Publications by authors named "Daniel Overhoff"

24 Publications

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Prediction of cardiac events with non-contrast magnetic resonance feature tracking in patients with ischaemic cardiomyopathy.

ESC Heart Fail 2021 Nov 24. Epub 2021 Nov 24.

1st Department of Medicine, University Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, Heidelberg, D-68167, Germany.

Aims: The aim of this study was to evaluate the prognostic value of feature tracking (FT) derived cardiac magnetic resonance (CMR) strain parameters of the left ventricle (LV)/right ventricle (RV) in ischaemic cardiomyopathy (ICM) patients treated with an implantable cardioverter-defibrillator (ICD). Current guidelines suggest a LV-ejection fraction ≤35% as major criterion for ICD implantation in ICM, but this is a poor predictor for arrhythmic events. Supplementary parameters are missing.

Methods And Results: Ischaemic cardiomyopathy patients (n = 242), who underwent CMR imaging prior to primary and secondary implantation of ICD, were classified depending on EF ≤ 35% (n = 188) or >35% (n = 54). FT parameters were derived from steady-state free precession cine views using dedicated software. The primary endpoint was a composite of cardiovascular mortality (CVM) and/or appropriate ICD therapy. There were no significant differences in FT-function or LV-/RV-function parameters in patients with an EF ≤ 35% correlating to the primary endpoint. In patients with EF > 35%, standard CMR functional parameters, such as LV-EF, did not reveal significant differences. However, significant differences in most FT parameters correlating to the primary endpoint were observed in this subgroup. LV-GLS (left ventricular-global longitudinal strain) and RV-GRS (right ventricular-global radial strain) revealed the best diagnostic performance in ROC curve analysis. The combination of LV-GLS and RV-GRS showed a sensitivity of 85% and a specificity of 76% for the prediction of future events.

Conclusions: The impact of FT derived measurements in the risk stratification of patients with ICM depends on LV function. The combination of LV-GLS/RV-GRS seems to be a predictor of cardiovascular mortality and/or appropriate ICD therapy in patients with EF > 35%.
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http://dx.doi.org/10.1002/ehf2.13712DOI Listing
November 2021

Determination of Cochlear Duct Length With 3D Two-dimensional Methods: A Retrospective Clinical Study of Imaging by Computed Tomography and Cone Beam Computed Tomography.

In Vivo 2021 Nov-Dec;35(6):3339-3344

Department of Diagnostic and Interventional Radiology and Neuroradiology, Bundeswehr Central Hospital Koblenz, Koblenz, Germany.

Background: The aim of this study was to compare three different methods for measurement of cochlear duct length (CDL) in the clinical setting for two different imaging modalities, namely computed tomography (CT) and cone-beam computed tomography (CBCT).

Patients And Methods: One hundred temporal bone data sets (CT: n=50; CBCT: n=50) of non-malformed cochleae were retrospectively analyzed using three different CDL estimation techniques: 3D curved multiplanar reconstruction (cMPR), 2D cMPR and the A-value formula.

Results: The data sets belonged to 60 patients (34 males, 26 females; mean age=50.28±18.58 years). For both imaging modalities, application of the 3D cMPR estimation technique led to significantly greater mean CDL values than the two-dimensional methods (p<0.0083). The CDL measurements viewed in CT imaging software were significantly shorter than the corresponding CBCT measurements (p<0.05). Using a linear mixed model, differences in CDL by sex (p=0.796), age (p=0.377) and side of ear (p=0.690) were not significant.

Conclusion: The 3D cMPR technique was found to provide the most accurate in vivo CDL measurement in non-malformed cochlea in both CT and CBCT imaging compared to 2D methods. The study results also suggest that the higher spatial resolution in CBCT imaging results in more precise CDL determination than in CT.
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http://dx.doi.org/10.21873/invivo.12631DOI Listing
October 2021

Dual-Energy CT Vital Iodine Tumor Burden for Response Assessment in Patients With Metastatic GIST Undergoing TKI Therapy: Comparison to Standard CT and FDG PET/CT Criteria.

AJR Am J Roentgenol 2021 Oct 20. Epub 2021 Oct 20.

Department of Radiology, Duke University Medical Center, Durham, North Carolina, United States of America.

