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Objectives: To compare diagnostic accuracy of a deep learning artificial intelligence (AI) for cervical spine (C-spine) fracture detection on CT to attending radiologists and assess which undetected fractures were injuries in need of stabilising therapy (IST). Methods: This single-centre, retrospective diagnostic accuracy study included consecutive patients (age ≥18 years; 2007–2014) screened for C-spine fractures with CT. To validate ground truth, one radiologist and three neurosurgeons independently examined scans positive for fracture. Negative scans were followed up until 2022 through patient files and two radiologists reviewed negative scans that were flagged positive by AI. The neurosurgeons determined which fractures were ISTs. Diagnostic accuracy of AI and attending radiologists (index tests) were compared using McNemar. Results: Of the 2368 scans (median age, 48, interquartile range 30–65; 1441 men) analysed, 221 (9.3%) scans contained C-spine fractures with 133 IST. AI detected 158/221 scans with fractures (sensitivity 71.5%, 95% CI 65.5–77.4%) and 2118/2147 scans without fractures (specificity 98.6%, 95% CI 98.2–99.1). In comparison, attending radiologists detected 195/221 scans with fractures (sensitivity 88.2%, 95% CI 84.0–92.5%, p < 0.001) and 2130/2147 scans without fracture (specificity 99.2%, 95% CI 98.8–99.6, p = 0.07). Of the fractures undetected by AI 30/63 were ISTs versus 4/26 for radiologists. AI detected 22/26 fractures undetected by the radiologists, including 3/4 undetected ISTs. Conclusion: Compared to attending radiologists, the artificial intelligence has a lower sensitivity and a higher miss rate of fractures in need of stabilising therapy; however, it detected most fractures undetected by the radiologists, including fractures in need of stabilising therapy. Clinical relevance statement The artificial intelligence algorithm missed more cervical spine fractures on CT than attending radiologists, but detected 84.6% of fractures undetected by radiologists, including fractures in need of stabilising therapy. Key Points: The impact of artificial intelligence for cervical spine fracture detection on CT on fracture management is unknown. The algorithm detected less fractures than attending radiologists, but detected most fractures undetected by the radiologists including almost all in need of stabilising therapy. The artificial intelligence algorithm shows potential as a concurrent reader. [ABSTRACT FROM AUTHOR]

Objectives: To compare clinical image quality and perceived impact on diagnostic interpretation of chest CT findings between ultra-high-resolution photon-counting CT (UHR-PCCT) and conventional high-resolution energy-integrating-detector CT (HR-EIDCT) using visual grading analysis (VGA) scores. Materials and methods: Fifty patients who underwent a UHR-PCCT (matrix 512 × 512, 768 × 768, or 1024 × 1024; FOV average 275 × 376 mm, 120 × 0.2 mm; focal spot size 0.6 × 0.7 mm) between November 2021 and February 2022 and with a previous HR-EIDCT within the last 14 months were included. Four readers evaluated central and peripheral airways, lung vasculature, nodules, ground glass opacities, inter- and intralobular lines, emphysema, fissures, bullae/cysts, and air trapping on PCCT (0.4 mm) and conventional EIDCT (1 mm) via side-by-side reference scoring using a 5-point diagnostic quality score. The median VGA scores were compared and tested using one-sample Wilcoxon signed rank tests with hypothesized median values of 0 (same visibility) and 2 (better visibility on PCCT with impact on diagnostic interpretation) at a 2.5% significance level. Results: Almost all lung structures had significantly better visibility on PCCT compared to EIDCT (p < 0.025; exception for ground glass nodules (N = 2/50 patients, p = 0.157)), with the highest scores seen for peripheral airways, micronodules, inter- and intralobular lines, and centrilobular emphysema (mean VGA > 1). Although better visibility, a perceived difference in diagnostic interpretation could not be demonstrated, since the median VGA was significantly different from 2. Conclusion: UHR-PCCT showed superior visibility compared to HR-EIDCT for central and peripheral airways, lung vasculature, fissures, ground glass opacities, macro- and micronodules, inter- and intralobular lines, paraseptal and centrilobular emphysema, bullae/cysts, and air trapping. Clinical relevance statement: UHR-PCCT has emerged as a promising technique for thoracic imaging, offering improved spatial resolution and lower radiation dose. Implementing PCCT into daily practice may allow better visibility of multiple lung structures and optimization of scan protocols for specific pathology. Key Points: • The aim of this study was to verify if the higher spatial resolution of UHR-PCCT would improve the visibility and detection of certain lung structures and abnormalities. • UHR-PCCT was judged to have superior clinical image quality compared to conventional HR-EIDCT in the evaluation of the lungs. UHR-PCCT showed better visibility for almost all tested lung structures (except for ground glass nodules). • Despite superior image quality, the readers perceived no significant impact on the diagnostic interpretation of the studied lung structures and abnormalities. [ABSTRACT FROM AUTHOR]

Objectives: To determine the accuracy of scoutless, fixed-dose ultra-low-dose (ULD) CT compared to standard-dose (SD) CT for pulmonary nodule detection and semi-automated nodule measurement, across different patient sizes. Methods: Sixty-three patients underwent ULD and SD CT. Two readers examined all studies visually and with computer-aided detection (CAD). Nodules detected on SD CT were included in the reference standard by consensus and stratified into 4 categories (nodule category, NODCAT) from the Dutch-Belgian Lung Cancer Screening trial (NELSON). Effects of NODCAT and patient size on nodule detection were determined. For each nodule, volume and diameter were compared between both scans. Results: The reference standard comprised 173 nodules. For both readers, detection rates on ULD versus SD CT were not significantly different for NODCAT 3 and 4 nodules > 50 mm3 (reader 1: 93% versus 89% (p = 0.257); reader 2: 96% versus 98% (p = 0.317)). For NODCAT 1 and 2 nodules < 50 mm3, detection rates on ULD versus SD CT dropped significantly (reader 1: 66% versus 80% (p = 0.023); reader 2: 77% versus 87% (p = 0.039)). Body mass index and chest circumference did not influence nodule detectability (p = 0.229 and p = 0.362, respectively). Calculated volumes and diameters were smaller on ULD CT (p < 0.0001), without altering NODCAT (84% agreement). Conclusions: Scoutless ULD CT reliably detects solid lung nodules with a clinically relevant volume (> 50 mm3) in lung cancer screening, irrespective of patient size. Since detection rates were lower compared to SD CT for nodules < 50 mm3, its use for lung metastasis detection should be considered on a case-by-case basis. Key Points: • Detection rates of pulmonary nodules > 50 mm3are not significantly different between scoutless ULD and SD CT (i.e. volumes clinically relevant in lung cancer screening based on the NELSON trial), but were different for the detection of nodules < 50 mm3(i.e. volumes still potentially relevant in lung metastasis screening). • Calculated nodule volumes were on average 0.03 mL or 9% smaller on ULD CT, which is below the 20–25% interscan variability previously reported with software-based volumetry. • Even though a scoutless, fixed-dose ULD CT protocol was used (CTDIvol0.15 mGy), pulmonary nodule detection was not influenced by patient size. [ABSTRACT FROM AUTHOR]

Objectives: We sought to evaluate cardiac CT angiography (CCTA)–based assessment of left atrial (LA) function as a predictor of hospitalizations for heart failure (HF) and cardiovascular (CV) mortality. Methods: LA function was evaluated using automatic derivation of LA volumes to calculate LA total emptying fraction (LATEF) in 788 consecutive patients with normal sinus rhythm who had undergone spiral CT scans. The relationship between LATEF evaluated by CCTA and the composite endpoint of admission for HF or CV mortality was analyzed using Cox models. Results: During a median follow-up of 4 years, there were 100 events, 62 HF hospitalizations, and 38 cardiovascular deaths. Mean LATEF was 30.7 ± 10.7% and 40.5 ± 11.2% in patients with and without events, respectively (p < 0.0001). A high LATEF (upper tertile > 46%) was associated with a very low event rate (3.5% at 6 years [95% CI 1.7–7.1%]). The adjusted HR for HF or CV mortality was 4.37 (95% CI 1.99–9.60) in the lowest LATEF tertile, and 2.29 (95% CI 1.03–5.14) in the middle tertile, relative to the highest tertile. For the endpoint of HF alone, adjusted HR for the lowest LATEF tertile was 5.93 (95% CI 2.23–15.82) and for the middle tertile 2.89 (95% CI 1.06–7.86). The association of LATEF with outcome was similar for patients with both reduced and preserved left ventricular (LV) ejection fraction (Pinteraction = 0.724). Reduced LATEF was associated with a high event rate, even when coupled with normal LA volume. Conclusion: CCTA-derived LA function is a predictor of HF hospitalization or CV death, independent of clinical risk factors, LA volume, and LV systolic function. Key Points: • Left atrial function can be automatically derived from cardiac CTA scans. • Cardiac CTA-derived left atrial function is a predictor of hospitalization for heart failure and cardiovascular death. • Evaluation of left atrial function could be useful in identifying patients at risk of heart failure. [ABSTRACT FROM AUTHOR]

