Cine MRI of Tracheal Dynamics in Healthy Volunteers and Patients With Tracheobronchomalacia.

OBJECTIVE: Bronchoscopy and MDCT are routinely used to assess tracheobronchomalacia (TBM). Recently, dynamic MRI (cine MRI) has been proposed as a radiation-free alternative to MDCT. In this study, we tested cine MRI assessment of airway dynamics during various breathing conditions and compared cine MRI and MDCT measurements in healthy volunteers and patients with suspected TBM. CONCLUSION: Cine MRI was found to be a technically feasible alternative to MDCT for assessing central airway dynamics.

Differentiating between Subsolid and Solid Pulmonary Nodules at CT: Inter- and Intraobserver Agreement between Experienced Thoracic Radiologists.

PURPOSE: To quantify the reproducibility and accuracy of experienced thoracic radiologists in differentiating between subsolid and solid pulmonary nodules at CT. MATERIALS AND METHODS: The institutional review board of Beth Israel Deaconess Medical Center approved this multicenter study. Six thoracic radiologists, with a mean of 21 years of experience in thoracic radiology (range, 17-22 years), selected images of 10 solid and 10 subsolid nodules to create a database of 120 nodules; this selection served as the reference standard. Each radiologist then interpreted 120 randomly ordered nodules in two different sessions that were separated by a minimum of 3 weeks. The radiologists classified whether or not each nodule was subsolid. Inter- and intraobserver agreement was assessed with a κ statistic. The number of correct classifications was calculated and correlated with nodule size by using Bland-Altman plots. The relationship between disagreement and nodule morphologic characteristics was analyzed by calculating the intraclass correlation coefficient. RESULTS: Interobserver agreement (κ) was 0.619 (range, 0.469-0.745; 95% confidence interval (CI): 0.576, 0.663) and 0.670 (range, 0.440-0.839; 95% CI: 0.608, 0.733) for interpretation sessions 1 and 2, respectively. Intraobserver agreement (κ) was 0.792 (95% CI: 0.750, 0.833). Averaged for interpretation sessions, correct classification was achieved by all radiologists for 58% (70 of 120) of nodules. Radiologists agreed with their initial determination (the reference standard) in 77% of cases (range, 45%-100%). Nodule size weakly correlated with correct classification (long axis: Spearman rank correlation coefficient, rs = 0.161 and P = .049; short axis: rs = 0.128 and P = .163). CONCLUSION: The reproducibility and accuracy of thoracic radiologists in classifying whether or not a nodule is subsolid varied in the retrospective study. This inconsistency may affect surveillance recommendations and prognostic determinations.

Screening for Lung Cancer With Low-Dose Computed Tomography: Grand Rounds Discussion From the Beth Israel Deaconess Medical Center.

In December 2013, the U.S. Preventive Services Task Force recommended screening for lung cancer with low-dose computed tomography (LDCT) for selected current and former smokers. The Task Force based the recommendation primarily on the results of the NLST (National Lung Screening Trial). In this trial, patients randomly assigned to LDCT screening for 3 years had lower rates of both lung cancer-specific mortality and all-cause mortality (relative risk reduction, 6.7% [95% CI, 1.2% to 13.6%]; absolute risk reduction, 0.46% [CI, 0% to 0.9%]). Clinicians and health systems confront questions and challenges as they begin to implement lung cancer screening. This paper summarizes a conference during which an internist and a radiologist discuss the application of the Task Force recommendation to an individual patient.

Impact of lung cancer screening results on participant health-related quality of life and state anxiety in the National Lung Screening Trial.

