Clinical utility of three-dimensional US

Can 3-dimensional cranial ultrasound be used to successfully reconstruct a 2-dimensional image without compromising on image quality in a neonatal population?

BACKGROUND

Cranial ultrasound is frequently performed in neonatal intensive care units and acquiring 2-dimensional (D) images requires significant training. Three-D ultrasound images can be acquired semi-automatically.

OBJECTIVE

This proof-of-concept study aimed to demonstrate that 3-D study image quality compares well with 2-D. If this is successful, 3-D images could be acquired in remote areas and read remotely by experts.

MATERIALS AND METHODS

This was a prospective study of 20 neonates, who underwent both routine 2-D and 3-D cranial ultrasounds. Images were reconstructed into standard views extracted from the 3-D volume and evaluated by three radiologists blinded to the acquisition method. The radiologists assessed for the presence of anatomical landmarks and overall image quality.

RESULTS

More anatomical structures were identified in the 3-D studies (P<0.01). There was a trend that 3-D ultrasound demonstrated better image quality in the coronal plane, and 2-D in the sagittal plane, only reaching statistical significance for two coronal views and two sagittal views.

CONCLUSION

Overall, this study has demonstrated that 3-D cranial ultrasound performs similarly to 2-D and could be implemented into neonatal practice.

Use of 3D ultrasound to characterise temporal changes in thyroid nodules: an in vitro study

OBJECTIVE

Thyroid nodules are extremely common, with prevalence rate up to 68%, yet only 7-15% of these are malignant. Many nodules require surveillance and 2-dimensional ultrasound (2D US) is used. Issues include the huge workload of obtaining and labeling images and difficulty comparing sizes of nodules over time due to large inter-operator variability. Inaccuracies may result in unnecessary FNAC or missed diagnosis of malignant nodules.

METHODS

We compared two techniques: freehand plain 2D US against freehand 2D US with gyroscopic guidance, both followed by 3D reconstruction using software. We measured the volume of nodules and a normal thyroid gland.

RESULTS

We found 2D US with gyroscopic guidance to be superior to plain 2D US as 3D reconstructions of greater accuracy are produced. The volume of the thyroid lobe measured 8.42 cm3 ± 0.94 was reasonably close to the normal average volume. However, the measured volume of the ellipsoidal nodule by the software is 8.69 cm3 ± 0.97 while the measured volume of the spherical nodule is 7.09 cm3 ± 0.79. As the expected volume of the nodules were 4.24cm3 and 4.19 cm3 respectively, the measured volume of the nodule was not accurate. The time taken to characterise nodules was reduced greatly from over 30 min in usual procedure to less than 10 min.

CONCLUSION

We find 3D US promising for evaluating size of thyroid nodules, with potential to study other TIRAD characteristics. Freehand 2D US with gyroscopic guidance shows the most promise for producing reliable, accurate and faster 3D reconstructions of thyroid nodules.

Advances in Imaging for Assessing Pelvic Endometriosis

In recent years, due to the development of standardized diagnostic protocols associated with an improvement in the associated technology, the diagnosis of pelvic endometriosis using imaging is becoming a reality. In particular, transvaginal ultrasound and magnetic resonance are today the two imaging techniques that can accurately identify the majority of the phenotypes of endometriosis. This review focuses not only on these most common imaging modalities but also on some additional radiological techniques that were proposed for rectosigmoid colon endometriosis, such as double-contrast barium enema, rectal endoscopic ultrasonography, multidetector computed tomography enema, computed tomography colonography and positron emission tomography-computed tomography with 16α-[18F]fluoro-17β-estradiol.

Measuring intraobserver and intermethod reliability of endometriotic cyst volumes: A comparison between MRI and 3D transvaginal ultrasound in endometriosis

Objectives:

To identify the intraobserver and intermethod reliability of three-dimensional transvaginal ultrasound (3D-TVUS) using the software VOCAL and XI VOCAL compared with magnetic resonance imaging (MRI) for volumetric measurement of ovarian endometrioma.

Methods:

The intermethod and intraobserver reliability of endometrioma volumes were assessed in 16 women diagnosed with endometriosis through laparoscopy with histologic confirmation and presenting with uni- or bilateral endometriomas. In total, volumes of 23 endometriomas were assessed with two-dimensional and three-dimensional transvaginal ultrasound and 6 mm magnetic resonance imaging. Examinations took place at two moments in one menstrual cycle: day 2–4 (T0) and day 20–22 (T1).

Results:

The intraclass correlation for intraobserver reliability is good to very good for all three techniques ranging from the lowest value of 0.953 to the highest of 1.000. MRI has the most narrow limits of agreement (−3.93 to 4.53), followed by XI VOCAL (−5.16 to 5.65) while VOCAL has the widest limits of agreement (−10.22 to 11.39). Intraclass correlations are poor in the comparison of XI VOCAL to MRI, moderate between VOCAL and XI VOCAL, and good for the comparison between VOCAL and MRI. Limits of agreement vary per technique. When comparing 3D imaging techniques with 2D TVUS, XI VOCAL versus 2D TVUS provide the smallest limits of agreement.

Conclusions:

MRI and XI VOCAL provide the best intraobserver reliability. The different imaging techniques are not interchangeable. As TVUS is a more readily available and cost-efficient imaging technique the usage of XI VOCAL is advised.

New frontiers in liver ultrasound: From mono to multi parametricity

Modern liver ultrasonography (US) has become a “one-stop shop” able to provide not only anatomic and morphologic but also functional information about vascularity, stiffness and other various liver tissue properties. Modern US techniques allow a quantitative assessment of various liver diseases. US scanning is no more limited to the visualized plane, but three-dimensional, volumetric acquisition and consequent post-processing are also possible. Further, US scan can be consistently merged and visualized in real time with Computed Tomography and Magnetic Resonance Imaging examinations. Effective and safe microbubble-based contrast agents allow a real time, dynamic study of contrast kinetic for the detection and characterization of focal liver lesions. Ultrasound can be used to guide loco-regional treatment of liver malignancies and to assess tumoral response either to interventional procedures or medical therapies. Microbubbles may also carry and deliver drugs under ultrasound exposure. US plays a crucial role in diagnosing, treating and monitoring focal and diffuse liver disease. On the basis of personal experience and literature data, this paper is aimed to review the main topics involving recent advances in the field of liver ultrasound.

Three-dimensional Ultrasound Volume and Conventional Ultrasound Diameter Changes are Equally Good Markers of Endoleak in Follow-up after Endovascular Aneurysm Repair

INTRODUCTION

The main disadvantages of computed tomography angiography in follow-up after endovascular aneurysm repair are the risks of contrast-induced renal impairment and radiation-induced cancer. Three-dimensional ultrasound is a new technique for volume estimation of the aneurysm sac. Some studies have reported promising results. The aim of this study was to evaluate the accuracy and precision of three-dimensional ultrasound aneurysm sac-volume estimates, and to explore whether volume and/or diameter changes on ultrasound can be used as markers of endoleak.

