Three-dimensional ultrasonographic imaging of the neonatal brain in high-risk neonates: preliminary study

Quantitative 3-D head ultrasound measurements of ventricle volume to determine thresholds for preterm neonates requiring interventional therapies following posthemorrhagic ventricle dilatation

Dilatation of the cerebral ventricles is a common condition in preterm neonates with intraventricular hemorrhage. This posthemorrhagic ventricle dilatation (PHVD) can lead to lifelong neurological impairment through ischemic injury due to increased intracranial pressure, and without treatment can lead to death. Two-dimensional ultrasound (US) through the fontanelles of the patients is serially acquired to monitor the progression of PHVD. These images are used in conjunction with clinical experience and physical exams to determine when interventional therapies such as needle aspiration of the built up cerebrospinal fluid (ventricle tap, VT) might be indicated for a patient; however, quantitative measurements of the ventricles size are often not performed. We describe the potential utility of the quantitative three-dimensional (3-D) US measurements of ventricle volumes (VVs) in 38 preterm neonates to monitor and manage PHVD. Specifically, we determined 3-D US VV thresholds for patients who received VT in comparison to patients with PHVD who resolve without intervention. In addition, since many patients who have an initial VT will receive subsequent interventions, we determined which PHVD patients will receive additional VT after the initial one has been performed.

Three-dimensional ultrasound of the neonatal brain: technical approach and spectrum of disease

Brain pathology is an important cause of morbidity and mortality in neonates, especially in the premature population. While conventional two-dimensional neurosonography is traditionally used for screening, diagnosis and monitoring of brain disorders such as germinal matrix hemorrhage, periventricular leukomalacia and hydrocephalus, three-dimensional ultrasonography has gained popularity in a variety of clinical applications in recent years. Three-dimensional ultrasonography is not yet widely utilized in pediatric imaging but is a potentially powerful tool for evaluating the neonatal brain. Three-dimensional neurosonography allows imaging of the entire brain in a single volumetric sweep and offers the capability of reconstructing images in the axial plane and performing volumetric analyses that are unavailable in conventional two-dimensional neurosonography. The purpose of this article is two-fold: (1) to present the technical aspects of three-dimensional neurosonography and (2) to illustrate the potential applications of three-dimensional neurosonography in the context of commonly encountered neonatal neuropathology.

In Vivo Validation of a 3-D Ultrasound System for Imaging the Lateral Ventricles of Neonates

Intra-ventricular hemorrhage, with the resultant cerebral ventricle dilation, is a common cause of brain injury in preterm neonates. Clinically, monitoring is performed using 2-D ultrasound (US); however, its clinical utility in dilation is limited because it cannot provide accurate measurements of irregular volumes such as those of the ventricles, and this might delay treatment until the patient's condition deteriorates severely. We have developed a 3-D US system to image the lateral ventricles of neonates within the confines of incubators. We describe an in vivo ventricle volume validation study in two parts: (i) comparisons between ventricle volumes derived from 3-D US and magnetic resonance images obtained within 24 h; and (ii) the difference between 3-D US ventricle volumes before and after clinically necessary interventions (ventricle taps), which remove cerebral spinal fluid. Magnetic resonance imaging ventricle volumes were found to be 13% greater than 3-D US ventricle volumes; however, we observed high correlations (R(2) = 0.99) when comparing the two modalities. Differences in ventricle volume pre- and post-intervention compared with the reported volume of cerebrospinal fluid removed also were highly correlated (R(2) = 0.93); the slope was not found to be statistically significantly different from 1 (p < 0.05), and the y-intercept was not found to be statistically different from 0 (p < 0.05). Comparison between 3-D US images can detect the volume change after neonatal intra-ventricular hemorrhage. This could be used to determine which patients will have progressive ventricle dilation and allow for more timely surgical interventions. However, 3-D US ventricle volumes should not be directly compared with magnetic resonance imaging ventricle volumes.

