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Received May 17, 2024, accepted June 25 2024, date of publication July 10 2024.

Comparative Performance of Low-Cost Portable Scanner in 
Pregnancy Profile Ultrasonography: A Promising Adjunct to 
Telemedicine

By Afroza Naznin1,2, Muhammad Abdul Kadir1, Fatima Begum3, Khondkar Siddique-e Rabbani1

1 Department of Biomedical Physics and Technology, University of Dhaka, Dhaka 1000, Bangladesh

2 Institute of Nuclear Medicine & Allied Sciences, Sir Salimullah Medical College & Mitford Hospital, Bangladesh Atomic Energy Commission, 
Dhaka, Bangladesh

3 National Institute of Nuclear Medicine & Allied Sciences, Bangladesh Atomic Energy Commission, Dhaka, Bangladesh

ABSTRACT

Background and Objective: Ultrasound scanners are widely used in various clinical settings, but conventional devices are too 
expensive to deploy in every healthcare facility in low-resource countries. Alternative, less costly instruments with comparable 
efficacy are required to ensure this diagnostic service is available in even remotest areas. This study evaluated the effectiveness 
of a commercially available low-cost portable ultrasound machine, particularly focusing on pregnancy profiling. 
Material and Methods: A total of 77 pregnant females were scanned for basic obstetric parameters with two devices, first the 
low-cost scanner, and then a conventional ultrasound machine, considering the latter as the gold standard. The key obstetric 
parameters observed were the number of fetuses, the presence of cardiac pulsation and fetal movement, fetal biometry including 
Crown Rump Length (CRL), Bi-Parietal Diameter (BPD), and Femoral Length (FL), gestational age, placental location, amniotic 
fluid volume, and presentation of the fetus.
Results: The portable device performed well compared with the standard machine in observing the fetal number, presenta-
tion, movement, heartbeat, placental location, and amniotic fluid volume. The correlation coefficients (r²) for measuring BPD, 
FL, CRL, and gestational age using the portable and standard devices were 0.9578, 0.9415, 0.8230, and 0.983, respectively. The 
mean absolute error (MAE) in the measurement of BPD, FL, CRL, and gestational age were 2.24 mm, 2.14 mm, 6.5 mm, and 0.94 
weeks, respectively. 
Conclusion: The results demonstrated the potential of low-cost portable ultrasound devices in pregnancy profile scanning. 
Further studies with larger sample sizes are needed to explore their full potential. With appropriate data transfer arrangements, 
these devices have significant potential for integration into telemedicine services. 

Keywords – Portable ultrasound, Antenatal care, Pregnancy profiling, Maternal health, Telemedicine.

Copyright © 2024. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY): Creative Commons - Attribu-
tion 4.0 International - CC BY 4.0. The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) 
are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is 
permitted which does not comply with these terms.

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27 J Global Clinical Engineering Vol.6 Issue 3: 2024

Naznin, Kadir, Begum, Rabbani: Comparative Performance of Low-Cost Portable Scanner in Pregnancy Profile Ultrasonography: A 
Promising Adjunct to Telemedicine

INTRODUCTION

Ultrasonography (USG) is a non-invasive clinical imag-
ing modality that has gained widespread acceptance as 
a reliable diagnostic tool. It requires less infrastructure 
and logistic support than instruments used for X-ray 
examinations, computed tomography, or magnetic reso-
nance imaging, but it provides real-time information. This 
technology has found its way into various clinical settings, 
including gynecology and obstetrics. The acceptability 
of USG is more profound in this specialty due to a lower 
radiation hazard. Pregnant women are recommended to 
have at least one USG scan during the antenatal period to 
estimate gestational age, and improve detection of fetal 
anomalies and multiple pregnancies.1 

Maternal mortality rate is variable in different parts of 
the world reflecting inequalities in economic conditions 
and quality healthcare access. In 2020, around 95% of 
all maternal deaths occurred in low and lower-middle-
income countries, which was 430 per 100,000 live births.2 