METHODS

A single-center diagnostic accuracy study was performed. 92 Patients planned for endovascular aneurysm repair were prospectively and consecutively enrolled (2013-2016). Aneurysm sac diameter and volume were measured using computed tomography angiography, conventional ultrasound, and three-dimensional ultrasound preoperatively and 1, 6, 12, and 24 months postoperatively. Three-dimensional ultrasound was performed with a commercially available electromechanical transducer. Patients with endoleak were observed 5 years after endovascular aneurysm repair.

RESULTS

79 men and 13 women were included. Mean age was 74 years (57-92). Median follow-up was 24 months. Endoleak cases were observed for up to 55 months. Diameter measurements on conventional ultrasound correlated well with CT diameters (r = 0.9, P < 0.05, n = 347), and Bland-Altman analyses showed an upper limit of agreement of +0.5 cm and a lower limit of agreement of -0.8 cm. The mean difference was -0.13 cm ± 0.36 cm. Three-dimensional ultrasound volumes had a correlation with computed tomography angiography diameters of r = 0.8 (P < 0.05, n = 347) and with three-dimensional computed tomography volumes of r = 0.8 (P < 0.05, n = 155). Receiver operating characteristic analyses showed that the diameter and volume changes which led to reintervention were most accurate at 24-month follow-up, with area-under-the-curve percentage changes of 0.98 (two-dimensional ultrasound), 0.97 (three-dimensional ultrasound), and 0.97 (two-dimensional computed tomography).

DISCUSSION

Both diameter and volume changes can be used as markers for endoleak with excellent areas under the curve on receiver operating characteristic analyses. However, three-dimensional ultrasound volumes did not add any further diagnostic information. Conventional 2D diameter measurements were as accurate as volume changes as markers of endoleak.

CONCLUSION

Type II endoleaks can safely be followed up using a simple diameter measurement on conventional ultrasound.

Focal liver lesions: interobserver and intraobserver agreement of three-dimensional contrast-enhanced ultrasound-assisted volume measurements

PURPOSE

This study was conducted to assess the interobserver and intraobserver agreement of three-dimensional contrast-enhanced ultrasound (3D-CEUS) volume calculations of focal liver lesions (FLLs).

METHODS

Thirty-nine patients (15 men and 24 women; mean age, 55.4 years) with 39 FLLs (mean size, 3.1±1.8 cm; size range, 1 to 8 cm) prospectively underwent 3D-CEUS. Four readers calculated the volume of each lesion in an independent and blinded fashion in two separate sessions by means of a semi-automatic, commercially available proprietary software. The differences in lesion volumes (cm3) among sessions and readers were assessed using the Mann-Whitney U test and the Kruskal-Wallis test. Bland-Altman analysis was also performed. Intraclass correlation coefficients (ICCs) with 95% confidence intervals (95% CIs) were calculated. The statistical significance level was set at P<0.05.

RESULTS

Among readers, there were no statistically significant differences in the first (P=0.953) and second (P=0.592) reading sessions for volume calculations of the 39 FLLs, with almost perfect inter-reader agreement (ICC values of the first reading session, 0.996; 95% CI, 0.992 to 0.998 and ICC value of the second reading session, 0.994; 95% CI, 0.990 to 0.997, respectively). For each of the four readers, there were no significant differences in volume calculations between the two sessions (P=0.503-0.924), and the intrareader agreement was almost perfect for each reader (R1: ICC, 0.995; 95% CI, 0.991 to 0.998; R2: ICC, 0.995; 95% CI, 0.988 to 0.997; R3: ICC, 0.996; 95% CI, 0.992 to 0.998; R4: ICC, 0.985; 95% CI, 0.971 to 0.992).

CONCLUSION

3D-CEUS volume calculations provided consistent measurements across different readers with almost perfect intrareader agreement.

Diagnostic Performances of Tridimensional Rectosonography and Magnetic Resonance Imaging in Rectosigmoid Endometriosis: A Prospective Cohort Study on 101 Patients

Tridimensional rectosonography (3-D RSG) is a transvaginal ultrasonography procedure combining intrarectal contrast with tridimensional technology. The objectives of this study were to assess the diagnostic performances of 3-D RSG in deep infiltrating rectosigmoid endometriosis using surgery and pathology as the gold standard, and to compare its results with those of magnetic resonance imaging (MRI). Patients referred for endometriosis with symptoms suggesting deep infiltrating intestinal endometriosis (DIE) were included if they agreed to undergo a 3-D RSG and MRI and if there was a surgical indication related to endometriosis. The study was a non-randomized monocentric prospective cohort study (Canadian task force classification Level II-2). From May 2012 to May 2017, 101 patients were included. Sixty patients (59.4%) had bowel involvement of the rectum (n = 21, 20.8%) or of the sigmoid (n = 39, 38.6%) confirmed in surgery and/or in pathologic testing. In the diagnosis of rectosigmoid DIE, 3-D RSG sensitivity, specificity, positive predictive value, negative predictive value, accuracy and κ index were 93%, 95%, 97%, 91%, 94% and 0.88, respectively. For MRI they were 87%, 90%, 93%, 82%, 88% and 0.76, respectively. The accuracy was not significantly different between 3-D RSG and MRI (p = 0.181). In conclusion, 3-D RSG is an effective technique to diagnose rectosigmoid endometriosis and seems to have similar diagnostic performances to MRI for this indication.

Prospective evaluation of 4-D contrast-enhanced-ultrasound (CEUS) imaging in bladder tumors

PURPOSE

The evaluation of the potential clinical benefit of four-dimensional ultrasound (4D-US) in the assessment of bladder cancer (BC).

MATERIAL AND METHODS

20 patients with indication for cystoscopy for suspicion of bladder cancer were prospectively included in this study. All patients underwent two-dimensional ultrasound (2D-US), contrast enhanced ultrasound (CEUS) and real-time four-dimensional ultrasound (4D-US). All acquisitions were compared to each other in regard to image quality. This assessment was done using a 6 point scale (1 = best). All patients underwent subsequently cystoscopy with resection of the tumor (TURB), due a histopathological analysis was possible.

RESULTS

All examinations were performed successfully and no patient had to be excluded from the study. Patients acceptance of 4D-US was consistently good. No adverse events occurred. Image quality of real time 4D-US (score: 1.27±0.46) was significantly superior (p < 0.001) to both, conventional 2D-US (score: 2.33±0.62) and also to 2D-CEUS (score: 2.00±0.53). In terms of tumor detection no superiority was evident for 4D-US compared to 2D-US or in utilization of CEUS (sensitivity = 0.89; specificity = 1.00; positive predictive value = 1.00; negative predictive value = 0.50; AUC = 0.944; (95% CI: 07.43-0.998)).

