William J. Garrett

Fetal umbilical venous flow measured in utero by pulsed Doppler and B-mode ultrasound: I. Normal pregnancies

Umbilical venous blood flow was measured with a pulsed Doppler unit, which was used in combination with a B-mode ultrasonic imaging system to permit location of the umbilical vein and measurement of its cross-sectional area. The accuracy and limitations of the method are discussed. Forty-seven normal fetuses with gestational ages ranging from 22 weeks to term were studied on a total of 61 occasions. Flow increased with gestational age until 36 weeks, was maximal between 37 and 38 weeks, then decreased during the last 2 weeks of pregnancy. Flow per unit of fetal weight was constant during pregnancy until 36 to 37 weeks, when a reduction occurred.

Principles and classification of soft tissues by grey scale echography

Abstract Grey scale echography portrays the internal echoes originating from small impedance discontinuities formed by the structural organisation of soft tissue. These internal echoes are independent of inclination whilst their size and distribution is specific to the type of tissue examined. Thus normal and pathological tissues are portrayed with a differing appearance allowing their identification on the echograms. The principle of selecting a range of magnitudes of echoes for display on a restricted dynamic range of a display unit is described as well as methods used for compensating for the factors that effect the magnitude of echoes. Grey scale echography gives a new active role to simple scanning and a comparison of the features of simple and compound scanning is made. The simples and most reliable application of grey scale echography is the differentiation between cystic and solid structures and the criteria used in this application are discussed. The classification of soft tissue is more difficult, normal soft tissues being classified primarily by the appearance of the internal echoes, whilst the classification of localized pathological processes is based on the appearance of both the internal and the boundary echoes. The diagnosis of diffuse pathological conditions is the most difficult and is based on the change in the normal structural echo pattern.

Placental aging monitored by gray scale echography

With gray scale ultrasonics echography, it is possible to identify changes in placental anatomy which formerly have been recognized only by examination of the placenta after delivery. By serial examinations these changes can be detected as they occur. The significance of the changes is discussed and an association between the premature appearance of aging of the placenta and a decline in placental function is noted.

Assessment of fetal size and growth rate by ultrasonic echoscopy.

Ultrasonic measurements of the size of the fetal head and trunk permit a fairly accurate estimate of gestational age in the middle trimester of pregnancy. Serial ultrasonic measurement of fetal size records fetal growth rate, which is of help in the management of gravidas with a history of previous intrauterine death, suspected placental insufficiency and, perhaps, diabetes mellitus. Small-for-dates or dysmature babies have been shown to acquire their low birth weight by one of two methods: either they grow at an evenly slow rate throughout pregnancy, or they grow normally to a point in the third trimester, after which growth stops altogether or proceeds at a much slower rate than normal.

Ultrasonic Two‐Dimensional Visualization for Medical Diagnosis

The spot size of the display unit may be used as the design criterion of the ultrasonic visualization system. Methods to design the transducer to comply with the criterion are presented, and the performance of the scanner and the receiver are discussed. The technique is prone to artifacts caused by axial and nonaxial multiple reflections, velocity changes in tissue, and signal processing. Echograms of the pregnant uterus are used to illustrate the application of the technique.

Selection of Patients by Ultrasonic Echography for Fetal and Immediate Neonatal Surgery

Garrett, W. J. and Kossoff, G. (1976). Aust. paediat. J., 12, 313–318. Selection of patients by ultrasonic echography for fetal and immediate neonatal surgery. Many congenital anatomical anomalies can be diagnosed by two‐dimensional grey scale ultrasonic echography in the fetus and neonate at an earlier stage than has hitherto been possible. This information allows immediate neonatal surgery to be undertaken and demonstrates the possibility of the intrauterine surgical relief of obstructive conditions. Illustrative examples are given.

Ultrasonic Film Echoscopy for Placental Localization

Summary: A different ultrasonic appearance of the placenta is seen when film echography is used instead of the standard storage tube echoscopy. Film echography gives more detailed information about the placenta and makes localization uniformly successful.

Gray Scale Ultrasonic Investigation of Focal Defects on 99mTc Sulphur Colloid Liver Scanning1

Radionuclide liver scanning, though a well established technique for the detection of normal liver tissue replacement, has yet to deliver a satisfactory isotope method for distinguishing the benign or malignant nature of a disclosed nonfunctioning area. The solid or cystic nature of focal areas of replacement can be shown by ultrasonic echography, so the malignancy of the area can be inferred. The complementary use of both techniques is recommended.

Early Growth Retardation in the First Trimester: Is it Characteristic of the Chromosomally Abnormal Fetus?

Summary: There have been recent reports on a small number of cases which suggest that the detection of early growth retardation might allow recognition of the chromosomally abnormal fetus in the first trimester of pregnancy. To amplify these observations, the crown‐rump length (CRL) measurements between the 64th and 86th day of menstrual age were determined in (a) 500 control high risk patients in whom a normal karyotype was subsequently demonstrated by chorionic villus sampling (CVS) and (b) 25 chromosomally abnormal fetuses. The data indicate that early growth retardation, as expressed by a small CRL measurement, is not a special characteristic of the chromosomally abnormal fetus in the first trimester of pregnancy. The CRL measurement is therefore not a useful marker or screening test at that time, except perhaps for triploidy. The well documented growth retardation with trisomy 21 and trisomy 18 which has been observed in the second trimester does not begin until after the 12th week of menstrual age.

Octoson — A New Rapid General Purpose Echoscope

A new multi-purpose ultrasound scanner has been designed from experience, both technical and clinical, gained from over 12 years usage of various scanners. These have covered the areas of obstetrics, gynecology, breast, thyroid, abdominal organs and the brain in children1–5. The unit was designed around the following objectives in order to improve on presently used skin contact scanners and water coupling echoscopes.