0:05 for the next 30 minutes uh we just see some of the basic aspects of ios imaging started with the imaging system then few words about how this is images are produced and the important part interpretation of ios images and end up with some artifacts i have not covered anything related to ios guidance for interventions i thought maybe that can be a big topic by itself so just to stop with image interpretation maybe if you have time next webinar we just discuss how to use hybris imaging for simple and complex lesions so to start uh some basics coronary angiography use
0:52 extensively in practice and it helps in visualizing the entire coronary anatomy with a single contrast injection culture identifying disease they help some decision making between surgery and medical treatment and pci and as we all know this is a pathway to intervention then why do you need an intravascular imaging once you get all the information from coronary angiography itself however the coronary angiography is it's a luminogram it provides only a two-dimensional image does not provide any information on the vessel wall such as clock distribution and extent vessel remodeling
1:40 and the block composition in addition it is limited by foreshortening overlap and angle dependency so this limits its capacity to quantify the stenosis sizing the reference vessels for strengthening and it is again limited in correctly estimating the scent expansion and opposition more importantly it is less sensitive for deducting post pc complication that's why even though coronary angiography still remains a primary modality for decision making and guiding our intervention we need an additional mortality to understand better what is happening inside the vessel wall and inside the stent
2:27 so start with some important things about imaging systems the imaging system has three parts one is the console console is the source of electrical energy for the transducer in addition it also serves as a display monitor and also a storage device so three functions provides electrical energy display and storage then the second thing is your motor drive unit motor drive unit is responsible for the revolution of your ios catheters so rotation of the ios catheters and there's a pullback device this pulls back i was captured at a constant speed to produce a longitudinal images and length estimation the third party
3:15 showed i was calculator catheter has a small transducer mounted adjective and which is responsible for your image protection and how does this ultrasound system works the basic principle is not different from any ultrasound imaging morality such as echocardiography the console provides electrical energy which is delivered to the imaging catheter and the piezoelectric crystals so this electrical energy is delivered through the catheter uh to the transducer transducer has piezoelectric crystals with this electrical stimulation the special electric crystals produce
4:00 ultrasound bays which get reflected from the tissue interfaces and part of it is collected by the transducer and again it estimates the piezoelectric crystals converted back into the electrical signals these electrical signals are received by the ios console which decodes into the tomographic cross-sectional images the two type of ios systems one is a mechanical which has a single transducer element which goes around the circumference of the vessel to produce a 360 degree images and the second one is based array system which has an array of 64 elements mounted on the tip of the catheter each one gets activated
4:45 serially rather than it is rotating here the 64 elements they get activated in series to predict sequentially to produce the 360 degree image so this is how the ios images are produced under some more information about interaction of ultrasound waves with tissues so before going into this thing we have to understand two terminologies one is the tissue interface tissue interface is the border between two media where there is a change in change in acoustic impedance so the second thing is what is acoustic impedance that is the resistance the passage of
5:32 sound in the medium so that is your acoustic impedance the interface is the border between two media there is a change in the acoustic impedance so when this ultrasound wave interact with the tissue so what happens further that is decided by three important features one is what is angle of incidence of this ultrasound wave with the tissue interface whether it is perpendicular or less than perpendicular the second thing is smoothness of the surface whether this interacting surface is smoother and regular or an irregular surface and the third thing is what is the difference in the acoustic impedance between these
6:18 two media these are the three important determinants of ultrasound wave interaction with the tissue interfaces so here we see an example here this ultrasound signal which is a perpendicular to the surface which is smooth and regular so this results in all the reflected base going back in the same direction to the transducer so smooth regular surface and perpendicular interaction the reflective is go back goes back to the transducer so almost all the ways back to the transducer okay so what happens further so further transmission of the wave into the next interface is determined by the
7:04 acoustic impedance difference between the two media if this impedance difference is very large most of the ultrasound waves are getting reflected from the first interface itself and the less amount passes to the next interface if the difference is small and the most of the ultrasound base are allowed to pass through the next interface again the same thing happens in the next interface and again the same properties the difference between the impedance goes to the third interface and get reflected so this is on the regular surface suppose if the surface is not regular but still the angle of incidence is a perpendicular there is something called scattering
7:51 occurs that means the ultrasound bays are reflected in different directions so this is called the scattering only a small amount of scattered reflected wave reaches your transducer and helps in formation of your image suppose your angle of incidence is not perpendicular what happens just gets reflected at the same angle so if it is 30 degree of incidence to the vertical line and get reflected at 30 degrees or up to the opposite direction and the sun results in formation of any image so it doesn't participate in the formation of image because it is perfected away from the transition suppose the surface is irregular and it