Objectives: The failure rate following prostate artery embolization (PAE) is around 20%, which may in part result from inadequate embolization. Prostate contrast retention (PCR) adequacy on immediate post-embolization cone-beam CT may provide better assessment of embolization completeness than arterial contrast stasis seen on fluoroscopy alone. The aim of this study was to evaluate outcomes of PAE using PCR adequacy as the procedural endpoint. Methods: A retrospective cohort study of all PAE cases using this technique at a single large volume center was conducted. Following initial embolization of the main prostatic arteries, if PCR was inadequate, additional embolization was performed. Technical success (adequate PCR) was defined as > 75% global prostate gland contrast staining. Clinical success was determined in accordance to CIRSE standards of practice. Results: One hundred sixty-five patients (mean age 68 ± 8.4 years) underwent PAE from June 2017 to March 2019. Technical and clinical success rates were 98.8% and 96.4% respectively. Clinical success rate was significantly higher in patients with adequate PCR. International Prostate Symptom Scores (IPSS) and Quality of Life (QoL) scores significantly improved at 1-, 3-, 6-, and 12-month follow-up when compared to baseline. Prostate volume (PV) and post-voiding residual bladder volume were significantly reduced at 3, 6, and 12 months in comparison to baseline. Mild (Clavien-Dindo grade I/II) and moderate (grade III) complication rates were 12.1% and 3.6% respectively. Conclusions: By using PCR adequacy as a guide to determine the procedure endpoint for PAE, it may be possible to achieve more complete embolization and thus higher clinical success rates. Key Points: • By using PCR adequacy as a guide to determine the procedure endpoint for PAE, it may be possible to achieve more complete embolization and thus higher clinical success rates. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the association between a sign and visceral pleural invasion (VPI) of peripheral non–small-cell lung cancer (NSCLC) that does not appear touching the pleural surface. Methods: A total of 221 consecutive patients with NSCLC that did not appear touching the pleural surface, ≤ 3 cm in solid tumor diameter, and was surgically resected between January 2009 and December 2015 were included. We focused on the flat distortion of the tumor caused by an arch-shaped linear tag between the tumor and the pleura on CT and named it a bridge tag sign. We evaluated the associations between the clinicopathological features of the tumor, including the bridge tag sign, and VPI. We also evaluated the associations between histopathological findings and the bridge tag sign. The utility of the bridge tag sign in the diagnosis of VPI was statistically assessed. Results: The bridge tag sign was observed in 48 (20.8%) patients. VPI was positive in 9 (4.1%) patients; among these, the bridge tag sign was positive in 8 patients. In multivariate analysis, a bridge tag sign was significantly associated with VPI. The bridge tag sign was associated with longer contact length of the pleura with the tumor and trapezoid type pleural retraction. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the bridge tag sign in the diagnosis of VPI were 88.9%, 83.5%, 83.7%, 18.6%, and 99.4%, respectively. Conclusions: A bridge tag sign on CT might improve the accuracy of the prediction of VPI. Key Points: • We present the bridge tag sign which is defined as a flat distortion of an NSCLC tumor by an arch-shaped linear tag between the tumor and chest wall or interlobar fissure. • The bridge tag sign was an independent predictive factor for visceral pleural invasion. • The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the bridge tag sign in the diagnosis of visceral pleural invasion were 88.9%, 83.5%, 83.7%, 18.6%, and 99.4%, respectively. [ABSTRACT FROM AUTHOR]

Objectives: To investigate whether CT slice thickness influences the performance of radiomics prognostic models in non-small-cell lung cancer (NSCLC) patients.Methods: CT images including 1-, 3-, and 5-mm slice thicknesses acquired from 311 patients who underwent surgical resection for NSCLC between May 2014 and December 2015 were evaluated. Tumor segmentation was performed on CT of each slice thickness and total 94 radiomics features (shape, tumor intensity, and texture) were extracted. The study population was temporally split into development (n = 185) and validation sets (n = 126) for prediction of disease-free survival (DFS). Three radiomics models were built from three different slice thickness datasets (Rad-1, Rad-3, and Rad-5), respectively. Model performance was assessed and compared in three slice thickness datasets and mixed slice thickness dataset using C-indices.Results: In corresponding slice thickness datasets, the C-indices of Rad-1, Rad-3, and Rad-5 for prediction of DFS were 0.68, 0.70, and 0.68 in the development set, and 0.73, 0.73, and 0.76 in the validation set (p = 0.40-0.89 and 0.27-0.90, respectively). Performance of the models was not significantly changed when they were applied to different slice thicknesses data in the validation set (C-index, 0.73-0.76, 0.72-0.73, 0.75-0.76; p = 0.07-0.92). In the mixed slice thickness dataset, performances of the models were similar to or slightly lower than their performances in the corresponding slice thickness datasets (C-index, 0.72-0.75 vs. 0.73-0.76) in the validation set.Conclusions: The performance of radiomics models for predicting DFS in NSCLC patients was not significantly affected by CT slice thickness.Key Points: • Three radiomics models based on 1-, 3-, and 5-mm CT datasets showed C-indices for predicting disease-free survival of 0.68-0.70 in the development set and 0.73-0.76 in the validation set, without statistical differences (p = 0.27-0.90). • Application of the radiomics models to different slice thickness datasets showed no significant differences in performance between the values in the prediction of disease-free survival (p = 0.07-0.99). • Three radiomics models based on 1-, 3-, and 5-mm CT datasets performed well in mixed slice thickness datasets, showing similar or slightly lower performances. [ABSTRACT FROM AUTHOR]

Objective: Comparison of virtual CT enteroscopy (VCTE) using carbon dioxide with small-bowel enteroclysis (SBE) and capsule endoscopy (CE) in small-bowel tuberculosis (SBTB). Methods: This prospective study comprised consecutive patients suspected to have SBTB. VCTE and SBE were performed on the same day and evaluated by independent radiologists. CE was performed within 2 weeks. VCTE was performed following insufflation of carbon dioxide via catheters in the jejunum and anorectum. A contrast-enhanced CT was followed by a delayed non-contrast CT. Image processing was done using virtual colonoscopy software. Findings on VCTE, SBE, and CE were compared. The final diagnosis of SBTB was based on either histopathological or cytological findings, response to antitubercular treatment, or a combination of these. Results: Of the 55 patients in whom VCTE was performed, complete data was available in 52 patients. A final diagnosis of SBTB was established in 37 patients. All patients had VCTE and SBE. CE was performed in 34 patients. Adequate luminal distension was achieved in all patients with SBE and 35 patients with VCTE. SBE showed more strictures in jejunum (10.8%) and ileum (75.7%) compared with VCTE (jejunum, 8.1%, and ileum, 64.9%) and CE (jejunum, 5.9%, and ileum, 61.8%). However, difference was not statistically significant. VCTE revealed a greater length of strictures in both the jejunum and ileum compared with SBE and CE. Conclusion: VCTE allows adequate evaluation of the bowel in most patients with SBTB. It allows detection of greater length of abnormality in jejunum and ileum compared with SBE and CE. Key Points: • The use of VCTE using CO2bowel insufflation in patients with SBTB should be considered. • VCTE allows detection of a greater length of abnormality in the jejunum and ileum. [ABSTRACT FROM AUTHOR]

Objectives: To systematically analyze CT findings during the early and progressive stages of natural course of coronavirus disease 2019 and also to explore possible changes in pulmonary parenchymal abnormalities during these two stages.Methods: We retrospectively reviewed the initial chest CT data of 62 confirmed coronavirus disease 2019 patients (34 men, 28 women; age range 20-91 years old) who did not receive any antiviral treatment between January 21 and February 4, 2020, in Chongqing, China. Patients were assigned to the early-stage group (onset of symptoms within 4 days) or progressive-stage group (onset of symptoms within 4-7 days) for analysis. CT characteristics and the distribution, size, and CT score of pulmonary parenchymal abnormalities were assessed.Results: In our study, the major characteristic of coronavirus disease 2019 was ground-glass opacity (61.3%), followed by ground-glass opacity with consolidation (35.5%), rounded opacities (25.8%), a crazy-paving pattern (25.8%), and an air bronchogram (22.6%). No patient presented cavitation, a reticular pattern, or bronchial wall thickening. The CT scores of the progressive-stage group were significantly greater than those of the early-stage group (p = 0.004).Conclusions: Multiple ground-glass opacities with consolidations in the periphery of the lungs were the primary CT characteristic of coronavirus disease 2019. CT score can be used to evaluate the severity of the disease. If these typical alterations are found, then the differential diagnosis of coronavirus disease 2019 must be considered.Key Points: • Multiple GGOs with consolidations in the periphery of the lungs were the primary CT characteristic of COVID-19. • The halo sign may be a special CT feature in the early-stage COVID-19 patients. • Significantly increased CT score may indicate the aggravation of COVID-19 in the progressive stage. [ABSTRACT FROM AUTHOR]

Purpose: Detection of peritoneal metastases (PM) is key in the staging and management of gastrointestinal and ovarian cancer patients. The purpose of this meta-analysis was to determine the diagnostic performance of CT, PET(CT), and (DW)MRI in detecting PM.Methods: A literature search in Pubmed, Embase (Ovid), and Scopus was performed (January 1997-May 2018) to identify studies reporting on the accuracy of imaging PM in the diagnostic workup of gastrointestinal or ovarian cancers. Inclusion criteria were region-based or patient-based studies comprising > 15 patients, surgery/histology/radiological follow-up as a reference standard, and sufficient data to construct a 2 × 2 contingency table. Two observers performed data extraction. The sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated using a bivariate random-effects model and hierarchical summary operating curves (HSROC) were generated.Results: Of 3457 citations retrieved, twenty-four articles met all inclusion criteria. Thirty-seven datasets could be extracted for analysis including 20 for CT, 10 for PET(CT), and 7 for (DW)MRI. The pooled sensitivity, specificity, and DOR for the detection of PM for region-based studies for CT were 68% (CI, 46-84%), 88%(CI, 81-93%), and 15.9 (CI, 4.4-58.0) respectively; 80% (CI, 57-92%), 90% (CI, 80-96%), and 36.5 (CI, 6.7-199.5) for PET(CT), respectively; 92% (CI, 84-96%), 85% (CI, 78-91%), 63.3 (CI, 31.5-127.3) for (DW)MRI. In the patient-based group, not enough studies were included to make a pooled analysis for (DW)MRI and PET(CT).Conclusion: (DW)MRI and PET(CT) showed comparable diagnostic performance for the detection of peritoneal metastases in ovarian and gastrointestinal cancer patients. Since MRI is more widely available than PET(CT) in clinical practice, this potentially is the imaging method of choice in most centers in the future.Key Points: • Detection of peritoneal metastases plays an important role in the accurate staging of cancer patients, however, there is no accepted reference standard for the imaging of peritoneal metastases • This meta-analysis shows that (DW)MRI provided the highest sensitivity for the detection of peritoneal metastases in ovarian and gastrointestinal cancer patients • Although (DW)MRI and PET(CT) show a comparable overall diagnostic performance, (DW)MRI seems to be the imaging method of choice since it is more available in daily practice than PET(CT). [ABSTRACT FROM AUTHOR]

