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1.
Objectives
To evaluate the diagnostic value of intravoxel incoherent motion (IVIM) and diffusional kurtosis imaging (DKI) parameters in nasal or sinonasal squamous cell carcinoma (SCC) patients to determine local control/failure.Methods
Twenty-eight patients were evaluated. MR acquisition used single-shot spin-echo EPI with 12 b-values. Quantitative parameters (mean value, 25th, 50th and 75th percentiles) of IVIM (perfusion fraction f, pseudo-diffusion coefficient D*, and true-diffusion coefficient D), DKI (kurtosis value K, kurtosis corrected diffusion coefficient Dk) and apparent diffusion coefficient (ADC) were calculated. Parameter values at both the pretreatment and early-treatment period, and the percentage change between these two periods were obtained.Results
Multivariate logistic regression analysis: the percentage changes of D (mean, 25th, 50th, 75th), K (mean, 50th, 75th), Dk (mean, 25th, 50th), and ADC (mean, 25th, 50th) were predictors of local control. ROC curve analysis: the parameter with the highest accuracy = the percentage change of D value with the histogram 25th percentile (0.93 diagnostic accuracy). Multivariate Cox regression analyses: the percentage changes of D (mean, 25th, 50th), K (mean, 50th, 75th), Dk (mean, 25th, 50th) and ADC (mean, 25th, 50th) are predictors.Conclusions
IVIM and DKI parameters, especially the D-value’s histogram 25th percentile, are useful for predicting local control.Key Points
? Noninvasive assessment of treatment outcome in SCC patients was achieved using IVIM/DKI.? Several IVIM and DKI parameters can predict the local control.? Especially, the D-value’s histogram 25th percentile has high diagnostic accuracy.2.
Objective
To evaluate diffusion kurtosis imaging (DKI) and magnetisation transfer imaging (MTI) compared to standard MRI for prostate cancer assessment in a re-biopsy population.Methods
Thirty-patients were imaged at 3 T including DKI (Kapp and Dapp) with b-values 150/450/800/1150/1500 s/mm2 and MTI performed with and without MT saturation. Patients underwent transperineal biopsy based on prospectively defined MRI targets. Receiver-operating characteristic (ROC) analyses assessed the parameters and Wilcoxon-signed ranked test assessed relationships between metrics.Results
Twenty patients had ≥ 1 core positive for cancer in a total of 26 MRI targets (Gleason 3+3 in 8, 3+4 in 12, ≥ 4+3 in 6): 13 peripheral (PZ) and 13 transition zone (TZ). The apparent diffusion coefficient (ADC) and Dapp were significantly lower and the Kapp and MT ratio (MTR) significantly higher in tumour versus benign tissue (all p ≤ 0.005); ROC values 0.767-1.000. Normal TZ had: lower ADC and Dapp and higher Kapp and MTR compared to normal PZ. MTR showed a moderate correlation to Kapp (r = 0.570) and Dapp (r = -0.537) in normal tissue but a poor correlation in tumours. No parameter separated low-grade (Gleason 3+3) from high-grade (≥ 3+4) disease for either PZ (p = 0.414-0.825) or TZ (p = 0.148-0.825).Conclusion
ADC, Dapp, Kapp and MTR all distinguished benign tissue from tumour, but none reliably differentiated low- from high-grade disease.Key Points
? MTR was significantly higher in PZ and TZ tumours versus normal tissue ? K app was significantly lower and D app higher for PZ and TZ tumours ? There was no incremental value for DKI/MTI over mono-exponential ADC parameters ? No parameter could consistently differentiate low-grade (Gleason 3+3) from high-grade (≥ 3+4) disease ? Divergent MTR/DKI values in TZ tumours suggests they offer different functional information3.
