This review demonstrates the unique advantages of sonography in the oncologic setting. Although computed tomography, magnetic resonance imaging, and positron emission tomography–computed tomography are primary imaging modalities for evaluation of the oncologic patient, sonography is useful for evaluation of various conditions and clinical scenarios associated with cancer. The following article will illustrate the utility of sonography at a tertiary cancer center for diagnosis and problem solving.
cancer; general sonography; radiology; sonography
To evaluate the accuracy of sonographic classification of chorionicity in a large cohort of twins and investigate which factors may be associated with sonographic accuracy.
We conducted a secondary analysis of a randomized trial of preterm birth prevention in twins. Sonographic classification of chorionicity was compared with pathologic examination of the placenta. Maternal (age, body mass index, diabetes, and hypertension), obstetric (prior cesarean delivery, gestational age at the first sonographic examination, and antepartum bleeding), and sonographic (oligohydramnios, polyhydramnios, and twin-twin transfusion syndrome) factors were assessed for their possible association with accuracy.
A total of 545 twin sets in which chorionicity was classified by sonography before 20 weeks’ gestation were included; 455 were dichorionic and 90 were monochorionic based on pathologic examination. Sonography misclassified 35 of 545 twin pregnancies (6.4%): 18 of 455 dichorionic twins (4.0%) and 17 of 90 monochorionic twins (19.0%). The sensitivity and specificity of sonographic diagnosis of monochorionicity were 81.1% and 96.0%, respectively. In a multivariable analysis, pregnancies with initial sonographic examinations before 14 weeks’ gestation were less likely to have misclassified chorionicity than those with sonographic examinations at 15 to 20 weeks (odds ratio [OR], 0.47; 95% confidence interval [CI], 0.23–0.96). For each week increase in gestational age, the odds of misclassification rose by 10% (OR, 1.10; 95% CI, 1.01–1.2). In the multivariable analysis, maternal age, body mass index, parity, and prior cesarean delivery were not associated with sonographic accuracy.
Sonography before 20 weeks incorrectly classified chorionicity in 6.4% of twin gestations. Those with first sonographic examinations performed at earlier gestational ages had improved chorionicity diagnosis.
accuracy; chorionicity; obstetric ultrasound; sonography; twins
To estimate the efficiency of first-trimester uterine artery Doppler, A-disintegrin and metalloprotease 12 (ADAM12), pregnancy-associated plasma protein A (PAPP-A) and maternal characteristics in the prediction of pre-eclampsia.
This is a prospective cohort study of patients presenting for first-trimester aneuploidy screening between 11-14 weeks’ gestation. Maternal serum ADAM12 and PAPP-A levels were measured by immunoassay, and mean uterine artery Doppler pulsatility indices (PI) were calculated. Outcomes of interest included pre-eclampsia, early pre-eclampsia, defined as requiring delivery at <34 weeks’ gestation, and gestational hypertension. Logistic regression analysis was used to model the prediction of pre-eclampsia using ADAM12 multiples of the median (MoM), PAPP-A MoM, and uterine artery Doppler PI MoM, either individually or in combination. Sensitivity, specificity, and area under the receiver-operating characteristic curves (AUC) were used to compare the screening efficiency of the models using non-parametric U-statistics.
Of 578 patients with complete outcome data, there were 54 (9.3%) cases of preeclampsia and 13 (2.2%) cases of early pre-eclampsia. Median ADAM12 levels were significantly lower in patients who developed pre-eclampsia compared to those who did not. (0.81 v. 1.01 MoMs; p<0.04) For a fixed false positive rate (FPR) of 10%, ADAM12, PAPP-A, and uterine artery Doppler in combination with maternal characteristics identified 50%, 48%, and 52% of patients who developed pre-eclampsia, respectively. Combining these first-trimester parameters did not improve the predictive efficiency of the models.
First-trimester ADAM12, PAPP-A, and uterine artery Doppler are not sufficiently predictive of pre-eclampsia. Combinations of these parameters do not further improve their screening efficiency.
ADAM12; PAPP-A; placental dysfunction; pre-eclampsia; uterine artery Doppler
Volumetric contrast-enhanced ultrasound (VCEUS) imaging has the potential to monitor changes in renal perfusion following vascular injury.
