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Background: Preprocedural 3-dimensional CT imaging of the aortic annular plane plays a critical role for transcatheter aortic valve replacement (TAVR) planning; however, manual reconstructions are complex. Automated analysis software may improve reproducibility and agreement between readers but is incompletely validated., Methods: In 110 TAVR patients (mean age, 81 years; 37% female) undergoing preprocedural multidetector CT, automated reconstruction of the aortic annular plane and planimetry of the annulus was performed with a prototype of now commercially available software (syngo.CT Cardiac Function-Valve Pilot; Siemens Healthcare, Erlangen, Germany). Fully automated, semiautomated, and manual annulus measurements were compared. Intrareader and inter-reader agreement, intermodality agreement, and interchangeability were analyzed. Finally, the impact of these measurements on recommended valve size was evaluated., Results: Semiautomated analysis required major correction in 5 patients (4.5%). In the remaining 95.5%, only minor correction was performed. Mean manual annulus area was significantly smaller than fully automated results (P < .001 for both readers) but similar to semiautomated measurements (5.0 vs 5.4 vs 4.9 cm(2), respectively). The frequency of concordant recommendations for valve size increased if manual analysis was replaced with the semiautomated method (60% agreement was improved to 82.4%; 95% confidence interval for the difference [69.1%-83.4%])., Conclusions: Semiautomated aortic annulus analysis, with minor correction by the user, provides reliable results in the context of TAVR annulus evaluation., (Copyright © 2015 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.)

Aim: To compare radiation dose surrogates [volume CT dose index (CTDIvol), dose-length product (DLP), size-specific dose estimate (SSDE), and effective dose] and image noise in a cohort of patients undergoing hepatocellular carcinoma screening who underwent both single-energy CT (SECT) and dual-energy CT (DECT)., Materials and Methods: In this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study, 74 adults (mean age 59.5 years) underwent 64 section SECT (120 kVp and weight-based reference mAs) and 128 section dual-source DECT (100/Sn 140 kVp and CTDIvol, adjusted to match the CDTIvol of the SECT protocol) on different occasions. Noise levels were measured in the liver, inferior vena cava (IVC), retroperitoneal (RP) fat, and aorta. Generalized linear models were constructed to compare dose and noise, adjusting for effective diameter., Results: The total DLP (1371.11 mGy-cm, SD = 527.91) and effective dose (20.57 mSv, SD = 7.92) with SECT were significantly higher than the DLP (864.84 mGy-cm, SD = 322.10) and effective dose (12.97 mSv, SD = 4.83) with DECT (p < 0.001). The differences between SECT and DECT increased as the patient's effective diameter increased (p < 0.001). Noise levels in the liver (22.4 versus 21.9 HU), IVC (22.3 versus 23.4 HU), and RP fat (23.5 versus 23 HU) were similar for DECT and SECT (p > 0.05) but were significantly lower in the aorta for DECT (25.3 versus 26.4 HU; p = 0.006)., Conclusion: DECT imaging of the abdomen can achieve noise levels comparable to those seen with SECT imaging without a dose penalty to patients., (Copyright © 2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Objectives: To assess the value of secretin during magnetic resonance cholangiopancreatography (MRCP) in demonstrating communication between cystic lesions and the pancreatic duct to help determine the diagnosis of side-branch intraductal papillary mucinous neoplasm (SB-IPMN)., Methods: This is an IRB-approved, HIPAA-compliant retrospective study of 29 SB-IPMN patients and 13 non-IPMN subjects (control) who underwent secretin-enhanced MRCP (s-MRCP). Two readers blinded to the final diagnosis reviewed three randomised image sets: (1) pre-secretin HASTE, (2) dynamic s-MRCP and (3) post-secretin HASTE. Logistic regression, generalised linear models and ROC analyses were used to compare pre- and post-secretin results., Results: There was no significant difference in median scores for the pre-secretin [reader 1: 1; reader 2: 2 (range -2 to 2)] and post-secretin HASTE [reader 1: 1; reader 2: 1 (range -2 to 2)] in the SB-IPMN group (P = 0.14), while the scores were lower for s-MRCP [reader 1: 0.5 (range -2 to 2); reader 2: 0 (range -1 to 2); P = 0.016]. There was no significant difference in mean maximum diameter of SB-IPMN on pre- and post-secretin HASTE, and s-MRCP (P > 0.05)., Conclusion: Secretin stimulation did not add to MRCP in characterising pancreatic cystic lesions as SB-IPMN., Key Points: Magnetic resonance cholangiopancreatography (MRCP) is used to evaluate pancreatic cystic lesions. Intraductal papillary mucinous neoplasm (IPMN) is a type of pancreatic cystic neoplasm. Secretin administration does not facilitate the diagnosis of IPMN on MRCP.

Objective: Iterative metal artifact reduction (IMAR) is a sinogram inpainting technique that incorporates high-frequency data from standard weighted filtered back projection (WFBP) reconstructions to reduce metal artifact on computed tomography (CT). This study was designed to compare the image quality of IMAR and WFBP in total shoulder arthroplasties (TSA); determine the optimal amount of WFBP high-frequency data needed for IMAR; and compare image quality of the standard 3D technique with that of a faster 2D technique., Materials and Methods: Eight patients with nine TSA underwent CT with standardized parameters: 140 kVp, 300 mAs, 0.6 mm collimation and slice thickness, and B30 kernel. WFBP, three 3D IMAR algorithms with different amounts of WFBP high-frequency data (IMARlo, lowest; IMARmod, moderate; IMARhi, highest), and one 2D IMAR algorithm were reconstructed. Differences in attenuation near hardware and away from hardware were measured and compared using repeated measures ANOVA. Five readers independently graded image quality; scores were compared using Friedman's test., Results: Attenuation differences were smaller with all 3D IMAR techniques than with WFBP (p < 0.0063). With increasing high-frequency data, the attenuation difference increased slightly (differences not statistically significant). All readers ranked IMARmod and IMARhi more favorably than WFBP (p < 0.05), with IMARmod ranked highest for most structures. The attenuation difference was slightly higher with 2D than with 3D IMAR, with no significant reader preference for 3D over 2D., Conclusions: IMAR significantly decreases metal artifact compared to WFBP both objectively and subjectively in TSA. The incorporation of a moderate amount of WFBP high-frequency data and use of a 2D reconstruction technique optimize image quality and allow for relatively short reconstruction times.

Rationale and Objectives: New tests are typically assessed by estimating their technical and diagnostic performance through comparisons with a reference standard. A valid reference standard, however, is not always available and is not required for assessing the interchangeability of a new test with an existing one., Materials and Methods: To show interchangeability of a new test with an existing test, one compares the differences in diagnoses between the new and existing tests to differences between diagnoses made with the existing test on several occasions. We illustrate the test for interchangeability with two studies. In a transcatheter aortic valve replacement study, we test whether semiautomated analysis can be used interchangeably with manual reconstructions from three-dimensional computed tomography (CT) images. In patients with femoroacetabular impingement, we test whether magnetic resonance imaging (MRI) can replace CT to measure acetabular version., Results: Although the semiautomated method agreed often with the manual measurement of aortic valve size (87.6%), interchanging the semiautomated method with manual measurements by an expert would lead to a 1.7%-12.2% increase in the frequency of disagreement. Interchanging MRI for CT to measure acetabular version would lead to differences in angle measurements of 2.0° to 3.1° in excess of the differences we would expect to see with CT alone., Conclusions: Testing for agreement or correlation between a new and an existing test is not sufficient evidence of the performance of a new test. A formal evaluation of interchangeability can be conducted in the absence of a reference standard., (Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.)