Objective
In patients with aortic regurgitation (AR), the effect of static exercise (SE) on global ventricular function and AR severity has not been previously studied.Methods
Resting and SE cardiovascular magnetic resonance (CMR) were prospectively performed in 23 asymptomatic patients with AR.Results
During SE, we observed a decrease in regurgitant volume in both end-diastolic (EDV) and end-systolic (ESV) volume in both ventricles, as well as a slight decrease in LV ejection fraction (EF). Interestingly, responses varied depending on the degree of LV remodelling. Among patients with a greater degree of LV remodelling, we observed a decrease in LVEF (56?±?4 % at rest vs 48?±?7 % during SE, p?=?0.001) as a result of a lower decrease in LVESV (with respect to LVEDV. Among patients with a lower degree of LV remodelling, LVEF remained unchanged. RVEF remained unchanged in both groups.Conclusions
In patients with AR, SE provoked a reduction in preload, LV stroke volume, and regurgitant volume. In those patients with higher LV remodelling, we observed a decrease in LVEF, suggesting a lower LV contractile reserve.Key points
? In patients with aortic regurgitation, static exercise reduced preload volume.? In patients with aortic regurgitation, static exercise reduced stroke volume.? In patients with aortic regurgitation, static exercise reduced regurgitant volume.? In patients with greater remodelling, static exercise unmasked a lower contractile reserve.? Effect of static exercise on aortic regurgitation was assessed by cardiac MR.4.
Aart?J.?van der?Molen Peter?Reimer Ilona?A.?Dekkers Georg?Bongartz Marie-France?Bellin Michele?Bertolotto Olivier?Clement Gertraud?Heinz-Peer Fulvio?Stacul Judith?A.?W.?Webb Henrik?S.?Thomsen
Purpose
The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) has updated its 2011 guidelines on the prevention of post-contrast acute kidney injury (PC-AKI). The results of the literature review and the recommendations based on it, which were used to prepare the new guidelines, are presented in two papers.Areas covered in part 1
Topics reviewed include the terminology used, the best way to measure eGFR, the definition of PC-AKI, and the risk factors for PC-AKI, including whether the risk with intravenous and intra-arterial contrast medium differs.Key Points
? PC-AKI is the preferred term for renal function deterioration after contrast medium.? PC-AKI has many possible causes.? The risk of AKI caused by intravascular contrast medium has been overstated.? Important patient risk factors for PC-AKI are CKD and dehydration.5.
Objectives
To evaluate tissue perfusion and venous susceptibility in ischaemic stroke patients as a means to predict clinical status and early prognosis.Methods
A retrospective study of 51 ischaemic stroke patients were enrolled in this study. Susceptibility, perfusion and National Institute of Health stroke scale (NIHSS) were compared between patients with and without asymmetrically prominent cortical veins (APCVs). The correlation between susceptibility, perfusion and NIHSS was performed.Results
Compared to patients without APCVs, the age of patients with APCVs was statistically older (p?=?0.017). Patients with APCVs at discharge showed clinical deterioration in their NIHSS. Mean transit time (MTT), time to peak (TTP) and cerebral blood flow (CBF) in the stroke hemisphere were statistically delayed/decreased in patients with and without APCVs (all p?<?0.05). In patients with APCVs, the changes in susceptibility positively correlated with increases in MTT and TTP (p?<?0.05). Susceptibility and TTP positively correlated and CBF negatively correlated with NIHSS both at admission and discharge (p?<?0.05).Conclusions
Patients with APCVs have a tendency of deterioration. The presence of APCVs indicates the tissue has increased oxygen extraction fraction. Increased susceptibility from APCVs positively correlated with the delayed MTT and TTP, which reflects the clinical status at admission and predicts an early prognosis.Key points
? Patients with and without APCVs have similar misery perfusion.? Patients with APCVs have a tendency of deterioration compared to those without.? The presence of APCVs indicated the tissue has increased oxygen extraction fraction.? Increased susceptibility from APCVs positively correlated with the MTT and TTP.? Increased susceptibility from APCVs reflected the clinical status at admission.6.
Objectives
Diminished function of the posterior cingulate cortex (PCC) is a typical finding in early Alzheimer’s disease (AD). It is hypothesized that in early stage AD, PCC functioning relates to or reflects hippocampal dysfunction or atrophy. The aim of this study was to examine the relationship between hippocampus function, volume and structural connectivity, and PCC activation during an episodic memory task-related fMRI study in mild cognitive impairment (MCI).Method
MCI patients (n?=?27) underwent episodic memory task-related fMRI, 3D-T1w MRI, 2D T2-FLAIR MRI and diffusion tensor imaging. Stepwise linear regression analysis was performed to examine the relationship between PCC activation and hippocampal activation, hippocampal volume and diffusion measures within the cingulum along the hippocampus.Results
We found a significant relationship between PCC and hippocampus activation during successful episodic memory encoding and correct recognition in MCI patients. We found no relationship between the PCC and structural hippocampal predictors.Conclusions
Our results indicate a relationship between PCC and hippocampus activation during episodic memory engagement in MCI. This may suggest that during episodic memory, functional network deterioration is the most important predictor of PCC functioning in MCI.Key Points
? PCC functioning during episodic memory relates to hippocampal functioning in MCI.? PCC functioning during episodic memory does not relate to hippocampal structure in MCI.? Functional network changes are an important predictor of PCC functioning in MCI.7.