Time efficiency and diagnostic agreement of 2-D versus 3-D ultrasound acquisition of the neonatal brain

The purpose of this study was to compare acquisition time efficiency and diagnostic agreement of neonatal brain ultrasound (US) scans obtained with a 3-D volume US acquisition protocol and the conventional 2-D acquisition protocol. Ninety-one consecutive premature neonatal brain ultrasound scans were prospectively performed on 59 neonates with the conventional 2-D acquisition protocol. Immediately after the 2-D study, a coronal 3-D ultrasound volume was acquired and later reconstructed into axial and sagittal planes. All 59 neonates were imaged in the neonatal intensive care unit to rule out intracranial hemorrhage. Total time for 2-D and 3-D acquisition protocols was recorded, and a two-tailed t-test was used to determine if study durations differed significantly. One pediatric neuroradiologist reviewed the reformatted 3-D images, tomographic ultrasound images. Results were compared with the clinical interpretation of the 2-D conventional study. The mean scanning time for the 2-D US acquisition protocol was 10.56 min (standard deviation [SD] = 7.11), and that for the 3-D volume US acquisition protocol was 1.48 min (SD = 0.59) (p ≤ 0.001). Inter-observer agreement revealed k values of 0.84 for hydrocephalus, 0.80 for germinal matrix hemorrhage/intraventricular hemorrhage, 0.74 for periventricular leukomalacia and 0.91 for subdural collection, hence near-perfect to substantial agreement between imaging protocols. There was a significant decrease in acquisition time for the 3-D volume ultrasound acquisition protocol compared with the conventional 2-D US protocol (p = <0.001), without compromising the diagnostic quality compared with a conventional 2-D US imaging protocol.

Editorial review: pediatric 3D ultrasound

Three-dimensional ultrasound is an established diagnostic imaging technique in many specialties. However, in neonates, infants and children three-dimensional ultrasound still is underutilized, partially due to time constraints for post-processing and restricted availability, of devices as well as dedicated pediatric transducers. Also reimbursement issues still need to be addressed. This editorial review presents more or less established pediatric three-dimensional ultrasound applications with proven diagnostic benefit as well as potential future applications of three-dimensional/four-dimensional ultrasound in infants and children, aiming at enhancing research and promoting practical use of three-dimensional ultrasound in relevant pediatric conditions. Particularly, applications in neonatal neurosonography, ultrasound of the urogenital tract as well as some other small part and miscellaneous queries are highlighted. Additional other potential and future indications are discussed briefly, also mentioning restrictions and potential future developments. In summary, three-dimensional ultrasound holds some potential to widen sonographic diagnostic capabilities throughout childhood and hopefully will be increasingly investigated and introduced into clinical practice provided respective equipment and pediatric three-dimensional/four-dimensional ultrasound transducers become available.

Usefulness of 3D sonography of the central nervous system in neonates and infants in the assessment of intracranial bleeding and its consequences when examined through the anterior fontanelle

Due to the possibility to examine at the patient bedside or incubator, ultrasound imaging of the central nervous system, particularly through the anterior fontanelle, is the most common diagnostic examination performed in neonates and infants with neurological problems. Despite its common application, this method has certain limitations. These limitations are associated with cross-sections of the cerebral structures that can be obtained when examining through the anterior fontanelle. The aim of the paper was to assess the usefulness of three dimensional sonography of the central nervous system in neonates and infants in the assessment of intracranial bleeding and its consequences when examined through the anterior fontanelle. The study enrolled 283 patients treated at the Pediatric Teaching Hospital at the Medical University of Lublin in whom a transfontanelle cerebral examination was indicated. The two- and three-dimensional ultrasound examinations of the central nervous system were conducted in 283 patients aged from 1 day to 18 months (mean age: 2 months). 254 three-dimensional examinations were of diagnostic value. The number of detected pathological lesions was higher in a statistically significant way (p = 0.007) in the three-dimensional ultrasound examination. In the authors’ own studies, the highest sensitivity and statistically significant superiority of the three-dimensional method over the two-dimensional one referred to detecting intraventricular or intracerebral hemorrhages. Novel techniques of ultrasound imaging, including the three-dimensional one, have undoubtedly increased the diagnostic possibilities of sonography and, at the same time, retained all its advantages.