Background Context: There are often multiple surgical treatment options for a spinal pathology. In addition, there is a lack of data that define differences in surgical treatment among surgeons in the United States., Purpose: To assess the surgical treatment patterns among neurologic and orthopedic spine surgeons in the United States for the treatment of one- and two-time recurrent lumbar disc herniation., Study Design: Electronic survey., Patient Sample: An electronic survey was delivered to 2,560 orthopedic and neurologic surgeons in the United States., Outcome Measures: The response data were analyzed to assess the differences among respondents over various demographic variables. The probability of disagreement is reported for various surgeon subgroups., Methods: A survey of clinical and radiographic case scenarios that included a one- and two-time lumbar disc herniation was electronically delivered to 2,560 orthopedic and neurologic surgeons in the United States. The surgical treatment options were revision microdiscectomy, revision microdiscectomy with in situ fusion, revision microdiscectomy with posterolateral fusion using pedicle screws, revision microdiscectomy with posterior lumbar interbody fusion/transforaminal lumbar interbody fusion (PLIF/TLIF), anterior lumbar interbody fusion (ALIF) with percutaneous screws, ALIF with open posterior instrumentation, or none of these. Significance of p=.01 was used to account for multiple comparisons., Results: Four hundred forty-five surgeons (18%) completed the survey. Surgeons in practice for 15+ years were more likely to select revision microdiscectomy compared with surgeons with fewer years in practice who were more likely to select revision microdiscectomy with PLIF/TLIF (p<.001). Similarly, those surgeons performing 200+ surgeries per year were more likely to select revision microdiscectomy with PLIF/TLIF than those performing fewer surgeries (p=.003). No significant differences were identified for region, specialty, fellowship training, or practice type. Overall, there was a 69% and 22% probability that two randomly selected spine surgeons would disagree on the surgical treatment of two- and one-time recurrent disc herniations, respectively. This probability of disagreement was consistent over multiple variables including geographic, practice type, fellowship training, and annual case volume., Conclusions: Significant differences exist among US spine surgeons in the surgical treatment of recurrent lumbar disc herniations. It will become increasingly important to understand the underlying reasons for these differences and to define the most cost-effective surgical strategies for these common lumbar pathologies as the United States moves closer to a value-based health-care system., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Purpose: To compare images acquired with 50% tube exposure with a dual-source computed tomographic (CT) scanner and reconstructed with sinogram-affirmed iterative reconstruction (SAFIRE) with 100% exposure images reconstructed with filtered back projection (FBP) for reader ability to detect stones, reader confidence, and findings outside the urinary tract., Materials and Methods: In this HIPAA-compliant, institutional review board-approved study, imaging examinations in 99 patients with urolithiasis were assessed. Data from both tubes were reconstructed with FBP; data from the primary tube only were reconstructed with SAFIRE. Seven readers evaluated randomized studies for calculi in nine regions. Reader confidence was scored by using a five-point scale. Ancillary findings were noted. Nonparametric methods for clustered data were used to estimate the area under the receiver operating characteristic curves with 95% confidence intervals to test for noninferiority of 50% exposure with SAFIRE., Results: Calculi were found in 113 locations (pyelocalyceal ureter, 86; proximal ureter, seven; midureter, four; distal ureter, 15; bladder, one) and not found in 752 locations. Mean area under the receiver operating characteristic curve for FBP was 0.879 (range, 0.607-0.967) and for SAFIRE, 0.883 (range, 0.646-0.971; 95% confidence interval: -0.025, 0.031). The SAFIRE images were not significantly inferior to FBP images (P = .001). Reader confidence levels for images with stones were similar with FBP and SAFIRE (P = .963). For the 52 patients who had extraurinary findings, readers reported them correctly in 74.4% (271 of 364) and 72.0% (262 of 364) of cases (P = .215) for FBP and SAFIRE, respectively. For the nine patients with potentially important findings per the reference standard, the detection rates were 44% (28 of 63) and 33% (21 of 63, P = .024), respectively. For the 43 patients with unimportant or likely unimportant findings, the false detection rates were 15% (44 of 301) and 14% (43 of 301, P = .756), respectively., Conclusion: The 50% tube exposure CT images reconstructed with SAFIRE were not inferior to 100% exposure images reconstructed with FBP for diagnosis of urolithiasis, without decreases in reader confidence.

Objective: This study aimed to assess the accuracy and operating characteristics of the Patient Health Questionnaire-9 (PHQ-9) for depression screening in adults with epilepsy., Methods: Tertiary epilepsy center patients served as the study population, with 237 agreeing to structured interview using the Mini-International Neuropsychiatric Interview (MINI), a "gold standard" instrument developed for rapid diagnosis of neuropsychiatric disorders, including major depressive disorder (MDD); 172 also completed the PHQ-9, and 127 completed both the PHQ-9 and the Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) within two days of the MINI. Sensitivity, specificity, positive and negative predictive values, and areas under the ROC curves for each instrument were determined. Cut-points of 10 for the PHQ-9 and 15 for the NDDI-E were used, and ratings at or above the cut-points were considered screen-positive. The PHQ-9 was divided into cognitive/affective (PHQ-9/CA) and somatic (PHQ-9/S) subscales to determine comparative depression screening accuracy., Results: The calculated areas under the ROC curves for the PHQ-9 (n=172) and the PHQ-9/CA and PHQ-9/S subscales were 0.914, 0.924, and 0.846, respectively, with the PHQ-9 more accurate than the PHQ-9/S (p=0.002) but not different from the PHQ-9/CA (p=0.378). At cut-points of 10 and 15, respectively, the PHQ-9 had higher sensitivity (0.92 vs 0.87) but lower specificity (0.74 vs 0.89) compared with the NDDI-E. The areas under the ROC curves of the PHQ-9 and the NDDI-E showed similar accuracy (n=127; 0.930 vs 0.934; p=0.864)., Significance: The PHQ-9 is an efficient and nonproprietary depression screening instrument with excellent accuracy validated for use in adult patients with epilepsy as well as multiple other medical populations., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Rationale and Objectives: To evaluate whether the presence of facial photographs obtained at the point-of-care of portable radiography leads to increased detection of wrong-patient errors., Materials and Methods: In this institutional review board-approved study, 166 radiograph-photograph combinations were obtained from 30 patients. Consecutive radiographs from the same patients resulted in 83 unique pairs (ie, a new radiograph and prior, comparison radiograph) for interpretation. To simulate wrong-patient errors, mismatched pairs were generated by pairing radiographs from different patients chosen randomly from the sample. Ninety radiologists each interpreted a unique randomly chosen set of 10 radiographic pairs, containing up to 10% mismatches (ie, error pairs). Radiologists were randomly assigned to interpret radiographs with or without photographs. The number of mismatches was identified, and interpretation times were recorded., Results: Ninety radiologists with 21 ± 10 (mean ± standard deviation) years of experience were recruited to participate in this observer study. With the introduction of photographs, the proportion of errors detected increased from 31% (9 of 29) to 77% (23 of 30; P = .006). The odds ratio for detection of error with photographs to detection without photographs was 7.3 (95% confidence interval: 2.29-23.18). Observer qualifications, training, or practice in cardiothoracic radiology did not influence sensitivity for error detection. There is no significant difference in interpretation time for studies without photographs and those with photographs (60 ± 22 vs. 61 ± 25 seconds; P = .77)., Conclusions: In this observer study, facial photographs obtained simultaneously with portable chest radiographs increased the identification of any wrong-patient errors, without substantial increase in interpretation time. This technique offers a potential means to increase patient safety through correct patient identification., (Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.)

Objectives: To assess the effectiveness of computer-aided detection (CAD) as a second reader or concurrent reader in helping radiologists who are moderately experienced in computed tomographic colonography (CTC) to detect colorectal polyps., Methods: Seventy CTC datasets (34 patients: 66 polyps ≥6 mm; 36 patients: no abnormalities) were retrospectively reviewed by seven radiologists with moderate CTC experience. After primary unassisted evaluation, a CAD second read and, after a time interval of ≥4 weeks, a CAD concurrent read were performed. Areas under the receiver operating characteristic (ROC) curve (AUC), along with per-segment, per-polyp and per-patient sensitivities, and also reading times, were calculated for each reader with and without CAD., Results: Of seven readers, 86% and 71% achieved a higher accuracy (segment-level AUC) when using CAD as second and concurrent reader respectively. Average segment-level AUCs with second and concurrent CAD (0.853 and 0.864) were significantly greater (p < 0.0001) than average AUC in the unaided evaluation (0.781). Per-segment, per-polyp, and per-patient sensitivities for polyps ≥6 mm were significantly higher in both CAD reading paradigms compared with unaided evaluation. Second-read CAD reduced readers' average segment and patient specificity by 0.007 and 0.036 (p = 0.005 and 0.011), respectively., Conclusions: CAD significantly improves the sensitivities of radiologists moderately experienced in CTC for polyp detection, both as second reader and concurrent reader., Key Points: • CAD helps radiologists with moderate CTC experience to detect polyps ≥6 mm. • Second and concurrent read CAD increase the radiologist's sensitivity for detecting polyps ≥6 mm. • Second read CAD slightly decreases specificity compared with an unassisted read. • Concurrent read CAD is significantly more time-efficient than second read CAD.

Purpose: To measure the effect of reduced radiation exposure on low-contrast low-attenuation liver lesion detection in an anthropomorphic abdominal phantom by using filtered back projection (FBP) and sinogram-affirmed iterative reconstruction., Materials and Methods: Eighteen radiologists blinded to phantom and study design interpreted randomized image data sets that contained 36 spherical simulated liver lesions of three sizes and three attenuation differences (5-mm diameter: 12, 18, and 24 HU less than the 90-HU background attenuation of the simulated liver insert; 10- and 15-mm diameter: 6, 12, and 18 HU less than the 90-HU background attenuation) scanned with four discrete exposure settings and reconstructed by using FBP and sinogram-affirmed iterative reconstruction. Response assessment included region-level lesion presence or absence on a five-point diagnostic confidence scale. Statistical evaluation included multireader multicase receiver operating characteristic curve analysis, with nonparametric methods and noninferiority analysis at a margin of -0.10., Results: Pooled accuracy at 75% exposure for both FBP and sinogram-affirmed iterative reconstruction was noninferior to 100% exposure (P = .002 and P < .001, respectively). Subsequent exposure reductions resulted in a significant decrease in accuracy. When the smallest (5-mm-diameter) lesions were excluded from analysis, sinogram-affirmed iterative reconstruction was superior to FBP at 100% exposure (P = .011), and sinogram-affirmed iterative reconstruction at 25% and 50% exposure reduction was noninferior to FBP at 100% exposure (P ≤ .013). Reader confidence was greater with sinogram-affirmed iterative reconstruction than with FBP for 10- and 15-mm lesions (2.94 vs 2.76 and 3.62 vs 3.52, respectively)., Conclusion: In this low-contrast low-attenuation liver lesion model, a 25% exposure reduction maintained noninferior diagnostic accuracy. However, detection was inferior with each subsequent exposure reduction, regardless of reconstruction method. Sinogram-affirmed iterative reconstruction and FBP performed equally well at modest exposure reduction (25%-50%). Readers had higher confidence levels with sinogram-affirmed iterative reconstruction for the 10- and 15-mm lesions., (© RSNA, 2014.)

