RAJIV GANDHI UNIVERSITY OF HEAL TH SCIENCE BANGALORE.KARNATAKA

ANNEXURE- II

PROFORMA FOR THE REGISTRATION OF SUBJECTS FOR DISSERTATION

1 / Name Of The Candidate And Address / DR. AMMISETTY VENKATA KALYAN KUMAR
18-295 B- 7 ,NEERUGANTI STREET OLD TOWN ANANTAPUR.
ANDHRA PRADESH. 515001
2 / Name of the Institute / M. S. RAMAIAH MEDICAL COLLEGE, BANGALORE -560054.
3 / . Course Of Study And Subject / M D (RADIODIAGNOSIS)
4 / Date Of Admission To Course / 2nd MAY , 2008
5 / Title of the Topic / DETERMINATION OF GESTATIONAL AGE BY FETAL KIDNEY LENGTH
MEASUREMENT AFTER THE 20TH WEEK OF GESTATION IN HEALTHY WOMEN WITH UNCOMPLICATED PREGNANCY.

6BRIEF RESUME OF THE INTENDED WORK

6.1 NEED FOR THE STUDY

Accurate gestation age assessment is pivotal to quality maternity care, e.g. diagnosis of growth disorders and timing of delivery.Failure can result in iatrogenic prematurity or postmaturity , both being associated with increased perinatal morbidity and mortality .Historically, the dating of pregnancies was based on the first day of the last menstrual period (LMP) in a regular 28- day menstrual' cycle.

Since the introduction of diagnostic ultrasound, more reliable approaches to the dating of pregnancies have developed. These include gestational sac diameter and volume and crown rump length measurement in the first trimester. Crown rump length measurement has been described to predict gestational age accurately to with in ± 4.7 days. In the second trimester, most commonly used biometric indices for dating pregnancies are the fetal biparietal diameter and femur length. However, other indices such as transcerebellar diameter, clavicle length and foot length, have also been used. Most of these methods can predict gestational age with a high degree of accuracy in the early second trimester. However, as gestational age progress, they become increasingly unreliable because of the biological variability of size in relation to age. Accurate dating of pregnancies in the late second trimester or in the third trimester therefore remains a problem, especially in women who consult late for maternity care and are uncertain of the date of their LMP .

By prenatal ultrasound, identification of either one or both kidneys is possible in 90% cases in the 17th week of gestation and in 95 % cases after 20th week. Although kidney size, as for all fetal organs, is affected by growth variations, these appear to predominately affect only anterior- posterior and transverse diameters. The length of kidney remains largely unchanged in small for gestational age fetus I. Knowledge of these measurements may allow earlier diagnosis of variety of renal abnormalities as well as accurate estimation of gestational age.

The present study is undertaken to validate the fetal kidney length measurement as an additional morphological measurement of fetal growth with less variability .This measurement is easy to take and can therefore be easily incorporated in to the model for dating pregnancies after 20 weeks of gestation, particularly when measurements of biparietal diameter and head circumference are difficult.

6.2 REVIEW OF LITERA TURE

Development of human fetal kid.ney runs through a series of continual and mutually dependent changes during which the kidney obtains its morphological ana functional maturity. The kidneys are situated on either side of lumbar spine and may be consistently visualized from about the fourteenth week. At this stage they have homogenous appearance similar to the liver and with lower reflectivity than the surrounding bowel. At this early stage they are readily demonstrated in a posterior transverse scan below the level of the liver. The renal pelvis may be seen as an echo-free, slit like space in the centre of the kidney.(3)

As pregnancy progresses further details of renal architecture appear .A thin reflective rim, representing the renal capsule, appears at about nineteenth week. From the 28th week, corticomedullary junction may be distinguished from the renal cortex and the hypoechoic renal pyramids are well delineated. The renal border may appear lobulated on the longitudinal image. These fetal lobulation gradually develop into a smooth border as the gestation progress. Accurate ultrasonic identification is not possible until approximately 15 weeks, due to their small size and lack of perirenal fat. As the kidney enlarge, they become progressively easier to identify, and by 30 weeks there is sufficient fat surrounding and accentuating the normal sonolucent renal parenchyma to make identification relatively simple.(4 )

It has been demonstrated that there exists strong correlation between fetal kidney length and gestational age as predicted by biparital diameter(r=0.81)), femur length(r=0.82), abdominal circumference (r=0.83) and average of the three. These measurements are not statistically different, and each can be used to correlate renal length. (5)

There is significant correlation between gestation age and fetal kidney length(r=0.94) as compared to other parameter biparital diameter (r=0.932), femur length (r=0.936), head circumference(r=0.932) and abdominal circumference (r-0.89) (2). A significant difference in the average fetal renal length is found when length are compared across the range of gestation 18 to 41 weeks .The mean kidney length increased from 2.2 +_0.2 cm at 18th week to 4.5 cm at 41 weeks. These measurements correlated well with still born fetus as well as premature infants, as determined by menstrual age.4 The inter and intraobserver variability for kidney length measurement were 2.4% and 1.5%- 3.5% respectively .(2)

Fetal kidney length is most accurate with standard error of 10.29 days in predicting gestation age as compared to the biparital diameter (11.62days), femur length (10.96days), head circumference (14.54days) and abdominal circumference (14.54 days). The best predictor of gestation age was

combining biparital diameter (BPD), femur length (FL), head circumference (HC), abdominal circumference (AC) and fetal kidney length (FKL)the accuracy of predicting gestation age was _+ 8.48 days as compared to without fetal kidney length (FKL) was _+ 9.48 days.(2)

No significant difference was found between right and left renal lengths in fetuses in whom both kidneys were imaged. No correlation was found between fetal renal length and paternal and maternal height and weight.