CT-based criteria for assessing gastroinstestinal stromal tumor (GIST) response to tyroskine kinase inhibitor (TKI) therapy are limited partly because tumor attenuation is influenced by treatment-related changes including hemorrhage and calcification. Iodine concentration may be less impacted by such changes. To determine whether DECT vital iodine tumor burden (TB) provides improved differentiation between responders and non-responders in patients with metastatic GIST undergoing TKI therapy compared to established CT and PET/CT criteria. An anthropomorphic phantom with spherical inserts mimicking GIST lesions of varying iodine concentrations and having non-enhancing central necrotic cores underwent DECT to determine a threshold iodine concentration. Forty patients (median age 57 years; 25 women, 15 men) treated with TKI for metaststic GIST were retrospectively evaluated. Patients underwent baseline and follow-up DECT and FDG PET/CT. Response assessment was performed using RECIST 1.1, modified Choi (mChoi), vascular tumor burden (VTB), DECT vital iodine TB, and European Organization for Research and Treatment of Cancer (EORTC PET) criteria. DECT vital iodine TB used the same percentage changes as RECIST 1.1 response categories. Progression-free survival (PFS) was compared between responders and non-responders for each response criteria using Cox proportional hazard ratios and Harrell's c-indices. The phantom experiment identified a 0.5 mg/mL threshold to differentiate vital from non-vital tissue. Using DECT vital iodine TB, median PFS was significantly different between non-responders and responders (587 vs 167 days, respectively; p=.02). Hazard ratio for progression for DECT vital iodine TB non-responders versus responders was 6.9, versus 7.6 for EORTC PET, 3.3 for VTB, 2.3 for RECIST 1.1, and 2.1 for mChoi. C-index was 0.74 for EORTC PET, 0.73 for DECT vital iodine TB, 0.67 for VTB, 0.61 for RECIST 1.1, and 0.58 for mChoi. C-index was significantly greater for DECT vital iodine TB than RECIST 1.1 (p=.02) and mChoi (p=.002), but not different than VTB and EORTC PET (p>.05). DECT vital iodine TB criteria showed comparable performance as EORTC PET and outperformed RECIST 1.1 and mChoi for response assessment of metastatic GIST under TKI therapy. DECT vital iodine TB could help guide early management decisions in patients on TKI therapy.
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http://dx.doi.org/10.2214/AJR.21.26636DOI Listing
October 2021

Detectability of Lung Nodules in Ultra-low Dose CT.

Anticancer Res 2021 Oct;41(10):5053-5058

Department of Radiology and Nuclear Medicine, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany

Background/aim: Investigation of the influence of different ultra-low dose computed tomography (ULDCT) protocols on the detection of solid and subsolid nodules in a phantom study.

Patients And Methods: A chest phantom with pulmonary nodules was scanned with different CT protocols ranging from ultra-low dose settings with spectral shaping to a standard low dose lung cancer screening protocol. Image analysis was performed with different reconstruction algorithms and dedicated computer aided detection (CAD), which was compared to manual readout.

Results: The highest sensitivity rates (83%) were achieved for the 90 mAs and 120 mAs protocols when reconstructed with ADMIRE 3 or 5 and manual readout. The only statistically significant difference was found for subsolid nodules with preference of manual readout compared to CAD (p<0.05). Dose levels for the mAs settings ranged from 0.029 to 0.2 mSv.

Conclusion: Reliable detectability rates for solid nodules were achieved; CAD software did not prove reliable for subsolid nodules.
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http://dx.doi.org/10.21873/anticanres.15320DOI Listing
October 2021

T2-weighted Imaging of the Breast at 1.5T Using Simultaneous Multi-slice Acceleration.

Anticancer Res 2021 Sep;41(9):4423-4429

Clinic of Radiology and Nuclear Medicine, University Medical Centre Mannheim, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.

Aim: To evaluate the image quality and time saving using simultaneous multi-slice (SMS)-accelerated T2-weighted turbo spin echo (TSE) sequences compared to standard T2 TSE sequences in breast magnetic resonance imaging (MRI).