8:36 gets scattered similarly and part of this wave is reflected back to the transducer performing above the image and what happens in the transmission part if there is a big difference in the speed of sound between these two media this means it refracted that means it just did bend and goes in a different direction usually this refracted days do not participate in the formation of the image sometimes when they get reflected they result in artifacts so this is the basic software interaction of ultrasound tissues and in addition two other things you have to understand what what things what are the two things
9:22 which produces shadowing are it is the overvisibility of the deeper tissue the two things one when the acoustic impedance between these two media are very large as explained early all the ultrasound bays get reflected from the surface itself so nothing goes into the second interface so that causes shadowing where you can see only the leading surface and remaining things are shadowed so this is called this phenomena is called shadowing the second phenomena is called attenuation attenuation is nothing but decrease in the strength of the ultrasound base when it travels into deeper into the
10:07 tissue due to mainly absorption or reflection in different directions or scattering so these are the three things reflection in non-perpendicular direction scattering and mainly absorption which converts the kinetic energy to heat energy so that result in over penetration of ultrasound waves into the deeper tissue this phenomena is called attenuation so these are the two phenomena which result in over visibility of the deeper tissue what happens when the ultrasound reacts with the tissue or we react with the structure which is smaller than its wavelength that again results in scattering of the ultrasound base so this results
10:53 in speckling most common example is rbcs if you have a slow moving rbc that results in speckling inside the lumen so this phenomenon is called scattering okay so now we have seen shadowing attenuation scattering and reflection and back scatter and moving forward how does image is formed so image for forming an image you require two information one is where exactly is the particular structure is positioned in the tissue architecture and second information is what is the brightness how much is the reflectivity of the that structure here you can just see that the first interface it is the depth information is given by
11:41 the time taken for this ultrasound signal go to the interface and get reflected and come back to the transducer this travel time gives you information of death we all know the science velocity of the sound is 1540 meters per second and this is multiplied by this travel time you get the the depth means the length it has traveled that gives you the depth information here its shortest dispersed interface shortest distance into travel then it is much more than first interface and this wave traveled much more than so this will reach us early and it is delayed and it is further delayed here so this will provide the depth
12:27 information then second thing is what is the intensity what is the strength of the reflection higher the strength the structure appears brighter and lower the signal strength the structure appears darker so that they call as reflectivity better reflectivity brighter structure and poor reflectivity the darker structure okay and this is how this information is translated to images here you can just see this is the depth information it is the derivative from the pathway travel time so flight the time of flight so after ultrasound days here you can just see that this this point this wave has traveled for long distance intermediate distance and short distance in addition we also provide the intensity that is
13:15 the intensity of the reflection this is a brightly reflecting tissue overly reflecting tissue and again brightly reflecting tissue each one in different depths and each one has a different intensity this forms one a line so we all know it is a ultrasound image is the it is the amalgamation of multiple a lines so this is first aiding and the ultrasound catheter image the next part next airline and this is the third airline so this is how the images are produced here you can just see that how it happens it forms multiple airlines the character moves around produces airlines here and this is a deeper structure intermediate structure superficial structure it is bright
14:01 structure dark structure the second bright structure good reflectivity over reflected so this is how ultrasound images are formed in intravascular centre soft and some of the basics about ultrasound image the ultrasound images are analogous to histological sections they produce images not it is similar to astrology not as as high resolution images as histology just one micron resolution and i have a cells about 150 to 200 micron resolution for the images tomographic images are similar to histological sections and these images are oriented from the eye stream of the coronary artery if you take example of echocardiography are computed tomography all the images are
14:47 oriented from the food end of the patient here the intraocular ultrasound images are oriented as if you're sitting inside the sinus of valsalva and viewing into the costume of the coronary artery and there is no absolute anterior posterior right and left orientation to the images they describe the images as if viewing the face of the clock we just explain some of abnormality at trending from two o'clock to five o'clock position or something extending from seven to ten o'clock question that is how you describe the abnormalities in ios images and we use five branches and perivascular landmarks such as pericardium muscle tissue and the venous system to orient ourselves inside the coronary artery so this is
15:34 how we orient ourselves and we see some of the so how does this normal coronary artery of psr intravascular ultrasound imaging we all know coronary artery has a lumen and a three layered vessel wall architecture this human appears echo losing with the bread speckles you can just see that small white white spots of lipstick otherwise it is mostly a collusion it has the catheter in the middle if you have a solid state system the guideway runs through the center of the catheter you don't see any kite catheter artifact suppose if you are using a mechanical system the guidewire runs outside the catheter if you remember the first image you showed so you see via artifact in that image and then
