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Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies, with a dismal survival rate. Screening the general population for early detection of PDAC is not recommended, but because early detection improves survival, high-risk individuals, defined as those meeting criteria based on a family history of PDAC and/or the presence of known pathogenic germline variant genes with PDAC risk, are recommended to undergo screening with MRI and/or endoscopic ultrasound at regular intervals. The Pancreatic Cancer Early Detection (PRECEDE) Consortium was formed in 2018 and is composed of gastroenterologists, geneticists, pancreatic surgeons, radiologists, statisticians, and researchers from 40 sites in North America, Europe, and Asia. The overarching goal of the PRECEDE Consortium is to facilitate earlier diagnosis of PDAC for high-risk individuals to increase survival of the disease. A standardized MRI protocol and reporting template are needed to enhance the quality of screening examinations, improve consistency of clinical management, and facilitate multiinstitutional research. We present a consensus statement to standardize MRI screening and reporting for individuals with elevated risk of pancreatic cancer.

OBJECTIVE The aim of this study was to determine accuracy of height and weight prediction by a 3-dimensional (3D) camera. METHODS A total of 453 patients whose computed tomography imaging used a 3D camera from December 19, 2018 to March 19, 2019 were retrospectively identified. An image of each patient was taken before the computed tomography by a 3D camera mounted to the ceiling. Using infrared imaging and machine learning algorithms, patient height and weight were estimated from this 3D camera image. A total of 363 images were used for training. The test set consisted of 90 images. The height and weight estimates were compared with true height and weight to determine absolute and percent error. A value of P < 0.05 indicated statistical significance. RESULTS There was 2.0% (SD, 1.4) error in height estimation by the 3D camera, corresponding to 3.35 cm (SD, 2.39) absolute deviation (P = 1, n = 86). Weight estimation error was 5.1% (SD, 4.3), corresponding to 3.99 kg (SD, 3.11) absolute error (P = 0.74, n = 90). CONCLUSION Pictures obtained from a 3D camera can accurately predict patient height and weight.

For more than half of Crohn’s disease patients, strictures will cause bowel obstructions that require surgery within 10 years of their initial diagnosis. This study utilizes computed tomography imaging and clinical data obtained at the initial emergency room visit to create a prediction model for progression to surgery in Crohn’s disease patients with acute small bowel obstructions. A retrospective chart review was performed for patients who presented to the emergency room with an ICD-10 diagnosis for Crohn’s disease and visit diagnosis of small bowel obstruction. Two expert abdominal radiologists evaluated the CT scans for bowel wall thickness, maximal and minimal luminal diameters, length of diseased segment, passage of oral contrast, evidence of penetrating disease, bowel wall hyperenhancement or stratification, presence of a comb sign, fat hypertrophy, and small bowel feces sign. The primary outcome was progression to surgery within 6 months of presentation. The secondary outcome was time to readmission. Forty patients met the inclusion criteria, with 78% receiving medical treatment alone and 22% undergoing surgery within 6 months of presentation to the emergency room. Multivariable analysis produced a model with an AUC of 92% (95% CI 0.82–1.00), 78% sensitivity, and 97% specificity, using gender, body mass index, and the radiographic features of segment length, penetrating disease, and bowel wall hyperenhancement. The model demonstrates that routine clinical and radiographic data from an emergency room visit can predict progression to surgery, and has the potential to risk stratify patients, guide management in the acute setting, and predict readmission.

OBJECTIVE The objective of this study was to assess if bowel wall iodine density obtained from dual-source, dual-energy computed tomography enterography (DECTE) could be a biomarker of Crohn's disease activity. METHODS Twenty-two patients with Crohn's disease imaged with DECTE from February 2016 to May 2018 were retrospectively identified by departmental report search. Iodine maps were created with commercial software (Syngovia). Iodine content was normalized to the aorta, and then manual dual-energy region-of-interest cursors were placed over the visibly assessed maximal and minimal iodine density within segments of involved as well as unaffected small bowel. The mixed Hounsfield unit value, maximum iodine density (Imax), and minimum iodine density (Imin) were recorded. The length of affected bowel demonstrating maximum disease activity as a percentage of overall involvement was subjectively assessed. A weighted iodine density (Iweighted) was calculated. The clinical assessment of disease activity using erythrocyte sedimentation rate, C-reactive protein, fecal calprotectin, colonoscopy/endoscopy, and surgery, if available, served as the reference standard. The Crohn's disease activity index was also used as a separate additional reference standard. RESULTS Significant heterogeneity within the affected segments was present. The average Imax and Imin of affected bowel was 4.27 ± 1.11 (2.4-7.4) mg/mL and 2.71 ± 0.51 (2.2-3.9) mg/mL, respectively. Iodine density of normal-appearing small bowel was 1.40 ± 0.26 (0.9-1.9) mg/mL. The Imax and Imin of affected bowel differed significantly from normal bowel (P < 0.0001). Mixed Hounsfield unit (101.82 ± 27.5) also statistically differed (46.33 ± 19.62) (P < 0.0001). Using overall clinical assessment as the reference standard, all patients with Imin of greater than 2.6 mg/mL, Iweighted of greater than 3.3 mg/mL, or Imax of greater than 4.7 mg/mL had clinically active disease. Sixteen of 17 patients with Imin of greater than 2.2 mg/mL and 14/15 with Iweighted of greater than 3 mg/mL had clinically active disease. Using Crohn's disease activity index as the reference standard, all patients with Imin of greater than 2.7 mg/mL, Iweighted of greater than 3.6 mg/mL, or Imax of greater than 5.4 mg/mL had clinically active disease. The median effective dose was 4.64 ± 1.68 mSv (range, 2.03-8.12 mSv). CONCLUSIONS Iodine density obtained from DECTE highlights regions of maximal activity within affected bowel segments. An iodine density of 2 mg/mL appears to be a threshold between normal bowel segments and those with active Crohn's disease. Iodine density measurement thresholds Imin of greater than 2.6 mg/mL, Iweighted of greater than 3.3 mg/mL, and Imax of greater than 4.7 mg/mL correlate with established clinical markers of disease activity, with Imin seemingly most useful in daily clinical practice.

