Improving the Efficacy of ACR TI-RADS Through Deep Learning-Based Descriptor Augmentation

Thyroid nodules occur in up to 68% of people, 95% of which are benign. Of the 5% of malignant nodules, many would not result in symptoms or death, yet 600,000 FNAs are still performed annually, with a PPV of 5-7% (up to 30%). Artificial intelligence (AI) systems have the capacity to improve diagnostic accuracy and workflow efficiency when integrated into clinical decision pathways. Previous studies have evaluated AI systems against physicians, whereas we aim to compare the benefits of incorporating AI into their final diagnostic decision. This work analyzed the potential for artificial intelligence (AI)-based decision support systems to improve physician accuracy, variability, and efficiency. The decision support system (DSS) assessed was Koios DS, which provides automated sonographic nodule descriptor predictions and a direct cancer risk assessment aligned to ACR TI-RADS. The study was conducted retrospectively between (08/2020) and (10/2020). The set of cases used included 650 patients (21% male, 79% female) of age 53 ± 15. Fifteen physicians assessed each of the cases in the set, both unassisted and aided by the DSS. The order of the reading condition was randomized, and reading blocks were separated by a period of 4 weeks. The system's impact on reader accuracy was measured by comparing the area under the ROC curve (AUC), sensitivity, and specificity of readers with and without the DSS with FNA as ground truth. The impact on reader variability was evaluated using Pearson's correlation coefficient. The impact on efficiency was determined by comparing the average time per read. There was a statistically significant increase in average AUC of 0.083 [0.066, 0.099] and an increase in sensitivity and specificity of 8.4% [5.4%, 11.3%] and 14% [12.5%, 15.5%], respectively, when aided by Koios DS. The average time per case decreased by 23.6% (p = 0.00017), and the observed Pearson's correlation coefficient increased from r = 0.622 to r = 0.876 when aided by Koios DS. These results indicate that providing physicians with automated clinical decision support significantly improved diagnostic accuracy, as measured by AUC, sensitivity, and specificity, and reduced inter-reader variability and interpretation times.

Detected prenatal perfluorooctanoic acid (PFOA) exposure is associated with decreased fetal head biometric parameters in participants experiencing higher perceived stress during pregnancy in the MADRES cohort

BACKGROUND

Perfluoroalkyl substances (PFAS) are ubiquitous synthetic chemicals with long half-lives and are known to cross the placenta during pregnancy. We examined the influence of maternal PFAS levels on in utero fetal growth trajectories and assessed whether maternal stress modified these associations.

METHODS

Blood serum concentrations of five PFAS (PFOS, PFHxS, PFNA, PFOA, PFDA) were measured in 335 prenatal specimens (mean gestational age (GA): 21±9 weeks) in the MADRES cohort. Fetal growth outcomes (head circumference (HC), abdominal circumference (AC), biparietal diameter (BPD), femur length (FL), and estimated fetal weight (EFW)) were abstracted from ultrasound medical records and measured at the 3rd trimester study visit (N = 833 scans, GA range 10-42 weeks, mean 2.4 scans/participant). Adjusted linear mixed models with a GA quadratic growth curve were used for each PFAS exposure and growth outcome. PFOS and PFHxS were modeled continuously (100% sample detection), while PFOA, PFNA, and PFDA were modeled categorically (57-70% sample detection). Scores on the Perceived Stress Scale (PSS) measured in pregnancy were dichotomized at the median (<13 vs. ≥ 13) in stratified models.

RESULTS

Participants were on average 29±6 years old and predominately Hispanic (76%). Median serum concentrations of PFOS, PFHxS, PFNA, PFOA and PFDA were 1.34, 1.10, 0.07, 0.12, and 0.04 ng/mL, respectively. Participants with detected PFOA concentrations had fetuses with -2.5 mm (95% CI -4.2, -0.8) smaller HC and-0.7 mm (95% CI -1.3, -0.2) smaller BPD on average for a fixed GA than those without detected PFOA concentrations. In models stratified by PSS level, the effects of PFOA on fetal growth parameters were stronger and only significant in participants with higher stress levels (HC: β= -3.5, 95% CI -5.8, -1.4; BPD: β = -0.8, 95% CI -1.6, -1.1).

CONCLUSIONS

Prenatal PFOA exposure adversely impacted fetal head biometric parameters in participants experiencing higher stress during pregnancy.

Utility of Contrast-Enhanced Ultrasound and 4-Dimensional Computed Tomography for Preoperative Detection and Localization of Parathyroid Adenomas Compared With Surgical Results

OBJECTIVES

To investigate the accuracy, sensitivity, and specificity of contrast-enhanced ultrasound (CEUS) for detection of parathyroid adenomas and compare it to those of 4-dimensional computed tomography (4DCT), which has been established as a reliable, effective tool for preoperative localization of parathyroid adenomas.

METHODS

About 27 patients with suspected parathyroid pathology underwent imaging evaluations with 4DCT and CEUS and 22 patients subsequently underwent surgical resection of parathyroid lesions. 4DCT and CEUS were performed and interpreted by consensus of two expert radiologists with extensive experience in each modality. Assessment for the side, z-axis (craniocaudal axis), and quadrant of the pathologically proven lesion was performed based on the surgical report.

RESULTS

For single-gland disease, the accuracy for CEUS localization to the correct quadrant and side were 81.0 and 90.1% respectively. For single-gland disease, the accuracy for 4DCT localization to the correct quadrant and side were 81.0 and 90.5% respectively. 4DCT localization sensitivity and specificity were comparable to those for CEUS. 4DCT allowed for accurate diagnosis in multigland disease in contradistinction to CEUS.

