Three-dimensional ultrasound experience in obstetrics

Freehand 3-D Ultrasound Imaging: A Systematic Review

Two-dimensional ultrasound (US) imaging has been successfully used in clinical applications as a low-cost, portable and non-invasive image modality for more than three decades. Recent advances in computer science and technology illustrate the promise of the 3-D US modality as a medical imaging technique that is comparable to other prevalent modalities and that overcomes certain drawbacks of 2-D US. This systematic review covers freehand 3-D US imaging between 1970 and 2017, highlighting the current trends in research fields, the research methods, the main limitations, the leading researchers, standard assessment criteria and clinical applications. Freehand 3-D US systems are more prevalent in the academic environment, whereas in clinical applications and industrial research, most studies have focused on 3-D US transducers and improvement of hardware performance. This topic is still an interesting active area for researchers, and there remain many unsolved problems to be addressed.

Incorporating 3D and 4D Ultrasound into Clinical Practice

3D ultrasound has been slow to make significant impact in clinical practice. In a large part, this is because 2D ultrasound is of such superior quality that sonographers have not seen any gain in adopting the new technology. More recently, however, diverse application of 3D technology has taken place in many branches of medicine, with obstetrics and gynaecology at the forefront. Several manufacturers now produce machines of remarkable sophistication and utility. Hardware and software have been integrated to allow the release of information from the ultrasound examination that has hitherto not been possible. In addition, virtual real time 3D images (4D ultrasound) have captured the imagination of both public and media. We report our preliminary clinical experience with 3 and 4D ultrasound in a limited clinical environment. While not suitable for wide scale application at present, we believe this technology has inherent advantages that will secure its clinical role and that this role will widen rapidly in the near future.

Three-dimensional ultrasound of the fetus: how does it help?

Three-dimensional ultrasonography (3-D US) was introduced to the field of fetal imaging in the early 1990s. Since then several publications have described potential applications for the diagnosis of congenital malformations as well as organ volumetry. This article reviews basic principles of 3-D US as well as its clinical applicability to prenatal diagnosis of abnormalities involving the face, spine and skeletal system, as well as potential applications of 3-D US for fetal cardiovascular and neuroimaging. Limitations related to motion artifacts, acoustic shadowing and barriers to clinical implementation of 3-D US in clinical practice are addressed.

Maternal-fetal medicine fellowship 3- and 4-dimensional ultrasound experience: room for improvement

OBJECTIVES

The purpose of this study was to assess maternal-fetal medicine (MFM) fellowship 3- and 4-dimensional (3D/4D) ultrasound experience and training.

METHODS

A 53-item prenatal diagnosis survey was emailed to 458 associate members of the Society for Maternal-Fetal Medicine. Associate members include both MFM fellows and recent graduates who are not yet board certified in MFM.

RESULTS

A total of 148 associate members completed the survey (32% response rate); 92% were at least in their second year of a fellowship, and 48.1% had completed a fellowship. About half (50.8%) were capable of performing 3D/4D ultrasound examinations ("performers"), whereas 49.2% were not ("nonperformers"). Among performers, about 80% were capable of only basic image acquisition. Overall, 39.5% of respondents received no official 3D/4D ultrasound training, and 55.5% stated that fewer than 1 in 5 of their MFM faculty routinely performed 3D/4D ultrasound examinations. Compared with performers, nonperformers had less formal 3D/4D ultrasound training (53% versus 26%; P = .018) and fewer MFM faculty who performed 3D/4D ultrasound examinations (43% versus 68%; P = .005), and fewer nonperformers were taught by ultrasound mentors (25% versus 47.8%; P = .011).

CONCLUSIONS

Most fellows are not trained in 3D/4D ultrasound. Greater emphasis on ultrasound mentorship and formalized ultrasound training by MFM faculty during fellowships is needed.

Three-dimensional ultrasound and maternal bonding, a third trimester study and a review

OBJECTIVE

To compare the effect of third trimester three-dimensional and four-dimensional (3D/4D) versus two-dimensional (2D) ultrasound (US) of the fetal face on maternal bonding. Studies quantifying the psychological effect of 3D/4D US on mothers, pregnant of a fetus with no detectable abnormalities, were reviewed.

METHODS

One hundred sixty Caucasian women attended a third trimester 3D/4D or 2D US examination. Women filled out the Maternal Antenatal Attachment Scale (MAAS) 1 to 2 weeks before (MAAS1) and 1 to 2 weeks after (MAAS2) the US examination. Visibility, recognition and attractiveness were assessed.

RESULTS

Within both US groups, the MAAS2 scores were significantly higher than the MAAS1 scores (p < 0.0001). No differences in MAAS scores between the US groups emerged. Visibility and recognition were significantly positively related with the increase in MAAS scores (p = 0.003 and p = 0.042) in the 3D/4D group. Of 13 psychological studies, eight studies evaluated bonding and found no difference between 3D/4D and 2D US. The effect of 3D/4D US on satisfaction or perception showed conflicting results, and on anxiety/stress, reduction was the same as after 2D US.

CONCLUSIONS

Bonding increases after either a 3D/4D or 2D US. The effect of 3D/4D US on bonding is stronger at better degrees of visibility and recognition.

Maternal-Fetal Bonding: Ultrasound Imaging's Role in enhancing This Important Relationship

New technology in ultrasound imaging is allowing women to view more visually precise images of their fetuses than ever before. Maternal-fetal bonding describes the attachment interaction that forms between a mother and her unborn child. Ultrasound diagnosis modalities including two-dimensional (2D), three-dimensional (3D) and four-dimensional (4D) may create differences in the amount of maternal-fetal bonding, depending on the modality used. When relevant literature was reviewed on this topic, no significant difference between maternal-fetal bonding was found when comparing 2D vs 3D vs 4D ultrasound. However, certain measures such as a perceived feeling of closeness to the baby were higher with 3D and 4D ultrasounds as compared with 2D ultrasound. Further exploration is needed to ascertain whether different ultrasound modalities have an effect on maternal-fetal bonding in multigestational pregnancies, pregnancies in which there is fetal demise, and to overall examine the effects of using ultrasound for nonmedical ‘entertainment’ purposes by prospective mothers.