16:21 comes the three layered vessel wall architecture the inner layer is endema which is rich in collagen and elastin so it reflects sound intensely so this layer appears bright the second layer is media mainly made up of smooth muscles smooth muscles doesn't reflect the sound sorry i just told light it is actually found it doesn't reflect the sound intensely so that results in darker image in advance the third is again it is adventistia rich in collage sheets of collagen from this adventure brightly reflect the sound so again a brighter structure so it forms the brighter inner layer endema darker middle layer that is medium and outer bright layer that is the adventitia so bright dark bright that is the normal
17:08 activities of the vessel wall on i was imaging as we all know atherosclerosis is the disease of india with the development and progression of atherosclerosis block accumulates in the endema and the intimate thickness gradually increases this is the typical appearance of a diseased artery and the coded and echogenicity of this block depends on its constituents whether it is made up of lipid or it's made up of fibrous tissue or it made up of calcium so this is how this block develops so this is a typical example of a glucose you can just see that the plot material develops and gradually narrowing and everything is located in the indiana space and the plot can accumulate
17:55 concentrically that means it goes around the circumference of the vessel or it can be eccentrically it occupies only part of the circumference here this is an example of concentric block and here this is an example of a eccentric block we need to understand some of the terminologies before going to image interpretation the first terminology is blood spectral i already have shown some examples so here you can just see blood sprinkles are nothing but finely textured echoes moving in swirling pattern the two type of blood speckles can you see here this is an led artery the bristles are much darker that means blood is flowing faster so the ultrasound has less time to interact with the red speckles and the blood rbcs are distributed
18:42 sparsely and here you can just see another example this is an occluded diagonal branch after led stenting the speckles are bright that means blood is not moving and it is still there is the stasis of blood inside the vessel so that results in more rbc's in the same space and more time for an ultrasound to interact with it so that produces brighter speckles when you have a high resolution imaging catheter that means it is a particular sixty mahaprabhu the blood speckles usually are achieved usually appear much brighter comparing to artery the veins have much brighter speckles because the blood moves much slower in veins okay this is an example of dark gray speckle that means a
19:27 fast moving blood and this is an example of right speckle that means it is stagnant uh blood so are slow moving blood the second terminology is pericardium here you can see that stripe of tissue which moves a true and fro with systole and you should see i spoke like reverberations dark stripe of tissue scope like reverations and back and forth movement with cardiac cycle is your ricardium and the echoes free space that appears uniformly done is pericardial space the pericardial space is an echo spree space around the coronary artery so this is a typical example of pericardium
20:12 and this is a typical example of a pericardial space and what is the venous structure here you can just see that this structure here from one o'clock to four o'clock at five o'clock position and just so this is an oval structure which exhibits a solid compression which runs either parallel r perpendicular to the artery and doesn't join it so that is the typical definition of the vein on ios image and again the blood speckles will be brighter because the blood moves slower in the vein and how do you differentiate it from higher brain cybrans is the one which joins the main vessel here you can this is a typical example of a side branch okay
21:00 next one and now we see some of the examples of different arteries first we'll start with lip main coronary artery you see the least main coronary artery it originates from the electrolytic sinus and the runs through the transverse sinus behind the pulmonary artery and coming on the left side between your uh in the atrioventricular group i i under devised into lad and lcx so what are the various relations if you public iota so part of the austrian cure and this is your iota that marks your left brain osteum osteen has oblique iota in its view then you move
21:46 to the soft of the left main coronary artery it travels through the transverse sinus transverse sinus is nothing but a pericardial space that is formed by reflection of pericardium from the great arteries to the surface of the heart so this is your typical transverse sinus transfer sinus marks the middle part or soft or the left coronary artery the distal part is marked by bifurcation into lab and lcx another pericardial space that i'll show you later so ostium it is iota and middle part relation is transverse sinus and the distal part is the bifurcation so what are the various relations of the left anterior descending artery
22:31 we all know left anterior descending artery runs in the anterior intraventricular group and is related anteriorly to the pericardium posteriorly to the myocardium on the left side to lcx and diagonal branches and the major anterior intraventricular vein which is again on the left side and the central branches comes on the myocardial side because it perforate and directly goes into the receptor muscle and the diagonal male 6 which comes on the left side so these are the various relations of the flipped anterior descending artery and here you just take it here this is the osteol part of the left anterior descending
23:17 artery here this osteol and proximal part of the led along with the proximal part of your lcx and the reflection of a great cardiac vein from the anterior interventricular group into the left atria of anticlockwise triangular the pericardial space this pericardial space is called triangle of broken motion dynamics food defined who identified or defined this pericardial space that is called by their name so this triangle defines your osteo part of the led here you can just see that lcf and lad and this is the pericardial space this is called triangle of broken motion and this is a constant landmark that cost him of the led and what happens to the mid and
