Ultrasound Attenuation Imaging vs MRI-PDFF, Echogenicity and Liver Function for Assessing Degree of Steatosis in NAFLD and Non-NAFLD Patients

ABSTRACT

Nonalcoholic fatty liver disease (NAFLD) is a primary cause of parenchymal liver disease globally. There are currently several methods available to test the degree of steatosis in NAFLD patients, but all have drawbacks that limit their use.The objective of this study is to determine if a new technique, ultrasound (US) attenuation imaging (ATI), correlates with magnetic resonance proton density fat fraction imaging and hepatic echogenicity as seen on gray scale US imaging.Fifty-four patients were recruited at the University of Washington Medical Center from individuals who had already been scheduled for hepatic US or magnetic resonance imaging (MRI). All participants then underwent both hepatic MRI proton density fat fraction and US. Ultrasound images were then evaluated using ATI with 2 observers who individually determined relative grayscale echogenicity.Analysis showed positive correlation between ATI- and MRI-determined fat percentage in the case group (Spearman correlation: 0.50; P = 0.015). Furthermore, participants with NAFLD tended to have a higher ATI than controls (median: 0.70 vs 0.54 dB/cm/MHz; P < 0.001).This study demonstrates that US ATI combined with grayscale imaging is an effective way of assessing the degree of steatosis in patients with moderate to severe NAFLD.

Variation in Fetal Weight Percentile Estimates

OBJECTIVES

Weight percentiles are generally reported without any indication of error. This variation can lead a fetus being mistakenly classified erroneously as having intrauterine growth restriction (IUGR) or macrosomia. The goal of this study was to compare estimated weight percentiles with the actual observed weight percentile for each gestational age in a large cohort of fetuses being scanned in our institution.

METHODS

After IRB approval the radiology information system data base was retrospectively searched for all obstetrical US reports obtained during the late second and third trimesters from July 1, 2014, until July 1, 2020. Demographic information, fetal weight, and weight percentile information were obtained from these reports. Quantile-quantile plots were created for all gestational ages and all ethnicities.

RESULTS

Our study included 6259 ultrasounds in 4060 patients. Mean maternal age of the total group was 31.68 years (ranging 15-53 years). When all subjects were considered, the median values in our QQ plots approximated the line of identity. However, there was considerable variation for a given estimate, implying that estimated fetal weight percentiles are only very rough predictors of the actual percentile.

CONCLUSION

Estimated fetal weight percentiles are only very rough predictors of the actual percentile. We therefore suggest that estimates of the weight percentile should be reported along with an estimate of the expected variation. Recognition of variations in weight percentile should be considered in the greater clinical context, and could potentially prevent misdiagnosis of growth restriction and macrosomia as well as the subsequent overutilization of resources, unnecessary interventions, and maternal stress.

Magnetic Resonance Prediction of Lung Maturity in Fetuses With Congenital Diaphragmatic Hernia

ABSTRACT

To determine if lung to liver MR T2 signal ratio is predictive of neonatal outcome in fetuses with congenital diaphragmatic hernia (CDH).After Interal Review Board approval, the PACS systems at the University of Washington and University of Utah were searched for cases having an in utero fetal MR examination diagnostic of CDH. Inclusion criteria were at least 1 prior ultrasound demonstrating a CDH and an MR obtained within 1 week of that prior ultrasound.A total of 69 patients from the University of Utah and 13 from the University of Washington satisfied the inclusion criteria for a total of 82. After adjusting for gestational age and contralateral lung volume, there was little apparent association between contralateral lung to liver MR T2 signal and 5-minute Apgar score and neonatal mortality When considering neonatal Apgar and mortality, increasing contralateral lung volume was significantly associated with lower risk (hazard ratio, 0.40 per doubling; 95% confidence interval, 0.24-0.69; P = 0.001) as expected.Our data demonstrate that the lung to liver MR signal ratio was not predictive of outcome. The measurement of contralateral lung area, and gestational age at the time of the examination (time of diagnosis) are still the best predictors of poor neonatal outcome.

Role of portable ultrasound during a short-term medical service trip to rural Guatemala: a collaborative mission of trainees and physicians

INTRODUCTION

Access to health care in developing countries is scarce. One solution to this problem has been for doctors from the USA to provide single-visit care through short-term medical service trips. There is interest in using ultrasound imaging as a portable diagnostic tool; however, data describing its usefulness are scarce. Therefore, the goal of this study was to determine the usefulness of portable ultrasound imaging during a medical service trip to rural Guatemala.

METHODS

A multidisciplinary team of physicians examined patients at a mobile clinic in Antigua, Guatemala. Patients with clinical indications for ultrasound had their suspected diagnoses recorded before ultrasound testing. After imaging, updated diagnoses were recorded and compared with the pre-test suspected diagnoses to determine how often ultrasound results changed the medical management of the patients and to assess the most common indications for ultrasound imaging.

RESULTS

During the trip, 205 patients were seen. Of these, 24 (12%) were given ultrasound exams. The results of 13 (54%) exams altered their medical management, and the remaining 11 (46%) exams confirmed the pre-test suspected diagnoses. The most common indications for ultrasound testing were suspected cardiac (11 patients, 46%) and gastrointestinal (8 patients, 33%) diseases.