Objectives
This study was aimed at correlating a magnetic resonance index of activity (MaRIA) and a magnetic resonance enterography global score (MEGS) with activity indexes in a paediatric population with Crohn’s disease (CD).Methods
This retrospective study included 32 paediatric patients (median age 14.5 years, 18 male) with proven CD who underwent magnetic resonance enterography (MRE). A correlation analysis was performed on the MRE-based scores, the simplified endoscopic score for CD (SES-CD), the paediatric Crohn’s disease activity index (PCDAI), and C-reactive protein (CRP) levels. Based on PCDAI, comparison of both global MaRIA and MEGS was made between patients with mild and moderate/severe disease activity.Results
Global MaRIA correlated with SES-CD (r?=?0.70, p?=?0.001) and PCDAI (r?=?0.42, p?=?0.016). MEGS correlated with PCDAI (r?=?0.46, p?=?0.007) and CRP levels (r?=?0.35, p?=?0.046). MEGS differed significantly (p?=?0.027) between patients grouped by clinical disease severity.Conclusions
MRE-based global scores correlated with clinical indexes of CD activity. Therefore, they represent a potential useful tool to predict CD activity and severity, as well as a possible promising alternative to endoscopy, to monitor paediatric patients with CD during their follow-up.Key Points
? MRE is widely used to for accurate assessment of CD.? Global MaRIA and MEGS have been suggested as indicators of CD activity.? Paediatric studies comparing MRE-based global scores with clinical CD activity are lacking.? Such scores can serve as predictors of CD activity/severity in paediatric patients.? MRE offers an alternative to clinical score/endoscopy for paediatric CD monitoring.8.
Davide Prezzi Gauraang Bhatnagar Roser Vega Jesica Makanyanga Steve Halligan Stuart Andrew Taylor 《European radiology》2016,26(7):2107-2117
Objectives
To assess the ability of magnetic resonance enterography global score (MEGS) to characterise Crohn’s disease (CD) response to anti-TNF-α therapy.Methods
Thirty-six CD patients (median age 26 years, 20 males) commencing anti-TNF-α therapy with concomitant baseline MRI enterography (MRE) were identified retrospectively. Patients’ clinical course was followed and correlated with subsequent MREs. Scan order was randomised and MEGS (a global activity score) was applied by two blinded radiologists. A physician’s global assessment of the disease activity (remission, mild, moderate or severe) at the time of MRE was assigned. The cohort was divided into clinical responders and non-responders and MEGS compared according to activity status and treatment response. Interobserver agreement was assessed.Results
Median MEGS decreased significantly between baseline and first follow-up in responders (28 versus 6, P?<?0.001) but was unchanged in non-responders (26 versus 18, P?=?0.28). The median MEGS was significantly lower in clinical remission (9) than in moderate (14) or severe (29) activity (P?<?0.001). MEGS correlated significantly with clinical activity (r?=?0.53; P?<?0.001). Interobserver Bland-Altman limits of agreement (BA LoA) were -19.7 to 18.5.Conclusions
MEGS decreases significantly in clinical responders to anti-TNF-α therapy but not in non-responders, demonstrates good interobserver agreement and moderate correlation with clinical disease activity.Key Points
? MRI scores of Crohn’s activity are used increasingly in clinical practice and therapeutic trials.? Such scores have been advocated as biomarkers of therapeutic response.? MEGS reflects clinical response to anti-TNF-α therapy and the clinical classification of disease activity.? MEGS demonstrates good interobserver agreement.9.
