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Objectives The growing body of evidence suggesting that lifestyle changes and aggressive medical management reduce the risk of strokes in patients with carotid stenosis has fostered interest in noninvasive screening. The objective of this study was to develop recommendations for follow-up carotid ultrasound surveillance of patients with Methods This retrospective observational cohort study includes 2956 patients seen between August 1998 and March 2015 in 4440 visits. Data analysis was restricted to 7710 carotid ultrasounds. Primary outcome was progression of carotid stenosis as defined by the “bulb” method: baseline stenosis of 0%–39% progressed to 40%–59% on subsequent examination, baseline stenosis of 0%–39% progressed to ≥60%, or baseline of 40%–59% progressed to ≥60%. Progression was estimated using Cox proportional hazard ratios and the Kaplan-Meier method. Results More than 10% of patients progressed in the 40%–59% baseline group within 12 months compared to 78 months for the 0%–39% baseline group. Patients who progressed had a higher proportion of peripheral vascular disease, and current/former smoking compared to those who did not. While there were statistically significant correlations between medication classes and comorbidities, none of the medications studied appeared to slow carotid stenosis progression. Conclusions In our experience, for patients with a 0%–39% carotid stenosis, follow-up examination should be performed at 6-year intervals. For patients with 40%–59% carotid stenosis, follow-up should be obtained annually to identify those who progress to a level requiring intervention. Future studies should examine whether study findings can be replicated using other approaches for determining carotid stenosis.

Hepatorenal index (HRI) has been shown to be an effective, noninvasive ultrasound tool to screen patients for those with or without >5% hepatic steatosis. Objective: The aim of this study was to further refine this HRI tool in order to stratify patients according to their degree of liver steatosis and give direction as to which patients should undergo random liver biopsy. Methods: We conducted a retrospective review of 267 consecutive patients from 2015 to 2017 who had abdominal ultrasounds and a subsequent random liver biopsy within one month. The HRI was calculated and compared with the percent steatosis as assessed by histology. Results: An HRI of ≤1.17 corresponds with >95% positive predictive value of ≤5% steatosis. Between HRI values 1.18 and 1.39, performance of steatosis prediction is mixed. However, for values 1.37. An HRI of ≥1.4 corresponds with >95% positive predictive value of ≥10% steatosis. Conclusion: HRI is an accurate noninvasive tool to quantify degree of steatosis and guide who should undergo random liver biopsy, potentially significantly reducing the total number of necessary liver biopsies.

Objectives-The purpose of this study was to determine the incidences and rates of progression of varying degrees of carotid stenosis that do not require intervention according to the Asymptomatic Carotid Atherosclerosis Study, the European Carotid Surgery Trial, and the North American Symptomatic Carotid Endarterectomy Trial, and from this information, to provide evidence-based recommendations for follow-up imaging.

Objectives We sought to assess midterm sonographic findings in patients after stenting for hepatic artery stenosis. Methods Thirty-nine hepatic artery stent procedures were performed for hepatic artery stenosis after liver transplantation between September 2009 and December 2013. Thirty cases were technically successful and met the minimum follow-up time (76 days, defined by earliest diagnosed stenosis). Routine ultrasound surveillance was obtained on all patients, and statistical analysis of the findings in the patency and restenosis groups was performed. Results Of the 30 cases, restenosis occurred 9 times in 6 patients. Mean follow-up was 677 days. Mean time to restenosis was 267 days. Five cases (56%) were identified within the first 6 months after stent placement. Four cases (44%) were recognized in the second year after stent placement. Prior to the sonographic diagnosis of restenosis, the mean resistive indices of the main (.64 versus .57, P

Radiologists are faced with ever-increasing challenges in the needs of the practice, in both private and academic settings. Targeted information about protecting and maintaining the physical, mental, and emotional health of the radiologist is highly limited. Impairment is a functional classification that implies that the individual affected by a disease is unable to perform specific activities. Radiologists can suffer from the same illnesses as any human being, which include substance abuse and addiction, as well as chronic infectious diseases such as human immunodeficiency virus, hepatitis B and C, and tuberculosis. This article is intended to educate radiologists and leaders about various forms of physician impairment. It provides discussion of the challenges related to such impairment and provides tools and resources to address the impaired radiologist.

Practice leaders surveyed in the 2017 ACR Human Resources Commission workforce survey reported that 25% of the radiologists or radiation oncologists they supervised had neck pain, 32% had low back pain, and 16% were dealing with a repetitive stress injury. The prevalence rates of these musculoskeletal ailments among radiologists and radiation oncologists were consistent with those reported in the literature in other populations. However, these prevalence rates may be underestimated because practice leaders, not the radiologists themselves, were surveyed, and the leaders may not be aware of all injuries.