CONCLUSION

Portable ultrasound imaging improved the medical team's ability to diagnose disease and clinically manage patients in a rural medical service trip. Ultrasound imaging may provide a low-cost solution to the growing demand for care in developing countries.

The heart as a spring, the measurement of myocardial bounce to assess left ventricular function on cardiac MR

Little has been reported on the left ventricular myocardial distension (bounce) and its utility to assess cardiac function. The purpose of this study is to determine whether myocardial bounce at end diastole is reproducibly visualized by blinded observers and to determine whether it corresponds to systolic and diastolic function. 144 Consecutive cardiac MR exams between September and December 2017 were selected for analysis. The bounce was graded by two blinded observers, and the change in LV diameter pre and post bounce was measured. The bounce was defined as the rapid change in LV volume that occurs at the end of diastole during atrial contraction just prior to systolic ejection. Inter-reader agreement was summarized using Cohen's kappa. Spearman's rank correlation coefficient was used to evaluate associations between bounce grade and cardiac physiology parameters. Overall agreement was good with unweighted kappa = 0.69 (95% CI 0.60-0.79). Bounce grade was significantly correlated with the average change in LV diameter before and after the bounce (Spearman's rho = 0.76, p < 0.001). Median diameter changes were 0.0, 1.9, and 4.2 mm in grades 0 (no bounce), 1 (small bounce), and 2 (normal), respectively. The bounce lasted 8 to 12 ms in all patients. Bounce grade was significantly correlated with LV EF (Spearman's rho = 0.43, p < 0.001). Median EF was 44%, 51%, and 58% in grades 0, 1, and 2, respectively. Of the 87 patients who had E/A ratio or E/e' ratio measured, bounce grade was also significantly correlated with E/A ratio (r =  - 0.24, p = 0.034) and E/e' ratio (r =  - 0.24, p = 0.022), with lower grades having higher ratio values on average (Table 4). Of the 15 patients with a bounce grade of 0 by one or both readers and EF ≥ 50%, 8 had E/A ratio measurements and 7 had E/e' ratio measurements. The E/A ratio values ranged from 1 to 2.7 (median 1.5). The E/e' ratio values ranged from 4.8 to 9.6 (median 7.7). The simple observation of a normal myocardial bounce during cine loop review of cardiac MR exams was predictive of normal diastolic and systolic cardiac function. Lack of myocardial bounce was highly associated with both systolic and diastolic dysfunction. The subpopulation of patients with loss of myocardial bounce and normal ejection fraction appear to represent patients with early diastolic dysfunction. Further studies with more diastolic dysfunction MRs are needed to examine this relationship. This study suggests changes to the myocardial bounce seen on cardiac MR may be a simple useful tool for detecting cardiac dysfunction. This study is not to replace, but rather aid the clinical diagnosis and management of both diastolic and systolic dysfunction.

Trouble With the Curve: Pearls and Pitfalls in the Evaluation of Fetal Growth

OBJECTIVES

Poor fetal growth is one of the most important findings on an obstetric ultrasound (US) examination. First-trimester US is the most accurate means for dating pregnancies; however, dating based on last menstrual period remains the standard for determining gestational age. Discrepancies between menstrual and US dating can lead to the overdiagnosis of in utero growth restriction (IUGR). This article will demonstrate that as long as the fetal growth falls along a curve that parallels normal growth curves, appropriate growth has occurred regardless of the gestational age and weight percentile that has been assigned to the fetus.

METHODS

Following Institutional Review Board approval (HSD-00002969), 860 third-trimester fetal US examinations were retrospectively evaluated from January 1 through July 1, 2017, to determine whether they had normal growth curves. Outcome data on all cases were obtained from review of the medical records.

RESULTS

Of 216 fetuses (25%) suspected of IUGR based on a weight below the 10th percentile, 6 developed true IUGR: 5 that led to emergent delivery of fetuses weighing less than a 1000 g and 1 in utero fetal demise. The remaining 210 fetuses all had normal outcomes.

CONCLUSIONS

As long as the fetal growth falls along a curve that parallels normal growth curves, appropriate growth has occurred regardless of the gestational age and weight percentile that has been assigned to the fetus.

Histotripsy: The Next Generation of High-Intensity Focused Ultrasound for Focal Prostate Cancer Therapy

This article reviews the most current methods and technological aspects of high-intensity focused ultrasound (HIFU), which is termed histotripsy. The rationale for focal therapy for prostate carcinoma rather than prostatectomy, which is being used extensively throughout Europe and Asia, is presented, and an argument for why HIFU is the modality of choice for primary therapy and recurrent disease is offered. The article presents a review of the technical advances including higher ultrasound beam energy than current thermal HIFU which allows for more accurate tissue targeting, less collateral tissue damage, and faster treatment times. Finally, the article presents a discussion about the advantage of ultrasound guidance for histotripsy in preference to magnetic resonance imaging guidance primarily based on cost, ease of application, and portability.