VCEUS utilizes a series of planar image acquisitions, capturing the non-linear second harmonic signal from microbubble (MB) contrast agents flowing in the vasculature. Tissue perfusion parameters (peak intensity, IPK; time-to-peak intensity, TPK; wash-in rate, WIR; area under curve, AUC) were derived from time-intensity curve data collected during in vitro flow phantom studies and in vivo animal studies of healthy and injured kidney. For the flow phantom studies, either the concentration of MB contrast agent was held constant (10 µL/L) with varying volumetric flow rates (10, 20, and 30 mL/min) or the flow rate was held constant (30 mL/min) and the contrast agent concentration was varied (5, 10, and 20 µL/L). Animal studies were performed using either healthy rats or those that underwent renal ischemia-reperfusion injury. A series of renal studies were performed using healthy rats (N = 4) while the angle of the transducer was varied for each VCEUS image acquisition (reference or 0°, 45°, and 90°) to assess if repeated renal perfusion measures were isotropic and independent of transducer position. Blood serum biomarkers and immunohistology were used to confirm acute kidney injury.
Flow phantom results revealed a linear relationship between MB concentrations injected into the flow system and the IPK, WIR, and AUC perfusion measures (R2 > 0.56, P < 0.005). Further, there was a linear relationship between changes in volume flow rate and the TPK, WIR, and AUC metrics (R2 > 0.77, P < 0.005). No significant difference was found between the transducer angle during data acquisition and any of the derived renal perfusion measures (P > 0.60). After induction of renal ischemia-reperfusion injury in a rat animal model (N = 4), VCEUS imaging of the injured kidney revealed an initial reduction in renal perfusion when compared to control animals followed by a progressive recovery of vascular function.
Preliminary results are encouraging and VCEUS-based renal perfusion imaging may prove clinically feasible for detecting and monitoring acute kidney injury.
acute kidney injury; contrast-enhanced ultrasound; microbubbles; renal perfusion; volumetric imaging
Bedside ultrasonography in the diagnosis of pneumothorax has been well described in emergency and trauma medicine literature. Its role in detection of iatrogenic pneumothoraces has not been studied. We describe the performance of bedside ultrasonography in detection of procedure related pneumothoraces and highlight some limitations.
185 patients underwent thoracentesis (n=60), transbronchial biopsy (n=48), CT-guided lung biopsy (n=76), and CT-guided cryoablation of a lung mass (n=1). Bedside transthoracic ultrasound examination and post-procedure chest radiograph were performed in all patients. Patients in whom pleural surface was not well imaged with ultrasound were said to have a limited exam. Chest x-ray was the standard for diagnosing pneumothorax.
Chest x-ray detected pneumothorax in 8/185 patients (4.0%). Ultrasound diagnosed pneumothorax in seven of these patients. Sensitivity, specificity and diagnostic accuracy were 88%, 97% and 97%, respectively. Limited quality ultrasound examinations due to pre-existing lung disease was seen in 43/185 patients. The positive and negative likelihood ratios for patients with adequate scans were 55 and 0.17, respectively. Likelihood ratio for patients with limited quality scan was 1.08.
Bedside chest ultrasonography, in the presence of good quality scan, is a valuable tool in the evaluation of post procedure pneumothorax. Patients with preexisting lung disease in whom the quality of ultrasound examination is limited should be studied with a chest x-ray.
The purpose of this study was to provide clinical evidence of the use of contrast-enhanced sonography in detecting and quantifying changes in intraneural vascularity due to median mononeuropathy.
Five Macaca fascicularis monkeys were exposed to 20 weeks of repetitive work to increase their risk of developing median mononeuropathy. Contrast-enhanced sonograms were obtained in 30-second increments for 7 minutes while a contrast agent was being delivered. Data were collected immediately at the conclusion of the 20-week work exposure and then again during a recovery phase approximately 3 months after the completion of work. Quantitative analysis and trend graphs were used to analyze median nerve perfusion intensity. This study also compared the use of both manual counting of pixels and semiautomatic measurement using specialized software.
Based on the average data, maximum intensity values were identified as the best indicators of nerve hyperemia. Paired t tests demonstrated significantly higher maximum intensities in the working stage for 4 of the 5 subjects (P < .01).
This study provides preliminary evidence that (1) in a controlled exposure model, a change in intraneural vascularity of the median nerve between working and recovery can be observed; (2) this vascular change can be measured using an objective technique that quantifies the intensity of vascularity; and (3) contrast-enhanced sonography may improve the ability to reliably capture and measure low-flow microvascularity.
carpal tunnel syndrome; contrast-enhanced sonography; median mononeuropathy; musculoskeletal ultrasound
Ultrasound backscatter microscopy (UBM), or ultrasound biomicroscopy, is a noninvasive, label-free, and ionizing radiation–free technique allowing high-resolution 3-dimensional structural imaging. The goal of this study was to evaluate UBM for resolving anatomic features associated with squamous cell carcinoma of the oral cavity.
