Journal of Health Research and Reviews (in Developing Countries)

REVIEW ARTICLE
Year
: 2015  |  Volume : 2  |  Issue : 1  |  Page : 1--6

Review of limb volume measurement techniques in assessing fetal weight by ultrasound with special reference to ImageJ package


Sukriti Malaviya, Shripad Hebbar, Lavanya Rai 
 Department of Obstetrics and Gynaecology, Kasturba Medical College, Manipal University, Udupi, Karnataka, India

Correspondence Address:
Dr. Shripad Hebbar
Kasturba Medical College, Manipal University, Madhavanagar, Manipal - 576 104, District Udupi, Karnataka
India

Abstract

Traditionally intrauterine nutritional status of the growing fetus is evaluated using ultrasound estimated weight, which is then compared with standardized prenatal growth chart for that particular gestational age. The fetuses belonging to less than 10 th centile groups are considered to have reduced growth, whereas those who are more than 90 th centile belong to macrosomia group. Both these extreme groups have their own characteristic obstetric problems and may have poorer outcome. The conventional fetal weight formulae incorporated in regular ultrasound machines are largely dependent on head size, abdominal circumference, and femur length and are prone to random errors as high as 15% of actual birth weight. The margin of error further increases with very small and very large fetuses, and also, these measurements are not valid when the fetus has anterior abdominal wall defects. Malnourishment and obesity studies in pediatric subjects have shown us that subcutaneous fat significantly contributes to actual weight, and mid arm circumference can be used as screening tool for nutritional disorders. The errors in fetal weight estimation can be minimized if fetal soft tissues such as arm and thigh volumes are included for nutritional assessment of the fetus. The recent advances in three-dimensional (3D) ultrasonography has made limb volume estimation simple, easy, and birth weight models using limb volume measurements have higher accuracy, least systematic and random errors compared with the usual two-dimensional biometry of head, trunk, and limb length alone. However, these machines incur significant cost and procurement may not be feasible for resource poor organizations. The present review discusses developments in 3D analysis of fetal limb volulmetry, the methodologies, and affordable solutions using alternative image processing tools such as ImageJ in regular sonographic practice. We have also searched various databases (PUBMED, MEDLINE, SCOPUS, GOOGLE SCHOLAR AND SCIENCE DIRECT, J-Gate Plus and ProQuest) for birth weight models using limb volume measurements and have provided 13 different birth weight equations based on arm and/or thigh volumes.



How to cite this article:
Malaviya S, Hebbar S, Rai L. Review of limb volume measurement techniques in assessing fetal weight by ultrasound with special reference to ImageJ package.J Health Res Rev 2015;2:1-6


How to cite this URL:
Malaviya S, Hebbar S, Rai L. Review of limb volume measurement techniques in assessing fetal weight by ultrasound with special reference to ImageJ package. J Health Res Rev [serial online] 2015 [cited 2024 Mar 29 ];2:1-6
Available from: https://www.jhrr.org/text.asp?2015/2/1/1/158121


Full Text

 INTRODUCTION



Fetal growth is a complex biological process, depending on fetal, placental, and maternal factors. [1] For providers of specialized antenatal care, fetal growth and fetal size assessment are of great interest, as fetal growth aberration is associated with adverse perinatal outcome. [2],[3] Alterations in fetal size outside the normal range are associated with increased morbidity and mortality, not only to the neonate, but also to the mother because of increased operative interference. [4] Poor outcomes can result from perinatal asphyxia in growth-restricted fetuses and shoulder dystocia in macrosomic fetuses. [5],[6] Ultrasound plays a major role in prediction of expected birth weight, but most of the ultrasound machines use inbuilt formulae using conventional two-dimensional (2D) parameters such as biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL) and are widely subjected to errors as great as 15% from actual birth weight (BW). [7] The majority of the formulae tend to overestimate smaller fetuses and underestimate larger fetuses and thereby create confusions while deciding the route of delivery in obstetric practice. [8]

Experience from body weight estimation in pediatric age group suggests that soft tissue assessments, especially subcutaneous limb fat are greatly diminished in malnourished babies. [9] Inclusion of these parameters in fetal weight estimation formulae greatly improves the accuracy and minimizes errors. [10] Soft tissue abnormalities are usually the earliest manifestation of pathological growth and so unless ultrasound measures are sensitive to subtle changes in muscle or fat, such aberrations will be detected late. Quantification of soft tissue parameters helps the obstetrician in differentiating growth-restricted babies from constitutionally small babies. [11] The differences in actual birth weights in two fetuses with the same BPD, HC, AC, and FL parameters may be in fact due to variations in body fat distributions. [12] However, soft tissue characterization is poorly addressed in 2D imaging. [13] Volume measurements by conventional sonography can be technically difficult because of irregularity in subcutaneous fat distribution.

