflammation,
• 31:42and then also detect detection
• 31:44of flow
• 31:45to
• 31:47or away from that transfusion.
• 31:51Okay. We're gonna do some
• 31:52quick hits to finish off
• 31:54here for shadowing. So we
• 31:55have,
• 31:57acoustic shadowing, which is an
• 31:59artifact,
• 32:00that's caused by
• 32:02failure of a sound beam
• 32:03to pass through a certain
• 32:04tissue. So in still clip
• 32:06number one,
• 32:08we have acoustics
• 32:09shadowing because there's gallstones in
• 32:12the gallbladder.
• 32:13So you have ultrasound coming
• 32:14here, political structure, gallstones there,
• 32:17and then this
• 32:20dark defect behind the gallstone
• 32:22here is, an acoustic shadowing
• 32:24phenomenon.
• 32:26Not to be concerned with
• 32:28not to be confused, sorry,
• 32:29with edge artifact,
• 32:31which you're seeing right next
• 32:32to the bellow data there.
• 32:35And, probably a little slightly
• 32:36better, more clear example,
• 32:38would be a heel foreign
• 32:40body. So
• 32:41you have a splinter here
• 32:42that's a little bit bright,
• 32:44and then you give off
• 32:45this complete shadow artifact. So
• 32:47that's,
• 32:48acoustic shadowing, which is an
• 32:49important,
• 32:51oops, an artifact,
• 32:53that we use to interpret
• 32:54our images.
• 32:56The next important artifact,
• 32:58to talk about is mirror
• 32:59imaging artifact, which is a
• 33:01normal,
• 33:03finding,
• 33:04most of the time.
• 33:05So,
• 33:07this artifact is created when
• 33:09you have a
• 33:10curved
• 33:12structure, which is a stronger
• 33:15reflector of ultrasound relative to
• 33:16the object that's informative. So
• 33:18on the FAST exam,
• 33:20you have typically spleen or
• 33:21liver here.
• 33:23Your stronger reflector
• 33:25curved object is the diaphragm
• 33:29there. And given the difference
• 33:31in the
• 33:33tissue interface,
• 33:34you have the appearance
• 33:36of liver,
• 33:38a man's own artifact.
• 33:39But it's really just a
• 33:40mirror imaging artifact that's created,
• 33:43which is useful to know
• 33:44because if you have a
• 33:45pleural effusion or hemothorax,
• 33:48this is all gonna look
• 33:50dark over here. So instead
• 33:52of the mirror imaging,
• 33:54what you're likely to see
• 33:56is
• 33:57a complete,
• 33:59anechoic hypochial fluid collection there,
• 34:02in in in a portion
• 34:04of the plant. So,
• 34:08near imaging artifact.
• 34:09And another example
• 34:11potentially
• 34:12would be,
• 34:13say a scalp hematoma. So,
• 34:16here we have bone.
• 34:19It's a strong reflector.
• 34:21It's curved because it's the
• 34:23skull. It's the scalp.
• 34:25And this is your scalp
• 34:26hematoma
• 34:28hematoma.
• 34:29So that's just, those,
• 34:32injuries that we see with
• 34:33kids all the time. So
• 34:35this appearance here
• 34:37is not an epidural or
• 34:39a subdural or a subcranial
• 34:40intracranial bleed, but it's rather
• 34:43a reflection
• 34:44of the synchrotum behind the
• 34:45bone, near imaging artifact,
• 34:48that you will need to
• 34:49recognize
• 34:51when you're doing the scans.
• 34:53Here we have posterior
• 34:55acoustic enhancement, which is a
• 34:57bright or hypoelectronic
• 34:58appearance.
• 34:59At the posterior or far
• 35:01side of a cystic fluid
• 35:02fluid structure due to the
• 35:03lack of attenuation of ultrasound
• 35:05beam,
• 35:07So you have a bladder
• 35:08here, and the posterior wall
• 35:10appears very bright
• 35:12due to posterior acoustic enhancement.
• 35:14It's not any different consistency,
• 35:18in terms of the wall
• 35:19there relative to the lateral
• 35:21side
• 35:22or the anterior side. But
• 35:23it just looks so much
• 35:24brighter because of the ultrasound
• 35:26transmission
• 35:27through that
• 35:28through the filth bladder. And
• 35:29it's important, again, because of
• 35:32the possibility
• 35:33for, mispathology.
• 35:35So if you're doing a
• 35:36FAST exam and everything looks
• 35:39very, very bright behind the
• 35:40bladder, you may miss
• 35:43free fluid. You
• 35:45may miss free fluid behind
• 35:47the bladder, so just be
• 35:48cognizant
• 35:49of this artifact and adjust
• 35:51your gain accordingly.
• 35:54Okay. And two more quick
• 35:55ones. So reverberation artifact, very
• 35:57important when we're scanning the
• 35:59lung, very important when we're
• 36:00looking at peripheral bodies.
• 36:02These are equidistant horizontal lines
• 36:04that tend to decrease in
• 36:05intensity on the monitor.
• 36:07It has to do with,
• 36:09reflection
• 36:10or reverberation of echoes to
• 36:12and,
• 36:14from the the probe. So
• 36:16in this case, we have
• 36:17the probe
• 36:18here,
• 36:20and we're looking at oh,
• 36:22this lung tissue. This is
• 36:23the pleura.
• 36:24So this is an a
• 36:25line here,
• 36:27and this is a a
• 36:28line
• 36:29here.