However, the sustainable development goal target is to 
reduce maternal mortality to less than 70 per 100,000 live 
births by 2030. Most of these deaths are due to preventable 
causes, so early detection of complications is crucial to 
ensure prompt clinical intervention, which can be lifesav-
ing. Pregnancy complications also have long-term effects 
on maternal health.3 Therefore, implementing USG in 
remote healthcare facilities for expecting mothers should 
be urgently considered. However, USG devices are costly 
and not readily accessible to rural populations, especially 
in low-income countries.4 

Currently, tablet- or smartphone-based portable USG 
scanners are available at relatively low prices.5 Portable 
USG allows healthcare providers to conduct real-time 
ultrasound examinations remotely. Through telemedicine 
platforms, clinicians can guide on-site healthcare work-
ers or patients to perform ultrasound scans, providing 
valuable insights. Portable ultrasound devices are par-
ticularly valuable in low-resource settings, such as rural 
areas or underserved communities, where access to 
advanced medical facilities is limited. Telemedicine can 
bridge the gap by connecting local healthcare providers 
with specialists who can remotely interpret ultrasound 
images. In obstetrics, portable USG in telemedicine can 

support prenatal care. Expectant mothers can undergo 
ultrasound scans locally, with the results transmitted to 
specialists for analysis. This approach ensures that preg-
nant women in remote areas receive timely and expert 
guidance throughout their pregnancy. Therefore, imple-
menting USG in remote healthcare facilities for expecting 
mothers should be urgently considered. 

However, USG devices are very expensive and not 
readily accessible to rural populations in low-income 
countries.4 Currently, tablet- or smartphone-based portable 
USG scanners are available at relatively lower prices.5 
However, the utility of such low-cost portable scanners in 
pregnancy profiling must be investigated before deploy-
ment in any healthcare program.6 Heuvel et al. conducted 
a comparative analysis assessing the efficacy of low-cost 
ultrasound devices for estimating gestational age (GA) 
in resource-limited settings, suggesting the feasibility 
of utilizing such devices for GA estimation.7 Stock et al. 
compared the performance of pocket-sized ultrasound 
device with a premium machine in bedside examinations 
and reported limited utility.8 Bruns et al. explored the suit-
ability of pocket ultrasound as a supplementary tool for 
clinical assessment specifically during the first trimester 
of pregnancy.9 Kodaira et al. conducted a study to evaluate 
the reliability of ultrasound findings acquired through 
hand-held devices in urgent obstetric scenarios, reporting 
good agreement (κ > 0.8) particularly concerning fetal 
number, presentation, and heartbeat.10 In another study 
focusing on routine antenatal third-trimester ultrasonog-
raphy, researchers found substantial concordance between 
a pocket-sized USG machine and high-specification USG 
units regarding fetal presentation and development.11 

This study involved the scanning of 51 patients, conclud-
ing that portable devices are accurate tools for assessing 
various parameters, including fetal number, presentation, 
placental site, amniotic fluid volume, and the presence of 
key structures during the third trimester of pregnancy. 
However, prior studies primarily examined specific 
trimesters or focused on a limited number of obstetric 
parameters. Thus, the present study aims to investigate 
a comprehensive range of obstetric parameters across all 
three trimesters of pregnancy.



Naznin, Kadir, Begum, Rabbani: Comparative Performance of Low-Cost Portable Scanner in Pregnancy Profile Ultrasonography: A 
Promising Adjunct to Telemedicine

J Global Clinical Engineering Vol.6 Issue 3: 2024  28

MATERIALS AND METHODS 

Study design

This was a cross-sectional study conducted from June 
2022 to December 2022. A total of 77 subjects were randomly 
selected from female patients who came to the hospital 
for pregnancy profiling with more than eight weeks of 
gestation according to their menstrual history. Pregnant 
patients with any emergency or life-threatening condition 
such as pervaginal bleeding, eclampsia, pre-eclampsia, 
premature rupture of membrane, severe abdominal 
pain, etc., or those who were in any stage of active labor 
were excluded. For a significance level of 0.05, a power of 
80%, and a disagreement probability of 0.5, the sample 
size required to detect a Cohen’s kappa value of 0.90 is 
73.12 The disagreement rate of 0.5 was chosen because 
it represents the midpoint where the sample size is the 
highest. Therefore, this study’s sample size of 77 subjects 
can be considered statistically significant. The number 
of subjects in the first, second, and third trimesters of 
pregnancy was 3, 15, and 59, respectively. This study 
did not consider pregnancy cases earlier than 8 weeks 
to avoid potential hazards from ultrasound energy. This 
exclusion criterion explains the lower number of cases 
in the first trimester.