How to cite this article

Atluru A, Appleton K, Kupesic Plavsic S. Maternal-Fetal Bonding: Ultrasound Imaging's Role in enhancing This Important Relationship. Donald School J Ultrasound Obstet Gynecol 2012;6(4):408-411.

Pelvic floor imaging

Pelvic floor ultrasound is a valuable adjunct in elucidation of cause, diagnosis, and treatment of pelvic floor disorders. Three-dimensional ultrasound specifically has been shown to have many advantages over conventional imaging modalities. Proper evaluation of pelvic floor muscle function, strength, and integrity is an important component of diagnosis and treatment of pelvic floor disorders. The pelvic floor muscle training used to change the structural support and strength of muscle contraction requires clinicians to be able to conduct high-quality measurements of pelvic floor muscle function and strength. Ultrasound is a useful modality to assess the pelvic floor and its function. As practitioners become more familiar with the advantages and capabilities of ultrasound, this tool should become part of routine clinical practice in evaluation and management of pelvic floor disorders.

Efficacy of assessment in fetal behaviour by four dimensional ultrasonography

This study was conducted to examine the behaviour and facial expressions of the fetus after birth by 4-dimensional (4-D) ultrasonography, and the association of the biophysical profile (BPP) with the Doppler scale. A total of 40 singleton pregnancies were included. All 4-D ultrasonographies were performed using the Accuvix XQ (Medison Co. Ltd, Seoul, Republic of Korea). The BPP and Doppler were performed on gravidas using 2-D ultrasonography. We recorded the newborn while awake no later than 48 h after delivery. The most frequent movement in fetuses and newborn was yawning and isolated arm movements, respectively. Sucking, swallowing (r = 0.78) and isolated limb movements (r = 0.72) in fetuses as observed by 4-D ultrasonography had a relationship with isolated limb movements in the newborn. Because of the limitation of ultrasonography, an overall comparison could not be made. There was a high correlation between sucking, swallowing, and isolated limb movements in fetuses and newborn.

Three-dimensional ultrasound imaging

This review is about the development of three-dimensional (3D) ultrasonic medical imaging, how it works, and where its future lies. It assumes knowledge of two-dimensional (2D) ultrasound, which is covered elsewhere in this issue. The three main ways in which 3D ultrasound may be acquired are described: the mechanically swept 3D probe, the 2D transducer array that can acquire intrinsically 3D data, and the freehand 3D ultrasound. This provides an appreciation of the constraints implicit in each of these approaches together with their strengths and weaknesses. Then some of the techniques that are used for processing the 3D data and the way this can lead to information of clinical value are discussed. A table is provided to show the range of clinical applications reported in the literature. Finally, the discussion relating to the technology and its clinical applications to explain why 3D ultrasound has been relatively slow to be adopted in routine clinics is drawn together and the issues that will govern its development in the future explored.

Three-dimensional ultrasound in prenatal diagnosis

PURPOSE OF REVIEW

Several technological advances have greatly improved three-dimensional sonography, which have improved acquisition and display capabilities. This review describes these technical changes as well as current applications of 3D sonography in prenatal diagnosis.

RECENT FINDINGS

Recently published papers have emphasized the potential of getting a precise 'any plane of choice' from a three-dimensional volume, as a new way of scanning, based on the off-line analysis of a volume dataset. Surface mode has been used to demonstrate malformations and genetic diseases. The maximum rendering mode, which highlights bones, has great potential for imaging the nasal bones and the frontal bones with the metopic suture. Organ volume can be measured, but the utility of this in clinical practice remains to be determined. Three-dimensional ultrasound needs to be standardized.

SUMMARY

Three-dimensional ultrasonography is the most rapidly developing technique in fetal imaging. New features will permit the transition from the era of 'sonography in two-dimensional planes' to 'volume ultrasound'.

THE APPLICATION OF MICROARRAY BASED COMPARATIVE GENOMIC HYBRIDIZATION IN PRENATAL DIAGNOSIS

Microscopic forms of karyotyping and cytogenetic analysis by means of G-banded chromosome analysis and rapid FISH (fluorescencein situhybridization) on amniotic fluids or chorionic villus samples are at present regarded as the gold standard for prenatal diagnosis of chromosomal anomalies. Nevertheless, up to now the resolution of conventional chromosomal analysis was limited to approximately 4–5 Mb and not smaller than 2 Mb for FISH. Thus numerous common microdeletion syndromes are not detectable by conventional karyotyping. In addition, prenatal cells yield lower band resolution by conventional karyotyping than peripheral white blood cells making detection of subtle abnormalities even more difficult. With the advances in molecular-based techniques, a collaborative effort has led to the standardized method for detection of a restricted set of common chromosomal aneuploidies and microdeletion syndromes such as Down's syndrome, DiGeorge or Angelman syndrome either by rapid FISH and/or quantitative fluorescent PCR (QF-PCR). Even if the presence of particular phenotypic features of microdeletion or duplication syndromes may direct the use of syndrome-specific FISH tests in the postnatal period, syndrome-specific FISH analysis still has a very limited potential and application in the prenatal period due to the limitation in prenatal morphological or imaging diagnosis of many of the syndromes.

Embryonic staging using a 3D virtual reality system

BACKGROUND

The aim of this study was to demonstrate that Carnegie Stages could be assigned to embryos visualized with a 3D virtual reality system.

METHODS

We analysed 48 3D ultrasound scans of 19 IVF/ICSI pregnancies at 7-10 weeks' gestation. These datasets were visualized as 3D 'holograms' in the BARCO I-Space virtual reality system. Embryos were staged according to external morphological features (i.e. mainly limb development). After staging, the crown rump length (CRL) was measured. Stage and CRL were compared with gestational age based on the date of oocyte retrieval and with the classical data on embryology from the Carnegie Collection.

RESULTS

Embryonic staging was relatively easy because the I-Space allows depth perception, which helps in the estimation of size and position. The presumed stages corresponded well with the measured CRL. However, in 28 out of 48 cases, the stages seemed to have been reached earlier than previously described for the Carnegie Collection.