Dietmar Tamandl Matthias Paireder Reza Asari Pascal A. Baltzer Sebastian F. Schoppmann Ahmed Ba-Ssalamah 《European radiology》2016,26(5):1359-1367
Objectives
To assess the impact of sarcopenia and alterations in body composition parameters (BCPs) on survival after surgery for oesophageal and gastro-oesophageal junction cancer (OC).Methods
200 consecutive patients who underwent resection for OC between 2006 and 2013 were selected. Preoperative CTs were used to assess markers of sarcopenia and body composition (total muscle area [TMA], fat-free mass index [FFMi], fat mass index [FMi], subcutaneous, visceral and retrorenal fat [RRF], muscle attenuation). Cox regression was used to assess the primary outcome parameter of overall survival (OS) after surgery.Results
130 patients (65 %) had sarcopenia based on preoperative CT examinations. Sarcopenic patients showed impaired survival compared to non-sarcopenic individuals (hazard ratio [HR] 1.87, 95 % confidence interval [CI] 1.15–3.03, p?=?0.011). Furthermore, low skeletal muscle attenuation (HR 1.91, 95 % CI 1.12–3.28, p?=?0.019) and increased FMi (HR 3.47, 95 % CI 1.27–9.50, p?=?0.016) were associated with impaired outcome. In the multivariate analysis, including a composite score (CSS) of those three parameters and clinical variables, only CSS, T-stage and surgical resection margin remained significant predictors of OS.Conclusion
Patients who show signs of sarcopenia and alterations in BCPs on preoperative CT images have impaired long-term outcome after surgery for OC.Key Points
? Sarcopenia is associated with impaired OS after surgery for oesophageal cancer.? Other body composition parameters are also associated with impaired survival.? This influence on survival is independent of established clinical parameters.? Sarcopenia provides a better estimation of cachexia than BMI.? Sarcopenia assessment could be considered in risk/benefit stratification before oesophagectomy.10.
Objective
To analyze the outcomes of a magnesium alloy covered stent (MACS) for a lateral aneurysm model in common carotid artery (CCA).Methods
In 32 rabbits, a MACS (group A, n?=?17) or a Willis covered stent (WCS; group B, n?=?15) was inserted and the rabbits were sacrificed 1, 3, 6, or 12 months after stenting. Angiography and intravascular ultrasound (IVUS) were performed at 3, 6, and 12 months. Scanning electron microscopy was performed for six stents in each group at 1, 3, and 6 months, and histopathology and histomorphology were conducted at 3 (n?=?4), 6 (n?=?4), and 12 (n?=?12) months.Results
Final angiography showed complete occlusion of the aneurysms in 12 cases. IVUS at 6 and 12 months revealed a significant increase in mean lumen area of the stented CCA in group A and also showed greater mean lumen area in group A than in group B. The endothelialization process was quicker in group A than in group B.Conclusion
MACS is effective for occlusion of lateral aneurysms and is superior to WCS in growth of the stented CCA and endothelialization. Further work is needed to make this device available for human use.Key points
? The MACS is an effective approach for occlusion of a lateral aneurysm.? IVUS showed that the CCA could grow following degradation of the MACS.? The lumen area of the stented CCA was excellent in MACS.? HE staining displayed the degradation of the magnesium alloy stent.? Combination of IVUS and DSA were applied in this study.11.
Purpose
To develop a prediction model to distinguish between transition zone (TZ) cancers and benign prostatic hyperplasia (BPH) on multi-parametric prostate magnetic resonance imaging (mp-MRI).Materials and methods
This retrospective study enrolled 60 patients with either BPH or TZ cancer, who had undergone 3 T-MRI. We generated ten parameters for T2-weighted images (T2WI), diffusion-weighted images (DWI) and dynamic MRI. Using a t-test and multivariate logistic regression (LR) analysis to evaluate the parameters’ accuracy, we developed LR models. We calculated the area under the receiver operating characteristic curve (ROC) of LR models by a leave-one-out cross-validation procedure, and the LR model’s performance was compared with radiologists’ performance with their opinion and with the Prostate Imaging Reporting and Data System (Pi-RADS v2) score.Results
Multivariate LR analysis showed that only standardized T2WI signal and mean apparent diffusion coefficient (ADC) maintained their independent values (P < 0.001). The validation analysis showed that the AUC of the final LR model was comparable to that of board-certified radiologists, and superior to that of Pi-RADS scores.Conclusion
A standardized T2WI and mean ADC were independent factors for distinguishing between BPH and TZ cancer. The performance of the LR model was comparable to that of experienced radiologists.Key Points
? It is difficult to diagnose transition zone (TZ) cancer.? We performed quantitative image analysis in multi-parametric MRI.? Standardized-T2WI and mean-ADC were independent factors for diagnosing TZ cancer.? We developed logistic-regression analysis to diagnose TZ cancer accurately.? The performance of the logistic-regression analysis was higher than PIRADSv2.12.
