Improving the efficiency of gynecologic sonography with 3-dimensional volumes: a pilot study

How to do a 3D uterus ultrasound?

Three-dimensional (3D) ultrasound is an invaluable tool in the detection and evaluation of many uterine anomalies and improves upon the traditional approach of two-dimensional (2D) ultrasonography. We aim to describe an easy way of assessing the uterine coronal plane using the basic three-dimensional ultrasound in everyday gynecological practice.

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.

Is Hysteroscopy Better than Ultrasonography for Uterine Cavity Evaluation? An Evidence-Based and Patient-Oriented Approach

Evaluation of the uterine cavity is an important part of the gynecological check, especially in symptomatic women and, over the last few decades, a number of technical and technological advancements has allowed a superb investigation of this organ. Traditionally, transvaginal ultrasound (TVUS) has been the first-line diagnostic tool for evaluating uterine diseases, also considering that gynecologists are familiar with the technique since it is included in the basic training in obstetrics and gynecology. Nevertheless, to date “office hysteroscopy” received growing attention since the development of smaller-diameter hysteroscopes which has made it possible to easily perform the hysteroscopy in ambulatory settings, obviating the need for anesthesia and dilatation of the cervical canal.

According to our overview, none of the available methods for endometrial evaluation are ideal and each one has pros and cons. TVUS allows assessment of both the myometrium and the endometrium and typically offers greater patient comfort, but it has a higher false-negative rate in diagnosing focal intrauterine pathology. On the other hand, office hysteroscopy has the advantage of providing (most of the time) a real-time diagnosis avoiding anxiety, inconvenience and costs associated with follow-up appointments. The main advantage of the office hysteroscopy on the TVUS is the possibility to perform an operative phase if necessary during the examination itself. In fact, the modern smaller-diameter hysteroscopes have a working channel through which operative miniaturized instruments (mechanical instruments or bipolar electrodes) can be introduced, allowing the performance of target-eye biopsies and the “instant” treatment of most of uterine diseases in outpatient settings.

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.

The current status of three-dimensional ultrasonography in gynaecology

Ultrasonography (US) is the most recent cross-sectional imaging modality to acquire three-dimensional (3D) capabilities. The reconstruction of volumetric US data for multiplanar display took a significantly longer time to develop in comparison with computed tomography and magnetic resonance imaging. The current equipment for 3D-US is capable of producing high-resolution images in three different planes, including real-time surface-rendered images. The use of 3D-US in gynaecology was accelerated through the development of the endovaginal volume transducer, which allows the automated acquisition of volumetric US data. Although initially considered an adjunct to two-dimensional US, 3D-US is now the imaging modality of choice for the assessment of Müllerian duct anomalies and the location of intrauterine devices.

Comparison of 2- and 3-dimensional shoulder ultrasound to magnetic resonance imaging in a community hospital for the detection of supraspinatus rotator cuff tears with improved worktime room efficiency

PURPOSE

The purpose of this study was to evaluate whether 3-dimensional (3D) volumetric acquisition of shoulder ultrasound (US) data for supraspinatus rotator cuff tears is as sensitive when compared with conventional 2-dimensional (2D) US and routine magnetic resonance imaging (MRI), and whether there is improved workroom time efficiency when using the 3D technique compared with the 2D technique.

METHODS

In this prospective study, 39 shoulders underwent US and MRI examination of their rotator cuff to confirm the accuracy of both the 2D and 3D techniques. The difference in sensitivities was compared by using confidence interval analysis. The mean times required to obtain the 2D and 3D US data and to review the scans were compared by using a 1-tailed Wilcoxon test.

RESULTS

Sensitivity and specificity of 2D US in detecting supraspinatus full- and partial-thickness tears was 100% and 96%, and 80% and 100%, respectively, and similar values were obtained with 3D US at 100% and 100%, and 90% and 96.6%, respectively. Analysis of the confidence limits of the sensitivities showed no significant difference. The mean time (± SD) of the overall 2D examination of the shoulder, including interpretation was 10.02 ± 3.28 minutes, whereas, for the 3D examination, it was 7.08 ± 0.35 minutes. Comparison between the 2 cohorts when using a 1-tailed Wilcoxon test showed a statistically significant difference (P < .05).