Ethical statement

This study was conducted under the principles embodied 
This study was conducted under the principles embodied 
in the Declaration of Helsinki and in accordance with local 
statutory requirements. Necessary ethical approval was 
obtained from the National Research Ethics Committee, 
Bangladesh (No: 45713122021) for this study. Informed 
consents were obtained from all participants. 

Data collection

After receiving informed consent, each patient was 
scanned twice: first, with a low-cost tablet PC-based por-
table and hand-held device, and then with a sophisticated 
and expensive scanner by a sonographer. Adequate time 
interval was given between the two scans to avoid bias. 
The portable USG device (Sunbright P1), which comprises 
a wired probe (frequency 3–5 MHz, depth 24 cm), is 
connected to a smartphone or computer.13 The portable 

device was chosen considering its low cost, commercial 
availability, safety (CE [Conformité Européenne] certified), 
and data transfer ability to PC and smartphones. Data 
from the portable device was tested against a sophisti-
cated and expensive machine (Samsung Medison Accuvix 
A30), conventionally used in hospital settings, which is an 
USG system with a 21.5-inch-wide LED monitor (screen 
resolution 1920 × 1080) and four probes (depth 2–30 
cm).14 The frequency range of the convex probe of the 
conventional device used for this study was 2–6 MHz. 
This sophisticated machine’s output was considered gold 
standard for comparison of the portable scanner men-
tioned above. However, the actual measurements taken 
of any imaged organ depend on the personal choice of 
selected points on the image by the sonologist, so there 
would be errors in the gold standard too. Therefore, this 
has to be kept in mind when comparing the performance 
of the portable device with that of the standard device. 

The key obstetric parameters observed were: 
(i.) Number of fetuses
(ii.) Presence of cardiac pulsation and fetal movement
(iii.) Fetal biometry including CRL, for first-trimester 

pregnancies
(iv.) BPD and FL, beyond the first trimester
(v.) GA
(vi.) Placental location
(vii.) Amniotic fluid volume 
(viii.) Presentation of the fetus

Images captured on the portable device were saved and 
subsequently transferred to a computer to measure these 
obstetric parameters. Information was also recorded in 
a tabulated form. Diameters and lengths were measured 
using electronic calipers. CRL was measured from the 
top of the head (crown) to the bottom of the buttocks 
(rump) of the fetus. BPD was measured from the outer 
edge of the near calvarial wall to the inner edge of the far 
calvarial wall. FL was identified as the measurement of 
longest bright echo within the fetal femur. All measure-
ments were taken three times, and the arithmetic mean 
was recorded for analysis.



29 J Global Clinical Engineering Vol.6 Issue 3: 2024

Naznin, Kadir, Begum, Rabbani: Comparative Performance of Low-Cost Portable Scanner in Pregnancy Profile Ultrasonography: A 
Promising Adjunct to Telemedicine

Analysis and presentation

Firstly, the values of each parameter obtained using 
the portable device were plotted against the correspond-
ing values obtained using the standard device to observe 
whether an overall correlation exists or not. The agreement 
between the two devices regarding categorical variables 
was assessed with Cohen’s kappa value. If the value is 
within 0.61–0.8, it denotes substantial agreement while 
values above 0.8 (maximum possible: 1.00) represent 
almost perfect agreement.15 For continuous variables, 
Bland-Altman plot and paired t-test were applied. Statis-
tical analyses were performed using SPSS software and 
Microsoft Excel. The Bland-Altman diagram is a statistical 
method that offers insight into the pattern and extent of 
any agreement. To draw the diagram, the difference be-
tween a pair is plotted on the vertical axis of the diagram 
against the mean of the pair on the horizontal axis. The 
upper and lower limits of the interval shows the limits 
of agreement; then it is decided subjectively whether 
the agreement between pairs of readings is acceptable.16 

To evaluate the performance of the portable device, 
mean absolute error (MAE) was also calculated using 
equation (1). 