BACKGROUND: Low-dose computed tomography (LDCT) lung screening has been associated with a 20% reduction in lung cancer mortality. A major barrier to the adoption of lung screening is the potential negative psychological impact of a false-positive (FP) screen, occurring in 20% to 50% of those screened. The objective of this study was to assess the impact of abnormal findings on health-related quality of life (HRQoL) and anxiety in the American College of Radiology (ACRIN)/National Lung Screening Trial (NLST). METHODS: The NLST was a randomized screening trial comparing LDCT with chest X-ray screening (CXR). This study was part of the original protocol. A total of 2812 participants at 16 of 23 ACRIN sites who had baseline HRQoL assessments were asked to complete the Short Form-36 and the State Trait Anxiety Inventory (form Y-1) questionnaires to assess short-term (1 month) and long-term (6 months) effects of screening. FP were lung cancer-free at 1 year, and true-positives (TP) were not. RESULTS: Of the total participants, 1024 (36.4%) participants were FP, 63 (2.2%) were TP, 344 (12.2%) had significant incidental findings (SIFs), and 1381 (49.1%) had negative screens. Participants had been randomized to LDCT (n = 1947) and CXR (n = 865). Short-term and long-term HRQoL and state anxiety did not differ across participants with FP, SIF, or negative screens. Short-term and long-term HRQoL were lower and anxiety was higher for TP participants compared to participants with FP, SIF, and negative screens. CONCLUSIONS: In a large multicenter lung screening trial, participants receiving a false-positive or SIF screen result experienced no significant difference in HRQoL or state anxiety at 1 or at 6 months after screening relative to those receiving a negative result.

Incidentally detected lung nodules: clinical predictors of adherence to Fleischner Society surveillance guidelines.

OBJECTIVE: The objective of this study was to determine adherence to incidentally detected lung nodule computed tomographic (CT) surveillance recommendations and identify demographic and clinical factors that increase the likelihood of CT surveillance. MATERIALS AND METHODS: A total of 419 patients with incidentally detected lung nodules were included. Recorded data included patient demographic, radiologic, and clinical characteristics and outcomes at a 4-year follow-up. Multivariate logistic regression models determined the factors associated with likelihood of recommended CT surveillance. RESULTS: At least 1 recommended surveillance chest CT was performed on 48% of the patients (148/310). Computed tomographic result communication to the patient (odds ratio [OR], 2.2; P = 0.006; confidence interval [CI], 1.3-4.0) or to the referring physician (OR, 2.8; P = 0.001; CI, 1.7-4.5) and recommendation of a specific surveillance time interval (OR, 1.7; P = 0.023; CI, 1.08-2.72) increased the likelihood of surveillance. Other demographic, radiologic, and clinical factors did not influence surveillance. CONCLUSIONS: Documented physician and patient result communication as well as the recommendation of a specific surveillance time interval increased the likelihood of CT surveillance of incidentally detected lung nodules.

Perceived benefits of a radiology resident mentoring program: comparison of residents with self-selected vs assigned mentors.

PURPOSE: It has been suggested that assigned mentoring relationships are less successful than those that develop by free choice. This study evaluates radiology residents' overall experience with a mentoring program and compares the responses of those who self-selected mentors with those who were assigned mentors. METHODS: A voluntary Web-based survey was sent to 27 radiology residents in postgraduate years 3-5. Data collected included the following: year in residency, method of mentor assignment, duration of relationship, frequency and types of communication, perceived value of mentoring, overall satisfaction with the program, and the perceived impact of mentoring. RESULTS: Twenty-five of 27 residents (93%) responded, with 14 having self-selected mentors (56%) and 11 having assigned mentors (44%). Both groups unanimously agreed that mentoring is beneficial or critical to their training; however, those residents with self-selected mentors were significantly more satisfied with the mentoring program (4 vs 3.3; P = .04) and more likely to consider their mentor as their primary mentor compared with those with assigned mentors (11 [79%] vs 4 [36%]; P = .049). Although all residents perceived a benefit, residents with self-selected mentors rated almost all mentoring parameters more positively than those with assigned mentors, although most of these parameters did not reach statistical significance. CONCLUSION: Residents highly value the importance of mentoring. However, residents who self-select their mentors are more likely to be satisfied with a mentoring program.

Computed tomography angiography for suspected pulmonary embolism: comparison of 2 adaptive statistical iterative reconstruction blends to filtered back-projection alone.

