Percutaneous Core Biopsy Devices: A Detailed Review and Comparison of Different Needle Designs.

ABSTRACT: Percutaneous core-needle biopsy (PCNB) plays a growing and essential role in many medical specialties. Proper and effective use of various PCNB devices requires basic understanding of how they function. Current literature lacks a detailed overview and illustration of needle function and design differences, a potentially valuable reference for users ranging from early trainees to experts who are less familiar with certain devices. This pictorial aims to provide such an overview, using diagrams and magnified photographs to illustrate the intricate components of these devices. Following a brief historical review of biopsy needle technology for context, we emphasize distinctions in design between 2 major classes of PCNB devices (side- and end-cutting devices), focusing on practical implications for how each device is most effectively used. We believe a nuanced understanding of biopsy device function sheds light on certain lingering ambiguities in biopsy practice, such as the optimal needle gauge in organ biopsy, the benefits and risks associated with coaxial technique, the impact of needle selection and technique on bleeding, and the risk of unsuccessful sampling. In a subsequent pictorial, we will draw on the concepts presented here to illustrate examples of biopsy needle failure and how unrecognized needle failure can be an important and often preventable cause of increased biopsy risk and lower tissue yield.

Imaging AI in Practice: A Demonstration of Future Workflow Using Integration Standards.

Artificial intelligence (AI) tools are rapidly being developed for radiology and other clinical areas. These tools have the potential to dramatically change clinical practice; however, for these tools to be usable and function as intended, they must be integrated into existing radiology systems. In a collaborative effort between the Radiological Society of North America, radiologists, and imaging-focused vendors, the Imaging AI in Practice (IAIP) demonstrations were developed to show how AI tools can generate, consume, and present results throughout the radiology workflow in a simulated clinical environment. The IAIP demonstrations highlight the critical importance of semantic and interoperability standards, as well as orchestration profiles for successful clinical integration of radiology AI tools. Keywords: Computer Applications-General (Informatics), Technology Assessment © RSNA, 2021.

CT Esophagography for Evaluation of Esophageal Perforation.

Esophageal emergencies such as rupture or postoperative leak are uncommon but may be life threatening when they occur. Delay in their diagnosis and treatment may significantly increase morbidity and mortality. Causes of esophageal injury include iatrogenic (including esophagogastroduodenoscopy and stent placement), foreign body ingestion, blunt or penetrating trauma to the chest or abdomen, and forceful retching, also called Boerhaave syndrome. Although fluoroscopic esophagography remains the imaging study of choice according the American College of Radiology appropriateness criteria, CT esophagography has been shown to be at least equal to if not superior to fluoroscopic evaluation for esophageal injury. In addition, CT esophagography allows diagnosis of extraesophageal abnormalities, both as the cause of the patient's symptoms as well as incidental findings. CT esophagography also allows rapid diagnosis since the examination can be readily performed in most clinical settings and requires no direct radiologist supervision, requiring only properly trained technologists and a CT scanner. Multiple prior studies have shown the limited utility of fluoroscopic esophagography after a negative chest CT scan and the increase in accuracy after adding oral contrast agent to CT examinations, although there is considerable variability of CT esophagography protocols among institutions. Development of a CT esophagography program, utilizing a well-defined protocol with input from staff from the radiology, gastroenterology, emergency, and general surgery departments, can facilitate more rapid diagnosis and patient care, especially in overnight and emergency settings. The purpose of this article is to familiarize radiologists with CT esophagography techniques and imaging findings of emergent esophageal conditions. Online supplemental material is available for this article. ©RSNA, 2021.

Atherosclerotic Plaque Burden on Abdominal CT: Automated Assessment With Deep Learning on Noncontrast and Contrast-enhanced Scans.