BackgroundHepatic artery stenosis (HAS) after orthotopic liver transplantation is a significant risk factor for subsequent hepatic artery thrombosis (HAT). HAT is associated with a 30%-50% risk of liver failure culminating in retransplantation or death. Traditional treatment of hepatic artery complications has been surgical, with hepatic artery revision or retransplantation. Endovascular therapy of HAS, described primarily in the interventional radiology literature, may provide a less-invasive treatment option.MethodsThis was a retrospective review of all endovascular interventions performed for HAS after orthotopic liver transplantation over a 31-month period (August 2009 to January 2012). Patients with duplex ultrasound imaging evidence of severe main HAS (peak systolic velocity of >400 cm/s, resistive index of

OBJECTIVE. The risk of injury associated with long-term occupational exposure to ionizing radiation is low for radiologists. The purpose of this article is to systematically review and inform radiologists about radiation-related effects to which they are potentially susceptible. CONCLUSION. Formal education and training on radiation safety and management, careful attention to good radiation protection habits, and continued emphasis on radiation management and the as low as reasonably achievable principle are recommended for all radiologists.

Objectives— The purposes of this study were to develop a protocol for evaluating pancreas allografts, to describe a method for successfully studying pancreatic transplants, and to determine whether the resistive index (RI) of the splenic artery is a useful differentiator between complications.Methods— We retrospectively analyzed clinical, surgical, procedural, and radiologic reports in 51 consecutive patients undergoing 182 sonographic examinations during a 4.5-year period. Complications included splenic vein thrombosis, rejection, and pancreatitis. We obtained RIs in normal and complication groups and performed mixed model regression methods and receiver operating characteristic analysis.Results— The mean RI ± SD for normal transplants was 0.65 ± 0.09; for splenic vein thrombosis, 0.76 ± 0.09; after resolution of splenic vein thrombosis, 0.73 ± 0.09; during rejection, 0.94 ± 0.09; after successful treatment of rejection, 0.74 ± 0.09; for pancreatitis, 0.83 ± 0.09; and for fluid collections, 0.66 ± 0.09. There was a statistically significant difference (P < .05) between normal transplants and splenic vein thrombosis (P = .0003), rejection (P < .0001), and pancreatitis (P = .04). A significant difference was also seen between rejection and successful treatment thereof (P < .0001).Conclusions— We developed a protocol that allowed us to successfully evaluate 96% of the pancreatic allografts studied. Furthermore, our data show that the RI can be used as a therapeutic guide. When the RI is less than 0.65, the risk of vascular abnormalities is very low; however, fluid collections may be present. When greater than 0.75, splenic vein thrombosis, pancreatitis, or rejection should be suspected. When greater than 0.9, rejection must be seriously considered.

Stroke accounts for a significant degree of morbidity, mortality, and health care expenditure in this nation despite the many medical and surgical preventive measures we have in place. This article discusses how developing a universally accepted effective screening examination will help decrease this health care burden. Risk factors for the development of cardiovascular disease are explored. Special attention is given to the pathogenesis and diagnosis of carotid atherosclerosis because it accounts for a large percentage of both embolic and ischemic strokes. Current diagnostic testing, in particular duplex carotid sonography, and proposed screening strategies for the detection of carotid atherosclerosis and other risk factors are reviewed. Sex-related differences proposed in the current literature are also explored in this article because they may affect how we screen for and prevent stroke.Developing an accurate, cost-effective, and universally acknowledged screening test will allow us to maximize the preventive medical and surgical measures we already have in place. Doing so will in turn lead to a significant decrease in the morbidity, mortality, and health care expenditure associated with stroke.

The objective of this study was to prospectively evaluate the use of point shear wave elastography for the assessment of liver fibrosis and to determine the usefulness and optimal location for obtaining elastography measurements in native and transplanted livers. Point shear wave elastography measurements were obtained from 100 consecutive patients presenting for percutaneous liver biopsy. Measurements were acquired within both the superior right hepatic lobe (segments VII/VIII) via an intercostal approach and the inferior right hepatic lobe (segments V/VI) via a subcostal approach. Analysis of variance was used to assess statistical differences between the degree of fibrosis on percutaneous liver biopsy and elastography measurements. No statistical difference was present when comparing elastography measurements in patients with hepatic steatosis compared with patients without steatosis (P = 0.2759). There was no difference in the accuracy of elastography measurements in native livers versus transplanted livers (P = 0.221). Point shear wave elastography can accurately differentiate between patients with no-to-mild hepatic fibrosis (F0-F1) and moderate-to-severe hepatic fibrosis (≥F2) with sensitivity of 72% and specificity of 69%. Point shear wave elastography can be used as a noninvasive method to assess fibrosis in patients with native or transplanted livers. In addition, measurements can be combined or taken separately from either the superior or inferior right hepatic lobe. The presence of hepatic steatosis does not affect the accuracy of point shear wave elastography. However, shear wave elastography values in patients with body mass index greater than 40 should be interpreted with caution.