Dual-energy CT (DECT) has been available for clinical use in the United States for close to 15 years. Although multiple applications in all areas of the body have been described that are only possible with DECT, the adoption into clinical practice has been slow. This paper will attempt to address many of the impediments the author has encountered from his discussions with radiologists across the country. A hopeful outcome would result in more practices adopting more DECT into their CT practices.

The lack of prospective outcomes studies for many types of incidental findings limits our understanding of both their natural history and the potential efficacy of treatment. To support decision making for the management of incidental findings, major sources of uncertainty in management pathways can be mapped and analyzed using mathematical models. This process yields important insights into how uncertainty influences the best treatment decision. Here, we consider a classification scheme, grounded in decision science, which exposes various levels and types of uncertainty in the management of incidental findings and addresses (1) disease-related risks, which are considered in context of a patient's competing causes of mortality; (2) potential degrees of intervention; (3) strength of evidence; and (4) patients' treatment-related preferences. Herein we describe how categorizing uncertainty by the sources, issues, and locus can build a framework from which to improve the management of incidental findings. Accurate and comprehensive handling of uncertainty will improve the quality of related decision making and will help guide future research priorities.

To assess current practice patterns with respect to protocols used for incidental pancreatic cyst follow-up, management guidelines, and template reporting.The Society of Abdominal Radiology Disease Focused Panel on intraductal pancreatic neoplasms distributed an anonymous 14-question survey to its members in June 2018 that focused on current utilization of incidental pancreatic cyst guidelines, protocols, and template reporting.Among the 1,390 email invitations, 323 responded, and 94.7% (306 of 323) completed all questions. Respondents were mainly radiologists (93.8%, 303 of 323) from academic institutions (74.7%, 227 of 304) in North America (93.7%, 286 of 305). Of respondents, 42.5% (136 of 320) preferred 2017 ACR recommendations, 17.8% (57 of 320) homegrown systems, 15.0% (48 of 320) Fukuoka guidelines, and 7.8% (25 of 320) American Gastroenterological Association guidelines. The majority (68.7%, 222 of 323) agreed or strongly agreed that developing a single international consensus recommendation for management was important, and most radiologists preferred to include them in reports (231 of 322, 71.7%); yet only half included recommendations in75% of reports (161 of 321). MR cholangiopancreatography was the modality of choice for follow-up of2.5 cm cysts. Intravenous contrast was routinely used by 69.7% (212 of 304). Standardized reporting templates were rarely used in practice (12.8% 39 of 306).Nearly 7 of 10 radiologists desire a unified international consensus recommendation for management of incidental cystic pancreatic lesions; ACR 2017 recommendations are most commonly used, followed by homegrown systems and Fukuoka guidelines. The majority of radiologists routinely use MR cholangiopancreatography with intravenous contrast for follow-up of incidental cystic lesions, but template reporting is rarely used.

Ileal pouch-anal anastomosis (IPAA) surgery is the reference standard surgical procedure for treatment of ulcerative colitis and most patients with familial adenomatous polyposis. This procedure allows preservation of fecal continence and gastrointestinal continuity. However, it is associated with a wide variety of complications, which often have nonspecific and overlapping clinical presentations, making imaging an important part of workup for pouch dysfunction. The purpose of this article is to propose structured reporting templates for MRI and water-soluble contrast enema (WSCE), based on our referral pouch center's experience, in patients who have undergone IPAA surgery. We review salient surgical technique, pouch anatomy, and imaging protocols, with an emphasis on a systematic search pattern for evaluation of ileal pouch complications using proposed structured reporting templates for MRI and WSCE.

OBJECTIVE To create a map of iodine densities within affected segments of small-bowel Crohn disease (CD) derived from contrast-enhanced dual-energy computed tomography enterography (DECTE) studies. METHODS Twenty CD patients imaged with intravenous contrast-enhanced DECTE between June 2016 and December 2017 were retrospectively identified. Ten patients without clinical evidence of CD and 8 normal-appearing jejunal segments in CD patients were controls. Using prototype software, 8 manual contours were drawn along the mucosa of affected segments. Relatively normal-appearing bowel was included at the edges. These contours served as a basis for iodine density calculation and 3-dimensional iodine density map rendering. Color-coded iodine densities allowed detection and quantification of the most and least dense portion of each segment and also permitted relative comparison between segments. RESULTS The average iodine density per CD involved segment ranged 1.0 to 3.3 mg/mL, which differed significantly from normal ileum (P < 0.0001) and normal-appearing jejunum in patients with CD (P = 0.0009). Standard deviations ranged from 0.8 to 1.7 mg/mL, which differed significantly from normal ileum (P = 0.0039) and normal-appearing jejunum in patients with CD (P = 0.0056). The amplitude of the power spectrum ranged from 0.66 to 3.3 demonstrating patches of iodine rather than uniform distribution. This differed significantly from normal ileum (P = 0.0005) and normal-appearing jejunum in patients with CD (P = 0.0004). CONCLUSIONS Heterogeneous CD activity and distribution can be displayed as iodine density maps created from DECTE.

The objective of this study is to evaluate whether the water siphon maneuver improves detection of gastroesophageal (GE) reflux during barium esophagography compared with observation for spontaneous reflux only. Histopathologic analysis is the reference standard.This retrospective study assessed 87 outpatients who underwent both barium esophagography and upper endoscopy-guided biopsy within a 30-day interval. The water siphon maneuver was routinely performed when spontaneous GE reflux was not observed during the fluoroscopic study. Radiology reports were reviewed for mentions of the presence of reflux and the circumstances in which it was observed (as a spontaneous occurrence or as a result of the water siphon maneuver). Pathology reports from subsequent endoscopic biopsies were reviewed to identify histologic changes of reflux disease. The sensitivity, specificity, and accuracy of esophagography, observation for spontaneous reflux, and the water siphon maneuver were calculated and then compared using a McNemar test.Of the 87 patients, 57 (65.5%) had GE reflux diagnosed on the basis of histologic changes noted on endoscopy, and 30 (34.5%) did not. A total of 57 patients (65.5%) showed reflux during esophagography, 41 (71.9%) of whom had reflux diagnosed by the water siphon maneuver, and 16 (28.1%) had reflux diagnosed on the basis of observation of spontaneous reflux. Forty-four patients had reflux diagnosed on the basis of both a barium study and histologic findings; 13 patients had reflux noted on esophagography but had negative histologic findings. The overall sensitivity, specificity, and accuracy of esophagography for reflux were 77.2%, 56.7%, and 70.1%, respectively. Spontaneous reflux alone had a sensitivity, specificity, and accuracy of 21.1%, 86.7%, and 43.7%, respectively. The water siphon maneuver showed a sensitivity of 71.1%, a specificity of 65.4%, and accuracy of 69.0%. The differences in the sensitivity, specificity, and accuracy of the water siphon maneuver versus observation of spontaneous reflux were statistically significant (p ≤ 0.004).A properly performed and interpreted water siphon maneuver significantly increases the sensitivity and accuracy for GE reflux during esophagography, compared with observation for spontaneous reflux alone. The water siphon maneuver is a simple addition to barium esophagography that improves sensitivity and accuracy for the diagnosis of GE reflux compared with observation alone.