BACKGROUND: Abdominal aortic atherosclerotic plaque burden may have clinical significance but manual measurement is time-consuming and impractical. PURPOSE: To perform external validation on an automated atherosclerotic plaque detector for noncontrast and postcontrast abdominal CT. MATERIALS AND METHODS: The training data consisted of 114 noncontrast CT scans and 23 postcontrast CT urography scans. The testing data set consisted of 922 CT colonography (CTC) scans, and 1207 paired noncontrast and postcontrast CT scans from renal donors from a second institution. Reference standard data included manual plaque segmentations in the 137 training scans and manual plaque burden measurements in the 922 CTC scans. The total Agatston score and group (0-3) was determined using fully-automated deep learning software. Performance was assessed by measures of agreement, linear regression, and paired evaluations. RESULTS: On CTC scans, automated Agatston scoring correlated highly with manual assessment (R2 = 0.94). On paired renal donor CT scans, automated Agatston scoring on postcontrast CT correlated highly with noncontrast CT (R2 = 0.95). When plaque burden was expressed as a group score, there was excellent agreement for both the CTC (weighted kappa 0.80 ± 0.01 [95% confidence interval: 0.78-0.83]) and renal donor (0.83 ± 0.02 [0.79-0.86]) assessments. CONCLUSION: Fully automated detection, segmentation, and scoring of abdominal aortic atherosclerotic plaques on both pre- and post-contrast CT was validated and may have application for population-based studies.

Structured Reporting in Ultrasound.

Structured reporting of ultrasound examinations can add value throughout the imaging chain. Reports may be created in a more efficient manner, with increased accuracy and clarity. Communication with referring providers and patients may be improved. Patient care can be enhanced through improved adherence with guidelines and local best practices. Radiology departments may benefit from improved billing and quality reporting. Consistent discrete data can enable research and collaborations between institutions. This article will review the multifaceted impact of structuring ultrasound reports.

CT automated exposure control using a generalized detectability index.

PURPOSE: Identifying an appropriate tube current setting can be challenging when using iterative reconstruction due to the varying relationship between spatial resolution, contrast, noise, and dose across different algorithms. This study developed and investigated the application of a generalized detectability index ( d gen ' ) to determine the noise parameter to input to existing automated exposure control (AEC) systems to provide consistent image quality (IQ) across different reconstruction approaches. METHODS: This study proposes a task-based automated exposure control (AEC) method using a generalized detectability index ( d gen ' ). The proposed method leverages existing AEC methods that are based on a prescribed noise level. The generalized d gen ' metric is calculated using lookup tables of task-based modulation transfer function (MTF) and noise power spectrum (NPS). To generate the lookup tables, the American College of Radiology CT accreditation phantom was scanned on a multidetector CT scanner (Revolution CT, GE Healthcare) at 120 kV and tube current varied manually from 20 to 240 mAs. Images were reconstructed using a reference reconstruction algorithm and four levels of an in-house iterative reconstruction algorithm with different regularization strengths (IR1-IR4). The task-based MTF and NPS were estimated from the measured images to create lookup tables of scaling factors that convert between d gen ' and noise standard deviation. The performance of the proposed d gen ' -AEC method in providing a desired IQ level over a range of iterative reconstruction algorithms was evaluated using the American College of Radiology (ACR) phantom with elliptical shell and using a human reader evaluation on anthropomorphic phantom images. RESULTS: The study of the ACR phantom with elliptical shell demonstrated reasonable agreement between the d gen ' predicted by the lookup table and d ' measured in the images, with a mean absolute error of 15% across all dose levels and maximum error of 45% at the lowest dose level with the elliptical shell. For the anthropomorphic phantom study, the mean reader scores for images resulting from the d gen ' -AEC method were 3.3 (reference image), 3.5 (IR1), 3.6 (IR2), 3.5 (IR3), and 2.2 (IR4). When using the d gen ' -AEC method, the observers' IQ scores for the reference reconstruction were statistical equivalent to the scores for IR1, IR2, and IR3 iterative reconstructions (P > 0.35). The d gen ' -AEC method achieved this equivalent IQ at lower dose for the IR scans compared to the reference scans. CONCLUSIONS: A novel AEC method, based on a generalized detectability index, was investigated. The proposed method can be used with some existing AEC systems to derive the tube current profile for iterative reconstruction algorithms. The results provide preliminary evidence that the proposed d gen ' -AEC can produce similar IQ across different iterative reconstruction approaches at different dose levels.