3D ultrasound system to investigate intraventricular hemorrhage in preterm neonates

Intraventricular hemorrhage (IVH) is a common disorder among preterm neonates that is routinely diagnosed and monitored by 2D cranial ultrasound (US). The cerebral ventricles of patients with IVH often have a period of ventricular dilation (ventriculomegaly). This initial increase in ventricle size can either spontaneously resolve, which often shows clinically as a period of stabilization in ventricle size and eventual decline back towards a more normal size, or progressive ventricular dilation that does not stabilize and which may require interventional therapy to reduce symptoms relating to increased intracranial pressure. To improve the characterization of ventricle dilation, we developed a 3D US imaging system that can be used with a conventional clinical US scanner to image the ventricular system of preterm neonates at risk of ventriculomegaly. A motorized transducer housing was designed specifically for hand-held use inside an incubator using a transducer commonly used for cranial 2D US scans. This system was validated using geometric phantoms, US/MRI compatible ventricle volume phantoms, and patient images to determine 3D reconstruction accuracy and inter- and intra-observer volume estimation variability. 3D US geometric reconstruction was found to be accurate with an error of <0.2%. Measured volumes of a US/MRI compatible ventricle-like phantom were within 5% of gold standard water displacement measurements. Intra-class correlation for the three observers was 0.97, showing very high agreement between observers. The coefficient of variation was between 1.8-6.3% for repeated segmentations of the same patient. The minimum detectable difference was calculated to be 0.63 cm(3) for a single observer. Results from ANOVA for three observers segmenting three patients of IVH grade II did not show any significant differences (p > 0.05) for the measured ventricle volumes between observers. This 3D US system can reliably produce 3D US images of the neonatal ventricular system. There is the potential to use this system to monitor the progression of ventriculomegaly over time in patients with IVH.

Volume US of the urinary tract in pediatric patients-a pilot study

Three-dimensional ultrasonography (3DUS) adds functionality to two-dimensional ultrasonography (2DUS) by allowing examiners to explore volume datasets using multiplanar or rendering methods already familiar to radiologists. In this pilot study, 30 patients referred for ultrasound examination of the urinary tract were examined by 3DUS. Three abnormalities initially not detected by 2DUS were seen: bilateral bladder diverticulae, urachal remnant and bilateral accessory renal arteries. Rendered images of the bladder trigone were feasible in the majority of patients. Potential applications of this technology in pediatric uroradiology and technical pitfalls are illustrated.

Potential role of 3DUS in infants and children

The objective of this review is to discuss basic technical aspects as well as potential pediatric applications of three-dimensional ultrasound (3DUS). Different 3DUS-techniques are already commercially available. Most commonly, a transducer-integrated motor drives a scan-head to acquire a volumetric dataset, which is then reconstructed and viewed using various post-processing techniques. It has been proved feasible to apply 3DUS with pediatric transducers in typical pediatric investigations. Based on our own experiences and on review of the literature, 3DUS can be successfully used in infants and children for brain, spine, cardiac, urinary tract (particularly assessment of hydronephrosis, and virtual cystoscopy), and female genital (e.g., for assessment of uterine malformations) US, and for various other applications, particularly in small parts. Power Doppler data can be integrated, allowing 3DUS-angiography. Thus, 3DUS promises to become a useful adjunct for imaging children, particularly as it enhances ultrasound by offering additional, previously inaccessible planes, rendering options and surface assessments. 3DUS should be increasingly exploited, thus hopefully helping reduce the need for more invasive or burdening (e.g., ionizing radiation) investigations in children.

Sonography of the Neonatal Brain

Neurosonography is a critical part of the care of the sick newborn. Sonography is superior to other modalities in imaging of the brain because it can be performed at the bedside, is easily reproducible, and does not require ionizing radiation or sedation. This article refreshes the sonographer in the normal anatomy and appearance of the neonatal brain using sonography, as well as some of the more common pathologic conditions that may be encountered.