The primary objectives of this study were to determine how frequently knee magnetic resonance imaging (MRI) changes (1) diagnosis, (2) diagnostic confidence, and (3) management. A secondary objective was to correlate these changes with specific patient/physician characteristics and develop a prediction model using these characteristics. Six orthopedic specialists prospectively completed surveys when ordering knee MRI (n=93). Pre-MRI surveys recorded history, symptoms, signs, diagnosis, diagnostic confidence, and planned management. Post-MRI surveys recorded diagnosis, confidence, and planned management. Changes in diagnosis, management, and diagnostic confidence were correlated with patient/physician characteristics using chi-square and logistic regression tests. A multiple variable model was created with the most significant variables from the univariate analysis, and a c-index was used for cross-validation. Magnetic resonance imaging changed diagnosis in 29.3% and management in 25.3% of cases. Confidence in diagnoses after MRI increased, on average, by 10.6%. Change in diagnosis was significantly correlated with lateral joint line pain (P=.012) and tenderness (P=.006). The 3 most significant predictors for change in management were ligament pathology (P=.017), medial-sided pain/tenderness (P=.051), and age (P=.133). A 3-variable model using these predictors was significantly better than chance alone at predicting management changes (c-index: model=0.766; cross-validation=0.661). Magnetic resonance imaging frequently changed diagnosis and management and improved diagnostic confidence in a large minority of patients with internal derangement of the knee, even after evaluation by subspecialized physicians. A statistical model using specific patient characteristics can be created to predict when MRI will change management., (Copyright 2014, SLACK Incorporated.)

Rationale and Objectives: Delays between order and magnetic resonance (MR) exam often result when using the conventional paper-based MR safety screening process. The impact of an electronic MR safety screening process imbedded in a computerized physician order entry (CPOE) system was evaluated., Materials and Methods: Retrospective chart review of 4 months of inpatient MR exam orders and reports was performed before and after implementation of electronic MR safety documentation. Time from order to MR exam completion, time from MR exam completion to final radiology report, and time from first order to final report were analyzed by exam anatomy. Length of stay (LOS) and date of service within the admission were also analyzed., Results: We evaluated 1947 individual MR orders in 1549 patients under an institutional review board exemption and a waiver of informed consent. Implementation of the electronic safety screening process resulted in a significant decrease of 1.1 hours (95% confidence interval 1.0-1.3 hours) in the mean time between first order to final report and a nonsignificant decrease of 0.8 hour in the median time from first order to exam end. There was a 1-day reduction (P = .697) in the time from admission to the MR exam compared to the paper process. No significant change in LOS was found except in neurological intensive care patients imaged within the first 24 hours of their admission, where a mean 0.9-day decrease was found., Conclusion: Benefits of an electronic process for MR safety screening include enabling inpatients to have decreased time to MR exams, thus enabling earlier diagnosis and treatment and reduced LOS., (Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.)

Background: High levels of humeral torsion allow baseball pitchers to achieve maximum external rotation in the late cocking phase of pitching with lower twisting and shear forces on the long head of the biceps tendon and rotator cuff tendons., Hypothesis: Humeral torsion is inversely related to the incidence and severity of shoulder injuries and other upper extremity injuries in professional baseball pitchers., Study Design: Case-control study; Level of evidence, 3., Methods: A total of 25 professional pitchers from a single Major League Baseball organization were prospectively recruited into this study. Computed tomography (CT) was performed on dominant and nondominant humeri, and image data were processed with a 3-dimensional volume-rendering postprocessing program. The software program was then modified to model a simplified throwing motion and to measure potential internal impingement distances in a small subset of players. Players were followed for 2 years after CT, and the number of days missed from pitching activities was recorded as a measure of injury severity and incidence., Results: The mean dominant humeral torsion was 38.5° ± 8.9°; the mean nondominant humeral torsion was 27.6° ± 8.0°. The difference between dominant and nondominant torsions was significant (P < .0001). Among the 11 pitchers (44%) injured during follow-up, 5 players had shoulder injuries, 7 had elbow injuries, and 2 had finger injuries. Dominant humeral torsion was a statistically significant predictor of severe injuries (≥30 days; P = .048) but not of milder injuries. Among injured players, higher numbers of days missed because of injury were strongly correlated with lower degrees of dominant humeral torsion (r = -0.78; P = .005) and smaller differences between dominant and nondominant humeral torsions (r = -0.59; P = .055). There was no significant association between the incidence of shoulder injury and minimum glenoid-tuberosity distance in the dominant or nondominant shoulder or degree of dominant glenoid version., Conclusion: A strong relationship was found between lower degrees of dominant humeral torsion and more severe upper extremity injuries as well as a trend relating lower side-to-side differences in torsion with more severe dominant upper extremity injuries. In addition, there was a higher incidence of severe injuries in players with lower degrees of dominant torsion. If future studies confirm these results, humeral torsion measurements could play a role in risk assessment in pitchers.

Objective: To identify independent predictors of malignancy in Bosniak III (BIII) renal lesions and to build a prediction model based on readily identifiable clinical variables., Methods: In this institutional review board-approved, Health Insurance Portability and Accountability Act (HIPAA)-compliant retrospective study, radiology, and hospital information systems containing data from January 1, 1994, to August 31, 2009, were queried for adult patients (age >18 years) with surgically excised BIII lesions. Clinical variables and results of histopathology were noted. Univariate and multiple-variable logistic regression analyses were performed to identify potential predictors and to build a prediction model. Cross-validation was used to assess generalizability of the model's performance, as characterized by concordance (c) index., Results: Of the 107 lesions in 101 patients, 59 were malignant and 48 benign. On univariate analyses, the strongest potential predictors of malignancy were African American race (P = .043), history of renal cell carcinoma (RCC; P = .026), coexisting BIII lesions (P = .032), coexisting Bosniak IV (BIV) lesions (P = .104), body mass index (BMI; P = .078), and lesion size (P <.001). A model with lesion size (odds ratio [OR] = 0.69; 95% confidence interval [CI] 0.58-0.82), history of RCC (9.02; CI 0.99-82.15), and BMI (OR 1.1; 95% CI 0.99-1.19) offered the best performance with a c-index after cross-validation of 0.719. Using an estimated probability of malignancy of >80%, the positive predictive value of the model is 92% (CI 78%-100%)., Conclusion: Clinical risk factors offer modest but definite predictive ability for malignancy in BIII lesions. In particular, a prediction model encompassing lesion size, BMI, and history of RCC seems promising. Further refinements with possible inclusion of imaging biomarkers and validation on an independent dataset are desirable., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: Epsilon aminocaproic acid (EACA) has been used in the past to prevent cerebral aneurysm rerupture. Recent studies have indicated that short-term treatment with EACA can lower rebleeding rates without significantly increasing ischemic or thrombotic complications or permanent shunt rates. The goal of this study is to determine the efficacy of EACA in the prevention of aneurysm rerupture at a high volume subarachnoid hemorrhage center., Methods: We conducted a retrospective study of 355 consecutive subarachnoid hemorrhage patients over a 2-year period under our current protocol for EACA use. Patients were divided by presentation time to our institution and whether the patient received EACA. The primary endpoints of the study were rebleeding rates, ischemic complications, thrombotic complications, vasospasm, shunt rates, and outcomes., Results: Rerupture rates were reduced by half in the entire pool of patients on EACA after controlling for Hunt and Hess Scores and Fisher Scores. In patients who received early aneurysm treatment, this effect persisted but was non-statistically significant due to the small numbers of reruptures. In addition, there was no evidence to suggest that EACA increased ischemic or thrombotic complications, vasospasm, or VPS rates. In patients presenting earlier than 24 h to our institution, there was a non-significant trend toward worse outcomes after EACA use. This trend was reversed in patients arriving after 24 h., Conclusion: There is evidence to suggest that EACA is protective from aneurysm rerupture without significant ischemic or thrombotic complications when used for less than 72 h. However, if the aneurysm is treated, this effect is modest indicating that early aneurysm treatment remains the gold standard for rerupture prevention.

Objective: The purpose of this study was to determine the reach, appeal, and learning effectiveness of a Web-based pediatric radiology curriculum with attention to level of training, test format, program size, subspecialty, and country of study., Materials and Methods: Registration demographics, the 10-point evaluation form, and pre- and posttest scores from approximately 17,000 modules completed from October 2011 to July 2012 were analyzed., Results: There were 20,583 registered users from 298 institutions, 43 states and Puerto Rico, and 53 countries, with on average 256 new registrants each year. Evaluation scores were 3.30-4.16 of 5 points. Small programs benefited most with an average improvement of 16.78%, with an average improvement of 16.31% for medium and large programs (p < 0.001). First-year residents showed greatest improvement (18.15%), followed by second-year (16.74%), third-year (16.16%), and fourth-year (12.94%) residents. Radiology residents showed greater improvement (16.63%) over others collectively (16.21%), dependent on job training (p < 0.0001). Average improvement for true/false versus multiple-choice tests was 15.53% and 26.00%, respectively (p < 0.0001). Improvement was higher for international (16.91%) than North American (16.43%) users, with all modules showing improvement with similar trends for all modules; however, the pretest average was higher for United States and Canada than for the rest of the world (63.67% vs 61.92%). Mean improvement over all modules was 16.45% (SD, 18.36%) with 95% confidence interval of 16.18%-16.73% (p < 0.001)., Conclusion: The pediatric radiology curriculum is universally popular both within North America and internationally, easy to use and enjoyable, and effective for learners at all levels within radiology and allied fields. In addition, it serves as an excellent springboard for future development of more sophisticated learning tools.