CONCLUSIONS

The I-Space, tentatively named Virtual Embryoscopy, is a promising non-invasive tool for early pregnancy evaluation. Combining embryonic growth with embryonic development opens a new area to study the relationship between embryonic growth, development and morphology, as well as second and third trimester pregnancy complications.

Two- versus three-dimensional ultrasound in the second and third trimester of pregnancy: impact on recognition and maternal-fetal bonding. A prospective pilot study

OBJECTIVE

To assess the impact of three-dimensional (3D) versus two-dimensional (2D) ultrasound (US) on maternal-fetal bonding.

STUDY DESIGN

Prospective randomized pilot study among low risk women with singleton fetuses in the second and third trimester. Dependent on the randomization pattern, US was commenced either with 2D US or 3D US and the effects were recorded with standardized questionnaires.

RESULTS

Sixty patients were included. Although the quality of 2D US, assessed by the examinator, was superior to 3D US, maternal recognition was higher with 3-D US (P = 0.004). With 2D US, nulliparous patients had significantly more difficulties visualizing the fetus, than multiparous (P = 0.03). However, the maternal preference of 3D US had no significant impact on maternal-fetal bonding.

CONCLUSION

Ultrasound had no significant effect on maternal-fetal bonding. Three-dimensional images may facilitate recognition of the fetus, but 3D US did not have higher impact on maternal-fetal bonding. This finding may be a reason not to consider 3D ultrasound for routine scanning.

How useful is 3D and 4D ultrasound in perinatal medicine?

AIM

The purpose of this paper is to review and analyze the published literature on the use of three-dimensional (3DUS) and four-dimensional (4DUS) ultrasound in perinatal medicine.

METHODS

We systematically searched Medline through PubMED (January 2000-January 2006), including EMBASE/Excerpta Medica database as well as the Cochrane Database of Systematic Reviews. The search terms used to identify clinical application of 3DUS and 4DUS studies in perinatal medicine were technical development, special features, and recommendation for fetal imaging, research on 3DUS or 4DUS, and the usage of invasive 3DUS or 4DUS procedures. The reference bibliographies of relevant books were also manually searched for supplementary citations. Inclusion criteria were as follows: (1) studies related to the use of 3DUS or 4DUS in perinatal medicine; (2) full text were available in English; (3) publication format of original scientific articles, case reports, editorials or literature reviews and chapters in the books.

RESULTS

Five hundred and seventy-five articles were identified, and among those, 438 were relevant to this review.

CONCLUSIONS

3DUS and 4DUS provided additional information for the diagnosis of facial anomalies, evaluation of neural tube defects, and skeletal malformations. Additional research is needed to determine the clinical utility of 3DUS and 4DUS for the diagnosis of congenital heart disease, central nervous system (CNS) anomalies and detection of fetal neurodevelopmental impairment assessed by abnormal behavior in high-risk fetuses.

Parental artistic drawings of the fetus before and after 3-/4-dimensional ultrasonography

OBJECTIVE

The purpose of this study was to assess the impact of 3-/4-dimensional ultrasonography (3D/4DUS) on parental impressions of their fetus using preexamination and postexamination parental drawings.

METHODS

One hundred one parents (32 male and 69 female) were asked to draw pictures of their fetus immediately before and after undergoing 3D/4DUS. A drawing assessment instrument was used to evaluate the fetal anatomy by 4 reviewers. Overall descriptive quality and a comparison of before and after images were assessed.

RESULTS

Reviewers judged the drawings as significantly different in 23% to 56% of cases, slightly different in 41% to 64%, and having no significant difference in 2% to 22%; some difference was identified in at least 78%. Reviewers familiar with ultrasonography were able to correctly predict which picture was drawn first in 78%. Differences identified were related to extremity positioning, personalized uterine environment, and artistic nature. No significant difference in the overall total scoring for anatomic differentiation before and after 3D/4DUS was found. A trend in drawing less anatomic structures after 3D/4DUS was discovered. Significantly fewer people drew hair after 3D/4DUS (P<.01) even when they had drawn hair before the 3D/4DUS. Similar significant differences were seen for the lower extremities (P<.01), with less detail being presented after the 3D/4DUS.

CONCLUSIONS

Differences were seen between drawings made before and after 3D/4DUS by parents. Drawings after 3D/4DUS emphasized structures seen during the 3D/4DUS examination and were more reality based, whereas drawings before 3D/4DUS were more iconographic and based on preconceived anatomic knowledge.

A comparison between acoustic output indices in 2D and 3D/4D ultrasound in obstetrics

OBJECTIVE

Three-dimensional (3D) ultrasound is gaining popularity in prenatal diagnosis. While there are no studies regarding the safety of 3D ultrasound, it is now widely performed in non-medical facilities, for non-diagnostic purposes. The present study was aimed at comparing the acoustic output, as expressed by thermal index (TI) and mechanical index (MI), of conventional two-dimensional (2D) and 3D/4D ultrasound during pregnancy.

METHODS

A prospective, observational study was conducted, using three different commercially available machines (iU22, Philips Medical Systems; Prosound Alfa-10, Aloka; and Voluson 730 Expert, General Electric). Patients undergoing additional 3D/4D ultrasound examinations were recruited from those scheduled for fetal anatomy and follow-up exams. Fetuses with anomalies were excluded from the analysis. Data were collected regarding duration of the exam, and each MI and TI during 2D and 3D/4D ultrasound exams.

RESULTS

A total of 40 ultrasound examinations were evaluated. Mean gestational age was 31.1 +/- 5.8 weeks, and mean duration of the exam was 20.1 +/- 9.9 min. Mean TIs during the 3D (0.27 +/- 0.1) and 4D examinations (0.24 +/- 0.1) were comparable with the TI during B-mode scanning (0.28 +/- 0.1, P = 0.343). The MIs during the 3D volume acquisitions were significantly lower than those in the 2D B-mode ultrasound studies (0.89 +/- 0.2 vs. 1.12 +/- 0.1, P = 0.018). The 3D volume acquisitions added 2.0 +/- 1.8 min of actual ultrasound scanning time (i.e. not including data processing and manipulation, or 3D displays, which are all post-processing steps). The 4D added 2.2 +/- 1.2 min.