The study was conducted in a hamster buccal pouch model. A carcinogen was topically applied to cheeks of 14 golden Syrian hamsters. Six additional hamsters served as healthy controls. A high-frequency (41 MHz, 6-mm focal depth, lateral and axial resolutions of 65 and 37 μm, respectively) UBM system was used for scanning the oral cavity after 14 weeks of carcinogen application. Histologic analyses were conducted on scanned regions.
The histologic structure of buccal tissue and microvasculature networks could be visualized from the UBM images. Epithelial and mucosal hypertrophy and neoplastic changes were identified in animals subjected to the carcinogen. In animals with invasive squamous cell carcinoma, lesion development and destruction of the structural integrity of tissue layers were noted.
In this pilot study, UBM generated sufficient contrast for morphologic features associated with oral carcinoma compared to healthy tissue. This modality may present a practical technique for detection of oral neoplasms that is potentially translatable to humans.
biomicroscopy; high-frequency ultrasound; oral cancer; oral tissue characterization; squamous cell carcinoma; ultrasound backscatter microscopy
A major pathologic finding in patients with idiopathic carpal tunnel syndrome is noninflammatory fibrosis and thickening of the subsynovial connective tissue. The objective of this study was to determine the ability of sonography to depict this thickening by comparing subsynovial connective tissue thickness in patients with carpal tunnel syndrome and healthy control participants.
Longitudinal sonograms of the middle finger superficial flexor tendon and subsynovial connective tissue were obtained at 3 levels: at the wrist crease (proximal tunnel), at the hook of the hamate (mid tunnel), and at the distal edge of the transverse carpal ligament (distal tunnel). The thickness of the subsynovial connective tissue perpendicular to the direction of the tendon and the diameter of the flexor digitorum superficialis tendon at the same level were measured. Then, a thickness ratio was created.
At all 3 levels, the subsynovial connective tissue was thicker in patients than in controls (P < .0001) with a thickness ranging from 0.60 to 0.63 mm in patients and 0.46 to 0.50 mm in controls. The thickness ratio was significantly greater in patients at the hamate and distal levels (P = .018 and .013, respectively).
With this study, we have shown that it is possible to measure subsynovial connective tissue thickness with sonography, and the tissue is thicker in patients with carpal tunnel syndrome than in healthy controls.
carpal tunnel syndrome; sonography; subsynovial connective tissue; tendon
The aim of this study was to image both tendon and subsynovial connective tissue movement in patients with carpal tunnel syndrome and healthy control volunteers, using sonography with speckle tracking. To estimate accuracy of this tracking method, we used in vivo measurements during surgery to validate the motion estimated with sonography.
We recruited 22 healthy volunteers and 18 patients with carpal tunnel syndrome. Longitudinal sonograms of the middle finger flexor digitorum superficialis tendon and subsynovial connective tissue were obtained during finger flexion and extension. The images were analyzed with a speckle-tracking algorithm. The ratio of the sub-synovial connective tissue velocity to tendon velocity was calculated as the maximum velocity ratio, and the shear index, the ratio of tendon to subsynovial connective tissue motion, was calculated. For validation, we recorded flexor digitorum superficialis tendon motion during open carpal tunnel release.
The shear index was higher in patients than controls (P < .05), whereas the maximum velocity ratio in extension was lower in patients than controls (P < .05). We found good intraclass correlation coefficients (>0.08) for shear index and maximum velocity ratio measurements between speckle-tracking and in vivo measurements. Bland-Altman analyses showed that all measurements remained within the limits of agreement.
Speckle tracking is a potentially useful method to assess the biomechanics within the carpal tunnel and to distinguish between healthy individuals and patients with carpal tunnel syndrome. This method, however, needs to be further developed for clinical use, with the shear index and maximum velocity ratio as possible differentiating parameters between patients with carpal tunnel syndrome and healthy individuals.
carpal tunnel; motion; sonography; speckle tracking
To estimate the association between isolated mid-trimester short femur length (FL) and fetal growth restriction (FGR) as well as other adverse perinatal outcomes.