24:04 distal part of the led the distal part of the led is usually accompanied by two venus the two venous structures so here you can just see that produces an old eye appearance here this is your artery with your eyebrows catheter and this is one of the anti-inflammatory chlorines and another and anterior intraventricular vein which is on the right side this is on the left side and it is covered anteriorly by pericardium bright type of tissue with spoke like a reverberation artifacts and here you can just see that echolution to myocardium so this is myocardium this is pericardium this is the right anterior interventricular and left side of anterior intervention chloride and this is your medium distal part of the led and your septal branch comes on the
24:50 myocardial side the diagonal branch comes on the left side and your l6 again comes on the left side so these are the various relations of left anterior descending artery and how do you differentiate between diagonals and septal see these examples here this diagonal branches usually run along with led for a distance and so when you see with iowa there's the diagonal branch often seen in the far field you see the branch in the far field and gradually moves towards led on your full back and this diagonal branch is located about 90 degree of angle to the pericardium if you see pericardium will be on the anterior surface it comes on the left side from the side
25:37 so it is 90 degrees from the pericardium and it is about 90 to 180 degrees from the left septum septal branches because this diagonal branches come from the surface when you move very distally where the artery moves deeply into the myocardium so it is separated 90 degrees once it is on the side and it comes from the anterior surface it is about 180 degrees separated from the septal branches and how do you identify separate branches you all know the sepal branches they just originate and go perpendicularly into the myocardium so the branch which has a wider angle from the led which is more perpendicular and appears to just cut away from the led abruptly you can just see that just pulled away from the led rather than
26:23 seeing from the far field and comes in joints and these comes on the myocardial side so this is how you differentiate between diagonals and the central branches on ios imaging and what are the relationship of lcx here you just see that the uh and do both intraventricular veins join to form a single intraventricular vein which is on the left side which becomes a great cardiac vein and gets reflected into the left atrioventricular group this great cardiac pain lies on the atrial side of your lcx so this is how it just hugs around your lcs there is a great cardiac vein a branch which comes towards the great cardiac vein is your atrial branch the branch which goes away from your great cardiac frame is your
27:09 marginal branch this is an example of marginal branch great cardiac point which comes in the opposite direction so these are the various relationship of your lcx now what happens in rca you have we have seen that in lad and lcx the venus structures move along move parallel to the artery here the venous structures move perpendicular to the rt that produces harsh shoe shaped appearance of venous structure in rca the marginal branches just goes along with this venous structure so this is a horseshoe shaped appearance it just goes perpendicular to the main article because along the marginal branch so this is what given you getting uh when you image rca with ios
27:56 so what are the basic characteristics you use for ios grayscale ios characterization we use five parameters one is echogenicity echogenicity in which the adventitial echogenicity sounds as your reference just to say whether it is more equal or less echogenic comparing to adventitia second one is shadowing shadowing we have already explained it is complete reflection of the sound waves from the surface so that results in poor visibility of deeper structure that is called shadowing attenuation is again we have explained previously that the reduction in the intensity of the sound base has a pass through the tissue due to absorption scattering and reflection that is uh what is the penetration depth the fourth one is reverberation
28:43 that we are going to explain it later so the reverberations are nothing but ghost images from repetitive reflections of ultrasound base then fifth characteristics is intimate thickness less than 300 is normal thickness 300 to 600 is a physiological intimate thickening that is the thickening which happens due to physiological response to stress and more hundred six hundred microns indicates that logical interval thickening are fibrous so these are the five features one is echogenicity second one is shadowing third one is attenuation fourth one is reverberation the one is intimate thickening so now we start our image interpretation you see a flock here what is echogenicity so this is your argentia and this is
29:29 your block both have similar echogenicity that is your fibrous block so isoechoic is fibrous block you see the tissue here see what is echogenicity here it is hyperechoic comparing to authenticia what addition you see you are seeing only the leading edge of the clock and the first shadowing the third thing you can just see that goes some ghost artifacts here so these are all called reverberation that is resulting from repeated reflections if you see these three features one is it is plot which is hyperechoic adventitia dorsal shadowing and reverberation that is your fibrocastic block your block here you just see in
30:16 contrast to these things it is isoechoic and this is hyperechoic which is hypoechoic comparing to adventistia that is called the soft block most probably is contained more often liquid material the two special type of soft blocks first one is attenuated block attenuated block means a iso-echoic block this is an iso the deep signal loss so iso eco block with the deep signal attenuation is your attenuated block this attenuated then second special type of cloth is a collusion block here you can just see a block with interrupt block equilucency this is called echolocentric block and these two three plots are very
31:01 important these are very important determinant of slow flow or no flow and peripheral myocardial infarction during pca and the plots we commonly see are mixed at once where none of the components make up more than 85 percent of the clock material so this is what we see is plume except you see that calcium soft elements and fibrous elements typical example of a mixture plot and what you see here is a black typical example of plaque rupture so what is plaque rupture ah block rupture is nothing but intra plot cavity with the communication to the lumen so this is your lumen and this is your block and this is your