OBJECTIVE: The objective of this study was to analyze pulmonary computed tomography angiography image quality and pulmonary embolism (PE) depiction comparing 2 blends of adaptive statistical iterative reconstruction (ASIR) to filtered back-projection alone. METHODS: Seventy-nine consecutive patients (49 women, 30 men; 52 ± 18 years) underwent pulmonary computed tomography angiography (120 kVp, 100-600 mA) reconstructed with filtered back-projection alone (ASIR0), 30% ASIR (ASIR30), and 50% ASIR (ASIR50) for this institutional review board-approved study. Two radiologists independently assessed PE depiction and vascular characterization, which was correlated with body mass index. RESULTS: Twelve patients (15%) had PE. No difference in PE depiction (P = 0.536), pulmonary arterial attenuation (P = 0.22-0.99), or subjective vascular characterization score (P = 0.58-.016) was observed for either blend. ASIR30 and ASIR50 achieved higher signal-to-noise ratio (P = 0.001-0.003). Body mass index inversely correlated with vascular characterization scores (P < 0.001). CONCLUSIONS: ASIR0, ASIR30, and ASIR50 accurately depict PE using the imaging parameters described. ASIR30 and ASIR50 improve objective image quality without altering subjective vascular characterization scores particularly when body mass index was less than 30 kg/m.

Advanced large airway CT imaging in children: evolution from axial to 4-D assessment.

Continuing advances in multidetector computed tomography (MDCT) technology are revolutionizing the non-invasive evaluation of congenital and acquired large airway disorders in children. For example, the faster scanning time and increased anatomical coverage that are afforded by MDCT are especially beneficial to children. MDCT also provides high-quality multiplanar 2-dimensional (2-D), internal and external volume-rendering 3-dimensional (3-D), and dynamic 4-dimensional (4-D) imaging. These advances have enabled CT to become the primary non-invasive imaging modality of choice for the diagnosis, treatment planning, and follow-up evaluation of various large airway disorders in infants and children. It is thus essential for radiologists to be familiar with safe and effective techniques for performing MDCT and to be able to recognize the characteristic imaging appearances of large airway disorders affecting children.

Proximal pulmonary vein stenosis detection in pediatric patients: value of multiplanar and 3-D VR imaging evaluation.

BACKGROUND: One of the important benefits of using multidetector computed tomography (MDCT) is its capability to generate high-quality two-dimensional (2-D) multiplanar (MPR) and three-dimensional (3-D) images from volumetric and isotropic axial CT data. However, to the best of our knowledge, no results have been published on the potential diagnostic role of multiplanar and 3-D volume-rendered (VR) images in detecting pulmonary vein stenosis, a condition in which MDCT has recently assumed a role as the initial noninvasive imaging modality of choice. OBJECTIVE: The purpose of this study was to compare diagnostic accuracy and interpretation time of axial, multiplanar and 3-D VR images for detection of proximal pulmonary vein stenosis in children, and to assess the potential added diagnostic value of multiplanar and 3-D VR images. MATERIALS AND METHODS: We used our hospital information system to identify all consecutive children (< 18 years of age) with proximal pulmonary vein stenosis who had both a thoracic MDCT angiography study and a catheter-based conventional angiography within 2 months from June 2005 to February 2012. Two experienced pediatric radiologists independently reviewed each MDCT study for the presence of proximal pulmonary vein stenosis defined as ≥ 50% of luminal narrowing on axial, multiplanar and 3-D VR images. Final diagnosis was confirmed by angiographic findings. Diagnostic accuracy was compared using the z-test. Confidence level of diagnosis (scale 1-5, 5 = highest), perceived added diagnostic value (scale 1-5, 5 = highest), and interpretation time of multiplanar or 3-D VR images were compared using paired t-tests. Interobserver agreement was measured using the chance-corrected kappa coefficient. RESULTS: The final study population consisted of 28 children (15 boys and 13 girls; mean age: 5.2 months). Diagnostic accuracy based on 116 individual pulmonary veins for detection of proximal pulmonary vein stenosis was 72.4% (84 of 116) for axial MDCT images, 77.5% (90 of 116 cases) for multiplanar MDCT images, and 93% (108 of 116 cases) for 3-D VR images with significantly higher accuracy with 3-D VR compared to axial (z = 4.17, P < 0.001) and multiplanar (z = 3.34, P < 0.001) images. Confidence levels for detection of proximal pulmonary vein stenosis were significantly higher with 3-D VR images (mean level: 4.6) compared to axial MDCT images (mean level: 1.7) and multiplanar MDCT images (mean level: 2.0) (paired t-tests, P < 0.001). Thus, 3-D VR images (mean added diagnostic value: 4.7) were found to provide added diagnostic value for detecting proximal pulmonary vein stenosis (paired t-test, P < 0.001); however, multiplanar MDCT images did not provide added value (paired t-test, P = 0.89). Interpretation time was significantly longer and interobserver agreement was higher when using 3-D VR images than using axial MDCT images or MPR MDCT images for diagnosing proximal pulmonary vein stenosis (paired t-tests, P < 0.001). CONCLUSIONS: Use of 3-D VR images in the diagnosis of proximal pulmonary vein stenosis in children significantly increases accuracy, confidence level, added diagnostic value and interobserver agreement. Thus, the routine use of this technique should be encouraged despite its increased interpretation time.