Does Nonenhanced CT-based Quantification of Abdominal Aortic Calcification Outperform the Framingham Risk Score in Predicting Cardiovascular Events in Asymptomatic Adults?

Purpose To determine if abdominal aortic calcification (AAC) at CT predicts cardiovascular events independent of Framingham risk score (FRS). Materials and Methods For this retrospective study, electronic health records for 829 asymptomatic patients (mean age, 57.9 years; 451 women, 378 men) who underwent nonenhanced CT colonography screening between April 2004 and March 2005 were reviewed for subsequent cardiovascular events; mean follow-up interval was 11.2 years ± 2.8 (standard deviation). Institutional review board approval was obtained. CT-based AAC was retrospectively quantified as a modified Agatston score by using a semiautomated tool. Kaplan-Meier curves and Cox proportional hazards models were used for time-to-event analysis; receiver operating characteristic curves and net reclassification improvement compared predictive abilities of AAC and FRS. Results An index cardiovascular event occurred after CT in 156 (19%) of 829 patients (6.7 years ± 3.5, including heart attack in 39 [5%] and death in 79 [10%]). AAC was higher in the cardiovascular event cohort (mean AAC, 3478 vs 664; P < .001). AAC was a strong predictor of cardiovascular events at both univariable and multivariable Cox modeling, independent of FRS (P < .001). Kaplan-Meier plots showed better separation with AAC over FRS. The area under the receiver operating characteristic curve (AUC) was higher for AAC than FRS at all evaluated time points (eg, AUC of 0.82 vs 0.64 at 2 years; P = .014). By using a cutoff point of 200, AAC improved FRS risk categorization with net reclassification improvement of 35.4%. Conclusion CT-based abdominal aortic calcification was a strong predictor of future cardiovascular events, outperforming the Framingham risk score. This finding suggests a potential opportunistic role in abdominal nonenhanced CT scans performed for other clinical indications. © RSNA, 2018.

Semiautomated System for Nonurgent, Clinically Significant Pathology Results.

BACKGROUND: Failure of timely test result follow-up has consequences including delayed diagnosis and treatment, added costs, and potential patient harm. Closed-loop communication is key to ensure clinically significant test results (CSTRs) are acknowledged and acted upon appropriately. A previous implementation of the Alert Notification of Critical Results (ANCR) system to facilitate closed-loop communication of imaging CSTRs yielded improved communication of critical radiology results and enhanced adherence to institutional CSTR policies. OBJECTIVE: This article extends the ANCR application to pathology and evaluates its impact on closed-loop communication of new malignancies, a common and important type of pathology CSTR. MATERIALS AND METHODS: This Institutional Review Board-approved study was performed at a 150-bed community, academically affiliated hospital. ANCR was adapted for pathology CSTRs. Natural language processing was used on 30,774 pathology reports 13 months pre- and 13 months postintervention, identifying 5,595 reports with malignancies. Electronic health records were reviewed for documented acknowledgment for a random sample of reports. Percent of reports with documented acknowledgment within 15 days assessed institutional policy adherence. Time to acknowledgment was compared pre- versus postintervention and postintervention with and without ANCR alerts. Pathologists were surveyed regarding ANCR use and satisfaction. RESULTS: Acknowledgment within 15 days was documented for 98 of 107 (91.6%) pre- and 89 of 103 (86.4%) postintervention reports (p = 0.2294). Median time to acknowledgment was 7 days (interquartile range [IQR], 3, 11) preintervention and 6 days (IQR, 2, 10) postintervention (p = 0.5083). Postintervention, median time to acknowledgment was 2 days (IQR, 1, 6) for reports with ANCR alerts versus 6 days (IQR, 2.75, 9) for reports without alerts (p = 0.0351). ANCR alerts were sent on 15 of 103 (15%) postintervention reports. All pathologists reported that the ANCR system positively impacted their workflow; 75% (three-fourths) felt that the ANCR system improved efficiency of communicating CSTRs. CONCLUSION: ANCR expansion to facilitate closed-loop communication of pathology CSTRs was favorably perceived and associated with significant improved time to documented acknowledgment for new malignancies. The rate of adherence to institutional policy did not improve.