Now three-dimensional (3D) ultrasonography can be used for fetal weight estimation by measurement of the upper-arm and thigh volumes. [14] Various soft tissue markers such as arm and thigh volumes (both total and fractional) have been studied extensively in order to increase the accuracy of fetal birth weight prediction, which has been described in the subsequent paragraphs. To obtain birth weight models involving limb volume (either arm or thigh), we searched various databases mainly PUBMED, MEDLINE, SCOPUS, GOOGLE SCHOLAR AND SCIENCE DIRECT, J-Gate Plus, and ProQuest and we could get 13 articles describing birth weight formulae either using arm volume or thigh volume or both [Table 1].{Table 1}

 LITERATURE REVIEW



Initially ultrasonic birth weight measurements were based on either linear (BPD and FL) or ellipsoid measurements (HC and AC) and more than 27 formulae have been tested using these parameters. [28] There were considerable variations in birth weight prediction and maximum errors were detected in extremes of weight groups.

Jeanty et al. (1985) were the first researchers who thought limb volume measurements can add to the accuracy of fetal weight. [11] They evaluated fetal growth and nutrition using measurements of the subcutaneous tissues of the arm and leg to calculate limb volume. Limb measurements included anteroposterior and transverse diameters including the subcutaneous tissue thickness along with lengths and thickness of long bones (humerus and femur). Circular and elliptical perimeters were used to calculate both arm and thigh and they found that limb volumes were found to be strongly correlated with gestational age and fetal weight. In another study, thigh circumference was used in addition to conventional parameters to increase the power of birth weight prediction; however, using a single cutting plane and circular approximation may limit the usefulness of such studies, especially with large-sized fetuses. [29],[30]

However, 3D technology has revolutionalized the volume measurements in all aspects of ultrasound practice. Virtually any organ can be three-dimensionally assessed using these advanced techniques. Song et al. (2000) have described diagrammatically limb volume measurement method using 3D ultrasound [Figure 1] and have opined that thigh volume measurements using three cross-sectional images of femur is simple and better than -2D ultrasound methods for predicting fetal weight during the third trimester of pregnancy. [17]{Figure 1}

Patipanawat et al. (2006) measured limb volumes using Voluson 530 MT 3D ultrasound machine with a 5.0-MHz transabdominal sector transducer. [31] During neutral position of the fetus, humerus, and femur lengths were visualized in traditional planes. When the whole contour of the humerus or femur diaphysis was visualized, three-dimensional scanning was performed. All image information of the scanned volume of the whole limb was stored in machine's hard disk. Measurements of cross-sectional areas of the limb were made at 5-mm intervals and complete analysis could be completed within 10 and 20 min [Figure 2].{Figure 2}

But both the methods described so far have the technical limitations in the sense that the limb border is not sharp both at the beginning and at the end because of acoustic shadowing caused by the joint and many a times one may not be able to trace the contour because of flexion at hip and knee joint (in case of arm; the elbow joint). Lee et al. (2009) have felt that transverse slices of the mid-limb are more likely to display the sharpest soft tissue borders for manual tracing. [23] They have introduced a new concept, which is known as fractional limb volume. Fractional limb volume is a fetal soft tissue parameter that includes fractional arm volume (AVol) or fractional thigh volume (TVol), and is based on 50% of the long bone diaphysis length [Figure 3]. Such measurements are reproducible among blinded examiners and can be manually calculated from 3D volume datasets within approximately 2 min [Figure 4].{Figure 3}{Figure 4}

Recently a new volumetric technique called Virtual Organ Computer-aided AnaLysis (VOCAL) became available as part of the 3D extended imaging in advanced higher end scan machines. Such technique consists of the delimitation of areas of sequential adjacent planes displayed on the apparatus screen (multislice view), and at the end of the process the equipment sums up the areas, automatically providing the volume as well as the distance between initial and end plane and slices thickness. [32] Cavalcante et al. (2010) have done extensive studies on use of this technique in measurements of fetal limb volume and have opined that the volume measurements done by this procedure is very accurate and has good intra- and interobserver reproducibility. [33] However, the cost of the machine is of concern and may not be affordable for resource-poor settings.