Objectives-Marshall et al (AJR Am J Roentgenol 2012; 199:997-1002) initially demonstrated that the hepatorenal index is an effective and noninvasive tool to screen patients for hepatic steatosis. The aim of this study was to determine whether the hepatorenal index can be accurately calculated directly from a picture archiving and communication system (PACS) quickly and efficiently without the need for the multiple steps and specialized software used to calculate hepatorenal index in the study by Marshall et al. Methods-We evaluated 99 of the 101 patients included in the study by Marshall et al: patients being followed by hepatologists with plans for liver biopsy. The hepatorenal index was calculated by using Digital Imaging and Communications in Medicine (DICOM) images from a PACS and a markup region-of-interest tool. We compared this value to the value that Marshall et al derived by using specialized software and to standard histologic estimates. We created similar subgroups: patients with steatosis based on histologically estimated intracellular fat exceeding 5% and patients without steatosis. Results-The mean hepatorenal index ± SD for those with steatosis according to histologic findings was 1.87 ± 0.6, and for those without, it was 1.14 ± 0.2. A hepatorenal index of 1.34 or higher had 92% sensitivity for identifying fat exceeding 5%, 85% specificity, a 94% negative predictive value, and a 79% positive predictive value. Substantial agreement was found between the hepatorenal index calculated from DICOM images and macrovesicular fat categorized at the cut point of 1.34 or higher (? = 0.76; 95% confidence interval, 0.62-0.88; P < .001). Conclusions-The hepatorenal index can be quickly and accurately calculated from DICOM images directly on a PACS without supplementary software.

n important first step in the workup of a patient with a palpable testicular mass is sonography, considered by some to be an extension of the physical examination.1 Sonographic accuracy in the determination of intratesticular versus extratesticular masses has been reported as high as 99%.2 This distinction is important because most intratesticular masses prove to be malignant.3 Benign causes of intratesticular masses include hematoma, orchitis, torsion, infarction, and abscesses.4 The case presented had an unusual cause of an intratesticular mass.

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.

Objective. To describe the importance of obtaining erect views when evaluating the celiac artery with sonography. Methods. Two patients had duplex and color flow Doppler sonographic evaluations of the celiac artery, including inspiration, expiration, and erect views. Results. Both patients had elevated celiac artery velocities with inspiration and expiration. These results alone would suggest celiac artery stenosis. With erect views, the celiac artery velocities returned to normal. The addition of erect views allowed the correct diagnosis of median arcuate ligament syndrome to be made. Conclusions. When evaluating the celiac artery, it is important to include erect views to prevent misdiagnosis of celiac artery stenosis.

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: (a) All internal carotid artery (ICA) examinations should be performed with gray-scale, color Doppler, and spectral Doppler US. (b) The degree of stenosis determined at gray-scale and Doppler US should be stratified into the categories of normal (no stenosis),50% stenosis, 50%-69% stenosis,or =70% stenosis to near occlusion, near occlusion, and total occlusion. (c) ICA peak systolic velocity (PSV) and presence of plaque on gray-scale and/or color Doppler images are primarily used in diagnosis and grading of ICA stenosis; two additional parameters, 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. (d) ICA should be diagnosed as (i) normal when ICA PSV is less than 125 cm/sec and no plaque or intimal thickening is visible; (ii)50% stenosis when ICA PSV is less than 125 cm/sec and plaque or intimal thickening is visible; (iii) 50%-69% stenosis when ICA PSV is 125-230 cm/sec and plaque is visible; (iv)or =70% stenosis to near occlusion when ICA PSV is greater than 230 cm/sec and visible plaque and lumen narrowing are seen; (v) near occlusion when there is a markedly narrowed lumen at color Doppler US; and (vi) total occlusion when there is no detectable patent lumen at gray-scale US and no flow at spectral, power, and color Doppler US. (e) The final report should discuss velocity measurements and gray-scale 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 the above 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.