Rationale and Objectives: Multireader imaging trials often use a factorial design, in which study patients undergo testing with all imaging modalities and readers interpret the results of all tests for all patients. A drawback of this design is the large number of interpretations required of each reader. Split-plot designs have been proposed as an alternative, in which one or a subset of readers interprets all images of a sample of patients, while other readers interpret the images of other samples of patients. In this paper, the authors compare three methods of analysis for the split-plot design., Materials and Methods: Three statistical methods are presented: the Obuchowski-Rockette method modified for the split-plot design, a newly proposed marginal-mean analysis-of-variance approach, and an extension of the three-sample U-statistic method. A simulation study using the Roe-Metz model was performed to compare the type I error rate, power, and confidence interval coverage of the three test statistics., Results: The type I error rates for all three methods are close to the nominal level but tend to be slightly conservative. The statistical power is nearly identical for the three methods. The coverage of 95% confidence intervals falls close to the nominal coverage for small and large sample sizes., Conclusions: The split-plot multireader, multicase study design can be statistically efficient compared to the factorial design, reducing the number of interpretations required per reader. Three methods of analysis, shown to have nominal type I error rates, similar power, and nominal confidence interval coverage, are available for this study design., (Copyright © 2012 AUR. All rights reserved.)

Objective: The purpose of this article is to evaluate the effect of sinogram-affirmed iterative reconstruction (SAFIRE) on contrast-to-noise ratio (CNR) compared with filtered back projection (FBP) and to determine whether SAFIRE improves low-contrast object detection or conspicuity in a low-contrast object phantom and in the liver on full- and low-dose examinations., Subjects and Methods: A low-contrast object phantom was scanned at 100%, 70%, 50%, and 30% dose using a single-source made of a dual-source MDCT scanner, with the raw data reconstructed with SAFIRE and FBP. Unenhanced liver CT scans in 22 patients were performed using a dual-source MDCT. The raw data from both tubes (100% dose) were reconstructed using FBP, and data from one tube (50% dose) were reconstructed using both FBP and SAFIRE. CNR was measured in the phantom and in the liver. Noise, contrast, and CNR were compared using paired Student t tests. Six readers assessed sphere detection and conspicuity in the phantom and liver-inferior vena cava conspicuity in the patient data. The phantom and patient data were assessed using multiple-variable logistic regression., Results: The phantom at 70% and 50% doses with SAFIRE had decreased noise and increased CNR compared with the 100% dose with FBP. In the liver, the mean CNR improvement at 50% dose with SAFIRE compared with FBP was 31.4% and 88% at 100% and 50% doses, respectively (p < 0.001). Sphere object detection and conspicuity improved with SAFIRE (p < 0.001). However, smaller spheres were obscured on both FBP and SAFIRE images at lower doses. Liver-vessel conspicuity improved with SAFIRE over 50%-dose FBP in 67.4% of cases (p < 0.001), and versus 100%-dose FBP, improved in 38.6% of cases (p = 0.085). As a predictor for detection, CNR alone had a discriminatory ability (c-index, 0.970) similar to that of the model that analyzed dose, lesion size, attenuation difference, and reconstruction technique (c-index, 0.978)., Conclusion: Lower dose scans reconstructed with SAFIRE have a higher CNR. The ability of SAFIRE to improve low-contrast object detection and conspicuity depends on the radiation dose level. At low radiation doses, low-contrast objects are invisible, regardless of reconstruction technique.

Background: Accurate assessment of right ventricular (RV) size (RVS) and RV systolic function (RVSF) is vital in the management of various conditions, but their assessment is challenging using echocardiography. The aim of this study was to determine the accuracy and interobserver concordance of qualitative and quantitative RV echocardiography., Methods: Fifteen readers evaluated RV function in 12 patients (360 readings) who underwent echocardiography and cardiac magnetic resonance for RV assessment. Readers qualitatively estimated RVS and RVSF as normal, mild, moderate, or severe and then reassessed quantitatively by adding RV dimensions, fractional area change, S', tricuspid annular plane systolic excursion, and RV index of myocardial performance. Cardiac magnetic resonance was used as the reference standard for grading RVS and RVSF., Results: Quantitative measurements increased accuracy and interreader agreement compared to qualitative assessment alone, especially in normal categories. Readers' accuracy for diagnosing normal and severe RVS increased from 38% to 78% (P = .001) and from 70% to 97% (P = .018), and readers' accuracy for diagnosing normal and mild RVSF increased from 52% to 84% (P < .001) and from 36% to 56% (P = .001). Interreader agreement for classification of the subjects as normal or abnormal improved from a κ value of 0.40 to 0.77 (fair to good agreement) for RVS and from 0.43 to 0.66 (moderate to good agreement) for RVSF., Conclusions: Visual estimation of RVS and RVSF is inaccurate and has wide interobserver variability. Quantitation improves accuracy and reliability, especially in distinction of normal and abnormal. The reliability of mild and moderate grades remains inadequate, and further guidance is needed for the classification of abnormal categories., (Copyright © 2012 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.)

Objective: The objective of our study was to determine the accuracy of MRI in diagnosing meniscal tears in older patients and the frequency with which abnormal MRI findings correlate with degeneration, fraying, and tears at arthroscopy., Materials and Methods: Ninety-two patients 50 years old or older who had undergone knee MRI followed by knee arthroscopy within 6 months were selected. Menisci were graded on a 5-point scale: 1, definitely no tear; 2, probably no tear; 3, indeterminate or equivocal; 4, probably a tear; and 5, definitely a tear. Meniscal signal changes, meniscal surface morphology, and extrameniscal abnormalities were noted. Operative notes were reviewed, and the sensitivity and specificity of MRI results were calculated., Results: For medial tears, MRI had a sensitivity and specificity of 0.91 and 0.94, respectively, when grade 5 was considered a tear, 0.96 and 0.76 when grades 4 and 5 were considered a tear, and 0.99 and 0.47 when grades 3-5 were considered a tear. For lateral tears, MRI had a sensitivity and specificity of 0.73 and 0.91 when grade 5 was considered a tear, 0.88 and 0.80 when grades 4 and 5 were considered a tear, and 1.0 and 0.61 when grades 3-5 were considered a tear. The positive predictive values (PPVs) of MRI for the medial meniscus were 99%, grade 5; 57%, grade 4; 29%, grade 3; 25%, grade 2; and 0%, grade 1. For the lateral meniscus, the PPVs of MRI were 76%, grade 5; 36%, grade 4; 19%, grade 3; and 0%, grades 1 and 2., Conclusion: The accuracy of MRI for diagnosing meniscal tears in older patients is high and similar to that in younger patients when only definitive findings are considered a tear. The specificity decreases if equivocal or probable findings are considered a tear.

Objective: The purpose of this study is to evaluate the performance of gadoxetate disodium-enhanced MRI in the characterization of focal nodular hyperplasia (FNH) and hepatocellular adenoma and to assess potential advantages of hepatocyte phase imaging in identifying features that distinguish FNH from hepatocellular adenoma., Materials and Methods: Gadoxetate disodium-enhanced MRI examinations of 12 patients with hepatocellular adenoma and 35 patients with FNH were retrospectively evaluated by three blinded readers. Diagnoses and confidence scores were recorded before and after disclosure of hepatocyte phase images. The data obtained were combined to create receiver operating characteristic curves, and the areas under the curves were compared. Imaging characteristics, including signal intensity, were recorded. Lesion-to-liver enhancement ratio was calculated for each contrast-enhanced phase., Results: The readers' average receiver operating characteristic area was significantly higher after disclosure of hepatocyte phase images (p=0.024). FNHs were correctly diagnosed in 74.3-97.1% of cases before and 97.1-100% of cases after the disclosure of hepatocyte phase images; hepatocellular adenoma was correctly diagnosed in 83-100% and 91.7-100% of cases (p>0.05). The presence of a central scar in FNH and fat on hepatocellular adenoma were the only morphologic features that were statistically significantly different (p<0.05). FNH had greater average contrast-enhanced signal intensity and enhancement ratio in all phases (p<0.001). A hepatocyte phase enhancement ratio of less than 0.7 was 100% specific and 91.6% sensitive for hepatocellular adenoma, with accuracy of 97.1% for these data., Conclusion: Gadoxetate disodium-enhanced MRI had high accuracy in diagnosis of FNH and hepatocellular adenoma, and the hepatocyte phase improved their distinction. FNH enhances significantly more than hepatocellular adenoma. An enhancement ratio, particularly in the hepatocyte phase, can be potentially used as an additional distinguishing feature.