CONCLUSIONS

Acoustic exposure levels during 3D/4D ultrasound examination, as expressed by TI, are comparable with those of 2D B-mode ultrasound. However, it is very difficult to evaluate the additional scanning time needed to choose an adequate scanning plane and to acquire a diagnostic 3D volume.

Prenatal evaluation of facial clefts by three-dimensional extended imaging

OBJECTIVES

To determine the prenatal diagnostic accuracy of two-dimensional ultrasound (2DUS) alone versus 2DUS in conjunction with three-dimensional ultrasonography (3DUS) including orthogonal display (OGD) and three-dimensional extended Imaging for cleft lip and primary palate.

MATERIALS AND METHOD

Fetuses being suspected of having a facial cleft by previous ultrasound examination or family history were examined sequentially with 2DUS and then 3DUS.

RESULTS

Of a total of 30 infants, 22 had cleft lip and nine also had cleft palate at birth. The use of 2DUS with or without 3DUS correctly identified all cases of cleft lips prenatally. However, the use of 2DUS in conjunction with 3DUS correctly identified more cleft primary palate than 2DUS alone (88.9% vs 22.2%, P < 0.01). Cleft primary palate was well demonstrated in both the multi-slice view (MSV) and OGD modes. In one case, a cleft palate was shown in the MSV mode but not in the Oblique view (OBV) mode. All the unaffected fetuses were reported as no cleft palate with the use of MSV mode.

CONCLUSIONS

Combined approach of 2DUS and 3DUS with both OGD and MSV modes significantly improved the prenatal detection rate for a cleft palate compared with 2DUS alone (88.9% vs 22.2%) without decreasing the specificity.

Goitrous congenital hypothyroidism in a twin pregnancy causing respiratory obstruction at birth: implications for management

We report a twin pregnancy complicated by fetal goitrous hypothyroidism secondary to dyshormonogenesis caused by thyroglobulin deficiency. Antenatal treatment with intra-amniotic thyroxine was considered but not performed, given the late gestational age at diagnosis and the multiple nature of the pregnancy. Both twins developed airway obstruction at delivery, requiring intubation and ventilation. We review the literature and describe the practical issues relating to the antenatal assessment and perinatal management of fetal goitre.

Preexamination and postexamination assessment of parental-fetal bonding in patients undergoing 3-/4-dimensional obstetric ultrasonography

OBJECTIVE

The purpose of this study was to determine whether there is a change in parental bonding and couples' attitudes toward their fetus after undergoing 3-/4-dimensional ultrasonography (3D/4DUS).

METHODS

Sixty-five fathers and 124 mothers were asked to fill out a maternal-fetal attachment questionnaire relating to how they felt about their fetus before and after 3D/4DUS and to mark on a line indicating their feelings about the ultrasonography experience. In addition, 135 parents filled out a positive feelings questionnaire consisting of 5 sections assessing their feelings about the fetus. The 3D/4DUS examination included rendering of the fetal face, limbs, and thorax.

RESULTS

One hundred forty-two patients filled out all questions and were analyzed for the total attachment score. The difference of the total score for the maternal-fetal attachment questionnaire before and after 3D/4DUS had a z value of 5.6 for all patients and was statistically significant (P < .0001). In analyzing each question, 5 were found to have a statistically significantly different score for women, but only 2 were found so for men. The scores for the line, before and after 3D/4DUS, showed a significant difference for men but not women. The women studied did not show a change using this instrument because their median response was at the maximum measurement before their sonograms. The positive feelings questionnaire showed a statistically significant change for women in all sections but for men in only 2.

CONCLUSIONS

Parents have a change in attitude regarding their fetus after undergoing 3D/4DUS. Mothers showed an increase in bonding to their fetus after 3D/4DUS in more categories than fathers.

The effects on maternal anxiety of two-dimensional versus two- plus three-/four-dimensional ultrasound in pregnancies at risk of fetal abnormalities: A randomized study

OBJECTIVE

To test the hypothesis that the use of two-dimensional (2D) ultrasonography with three-dimensional/four-dimensional (3D/4D) ultrasonography can reduce anxiety to a greater extent in women at risk of having a fetus with congenital abnormalities than the use of 2D ultrasonography alone.

METHODS

A total of 124 women attending the prenatal diagnostic clinic of a teaching hospital were randomized into the intervention group (2D ultrasonography followed by 3D/4D ultrasonography) or control group (2D ultrasonography alone). The primary outcome was maternal anxiety levels, which were assessed by the Spielberger state-trait anxiety inventory. We measured the anxiety levels in all women at the first visit, at around 18 weeks' gestation (immediately after ultrasound examinations) and at 28 weeks' gestation.

RESULTS

A short-term reduction of the state-anxiety score (by around 2 points) from the first visit to after ultrasound examinations was observed in both the intervention group and the control group. Unexpectedly, a small increase in the state-anxiety score from the first visit to 28 weeks' gestation was observed in the intervention group but not in the control group, though there was no significant difference in the changes between the two groups. Repeated measures ANOVA (analysis of variance) also showed that there was no significant interaction effect between groups and time of assessment on the state-anxiety scores (F = 1.072 and P = 0.344). About 80% of women reported a better understanding that their baby was normal after viewing 3D rather than 2D images.

CONCLUSION

This randomized study indicates that the addition of 3D/4D ultrasound does not cause a significant reduction in maternal anxiety in pregnancies at risk of fetal abnormalities compared with conventional 2D ultrasound alone.

Rendering in fetal cardiac scanning: the intracardiac septa and the coronal atrioventricular valve planes

OBJECTIVE

In this study we aimed to apply spatio-temporal image correlation (STIC) rendering to visualize the virtual planes of the interventricular and interatrial septa (IVS, IAS) as well as the atrioventricular (AV) annuli plane just distal to the semilunar valves (coronal atrioventricular (CAV) plane) in normal and pathological fetal hearts, to ascertain whether these planes add to fetal cardiac examination.