Dynamic expiratory tracheal collapse in morbidly obese COPD patients.

Morbid obesity may influence several aspects of airway function. However, the effect of morbid obesity on expiratory tracheal collapse in COPD patients is unknown. We thus prospectively studied 100 COPD patients who underwent full pulmonary function tests (PFTs), 6-minute walk test (6MWT), Saint George's Respiratory Questionnaire (SGRQ), and low-dose CT at total lung capacity and during dynamic exhalation with spirometric monitoring. We examined correlations between percentage dynamic expiratory tracheal collapse and body mass index (BMI). The association between tracheal collapse and BMI was compared to a control group of 53 volunteers without COPD. Patients included 48 women and 52 men with mean age 65 ± 7 years; BMI 30 ± 6; FEV1 64 ± 22% predicted and percentage expiratory collapse 59 ± 19%. Expiratory collapse was significantly associated with BMI (69 ± 12% tracheal collapse among 20 morbidly obese patients with BMI ≥ 35 compared to 57 ± 19% in others, p = 0.002, t-test). In contrast, there was no significant difference in collapse between healthy volunteers with BMI ≥ 35 and < 35. COPD patients with BMI ≥ 35 also demonstrated shorter 6MWT distances (340 ± 139 m vs. 430 ± 139 m, p = 0.003) and higher (worse) total SGRQ scores (48 ± 19 vs. 36 ± 20, p = 0.013) compared to those with BMI < 35. In light of these results, clinicians should consider evaluating for excessive expiratory tracheal collapse when confronted with a morbidly obese COPD patient with greater quality of life impairment and worse exercise performance than expected based on functional measures.

Computed tomography screening for lung cancer.

IMPORTANCE: Low-dose computed tomography (CT) screening was shown to reduce lung cancer-specific mortality in a large randomized trial of a high-risk population. The decision to pursue CT screening for lung cancer is a timely question raised by individuals at risk of lung cancer and by their health care practitioners. OBJECTIVES: To discuss the evidence for use of chest x-rays and low-dose CT in screening for lung cancer; to describe potential benefits, harms, and uncertainties of CT screening; and to review current guidelines for CT screening. EVIDENCE REVIEW: MEDLINE and the Cochrane Library were searched from 1984 to 2012. Additional citations were obtained from lists of references from select research and review articles on this topic. Evidence was graded using the American Hospital Association level of evidence guidelines. FINDINGS: Low-dose CT screening has been associated with a 20% reduction in lung cancer mortality in a large randomized controlled trial (National Lung Screening Trial [NLST]) of a high-risk population. Mortality data have not yet been reported for 5 other randomized controlled trials, and the sample sizes were too small to detect a meaningful difference in 2 other completed trials. A major risk of CT screening is a high false-positive rate, with associated risks and costs associated with follow-up CT scans and the potential for more invasive diagnostic procedures. Published guidelines for screening indicate a consensus that screening may be indicated for individuals who meet entry criteria for the NLST, but some guidelines expand their recommendations for screening beyond these criteria. CONCLUSIONS AND RELEVANCE: Individuals at high risk of lung cancer who meet the criteria for CT screening in published guidelines should participate in an informed and shared decision-making process by discussing the potential benefits, harms, and uncertainties of screening with their physicians.