Rationale and Objectives: Before computer-aided detection (CAD) algorithms can be used in clinical practice, they must be shown to improve readers' diagnostic accuracy over their unaided performance. This is usually accomplished through a large multireader, multicase (MRMC) clinical trial. It is burdensome, however, for an MRMC study to be performed with each new release of a CAD algorithm. The aim of this report is to present an approach for building models to predict readers' accuracy with a new CAD algorithm., Materials and Methods: A modeling approach for predicting readers' results with a new CAD algorithm is described. Multiple-variable logistic regression was used to build models for readers' sensitivity and false-positive rate, given the results of an MRMC study with an older CAD algorithm and the stand-alone performance results of a new CAD algorithm. Data from a large lung MRMC CAD trial are used to illustrate the modeling approach and test the ability of the models to predict readers' accuracy with the new CAD algorithm., Results: The model overestimated the readers' actual sensitivity with the new CAD algorithm, but this did not reach statistical significance (0.621 vs 0.603, P = .147). The observed and predicted false-positive rates also did not differ significantly (0.275 vs 0.285, P = .250)., Conclusions: Using one clinical study as a test case, it is shown that the modeling approach is feasible. More testing of the approach is needed to determine if and under what circumstances it can be used as an alternative to a full-scale MRMC study. Meanwhile, the approach can be used to determine if a new CAD algorithm is likely to improve readers' accuracy before embarking on a full-scale MRMC study., (Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.)

Objective: Calculating the sample size for a multireader, multicase study of readers' diagnostic accuracy is complicated. Studies in which patients can have multiple findings, as is common in many computer-aided detection (CAD) studies, are particularly challenging to design., Materials and Methods: We modified existing methods for sample size estimation for multireader, multicase studies to accommodate multiple findings on the same case. We use data from two large multireader, multicase CAD studies as ballpark estimates of parameter values., Results: Sample size tables are presented to provide an estimate of the number of patients and readers required for a multireader, multicase study with multiple findings per case; these estimates may be conservative for many CAD studies. Two figures can be used to adjust the number of readers when there is some data on the between-reader variability., Conclusion: The sample size tables are useful in determining whether a proposed study is feasible with the available resources; however, it is important that investigators compute sample size for their particular study using any available pilot data.

Objective: The purpose of this study was to evaluate the diagnostic performance of sampling perfection with application-optimized contrasts using different flip-angle evolutions (SPACE) 3D fast spin-echo acquisition relative to conventional 2D fast spin-echo acquisition in the 3-T MRI evaluation of the menisci and ligaments of the knee., Materials and Methods: Images from all MRI knee examinations performed with a single 3-T system from September 2008 to January 2009 were reviewed. Seventy-one examinations of patients who subsequently underwent knee arthroscopy and an additional 29 examinations of patients who did not undergo surgery were selected for a total of 100 examinations. All imaging was performed with multiplanar conventional 2D and SPACE 3D fast spin-echo acquisitions. Six musculoskeletal radiologists independently reviewed the images. Area under the receiver operating characteristic (ROC) curve was calculated for the menisci and anterior cruciate ligament with arthroscopy as the reference standard. Disagreement between the two acquisitions was calculated for the posterior cruciate ligament and medial and lateral collateral ligaments. The Wilcoxon signed rank test was used to compare each reader's confidence scores for the two techniques., Results: For the medial meniscus, the average area under the ROC curve was statistically significantly larger (p = 0.01) with the conventional 2D (0.931) than with the SPACE 3D (0.893) technique. Average confidence in diagnosing medial meniscal tears also was statistically significantly greater with the 2D than with the 3D technique (p = 0.001). No statistically significant differences were found for the lateral meniscus or anterior cruciate ligament. The rate of discordance between findings with the 2D and 3D techniques was low for the posterior cruciate ligament and medial and lateral collateral ligaments (range, 4.2-5.7%)., Conclusion: In evaluation of menisci with 3-T MRI, readers performed better with conventional 2D acquisition than with SPACE 3D acquisition. In evaluation of ligaments, the readers had similar performance with the two acquisition methods.

Objective: The primary objective of our study was to compare the effect of a chest radiography computer-aided detection (CAD) system on the follow-up recommendations of chest radiologists, general radiologists, and pulmonologists., Materials and Methods: A chest radiography CAD system (RapidScreen 1.1) that has been approved by the U.S. Food and Drug Administration (FDA) and a second-generation version of the system (OnGuard 3.0) not yet approved by the FDA were applied to single frontal radiographs of 200 patients at high risk for lung cancer. One hundred patients had actionable nodules (mean size, 16.9 mm) and 100 patients did not. Six chest radiologists, six general radiologists, and six pulmonologists independently interpreted each image first without CAD and then with CAD during blinded reading sessions. The frequency with which readers correctly referred patients for follow-up tests was measured. Differential effects based on nodule size, shape, location, density, and subtlety were tested with multiplevariable logistic regression., Results: For patients without actionable lesions, pulmonologists showed an increase in their recommendations for follow-up from 0.46 unaided to 0.52 with CAD (p = 0.001), whereas chest and general radiologists had much lower average rates and were not affected by CAD's false marks (0.26 without CAD vs 0.25 with RapidScreen 1.1 and 0.26 with OnGuard 3.0, p ≥ 0.734). CAD improved all readers' detection of moderately subtle lesions (p = 0.013) but did not significantly increase follow-up rates overall for patients with actionable nodules (0.63 unaided vs 0.63 with RapidScreen 1.1, p = 0.795; and 0.63 unaided vs 0.64 with OnGuard 3.0, p = 0.187)., Conclusion: The effect of CAD on readers' clinical decisions varies depending on the training of the reader. CAD did not improve the performance of chest or general radiologists. Nonradiologists are particularly vulnerable to CAD's false-positive marks.

Background: Intraprocedural rupture is a dangerous complication of endovascular treatment. Small ruptured anterior communicating artery (ACoA) aneurysms and microaneurysms present a challenge for both surgical and endovascular therapies to achieve obliteration. An understanding of the complication rates of treating ruptured ACoA microaneurysms may help guide therapeutic options., Objective: To report the largest cohort of ACoA microaneurysms treated with endovascular therapy over the course of the past 10 years., Methods: We performed a retrospective review of 347 ACoA aneurysms treated in 347 patients at Cleveland Clinic and Emory University over a 10-year period. Patient demographics, aneurysmal rupture, size, use of balloon remodeling, patient outcomes, intraprocedural rupture, and rerupture were reviewed., Results: Rupture rates were examined by size for all patients and subgroups and dichotomized to evaluate for size ranges associated with increased rupture rates. The highest risk of rupture was noted in aneurysms less than 4 mm. Of 347 aneurysms, 74 (21%) were less than 4 mm. The intraprocedural rupture rate was 5% (18/347) for ACoA aneurysms of any size. There was an intraprocedural rupture rate of 2.9% (8/273) among ACoA aneurysms greater than 4 mm compared with 13.5% (10/74) in less than 4-mm aneurysms. Procedural rupture was a statistically significant predictor of modified Rankin score after adjusting for Hunt and Hess grades (HH)., Conclusion: ACoA aneurysms less than 4 mm have a 5-fold higher incidence of intraprocedural rerupture during coil embolization. Outcome is negatively affected by intraprocedural rerupture after adjusting for HH grade.

Background: Antithrombotic states are encountered frequently, either because of medical therapy or by preexistent pathological states, and may affect the severity of hemorrhagic strokes such as angiographically negative subarachnoid hemorrhages., Objective: To determine the effects of antithrombotic states on the outcomes of patients with angiographically negative subarachnoid hemorrhage by examining data pooled from 2 institutions., Methods: This is a retrospective review of patients who experienced angiographically negative subarachnoid hemorrhage at 2 institutions over the past 5 years. The patients were grouped into those with and those without an antithrombotic state at time of hemorrhage and were stratified according to presentation, clinical grades, outcomes, need for cerebrospinal fluid diversion, and development of vasospasm. Computed tomography of the head was assessed for bleed pattern and modified Fisher grade. Patients were excluded if a causative lesion was subsequently discovered., Results: There is a statistically significant association between antithrombotic states and poorer presentation, higher Hunt and Hess score, increased amount of subarachnoid hemorrhage, higher modified Fisher grade, increased incidence of vasospasm, hydrocephalus, and poor outcomes as assessed by modified Rankin scale (P < .001). Patients with an antithrombotic state experience worse outcomes even with adjustment for the amount of hemorrhage as assessed by modified Fisher grade (P < .001)., Conclusion: Patients in an antithrombotic state presenting with angiographically negative subarachnoid hemorrhage present with inferior clinical scores, diffuse hemorrhage patterns, and worse modified Fisher grades and have worse outcomes.