CONCLUSIONS

CEUS is a noninvasive, real-time imaging technique that has relatively high diagnostic confidence and accuracy of localization which are comparable to the accuracy of 4DCT for preoperative parathyroid adenoma detection, characterization, and localization. This technique should be considered for primary preoperative diagnosis, especially in younger patients.

Prenatal Perfluorooctanoic Acid (PFOA) Exposure Is Associated With Lower Infant Birthweight Within the MADRES Pregnancy Cohort

Introduction

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are persistent synthetic chemicals found in household products that can cross the placenta during pregnancy. We investigated whether PFAS exposure during pregnancy was associated with infant birth outcomes in a predominantly urban Hispanic population.

Methods

Serum concentrations of perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were measured in 342 prenatal biospecimens (mean gestational age: 21 ± 9 weeks) from participants in the ongoing Maternal And Developmental Risks from Environmental and Social Stressors (MADRES) cohort. PFAS compounds were modeled continuously or categorically, depending on the percentage of samples detected. The birth outcomes assessed were birthweight, gestational age at birth, and birthweight for gestational age (BW-for-GA) z-scores that accounted for parity or infant sex. Single pollutant and multipollutant linear regression models were performed to evaluate associations between PFAS exposures and birth outcomes, adjusting for sociodemographic, perinatal, and study design covariates.

Results

Maternal participants (n = 342) were on average 29 ± 6 years old at study entry and were predominantly Hispanic (76%). Infants were born at a mean of 39 ± 2 weeks of gestation and weighed on average 3,278 ± 522 g. PFOS and PFHxS were detected in 100% of the samples while PFNA, PFOA, and PFDA were detected in 70%, 65%, and 57% of the samples, respectively. PFAS levels were generally lower in this cohort than in comparable cohorts. Women with detected levels of PFOA during pregnancy had infants weighing on average 119.7 g less (95% CI -216.7, -22.7) than women with undetected levels of PFOA in adjusted single pollutant models. PFOA results were also statistically significant in BW-for-GA z-score models that were specific for sex or parity. In models that were mutually adjusted for five detected PFAS compounds, PFOA results remained comparable; however, the association was only significant in BW-for-GA z-scores that were specific for parity (β = -0.3; 95% CI -0.6, -0.01). We found no significant adjusted associations with the remaining PFAS concentrations and the birth outcomes assessed.

Conclusion

Prenatal exposure to PFOA was associated with lower birthweight in infants, suggesting that exposure to these chemicals during critical periods of development might have important implications for children's health.

Contrast-Enhanced Ultrasound for the Evaluation of Renal Transplants

Contrast-enhanced ultrasound has emerged as a useful imaging modality for the evaluation of the transplant kidney. Advantages over traditional imaging modalities such as computed tomography and magnetic resonance imaging include the ability to visualize a lesion's enhancement pattern in real time, the lack of nephrotoxicity, and relatively low cost. Potential uses of contrast-enhanced ultrasound include characterization of solid and cystic transplant renal masses, assessment for pyelonephritis and identification of its complications, and evaluation of transplant complications in immediate and delayed settings. Contrast-enhanced ultrasound will likely play an increasing role for evaluating the transplant kidney, as an accurate diagnosis based on imaging can direct treatment and prevent unnecessary interventions.

Thyroid Imaging Reporting and Data System (TI-RADS): A User's Guide

In 2017, the Thyroid Imaging Reporting and Data System (TI-RADS) Committee of the American College of Radiology (ACR) published a white paper that presented a new risk-stratification system for classifying thyroid nodules on the basis of their appearance at ultrasonography (US). In ACR TI-RADS, points in five feature categories are summed to determine a risk level from TR1 to TR5. Recommendations for biopsy or US follow-up are based on the nodule's ACR TI-RADS level and its maximum diameter. The purpose of this article is to offer practical guidance on how to implement and apply ACR TI-RADS based on the authors' experience with the system. ^© RSNA, 2018.

Applications of contrast-enhanced ultrasound in the kidney

Incidental discovery of renal lesions on cross-sectional imaging studies performed for other indications is not uncommon. With the increased reliance on medical imaging, the number of incidentally detected renal lesions has also grown over time. While simple cysts account for the majority of these lesions, the presence of complex features within a cystic lesion, such as septations and solid components, can present a confusing picture. Solid lesions, too, can be indeterminate, and distinguishing between benign solid masses (like lipid-poor angiomyolipomas and oncocytomas) and renal cell carcinoma affects patient management and can prevent unnecessary interventions. Indeterminate renal lesions are traditionally further characterized by multiphase imaging, such as contrast-enhanced computed tomography and magnetic resonance imaging. Contrast-enhanced ultrasound (CEUS) is a new, relatively inexpensive technique that has become increasingly employed in the diagnostic workup of indeterminate renal lesions. With its lack of nephrotoxicity, the absence of ionizing radiation, and the ability to evaluate the enhancement pattern of renal lesions quickly and in real-time, CEUS has unique advantages over traditional imaging modalities. This article provides an overview of the current clinical applications of CEUS in characterizing renal lesions, both cystic and solid. Additional applications of CEUS in the kidney, including its roles in renal transplant evaluation and guidance for percutaneous biopsy, will also be briefly discussed.