Children suspected of having pulmonary embolism: multidetector CT pulmonary angiography--thromboembolic risk factors and implications for appropriate use.

PURPOSE: To evaluate thromboembolic risk factors for pulmonary embolism (PE) detected by using computed tomographic (CT) pulmonary angiography in children and to determine whether such information could be used for more appropriate use of CT pulmonary angiography in this patient population. MATERIALS AND METHODS: The institutional review board approved this HIPAA-compliant retrospective study and waived the need for patient informed consent. Two hundred twenty-seven consecutive CT pulmonary angiography studies in 227 pediatric patients who underwent CT pulmonary angiography for clinically suspected PE at a single large pediatric referral hospital between July 2004 and March 2011 were evaluated. Age, sex, referral setting, and D-dimer result, as well as seven possible risk factors, were compared between patients with and those without PE. Multiple logistic regression modeling was used to identify the independent risk factors of PE. Receiver operating characteristic curve analysis was applied to determine the optimal cutoff number of risk factors for predicting a positive CT pulmonary angiography result for PE in children. RESULTS: Thirty-six (16%) of 227 CT pulmonary angiography studies were positive for PE. Five risk factors, including immobilization (P < .001), hypercoagulable state (P = .003), excess estrogen state (P = .002), indwelling central venous line (P < .001), and prior PE and/or deep venous thrombosis (P < .001), were found to be significant independent risk factors for PE. With use of two or more risk factors as the clinical threshold, the sensitivity of a positive PE result was 89% (32 of 36 patients), and the specificity was 94% (180 of 191 patients). CONCLUSION: It is unlikely for CT pulmonary angiography results to be positive for PE in children with no thromboembolic risk factors. The use of risk factor assessment as a first-line triage tool has the potential to guide more appropriate use of CT pulmonary angiography in children, with associated reductions in radiation exposure and costs.

American Thoracic Society documents: an official American Thoracic Society/Society of Thoracic Radiology Clinical Practice Guideline--Evaluation of Suspected Pulmonary Embolism in Pregnancy.

BACKGROUND: Pulmonary embolism (PE) is a leading cause of maternal mortality in the developed world. Along with appropriate prophylaxis and therapy, prevention of death from PE in pregnancy requires a high index of clinical suspicion followed by a timely and accurate diagnostic approach. METHODS: To provide guidance on this important health issue, a multidisciplinary panel of major medical stakeholders was convened to develop evidence-based guidelines for evaluation of suspected pulmonary embolism in pregnancy using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) system. In formulation of the recommended diagnostic algorithm, the important outcomes were defined to be diagnostic accuracy and diagnostic yield; the panel placed a high value on minimizing cumulative radiation dose when determining the recommended sequence of tests. RESULTS: Overall, the quality of the underlying evidence for all recommendations was rated as very low or low with some of the evidence considered for recommendations extrapolated from studies of the general population. Despite the low quality evidence, strong recommendations were made for three specific scenarios: performance of chest radiography (CXR) as the first radiation-associated procedure; use of lung scintigraphy as the preferred test in the setting of a normal CXR; and performance of computed-tomographic pulmonary angiography (CTPA) rather than digital subtraction angiography (DSA) in a pregnant woman with a nondiagnostic ventilation-perfusion (V/Q) result. DISCUSSION: The recommendations presented in this guideline are based upon the currently available evidence; availability of new clinical research data and development and dissemination of new technologies will necessitate a revision and update.

Pulmonary embolism detected by pulmonary MDCT angiography in older children and young adults: risk factor assessment.

