Evaluation of the Pulmonary Arteries on CTPA With Dual Energy CT: Objective Analysis and Subjective Preferences in a Multireader Study.

PURPOSE: To perform qualitative and quantitative evaluation of low-monoenergetic images (50 KeV) compared with conventional images (120 kVp) in pulmonary embolism (PE) studies and to determine the extent and clinical relevance of these differences as well as radiologists' preferences. MATERIALS AND METHODS: One hundred fifty CT examinations for PE detection conducted on a single-source dual-energy CT were retrospectively evaluated. Attenuation, contrast-to-noise-ratio, and signal-to-noise-ratio were obtained in a total of 8 individual pulmonary arteries on each exam-including both central (450/1200=37.5%) and peripheral (750/1200=62.5%) locations. Results were compared between the conventional and low-monoenergetic images. For quality assessment, 41 images containing PE were presented side-by-side as pairs of slices in both conventional and monoenergetic modes and evaluated for ease in embolus detection by 9 radiologists: cardiothoracic specialists (3), noncardiothoracic specialists (3), and residents (3). Paired samples t tests, a-parametric Wilcoxon test, McNemar test, and kappa statistics were performed. RESULTS: Monoenergetic images had an overall statistically significant increased average ratio of 2.09 to 2.26 (P<0.05) for each measured vessel attenuation, with an increase in signal-to-noise ratio (23.82±9.29 vs. 11.39±3.2) and contrast-to-noise ratio (17.17±6.7 vs 7.27±2.52) (P<0.05). Moreover, 10/150 (6%) of central pulmonary artery measurements considered suboptimal on conventional mode were considered diagnostic on the monoenergetic images (181±14.6 vs. 387.7±72.4 HU respectively, P<0.05). In the subjective evaluation, noncardiothoracic radiologists showed a preference towards low-monoenergetic images, whereas cardiothoracic radiologists did not (74.4% vs. 57.7%, respectively, P<0.05). CONCLUSIONS: The SNR and CNR increase on monoenergetic images may have clinical significance particularly in the setting of sub-optimal PE studies. Noncardiothoracic radiologists and residents prefer low monoenergetic images.

Clinical decision support system recommendations: how often do radiologists and clinicians accept them?

OBJECTIVE: To assess the acceptance and reliability of clinical decision support system (CDSS) imaging referral scores (ESR iGuide). METHODS: A pilot study was conducted in a tertiary hospital. Four different experts were invited to rate 40 simulated clinical cases on a 5-level scale, for the level of agreement with the ESR iGuide's recommended procedures. In cases of disagreement, physicians were asked to indicate the reason. Descriptive measures were calculated for the level of agreement. We also explored the degree of agreement between four different specialists, and examined the cases in which clinicians disagreed with ESR iGuide best practice recommendations. RESULTS: The mean rating of the four experts for the 40 clinical simulated cases was 4.17 ± 0.65, median 4.25 (on a scale of 1-5). All four raters totally agreed with the system recommendation in 75% of cases. No significant relationship was found between the degree of agreement and the number of indications and the patient's age or gender. In an optimistic scenario, using a binary agree/disagree variable, the Overall Percentage Agreement for the rating of the 40 simulated cases between the four experts was 77.28%. There were a total of 20 disagreements out of 160 cases with the ESR iGuide, of which 7 were among the two radiologists. CONCLUSIONS: CDSS can be an effective tool for guiding the selection of appropriate imaging examinations, thus cutting costs due to unnecessary imaging scans. Since this is a pilot study, further research on a larger scale, preferably at national level, is required. KEY POINTS: • The average of the mean rating of the four experts was 4.17 ± 0.65, median 4.25, on a scale of 1-5 where 5 represents total agreement with the CDSS tool. • In an optimistic scenario, using a binary agree/disagree variable, the Overall Percentage Agreement between the four experts was 77.28%. • Radiologists had fewer disagreements with the recommendations of the CDSS tool than other physicians, indicating a better fit of the support system to radiology experts' perspective.

Correlation between coronary artery calcification by non-cardiac CT and Framingham score in young patients.

BACKGROUND: Previous studies have established a correlation between coronary artery calcification (CAC) measured by ECG-gated chest computed tomography (CT) and cardiovascular disease. Recent reports which included asymptomatic patients suggest that CAC measured on non-ECG gated CT is similarly associated with cardiovascular risk. This study investigates the correlation between the Framingham Risk Score (FRS) and an incidental finding of CAC on a non-gated chest CT performed for non-cardiac indications in young and seemingly healthy adults. METHODS: A cross-sectional study that included 162 CT scans performed in young patients aged 18-50 years old for non-cardiac indications in our institution was conducted. CAC score (CACS) was calculated using the Agatston method. FRS was calculated and compared to the CACS using three different approaches. The correlations between the CACS and several specific factors (i.e. age, body mass index, smoking, statins, etc.), were also evaluated. RESULTS: Mean age of patients was 36.43 year old and 105 (64.8%) were male. We found a significant positive correlation between the CACS and the FRS in all three approaches (p<0.05). Increased age, smoking and statin use were the only individual factors clearly associated with an increase in CACS (p = 0.002, p = 0.045 and p = 0.009, respectively). CONCLUSION: This is the first report indicating that incidental CACS identified in non-gated MDCT is also associated with cardiovascular risk evaluated by FRS in a young population. Our findings suggest that young asymptomatic individuals with incidental CAC should be seriously evaluated for cardiovascular risk factors despite presumption of belonging to a low cardiovascular risk category.

Exacerbation of pulmonary sarcoidosis after liver transplantation.

Patients with hepatic sarcoidosis rarely require orthotopic liver transplantation (OLT). Progression of granulomatous activity involving other organs after OLT has rarely been described. We describe a 32-year-old woman who underwent liver transplantation for sarcoidosis-associated end-stage liver disease. She presented 4 years later with shortness of breath, hilar lymphadenopathy, and interstitial lung abnormalities. Liver functions were normal. Open lung biopsy results revealed granulomata compatible with sarcoidosis. The patient made a complete recovery after corticosteroid treatment. To the best of our knowledge, this is a first description of severe exacerbation of pulmonary sarcoidosis in an immunosuppressed patient who underwent liver transplantation for sarcoidosis-associated liver disease.