Propagation Imaging in the Demonstration of Common Shear Wave Artifacts

In this article, we describe our experience with shear wave propagation imaging (SWPI) as an adjunct to 2-dimensional (2D) shear wave elastography (SWE) in a cohort of patients being evaluated for diffuse liver disease. Two-dimensional SWE has been extensively studied in previous publications; however, 2D SWE using propagation images has not been widely described in the literature to date. We observed that when certain artifacts occurred on the color elastograms, highly characteristic changes to shear wave propagation contours were seen, which can help clarify the cause of the artifacts. To our knowledge, the use of SWPI to explain the etiology of artifacts has never been published before. The artifacts described in this article include the capsule reverberation artifact, penetration limitation or dropout artifact, artifact due to blood vessels, shadowing artifact, tissue motion artifact, and near-field distortion/precompression artifact. Hence, the purpose of this article is to show examples of common artifacts seen on 2D SWE as depicted on corresponding SWPI to demonstrate that both types of image displays are complementary to each other.

Inter-observer Variability in the American College of Radiology Thyroid Imaging Reporting and Data System: In-Depth Analysis and Areas for Improvement

The American College of Radiology (ACR) introduced a new standardized system for management of thyroid nodules, the Thyroid Imaging Reporting and Data System (TI-RADS). The purpose of this retrospective study is to evaluate the inter-observer variability in applying TI-RADS in clinical practice without prior dedicated training. We evaluated a total of 180 nodules constituting all consecutive thyroid aspirations performed in the radiology department between January 1, 2014 and June 30, 2014, with exclusion of histologically inadequate samples. Four radiologists, blinded to each other's evaluation and to final pathology results, evaluated all of the nodules based on the TI-RADS lexicon. TI-RADS score and management recommendations were then deduced from the inputted features. Statistical analysis was performed to determine inter-observer agreement among all readers, as well as between each two readers, in all TI-RADS sonographic features and for recommended management per TI-RADS score with multi-user Cohen's κ (Light's κ) and percentage agreement using R. There was fair-to-moderate inter-observer agreement in nodule composition (two-reader κ range: 0.327-0.533) and presence of calcifications (κ range: 0.229-0.527), but poor-to-fair agreement in echogenicity (κ range: 0.141-0.355), shape (κ range: 0.0729-0.513) and margins (κ range: 0.176-0.283). There was fair inter-observer agreement regarding management recommendations (κ range: 0.242-0.359).

Comparison of Superb Microvascular Imaging With Color Flow and Power Doppler Imaging of Small Hepatocellular Carcinomas

OBJECTIVES

The purpose of this study was to compare Superb Microvascular Imaging (SMI; Toshiba America Medical Systems, Tustin, CA) with conventional color flow Doppler (CFD) and power Doppler (PD) imaging in the liver to distinguish between malignant and benign liver neoplasms.

METHODS

After Institutional Review Board approval (number 449984-ED), patients undergoing routine pre-radiofrequency ablation planning ultrasound examinations for suspected hepatocellular carcinomas (HCCs) of less than 2 cm in diameter between January 1, 2015, and July 1, 2016, were prospectively identified. Four readers reviewed the ultrasound images independently for the presence or absence of flow centrally and along the periphery of the lesion.

RESULTS

Higher peripheral vessel grades were found on SMI than CFD (P < .001) and PD (P < .001) imaging: in particular, more grade 2 (39% versus 16% and 11%, respectively) and grade 3 (8% versus 0% and 0%). Overall, more central and peripheral vessels were found on SMI than CFD and PD imaging for both HCC lesions (P < .001) and benign lesions (P < .001). Vascular grades were significantly higher in HCC lesions than benign lesions in nearly all cases, although the corresponding area under the curve values were relatively low, at 0.54 to 0.59 for the central vessel grades and 0.63 to 0.64 for the peripheral vessel grades.

CONCLUSIONS

More central and peripheral vessels were found around liver lesions on SMI than on CFD and PD imaging. Although there was significantly more vascularity on the periphery of malignant liver lesions than benign lesions, the overall diagnostic performance based on this criterion alone was relatively low, with an area under the curve of 0.64.

The Sonographic Stenosis Index: A New Specific Quantitative Measure of Transplant Hepatic Arterial Stenosis

OBJECTIVES

This study evaluates the sensitivity and specificity of stenosis index (SI), which accounts for the entire spectral Doppler waveform, to detect significant transplant hepatic arterial stenosis.

MATERIALS AND METHODS

In this institutional review board-approved, HIPAA compliant study, we retrospectively analyzed 69 patients who had catheter angiography for suspected transplant hepatic arterial stenosis (THAS) between January 2006 and December 2010; all patients had Doppler ultrasound within 30 days before angiography. Patients with angiographic stenosis requiring intervention were considered positive for THAS. Stenosis index was calculated from each patient's spectral Doppler ultrasound images by obtaining the ratio of the area under the high-frequency signal to low-frequency signal in the spectral Doppler. Resistive index (RI) and pulsatility index (PI) were also calculated. Receiver operator curve analysis was performed and the area under the curve (AUC) was compared among the three metrics.

RESULTS

Forty-eight of 69 patients had THAS by angiography requiring intervention; 21patients had no angiographic evidence of THAS. SI was significantly different (P < .001) between patients with THAS (SI = 1.04 ± 0.20) and those without THAS (SI = 1.39 ± 0.30). Stenosis index had an AUC of 0.86 for detecting THAS, which was significantly higher than that from RI (AUC = 0.68, P = .038 for the comparison) and PI (AUC = 0.70, P = .029). For SI < 1.35, the sensitivity for THAS was 94% and specificity was 52%. For RI < 0.5, the sensitivity was 96% and the specificity was 29%.

CONCLUSIONS

Stenosis index is more accurate than the resistive index and the pulsatility index for detecting transplant hepatic artery stenosis.