Here, Xport is the obstetric parameter measured by the 
portable device, Xconv is the corresponding parameter 
measured by the conventional (standard) device and n 
is the number of subjects.

RESULTS 

The total number of pregnant females was 77, aged 18 
to 35 years with a mean age of (25.8 ± 4.27) years. The 
obstetric parameters we have focused on in this study are 
the number and presentation of fetus, presence of car-
diac pulsation and fetal movement, fetal biometry (CRL, 
BPD and FL), estimation of GA, placental location, and 
amniotic fluid volume. Figures 1 to 5 present a selection 
of ultrasound images obtained using both conventional 
and portable devices, providing a representative overview 
of the typical study results. Notably, the images captured 
by the low-cost portable device exhibit lower resolution, 

resulting in inferior image quality and a lack of detail in 
smaller tissue areas.

FIGURE 1. Figure 1. Ultrasound scan images of a first trimester 
fetal pole for Crown Rump Length (CRL) measurement taken with 
the standard device (left) and with the portable device (right)..

FIGURE 2. Figure 2. Ultrasound images of two second-trimester 
fetal heads captured using standard device (A, C) and portable 
device (B, D).

FIGURE 3. Ultrasound images of a third-trimester fetal head 
for Bi-Parietal Diameter (BPD) measurement captured with 
standard device (left) and portable device (right).

(1)



Naznin, Kadir, Begum, Rabbani: Comparative Performance of Low-Cost Portable Scanner in Pregnancy Profile Ultrasonography: A 
Promising Adjunct to Telemedicine

J Global Clinical Engineering Vol.6 Issue 3: 2024  30

Figure 1 illustrates images of a first-trimester fetal pole 
intended for CRL measurement. The image on the left, 
taken with the standard device, demonstrates a clearer 
and more defined fetal pole compared to the image on 
the right, captured by the portable device. The fetal out-
line appears less distinct in the portable device’s image, 
highlighting the difference in image clarity between the 
two scanners. 

Figure 2 presents ultrasound scan images of two 
second-trimester fetal heads captured using both devices. 
Specifically, Figure 2A and Figure 2C display images 
obtained from the conventional device, while Figure 2B 
and Figure 2D depict the corresponding scans acquired 
with the low-cost portable device. The cross marks in the 
images indicate specific points identified by the sonolo-
gist for precise measurements along the marked dotted 
lines. Moving on to Figure 3, ultrasound scan images of 
a third-trimester fetal head for BPD measurement are 
showcased. The image on the right is obtained from the 
portable device, while the left image is captured using 
the conventional unit. Although not precisely identical, 
the image quality and details are considerably similar 
between the two.

In Figure 4, ultrasound scan images of a second-trimester 
fetal femur are presented, with the left image taken using 
the standard device and the right image with the portable 
device. Figure 5 displays ultrasound images of a placenta, 
with the left image captured by the standard device and the 
right image obtained using the portable device. Notably, 
the echogenic layer adjacent to the anterior wall in the 
right-hand image exhibits a reverberation artifact, which 
is exaggerated compared to the left-hand image. 

Correlation of measured values

Figure 6 shows a scatter plot for BPD with the values 
obtained using the portable device plotted against that 
obtained using the standard device. The linear correla-
tion is very high with a squared correlation coefficient 
(r2) of 0.9578. The slope is about 0.98, which is close to 
1, meaning that the two values are almost identical. 

In order to compare the two sets of values in more 
detail, a Bland-Altman plot is shown in Figure 7. For 
these plots, the values obtained using the conventional 
device (the gold standard here) were subtracted from the 
corresponding ones obtained using the portable device 
for each subject and plotted along the vertical axis. The 
means of the BPD values for each subject obtained using 
both the devices were plotted along the horizontal axis. It 
shows that the portable device tended to underestimate 
BPD in earlier pregnancies, while the deviations became 
less as the fetal size increased. Overall the mean value of 

FIGURE 4. Ultrasound images of a second-trimester fetal femur 
recorded with standard device (left) and portable device (right).

FIGURE 5. Ultrasound images of a placenta, with the left image 
captured by the standard device and the right image obtained 
using the portable device.

FIGURE 6. Scatter plot showing correlation between BPD 
measurements taken with two devices.