Artifacts in contrast-enhanced ultrasound: a pictorial essay

Although contrast-enhanced ultrasound (CEUS) has become a widely utilized and accepted modality in much of the world, the associated contrast agents have only recently received approval in the United States. As with all radiological techniques, image artifacts are encountered in CEUS, some of which relate to commonly encountered ultrasound artifacts, while others are unique to this technique. Image artifacts must be recognized when performing and interpreting examinations to improve technique and diagnostic accuracy. In this article, we review artifacts that may be encountered in CEUS, and where possible discuss how to minimize them or mitigate their effect on image quality and interpretation.

Practical advantages of contrast-enhanced ultrasound in abdominopelvic radiology

Computed tomography (CT) and magnetic resonance imaging (MRI) are two of the workhorse modalities of abdominopelvic radiology. However, these modalities are not without patient- and technique-specific limitations that may prevent a timely and accurate diagnosis. Contrast-enhanced ultrasound (CEUS) is an effective, rapid, and cost-effective imaging modality with expanding clinical utility in the United States. In this pictorial essay, we provide a case-based discussion demonstrating the practical advantages of CEUS in evaluating a variety of pathologies in which CT or MRI was precluded or insufficient. Through these advantages, CEUS can serve a complementary role with CT and MRI in comprehensive abdominopelvic radiology.

ACR Thyroid Imaging, Reporting and Data System (TI-RADS): White Paper of the ACR TI-RADS Committee

classification that is widely used in breast imaging, their authors chose to apply the acronym TI-RADS, for Thyroid Imaging, Reporting and Data System. In 2012, the ACR convened committees to (1) provide recommendations for reporting incidental thyroid nodules, (2) develop a set of standard terms (lexicon) for ultrasound reporting, and (3) propose a TI-RADS on the basis of the lexicon. The committees published the results of the first two efforts in 2015. In this article, the authors present the ACR TI-RADS Committee's recommendations, which provide guidance regarding management of thyroid nodules on the basis of their ultrasound appearance. The authors also describe the committee's future directions.

Versatile utilization of real-time intraoperative contrast-enhanced ultrasound in cranial neurosurgery: technical note and retrospective case series

OBJECTIVE

Intraoperative contrast-enhanced ultrasound (iCEUS) offers dynamic imaging and provides functional data in real time. However, no standardized protocols or validated quantitative data exist to guide its routine use in neurosurgery. The authors aimed to provide further clinical data on the versatile application of iCEUS through a technical note and illustrative case series.

METHODS

Five patients undergoing craniotomies for suspected tumors were included. iCEUS was performed using a contrast agent composed of lipid shell microspheres enclosing perflutren (octafluoropropane) gas. Perfusion data were acquired through a time-intensity curve analysis protocol obtained using iCEUS prior to biopsy and/or resection of all lesions.

RESULTS

Three primary tumors (gemistocytic astrocytoma, glioblastoma multiforme, and meningioma), 1 metastatic lesion (melanoma), and 1 tumefactive demyelinating lesion (multiple sclerosis) were assessed using real-time iCEUS. No intraoperative complications occurred following multiple administrations of contrast agent in all cases. In all neoplastic cases, iCEUS replicated enhancement patterns observed on preoperative Gd-enhanced MRI, facilitated safe tumor debulking by differentiating neoplastic tissue from normal brain parenchyma, and helped identify arterial feeders and draining veins in and around the surgical cavity. Intraoperative CEUS was also useful in guiding a successful intraoperative needle biopsy of a cerebellar tumefactive demyelinating lesion obtained during real-time perfusion analysis.

CONCLUSIONS

Intraoperative CEUS has potential for safe, real-time, dynamic contrast-based imaging for routine use in neurooncological surgery and image-guided biopsy. Intraoperative CEUS eliminates the effect of anatomical distortions associated with standard neuronavigation and provides quantitative perfusion data in real time, which may hold major implications for intraoperative diagnosis, tissue differentiation, and quantification of extent of resection. Further prospective studies will help standardize the role of iCEUS in neurosurgery.

Duplex Doppler sonography: is there clinical relevance to elevated renal vein velocity in kidney transplants?

PURPOSE

This study aims to determine a velocity threshold in the main renal vein (MRV) of renal transplants and evaluate the cause and clinical significance of elevated velocity.

METHODS

Maximum MRV velocity from 331 consecutive renal transplant Doppler ultrasounds in 170 patients was recorded. A priori, twice the median MRV velocity was selected as the threshold for elevation. Ultrasounds were divided into "early" and "late" periods based on time after transplantation. Charts were reviewed for outcomes associated with elevated MRV velocity. Endpoints included graft failure or death. Serum creatinine (Cr) levels among groups were compared, and temporal changes in MRV velocity were plotted.

RESULTS

A ≥70 cm/s was chosen as the threshold for elevated MRV velocity. Graft failure and complication/intervention rates were higher only in the "late" group with elevated MRV velocity. There was no association between elevated MRV velocity and death, no predilection for a particular biopsy result, and no difference in Cr levels among groups. The majority of elevated velocities occurred during the immediate postoperative period and resolved without intervention.

CONCLUSIONS

Elevated MRV velocity in the early postoperative period is a transient phenomenon not correlating with outcome or requiring intervention. In the late period, elevated MRV velocity is associated with entities including hydronephrosis, perinephric collections, and arteriovenous fistulae.