Three-dimensional ultrasonography-based virtual cystoscopy of the pediatric urinary bladder: a preliminary report on feasibility and potential value

OBJECTIVE

The purpose of this study was to validate the feasibility and potential of 3-dimensional ultrasonography (3DUS)-based virtual cystoscopy in the pediatric urinary bladder.

METHODS

Twenty patients (age range, newborn-14 years) underwent urinary tract ultrasonography and 3DUS of the urinary bladder. From this data set, virtual cystoscopy was reconstructed for visualization of the inner bladder surface. Three-dimensional ultrasonography was compared with 2-dimensional ultrasonographic (2DUS) findings, voiding cystourethrography (VCUG) results, and reports from cystoscopy or surgery when available.

RESULTS

Three-dimensional ultrasonography was feasible in all patients. Data quality was sufficient for virtual cystoscopy without major motion artifacts. The 3DUS results matched all other findings; particularly, 3DUS superiorly visualized the ureteral ostium and the bladder neck configuration; in 5 patients, 3DUS depicted pathologically shaped ostia not detected by 2DUS. This correlated with the presence of vesicoureteral reflux on VCUG. Performing virtual cystoscopy added 1 minute to the investigation time (range, 0.5-2 minutes) and 3 minutes for postprocessing and viewing (range, 2-5 minutes).

CONCLUSIONS

Three-dimensional ultrasonography-based virtual cystoscopy is feasible in the pediatric urinary bladder without sedation. It reveals surface information not accessible by 2DUS, improving detection of pathologic conditions such as atypically shaped ureteral ostia. Three-dimensional ultrasonography-based cystoscopy may become a valuable adjunct to 2DUS of the pediatric urinary tract, improving selection criteria for further imaging such as VCUG, and potentially may help reduce the need for endoscopic cystoscopy. However, these preliminary results still have to be confirmed in prospective studies with larger patient numbers.

Continuity between Fetal and Neonatal Neurobehavior

As the development of the brain is unique and continuing process throughout the gestation and after birth, it is expected that there is also continuity of fetal and neonatal movements which are the best functional indicator of developmental processes of the brain. Understanding the relation between fetal and infant behavior and developmental processes of the brain in different periods of gestation may make achievable the distinction between normal and abnormal brain development. Epidemiological studies revealed that many neurologically impaired infants belong to low risk population, which means that they seemed to be developmentally normal as fetuses and as infants, while later childhood neurological disability was diagnosed. Which methods of neurological assessment are available for that purpose? Prenatally we have not many possibilities for neurological assessment, while postnatally the repertoire of diagnostic possibilities is increasing. Among the postnatally available methods for neurological assessment, the most important are: clinical neurological assessment, neuroimaging methods, assessment of general movements (GMs) and combinations. Postnatal neurological assessment is probably easier to perform than prenatal, by using a simple and suitable for everyday work screening clinical test with good reliability, specificity and sensitivity.

There is a possibility for the early and simple neurological assessment of the term and preterm newborns with the aim to detect associated risks and anticipate long-term outcome of the infant, and to establish a possible causative link between pregnancy course and neurodevelopmental outcome. The evaluation of infant's developmental optimality should be assessed in order to investigate whether the infant is neurologically normal or damaged. Neurological assessment at term by Amiel-Tison (ATNAT) is taking into account neurological maturation exploring so called lower subcortical system developing earlier from the reticular formation, vestibular nuclei and tectum, and upper cortical system developing from the corticospinal pathways.

Conventional acquisition neuroimaging techniques together with modern diffusion neuroimaging techniques can identify typical patterns of brain injury, even in the early course of the disease. However, even though highly suggestive, these patterns cannot be considered as pathognomonic. Nevertheless neuroimaging methods alone are not sufficient to predict the neurological outcome in neonates from highrisk population.

Prechtl stated that spontaneous motility, as the expression of spontaneous neural activity, is a marker of brain proper or disturbed function. The observation of unstimulated fetus or infant which is the result of spontaneous behavior without sensory stimulation is the best method to assess its central nervous system capacity. All endogenously generated movement patterns from un-stimulated central nervous system could be observed as early as from the 7-8 weeks of postmenstrual age, with developing a reach repertoire of movements within the next two or three weeks, continuing to be present for 5 to 6 months postnatally. This remarkable fact of the continuity of endogenously generated activity from prenatal to postnatal life is the great opportunity to find out those high-risk fetuses and infants in whom development of neurological impairment is emerging. The most important among those movements are GMs involving the whole body in a variable sequence of arm, leg, neck and trunk movements, with gradual beginning and the end. They wax and wane in intensity, force and speed being fluent and elegant with the impression of complexity and variability. Assessment of GMs in high-risk newborns has significantly higher predictive value for later neurological development than neurological examination. Kurjak and co-workers conducted a study by 4D ultrasound and confirmed earlier findings made by 2D ultrasonography, that there is behavioral pattern continuity from prenatal to postnatal life. Assessment of neonatal behavior is a better method for early detection of cerebral palsy than neurological examination alone.

Are we approaching the era when there will be applicable neurological test for fetus and assessment of neonate will be just the continuation? This is still not easy question to answer, because even postnatally there are several neurological methods of evaluation, while in utero we are dealing with more complicated situation and less mature brain. Could neonatal assessment of neurologically impaired fetuses bring some new insights into their prenatal neurological status is still unclear and to be investigated. New scoring system for prenatal neurological assessment of the fetus proposed by Kurjak et al will give some new possibilities to detect fetuses at high neurological risk, although it is obvious that dynamic and complicated process of functional CNS development is not easy to investigate.

The aim of this review is to present continuity of the functional central nervous system assessment from prenatal to postnatal life.

Modern pediatric ultrasound: potential applications and clinical significance. A review

After the introduction of ultrasound (US), the new imaging modality was first warmly welcomed, but then lost reputation and importance particularly in radiology leading to an increasing number of other -- particularly computed tomography (CT) -- investigations, which especially in pediatrics was a potentially dangerous development considering the radiation hazards. However, innovative and creative US approaches as well as new US techniques such as amplitude-coded color Doppler, harmonic and high-resolution imaging, and US contrast media or three-dimensional US have been introduced over the past decade and significantly broadened the potential of US. Thus, now, the role of US has been widened in many conditions and queries, and US today may well play a more pronounced and essential role in modern imaging algorithms at still relatively low cost, with sufficient diagnostic accuracy and conspicuity. Particularly in the pediatric setting, these new capabilities are applicable in many queries and almost all body regions and should be used to reduce the number of more invasive or radiating and relatively costly examinations that often additionally need some sedation or intravenous iodinated contrast material. To readily provide this approach for sick children, we need to promote the knowledge about modern US capabilities, to train US staff to guarantee 24-h availability of adequate pediatric US performance, and to make it known to the referring clinicians.

Hydronephrotic kidney: pediatric three-dimensional US for relative renal size assessment--initial experience

PURPOSE

To prospectively evaluate accuracy of three-dimensional (3D) ultrasonography (US) for assessment of relative renal size in infants and children with hydronephrosis.

MATERIALS AND METHODS

Informed consent was obtained from parents and also from children who were older than 8 years. Study was approved by ethics committee. Two-dimensional (2D) US, 3D US, and scintigraphy were performed in 40 patients with hydronephrosis (age range, neonate to 16 years; seven girls, 33 boys) without acute renal disease. Twenty patients also underwent magnetic resonance (MR) urography. US and MR urography were performed by one experienced pediatric radiologist; 3D US and MR urographic volume calculations were performed by specifically trained radiologists. Three-dimensional US was performed with integrated 3D volume probes or external system based on electromagnetic positioning devices. At 2D US, kidney volume was calculated with application of ellipsoid equation. At MR urography and 3D US, real renal parenchymal volume was calculated with subtraction of dilated collecting system. Split renal function was assessed with static renal scintigraphy. Three-dimensional US results were graded with respect to image quality and compared with results of 2D US, scintigraphy, and MR urography by using mean difference percentage and standard deviation of the difference. All investigations were performed with blinding. Inter- and intraobserver variability were calculated with coefficient of variation.

RESULTS

In 76 of 80 kidneys, 3D US image of diagnostic quality was obtained. Three-dimensional US volume measurements compared well with MR urographic measurements (mean difference, -2.5% +/- 7.8 [standard deviation] vs 25.8% +/- 32.2 for 2D US) and with scintigraphically assessed split renal function (mean difference, 1.2% +/- 9.2 vs 15.9% +/- 43.8 for 2D US). Intra- and interobserver variability were +/-6.4% and +/-9.9%, respectively.

CONCLUSION

Initial experience with renal 3D US indicates that it is an accurate method for assessment of renal parenchymal volume and relative renal size, provided there is no acute renal disease.

3-D ultrasonographic imaging of the cerebral ventricular system in very low birth weight infants

The purpose of the study was to assess reference ranges for lateral ventricular volume of very low birth weight (VLBW) infants using 3-D ultrasound (US). A total of 108 patients with birth weights < or =1500 g or mother's postmenstrual age < or =32 weeks were examined prospectively in a longitudinal study. Infants in conditions considered being potential confounders such as intraventricular haemorrhage (IVH) and periventricular leukomalacia (PVL) were not included in the calculations. Hence, 77 subjects remained for final statistical analysis. Mean postmenstrual age at birth was 194.5 (27 weeks and 5.5 days) +/- 14 SD days, mean birth weight was 972.5 +/- 236.3 SD g. Reference ranges for lateral ventricle volume were established from serial images. The exponential regression analyses revealed a weekly increase in volume of 6.3% (95% CI 4.4%-8.3%) and 6.6% (95% CI 4.7%-8.6%) in respect to the left and the right ventricle (p < 0.001). Postmenstrual age correlated significantly (p < or = 0.015) with ventricle volume. No significant association to head circumference could be determined. Establishment of reference values for the lateral ventricle volume of VLBW infants should facilitate application of 3-D US in routine diagnostics in neonatal intensive care units and detection of ventricular enlargement as a prediction of risk for poor neurodevelopmental outcome in high-risk cohorts.

Pediatric three-dimensional ultrasound: basics and potential clinical value

Three-dimensional ultrasound (3DUS) has become an established modality in some specialties; however, it has not gained significant importance in pediatric imaging. The aim of this short review article is to demonstrate and discuss promising potential applications of 3DUS in pediatric sonography. 3DUS is performed using a variety of techniques and devices, generally based on a volume reconstruction after the acquisition of a three-dimensional ultrasound (2DUS) image series, which is then viewed using various display formats. Based on our experience and a literature research, 3DUS appears to be a promising US technique for the neonatal brain and pediatric genitourinary tract. Furthermore, some other applications, such as 3DUS of the neonatal spinal canal, some soft tissue and mucsculo-skeletal queries, and tumor volume assessment, hold promising perspectives. 3DUS may reduce the imaging time of the patient, may improve the demonstration of complex anatomy, and has been shown to improve volume assessment. It furthermore holds the potential to improve standardization and documentation, as well as comparison with other sectional imaging. 3DUS also appears to be an ideal modality for training and education, as the 3D volume can be virtually rescanned at the workstation without the patient's presence. In conclusion, we believe that 3DUS is a promising imaging tool also for pediatric applications.

Three-dimensional ultrasound measurement of thyroid volume in asymptomatic male Chinese

This study was undertaken to determine the accuracy and reliability of volume measurements using 3-D ultrasound (US). Variation of thyroid gland volume with age in asymptomatic Chinese men was also investigated. Volumetric measurements of the phantoms and thyroid glands were performed with a commercially available US machine in conjunction with the 3-D SonoScan Pro workstation. Ten tissue phantoms with volumes of 1.5 to 6.5 mL were measured with 3-D US. A water displacement method was used to measure the actual volume of the phantoms. The measured volumes were compared to the actual volumes. Volumes were measured by four operators to investigate interobserver variation. Thyroid US examinations were performed in 38 asymptomatic male Chinese subjects ages 21 to 72 years. The subjects were categorized into four age groups. In each subject, the volume of the left and right lobes and the isthmus of the thyroid gland were measured with 3-D US, and any variation with age was evaluated. Results showed that the actual volume of the tissue phantoms was highly correlated with the volume measured by the four operators (r = 0.9912 to 0.9977, p < 0.05). Interobserver variation in the volumetric measurements of the tissue phantoms was not significant (ICC = 0.9861). The range of thyroid volume of the subjects was 8.81 to 17.25 mL (mean 12.78 +/- SD 2.483), and there was no significant difference in thyroid volume between subjects of different age groups (p > 0.05). 3-D US is an accurate and reliable method by which to measure thyroid volume.

Potential of three-dimensional ultrasound in neonatal and paediatric neurosonography

The aim of this study was to describe the potential of three-dimensional ultrasound (3D US) in paediatric and neonatal neurosonography. The potential applications are illustrated based on our experience in 150 patients using three different 3D US techniques at two different sites. Various disease entities throughout the paediatric age have been evaluated. The potential of 3D US, including 3D US of the cerebral vessels based on colour Doppler data, is discussed based on comparison with conventional 2D US or other imaging (as available), and with regard to the literature. In our experience, 3D US is feasible in neonatal and paediatric neurosonography. It reduces imaging time, improves demonstration of complex anatomy and vasculature, and allows for evaluation of anatomy/pathology in any plane. The 3D US furthermore improves volume assessment (e.g. in hydrocephalus), and comparison with CT, MRI and during follow-up, with a potentially improved standardisation and documentation. The 3D US additionally offers an ideal modality for training and education, as the brain and the neonatal spine can be virtually rescanned at the workstation. Yet, limitations such as areas inaccessible to 2D US, limited resolution and motion artefacts have to be acknowledged. Three-dimensional US has the potential to become a valuable additional imaging tool in paediatric neurosonography.

Potential of modern sonographic techniques in paediatric uroradiology

OBJECTIVE

To describe the potential of modern sonographic techniques in paediatric uroradiology.

METHOD

Ultrasound (US)-now being the primary imaging tool-has revolutionised imaging diagnostic in the urinary tract. Constant developments and technical refinements have secured the role of US in uroradiology. Colour Doppler Sonography (CDS) and innovative applications such as the transperineal approach or application of m-mode US to the urinary tract have helped to develop US from just a basic tool to a sophisticated and respected method. The ongoing introduction of new and even more sophisticated methods further enhance the sonographic potential, which shall be demonstrated by a more detailed discussion of these methods.

RESULTS

Harmonic imaging, extended field of view US, amplitude coded CDS, echo-enhanced US, and three-dimensional US as the most recent new sonographic techniques are successfully applicable to paediatric urinary tract disease. They improve sonographic diagnosis in many conditions, such as detection of vesico-ureteral reflux, renal parenchymal volume assessment, comprehensive visualisation of hydronephrosis and complex pathology, evaluation of renal perfusional disturbances or defects, superior documentation with improved comparability for follow-up, or simply by offering clearer tissue delineation and differentiation.

CONCLUSION

Modern US techniques are successfully applicable to neonates, infants, and children, further boosting the value of US in the paediatric urinary tract. However, as handling became more sophisticated, and artefacts have to be considered, modern urosonography became not only a more powerful, but also a more demanding method, with the need for expert knowledge and dedicated training.

Three-dimensional craniofacial reconstruction imaging

This review article aims to describe and discuss the imaging techniques most commonly used in medicine and dentistry to obtain three-dimensional images of the craniofacial complex. Three-dimensional imaging techniques provide extensive possibilities for the detailed and precise analysis of the whole craniofacial complex, for virtual (on-screen) simulation and real simulation of orthognathic surgery cases on biomodels before treatment, as well as for the detailed evaluation of the effects of treatment. Laser scanning in combination with the stereolithographic biomodeling seems to be a very promising combination for three-dimensional imaging, although there is still considerable room for improvement. Constant efforts should be made in the direction of developing and enhancing the existing techniques as well as exploring the potential for developing new methods based on emerging sectors of technology.