Computed tomography and magnetic resonance enterography have become routine small bowel imaging tests to evaluate patients with established or suspected Crohn's disease, but the interpretation and use of these imaging modalities can vary widely. A shared understanding of imaging findings, nomenclature, and utilization will improve the utility of these imaging techniques to guide treatment options, as well as assess for treatment response and complications. Representatives from the Society of Abdominal Radiology Crohn's Disease-Focused Panel, the Society of Pediatric Radiology, the American Gastroenterological Association, and other experts, systematically evaluated evidence for imaging findings associated with small bowel Crohn's disease enteric inflammation and established recommendations for the evaluation, interpretation, and use of computed tomography and magnetic resonance enterography in small bowel Crohn's disease. This work makes recommendations for imaging findings that indicate small bowel Crohn's disease, how inflammatory small bowel Crohn's disease and its complications should be described, elucidates potential extra-enteric findings that may be seen at imaging, and recommends that cross-sectional enterography should be performed at diagnosis of Crohn's disease and considered for small bowel Crohn's disease monitoring paradigms. A useful morphologic construct describing how imaging findings evolve with disease progression and response is described, and standard impressions for radiologic reports that convey meaningful information to gastroenterologists and surgeons are presented.

OBJECTIVE. The objective of our study was to test for the possibility that published malignancy risks for side-branch intraductal papillary mucinous neoplasms (IPMNs) are overestimates, likely due to verification bias. MATERIALS AND METHODS. We tested for possible verification bias using simulation modeling techniques. First, in age-defined hypothetical cohorts of 10 million persons, we projected the frequency of pancreatic ductal adenocarcinoma (PDAC) arising from side-branch IPMNs over 5 years using published estimates of their prevalence (4.4%) and rate of malignant transformation (1.9%). Second, we projected the total number of PDAC cases in corresponding cohorts over the same time horizon using national cancer registry data. For each cohort, we determined whether the percentage of all PDAC cases that arose from side-branch IPMNs (i.e., side-branch IPMN–associated PDAC cases) was clinically plausible using an upper limit of 10% to define plausibility, as estimated from the literature. Model assumptions and parameter uncertainty were evaluated in sensitivity analysis. RESULTS. Across all cohorts, percentages of side-branch IPMN–associated PDACs greatly exceeded 10%. In the base case (mean age = 55.7 years), 80% of PDAC cases arose from side-branch IPMNs (7877/9786). In the oldest cohort evaluated (mean age = 75 years), this estimate was 76% (14,227/18,714). In a secondary analysis, we found that if an upper limit threshold of 10% for side-branch IPMN–associated PDAC was imposed, the model-predicted rate of malignancy for side-branch IPMNs would be less than 0.24% over a 5-year time horizon, substantially lower than most literature-based estimates. CONCLUSION. Our results suggest that reported malignancy risks associated with side-branch IPMNs are likely to be overestimates and imply the presence of verification bias.

To compare CT isocenter accuracy, patient dose, and scan time in adults imaged with and without use of a 3D camera.571 CT examinations utilizing a 3D camera for initial patient positioning (optional radiographer isocenter adjustment) and 504 examinations scanned without the camera between 10/1/2018 and 3/19/2019 were retrospectively identified. All exams were chest or abdominopelvic CTs. The isocenters of these exams were compared with the true isocenters defined as the manually delineated centroid of the body in the CT volume. The size specific dose estimate (SSDE) (mGy) of radiation dose obtained from departmental software for the 4 most common protocols on one CT scanner was compared before and after implementation of the 3D camera. The times required for the entire scan and just the topogram "scout" were compared with and without the 3D camera for noncontrast chest and abdominopelvic CT enterography protocols. 2-tailed t-tests and Mann-Whitney U tests were used (P 0.05 indicated statistical significance).The deviation from true isocenter was 6.8 ± 6.1 mm (P = 0.043) and 16.3 ± 14.0 mm (P 0.01) with and without the 3D camera, respectively (P 0.01). CT radiographers accepted isocenter location without alteration in 93 % of examinations. Average SSDE savings with the 3D camera ranged 1.0-2.4 mGy (21-31 %) for the 4 most commonly performed protocols (p 0.01). Median scout time savings was 32 s (Camera vs. No-Camera cohorts) (P 0.01). Average noncontrast chest CT and CT enterography scan time savings were 19 s and 17 s with the 3D camera, respectively (P 0.01).The 3D camera improved accuracy of patient positioning while reducing radiation dose and examination time. Implementation of a 3D camera helps standardize workflow in a busy clinical practice.

Dual energy computed tomography has been available for more than 10 years; however, it is currently on the cusp of widespread clinical use. The way dual energy data are acquired and assembled must be appreciated at the clinical level so that the various reconstruction types can extend its diagnostic power. The type of scanner that is present in a given practice dictates the way in which the dual energy data can be presented and used. This article compares and contrasts how dual source, rapid kV switching, and spectral technologies acquire and present dual energy reconstructions to practicing radiologists.