METHODS

Unselected gravidae presenting for anatomy scan or patients referred for fetal echocardiography in the second and third trimesters of pregnancy with suspected or diagnosed cardiac malformation were scanned using the five planes technique with the STIC modality to obtain cardiac volume sets for each patient. Rendering capabilities were employed to obtain the 'virtual planes' to evaluate the IVS, IAS, AV annuli, and size and alignment of the great vessels.

RESULTS

A total of 136 normal scans were performed to establish a learning curve for STIC acquisition and post-processing rendering and analysis. An additional 35 cases with cardiac anomalies were accrued. In 131/136 (96.3%) normal scans the IAS and IVS were visualized successfully, while in 127/136 (93.4%) normal fetuses the CAV plane was successfully visualized. In 13 anomalous cases the IVS plane improved ventricular septal defect (VSD) evaluation, and in four the IAS plane contributed to foramen ovale evaluation. The modality improved visualization of the septa and the assessment of the defects, as well as the foramen ovale flap and pattern of movement of the foramen ovale. In five cases the CAV plane improved evaluation of the alignment of the major vessels in relation to the AV annuli, and in three the evaluation of the semilunar valves, with or without malalignment of the great vessels.

CONCLUSIONS

Rendering STIC technology allows the visualization of virtual planes (IAS, IVS, AV annuli-CAV plane), which can clarify our understanding of anatomical defects and may improve communication with the management team and family.

Applications of 2-dimensional matrix array for 3- and 4-dimensional examination of the fetus: a pictorial essay

OBJECTIVES

Two-dimensional (2D) matrix array is a new technology for the performance of 3-dimensional and 4-dimensional (4D) ultrasonography. In this study, we report the use of a 2D matrix array transducer for examination of fetal structures including the fetal heart.

METHODS

Thirty-four fetuses without abnormalities and 19 fetuses with congenital anomalies were examined with a 2D matrix array transducer (x3-1, IE-33; Philips Medical Systems, Bothell, WA). Median gestational age was 25 6/7 weeks (range, 13 0/7-40 1/7 weeks).

RESULTS

(1) A 360 degrees rotation and examination of selected structures was possible in the second trimester. (2) Structures were examined by maintaining the transducer in a fixed position and rotating the volume using the system trackball. (3) Dorsal and ventral parts of the hands and feet were visualized in a single volume data set, in real time, without moving the transducer. (4) Real-time en face visualization of atrioventricular valves was possible from the ventricular or atrial chambers. (5) Four-dimensional images of bones were obtained by decreasing gain settings only, with no need for cropping. (6) Four-dimensional reconstruction of vascular structures was possible with color Doppler imaging. Two limitations were identified: (1) lower resolution than mechanical volumetric transducers, and (2) narrow volume display.

CONCLUSIONS

Real-time direct 4D imaging with 360 degrees rotation for examination of fetal anatomic structures is feasible. This technology allows examination of fetal structures from multiple perspectives, in real time, without the need to move the transducer in the maternal abdomen. Further technological developments may overcome the limitations identified in this study.

Women's responses to ultrasound examinations during routine screens in an obstetric clinic

OBJECTIVE

The primary purpose of this research was to evaluate the impact of prenatal ultrasound consultation on maternal-fetal attachment, knowledge of fetal behavior, and development and reduction of anxiety in pregnant women scheduled for routine ultrasound screens. A standard depression screen was also used to evaluate depression levels of women undergoing these screens in the sonography clinic.

METHODS

To evaluate the impact of an ultrasound consultation, the following were undertaken: (1) a preliminary observational study of routine screens in the sonography clinic was performed; (2) an ultrasound consultation manual was developed and established as reliable; and (3) women undergoing evaluations between 16 and 26 weeks' gestational age were randomly assigned to a standard care group (n = 24; the standard clinical ultrasound screen) or an ultrasound consultation group (n = 28; the ultrasound consultation was done, including the standard screen with extended consultation on fetal development, maternal and familial responses, and maternal-fetal interaction).

RESULTS

The ultrasound consultation group had a significant positive change in maternal-fetal attachment scores, lower state anxiety scores, and more favorable responses to the sonographic examination (P .05). Women's depression scores did not differ between the ultrasound consultation and standard care groups and were similar to maternal prenatal depression levels in other studies.

CONCLUSIONS

Ultrasound consultation was responsible for increasing maternal-fetal attachment and reducing maternal anxiety. It may be an important component of more comprehensive prevention/intervention strategies. The implications for ultrasound consultation in clinical research and practice are discussed.

Three-dimensional ultrasonographic reslicing of the fetal brain to assist prenatal diagnosis of central nervous system anomalies

OBJECTIVES

The purpose of this study was to evaluate the potential of 3-dimensional ultrasonographic planar and nonplanar reslicing techniques.

METHODS

Fetuses with severe brain anomalies diagnosed by means of 2-dimensional ultrasonography were prospectively included in the study. Good-quality 3-dimensional volumes of the fetal head were obtained in each case. Subsequently, these volumes were reviewed with use of 3-dimensional extended imaging with Oblique View and DynamicMR (Medison Co, Ltd, Seoul, Korea).

RESULTS

Eight fetuses (mean gestational age, 23 weeks; range, 20-30 weeks) with the following central nervous system anomalies were examined: semilobar holoprosencephaly, absent cavum septum pellucidum, porencephaly in twin-to-twin transfusion syndrome, partial agenesis of the corpus callosum, Dandy-Walker variant, open-lip schizencephaly, aneurysm of the vein of Galen, and dilated cavum vergae.

CONCLUSIONS

Planar and nonplanar reslicing of the volumes delivered informative images in any reconstructed plane. One important prerequisite, however, was the absence of acoustic shadowing during data acquisition.

The use of needle biopsy for assessment of placental gene expression

OBJECTIVE

The purpose of this study was to test the hypothesis that placental samples that are obtained by needle aspiration ex vivo are useful for the determination of villus gene expression.

