American College Of Radiology Guidelines Research Articles

Comparison of the diagnostic accuracy of three current guidelines for the evaluation of asymptomatic pancreatic cystic neoplasms.

Asymptomatic pancreatic cysts are a common clinical problem but only a minority of these cases progress to cancer. Our aim was to compare the accuracy to detect malignancy of the 2015 American Gastroenterological Association (AGA), the 2012 International Consensus/Fukuoka (Fukuoka guidelines [FG]), and the 2010 American College of Radiology (ACR) guidelines.We conducted a retrospective study at 3 referral centers for all patients who underwent resection for an asymptomatic pancreatic cyst between January 2008 and December 2013. We compared the accuracy of 3 guidelines in predicting high-grade dysplasia (HGD) or cancer in resected cysts. We performed logistic regression analyses to examine the association between cyst features and risk of HGD or cancer.A total of 269 patients met inclusion criteria. A total of 228 (84.8%) had a benign diagnosis or low-grade dysplasia on surgical pathology, and 41 patients (15.2%) had either HGD (n = 14) or invasive cancer (n = 27). Of the 41 patients with HGD or cancer on resection, only 3 patients would have met the AGA guideline's indications for resection based on the preoperative cyst characteristics, whereas 30/41 patients would have met the FG criteria for resection and 22/41 patients met the ACR criteria. The sensitivity, specificity, positive predictive value, negative predictive value of HGD, and/or cancer of the AGA guidelines were 7.3%, 88.2%, 10%, and 84.1%, compared to 73.2%, 45.6%, 19.5%, and 90.4% for the FG and 53.7%, 61%, 19.8%, and 88% for the ACR guidelines. In multivariable analysis, cyst size >3 cm, compared to ≤3 cm, (odds ratio [OR] = 2.08, 95% confidence interval [CI] = 1.11, 4.2) and each year increase in age (OR = 1.07, 95% CI = 1.03, 1.11) were positively associated with risk of HGD or cancer on resection.In patients with asymptomatic branch duct-intraductal papillary mucinous neoplasms or mucinous cystic neoplasms who underwent resection, the prevalence rate of HGD or cancer was 15.2%. Using the 2015 AGA criteria for resection would have missed 92.6% of patients with HGD or cancer. The more "inclusive" FG and ACR had a higher sensitivity for HGD or cancer but lower specificity. Given the current deficiencies of these guidelines, it will be important to determine the acceptable rate of false-positives in order to prevent a single true-positive.

MP26: Rate and outcome of incidental findings among abdominal computed tomography scans in the emergency department

Introduction: With the increased accessibility of computed tomography (CT), use in the emergency department has increased. Increased use has lead to a reduction in missed diagnoses but also an increase in radiation burden and the increased likelihood of incidental findings. In this study, we sought to characterize the use of abdominal CTs at an academic tertiary center in order to quantify the rate and clinical significance incidental findings. Methods: This was a retrospective chart review of radiological database of all abdominal CT ordered by the emergency department from January 1st to March 21st 2015. Incidental findings requiring follow up were defined by the American college of radiology guidelines. Clinically significant incidental findings were defined as those that resulted in a finding of malignancy or comparably serious disease. Abdominal CTs were excluded if they were ordered together with CT thorax. The data was abstracted by one trained reviewer using a standardized data collection sheet and 10% of the data was verified by a second reviewer. Inter-rater reliability reported by Kappa statistic. Data were reported as mean and standard deviation. A sample size of 770 was calculated based on an expected difference in prevalence between significant and non-significant incidental findings of 80% (α=5%, Power=90%). Results: A total of 1882 imaging studies were included (56.3% female, age 59.4 years (16.3), CTAS 3 (1.3). The most common presenting complaints: abdominal pain (980, 52.1%), flank pain (196, 10.4%) and nausea/vomiting (111, 6%). Indications included rule out (r/o) obstructing renal stones/colic (329; 17.5%), r/o diverticulitis/colitis (307; 16.4%) and abdominal pain not yet differentiated (283; 15.1%). The most common final diagnoses as a result of CT were renal stone/colic (212, 11.3%), colitis/diverticulitis (191, 10.2%), and bowel obstruction (111, 6%).Incidental findings recommending further imaging occurred in 93 (4.9%). Of these, 43 were completed, and 15 resulted in clinically significant findings: cancer of the colon (2), lung (2), bladder (2), metastatic cancer (2), adnexa (4), endometrium (1), lymphoma (1), and venous thrombus (1). Conclusion: Incidental findings are far less common (5%) then previously reported (as high as 30%) and rarely clinically significant.