A retrospective cohort study of patients with singleton gestations presenting for ultrasound between 16-24 weeks’ gestation from 1990-2009. Cases of aneuploidy, skeletal dysplasia and major anomalies were excluded. Short FL was defined as FL<10th percentile for gestational age (GA). Short FL was considered isolated when both the estimated fetal weight and abdominal circumference were >10th percentile for GA. Isolated short FL<5th percentile was also evaluated. The primary outcome was FGR defined as birth weight <10th percentile. Secondary outcomes included pre-eclampsia and preterm birth (PTB) <37 weeks and <34 weeks. Univariable and multivariable logistic regression analyses were used to estimate the risk of these outcomes in fetuses with isolated short FL.
Of 73,884 patients, 569 (0.8%) had a fetus with a FL<10th percentile. Of these, 268 (47.1%) were isolated. 210 patients (0.3%) had a fetus with a FL<5th percentile, of which 34 (16.2%) were isolated. Both isolated short FL<10th percentile and <5th percentile were associated with an increased risk for FGR. (<10th percentile: aOR 3.4, 95% CI 2.4-4.6; <5th percentile: aOR 4.6, 95% CI 2.0-10.7). Isolated short FL<10th percentile and <5th percentile were also associated with an increased risk for PTB <37 weeks and <34 weeks. There was no significant association between isolated short FL and pre-eclampsia.
Isolated short FL on second-trimester ultrasound is associated with a greater than 3-fold increased risk for FGR as well as an increased risk for PTB. Serial growth assessment may be warranted in these cases.
short femur length; fetal growth restriction; pre-eclampsia; preterm birth
Burgeoning interest in reducing the morbidity and mortality associated with abdominal aortic aneurysms (AAAs) has led to experimental strategies to elucidate the disease process and attain pharmacologic regression using the apolipoprotein E−/− (ApoE−/−) mouse model of angiotensin-induced AAAs and in vivo sonography. However, the variability of in vivo sonographic measurements of the mouse aorta has not been established. Thus, our purpose was to determine quantitative estimates of the variability of in vivo sonographic measurements of the mouse aorta as a guide for the design and assessment of studies focused on regression of AAAs and related arterial diseases.
We used Bland-Altman, locally weighted scatterplot-smoothing regression, and resampling (bootstrapping) methods for variability analyses of multiple in vivo short- and long-axis sonographic measurements of ApoE−/− mouse aortas. We measured distinct aortic sites in vivo at the baseline and after angiotensin-induced AAAs and ex vivo using digital calipers.
We analyzed 236 data points from 10 male mice (14 weeks old; mean weight ± SD, 29.7 ± 1.6 g). Overall intramouse differences between short- and long-axis and in vivo and ex vivo measurements were 0.038 (95% confidence interval [CI], 0.031–0.046) and 0.085 (95% CI, 0.062–0.109) mm, respectively. Intermouse differences in short-axis measurements were 0.047 (95% CI, 0.042–0.053), 0.049 (95% CI, 0.044–0.055), and 0.039 (95% CI, 0.036-0.042) mm for infrarenal, suprarenal, and thoracic measurements, respectively; differences in long-axis measurements were 0.054 (95% CI, 0.044–0.064), 0.029 (95% CI, 0.024–0.034), and 0.046 (95% CI, 0.037–0.054) mm. Bland-Altman and locally weighted scatterplot-smoothing analyses showed excellent agreement between measures with no variation in discrepancies vis-à-vis the target measurement.
These data establish previously undefined estimates of measurement variability relevant for in vivo sonographic studies of AAA regression in a commonly studied mouse model.
abdominal aortic aneurysm; mouse model; sonography; variability
Applications of ultrasound in medicine for therapeutic purposes have been an accepted and beneficial use of ultrasonic biological effects for many years. Low power ultrasound of about 1 MHz frequency has been widely applied since the 1950s for physical therapy in conditions such as tendinitis or bursitis. In the 1980s, high pressure-amplitude shockwaves came into use for mechanically resolving kidney stones, and “lithotripsy” rapidly replaced surgery as the most frequent treatment choice. The use of ultrasonic energy for therapy continues to expand, and approved applications now include uterine fibroid ablation, cataract removal (phacoemulsification), surgical tissue cutting and hemostasis, transdermal drug delivery, and bone fracture healing, among others. Undesirable bioeffects can occur including burns for thermal-based therapies and significant hemorrhage for mechanical-based therapies (e. g. lithotripsy). In all these therapeutic applications for bioeffects of ultrasound, standardization, ultrasound dosimetry, benefits assurance and side-effects risk minimization must be carefully considered in order to insure an optimal benefit to risk ratio for the patient. Therapeutic ultrasound typically has well-defined benefits and risks, and therefore presents a tractable safety problem to the clinician. However, safety information can be scattered, confusing or subject to commercial conflict of interest. Of paramount importance for managing this problem is the communication of practical safety information by authoritative groups, such as the AIUM, to the medical ultrasound community. In this overview, the Bioeffects Committee outlines the wide range of therapeutic ultrasound methods, which are in clinical use or under study, and provides general guidance for assuring therapeutic ultrasound safety.