Increased fetal lung T2 signal is not due to increasing surfactant concentration: an in vitro T2 mapping analysis

OBJECT

The aim of this study was to perform in vitro T2 mapping of serial dilutions of pharmaceutical surfactant.

MATERIALS AND METHODS

Magnetic resonance imaging. Magnetic resonance scanning was performed on serial dilutions of surfactant on large bore clinical magnets at a field strength of 1.5 T Philips and 3.0 T (Achieva TX, Philips Healthcare, the Netherlands).

RESULTS

The curves demonstrate a small increasing trend between surfactant concentration and R2 (shortened T2's), with a 7.3% increase in R2 for each doubling of surfactant concentration (95% confidence interval: 6.1-8.6%, p < 0.001).

CONCLUSIONS

The increasing lung/liver T2 signal ratio seen in fetal lungs with increasing gestational age is not due to increasing surfactant concentration. © 2016 John Wiley & Sons, Ltd.

Ovarian Torsion in a Teenage Girl with Genitourinary Anomaly

We present the clinical presentation, sonography, CT, and MR imaging as well as correlative intra-operative and gross pathological findings of ovarian torsion in a 14-year-old girl. Our findings are discussed in the context of prior imaging studies performed for the evaluation of ovarian torsion. Ovarian torsion is not an uncommon cause of acute abdominal pain in children and teenage girls. Diagnosis of this entity can be difficult based on clinical presentation or on imaging appearance alone.

Comprehensive imaging review of abnormalities of the umbilical cord

A complete fetal ultrasonographic (US) study includes assessment of the umbilical cord for possible abnormalities. Knowledge of the normal appearance of the umbilical cord is necessary for the radiologist to correctly diagnose pathologic conditions. Umbilical cord abnormalities can be related to cord coiling, length, and thickness; the placental insertion site; in utero distortion; vascular abnormalities; and primary tumors or masses. These conditions may be associated with other fetal anomalies and aneuploidies, and their discovery should prompt a thorough fetal US examination. Further workup and planning for a safe fetal delivery may include fetal echocardiography and karyotype analysis. Doppler US is a critical tool for assessment and diagnosis of vascular cord abnormalities. US also can be used for follow-up serial imaging evaluation of conditions that could result in fetal demise. Recent studies suggest that three- or four-dimensional Doppler US of the fetal umbilical cord and abdominal vasculature allows more accurate diagnosis of vascular abnormalities. Doppler US also is invaluable in assessment of fetal growth restriction since hemodynamic changes in the placenta or fetus would appear as a spectral pattern of increased resistance to forward flow in the fetal umbilical artery. Early detection of umbilical cord abnormalities and close follow-up can reduce the risk of morbidity and mortality and assist in decision making.

Evaluation and management of disorders of sex development: multidisciplinary approach to a complex diagnosis

Various disorders of sex development (DSD) result in abnormal development of genitalia, which may be recognized at prenatal ultrasonography, immediately after birth, or later in life. Current methods for diagnosing DSD include a thorough physical examination, laboratory tests to determine hormone levels and identify chromosomal abnormalities, and radiologic imaging of the genitourinary tract and adjacent organs. Because of the complex nature of DSD, the participation of a multidisciplinary team is required to address the patient's medical needs as well as any psychosocial issues that the patient or the family may encounter after the diagnosis. The first step in the management of DSD is sex assignment, which is based on factors such as the genotype; the presence, location, and appearance of reproductive organs; the potential for fertility; and the cultural background and beliefs of the patient's family. The primary goal of sex assignment is to achieve the greatest possible consistency between the patient's assigned sex and his or her gender identity. Once the sex is assigned, the next step in management might be surgery, hormone therapy, or no intervention at all. Patients with ovotesticular DSD and gonadal dysgenesis may require a gonadectomy, followed by reconstructive surgery. Some patients may need hormone replacement therapy during puberty. An understanding of the immediacy of families' need for sex assignment and clinicians' need for reliable diagnostic imaging results will help radiologists participate effectively in the prenatal and postnatal assessment of patients with DSD.

Pre-operative CT angiography and three-dimensional image post processing for deep inferior epigastric perforator flap breast reconstructive surgery

Autologous breast reconstructive surgery with deep inferior epigastric artery (DIEA) perforator flaps has become the mainstay for breast reconstructive surgery. CT angiography and three-dimensional image post processing can depict the number, size, course and location of the DIEA perforating arteries for the pre-operative selection of the best artery to use for the tissue flap. Knowledge of the location and selection of the optimal perforating artery shortens operative times and decreases patient morbidity.

Imaging of uncommon retroperitoneal masses

Retroperitoneal masses not arising from major solid organs are uncommon. Although there is no simple method of classifying retroperitoneal masses, a reasonable approach is to consider the masses as predominantly solid or cystic and to subdivide these into neoplastic and nonneoplastic masses. Because the treatment options vary, it is useful to be able to differentiate these masses by using imaging criteria. Although the differential diagnosis of retroperitoneal masses can be narrowed down to a certain extent on the basis of imaging characteristics, patterns of involvement, and demographics, there is still a considerable overlap of imaging findings for these masses, and histologic examination is often required for definitive diagnosis. Computed tomography (CT) and magnetic resonance (MR) imaging play an important role in characterization and in the assessment of the extent of the disease and involvement of adjacent and distant structures. Familiarity with the CT and MR imaging features of various retroperitoneal masses will facilitate accurate diagnosis and staging for aggressive lesions.