No significant differences in the dimensions of the fetal kidneys exist between

the different sexes.(6 )

HYPOTHESIS

Fetal kidney length measurements are effective in the evaluation of gestational age, by obstetric ultrasonography after 20th week of gestation till term.

6.3 OBJECTIVE OF THE STUDY

To perform obstetric ultrasonography in healthy women with uncomplicated pregnancy between 20th week of gestation and term to determine a correlation between the fetal kidney length and the gestational age as determined by the last menstrual period and other sonographic parameters like biparietal diameter, head circumference, abdominal circumference and femur length.

7 MATERIAL AND METHODS

7.1 SOURCE OF DAT A

At east 100 healthy women with uncomplicated pregnancy between the 20th week of gestation and term referred from the Obstetrics and Gynaecology department of M. S. Ramaiah Hospitals, Bangalore will be included in this study. The study period is for eighteen months; from November 2008 to June 2010.

7.2 METHODS OF COLLECTION OF DATA

Obstetric ultrasonography will be performed using GE-voluson 730 pro, Siemens Sonoline G50, GSO/ GB Logig 500 pro or Aloka SSD 900 ultrasound scanner using a 3.5 MHz convex probe.

Measurements are obtained in the sagittal plane, when full length of kidney with renal pelvis is visualized. Maximum length of anyone single fetal kidney is measured from upper pole to lower pole atleast thrice and mean of the measurements is taken.

Gestational age for the measured mean fetal kidney length, was determined as per the chart of the fetal size from the text book of clinical ultrasound in obstetrics and gynecology by David Cosgrove3.

INCLUSION CRITERIA

Healthy women with uncomplicated pregnancy between the 20th week of gestation and term.

EXCL USI ON CRITERIA

  1. Before 20 weeks of gestation age.
  2. Unknown or inaccurate date of last menstrual period.
  3. Irregular menstrual cycles.
  4. Oligohydramnios.
  5. Polyhydramnios.
  6. Diabetic mother.
  7. Pregnancy induced hypertension.
  8. Pre eclampsia.
  9. Multiple gestations.
  10. Fetal chromosomal abnormalities.
  11. Fetal anomalies.
  12. lntrauterine growth restriction.

7.3 DOES THE STUDY REQUIRE ANY INVESTIGATIONOR INTERVENTIONS TO BE CONDUCTED ON ,PATIENTS OR OTHER HUMAN OR ANIMALS?

Yes. Obstetric ultrasonography has to be performed on normal pregnant women.

Study Design

Hospital based prospective study.

Statistical Analysis

Gestational age obtained using fetal kidney length is compared with clinically determined gestational age and the determined mean ultrasound gestational age using 't' test and also the association between these parameters will be assessed using the correlation coefficient.

Gestational age obtained using fetal kidney length is compared with gestational age obtained from individual parameters such as biparietal diameter, head circumference, abdominal circumference and femoral length

Using 't' test and also the association among these parameters will be assessed using the correlation coefficient

7.4 HAS ETHICAL CLEARANCE BEEN OBTAINED FROM YOUR INSTITUTION IN CASE OF 7.3 ?

YES. The certificate of the same has been enclosed.

8. LISTS OF REFERNCES

  1. KonjeJC, Okaro CI, Bell SC, de Chazal R, Taylor Dl. A crosssectional study of changes in fetal renal size with gestation in Appropriate and small for gestational age fetuses. Ultrasound ObstetGynecol1997; 9: 35-7
  2. Konje J.C., K.R. Abrams, S.C. Bell, D.J. Taylor.Determination of gestational age after the 24th week of gestation from fetal kidney length measurements. Ultrasound ObstetGynecol 2002;19: 592-597.
  3. Meire.H, Cosgrove.D, Dewbury .K editors. Ultrasound in obstetrics and gynaecolgy. Newyork: Churchill livingstone 1992.
  4. Lawson T.L., W. Dennis Foley, L.L. Berland, K.E. Clark. Ultrasonic evaluation of fetal kidneys. Radiology 1981; 138: 153-156.
  5. Cohen H.L., J. Cooper, P. Eisenberg, F.S. Mandel,B.R. Gross, M.A. Goldman, E. Barzel, K.F. Rawlinson.Normallength of fetal kidneys: sonographic study in 397 obstetric patients. Am JRoentgenol1991 ; 157: 545-548
  6. Slobodan. vlajkovic, Ljilianavasovic, Radacukuronovic et al. Age related changes of human fetal kidney size. Cell tissue organs 2006; 182: 193-200.
  7. leanty P, Dramaix-Wilmet M, Elkhazen N, Hubinot C, van Regemorter N. Measurement of fetal kidney growth on ultrasound. Radiology 1982; 144: 159-62
  8. Bertagnoli.L, Lalatta.F, Gallicchio.R et al. quantitative characterization of growth of fetal kidney. J. Clinical ultrasound 1983;11: 349-356.

SIGNATURE OF THE STUDENT:

REMARKS OF THE GUIDE: Determination of gestational age by fetal kidney length is quite relevant as this parameter is less influenced by extrinsic factors. This is an attempt to validate this parameter as an alternative to commonly used fetal biometry.

Name and Designation of the Guide: DR. ASHOK KUMAR. A.

Professor

Department of radio-diagnosis

M.S. Ramaiah Medical College.

Signature:

Co- guide: DR. GIRIDHAR A.G.

Associate Professor

Department of radio-diagnosis

M.S. Ramaiah Medical College

Signature :

Head of the Department:DR. M.G. SRINATH, MD, DMRD

Sr. Professor & HOD

Department of radio-diagnosis

M.S. Ramaiah Medical College

Signature:

Remarks of:

Chairman & Principal

Signature: