The True-Blue technique: Enhanced chondral assessment of the chest wall.

There is a growing understanding and identification of costal cartilage injuries, however, diagnosis of these injuries remains difficult. We present a novel radiodensity based coloring technique, termed the True-Blue technique, to manipulate 3D CT imaging and more accurately diagnose costochondral injuries.

Quantitative assessment of coat-hanger ribs detected on three-dimensional ultrasound for prenatal diagnosis of Kagami-Ogata syndrome.

Kagami-Ogata syndrome (KOS14) is a rare disease characterized by omphalocele, polyhydramnios and a bell-shaped thorax. Although the coat-hanger appearance of the ribs on postnatal X-rays is a key diagnostic finding of KOS14, its prenatal diagnosis remains challenging. We encountered a case of KOS14 diagnosed prenatally that showed omphalocele, polyhydramnios, and a bell-shaped narrow thorax. The coat-hanger angle (CHA) measured at the sixth thoracic vertebrae and the ribs using three-dimensional (3D) ultrasonography was 39°, reflecting the coat-hanger appearance of the ribs. Segmental uniparental disomy chromosome 14 (UPD(14)pat) was confirmed by a methylation analysis and microsatellite analysis after birth. The median CHA (minimum, maximum) in 25 normal fetuses was 19 (9, 26) degrees, and a sonographic CHA of 30° may be a border value for diagnosing KOS14. When the combination of omphalocele and polyhydramnios is found prenatally, 3D ultrasonography for CHA might aid in the differential diagnosis of KOS14.

Incidence of complications in the management of non-ambulatory neuromuscular early-onset scoliosis with a rib-based growing system: high- versus low-tone patients.

PURPOSE: The purpose of this study is to evaluate whether patients with high-tone neuromuscular early-onset scoliosis have different surgical outcome and complication rate, when compared to patients with low-tone neuromuscular early-onset scoliosis treated with a rib-to-pelvis rib-based dual growing system. METHODS: This is a retrospective cohort study of 67 neuromuscular early-onset scoliosis patients, collected from a multicenter database, treated with a rib-to-pelvis rib-based dual growing system. All patients were divided into two groups: high tone and low tone. Pre-, intra- and postoperative data were compared between both groups. Complications were reported by a standardized system. RESULTS: Twenty-six high-tone and 41 low-tone patients were found homogeneous regarding gender, age at surgery, weight, height, estimated blood loss and surgery time. High-tone group (19/26 = 73.1%) experiences more postoperative complications than low-tone group (22/41 = 53.7%). Most common complications were infection, device migration, death and hardware failure. Permanent abandonment of rib-based growing technique and device removal was required in 21% of high-tone patients (P < 0.001). None of the low-tone patients required abandonment. CONCLUSION: High-tone patients had more complications than those with low tone in management of neuromuscular early-onset scoliosis treated with a rib-to-pelvis rib-based dual growing system. A different surgical approach may be required to treat the high-tone neuromuscular early-onset scoliosis.

Prenatal diagnosis of fetal multiple hemivertebrae: the importance of 3D ultrasound assessment.

We herein present a case of fetal multiple hemivertebrae detected at antenatal sonography. The use of the 3 D technology supported by a new contrast enhancement rendering algorithm (Crystal Vue) has allowed the accurate prenatal classification of the defect, confirmed at follow up, that would have been difficult to define by 2 D only.

Ultrasound assessment of the anatomic landmarks for spinal anesthesia in elderly patients with hip fracture: A prospective observational study.

Tuffier line is a common landmark for spinal anesthesia. The 10th rib line has been suggested as a new landmark to predict the intervertebral levels. We evaluated the accuracy of these 2 anatomic landmarks for identifying the L4-L5 intervertebral space using ultrasonography in elderly patients with hip fracture.Seventy-nine elderly patients scheduled for hip fracture surgery under spinal anesthesia were included. In the lateral decubitus position with the fracture side up, the L4-L5 intervertebral space was identified alternately using Tuffier line, a line drawn between the highest points of both iliac crests, and the 10th rib line. The 10th rib line, an imaginary line that joints the 2 lowest points of the rib cage, passes through the L1-L2 intervertebral space or the body of L2. The L4-L5 intervertebral space was determined by the counting-down method from the 10th rib line. Then, the estimated intervertebral spaces were evaluated using ultrasonography.The L4-L5 intervertebral space was correctly identified in 47 (59%) patients with Tuffier line and 45 (57%) patients with the 10th rib line (P = .87). The estimation ratio related to the intervertebral levels was not different between the 2 landmarks (P = .40). The wrong identifications of intervertebral level with Tuffier line and the 10th rib line was observed in the following order: L3-L4 intervertebral space: 27% vs 24%, L5-S1 intervertebral space: 9% vs 16%, and L2-L3 intervertebral space: 5% vs 3%, respectively.Tuffier line and the 10th rib line may be unreliable to estimate the intervertebral space for spinal anesthesia in elderly patients with hip fracture.

A multi-method assessment of bone maintenance and loss in an Imperial Roman population: Implications for future studies of age-related bone loss in the past.

OBJECTIVES: One of the hallmarks of contemporary osteoporosis and bone loss is dramatically higher prevalence of loss and fragility in females post-menopause. In contrast, bioarchaeological studies of bone loss have found a greater diversity of age- and sex-related patterns of bone loss in past populations. We argue that the differing findings may relate to the fact that most studies use only a single methodology to quantify bone loss and do not account for the heterogeneity and complexity of bone maintenance across the skeleton and over the life course. METHODS: We test the hypothesis that bone mass and maintenance in trabecular bone sites versus cortical bone sites will show differing patterns of age-related bone loss, with cortical bone sites showing sex difference in bone loss that are similar to contemporary Western populations, and trabecular bone loss at earlier ages. We investigated this hypothesis in the Imperial Roman population of Velia using three methods: radiogrammetry of the second metacarpal (N = 71), bone histology of ribs (N = 70), and computerized tomography of trabecular bone architecture (N = 47). All three methods were used to explore sex and age differences in patterns of bone loss. RESULTS: The suite of methods utilized reveal differences in the timing of bone loss with age, but all methods found no statistically significant differences in age-related bone loss. DISCUSSION: We argue that a multi-method approach reduces the influence of confounding factors by building a reconstruction of bone turnover over the life cycle that a limited single-method project cannot provide. The implications of using multiple methods beyond studies of bone loss are also discussed.

Assessment of cortical bone thickness using ultrasound.

PURPOSE: The aim of the study was to analyze the accuracy of measuring the cortical bone thickness using a combination of low- and high-frequency ultrasound (US) compared with cone-beam computed tomography (CBCT) and using stereomicroscopy as reference method. MATERIAL AND METHODS: Ten jawbone models were prepared using bovine ribs and porcine gingiva. A dental implant was placed in each model. All models were investigated by US, CBCT, and stereomicroscopy. The cortical bone thickness was measured directly above and 4 mm beside the implant with each method in different slices. RESULTS: The median deviation of US measurements compared to the reference method was 0.23 mm. The CBCT method was slightly more accurate (median percent deviation of 9.2%) than the US method (10.3%). However, US measurements directly above the implant were more accurate than CBCT measurements with a median percent deviation of 10.5% for US vs. 11.8% for CBCT. CONCLUSION: Ultrasound showed a high potential to supplement CBCT for measurements of the cortical bone thickness.

Rib Cartilage Assessment Relative to the Healthy Ear in Young Children with Microtia Guiding Operative Timing.

BACKGROUND: The optimal age at which to initiate for auricular reconstruction is controversial. Rib cartilage growth is closely related to age and determines the feasibility and outcomes of auricular reconstruction. We developed a method to guide the timing of auricular reconstruction in children with microtia ranging in age from 5 to 10 years. METHODS: Rib cartilage and the healthy ear were assessed using low-dose multi-slice computed tomography. The lengths of the eighth rib cartilage and the helix of the healthy ear (from the helical crus to the joint of the helix and the earlobe) were measured. Surgery was performed when the two lengths were approximately equal. RESULTS: The preoperative eighth rib measurements significantly correlated with the intraoperative measurements (P < 0.05). From 5 to 10 years of age, eighth rib growth was not linear. In 76 (62.8%) of 121 patients, the eighth rib length was approximately equal to the helix length in the healthy ear; satisfactory outcomes were achieved in these patients. In 18 (14.9%) patients, the eighth rib was slightly shorter than the helix, helix fabrication was accomplished by adjusting the length of the helical crus of stent, and satisfactory outcomes were also achieved. Acceptable outcomes were achieved in 17 (14.0%) patients in whom helix fabrication was accomplished by cartilage splicing. In 9 (7.4%) patients with insufficient rib cartilage length, the operation was delayed. In one (0.8%) patient with insufficient rib cartilage length, which left no cartilage for helix splicing, the result was unsatisfactory. CONCLUSIONS: Eighth rib cartilage growth is variable. Rib cartilage assessment relative to the healthy ear can guide auricular reconstruction and personalize treatment in young patients with microtia.

Effect of anatomical landmark perturbation on mean helical axis parameters of in vivo upper costovertebral joints.

The literature concerning quantification of costovertebral joint (CVJ) motion under in vivo conditions is scarce. Most papers concerning this topic are related to ex vivo loading conditions. In vivo protocols are available from the literature to determine rib and vertebra kinematics but new developments are needed to improve data processing concerning CVJ behaviour obtained from discrete breathing positions showing limiting ranges-of-motion and sensitive to noise. Data from previous work were used to implement a method analyzing mean helical axis (MHA) and pivot point parameters of the CVJ complexes. Several levels of noises were estimated within Monte-Carlo simulations to optimize MHA results. MHA parameters were then used to transform and define a CVJ-specific local coordinate system. This study proposes an improvement for CVJ kinematics processing and description from in vivo data obtained from computed tomography. This methodology emphasizes the possibility to work with variability of MHA parameters using Monte-Carlo procedures on anatomical landmark coordinates and to define a local coordinate system from this particular joint behaviour. Results from the CVJ joint model are closer to a hinge joint (secondary motions inferior to 3°) when anatomical frames are expressed from MHA orientation. MHA orientation and position data obtained from the proposed method are relevant according to angular dispersion obtained (from 7.5° to 13.9°) and therefore relevant to define behaviour of CVJ.

Radiographic, clinical, and patients' assessment of segmental direct vertebral body derotation versus simple rod derotation in main thoracic adolescent idiopathic scoliosis: a prospective, comparative cohort study.

PURPOSE: The application of vertebral body derotation (DVBD) is still controversial by now; the purpose of this prospective cohort study was to compare comprehensive outcomes between segmental DVBD and simple rod derotation (SRD) especially in main thoracic adolescent idiopathic scoliosis. METHODS: 36 patients in DVBD group and 45 patients in SRD group were with a 2-year follow-up. Among them, 19 DVBD patients and 16 SRD patients received CT scan examinations. RESULTS: There were no significant difference between the groups in preoperative main thoracic Cobb, apical vertebral rotation and rib hump. Apical vertebral rotation measured from CT scans was 9.7° ± 2.0° versus 15.3° ± 2.4° (p < 0.001) postoperatively in the DVBD and SRD patients, respectively. At 2-year follow-up, the main thoracic Cobb was 14.2° ± 1.6° versus 14.7° ± 1.7° (p = 0.18), rib hump was 6.4° ± 3.8° versus 6.8° ± 3.1° (p = 0.60) in DVBD group and SRD group. Patients' assessments of both groups were improved in Spinal Appearance Questionnaire (SAQ) and Scoliosis Research Society-22 Questionnaire (SRS-22), but showed no significant difference at follow-up (p = 0.47 and 0.60). CONCLUSION: Although segmental DVBD showed excellent radiographic correction of axial spinal deformity postoperatively, there was no more correction of clinical rib hump or better patients' assessment than SRD at follow-up in our data.

Use of EOS imaging for the assessment of scoliosis deformities: application to postoperative 3D quantitative analysis of the trunk.

PURPOSE: EOS imaging system is accessible to clinicians since 2007, allowing 3D spinal reconstructions in a functional standing position with reduced radiation. However, numerous ongoing research protocols continuously help implementing the dedicated software. The main principle and applications of the EOS device are discussed here, with an emphasis on future projects. In particular, the authors studied the postoperative modification of the rib cage and spinal morphology after posteromedial correction, in a consecutive series of adolescent idiopathic scoliosis (AIS) patients. METHODS: 49 thoracic AIS patients underwent low-dose stereoradiography preoperatively, postoperatively and at latest examination, with a minimum 2-year follow-up. Spinal and rib cages 3D reconstructions were obtained using dedicated software, and the postoperative modification of thoracic parameters was reported. RESULTS: All parameters were significantly improved after surgery. Mean thoracic volume increase was 8.4% (±8), influenced by the postoperative derotation of the apical vertebra. No difference was found in thoracic volume increase in patients who gained more than 10° of thoracic kyphosis. A significant correlation was found between spinal penetration index at the apex and thoracic sagittal alignment (p = 0.02). CONCLUSIONS: EOS imaging device now reliably provides a global 3D quantitative analysis of scoliotic deformities in a context of routine clinical use. This innovative tool will help in the future to better understand scoliosis physiopathology and to evaluate treatment strategies.