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Naznin, Kadir, Begum, Rabbani: Comparative Performance of Low-Cost Portable Scanner in Pregnancy Profile Ultrasonography: A 
Promising Adjunct to Telemedicine

BPD given by the portable device was 1.6 mm greater than 
those obtained using the conventional device. The plot 
also shows that 95% of the portable device measurements 
remained within +8 mm and −5 mm range of the actual 
values. The MAE for measuring BPD using the portable 
device was 2.24 mm.

Figure 8 shows the correlation (r2=0.9415) between 
FL measurements taken with two devices. There was no 
tendency towards under or overestimation in relation to 
GA, and 95% of the measurements fell within the range 
+6.2 mm to −7.2 mm, the mean being at −0.5 mm (Figure 
9). The MAE in measuring FL was 2.14 mm.

The portable machine produced wide variations for 
CRL measurements, about 9 to 17 mm from actual values 
(Figure 10). The correlation between the two devices in 
measuring CRL is relatively low (r2=0.823) as shown in 
Figure 11. The MAE in measuring CRL was found to be 
6.5 mm.

In case of GA estimation, out of 77 pregnancies, three 
were in the first trimester i.e., below 12 weeks, 15 in the 
second trimester (12–26 weeks) and 59 cases were in the 
third trimester (beyond 26 weeks), as determined by the 
conventional USG machine. Figure 12 shows the correla-
tion (r2=0.983) between FL measurements taken with two 

FIGURE 7. The Bland-Altman plot shows the difference of the 
two paired BPD measurements plotted against the mean of the 
two measurements.

FIGURE 8. Scatter plot showing correlation between FL meas-
urements taken with two devices.

FIGURE 9. The Bland-Altman plot shows the difference of the 
two paired FL measurements plotted against the mean of the 
two measurements.

FIGURE 10. Scatter plot showing correlation between CRL 
measurements taken with two devices.



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J Global Clinical Engineering Vol.6 Issue 3: 2024  32

devices. Bland-Altman plot in Figure 13 showed 95% of 
the values taken with the portable scanner to be within 
almost two two-week range of the actual values. The MAE 
in measuring GA was 0.93 weeks. It was also noted that 
GA was mostly underestimated by the low-cost device 
in first and second-trimester pregnancies, up to around 
32 weeks of gestation; whether towards term pregnan-
cies, it was more overestimated. Again, the percentage of 
deviation of the GA measured using the portable device 
decreased as the GA increased.

Other parameters 

This study had five qualitative variables: presentation, 
the fetus’s movement and heartbeat, placental location 
and amniotic fluid volume. Majority of the fetus was 
in cephalic presentation (80.5%), followed by floating 
condition (15.6%) and breech (3.9%). Fetal movement 
was present in about 94.8% of the cases, with 3.9% being 
too early to comment and one case where movement was 
absent. We found 76 live pregnancies with regular cardiac 
pulsation and one case of intra-uterine death. Regarding 
placental location, in most cases, it was found in anterior 
uterine wall (53.2%), followed by posterior wall (29.9%). 
Fundal, anterofundal and posteriofundal locations were 
less common. In about 93.5% cases amniotic fluid volume 
was adequate, with 3.9% cases of oligohydramnios, and 
1.3% cases of polyhydramnios. The portable machine’s 
findings agreed with the standard device (Table 1). Chi 
square test also showed significant result (P value < 0.001). 

Single or Multiple pregnancies

By scanning with the conventional USG machine, which 
was considered as the gold standard, 72 cases were found 
to have single pregnancy, while 4 cases had twin pregnancy 
and one case had a triplet. The portable device could detect 
a number of fetus accurately in all these cases.

FIGURE 11. The Bland-Altman plot showing wide variations 
in CRL measurements from the two devices.  

FIGURE 12. Scatter plot showing correlation between gesta-
tional age measurements taken with two devices.

FIGURE 13. The Bland-Altman plot where the difference of the 
two paired gestational age measurements is plotted against the 
mean of the two measurements.