We compared trilinear interpolation to voxel nearest neighbor and distance-weighted algorithms for fast and accurate processing of true 3-dimensional ultrasound (3DUS) image volumes. In this study, the computational efficiency and interpolation accuracy of the 3 methods were compared on the basis of a simulated 3DUS image volume, 34 clinical 3DUS image volumes from 5 patients, and 2 experimental phantom image volumes. We show that trilinear interpolation improves interpolation accuracy over both the voxel nearest neighbor and distance-weighted algorithms yet achieves real-time computational performance that is comparable to the voxel nearest neighbor algrorithm (1–2 orders of magnitude faster than the distance-weighted algorithm) as well as the fastest pixel-based algorithms for processing tracked 2-dimensional ultrasound images (0.035 seconds per 2-dimesional cross-sectional image [76,800 pixels interpolated, or 0.46 ms/1000 pixels] and 1.05 seconds per full volume with a 1-mm3 voxel size [4.6 million voxels interpolated, or 0.23 ms/1000 voxels]). On the basis of these results, trilinear interpolation is recommended as a fast and accurate interpolation method for rectilinear sampling of 3DUS image acquisitions, which is required to facilitate subsequent processing and display during operating room procedures such as image-guided neurosurgery.
image-guided neurosurgery; interpolation; rasterization; volumetric 3-dimensional ultrasound
We have developed a blood flow measurement system using Doppler ultrasound flow sensors fabricated of thin and flexible piezoelectric-polymer films. These flow sensors can be wrapped around a blood vessel and accurately measure flow. The innovation that makes this flow sensor possible is the diffraction-grating transducer. A conventional transducer produces a sound beam perpendicular to its face; therefore, when placed on the wall of a blood vessel, the Doppler shift in the backscattered ultrasound from blood theoretically would be 0. The diffraction-grating transducer produces a beam at a known angle to its face; therefore, backscattered ultrasound from the vessel will contain a Doppler signal. Flow sensors were fabricated by spin coating a poly(vinylidene fluoride–trifluoroethylene) copolymer film onto a flexible substrate with patterned gold electrodes. Custom-designed battery-operated continuous wave Doppler electronics along with a laptop computer completed the system. A prototype flow sensor was evaluated experimentally by measuring blood flow in a flow phantom and the infrarenal aorta of an adult New Zealand White rabbit. The flow phantom experiment demonstrated that the error in average velocity and volume blood flow was less than 6% for 30 measurements taken over a 2.5-hour period. The peak blood velocity through the rabbit infrarenal aorta measured by the flow sensor was 118 cm/s, within 1.7% of the measurement obtained using a duplex ultrasound system. The flow sensor and electronics operated continuously during the course of the 5-hour experiment after the incision on the animal was closed.
diffraction-grating transducer; Doppler ultrasound; poly(vinylidene fluoride–trifluoroethylene); vascular surgery
Our objectives were to develop a new, efficient, and easy-to-administer approach to ultrasound elastography and assess its ability to provide quantitative characterization of viscoelastic properties of skeletal muscle in an outpatient clinical environment. We sought to show its validity and clinical utility in assessing myofascial trigger points, which are associated with myofascial pain syndrome.
Ultrasound imaging was performed while the muscle was externally vibrated at frequencies in the range of 60 to 200 Hz using a handheld vibrator. The spatial gradient of the vibration phase yielded the shear wave speed, which is related to the viscoelastic properties of tissue. The method was validated using a calibrated experimental phantom, the biceps brachii muscle in healthy volunteers (n = 6), and the upper trapezius muscle in symptomatic patients with axial neck pain (n = 13) and asymptomatic (pain-free) control participants (n = 9).
Using the experimental phantom, our method was able to quantitatively measure the shear moduli with error rates of less than 20%. The mean shear modulus ± SD in the normal biceps brachii measured 12.5 ± 3.4 kPa, within the range of published values using more sophisticated methods. Shear wave speeds in active myofascial trigger points and the surrounding muscle tissue were significantly higher than those in normal tissue at high frequency excitations (>100 Hz; P < .05).