Significant hepatic artery stenosis (HAS) after orthotopic liver transplantation (OLT) can lead to thrombosis, with subsequent liver failure in 30% of patients. Although operative intervention or retransplantation has been the traditional solution, endovascular therapy has emerged as a less invasive treatment strategy. Prior smaller studies have been conflicting in the relative efficacy of percutaneous transluminal angioplasty (PTA) vs primary stent placement for HAS.This was a single-center retrospective review of all endovascular interventions for HAS after OLT during a 54-month period (August 2009-December 2013). Patients with ultrasound imaging with evidence of severe HAS (peak systolic velocity400-450 cm/s, resistive index0.5) underwent endovascular treatment with primary stent placement or PTA. Outcomes calculated were technical success, primary and primary assisted patency rates, reinterventions, and complications.Sixty-two interventions for HAS were performed in 42 patients with a mean follow-up of 19.1 ± 15.2 months. During the study period, 654 OLTs were performed. Of 61 patients diagnosed with HAS, 42 underwent an endovascular intervention. The rate of endovascularly treated HAS was 6.4% (42 of 654). Primary technical success was achieved in 95% (59 of 62) of the interventions. Initial treatment was with PTA alone in 17 or primary stent in 25. Primary patency rates after initial stent placement were 87%, 76.5%, 78%, and 78% at 1, 6, 12, and 24 months, respectively, compared with initial PTA rates of 64.7%, 53.3%, 40%, and 0% (P = .19). There were 20 reinterventions in 14 patients (eight stents, six PTAs). The time to the initial reintervention was 51 days in patients with PTA alone vs 105.8 days for those with an initial stent (P = .16). Overall primary assisted patency was 93% at 24 months. Major complications were one arterial rupture and two hepatic artery dissections. The long-term risk of hepatic artery thrombosis in the entire patient cohort was 3.2%.HAS after OLT can be treated endovascularly with high technical success and excellent primary assisted patency. This series represents the largest reported cohort of endovascular interventions for HAS to date. Initial use of a stent showed a strong trend toward decreasing the need for reintervention. Avoidance of hepatic artery thrombosis is possible in95% of patients with endovascular treatment and close follow-up.

Endovascular stenting is a safe, effective treatment of hepatic artery stenosis after liver transplant, but no detailed evaluation has been completed of changes in ultrasound monitoring parameters after stenting. This study aims to improve poststenting surveillance by delineating the expected postoperative findings.Thirty-one stent procedures were performed at our institution for hepatic artery stenosis after liver transplant between October 2010 and October 2012. Of these, 28 (90%) were technically successful, of which 23 met the minimum follow-up time (76 days, defined by the earliest diagnosed restenosis). These patients were followed with serial ultrasound, per the following schedule: within 1 week of stenting, 3 months after stenting, 6 months after stenting, and every 6 months thereafter; additional, unscheduled examinations were frequently performed when indicated on the basis of deterioration of clinical and laboratory status. Follow-up examinations (mean, 268 days total follow-up) were compared with prestenting examinations to evaluate changes in peak systolic velocity (PSV), resistive index (RI), and tardus-parvus waveforms. Data were analyzed to determine a normal range for postprocedure values and time course of change in values.Of the 23 patients, six experienced restenosis. In all patients, mean PSV decreased by 124 cm/s, and mean RI increased by 0.13 within 48 hours after stenting. PSV differed between patency and restenosis groups only at more than 90 days after stenting (mean PSV, 234 and 400 cm/s, respectively), with PSV above 300 cm/s serving as a high-sensitivity threshold for the determination of restenosis. Prestenting RI of below 0.40 had a strong correlation with restenosis. Poststenting RI differed between patency and restenosis groups only at more than 48 hours after stenting, with RI of below 0.55 having a strong correlation with restenosis. Tardus-parvus waveform resolution was often delayed well beyond 48 hours after stenting, and time to tardus-parvus waveform resolution had no correlation with patency or restenosis.Ultrasound is convenient and useful to follow stents in hepatic artery stenosis after liver transplant. Prestenting hemodynamics can have value in predicting restenosis. Diagnosis of restenosis can be made with RI and PSV, whereas resolution time of tardus-parvus waveform is of less concern. These parameters can guide which patients require closer monitoring and aggressive treatment.

Editor: I read with considerable interest the article by Dr Claudon and colleagues in the January 2001 edition of Radiology (1). Dr Claudon and colleagues tested the technical settings of power Doppler ultrasonography (US) to evaluate stenoses by using a phantom. The authors concluded that power Doppler US cannot be used to measure stenoses accurately. I, too, have considerable interest in power Doppler imaging as a method to evaluate flow-limiting stenoses (2). I agree that power Doppler imaging is not the preferred method to measure a stenosis. In our recent article (2), we suggested that power Doppler imaging be used as a screening test, but not as a definitive test. Interestingly, we found that we were more accurate in identifying flow-limiting stenosis at the 60% level, or greater if we used parameters of power Doppler imaging to identify stenosis greater than 40%. Our empirical findings support the present article findings that power Doppler imaging, if used alone, may lead to underestimation of stenosis. However, the authors suggested that “optimal settings (which should be used) were a gain of 30%, pulse repetition frequency below 1,500 Hz, and a low filter level.” We used these parameters to scan some healthy individuals and found that we were unable to detect any flow in the common carotid artery. The parameters that we used to obtain adequate power Doppler information were a gain of approximately 70%, pulse repetition frequency of at least 1,500 Hz, and filter setting of medium to high (Figure). It is important to appreciate that there evidently is a considerable difference in optimal parameters in vitro and in vivo.