Evaluation of the indications for performing magnetic resonance imaging of the female pelvis at a referral center for cancer, according to the American College of Radiology criteria.

ObjectiveTo evaluate the indications for performing magnetic resonance imaging of the female pelvis at a referral center for cancer.Materials and MethodsThis was a retrospective, single-center study, conducted by reviewing medical records and imaging reports. We included 1060 female patients who underwent magnetic resonance imaging of the pelvis at a cancer center between January 2013 and June 2014. The indications for performing the examination were classified according to the American College of Radiology (ACR) criteria.ResultsThe mean age of the patients was 52.6 ± 14.8 years, and 49.8% were perimenopausal or postmenopausal. The majority (63.9%) had a history of cancer, which was gynecologic in 29.5% and nongynecologic in 34.4%. Of the patients evaluated, 44.0% had clinical complaints, the most common being pelvic pain (in 11.5%) and bleeding (in 9.8%), and 34.7% of patients had previously had abnormal findings on ultrasound. Most (76.7%) of the patients met the criteria for undergoing magnetic resonance imaging, according to the ACR guidelines. The main indications were evaluation of tumor recurrence after surgical resection (in 25.9%); detection and staging of gynecologic neoplasms (in 23.3%); and evaluation of pelvic pain or of a mass (in 17.1%).ConclusionIn the majority of the cases evaluated, magnetic resonance imaging was clearly indicated according to the ACR criteria. The main indication was local recurrence after surgical treatment of pelvic malignancies, which is consistent with the routine protocols at cancer centers.

Positron Emission Tomography/Computed Tomography for Gynecologic Malignancies.

Positron emission tomography/Computed tomography(PET/CT) is widely used for gynecologic cancers. To determine when PET/CT should be used for gynecologic cancers. PubMed was reviewed for articles on PET/CT of all gynecologic cancers. National Comprehensive Cancer Network, Society of Gynecologic Oncology, and American College of Radiology guidelines were reviewed. Whole-body PET/CT is useful for (1) initial staging of cervical and endometrial cancer, posttherapy assessment, radiation therapy planning, and posttreatment surveillance of cervical cancer, and (2) assessment of recurrence of cervical, endometrial, or ovarian cancer in the presence of symptoms. It is also useful for staging and recurrence of uterine sarcomas, and for staging of vulvar and vaginal cancer. Positron emission tomography/Computed tomography is clinically valuable for a variety of gynecologic cancers. PET/CT plays an important role in detection of initial disease and recurrence of gynecologic malignancies.

MDCT vs. MRI for incidental pancreatic cysts: measurement variability and impact on clinical management.