OBJECTIVE: The purpose of this article is to determine the risk factors for pulmonary embolism (PE) among older children and young adults who underwent pulmonary CT angiography (CTA) for evaluation of clinically suspected PE. MATERIALS AND METHODS: We used our hospital information system to retrospectively identify all consecutive patients 19-25 years old who underwent pulmonary CTA for evaluation of clinically suspected PE between July 2004 and March 2011. Two experienced pediatric radiologists retrospectively and independently reviewed a series of 116 consecutive pulmonary CTA studies from this population. Each examination was reviewed for the presence of PE. Seven possible risk factors (immobilization, prior PE or deep venous thrombosis [DVT], cardiac disease, malignancy, hypercoagulable state, excess estrogen, and central venous line placement) were compared between patients with and without PE using univariate statistics, including Student t test and Pearson chi-square test. Multiple logistic regression modeling was used to identify independent risk factors for PE. Receiver operating characteristic curve analysis was applied to determine the optimal cutoff number of risk factors for predicting a pulmonary CTA result positive for PE. RESULTS: The study population consisted of 116 patients (34 men and 82 women; mean age, 20.7 ± 1.8 years; range, 18.6-25.4 years) who underwent a total of 116 pulmonary CTA studies. Sixteen (14%) of 116 patients were found to have PE on pulmonary CTA. The level of involvement of PE was segmental in 16 of 31 PEs (52%), lobar in eight (26%), subsegmental in five (16%), and main or central in two (6%). Three risk factors--immobilization (p < 0.001), history of prior PE or DVT (p = 0.001), and cardiac disease (p = 0.004)--were found to be significant independent risk factors for the presence of PE detected by pulmonary CTA. When two or more risk factors were used as the clinical threshold, the sensitivity for positive PE was 75% (12/16 patients) and the specificity was 99% (99/100 patients). CONCLUSION: The use of risk factor assessment as a first-line triage tool has the potential to guide more appropriate use of pulmonary CTA in this population, with potential associated reductions in radiation exposure and costs.

Quality initiatives: lean approach to improving performance and efficiency in a radiology department.

Many hospital radiology departments are adopting "lean" methods developed in automobile manufacturing to improve operational efficiency, eliminate waste, and optimize the value of their services. The lean approach, which emphasizes process analysis, has particular relevance to radiology departments, which depend on a smooth flow of patients and uninterrupted equipment function for efficient operation. However, the application of lean methods to isolated problems is not likely to improve overall efficiency or to produce a sustained improvement. Instead, the authors recommend a gradual but continuous and comprehensive "lean transformation" of work philosophy and workplace culture. Fundamental principles that must consistently be put into action to achieve such a transformation include equal involvement of and equal respect for all staff members, elimination of waste, standardization of work processes, improvement of flow in all processes, use of visual cues to communicate and inform, and use of specific tools to perform targeted data collection and analysis and to implement and guide change. Many categories of lean tools are available to facilitate these tasks: value stream mapping for visualizing the current state of a process and identifying activities that add no value; root cause analysis for determining the fundamental cause of a problem; team charters for planning, guiding, and communicating about change in a specific process; management dashboards for monitoring real-time developments; and a balanced scorecard for strategic oversight and planning in the areas of finance, customer service, internal operations, and staff development.

An official American Thoracic Society/Society of Thoracic Radiology clinical practice guideline: evaluation of suspected pulmonary embolism in pregnancy.

BACKGROUND: Pulmonary embolism (PE) is a leading cause of maternal mortality in the developed world. Along with appropriate prophylaxis and therapy, prevention of death from PE in pregnancy requires a high index of clinical suspicion followed by a timely and accurate diagnostic approach. METHODS: To provide guidance on this important health issue, a multidisciplinary panel of major medical stakeholders was convened to develop evidence-based guidelines for evaluation of suspected pulmonary embolism in pregnancy using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) system. In formulation of the recommended diagnostic algorithm, the important outcomes were defined to be diagnostic accuracy and diagnostic yield; the panel placed a high value on minimizing cumulative radiation dose when determining the recommended sequence of tests. RESULTS: Overall, the quality of the underlying evidence for all recommendations was rated as very low or low, with some of the evidence considered for recommendations extrapolated from studies of the general population. Despite the low-quality evidence, strong recommendations were made for three specific scenarios: performance of chest radiography (CXR) as the first radiation-associated procedure; use of lung scintigraphy as the preferred test in the setting of a normal CXR; and performance of computed-tomographic pulmonary angiography (CTPA) rather than digital subtraction angiography (DSA) in a pregnant woman with a nondiagnostic ventilation-perfusion (V/Q) result. DISCUSSION: The recommendations presented in this guideline are based upon the currently available evidence; availability of new clinical research data and development and dissemination of new technologies will necessitate a revision and update.

