Talk:Ultrasound

A fast automatic recognition and location algorithm for fetal genital organs in ultrasound images

J Zhejiang Univ Sci B. 2009 Sep;10(9):648-58.

Tang S, Chen SP.

Post-Doctoral Research Station, Shenzhen University, Shenzhen 518060, China. Abstract Severe sex ratio imbalance at birth is now becoming an important issue in several Asian countries. Its leading immediate cause is prenatal sex-selective abortion following illegal sex identification by ultrasound scanning. In this paper, a fast automatic recognition and location algorithm for fetal genital organs is proposed as an effective method to help prevent ultrasound technicians from unethically and illegally identifying the sex of the fetus. This automatic recognition algorithm can be divided into two stages. In the 'rough' stage, a few pixels in the image, which are likely to represent the genital organs, are automatically chosen as points of interest (POIs) according to certain salient characteristics of fetal genital organs. In the 'fine' stage, a specifically supervised learning framework, which fuses an effective feature data preprocessing mechanism into the multiple classifier architecture, is applied to every POI. The basic classifiers in the framework are selected from three widely used classifiers: radial basis function network, backpropagation network, and support vector machine. The classification results of all the POIs are then synthesized to determine whether the fetal genital organ is present in the image, and to locate the genital organ within the positive image. Experiments were designed and carried out based on an image dataset comprising 658 positive images (images with fetal genital organs) and 500 negative images (images without fetal genital organs). The experimental results showed true positive (TP) and true negative (TN) results from 80.5% (265 from 329) and 83.0% (415 from 500) of samples, respectively. The average computation time was 453 ms per image.

PMID: 19735097 http://www.ncbi.nlm.nih.gov/pubmed/19735097

Fetal volume and crown-rump length from 7 to 10 weeks of gestational age in singletons and twins

Martins WP, Nastri CO, Barra DA, Navarro PA, Mauad Filho F, Ferriani RA. Eur J Obstet Gynecol Reprod Biol. 2009 Jul;145(1):32-5. Epub 2009 Apr 21. PMID: 19386409

"Twins and singletons had similar fetal volume and crown-rump length between the 7th and 10th week of gestational age. Additionally, fetal volume assessed by VOCAL was better than crown-rump length to estimate the gestational age at the evaluated period. However, the improvement was small and probably without clinical significance. CONDENSATION: Fetal volume and crown-rump length were similar between singletons and twins. Fetal volume relative increase was higher and the predicted gestational age was better."

Fetal crown-rump length and estimation of gestational age in an ethnic Chinese population

Sahota DS, Leung TY, Leung TN, Chan OK, Lau TK. Ultrasound Obstet Gynecol. 2009 Feb;33(2):157-60. PMID: 19115262

"The best-fit equation for the sonographic estimate of gestational age (GA, in days) from CRL (in mm) was GA = 26.643 + 7.822 x CRL(1/2)(R(2) = 0.96). The mean difference between menstrual age and the predicted gestational age was 0.22 days (95% CI, - 0.14 to 0.56), which was lower than that of the three established CRL dating formulae. CONCLUSION: We have derived a formula suitable for the dating of naturally conceived pregnancies between 6 and 15 weeks of gestation that has no systematic prediction error (the 95% CI of mean difference between predicted and menstrual age included zero), comparing favorably with established CRL dating formulae."

Fetal size in the second trimester is associated with the duration of pregnancy, small fetuses having longer pregnancies

Johnsen SL, Wilsgaard T, Rasmussen S, Hanson MA, Godfrey KM, Kiserud T. BMC Pregnancy Childbirth. 2008 Jul 16;8:25. PMID: 18627638 | BMC

Functional linear discriminant analysis: a new longitudinal approach to the assessment of embryonic growth

Bottomley C, Daemen A, Mukri F, Papageorghiou AT, Kirk E, Pexsters A, De Moor B, Timmerman D, Bourne T. Hum Reprod. 2009 Feb;24(2):278-83. Epub 2008 Oct 31. PMID: 18978027 | Hum Reprod.

Fetal age assessment based on 2nd trimester ultrasound in Africa and the effect of ethnicity

Salpou D, Kiserud T, Rasmussen S, Johnsen SL. BMC Pregnancy Childbirth. 2008 Oct 30;8:48. PMID: 18973673

• Ultrasonic evaluation of fetal limb growth. Jeanty P, Kirkpatrick C, Dramaix-Wilmet M, Struyven J. Radiology. 1981 Jul;140(1):165-8. PMID: 7244221

Nontraditional sonographic pearls in estimating gestational age

Gottlieb AG, Galan HL. Semin Perinatol. 2008 Jun;32(3):154-60. Review. PMID: 18482614

"This chapter focuses on nontraditional fetal ultrasound measurements, including the transverse cerebellar diameter, fetal foot length, ratios of biometric and nonbiometric measurements, epiphyseal ossification centers, amniotic fluid volume, placental grading, and other miscellaneous markers in the context of evaluating a fetus with possible intrauterine growth restriction."

Terms

• Crown-Rump Length (CRL)

• Functional linear discriminant analysis (FLDA) - new growth assessment technique using serial measurements to discriminate between normal and abnormal fetal growth.

• Gestational sac (GS) size

• Linear discriminant analysis (LDA) to longitudinal data (James and Hastie, 2001)

• Mean gestation sac diameter (MSD)

• Mean yolk sac diameter (MYD)

• Transvaginal scan (TVS)

• Termination of pregnancy (TOP)