To investigate incidental pancreatic cysts (IPCs) size discrepancy in a cohort of patients receiving both computed tomography (CT) and magnetic resonance imaging (MRI) and its impact on clinical management based on the 2010 American College of Radiology (ACR) guidelines. This was a HIPAA-compliant, retrospective, IRB-approved study. Informed consent was waived. Patients with known IPCs and at least one case-pair, consisting of an abdominal CT and MRI examination within 180days between 05/1999 and 12/2011, were included. Maximum diameter of cysts was measured in both the CT and MR examinations. A subset of 30 patients was measured by three radiologists independently to assess inter-observer variability. Absolute difference in diameter measurements between CT and MRI was calculated. Influence of cyst size, cyst location, and patient characteristics such as weight, height, and body mass index (BMI) on variability of size measurements were evaluated. Clinical impact in terms of current ACR guidelines was assessed. Overall, 267 case-pairs of cysts in 113 patients were included in this study. 59/267 cysts were visualized on MRI but not on CT (22.1%, 95% CI 17.1%-27.1%; 32 patients, 64.6±11.7years, BMI 28.5±4.8kg/m2), with a median MRI cyst size of 7.8mm, IQR 6.0-9.0mm, range 2-17.8mm. 208 case-pairs in 113 patients with a mean BMI of 26.9±5.1kg/m2 (range 16.9-39.5kg/m2) and mean cysts size of 13.4±8.1mm (range 3-49mm) were seen in both CT and MRI. The mean absolute size difference for IPCs measured on MRI and CT was 2.1±1.8mm (median 1.5mm, IQR 0.9-2.9mm, range 0-9mm). Absolute size difference between CT and MRI measurements increased with size of the cyst (r=0.31, p<0.001), whereas location of the cyst did not influence the absolute difference between CT and MRI measurements (p=0.44). Patient weight and BMI had a negative correlation with the difference in cyst size between CT and MRI (weight r=-0.17, p=0.023; BMI r=-0.17, p=0.027), with cyst measurements being larger on MRI in thin patients and on CT in obese patients. Inter-reader variability was excellent (ICC=0.99). In 12/208 (5.7%, 95% CI 2.7%-9.1%), variability between CT and MRI would have changed ACR-based follow-up recommendation. There was a median difference of 1.5mm between measurements of IPCs on CT vs. MRI. If imaging modality was switched during follow-up, variability of measurements may lead to inappropriate change of follow-up regimen in 6% of all cases. A single follow-up CT for incidental IPCs does not seem sufficient due to a high number (22%) of missed IPCs on CT.

Computed tomography-related radiation exposure in children transferred to a Level I pediatric trauma center.

Pediatric trauma patients presenting to referring facilities (RF) often undergo computed tomography (CT) scans to identify injuries before transfer to a Level I pediatric trauma center (PTC). The purpose of our study was to evaluate RF compliance with the American College of Radiology (ACR) guidelines to minimize ionizing radiation exposure in pediatric trauma patients and to determine the frequency of additional or repeat CT imaging after transfer to a PTC. After institutional review board approval, a retrospective review of all pediatric trauma admissions from January 2010 to December 2011 at our American College of Surgeons Level I PTC was performed. Patient demographics, means of arrival, Injury Severity Score, and disposition were analyzed. Patients who underwent CT were grouped by means of arrival: those who were transferred from an RF versus those who presented primarily to the PTC. Compliance with ACR guidelines and need for additional or repeat CT scans were assessed for both groups. Six hundred ninety-seven children (aged <18 years) were identified, with a mean age of 10.6 years. Three hundred twenty-one (46%) patients presented primarily to the PTC. Three hundred seventy-six (54%) were transferred from an RF, of which 90 (24%) patients underwent CT imaging before transfer. CT radiation dosing information was available for 79 (88%) of 90 patients. After transfer, 8 (9%) of 90 of children imaged at an RF required additional CT scans. In comparison, 314 (98%) of 321 patients who presented primarily to the PTC and underwent CT received appropriate pediatric radiation dosing. Mean radiation dose at PTC was approximately half of that at RF for CT scans of the head, chest, and abdomen/pelvis (p < 0.01). Pediatric trauma patients transferred from RF often undergo CT scanning with higher than recommended radiation doses, potentially placing them at an increased carcinogenic risk. Fortunately, few RF patients required additional CT scans after PTC transfer. Finally, compliance with ACR radiation dose limit guidelines is better achieved at a PTC. Care management study, level IV.