Purpose: To assess quantitative lobar pulmonary perfusion on DECT-PA in patients with and without pulmonary embolism (PE).Materials and Methods: Our retrospective study included 88 adult patients (mean age 56 ± 19 years; 38 men, 50 women) who underwent DECT-PA (40 PE present; 48 PE absent) on a 384-slice, third-generation, dual-source CT. All DECT-PA examinations were reviewed to record the presence and location of occlusive and non-occlusive PE. Transverse thin (1 mm) DECT images (80/150 kV) were de-identified and exported offline for processing on a stand-alone deep learning-based prototype for automatic lung lobe segmentation and to obtain the mean attenuation numbers (in HU), contrast amount (in mg), and normalized iodine concentration per lung and lobe. The zonal volumes and mean enhancement were obtained from the Lung Analysis™ application. Data were analyzed with receiver operating characteristics (ROC) and analysis of variance (ANOVA).Results: The automatic lung lobe segmentation was accurate in all DECT-PA (88; 100%). Both lobar and zonal perfusions were significantly lower in patients with PE compared with those without PE (p < 0.0001). The mean attenuation numbers, contrast amounts, and normalized iodine concentrations in different lobes were significantly lower in the patients with PE compared with those in the patients without PE (AUC 0.70-0.78; p < 0.0001). Patients with occlusive PE had significantly lower quantitative perfusion compared with those without occlusive PE (p < 0.0001).Conclusion: The deep learning-based prototype enables accurate lung lobe segmentation and assessment of quantitative lobar perfusion from DECT-PA.Key Points: • Deep learning-based prototype enables accurate lung lobe segmentation and assessment of quantitative lobar perfusion from DECT-PA. • Quantitative lobar perfusion parameters (AUC up to 0.78) have a higher predicting presence of PE on DECT-PA examinations compared with the zonal perfusion parameters (AUC up to 0.72). • The lobar-normalized iodine concentration has the highest AUC for both presence of PE and for differentiating occlusive and non-occlusive PE. [ABSTRACT FROM AUTHOR]

Objectives: Chronic obstructive pulmonary disease (COPD) is characterized by variable contributions of emphysema and airway disease on computed tomography (CT), and still little is known on their temporal evolution. We hypothesized that quantitative CT (QCT) is able to detect short-time changes in a cohort of patients with very severe COPD.Methods: Two paired in- and expiratory CT each from 70 patients with avg. GOLD stage of 3.6 (mean age = 66 ± 7.5, mean FEV1/FVC = 35.28 ± 7.75) were taken 3 months apart and analyzed by fully automatic software computing emphysema (emphysema index (EI), mean lung density (MLD)), air-trapping (ratio expiration to inspiration of mean lung attenuation (E/I MLA), relative volume change between - 856 HU and - 950 HU (RVC856-950)), and parametric response mapping (PRM) parameters for each lobe separately and the whole lung. Airway metrics measured were wall thickness (WT) and lumen area (LA) for each airway generation and the whole lung.Results: The average of the emphysema parameters (EI, MLD) increased significantly by 1.5% (p < 0.001) for the whole lung, whereas air-trapping parameters (E/I MLA, RVC856-950) were stable. PRMEmph increased from 34.3 to 35.7% (p < 0.001), whereas PRMNormal decrased from 23.6% to 22.8% (p = 0.012). WT decreased significantly from 1.17 ± 0.18 to 1.14 ± 0.19 mm (p = 0.036) and LA increased significantly from 25.08 ± 4.49 to 25.84 ± 4.87 mm2 (p = 0.041) for the whole lung. The generation-based analysis showed heterogeneous results.Conclusion: QCT detects short-time progression of emphysema in severe COPD. The changes were partly different among lung lobes and airway generations, indicating that QCT is useful to address the heterogeneity of COPD progression.Key Points: • QCT detects short-time progression of emphysema in severe COPD in a 3-month period. • QCT is able to quantify even slight parenchymal changes, which were not detected by spirometry. • QCT is able to address the heterogeneity of COPD, revealing inconsistent changes individual lung lobes and airway generations. [ABSTRACT FROM AUTHOR]

Objective: To assess the diagnostic accuracy of 256-row multislice computed tomographic angiography (CTA) compared with three-dimensional rotational angiography (3DRA) in the postoperative evaluation of cerebral aneurysms treated with titanium clips.Methods: A total of 128 patients (42 men, 86 women; mean age, 57.6 years) with 143 cerebral aneurysms treated using titanium clips underwent both CTA and 3DRA. Two reviewers retrospectively evaluated the following parameters on CTA and 3DRA: (1) residual/recurrent aneurysm (absent or present), (2) patency of parent artery (patent or occluded/severe stenotic (> 70%)), and (3) patency of adjacent branch (patent or occluded/absent).Results: A total of 24 residual/recurrent aneurysms were detected by 3DRA. The sensitivity, specificity, and accuracy of CTA for the detection of residual/recurrent aneurysms were 83.3%, 100%, and 97.2% for reviewer 1 and 79.2%, 100%, and 96.5% for reviewer 2, respectively. The sensitivity, specificity, and accuracy of CTA for the evaluation of patency of parent artery were 100%, 100%, and 100%, respectively, for both reviewers. The sensitivity, specificity, and accuracy of CTA for evaluation of the patency of adjacent branch were 85.1%, 100%, and 92.3% for reviewer 1 and 82.4%, 100%, and 90.9% for reviewer 2, respectively.Conclusion: A 256-row multislice CTA is a valuable non-invasive tool for assessment of cerebral aneurysms treated with titanium clips.Key Points: • A 256-row multislice CTA is an accurate imaging technique for the postoperative assessment of cerebral aneurysms treated with titanium clips. • Sensitivity of CTA for the detection of residual/recurrent aneurysms was 79-83% compared with 3DRA. • CTA is still limited in detecting residual/recurrent aneurysms of < 2 mm and small adjacent branches. [ABSTRACT FROM AUTHOR]

Objectives: Diagnostic performance and potential radiation dose reduction of wide-area detector CT sequential acquisition ("wide-volume" acquisition (WV)) in unenhanced chest examination are unknown. This study aims to assess the image quality, the diagnostic performance, and the radiation dose reduction of WV mode compared with the classical helical acquisition for lung parenchyma analysis in an ultra-low-dose (ULD) protocol.Methods: After Institutional Review Board Approval and written informed consent, 64 patients (72% men; 67.6 ± 9.7 years old; BMI 26.1 ± 5.3 kg/m2) referred for a clinically indicated unenhanced chest CT were prospectively included. All patients underwent, in addition to a standard helical acquisition (120 kV, automatic tube current modulation), two ULD acquisitions (135 kV, fixed tube current at 10 mA): one in helical mode and one in WV mode. Image noise, subjective image quality (5-level Likert scale), and diagnostic performance for the detection of 9 predetermined parenchymal abnormalities were assessed by two radiologists and compared using the chi-square or Fisher non-parametric tests.Results: Subjective image quality (4.2 ± 0.7 versus 4.2 ± 0.8, p = 0.56), image noise (41.7 ± 8 versus 40.9 ± 8.7, p = 0.3), and diagnostic performance were equivalent between ULD WV and ULD helical. Radiation dose was significantly lower for the ULD WV acquisition (mean dose-length product 14.1 ± 1.3 mGy cm versus 15.8 ± 1.3, p < 0.0001).Conclusion: An additional 11% dose reduction is achieved with the WV mode in ULD chest CT with fixed tube current, with equivalent image quality and diagnostic performance when compared with the helical acquisition.Key Points: • Image quality and diagnostic performance of ultra-low-dose unenhanced chest CT are identical between wide-volume mode and the reference helical acquisition. • Wide-volume mode allows an additional radiation dose reduction of 11% (mean dose-length product 14.1 ± 1.3 mGy cm versus 15.8 ± 1.3, p < 0.0001). [ABSTRACT FROM AUTHOR]

Objectives: To longitudinally investigate smoking cessation-related changes of quantitative computed tomography (QCT)-based airway metrics in a group of heavy smokers.Methods: CT scans were acquired in a lung cancer screening population over 4 years at 12-month intervals in 284 long-term ex-smokers (ES), 405 continuously active smokers (CS), and 31 subjects who quitted smoking within 2 years after baseline CT (recent quitters, RQ). Total diameter (TD), lumen area (LA), and wall percentage (WP) of 1st-8th generation airways were computed using airway analysis software. Inter-group comparison was performed using Mann-Whitney U test or Student's t test (two groups), and ANOVA or ANOVA on ranks with Dunn's multiple comparison test (more than two groups), while Fisher's exact test or chi-squared test was used for categorical data. Multiple linear regression was used for multivariable analysis.Results: At any time, TD and LA were significantly higher in ES than CS, for example, in 5th-8th generation airways at baseline with 6.24 mm vs. 5.93 mm (p < 0.001) and 15.23 mm2 vs. 13.51 mm2 (p < 0.001), respectively. RQ showed higher TD (6.15 mm vs. 5.93 mm, n.s.) and significantly higher LA (14.77 mm2 vs. 13.51 mm2, p < 0.001) than CS after 3 years, and after 4 years. In multivariate analyses, smoking status independently predicted TD, LA, and WP at baseline, at 3 years and 4 years (p < 0.01-0.001), with stronger impact than pack years.Conclusions: Bronchial dimensions depend on the smoking status. Smoking-induced airway remodeling can be partially reversible after smoking cessation even in long-term heavy smokers. Therefore, QCT-based airway metrics in clinical trials should consider the current smoking status besides pack years.Key Points: • Airway lumen and diameter are decreased in active smokers compared to ex-smokers, and there is a trend towards increased airway wall thickness in active smokers. • Smoking-related airway changes improve within 2 years after smoking cessation. • Smoking status is an independent predictor of airway dimensions. [ABSTRACT FROM AUTHOR]