Thyroid Ultrasound Reporting Lexicon: White Paper of the ACR Thyroid Imaging, Reporting and Data System (TIRADS) Committee

Ultrasound is the most commonly used imaging technique for the evaluation of thyroid nodules. Sonographic findings are often not specific, and definitive diagnosis is usually made through fine-needle aspiration biopsy or even surgery. In reviewing the literature, terms used to describe nodules are often poorly defined and inconsistently applied. Several authors have recently described a standardized risk stratification system called the Thyroid Imaging, Reporting and Data System (TIRADS), modeled on the BI-RADS system for breast imaging. However, most of these TIRADS classifications have come from individual institutions, and none has been widely adopted in the United States. Under the auspices of the ACR, a committee was organized to develop TIRADS. The eventual goal is to provide practitioners with evidence-based recommendations for the management of thyroid nodules on the basis of a set of well-defined sonographic features or terms that can be applied to every lesion. Terms were chosen on the basis of demonstration of consistency with regard to performance in the diagnosis of thyroid cancer or, conversely, classifying a nodule as benign and avoiding follow-up. The initial portion of this project was aimed at standardizing the diagnostic approach to thyroid nodules with regard to terminology through the development of a lexicon. This white paper describes the consensus process and the resultant lexicon.

Salsalate treatment improves glycemia without altering adipose tissue in nondiabetic obese hispanics

OBJECTIVE

Salsalate treatment has well-known effects on improving glycemia, and the objective of this study was to examine whether the mechanism of this effect was related to changes in adipose tissue.

METHODS

A randomized double-blind and placebo-controlled trial in obese Hispanics (18-35 years) was conducted. The intervention consisted of 4 g day(-1) of salsalate (n = 11) versus placebo (n = 13) for 4 weeks. Outcome measures included glycemia, adiposity, ectopic fat, and adipose tissue gene expression and inflammation.

RESULTS

In those receiving salsalate, plasma fasting glucose decreased by 3.4% (P < 0.01), free fatty acids decreased by 42.5% (P = 0.06), and adiponectin increased by 27.7% (P < 0.01). Salsalate increased insulin AUC by 38% (P = 0.01) and HOMA-B by 47.2% (P < 0.01) while estimates of insulin sensitivity/resistance were unaffected. These metabolic improvements occurred without changes in total, abdominal, visceral, or liver fat. Plasma markers of inflammation/immune activation were unchanged following salsalate. Salsalate had no effects on adipose tissue including adipocyte size, presence of crown-like structures, or gene expression of adipokines, immune cell markers, or cytokines downstream of NF-κB with the exception of downregulation of IL-1β (P < 0.01).

CONCLUSIONS

Findings suggest that metabolic improvements in response to salsalate occurred without alterations in adiposity, ectopic fat, or adipose tissue gene expression and inflammation.

Contrast-enhanced ultrasound of the liver and kidney

The clinical use of noncardiac contrast-enhanced ultrasound scan (CEUS) has been steadily gaining momentum. CEUS is a reliable and safe technique with a diverse array of applications. This article reviews the current and potential future clinical applications of CEUS. Emphasis will be placed on evaluating focal lesions with the liver and kidney. Contrast agent composition and mechanism are also briefly reviewed.

A novel biopsy method to increase yield of subcutaneous abdominal adipose tissue

Collection of abdominal subcutaneous adipose tissue (SAT) for research testing is traditionally performed using punch biopsy or needle aspiration techniques, yielding small amounts of very superficial SAT (100-500 mg). Although liposuction techniques can be used to obtain large amounts of SAT, these approaches can compromise the integrity of the adipose tissue. Therefore, we investigated a novel method using a 6-mm Bergström side-cutting biopsy needle to acquire suitable amounts of intact abdominal SAT for multiple complex studies such as flow cytometry, RNA extraction, ex vivo expression of molecular and post-translational protein mediators, and histology. Fifty biopsies were obtained from 29 participants using a Bergström biopsy needle, applying transient manual suction and shearing large pieces of fat within the inner-cutting trochar. Eighteen of the biopsies were performed under ultrasound guidance, whereby we successfully sampled deep SAT (dSAT) from below Scarpa's fascia. The average weight of SAT sampled was 1.5 ± 0.4 g. There was no clinically important bleeding or ecchymosis on the abdominal wall and no infection occurred with this procedure. The 6-mm Bergström biopsy needle yielded substantially more SAT than what has been obtained from superficial procedures and, for the first time, allowed sampling of dSAT by a percutaneous approach.

Breast lesions: evaluation with shear wave elastography, with special emphasis on the "stiff rim" sign

PURPOSE

To analyze the diagnostic performance of shear wave elastography (SWE) in differentiating between benign and malignant breast lesions, with special emphasis on the value of the "stiff rim" sign, as compared with conventional ultrasonography (US).

MATERIALS AND METHODS

For this ethics committee-approved retrospective study, all patients provided verbal informed consent for the analysis of their imaging data. A total of 193 consecutive women (age range, 18-82 years; mean age, 46 years) with 193 breast lesions (56 malignant, 137 benign) were included. The stiff rim sign, a qualitative SWE feature, was evaluated at the display setting of less than 180 kPa and at 180 kPa. The quantitative SWE features were assessed. Sensitivity, specificity, the area under the receiver operating characteristic curve (Az), and positive and negative likelihood ratios were calculated for conventional US features, for SWE features, and for combined conventional US and SWE features.

RESULTS

Among all qualitative and quantitative SWE features, the stiff rim sign at the display setting (<180 kPa) showed the highest Az (0.918; 95% confidence interval [CI]: 0.870, 0.953), which was comparable to that for conventional US (0.891; 95% CI: 0.838, 0.931) (P = .40). The combination of the stiff rim sign at less than 180 kPa and conventional US features, with a positive likelihood ratio of 12.23 (95% CI: 11.5, 13.0) and a negative likelihood ratio of 0.02 (95% CI: 0.003, 0.1), yielded the highest Az (0.982; 95% CI: 0.951, 0.995)-higher than those for conventional US only and for any single SWE feature alone (P < .001 for all)-and yielded higher sensitivity (98.2% [55 of 56]; 95% CI: 90.4%, 100.0%) and similar specificity (92.0% [126 of 137]; 95% CI: 86.1%, 95.9%) compared with conventional US (P < .001 and P = .58, respectively). With use of this combination, the rate of recommendation of benign lesions for interventional procedures would decrease from 56.9% (78 of 137) (on the basis of conventional US features) to 15.3% (21 of 137), and 100.0% (56 of 56) (95% CI: 93.6%, 100.0%) malignant lesions would be correctly selected for biopsy.