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Naznin, Kadir, Begum, Rabbani: Comparative Performance of Low-Cost Portable Scanner in Pregnancy Profile Ultrasonography: A 
Promising Adjunct to Telemedicine

DISCUSSION

Portable USG scanner, by virtue of its affordability and 
mobility, is being contemplated for use in different low-
resource settings like refugee camps, remote villages, etc. 
besides general practice.17–19 This study compared the 
performance of a low-cost portable ultrasound scanning 
device to a more expensive standard device, particularly 
for obstetric parameters. Very good agreement between 
the two devices in measuring most of the parameters 
was observed in this study, which are number and pre-
sentation of fetus, presence of cardiac pulsation and fetal 
movement, fetal biometry (CRL, Bi-Parietal Diameter, FL), 
estimation of GA, placental location, and amniotic fluid 
volume. However, CRL had more deviation as this was 
measured in the first trimester when the fetus was small, 
and marking out points with the low-cost portable device 
was challenging because of lower resolution. However, as 
the fetus increased, the errors in all parameters decreased 
and were within tolerable limits for acceptance.

GA was determined by measuring fetal biometry; CRL 
in first-trimester pregnancies, and BPD, FL in second and 
third trimesters. Sac diameter is another measure for 
GA determination in earliest pregnancies, but it was not 
used as this study only enrolled pregnant females with 
more than eight weeks of gestation.20 Regarding CRL 
estimation, first-trimester fetal poles are very small, and 
it might be difficult for a low-resolution probe to outline 
the full length separately from yolk sac and inner wall of 
sac (see Figure 1). However, a positive linear correlation 
was observed between CRL values of both devices with 

r2 higher than 0.8 (see Figure 10). The relationship with 
fetal size could be appreciated in the Bland-Altman plot, 
which shows that despite the variable discrepancy, devia-
tion from reference value decreased as CRL approached 
55 mm and higher (see Figure 11). Very few first trimester 
cases were included in this study, which was inadequate to 
reach any definite consensus regarding the efficacy of CRL 
measurement. A Norwegian study focused exclusively on 
hand-held trans-abdominal ultrasound’s ability to evalu-
ate first-trimester viable intra-uterine pregnancy.21 They 
investigated 100 women, comparing hand-held device 
findings to that of high-end trans-vaginal USG. According 
to their observation, viability could be confirmed with 
79% positive and 100% negative predictive value from 
7th week of gestation, and CRL measurements were com-
parable with a median difference of 1 mm. Of course, the 
error also depends on the image’s resolution quality, and 
values obtained using one low-cost device may not apply 
to another device obtained from another manufacturer.

This study observed strong positive linear correlation 
between BPD, FL and GA measurements taken with both 
devices, r2 being greater than 0.9 in all three cases (see 
Figures 6, 8, and 12). In a detailed assessment, the low-
cost device usually underestimated BPD measurements 
in earlier pregnancies, up to about 58 mm, corresponding 
to nearly 24 weeks of gestation (see Figure 7). For the 
next 14–15 mm (up to around 30 weeks) portable device 
values were very close to standard ones, and after that 
deviation increased but uniformly. Figure 2 shows scan 
images of two fetal heads in second trimester. Both near 
and far calvarial walls are well outlined in the images from 
conventional machine, but in the portable device scans 
walls appear blurred, leading to incorrect estimation of 
BPD. This is because the hand-held scanner cannot cap-
ture relatively fast-moving fetuses of earlier pregnancies 
as accurately as the conventional machine. Accordingly, 
image quality improves when fetal size increases and the 
fetus is less mobile ( see Figure 3).

In case of FL measurement by the low-cost instru-
ment, there was no notable tendency towards over or 
underestimation (see Figure 9). Deviation from standard 
was minimal between a range of approximately 30–50 
mm (corresponding GA about 19–26 weeks), and beyond 
second trimester there was uniform increase.