Renal cancer at unenhanced CT: imaging features, detection rates, and outcomes.

PURPOSE: To describe and quantify the rate of detection of renal cancer on unenhanced CT. METHODS: This retrospective, HIPAA-compliant study was approved by the Institutional Review Board. Electronic health records for all patients who underwent unenhanced abdominal CT at our institution between 2000 and 2005 were reviewed to identify patients subsequently diagnosed with renal cancer during a follow-up period of up to 12 years. Images were reviewed to determine if the cancer was visible at index (first) unenhanced CT and their findings recorded. Original radiology reports were reviewed to determine whether the renal cancer was reported; Fisher's Exact Test compared imaging features of detected and missed cancers. Clinical outcomes including time until diagnosis and stage at diagnosis were used to assess the potential impact of missed cancers. RESULTS: Of 15,695 patients, 82 (0.52%) were diagnosed with renal cancer. Of these, 43/82 (52%) cancers were retrospectively detectable on index unenhanced CT. Among retrospectively detectable cancers, 63% (27/43) were originally detected and reported on index CT and 37% (16/43) were missed. Size was the only feature associated with detection; 83% (20/24) of cancers > 3.0 cm were detected versus 37% (7/19) of cancers ≤ 3.0 cm (p = 0.0036). Although none of the 16 missed renal cancers developed metastases between index CT and time of diagnosis (median 33.5 months), 4 (25%) progressed in stage. CONCLUSIONS: Renal cancer was rare in patients undergoing unenhanced abdominal CT. Over one-third of potentially detectable cancers were missed prospectively. However, missed cancers did not metastasize and infrequently progressed in stage before being diagnosed.

Characterizing indeterminate liver lesions in patients with localized pancreatic cancer at the time of diagnosis.

BACKGROUND: In patients with newly diagnosed pancreatic cancer, the classification of indeterminate liver lesions is an unanswered clinical dilemma as misclassification of these lesions can impact the assignment of clinical stage and subsequent treatment planning. Our objective was to design a standardized classification system to more accurately define the risk of malignancy in indeterminate liver lesions. METHODS: In this retrospective study, patients with localized, non-metastatic pancreatic cancer were identified and pre-treatment computed tomography (CT) scans were evaluated for the presence or absence of liver lesions. Liver lesions were defined as definitely benign (1) or indeterminate (2). Indeterminate lesions were further sub-classified as either indeterminate probably benign (2B) or indeterminate possibly malignant (2M). The index liver lesion was evaluated on follow-up imaging for stability or unequivocal disease progression. RESULTS: From 2008 to 2015, 304 patients with localized, non-metastatic pancreatic cancer were identified and 125 (41%) patients had liver lesions. Of the 125 patients, the liver lesions in 35 (28%) were classified as definitely benign and in 90 (72%) patients they were classified as indeterminate. The 90 patients with indeterminate lesions included 80 (89%) classified as indeterminate probably benign (2B) and 10 (11%) classified as indeterminate possibly malignant (2M). After a median follow-up of 56 weeks, no patient with a definitely benign lesion had metastatic disease progression of the index lesion. Of the 90 patients with indeterminate liver lesions, the index lesion progressed to unequivocal liver metastasis in 8 (9%) patients; 5 (6%) of the 80 lesions classified as indeterminate probably benign (2B), and 3 (30%) of the ten lesions classified as indeterminate possibly malignant (2M). The sensitivity of the classification system was 38% and the specificity was 91%. The positive predictive value was 30% and the negative predictive value was 94%. CONCLUSIONS: A significant proportion of patients with localized pancreatic cancer will have liver lesions identified at the time of diagnosis and most of these lesions will have indeterminate characteristics. A classification system which further stratifies indeterminate liver lesions by malignant potential can assist clinicians in determining optimal treatment plan and is associated with a high negative predictive value.

Impact of an electronic alert notification system embedded in radiologists' workflow on closed-loop communication of critical results: a time series analysis.