CONCLUSION

Adding SWE features, especially the stiff rim sign at the display setting (<180 kPa), to conventional US has the potential to improve the differentiation of breast lesions.

Comparison of fine-needle aspiration and fine-needle capillary sampling of thyroid nodules: a prospective study with emphasis on the influence of nodule size

BACKGROUND

The objective of this study was to compare the sampling efficiency of ultrasound-guided fine-needle aspiration (FNA) and fine-needle capillary (FNC) sampling in thyroid nodules, in which the authors specifically analyzed the influence of nodule size.

METHODS

This study included 280 thyroid nodules in 275 consecutive patients. The nodules were divided into 4 size subgroups: ≤5.0 mm, from 5.1 to 10.0 mm, from 10.1 to 20.0 mm, and >20.0 mm. Each nodule was sampled by both FNA and FNC. The final cytopathologic findings were reported. The smears were scored and then categorized as diagnostically inadequate, adequate, or superior on the basis of 4 parameters, which included background clot or blood, the number of obtained cells, preserved tissue architecture, and cellular degeneration.

RESULTS

The κ scores for agreement of the cytopathologic results between FNA and FNC sampling in the 4 size subgroups were 0.377, 0.455, 0.751, and 0.352 for nodules that measured ≤5.0 mm, from 5.1 to 10.0 mm, from 10.1 to 20.0 mm, and >20.0 mm, respectively. The proportion of nondiagnostic of FNAs was significantly lower than the proportion of nondiagnostic FNC samples in nodules that measured >20.0 mm (P = .037). Scores for the 4 diagnostic parameters were significantly greater in FNAs than in FNC samples in nodules that measured from 5.1 to 10.0 mm and >20.0 mm (all P < .05); however, similar results were not observed in the nodules that measured ≤5.0 mm or from 10.1 to 20.0 mm (all P > .05). Also, FNA yielded significantly more diagnostically superior specimens than FNC sampling in nodules that measured from 5.1 to 10.0 mm and >20.0 mm (P < .05 for both).

CONCLUSIONS

The current findings indicated that FNA may be more suitable than FNC for sampling nodules that measure from 5.1 to 10.0 mm and >20.0 mm; whereas, for nodules that measure ≤5.0 mm and from 10.1 to 20.0 mm, the 2 techniques could yield specimens with similar quality.

Evaluation of ultrasound-assisted thrombolysis using custom liposomes in a model of retinal vein occlusion

PURPOSE

To study the potential efficacy of ultrasound (US) assisted by custom liposome (CLP) destruction as an innovative thrombolytic tool for the treatment of retinal vein occlusion (RVO).

METHODS

Experimental RVO was induced in the right eyes of 40 rabbits using laser photothrombosis; the US experiment took place 48 hours later. Rabbits were randomly divided into four equal groups: US+CLP group, US+saline group, CLP+sham US group, and no treatment group. The latter three groups acted as controls. Fundus fluorescein angiography and Doppler US were used to evaluate retinal blood flow.

RESULTS

CLP-assisted US thrombolysis resulted in restoration of flow in seven rabbits (70%). None of the control groups showed significant restoration of retinal venous blood flow.

CONCLUSIONS

US-assisted thrombolysis using liposomes resulted in a statistically significant reperfusion of retinal vessels in the rabbit experimental model of RVO. This approach might be promising in the treatment of RVO in humans. Further studies are needed to evaluate this approach in patients with RVO. Ultrasound assisted thrombolysis can be an innovative tool in management of retinal vein occlusion.

Nonshadowing echogenic foci in thyroid nodules: are certain appearances enough to avoid thyroid biopsy?

OBJECTIVES

The purpose of this study was to further classify nonshadowing echogenic foci and examine the association with malignancy.

METHODS

This study received Institutional Review Board approval and was Health Insurance Portability and Accountability Act compliant. A total of 371 consecutive thyroid nodules were evaluated in 189 patients (177 female and 12 male; mean age, 59 years; range, 21-92 years). Eighty-six nodules (23%) measured 5 mm or larger and contained nonshadowing echogenic foci with a mean nodule diameter of 16 mm (5-66 mm). Blinded review of these nodules 12 months later was performed. Echogenic foci were classified as follows: showing a comet tail artifact (type 1), linear and brightly echogenic (type 2), round and indeterminate (type 3), and microcalcifications (type 4). All available thyroid sonograms and pathologic data were then reviewed.

RESULTS

Nineteen nodules (22%) showed a classic comet tail artifact, with malignancy in 0 of 19. Six (32%) had negative pathologic results, and 9 (47%) had stable imaging follow-up (mean, 37 months). Twenty-nine nodules (34%) showed linear and brightly echogenic foci, with malignancy in 0 of 29. Fifteen (52%) had negative pathologic results, and 11 (38%) had stable imaging follow-up (mean, 34 months). Twenty-four nodules (28%) showed round and indeterminate echogenic foci, with 1 of 24 (4%) containing papillary carcinoma. Thirteen (54%) had negative pathologic results, and 8 (33%) had stable imaging follow-up (mean, 24 months). Fourteen nodules (16%) contained microcalcifications, with 4 of 14 (29%) containing papillary thyroid cancer. Nine (64%) had negative pathologic results, and 1 (7%) had stable imaging follow-up (63 months).

