Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5802_Библиотеки_им_академика_М_И_Перельмана.pdf
Obstetrics
306
7 129
8 133
9 137
10 141
11 145
12 149
13 152
14 156
15 159
16 161
17 164
18 166
19 168
20 170
21 171
22 172
23 173
24 173
25 174
26 174
27 173
28 173
29 172
30 170
31 169
Embryonic/fetal heart rate (1st trimester)
32 167
33 165
34 163
35 160
36 157
37 154
38 151
39 147
40 144
FURTHER READING
Hanprasertpong T, Phupong V. First trimester embryonic/fetal heart
rate in normal pregnant women. Arch Gynecol Obstet. 2006;
274:257–260.
Papaioannou GI, Syngelaki A, Poon LC, Ross JA, Nicolaides KH.
Normal ranges of embryonic length, embryonic heart rate,
gestational sac diameter and yolk sac diameter at 6–10 weeks.
Fetal Diagn Ther. 2010; 28:4:207–219.
307
Obstetrics
308
Crown rump length
PREPARATION
Empty bladder for transvaginal imaging. Full bladder for transabdominal imaging in 1
POSITION
According to the mode of scan, transabdominal or transvaginal, the
mother will be in supine or lithotomy position. Midsagittal image
through embryo is obtained.
TRANSDUCER
Transabdominal: 3.0–6.0 MHz curvilinear transducer.
Transvaginal: 5.0–8.0 MHz transducer.
METHOD
When < 7 weeks gestational age, the crown and rump cannot be visualized separately; therefore, the greatest length of the embryo is measured.
When > 7 weeks gestational age, the sagittal section of the embryo is
taken and the longest length between the crown and rump is taken,
excluding the extremities and yolk sac.
APPEARANCE
“Figure of 8” shape solid density within gestational sac.
MEASUREMENTS
st
and 2nd trimester.
2 5.7 12 7.4 31 10.0
3 5.9 14 7.7 33 10.2
4 6.1 16 8.0 35 10.4
5 6.2 18 8.3 37 10.6
6 6.4 20 8.6 40 10.9
7 6.6 22 8.9 43 11.2
8 6.7 24 9.1 46 11.4
9 6.9 26 9.4 49 11.7
10 7.1 28 9.6 53 12.0
Crown rump length
The solid density within the gestational sac is measured in the longest distance (cursors).
FURTHER READING
Hadlock FP, Shah YP, Kanon DJ, Math B, Lindsey JV. Fetal
crown-rump length: Re-evaluation of relation to menstrual age
(5–18 weeks) with high-resolution real-time US. Radiology.
1992; 182:501–505.
309
Obstetrics
310
Discriminatory levels for diagnosis
of pregnancy failure in rst trimester
(transvaginal ultrasonography)
PREPARATION
Empty bladder for transvaginal imaging.
POSITION
Mother is in the lithotomy position. Sagittal and transverse images of
the endometrial stripe are obtained.
TRANSDUCER
Transvaginal 5.0–8.0 MHz transducer.
METHOD
Mean sac diameter (MSD), crown rump length (CRL), and fetal heartbeat are taken as described.
APPEARANCE
• Embryo: “Figure of 8”–shaped solid structure within the gesta-
tional sac.
• Gestational sac: Fluid collection with high-reective rim embed-
ded within the endometrium.
• Yolk sac : Spherical cystic structure with well-dened, high-reec-
tive margin lying within the gestational sac.
MEASUREMENTS
Findings diagnostic of pregnancy failure
1. CRL of ≥ 7 mm and no heartbeat
2. MSD of ≥ 25 mm and no embryo
3. Absence of embryo with heartbeat ≥ 2 weeks after a scan that
showed a gestational sac without a yolk sac
4. Absence of embryo with heartbeat ≥ 11 days after a scan that
showed a gestational sac with a yolk sac
Findings suspicious for, but not diagnostic of, pregnancy failure
1. CRL of < 7 mm and no heartbeat
2. MSD of 16–24 mm and no embryo
3. Absence of embryo with heartbeat 7–13 days after a scan that
showed a gestational sac without a yolk sac
4. Absence of embryo with heartbeat 7–10 days after a scan that
showed a gestational sac with a yolk sac
Discriminatory levels for diagnosis of pregnancy failure in rst trimester
The yolk sac (cursors) lying within the gestational sac.
5. Absence of embryo ≥ 6 weeks after last menstrual period
6. Empty amnion (amnion seen adjacent to yolk sac, with no visible embryo)
7. Enlarged yolk sac (> 7 mm)
8. Small gestational sac size in relation to the size of the embryo (<
5 mm difference between MSD and CRL)
FURTHER READING
Doubilet PM, Benson CB, Bourne T, Blaivas M. Society of
Radiologists in Ultrasound Multispecialty Panel on Early First
Trimester Diagnosis of Miscarriage and Exclusion of a Viable
Intrauterine Pregnancy. Diagnostic criteria for nonviable
pregnancy early in the rst trimester. Ultrasound Quarterly.