Off-the-shelf office-based equipment can be used to quantitatively characterize skeletal muscle viscoelastic properties with estimates comparable to those using more sophisticated methods. Our preliminary results using this method indicate that patients with spontaneous neck pain and symptomatic myofascial trigger points have increased tissue heterogeneity at the trigger point site and the surrounding muscle tissue.
biomechanics; myofascial trigger points; shear wave elastography; ultrasound
Uterine abnormalities, such as leiomyomas, endometrial polyps, and adenomyosis, are often clinically associated with irregular uterine bleeding. These abnormalities can have similar B-mode characteristics but require different treatment. The objective of this study was to develop diagnostic techniques based on ultrasound strain imaging that would allow in vivo visualization and characterization of endometrial and myometrial uterine abnormalities, enabling physicians to improve diagnosis and treatment.
Ultrasound strain imaging was performed on 29 uteri removed via elective hysterectomy. An ultrasound system with a linear array transducer was used to obtain radio frequency echo data during manual freehand compressions of the tissue. Radio frequency data were post-processed with a 2-dimensional block-matching algorithm to generate strain images.
In the uteri involved in this study, there were 19 leiomyomas, 1 case of adenomyosis, and 3 endometrial polyps observed on strain imaging. Leiomyomas appeared stiffer than the surrounding normal myometrium in strain images and were characterized by a slipping artifact at their boundary. Endometrial polyps appeared softer than the normal surrounding myometrium. The average strain contrast in small leiomyomas (<1.5 cm) compared to the myometrium was 1.75 ± 1.14; the strain contrast was 2.50 ± 1.15 in large leiomyomas and 0.40 ± 0.05 in endometrial polyps. Leiomyoma strain contrast results were consistent with modulus contrast values from mechanical testing results.
Ultrasound strain imaging can differentiate between endometrial polyps and leiomyomas. More data are necessary to validate these results and to ascertain whether other uterine abnormalities can also be differentiated.
adenomyosis; elastography; endometrial polyps; leiomyomas; strain imaging; uterus
To correlate MR 2D measurements of lateral ventricular width and 3D measures of lateral ventricular and supratentorial parenchymal volumes to postnatal outcomes in fetuses with ventriculomegaly (VM).
307 fetuses (mean gestational age 26.0 weeks, range 15.7-39.4 weeks) had MR volumetry after referral for VM. Fetuses were grouped into those with (N=114) or without (N=193) other CNS anomalies. Pregnancy outcome and postnatal neurodevelopmental outcomes up to age 3 were obtained. A subgroup analysis was performed excluding fetuses with other CNS anomalies. Logistic regression analysis was performed to assess which measure was most predictive of outcome.
There were 50 terminations and 2 stillbirths. There were 255 live births. 75 were lost to follow-up. Among 180 liveborn infants with follow-up, 140 had an abnormal and 40 had normal outcome. Atrial diameter (p<0.0001), frontal horn diameter (p<0.0001), and ventricular volume (p=0.04) were each predictive of live-birth, with each having 92% specificity at 60% sensitivity. Among fetuses without other CNS anomalies, 180/193 (93%) pregnancies resulted in live deliveries, with atrial diameter (p<0.0001), frontal horn diameter (p=0.003), and ventricular volume (p=0.008) associated with live birth, and with atrial diameter having highest specificity of >99% at 60% sensitivity. Parenchymal volume was not associated with normal or abnormal outcome (either livebirth vs. demise or normal vs. abnormal neurodevelopmental outcome). Among live-borns, there was no age-adjusted threshold for any of the measures that reliably distinguished between normal and abnormal neurodevelopmental outcome.
Ventricular volume and diameter, but not parenchymal volume, correlate with live birth in fetuses with VM. However, once live-born, neither 2D nor 3D measurements can distinguish a fetus that will go on to have a normal outcome.
central nervous system; fetus; MRI; ventriculomegaly; volumetry; neurodevelopment
The purpose of this study was to document and analyze intraneural vascular flow within the median nerve using power and spectral Doppler sonography and to determine the relationship of this vascular flow with diagnosis of carpal tunnel syndrome based on electrodiagnostic testing.
Power and spectral Doppler sonograms in the median nerve were prospectively collected in 47 symptomatic and 44 asymptomatic subjects. Doppler studies were conducted with a 12-MHz linear transducer. Strict inclusion criteria were established for postexamination assessment of waveforms; routine quality assurance was completed; electrodiagnostic tests were conducted on the same day as sonographic measurements; and the skin temperature was controlled. Included waveforms were categorized by location and averaged by individual for comparative analysis to electrodiagnostic testing.