CONCLUSIONS

Nonshadowing brightly echogenic linear foci with or without a comet tail artifact may be a benign finding. Confirmatory studies are needed for this result to be applied clinically.

Contrast-enhanced ultrasonographic findings of different histopathologic types of breast cancer

BACKGROUND

The new application of contrast-enhanced ultrasonography (CEUS) in the diagnosis of breast masses has evolved quickly only in recent years. Nevertheless, mixed results owing to the overlap in characteristics of benign and malignant lesions are simultaneously discovered by most studies, partially attributed to different histopathologic characteristics of breast cancer.

PURPOSE

To explore the characteristics of different histopathologic types of breast cancer at real-time gray-scale CEUS and evaluate its diagnostic value.

MATERIAL AND METHODS

One hundred and one histopathologically confirmed malignant lesions were included. We retrospectively reviewed the contrast-enhanced ultrasonographic findings including morphologic features, quantitative parameters, and correlated them with histopathology. True-positive rate was calculated to assess the diagnostic performance of CEUS.

RESULTS

The 101 malignancies displayed irregular shape (72 [71%]), poorly-defined margin (73 [72%]), penetrating or tortuous surrounding vessels (79 [78%]), heterogeneous enhancement (84 [83%]), including focal perfusion defects (24 [24%]). For each histopathologic type, 87% (58/67) of invasive ductal carcinoma (IDC) showed heterogeneous enhancement. Of all the 24 perfusion defects, IDC account for 88% (21/24). Low average peak intensity (PI) of 4.9 was detected in this type. Ductal carcinoma in situ (DCIS) excellently showed the features of irregular shape (82% [14/17]), poorly-defined margin (82% [14/17]), heterogeneous enhancement (94% [16/17]). While 83% (5/6) of medullary carcinoma exhibited regular shape, well-defined margin, homogenous enhancement, and high average PI value of 9.6. Invasive lobular carcinoma showed similar enhancement pattern to that of IDC. Intraductal papillary carcinoma displayed high average PI value of 8.1. The overall true-positive rate for conventional US and CEUS was 88%, 86%, respectively. DCIS, medullary carcinoma, and intraductal papillary carcinoma achieved an improved true-positive rate (94%, 100% and 100%, respectively).

CONCLUSION

The imaging characteristics of CEUS are variable in different histopathologic types of breast cancer. CEUS does not appear to be superior to conventional ultrasound as a diagnostic tool overall, however, it is a useful adjunct to conventional ultrasound in diagnosing some special types of breast cancer.

US-guided fine-needle aspiration of major salivary gland masses and adjacent lymph nodes: accuracy and impact on clinical decision making

PURPOSE

To determine whether ultrasonography (US)-guided fine-needle aspiration (FNA) is an effective technique for diagnosing masses in the salivary gland and adjacent lymph nodes.

MATERIALS AND METHODS

The institutional review board waived the requirement to obtain informed consent and approved this HIPAA-compliant retrospective study. Radiology records of 50 patients (28 female patients aged 25-85 years [median age, 58 years], 22 male patients aged 11-82 years [median age, 62 years]) who underwent 52 consecutive US-guided FNA procedures from 2004 to 2009 were reviewed. In 46 cases, lesions were sampled for biopsy under real-time US guidance by means of three passes with a 25-gauge needle. In six cases, two subsequent passes were performed with a 22-gauge needle after the first pass showed minimal or no aspirate. Findings from cytopathologic analysis, clinical follow-up, and surgery were evaluated and compared.

RESULTS

A diagnostically adequate biopsy specimen was obtained in 48 of the 52 cases (92%). Among the 20 patients who underwent surgical intervention after diagnostic US-guided FNA findings, results of surgical-pathologic analysis helped confirm the cytologic diagnosis in 19 (95%). Twenty of the 50 patients (40%) were spared surgical intervention on the basis of findings from US-guided FNA. US-guided FNA did not result in any intra- or postprocedural complications.

CONCLUSION

The diagnostic accuracy of US-guided FNA is similar to that of core needle biopsy, and there were no complications in this study. Information yielded with FNA cytology plays an integral role in clinical decision making in the management of masses in the major salivary glands and adjacent structures.

Forced expression of methionine adenosyltransferase 1A in human hepatoma cells suppresses in vivo tumorigenicity in mice

Methionine adenosyltransferase (MAT) catalyzes the synthesis of S-adenosylmethionine, the principal methyl donor, and is encoded by MAT1A and MAT2A in mammals. Normal liver expresses MAT1A, which is silenced in hepatocellular carcinoma. We have shown that hepatoma cells overexpressing MAT1A grew slower, but whether this is also true in vivo remains unknown. To investigate the effect of overexpressing MAT1A on in vivo tumorigenesis, we generated stable transfectants of Huh7 cells overexpressing either MAT1A or empty vector. Real-time PCR and Western blotting were used to measure expression, and BALB/c nude mice were injected subcutaneously with untransfected or Huh7 cells transfected with empty or MAT1A expression vector to establish tumors. Tumor properties such as proliferation, angiogenesis, and apoptosis were compared, and microarray analysis was performed. Huh7 cells overexpressing MAT1A had higher S-adenosylmethionine levels but lower bromodeoxyuridine incorporation than control cells. Tumor growth rates and weights were lower in MAT1A transfected tumors. In addition, microvessel density and CD31 and Ki-67 staining were lower in MAT1A transfected tumors than control tumors, whereas the apoptosis index was higher in MAT1A-transfected tumors. Forced expression of MAT1A induced genes related to apoptosis and tumor suppression and lowered expression of cell growth and angiogenesis proteins. Our data demonstrate in vivo overexpression of MAT1A in liver cancer cells can suppress tumor growth. They also suggest inducing MAT1A expression might be a strategy to treat hepatocellular carcinoma.