Purpose: To assess the effect of using computer-aided detection (CAD) in second-read mode on readers' accuracy in interpreting computed tomographic (CT) colonographic images., Materials and Methods: The contributing institutions performed the examinations under approval of their local institutional review board, with waiver of informed consent, for this HIPAA-compliant study. A cohort of 100 colonoscopy-proved cases was used: In 52 patients with findings positive for polyps, 74 polyps of 6 mm or larger were observed in 65 colonic segments; in 48 patients with findings negative for polyps, no polyps were found. Nineteen blinded readers interpreted each case at two different times, with and without the assistance of a commercial CAD system. The effect of CAD was assessed in segment-level and patient-level receiver operating characteristic (ROC) curve analyses., Results: Thirteen (68%) of 19 readers demonstrated higher accuracy with CAD, as measured with the segment-level area under the ROC curve (AUC). The readers' average segment-level AUC with CAD (0.758) was significantly greater (P = .015) than the average AUC in the unassisted read (0.737). Readers' per-segment, per-patient, and per-polyp sensitivity for all polyps of 6 mm or larger was higher (P < .011, .007, .005, respectively) for readings with CAD compared with unassisted readings (0.517 versus 0.465, 0.521 versus 0.466, and 0.477 versus 0.422, respectively). Sensitivity for patients with at least one large polyp of 10 mm or larger was also higher (P < .047) with CAD than without (0.777 versus 0.743). Average reader sensitivity also improved with CAD by more than 0.08 for small adenomas. Use of CAD reduced specificity of readers by 0.025 (P = .05)., Conclusion: Use of CAD resulted in a significant improvement in overall reader performance. CAD improves reader sensitivity when measured per segment, per patient, and per polyp for small polyps and adenomas and also reduces specificity by a small amount., ((c) RSNA, 2010.)

Objective: The purpose of our study was to determine whether the MDCT enterography dose can be reduced by changing automatic exposure control (AEC) setting and quality reference milliampere-seconds (mAs) without altering subjective image quality or efficacy in active inflammatory Crohn's disease., Subjects and Methods: This is a prospective study of 2,310 MDCT enterography procedures performed using 16- and 64-MDCT in three cohorts (original, intermediate, and final dose levels). For 16-MDCT, the original and intermediate dose level quality reference mAs was 200, and weight-based (1 pound [0.45 kg] = 1 mAs) for the final dose level. For 64-MDCT, the original dose level quality reference mAs was 260; the mAs was 220 for intermediate and weight-based for the final dose level. For the intermediate and final dose levels, AEC was changed from strong to weak increase for obese and weak to strong decrease for slim patients. Demographic data and volume CT dose index (CTDI(vol)) were analyzed. Three readers evaluated the cases for image quality and efficacy differentiating normal from active inflammatory Crohn's disease., Results: For 16-MDCT, CTDI(vol) decreased from 12.82 to 10.14 mGy and 10.14 to 8.7 mGy between original to intermediate and intermediate to final dose levels. For 64-MDCT, the CTDI(vol) decreased from 15.72 to 11.42 mGy and 11.42 to 9.25 mGy between original to intermediate and intermediate to final dose levels. Images were rated suboptimal or nondiagnostic more often in the intermediate dose level (p < 0.05) but not in the final. There was no reduction in diagnostic efficacy as measured by area under the ROC curve (p > 0.1443 except for one comparison with one reader)., Conclusion: Substantial dose reduction can be achieved using weight-based quality reference mAs and altering AEC settings without affecting diagnostic efficacy in active inflammatory Crohn's disease of the terminal ileum. However, subjective image quality can be compromised at these dose settings, depending on radiologist preference.

Rationale and Objectives: The goal of many multiple-observer computer-aided detection (CADe) studies is to estimate the change in observers' diagnostic performance with CADe from their unaided performance. A key issue in these studies is the method for estimating the observers' unaided performance. The crossover design is considered the most valid. The sequential design takes less time and is less expensive but may be biased. We conducted a study to investigate the differences between these two designs., Materials and Methods: Data from two large CADe studies using both types of unaided reads were analyzed. The first study involved three radiologists examining the chest x-rays of 200 patients for lung nodules. The second study involved 19 observers interpreting the computed tomography colonography images of 100 patients for polyps. Observers' sensitivity, specificity, and receiver operating characteristic areas were estimated while unaided in both designs and compared to their accuracy with CADe. Bias, inter-observer variability, and correlations between unaided and aided results were assessed., Results: Observers tend to perform better while unaided in the sequential design than while unaided in the crossover design, but the differences are small. The inter-observer variability is larger in the sequential design. The correlations between unaided and aided results are larger in the sequential design. 95% CIs for the change with CADe are narrower with the sequential design., Conclusion: The estimated effect of CADe on observer performance is similar regardless of the study design. Use of the sequential design may save investigators time and resources., (Copyright (c) 2010 AUR. Published by Elsevier Inc. All rights reserved.)

Purpose: To determine whether the effectiveness of arterial embolization in patients with acute upper gastrointestinal hemorrhage is related to the visualization of contrast medium extravasation at angiography., Materials and Methods: Transcatheter embolization was performed in 108 patients who experienced acute upper gastrointestinal hemorrhage during a 5-year period. Patient charts were retrospectively reviewed. Thirty-six patients who underwent embolization after angiography demonstrated active contrast medium extravasation from an involved artery. Seventy-two patients underwent embolization in the absence of contrast medium extravasation into a bowel lumen. Embolization technique, requirement for further blood products, need for further surgery, and 30-day mortality were recorded., Results: The gastroduodenal artery (GDA) was embolized in 26 of the 36 patients (72%) with extravasation, and the left gastric artery was embolized in 10 (28%). The GDA was embolized in 64 of the 72 patients (89%) without extravasation, and the left gastric artery was embolized in 13 (18%). After embolization, 23 of the 36 patients (64%) with extravasation and 44 of the 72 (61%) without extravasation required additional blood product transfusions. Seven of the 36 patients (19%) with extravasation and 16 of the 72 (22%) without extravasation required subsequent surgery secondary to bleeding. Thirty-day hemorrhage-related mortality was 17% (six of 36 patients) in the positive extravasation group and 22% (16 of 72 patients) in the negative extravasation group. The treatment success rate was 44% (16 of 36 patients) in the positive extravasation group and 44% (32 of 72 patients) in the negative extravasation group., Conclusions: In patients with acute upper gastrointestinal hemorrhage, arterial embolization is equally effective in patients who demonstrate active contrast medium extravasation at angiography as in those who do not show contrast extravasation.

Purpose: To determine the safety and efficacy of real-time, sonographic-guided, random percutaneous needle biopsy of the liver in a tertiary medical center., Method: From an IRB-approved biopsy database, all patients who had random liver biopsy performed over a 24-month period were selected. In 350 patients, 539 random percutaneous needle biopsies of the liver were performed under real-time sonographic visualization. The following were recorded from the electronic medical record: patient demographics, indication for biopsy procedure; radiologist's name; needle type and gauge and number of passes; use and amount of i.v. sedation or anesthesia; adequacy of the specimen; and complications following the procedure., Result: Of 539 biopsies, 378 (70%) biopsy procedures were performed on liver transplant recipients. Of the biopsy procedures in nontransplant patients, 81/161 (50%) concurrently underwent biopsy of a focal liver mass. An 18-gauge automated core biopsy needle was used in 536/539 (99%). Median number of passes per biopsy procedure was 1 (mean, 1.7; range, 1-6). Sedation using midazolam and fentanyl was used in 483/539 (90%). There were only 8 inadequate specimens (1.5%, [2.3, upper 95% confidence limit, fully described in Statistical Analysis]). Complications were identified in 11/539 biopsy procedures (2.0%, [2.6, upper 95% confidence limit]): 5 with severe postprocedural pain, 3 with symptomatic hemorrhage, 2 with infection, and 1 with a rash. There were no sedation-related complications and no deaths related to the procedure., Conclusion: Real-time, sonographic-guided, random core-needle liver biopsy is a safe and highly effective procedure., (2009 Wiley Periodicals, Inc.)

Objective: The purpose of our study was to measure relative and absolute wall attenuations and wall thickness in normal small bowel on contrast-enhanced CT enterography and to study the efficacy of relative attenuation, absolute attenuation, and wall thickness in distinguishing normal from active inflammatory Crohn's disease of the terminal ileum., Materials and Methods: Using a case-control study design, we reviewed 630 CT enterography examinations, of which 191 were normal and 36 had active inflammatory Crohn's disease in the terminal ileum. In healthy individuals, wall thickness and attenuation in distended and collapsed loops were measured in the duodenum and four abdominal quadrants. Wall thickness and attenuation were also measured in the terminal ileum. All measurements of intraarterial attenuation were taken at the same slice level. In the examinations of patients with Crohn's disease, only terminal ileum wall thickness and attenuation as well as arterial attenuation at the same slice level were measured. Normal segments were compared with a linear model. Terminal ileum data were fit to a multivariate logistic regression model., Results: Relative attenuation and absolute attenuation in the normal distended and collapsed duodenum and left upper quadrant were significantly greater than in all other segments (p < 0.001 and < 0.048 for relative attenuation and p < 0.001 and < 0.032 for absolute attenuation, respectively). Relative attenuation and wall thickness models and absolute attenuation and wall thickness models discriminated normal from active terminal ileum Crohn's disease significantly better than the same measurements without wall thickness (p = 0.017 and 0.001, respectively). When the bowel wall is > 3 mm, a relative attenuation cutoff of 0.5 is 89% sensitive and 81% specific., Conclusion: In normal small bowel, when wall measurement is taken into account, the duodenum and jejunum have a greater relative attenuation and absolute attenuation than other segments. Relative attenuation and absolute attenuation with wall thickness models discriminate normal from active terminal ileum Crohn's disease better than the same measurements without wall thickness.