Objective
To investigate the added value of secondary reports issued by radiologists subspecializing in gynaecologic imaging for determining deep myometrial invasion of endometrial cancer on MRI.Methods
Initial (from referring institutions) and secondary (by subspecialized radiologists) interpretations of MRI of 55 patients with endometrial cancer were retrospectively reviewed. A radiologist blinded to clinicopathological information assessed both reports for the presence of deep myometrial invasion. Reference standard was based on hysterectomy specimens. Kappa coefficients (k) were used to measure their concordance. McNemar testing and receiver operating characteristic (ROC) analysis was used to compare sensitivities, specificities and areas under the curves (AUCs).Results
Deep myometrial invasion was present in 25 (45.5 %) patients. Among 27.3 % (15/55; k?=?0.458) patients with discrepant results, secondary interpretations were correct in 10 (66.7 %) cases. Sensitivity was higher in secondary than in initial reports (76.0 % vs. 48.0 %, p?=?0.039) while no significant difference was seen in specificity (70.0 % vs. 76.7 %, p?=?0.668). At ROC analysis, there was a tendency for higher AUCs in secondary reports (0.785 vs 0.669, p?=?0.096).Conclusion
Secondary readings of MRI by subspecialized gynaecologic oncologic radiologists may provide incremental value in determining deep myometrial invasion of endometrial cancer.Key Points
? Deep myometrial invasion is an important prognostic factor in endometrial cancer.? Assessment of deep myometrial invasion is often discrepant between initial and secondary reports.? Secondary reports showed higher sensitivity and accuracy.? Secondary review of MRI may provide incremental value in endometrial cancer patients.13.
Objectives
To evaluate shear wave elastography (SWE) for focal lesions in major salivary glands.Methods
Sixty lesions (49 parotid, 11 submandibular) undergoing routine ultrasound (grey scale and Doppler) also underwent SWE before US-guided needle aspiration for cytology. Quantitative indices of the shear elastic modulus (stiffness) were compared with cytological results.Results
Fifty-five lesions were benign (21 pleomorphic adenomas, 18 Warthin’s tumours; 16 others) and 5 malignant (2 mucoepidermoid carcinomas, 1 myoepithelial carcinoma, 1 B-cell lymphoma, 1 nodal metastasis). Shear modulus of benign lesions, median 18.3 kPa, overlapped appreciably with malignant lesions, median 13.5 kPa. However, 2 mucoepidermoid carcinomas had the highest stiffness values (81.9 kPa, 132.0 kPa). Stiffness of pleomorphic adenomas (median 22.5 kPa) was higher than Warthin’s tumours (16.9 kPa) (P?=?0.05 Mann–Whitney U-test). The standard deviation of stiffness values within a lesion, used as an indicator of spatial heterogeneity, was highest in mucoepidermoid cancers (median 44.2 kPa), followed by pleomorphic adenomas (median 12.4 kPa) and remaining lesions (medians 1.4–10.3 kPa).Conclusion
This study shows a degree of clustering of SWE indices according to pathology although it appears that SWE has suboptimal performance for ruling out malignancy, thus limiting its use in routine practice.Key Points
? Shear wave elastography is a feasible technique for focal salivary gland lesions.? Elastographic artefacts aggravated by the regional anatomy may hinder this technique.? Elastographic indices vary according to pathology but there is appreciable overlap.? Overlapping indices for malignant and benign lesions limit its utility.? Pleomorphic adenomas have higher elasticity indices, i.e. are stiffer, than Warthin’s tumours.14.
Objectives
MR venography (MRV) protocols have used bloodpool contrast agents and long scan sequences to identify patients suitable for treatment and preoperatively. However, variable availability of bloodpool contrast agents, high costs and a need to shorten acquisition times for routine MR protocols hamper everyday practice.Materials
20 patients (11 men; mean age 54?±?11.8 years; body mass index 23.6?±?2.5) were enrolled in this prospective study. An intra-individual comparison of image quality, interpretation and findings for two different contrast agents (regular gadolinium contrast agent gadobutrol vs. bloodpool contrast agent gadofosveset-trisodium) and two different scan protocols (long acquisition time protocol using a high-resolution fast field echo (FFE) sequence vs. short acquisition time protocol using an ultra-fast gradient echo (GE) sequence) were performed.Results
Image quality (average of 4.94 vs. 4.92 on a five-point scale), interpretation and contrast-to-noise ratio (44 vs. 45) were equal for both contrast agents. Image findings showed no statistical significant differences between the MR protocols or contrast agents (overall p?=?0.328).Conclusions
For high-resolution MRV, it is possible to replace gadofosveset-trisodium with gadobutrol. Furthermore, an ultra-fast GE sequence for MRV might considerably shorten acquisition time, without loss of image quality or diagnostic yield.Key Points
? High-quality MRV can be performed with a regular gadolinium-based contrast agent.? Ultra-fast GRE vs. HR-FFE MRV: equally suitable for evaluation of venous obstruction.? Regular gadolinium-based contrast agent can supersede a bloodpool contrast agent for MRV.? Equal confidence for gadobutrol vs gadofosveset-trisodium in MRV.? MRV accessible for routine daily practice.15.