TABLE 1. Kappa Values for Qualitative Variables Showing Good 
Agreement between Two Devices

Parameter κ statistic P value Interpretation

Fetal presentation 1.0 < 0.001 Perfect agreement

Fetal movement 1.0 < 0.001 Perfect agreement

Fetal heartbeat 1.0 < 0.001 Perfect agreement

Placental location 0.892 < 0.001 Very good 
agreement

Amniotic fluid 
volume 0.884 < 0.001 Very good 

agreement



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J Global Clinical Engineering Vol.6 Issue 3: 2024  34

Most of the portable scanner calculations of GA are 
within two two-week range of actual values (see Figure 
13). The Bland-Altman plot shows that the difference 
mostly lies between one week ranges for about up to 30 
weeks of gestation, and then increases gradually. It is high-
est between 35 and 40 weeks. This might be considered 
clinically acceptable because, for GA measurement by USG, 
it has been studied and found that parameters like BPD 
and FL are less accurate during last weeks of pregnancy. 
According to Macgregor et al. the accuracy of gestational 
sac measurement as a predictor of GA is approximately 
±1 week. In case of CRL, the accuracy is within ±5 to 7 
days. During 12–26 weeks, GA determination by BPD and 
FL measurements falls within a range of 10–11 days and 
10–20 days respectively, for 95% of the cases. After 26 
weeks, this range extends to 2–3 weeks.22

Fetal number, movement, presentation and cardiac 
pulsation were accurately detected by the portable device 
in all of the cases, which denotes the perfect efficacy of 
this instrument for assessing those parameters in more 
than eight weeks of gestation (see Table 1). An eight-week 
embryo reaches considerable development by completing 
organogenesis, therefore these parameters were all dis-
cernible despite low resolution. Earlier pregnancies were 
beyond the scope of this study to avoid potential hazard 
by ultrasound energy.19 Kodaira et al. performed a study 
to assess the reliability of ultrasound findings acquired 
with hand-held apparatuses in urgent obstetric settings. 
They reported high agreement (κ > 0.8) in the case of 
fetal number, presentation and heartbeat.10 Their overall 
diagnostic accuracy was still lower than ours, probably 
because they included emergency obstetric patients of 
any GA in a high volume low-resource setting, and scans 
were obtained by medical students with limited training.

Placenta is identified in ultrasound examination as a 
mostly uniform echogenic structure along uterine wall.23 
In our study, anteriorly placed placenta was the com-
monest location, followed by posterior; in accordance 
with a large population based cohort study in Sweden 
involving more than 74 thousand pregnant females.24 
A few fundal placentas were identified as anterior in 
location by the low-cost device, due to exaggeration of 
reverberation artifact along the anterior wall (see Figure 
5). The same phenomenon might have contributed to the 

underestimation of amniotic fluid volume in one case of 
polyhydramnios. However, despite these few exceptions, 
the portable device showed very good agreement with the 
conventional machine regarding both placental localiza-
tion and amniotic fluid estimation (see Table 1). 

LIMITATIONS

The study was conducted with a relatively small sample 
size, as a result there was not enough patients from each 
trimester. First-trimester subjects were especially scarce, 
as we could not enroll females with less than eight weeks 
of gestation. Besides, only stable pregnant women were 
enlisted for study, limiting the number and varieties of 
pathology that could be observed. Therefore, efficacy of 
the portable device in emergency conditions could not be 
evaluated. Further study with larger sample size must be 
done to explore its full potential.

CONCLUSIONS

The portable device used in this study showed remark-
able efficacy in observing several obstetric parameters, 
namely fetal number, presentation, movement, heartbeat, 
placental location and amniotic fluid volume. Regarding 
other variables, the low-cost scanner measurements were 
closest to gold standard during 24–30 weeks for BPD and 
19–26 weeks for FL. GA determination remains within one 
week range from the standard reference during second 
trimester and first six weeks of third trimester. Observing 
the above-mentioned efficiency, such portable device may 
be recommended to provide diagnostic service in remote 
areas, including refugee camps, hilly areas, and islands. 
There is significant potential for integrating low-cost and 
portable ultrasound scanning devices into telemedicine 
service systems with appropriate data transfer arrange-
ments. However, further studies are needed to investigate 
interpersonal variability in the use of portable devices, 
ensuring consistency and accuracy across different users 
and settings.

CONFLICT OF INTEREST

The authors declare no conflict of interest. 



35 J Global Clinical Engineering Vol.6 Issue 3: 2024

Naznin, Kadir, Begum, Rabbani: Comparative Performance of Low-Cost Portable Scanner in Pregnancy Profile Ultrasonography: A 
Promising Adjunct to Telemedicine

GRANT SUPPORT

The International Science Programme (ISP), Uppsala 
University, Sweden, is acknowledged for financial support 
as research grant.

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