An audit of elective outpatient magnetic resonance imaging in a tertiary South African public-sector hospital

Background: Increasing demand for magnetic resonance imaging (MRI) has resulted in longer waiting times for elective MRI, particularly in resource-limited healthcare environments.However, inappropriate imaging requests may also contribute to prolonged MRI waiting times. At the time of the present study, the waiting time for elective MRI studies at Tygerberg Hospital (TBH), a tertiary-level public-sector healthcare facility in Cape Town (South Africa),was 24 weeks.Objectives: To document the nature and clinical appropriateness of scheduled TBH outpatient MRI examinations.Method: A retrospective analysis of the referral forms of all elective outpatient MRIexaminations scheduled at TBH from 01 June to 30 November 2011 was conducted. Patient age, gender, clinical details, provisional diagnosis, examination requested and referring clinician were recorded on a customised data sheet. Two radiologists independently evaluated the appropriateness of each request by comparing the clinical details and the provisional diagnosis provided with the 2012 American College of Radiology (ACR) guidelines for the appropriate use of MRI.Results: Four hundred and sixty-six patients (median age 42 years; interquartile range 19–55) who had 561 examinations were scheduled in the review period; 70 (15%) were children less than 6 years old. Neurosurgery (n = 164; 35%), orthopaedic (n = 144; 31%),neurology (n = 53; 11%) and paediatric (n = 27; 6%) outpatients accounted for the majority(81%) of referrals; 464 (99.6%) were from specialist clinics. MRIs of the spine (n = 314; 56%),brain (n = 152; 27%) and musculoskeletal system (n = 70, 13%) accounted for more than 95%of the investigations. In 455 cases (98%), the referral was congruent with published ACR guidelines for appropriate MRI utilisation.Conclusion: Scheduled outpatient MRI examinations at TBH reflect optimal clinical use of a limited resource. MRI utilisation is largely confined to traditional neuro-imaging. Any initiative to decrease the elective MRI waiting time should focus on service expansion.

Erratum: Using the ACR CT accreditation phantom for routine image quality assurance on both CT and CBCT imaging systems in a radiotherapy environment.

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Using the ACR CT accreditation phantom for routine image quality assurance on both CT and CBCT imaging systems in a radiotherapy environment.

Image‐guided radiation therapy using cone‐beam computed tomography (CBCT) is becoming routine practice in modern radiation therapy. The purpose of this work was to develop an imaging QA program for CT and CBCT units in our department, based on the American College of Radiology (ACR) CT accreditation phantom. The phantom has four testing modules, permitting one to test CT number accuracy, slice width, low contrast resolution, image uniformity, in‐plane distance accuracy, and high‐contrast resolution reproducibly with suggested window/levels for image analysis. Additional tests for contrast‐to‐noise ratio (CNR) and noise were added using the polyethylene and acrylic plugs. Baseline values were obtained from CT simulator images acquired on a Phillips Brilliance Big Bore CT simulator and CBCT images acquired on three Varian CBCTs for the imaging protocols most used clinically. Images were then acquired quarterly over a period of two years. Images were exported via DICOM and analyzed manually using OsiriX. Baseline values were used to ensure that image quality remained consistent quarterly, and baselines were reset at any major maintenance or recalibration. Analysis of CT simulator images showed that image quality was within ACR guidelines for all tested scanning protocols. All three CBCT systems were unable to distinguish the low‐contrast resolution plugs and had the same high‐contrast resolution over all imaging protocols. Analysis of CBCT results over time determined a range of values that could be used to establish quantitative tolerance levels for image quality deterioration. While appropriate for the helical CT, the ACR phantom and guidelines could be modified to be more useful in evaluating CBCT systems. In addition, the observed values for the CT simulator were well within ACR tolerances.PACS numbers: 87.57.Q‐, 87.57.qp, 87.57.C‐

Incidental findings on cone beam computed tomographic images: a Pandora's box?

Incidental findings on cone beam computed tomographic images: a Pandora's box?