In this review, we explain how the fractional limb volumes can be obtained using softwares that are distributed free under GNU General Public License. The steps of volume measurements are follows:

Volume acquisition in Audio Video Interleave (AVI) formatConversion of AVI to individual framesSelection of frames for area analysisVolume measurement using ImageJ software.

A. Volume acquisition in AVI format

We have used regular ultrasound equipment (Philips HD11XE) for acquisition of volume data set. First the entire length of the femur is visualized in sagittal plane and femur length (FL) is measured [Figure 5] using transabdominal probe. The probe is then turned by 90 degrees and a linear sweep is performed starting from the beginning to end of the femoral diaphysis. The machine automatically records the video (at 18 frames per second) and stores it in AVI format (usually less than 20 mb) in its magnetic disc. The entire procedure takes less than 10 s. This data is then transferred to an optical compact disk using machine's CD drive for offline analysis.{Figure 5}

B. Conversion of AVI to individual frames

We have used Virtualdub v1.10.4 software (can be downloaded from www.virtualdub.org, which is a free package under GNU General Public License) convert video frames of AVI file to individual sequentially named JPEG files. Typically a 5-s video is converted to 90 individual frames. The image sequence that includes starting and end of femoral diaphysis (seen as boomerang shape) are included for further analysis [Figure 6].{Figure 6}

C. Selection of frames for area analysis

The cross-sectional images that represent the true length of femur are considered for further analysis. It can be seen from [Figure 6] that both the beginning and end images do not have sharp borders and have acoustic shadows. Hence the midportion of femur (which constitutes 50% of femoral diaphysial length) is considered for fractional limb volume estimation. However, even this length is represented by 40+ frames and it is tedious to perform cross-sectional area measurement in all these sections. Hence only five representative frames at equal distances are chosen [Figure 7].{Figure 7}

For example, if "n" represents the total number of slices representing the total length of femur, the middle five equidistant cross-sections (x1, x2, x3, x4, x5) are represented by the slice number [a*n] where in [a] takes the value of 0.25, 0.375, 0.50, 0.625, and 0.75 for x1, x2, x3, x4, x5 (rounded to nearest integer). [Figure 8] gives pictorial explanation of mid-limb volume (arm and thigh) and the five cross-sections that are measured for volume calculation.{Figure 8}

D. Volume measurement using ImageJ software

Once the representative images of mid-thigh are chosen as described previously, the next step is to calculate the areas of cross-sections of the thighs in these images. This can be easily accomplished by ImageJ software. ImageJ is a public domain, Java-based image processing program developed at the National Institutes of Health. [34] The software package for various operating systems can be downloaded free of charge from http://imagej.nih.gov/ij/download.html, which includes documentation, help manual, and example images. The software is user-friendly and has the ability to solve many image processing and analysis problems, from -3D live-cell imaging to radiological image processing. [35] At the time of writing this review, pubmed search revealed 850+ indexed articles using search item for the Medical Subject Headings (meSH) word "ImageJ".

Actually the software measures the number of pixels within the given boundary. To convert it into square centimeters one has to set scale, which can be easily accomplished as all ultrasound images have scale bar on the right edge of the picture. The scale can be set for 10 cm for easy visualization [Figure 9] and later on the limb cross-section can be traced manually using free hand trace tool. Once the borders are defined, the software immediately returns the area value. The cross-sectional areas are measured in all five representative images [Figure 10].{Figure 9}{Figure 10}

Once five measurements are obtained, then the fractional thigh volume can be calculated using the formula: Volume (mL) = Avg (A1 + A2 + A3 + A4 + A5) × FL/2 (A = Area, Avg = Average of all areas calculated on five slices).

Actually this formula can be entered into an excel sheet, which automatically calculates the volume. Similarly, fractional arm volume can be calculated using the same guidelines. One can also calculate the entire limb volume as some of the older birth weight formulae still make use of total limb volume. [Table 1] gives details of some of the fetal birth weight estimation models using either total limb volume (or only one volume such as arm volume or thigh volume) or fractional limb volume (either both arm and thigh fractional volume or one of them).