Experiences with a prototype tracking and verification system implemented within an imaging center

RATIONALE AND OBJECTIVES

Most health care facilities currently struggle with protecting medical data privacy, misidentification of patients, and long patient waiting times. This article demonstrates a novel system for a clinical environment using wireless tracking and facial biometric technologies to automatically monitor and identify staff and patients to address these problems.

MATERIALS AND METHODS

The design of the location tracking and verification system (LTVS) was based on a workflow study which was performed to observe the physical location and movement of patient and staff at the Healthcare Consultation Center II (HCC II) running hospital information systems, radiology information systems, picture archive and communication systems, and a voice recognition system. Based on the results from this workflow study, the LTVS was designed using a wireless real-time location system and a facial biometric system integrated with the radiology information system. The LTVS was tested for its functionality in a laboratory environment, then evaluated at HCC II.

RESULTS

Experimental results in the laboratory and clinical environments demonstrated that patient and staff real-time location information and identity verification can be obtained from LTVS. Warning messages can immediately be sent to alert staff when patient's waiting time is over a predefined limit, and unauthorized access to a security area can be audited. Additionally, patient misidentification can be prevented during the course of examinations.

CONCLUSIONS

The system enabled health care providers to streamline the patient workflow, protect against erroneous examinations and create a security zone to prevent, and audit unauthorized access to patient health care data required by the Health Insurance Portability and Accountability Act mandate.

Prospective evaluation of vascular complications after liver transplantation: comparison of conventional and microbubble contrast-enhanced US

PURPOSE

To prospectively compare diagnostic performance of conventional Doppler ultrasonography (US) and microbubble contrast material-enhanced US for assessment of vascular complications after liver transplantation, with clinical follow-up or angiography as reference standard.

MATERIALS AND METHODS

This study was approved by institutional review board and was HIPAA compliant. Written informed consent was obtained. Seventy-two patients (49 men, 23 women; average age, 52.3 years) were included in this study. Patients who had undergone liver transplantation underwent conventional color Doppler and contrast-enhanced US of the liver. Quality of hepatic artery (HA) and portal vein (PV) visualization, contrast material arrival time, and time for complete evaluation of vasculature were compared for both techniques. McNemar test was used to compare vascular flow visualization scores; Student t test was used to compare mean study times with both techniques. Patients without HA flow at Doppler US underwent angiography; those with flow were followed up clinically. McNemar test was used to compare sensitivity of both techniques.

RESULTS

Contrast-enhanced US helped significantly improve flow visualization in hepatic vessels (P < .001). Mean contrast material arrival time was 13.7 seconds +/- 3.8 (standard deviation) in proper HA and 20.7 seconds +/- 6.3 in PV. Mean study time decreased from 27.4 minutes +/- 13.9 to 9.3 minutes +/- 4.5 (P < .01). Doppler US failed to depict HA flow in eight patients; contrast-enhanced US showed flow in six and no flow in two of these patients. Follow-up results confirmed contrast-enhanced US findings. Sensitivity, specificity, and accuracy for Doppler US were 91.3%, 100%, and 91.5%, respectively. Sensitivity, specificity, and accuracy of contrast-enhanced US were all 100%. Sensitivity and accuracy values of the two techniques were significantly different (P < .014); there was no significant difference in specificity (P > .99)

CONCLUSION

Contrast-enhanced US helped improve flow visualization in the HA and PV, decrease scanning time, and correctly differentiate between thrombosis and a patent artery in patients without HA flow at conventional Doppler US.

Innominate Artery Occlusive Disease: Sonographic Findings

OBJECTIVE

The objective of this study was to report the sonographic abnormalities in a group of patients with angiographically proven innominate artery stenosis and occlusion.

MATERIALS AND METHODS

A review of all cerebrovascular sonograms at our institutions was undertaken to identify patients with complete or partial flow reversal in the right vertebral artery and reversal or midsystolic deceleration of flow in any one of the three major segments of the right carotid system (common, internal, or external carotid artery). The distribution and appearance of these abnormalities was evaluated, and the presence or absence of tardus-parvus waveforms was noted in any segment of the right carotid artery. Additionally, a left to right common carotid peak systolic velocity ratio (LCCA/RCCA) was calculated and compared to published normal values. All patients had correlative contrast or MR angiography. Correlation was made between the severity of stenosis as determined by angiographic images and waveform aberrations as well as the more objective LCCA/RCCA ratios.

RESULTS

Twelve patients were identified as having the abnormalities described above in the right vertebral and carotid arteries. Doppler waveforms from the right vertebral artery revealed that eight of the 12 patients had complete reversal of flow at rest. Bidirectional flow was found in the remaining four as manifested by the presence of marked midsystolic deceleration. In the carotid arteries, one patient had complete reversal of flow in all segments of the right carotid system. Waveforms with midsystolic deceleration were identified in at least one of the carotid arteries of the remaining 11 patients: common carotid artery (8/11 = 73%), internal carotid artery (10/11 = 91%), external carotid artery (3/11 = 27%). The average LCCA/RCCA was 3.1 with a range of 1.7 to 5.7 (normal = 0.7-1.3). All patients had severe innominate artery disease (from 70% to occlusion) by contrast angiography or MR angiography. There was no correlation between the angiographically determined degree of stenosis and the Doppler findings.

