These guidelines update the previous EANM 2009 guidelines on the diagnosis of pulmonary embolism (PE). Relevant new aspects are related to (a) quantification of PE and other ventilation/perfusion defects; (b) follow-up of patients with PE; (c) chronic PE; and (d) description of additional pulmonary physiological changes leading to diagnoses of left ventricular heart failure (HF), chronic obstructive pulmonary disease (COPD) and pneumonia. The diagnosis of PE should be reported when a mismatch of one segment or two subsegments is found. For ventilation, Technegas or krypton gas is preferred over diethylene triamine pentaacetic acid (DTPA) in patients with COPD. Tomographic imaging with V/PSPECT has higher sensitivity and specificity for PE compared with planar imaging. Absence of contraindications makes V/PSPECT an essential method for the diagnosis of PE. When V/PSPECT is combined with a low-dose CT, the specificity of the test can be further improved, especially in patients with other lung diseases. Pitfalls in V/PSPECT interpretation are discussed. In conclusion, V/PSPECT is strongly recommended as it accurately establishes the diagnosis of PE even in the presence of diseases like COPD, HF and pneumonia and has no contraindications.

• 91% of all lung nodules were detected with ultralow dose CT • Sensitivity for subsolid nodule detection is lower in ultralow dose CT (77.5%) • The mean effective radiation dose in 202 patients was 0.13 mSv • Ultralow dose CT seems to be feasible for lung cancer screening.

Iterative reconstruction reduces image noise and blooming artifacts from calcifications, leading to improved diagnostic accuracy of coronary CT angiography in patients with heavily calcified coronary arteries.

Purpose To evaluate whether a dual-energy (DE) computed tomographic (CT) virtual noncalcium technique can improve the detection rate of acute thoracolumbar vertebral compression fractures in patients with osteoporosis compared with that at magnetic resonance (MR) imaging depending on the level of experience of the reading radiologist. Materials and Methods This retrospective study was approved by the institutional ethics committee. Informed consent was obtained from all patients. Forty-nine patients with osteoporosis who were suspected of having acute vertebral fracture underwent DE CT and MR imaging. Conventional linear-blended CT scans and corresponding virtual noncalcium reconstructions were obtained. Five radiologists with varying levels of experience evaluated gray-scale CT scans for the presence of fractures and their suspected age. Then, virtual noncalcium images were evaluated to detect bone marrow edema. Findings were compared with those from MR imaging (the standard of reference). Sensitivity and specificity analyses for diagnostic performance and matched pair analyses were performed on vertebral fracture and patient levels. Results Sixty-two fractures were classified as fresh and 52 as old at MR imaging. The diagnostic performance of all readers in the detection of fresh fractures improved with the addition of virtual noncalcium reconstructions compared with that with conventional CT alone. Although the diagnostic accuracy of the least experienced reader with virtual noncalcium CT (accuracy with CT alone, 61%; accuracy with virtual noncalcium technique, 83%) was within the range of that of the most experienced reader with CT alone, the latter improved his accuracy with the noncalcium technique (from 81% to 95%), coming close to that with MR imaging. The number of vertebrae rated as unclear decreased by 59%-90% or from 15-53 to 2-13 in absolute numbers across readers. The number of patients potentially referred to MR imaging decreased by 36%-87% (from 11-23 to 2-10 patients). Considering the gain in true decisions with the virtual noncalcium technique on a patient level, between 12 (most experienced reader) and 17 (least experienced reader) MR examinations could have been avoided. Conclusion The DE CT-based virtual noncalcium technique may enable depiction of bone marrow edema in thoracolumbar vertebral compression fractures in patients with osteoporosis, with good accordance with MR imaging when images are read by experienced radiologists. Although less experienced readers improved their diagnostic performance to some degree, the experienced reader's diagnostic performance approached that with MR imaging. (©) RSNA, 2016.

No abstract

• Mono + DECT combines increased contrast with reduced image noise, unlike linearly blended images. • Mono + DECT imaging allows for superior CNR and subjective image quality. • Head and neck tumour contrast-to-noise ratio peaks at 40 keV. • 55 keV images are preferred over all other series by observers.

Pulmonary blood volume on DECT in acute PE correlates with RHS and appears to be a predictor of patient outcome in this pilot study.

• Mono+ combines increased attenuation with reduced image noise compared to standard DE-CTA. • Mono+ shows superior contrast-to-noise ratios at low keV compared to linearly-blended images. • Contrast-to-noise ratio in monoenergetic DE-CTA peaks at 40 keV. • Mono+ reconstructions significantly improve quantitative image quality at low keV levels.