Prospective versus retrospective ECG gating for 64-detector CT of the coronary arteries: comparison of image quality and patient radiation dose

PURPOSE

To compare image quality and patient radiation dose in a group of patients who underwent 64-detector computed tomography (CT) coronary angiography performed with prospective electrocardiographic (ECG) gating with image quality and radiation dose in a group of patients matched for clinical features who underwent 64-detector CT coronary angiography performed with retrospective ECG gating.

MATERIALS AND METHODS

Institutional review board approval was obtained for this HIPAA-compliant study, and the informed consent requirement was waived due to the retrospective study design. Two independent reviewers separately scored coronary artery segment image quality and overall image quality for 100 cardiac CT studies (50 in each group). Interobserver variability was calculated. Patient radiation dose for the actual examination z-axis length was recorded, and a normalized dose was calculated for a 12-cm z-axis length of a typical heart.

RESULTS

The two groups matched well for clinical characteristics and CT parameters. There was good agreement for coronary artery segment image quality scores between the independent reviewers (kappa = 0.72). Of the 1253 coronary artery segments scored, the number of coronary artery segments that could not be evaluated in each group was similar (1.1% [seven of 614] in the prospective group vs 1.5% [10 of 647] in the retrospective group, P = .53). Image quality scores were not significantly different when matched for chest cross-sectional area (P > .05). Mean patient radiation dose was 77% lower for prospective gating (4.2 mSv) than for retrospective gating (18.1 mSv) (P < .01).

CONCLUSION

Use of 64-detector CT coronary angiography performed with prospective ECG gating has similar subjective image quality scores but 77% lower patient radiation dose when compared with use of retrospective ECG gating.

Differential diagnosis of thyroid nodules with US elastography using carotid artery pulsation

PURPOSE

To explore the sensitivity and specificity of ultrasonographic (US) elastography using carotid arterial pulsation as the compression source for differential diagnosis of thyroid nodules.

MATERIALS AND METHODS

This HIPAA-compliant study was approved by the ethics committee of the institution, and all patients provided written informed consent. Fifty-eight patients (13 men and 45 women [mean age, 51 years; range, 20-76 years]) were enrolled. A short US examination and elastography with pulsation of the carotid artery used as the thyroid compression source were performed before fine-needle aspiration. Baseband US data were downloaded for off-line analysis. Elastographic maps and the thyroid stiffness index were calculated. The Kruskal-Wallis nonparametric rank sum test was used to assess equality of population medians among the different types of thyroid nodules; the R software environment was used for statistical computing and graphics (http://www.r-project.org/).

RESULTS

Thyroid stiffness index calculated with elastography using carotid arterial pulsation as the compression source was effective in helping distinguish between papillary carcinomas (n = 10) and other lesions (n = 43) because papillary carcinomas were stiffer than other lesions (P < .0039).

CONCLUSION

It is possible to distinguish between papillary carcinomas and other lesions with the thyroid stiffness index calculated from US elastography using carotid arterial pulsation.

Ultrasound-based elastography: a novel approach to assess radio frequency ablation of liver masses performed with expandable ablation probes: a feasibility study

OBJECTIVE

The purpose of this study was to evaluate the technical feasibility of ultrasound-based elastography as a tool for assessing the size and shape of the coagulation necrosis caused by radio frequency ablation (RFA) probes using expandable electrodes ex vivo as well as in a patient with a liver metastasis.

METHODS

A commercially available expandable RFA probe was used to create a 3-cm ablation in a piece of bovine liver. The ablation probe was used in situ to induce tissue deformation for elastography before and after ablation. Ultrasonic radio frequency data were processed to generate elasticity strain images. The appearance of the ablation zone was compared with magnetic resonance imaging and a gross section specimen. One patient with malignant metastatic disease to the liver and a clinical indication for RFA was investigated for the feasibility of percutaneous elastography of RFA using the same technique. Sonographic strain images were compared with the appearance of the nonenhancing ablation zone on contrast-enhanced computed tomography.

RESULTS

Ex vivo, the ablation zone on ultrasound-based elastography was represented by an area of increased stiffness and was well demarcated from the nonablated surrounding tissue. The size and shape of the ablated zone on the strain image correlated well with the gross specimen and the magnetic resonance imaging appearance. Strain images obtained from the patient showed results similar to those of the ex vivo experiment and correlated well with the nonenhancing area of ablation on contrast-enhanced computed tomography.

CONCLUSIONS

Ultrasound-based elastography may be a promising tool for displaying the ablation zone created by expandable RFA probes.

Reimaging the female pelvis with ultrasound after CT: general principles

Ultrasound is the most appropriate first imaging test to perform when gynecologic pathology is suspected based on clinical history or physical examination, and imaging is required. However, as a practical matter, a woman's first imaging test evaluating her pelvis may be a computed tomographic (CT) scan; this is especially true when these women present to an acute care facility or emergency department with chronic or acute lower abdominal pain. Radiologists need to be able to recognize the CT features of a variety of gynecologic conditions. However, just as importantly, radiologists should have a firm understanding of general principles that help to clarify when reimaging the pelvis with ultrasound is indicated; furthermore, a clear understanding of these principles helps to focus the sonologist's attention on the sonographic features that will be most helpful in further characterization of abnormal CT findings. This pictorial essay discusses these general principles that clarify when ultrasound is and is not helpful in reimaging the female pelvis after CT.