Purpose To determine the effects of patient age and comorbidity level on life expectancy (LE) benefits associated with imaging follow-up of Bosniak IIF renal cysts and pancreatic side-branch (SB) intraductal papillary mucinous neoplasms (IPMNs). Materials and Methods A decision-analytic Markov model to evaluate LE benefits was developed. Hypothetical cohorts with varied age (60-80 years) and comorbidities (none, mild, moderate, or severe) were evaluated. For each finding, LE projections from two strategies were compared: imaging follow-up and no imaging follow-up. Under follow-up, it was assumed that cancers associated with the incidental finding were successfully treated before they spread. For patients without follow-up, mortality risks from Bosniak IIF cysts (renal cell carcinoma) and SBIPMNs (pancreatic ductal adenocarcinoma) were incorporated. Model assumptions and parameter uncertainty were evaluated in sensitivity analysis. Results In the youngest, healthiest cohorts (age, 60 years; no comorbidities), projected LE benefits from follow-up were as follows: Bosniak IIF cyst, 6.5 months (women) and 5.8 months (men); SBIPMN, 6.4 months (women) and 5.3 months (men). Follow-up of Bosniak IIF cysts in 60-year-old women with severe comorbidities yielded a LE benefit of 3.9 months; in 80-year-old women with no comorbidities, the benefit was 2.8 months, and with severe comorbidities the benefit was 1.5 months. Similar trends were observed in men and for SBIPMN. Results were sensitive to the performance of follow-up for cancer detection; malignancy risks; and stage at presentation of malignant, unfollowed Bosniak IIF cysts. Conclusion With progression of age and comorbidity level, follow-up of low-risk incidental findings yields increasingly limited benefits for patients. © RSNA, 2018 Online supplemental material is available for this article.

Chronic pancreatitis is an inflammatory condition of the pancreas with clinical manifestations ranging from abdominal pain, acute pancreatitis, exocrine and/or endocrine dysfunction, and pancreatic cancer. There is a need for longitudinal studies in well-phenotyped patients to ascertain the utility of cross-sectional imaging findings of chronic pancreatitis for diagnosis and assessment of disease severity. CT and MR cholangiopancreatography are the most common cross-sectional imaging studies performed for the evaluation of chronic pancreatitis. Currently, there are no universal reporting standards for chronic pancreatitis. Several features of chronic pancreatitis are applied clinically, such as calcifications, parenchymal T1 signal changes, focal or diffuse gland atrophy, or irregular contour of the gland. Such findings have not been incorporated into standardized diagnostic criteria. There is also lack of consensus on quantification of disease severity in chronic pancreatitis, other than by using ductal features alone as described in the Cambridge classification. The Consortium for the Study of Chronic Pancreatitis, Diabetes, and Pancreatic Cancer (CPDPC) was established by the National Institute of Diabetes and Digestive and Kidney Diseases and the National Cancer Institute in 2015 to undertake collaborative studies on chronic pancreatitis, diabetes mellitus, and pancreatic adenocarcinoma. CPDPC investigators from the Adult Chronic Pancreatitis Working Group were tasked with development of a new consensus approach to reporting features of chronic pancreatitis aimed to standardize diagnosis and assessment of disease severity for clinical trials. This consensus statement presents and defines features of chronic pancreatitis along with recommended reporting metrics. © RSNA, 2018 Online supplemental material is available for this article. See also the editorial by Megibow in this issue.

The purpose of this study is to assess differences in patient distress, risk perception, and treatment preferences for incidental renal findings with descriptive versus combined descriptive and numeric graphical risk information.A randomized survey study was conducted for adult patients about to undergo outpatient imaging studies at a large urban academic institution. Two survey arms contained either descriptive or a combination of descriptive and numeric graphical risk information about three hypothetical incidental renal findings at CT: 2-cm (low risk) and 5-cm (high risk) renal tumors and a 2-cm (low risk) renal artery aneurysm. The main outcomes were patient distress, perceived risk (qualitative and quantitative), treatment preference, and valuation of lesion discovery.Of 374 patients, 299 participated (79.9% response rate). With inclusion of numeric and graphical, rather than only descriptive, risk information about disease progression for a 2-cm renal tumor, patients reported less worry (3.56 vs 4.12 on a 5-point scale; p0.001) and favored surgical consultation less often (29.3% vs 46.9%; p = 0.003). The proportion choosing surgical consultation for the 2-cm renal tumor decreased to a similar level as for the renal artery aneurysm with numeric risk information (29.3% [95% CI, 21.7-36.8%] and 27.9% [95% CI, 20.5-35.3%], respectively). Patients overestimated the absolute risk of adverse events regardless of risk information type, but significantly more so when given descriptive information only, and valued the discovery of lesions regardless of risk information type (range, 4.41-4.81 on a 5-point scale).Numeric graphical risk communication for patients about incidental renal lesions may facilitate accurate risk comprehension and support patients in informed decision making.

Pancreatic ductal adenocarcinoma is an aggressive malignancy with a high mortality rate. Proper determination of the extent of disease on imaging studies at the time of staging is one of the most important steps in optimal patient management. Given the variability in expertise and definition of disease extent among different practitioners as well as frequent lack of complete reporting of pertinent imaging findings at radiologic examinations, adoption of a standardized template for radiology reporting, using universally accepted and agreed on terminology for solid pancreatic neoplasms, is needed. A consensus statement describing a standardized reporting template authored by a multi-institutional group of experts in pancreatic ductal adenocarcinoma that included radiologists, gastroenterologists, and hepatopancreatobiliary surgeons was developed under the joint sponsorship of the Society of Abdominal Radiologists and the American Pancreatic Association. Adoption of this standardized imaging reporting template should improve the decision-making process for the management of patients with pancreatic ductal adenocarcinoma by providing a complete, pertinent, and accurate reporting of disease staging to optimize treatment recommendations that can be offered to the patient. Standardization can also help to facilitate research and clinical trial design by using appropriate and consistent staging by means of resectability status, thus allowing for comparison of results among different institutions.

OBJECTIVE The purpose of this study is to review multidetector computed tomography (CT) imaging findings of mesenteric venous thrombosis occurring following bariatric surgery. To our knowledge, this complication has not been described in the radiologic literature. METHODS Multidetector CT examinations of 6 patients known to have developed mesenteric venous thrombosis after laparoscopic bariatric surgery were reviewed. The thrombus was characterized, and associated imaging findings including presence of mesenteric edema, small bowel edema, and thrombotic complications were described. RESULTS Four patients underwent laparoscopic sleeve gastrectomy approximately 12 days before CT diagnosis of mesenteric thrombosis and 2 patients had a laparoscopic Roux-en-Y gastric bypass approximately 11 years before imaging diagnosis of mesenteric thrombosis.The thrombus occupied the entire length of the superior mesenteric vein in all cases. Extension into jejunal branches was present in 4 cases. The thrombus was completely occlusive in 4 of 6 patients. CONCLUSIONS Mesenteric venous thrombosis is an increasingly recognized complication of laparoscopic bariatric surgery. Awareness demands that postbariatric surgery patients with acute abdominal pain be studied with intravenous contrast material.