CONCLUSION

The assessment of bladder cancer using real time 4D-US is feasible and improves the image quality and therefore also the precise anatomical consistency of intravesical tumor masses.

Diagnostic value of 3D power Doppler ultrasound in the characterization of thyroid nodules

Background/aim

This study aimed to evaluate the diagnostic value of vascular indices obtained using 3D power Doppler ultrasound (3D PDUS) in differentiation of benign and malignant thyroid nodules.

Materials and methods

Sixty-seven patients (56 female, 11 male, mean age 44.6) with 81 thyroid nodules exhibiting mixed (peripheral and central) vascularization patterns, with the largest diameter between 10 and 30 mm, were prospectively evaluated using 3D PDUS. Nodule volume, vascularization index (VI), flow index (FI), and vascularization flow index (VFI) were calculated using the Virtual Organ Computer-aided Analysis (VOCAL) software, and these indices were then compared with regard to the cytohistopathology-based diagnosis. The optimum cutoff values for the differentiation of benign and malignant nodules were identified, and diagnostic efficacy was calculated using receiver operating characteristic (ROC) analysis.

Results

Fifty-six of the 81 nodules included in this study were diagnosed as benign and 25 as malignant. Vascular indices in malignant nodules were significantly higher than those in benign nodules (P < 0.05). In benign nodules, the mean VI was 11.61 ± 6.88, mean FI was 39.75 ± 3.93, and mean VFI was 4.82 ± 2.94, compared to 18.64 ± 12.81, 41.82 ± 4.43, and 8.17 ± 6.37, respectively, in malignant nodules. The area under the curves (AUCs) was calculated as 0.68, 0.61, and 0.67 for VI, FI, and VFI, respectively. At optimal cutoff values of 10.2 for VI, 40.8 for FI, and 5.5 for VFI, the sensitivity and specificity were 72%/55.4%, 68%/57.1%, and 68%/67.9%, respectively.

Conclusion

3D PDUS can be useful in the characterization of thyroid nodules.

Effectiveness of 3-dimensional shoulder ultrasound in the diagnosis of rotator cuff tears: A meta-analysis

BACKGROUND

Numerous quantitatively based studies measuring the accuracy of 3D shoulder ultrasound (US) for the diagnosis of rotator cuff tears remain inconclusive. In order to determine how effective 3D shoulder US is for detecting rotator cuff tears, a meta-analysis was performed systematically.

METHODS

Six electronic databases, PubMed/Medline, Embase, Cochrane Library, CNKI, VIP data, and Wanfang data, were utilized to retrieve articles praising the diagnostic value of 3D shoulder US for use in detecting rotator cuff tears. After screening and diluting out the articles that met inclusion criteria to be used for statistical analysis, the pooled evaluation indexes including sensitivity, specificity, and diagnostic odds ratio (DOR) as well as the summary receiver operating characteristic curve (SROC) were calculated utilizing Meta-Disc v.1.4.

RESULTS

Screening determined that out of 4220, 7 studies involving a total of 282 patients were deemed viable for inclusion in the meta-analysis. The results of the analysis showed that the sensitivity and specificity were at 94% and 83%, respectively, with a DOR of 60.06, Q* index of 0.9058 and the area under SROC of 0.9609. Additionally, a satisfactory accuracy of 3D shoulder US was observed in detecting full- and partial-thickness rotator cuff tears.

CONCLUSION

This meta-analysis suggests that 3D shoulder US is very effective and highly accurate to detect full-thickness rotator cuff tears, but may lack accuracy in the diagnosis of partial tears.

Three-Dimensional Shear Wave Elastography of Skeletal Muscle: Preliminary Study

OBJECTIVES

Two-dimensional (2D) shear wave elastography (SWE) can measure the elasticity of skeletal muscle, tendons, and ligaments. Three-dimensional (3D) SWE has been used to detect breast cancer but has not been applied to the musculoskeletal system. This study aimed to investigate whether 3D SWE could be used in skeletal muscles in vivo.

METHODS

The study enrolled 20 healthy volunteers at Beijing Chaoyang Hospital from August to October 2016. Two-dimensional and 3D SWE scans were used to measure the Young modulus of the flexor carpi radialis in the relaxed state. Longitudinal and transverse scanning was performed. Data were analyzed by a 1-way analysis of variance/least significant difference post hoc test, a paired t test, and Bland-Altman plots.

RESULTS

The participants included 10 male and 10 female volunteers with a mean age ± SD of 25 ± 5 years. The Young modulus did not differ between 3D and 2D SWE for the sagittal plane (longitudinal scanning, 34.9 ± 5.7 versus 32.7 ± 5.2 kPa; P = .096) or transverse plane (transverse scanning, 9.1 ± 2.1 versus 9.2 ± 1.6 kPa; P = .877). The Young modulus did not differ between sagittal, transverse, and coronal planes for 3D SWE longitudinal scanning (34.9 ± 5.7, 34.3 ± 5.8, and 34.8 ± 5.9 kPa, respectively; P = .936) or 3D SWE transverse scanning (9.1 ± 2.0, 9.1 ± 2.1, and 8.8 ± 2.1 kPa; P = .838). However, the Young modulus for each individual plane (sagittal, transverse, or coronal) differed significantly between longitudinal and transverse scanning (P < .001).

CONCLUSIONS

Both 2D SWE and 3D SWE are suitable techniques for clinical use, depending on the examiner's experience/preference. However, 3D SWE provides a multiplanar/multislice view that better illustrates the spatial characteristics of muscle tissue. Three-dimensional SWE may be a new method for fully visualizing the musculoskeletal system.

Three-Dimensional Virtual Sonographic Cystoscopy for Detection of Ureterocele in Duplicated Collecting Systems in Children

OBJECTIVES

Ureterocele is a sac-like dilatation of terminal ureter. Precise anatomic delineation is of utmost importance to proceed with the surgical plan, particularly in the ectopic subtype. However, the level of ureterocele extension is not always elucidated by the existing imaging modalities and even by conventional cystoscopy, which is considered as the gold standard for evaluation of ureterocele. This study aims to evaluate the accuracy of three-dimensional virtual sonographic cystoscopy (VSC) in the characterization of ureterocele in duplex collecting systems.

METHODS

Sixteen children with a mean age of 5.1 (standard deviation 1.96) years with transabdominal ultrasonography-proven duplex system and ureterocele were included. They underwent VSC by a single pediatric radiologist. All of them subsequently had conventional cystoscopy, and the results were compared in terms of ureterocele features including anatomy, number, size, location, and extension.