31:46 cavity inside the plot and this is where fibrous gap remanence and you can just see the small thrombus is sitting inside so this is a typical appearance of the rupture clock under resulting acs and the next one you see here here you can see a structure which is an intra aluminum freely mobile mask with clear separation from the indian layer so this is your typical ios appearance of thrombus so this completes the basic interpretation of different morphologies so based on the echogenicity of adventitia as a reference isoechoic fibrous tissue hyperechoic with shadowing and reverberation is fibrocastic tissue hypoechoic is soft block isoechoic block
32:32 with deep singular attenuation is attenuated block and the block with interrupt block equations is a collusion plot a block with more than one characteristics is mixed block a block with intra plot cavity with communication to your lumen is a block rupture a freely mobile intra-luminal mass with clear separation from the advent with the intimal layer is the thrombus okay this is the most important slide what we are going to show today and something more about attenuated clock what is the importance of activated block i already explained when you have signal attenuation in the deeper part so here these two are examples of deeper signal attenuation yes usually have lipid or early necrosis
33:19 if that innovation is superficial they have advanced necrotic block or thin cap fibroid aroma so these are the ones think fibrotherma and the big necrotic core these are the one resulting in nori flow so deeper ones is either pathological individual thickening that is the earliest atherosclerotic abnormalities or early fibrous either lipid or early necrotic flow superficial attenuation is late necrotic core with advanced to fibroid aroma and very superficial ones with a thin layer is then fibrous roma however iverson doesn't have a resolution to measure the fibrous cap that is indirectly
34:05 evidenced by uh this attenuation which is closer to the human and how do you classify fibrocal speak clock based on their location it is a different it is classified into superficial which is closer to the lumen this is the superficial calcium which is closer to the lumen and the second one is deeper calcium which is closer to the adventitia so this is a deeper calcium and this is your superficial calcium how do you quantify calcium by measuring the or it encompasses so here this calcium encompasses 200 degrees along the circumference so this is how you classify calcium and two special varieties of
34:51 calcium first one is called calcium spotty calcium so fatty calcium is nothing but a calcium which substance less than 90 degree of the vessel circumference so this one is called for a spotty calcification so this is the histological appearance of this particulation the second one is the protruding calcification otherwise called as a nodular calcification these two even though calcium is considered a sign of stability these two type of calcifications are associated with the clock instability and fibrous cap description and acs so these two one is multi calcification and the calcium nodule and typically
35:38 when it causes acs it is called as eruptive calcified nodu that is that means calcium just erupting through the fibrous capsule into the lumen these two result in acute coronary syndrome and see this example here you can just see the natural ground showing a multiple flap-like appearance we usually call it as a spontaneous coronary dissection but with ios imaging and oct imaging we now know that most of these things are recannalized thrombine so recantly strombe is nothing but thrombus is nothing but an intraluminal mass with the multiple channels you can see that multiple channels specifically called as lotus root or swiss cheese appearance this is the longitudinal view showing
36:25 multiple channels so this is the typical appearance of recanalyzed thrombus and some of the specific morphologies that are specific to chronic total occlusion in chronic total occlusion the lumen is occluded or lumen is filled with the intimal plot so there is no lumen at all it is occluded with the indian block so when you say that you have passed your wire from true to true you are actually going through the indian block how does it appear this is this blue part is your intimate block and this is your white part is your media and this is your adventitia so when you are saying that you are going through true to true you are actually going through the intimal block how does
37:10 it appear on ios here you can just see that three layer restaurant architecture the whole thing is intimate block your wire is going to the center and this is your ios catheter so this is the typical appearance of a true to true or individual tracking on ios secondly you are not going through india plot the second space you go through is that is a common thing we do every day is the sub intimal space subminimal space is nothing but passage of wire in the medial space the one peculiarity of medial spaces it just expands easily by your wire movement it just expands circumferentially and longitudinally by your wire movement
37:57 so this is a topical of the appearance of a wire in the subminimal space this is a wire with your eyewas cathedral this crescent shaped structure is your hematoma and this round structure use your collapsed indian plot you've gone through here and this space accumulated a lot of blood and this intimal plus is collapsed to one side so this is a typical ios appearance here and this is your collapsed individual plot and your ios catheter in the subunit space or in the linear space and this crescent shaped structure is your hematoma so this is your hematoma with ios catheter and this is your collapsed individual pill plot so this is the typica of
38:45 passage once you cross and goes into the distal path either you will be in the luminal space that is here or in the sub individual space here this is called as false limit because you have a lumen here there's no occlusion so this is called a false human and this is called true lumen once you enter the false human how does it appear once you enter the false human again the true lumen collapses to form a bean shaped structure how do you differentiate true from false a true woman is a three layered structure here you can see that intima media and adventitia this is a three layer structure that differentiate true women from the false human your ios catheter here is in the