STUDY DESIGN

Placental biopsy was performed with a spinal needle after uncomplicated deliveries. Villi were inspected microscopically, and RNA was extracted and analyzed with capillary electrophoresis. Gene expression was determined with quantitative polymerase chain reaction.

RESULTS

We obtained more placental villous fragments per aspiration using a 20-gauge needle (5.2 +/- 1.8 fragments) than with a 22-gauge needle (3.3 +/- 1.6 fragments; P < .01). RNA quality was adequate, based on the 28S and 18S recombinant RNA bands, with a mean 260/280 ratio of 1.88. The amount of extracted RNA correlated with the number of villous fragments per aspirate. Importantly, the expression of NDRG1 and hPL, both markedly altered in hypoxia, was consistent between villi that were obtained by either needle or standard biopsy.

CONCLUSION

Placental samples that are obtained by ex vivo needle aspiration are useful for the extraction of RNA and for the determination of villous gene expression.

Biomedical Imaging Graduate Curricula and Courses: Report from the 2005 Whitaker Biomedical Engineering Educational Summit

We present an overview of graduate programs in biomedical imaging that are currently available in the US. Special attention is given to the emerging technologies of molecular imaging and biophotonics. Discussions from the workshop on Graduate Imaging at the 2005 Whitaker Educational Summit meeting are summarized.

Three- and 4-dimensional ultrasound in obstetric practice: does it help?

OBJECTIVE

The purpose of this article was to review the published literature on 3-dimensional ultrasound (3DUS) and 4-dimensional ultrasound (4DUS) in obstetrics and determine whether 3DUS adds diagnostic information to what is currently provided by 2-dimensional ultrasound (2DUS) and, if so, in what areas.

METHODS

A PubMed search was conducted for articles reporting on the use of 3DUS or 4DUS in obstetrics. Seven-hundred six articles were identified, and among those, 525 were actually related to the subject of this review. Articles describing technical developments, clinical studies, reviews, editorials, and studies on fetal behavior or maternal-fetal bonding were reviewed.

RESULTS

Three-dimensional ultrasound provides additional diagnostic information for the diagnosis of facial anomalies, especially facial clefts. There is also evidence that 3DUS provides additional diagnostic information in neural tube defects and skeletal malformations. Large studies comparing 2DUS and 3DUS for the diagnosis of congenital anomalies have not provided conclusive results. Preliminary evidence suggests that sonographic tomography may decrease the examination time of the obstetric ultrasound examination, with minimal impact on the visualization rates of anatomic structures.

CONCLUSIONS

Three-dimensional ultrasound provides additional diagnostic information for the diagnosis of facial anomalies, evaluation of neural tube defects, and skeletal malformations. Additional research is needed to determine the clinical role of 3DUS and 4DUS for the diagnosis of congenital heart disease and central nervous system anomalies. Future studies should determine whether the information contained in the volume data set, by itself, is sufficient to evaluate fetal biometric measurements and diagnose congenital anomalies.

Three-dimensional and four-dimensional fetal echocardiography: a new frontier

PURPOSE OF REVIEW

One of the difficulties of conventional two-dimensional cardiac imaging is the inability to examine fetal cardiac anatomy from multiple angle planes. Three-dimensional and four-dimensional ultrasound allows the fetal examiner to more accurately accomplish this task. Currently, multiple disciplines may be involved in the examination of the fetal heart (pediatric cardiologists, obstetricians, maternal-fetal medicine specialists, and radiologists). The three-dimensional and four-dimensional imaging equipment used by these specialty physicians varies greatly. The purpose of this communication is to review techniques using three-dimensional and four-dimensional imaging that the pediatric cardiologist may not be exposed to in the clinical environment, however, in consulting with colleagues needs to have an understanding of these imaging modalities.

RECENT FINDINGS

The reconstruction of cardiac structures using this technology allows the examiner to view cardiac anatomy in a manner that was limited by previous two-dimensional imaging. Volume datasets are obtained in the three-dimensional static mode (no cardiac motion) or using four-dimensional - the three-dimensional heart is observed contracting during one or multiple cardiac cycles. Therefore, the fourth dimension is time. Using either three-dimensional or four-dimensional technology datasets are acquired, followed by image reconstruction. The image reconstruction enables the examiner to evaluate a two-dimensional image using multiple views, evaluate intracardiac anatomy at different depth planes, and recreate casts of blood flow of the chambers and great vessels.

SUMMARY

This new technology has enhanced the ability of the examiner to identify normal and complex fetal heart anatomy during the early second to the late third trimesters of pregnancy.

Three-dimensional extended imaging: a new display modality for three-dimensional ultrasound examination

OBJECTIVE

To describe Three-Dimensional eXtended Imaging (3DXI) as a new display modality for three-dimensional (3D) ultrasound examination of the fetus.

METHODS

The spine, palate, heart and brain were evaluated using 3D ultrasound examination at a mean gestational age of 22 weeks in 35, 31, 32 and 31 fetuses, respectively. The volume data captured were analyzed using the conventional orthogonal display mode (ODM), as well as the 3DXI, which includes the Multi-Slice View (MSV) mode and the Oblique View (OBV) mode. The MSV mode allows simultaneous display of multiple sequential parallel planes while the OBV mode allows examination of a non-standard straight or curved plane.

RESULTS

The MSV mode allowed a simultaneous display of multiple sequential parallel planes of the fetal structures, but we found some uncertainty if an isolated image in one of the multi-slice images represented the exact level of a fetal structure. The MSV mode was advantageous in one of the six cases of facial cleft by allowing the simultaneous display of bilateral clefts that were located in two different axial planes. The multi-slice images were helpful in making the diagnosis in one case of holoprosencephaly. The OBV mode allowed examination of the coronal plane across the curvature of the spine, and the 'in-plane' view of the interventricular septum in a non-gated study.

CONCLUSION

The 3DXI can display the volume data in a different manner from that which usually results from the use of more conventional ODM, and provide additional information over conventional two-dimensional sonography.

The potential of four-dimensional (4D) ultrasonography in the assessment of fetal awareness

AIM

The aim of the study was to observe different expressions and movements of a fetal face during investigation of fetal behavior in the second and the third trimester of normal pregnancies, as a probable manifestation of fetal awareness.

