[Music] hello welcome to sonography Radiology training Channel this series of videos is about fatal biometry and growth this is the second video in this video series with title of fetal volumetry part 2. what is the outline of this presentation in general I will speak about second and third trimester dating in this video including these sections first introduction fatal head measurements fetal abdomen measurements fatal femur measurement and practical Point according to my experience the first section is Introduction during the second and third trimesters of pregnancy measurements of specified fetal ports can be used individually or in combination to estimate gestational age of pregnancy the most commonly used measurements for gestational a assignment are by parietal diameter occipital frontal diameter head circumference abdominal diameter abdominal circumference and femoral length now fetal head measurements the by parietal diameter occipital frontal diameter and head circumference are measured on an axial image of the fetal head at the level of pertolami third ventricle and Calvin septum placidin also we can see in this axial view bilateral chloride plexuses and false slippery as a continuous academic line which interrupted by carbon septumplicidum with a true axial view the calvarium and intracranial contents appear symmetric on either side of the fox and bird Ptolemy the BPD is measured by placing the caliper closer to the transducer that is at the top of the image at the outer edge of the Bony calvarium while the caliper further from the transducer should be placed on inner Edge of the Bony calvarian that is the biparticletonal diameter is measured from Leading Edge to Leading Age of the calvarium improper measurements either from using an image at incorrect playing or section through the fetal head or from misplacement of sonographic calipers relate to errors in estimating gestational age and Fetal weight the occipital frontal diameter and head circumference can be measured on the same view of the fetal head as the bipariable diameter provided the image through axial view that includes the entire head from the frontal bone to the occipital bone for the ofd measurement 1 caliper is placed in the anterior midline in the middle of the echogenic line of the frontal bone and the second second is placed in the middle of the echogenic line of the occipital bone and this is the occipital frontal diameter the head circumference is measured by using elliptical calipers to outline the outer edge of this skull the HC can also be calculated from the bipariate all diameter and ofd by this formulae means head circumference equals to 1.62 multiplied by the summation of these two diameters the oft is also used in conjunction with the BPD to take into account the shape of the fetal head a standard shape fetal head has an ofd BPD ratio of 1.265 when the oft BPD ratio is higher or lower than 1.26 5 a corrected BPD can be calculated from this formula means corrected BPD equals to a square root of the BPD multiplied by ofd divided by 1.265 the corrected PPD represents the BPD of the standard shaped fetal head with the same cross-sectional area another index of fetal head measurements is cephalic index cephalic index equals to BPD divided by ofd multiplied by 100 the cephalic index gives an area of the fetal head shape it can change according to various situations such as presentation for example Bridge presentation ruptured membranes and presence of a twin pregnancy the usual range is variable depending on various sources and different demographic groups often the mean value is taken is 78 with range of 74 to 83 grossly decreased cephalic index such as golicocephali while a grossly increased one can suggest brachiocephaly another section is fertile abdomen measurements there are two methods for AC measurement directly with ellipse calipers to calculated from linear measurements made perpendicular to each other usually the anthroposterior abdominal diameter and transverse abdominal diameter the abdominal diameters and abdominal circumference are measured on an axial image of the fetal abdomen at the level of the stomach and the intra hepatic portion of the umbilical vein the abdomen should be as round as possible and the kidney should not be visible for the abdominal diameters to perpendicular measurements are taken with the calipers placed on outer surface of the skin the anteroposter your abdominal diameter is measured from the anterior midline to the posterior midline which the ladder is located behind the spine and this is the AP diameter the transverse abdominal diameter is measured perpendicular to the AP diameter with the calipers placed on the skin surface on both sides of the fetal abdomen the abdominal circumference is measured via elliptical calipers outlining the outer surface of the skin around the abdomen the AC can also be calculated from two orthogonal abdominal diameters measurements as the abdominal circumference equals 1.57 multiplied by the summation of these two diameters when measuring the fetal abdomen curve must be taken to make sure the image is at the correct level the entire abdomen is included on the image the outer skin is visible and the calipers are placed appropriately images showing parts of a kidney are too low in the abdomen and will yield in accurate estimations of fetal age and weight misplacement of the calipers inside the fetal skin or the abdomen and will lead to underestimation of the gestational age and weight now fetal femur measurement the measurement of the fetal femur is actually a measurement of femoral diaphysis because for most of pregnancy only the diaphysis of the bone is ossified for most accurate femur measurements an attempt should be made to image the femur as perpendicular to the transducer beam as possible but an angle of insulation between 45 and 90 is typical on the image the femur is measured by placing the calipers at either end of the earthified the offices it's important not to include any of the femoral epiphysis which can appear as a linear projection from the proximal or distal end of the diaphysis now please pay attention to this practical teaching points although taking these images and standard measurements seems simple it's sometimes challenging in pregnant women who are overweight or in cases where there is uterine contraction or the fetus in a prone position obtaining standard images is sometimes very difficult and challenging as you can see in this clip it will be sometimes very difficult to obtain a standard abdominal circumference view in a prone fetus and in this clip the same problem in doing pregnancy therefore enough time should be spent for proper and standard measurements sometimes it's necessary for a pregnant woman to get off the bed and walk for a few minutes in order to obtain standard images now I suggest two orders of my videos that are close to this video in terms of matter thank you for your attention