Multi-detector computed tomography (MDCT) enables volumetric scans in a single breath hold and is clinically useful for hepatic imaging. For simple tasks, conventional single energy (SE) computed tomography (CT) images acquired at the optimal tube potential are known to have better quality than dual energy (DE) blended images. However, liver imaging is complex and often requires imaging of both structures containing iodinated contrast media, where atomic number differences are the primary contrast mechanism, and other structures, where density differences are the primary contrast mechanism. Hence it is conceivable that the broad spectrum used in a dual energy acquisition may be an advantage. In this work we are interested in comparing these two imaging strategies at equal-dose and more complex settings.We developed numerical anthropomorphic phantoms to mimic realistic clinical CT scans for medium size and large size patients. MDCT images based on the defined phantoms were simulated using various SE and DE protocols at pre- and post-contrast stages. For SE CT, images from 60 kVp through 140 with 10 kVp steps were considered; for DE CT, both 80/140 and 100/140 kVp scans were simulated and linearly blended at the optimal weights. To make a fair comparison, the mAs of each scan was adjusted to match the reference radiation dose (120 kVp, 200 mAs for medium size patients and 140 kVp, 400 mAs for large size patients). Contrast-to-noise ratio (CNR) of liver against other soft tissues was used to evaluate and compare the SE and DE protocols, and multiple pre- and post-contrasted liver-tissue pairs were used to define a composite CNR. To help validate the simulation results, we conducted a small clinical study. Eighty-five 120 kVp images and 81 blended 80/140 kVp images were collected and compared through both quantitative image quality analysis and an observer study.In the simulation study, we found that the CNR of pre-contrast SE image mostly increased with increasing kVp while for post-contrast imaging 90 kVp or lower yielded higher CNR images, depending on the differential iodine concentration of each tissue. Similar trends were seen in DE blended CNR and those from SE protocols. In the presence of differential iodine concentration (i.e., post-contrast), the CNR curves maximize at lower kVps (80-120), with the peak shifted rightward for larger patients. The combined pre- and post-contrast composite CNR study demonstrated that an optimal SE protocol has better performance than blended DE images, and the optimal tube potential for SE scan is around 90 kVp for a medium size patients and between 90 and 120 kVp for large size patients (although low kVp imaging requires high x-ray tube power to avoid photon starvation). Also, a tin filter added to the high kVp beam is not only beneficial for material decomposition but it improves the CNR of the DE blended images as well. The dose adjusted CNR of the clinical images also showed the same trend and radiologists favored the SE scans over blended DE images.Our simulation showed that an optimized SE protocol produces up to 5% higher CNR for a range of clinical tasks. The clinical study also suggested 120 kVp SE scans have better image quality than blended DE images. Hence, blended DE images do not have a fundamental CNR advantage over optimized SE images.

OBJECTIVE. The purpose of this perspective is to document an experience with the adoption of dual-energy CT (DECT) for routine clinical imaging. CONCLUSION. Successful implementation of DECT requires that technologists understand standards of image quality, be empowered to select appropriate patients, and understand networks for image routing. Radiologists need minimal facility with workstations to access the information embedded in DECT. DECT can be performed at a reduced effective radiation dose compared with single-energy CT and with lower doses of IV contrast material.

The vast array of possible histologies for a given pancreatic mass makes the specific diagnosis of a solid pancreatic mass in an individual patient challenging. This article discusses and reviews the imaging findings of those entities that are likely to be encountered in clinical practice, specifically pancreatic endocrine tumors, solid pseudopapillary tumor, secondary pancreatic masses, and heterotopic spleen.

The introduction of dual-energy computed tomography systems (ie, scanners that can simultaneously acquire images at different energies) has significant and unique applications for urologists. Imaging data from these scanners can be used to evaluate composition of urinary calculi and, by "removing" iodine from an image, significantly decrease radiation dose to patients referred for hematuria. Further, the ability to create a virtual noncontrast image obviates the need for repeated scanning in patients with incidentally detected renal and adrenal masses. Finally, the ability to quantify the regional concentration of iodine in a renal neoplasm may provide a method to monitor effectiveness of therapy before size changes become apparent.

Purpose The aim of this study was to evaluate for agreement with respect to how radiologists report incidental findings encountered on CT. Methods A multiple-choice survey was designed to query radiologists about how they handle 12 incidental findings on body CT, assuming the patient is a 45-year-old woman with no history of malignancy. Included were a 1-cm thyroid nodule, a 5-mm noncalcified lung nodule, coronary artery calcification, a 2-cm adrenal nodule, a 2-cm pancreatic cyst, a 1-cm enhancing liver lesion, a 2-cm high-density renal cyst, short-segment small bowel intussusception, a 1-cm splenic cyst, focal gallbladder wall calcification, and a 3-cm ovarian cyst in both a premenopausal woman and a postmenopausal woman. Choices ranged from "do not report" to advising interventional procedures tailored to the organ. Surveys were administered to body CT attending radiologists at 3 academic institutions. Results Twenty-seven radiologists completed the survey. The mean experience level was 15.7 years after training. Seventy percent or greater agreement on interpretation was identified for only 6 findings: recommend ultrasound for a 1-cm thyroid nodule, recommend ultrasound for a 3-cm cyst in postmenopausal woman, follow Fleischner Society recommendations for a 5-mm lung nodule, describe only coronary calcification, and describe as likely benign both short-segment small bowel intussusception and a 1-cm splenic cyst. Conclusions Agreement is lacking, both across institutions and within departments, for the management of 6 commonly encountered incidental findings on body CT. Individual departments should develop internal guidelines to ensure consistent recommendations based on existing evidence.