39:31 false human false human is a single linear structure so these are the various morphologies you see during cto intervention and what is the dissection dissection is nothing but bridge in the lumen continuity here you can just see this is your lumen continuity and there is a bridge in it so this is a typical appearance of dissection how do you classify a dissection based on the axial extent it is into endema or into the media or into the adventitia so intimate dissection medial dissection or advantageous dissection based on the circumferential extent so that is quantified by how many degrees along the circumference it occupies you say that 60 degree
40:18 dissection 80 degree 100 degree dissection the longitudinal plane how long it extends about three millimeter five millimeter like that so this is how we quantified and qualify dissections we have to tell we have to specify three informations what is actual extent what is the circumferential extent on what is the longitudinal extent and what is intramural hematoma intramural hematoma is the accumulation of blood in the medial space commonly results from balloon dilatation or stenting so it is some continuation of dissection that is the nose where in plane dissection there is space for this hematoma to ex
41:04 to move distally into the vessel so it doesn't accumulate inside when one side it is closed it passes ametroma so what is the typical appearance here you can just see that this is your medial space and this is your lumen you see this carefully follow this media it's split into two this is part of media and this is part of media and accumulation of blood in the medial space it is an intravascular accumulation of blood this all the bright things are rbc's densely packed inside your medial space so this is a typical appearance of the intravascular or intramural hematoma here it is lumen and your blood is still
41:52 in the intravascular space and here this is an example of extravascular hematoma here this is your lumen and this is your vessel architecture there is a breach in the architecture the blood accumulation the peri adventitial space so this is your extravascular hematoma this is intravascular and this is your extravascular hematroma okay what is smaller position smaller position is lack of contact between strength stretch and the vessel wall with movement of rbc's in between you just see that sensors here and this is your intimal surface and movement of our bases so this is the typical appearance of your mala position and you have a
42:39 special function with volcano system so where you can see the doppler movement outside these transistors so this function is called chromaflow it exists only with the solid state system of phillips and what is the tissue prolapse the tissue prolapse is nothing but to prolapse us sorry relapse of the acrylothrombotic material prolapse of the atrothrombotic material into the strength so that is your tissue prolapse it contains either the atherosclerotic material or the thrombus so this is a typical appearance of tissue prolapse you can just see that this is your strength
43:24 and this is all collapsing material between distances this is the case that are done in an svg graph and just see that and geographically how much it is narrow you can see the strength only if the clock flow and all the remaining are prolonged tissue this is a longitudinal view showing the relapsing inside you can just see the extensive relapse of the thrombotic material inside the strength and what is muscle bridge here you can just see that this is the typical angiographical muscle bridge and here you can just see that the muscle layer goes around the artery you can just see from here it goes around the artery the artery exhale systolic using
44:09 motion so this patient was given a lot of ionotropes so this is actually the uh the systolic compression so this is a typical appearance of a muscle bridge and what is coronary arterism we define coronary aneurysm with ivers in the same way as we define with the coronary angiography cylinderism is a part which is more than 1.5 times the diameter of that of reference segment so this is the typical appearance of under the sum cyrus helps in differentiating between true anderson where you see all three layers in fact when there is a bridge in the vessel wall continuity that is when false aneurysm are pseudo under some that can be easily
44:56 identified with the arrivals and what is the remodeling remodeling is the change in the vessel size at the at the lesion site comparing to the reference segments if it is bigger it is called positive remodeling and if it is smaller it is called negative remodeling with this two reference segments this is segment is smaller that is negative remodeling that appears typically in chronic stable angina patients here you just see that this is bigger than the reference this is positive remodeling usually occurs in hcs patients one word about radio frequency i was this grayscale ios uses only the envelope information in the reflected signals and
45:42 it is discriminatory power is limited to improve the tissue discriminative power this newer systems uses radio frequency signals behind this envelope for tissue characterization there are three such algorithms developed by different companies this is algorithm from philips that is called virtual histology which is based on the spectral analysis of the samples that is collected from the cadaveric mark cadavers so based on this it has developed an algorithm that codes tissues with the different colors the second one is imap that is based on pattern recognition of the spectral similarity
46:28 with the reference samples the third this is from boston scientific and the third one is integrated backscatter that is from uh cerumo ivers that uses average power of the backstatin signals among these three only the virtual astrology is extensively validated it color codes different tissues with specific colors dark green fibrous tissue is coated with a dark green fibro fatty tissue is coated with light green necrotic tissue is red and the calcium is white so this improves the discriminatory power of your ivors even though it came in big way we don't use it in routine practice because it doesn't have much of
47:13 value in our routine computation so this completes image interpretation now we move into the last part of the presentation that is image artifacts is very very important to understand this image artifacts to mistake it for normal anatomical or pathological structures the first abnormality is a non-uniform rotational distortion this is unique to mechanical systems so that results from mechanical binding of the drive cable that rotates the transducer that results in circumferential distortion or smearing of the image as you know the transducer has to go around the 360 degree to produce a nail