Purpose
To evaluate revised PROPELLER (RevPROP) for T2-weighted imaging (T2WI) of the prostate as a substitute for turbo spin echo (TSE).Materials and methods
Three-Tesla MR images of 50 patients with 55 cancer-suspicious lesions were prospectively evaluated. Findings were correlated with histopathology after MRI-guided biopsy. T2 RevPROP, T2 TSE, diffusion-weighted imaging, dynamic contrast enhancement, and MR-spectroscopy were acquired. RevPROP was compared to TSE concerning PI-RADS scores, lesion size, lesion signal-intensity, lesion contrast, artefacts, and image quality.Results
There were 41 carcinomas in 55 cancer-suspicious lesions. RevPROP detected 41 of 41 carcinomas (100%) and 54 of 55 lesions (98.2%). TSE detected 39 of 41 carcinomas (95.1%) and 51 of 55 lesions (92.7%). RevPROP showed fewer artefacts and higher image quality (each p?<?0.001). No differences were observed between single and overall PI-RADS scores based on RevPROP or TSE (p?=?0.106 and p?=?0.107). Lesion size was not different (p?=?0.105). T2-signal intensity of lesions was higher and T2-contrast of lesions was lower on RevPROP (each p?<?0.001).Conclusion
For prostate cancer detection RevPROP is superior to TSE with respect to motion robustness, image quality and detection rates of lesions. Therefore, RevPROP might be used as a substitute for T2WI.Key points
? Revised PROPELLER can be used as a substitute for T2-weighted prostate imaging.? Revised PROPELLER detected more carcinomas and more suspicious lesions than TSE.? Revised PROPELLER showed fewer artefacts and better image quality compared to TSE.? There were no significant differences in PI-RADS scores between revised PROPELLER and TSE.? The lower T2-contrast of revised PROPELLER did not impair its diagnostic quality.16.
Objective
To optimise image quality and reduce radiation exposure for infant body CT imaging.Methods
An image quality CT phantom was created to model the infant body habitus. Image noise, spatial resolution, low contrast detectability and tube current modulation (TCM) were measured after adjusting CT protocol parameters. Reconstruction method (FBP, hybrid iterative and model-based iterative), image quality reference parameter, helical pitch and beam collimation were systematically investigated for their influence on image quality and radiation output.Results
Both spatial and low contrast resolution were significantly improved with model-based iterative reconstruction (p?<?0.05). A change in the helical pitch from 0.969 to 1.375 resulted in a 23 % reduction in total TCM, while a change in collimation from 20 to 40 mm resulted in a 46 % TCM reduction. Image noise and radiation output were both unaffected by changes in collimation, while an increase in pitch enabled a dose length product reduction of ~6 % at equivalent noise. An optimised protocol with ~30 % dose reduction was identified using model-based iterative reconstruction.Conclusions
CT technology continues to evolve and require protocol redesign. This work provides an example of how an infant-specific phantom is essential for leveraging this technology to maintain image quality while reducing radiation exposure.Key Points
? A size-specific phantom is critical in protocol development for infant CT.? New reconstruction technology enables ~30 % dose reduction at equivalent image quality.? A consistent performance is observed for this scanner system across protocol changes.? A tradeoff exists between reducing exposure time and enabling tube current modulation.17.