CONCLUSION

3D US of the shoulder is as accurate as 2D US when compared with MRI for the diagnosis of full- and partial-thickness supraspinatus rotator cuff tears, and 3D US examination significantly reduced the time between the initial scan and the radiologist interpretation, ultimately improving workplace efficiency.

The role of 3-dimensional power Doppler imaging in the assessment of ovarian teratoma in pregnancy: a case report

Background. Conventional sonography is the primary imaging tool for these pregnant women who present with an ovarian teratoma. In some cases, however, sonography diagnosis is difficult. We report a case of ovarian teratoma during pregnancy diagnosed by three-dimensional Power Doppler. The cyst was removed via laparotomy without fetal or maternal complications. Three-dimensional ultrasound with multiplanar view can better discriminate a benign ovarian teratoma from complex ovarian lesions or malignant tumors. Its role is significant especially during pregnancy as it may assist in determining which patients are requiring surgery and which are not. The results of three-dimensional sonography and magnetic resonance (MR) were equal but the role of MR imaging is limited in early pregnancy. Conclusions. Three-dimensional technique is a reliable diagnostic modality for preoperative assessment of an ovarian teratoma as it can be performed during the first trimester of pregnancy.

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.

Can Hybrid Learning Theory Be Used to Teach Working Sonographers 3D Imaging Technology?

Three-dimensional sonography is being cited more frequently as a means of further evaluating the patient and better defining the pathological condition. One of the main limitations of fully implementing 3D imaging in the sonography department is the limited experience and limited time to educate working sonographers on how to fully understand and use this technology. Deliberate and planned educational activities designed to meet the educational needs of working sonographers may be a way to increase the clinical use of 3D technology in the clinical sonography department.

Incorporating 3D Multiplanar Reconstructed Images for Endovaginal Endometrial Assessment

A study was undertaken to evaluate the use of 3D multiplanar reconstructed (MPR) images to reduce the scan time for endovaginal studies, thereby potentially reducing sonographer strain and possibly improving patient workflow. The scope of the study was limited to evaluation of the endometrium. A group of 42 patients with dysfunctional uterine bleeding was selected for the study. After initial transabdominal examination on each patient, an endovaginal study of the endometrium was performed using 3D data collection; this was followed by a complete conventional 2D endovaginal scan. The scan times and endometrial measurements for 3D and 2D methods were compared. Staff members were interviewed for feedback on the experience and for future protocol recommendations.

An integrated circuit with transmit beamforming flip-chip bonded to a 2-D CMUT array for 3-D ultrasound imaging

State-of-the-art 3-D medical ultrasound imaging requires transmitting and receiving ultrasound using a 2-D array of ultrasound transducers with hundreds or thousands of elements. A tight combination of the transducer array with integrated circuitry eliminates bulky cables connecting the elements of the transducer array to a separate system of electronics. Furthermore, preamplifiers located close to the array can lead to improved receive sensitivity. A combined IC and transducer array can lead to a portable, high-performance, and inexpensive 3-D ultrasound imaging system. This paper presents an IC flip-chip bonded to a 16 x 16-element capacitive micromachined ultrasonic transducer (CMUT) array for 3-D ultrasound imaging. The IC includes a transmit beamformer that generates 25-V unipolar pulses with programmable focusing delays to 224 of the 256 transducer elements. One-shot circuits allow adjustment of the pulse widths for different ultrasound transducer center frequencies. For receiving reflected ultrasound signals, the IC uses the 32-elements along the array diagonals. The IC provides each receiving element with a low-noise 25-MHz-bandwidth transimpedance amplifier. Using a field-programmable gate array (FPGA) clocked at 100 MHz to operate the IC, the IC generated properly timed transmit pulses with 5-ns accuracy. With the IC flip-chip bonded to a CMUT array, we show that the IC can produce steered and focused ultrasound beams. We present 2-D and 3-D images of a wire phantom and 2-D orthogonal cross-sectional images (Bscans) of a latex heart phantom.

Evaluation of the accuracy and reliability of two 3-dimensional sonography methods in volume measurement of small structures: an in vitro phantom study

PURPOSE

To evaluate the accuracy and reliability of two 3-dimensional (3D) ultrasound imaging and measurement techniques in volume measurements using custom-made phantoms.