RESULTS

Three-dimensional VSC was well tolerated in all cases without any complication. Image quality was suboptimal in 2 of 16 patients. Out of the remaining 14 cases, VSC had a high accuracy in characterization of the ureterocele features (93%). Only the extension of one ureterocele was not precisely detected by VSC.

CONCLUSIONS

The results of this study suggest three-dimensional sonography as a promising noninvasive diagnostic modality in the evaluation of ectopic ureterocele in children.

Computer-Aided tumor diagnosis in 3-D breast elastography

BACKGROUND AND OBJECTIVE

Breast cancer is the major cause of cancer-related mortality in women. However, the death rate can be effectively decreased if the breast cancer can be detected early and treated appropriately. In recent years, many studies have indicated that the elastography has the better diagnosis performance than conventional ultrasound (US).

METHOD

In this study, the 3-D tumor contour is obtained by using the proposed segmentation methods and then the features containing texture information, shape information, ellipsoid fitting information are extracted respectively by using the segmented 3-D tumor contour and B-mode images, and the features containing elasticity information are calculated using the same contour and elastographic images.

RESULTS

In this experiment, totally 40 biopsy-proved lesions containing 20 benign tumors and 20 malignant tumors are used to evaluate the proposed computer-aided diagnosis (CAD) system. From the experimental results, the combination of shape, ellipsoid fitting and elastographic features has the best performance with accuracy 90.50% (36/40), sensitivity 85.00% (17/20), specificity 95.00% (19/20), and the area under the ROC curve Az 0.987.

CONCLUSION

The result shows that tumors can be diagnosed more precisely by using the elastography images.

Three-dimensional Ultrasound Elasticity Imaging on an Automated Breast Volume Scanning System

Ultrasound elasticity imaging has demonstrated utility in breast imaging, but it is typically performed with handheld transducers and two-dimensional imaging. Two-dimensional (2D) elastography images tissue stiffness of only a plane and hence suffers from errors due to out-of-plane motion, whereas three-dimensional (3D) data acquisition and motion tracking can be used to track out-of-plane motion that is lost in 2D elastography systems. A commercially available automated breast volume scanning system that acquires 3D ultrasound data with precisely controlled elevational movement of the 1D array ultrasound transducer was employed in this study. A hybrid guided 3D motion-tracking algorithm was developed that first estimated the displacements in one plane using a modified quality-guided search method, and then performed an elevational guided-search for displacement estimation in adjacent planes. To assess the performance of the method, 3D radiofrequency echo data were acquired with this system from a phantom and from an in vivo human breast. For both experiments, the axial displacement fields were smooth and high cross-correlation coefficients were obtained in most of the tracking region. The motion-tracking performance of the new method was compared with a correlation-based exhaustive-search method. For all motion-tracking volume pairs, the average motion-compensated cross-correlation values obtained by the guided-search motion-tracking method were equivalent to those by the exhaustive-search method, and the computation time was about a factor of 10 lesser. Therefore, the proposed 3D ultrasound elasticity imaging method was a more efficient approach to produce a high quality of 3D ultrasound strain image.

Three-dimensional versus two-dimensional shear-wave elastography: Associations of mean elasticity values with prognostic factors and tumor subtypes of breast cancer

PURPOSE

To explore associations between prognostic factors and subtypes of invasive breast cancer (IBC) and elasticity values using three-dimensional (3D) and two-dimensional (2D) shear-wave elastography (SWE).

MATERIALS AND METHODS

Mean elasticity values (kPa) of 121 IBCs were measured using both 3D and 2D SWE. Associations between these values and prognostic factors and subtypes were analyzed using linear regression model.

RESULTS

In both 3D and 2D SWE, larger size and presence of lymphovascular invasion were independent factors influencing higher mean elasticity on multivariate analyses (all p values<0.05).

CONCLUSIONS

Using either 3D or 2D SWE, higher mean elasticity values are associated with poor prognostic factors of IBC.

Therapeutic response assessment using 3D ultrasound for hepatic metastasis from colorectal cancer: Application of a personalized, 3D-printed tumor model using CT images

Background & aims

To evaluate accuracy and reliability of three-dimensional ultrasound (3D US) for response evaluation of hepatic metastasis from colorectal cancer (CRC) using a personalized 3D-printed tumor model.

Methods

Twenty patients with liver metastasis from CRC who underwent baseline and after chemotherapy CT, were retrospectively included. Personalized 3D-printed tumor models using CT were fabricated. Two radiologists measured volume of each 3D printing model using 3D US. With CT as a reference, we compared difference between CT and US tumor volume. The response evaluation was based on Response Evaluation Criteria in Solid Tumors (RECIST) criteria.

Results

3D US tumor volume showed no significant difference from CT volume (7.18 ± 5.44 mL, 8.31 ± 6.32 mL vs 7.42 ± 5.76 mL in CT, p>0.05). 3D US provided a high correlation coefficient with CT (r = 0.953, r = 0.97) as well as a high inter-observer intraclass correlation (0.978; 0.958–0.988). Regarding response, 3D US was in agreement with CT in 17 and 18 out of 20 patients for observer 1 and 2 with excellent agreement (κ = 0.961).

Conclusions

3D US tumor volume using a personalized 3D-printed model is an accurate and reliable method for the response evaluation in comparison with CT tumor volume.

Comparison between 3-dimensional cranial ultrasonography and conventional 2-dimensional cranial ultrasonography in neonates: impact on reinterpretation

Purpose

The aim of this study was to evaluate impact of 3-dimensional cranial ultrasonography (3DUS) on reinterpretation of cranial ultrasonography images in neonates in comparison with 2-dimensional cranial ultrasonography (2DUS).

Methods

We retrospectively enrolled 50 young infants who simultaneously underwent both 2DUS and 3DUS scanning from February to March 2015. Two pediatric radiologists independently reviewed both scans for overall image quality on a 5-point scale. Five features were evaluated in both scans: the presence of germinal matrix hemorrhage (GMH), intraventricular hemorrhage (IVH), ventriculomegaly (VM), abnormality of periventricular echogenicity (PVE), and focal parenchymal lesions (FL). The concordance rate between the two scanning modes was calculated. The confidence level for each finding on a 3-point scale and the scanning time were compared between the two scanning modes. Interobserver agreement was evaluated using kappa statistics.