CONCLUSION

A distinctive pattern of hemodynamic alterations occurs in the right vertebral and carotid arteries of patients with severe innominate artery disease. Findings include reversed or bidirectional flow in the right vertebral artery, the presence of midsystolic deceleration in any of the branches of the right carotid system, and elevated LCCA/RCCA ratio.

Sonographic evaluation of upper extremity deep venous thrombosis

OBJECTIVE

The purpose of this presentation is to review the techniques of performing an upper extremity Doppler examination, in addition to illustrating the sonographic appearances of acute and chronic upper extremity deep venous thrombosis (UEDVT).

METHODS

The risk factors and complications of UEDVT are discussed, and the anatomy of the upper extremity deep venous system as well as examination techniques are described. Cases of acute and chronic deep venous thrombosis were also chosen to illustrate the spectrum of sonographic appearances.

RESULTS

Color Doppler sonography is accurate in the diagnosis of UEDVT. However, in cases of equivocal Doppler findings, or when the sonographic findings are normal but clinical suspicion for central venous thrombosis is high, magnetic resonance or contrast venography is necessary for further evaluation.

CONCLUSIONS

Color Doppler sonography is a rapid and noninvasive technique in the evaluation of venous disease in the upper extremity and is the modality of choice in screening for UEDVT.

Sonographic NASCET index: a new doppler parameter for assessment of internal carotid artery stenosis

BACKGROUND AND PURPOSE

Established Doppler parameters for carotid stenosis assessment do not reflect North American Symptomatic Carotid Endarterectomy Trial (NASCET)-style methodology. We derived a Doppler parameter, termed sonographic NASCET index (SNI), and hypothesized that the SNI would provide greater angiographic correlation and better accuracy in predicting stenosis of 70% or greater than that of currently used peak systolic velocity (PSV) measurements.

METHODS

Inclusion criteria of angiographically proved carotid stenoses of 40-95% and measured proximal and distal internal carotid artery Doppler PSV values were established. Occlusions and near occlusions were specifically excluded. Doppler and angiographic data meeting the inclusion criteria from 32 carotid bifurcations were identified; actual angiographic stenoses ranged 40-89%. SNI values were calculated for each vessel. PSV and SNI were correlated with angiography by using linear regression analysis. Accuracies of SNI and PSV in predicting stenosis of 70% or greater were compared at two thresholds.

RESULTS

Correlation between SNI and angiography was superior to that between PSV and angiography (r2=0.64 vs 0.38). PSV and SNI values that corresponded to 70% angiographic stenosis were 345 cm/s and 45.5, respectively. Accuracy of PSV of 345 cm/s or greater in predicting stenosis of 70% or greater was 78%, compared with 88% for SNI of 45.5 or greater. The SNI value that corresponded to a PSV threshold of 250 cm/s was 33. Accuracy of PSV of 250 cm/s or greater in predicting stenosis of 70% or greater was 81%, compared with 88% for SNI of 33 or greater.

CONCLUSION

Correlation between SNI and angiography was greater than that between PSV and angiography. Accuracy of SNI in predicting stenosis of 70% or greater was also superior to that of PSV at two thresholds. These results suggest that SNI may be a better predictor of high-grade carotid stenosis than is PSV.

Carotid artery stenosis: grayscale and Doppler ultrasound diagnosis--Society of Radiologists in Ultrasound consensus conference

The Society of Radiologists in Ultrasound convened a multidisciplinary panel of experts in the field of vascular ultrasonography (US) to come to a consensus regarding Doppler US for assistance in the diagnosis of carotid artery stenosis. The panel's consensus statement is believed to represent a reasonable position on the basis of analysis of available literature and panelists' experience. Key elements of the statement include the following: First, all internal carotid artery (ICA) examinations should be performed with grayscale, color Doppler, and spectral Doppler US. Second, the degree of stenosis determined at grayscale and Doppler US should be stratified into the categories of normal (no stenosis), less than 50% stenosis, 50 to 69% stenosis, > or =70% stenosis to near occlusion, near occlusion, and total occlusion. Third, ICA peak systolic velocity (PSV) and the presence of plaque on grayscale and/or color Doppler images are primarily used in the diagnosis and grading of ICA stenosis. Two additional parameters (the ICA-to-common carotid artery PSV ratio and ICA end diastolic velocity) may also be used when clinical or technical factors raise concern that ICA PSV may not be representative of the extent of disease. Fourth, ICA should be diagnosed as normal when ICA PSV is less than 125 cm/second and no plaque or intimal thickening is visible, less than 50% stenosis when ICA PSV is less than 125 cm/second and plaque or intimal thickening is visible, 50 to 69% stenosis when ICA PSV is 125 to 230 cm/second and plaque is visible, > or =70% stenosis to near occlusion when ICA PSV is more than 230 cm/second and visible plaque and lumen narrowing are seen, near occlusion when there is a markedly narrowed lumen on color Doppler US, and total occlusion when there is no detectable patent lumen on grayscale US and no flow on spectral, power, and color Doppler US. Fifth, the final report should discuss velocity measurements and grayscale and color Doppler findings. Study limitations should be noted when they exist. The conclusion should state an estimated degree of ICA stenosis as reflected in these categories. The panel also considered various technical aspects of carotid US and methods for quality assessment, and identified several important unanswered questions meriting future research.