 Today, we will see the part 2 of 11 to 14 week scan that is the structural analysis. As we saw in the previous video, if you are doing a structural analysis as a part of early anomaly scan, it is best to do it between 12 to 13 weeks or 13 to 14 weeks. 11 to 12 week scanning can have some challenges while doing a structural scan. There are ISOG guidelines regarding the 11 to 14 week scan, but as you can see these were published in 2013. There are lot of additional information which is now available about the 11 to 14 week scan. So we will see the guidelines plus some additional points. So what do the guidelines say? In head, what are we supposed to see whether it is present or not, the cranial bones ossification, the midline fachs, the coroid plexus filled ventricles. In the neck, you have to see the normal appearance and vehicle transducency by a trained or certified operator. In the face, we are supposed to see eyes with lens, the nasal bone, normal profile and mandible and intact lips. Wherever they have put this asterisk, these are optional and they have not made it mandatory. But as we know that nasal bone, normal face profile, all these can be seen very easily in our anomaly scan at 11 to 14 weeks. Lips are of course difficult to see. In spine, we are supposed to see vertebrae in longitudinal and axial and intact overlying skin. Again, they have put it as part of the optional thing. But we know by our experience now that it is very easy to scan the spine and the intact overlying skin. In the chest, we see symmetrical lung fills, no effusion or masses. The heart, we look at cardiac regular activity and four symmetrical chambers. Nowadays, we also look at the two outlaw tracks forming a V. We will see that subsequently. In the abdomen, we look at the stomach, bladder and kidneys are optional. But 12 weeks in transabdominal scan, the kidneys may not be seen. Most of the time, the bladder is seen beyond 12 weeks. Abdominal wall, we look at normal cord insertion. That is no umbilical defects. In extremities, we look at four limbs, each with three segments. Hands and feet with normal orientation, again that is optional. So, you should remember all those with the asterisk or which are highlighted are the optional ones according to these guidelines. Placenta and cord, of course, has to be seen and not just the fetus. About the biometrics, generally what we measure is BPD, HC, AC and FL and of course the CRL. CRL measurement, again, is at the two mid-saturated scanning. And then from head to the rump, you take the maximum measurement, whatever comes. Then, we start from the head to toe, the analysis of the fetus. Like in 20 weeks anomaly scan, even here in the head, we have three planes and these are the different structures which you can see at the different planes. So, if you look at the plane one, you should see a midline fox, oval head shape and ossification. You should see the chloride flexes, completely filling the ventricles. The third ventricle, the cortex is very minimal at the periphery and not really very well appreciated. In plane two, you should see the fox anteriorly. The thalamai and the cerebral peduncles are seen together and the aqueduct of sylvius is something where the arrow is seen. This is where the aqueduct is seen very well. In 11 to 14 weeks scan, the aqueduct, you see it very prominently. In plane three, it is the developing cerebellum, the fourth ventricle, that is the IT, future cisterna magna. These are the structures which we tend to see in the sagittal section better. So, this is how we scan the head right from the plane one to plane three and then once you start seeing the orbits here, you know, you scan the entire brain. So, this is what we normally look at the NT scan image. This is the normal NT and what you see here is the IT. This is the brain stem. This is thalamai and midbrain. This is the occipital bone. This is the corret plexus in the fourth ventricle and this is the future cisterna magna. So, there are the normograms which are available but the mean is around 1.7 millimeter. The depth of the IT is 1.7 millimeter mean. You can remember it as just 2 millimeter. So, when you're looking for the NT section, you tend to see the IT very well. What you see generally is what strikes you is these echogenic lines. This is the upper border of the brain stem. This is the lower border of the brain stem. This is the corret plexus of the fourth ventricle and this is the occipital bone. So, these are the four bright lines of the three leucenses which you tend to see in your routine NT image. And this is where the IT comes. So, if you take a ratio, you take a brain stem diameter and then you take brain stem to occipital bone distance. Then there is a ratio described BS to BS OB ratio that is AB upon BC. So, there are some normograms available for all these measurements but again, as I said, it is usually eyeballic. The abnormalities, we are not going into detail right now. We'll do that in the subsequent videos. From here from the head, we come to the face. So, this is where you see eyes, the orbits, the maxillary process and the nose. The tip of the nose is seen here. In the coronal section like this, you get this section of the retro nasal triangle. This is something like a PMT in 21 week scan. This is the nasal bone. These are the orbits at the sides. These are the maxillary processes. This is the maxilla alveolar ridge where the cleft palate will be seen. This is the mandible and this is the mandibular gap or this is the gap which you should see always. Another important aspect in the sagittal scan is this is what normally we see and this is the palate. So, whenever there is a cleft, something like this, this will not be intact. As you can see here, this is normal where the palate is intact. This equationic line is intact and here there is a break. So, this will be seen in a profile view in a lateral sagittal view. With that, we come to the chest. In the chest, what we see is two lungs, the right ventricle, the left ventricle. In color, you will see both inflows