To evaluate power Doppler imaging as a possible screening examination for carotid artery stenosis.In the principal pilot study, a prospective, blinded comparison of power Doppler imaging with duplex Doppler imaging, the reference-standard method, was conducted in 100 consecutive patients routinely referred for carotid artery imaging at a large, private multispecialty clinic. In the validation pilot study, a prospective, blinded comparison of power Doppler imaging with digital subtraction angiography, the reference-standard method, was conducted in 20 consecutive patients routinely referred at a teaching hospital. Using conservative assumptions, the authors performed cost-effectiveness analysis.Power Doppler imaging produced diagnostic-quality images in 89% of patients. When the images of the patients with nondiagnostic examinations were regarded as positive, power Doppler imaging had an area under the receiver operating characteristic curve, A(z), of 0.87, sensitivity of 70%, and specificity of 91%. The validation study results were very similar. The cost-effectiveness of screening and, as indicated, duplex Doppler imaging as the definitive diagnostic examination and endarterectomy was $47,000 per quality-adjusted life-year.The A(z) value for power Doppler imaging compares well with that for mammography, a generally accepted screening examination, and with most other imaging examinations. Power Doppler imaging is likely to be a reasonably accurate and cost-effective screening examination for carotid artery stenosis in asymptomatic populations.

In a continuing investigation into the mechanical factors that lead to rupture of abdominal aortic aneurysms, wall pressure and shear stress measurements are presented for steady flow through the series of aneurysm models described in Part I. These models simulate in vivo aortic aneurysms of diameters from 3.3 to 7.5 cm ; the flow rates through the models were dynamically matched to aortic flows under conditions ranging from rest to exercise. For all models, at all flow rates, a pressure maximum was found at the midpoint of the model bulge. This maximum increased with bulge diameter, suggesting that the largest aneurysms in vivo are exposed to the greatest pressures. When the flow was turbulent, the mean wall shear stress at the proximal end of the model bulge had magnitude 2 to 4 dynes/cm 2 , approximately equal to its value in an undilated tube. However, at the distal end of the model bulge the mean shear stress increased to 5 to 10 dynes/cm 2 , whereas the peak instantaneous shear stress exceeded the mean by an order of magnitude. When extrapolated to in vivo parameters, the maximum distal wall shear stress reached levels near those capable of disrupting endothelium. This suggests that turbulence in in vivo aneurysms may precipitate thrombus formation. Subsequent decreased luminal diameters in the presence of thrombus would then lessen the likelihood of turbulent flow and reduce the strength of any turbulence that did occur. It would also reduce the pressure in the aneurysmal bulge. Thus, the presence of turbulent flow may significantly affect risk of rupture.

As an investigation into the mechanical factors that lead to rupture of abdominal aortic aneurysms, both color Doppler flow imaging and laser Doppler velocimetry measurements of steady flow through a series of aneurysm models are presented. The flow pattern in each model consisted of a core of relatively fast-moving fluid traveling through the center of the dilation, surrounded by an outer annulus of slowly recirculating fluid. At flow rates below a Reynolds number of 1750 +/- 150, the flow was smooth, steady, and laminar. At higher flow rates (Reynolds number above 2250 +/- 250), the flow was always irregular and turbulent. Between these fully laminar and fully turbulent regimes the flow was intermittently turbulent. Larger models showed a tendency to become turbulent at lower Reynolds numbers than smaller models. In addition, turbulence was amplified in the distal half of the model dilation, with the largest models producing velocity fluctuations as great as 35% of the time-average centerline velocities. These data suggest that larger aneurysms in vivo may be subject to more frequent and intense turbulence than smaller aneurysms. Concomitantly, increased turbulence may contribute significantly to risk of rupture, as is discussed in Part II.