Female breast, lung, and pelvic organ radiation from dose-reduced 64-MDCT thoracic examination protocols: a phantom study.

OBJECTIVE: We compared phantom organ doses delivered to breast, lung, and pelvis by five protocols using current dose reduction methods for routine chest CT and pulmonary CT angiography. MATERIALS AND METHODS: We measured the radiation dose to an anthropomorphic phantom using 64-MDCT with metal oxide semiconductor field effect transistor (MOSFET) detectors in the breast (skin and parenchyma), the lungs, and the pelvis (upper and lower). We compared the following five protocols: protocol 1, 120 kVp, automatic dose modulation, 120-320 mA; protocol 2, 120 kVp, automatic dose modulation, 60-200 mA; protocol 3, 100 kVp and fixed dose of 200 mA; protocol 4, 120 kVp, automatic dose modulation, 200-394 mA; and protocol 5, 80 kVp and fixed dose of 120 mA. Organ doses in milligrays and as a percentage of the volume CT dose index (CTDI(vol)) were compared using the analysis of variance for repeated measurements. RESULTS: Protocol 1 delivered the highest breast dose (mean ± SD, 15.8 ± 1.8 mGy; 110.5% of CTDI(vol)). A decrease in breast radiation of more than 50% was achieved with protocol 3 (4.8 ± 1.8 mGy; 91.7% of CTDI(vol)) compared with protocol 4 (13.1 ± 5.5 mGy; 87.0% of CTDI(vol)) (p = 0.003). The lung received the highest organ dose regardless of the protocol (protocol 4: 21.5 ± 1.7 mGy; 142.5% of CTDI(vol)). Pelvic radiation was low regardless of protocol and did not exceed 0.2 mGy (up to 3.7% of CTDI(vol); p = 0.118-0.999). CONCLUSION: The results of this anthropomorphic phantom study showed substantial and significant variation in radiation doses to the breast and lungs depending on the scanning protocol used with the potential for over threefold dose reduction.

Pulmonary MDCT angiography: value of multiplanar reformatted images in detecting pulmonary embolism in children.

OBJECTIVE: The purpose of this study was to determine whether the use of multiplanar reformatted (MPR) MDCT images in the diagnosis of pulmonary embolism (PE) in children by faculty pediatric radiologists and radiology residents affects reader performance parameters and adds diagnostic value compared with the use of axial MDCT images alone. MATERIALS AND METHODS: This retrospective study was conducted with the images of 60 children (28 boys, 32 girls; mean age, 14.7 ± 3.5 years; range, 3.2-18 years) who consecutively underwent pulmonary CT angiography (CTA) for clinically suspected PE. Two faculty pediatric radiologists and two radiology residents independently reviewed images from each study initially using only axial MDCT images and later using MPR MDCT images in any x-, y-, or z-axis. Diagnostic accuracy, confidence level (1-5 ordinal scale), and interpretation time for MPR MDCT images were compared with those for axial MDCT images by use of the McNemar test and paired Student t test. The kappa coefficient was calculated to assess interobserver agreement. Diagnostic accuracy was compared between faculty pediatric radiologists and radiology residents by logistic regression analysis, and confidence level, interpretation time, and added diagnostic value were evaluated by analysis of variance. RESULTS: Nine of 60 pulmonary CTA studies (15%) were found to show PE. Diagnostic accuracy in detection of PE ranged from 91.7% to 100% (mean, 96.7%) with no significant differences between axial and MPR MDCT images (McNemar test for matched binary pairs, p > 0.50 for each reviewer). Logistic regression showed no significant difference between faculty pediatric radiologists and radiology residents in diagnostic accuracy in detection of PE on axial MDCT images (p = 0.48) or MPR MDCT images (p = 0.24). Confidence level and interobserver agreement were significantly higher and average interpretation time was longer in the evaluation of PE with MPR MDCT images than with axial MDCT images for all reviewers (p < 0.001). Compared with faculty pediatric radiologists, radiology residents had significantly greater increases in confidence level, interobserver agreement, interpretation time, and added diagnostic value using MPR MDCT images than they did using axial MDCT images to diagnose PE (p < 0.001). CONCLUSION: Use of MPR MDCT images for pulmonary CTA in the diagnosis of PE in children significantly increases confidence, interobserver agreement, and interpretation time among faculty pediatric radiologists and radiology residents. Because use of MPR MDCT images results in significantly greater improvements in reading parameters for residents than for faculty members, the routine use of this technique by trainees should be encouraged.