INTRODUCTION: Optimal critical test result communication is a Joint Commission national patient safety goal and requires documentation of closed-loop communication among care providers in the medical record. Electronic alert notification systems can facilitate an auditable process for creating alerts for transmission and acknowledgement of critical test results. We evaluated the impact of a patient safety initiative with an alert notification system on reducing critical results lacking documented communication, and assessed potential overuse of the alerting system for communicating results. METHODS: We implemented an alert notification system-Alert Notification of Critical Results (ANCR)-in January 2010. We reviewed radiology reports finalised in 2009-2014 which lacked documented communication between the radiologist and another care provider, and assessed the impact of ANCR on the proportion of such reports with critical findings, using trend analysis over 10 semiannual time periods. To evaluate potential overuse of ANCR, we assessed the proportion of reports with non-critical results among provider-communicated reports. RESULTS: The proportion of reports with critical results among reports without documented communication decreased significantly over 4 years (2009-2014) from 0.19 to 0.05 (p<0.0001, Cochran-Armitage trend test). The proportion of provider-communicated reports with non-critical results remained unchanged over time before and after ANCR implementation (0.20 to 0.15, p=0.45, Cochran-Armitage trend test). CONCLUSIONS: A patient safety initiative with an alert notification system reduced the proportion of critical results among reports lacking documented communication between care providers. We observed no change in documented communication of non-critical results, suggesting the system did not promote overuse. Future studies are needed to evaluate whether such systems prevent subsequent patient harm.

Does integrating nonurgent, clinically significant radiology alerts within the electronic health record impact closed-loop communication and follow-up?

OBJECTIVE: To assess whether integrating critical result management software--Alert Notification of Critical Results (ANCR)--with an electronic health record (EHR)-based results management application impacts closed-loop communication and follow-up of nonurgent, clinically significant radiology results by primary care providers (PCPs). MATERIALS AND METHODS: This institutional review board-approved study was conducted at a large academic medical center. Postintervention, PCPs could acknowledge nonurgent, clinically significant ANCR-generated alerts ("alerts") within ANCR or the EHR. Primary outcome was the proportion of alerts acknowledged via EHR over a 24-month postintervention. Chart abstractions for a random sample of alerts 12 months preintervention and 24 months postintervention were reviewed, and the follow-up rate of actionable alerts (eg, performing follow-up imaging, administering antibiotics) was estimated. Pre- and postintervention rates were compared using the Fisher exact test. Postintervention follow-up rate was compared for EHR-acknowledged alerts vs ANCR. RESULTS: Five thousand nine hundred and thirty-one alerts were acknowledged by 171 PCPs, with 100% acknowledgement (consistent with expected ANCR functionality). PCPs acknowledged 16% (688 of 4428) of postintervention alerts in the EHR, with the remaining in ANCR. Follow-up was documented for 85 of 90 (94%; 95% CI, 88%-98%) preintervention and 79 of 84 (94%; 95% CI, 87%-97%) postintervention alerts (P > .99). Postintervention, 11 of 14 (79%; 95% CI, 52%-92%) alerts were acknowledged via EHR and 68 of 70 (97%; 95% CI, 90%-99%) in ANCR had follow-up (P = .03). CONCLUSIONS: Integrating ANCR and EHR provides an additional workflow for acknowledging nonurgent, clinically significant results without significant change in rates of closed-loop communication or follow-up of alerts.

Four-year impact of an alert notification system on closed-loop communication of critical test results.

OBJECTIVE: One of the patient safety goals proposed by the Joint Commission urges hospitals to develop a policy for communicating critical test results and to measure adherence to that policy. We evaluated the impact of an alert notification system on policy adherence for communicating critical imaging test results to referring providers and assessed system adoption over the first 4 years after implementation. MATERIALS AND METHODS: This study was performed in a 753-bed academic medical center. The intervention, an automated alert notification system for critical results, was implemented in January 2010. The primary outcome was adherence to institutional policy for timely closed-loop communication of critical imaging results, and the secondary outcome was system adoption. Policy adherence was determined through manual review of a random sample of radiology reports from the first 4 years after the intervention (n = 37,604) compared with baseline outcomes 1 year before the intervention (n = 9430). Adoption was evaluated by quantifying the use of the system overall and the proportion of alerts that used noninterruptive communication as a percentage of all reports generated by 320 radiologists (n = 1,538,059). A statistical analysis of the trend at 6-month intervals over 4 years was performed using a chi-square trend test. RESULTS: Adherence to the policy increased from 91.3% before the intervention to 95.0% after the intervention (p < 0.0001). There was a ninefold increase in the critical results communicated via the system (chi-square trend test, p < 0.0001). During the first 4 years after the intervention, 41,445 alerts (41% of the total number of alerts) used the system's noninterruptive process for communicating less urgent critical results, which was substantially unchanged over the 4 years postintervention, thus reducing unnecessary paging interruptions. CONCLUSION: An automated alert notification system for communicating critical imaging results was successfully adopted and was associated with increased adherence to institutional policy for communicating critical test results and with reduced workflow interruptions.