47:59 the part of the rostration is constrained that produces this onion peel-like appearance that is called non-uniform rotation deformation because it results from the non-uniform rotation of the transducer it is caused by tightening of your chemostatic valve if it is too tight that result in entrance to the rotation of the ayus catheter when used tortures a small guiding catheter using a firefighting character or using a guide catheter with a multiple curves such as amplets or catheters when there is an acute bend in the artery or when there is a type calcific stenosis and the most commonly in our setup it results from defective imaging catheter
48:45 because of the repeated use or thinking of the imaging sheath all these things few are correctable with your techniques and few are not correctable so all this is the results in conifer non-uniform rotational deformation the clinically importance it implies the circumferential resolution you are not able to see what is happening this part of the circumference of the artery and again it makes the measurements unreliable because you can't see where exactly the intimal surface ends so this is clinical importance of non-uniform rotational deep distortion it doesn't occur in paste error system because it doesn't have a rotating element the second one is true and fro artifacts
49:31 when you're doing an ios imaging av crew arteries that is rca and lcx they move vigorously during cardiac cycle that result in movement of the to catheter artery before one circle image is formed so whatever you get in the image is combination of two circles you get these type of image rather than a single circle image that makes your measurements unreliable and the third one is this is one other most important thing you have to recognize that is the kite catheter artifact here you can just see that guide cutter is deeply encased into the artery and you should not mistake this one for a calcified block or the osteon so this is the image when the
50:17 guide catheter is inside and this is the image when the kite gets removed so you should not mistake it for calcium at the auto austrian junction and another thing is ringtone artifact bring down artifact is nothing but bright halos of various thickness surrounding the surface of the catheter so this is a typical bring down appearance it results from acoustic oscillation that is high frequency oscillation closer to the surface of the transducer so what is the clinical importance it creates zone of uncertainty in a bigger vessel it doesn't make a big difference when you are imaging a smaller vessel this ringtone that empires your capacity to identify the
51:03 abnormalities closer to the vessel suppose you take a tighter stenosis which is hugging the ayahuasca you'll be mixing this part of the information so the system produces something called ring down suppression function so that removes this ring but still suppresses the information closer to the catheter so this is the typical appearance of a bring down artifact the blood specular artifact when there is a stasis or when you are using a high frequency catheter the blood speckles appear much brighter so it does it impairs your capacity to identify the lumen andema interspace we want to see this one clearly you have to either inject contrast or saline to remove the red speckles here this is an example of injection of
51:49 saline you can just see identify the interface clearly and the shadowing shadowing occurs when all the ultrasound base reflected from the surface so this is the shadowing which results from calcium calcium intensely reflect the ultrasound signals so that result in shadowing of the deeper structures the other structures which cause shadowing are your air bubbles and stem cells and your guide wires the guide wires are again metal structures the reflector ultrasound based on the surface that causes shadowing so these are the common causes of shadowing in ios imaging air verbal is the biggest enemy of ios
52:35 imaging and air trapping in the sheath and i was critical again it occurs with the mechanical catheter doesn't appear occur with solid state system because there is uh sleeve around the catheter in solid states you can just see that over image quality when you flush with the image quality improves you can cause another abnormalities like that if you use diffuse bright appearance you cannot identify anything this can also produced by presence of air bubbles inside and air bubbles can cause prominent reverberations artifacts also so multiple artifacts can be caused by presence of hair bubbles so you have to clearly flush delicately plus the catheter to remove all the air bubbles to avoid these type of abnormalities and
53:23 reverberation reverberation is nothing but repeated reflections between the catheter and the highly reflective surface suppose you take a metal stencil or a calcium so the impulses get repeatedly reflected between this surface and the transducer so the system counts each reflection as multiple times it is travel [Music] so if it travels two times that means it travels to depth two times a depth so it produces another image exactly twice the distance and again if it reflects three times it forms an other ghost image at the exact three times the distance between these two structures so that is the so what is the clinical importance you should not mistake this one for a
54:08 different interface you should not think that there are three interfaces here it's actually in one interface of calcium that has produced a reverberation of multiple interfaces these are all ghost shadows you should not think that there are multiple interfaces occurs more commonly with calcium when you do protabulation it polishes calcium the reverberation becomes more prominent and this is your guide catheter kite catheter is another one which produces prominent reverberation so this is the guide catheter related reverberation and this one is strength strut related revibration you can just see that multiple various substance here actually there is only one layer this all artifacts and this is your guide wire related reverberation
54:54 and this is your air bubble related evaporation these are the various things which can cause reverberation artifacts in ios imaging and what is siloed artifact usually the main lobe is the one which results in formation which contributes to the formation of the image these side lobes are usually innoceous when they encounter strong reflecting surfaces like strained edges or calcium they too result in contribute to the formation of the image this they follow the circumferential sweep that actually results in extension of strength such or extension of your calcium this produces a false appearance of