Non-destructive assessment of human ribs mechanical properties using quantitative ultrasound.

Advanced finite element models of the thorax have been developed to study, for example, the effects of car crashes. While there is a need for material properties to parameterize such models, specific properties are largely missing. Non-destructive techniques applicable in vivo would, therefore, be of interest to support further development of thorax models. The only non-destructive technique available today to derive rib bone properties would be based on quantitative computed tomography that measures bone mineral density. However, this approach is limited by the radiation dose. Bidirectional ultrasound axial transmission was developed on long bones ex vivo and used to assess in vivo health status of the radius. However, it is currently unknown if the ribs are good candidates for such a measurement. Therefore, the goal of this study is to evaluate the relationship between ex vivo ultrasonic measurements (axial transmission) and the mechanical properties of human ribs to determine if the mechanical properties of the ribs can be quantified non-destructively. The results show statistically significant relationships between the ultrasonic measurements and mechanical properties of the ribs. These results are promising with respect to a non-destructive and non-ionizing assessment of rib mechanical properties. This ex vivo study is a first step toward in vivo studies to derive subject-specific rib properties.

The diagnostic utility of rib series in assessing rib fractures.

Rib series rarely add information to the posteroanterior (PA) film for the diagnosis of rib fractures. In this investigation, we evaluated the utility of rib X-rays using turnaround time (TAT), radiation exposure, and cost-efficiency as the key parameters. This investigation was conducted from January 2008 to December 2012. We included patients who had rib series performed for suspected rib fractures. TAT for patients was calculated from the time exam was ordered by the emergency department (ED) physician/staff to time the report was finalized by the attending radiologist. Effective radiation dose for rib series was calculated as a summation of radiation dose from the standard rib series images for each patient. Cost-efficiency was determined based on the number of interventions that took place as a result of a complicated study. Our investigation consisted of 422 patients, 208 females aged (57 ± 20.8) and 214 males aged (48 ± 17.3). A total of 74(17.5 %) abnormal findings were noted, out of which only 1(0.23 %) underwent management change. The mean turnaround time for patients undergoing rib series had a value of 133.5 (±129.8) min as opposed to a single chest PA of 61.8(± 64) min. Average effective radiation dose for a rib series was 0.105 (±0.04) mSv, whereas average effective radiation dose of a single chest PA was 0.02 mSv. Dedicated rib series has a low-yield diagnostic value as it pertains to management change. The overall impact on patient care based on our findings is small when compared to the risks associated with prolonged TAT, repeated exposure to radiation, and extensive medical costs.

Personalized 3D reconstruction of the rib cage for clinical assessment of trunk deformities.

Scoliosis is a 3D deformity of the spine and rib cage. Extensive validation of 3D reconstruction methods of the spine from biplanar radiography has already been published. In this article, we propose a novel method to reconstruct the rib cage, using the same biplanar views as for the 3D reconstruction of the spine, to allow clinical assessment of whole trunk deformities. This technique uses a semi-automatic segmentation of the ribs in the postero-anterior X-ray view and an interactive segmentation of partial rib edges in the lateral view. The rib midlines are automatically extracted in 2D and reconstructed in 3D using the epipolar geometry. For the ribs not visible in the lateral view, the method predicts their 3D shape. The accuracy of the proposed method has been assessed using data obtained from a synthetic bone model as a gold standard and has also been evaluated using data of real patients with scoliotic deformities. Results show that the reconstructed ribs enable a reliable evaluation of the rib axial rotation, which will allow a 3D clinical assessment of the spine and rib cage deformities.

Multislice computed tomography of the first rib: a useful technique for bone age assessment.

Macroscopic study of the first rib has been described by Kunos et al. as an efficient method of age estimation. We retrospectively reviewed a test sample of 160 first right ribs obtained from multislice computed tomography (MSCT) clinical investigations of living individuals aged 15-30 years old. Based on the descriptions of Kunos et al., we analyzed the morphological appearance of the sternal end of the first rib on two- and three-dimensional MSCT reconstructions and defined changes in appearance in stages (from 2 to 5). We also studied the calcification and ossification of the costal cartilage as an independent feature. By statistical analysis (ANOVA), we determined for each gender the correlation between the estimated stage of the costal face, the appearance of the costal cartilage, and the documented age of the subjects. We demonstrated that MSCT of the first rib appears to be an efficient noninvasive modality for bone age estimation.