Changes in Risk of Immediate Adverse Reactions to Iodinated Contrast Media by Repeated Administrations in Patients with Hepatocellular Carcinoma

BackgroundTo elucidate whether repeated exposures to iodinated contrast media increase the risk of adverse reaction.Materials and MethodsWe retrospectively reviewed 1,861 patients with hepatocellular carcinoma who visited authors’ institution, a tertiary referral center, between 2004 and 2008. We analyzed cumulative probability of adverse reactions and risk factors. We categorized all symptoms into hypersensitivity reactions, physiologic reactions, and other reactions, according to the American College of Radiology guidelines, and evaluated each category as an event. We estimated the association between hazard for adverse reactions and the number of cumulative exposures to contrast media. We also evaluated subsequent contrast media injections and adverse reactions.ResultsThere were 23,684 contrast media injections in 1,729 patients. One hundred and thirty-two patients were excluded because they were given no contrast media during the study period. Adverse reactions occurred in 196 (0.83%) patients. The cumulative incidence at 10th, 20th, and 30th examination was 7.9%, 15.2%, and 24.1%, respectively. Presence of renal impairment was found to be one of risk factors for adverse reactions. The estimated hazard of overall adverse reaction gradually decreased until around 10th exposure and rose with subsequent exposures. The estimated hazard of hypersensitivity showed V-shaped change with cumulative number of exposures. The estimated hazard of physiologic reaction had a tendency toward decreasing and that of other reaction had a tendency toward increasing. Second adverse reaction was more severe than the initial in only one among 130 patients receiving subsequent injections.ConclusionRepeated exposures to iodinated contrast media increase the risk of adverse reaction.

Appropriateness of Imaging Studies Ordered by Emergency Medicine Residents: Results of an Online Survey

The purpose of this study is to determine the proficiency of emergency medicine residents in selecting appropriate radiologic examinations for specific clinical scenarios and to ascertain whether their training improves competency in this area over the course of their residency. An online multiple-choice questionnaire was created. It included 10 clinical scenarios excerpted from the American College of Radiology Appropriateness Criteria guidelines and instructed residents to select the most appropriate initial imaging study. A link and invitation to the survey were e-mailed to the residency program directors and coordinators of all American Council for Graduate Medical Education-accredited emergency medicine residency training programs with the request that they be forwarded to their current residents. Responses were graded, with correct answers derived from the American College of Radiology guidelines. Results were stratified by year of emergency medicine training, and an analysis of variance was performed. A total of 583 residents from at least 77 different emergency medicine residency training programs completed the survey. Overall, the average number of questions answered correctly was 7.1 of 10 (SD, 1.2). First-through fourth-year residents averaged 6.9 (SD, 1.3), 7.1 (SD, 1.2), 7.1 (SD, 1.1), and 7.5 (SD, 1.1) correct answers, respectively. Analysis of variance found no significant difference between the scores of the four classes (p = 0.09). Emergency medicine residents do not show significant improvement over the course of their residency in their ability to choose appropriate imaging studies. This finding suggests that there is a role for more-rigorous focused instruction to better familiarize residents with appropriateness guidelines for diagnostic imaging selection.

Comparison of NCCN and ACR Guidelines Regarding Treatment of Lung, Prostate, and Head-and-Neck Cancers

To present and compare treatment guidelines from the National Comprehensive Cancer Network (NCCN) and American College of Radiology (ACR) for 3 solid tumor sites in order to estimate the rate concordance of recommendations.

Quantitative ultrasound measurements of bone strength in female adolescent idiopathic scoliosis patients

Methods This study was approved by the Human Research Ethic Committee of the School of Medicine, Jiaotong University, China. Eighty nine untreated female AIS patients were recruited in this study. The age range was from 10 to 16 years. Those who were using calcium supplements and those who had history of bone diseases were excluded from the study. The diagnoses of all AIS were confirmed by radiography based on American College of Radiology Guidelines and Recommendations. Cobb’s angles ranged from 10-52° (average 27.13°). The types of scoliosis included thoracic, lumbar, thoracolumbar and double curvatures. Patients’ menstrual conditions and family history were also taken in consideration. SOS was measured (by Sunlight omnisense) in the distal 1/3 of the radial bones. Data were compared to age and gender-matched norms (standard SOS value provided by Sunlight system). Results Radial SOS was significantly reduced in AIS patients compared to non-AIS subjects (P < 0.01); the radial SOS was also correlated to the age of the onset of menstrual cycle (lower in pre-menstrual cycle patients, 3626.92±124.35 vs. 3702.68±192.23, P<0.05). No significant correlations were found among the type of curvatures, the degree of Cobb’s angle, family history and bone SOS (P < 0.05).

