 Hello everyone, I am back again with another topic, caesarean scar pregnancy spectrum of cases. Now what is the etiology of CSP that is the caesarean scar pregnancy? Pregnancy in the scar from a caesarean delivery is located outside the uterine cavity and is completely surrounded by myometrium and fibrous tissue of the scar in the prior low uterine segment. Invasion of the conceptus into the myometrium is believed to occur through a microscopic defect or a dehiscence in the scar secondary to poor vascularization of the LUS with fibrosis and incomplete healing. Now there are four diagnostic criteria proposed by Gordon at all which are most widely accepted. One is obviously an empty uterine cavity without contact with the sac. This is a clearly visible empty cervical canal without contact with the sac. Then the presence of the sac in the anterior uterine isthymus or thinning or a defect in the myometrial tissue between the bladder and the sac and most of the cases have myometrial thickness of less than 5 m. So here we can see the sac in the scar, previous scar region, empty uterine cavity and empty cervical canal and there is thinning of the anterior myometrium. TBS is the gold standard for diagnosis, combined use of ultrasound indicators like the relationship between the gestational sac and the caesarean scar, the source of trophoglastic blood flow around the sac, the thickness of the residual myometrium and about the size of the CSP mass. So all these are very important and together improve the differential diagnosis between the CSP and the other pregnancies which are implanted in the lower uterus. Some people advocate the combined endovaginal and transabdominal ultrasonography to obtain a panoramic view of the uterus. Now for Doppler findings also we have to know that there is high velocity and low impedance surrounding the pregnancy of the sac and on pulse Doppler examination with the default settings the flow waveforms of high velocity that is peak velocity more than 20 per centimetres per second and low impedance that is PI less than 1 have been reported. Studies have also shown that in patients of CSP with bleeding they have larger gestational age and lesion size, thinner uterine scar thickness and richer peritrophoglastic perfusion. So here we can see this is a grade 2 CSP, our grading I will be dealing with later on. This is the grade 2 CSP and we can see extensive peritrophoglastic flow and in the GS also. Then this is grade 1 CSP and here also we can see a peritrophoglastic anterior myometrial flow. Risk factors for CSP, obviously multiple prior cesarean deliveries, previous DNC, previous abnormal placentation, previous uterine surgeries like myomectomy, metroplasty, histroscopy, etc. and previous manual removal of placentation. Now grading of CSP, so in reporting the cases of CSP we have to give grading. So there are 4 grades, grade 1 is when the GS is embedded in less than half thickness of the lower anterior corpus, grade 2 when it is extending to more than half thickness of the overline myometrium, grade 3 when the GS is bulging out of the cesarean scar and grade 4 when the CSP is amorphous tumor with rich vascularity at the cesarean scar. This is the grade 1 occupying less than half of the anterior corpus and the image of the same and this is more than half of the anterior corpus and image of the same. Again this is grade 1, this is grade 2 and again this is grade 1 according to the thickness of the anterior myometrium involved. The grade 3 when it is bulging out of this scar, here we can see it bulging and the myometrium is so thin and this is the bladder and grade 4 is like an amorphous tumor, here also we can see it is like an amorphous tumor. This is the MR image of the same, again we can see this is grade 2, this is also grade 2, see how thinned out the anterior myometrium is and this is the reason for myometrial rupture if not diagnosed timely and this is grade 3 almost absent anterior myometrium in this sac is bulging out of the cesarean scar. This is the grade representation, the empty endometrial cavity, empty cervical canal and G sac in the region of the scar and this is the anterior trophoblastic flow. Again we can see sometimes we get a complete trophoblastic flow and usually we get anterior peritrophoblastic flow so here also we can see the anterior myometrial flow and flow in the fetus as well. Same here we can see the anterior trophoblastic flow which is very important here, again this is grade 2, here we can sometimes find the endometrial cavity which is empty but it is filled with slight fluid collection we can find here and definitely the sac here is bulging and occupying more than the half of the anterior corpus with thinning of the anterior myometrium and even more thinning as we follow it up. This is a short video showing the grade 1 CSP and also showing the negative sliding sign. What is the sliding sign? On gentle probe pressure there is known displacement in case of CSP and also in cases of cervical electronics. So this is negative sliding sign, non-displacement of the sac with gentle probe pressure. Similarly here also the negative sliding sign can be seen but with probe pressure we are not able to displace it which is helpful in differentiating with the failed pregnancies which I will show later on. So the differential diagnosis is very important. We have to have a very high suspicion index to diagnose CSP because often we misdiagnose them as cervical ectopic or failed pregnancies. So the points are the G is in the CSP is seen in the anterior lower uterine segment whereas in the cervical ectopic and failed pregnancy we find them within the cervical canal. The overline myometrium is thinned out in CSP and normal in cervical ectopic and failed pregnancy. Then again the sliding organ sign is negative in CSP and cervical ectopic as well and it is positive in failed pregnancy. Then on the Doppler examination we have a marked peritrophoblastic flow in CSP with high velocity and low PI values on pulse Doppler. And in cervical ectopic we have a slight vascular flow around the just like any other ectopic within the GS and around the GS and the failed pregnancy definitely we don't have any color flow. And on short follow up the size of the CSP and cervical ectopic will grow and in failed pregnancy it will not grow and it will be not fixed in the location. This is the cervical ectopic we can see it is in the midline perfectly normal anterior myometrium and our glass appearance of the uterus and the flow around the cervical ectopic. So very important is differentiating the CSPs from spontaneous or inevitable abortions. So spontaneous or inevitable abortions begin with more extensive bleeding right from the beginning from the detached corionic sac and most aborting patients complain of cramping pain in the lower abdomen and exhibit sometimes cervical motion tenderness. In contrast to the CSPs where we have mild or moderate lower abdominal pain and not so much extensive bleeding initially. Then Zircovich at all reiterated the importance of the absence of healthy myometrium between the bladder and the GSAC and added following criteria that on Doppler imaging the sac is well perfused in contrast to the avascular appearance of the aborting GSAC and the negative sliding Morgan sign that I have already mentioned. So here in this case this is the CSP with a very low plastic flow and then we are going to have negative sliding sign as well and no flow in this inevitable missed abortion and we'll have a sliding sign positive and internal loss may be open at times. We can also see that it is very low line not in the region of the scar or esthems. The complications are devastating. There can be placenta previa, acreta spectrum and studies have shown that if you follow up the CSPs they are going to land up in the placenta acreta spectrum in most of the cases. Then if you're going to follow up we can have a uterine or myometrial rupture because of thinning out and then leading to massive haemorrhage and haemorrhage shock which increases the maternal morbidity and mortality. So finally the take home message is early detection by TBS is the gold standard for management of CSPs for location of SAC, for abnormal placentation, allowing more treatment options and reducing the risk of complications. CSPs should be sought after in women with prior history of LSCS and low implantant gestational SACs and CSPs are associated with increased risk of PAS that is placenta acreta spectrum and maternal morbidity.