METHODS

A total of 20 phantoms with irregular-shaped test objects of known volume (2-9.7 ml) were constructed. The phantoms were scanned using an automated mechanical 3D sonography technique and a free-hand 3D sonography technique. The volumes of the test objects were measured with "parallel planes" and "rotating planes" techniques, respectively. The measured volumes were compared with the actual volumes of the test objects. To evaluate inter- and intraoperator measurement variability, the phantoms were scanned twice by 2 different operators.

RESULTS

Both the automated mechanical and the free-hand 3D sonography techniques were accurate and reliable. Automated mechanical 3D sonography with the parallel planes technique (accuracy, 81.5-83.4%; reproducibility, 91.1%; repeatability, 98.8-99.1%) was slightly more accurate and reliable than the free-hand rotating planes technique (accuracy, 74.7-84.2%; reproducibility, 88.4%; repeatability, 97.3-98%), but the differences were not statistically significant.

CONCLUSION

Both the automated and freehand volume measurement techniques evaluated in this study are accurate and reliable.

Detection of bladder tumors with 3-dimensional sonography and virtual sonographic cystoscopy

OBJECTIVE

Bladder tumors are among the most common types of malignant neoplasms of the urinary tract. The purpose of this study was to evaluate the potential value of 3-dimensional (3D) sonography and sonographic cystoscopy in detection of bladder tumors.

METHODS

Thirty-one patients with suspected or known bladder tumors were included this study. All patients underwent 3D sonography and conventional cystoscopy within 15 days. The number, size, location, and morphologic features of the lesions were evaluated on gray scale, 3D virtual, and multiplanar reconstruction images obtained from the patients. The results of 3D sonographic cystoscopy were compared with the findings from conventional cystoscopy, which was considered the reference standard.

RESULTS

Twenty-eight (90.3%) of 31 3D virtual sonographic cystoscopic studies had good or excellent image quality. Conventional cystoscopy revealed 47 lesions in 22 of 28 patients; 3D sonographic virtual cystoscopy showed 41 (87.2%) of 47 lesions. Three-dimensional virtual sonography alone had sensitivity of 96.2%, specificity of 70.6%, a positive predictive value of 93.9%, and a negative predictive value of 80% for tumor detection. The combination of gray scale sonography, multiplanar reconstruction, and 3D virtual sonography had sensitivity of 96.4%, specificity of 88.8%, a positive predictive value of 97.6%, and a negative predictive value of 84.2% for tumor detection.

CONCLUSIONS

Three-dimensional sonography is a promising alternative noninvasive technique for use in detection of bladder tumors, their localization, and perivesical spreading. The location, size, and morphologic features of the tumors shown on 3D sonography agreed well with the findings of conventional cystoscopy.

MRI and multiplanar 3D ultrasound compared in the prenatal assessment of enlarged posterior fossa

Our aim was to compare the diagnostic capabilities of the multiplanar mode of 3D ultrasound (3D US) and MRI in the assessment of a fetal enlarged cisterna magna. Two fetuses showing an enlarged posterior fossa by conventional two-dimensional ultrasound at 24 and 29 weeks of pregnancy were assessed using both diagnostic methods. One fetus was found to have Dandy-Walker syndrome malformation. In the other, the syndrome was ruled out using both methods. Our results suggest that multiplanar 3D US is able to achieve similar results as does MRI when observing the fetal brain.

Assessment of the third-trimester fetus using 3-dimensional volumes: a pilot study

PURPOSE

To examine whether the third-trimester fetus can be assessed sonographically using 3-dimensional (3D) volume data sets.

METHODS

Twenty-seven consecutive third-trimester fetuses were evaluated. Fetuses were scanned using 2-dimensional (2D) imaging followed by 5 3D volume acquisitions. The initial scan was interpreted and reported based on the 2D images. The 3D volume data sets were independently reviewed offline several weeks later by 2 sonologists. Parameters evaluated included fetal presentation, placental location, amniotic fluid volume, fetal biometry including a calculation of estimated fetal weight, and major fetal anatomic structures. The result of the interpretation via 3D reconstruction of the volume from each of the 2 sonologists was compared with the original 2D sonography report.

RESULTS

Fetal presentation, amniotic fluid volume, and placental location with respect to the cervix were correctly identified 100% of the time by each sonologist. The estimated fetal weight was within 10% of the 2D estimate 89% (95% CI, 0.71-0.98) of the time for sonologist A and 96% (95% CI, 0.81-0.99) of the time for sonologist B. The majority of major anatomic landmarks were adequately seen by both sonologists.