A total of 416 waveforms were collected, and 245 were retained for statistical analysis based on strict inclusion criteria. The mean spectral peak velocity among all waveforms was 4.42 (SD, 2.15) cm/s. At the level of the pisiform, the most consistent data point, mean peak systole, was 3.75 cm/s in symptomatic patients versus 4.26 cm/s in asymptomatic controls. Statistical trending showed an initial increase in the mean spectral peak velocity in symptomatic but diagnostically negative cases, with decreasing velocity as diagnostic categories progressed from mild to severe.
An inverse relationship may exist between intraneural vascular flow in the median nerve and an increasing severity of carpal tunnel syndrome based on nerve conduction results. Randomized controlled trials are needed to determine whether spectral Doppler sonography can provide an additive benefit for diagnosing the severity of carpal tunnel syndrome.
carpal tunnel syndrome; electrodiagnostics; median mononeuropathy; musculoskeletal sonography
In this article, we demonstrate the feasibility of saline infusion sonohysterography-based strain imaging for the determination of stiffness variations in uterine masses in vivo. Strain images are estimated using a 2-dimensional multilevel hybrid algorithm developed for sector array ultrasound transducers. Coarse displacements are initially estimated using envelope echo signals, followed by a guided finer displacement estimation using window lengths on the order of 6 wavelengths and 7 A-lines on radiofrequency data. Strain images are obtained by estimating displacement slopes using least squares estimation. In this prospective study, we show that stiffer masses such as fibroids appear darker or as regions with low strain on strain images and are thus clearly differentiated when compared to normal uterine tissue. A high strain boundary around stiffer masses referred to as a “halo” due to increased slipping or sliding of the mass during the applied deformation is also visualized. Uterine polyps, on the other hand, are visualized as masses that are brighter or regions with high strain when compared to the background myometrium, indicating the presence of a softer mass. Axial strain images provide additional new information that may supplement current clinical B-mode imaging used for the diagnosis of uterine abnormalities. Our results show the feasibility of improving clinical diagnosis based on strain imaging.
fibroids; polyps; saline infusion sonohysterography; strain; strain imaging; uterine cancer
Three-dimensional (3D) umbilical cord blood volume flow measurement with the intention of providing a straightforward, consistent, and accurate method that overcomes the limitations associated with traditional pulsed-wave Doppler flow measurement and provides a means by which to recognize and manage at-risk pregnancies.
The first study involved 3D ultrasound volume flow measurements in seven healthy ewes whose pregnancies ranged from 18 to 19 weeks’ gestation (7 singletons). Sonographic umbilical arterial and venous flow measurements from each fetus were compared to the corresponding average measured arterial/venous flow to assess feasibility of measurement in a static vessel. A second complementary study involved 3D ultrasound volume flow measurements in seven healthy women whose pregnancies ranged from 17.9 to 36.3 weeks’ gestation (6 singletons, 1 twin). Umbilical venous flow measurements were compared to similar flow measurements reported in the literature. Pregnancy outcomes were abstracted from the medical records of the recruited patients.
In the fetal sheep model, arterial/venous flow comparisons yielded errors of 10% or less for eight out of the nine measurements. In the clinical study, venous flow measurements showed agreement with the literature over a range of gestational ages. Two of the seven patients in the clinical study demonstrated lower flow than anticipated for gestational age; one was subsequently diagnosed with intrauterine growth restriction and the other with preeclampsia.
Accurate measurements of umbilical blood volume flow can be performed with relative ease in both the sheep model and in humans using the proposed 3D ultrasound flow measurement technique. Results encourage further development of the method as a means for diagnosis and identification of at-risk pregnancies.
Doppler; volume flow; color flow; umbilical; intrauterine growth restriction
The use of sonography in musculoskeletal research and clinical applications is increasing; however, measurement techniques for diagnosing carpal tunnel syndrome with sonography continue to be inconsistent. Novel methods of measurement using internal comparisons to identify swelling of the median nerve require investigation and comparison to currently used techniques.
The flattening ratio of the median nerve, bowing of the flexor retinaculum, and cross-sectional area of the median nerve were collected in the forearm, at the radio-carpal joint, and at the level of the pisiform in both symptomatic patients and asymptomatic control participants. Electrodiagnostic testing was completed in symptomatic patients as a diagnostic standard.