Breast patient setup error assessment: comparison of electronic portal image devices and cone-beam computed tomography matching results.

PURPOSE: To quantify the differences in setup errors measured with the cone-beam computed tomography (CBCT) and electronic portal image devices (EPID) in breast cancer patients. METHODS AND MATERIALS: Repeat CBCT scan were acquired for routine offline setup verification in 20 breast cancer patients. During the CBCT imaging fractions, EPID images of the treatment beams were recorded. Registrations of the bony anatomy for CBCT to planning CT and EPID to digitally reconstructed-radiographs (DRRs) were compared. In addition, similar measurements of an anthropomorphic thorax phantom were acquired. Bland-Altman and linear regression analysis were performed for clinical and phantom registrations. Systematic and random setup errors were quantified for CBCT and EPID-driven correction protocols in the EPID coordinate system (U, V), with V parallel to the cranial-caudal axis and U perpendicular to V and the central beam axis. RESULTS: Bland-Altman analysis of clinical EPID and CBCT registrations yielded 4 to 6-mm limits of agreement, indicating that both methods were not compatible. The EPID-based setup errors were smaller than the CBCT-based setup errors. Phantom measurements showed that CBCT accurately measures setup error whereas EPID underestimates setup errors in the cranial-caudal direction. In the clinical measurements, the residual bony anatomy setup errors after offline CBCT-based corrections were Σ(U) = 1.4 mm, Σ(V) = 1.7 mm, and σ(U) = 2.6 mm, σ(V) = 3.1 mm. Residual setup errors of EPID driven corrections corrected for underestimation were estimated at Σ(U) = 2.2mm, Σ(V) = 3.3 mm, and σ(U) = 2.9 mm, σ(V) = 2.9 mm. CONCLUSION: EPID registration underestimated the actual bony anatomy setup error in breast cancer patients by 20% to 50%. Using CBCT decreased setup uncertainties significantly.

Morphometric comparisons between the pedicle and the pedicle rib unit in the immature Chinese thoracic spine: a computed tomographic assessment.

STUDY DESIGN: Morphology comparisons between the pedicle and pedicle rib unit in the immature spine were conducted through computed tomographic scans. OBJECTIVE: To establish reference data concerning the dimensions of the pedicle rib unit for normal children. SUMMARY OF BACKGROUND DATA: Until recently, studies on extrapedicular fixation were mostly based on adults. No published study has assessed the morphology of the pedicle rib unit in the normal immature population. Establishment of the basic morphometric characteristics may be beneficial in treating immature patients with spinal disorders. METHODS: Measurements were carried out on the chest computed tomography scans of the immature Chinese patients without any spinal disorder findings. The width, chord length, and transverse angle of the pedicle rib unit were obtained and compared with the corresponding pedicle index. Difference between sex groups was measured, and significant statistical correlations were carefully studied to determine potentially important clinical relationships. RESULTS: The mean values and the standard deviations obtained for each thoracic segment were determined. The width, chord length, and transverse angle of the pedicle rib unit were significantly larger than corresponding pedicle measurements at all levels. Significant difference for measurements between sexes was found at some segments. Compared with the sex, age seemed to have a more significant effect on the measurements. Linear pedicle and pedicle rib unit dimensions had good correlations with age, whereas the transverse angle seemed to change little with age. CONCLUSION: Compared with the dimensions of the immature pedicle, the significantly larger size of the corresponding pedicle rib unit provides a more ample space, which accommodates screws with larger diameters. Extrapedicular vertebral body fixation was anatomically feasible for the immature spine. The new procedure should be cautiously applied to avoid potential implant failures or a new deformity because of the growth of the immature spine.

The blood supply of early, late, and nonossifying cartilage: preliminary gray-scale and Doppler assessment and their implications.