SUBJECTS AND METHODS

Over a 6-month period a study was conducted in three centers in Zagreb, Croatia and in Barcelona and Malaga, Spain. Women with singleton pregnancies (16-33 weeks) who were referred for ultrasound check-up for determination of gestational age, suspicious fetal malformations, polyhydramnios, and/or the assessment of biophysical profile or other possible pathology, were assigned to the study. After regular two-dimensional (2D) ultrasound assessment at an antenatal clinic, pregnant women were offered the possibility of undergoing 4D ultrasound examination if the fetus and the mother were considered "normal", i.e., if ultrasound and clinical assessment were uneventful. If the newborn delivered at term had 1- and 5-min Apgar scores of 7 and 10, respectively, and if the newborn was considered "term and normal" (normal spontaneous activity, normal posture and tone, and presence of some primitive reflexes) at the first and subsequent regular check-ups, the inclusion criteria were deemed to have been met. Out of 119 patients, 99 fulfilled the inclusion criteria, 40 of whom were in the second, and 59 in the third trimester of pregnancy. A Voluson 730 Expert system with a transabdominal 5-MHz transducer was used for 4D ultrasonography. After regular 2D scanning, the 4D mode was switched on, and a live 3D image was reconstructed by selecting ideal 2D mid-sagittal images of the face (the region of interest). The volume was automatically scanned every 2 s while the surface-rendered mode was switched on, and 4D images were displayed on the screen and recorded on videotape during a 30-min observation period. Movements of the following fetal face structures were analyzed: forehead, brows, nasal soft tissue and nasolabial folds, upper lip, oral cavity and tongue, lower lip and chin, eyelids and eyes, mouth and mouth angles, and facial expression. 4D ultrasonography allowed in utero observations of fetal facial expressions such as smiling, yawning, and swallowing.

RESULTS

The quality of 4D depiction of fetal facial expressions increased with gestational age. The frequency of fetal facial expressions such as yawning ranged from 1 and 6 with a median of 1.5 per 30-min observation period; smiling ranged from 2 and 8 with the median of 2; tongue expulsion ranged from 2 to 6, median 3; mouth and eye squeezing ranged from 5 to 10, median 6; scowling ranged from 1 to 3, median 0.5; and isolated eye blinking ranged from 4 to 12 with a median of 5.

CONCLUSIONS

Our study shows the ability of 4D sonography to depict different facial expressions and movements, which might represent fetal awareness. Nevertheless, long, precise and thorough observation of fetal faces by 4D sonography was hampered as the images were only near real-time. Thus, we were only able to study the quality and not the quantity of facial movement patterns.

Effects of ultrasound on maternal-fetal bonding: a comparison of two- and three-dimensional imaging

OBJECTIVES

The purpose of this study was to evaluate the effect of two-dimensional (2DUS) compared to three-dimensional ultrasound (3DUS) imaging on the maternal-fetal bonding process.

METHODS

Fifty mothers who had 2DUS and 50 who had 2DUS and 3DUS were included in the study. A postpartum survey by telephone interview was carried out to assess maternal-fetal bonding. Bonding was evaluated by analysis of extent of prenatal image sharing, maternal ability to form a mental picture of the baby and mother's comments about their ultrasound images. Data were analyzed using the independent t-test, Chi-square and Mann-Whitney U-tests.

RESULTS

Mothers who received 3DUS showed their ultrasound images to more people (median, 27.5; interquartile range, 14.5-40.0) than mothers receiving 2DUS alone (median, 11.0; interquartile range, 5.0-25.5) (P < 0.001, Z = -3.539). Eighty-two percent of the subjects screened with 3DUS had a greater tendency to form a mental picture of the baby postexamination compared to 39% of the 2DUS subjects (P < 0.001, Z = -3.614). Mothers receiving a 3DUS study were more likely to receive comments on the similarities/differences of the neonate compared to those having 2DUS studies. Furthermore, 70% of the mothers receiving 3DUS felt they 'knew' the baby immediately after birth vs. 56% of the mothers receiving 2DUS (P = 0.009, Z = -2.613). Both 2DUS and 3DUS experiences were positive, however, the comments made by the mothers undergoing 3DUS (n = 18) were more exclamatory (amazed, wonderful, fabulous) than those undergoing 2DUS (n = 4). Patients having a 3DUS examination consistently scored higher than those having a 2DUS examination alone for all categories of maternal-fetal bonding.

CONCLUSION

3DUS appears to more positively influence the perceptions of mothers to their babies postbirth compared to 2DUS. Specifically, mothers who had 3DUS showed their ultrasound images to a greater number of people compared to mothers who had 2DUS alone and this may represent mother's social support system. 3DUS may have a greater impact on the maternal-fetal bonding process.

Neurobehavioral assessment before birth

The complexities of neurobehavioral assessment of the fetus, which can be neither directly viewed nor manipulated, cannot be understated. Impetus to develop methods for measuring fetal neurobehavioral development has been provided by the recognition that individual differences in neurobehavioral functioning do not originate with birth and acceptance of the key contribution of the antenatal period to postnatal life. Research has centered around four aspects of fetal functioning: heart rate, motor activity, behavioral state, and responsivity to stimulation. Longitudinal studies have revealed that the developmental trajectories of these characteristics parallel the developing nervous system, detected a transitional period between 28 and 32 weeks gestation, and established within-fetal stability during the second half of gestation. Despite the promise of fetal stimulation and habituation paradigms as measures of neural functioning, significant safety and ethical concerns exist. Construction of a unified fetal neurobehavioral scale is premature until a sufficient degree of normative data is available and the predictive validity of specific aspects of fetal neurobehavior to child developmental outcomes is better established.

