A web based Foundations of Radiological Physics for diagnostic radiology residents.

UNLABELLED: RATIONALE AND OBJECTS: We describe a new web-based physics course for radiology residents preparing for the Exam of the Future (EOF). MATERIALS AND METHODS: A course was developed with a total of 12 web-based modules. Six modules were focused on "imaging" and six on "radiation." A module was subdivided into nine short "nuggets." Traditional lectures were replaced by modules using prerecorded lectures (Tegrity) to a secure website (WebCT). Each module was accompanied by three quizzes, each consisting of ten questions designed to reinforce covered materials. All online modules were accompanied by a noon conference that employed an Audience Response System (Turning Point). Seventeen first-year residents over 2 consecutive years beginning in July 2010 took this new course, and participated in an anonymous online follow-up survey (Survey Monkey). RESULTS: The recorded 12 modules had an overall average duration of 72 ± 19 minutes. Ten of 17 residents expressed a preference of 15 minutes for nugget duration. Highest personal assessment scores of each resident's understanding were obtained in human radiation risks and radiation protection. Residents considered supplemental noon conferences to be important for learning radiological physics. Satisfaction level was largely positive, with five residents highly satisfied, nine residents somewhat satisfied, two residents neutral, and only one resident somewhat dissatisfied. CONCLUSIONS: Our Foundations of Radiological Physics course was well received and served as the springboard for mastering x-ray-based imaging modalities of radiography, mammography, fluoroscopy, interventional radiology, and computed tomography.

Pulmonary nocardiosis: computed tomography features at diagnosis.

PURPOSE: To review the computed tomography (CT) imaging features of pulmonary nocardiosis (PN) at the time of initial presentation. MATERIALS AND METHODS: All patients from 1991 to 2008 with PN were identified (n=105). Patients without CT scan available at initial presentation were excluded (n=52). For the remaining 53 patients, standardized radiographic features were recorded. The patients were grouped by predisposing condition. Analysis includes descriptive summary statistics as well as associations among radiographic findings, associated findings, and host characteristics. Parametric and nonparametric statistical methods were used. RESULTS: Median age of the patients was 52 years (range, 6 to 82 y). Some form of immunosuppression was present in 83% of the cases. Preexisting structural abnormalities of the lung were uncommon (bronchiectasis, 7; chronic obstructive pulmonary disease, 3). Twenty (38%) patients had interstitial opacities. Airspace disease was seen in 34 (64%) cases. Thirty (57%) cases revealed discrete nodules, 25 patients had 1 to 6 nodules (mean, 2), and 5 patients had fewer than 6 nodules, with the mean size of the largest nodule being 1.67 cm. Masses were seen in 11 patients (21%), 9 of whom had concomitant nodules. Cavitary lesions, including nodules, masses, or airspace disease, occurred in 40% of the cohort. Mediastinal lymphadenopathy was present in 8 (15%) patients. Fifteen patients (28%) had pleural effusions; the effusions were unilateral in 10 patients. Analysis of radiographic associations with patient groups found discrete nodules to be more often associated with immunosuppression compared with the nonimmunosuppressed group (66% vs. 11%; P=0.0067). CONCLUSION: The CT presentation of PN is heterogeneous. Airspace disease appeared most frequently (in 64% of the cases), and nodules were present in 57% of the cases. Nocardiosis should be considered in the differential diagnosis of immunosuppressed patients with new nodules or masses.

Computer-aided detection of pulmonary embolism at CT pulmonary angiography: can it improve performance of inexperienced readers?

PURPOSE: To evaluate the effect of a computer-aided detection (CAD) algorithm on the performance of novice readers for detection of pulmonary embolism (PE) at CT pulmonary angiography (CTPA). MATERIALS AND METHODS: We included CTPA examinations of 79 patients (50 female, 52 ± 18 years). Studies were evaluated by two independent inexperienced readers who marked all vessels containing PE. After 3 months all studies were reevaluated by the same two readers, this time aided by CAD prototype. A consensus read by three expert radiologists served as the reference standard. Statistical analysis used χ(2) and McNemar testing. RESULTS: Expert consensus revealed 119 PEs in 32 studies. For PE detection, the sensitivity of CAD alone was 78%. Inexperienced readers' initial interpretations had an average per-PE sensitivity of 50%, which improved to 71% (p < 0.001) with CAD as a second reader. False positives increased from 0.18 to 0.25 per study (p = 0.03). Per-study, the readers initially detected 27/32 positive studies (84%); with CAD this number increased to 29.5 studies (92%; p = 0.125). CONCLUSION: Our results suggest that CAD significantly improves the sensitivity of PE detection for inexperienced readers with a small but appreciable increase in the rate of false positives.

Reproducibility of automated noncalcified coronary artery plaque burden assessment at coronary CT angiography.

PURPOSE: To evaluate the accuracy and effect on interreader reproducibility of automated versus manual volumetric quantification of noncalcified coronary artery plaque burden at coronary computed tomography angiography. MATERIALS AND METHODS: Thirty-seven patients underwent 64-slice coronary computed tomography angiography. Two experienced observers in consensus evaluated each study and identified 40 noncalcified coronary artery plaques. Also in consensus, they performed manual, 3-dimensional planimetric measurements on each plaque as the reference standard. The same 2 observers then performed volumetric measurements on each plaque using a threshold-based automated volumetry automated plaque analysis algorithm. Two different, less experienced observers also performed both, manual and automated measurements of each plaque, first independently and then in consensus. Spearman rank correlation was used to determine association between variables. RESULTS: Automated volumetry was successfully performed on each plaque. There was excellent (R=0.920) correlation between the expert manual measurements (average plaque burden=33.58 mm(3)+/-18.16) and automated plaque volumetry (35.64 mm(3)+/-16.42). For the less experienced observers, there was better correlation with expert manual measurements using automated plaque volumetry (R=0.885) than with manual measurements (R=0.854). Interreader correlation for volume measurements by the 2 less experienced observers without and with use of the automated plaque analysis algorithm significantly (P<0.001) increased from R=0.781 to R=0.919. CONCLUSIONS: Compared with expert manual measurements, automated plaque volumetry enables accurate quantification of noncalcified plaque burden. Reproducibility of plaque measurements between different observers is improved. Use of such automated plaque analysis algorithms should facilitate fast, objective and reproducible assessment of noncalcified plaque burden for risk stratification and therapeutic monitoring.