Results

Both scans demonstrated similar overall image quality in terms of reinterpretation (mean scores for 2DUS and 3DUS, 4.0±0.5 and 4.0±0.7 in reviewer 1, 3.9±0.6 and 4.0±0.8 in reviewer 2, respectively). GMH, IVH, VM, and FL showed perfect concordance, while PVE showed a concordance rate of 91.4% between the two modes by both reviewers. 3DUS was associated with a higher diagnostic confidence in the evaluation of GMH, IVH, and FL than 2DUS (P<0.05) for both reviewers. For PVE, 3DUS received a significantly higher confidence score than 2DUS from one of the reviewers. The mean scanning time for 2DUS and 3DUS was 92.75 seconds and 36 seconds, respectively. Interobserver agreement for qualitative scoring was almost perfect.

Conclusion

In reinterpretation, 3DUS showed very high concordance with 2DUS and a similar image quality. 3DUS also increased diagnostic confidence for several image findings and significantly decreased scan time.

New Dimensions in Renal Transplant Sonography: Applications of 3-Dimensional Ultrasound

BACKGROUND

The aim of this study is to demonstrate the usefulness of adding 3-dimensional (3D) ultrasound in evaluation of renal transplant vasculature compared to 2-dimensional (2D) Duplex ultrasound.

METHODS

One hundred thirteen consecutive renal transplant 2D and 3D ultrasound examinations were performed and retrospectively reviewed by 2 board-certified radiologists and a radiology resident individually; each reviewed 2D and then 3D images, including color and spectral Doppler. They recorded ability to visualize the surgical anastomosis and rated visualization on a subjective scale. Interobserver agreement was evaluated. Variant anastomosis anatomy was recorded. Tortuosity or stenosis was evaluated if localized Doppler velocity elevation was present.

RESULTS

The reviewers directly visualized the anastomosis more often with 3D ultrasound ((Equation is included in full-text article.)=97.5%) compared with 2D ((Equation is included in full-text article.)=54.5%) [difference in means (DM) = 43% (95% confidence interval (CI) = 36%-50%) (P < 0.001)]. The reviewers visualized the anastomosis more clearly with 3D ultrasound (P < 0.001) [difference in medians = 0.5, 1.0, and 1.0, (95% CI = 0.5-1.0, 0.5-1.0, and 1.0-1.5)]. Detection of variant anatomy improved with 3D ultrasound by 2 reviewers [DM = 7.1% and 8.9% (95% CI = 1%-13% and 4%-14%, respectively) (P < 0.05)]. There was high interobserver agreement [(Equation is included in full-text article.)= 95.3%, (95% CI = 91.9%-98.7%) regarding anastomosis visualization among reviewers with wide-ranging experience.

CONCLUSIONS

Direct visualization of the entire anastomosis was improved with 3D ultrasound. Three-dimensional evaluation improved detection of anatomic variants and identified tortuosity as the likely cause of borderline localized elevation in Doppler velocity. The data added by 3D ultrasound may obviate confirmatory testing with magnetic resonance angiography or computed tomographic angiography after equivocal 2D ultrasound results.

A New Reliable Method for Evaluating Gallbladder Dynamics: The 3-Dimensional Sonographic Examination

OBJECTIVES

The purpose of this study was to compare conventional 2-dimensional (2D) B-mode sonography with 3-dimensional (3D) sonography for assessing gallbladder volume and contractility.

METHODS

Gallbladder volume and contractility were evaluated in 32 healthy volunteers after fasting and abstinence from smoking for 8 hours and after a standardized balanced liquid meal. The gallbladder was evaluated with 2D sonography (with the use of the ellipsoid method) and with 3D sonography using a volumetric matrix probe. Both measurements were made by an operator who was skilled in sonography and an unskilled operator. The group of volunteers was subdivided into 2 subgroups including 16 participants, which represented the "2 moments" of acquisition by the techniques, particularly for the unskilled operator.

RESULTS

The postprandial volumes obtained with 3D sonography were significantly lower in comparison to the volumes obtained with 2D sonography (P= .013), and there was a significant difference between the measurements made by the skilled and unskilled operators only for 2D sonography (P< .001), whereas between the 2 moments of acquisition by the 3D technique, there was no significant difference. The reproducibility of the technique for evaluation of gallbladder volumes was higher for 3D sonography than 2D sonography, particularly for the postprandial evaluation.

CONCLUSIONS

The new 3D sonographic method using a volumetric matrix probe is a simple, reliable, and more reproducible technique than conventional 2D sonography, even if performed by an unskilled operator, and it allows a reliable stimulation test for a gallbladder dynamic study.

Off-site evaluation of three-dimensional ultrasound for the diagnosis of thyroid nodules: comparison with two-dimensional ultrasound

OBJECTIVES

We compared the diagnostic performance of off-site evaluation between prospectively obtained 3D and 2D ultrasound for thyroid nodules.

METHODS

3D and 2D ultrasonographies were preoperatively obtained from 85 consecutive patients (mean age, 51 years; age range, 28-83 years) who were referred for a total thyroidectomy. Three radiologists independently evaluated 3D and 2D images of 91 pathologically confirmed thyroid nodules (30 benign and 61 malignant nodules) for nodule characterization. Diagnostic performance, interobserver agreement and time for scanning were compared between 3D and 2D.

RESULTS

3D had significantly higher sensitivities than 2D for predicting malignancy (78.7 % vs. 61.2 %, P < 0.01) and extrathyroidal extension (66.7 % vs. 46.4 %, P = 0.03) in malignancy. In terms of specificities, there were no statistically significant differences between 2D and 3D for predicting malignancy (78.4 % vs. 74.8 %, P = 1.00) and extrathyroidal extension (63.6 % vs. 57.6 %, P = 0.46). With respect to interobserver agreement, 3D showed moderate agreement (κ = 0.53) for predicting extrathyroidal extension in malignancy compared with 2D ultrasound, which showed fair agreement (κ = 0.37). 3D saved time (30 ± 56.52 s) for scanning compared with 2D.

CONCLUSION

For off-site evaluation, 3D US is more useful for diagnosis of thyroid nodules than 2D US.

KEY POINTS

• 3D had higher sensitivity than 2D for predicting malignancy and extrathyroidal extension. • 3D showed better agreement for predicting extrathyroidal extension in malignancy than 2D. • 3D thyroid ultrasound saved time for scanning compared with 2D. • For off-site evaluation of thyroid nodules, 3D is more useful than 2D.

What's new in urologic ultrasound?

Ultrasound is an imaging technology that has evolved swiftly and has come a long way since its beginnings. It is a commonly used initial diagnostic imaging modality as it is rapid, effective, portable, relatively inexpensive, and causes no harm to human health. In the last few decades, there have been significant technological improvements in the equipment as well as the development of contrast agents that allowed ultrasound to be even more widely adopted for urologic imaging. Ultrasound is an excellent guidance tool for an array of urologic interventional procedures and also has therapeutic application in the form of high-intensity focused ultrasound (HIFU) for tumor ablation. This article focuses on the recent advances in ultrasound technology and its emerging clinical applications in urology.