 CONCLUSIONS



The advances in ultrasound techniques have allowed more accurate volumetric analysis of upper and lower limbs for estimation of fetal weight for earlier, accurate, and precise diagnosis of fetal growth aberrations such as intrauterine growth restriction and macrosomia. It may be ideal to do volume related weight estimation using higher end ultrasound machines with 3D/4D imaging modality with built-in volumetric software such as VOCAL system, but these facilities may not be available to all obstetric ultrasound units because of cost constraints. In this article, we have demonstrated that volume-based ultrasound fetal weight estimation is still possible in an existing setup using ImageJ software provided by the National Institutes of Health, USA. We recommend extended use of this gadget in all 3D volumetric analyses using ultrasound.

References

1Grassi AE, Giuliano MA. The neonate with macrosomia. Clin Obstet Gynecol 2000;43:340-8.
2Kramer MS, Olivier M, McLean FH, Willis DM, Usher RH. Impact of intrauterine growth retardation and body proportionality on fetal and neonatal outcome. Pediatrics 1990;86:707-13.
3Kolderup LB, Laros RK Jr, Musci TJ. Incidence of persistent birth injury in macrosomic infants: Association with mode of delivery. Am J Obstet Gynecol 1997;177:37-41.
4Gregory KD, Henry OA, Ramicone E, Chan LS, Platt LD. Maternal and infant complications in high and normal weight infants by method of delivery. Obstet Gynecol 1998;92:507-13.
5Dashe JS, McIntire DD, Lucas MJ, Leveno KJ. Effects of symmetric and asymmetric fetal growth on pregnancy outcomes. Obstet Gynecol 2000;96:321-7.
6Vidarsdottir H, Geirsson RT, Hardardottir H, Valdimarsdottir U, Dagbjartsson A. Obstetric and neonatal risks among extremely macrosomic babies and their mothers. Am J Obstet Gynecol 2011;204:423.e1-6.
7Hadlock FP, Harrist RB, Sharman RS, Deter RL, Park SK. Estimation of fetal weight with the use of head, body, and femur measurements--a prospective study. Am J Obstet Gynecol 1985;151:333-7.
8Deter RL, Harrist RB. Assessment of normal fetal growth. In: Chervenak FA, Isaacson GC, Campbell S, editors. Ultrasound in Obstetrics and Gynecology. Vol. 1. Boston, MA: Little Brown and Co.; 1993. p. 587-95.
9Lapillonne A, Peretti N, Ho PS, Claris O, Salle BL. Aetiology, morphology and body composition of infants born small for gestational age. Acta Paediatr Suppl 1997;423:173-7.
10Araujo E Jr, Vieira MF, Nardozza LM, Filho HA, Pires CR, Moron AF. Three-dimensional ultrasound in the assessment of fetal limb volume. Radiol Bras 2007;40:349-53.
11Catalano PM, Tyzbir ED, Allen SR, McBean JH, McAuliffe TL. Evaluation of fetal growth by estimation of neonatal body composition. Obstet Gynecol 1992;79:46-50.
12Chauhan SP, West DJ, Scardo JA, Boyd JM, Joiner J, Hendrix NW. Antepartum detection of macrosomic fetus: Clinical versus sonographic, including soft-tissue measurements. Obstet Gynecol 2000;95:639-42.
13Schild RL, Fimmers R, Hansmann M. Can 3D volumetric analysis of the fetal upper arm and thigh improve conventional 2D weight estimates? Ultraschall Med 1999;20:31-7.
14Melamed N, Yogev Y, Meizner I, Mashiach R, Bardin R, Ben-Haroush A. Sonographic fetal weight estimation: Which model should be used? J Ultrasound Med 2009;28:617-29.
15Liang RI, Chang FM, Yao BL, Chang CH, Yu CH, Ko HC. Predicting birth weight by fetal upper-arm volume with use of three-dimensional ultrasonography. Am J Obstet Gynecol 1997;177:632-8.
16Schild RL, Fimmers R, Hansmann M. Fetal weight estimation by three-dimensional ultrasound. Ultrasound Obstet Gynecol 2000;16:445-52.