Objectives: We sought to investigate the diagnostic performance of coronary CT angiography (cCTA)-derived plaque markers combined with deep machine learning-based fractional flow reserve (CT-FFR) to identify lesion-specific ischemia using invasive FFR as the reference standard.Methods: Eighty-four patients (61 ± 10 years, 65% male) who had undergone cCTA followed by invasive FFR were included in this single-center retrospective, IRB-approved, HIPAA-compliant study. Various plaque markers were derived from cCTA using a semi-automatic software prototype and deep machine learning-based CT-FFR. The discriminatory value of plaque markers and CT-FFR to identify lesion-specific ischemia on a per-vessel basis was evaluated using invasive FFR as the reference standard.Results: One hundred three lesion-containing vessels were investigated. 32/103 lesions were hemodynamically significant by invasive FFR. In a multivariate analysis (adjusted for Framingham risk score), the following markers showed predictive value for lesion-specific ischemia (odds ratio [OR]): lesion length (OR 1.15, p = 0.037), non-calcified plaque volume (OR 1.02, p = 0.007), napkin-ring sign (OR 5.97, p = 0.014), and CT-FFR (OR 0.81, p < 0.0001). A receiver operating characteristics analysis showed the benefit of identifying plaque markers over cCTA stenosis grading alone, with AUCs increasing from 0.61 with ≥ 50% stenosis to 0.83 with addition of plaque markers to detect lesion-specific ischemia. Further incremental benefit was realized with the addition of CT-FFR (AUC 0.93).Conclusion: Coronary CTA-derived plaque markers portend predictive value to identify lesion-specific ischemia when compared to cCTA stenosis grading alone. The addition of CT-FFR to plaque markers shows incremental discriminatory power.Key Points: • Coronary CT angiography (cCTA)-derived quantitative plaque markers of atherosclerosis portend high discriminatory power to identify lesion-specific ischemia. • Coronary CT angiography-derived fractional flow reserve (CT-FFR) shows superior diagnostic performance over cCTA alone in detecting lesion-specific ischemia. • A combination of plaque markers with CT-FFR provides incremental discriminatory value for detecting flow-limiting stenosis. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the effect of a spiral tube on contrast enhancement in the hepatic arterial phase (HAP) of gadoxetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI).Methods: In this retrospective study, we observed 104 patients who underwent dynamic MRI of the liver between October 2017 and December 2017. Three Gd-EOB-DTPA injection protocols were compared: (A) conventional method (undiluted Gd-EOB-DTPA, injection rate 1 ml/s, n = 36); (B) spiral dilution method (1:1 diluted Gd-EOB-DTPA with saline [off-label], injection rate 2 ml/s via spiral tube, n = 38); (C) spiral-flushed method (undiluted Gd-EOB-DTPA, injection rate 1 ml/s via spiral tube, n = 30). We regarded protocol-A as a control. The signal-to-noise ratio (SNR) of the abdominal aorta was calculated using arterial phase images. Image contrast and artefacts were evaluated by two board-certified radiologists, using a four-point scale. Statistical analyses included Dunnett's test, the Kruskal-Wallis test and the Steel test.Results: The SNR of the aorta was significantly higher with protocol-C (25.4 ± 8.8) than protocol-A (20.8 ± 5.4, p = 0.01). There was no significant difference in SNR between protocols A and B (p = 0.47). The contrast score of protocol-C was significantly higher than that of protocol-A (p = 0.0019). There was no significant difference in contrast score between protocols A and B (p = 0.50). There was no significant difference in artefacts among the three protocols (p = 0.96).Conclusions: Use of a spiral tube with a slow injection protocol contributed to improved aortic contrast enhancement in the HAP of GD-EOB-DTPA-enhanced hepatic MRI.Key Points: • Gadoxetic acid shows weaker arterial enhancement at recommended doses, compared with nonspecific gadolinium agents; selection of an appropriate injection protocol is important. • A spiral flow-generating tube improves the transport efficiency of the contrast media, and increases the signal-to-noise ratio of the aorta in hepatic arterial phase. • A spiral flow-generating tube does not contribute to artefact reduction in hepatic arterial phase. [ABSTRACT FROM AUTHOR]

A side-by-side comparison of updated guidelines regarding contrast medium-induced acute kidney injury (CI-AKI) from the Swedish Society of Uroradiology (SSUR) and the European Society of Urogenital Radiology (ESUR) is presented. The major discrepancies include a higher glomerular filtration rate (GFR) threshold as a risk factor for CI-AKI and for discontinuation of metformin by SSUR, i.e., < 45 ml/min versus < 30 ml/min/1.73 m2 by ESUR, when intravenous or intra-arterial contrast media (CM) with second-pass renal exposure is administered. SSUR also continues to recommend consideration of traditional non-renal risk factors such as diabetes and congestive heart failure, while ESUR considers these factors as non-specific for CI-AKI and does not recommend any consideration. Contrary to ESUR, SSUR also recommends discontinuation of NSAID and nephrotoxic medication if possible. Insufficient evidence at the present time motivates the more cautionary attitude taken by SSUR. Furthermore, SSUR expresses GFR thresholds in absolute values in ml/min as recommended by the National Kidney Foundation for drugs excreted by glomerular filtration, while ESUR uses the relative GFR normalised to body surface area in ml/min/1.73 m2. CM dose/GFR ratio thresholds established for coronary angiography/interventions are also applied as recommendations for CM-enhanced CT by SSUR, since SSUR regards coronary procedures as a second-pass renal exposure of CM with no obvious difference in the incidence of AKI compared with IV CM administration. Finally, SSUR recommends reducing the gram-iodine dose/GFR ratio from < 1.0 in patients not at risk to < 0.5 in patients at risk of CI-AKI, while ESUR has no such recommendation. KEY POINTS: • The more cautionary attitude taken by SSUR compared with that of ESUR is motivated by insufficient evidence regarding risk for contrast medium-induced acute kidney injuries (CI-AKI). • SSUR recommends that absolute and not relative GFR should be used when dosing drugs eliminated by the kidneys such as contrast media. • According to SSUR the gram-iodine dose/GFR ratio should be < 0.5 in patients at risk of CI-AKI, while ESUR has no such recommendation. [ABSTRACT FROM AUTHOR]

Objectives: To develop an automated density-based computed tomography (CT) score evaluating high-attenuating lung structural abnormalities in patients with cystic fibrosis (CF).Methods: Seventy adult CF patients were evaluated. The development cohort comprised 17 patients treated with ivacaftor, with 45 pre-therapeutic and follow-up chest CT scans. Another cohort of 53 patients not treated with ivacaftor was used for validation. CT-density scores were calculated using fixed and adapted thresholds based on histogram characteristics, such as the mode and standard deviation. Visual CF-CT score was also calculated. Correlations between the CT scores and forced expiratory volume in 1 s (FEV1% pred), and between their changes over time were assessed.Results: On cross-sectional evaluation, the correlation coefficients between FEV1%pred and the automated scores were slightly lower to that of the visual score in the development and validation cohorts (R = up to -0.68 and -0.61, versus R = -0.72 and R = -0.64, respectively). Conversely, the correlation to FEV1%pred tended to be higher for automated scores (R = up to -0.61) than for visual score (R = -0.49) on longitudinal follow-up. Automated scores based on Mode + 3 SD and Mode +300 HU showed the highest cross-sectional (R = -0.59 to -0.68) and longitudinal (R = -0.51 to -0.61) correlation coefficients to FEV1%pred.Conclusions: The developed CT-density score reliably quantifies high-attenuating lung structural abnormalities in CF.Key Points: • Automated CT score shows moderate to good cross-sectional correlations with FEV 1 %pred . • CT score has potential to be integrated into the standard reporting workflow. [ABSTRACT FROM AUTHOR]

Objectives: The pathogenesis leading to poor functional outcome after aneurysmal subarachnoid haemorrhage (aSAH) is multifactorial and not fully understood. We evaluated a machine learning approach based on easily determinable clinical and CT perfusion (CTP) features in the course of patient admission to predict the functional outcome 6 months after ictus.Methods: Out of 630 consecutive subarachnoid haemorrhage patients (2008-2015), 147 (mean age 54.3, 66.7% women) were retrospectively included (Inclusion: aSAH, admission within 24 h of ictus, CTP within 24 h of admission, documented modified Rankin scale (mRS) grades after 6 months. Exclusion: occlusive therapy before first CTP, previous aSAH, CTP not evaluable). A random forests model with conditional inference trees was optimised and trained on sex, age, World Federation of Neurosurgical Societies (WFNS) and modified Fisher grades, aneurysm in anterior vs. posterior circulation, early external ventricular drainage (EVD), as well as MTT and Tmax maximum, mean, standard deviation (SD), range, 75th quartile and interquartile range to predict dichotomised mRS (≤ 2; > 2). Performance was assessed using the balanced accuracy over the training and validation folds using 20 repeats of 10-fold cross-validation.Results: In the final model, using 200 trees and the synthetic minority oversampling technique, median balanced accuracy was 84.4% (SD 0.7) over the training folds and 70.9% (SD 1.2) over the validation folds. The five most important features were the modified Fisher grade, age, MTT range, WFNS and early EVD.Conclusions: A random forests model trained on easily determinable features in the course of patient admission can predict the functional outcome 6 months after aSAH with considerable accuracy.Key Points: • Features determinable in the course of admission of a patient with aneurysmal subarachnoid haemorrhage (aSAH) can predict the functional outcome 6 months after the occurrence of aSAH. • The top five predictive features were the modified Fisher grade, age, the mean transit time (MTT) range from computed tomography perfusion (CTP), the WFNS grade and the early necessity for an external ventricular drainage (EVD). • The range between the minimum and the maximum MTT may prove to be a valuable biomarker for detrimental functional outcome. [ABSTRACT FROM AUTHOR]

Objectives: Adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) are assumed to be indolent lung adenocarcinoma with excellent prognosis. We aim to identify these lesions from invasive adenocarcinoma (IA) by a radiomics approach.Methods: This retrospective study was approved by institutional review board with a waiver of informed consent. Pathologically confirmed lung adenocarcinomas manifested as lung nodules less than 3 cm were retrospectively identified. In-house software was used to quantitatively extract 60 CT-based radiomics features quantifying nodule's volume, intensity and texture property through manual segmentation. In order to differentiate AIS/MIA from IA, least absolute shrinkage and selection operator (LASSO) logistic regression was used for feature selection and developing radiomics signatures. The predictive performance of the signature was evaluated via receiver operating curve (ROC) and calibration curve, and validated using an independent cohort.Results: 402 eligible patients were included and divided into the primary cohort (n = 207) and the validation cohort (n = 195). Using the primary cohort, we developed a radiomics signature based on five radiomics features. The signature showed good discrimination between MIA/AIS and IA in both the primary and validation cohort, with AUCs of 0.95 (95% CI, 0.91-0.98) and 0.89 (95% CI, 0.84-0.93), respectively. Multivariate logistic analysis revealed that the signature (OR, 13.3; 95% CI, 6.2-28.5; p < 0.001) and gender (OR, 3.5; 95% CI, 1.2-10.9; p = 0.03) were independent predictors of indolent lung adenocarcinoma.Conclusion: The signature based on radiomics features helps to differentiate indolent from invasive lung adenocarcinoma, which might be useful in guiding the intervention choice for patients with pulmonary nodules.Key Points: • Based on radiomics features, a signature is established to differentiate adenocarcinoma in situ and minimally invasive adenocarcinoma from invasive lung adenocarcinoma. [ABSTRACT FROM AUTHOR]