Rationale and Objectives: Multireader, multicase (MRMC) receiver-operating characteristic studies often require large numbers of patients, readers, and reader interpretations. The objective of this work is to evaluate a new "mixed" MRMC study design that reduces the number of reader interpretations., Materials and Methods: As compared to the traditional MRMC design, the number of reader interpretations and the number of cases that must be truth-verified for the new mixed design was evaluated theoretically and empirically for various correlation values and sample sizes., Results: For large MRMC studies, the new mixed design offers a substantial savings in the number of reader interpretations if the magnitude of the difference in between-reader correlations is not zero. For example, compared to a traditional design with 20 readers, 200 total cases, and a difference in between-reader correlations of 0.05, the newly proposed mixed design requires each reader to interpret only 132 cases, but at a cost of truth-verifying an additional 64 cases., Conclusions: The mixed design can reduce the number of cases that readers need to interpret and the overall duration of a study, but at a cost in terms of the number of cases that must be truth-verified. The mixed design is particularly useful for studies where the condition being detected is not rare and patients routinely undergo the gold standard assessment.

Unlabelled: The trend toward focused surgical parathyroidectomy requires precise preoperative localization of parathyroid lesions in patients with hyperparathyroidism. The purpose of this study was to directly compare the diagnostic accuracy of (99m)Tc-sestamibi/(123)I subtraction SPECT with SPECT/CT for the localization of abnormal parathyroid glands in patients with primary hyperparathyroidism., Methods: A total of 61 consecutive surgical patients with primary hyperparathyroidism underwent both (123)I/(99m)Tc-sestamibi subtraction SPECT and SPECT/CT scans preoperatively, using a hybrid SPECT/CT instrument that combined a dual-detector SPECT camera with a 6-slice multidetector spiral CT scanner. Four hours after being given (123)I-sodium iodide orally, each patient received (99m)Tc-sestamibi intravenously, followed immediately by a simultaneous, dual-isotope SPECT scan of the neck and upper chest. Then, without moving the patient, we performed a non-contrast-enhanced CT scan of the same body region. Normalization and subtraction of the (123)I SPECT images from the (99m)Tc SPECT images were performed. The subtraction SPECT and the coregistered fused SPECT/CT studies were interpreted separately, with images scored on a 5-point scale. Surgical and histopathologic findings were used as the standard of comparison., Results: Surgery was successful in 57 patients (solitary parathyroid adenoma in 48 patients, double parathyroid adenomas in 6 patients, and 10 hyperplastic parathyroid glands in 3 patients). The sensitivities of SPECT (50/70 = 71%) and SPECT/CT (49/70 = 70%) were similar (P = 0.779). The specificity of SPECT/CT (26/27 = 96%) was significantly greater than that of SPECT (13/27 = 48%; P = 0.006). The receiver-operating-characteristic area under the curve of SPECT/CT (0.833) was significantly greater than that of SPECT (0.632; P < 0.001)., Conclusion: SPECT/CT is significantly more specific than dual-isotope subtraction SPECT for the preoperative identification of parathyroid lesions in patients with primary hyperparathyroidism.

Background: Dual-source computed tomography (DSCT) was introduced with significant hardware and software changes compared with single-source CT (SSCT), resulting in improved temporal resolution (83 ms) and the potential for improved image quality. The effect of these changes on radiation dose requirements for coronary CT angiography in clinical practice has not been investigated., Objective: We evaluated patient radiation dose and image quality of electrocardiogram (ECG)-gated helical techniques, using DSCT compared with SSCT for clinical imaging of the coronary arteries., Methods: DSCT data from 160 patients were evaluated; 82 patients (DSCT group 1) were imaged with early software, and 78 patients (DSCT group 2) were imaged with a later software version. Patients imaged with SSCT (n = 124) were the control group. Effective radiation dose values were estimated for all patients. Image noise was measured, and image quality was evaluated on a 5-point scale., Results: Effective dose values for DSCT group 2 (11.7 +/- 4.0 mSv) were not different from those for SSCT group (10.9 +/- 2.9 mSv); the highest doses, 13.2 +/- 3.2 mSv, were recorded for DSCT group 1 (P < 0.001). A decrease in image noise was observed for DSCT compared with SSCT (P

Objective: The aim of this study was to determine if the presence of focal normal bone marrow fat signal within a tumor on magnetic resonance imaging excludes malignancy., Materials and Methods: One hundred eighty-four histologically proven tumors with available magnetic resonance imaging (MRI) of the appendicular skeleton and pelvis from 184 patients were collected and reviewed at two separate institutions. There were 111 malignant and 73 benign tumors. Two radiologists at each institution, blinded to the diagnosis, reviewed the MRIs independently and reported the presence or absence of normal marrow fat signal within the tumor based upon T1-weighted imaging without fat suppression and T2-weighted imaging with fat suppression and/or short inversion-time inversion recovery (STIR). Discrepancies were then reviewed in consensus to determine the presence or absence of focal normal marrow signal. For each institution, a Fisher's exact test was used to compare the frequency of focal normal marrow fat signal in benign and malignant tumors. This comparison was performed for each reader, as well as for the consensus reading at each site. Positive and negative predictive values were also calculated for each reader, as well as the consensus reading at each site. Fisher's exact test was also used to compare the frequency of intratumoral fat in benign and malignant lesions for the pooled sample. Bayes theorem was used to calculate the positive and negative predictive values for the pooled consensus data. Ninety-five percent confidence intervals were constructed for the pooled estimates using a bootstrapping algorithm., Results: There was good interobserver reliability of 95.3% and 96.7% at sites 1 and 2, respectively. There were three discrepancies (one malignant and two benign) at site 1 and four discrepancies (two malignant and two benign) at site 2. Reader consensus at site 1 identified normal marrow fat signal within 1 of 50 (2.0%) malignant and three of 14 (21.4%) benign tumors. Findings were statistically significant with a p value of 0.030. The positive predictive value (PPV) and negative predictive value (NPV) at site 1 was 81.7% and 75.0%, respectively. Reader consensus at site 2 identified normal marrow fat signal within three of 61 (4.9%) malignant and 14 of 59 (23.7%) benign tumors. Findings were statistically significant with a calculated p value of 0.004. The PPV and NPV at site 1 was 56.3% and 82.4%, respectively. For the pooled consensus, the frequency of intratumoral fat in benign lesions (17/73, 23.3%) is significantly greater than the frequency in malignant lesions (4/111, 3.6%), p < 0.001., Conclusion: The presence of focal normal marrow signal within a tumor is highly suggestive of a benign tumor.

Purpose: To retrospectively determine the frequency and severity of various abnormal laboratory test values following percutaneous cryoablation of liver tumors and to estimate the correlation between laboratory test values and tumor and ablation volumes., Materials and Methods: This HIPAA-compliant study had institutional review board approval. Informed consent was waived. Biochemical and hematologic laboratory values from 48 procedures in 39 patients (18 men and 21 women; age range, 29-86 years) who underwent magnetic resonance (MR) imaging-guided percutaneous cryoablation of 65 liver tumors (62 metastases, three hepatocellular carcinomas) were retrospectively reviewed. Changes in laboratory values at baseline and 0-6 hours and 1-2 weeks after the procedure were analyzed with respect to tumor and ablative margin volumes by using generalized estimating equations. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were correlated with percent maximal decrease in platelet count., Results: Mean ablation zone volume was 67.3 cm(3) +/- 41.2 (standard deviation) (range, 7.3-191.4 cm(3)). AST and ALT values increased after all procedures and peaked at 6 hours (median change in AST value, +835 U/L; median change in ALT value, +614.5 U/L). Platelet count decreased after 47 procedures (mean maximal decrease, 92.3 x 10(9)/L [38%]), reaching a nadir at 12-24 hours after 24 procedures (50%) and returning to normal in 31 (84%) of 37 procedures at 1-2 weeks. One procedure was complicated by disseminated intravascular coagulation that necessitated transfusion and arterial embolization. Myoglobin values increased after 21 (44%) of 48 procedures and peaked at 6 hours (trimmed-mean value, 183.4 mug/L). Ablative margin volumes were predictive of changes at 0-6 hours in AST (P = .02), ALT (P = .003), and myoglobin (P < .001) values. Percent maximal decrease in platelet count correlated with peak change in AST (r = 0.72) (P < .001)., Conclusion: Following percutaneous cryoablation of liver tumors, alterations in liver enzymes, myoglobin, and platelet count are common, are usually self-limited, and correlate with ablative margin volume--except for changes in platelet count, which correlate with changes in AST and ALT., ((c) RSNA, 2008.)

