3D & 4D Ultrasound Explained: Benefits for Pregnancy and Beyond

A standard 2D ultrasound gives you a flat, cross-sectional slice of the body. 3D ultrasound works differently — it captures a whole volume of tissue, which specialised software then reconstructs with depth and detail. 4D takes this a step further, updating the same 3D imaging continuously so that movement can be seen in real time, almost like a live video.

The difference isn’t simply that a baby’s face looks more like a face. The real clinical value is that 3D and 4D unlock an entirely new plane of view — called the C-plane — which 2D ultrasound simply cannot produce.

General advantages

• Simplified 3D acquisition
• Reduced study time, decreasing patient waiting times
• Faster examination procedure
• The C-plane obtained, which is not possible in 2D
• Complete examination through increased perspective from volume data — better qualitative and quantitative information to diagnose effectively
• All planes of view reproducible: the virtual patient
• Anatomical views not possible with 2D scanning
• Simplified orientation for the referring physician and the patient

Obstetrics

• Morphology, malformation, agenesis (3D, easier in 4D)
• Bone shape abnormalities: spina bifida, dwarfism, club feet on one image, cleft palate versus cleft lip
• Skeletal dysplasia, and abnormalities in dynamic (4D): investigation of the spine
• Fetal heart (4D): better correlation between valves, chambers and vessels; volume calculation of heart cavities; atrial and ventricular communication; assessment of valvular function
• Variety of fetal volume evaluation: urinary bladder, stomach, cyst
• Fetal biopsy (4D): umbilical blood sampling puncture with precision, amniocentesis, kidney dilatation, uropathy
• Fetal wellbeing (4D): normal versus abnormal fetal gestures; evaluation of fetal sleep versus waking; motion — deglutition, respiratory motion, eyelid, limbs and mouth motion, fetal digestive peristaltic motion
• Fetal neuro-myopathy genetic diseases (4D): fetal reactivity and tonicity
• Cord insertion using power Doppler and 3D
• Frontal bones: spatial view of fusion or otherwise

STIC and fetal cardiology

• Fast, efficient assessment
• Information acquired can be accessed offline, allowing processing of reproducible views
• Simultaneous visualisation of 2–3 planes, making it easier for the obstetrician to learn the spatial orientation of the fetal heart
• Better correlation between valves, chambers and vessels
• Volume calculation of heart cavities
• Better access: left and right ventricular outflow tracts are easier to see with the 3D volume; the opening and closing of the foramen ovale is difficult to see in 2D, and new views are now possible with 3D
• Atrial and ventricular communication: the ventricular wall can be seen in relation to the chambers, or the top of the atria cut away to look down into the ventricles using the Magicut tool. Heart walls can be cut away and the septum analysed alone in rotation
• 90-degree crossing in DORV: 3D rotation shows how the VSD relates to the pulmonary artery

Together these allow fetal heart defects to be diagnosed in utero, and pathological conditions to be prepared for treatment at birth.

Gynaecology

* Exact measurement of endometrial thickness and volume (3D/4D) — a thickened endometrium still needs a biopsy to diagnose hyperplasia

• Equivalent hysterosonography realisation (3D/4D)
• Virtual hysteroscopy (3D/4D), using the slicing technique
• Exact volume measurement of cysts (post-menopausal), polyps, myoma or fibroma
• Exact localisation and measurement of ovarian and endometrial tumours
• Gynaecological tumour monitoring after treatment (chemotherapy): effectiveness
• Contrast media to check tumour vascularisation and blood supply
• Gynaecological contrast media for tumour follow-up (4D)
• Contrast media to better evaluate the fallopian tubes — tubal permeability, sterility
• 3D placental abnormalities (placenta praevia)
• 3D placenta: exact insertion versus inferior segment
• IUD and exact positioning

Breast and small parts

• Accurate 4D biopsy in all three planes, with exact placement of the needle
• Breast tumour volume evaluation
• Breast tumour treatment monitoring (chemotherapy)
• Skin tumour infiltration evaluation
• Contrast media use on breast tumours (4D)
• Three planes to define margins — microlobulation, papillomas — with extra information seen in the B and C planes that would otherwise be missed in 2D (the A plane)
• C-plane to view compression versus retraction patterns of tumours

Urology

• Accurate 4D biopsy
• Needle visualisation in all three planes, allowing exact seed implantation (brachytherapy)
• Evaluation of the prostate parenchyma, through the addition of the coronal plane
• Accurate prostate and urinary bladder volume measurement, and of prostatic and bladder tumours (adenofibroma, neoplasm, papilloma)
• Correct positioning of the urinary catheter
• Exact assessment of the post-micturition residue

Internal medicine

• Precise evaluation of acute abdominal syndrome (3D, C-plane): appendix torsion, ileum sigmoidal fistula, Crohn’s disease, endometriosis, recto-sigmoidal fistula, rectitis, proctitis
• Accurate 4D biopsy (liver, kidney)
• Appendicitis with aberrant location — the tip of the finger-like projection in the pelvic area or in meso-colic positioning (3D, C-plane)
• Excellent evaluation of parenchyma and tumour volumes
• Assessment of the bowel wall in selected cases; colorectal polyps are detected by colonoscopy or CT colonography
• Excellent lithiasis localisation in the ureter during renal colic (3D, C-plane)
• Contrast media use in abdominal tumours (kidney, liver)
• 3D reconstruction of bowel segments in selected cases (not a replacement for colonoscopy or CT colonography)
• Excellent 3D evaluation of cholecystitis: wall thickness evaluation, and lithiasis better seen in 3D than in 2D
• Abdominal tumour volume follow-up and monitoring in 3D
• Tumour location versus vascularisation before chemo-embolism (3D/4D)
• Obstruction determination in the icterus mechanism (3D/4D)

For parents: what to expect from your scan

If you would like clear 3D pictures of your baby’s face, the best time is roughly 26 to 30 weeks; these pictures are taken as part of a medical scan, because international ultrasound societies advise against scans done only for souvenir images. Earlier and there is less fat under the skin to give the features definition; later and the head is often deep in the pelvis with less fluid in front of the face.

The picture depends on things nobody controls: the baby’s position, the amount of fluid in front of the face, where the placenta sits, and the amount of maternal tissue the sound must travel through. If the baby is facing your spine, sometimes the answer is genuinely to come back another day. A poor 3D picture and a completely normal pregnancy go together often.

Ultrasound uses sound waves rather than ionising radiation and has been used in pregnancy for decades without evidence of harm when performed by trained operators for medical reasons.

If you have questions about 3D or 4D ultrasound, or would like to schedule a scan, the team at Dr. Layyous clinic is happy to guide you through what to expect and how the imaging can support your care.