To retrospectively evaluate the frequency of recommendations for additional imaging (RAIs) for important extracolonic findings and polyp prevalence among a cohort of seniors (age ≥ 65 years) and nonseniors (age65 years) undergoing low-dose computed tomographic (CT) colonography.Institutional review board approval was obtained for this HIPAA-compliant retrospective study. Four hundred fifty-four patients (204 nonseniors: mean age, 52 years; 250 seniors: mean age, 69 years) underwent CT colonography at an outpatient facility. Cases were prospectively reported by one of four abdominal radiologists with expertise in CT colonography. The dictated reports were reviewed to determine the frequency of polyps (≥6 mm), the number of extracolonic findings, and the number of RAIs generated. The Fisher exact test was used to compare the percentage of seniors and nonseniors with at least one reported polyp, with at least one extracolonic finding, as well as the frequency of RAIs.The percentage of patients with at least one reported polyp was 14.2% (29 of 204) for the nonsenior group and 13.2% (33 of 250) for seniors, which was not significantly different (P = .772). The percentage of patients with at least one extracolonic finding was 55.4% (113 of 204) for nonseniors and 74.0% (185 of 250) for seniors (P.0001). The percentage of patients in which an RAI was suggested was 4.4% (nine of 204) for nonseniors and 6.0% (15 of 250) for seniors, which was not significantly different (P = .450).Extracolonic findings were more frequent in seniors than in nonseniors; however, there was no significant difference in the frequency of RAIs between the two groups.http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11102144/-/DC1.

The purpose of this study was to validate the utility of dual-source dual-energy MDCT in quantifying iodine concentration in a phantom and in renal masses.A series of tubes containing solutions of varying iodine concentration were imaged with dual-source dual-energy MDCT. Iodine concentration was calculated and compared with known iodine concentration. Single-phase contrast-enhanced dual-source dual-energy MDCT data on 15 patients with renal lesions then were assessed independently by two readers. Dual-energy postprocessing was used to generate iodine-only images. Regions of interest were placed on the iodine image over the lesion and, as a reference, over the aorta, for recording of iodine concentration in the lesion and in the aorta. Another radiologist determined lesion enhancement by comparing truly unenhanced with contrast-enhanced images. Mixed-model analysis of variance based on ranks was used to compare lesion types (simple cyst, hemorrhagic cyst, enhancing mass) in terms of lesion iodine concentration and lesion-to-aorta iodine ratio.In the phantom study, there was excellent correlation between calculated and true iodine concentration (R(2) = 0.998, p0.0001). In the patient study, 13 nonenhancing (10 simple and three hyperdense cysts) and eight enhancing renal masses were evaluated in 15 patients. The lesion iodine concentration and lesion-to-aorta iodine ratio in enhancing masses were significantly higher than in hyperdense and simple cysts (p0.0001).Iodine quantification with dual-source dual-energy MDCT is accurate in a phantom and can be used to determine the presence and concentration of iodine in a renal lesion. Characterization of renal masses may be possible with a single dual-source dual-energy MDCT acquisition without unenhanced images or reliance on a change in attenuation measurements.

The discovery of a pancreatic cyst in an asymptomatic patient presents an immediate challenge to the interpreting radiologist, the clinician who manages the patient, and patients themselves. When a cyst is discovered on imaging in a patient without symptoms directly referable to the pancreas, the following questions are immediately raised: can the lesion be accurately diagnosed or is the appropriate management clear from the examination, is the best management approach to suggest watchful waiting with follow-up imaging, what is the best method for imaging follow-up, and what is the optimal frequency of follow-up? This article recommends an approach to analyzing patients with incidental pancreatic cysts.

To compare the evaluation times and accuracy of unidirectional panoramic three-dimensional (3D) endoluminal interpretation to traditional two-dimensional (2D) and bidirectional 3D endoluminal techniques.Sixty-nine patients underwent computed tomography colonography (CTC) after bowel cleansing. Forty-five had no polyps and 24 had at least one polypor = 6 mm. Patients underwent same-day colonoscopy with segmental unblinding. Three experienced abdominal radiologists evaluated the data using one of three primary interpretation techniques: (1) 2D; (2) bidirectional 3D; (3) panoramic 3D. Mixed model analysis of variance and logistic regression for correlated data were used to compare techniques with respect to time and sensitivity and specificity.Mean evaluation times were 8.6, 14.6, and 12.1 min, for 2D, 3D, and panoramic, respectively. 2D was faster than either 3D technique (p0.0001), and the panoramic technique was faster than bidirectional 3D (p = 0.0139). The overall sensitivity of each technique per polyp and per patient was 68.4 and 76.7% for 2D, 78.9 and 93.3% for 3D; and 78.9 and 86.7% for panoramic 3D.2D interpretation was the fastest overall, the panoramic technique was significantly faster than the bidirectional with similar sensitivity and specificity. The sensitivity for a single reader was significantly lower using the 2D technique. Each reader should select the technique with which they are most successful.

Cystic pancreatic masses are increasingly recognized as a direct consequence of widespread imaging. Once detected, there is controversy as to further management. This review briefly describes the radiologic appearance of these lesions on computed tomography or magnetic resonance imaging. Recommendations for management based on the imaging findings are discussed.

OBJECTIVE. Imaging of the vast array of pathologic processes occurring in the small bowel has been facilitated by recent advances, including the use of MDCT scanners that acquire isotropic data and neutral oral contrast agents that improve small-bowel distention.CONCLUSION. This review shows how a systematic pattern approach can be used to narrow the differential diagnosis when an abnormal small-bowel loop is detected on MDCT.

OBJECTIVE. Stercoral colitis is an inflammatory process involving the colonic wall related to fecal impaction. Our purpose was to describe the imaging findings of stercoral colitis and ulceration and to emphasize the potential serious clinical implications of the condition.CONCLUSION. Fecal impaction may lead to ischemic pressure necrosis and subsequent colonic perforation. In the appropriate clinical setting, the imaging findings that should prompt the radiologist to consider this diagnosis are the presence of fecal impaction, focal colonic wall thickening, and adjacent stranding of the fat. If the fecal impaction is not promptly relieved, the condition can lead to colonic perforation, peritonitis, and patient demise.