Objectives: To compare the image quality of the lungs between ultra-high-resolution CT (U-HRCT) and conventional area detector CT (AD-CT) images.Methods: Image data of slit phantoms (0.35, 0.30, and 0.15 mm) and 11 cadaveric human lungs were acquired by both U-HRCT and AD-CT devices. U-HRCT images were obtained with three acquisition modes: normal mode (U-HRCTN: 896 channels, 0.5 mm × 80 rows; 512 matrix), super-high-resolution mode (U-HRCTSHR: 1792 channels, 0.25 mm × 160 rows; 1024 matrix), and volume mode (U-HRCTSHR-VOL: non-helical acquisition with U-HRCTSHR). AD-CT images were obtained with the same conditions as U-HRCTN. Three independent observers scored normal anatomical structures (vessels and bronchi), abnormal CT findings (faint nodules, solid nodules, ground-glass opacity, consolidation, emphysema, interlobular septal thickening, intralobular reticular opacities, bronchovascular bundle thickening, bronchiectasis, and honeycombing), noise, artifacts, and overall image quality on a 3-point scale (1 = worst, 2 = equal, 3 = best) compared with U-HRCTN. Noise values were calculated quantitatively.Results: U-HRCT could depict a 0.15-mm slit. Both U-HRCTSHR and U-HRCTSHR-VOL significantly improved visualization of normal anatomical structures and abnormal CT findings, except for intralobular reticular opacities and reduced artifacts, compared with AD-CT (p < 0.014). Visually, U-HRCTSHR-VOL has less noise than U-HRCTSHR and AD-CT (p < 0.00001). Quantitative noise values were significantly higher in the following order: U-HRCTSHR (mean, 30.41), U-HRCTSHR-VOL (26.84), AD-CT (16.03), and U-HRCTN (15.14) (p < 0.0001). U-HRCTSHR and U-HRCTSHR-VOL resulted in significantly higher overall image quality than AD-CT and were almost equal to U-HRCTN (p < 0.0001).Conclusions: Both U-HRCTSHR and U-HRCTSHR-VOL can provide higher image quality than AD-CT, while U-HRCTSHR-VOL was less noisy than U-HRCTSHR.Key Points: • Ultra-high-resolution CT (U-HRCT) can improve spatial resolution. • U-HRCT can reduce streak and dark band artifacts. • U-HRCT can provide higher image quality than conventional area detector CT. • In U-HRCT, the volume mode is less noisy than the super-high-resolution mode. • U-HRCT may provide more detailed information about the lung anatomy and pathology. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to assess the CT findings that characterise haemoptysis in patients with chronic pulmonary aspergillosis (CPA).Methods: We retrospectively identified 120 consecutive patients with CPA (84 men and 36 women, 17-89 years of age, mean age 68.4 years) who had undergone a total of 829 CT examinations between January 2007 and February 2017. In the 11 patients who underwent surgical resection, CT images were compared with the pathological results.Results: The scab-like sign was seen on 142 of the 829 CT scans, specifically, in 87 of the 90 CT scans for haemoptysis and in 55 of the 739 CT scans obtained during therapy evaluation. In 48 of those 55 patients, haemoptysis occurred within 55 days (mean 12.0 days) after the CT scan. In the 687 CT scans with no scab-like sign, there were only three instances of subsequent haemoptysis in the respective patients over the following 6 months. Patients with and without scab-like sign differed significantly in the frequency of haemoptysis occurring after a CT scan (p<0.0001). Pathologically, the scab-like sign corresponded to a fibrinopurulent mass or blood crust.Conclusions: The scab-like sign should be considered as a CT finding indicative of haemoptysis.Key Points: • Haemoptysis is commonly found in patients with CPA. • A CT finding indicative of haemoptysis in CPA patients is described. • Scab-like sign may identify CPA patients at higher risk of haemoptysis. [ABSTRACT FROM AUTHOR]

Objectives: To develop a routinely applicable severity index for the management of acute appendicitis in adults using combined clinical and radiological parameters and retroperitoneal space planes (RSP).Methods: Two hundred consecutive patients with histologically proven acute appendicitis and available presurgical CT scans were analysed retrospectively. Two radiologists assessed all CT scans for morphologic sings of appendicitis and six RSP. Clinical parameters were age, body temperature, C-reactive protein (CRP), white blood cell count, and duration of symptoms. Radiological parameters were appendix diameter and wall thickness, periappendiceal fat stranding and fluid, intraluminal and extraluminal air, thinning of appendiceal wall, caecal wall thickening, appendicolith and abscess formation.Results: One hundred and three patients (51%) had histologically proven complicated appendicitis. Based on three clinical (age ≥52 years, body temperature ≥37.5°C, duration of symptoms ≥48 h) and four computed tomography (CT) findings (appendix diameter ≥14 mm, presence of periappendiceal fluid, extraluminal air, perityphlitic abscess), the APSI was developed using regression coefficients of multivariate logistic regression analyses with a maximum of 10 points. A score of ≥4 points predicted complicated appendicitis with a positive predictive value of 92% and a negative predictive value of 83%. Substantial to excellent interobserver agreement was found for the four radiological parameters of the APSI [intraclass correlation coefficient (ICC), 0.78-0.83]. The RSP evaluation presented no added value for the diagnosis of complicated appendicitis.Conclusions: Using APSI, an accurate and simple prediction of complicated appendicitis in adults was possible. The RSP count was not useful for the diagnosis of complicated appendicitis.Key Points: • Appendicitis severity score provides an accurate and simple prediction of complicated appendicitis • Appendicitis severity score ≥4 accurately predicted complicated appendicitis (PPV 92%;NPV 83%) • Evaluation of retroperitoneal space planes was not useful in diagnosing complicated appendicitis. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate a contiguous helical CT protocol with two different target noise levels in chest/abdomen/pelvis CT.Methods: 41 patients (study group) underwent a helical scan (P1) with two different target noise levels (SDs), SD = 16 for chest and SD = 13 for abdomen/pelvis. Two further protocols were planned but not executed: a single helical scan with only one SD (SD = 13) for the entire scan range (P2), and two separate helical scans overlapping over the liver and same SD settings as for P1 (P3). All DLPs were recorded. Image quality was assessed qualitatively and quantitatively on all scans. The control group consisted of 40 patients, was scanned with protocol P3 and analysed using the same metrics.Results: DLPs (mean/SD) for P1, P2 and P3 were 859.5/392.9, 1040.2/510.5 and 1027.4/469.4, respectively. P1 offered a mean dose reduction of 17.4% compared to P2, and 16.3% compared to P3 (both p < 0.001). There were no differences in image quality between both patient groups (p > 0.3).Conclusion: Contiguous helical scanning of the chest/abdomen/pelvis with variable target noise levels results in approximately 17% dose reduction if compared to a single acquisition with only abdominal dose settings or two separate acquisitions of the chest and abdomen/pelvis.Key Points: • Low dose chest and standard abdomen CTs can be combined. • Variable SD CT scanning allows for radiation dose reduction. • Variable SD CT scanning maintains image quality. [ABSTRACT FROM AUTHOR]

Objectives: To determine how to most accurately predict the chance of spontaneous passage of a ureteral stone using information in the diagnostic non-enhanced computed tomography (NECT) and to create predictive models with smaller stone size intervals than previously possible.Methods: Retrospectively 392 consecutive patients with ureteric stone on NECT were included. Three radiologists independently measured the stone size. Stone location, side, hydronephrosis, CRP, medical expulsion therapy (MET) and all follow-up radiology until stone expulsion or 26 weeks were recorded. Logistic regressions were performed with spontaneous stone passage in 4 weeks and 20 weeks as the dependent variable.Results: The spontaneous passage rate in 20 weeks was 312 out of 392 stones, 98% in 0-2 mm, 98% in 3 mm, 81% in 4 mm, 65% in 5 mm, 33% in 6 mm and 9% in ≥6.5 mm wide stones. The stone size and location predicted spontaneous ureteric stone passage. The side and the grade of hydronephrosis only predicted stone passage in specific subgroups.Conclusion: Spontaneous passage of a ureteral stone can be predicted with high accuracy with the information available in the NECT. We present a prediction method based on stone size and location.Key Points: • Non-enhanced computed tomography can predict the outcome of ureteral stones. • Stone size and location are the most important predictors of spontaneous passage. • Prediction models based on stone width or length and stone location are introduced. • The observed passage rates for stone size in mm-intervals are reported. • Clinicians can make better decisions about treatment. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to assess the efficacy of the renewed dynamic collimator in a third-generation dual source CT (DSCT) scanner and to determine the improvements over the second-generation scanner.Methods: Collimator efficacy is defined as the percentage overranging dose in terms of dose-length product (DLP) that is blocked by the dynamic collimator relative to the total overranging dose in case of a static collimator. Efficacy was assessed at various pitch values and different scan lengths. The number of additional rotations due to overranging and effective scan length were calculated on the basis of reported scanning parameters. On the basis of these values, the efficacy of the collimator was calculated.Results: The second-generation scanner showed decreased performance of the dynamic collimator at increasing pitch. Efficacy dropped to 10% at the highest pitch. For the third-generation scanner the efficacy remained above 50% at higher pitch. Noise was for some pitch values slightly higher at the edge of the imaged volume, indicating a reduced scan range to reduce the overranging dose.Conclusions: The improved dynamic collimator in the third-generation scanner blocks the overranging dose for more than 50% and is more capable of shielding radiation dose, especially in high pitch scan modes.Key Points: • Overranging dose is to a large extent blocked by the dynamic collimator • Efficacy is strongly improved within the third-generation DSCT scanner • Reducing the number of additional rotations can reduce overranging with increased noise. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate image quality and diagnostic accuracy for acute infarct detection and radiation dose of 70 kVp whole brain CT perfusion (CTP) and CT angiography (CTA) reconstructed from CTP source data.Methods: Patients were divided into three groups (n = 50 each): group A, 80 kVp, 21 scanning time points; groups B, 70 kVp, 21 scanning time points; group C, 70 kVp, 17 scanning time points. Objective and subjective image quality of CTP and CTA were compared. Diagnostic accuracy for detecting acute infarct and cerebral artery stenosis ≥ 50 % was calculated for CTP and CTA with diffusion weighted imaging and digital subtraction angiography as reference standards. Effective radiation dose was compared.Results: There were no differences in any perfusion parameter value between three groups (P > 0.05). No difference was found in subjective image quality between three groups (P > 0.05). Diagnostic accuracy for detecting acute infarct and vascular stenosis showed no difference between three groups (P > 0.05). Compared with group A, radiation doses of groups B and C were decreased by 28 % and 37 % (both P < 0.001), respectively.Conclusion: Compared with 80 kVp protocol, 70 kVp brain CTP allows comparable vascular and perfusion assessment and lower radiation dose while maintaining high diagnostic accuracy in detecting acute infarct.Key Points: • 70 kVp whole brain CTP can provide diagnostic image quality. • 70 kVp CTP diagnostic accuracy was maintained vs. 80 kVp protocol. • 70 kVp CTP radiation doses were lower than 80 kVp protocol. [ABSTRACT FROM AUTHOR]