Characteristics of fetuses evaluated due to suspected anencephaly: a population-based cohort study in southern Brazil

CONTEXT AND OBJECTIVE

Anencephaly is considered to be the most common type of neural tube defect. Our aim was to assess the clinical and gestational features of a cohort of fetuses with suspected anencephaly.

DESIGN AND SETTING

Population-based retrospective cohort study in a referral hospital in southern Brazil.

METHODS

The sample consisted of fetuses referred due to suspected anencephaly, to the Fetal Medicine Service of Hospital Materno Infantil Presidente Vargas, between January 2005 and September 2013. Clinical, radiological, pathological and survival data were gathered.

RESULTS

Our sample was composed of 29 fetuses. The diagnosis of suspected anencephaly was made on average at 21.3 weeks of gestation. Seven fetuses had malformations that affected other organs, and these included oral clefts (n = 4) and congenital heart defects (n = 2). In 16 cases, there was termination of pregnancy (n = 12) or intrauterine death (n = 4). Regarding those who were born alive (n = 13), all of them died in the first week of life. After postnatal evaluation, the diagnosis of anencephaly was confirmed in 22 cases (75.9%). Other conditions included amniotic band disruption complex (6.9%), microhydranencephaly (6.9%), merocrania (3.4%) and holoprosencephaly (3.4%).

CONCLUSIONS

Different conditions involving the cranial vault may be confused with anencephaly, as seen in our sample. However, these conditions also seem to have a poor prognosis. It seems that folic acid supplementation is not being properly performed.

Estimation of uterine volume: A comparison between Viewpoint and 3D ultrasound estimation in women undergoing laparoscopic hysterectomy

Objectives: To assess the three‐dimensional (3D) tool, Virtual Organ Computed‐aided AnaLysis™ (VOCAL) in the calculation of pre‐operative uterine volume and to correlate the measurements with those obtained with Viewpoint, using uterine dry weight (UDW) as the gold standard.

Methods: Prospective observational study of women consented for a laparoscopic hysterectomy (LH) at Nepean Hospital between October 2008 and November 2011. All women underwent detailed transvaginal scan (TVS) at the pre‐operative assessment. Two‐dimensional (D) images of the uterus were obtained both in the mid‐sagittal and transverse planes. 3D volumetric acquisitions were also obtained for each uterus in the mid‐sagittal plane. 2D measurements of the uterus in millimetres (Anterio‐Posterior, longitudinal and transverse) were recorded in Viewpoint software package (GE Healthcare ViewPoint, Germany); which then generated an estimated uterine volume (ml) using the ellipsoid formula. The 3D uterine volumetric datasets were reviewed using SonoView Pro and uterine volumes were estimated with off‐line processing using VOCAL™. The gold standard for comparison was UDW in grams (g), measured by the histopathologist at the time of analysis of the LH specimens. The relationship between the estimated uterine volumes and actual UDW was evaluated using correlation analysis. P‐values were calculated to ascertain the significance of these findings; P values &< 0.05 represented statistical significance.

Results: 76 women underwent LH during the study period. Complete data were available in 96% (74/76) of cases. The mean age of the women was 43.7 years and 92% were multiparous. The mean Viewpoint uterine volume was 283 ml, the mean VOCAL™ uterine volume was 249 ml and the mean UDW was 295 g. There was a significant correlation between UDW and estimated uterine volumes both for Viewpoint (R = 0.83, P < 0.001) and VOCAL™ (R = 0.97, P < 0.001), respectively. Viewpoint systematically overestimated weight by 43.1 g, whereas VOCAL™ underestimated by an average of 42.4 g, and this difference was statistically significant (P < 0.001). In terms of absolute values, the mean prediction error for VOCAL™ was −18.0 g and for Viewpoint it was 27.6 g (P &< 0.0001). Conclusion: VOCAL™ was found to be significantly more accurate than Viewpoint in the estimation of uterine volumes, and it was better correlated with UDW.

Combination of 2- and 3-dimensional contrast-enhanced transvaginal sonography for diagnosis of small adnexal masses

OBJECTIVES

The purpose of this study was to evaluate the efficacy of the combination of 2-dimensional (2D) and 3-dimensional (3D) contrast-enhanced sonography in discriminating between benign and malignant small adnexal masses.

METHODS

Selected patients were evaluated with both 2D and 3D contrast-enhanced sonography after conventional sonography before undergoing any surgery. Time-intensity curves for 2D contrast-enhanced sonography were constructed by using contrast-enhanced sonographic software. A vascular perfusion characteristic analysis was achieved by 2D and 3D contrast-enhanced sonography. Results were finally verified by surgery.

RESULTS

Forty-seven cases of benign and 10 cases of malignant small adnexal masses were discovered. Significant differences in perfusion patterns, time-intensity curve shapes for 2D contrast-enhanced sonography, grayscale contrast-enhanced sonography, and blood flow imaging on 3D contrast-enhanced sonography were observed between benign and malignant masses (P< .05). Two-dimensional contrast-enhanced sonography, 3D contrast-enhanced sonography, parallel combination of 2D and 3D contrast-enhanced sonography, and serial combination of 2D and 3D contrast-enhanced sonography all reached diagnostic sensitivity of 100% for discriminating benign from malignant masses, whereas specificity values were 61.7%, 63.8%, 68.1%, and 57.4%, respectively. Areas under the receiver operating characteristic curves were 0.809, 0.819, 0.840, and 0.787.

CONCLUSIONS

Two-dimensional contrast-enhanced sonography is of high value in distinguishing malignant from benign small adnexal masses; 3D contrast-enhanced sonography provides richer and more useful information for evaluation of these masses. Diagnostic sensitivity of 100% can be achieved when using a serial combination of 2D and 3D contrast-enhanced sonography, although specificity needs further improvement.

The potential of transabdominal 3D color doppler ultrasonography for diagnosis of gastric varices

GOALS/BACKGROUND

To examine the potential of transabdominal 3-dimensional (3D) color Doppler ultrasonography (3D-US) as a noninvasive tool to characterize gastric varices.

STUDY

This was a prospective study in which endoscopy was performed on 107 patients with chronic liver disease. Among these patients, 70 (42 males, 28 females) had gastric varices (46 fundal varices, 24 cardia varices; 30 small, 28 medium, and 12 large), and the 37 patients (25 males, 12 females) without gastric varices served as controls. The 3D-US data and endoscopic findings were compared with respect to grade, location, and similarity of varices.