SU-D-213CD-06: Workflow and Safety Systems of a Linac-MR Sim-Brachytherapy MRgRT™ Facility.

To develop the operational workflow and safety systems of a magnetic resonance-guided radiotherapy system (MRgRT™), which comprises an MR scanner on rails that travels between a linac vault, MR simulation room and brachytherapy suite. To develop a safe and streamlined clinical workflow, we conducted a comprehensive process review based on a layered approach to overall MRgRT safety that included i) facility design, (ii) workflow iii) system design and interlocks and iv) policies and procedures. We applied existing guidelines for MR and radiation safety, and employed system-level failure modes and effects analyses to design the MRgRT facility and clinical procedures. In the MRgRT system configuration, the MR and treatment systems are physically decoupled and used independently requiring novel administration of existing MR and radiation guidelines. A key element for the safe operation of the moving MR unit is the concept that all three rooms represent zone 4 areas (American College of Radiology guidelines). Using this concept, we applied MR guidelines to develop safe procedures for the overall suite, including screening of all persons entering the suite in zone 2 and control of ferromagnetic materials. We generated a clinical workflow that ensures expedient and safe transition between MR imaging and treatment delivery in both the linac and brachytherapy rooms. In addition, we designed emergency protocols for MRgRT, which helped drive requirements for the facility and system design, e.g., need for an accessible MR-safe stretcher. We designed the first comprehensive description of the MRgRT workflow, interlocking systems and safety procedures. With this layered approach to safety, we addressed critical aspects regarding safe operation and workflow for the system and provided multiple redundancies for key processes. Coupled with customized staff training, the proposed design ensures the safe operation of the MRgRT facility. This work has received research personnel support from IMRIS.

Conspicuity of Microcalcifications on Digital Screening Mammograms Using Varying Degrees of Monitor Zooming

American College of Radiology guidelines suggest that digital screening mammographic images should be viewed at the full resolution at which they were acquired. This slows interpretation speed. The aim of this study was to examine the effect of various levels of zooming on the detection and conspicuity of microcalcifications. Six radiologists viewed 40 mammographic images five times in different random orders using five different levels of zooming: full resolution (100%) and 30%, 61%, 88%, and 126% of that size. Thirty-three images contained microcalcifications varying in subtlety, all associated with breast cancer. The clusters were circled. Seven images contained no malignant calcifications but also had randomly placed circles. The radiologists graded the presence or absence and visual conspicuity of any calcifications compared to calcifications in a reference image. They also counted the microcalcifications. The radiologists saw the microcalcifications in 94% of the images at 30% size and in either 99% or 100% of the other tested levels of zooming. Conspicuity ratings were worst for the 30% size and fairly similar for the others. Using the 30% size, two radiologists failed to see the microcalcifications on either the craniocaudal or mediolateral oblique view taken from one patient. Interobserver agreement regarding the number of calcifications was lowest for the 30% images and second lowest for the 100% images. Images at 30% size should not be relied on alone for systematic scanning for microcalcifications. The other four levels of magnification all performed well enough to warrant further testing.

A review of methods of clinical image quality evaluation in mammography

Purpose Consistency in evaluation of mammography images in research and clinical practice is dependent on a standardised clinical image quality evaluation system. Currently two such systems are available—one developed by the American College of Radiology (ACR) and the other by the European Commission (EU guidelines). The purpose of this study was to review mammography clinical evaluation methods in research studies and their adherence to these systems . Method A total of 23 research articles were reviewed from the period 2000–2006, 11 of these studies used digital images. The focus of the review was the criteria and rating scales used. Results Only 5 studies used either the ACR (3) or EU guidelines (2). The remainder included aspects of these systems together with a range of other criteria and rating scales. Variation was found in the categories of criteria used, number of criteria, the descriptors of the criteria and the instructions used to evaluate the criteria. Instructions were frequently not specific and open to individual interpretation. Although breast density is an important criterion of image quality and contributes to perception of breast lesions, inclusion of this criterion was not universal, and even when used the area of breast density to be evaluated was not identified, thus enhancing inter-observer variability. Scales that were absolute or relative were used for evaluation, all of which incorporated inconsistent numbers of steps. Conclusion Low adherence to ACR and EU Guidelines has resulted in considerable variation in the evaluation methods used in research studies. The implications of this variability are considerable both for evaluation of image quality in research outcomes and clinical practice.