Computed Tomographic and Magnetic Resonance Features of Gynecologic Abnormalities in Women Presenting With Acute or Chronic Abdominal Pain

Advances in technology and improved availability have led to increased use of computed tomography (CT) and magnetic resonance imaging (MRI) to evaluate women presenting to the emergency department or to their primary care provider with abdominal and/or pelvic pain. Computed tomographic examinations are often performed to evaluate the presence of appendicitis or renal stone disease. However, gynecologic abnormalities are frequently identified on these examinations. Although ultrasound remains the primary modality by which complaints specific to the pelvis are evaluated, in many instances, CT and MRI imaging occurs before sonographic evaluation.Historically, because of cost, radiation exposure, and relative ease of use, ultrasound examinations have preceded all other imaging modalities when evaluating pelvic disorders. However, as CT and MRI technology have improved, their use in diagnosing causes of pelvic pain has become equal to that of ultrasound. In some cases, primarily because of historic comfort with sonographic evaluation, gynecologic abnormalities originally diagnosed on CT or MRI may be immediately and unnecessarily reevaluated by ultrasound. For a woman in her reproductive years, the most common adnexal masses are physiological cysts, endometriomas, and cystic teratomas. Although lesions are often asymptomatic and incidentally detected, they can present with pain, and they increase the risk of ovarian torsion. Common causes of chronic pelvic pain in this population include leiomyomata and adenomyosis. In postmenopausal women, ovarian carcinoma, which often does not present clinically until a late stage, has to be included in the differential diagnosis of adnexal masses. If a gynecologic pathology is discovered on CT or MRI, an immediate follow-up ultrasound need not be pursued if the lesion can be characterized as benign, needing immediate surgical intervention, or a variant of normal anatomy. If, on the other hand, findings demonstrate a mass that either is uncharacteristic of a benign lesion, has an indeterminate risk for malignancy, or demonstrates suspicious characteristics for malignancy (such as enhancing mural nodules), further evaluation by serial ultrasound, biochemical marker, and/or CT or MRI is warranted. The purpose of this review is to present a series of commonly encountered gynecologic abnormalities with either CT or MR to make radiologists more familiar with gynecologic pathology on CT and MRI.

Myocardial infarction on non-ECG synchronized contrast-enhanced multi-detector computed tomography

To demonstrate that myocardial infarctions can be visualized on non-ECG-synchronized, contrast-enhanced multidetector computed tomography (MDCT). Myocardial infarctions are visible on contrast-enhanced MDCT scans even when cardiac gating is not utilized. Focusing on myocardial enhancement should allow radiologists to play a greater role in the evaluation of cardiac disease.

Value of sonography in the diagnosis of abnormal vaginal bleeding

Abnormal vaginal bleeding is one of the most common presenting complaints in women of any age seeking gynecologic health care. Two of the most frequently used diagnostic tests to investigate the cause of the bleeding are endometrial biopsy and transvaginal sonography. The most worrisome cause of abnormal bleeding is endometrial carcinoma, yet benign etiologies are far more prevalent, including fibroids, polyps, and endometrial atrophy. Endometrial biopsy and transvaginal sonography have equal sensitivities for carcinoma, but sonography is far more effective in diagnosing benign disease. This article reviews the state-of-the-art in the diagnostic evaluation of abnormal vaginal bleeding and analyzes the data, with emphasis on the prevalence of benign and malignant disease as the basis for determining whether sonography or biopsy is more cost-effective in evaluating women with abnormal vaginal bleeding.

Acute myocardial infarction demonstrated by multidetector CT scanning

A 55-year-old man was brought to the emergency room complaining of left-sided chest pain. His electrocardiogram was indeterminate, and a multidetector computed tomogram (MDCT) was performed to exclude aortic dissection. The patient's aorta was normal, but an area of hypoperfusion was evident in the lateral ventricular myocardial wall. The ability to diagnose myocardial ischemia and infarcts on nongated MDCT is of particular clinical interest. As more imaging technology is devoted to imaging the heart, the greater expectations of radiologists' ability to diagnose cardiac disease in the emergency room will become.

Cost-effectiveness model for first-trimester versus second-trimester ultrasound screening for down syndrome

PURPOSE

To develop a cost-effectiveness analysis model from the perspective of Medicare reimbursement to evaluate the costs and potential risks involved in performing second-trimester genetic sonography following the first-trimester sonographic measurement of nuchal translucency and serology for Down syndrome screening.

METHODS

Three clinical screening algorithms were constructed that detailed the diagnostic evaluation of the target population by using first-trimester or second-trimester ultrasound and appropriate serologies or first-trimester and second-trimester screening in combination. The cost analysis was then created by using a computer spreadsheet program by applying Medicare reimbursement, the prevalence of Down syndrome, and reported sensitivities of first-trimester and second-trimester ultrasound and analytes for Down syndrome for each clinical algorithm. Medicare Current Procedural Terminology codes, total relative value units, and payments for first-trimester and second-trimester ultrasound, chorionic villous sampling, amniocentesis, and serum analytes were obtained from the Medicare Part B Washington 2002 Provider Disclosure Report.