55:39 small opposition of sensors this produces false appearance of the dissection closer to the calcite block so you should keep it this side of artifact in mind to misinterpret this as a smaller position and this is nothing but an artifact and lastly what is the stand ghost artifact stain ghosts are reflections from stained metals from the opposite side from the true structures so it should not it make it difficult to distinguish from the truth at the mala position so this is a typical ghost artifact of stencils this is actually a reflection from the opposite side it's not the true structure so you should not mistake this one for center molar position
56:26 this completes the presentation of image interpretation thank you thank you so much doctor i think uh i think one hour is not sufficient for this but i think we need to keep some more session there are some questions which i just wanted to uh take it up to you doctor yeah uh the first question is does tissue prolapse after des uh need restrainting so it depends on amount of tissue prolapse actually there is no definite criteria the luminous human that means the remaining area inside the strength is big enough for the blood to flow you don't have to do anything just leave it alone so the different criteria has been proposed the first criteria was proposed by harrison mi trial that considered
57:13 adequate lumen is four millimeter square we have a flow area less than four millimeter square you have to do additional intervention either you do suction you do prolong the long prolonged low pressure balloon dilatation or if it still remains and occlusive you have to put an additional stenting okay and an additional criteria is defined in illumine three study which consider adequate luminous more than 90 at least 90 percent of the reference human area and practically if you feel that human area is not adequate you have to adequate this thing with the balloon dilatation aspiration or additional strength
57:59 fine that is one more question doctor can we use ios in corroted pottery also yeah we can use dedicated peripheral life catheters are available so we can use similar way for carotid also but the issue is most of the times radials to use our doppler imaging ultrasound the doppler uh probes we made the arteries from externally to characterize the plots rather than using an ios but ios can be very much useful and corrupted art imaging too okay and one more question a ring down artifice is common how to avoid this so you can't avoid it because it is common most commonly occurs with a solid state system the the manufacturer gives a function called the ring down suppression
58:45 so yeah how to do bring down suppression with what you need so that is how you can avoid it okay and how to measure vessel size yeah that is a different topic i didn't touch it because i thought maybe that will do it with the intervention station so you measure you so if you see an uh artery normal non-standard artery i'll just show you an example here yeah take this example here if the artery is non-stented there are two interfaces first one is your lumen endema interface if you measure here what you get is lumen measurement either area or it can measure diameters that is your lumen measurement
59:31 and the second interface is external elastic membrane interface that is where that condition starts then that is how if you measure this area that gives you vessel dimension either vessel area or vessel diameters that is your external elastic membrane area that measurement is made at the junction of the media with adventitia okay how to correctly identify lumen vessel wall interface when there is a significant blood speckles you have to inject contrast or saline to remove the blood speckles then you can i showed an example here so this is your typical blood spectral artifact
1:00:17 let me see so this is what happens when you have a tight stenosis or stasis so you cannot identify the lumen in the interface here this after injection of contrast you can clearly identify the human endema interface how to differentiate between the shadow and side lobe site lobe is an additional image it's not in shadow silo usually it is similar to what you do in regular echocardiographic imaging usually the main beam is a one which forms the image suppose you have a highly reflective surface and the side lobes usually they do not participate in image formation when they get reflected from these edges
1:01:04 they form additional image they also contribute image by extension of this tensor or calcium that appears as along the circumferential sweep that appears understand elongation abstention or elongation of calcium this produces a false appearance of model position this produces a false appearance of the dissection this is actually an image and shadow there is no image shadow occurs when there is a dominant reflection from the surface none of the ultrasound base goes through further where you can see only the leading edge so all these things are shadow so that is the difference between shadow and your side looks i love is actually an image shadow there is no image
1:01:52 and one more question where to use oct and where to use ios uh depends on your a prominent work if you do more of acs work are you more more of a bifurcation and where this is resolution is very important our three-dimensional imaging is important of course it is better than i was and your predominant work is left main intervention uh your cto intervention is better than oct imaging and the post strength assessment and both ios and ocp are equally good how to choose the size of the strength diameter bracket diameter by lumen area vessel area so two ways of selecting your strength if you are using the external elastic
1:02:39 membrane dimension of the reference not the lesion if you are using the external elastic membrane diameter as your reference you have to undersize the strength to the nearest to 0.25 the mean external elastic timer in diameter at the reference is 3.5 millimeter you have to put a 3.25 millimeter or 3 millimeter strength if you are using the lumen reference at the reference lumen reference you have to upsize by 0.25 suppose your new knee lumen diameter is 3.25 millimeter you have to put the three point five strand up size to the nearest point two five in case of human dimension downsize to the nearest point two five
1:03:25 millimeter in case of external elastic membrane paste selection yeah thank you so much for arranging this it is a wonderful experience for me maybe if time permits in near future we may do one on how to use cybers to do uh intervention thank you so much thanks for organizing this thank you so much so there was a fantastic participation of