Using receiver-operating characteristic (ROC) methodology, the ability to diagnose acute appendicitis with computed tomography (CT) images displayed at varying levels of lossy compression was evaluated. Nine sequential images over the ileocecal region were obtained from 53 consecutive patients with right lower quadrant pain who were clinically suspected to have acute appendicitis. Thirty were proven surgically to have acute appendicitis, alternative diagnoses confirmed in 23. The image sets were subjected to a lossy wavelet-based compression algorithm "Embedded Predictive Wavelet Image Coder" (EPWIC). Compression levels were: none, 8:1, 16:1, and 24:1, resulting in 4 sets of images per patient. Image sets were randomized and evaluated separately by 4 body radiologists on a 1,024 × 768-pixel SVGA color PC monitor in 512 × 512 format. The readers were aware of the clinical suspicion of appendicitis but were unaware of the positive fraction of cases. Individual and combined reader ROC and c2 analyses of sensitivity, specificity, and accuracy were determined. For all readers, sensitivity decreases at 16:1 and 24:1 levels (P

From its inception, CT was welcomed into the clinical arena because of its expansion of the contrast scale and quantitative capabilities embodied in the Hounsfield unit; the Marin et al and Mileto et al articles published this month in Radiology show how developments in technology can advance this remarkable imaging modality even further by increasing its precision.

To perform qualitative and quantitative comparison of images in same patients undergoing CT enterography (CTE) with 100 kVp iterative reconstruction and 120 kVp filtered back projection. In this retrospective study, 50 consecutive patients who underwent imaging with 100 kVp and iterative reconstruction (100-IR) and had prior imaging with 120 kVp filtered back projection (120-FBP) were included. Subjective image quality parameters were evaluated by two independent and blinded readers, with higher score implying better image quality. We developed a quantitative measure of image sharpness by measuring edge-width of the psoas-fat interface. Image noise was measured as a standard deviation of attenuation measurement in the homogeneous region of the subcutaneous fat. Image sharpness and noise were measured and compared between 100-IR and 120-FBP acquisitions. There was approximately 33% lower radiation dose as estimated by CTDIvol with 100-IR compared to 120-FBP (9.95 vs. 15.0; p

Background: We retrospectively reviewed the imaging features of a series of patients with cystic pancreatic masses, the majority of whom underwent imaging surveillance. Methods: Imaging data from 30 patients with known cystic pancreatic masses were reviewed. Nine patients had surgical and/or cytologic classification. Of the 21 who were not operated on, all underwent serial imaging surveillance. Of these, five had corroborative endoscopic retrograde cholangiopancreatography and 16 were followed by only computed tomography and/or magnetic resonance imaging. Results: In the nonoperated group, mean follow-up time was 30 months (3–144 months). Two patients demonstrated growth, and the remainder remain stable. In the patients who underwent surgery, invasive carcinoma was found in those with lesions larger than 4 cm, involvement of the main pancreatic duct, or visible solid components on the imaging study. Smaller lesions were benign. Conclusion: In patients with suspected cystic pancreatic neoplasms, surveillance might be possible if lesions are smaller than 2.5 cm, spare the main pancreatic duct, and demonstrate no solid components.

In 70 patients referred for evaluation of aortoiliac aneurysm disease, multi-detector row computed tomography was performed with a uniform 25-second delay from the initiation of intravenous administration of a 150-mL bolus of contrast material at 4 mL/sec. In all patients, adequate enhancement (>200 HU) of the aorta and intense enhancement of iliofemoral runoff was achieved without venous contamination.

Current MR imaging technology offers the surgeon diagnostic information about pancreatic diseases. This article reviews the basics of MR imaging formation and the rationale for the different types of imaging sequences that comprise a comprehensive pancreaticobiliary examination. Clinical examples include evaluation of pancreatic neoplasms, acute and chronic pancreatitis, and congenital abnormalities.

The purpose of our study was to determine the minimum optimal dose of IV contrast medium for helical CT that can preserve image quality while reducing cost.Four hundred sixty-three patients from six centers were enrolled in a prospective trial in which patients were randomized into one of four weight-based dose categories of iopromide, 300 mg I/mL: 1.25, 1.50, 1.75, and 2.0 mL/kg. Six of 463 patients were excluded from analysis. A radiologist at each center who was unaware of the volume of contrast medium administered determined whether the scans were acceptable. The responses were analyzed by dose, in aggregate, and by weight. Enhancement values (in Hounsfield units) in regions of interest in the liver, pancreas, aorta, and kidneys were obtained at a single time during the scan. The participating radiologist was unaware of these values. Finally, three additional nonparticipating site observers assessed the images for acceptability, diagnostic quality, and overall level of confidence. A cost model comparing incurred charges in using 150 or 100 mL, or 1.5 mL/kg, of low osmolality contrast medium was developed from experience in an additional 303 patients.We found no clinically significant difference in acceptability of scans at doses greater than 1.5 mL/kg. However, significant variability occurred among the centers. The use of 1.5 mL/kg led to a savings of $9927.16 for 303 patients when compared with the use of 150 mL at list price. The cost is the same for 1.5 mL/kg or use of 100 mL of contrast medium.A weight-based dose at 1.5 mL/kg of low osmolality contrast medium can provide acceptable scans in most patients, with a significant cost savings.

137 T colonography is an imaging technique that enables both two-dimensional (2D) and three-dimensional (3D) evaluation of the colon [1–3]. Although debate continues regarding which rendering technique should be used for primary evaluation, the techniques (2D and 3D) are complementary, each increasing the value of CT for colonic lumen evaluation. Two-dimensional CT colonography, when used as the primary imaging technique, may be advantageous in that data may be evaluated in a more time-efficient fashion [2, 3]. When a potential filling defect is identified on 2D CT colonography, 3D imaging is used to determine whether its morphology is linear (interhaustral fold) or polypoid (stool or polyp) [2, 3]. Three-dimensional CT colonography has the potential to visualize smaller lesions than 2D CT colonography [4]. Although some additional small lesions may be identified, evaluating CT colonography data entirely with 3D imaging is time-consuming. Moreover, often lesions are detected using 3D CT colonography that show morphology consistent with a polyp or neoplasm. When these same areas are investigated with 2D CT colonography, a variety of normal structures may be found to represent these morphologic abnormalities. Whether one uses 2D or 3D as the primary rendering method, the pitfalls on 3D imaging need to be recognized. Three-dimensional morphologic abnormalities can be divided into processes that are intrinsic or extrinsic to the colon. Our purpose is to describe the normal colon with 3D CT colonography and to show how 2D imaging can be used to establish the cause of an abnormality depicted with 3D rendering.

OBJECTIVE: Our objective was to investigate the use of CT colonography in patients who have undergone incomplete colonoscopy. CONCLUSION: CT colonography is effective in evaluating portions of the colon not seen during colonoscopy and may have an adjunctive role.