Role of three-dimensional ultrasound in assessment of women undergoing urethral bulking agent therapy

PURPOSE OF REVIEW

The technique of three-dimensional ultrasound imaging has been developed over the past 15 years, and has been particularly embraced by the field of obstetrics. More recently, advances have been made in gynecological applications, with promise demonstrated in pelvic floor and lower urinary tract imaging. A clinically useful extension of three-dimensional ultrasound imaging of the lower urinary tract is the assessment of urethral bulking agent therapy, as three-dimensional ultrasound imaging provides an objective means of assessing technical outcomes (i.e. periurethral position, configuration and volume of bulking agent). Our aim is to review recent developments in the use of three-dimensional ultrasound imaging in female incontinence, focusing on its role in the assessment of women undergoing urethral bulking agent therapy for stress urinary incontinence.

RECENT FINDINGS

Three-dimensional ultrasound imaging provides reproducible, affordable and clinically relevant information in the assessment of urethral bulking agent therapy with collagen. Serial, long-term three-dimensional ultrasound imaging assessment has enabled a definition of the technical outcome associated with a durable improvement in continence. The optimal volume varies widely between patients, but a circumferential or horseshoe-shaped periurethral configuration of collagen is strongly correlated with a durable improvement in continence. This finding is in agreement with limited data from a two-dimensional ultrasound assessment of Macroplastique.

SUMMARY

Three-dimensional ultrasound imaging provides an objective means of assessing technical outcomes from urethral bulking agent therapy not available previously. The volume and configuration information obtained allows for rational therapeutic decision-making, particularly with regard to determining the need for re-injection and recognizing the failure of an adequate therapeutic trial.

Three-Dimensional Ultrasound in Small Parts

For longer than 40 years, ultrasound (US) has been a widely used imaging tool in medical practice, which has proved helpful for the diagnosis and staging of diseases. Although three-dimensional ultrasound (3D) US has been available for more than 10 years, it was only through the development of the most recent computer technologies and its adaptation to ultrasound systems, that 3D US has become able to achieve the high level of sensitivity and performance necessary to be considered seriously in clinical practice. 3D US is rapidly turning into a technology with an ever-increasing range of applications in numerous fields because, among other reasons, it helps overcome some of the key limitations related to two-dimensional imaging. 3D US can be used in ultrasonography for small parts, among other medical areas. The assessment of the testicle, parotid, thyroid and parathyroid glands is properly achieved. The multiplanar presentation and niche mode are quite useful to determine the extension--inside or outside the organs-, of nodules, cysts or tumors. The volume measurement is better assessed with 3D US and given this, we can perform studies that follow growth in order to decide medical or surgical treatment. The VOCAL makes it possible to obtain a proper after-treatment follow-up of focal disorders in these small organs. Neovascularization is clearly viewed with 3D US and probably can suggest malignant origin of a neoplasm. 3D US offers a more comprehensive image of anatomical structures and pathological conditions and also permits to observe the exact spatial relationships. We are aware more studies are needed to demonstrate specificity and sensibility of 3D US in particular clinical conditions, not only in small parts but also is some other non-Ob/Gyn applications.

Ultrasound imaging of the pelvic floor. Part II: three-dimensional or volume imaging

In this second part of a review of pelvic floor ultrasound imaging, current three-dimensional (3D) ultrasound technology and its use for imaging pelvic floor structure and function is described. Recent technical developments enable rapid automated volume acquisition in real time, and currently available transducers designed for abdominal use are well suited for translabial/transperineal imaging. To date, such systems have been used to image the urethra, the levator ani and paravaginal supports, prolapse and implants used in pelvic floor reconstruction and anti-incontinence surgery. While 3D pelvic floor imaging is a field that is still in its infancy, it is already clear that the method has opened up entirely new opportunities for the observation of functional anatomy.

Something Old and Something New: a Brief History of Thyroid Ultrasound Technology

OBJECTIVE

To discuss both early and recent ultrasound technologic advances and to explore the role of such technology in the evaluation of the thyroid gland.

METHODS

The physics of sound and the history of the use of reflected sound waves are reviewed, and the medical applications of ultrasound, with a particular focus on the thyroid gland, are presented.

RESULTS

Since the first reports of thyroid ultrasonography were published in the late 1960s, the field has undergone remarkable evolution. Ultrasound imaging improved in parallel with growth in computing, transducer, and display technology. The transition from A-mode to B-mode to gray-scale imaging was associated with dramatic improvements in clarity and interpretability of ultrasound images. Current high-resolution ultrasound images are able to identify virtually all structural thyroid lesions of clinical significance. Although ultrasound characteristics cannot be used for accurate diagnosis of benign thyroid lesions, certain features such as irregular margins, microcalcifications, and central vascularity suggest the presence of "suspicious" thyroid nodules. Recent advances including the use of contrast agents, tissue harmonic imaging, and multiplanar reconstruction of images will further enhance the resolution and interpretability of ultrasound images. The use of Doppler flow analysis may improve the predictive value for determining the risk of a malignant thyroid lesion, but no current ultrasound technique is capable of determining benignity with an acceptable degree of accuracy. Ultrasound guidance of fine-needle aspiration biopsy has been demonstrated to improve both diagnostic yield and accuracy and will likely become the standard of care.

CONCLUSION

Because high-quality ultrasound systems are now available at a reasonable price, routine clinical use of ultrasonography is considered an important extension of the physical examination by many endocrinologists.

Recent developments in fetal medicine

Several advances have been made in the field of fetal medicine since the last BMJ review on the subject. This review covers advances in prenatal screening, imaging techniques, management of multiple pregnancies, and fetal therapy

Four-dimensional real-time sonographically guided cauterization of the umbilical cord in a case of twin-twin transfusion syndrome

In the past decade, three-dimensional (3D) sonographic technology has matured from a static imaging modality to near-real-time imaging. One of the more notable improvements in this technology has been the speed with which the imaged volume is acquired and displayed. This has enabled the birth of the near-real-time or four-dimensional (4D) sonographic concept. Using the 4D feature of the current 3D sonography machines allows us to follow moving structures, such as fetal motion, in almost real time. Shortly after the emergence of 3D and 4D technology as a clinical imaging tool, its use in guiding needles into structures was explored by other investigators. We present a case in which we used the 4D feature of our sonographic equipment to follow the course and motion of an instrument inserted into the uterus to occlude the umbilical cord of a fetus in a case of twin-twin transfusion syndrome.