RESULTS

At any given prevalence of Down syndrome, first-trimester screening is always slightly less expensive to society than the other two models for both total cost and cost to diagnose each case of Down syndrome. Even if second-trimester screening were 100% sensitive, the sensitivity of first-trimester screening would have to fall below 55% for model 2 to be cheaper than model 1. Combining both first-trimester and second-trimester screening was substantially more expensive than models 1 or 2. More iatrogenic fetal deaths occur with combined screening than with either first or second trimester screening alone.

CONCLUSIONS

Screening using first-trimester ultrasound and serologic markers to screen for Down syndrome is always slightly less expensive to society than second-trimester serologic and ultrasound screening. However, there is a significantly increased risk for iatrogenic fetal death if second-trimester genetic sonography is performed following normal first-trimester screening using currently accepted risk ratios. Patients should be counseled appropriately with this information, because an individual's circumstances will affect that person's perception of risk and subsequently affect his or her decision making.

Rotator cuff ultrasonography: diagnostic capabilities

Dynamic shoulder ultrasonography is a noninvasive, accurate method used to assess the rotator cuff tendons. It can be incorporated into the in-office physical examination of patients at risk for rotator cuff problems. The low cost, convenience, and lack of risk make dynamic ultrasonography an excellent imaging tool for evaluating the biceps, subscapularis, infraspinatus, teres minor, and supraspinatus tendons. In-office ultrasound also provides an opportunity for patient education and explanation of management options.

Ultrasonographic evaluation of the endometrium in postmenopausal vaginal bleeding

Transvaginal ultrasound with SIS is a cost-minimizing screening tool for perimenopausal and postmenopausal women with vaginal bleeding. Its use decreases the need for invasive diagnostic procedures for women without abnormalities, and ultrasound increases the sensitivity of detecting abnormalities in women with pathologic conditions. Vaginal sonography is preferred over uniform biopsy of postmenopausal women with vaginal bleeding because it (1) is a less invasive procedure, (2) is generally painless, (3) has no complications, and (4) may be more sensitive for detecting carcinoma than blind biopsy. Transvaginal sonography is rarely nondiagnostic. Endometrial sampling is less successful in women with a thin endometrial stripe on ultrasound than in women with real endometrial pathologic condition. A limitation of ultrasound is that an abnormal finding is not specific: ultrasound cannot always reliably distinguish between benign proliferation, hyperplasia, polyps, and cancer. Although ultrasound may not be able to distinguish between hyperplasia and malignancy, the next step in the clinical treatment requires tissue sampling. Because of the risk of progression of complex hyperplasia to carcinoma, patients with this finding may benefit from hormonal suppression, dilatation and curettage, endometrial ablation, or hysterectomy, depending on the clinical scenario. The inability to distinguish these two entities based on ultrasound alone should not be seen as a limitation because tissue sampling is required in either case. Occasionally (in 5% to 10% of cases), a woman's endometrium cannot be identified on ultrasound, and these women also need further evaluation. Ultrasonography also may be used as a first-line investigation in other populations with abnormal uterine bleeding. In a multicenter, randomized, controlled trial of 400 women with abnormal uterine bleeding, the investigators found that transvaginal sonography combined with Pipelle endometrial biopsy and outpatient hysteroscopy was as effective as inpatient hysteroscopy and curettage. The subject, included women older than 35 years with PMB, menorrhagia, intermenstrual bleeding, postcoital bleeding, or irregular menses. Transvaginal sonography may be a cost-effective. sensitive, and well-tolerated method to evaluate most women with abnormal bleeding in combination with physical examination and endometrial biopsy and hysteroscopy us indicated. Hysteroscopy is likely to become the new gold standard in the future because of its ability to visualize directly the endometrium and perform directed biopsies as indicated. As office-based hysteroscopy becomes more practical and widespread, the technique may become more cost effective. An evaluation plan using transvaginal sonography as the initial screening evaluation followed by endometrial biopsy or, more likely, hysteroscopy is likely to become the standard of care (Fig. 12). It remains unproven whether certain patients at higher risk for carcinoma should proceed directly to invasive evaluation. Women on tamoxifen with persistent recurrent bleeding, women with significant risk factors for carcinoma, and women with life-threatening hemorrhage comprise this group. Further studies are still necessary to evaluate high-risk patients and determine whether ultrasound or biopsy is really the most cost-effective initial test.

Association of shoulder sonographic findings with subsequent surgical treatment for rotator cuff injury

OBJECTIVE

To identify any clinical and radiologic findings of rotator cuff injury that predict whether patients will undergo shoulder surgery.

METHODS

We retrospectively studied all shoulder sonograms obtained at a single institution over 12 months. Possible predictors of surgical treatment were documented, including patient age and sex, duration and types of symptoms, and the location and severity of tendon damage on sonography. One hundred twenty-eight patients underwent shoulder sonography; 34 patients eventually underwent shoulder surgery. Multivariate logistic regression was performed to identify clinical and sonographic factors associated with the use of surgical therapy.

RESULTS

The only statistically significant predictor of surgical intervention was the finding of full-thickness tears (with or without tendon retraction) on sonography (P = .03). Patients with full-thickness tears were 4.3 times more likely to undergo surgery than those with no tears (odds ratio, 4.3).