Journal club: Requiring clinical justification to override repeat imaging decision support: impact on CT use.

OBJECTIVE: The purpose of this study was to determine the impact of requiring clinical justification to override decision support alerts on repeat use of CT. SUBJECTS AND METHODS: This before and after intervention study was conducted at a 793-bed tertiary hospital with computerized physician order entry and clinical decision support systems. When a CT order is placed, decision support alerts the orderer if the patient's same body part has undergone CT within the past 90 days. The study cohort included all 28,420 CT orders triggering a repeat alert in 2010. The intervention required clinical justification, selected from a predetermined menu, to override repeat CT decision support alerts to place a CT order; otherwise the order could not be placed and was dropped. The primary outcome, dropped repeat CT orders, was analyzed using three methods: chi-square tests to compare proportions dropped before and after intervention; multiple logistic regression tests to control for orderer, care setting, and patient factors; and statistical process control for temporal trends. RESULTS: The repeat CT order drop rate had an absolute increase of 1.4%; 6.1% (682/11,230) before to 7.5% (1290/17,190) after intervention, which was a 23% relative change (7.5 - 6.1)/6.1 × 100 = 23%; p < 0.0001). Orders were dropped more often after intervention (odds ratio, 1.3; 95% CI, 1.1-1.4; p < 0.0001). Statistical control analysis supported the association between the increase in the drop rate with intervention rather than underlying trends. CONCLUSION: Adding a requirement for clinical justification to override alerts modestly but significantly improves the impact of repeat CT decision support (23% relative change), with the overall effect of preventing one in 13 repeat CT orders.

Automated critical test result notification system: architecture, design, and assessment of provider satisfaction.

OBJECTIVE: Communicating critical results of diagnostic imaging procedures is a national patient safety goal. The purposes of this study were to describe the system architecture and design of Alert Notification of Critical Results (ANCR), an automated system designed to facilitate communication of critical imaging results between care providers; to report providers' satisfaction with ANCR; and to compare radiologists' and ordering providers' attitudes toward ANCR. MATERIALS AND METHODS: The design decisions made for each step in the alert communication process, which includes user authentication, alert creation, alert communication, alert acknowledgment and management, alert reminder and escalation, and alert documentation, are described. To assess attitudes toward ANCR, internally developed and validated surveys were administered to all radiologists (n = 320) and ordering providers (n = 4323) who sent or received alerts 3 years after ANCR implementation. RESULTS: The survey response rates were 50.4% for radiologists and 36.1% for ordering providers. Ordering providers were generally dissatisfied with the training received for use of ANCR and with access to technical support. Radiologists were more satisfied with documenting critical result communication (61.1% vs 43.2%; p = 0.0001) and tracking critical results (51.6% vs 35.1%; p = 0.0003) than were ordering providers. Both groups agreed use of ANCR reduces medical errors and improves the quality of patient care. CONCLUSION: Use of ANCR enables automated communication of critical test results. The survey results confirm overall provider satisfaction with ANCR but highlight the need for improved training strategies for large numbers of geographically dispersed ordering providers. Future enhancements beyond acknowledging receipt of critical results are needed to help ensure timely and appropriate follow-up of critical results to improve quality and patient safety.

Simple cyst-appearing renal masses at unenhanced CT: can they be presumed to be benign?