Preoperative MDCT evaluation of congenital lung anomalies in children: comparison of axial, multiplanar, and 3D images.

OBJECTIVE: The objective of our study was to compare the preoperative diagnostic accuracy of axial, multiplanar, and 3D MDCT images for evaluating congenital lung anomalies in pediatric patients and to assess the potential added diagnostic value of multiplanar and 3D MDCT images in this setting. MATERIALS AND METHODS: We used our hospital information system to identify all consecutive pediatric patients younger than 18 years who had undergone preoperative MDCT angiography and had a pathologically proven congenital lung anomaly between June 2005 and February 2010. Each MDCT examination was reviewed independently by two experienced pediatric radiologists for the types, location, associated mass effect, and associated anomalous vessels of congenital lung anomalies on axial, multiplanar, and 3D MDCT images. The final diagnosis was determined by surgical and pathologic findings. Diagnostic accuracy, confidence level of diagnosis (scale of 1-3: 1 = highest confidence and 3 = lowest), perceived added diagnostic value of multiplanar or 3D MDCT images (scale of 1-5: 5 = highest added diagnostic value and 1 = lowest), and interobserver kappa agreement were evaluated. RESULTS: The final study cohort consisted of 46 pediatric patients (28 males and 18 females; mean age, 5.6 ± 6 [SD] months; range, 1 day-50 months). Histopathologic diagnoses included congenital pulmonary airway malformation (n = 19, 41%), sequestration (n = 15, 33%), congenital lobar emphysema (n = 7, 15%), and bronchogenic cyst (n = 5, 11%). Both independent reviewers correctly diagnosed types, location, associated mass effect, and associated anomalous arteries of all congenital lung anomalies with high accuracy (100%) and confidence level (mean confidence level < 1.2) on each type of image display (axial, multiplanar, and 3D). However, for the detection of anomalous veins, multiplanar and 3D images were associated with greater diagnostic accuracy and higher confidence level than axial images alone. Specifically, diagnostic accuracy for the detection of anomalous veins (n = 15; 33%) was 60% (9/15 cases) for axial MDCT images, 80% (12/15) for multiplanar MDCT images, and 100% (15/15) for 3D MDCT images (Friedman test, p = 0.011). Confidence levels for the detection of anomalous veins were significantly higher with 3D MDCT images (mean level = 1.0) and multiplanar MDCT images (mean level = 1.5) compared with axial MDCT images alone (mean level = 2.6) (Friedman test, p < 0.01). Both multiplanar and 3D MDCT images were found to provide added diagnostic value for accurately detecting anomalous veins associated with congenial lung anomalies (paired Student t tests, p < 0.012). CONCLUSION: Axial MDCT images allow accurate diagnosis of the types, location, associated mass effect, and anomalous arteries of congenital lung anomalies, but supplemental multiplanar and 3D MDCT images add diagnostic value for the evaluation of congenital lung lesions associated with anomalous veins.