RESULTS

The sensitivity and specificity of the 3D-US technique to detect gastric varices were 88.6% (62/70) and 100% (37/37), respectively. Although all fundal varices appeared adjacent to the posterior gastric wall, cardia varices were detected separately from the wall with a mean distance of 21.2 mm. The vascular volumes (mL) were 0.84±0.71 in small varices, 5.52±3.81 in medium varices, and 10.9±6.3 in large varices, with significant differences between different grades. The best cutoff value to detect medium-grade/large-grade gastric varices was 2.0 mL, with 83.3% sensitivity and 95.8% specificity. Seventy-nine percent (55/70) of patients showed partial resemblance or better between the 3D images and the endoscopic findings with good interreviewer agreement.

CONCLUSIONS

3D-US can quantitatively characterize gastric varices noninvasively in terms of grade, location, and appearance. This approach has the potential to improve objectivity and reduce invasiveness in the management of gastric varices.

Calibration for position tracking of swept motor 3-D ultrasound

Tracking the position and orientation of a 3-D ultrasound transducer has many clinical applications. Tracking requires calibration to find the transformation between the tracking sensor and the ultrasound coordinates. Typically the set of image slice data are scan converted to a Cartesian volume using assumed motor geometry and a single transformation to the sensor. We propose, instead, the calibration of individual slices using a 2-D calibration technique. A best fit to a subset of slices is performed to decrease data collection time compared with that for calibration of all slices, and to reduce the influence of random errors in individual calibrations. We compare our technique with four scan conversion-based techniques: 2-D N-wire on the center slice, N-wire using a 3-D volume, N-wire using a 3-D volume including the edge points and a new closed-form planar method using a 3-D volume. The proposed multi-slice technique produced the smallest point reconstruction error (0.82 mm using a tracked stylus).

Preoperative assessment of extrathyroidal extension of papillary thyroid carcinoma: comparison of 2- and 3-dimensional sonography

OBJECTIVES

The purpose of this study was to evaluate the diagnostic performance and interobserver agreement of 2-dimensional (2D) and 3-dimensional (3D) sonography for evaluating extrathyroidal extension of papillary thyroid carcinoma.

METHODS

A total of 79 papillary thyroid carcinomas in 79 patients who underwent both 2D and 3D sonography for preoperative staging of papillary thyroid carcinoma were included. When the lesion was abutting on the thyroid capsule on 2D sonography, 3D sonography was performed. Three radiologists reviewed 3 data sets: 2D sonography, 3D sonography, and a combined set of both for tumor staging. The diagnostic performance, including sensitivity, specificity, positive predictive value, negative predictive value, and accuracy, for extrathyroidal extension was analyzed. Interobserver agreement of the 3 radiologists was assessed with κ values.

RESULTS

The overall accuracy rates for 2D sonography, 3D sonography, and the combined set in predicting extrathyroidal extension were 60.8%, 66.2%, and 67.9%, respectively. The accuracy of the combined set was significantly higher than that of 2D sonography (P = .016). The interobserver agreement of the 3 reviewers was fair (κ = 0.33) for 2D sonography and moderate for 3D sonography (κ = 0.46) and the combined set (κ = 0.49).

CONCLUSIONS

Adding 3D sonography to 2D sonography could improve the accuracy and interobserver agreement for predicting extrathyroidal extension of papillary thyroid carcinoma.

Three-dimensional sonography in the evaluation of primary hyperparathyroidism

Three-dimensional sonography is useful in the preoperative evaluation of patients with primary hyperparathyroidism. In this pictorial essay, we review the characteristic spectrum of grayscale and Doppler appearances of parathyroid glands on 2-dimensional sonography and demonstrate the additional benefits of 3-dimensional scanning.

Comparison between different imaging techniques in the evaluation of malignant breast lesions: can 3D ultrasound be useful?

PURPOSE

This study was done to assess the feasibility of three-dimensional ultrasonography (3D-US) for volume calculation of solid breast lesions.

MATERIALS AND METHODS

The volumes of 36 malignant lesions were measured using conventional 2D-US, 3D-US and magnetic resonance imaging (MRI) and compared with that obtained with histology (standard of reference). With 2D Ultrasouns, volume was estimated by measuring three diameters and calculating volume with the mathematical formula for spheres. With 3D-US, stored images were retrieved and boundaries of masses were manually outlined; volume calculation was performed with VOCAL software. For MRI, volume measurements were obtained with special software for 3D reconstructions, after each lesion had been manually outlined. Histology measured the three main diameters and the volume was estimated using the mathematical formula for spheres. Interclass correlation coefficient (ICC) and Bland-Altman plots were used to assess agreement between the volumes measured.

RESULTS

ICC indicated that a good level of concordance was identified between 3D-US and histology (0.79). According to the Bland-Altman analysis, limits of agreement of mean differences of the volumes measured with the three imaging modalities were comparable with histology: -2 ÷ 1.5 cm(3) for 3D-US; -2.3 ÷ 1.3 cm(3) for 2D-US and -2.2 ÷ 1.6 cm(3) for MRI.

CONCLUSIONS

3D-US is a reliable method for the volumetric assessment of breast lesions. 3D-US is able to provide valuable information for the preoperative evaluation of lesions.

Value of near-isovoxel ultrasound for evaluation of ductal communications with pancreatic cystic lesions: correlation with magnetic resonance cholangiopancreatography

The aim of this study was to determine the value of near-isovoxel ultrasound (ISUS) using xMATRIX technology in assessment of ductal communications with pancreatic cystic lesions. Twenty patients with pancreatic cystic lesions (n = 21) on magnetic resonance cholangiopancreatography (MRCP), underwent 2-D ultrasound (US) and subsequent ISUS using a matrix probe. Two observers assessed the presence of ductal communications with pancreatic cystic lesions for all MRCP, 2-D US, and ISUS images with multi-planar reformation, using a 5-point confidence scale. Weighted-κ statistics and intra-class correlation coefficients were calculated. Inter-observer agreement for MRCP, 2-D US and ISUS was moderate, fair and moderate (0.475, 0.222 and 0.472), respectively. The intra-class correlation coefficients between ISUS and MRCP was higher than that between 2-D US and MRCP (0.8706 vs. 0.5353, observer 1; 0.7206 vs. 0.4818, observer 2, respectively). Correlation and inter-observer agreement were better with MRCP than with 2-D US. We conclude that ISUS may be useful in evaluating ductal communications with pancreatic cystic lesions.