• 36:32And you can see the
• 36:32distance between this
• 36:36and this is the same,
• 36:39which is also,
• 36:40similar to the distance between
• 36:41the exact actually, precisely the
• 36:43distance from the probe to
• 36:44when the ultrasound beam hits
• 36:46the probe.
• 36:47So normal filled air, a
• 36:50lines are good, a okay.
• 36:52This is the type of,
• 36:53reverberation artifact that we
• 36:56assume
• 36:57or that we should be
• 36:59seeing when there is healthy
• 37:00lung tissue without any problems
• 37:02you're feeling.
• 37:04Okay. And here's another example
• 37:06of reverberation
• 37:07artifact,
• 37:08sometimes called ring down artifact
• 37:10or comet tail artifact.
• 37:12And,
• 37:12this has to do with,
• 37:15essentially,
• 37:17the interface of the
• 37:19the object where the sun
• 37:21beams are stuck reverberating back
• 37:23and forth,
• 37:24which creates
• 37:26a a deep dive,
• 37:28vertically
• 37:28on on the screen.
• 37:31So here is,
• 37:32an IJ in terms of
• 37:33jugular vein, and then you
• 37:35have a,
• 37:36presumably,
• 37:38a needle here that's coming
• 37:39towards the the lumen of
• 37:41that vein.
• 37:42So the the needle itself
• 37:44has,
• 37:46two metallic portions. Right? It
• 37:47has the anterior portion and
• 37:49the posterior portion.
• 37:50So what ends up happening
• 37:51is that ultrasound beam gets
• 37:53trapped between the two parts
• 37:55of that needle, metallic,
• 37:57tip. And it's gonna create
• 37:59these sort of repented,
• 38:02vertical
• 38:03reverberation
• 38:04dips. So it's gonna pass
• 38:06this to a little bit
• 38:08into the bottom of this
• 38:09one. So unlike unlike just
• 38:11the the a lines that
• 38:12are separated,
• 38:14by the distance of the
• 38:15probe to the cora,
• 38:16this is more of a,
• 38:18persistent
• 38:19ping pong effect within the
• 38:21lumen of that
• 38:23needle,
• 38:24causing a a a vertical
• 38:26dive,
• 38:27and and you would expect
• 38:29to see a
• 38:31a wind down appearance on
• 38:32the screen.
• 38:35Alright. So we've made it
• 38:36to the end,
• 38:38and I thank you for
• 38:39sticking,
• 38:41through,
• 38:42the the lecture.
• 38:44The recap, how how are
• 38:45you gonna get good interviews?
• 38:46A lot of it is
• 38:47gonna be practice, practice, practice,
• 38:49and more practice.
• 38:52But you're gonna,
• 38:53employ
• 38:54some of the, important concepts
• 38:56and and understanding of physics
• 38:58that,
• 38:59we've gone through in some
• 39:00of these slides. You're gonna
• 39:02pick a good probe
• 39:03because,
• 39:04choosing the right probe is
• 39:05sometimes half the battle for
• 39:07for
• 39:08the application that you're you're
• 39:09trying to achieve.
• 39:12Use good windows. Use fluid
• 39:14filled structures to see objects
• 39:15that are behind them.
• 39:17Identify landmarks. A lot of
• 39:19what we do is pattern
• 39:20recognition. So if you don't
• 39:21start with good landmark identification,
• 39:24you're sort of going on
• 39:25a fishing expedition to some
• 39:27extent.
• 39:29Adjust the depth. We don't
• 39:30want any wasted space on
• 39:31the screen, so we want
• 39:33to
• 39:34maximize your
• 39:35object of interest and make
• 39:37it, as big as possible,
• 39:40without losing any of the
• 39:42important detail behind it.
• 39:45Get to know your machine
• 39:46with different,
• 39:48settings,
• 39:49even within a single hospital
• 39:51are gonna,
• 39:52have, different machines with different
• 39:54knobs.
• 39:55And so part of being
• 39:56able to be a good
• 39:57zonologist
• 39:59or a good clinician who
• 40:00would employ protecate ultrasound
• 40:02to help care for your
• 40:03patients is,
• 40:05getting really comfortable and not
• 40:07having to sort of fiddle
• 40:08with the machine if you're
• 40:09there in vivo,
• 40:13caring for for kids and
• 40:14and their families.
• 40:15And and and that's it.
• 40:19Your friendly PEM focus team
• 40:21consists of myself,
• 40:23Emily Chen,
• 40:24and Julie Levener, and we'll
• 40:26be doing the scanning shift
• 40:27sessions together.
• 40:29And we're excited for this
• 40:30opportunity,
• 40:31to augment your experience.
• 40:33We do realize this is
• 40:34an optional commitment,
• 40:36on your behalf. So with
• 40:38that in mind,
• 40:39we're going to
• 40:41provide
• 40:42an extra fruitful experience, we
• 40:44hope,
• 40:46when we're when we spend,
• 40:48time together on these damageships.
• 40:51So the
• 40:53sign up sheet, will be
• 40:55updated quarterly. And,
• 40:58right now with, COVID, we're
• 40:59only limiting to one, maybe
• 41:01two
• 41:02rotators,
• 41:03today.
• 41:05But, there's no limit. We
• 41:07can do,
• 41:08certainly if you're interested,
• 41:10multiple,
• 41:10scanning shifts with us throughout
• 41:12the academic year.
• 41:14And so see you soon,
• 41:16and thanks for listening.