PURPOSE: To determine renal cancer incidence in simple cyst-appearing renal masses detected at unenhanced computed tomography (CT). MATERIALS AND METHODS: Institutional review board approval and an informed consent waiver for this retrospective HIPAA-compliant study were obtained. Patients who had renal masses with homogeneous water attenuation, hairline-thin smooth walls, and no calcifications or septations were identified by applying a validated natural language processing algorithm to radiology reports for 15 695 unique patients who underwent unenhanced abdominal CT at our institution between 2000 and 2005. Reports that included renal masses were selected, then categorized through manual report review as pertaining to simple cyst-appearing renal masses, nonsimple or solid renal masses, or no renal masses. Medical records were reviewed for subsequent renal cancer diagnoses. Patients without renal cancer were evaluated for a minimum of 5 years (mean, 8 years; range, 5-12 years). The Cox proportional hazards regression model was used to compare renal cancer incidence for patients who had simple cyst-appearing renal masses with those who had nonsimple cystic or solid renal masses and those who had no renal masses. RESULTS: Simple cyst-appearing renal masses were identified in 2669 patients (17%), no renal masses in 11844 (75%), and nonsimple cystic or solid renal masses in 1182 (8%). Of 1159 patients with simple cyst-appearing renal masses and a minimum of 5 years of follow-up, six (0.52%) subsequently developed renal cancers, all of which were separate from the simple cyst-appearing renal mass, rather than within it. Of 446 patients with nonsimple or solid renal masses and sufficient follow-up, 50 (11%) developed renal cancer. There was no difference in renal cancer incidence in patients with simple cyst-appearing renal masses versus those without renal masses (P = .54). The incidence of renal cancer was significantly lower in patients with simple cyst-appearing renal masses than that in nonsimple cystic or solid renal masses (P < .0001). CONCLUSION: Simple cyst-appearing renal masses are unlikely to be malignant. These data support foregoing further imaging evaluation of these common masses.

Visceral adiposity and hepatic steatosis at abdominal CT: association with the metabolic syndrome.

OBJECTIVE: Visceral adiposity and hepatic steatosis may correlate with the metabolic syndrome but are not currently among the diagnostic criteria. We evaluated these features at unenhanced MDCT. MATERIALS AND METHODS: Semiautomated measurements of subcutaneous fat area, visceral fat area, and visceral fat percentage were obtained at the umbilical level at unenhanced MDCT of 474 adults (217 men, 257 women; mean age, 58.3 years) using a dedicated application (Fat Assessment Tool, EBW version 4.5). Unenhanced liver attenuation was also recorded. Metabolic syndrome was defined using the criteria proposed by the International Diabetes Federation in 2005. RESULTS: The prevalence of metabolic syndrome was 35.0% (76/217) among men and 35.8% (92/257) among women. The area under the receiver operating characteristic curve (AUC) for visceral fat area was 0.830 (95% CI, 0.784-0.867) in men and 0.887 (0.848-0.918) in women (p = 0.162). The AUC for subcutaneous fat area was 0.865 (0.823-0.899) in men and 0.762 (0.711-0.806) in women (p = 0.024). The AUC for visceral fat percentage was 0.527 (0.472-0.581) in men and 0.820 (0.774-0.859) in women (p < 0.001). The AUC for liver attenuation was 0.706 (0.653-0.754). Thresholds of subcutaneous fat area greater than 204 cm(2) in men, visceral fat area greater than 70 cm(2) in women, and liver attenuation less than 50 HU yielded a sensitivity and specificity of 80.3% and 83.7%; 83.7% and 80.0%; and 22.0% and 96.7%, respectively. Visceral fat area was elevated in 55% of patients without metabolic syndrome (11/20) but with a documented cardiovascular event or complication and in 32.1% of patients with a body mass index of 30 kg/m(2) or less. CONCLUSION: Accumulation of visceral fat was the best predictor for metabolic syndrome in women. Unexpectedly, the percentage of visceral fat was a poor predictor for metabolic syndrome in men and subcutaneous fat area was best. Decreased liver attenuation was insensitive but was highly specific for metabolic syndrome. The implications of these sex-specific differences and the relationship of fat-based CT measures to cardiovascular risk warrant further investigation.