Objectives: To compare a low-tube-voltage with or without high-iodine-load multidetector CT (MDCT) protocol with a normal-tube-voltage, normal-iodine-load (standard) protocol in patients with pancreatic ductal adenocarcinoma (PDAC) with respect to tumour conspicuity and image quality.Methods: Thirty consecutive patients (mean age: 66 years, men/women: 14/16) preoperatively underwent triple-phase 64-channel MDCT examinations twice according to: (i) 120-kV standard protocol (PS; 0.75 g iodine (I)/kg body weight, n = 30) and (ii) 80-kV protocol A (PA; 0.75 g I/kg, n = 14) or protocol B (PB; 1 g I/kg, n = 16). Two independent readers evaluated tumour delineation and image quality blindly for all protocols. A third reader estimated the pancreas-to-tumour contrast-to-noise ratio (CNR). Statistical analysis was performed with the Chi-square test.Results: Tumour delineation was significantly better in PB and PA compared with PS (P = 0.02). The evaluation of image quality was similar for the three protocols (all, P > 0.05). The highest CNR was observed with PB and was significantly better compared to PA (P = 0.02) and PS (P = 0.0002).Conclusion: In patients with PDAC, a low-tube-voltage, high-iodine-load protocol improves tumour delineation and CNR leading to higher tumour conspicuity compared to standard protocol MDCT.Key Points: • Low-tube-voltage high-iodine-load MDCT improves pancreatic cancer conspicuity compared to a standard protocol. • The pancreas-to-tumour attenuation difference increases significantly by reducing the tube voltage. • The radiation exposure dose decreases by reducing the tube voltage. [ABSTRACT FROM AUTHOR]

Purpose: To assess liver perfusion-CT (P-CT) parameters derived from peak-splenic (PSE) versus peak-renal enhancement (PRE) maximum slope-based modelling in different levels of portal-venous hypertension (PVH).Material and Methods: Twenty-four patients (16 men; mean age 68 ± 10 years) who underwent dynamic P-CT for detection of hepatocellular carcinoma (HCC) were retrospectively divided into three groups: (1) without PVH (n = 8), (2) with PVH (n = 8), (3) with PVH and thrombosis (n = 8). Time to PSE and PRE and arterial liver perfusion (ALP), portal-venous liver perfusion (PLP) and hepatic perfusion-index (HPI) of the liver and HCC derived from PSE- versus PRE-based modelling were compared between the groups.Results: Time to PSE was significantly longer in PVH groups 2 and 3 (P = 0.02), whereas PRE was similar in groups 1, 2 and 3 (P > 0.05). In group 1, liver and HCC perfusion parameters were similar for PSE- and PRE-based modelling (all P > 0.05), whereas significant differences were seen for PLP and HPI (liver only) in group 2 and ALP in group 3 (all P < 0.05).Conclusion: PSE is delayed in patients with PVH, resulting in a miscalculation of PSE-based P-CT parameters. Maximum slope-based P-CT might be improved by replacing PSE with PRE-modelling, whereas the difference between PSE and PRE might serve as a non-invasive biomarker of PVH.Key Points: • Peak-splenic enhancement is decreased and delayed in patients with portal-venous hypertension • The maximum-slope method uses PSE to calculate arterial and portal-venous liver perfusion • Peak-renal enhancement (PRE) is insensitive to PVH and might improve perfusion modelling • The difference between PSE and PRE might serve as a non-invasive PVH biomarker. [ABSTRACT FROM AUTHOR]

Objectives: To retrospectively evaluate short linear shadows connecting pulmonary segmental arteries to oblique fissures in thin-section CT images and determine their anatomical basis.Methods: CT scanning was performed on 108 patients and 11 lung specimens with no lung diseases around the oblique fissures or hila. Two radiologists evaluated the imaging. The parameters included length, thickness of short linear shadows, pulmonary segmental artery variations, and traction interlobar fissures, etc.Results: The short linear shadows were not related to sex, age, or smoking history. The lengths of the short linear shadows were generally within 10 mm. The thicknesses of the short linear shadows ranged from 1 to 2 mm. Of the patients, 26.9 % showed pulmonary segmental artery variations; 66.7 % of short linear shadows pulled oblique fissures. In three-dimensional images, the short linear shadows appeared as arc planes, with one side edge connected to the oblique fissure, one side edge connected to a pulmonary segmental artery. On the tissue slices, the short linear shadow exhibited a band structure composed of connective tissues, small blood vessels, and small lymphatic vessels.Conclusions: Short linear shadows are a type of normal intrapulmonary membranes and can maintain the integrity of the oblique fissures and hilar structure.Key Points: • Volumetric thin-section CT scanning is commonly used to study lung anatomy. • Short linear shadows are a common intrapulmonary structure in thin-section CT. • Short linear shadows correlate with band structures on the correlative tissue slices. [ABSTRACT FROM AUTHOR]

Objective: To retrospectively compare image quality of a lowered dose CT protocol to a standard CT protocol in children with suspicion of craniosynostosis.Methods: Forty-eight patients (age 0- 35 months), who presented with a cranial deformity underwent cranial 3D CT to assess sutural patency: between 2009 - 2010, 24 patients were imaged with a standard protocol (CTDIvol 32.18 mGy), from 2011-2012, 24 underwent a low dose protocol (0.94 mGy) combined with iterative reconstruction. Image quality was evaluated by both expert reading and objective analysis. Differences were assessed by independent t-test and Mann-Whitney U test, interreader agreement by Cohen's Kappa test.Results: Effective dose of the low dose protocol was 0.08 mSv, corresponding to a reduction of 97 %. Image quality was similar in both groups in terms of overall diagnostic acceptability, objective noise measurements, subjective cranial bone edge sharpness and presence of artefacts. For objective sharpness of cranial bone-brain interface and subjective perception of noise, the images of the low dose protocol were superior. For all evaluated structures, interreader agreement was moderate to almost perfect.Conclusion: In the diagnosis of craniosynostosis in children with cranial deformities, a dedicated sub 0.1 mSv cranial 3DCT protocol can be used without loss in image quality.Key Points: 3DCT is used for the diagnosis of craniosynostosis. Imaging protocols should be optimized to minimize radiation exposure to children. Combining 80 kVp with iterative reconstruction can help to reduce dose. A sub 0.1 mSv cranial 3DCT protocol can be used without loss of diagnostic quality. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate visualization of the right adrenal vein (RAV) with multidetector CT and non-contrast-enhanced MR imaging in patients with primary aldosteronism.Methods: A total of 125 patients (67 men) scheduled for adrenal venous sampling (AVS) were included. Dynamic 64-detector-row CT and balanced steady-state free precession-based non-contrast-enhanced 3-T MR imaging were performed. RAV visualization based on a four-point score was documented. Both anatomical location and variation on cross-sectional imaging were evaluated, and the findings were compared with catheter venography as the gold standard.Results: The RAV was visualized in 93.2% by CT and 84.8% by MR imaging (p = 0.02). Positive predictive values of RAV visualization were 100% for CT and 95.2% for MR imaging. Imaging score was significantly higher in CT than MR imaging (p < 0.01). The RAV formed a common trunk with an accessory hepatic vein in 16% of patients. The RAV orifice level on cross-sectional imaging was concordant with catheter venography within the range of 1/3 vertebral height in >70% of subjects. Success rate of AVS was 99.2%.Conclusions: Dynamic CT is a reliable way to map the RAV prior to AVS. Non-contrast-enhanced MR imaging is an alternative when there is a risk of complication from contrast media or radiation exposure.Key Points: Dynamic CT and non-contrast-enhanced MR imaging detect the right adrenal vein (RAV). Dynamic CT can visualize the RAV more than non-contrast-enhanced MR imaging. Mapping the RAV helps to achieve successful adrenal venous sampling. Sixteen per cent of RAVs share the common trunk with accessory hepatic veins. [ABSTRACT FROM AUTHOR]

Objectives: To introduce efficient stereological approaches for estimating the volume of a normal or enlarged spleen from MDCT. Methods: All study participants underwent an abdominal MDCT. The first group included 20 consecutive patients with splenomegaly and the second group consisted of 20 subjects with a normal spleen. Splenic volume estimations were performed using the stereological point counting method. Stereological assessments were optimized using the systematic slice sampling procedure. Planimetric measurements based on manual tracing of splenic boundaries on each slice were taken as reference values. Results: Stereological analysis using five to eight systematically sampled slices provided enlarged splenic volume estimations with a mean precision of 4.9 ± 1.0 % in a mean time of 2.3 ± 0.4 min. A similar measurement duration and error was observed for normal splenic volume assessment using four to seven systematically selected slices. These stereological approaches slightly but insignificantly overestimated the volume of a normal and enlarged spleen compared to planimetry ( P > 0.05) with a mean difference of −1.3 ± 4.3 % and −2.7 ± 5.2 %, respectively. The two methods were highly correlated (r ≥ 0.96). The variability of repeated stereological estimations was below 3.8 %. Conclusions: The proposed stereological approaches enable the rapid, reproducible, and accurate splenic volume estimation from MDCT data in patients with or without splenomegaly. Key Points: • New efficient stereological approaches are proposed for spleen volumetry from MDCT • These volumetric approaches are applicable in patients with or without splenomegaly • Stereological splenic volume estimations from MDCT are rapid, reproducible, and accurate [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to determine the optimal cut-off value of lymph node size for diagnosing metastasis in gastric cancer with multidetector-row computed tomography (MDCT) after categorizing perigastric lymph nodes into three regions. Methods: The study included 90 gastric cancer patients who underwent gastrectomy. The long-axis diameter (LAD) and short-axis diameter (SAD) of all visualized lymph nodes were measured with transverse MDCT images. The locations of lymph nodes were categorized into three regions: lesser curvature, greater curvature, and suprapancreatic. The diagnostic value of lymph node metastasis was assessed with receiver operating characteristic (ROC) analysis. Results: The area under the curve was larger for SAD than LAD in all groups. The optimal cut-off values of SAD were determined as follows: overall, 9 mm; differentiated type, 9 mm; undifferentiated type, 8 mm; lesser curvature region, 7 mm; greater curvature region, 6 mm; and suprapancreatic region, 9 mm. The diagnostic accuracies for lymph node metastasis using individual cut-off values were 71.1 % based on histological type and 76.6 % based on region of lymph node location. Conclusions: The diagnostic accuracy of lymph node metastasis in gastric cancer was improved by using individual cut-off values for each lymph node region. Key points: • Multidetector-row computed tomography is widely used to predict pathological nodal status. • An optimal cut-off value of lymph node size has not been determined. • Cut-off values were assessed according to histology and nodal location. • The optimal cut-off values differed based on histology and nodal location. • Diagnostic accuracy was improved by using individual cut-off values for each region. [ABSTRACT FROM AUTHOR]