BACKGROUND: Comparative gray-scale Doppler US studies of various cartilages have not been reported before. OBJECTIVE: To study gray-scale US and perfusion patterns of different cartilages. MATERIALS AND METHODS: Three groups of cartilages were studied in 42 normal neonates. Group A included the proximal femoral chondroepiphysis of 20 neonates as well as proximal humeral, distal femoral, and proximal tibial epiphyses of 8 others. Group B included the patellar cartilage of nine neonates and group C included the rib cartilage of five neonates. RESULTS: Early ossifying cartilages all had numerous echogenic columns on US. Late ossifying patellar cartilage was amorphous and hypoechoic at birth but contained echogenic columns near the ossification age. Rib cartilage was hypoechoic and amorphous at all ages. The blood supply was detectable in all cartilages except the ribs. Peak systolic velocities increased with age in the proximal femoral epiphysis. The patellar cartilage was less vascular than the distal femoral epiphysis at birth, but more vascular at 14-24 months of age. The rib cartilage did not have any discernable blood supply at any age. CONCLUSIONS: Cartilage blood flow is detectable with current technology. Cartilage blood flow correlates with the timing of its ossification. Normal cartilage blood flow may prognosticate normality of its growth and development potential.

Monte carlo evaluation of the AAA treatment planning algorithm in a heterogeneous multilayer phantom and IMRT clinical treatments for an Elekta SL25 linear accelerator.

The Anisotropic Analytical Algorithm (AAA) is a new pencil beam convolution/superposition algorithm proposed by Varian for photon dose calculations. The configuration of AAA depends on linear accelerator design and specifications. The purpose of this study was to investigate the accuracy of AAA for an Elekta SL25 linear accelerator for small fields and intensity modulated radiation therapy (IMRT) treatments in inhomogeneous media. The accuracy of AAA was evaluated in two studies. First, AAA was compared both with Monte Carlo (MC) and the measurements in an inhomogeneous phantom simulating lung equivalent tissues and bone ribs. The algorithm was tested under lateral electronic disequilibrium conditions, using small fields (2 x 2 cm(2)). Good agreement was generally achieved for depth dose and profiles, with deviations generally below 3% in lung inhomogeneities and below 5% at interfaces. However, the effects of attenuation and scattering close to the bone ribs were not fully taken into account by AAA, and small inhomogeneities may lead to planning errors. Second, AAA and MC were compared for IMRT plans in clinical conditions, i.e., dose calculations in a computed tomography scan of a patient. One ethmoid tumor, one orophaxynx and two lung tumors are presented in this paper. Small differences were found between the dose volume histograms. For instance, a 1.7% difference for the mean planning target volume dose was obtained for the ethmoid case. Since better agreement was achieved for the same plans but in homogeneous conditions, these differences must be attributed to the handling of inhomogeneities by AAA. Therefore, inherent assumptions of the algorithm, principally the assumption of independent depth and lateral directions in the scaling of the kernels, were slightly influencing AAA's validity in inhomogeneities. However, AAA showed a good accuracy overall and a great ability to handle small fields in inhomogeneous media compared to other pencil beam convolution algorithms.

Contribution of three-dimensional computed tomography in the assessment of fetal skeletal dysplasia.

OBJECTIVE: To compare the diagnostic accuracy of two-dimensional (2D) ultrasound and three-dimensional (3D) computed tomography (CT) for the diagnosis of fetal skeletal anomalies. METHODS: Eleven pregnant women underwent 2D ultrasound and 3D-CT. Ten fetuses presented skeletal anomalies on 2D ultrasound and one fetus had a normal ultrasound exam but a familial history of osteopetrosis. We compared retrospectively the diagnoses established on 2D ultrasound and 3D-CT with the neonatal and/or postmortem work-up, which were used as the gold standard. RESULTS: 2D ultrasound provided the correct diagnosis in only two of the 11 cases. CT yielded the correct diagnosis in eight; in six of these, 2D ultrasound had been inconclusive. 3D-CT was more accurate than was 2D ultrasound in visualizing vertebral anomalies (abnormal shape of the vertebral bodies, abnormal interpedicular distance), pelvic bone malformations (delayed ossification of the pubic bones, abnormal acetabular shape) and enlarged metaphysis or synostoses in long bones. In three cases, neither 2D ultrasound nor CT provided the correct diagnosis. CONCLUSION: In this series, which included a variety of skeletal dysplasias, 3D-CT had a better diagnostic yield than did 2D ultrasound. Both imaging techniques are useful in the management of fetal dysplasia; 2D ultrasound is a useful screening test and 3D-CT is a valuable complementary diagnostic tool.