CONCLUSION

Offline review of 3D volume data sets is a reliable method for determining fetal presentation, amniotic fluid volume, placental location, and estimating fetal weight in the third trimester.

Renal sonography with 2-dimensional versus cine organ imaging: preliminary results

OBJECTIVE

This pilot study was undertaken to determine whether cine organ imaging (COI) of the entire kidney yields a quicker and equally diagnostic study compared with traditional 2-dimensional (2D) scanning.

METHODS

Fifty-seven adult patients referred for diagnostic renal sonography underwent 2D sonography followed by COI performed by a second sonographer, who was blinded to the results of the first examination. Images were interpreted blindly by 2 independent readers in 2 separate reading sessions divided into 2D or COI image sets for each patient. The acquisition time and interpretation time of each protocol were recorded. Images were scored for the percentage of kidney visualized and for the presence or absence of hydronephrosis, stones, cysts, and renal lesions (non-simple cysts and solid masses).

RESULTS

The average acquisition time decreased from 13.3 to 10.5 minutes between 2D and COI studies, respectively (P = .02). The average image interpretation time increased 37 seconds (P < .0001). A greater percentage of parenchymal visualization was achieved with COI versus 2D imaging. There was no significant difference in detection of renal abnormalities (hydronephrosis, stones, renal cysts, and masses) between the 2 modes, although the detection of cysts on COI was equal to or greater than that on 2D imaging on a per-patient basis.

CONCLUSIONS

Cine organ imaging decreased the acquisition time significantly while retaining and possibly improving diagnostic quality. The minimally increased interpretation time may be decreased in the future by fewer volume acquisitions per patient. Further investigations will be needed to assess the impact of color Doppler imaging in volumetric protocols as well as to compare renal lesion detection versus computed tomography and magnetic resonance imaging.

Impact of 3D Sonography on Workroom Time Efficiency

OBJECTIVE

The purpose of this study was to determine the effect on workroom time efficiency of the 3D sonographic technique compared with the 2D technique in examinations of the kidney, shoulder, small parts (thyroid, testes, Achilles tendon, other superficial structures), and female pelvic organs in a community hospital.

SUBJECTS AND METHODS

A random sample of 23 patients underwent consecutive 3D sonographic examinations on a single day. Another random sample of 40 patients underwent consecutive traditional 2D sonographic examinations the next day. Both cohorts included a mixture of patients who underwent shoulder, renal, small-parts, and pelvic scans. The 3D shoulder examinations were followed by direct examination by a radiologist using the traditional 2D technique to confirm the diagnostic accuracy of the 3D technique. The mean times that patients were in the sonography room for 2D and for 3D sonography were recorded and compared by use of a two-sample Student's t test.

RESULTS

The mean time per examination for the 3D cohort was 11.48 +/- 3.55 minutes (SD). The mean time per examination for the 2D cohort was 25.30 +/- 11.64 minutes. Results of a two-sample Student's t test showed the times for the two groups were statistically different (p < 0.001). No diagnoses made with 3D shoulder sonographic findings were changed when the shoulders were reevaluated directly by radiologists using conventional 2D sonography.

CONCLUSION

This study showed significantly better workroom time efficiency with use of 3D sonography than with traditional 2D sonography in pelvic, renal, small-parts, and shoulder examinations in a community hospital. These findings suggest that in the correct clinical setting, adopting 3D scanning protocols may greatly improve patient throughput.

Three and four-dimensional ultrasound in obstetrics and gynecology

PURPOSE OF REVIEW

Developments in ultrasound in general, but even more so in three-dimensional ultrasound, parallel the growth in computing power and speed of computer technology. It is not surprising, therefore, that three-dimensional ultrasound technology is constantly evolving at a fast pace. The purpose of this article is to provide enhanced diagnostic capabilities for the obstetrical and gynecologic provider.

RECENT FINDINGS

The most recent advances in three-dimensional ultrasound have to do with two main features. First, an increasingly fast acquisition speed, enabling quick sequences of fast moving organs such as the heart to be captured. Second, the increasing number of different display modalities, making understanding and analysis of normal anatomy and pathology easier for clinicians.

SUMMARY

This article highlights a selected number of clinical situations in which three-dimensional ultrasound meaningfully enhances the contribution of this fast evolving diagnostic imaging tool.