2014; 30:3–9.
311
Obstetrics
312
Nuchal translucency thickness measurement
PREPARATION
Full bladder for transabdominal imaging and empty bladder for transvaginal imaging.
POSITION
According to the mode of scan, transabdominal or transvaginal,
mother will be in supine or lithotomy position. Midsagittal image
through embryo is obtained.
TRANSDUCER
Transabdominal 3.0–6.0 MHz transducer.
Transvaginal 5.0–8.0 MHz transducer.
METHOD
Performed at:
Gestational age (GA) between 10 weeks + 3 days to 13 weeks + 6days
OR
Crown rump length (CRL) between 38 mm and 84 mm.
Fetus must be in the midsagittal plane. The image is magnied, so that
it is lled by the fetal head, neck, and upper thorax. The fetal neck must
be in the neutral position. Amnion must be seen separate from dorsal
fetal skin edge. The margins of the nuchal translucency (NT) edges must
be clear. Calipers must be placed on the inner borders of the nuchal line
perpendicular to the long axis of the fetus at the maximum thickness.
The largest of at least three good-quality measurements is taken.
APPEARANCE
Cystic area in the soft tissue posterior to the occiput.
MEASUREMENTS
Increased NT thickness for CRL is suggestive of chromosomal disorders (especially Trisomy 21), major defects of the heart and great arteries, cystic hygroma, twin-to-twin transfusion syndrome, and skeletal
dysplasia.
38 2.2
84 2.8
Nuchal translucency thickness measurement
The cursors detail the position for measuring the nuchal thickness. Normal nuchal
translucency increases with crown rump length and gestational age.
FURTHER READING
Ayras O, Tikkanen M, Eronen M, Paavonen J, Stefanovic V.
Increased nuchal translucency and pregnancy outcome: A
retrospective study of 1063 consecutive singleton pregnancies
in a single referral institution. Prenatal Diagnosis. 2013;
33:856–862.
Hyett J, Perdu M, Sharland G, Snijders R, Nicolaides KH. Using
fetal nuchal translucency to screen for major congenital cardiac
defects at 10–14 weeks of gestation: Population based cohort
study. BMJ. 1999; 318:81–85.
Pajkrt E, van Lith JMM, Mol BWJ, Bleker OP, Bilardo CM.
Screening for Down’s syndrome by fetal nuchal translucency
measurement in a general obstetric population. Ultrasound
Obstet Gynecol. 1998; 12:163–169.
Sheppard C, Platt LD. Nuchal translucency and rst trimester risk
assessment: A systematic review. Ultrasound Quarterly. 2007;
23:107–116.
313
Obstetrics
314
Nuchal fold thickness measurement
PREPARATION
Full bladder for transabdominal imaging.
POSITION
Mother is in the supine position.
TRANSDUCER
Transabdominal: 3.0–5.0 MHz curvilinear transducer.
METHOD
Fetal transcerebellar plane displaying cavum septum pellucidum, atria
of lateral ventricles, cerebral peduncles, and cerebellar hemispheres.
Maximum distance is taken from the outer skull table to the outer skin
edge. Performed between 14 and 24 weeks’ gestation.
APPEARANCE
Thickening of soft tissue of the neck posterior to the occiput.
MEASUREMENTS
16 4.2
17 4.6
18 5.0
19 5.3
20 5.6
21 5.8
22 5.8
23 5.9
24 5.9
Nuchal fold thickening has a high specicity for aneuploidy in the second trimester.
The most commonly accepted denition of “thickened” is a nuchal
fold of 6 mm or greater at 15–20 weeks; however, the 95
th
percentile
Nuchal fold thickness measurement
The position of measurement (between cursors) for the nuchal fold thickness.
measurement at 24 weeks also remains less than 6 mm. Thickening of
the NF has greater than 99% specicity for Down syndrome.
FURTHER READING
Reddy UM, Abuhamad AZ, Levine D, Saade GR. Fetal imaging:
Executive summary of a joint Eunice Kennedy Shriver National
Institute of Child Health and Human Development, Society for
Maternal-Fetal Medicine, American Institute of Ultrasound in
Medicine, American College of Obstetricians and Gynecologists,
American College of Radiology, Society for Pediatric Radiology,
and Society of Radiologists in Ultrasound Fetal Imaging
Workshop. Obstet Gynecol. 2014; 123:1070–1082.
Singh C, Biswas A. Impact of gestational age on nuchal fold
thickness in the second trimester. J Ultrasound Med. 2014;
33:687–690.
315