Median nerve measurements were collected from 166 wrists of symptomatic and asymptomatic participants. The flattening ratio did not show any correlation to electrodiagnostic testing and was identical between both symptomatic and asymptomatic participants. Moderate to strong correlations were noted between electrodiagnostic testing results and sonographic measurements of the cross-sectional area at the pisiform, retinacular bowing, and both the ratio and change of the cross-sectional area between the forearm and pisiform. The area under the curve was large for all receiver operating characteristic curves for each measurement (0.759–0.899), and sensitivity was high (80.4%–82.4%).
Measurement of swelling through a ratio or absolute change had similar diagnostic accuracy as individual measurement of the cross-sectional area within the carpal tunnel. These measures may be useful for improving accuracy in more diverse clinical populations. Further refinement of protocols to identify the largest cross-sectional area within the carpal tunnel region and statistical methods to analyze clustered, multilevel outcome data are recommended to improve diagnostics.
diagnostics; electrodiagnostics; median mononeuropathy; musculoskeletal
To retrospectively evaluate the effect of 3D automated ultrasound (3D-AUS) as an adjunct to digital breast tomosynthesis (DBT) on radiologists’ performance and confidence in discriminating malignant and benign breast masses.
Two-view DBT (CC and MLO or Lateral) and single-view 3D-AUS were acquired on 51 patients with (subsequently) biopsy-proven masses (13 malignant, 38 benign). Six experienced radiologists rated, on a 13-point scale, the likelihood of malignancy of an identified mass, first by reading the DBT alone, followed immediately by reading the DBT with automatically co-registered 3D-AUS. The diagnostic performance of each method was measured using ROC analysis. and changes in sensitivity and specificity with the McNemar test. After each reading, radiologists took a survey to rate their confidence level in using DBT alone vs combined DBT/3D-AUS as potential screening modalities.
The six radiologists had an average area under the ROC curve of 0.92 for both modalities (range 0.89–0.97 for DBT, 0.90–0.94 for DBT/3D-AUS). With BI-RADS rating of 4 as the threshold for biopsy recommendation, the average sensitivity of the radiologists increased from 96% to 100% (p>0.08) with 3D-AUS, while the specificity decreased from 33% to 25% (p>0.28). Survey responses indicated an increased confidence in potentially using DBT for screening when 3D-AUS was added (p<0.05 for each reader).
In this initial reader study, no significant difference in ROC performance was found with the addition of 3D-AUS to DBT. However, a trend to an improved discrimination of malignancy was observed when adding 3D-AUS. Radiologists’ confidence also improved with DBT/3DAUS compared to DBT alone.
Automated Ultrasound; Tomosynthesis; Breast; Reader Study
The feasibility of visualizing atherosclerotic plaque using parametric subharmonic intravascular ultrasound (IVUS) was investigated in vivo.
Atherosclerosis was induced in the aorta of 2 rabbits. Following injection of Definity (Lantheus Medical Imaging, North Billerica, MA), radiofrequency IVUS signals were acquired at 40 MHz with a Galaxy IVUS scanner (Boston Scientific/Scimed, Natick, MA). Subharmonic imaging (SHI; receiving at 20 MHz) was performed offline by applying an 8-order equalization filter. Contrast-to-tissue ratios (CTRs) were computed for the vessel relative to the plaque area over 4 time points. Contrast-to-tissue ratios were also calculated for the plaque-tissue and vessel-tissue from 4 tissue regions of interest at 4 time points. Finally, parametric images showing the cumulative maximum intensity (CMI), time to peak, perfusion (PER), and time-integrated intensity (TII) were generated for the fundamental and subharmonic data sets, and CTR measurements were repeated.
Injection of the contrast agent resulted in improved delineation between plaque and the vessel lumen. Subharmonic imaging resulted in noticeable tissue suppression, although the intensity from the contrast agent was reduced. No significant improvement in the plaque to vessel lumen CTR was observed between the subharmonic and fundamental IVUS (2.1 ± 3.64 versus 2.2 ± 4.20; P = .5). However, the CTR for plaque-tissue was improved (11.8 ± 7.32 versus 9.9 ± 7.06; P < .0001) for SHI relative to fundamental imaging. Cumulative-maximum-intensity and TII maps of both fundamental and subharmonic data provided increased CTRs relative to nonparametric data sets (P< .002). Additionally, the CMI, PER, and TII of SHI IVUS showed significantly improved vessel-plaque CTRs for SHI relative to the fundamental (P < .04).
Parametric SHI IVUS of atherosclerotic plaque is feasible and improves the visualization of the plaque.
atherosclerotic plaque; intravascular ultrasound; parametric imaging; subharmonic imaging