CONCLUSIONS

The sonographic diagnosis of full-thickness rotator cuff tears is the only finding statistically associated with the use of surgical treatment. No single clinical variable was consistently associated with subsequent surgery. Partial-thickness tears on sonography also do not show any statistical association with the eventual use of surgery for rotator cuff symptoms.

Intracervical sonographic-pathologic correlation: preliminary results

OBJECTIVE

To determine whether current-generation endoluminal ultrasonic transducer technology could visualize dysplastic and malignant cervical lesions.

METHODS

Inclusion criteria for patients enlisted in the study were abnormal Papanicolaou test results, an abnormality seen at colposcopy, and consent for a cone biopsy. In addition, we included 4 women who were undergoing hysterectomy but had no evidence of cervical abnormalities at the time of surgery, for a total of 28 women. We used a 20-MHz annular array intravascular transducer. We correlated all sonographic and pathologic results with regard to being normal or abnormal using the Pearson product moment correlation coefficient, and we evaluated interobserver variation by having 5 blinded sonologists interpret each examination and calculating kappa statistics.

RESULTS

We performed intracervical sonography on 24 women with abnormal Papanicolaou test results and on 4 women without abnormalities. Nineteen of the 24 women with proven disease had abnormal sonographic images. Five women with pathologically proven cervical intraepithelial neoplasia I had normal sonographic images. Lesions ranged in size from 0.3 to 7 mm. Two carcinomas (5 and 7 mm diameter), multiple nabothian cysts, cervicitis, and 2 giant cell foreign body reactions were visible on sonography. The correlation coefficient for abnormal sonographic and pathologic findings was 0.87 (P < .005). We obtained a kappa value of 0.75 for interobserver variation.

CONCLUSIONS

Intracervical sonography was able to visualize dysplastic lesions and carcinomas as hypoechoic defects with surrounding echogenic areas of glandular cervical mucosa. Lesions were shown with sufficient resolution and interobserver variation to suggest that the technique may be clinically applicable, particularly for planning surgical therapy. However, design of a transducer that can be easily sterilized between examinations, similar to current endovaginal probes, would be necessary to make intracervical sonography a clinically feasible examination.

Cost analysis model: US versus endometrial biopsy in evaluation of peri- and postmenopausal abnormal vaginal bleeding

PURPOSE

To develop a cost minimization analysis model from the societal perspective of Medicare reimbursement to determine whether endometrial biopsy or transvaginal ultrasonography (US) is less expensive in evaluating peri- and postmenopausal women with abnormal vaginal bleeding and to assess whether this strategy is equally effective in populations at low and high risk for endometrial carcinoma.

MATERIALS AND METHODS

Clinical algorithms were constructed that detailed diagnostic evaluation of the target population by using office-based endometrial biopsy versus transvaginal US as starting points. An economic model based on Medicare reimbursement and average wholesale drug price data and using disease prevalences and modality sensitivities from the scientific literature was then created to examine common bleeding causes in this population. All models included the cost of obtaining a tissue diagnosis for focal or diffuse endometrial thickening found at US. Modality sensitivities and prevalences of disease states were varied within the model to discover limits at which each modality became cheaper versus the other for assessing a population of women.

RESULTS

Population prevalence of neoplastic disease is the principal factor governing total cost between competing diagnostic algorithms. In populations with 31% or less combined prevalence of endometrial carcinoma/atypical adenomatous hyperplasia, algorithms utilizing transvaginal US as the initial test are most cost minimizing. At combined endometrial carcinoma/atypical adenomatous hyperplasia prevalence of 10%, savings of up to 11% and 16% over pathways initiated with endometrial biopsy are predicted. In populations with a high incidence of neoplastic disease (>31%), biopsy-based algorithms should become least costly.

CONCLUSION

Transvaginal US-initiated triage predicts substantial cost savings versus biopsy-based algorithms in evaluating typical populations of peri- and postmenopausal women with abnormal vaginal bleeding seen in clinical practice.

Low-resistance endometrial arterial flow in the exclusion of ectopic pregnancy revisited

The objective of this study was to evaluate the efficacy of endometrial arterial flow in the exclusion of ectopic pregnancy. From October 1997 to June 1999, 66 women with elevated beta-human chorionic gonadotropin titers and clinical indications of ectopic pregnancy were evaluated by endovaginal sonography. Women with a gestational sac containing an embryo, a yolk sac, or both were excluded from the study. Doppler ultrasonography was performed in the remaining cases when a definite intrauterine pregnancy could not be visualized. In all cases the thermal index was kept to less than 1.0, consistent with as-low-as-reasonably-achievable principles. Trophoblastic flow was defined as a resistive index of less than 0.6 within the endometrium. Statistical analysis was performed using a 2-tailed t test. Twenty women had ectopic pregnancies; 33 had spontaneous pregnancy losses; and 13 had normal intrauterine pregnancies. A total of 29 women had endometrial trophoblastic flow: 11 of 13 with intrauterine pregnancies, 1 of 20 with ectopic pregnancies, and 17 of 33 with spontaneous pregnancy losses. The negative predictive value for the presence of endometrial low-resistance flow for excluding ectopic pregnancy was 97%. The presence of low-resistance arterial endometrial flow can be a useful sign in diagnosing an early intrauterine pregnancy and decreasing the probability that an ectopic pregnancy is present, particularly in patients with otherwise normal ultrasonographic findings.