Objective
Our aim was to determine the prevalence of tuberculosis (TB), the number needed to screen (NNS), and the diagnostic accuracy of chest X-ray (CXR) screening to detect active pulmonary TB during the 2015 European refugee crisis.Materials and methods
We evaluated data of all refugees who underwent CXR screening in a single-centre of one German metropolitan area in 2015. We determined the prevalence of TB, NNS, and accuracy of CXR to detect active pulmonary TB. Reference method for active TB was the database of all definite TB cases registered at the Department of Public Health.Results
A total of 17,487 immigrants underwent single-centre CXR screening in 2015; prevalence of definite pulmonary TB was 0.103%. The NNS for detecting one case of active pulmonary TB was 1749. CXR had a sensitivity of 55.6% [95% confidence interval (CI) 30.8–78.5%) and a specificity 98.3% (CI 98.1–98.5%) to reveal one case of active TB.Conclusion
Our single-centre study indicates that chest X-ray screening for TB during the 2015 European refugee crisis was of low yield due the low prevalence of TB and high number needed to screen, thus implicating the need for improved screening algorithms adapted to the overwhelming number of refugees.Key Points
? Prevalence of pulmonary tuberculosis (TB) among refugees in 2015 was low (0.103%).? The number needed to screen to detect one case of active pulmonary TB was 1749.? Tuberculosis X-ray screening resulted in a low sensitivity and high specificity.? Tuberculosis X-ray screening during the European refugee crisis is of low yield.? Improved screening algorithms are needed due to the overwhelming the number of refugees.18.
Objectives
To develop a prediction model for the variability range of lung nodule volumetry and validate the model in detecting nodule growth.Materials and methods
For model development, 50 patients with metastatic nodules were prospectively included. Two consecutive CT scans were performed to assess volumetry for 1,586 nodules. Nodule volume, surface voxel proportion (SVP), attachment proportion (AP) and absolute percentage error (APE) were calculated for each nodule and quantile regression analyses were performed to model the 95% percentile of APE. For validation, 41 patients who underwent metastasectomy were included. After volumetry of resected nodules, sensitivity and specificity for diagnosis of metastatic nodules were compared between two different thresholds of nodule growth determination: uniform 25% volume change threshold and individualized threshold calculated from the model (estimated 95% percentile APE).Results
SVP and AP were included in the final model: Estimated 95% percentile APE?=?37.82?·?SVP?+?48.60?·?AP-10.87. In the validation session, the individualized threshold showed significantly higher sensitivity for diagnosis of metastatic nodules than the uniform 25% threshold (75.0% vs. 66.0%, P?=?0.004)Conclusion
Estimated 95% percentile APE as an individualized threshold of nodule growth showed greater sensitivity in diagnosing metastatic nodules than a global 25% threshold.Key Points
? The 95?% percentile APE of a particular nodule can be predicted.? Estimated 95?% percentile APE can be utilized as an individualized threshold.? More sensitive diagnosis of metastasis can be made with an individualized threshold.? Tailored nodule management can be provided during nodule growth follow-up.19.
Objectives
Metal artefacts can impair accurate diagnosis of haemorrhage using flat detector CT (FD-CT), especially after aneurysm coiling. Within this work we evaluate a prototype metal artefact reduction algorithm by comparison of the artefact-reduced and the non-artefact-reduced FD-CT images to pre-treatment FD-CT and multi-slice CT images.Methods
Twenty-five patients with acute aneurysmal subarachnoid haemorrhage (SAH) were selected retrospectively. FD-CT and multi-slice CT before endovascular treatment as well as FD-CT data sets after treatment were available for all patients. The algorithm was applied to post-treatment FD-CT. The effect of the algorithm was evaluated utilizing the pre-post concordance of a modified Fisher score, a subjective image quality assessment, the range of the Hounsfield units within three ROIs, and the pre-post slice-wise Pearson correlation.Results
The pre-post concordance of the modified Fisher score, the subjective image quality, and the pre-post correlation of the ranges of the Hounsfield units were significantly higher for artefact-reduced than for non-artefact-reduced images. Within the metal-affected slices, the pre-post slice-wise Pearson correlation coefficient was higher for artefact-reduced than for non-artefact-reduced images.Conclusion
The overall diagnostic quality of the artefact-reduced images was improved and reached the level of the pre-interventional FD-CT images. The metal-unaffected parts of the image were not modified.Key Points
? After coiling subarachnoid haemorrhage, metal artefacts seriously reduce FD-CT image quality.? This new metal artefact reduction algorithm is feasible for flat-detector CT.? After coiling, MAR is necessary for diagnostic quality of affected slices.? Slice-wise Pearson correlation is introduced to evaluate improvement of MAR in future studies.? Metal-unaffected parts of image are not modified by this MAR algorithm.20.