Patients And Methods: Thirty patients were examined with an SMS-accelerated T2 TSE sequence and a standard T2 TSE sequence as part of a breast MRI protocol at 1.5T. Image quality, signal homogeneity and tissue delineation were evaluated. For quantitative assessment, the signal-to-noise ratio (SNR) was measured from representative SNR maps.

Results: There were no significant differences regarding tissue delineation and signal homogeneity. Image quality was rated equal at the chest wall and the breasts but decreased in the axilla on SMS-T2 TSE (p=0.01) with a simultaneous decrease of SNR (p=0.03). This did not significantly impact the overall image quality (p=0.2). The acquisition time for SMS-T2 TSE was 48% shorter compared to standard T2 TSE.

Conclusion: SMS-acceleration for T2-weighted imaging of the breast at 1.5T substantially reduces acquisition time while maintaining comparable quantitative and qualitative image quality. This may pave the way for protocol abbreviation especially in a high-throughput clinical workspace.
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http://dx.doi.org/10.21873/anticanres.15249DOI Listing
September 2021

Risk stratification of patients with Brugada syndrome: the impact of myocardial strain analysis using cardiac magnetic resonance feature tracking.

Hellenic J Cardiol 2021 Sep-Oct;62(5):329-338. Epub 2021 Jun 1.

First Department of Medicine, University Medical Centre Mannheim, Medical Faculty Mannheim, University of Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research) partner site Mannheim, Germany.

Objective: This study evaluated the prognostic significance of cardiac magnetic resonance myocardial feature tracking (CMR-FT) in patients with Brugada syndrome (BrS) to detect subclinical alterations and predict major adverse events (MAE).

Methods: CMR was performed in 106 patients with BrS and 25 healthy controls. Biventricular global strain analysis was assessed using CMR-FT. Patients were followed over a median of 11.6 [8.8 ± 13.8] years.

Results: The study cohort was subdivided according to the presence of a spontaneous type 1 ECG (sECG) into sBrS (BrS with sECG, n = 34 (32.1%)) and diBrS (BrS with drug-induced type 1 ECG, n = 72 (67.9%)). CMR-FT revealed morphological differences between sBrS and diBrS patients with regard to right ventricular (RV) strain (circumferential (%) (sBrS -7.9 ± 2.9 vs diBrS - 9.5 ± 3.1, p = 0.02) and radial (%) (sBrS 12.0 ± 4.3 vs diBrS 15.4 ± 5.4, p = 0.004)). During follow-up, MAE occurred in 11 patients (10.4%). Multivariable analysis was performed to identify independent predictors for the occurrence of events during follow-up. The strongest predictive value was found for RV circumferential strain (OR 3.2 (95% CI 1.4 - 6.9), p = 0.02) and RVOT/BSA (OR 3.1 (95% CI 1.0 - 7.0), p = 0.03).

Conclusions: Myocardial strain analysis detected early subclinical alterations, prior to apparent changes in myocardial function, in patients with BrS. While usual functional parameters were within the normal range, CMR-FT revealed pathological results in patients with an sECG. Moreover, RV circumferential strain and RVOT size provided additional prognostic information on the occurrence of MAE during follow-up, which reflects electrical vulnerability.
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http://dx.doi.org/10.1016/j.hjc.2021.05.003DOI Listing
November 2021

[The International Radiomics Platform - An Initiative of the German and Austrian Radiological Societies - First Application Examples].

Rofo 2021 Mar 22;193(3):e3. Epub 2021 Apr 22.

Department of Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany.

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http://dx.doi.org/10.1055/a-1475-0537DOI Listing
March 2021

Cost-Effectiveness Analysis of Ga DOTA-TATE PET/CT, In-Pentetreotide SPECT/CT and CT for Diagnostic Workup of Neuroendocrine Tumors.

Diagnostics (Basel) 2021 Feb 18;11(2). Epub 2021 Feb 18.

Department of Radiology, University Hospital, LMU Munich, Marchioninistr. 15, 81377 Munich, Germany.