17Song TB, Moore TR, Lee JI, Kim YH, Kim EK. Fetal weight prediction by thigh volume measurement with three-dimensional ultrasonography. Obstet Gynecol 2000;96:157-61.
18Lee W, Deter RL, Ebersole JD, Huang R, Blanckaert K, Romero R. Birth weight prediction by three-dimensional ultrasonography: Fractional limb volume. J Ultrasound Med 2001;20:1283-92.
19Lee W, Balasubramaniam M, Deter RL, McNie B, Powell MD, Goncalves F, et al. Soft tissue parameters improve the precision of fetal weight estimation. Ultrasound Obstet Gynecol 2006;28:389.
20Vieira MF, Nardozza LM, Araujo Júnior E, Guimarães Filho HA, Moron AF. Prediction of birth weight by three-dimensional ultrasonography using fetal upper arm volume: Preliminary results. Rev Bras Ginecol Obstet 2008;30:190-5.
21Schild RL, Maringa M, Siemer J, Meurer B, Hart N, Goecke TW, et al. Weight estimation by three-dimensional ultrasound imaging in the small fetus. Ultrasound Obstet Gynecol 2008;32:168-75.
22Lindell G, Marsál K. Sonographic fetal weight estimation in prolonged pregnancy: Comparative study of two- and three-dimensional methods. Ultrasound Obstet Gynecol 2009;33:295-300.
23Lee W, Balasubramaniam M, Deter RL, Yeo L, Hassan SS, Gotsch F, et al. New fetal weight estimation models using fractional limb volume. Ultrasound Obstet Gynecol 2009;34:556-65.
24Srisantiroj N, Chanprapaph P, Komoltri C. Fractional thigh volume by three-dimensional ultrasonography for birth weight prediction. J Med Assoc Thai 2009;92:1580-5.
25Bennini JR, Marussi EF, Barini R, Faro C, Peralta CF. Birth-weight prediction by two- and three-dimensional ultrasound imaging. Ultrasound Obstet Gynecol 2010;35:426-33.
26Nardozza LM, Vieira MF, Araujo Júnior E, Rolo LC, Moron AF. Prediction of birth weight using fetal thigh and upper-arm volumes by three-dimensional ultrasonography in a Brazilian population. J Matern Fetal Neonatal Med 2010;23:393-8.
27Yang F, Leung KY, Hou YW, Yuan Y, Tang MH. Birth-weight prediction using three-dimensional sonographic fractional thigh volume at term in a Chinese population. Ultrasound Obstet Gynecol 2011;38:425-33.
28Jeanty P, Romero R, Hobbins JC. Fetal limb volume: A new parameter to assess fetal growth and nutrition. J Ultrasound Med 1985;4:273-82.
29Vintzileos AM, Campbell WA, Rodis JF, Bors-Koefoed R, Nochimson DJ. Fetal weight estimation formulas with head, abdominal, femur, and thigh circumference measurements. Am J Obstet Gynecol 1987;157:410-4.
30Hebbar S, Varalaxmi N. Role of fetal thigh circumference in estimation of birth weight by ultrasound. J Obstet Gynecol India 2007;57:316-9.
31Patipanawat S, Komwilaisak R, Ratanasiri T. Correlation of weight estimation in large and small fetuses with three-dimensional ultrasonographic volume measurements of the fetal upper-arm and thigh: A preliminary report. J Med Assoc Thai 2006;89:13-9.
32Guimarães Filho HA, da Costa LL, Araujo Júnior E, Pires CR, Nardozza LM, Mattar R. XI VOCAL (eXtended Imaging VOCAL): A new modality for three-dimensional sonographic volume measurement. Arch Gynecol Obstet 2007;276:95-7.
33Cavalcante RO, Araujo E Jr, Nardozza LM, Rolo LC, Moron AF. Reproducibility of fetal limbs volume by three-dimensional ultrasonography utilizing the XI VOCAL method. Radiol Bras 2010;43:219-23.
34Schneider CA, Rasband WS, Eliceiri KW. NIH Image to ImageJ: 25 years of image analysis. Nat Methods 2012;9:671-5.
35Girish V, Vijayalakshmi A. Affordable image analysis using NIH Image/ImageJ. Indian J Cancer 2004;41:47.