Ultrasound is a very accurate and cost-effective method for evaluating the aorta and identifying abdominal aortic aneurysms. It is also valuable for following aneurysms for expansion. In the future, the use of color flow Doppler imaging may further prevent the risk of rupture by identifying specific high risk flow patterns. (ECHOCARDIOGRAPHY, Volume 13, March 1996)

OBJECTIVE. The hepatorenal index has been reported to be a sensitive and noninvasive test to quantify steatosis, but it is cumbersome and time-consuming and requires specialized software. The aim of this study was to improve and simplify the hepatorenal index calculation and determine whether it is an effective tool for differentiating patients with steatosis from those without steatosis, thereby eliminating the need for biopsy in a large number of patients. MATERIALS AND METHODS. One hundred one patients who had undergone ultrasound-guided percutaneous liver biopsy at our institution were selected from a patient database. Patients with renal disease, patients with liver masses, and patients whose liver and right kidney were not included on the same image were excluded. Images were acquired with high-resolution ultrasound, and the hepatorenal index was calculated using freeware based on comparison of hepatic and renal brightness. RESULTS. Of the 101 patients, 63 had 5% or less steatosis and 38 had more than 5% steatosis. Using freeware available online from the National Institutes of Health, we calculated hepatorenal index values for all patients. Our data showed a strong correlation between the hepatorenal index and percentage of fat (r = 0.71, p < 0.0001). A hepatorenal index of 1.28 or greater had a 100% sensitivity for identifying more than 5% fat, 54% specificity, 0.57 positive predictive value, and 1.0 negative predictive value. If this method had been used prospectively to select patients for biopsy in our sample, 34% of biopsies could have been avoided. CONCLUSION. The hepatorenal index is a simple, reliable, and cost-effective screening tool for identifying patients who should not undergo liver biopsy for evaluation of steatosis.

As part of a general examination of the effects of blood flow patterns on the risk of rupture of abdominal aortic aneurysms, we have investigated steady flow through a series of polyvinyl chloride models of fusiform aneurysms. A series of steady flow rates between 460 ml/min and 2.0 l/min have been delivered through the models, and the resulting flow patterns have been evaluated by color Doppler flow imaging. At low volume flow rates, the pattern of flow through the model is smooth and laminar. At higher flow rates, however, this is replaced by an irregular, fluctuating, and apparently turbulent motion. This finding is consistent with previous clinical observations. Turbulence appears initially at the distal end of the model aneurysm and then spreads proximally to fill the whole model only if the flow rate continues to increase. The onset of irregular, turbulent flow is found to be governed by both the overall flow rate through the model and the model diameter. Critical conditions for the appearance of turbulence are presented and discussed, and the critical value of the Reynolds number for both the initial distal transition and the final full transition is shown to decrease as the size of the model aneurysm increases.

We performed a retrospective study to determine the sensitivity of mammography in detecting breast cancer arising in women with augmented breasts. Of eight women with breast implants in whom breast cancer developed, six had mammograms before biopsy. Only two of the six cancers were identified mammographically (sensitivity = 33%), and one of these two was seen only in retrospect. In both cases, the mammographic findings suggested a benign rather than a malignant process. All eight women had a palpable mass and early disease, and all are clinically disease-free at present. The sensitivity of mammography in detecting palpable cancers in a control group of women without implants was 92% (118 of 128). For tumors of 2 cm or less, the sensitivity was 88% (58 of 66). These results suggest that the sensitivity of mammography in detecting breast cancer is decreased when implants are present. Further investigations are needed to determine the effects of prostheses on mammographic evaluations.

1. Asymptomatic Palpable Adnexal Masses 2. Acute Pelvic Pain 3. Family History of Ovarian Carcinoma 4. Abnormal Premonopausal Vaginal Bleeding: From Menarche to Menopause 5. Vaginal Bleeding - Postmenopausal 6. Tamoxifen 7. The Use of Ultrasound in the Evaluation and Treatment of the Infertile Woman 8. Sonographic Evaluation of First-Trimester Pain and/or Bleeding 9. Second- and Third-Trimester Bleeding 10. Cervical Sonography in Premature Labor 11. Estimating Gestational Age 12. The Sonographic Evaluation of a Pregnancy Whose Size is Greater than Dates 13. Uterine Size less than Dates: A Clinical Dilemma 14. Ruling Out Fetal Anomalies 15. Family History of Congenital Heart Disease 16. The Role of Sonography in the Evaluation of Pregnant Women with High Maternal Serum a-Fetoprotein 17. Triple Marker Screening Test Positive for Down Syndrome 18. Diabetes Mellitus and Pregnancy: The Role of Ultrasound 19. Sonographic Evaluation of Fetus Following Tertogen Exposure 20. Postpartum Hemorrhage 21.The Breat Nodule: Sonographic Characterization Index