Background: Noninvasive characterization of coronary atherosclerotic plaque is limited with current computed tomography (CT) techniques. Dual-energy CT (DECT) has the potential to provide additional attenuation data for better differentiation of plaque components., Objective: We attempted to characterize coronary atherosclerotic plaque with DECT., Methods: Seven human coronary arteries acquired at autopsy were scanned consecutively at 80 and 140 kVp with CT. Vessels were perfused with saline, and data were acquired before and after contrast agent injection. Lesions were identified, and attenuation measurements were made from CT image quadrants. CT quadrants were classified as densely calcified, fibrocalcific, fibrous, lipid-rich, or normal vessel wall, corresponding to matched histology images. Attenuation values at each peak tube voltage were compared within plaque types for both noncontrast and contrast scans. Further, dual-energy index (DEI) values computed from attenuation were analyzed for classification of plaque., Results: In 14 lesions, a total of 56 quadrants were identified. Histology results classified 8 (14%) as densely calcified, 8 (14%) as fibrocalcific, 9 (16%) as fibrous, 5 (9%) as lipid-rich, and 25 (45%) as normal vessel wall. Calcified lesions attenuated significantly more at 80 kVp in both contrast and noncontrast scans, whereas fibrous plaque attenuated more at 80 kVp only for contrast-enhanced scans. No differences were found for lipid-rich plaques. Using DEI values, only densely calcified plaques could be distinguished from other plaque types except fibrocalcific plaques in contrast images., Conclusions: Only densely calcified and fibrocalcific plaques showed a true change in attenuation at 80 versus 140 kVp. Therefore, calcified plaques could be distinguished from noncalcified plaques with DECT, but further classification of plaque types was not possible.

Purpose: To determine whether using estimated glomerular filtration rate (eGFR) values rather than serum creatinine levels to identify patients with renal insufficiency facilitates any substantial change in the number of outpatients scheduled for computed tomography (CT) who are considered at increased risk for contrast medium-induced nephropathy., Materials and Methods: The study was HIPAA compliant and institutional review board approved for medical chart review; the requirement for informed patient consent was waived. Patients (n = 5138; 2569 women, 2569 men, 753 African Americans, 4385 non-African Americans) examined during a 2-year period formed the final study group after exclusion of patients undergoing dialysis (n = 49), for whom no age data were recorded (n = 9), and younger than 18 years (n = 113). Patient age, sex, and race and the blood urea nitrogen, albumin, and serum creatinine levels most recently measured within 6 months before CT were obtained from the electronic medical records. The number of patients with creatinine levels higher than 1.4 mg/dL was directly compared with the number of patients with eGFR values (calculated with four- and six-variable Modification of Diet in Renal Disease [MDRD] equations) lower than 60 mL/min/1.73 m(2) by using the two-tailed McNemar test. For 2689 patients, data to calculate the eGFR by using the four-variable equation were available, and for 2005 patients, data to calculate the eGFR by using the six-variable equation were available., Results: Among the outpatients scheduled to undergo CT, the percentage of patients with an eGFR lower than 60 mL/min/1.73 m(2) was significantly greater than the percentage of patients with a creatinine level higher than 1.4 mg/dL for both the four-variable (412 [15.3%] vs 166 [6.2%] of 2689 patients) and the six-variable (346 [17.3%] vs 117 [5.8%] of 2005 patients) MDRD equation groups (P < .001)., Conclusion: A significantly higher number of outpatients scheduled for contrast medium-enhanced CT met the National Kidney Foundation criteria for renal insufficiency when the MDRD equations were used to estimate the glomerular filtration rate compared with the number of outpatients who met the criteria on the basis of elevated creatinine levels., ((c) RSNA, 2008.)

Background: Lung cancer screening, like other screening tests, has the potential to save many lives, yet its benefit has not yet been shown in randomized clinical trials (RCTs). RCTs of screening tests require very large sample sizes and long follow-up periods. Investigators planning these trials need to know how the study design, particularly the length of accrual, the number of incident screens, the length of follow-up, and the method used to interpret the screening test, affect sample size requirements., Methods: In this paper a tiered approach to sample size estimation is presented. The first tier determines the person-years at risk; the second tier considers the characteristics of the study population to estimate the frequency of preclinical disease; the third tier uses the performance of the screening test, the compliance rate, and the benefits of early treatment to estimate the incidence of clinical disease; the disease-specific mortality rates are estimated in the fourth tier., Results: This sample size approach was utilized in planning a RCT of lung cancer screening with chest X-rays and a computer aided detection algorithm. Sample size was determined for various features of the study design, as well as for different assumptions about the cure rate, the treatment complication rate, and the rate of potential misclassification of the primary endpoints., Conclusion: The tiered approach to sample size estimation for RCTs of screening tests allows investigators to assess how features of the study design affect sample size requirements.

Background and Purpose: We conducted a prospective randomized study of patients with acute low back pain and/or radiculopathy to assess the effect of knowledge of diagnostic findings on clinical outcome. The practice of ordering spinal imaging, perhaps unintentionally, includes a large number of patients for whom the imaging test is performed for purposes of reassurance or because of patient expectations. If this rationale is valid, one would expect to see a measurable effect from diagnostic information, per se., Materials and Methods: A total of 246 patients with acute (<3 weeks) low back pain (LBP) and/or radiculopathy (150 LBP and 96 radiculopathy patients) were recruited. Patients were randomized using a stratified block design with equal allocation to either the unblinded group (MR imaging results provided within 48 hours) or the blinded group (both patient and physician blinded to MR imaging results.) After the initial MR imaging, patients followed 6 weeks of conservative management. Roland function, visual pain analog, absenteeism, Short Form (SF)-36 Health Status Survey, self-efficacy scores, and Fear Avoidance Questionnaire were completed at presentation; 2, 4, 6, and 8 weeks; and 6, 12, and 24 months. Improvement of Roland score by 50% or more and patient satisfaction assessed by Cherkin symptom satisfaction measure were considered a positive outcome., Results: Clinical outcome at 6 weeks was similar for unblinded and blinded patients. Self-efficacy, fear avoidance beliefs, and the SF-36 subscales were similar over time for blinded and unblinded patients, except for the general health subscale on the SF-36. General health of the blinded group improved more than for the unblinded group (P = .008)., Conclusions: Patient knowledge of imaging findings do not alter outcome and are associated with a lesser sense of well-being.

Background: Misclassification of study endpoints in randomized clinical trials of screening tests has been well documented, yet its effect on study power, type I error rate, and risk ratio estimate have not been studied in depth., Methods: We constructed a Markov model to depict the natural history of disease and the effect of screening on it. Using this model we simulated subjects in a two-arm RCT. We varied the type and amount of misclassification, and studied the effect on two endpoints--disease-specific mortality and the incidence of disease-specific symptoms., Results: Failure to identify disease-specific events in a RCT of screening has a small effect on the risk ratio estimate and study power. In contrast, the false identification of events as being attributable to the target disease greatly reduces study power., Conclusions: Investigators of RCTs of screening tests should carefully consider the potential for misclassification and the type of misclassification that their study is as risk for. Studies should be designed to minimize misclassification. The effect of misclassification on power should be considered in sample size calculations.

Purpose: To determine whether computer-aided detection (CAD) applied to computed tomographic (CT) colonography can help improve sensitivity of polyp detection by less-experienced radiologist readers, with colonoscopy or consensus used as the reference standard., Materials and Methods: The release of the CT colonographic studies was approved by the individual institutional review boards of each institution. Institutions from the United States were HIPAA compliant. Written informed consent was waived at all institutions. The CT colonographic studies in 30 patients from six institutions were collected; 24 images depicted at least one confirmed polyp 6 mm or larger (39 total polyps) and six depicted no polyps. By using an investigational software package, seven less-experienced readers from two institutions evaluated the CT colonographic images and marked or scored polyps by using a five-point scale before and after CAD. The time needed to interpret the CT colonographic findings without CAD and then to re-evaluate them with CAD was recorded. For each reader, the McNemar test, adjusted for clustered data, was used to compare sensitivities for readers without and with CAD; a Wilcoxon signed-rank test was used to analyze the number of false-positive results per patient., Results: The average sensitivity of the seven readers for polyp detection was significantly improved with CAD-from 0.810 to 0.908 (P=.0152). The number of false-positive results per patient without and with CAD increased from 0.70 to 0.96 (95% confidence interval for the increase: -0.39, 0.91). The mean total time for the readings was 17 minutes 54 seconds; for interpretation of CT colonographic findings alone, the mean time was 14 minutes 16 seconds; and for review of CAD findings, the mean time was 3 minutes 38 seconds., Conclusion: Results of this feasibility study suggest that CAD for CT colonography significantly improves per-polyp detection for less-experienced readers., (Copyright (c) RSNA, 2007.)

Purpose: The authors performed a pilot randomized controlled trial of total-body screening to assess the feasibility of a full-scale study., Materials and Methods: After informed consent, 50 asymptomatic people were randomized to either the intervention arm (total-body screening with multidetector computed tomography) or the control arm (no screening for 3 years). The study was approved by our institutional review board and was compliant with the Health Insurance Portability and Accountability Act. Images were interpreted independently by 6 radiologists from 2 institutions. Subjects in both study arms completed periodic health questionnaires and medical utilization forms over 2 years. Key outcome variables were the incidence of symptomatic disease, medical costs, and patient-reported health., Results: Sixteen screened subjects (64%) had abnormal findings on screening. A second interpretation of the images yielded a similar overall rate but with considerable variability at the subject level. No cancers were detected. Ninety percent of subjects were compliant at 2 years. Medical costs were twice as high for screened subjects, with considerable between-subject variability. Screened subjects reported fewer physical limitations than unscreened subjects., Conclusion: A full-scale randomized controlled trial of total-body screening will need to account for the large interreader variability in interpreting the images, the high rate of incidental findings, and the low prevalence of cancers. A full-scale study using mortality as the endpoint does not seem feasible at this time.