To evaluate routine non-contrast material-enhanced helical computed tomography (CT) of the adrenal glands in patients with non-small cell lung carcinoma to facilitate characterization of adrenal masses detected in an unmonitored environment (i.e., the radiologist on duty did not look at the acquired images before the patient left the scanner).One hundred consecutive patients with non-small cell lung carcinoma were referred for CT evaluation of the chest; chest and abdomen; or chest, abdomen, and brain. All underwent unenhanced CT of the adrenal glands before the requested CT examination. The morphologic features, size, and attenuation values of the adrenal masses were calculated. Attenuation values of adrenal masses from prior imaging, if available, were compared with those at follow-up imaging to classify these masses. Variable unit cost increase in obtaining these additional images was estimated.Fifteen adrenal masses were identified in 13 patients. In one patient, bilateral ill-defined adrenal masses were present. In 12 patients, 13 masses were sharply circumscribed: Seven were less than 10 HU and six were 20 HU or greater at unenhanced CT. Nine of these 12 patients received iodinated contrast material. Without the unenhanced CT, 10 adrenal masses in these nine patients would have been indeterminate for malignancy. In six of these nine patients, the adrenal mass was the only potential site of metastatic disease. The unenhanced CT data helped classify three of these masses as benign-10 HU or less- and three as indeterminate-greater than 10 HU.Unenhanced CT of the adrenal glands can prospectively characterize adrenal masses and obviate further examination in patients with lung carcinoma.

T he patient with acute abdominal pain represents one of the most common, most important, and most difficult practical problems that the general surgeon has to face [I]. Intestinal obstruction is responsible for approximately 20% of surgical admissions for acute abdominal conditions [2]. The small bowel is involved in 60-80% of cases of intestinal obstruction. In spite of advances in imaging and a better understanding of the pathophysiology of the small bowel, its obstruction is still frequently misdiagnosed [3]. The value of diagnostic imaging in such assessments lies in its ability to answer questions relevant to the clinical management of patients. According to Herlinger and Maglinte [4], the issues of concern to the surgical management of small-bowel obstruction that diagnostic procedures must address are the confirmation or exclusion of obstruction; the identification of the site, severity, and cause of the obstruction; and the possible presence of strangulation. Underlying these questions is the pivotal issue of whether early laparotomy is indicated or whether a trial of nonoperative management should be instituted. Radiology. because it is able to supply relevant answers to many of these questions, assumes considerable importance in this decision. The issue of how to use imaging resources in the midst of the ongoing changes in health care delivery has considerable practical importance. An erroneous choice of diagnostic procedures adds to the costs of workup and may delay diagnosis. This review examines the recent contributions of radiology, addresses controversies. and recommends an approach for the diagnostic triage of patients with possible intestinal obstruction.

The purpose of this study is to describe and illustrate the CT appearance of four cases of acute terminal ileitis induced by nontyphoidal Salmonella and Shigella infection and to review the radiographic and endoscopic findings of these entities.The medical records, CT examinations, and small bowel examinations of three patients with Salmonella ileitis and one patient with Shigella ileitis were retrospectively reviewed. CT examinations were done in four patients, colonoscopy in three patients, and small bowel examinations in two patients. Stool cultures established the diagnosis of nontyphoidal Salmonella enteritis in three patients and Shigella enteritis in one patient. The patients' symptoms and clinical findings resolved promptly following supportive therapy and appropriate antibiotic therapy.CT showed slight circumferential and homogeneous thickening of the terminal ileum over a segment of 10-15 cm in patients with Salmonella ileitis. Associated mild thickening of the wall of the colon was present in addition. Small bowel examination performed in one patient revealed a spastic terminal ileum with thickened mucosal folds. Colonoscopy revealed acute colitis involving the colon diffusely in one case, but sparing the distal 50 cm of the colon in one case. CT showed more pronounced thickening of the terminal ileum and a target configuration in the patient with Shigella ileitis. Small bowel examination revealed narrowing, irregular contour, several large nodular defects (thumbprinting), and a severely ulcerated mucosa affecting the terminal ileum. Colonoscopy revealed a normal colon and large ulcerations with fibropurulent exudate in the terminal ileum.In patients with severe Salmonella or Shigella infections or persistent and/or confusing clinical presentations, CT can play a complementary but important role in the initial diagnostic evaluation. It avoids clinical mismanagement, circumvents unnecessary invasive procedures, and contributes to the efficient workup and therapy in this group of individuals.

The purpose of this prospective study was to evaluate the role of CT in the diagnosis of patients with suspected acute small-bowel obstruction in whom clinical and plain radiographic findings were inconclusive.Fifty-seven nonconsecutive patients with suspected acute small-bowel obstruction were referred for CT to differentiate small-bowel obstruction from ileus (33 patients) or to establish the cause of obstruction (24 patients). The final diagnosis was established either by surgery (42 patients) or by the clinical evolution (15 patients). The change in the prescan diagnosis as to the presence, cause, and severity (strangulation) of small-bowel obstruction made on the basis of the CT findings was noted. Finally, the changes in therapy resulting from the CT information were recorded.CT correctly distinguished between small-bowel obstruction and ileus in all cases except one. CT enabled us to modify an erroneous clinical diagnosis correctly in 12 (21%) of 57 cases, including eight cases for which pre-CT diagnosis was ileus and four cases for which pre-CT diagnosis was small-bowel obstruction. CT allowed us to predict the cause of obstruction correctly in 33 (85%) of 39 patients with confirmed small-bowel obstruction but it failed to differentiate adhesions from internal hernias and radiation enteritis. The pre-CT diagnosis of the cause of obstruction was correctly changed because of CT findings in 17 (44%) of 39 patients with subsequently proved small-bowel obstruction. CT was able to identify strangulation in nine of the 12 patients with proved strangulation, which altered the pre-CT diagnosis in three patients. CT findings correctly modified the management in 12 (21%) of 57 patients, by changing either a conservative management to an operative one in 10 (18%), or an operative to a conservative one by differentiating ileus from obstruction in two patients.Our findings show that CT is a valuable diagnostic procedure in patients with suspected acute small-bowel obstruction. CT not only is useful in distinguishing obstruction from paralytic ileus, but it frequently establishes the cause of the obstruction and the presence of strangulation. CT findings lead to decisions to treat patients surgically in a significant number of patients.