Objective: Iterative reconstruction (IR) allows diagnostic CT imaging with less radiation exposure than filtered back projection (FBP). We studied an IR low-dose CT abdomen/pelvis (LDCTAP) protocol, designed to image at an effective dose (ED) approximating 1 mSv in patients with Crohn's disease (CD). Methods: Forty patients, mean age 37 ± 13.4 years (range 17-69), with CD underwent two synchronous CT protocols (conventional-dose (CDCTAP) and LDCTAP). CDCTAP and LDCTAP images were compared for diagnostic acceptability, yield, image quality and ED (in millisieverts). The optimal level of IR for LDCTAP was also studied. Results: LDCTAP yielded a mean ED of 1.3 ± 0.8 mSv compared with 4.7 ± 2.9 mSv for CDCTAP, reducing ED by 73.7 ± 3.3 % (mean dose reduction, 3.5 ± 2.1 mSv; P < 0.001) and dose length product by 73.6 ± 2.6 % ( P < 0.001). Sub-millisievert (0.84 mSv) imaging was performed for patients with a body mass index (BMI) less than 25 (i.e. 63 % of our cohort). LDCTAP resulted in increased image noise and reduced diagnostic acceptability compared with CDCTAP despite use of IR, but detection of extra-luminal complications was comparable. Conclusion: Patients with suspected active CD can be adequately imaged using LDCTAP, yielding comparable information regarding extent, activity and complications of CD compared with CDCTAP, but with 74 % less dose. LDCTAP at doses equivalent to that of two abdominal radiographs represents a feasible alternative to CDCTAP. Key points: • Radiation dose is a concern when imaging patients with Crohn's disease. • New techniques allow low-dose abdominopelvic CT with acceptable image quality. • Using hybrid iterative reconstruction, its diagnostic yield compares well with that of conventional CT. • Sub-millisievert CT of patients with Crohn's disease appears technically and clinically feasible. [ABSTRACT FROM AUTHOR]

Objective: To perform a meta-analysis to determine sensitivity and specificity estimates of helical CT-enteroclysis in the detection of small-bowel tumours. Methods: A search for relevant articles published from January 1992 to November 2010 was performed. Study design, patient characteristics and 2 × 2 contingency tables were recorded for eligible studies. Heterogeneity was assessed with the I statistic. A bivariate generalised linear random-effects model was used to summarise sensitivity and specificity estimates for small-bowel tumour detection on a per-patient basis. Sensitivity and specificity estimates were compared in different subgroups. Results: Twelve studies (696 patients) were eligible. The mean small-bowel tumour prevalence was 22.6 % (range 7.7-45.8 %). Inter-study heterogeneity was substantial for sensitivity ( I = 66.9 %; 95 % CI 28.7-88.5 %) and low for specificity ( I = 10.6 %; 95 % CI 0.0-55.0 %). On a per-patient basis, pooled sensitivity was 92.8 % (95 % CI 71.3-98.5 %) and pooled specificity 99.2 % (95 % CI 94.2-99.9 %) for the diagnosis of small-bowel tumour. Subgroup analysis revealed that small-bowel preparation, more than one imaging pass and large volumes (≥2 L) of enteral contrast agent did not improve tumour detection. Conclusion: Our meta-analysis confirms that helical CT-enteroclysis has high degrees of sensitivity and specificity for small-bowel tumour detection. However, our findings reinforce the need for more standardised individual studies. Key Points: • Helical CT-enteroclysis is highly sensitive for the diagnosis of small-bowel tumours. • Helical CT-enteroclysis is highly specific for the diagnosis of small-bowel tumours, • Helical CT-enteroclysis can be used as a first-line investigation. • A single enteric phase examination provides optimal tumour detection. [ABSTRACT FROM AUTHOR]

Objectives: To compare image quality and radiation dose of high-pitch dual-source computed tomography (DSCT), dual energy CT (DECT) and conventional single-source spiral CT (SCT) for pulmonary CT angiography (CTA) on a 128-slice CT system. Methods: Pulmonary CTA was performed with five protocols: high-pitch DSCT (100 kV), high-pitch DSCT (120 kV), DECT (100/140 kV), SCT (100 kV), and SCT (120 kV). For each protocol, 30 sex, age, and body-mass-index (mean 25.3 kg/m) matched patients were identified. Retrospectively, two observers subjectively assessed image quality, measured CT attenuation (HU±SD) at seven central and peripheral levels, and calculated signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR). Radiation exposure parameters (CTDIvol and DLP) were compared. Results: Subjective image quality was rated good to excellent in >92% (>138/150) with an interobserver agreement of 91.4%. The five protocols did not significantly differ in image quality, neither by subjective, nor by objective measures (SNR, CNR). By contrast, radiation exposure differed between protocols: significant lower radiation was achieved by using high-pitch DSCT at 100 kV ( p < 0.01 in all). Radiation exposure of DECT was in between SCT at 100 kV and 120 kV. Conclusions: SCT, high-pitch DSCT, and DECT protocols techniques result in similar subjective and objective image quality, but radiation exposure was significantly lower with high-pitch DSCT at 100 kV. Key Points: [ABSTRACT FROM AUTHOR]

A multicenter study has been employed to evaluate the diagnostic efficacy of magnetic resonance imaging (MRI) using the new liver-specific contrast agent gadoxetic acid (Gd-EOB-DTPA, Primovist), as opposed to contrast-enhanced biphasic spiral computed tomography (CT), in the diagnosis of focal liver lesions, compared with a standard of reference (SOR). One hundred and sixty-nine patients with hepatic lesions eligible for surgery underwent Gd-EOB-DTPA-enhanced MRI as well as CT within 6 weeks. Pathologic evaluation of the liver specimen combined with intraoperative ultrasound established the SOR. Data sets were evaluated on-site (14 investigators) and off-site (three independent blinded readers). Gd-EOB-DTPA was well tolerated. Three hundred and two lesions were detected in 131 patients valid for analysis by SOR. The frequency of correctly detected lesions was significantly higher on Gd-EOB-DTPA-enhanced MRI compared with CT in the clinical evaluation [10.44%; 95% confidence interval (CI): 4.88, 16.0]. In the blinded reading there was a trend towards Gd-EOB-DTPA-enhanced MRI, not reaching statistical significance (2.14%; 95% CI: −4.32, 8.6). However, the highest rate of correctly detected lesions with a diameter below 1 cm was achieved by Gd-EOB-DTPA-enhanced MRI. Differential diagnosis was superior for Gd-EOB-DTPA-enhanced MRI (82.1%) versus CT (71.0%). A change in surgical therapy was documented in 19 of 131 patients (14.5%) post Gd-EOB-DTPA-enhanced MRI. Gd-EOB-DTPA-enhanced MRI was superior in the diagnosis and therapeutic management of focal liver lesions compared with CT. [ABSTRACT FROM AUTHOR]

This study was designed to define the current role of multislice spiral computed tomography (MSCT) for the diagnosis of coronary in-stent restenosis using a meta-analytic process. Restenosis remains a limitation after coronary stent implantation and contributes to a substantial number of coronary re-assessments by conventional invasive coronary angiography (CA). We identified 15 studies (807 patients) evaluating in-stent restenosis by means of both MSCT (≥16 slices) and conventional CA until February 2007. After data extraction the analysis was performed according to a random-effects model. The analysis pooled the results from 15 studies with a total of 1,175 stents. A substantial number of unassessable stents (13%) were excluded from the analysis underscoring the shortcomings of MSCT. With this major limitation the diagnostic performance of MSCT for in-stent restenosis detection can be summarized as follows: the sensitivity and specificity were 84% [95% confidence interval (CI) 77–89%] and 91% (95% CI 89–93%), respectively, with positive and negative likelihood ratios of 12.2 (95% CI 6.6–22.6) and 0.23 (95% CI 0.17–0.31), respectively, and with a diagnostic odds ratio of 67.9 (95% CI 34.4–134.1). MSCT has shortcomings difficult to overcome in daily practice for in-stent restenosis detection and continues to have moderately high sensitivity and specificity. The diagnostic role of this emerging technology as an alternative to CA for in-stent restenosis detection remains limited. [ABSTRACT FROM AUTHOR]

Cardiac dysfunction may be suggested at computed tomography (CT) exams by the presence of morphological abnormalities such as cardiac enlargement and thickening of the pulmonary interlobular septa. However, these morphological signs are non specific. We evaluated whether right-to-left cardiac transit time of contrast during single-level timing scans could predict the cardiac output and ejection fraction. In a consecutive group of 100 patients referred for body CT, a preliminary single-level study was used to measure the right-to-left ventricular transit time of intravenously injected contrast medium. In all these patients, the cardiac index (cardiac output corrected for body surface area, CI) and ejection fraction (EF) were calculated using cardiac magnetic resonance imaging (CMR). Data of the first half (50 patients, group A) were used to establish a method and concept to predict the cardiac index and ejection fraction with CT. The method was validated in the next half (50 patients, group B) by comparing the predicted CT results with those obtained with CMR. There was a good correlation of the observed CI with CMR and observed transit time on CT in group B (P < 0.05; R(2) 0.70 ). Functional CT estimates of CI and EF in group B correlated well with the CMR results for CI and EF (P < 0.05; R(2) 0.66 for CI and P < 0.05; R(2) 0.49 for EF). The presence of a right-to-left ventricular transit time of more than 10.5 s indicated cardiac dysfunction with a specificity and positive predictive value of 100%. Right-to-left transit time obtained during routine body CT exams can provide valuable physiological information on global cardiac function. [ABSTRACT FROM AUTHOR]