[Modern imaging of kidney tumors]

If a renal mass is suspected on clinical examination or ultrasound the finding has to be confirmed by cross-sectional imaging. Methods that are used include multidetector-row computed tomography (MDCT) and magnetic resonance imaging (MRI). Also contrast-enhanced ultrasound has been successfully implemented in renal imaging and now plays a major role in the differentiation of benign from malignant renal masses. In expert hands it can be used to show very faint vascularization and subtle enhancement. The MDCT technique benefits from the recently introduced dual energy technology that allows superior characterization of renal masses in a single-phase examination, thereby greatly reducing radiation exposure. For young patients and persons allergic to iodine MRI should be used and it provides excellent soft tissue contrast and visualizes contrast enhancement kinetics in multiphase examinations.This article aims at giving a comprehensive overview of these different imaging modalities, their clinical indications and contraindications, as well as a description of imaging findings of various renal masses.

Three-dimensional sonography for diagnosis of rectovaginal septum endometriosis: interobserver agreement

OBJECTIVES

The aim of this study was to evaluate the interobserver agreement for diagnosis of deep endometriosis of the rectovaginal septum using introital 3-dimensional (3D) sonography.

METHODS

Two experienced observers (observers A and B) performed a retrospective review of stored 3D sonographic volumes from a sample of 84 consecutive patients with a clinical suspicion of endometriosis. Each observer, independently and blinded to each other, evaluated the presence or absence of involvement of the rectovaginal septum. When no lesion was seen, the observers were asked to judge whether the acquisition of the volume was suboptimal for interpretation or whether no lesion on the rectovaginal septum was detectable. One inadequate acquisition case was discarded; a total of 83 cases were evaluated. To calculate the performance of introital 3D sonography, 7 discordant cases were reviewed by a third observer. Interobserver agreement was assessed by calculating the κ index, and the sensitivity, specificity, positive predictive value, and negative predictive value for the 3 observers were also determined.

RESULTS

Interobserver agreement was 0.816 (95% confidence interval, 0.69-0.93), representing very good agreement. Sensitivity was 74.1%; specificity, 85.7%; positive predictive value, 71.4%; and negative predictive value, 87.3%.

CONCLUSIONS

Our results show that introital 3D sonography for diagnosis of deep endometriosis of the rectovaginal septum is reproducible, with very good interobserver agreement.

Differentiation of benign from malignant solid breast masses: comparison of two-dimensional and three-dimensional shear-wave elastography

OBJECTIVES

To prospectively compare the diagnostic performances of two-dimensional (2D) and three-dimensional (3D) shear-wave elastography (SWE) for differentiating benign from malignant breast masses.

METHODS

B-mode ultrasound and SWE were performed for 134 consecutive women with 144 breast masses before biopsy. Quantitative elasticity values (maximum and mean elasticity in the stiffest portion of mass, Emax and Emean; lesion-to-fat elasticity ratio, Erat) were measured with both 2D and 3D SWE. The area under the receiver operating characteristic curve (AUC), sensitivity and specificity of B-mode, 2D, 3D SWE and combined data of B-mode and SWE were compared.

RESULTS

Sixty-seven of the 144 breast masses (47 %) were malignant. Overall, higher elasticity values of 3D SWE than 2D SWE were noted for both benign and malignant masses. The AUC for 2D and 3D SWE were not significantly different: Emean, 0.938 vs 0.928; Emax, 0.939 vs 0.930; Erat, 0.907 vs 0.871. Either 2D or 3D SWE significantly improved the specificity of B-mode ultrasound from 29.9 % (23 of 77) up to 71.4 % (55 of 77) and 63.6 % (49 of 77) without a significant change in sensitivity.

CONCLUSION

Two-dimensional and 3D SWE performed equally in distinguishing benign from malignant masses and both techniques improved the specificity of B-mode ultrasound.

New paradigm for management of hepatocellular carcinoma by imaging

Based on recent clinical practice guidelines, imaging is largely replacing pathology as the preferred diagnostic method for determination of hepatocellular carcinoma (HCC). A variety of imaging modalities, including ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine, and angiography, are currently used to examine patients with chronic liver disease and suspected HCC. Advancements in imaging techniques such as perfusion imaging, diffusion imaging, and elastography along with the development of new contrast media will further improve the ability to detect and characterize HCC. Early diagnosis of HCC is essential for prompt treatment, which may in turn improve prognosis. Considering the process of hepatocarcinogenesis, it is important to evaluate sequential changes via imaging which would help to differentiate HCC from premalignant or benign lesions. Recent innovations including multiphasic examinations, high-resolution imaging, and the increased functional capabilities available with contrast-enhanced US, multidetector row CT, and MRI have raised the standards for HCC diagnosis. Although hemodynamic features of nodules in the cirrhotic liver remain the main diagnostic criterion, newly developed cellspecific contrast agents have shown great possibilities for improved HCC diagnosis and may overcome the diagnostic dilemma associated with small or borderline hepatocellular lesions. In the 20th century paradigm of medical imaging, radiological diagnosis was based on morphological characteristics, but in the 21st century, a paradigm shift to include biomedical, physiological, functional, and genetic imaging is needed. A multidisciplinary team approach is necessary to foster an integrated approach to HCC imaging. By developing and combining new imaging modalities, all phases of HCC patient care, including screening, diagnosis, treatment, and therapy, can be dramatically improved.

Detection of bladder cancer recurrence with real-time three-dimensional ultrasonography-based virtual cystoscopy

This prospective study evaluated the accuracy of grey-scale two-dimensional (2D) ultrasonography and real-time threedimensional (3D) ultrasonography-based virtual cystoscopy for detecting early recurrence of bladder cancer in previously treated patients (n = 40). Real-time 3D ultrasonography-based virtual cystoscopy images were compared with both 2D ultrasonography and interval conventional cystoscopy pathology results. Ultrasound examinations were performed before routine follow-up with conventional cystoscopy. Overall sensitivity for real-time 3D ultrasonography-based virtual cystoscopy was lower than for 2D ultrasonography, indicating it did not provide additional information. The results of combined (2D and 3D) ultrasonography and conventional cystoscopy differed significantly. Where lesions were detected with combined ultrasonography, the number of previous cystoscopies was lower and the tumour stage was significantly higher at initial diagnosis, compared with cases where no lesions were detected. The results suggest that ultrasonography before cystoscopy can be performed more frequently - or, if no lesions are detected by ultrasonography, the interval between cystoscopies can be prolonged - in patients at high risk of bladder cancer recurrence.

[Latest developments in ultrasound of the liver]

Abdominal ultrasound (US) is often the first-line imaging modality used to assess focal liver lesions. Due to various new gray-scaled US techniques, such as tissue harmonic imaging (THI), spatial compounding technique and speckle reduction technique, as well as contrast-enhanced techniques, abdominal ultrasound nowadays has great potential regarding detection and characterization of focal liver lesions. Furthermore, image fusion with computed tomography (CT), magnetic resonance imaging (MRI) and 3D ultrasound will most likely help to improve clinical management before and after interventional procedures. This article illustrates the principles and clinical impact of recently developed techniques in the field of ultrasound.