which are equal. This should be equal in size and of course, you can make out the cardiac axis. If you come to the upper mediastinum, what you see is something like a three vessel view where you get the pulmonary artery, the aorta and the SVC and of course, you tend to see trachea here. And once you put the color on, you see these both outflows forming V to the left of the trachea. So, this is what you will see in the chest. Then when you come to the abdomen, again, there are three planes. You will see stomach in this transverse section on the left side. If you make a little oblique sagittal section, you will see stomach and the bladder. As I said, beyond 12 weeks, most of the times the bladder is visualized. The two umbilical arteries are seen in this section. An intact abdominal wall can be seen in this transverse abdominal section, the lower abdomen or you can see it in the sagittal section. And in fact, this is the umbilical arteries go here and the umbilical vein comes here and this is the ductus venousis. Then when you come little posteriorly, again, a coronal section, what you see here, in fact, are the kidneys. This is a TBS scan. Transseptominally, it might be a little difficult. These are the lungs here. These are the ribbed shadows and the spine, which is seen here. And these two are the pelvic bones, what you see there down. So, this is a little coronal posteriorly when you are seeing it. Then we come to the extremities. The upper limbs, again, you should see the hands and fingers, the middle segment and the proximal segment. You always tend to see both humerus, radius ulna and then the fingers like this. Fingers are always outstretched. In fact, counting fingers is easy at this stage. But again, in an obese individual, it might be difficult. This is the lower limbs. What you see is the foot, the middle segment and the proximal segment, both femur, then the middle segment and the foot. So, all that should be seen from that head to toe section. This is the sagittal section more posteriorly, where you will see the intact skin and this is the spine. So, this section comes better when the fetus is facing back up and then you will see this intactness of the skin and the spine. Spine is just seen as two line structure, two echogenic lines like this. What you should not forget is the other intra or extra uterine structures, the placenta, cervix, any sub-choreonic fluid collections. Position of the placenta in relation to the cervix is of less importance at this stage. Most migrate away from the internal cervical ores because we are doing it very early at 12 to 13 weeks. So, placenta previa should not be reported at this stage unless it is completely covering the ores or there is a history of bleeding PV and then in such patients reporting it might be worthwhile. Special attention should be given to patients with the prior caesarean section who may be predisposed to scar pregnancy or placenta acreta with significant complications. Other gynecologic pathologies like uterine shape anomalies, gliomyomas which tend to increase in size during pregnancy, they can be a cause of pain. Any adnexa lesions that also you should see, you should scan globally the lower abdomen and try and see the other structures which are outside the uterus or in the adnexa. One should always include uterine artery evaluation at 11 to 14 weeks scan for the risk of preeclampsia. It is taken at the societal section at the level of cervix. The internal os is identified. Colour Doppler is put on to identify each uterine artery with the slight tilting of the probe to each side. The PW gate is fixed at two millimeter and the angle of insolation should be less than 30 degrees. Right and left, both of the uterine arteries are insulated and mean PI is calculated. You should always remember that the prediastolic notch will be present at this stage but the mean PI is the value which is important. The normograms are available but the 95th percentile cutoff of 2.35 is easy to remember. Problems, well yes, problems can be plenty especially in obesity's because of fetal position because of previous LSEs. Sometimes it is acutely retroverted uterus. So what happens is in most of these patients doing a transvaginal scan always helps. If the patient has had previous LSEs, sometimes the uterus is really vertically oriented, the cervix is really become elongated and then you can't get a very good image by TVS. In such patients, high frequency linear or convex transducers might help but I find the endovaginal scanning the best most of the times especially when I suspect some abnormality. In these patients, of course, the waiting time of the patient increases. You make the patient wait for some time, see it after one hour, sometimes in the evening, sometimes maybe call the patient the next day and see again but one thing is sure, a systematic scanning from head to toe like a 20 week scan, if you start doing it the way you do a 20 week scan, a lot of anomalies can be picked up even during 11 to 14 week scan. Sometimes the additional scan after few days depending on gestational age may be needed especially if you suspect some abnormality. You're not sure whether there is a problem, there is no problem, you're not seeing the fetal stomach, it is very small, you feel that there is a problem in the heart so at such times especially in an obese patient, sometimes we have to tell the patient to come after a week where the fetus will be slightly bigger size and you will be able to see that fetus better. And of course you have to explain the limitations to the patients and mention in the report in difficult evaluation. You can talk to the consult gynecologist if you're not seeing certain structures because of the position or even after trying for one day or two days then you can mention it in the report so that at least in the next anomaly scan these things can be seen properly. We have not covered the anomalies system wise, we will do that in the subsequent videos but this is how you do a normal structural analysis at 11 to 14 weeks care. Thank you.