PLATSENTOGRAFIYA (Latin placenta, from Greek plakus flat cake + Greek grapho to write, represent) — detection of the place of an attachment, the sizes and structure of a placenta by means of methods of radiological, radio isotope and ultrasonic diagnosis.
In obstetric practice of P. apply hl. obr. at suspicion on placental presentation (see) and for definition of its localization before carrying out amniocentesis (see). It is more preferable to carry out P. after the 34th week of pregnancy. The safest and reliable method P. is ultrasonic echolocation of a placenta (see. Ultrasonic diagnosis ). Radio isotope and, especially, rentgenol, methods P. apply seldom, in connection with danger of impact of ionizing radiation on mother and, mainly, on a fruit.
To rentgenol, to methods P. carry: a survey X-ray analysis of an abdominal cavity of the pregnant woman, a X-ray analysis of an abdominal cavity against the background of the bladder contrasted by gas, intravenous P., an angiography of a placenta and some other methods.
The survey X-ray analysis of an abdominal cavity is made in a side projection. Use the special wedge-shaped filters leveling the optical density of a picture to improvement of quality of the image. On the roentgenogram the placenta forms a shadow in the form of a half moon, adjacent to a wall of a uterus. At a hydramnion, a multiple pregnancy, regional and side placental presentation this method not always allows to define its situation. In these cases the X-ray analysis of an abdominal cavity is carried out after administration of gas to a bladder (see. Pregnancy, X-ray inspection at pregnancy , Tsistografiya ).
The image of a placenta on the roentgenogram can be received also in 6 — 8 sec. after administration of triyodirovanny contrast medium (triombrin and dr). in a superficial vein of front elbow area (intravenous P.).
The most sharp image of a placenta is received with the help angiography (see). The Triyodirovanny contrast agent is entered into an aorta at the level of an otkhozhdeniye from it an ovarian artery by transdermal puncture catheterization of a femoral artery. This method allows to receive the contrast image of a placenta on serial roentgenograms.
Radio isotope (radionuclide) P. is carried out with the help radio-pharmaceuticals (see). The pregnant woman intravenously administer the high-molecular drug (albumine of human serum), marked radionuclides 99m Tc, 113 In or 131 I. Due to the high intensity of blood circulation in a placenta large molecules of marked albumine quickly collect in its intervillous space, without getting into a blood stream of a fruit. In 5 — 10 min. after administration of drug make stsintigrafiya (see) or scanning (see) in direct and side projections. The image of a placenta on skano-is normal and stsintigramma it falls on area of an uterine fundus (fig., a). At the central (full) placental presentation it is located directly over a pubic symphysis (fig., b), and at incomplete (regional or side) presentation — is displaced aside. Accuracy of recognition of placental presentation by means of this method is much higher, and radiation of a fruit in several tens of times is less, than at rentgenol, methods P.
Bibliography: Kasatkin Yu. N. and d river. Radio isotope visualization of a placenta, Medical radio-gramophones., No. 4, page 38, 1977; M of l y p-kov X. and Ignatov A. Clinical value of a placental stsintigrafiya, No. 12, page 67. 1977; A a n t and and To. On the use of X-rays and ultrasound in locating the placenta, Ann. Chir. Gynaec. Fenn., y. 61, p. 197, 1972; Fournier D. u. a. Radiologisohe, sonographische und thermo - graphische Verfahren zur Plazenta-Lokali-sation, Rontgenpraxis, Bd 28, S. 290, 1975; HodgeK.E. Gravitational placentography, .Radiology, v. 68, p. 637, 1957; Johnson P h. K i n g D. The placenta, evaluation by radionuclides and ultrasound, Semin, nuci. Med., v. 4, p. 75, 1974; Snow W. Roentgenology in obstetrics and gynecology, Springfield, 1952.
V. V. Kitayev.