These guidelines are an educationaltool designed to assist practitioners inproviding appropriate radiologic carefor patients. They are not inflexiblerules or requirements of practice andare not intended, nor should they beused, to establish a legal standard ofcare. For these reasons and those setforth below, the American College ofRadiology cautions against the use ofthese guidelines in litigation in whichthe clinical decisions of a practitionerare called into question.The ultimate judgment regardingtheproprietyofanyspecificprocedureor course of action must be made bythe physician or medical physicist inlight of all the circumstances pre-sented. Thus, an approach that differsfrom the guidelines, standing alone,does not necessarily imply that the ap-proach was below the standard ofcare. To the contrary, a conscientiouspractitioner may responsibly adopt acourse of action different from that setforth in the guidelines when, in thereasonable judgment of the practitio-ner, such course of action is indicatedby the condition of the patient, limita-tions on available resources, or ad-vances in knowledge or technologysubsequent to publication of theguidelines. However, a practitionerwho employs an approach substan-tially different from these guidelines isadvised to document in the patientrecord information sufficient to ex-plain the approach taken.The practice of medicine involvesnot only the science, but also the art ofdealing with the prevention, diagno-sis, alleviation, and treatment of dis-ease. The variety and complexity ofhuman conditions make it impossibleto always reach the most appropriatediagnosis or to predict with certainty aparticular response to treatment.Therefore, it should be recognizedthat adherence to these guidelines willnot assure an accurate diagnosis or asuccessful outcome. All that should beexpected is that the practitioner willfollow a reasonable course of actionbased on current knowledge, availableresources, and the needs of the patientto deliver effective and safe medicalcare. The sole purpose of these guide-linesistoassistpractitionersinachiev-ing this objective.

Our objective was to quantitatively assess the value of early posttransplantation hepatic artery resistive indexes in predicting vascular and nonvascular complications in adult orthotopic liver transplant (OLT) patients.Between 1999 and 2001, 110 consecutive adults received grafts. Doppler sonographic graft evaluations measured main, right, and left resistive indexes within 24 to 48 hr after surgery (normal resistive index cutoff, 0.6). Clinical, operative, procedural, and radiologic reports were reviewed for vascular and biliary complications. Frequency, Student's t test, logistic, and regression statistical analyses were performed.even patients (6.4%) had vascular complications, including two (1.8%) hepatic artery and two (1.8%) hepatic vein stenoses, one (0.9%) hepatic vein thrombosis, two (1.8%) portal vein thromboses, and one (0.9%) thrombosis and two (1.8%) stenoses of the inferior vena cava (IVC). In 19 patients (17.3%), biliary complications included anastomotic strictures and leaks 1 week to 18 months after transplantation. In 11 patients (10%), sonographically large hematomas required surgical evacuation. In grafts with vascular complications or large hematomas, the mean early posttransplant main, right, and left indexes were significantly lower (or = 0.6) than without these complications (p0.01). In grafts with and without biliary complications, mean early posttransplant main, right, and left indexes did not differ significantly.In adult OLT patients, low early posttransplant hepatic artery resistive indexes were sensitive (100%) and specific (80%) predictors for vascular complications (e.g., hepatic artery, portal vein, hepatic vein, and IVC) but not for biliary complications. All patients with indexes less than 0.6 within 24-48 hr after surgery should be monitored closely for vascular complications.

Purpose. To study the ability and accuracy of sonography to visualize carotid artery stents and assess criteria for carotid artery stent stenosis. Methods. Duplex Doppler sonographic examinations were performed on 143 patients in whom 158 carotid artery stents were placed. Follow-up sonography to evaluate 24 of these stents within 24 h of stent placement was compared with postprocedure angiography. Another 23 stents were evaluated with sonography and with follow-up angiography more than 24 h after the procedure. The remainder of the 111 stents were evaluated exclusively with sonography after stent placement. Sonography was used to evaluate stent visibility, stent-media separation, and degree of stent stenosis. Results. Wallstents were the best-visualized stents and Acculink the worst, but the differences were not statistically significant. Of 4 patients with stent-media separation >3 mm, 2 (50%) developed stenosis (40%–59%) at 6 and 12 months from stent placement. The other 2 stents with stent-media separation had not developed stenosis at 6 months' follow-up. A comparison of angiography and sonography performed on the date of stent placement revealed 19 true-negative sonography studies, 4 false-positive studies, 1 true-positive study, and no false-negative studies. A comparison of follow-up angiograms performed more than 24 h after the procedure with follow-up sonography revealed 17 true-negative studies, 1 false-positive study, 5 true-positive studies, and no false-negative studies. Conclusions. Sonography allows accurate evaluation of stent placement within the vessel and visualization of stent-media distance. Stent-media sep-aration may be an early detection sign for stent stenosis development. Velocity criteria developed for nonstented vessels, when applied to stented vessels, correlate well with angiographic findings. Doppler velocity measurements when compared with visible stent assessment may reduce false-positives. © 2005 Wiley Periodicals, Inc. J Clin Ultrasound33:321–328, 2005