Computed tomography (CT) is still the primary imaging modality following acute stroke. To evaluate a prototype of software for the calculation of color-coded whole-brain perfused blood volume (PBV) images from CT angiography (CTA) and nonenhanced CT (NECT) scans, we studied 14 patients with suspected acute ischemia of the anterior cerebral circulation. PBV calculations were performed retrospectively. The detection rate of ischemic changes in the PBV images was compared with NECT. The volume of ischemic changes in PBV was correlated with the infarct volume on follow-up examination taking potential vessel recanalization into account. PBV demonstrated ischemic changes in 12/12 patients with proven infarction and was superior to NECT (8/12) in the detection of early ischemia. Moreover, PBV demonstrated the best correlation coefficient with the follow-up infarct volume (Pearson's R = 0.957; P = 0.003) for patients with proven recanalization of initially occluded cerebral arteries. In summary, PBV appears to be more accurate in the detection of early infarction compared to NECT and mainly visualizes the irreversibly damaged ischemic tissue. [ABSTRACT FROM AUTHOR]

The aim of our study was to evaluate the use of a 1-molar gadolinium chelate (gadobutrol) as an alternative contrast medium for computed tomography angiography (CTA) exams of the aorta. CTA exams of the thoracic and/or abdominal aorta were performed on 15 patients with contraindications for the use of iodine who were not suitable for magnetic resonance examinations. The exams were performed with a 16-detector row scanner, injecting a mean dose of 0.37 mmol Gd/kg of body weight at a flow rate of 4 ml/s. Creatinine levels were obtained prior to the exam in patients with impaired renal function, and 24 and 48 h afterwards. The mean attenuation values obtained in the middle ascending and middle descending thoracic aorta were 202.3 and 216.8, respectively. The mean HU values of the abdominal aorta were 210.4 at the level of the renal arteries and 186.8 in the aortic bifurcation. All the exams were considered diagnostically adequate. No significant increase in serum creatinine was observed 24 and 48 h after the exam. We believe that gadobutrol could be an alternative contrast medium for CTA exams with 16-detector row scanners in patients with contraindications for iodinated contrast medium. [ABSTRACT FROM AUTHOR]

The purpose of this study was to describe the thin-section computed tomographic (CT) features of focal interstitial fibrosis manifesting as nodular ground-glass opacity (GGO) and its changes during follow-up. The thin-section CT findings of pathologically proven focal interstitial fibrosis manifesting as nodular GGO were retrospectively evaluated in nine patients (five women and four men; mean age, 59.3 years; age range, 34-81 years). The thin-section CT findings of each lesion were analyzed for multiplicity, location, shape, margin characteristics, pleural retraction or vascular convergence, size and internal attenuation, lesion internal features and lesion changes on follow-up CT scans (mean 90 days, range 5 to 215 days). All lesions manifested as a solitary nodular GGO (100%), and seven of the nine lesions (77.8%) were located in the upper lobe. Focal interstitial fibrosis was round or oval in shape in five cases (55.6%), complex in shape in three cases (33.3%) and polygonal in one case (11.1%). Lesion margins were smooth in five patients (55.6%), irregular in three (33.3%) and spiculated in one (11.1%). Pleural retraction or vascular convergence was present in two patients (22.2%). Lesions measured 4.8 mm to 25.5 mm (mean, 11.5 mm) and had attenuations ranging from -151 to -699 HU (mean, -514.7 HU). Eight (88.9%) manifested as pure nodular GGOs and one as mixed GGO with a spiculated margin. In all patients, no lesion changes were observed in follow-up CT scans. Focal interstitial fibrosis manifesting as nodular GGO usually presents as a solitary nodule with pure GGO on thin-section CT, which does not change significantly during follow-up. [ABSTRACT FROM AUTHOR]

The purpose of this study was to intraindividually evaluate myocardial late enhancement on multislice spiral computed tomography (MSCT) for the assessment of the different stages of myocardial infarction (MI) in comparison with magnetic resonance (MR) imaging. Reperfused MI was successfully induced in seven pigs. Delayed enhancement MR imaging and late-phase MSCT were performed on day 0 as well as 7, 28 and 90 days after the procedure. The pigs were sacrificed, and 2,3,5-triphenyltetrazolin-chloride (TTC) staining was acquired. MI size was compared between the different imaging techniques and over time applying Bland-Altman plots and multivariate analysis with repeated measures. On day 0 the mean MI size was 23.7 +/- 11.8% of the left ventricular area on MSCT and 24.5 +/- 10.6% on MR imaging. On day 90 infarct sizes decreased significantly to 16.9 +/- 8.4% and 18.9 +/- 8.0%, respectively (P = 0.0019). On TTC staining the size of MI was 16.8 +/- 8.2%. Bland-Altman plots showed a good agreement between MSCT and MR imaging with mean deviations ranging from -3.4% to -1.9%. No significant difference between MSCT and MR imaging was found. Myocardial late enhancement on MSCT correlates well with delayed enhancement MR imaging during the different stages of MI and allows for reliable assessment of reperfused MI during acute, subacute and chronic stages. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the accuracy of an automated volumetry software for phantom pulmonary nodules across various 16-slice multislice spiral CT (MSCT) scanners from different vendors. A lung phantom containing five different nodule categories (intraparenchymal, around a vessel, vessel attached, pleural, and attached to the pleura), with each category comprised of 7-9 nodules (total, n = 40) of varying sizes (diameter 3-10 mm; volume 6.62 mm(3)-525 mm(3)), was scanned with four different 16-slice MSCT scanners (Siemens, GE, Philips, Toshiba). Routine and low-dose chest protocols with thin and thick collimations were applied. The data from all scanners were used for further analysis using a dedicated prototype volumetry software. Absolute percentage volume errors (APE) were calculated and compared. The mean APE for all nodules was 8.4% (+/-7.7%) for data acquired with the 16-slice Siemens scanner, 14.3% (+/-11.1%) for the GE scanner, 9.7% (+/-9.6%) for the Philips scanner and 7.5% (+/-7.2%) for the Toshiba scanner, respectively. The lowest APEs were found within the diameter size range of 5-10 mm and volumes >66 mm(3). Nodule volumetry is accurate with a reasonable volume error in data from different scanner vendors. This may have an important impact for intraindividual follow-up studies. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine non-invasively the frequency of ectopic bronchial arteries (BA) (i.e., bronchial arteries originating at a level of the descending aorta other than T5-T6 or from any aortic collateral vessel) on multidetector-row CT angiograms (CTA) obtained in patients with hemoptysis. Over a 5-year period (2000–2005), 251 consecutive patients with hemoptysis underwent multidetector-row CT angiography of the thorax. From this population, 37 patients were excluded because of a suboptimal CTA examination (n = 19), the presence of extensive mediastinal disease (n = 15) or severe chest deformation (n = 3) precluding any precise analysis of the bronchial arteries at CTA. Our final study group included 214 patients who underwent a thin-collimated CT angiogram (contrast agent: 300 to 350 mg/ml) on a 4- (n = 56), 16- (n = 119) and 64- (n = 39) detector-row scanner. The site of origin and distribution of bronchial arteries were analyzed on transverse CT scans, maximum intensity projections and volume-rendered images. The site of the ostium of a bronchial artery was coded as orthotopic when the artery originated from the descending aorta between the levels of the fifth and sixth thoracic vertebrae; all other bronchial arteries were considered ectopic. From the studied population, 137 (64%) patients had only orthotopic bronchial arteries, whereas 77 patients (36%) had at least one bronchial artery of ectopic origin. A total of 147 ectopic arteries were depicted, originating as common bronchial trunks (n = 23; 19%) or isolated right or left bronchial arteries (n = 101; 81%). The most frequent sites of origin of the 124 ostiums were the concavity of the aortic arch (92/124; 74%), the subclavian artery (13/124; 10.5%) and the descending aorta (10/124; 8.5%). The isolated ectopic bronchial arteries supplied the ipsilateral lung in all but three cases. Bronchial artery embolization was indicated in 26 patients. On the basis of CTA information, (1) bronchial embolization was attempted in 24 patients; it was technically successful in 21 patients (orthotopic BAs: 6 patients; orthotopic and ectopic BAs: 3 patients; ectopic BAs: 12 patients) and failed in 3 patients due to an instable catheterization of the ectopic BAs; the absence of additional bronchial arterial supply and no abnormalities of nonbronchial systemic arteries at CTA avoided additional arteriograms in these 3 patients; (2) owing to the iatrogenic risk of the embolization procedure of ectopic BAs, the surgical ligation of the abnormal vessels was the favored therapeutic option in 2 patients. This study enabled the depiction of ectopic bronchial arteries in 36% of the studied population, important anatomical information prior to therapeutic decision making. [ABSTRACT FROM AUTHOR]

Vessel image analysis is crucial when considering therapeutical options for (cardio-) vascular diseases. Our method, VAMPIRE (Vascular Analysis using Multiscale Paths Inferred from Ridges and Edges), involves two parts: a user defines a start- and endpoint upon which a lumen path is automatically defined, and which is used for initialization; the automatic segmentation of the vessel lumen on computed tomographic angiography (CTA) images. Both parts are based on the detection of vessel-like structures by analyzing intensity, edge, and ridge information. A multi-observer evaluation study was performed to compare VAMPIRE with a conventional method on the CTA data of 15 patients with carotid artery stenosis. In addition to the start- and endpoint, the two radiologists required on average 2.5 (SD: 1.9) additional points to define a lumen path when using the conventional method, and 0.1 (SD: 0.3) when using VAMPIRE. The segmentation results were quantitatively evaluated using Similarity Indices, which were slightly lower between VAMPIRE and the two radiologists (respectively 0.90 and 0.88) compared with the Similarity Index between the radiologists (0.92). The evaluation shows that the improved definition of a lumen path requires minimal user interaction, and that using this path as initialization leads to good automatic lumen segmentation results. [ABSTRACT FROM AUTHOR]