Computed Tomographic Colonography and High-Risk Adenomas: A Gap in the Guidelines?

Computed Tomographic Colonography and High-Risk Adenomas: A Gap in the Guidelines?

Nonionic Iodinated Intravenous Contrast Material–related Reactions: Incidence in Large Urban Children's Hospital—Retrospective Analysis of Data in 12 494 Patients

To examine the incidence and severity of nonionic intravenous contrast material reactions in a large pediatric patient population. Electronic records on all consecutive patients at a tertiary care pediatric hospital who received ioversol contrast material over a 7-year period for computed tomographic or excretory urographic studies were reviewed, yielding individual contrast material injection events in 12,494 patients up to 21 years of age. There were 6600 male patients and 5894 female patients. Contrast material reactions were categorized as mild, moderate, or severe according to American College of Radiology guidelines. Logistic regression analysis was performed to evaluate effects of age, sex, season, and study year on the presence of an intravenous contrast material reaction. There were 57 adverse events related to nonionic iodinated intravenous contrast material in 12,494 consecutive pediatric and young adult patients. Incidence of a contrast material reaction was 0.46% (57 of 12,494), or one in 200 patients. Incidence of a type I (mild) contrast material reaction was 0.38% (47 of 12,494), or one in 250 patients. Incidence of a type II (moderate) reaction was 0.08% (10 of 12,494), or one in 1000 patients. There were no severe (type III) reactions. The average age of patients with a contrast material reaction (12.9 years +/- 4.3 [standard deviation]) was 3.4 years older (P < .001) than the average age of all patients in the study (9.5 years +/- 5.9). There was a significant relationship between patient age and incidence of contrast material reaction per 1000 studies (P = .003), independent of sex, season, and year of study. Adverse reactions to intravenous administration of a nonionic contrast material (ioversol) are rare in children and increase in frequency with advancing age. The great majority of reactions in children are mild.

The Influence of Increased Ambient Lighting on Mass Detection in Mammograms

Recent research has provided evidence that in reading rooms equipped with liquid crystal displays (LCDs), a measured increase of ambient lighting may improve clinicians' detection performance. In agreement with this research, the American College of Radiology (ACR) has recommended a moderate increase of ambient lighting in mammography reading rooms. This study was designed to examine the effect of a controlled increase of ambient lighting in mammography reading rooms on the diagnostic performance of breast imaging radiologists. Four breast imaging radiologists read 86 mammograms (43 containing subtle cancerous masses and 43 normal) under low (E = 1 lux) and elevated (E = 50 lux) ambient lighting levels on a Digital Imaging and Communications in Medicine-calibrated, medical-grade LCD. Radiologists were asked to identify cancerous masses and to rate their detection confidence. Observer areas under the curve (AUCs) were calculated using a receiver-operating characteristic analysis of fully paired results. Additionally, average observer selection times under both ambient lighting levels were determined. Average radiologist AUCs decreased with elevated ambient lighting (0.78 +/- 0.03 to 0.72 +/- 0.04). Observer performance differences, however, were of the same order of magnitude as interobserver variability and were not statistically significant. Average selection times under increased ambient lighting remained constant or decreased, with the greatest decrease occurring for false-positive (20.4 +/- 18.9 to 14.4 +/- 9.6 seconds) and true-positive (18.0 +/- 13.8 to 12.9 +/- 9.4 seconds) selections. The results agree with those of previous studies in that observer performance differences under a controlled increase of ambient lighting are not statistically significant. On the basis of these findings and ACR guidelines, a moderate increase of ambient lighting in mammography reading rooms is still suggested, but further research with additional cases and observers should be considered.