As an investigation into the mechanical factors which contribute to aneurysm growth and rupture, flow field measurements for steady flow are presented for a range of Reynolds numbers. Steady flow through rigid aneurysm models with roughly elliptical geometry is studied. Data is reported for a model of length 4d and diameter 2.5d, where d is the inner diameter of the entrance tube. Flow rates were chosen such that model Reynolds numbers matched in vivo Reynolds numbers for a range of subject activity level from resting to highly active. Laser-Doppler velocimetry (LDV) was used to verify flow patterns visualized with CDFI, and to quantify the flow velocities during laminar, transition and turbulent flow regimes. A well defined core flow was observed for all Reynolds numbers studied. The observed flow as laminar at Re=450 and Re=1300, and a stable recirculation zone occurred outside the core flow. Turbulent flow was observed at Re=2800 and no recirculation was seen in this case. This investigation represents an initial step in a more extensive study of flow fields within abdominal aortic aneurysms, the results of which will have significant implications for clinical decisions concerning the treatment of aortic aneurysms. >

To evaluate the role and usefulness of diagnostic ultrasonography (US) in the assessment of hemodialysis access grafts with an intermediate probability of graft malfunction.One hundred forty-seven complete US examinations were performed in 91 patients. Average volume of flow, peak systolic velocity, and diameter of residual lumen were recorded. Patients were referred by the nephrology department when clinical findings were suggestive, but not obviously, of graft malfunction. Study results were deemed normal if flow volume exceeded 1,300 mL/min without significant visualized stenosis of 50% of the diameter or greater or if flow approached 1,300 mL/min without peak systolic velocity greater than 400 cm/sec.Of the 147 examinations, 49 (33%) had normal results, seven (5%) showed thrombosis at examination, and 91 (62%) had evidence of at least one significant visualized stenosis or diffuse notable degree of thrombus. Three patients with normal results required fistulography within 90 days, one for thrombosis. In the 91 studies with abnormal results, 69 patients underwent fistulography; results in 63 showed agreement, and three showed false-positive results. More central venous stenoses were found at fistulography than at US.US is a useful and reliable first step in managing clinically suspected hemodialysis graft stenosis. One-third of the studies showed no significant stenosis and did not require angiographic evaluation. US should be the initial study in patients suspected of having hemodialysis access dysfunction without exceptional evidence of stenosis.

Abdominal aortic aneurysms occur in as much as 2-3% of the population, and their rupture produces a mortality rate of 78-94% (1), causing 15,000 deaths per year in the U.S. alone. As an investigation into the mechanical factors that lead to aneurysm rupture, flow field measurements are presented for steady flow through a range of aneurysm sizes and Reynolds numbers. Seven rigid symmetric models of aneurysms were constructed with uniform lengths of 4d and diameters that ranged from 1.4 to 3.3d, where d is the inner diameter of the undilated entrance tube. Color Doppler flow imaging was used to visualize the flow fields, while laser Doppler velocimetry was used to quantify the flow field velocities and to determine critical Reynolds numbers for the onset of, and complete transition to, turbulent flow. Estimates of mean and peak wall shear stresses were derived from velocity measurements. Flow in these models varied from fully laminar to fully turbulent over the range of Reynolds numbers corresponding to in vivo flows. There was a large range over which the flow was intermittently turbulent. High wall shear occurred in the models when the flow was turbulent, suggesting that turbulence in in vivo aneurysms may contribute significantly to their risk of rupture.

To the Editor. —Dr Bundens and colleagues 1 report that the possibility of error in interpretation of venous duplex reports that use the term "superficial femoral vein" may result in improper treatment for patients. However, Bundens et al fail to discuss the responsibility that most radiologists who staff vascular laboratories feel regarding contacting referring physicians when significant abnormalities are detected on venous ultrasound. It is common practice to contact the referring physician and describe the significance of the acute venous thrombosis process when it is noted. As a result, it would be rather unusual for the referring physician to be unaware of the significance of an acute thrombosis involving the superficial femoral vein. While I have no objection to using a new name for this vein to avoid confusion, I do not think changing the name of the vein changes the responsibility of those physicians interpreting this examination to make

A retrospective study of 152 ileostomates with inflammatory bowel disease (IBD) revealed that 16 patients (10.5 per cent) had diagnoses of cholelithiasis before, at the time of, or after having ileostomies. Of the remaining patients, 69 were followed for possible cholelithiasis, most of those with sonographic examination. Sixteen of this latter group of patients (23.2 per cent) were found to have cholelithiasis, usually in an asymptomatic stage. Among women over 50 years old, seven of 11 (63.6 per cent) had gallstones. Due to this high prevalence of cholelithiasis, gallbladder imaging is recommended as a part of the preoperative workup and follow-up of ileostomates. Prophylactic cholecystectomy may be carefully considered in female patients with IBD at the time of proctocolectomy.