Neuroendocrine tumors (NETs) are relatively rare neoplasms arising from the hormone-producing neuroendocrine system that can occur in various organs such as pancreas, small bowel, stomach and lung. As the majority of these tumors express somatostatin receptors (SSR) on their cell membrane, utilization of SSR analogs in nuclear medicine is a promising, but relatively costly approach for detection and localization. The aim of this study was to analyze the cost-effectiveness of Ga-DOTA-TATE PET/CT (Gallium-68 DOTA-TATE Positron emission tomography/computed tomography) compared to In-pentetreotide SPECT/CT (Indium-111 pentetreotide Single Photon emission computed tomography/computed tomography) and to CT (computed tomography) alone in detection of NETs. A decision model on the basis of Markov simulations evaluated lifetime costs and quality-adjusted life years (QALYs) related to either a CT, SPECT/CT or PET/CT. Model input parameters were obtained from publicized research projects. The analysis is grounded on the US healthcare system. Deterministic sensitivity analysis of diagnostic parameters and probabilistic sensitivity analysis predicated on a Monte Carlo simulation with 30,000 reiterations was executed. The willingness-to-pay (WTP) was determined to be $ 100,000/QALY. In the base-case investigation, PET/CT ended up with total costs of $88,003.07 with an efficacy of 4.179, whereas CT ended up with total costs of $88,894.71 with an efficacy of 4.165. SPECT/CT ended up with total costs of $89,973.34 with an efficacy of 4.158. Therefore, the strategies CT and SPECT/CT were dominated by PET/CT in the base-case scenario. In the sensitivity analyses, PET/CT remained a cost-effective strategy. This result was due to reduced therapy costs of timely detection. The additional costs of Ga-DOTA-TATE PET/CT when compared to CT alone are justified in the light of potential savings in therapy costs and better outcomes.
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http://dx.doi.org/10.3390/diagnostics11020334DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7922846PMC
February 2021

Extent of peri-infarct scar on late gadolinium enhancement cardiac magnetic resonance imaging and outcome in patients with ischemic cardiomyopathy.

Heart Rhythm 2021 06 28;18(6):954-961. Epub 2021 Jan 28.

Department of Medicine, University Medical Centre Mannheim, University of Heidelberg, Mannheim, Germany; DZHK (German Centre for Cardiovascular Research) partner site, Mannheim, Germany.

Background: Only a minority of patients who receive an implantable cardioverter-defibrillator (ICD) on the basis of left ventricular ejection fraction receive appropriate ICD therapy. Peri-infarct scar zone assessed by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) is a possible substrate for ventricular tachyarrhytmias (VTAs).

Objective: The aim of our prospective study was to determine whether LGE-CMR parameters can predict the occurrence of VTA in patients with ischemic cardiomyopathy (ICM).

Methods: Two hundred sixteen patients with ICM underwent CMR imaging before primary or secondary ICD implantation and were prospectively followed. We assessed CMR indices and CMR scar characteristics (infarct core and peri-infarct zone) to predict outcome and VTAs.

Results: Patients were followed up for 1497 days (interquartile range 697-2237 days). Forty-seven patients (21%) received appropriate therapy during follow-up. Patients with appropriate ICD therapy had smaller core scar (31.5% ± 8.5% vs 36.8% ± 8.9%; P = .0004) but larger peri-infarct scar (12.4% ± 2.6% vs 10.5% ± 2.9%; P = .0001) than did patients without appropriate therapy. In multivariate Cox regression analysis, peri-infarct scar (hazard ratio 1.15; 95% confidence interval 1.07-1.24; P = .0001) was independently and significantly associated with VTAs whereas left ventricular ejection fraction, right ventricular ejection fraction, core scar, and left atrial ejection fraction were not.

Conclusion: Scar extent of peri-infarct border zone was significantly associated with appropriate ICD therapy. Thus, LGE-CMR parameters can identify a subgroup of patients with ICM and an increased risk of life-threatening VTAs.
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http://dx.doi.org/10.1016/j.hrthm.2021.01.023DOI Listing
June 2021

The International Radiomics Platform - An Initiative of the German and Austrian Radiological Societies - First Application Examples.

Rofo 2021 Mar 26;193(3):276-288. Epub 2020 Nov 26.

Department of Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany.

Purpose:  The DRG-ÖRG IRP (Deutsche Röntgengesellschaft-Österreichische Röntgengesellschaft international radiomics platform) represents a web-/cloud-based radiomics platform based on a public-private partnership. It offers the possibility of data sharing, annotation, validation and certification in the field of artificial intelligence, radiomics analysis, and integrated diagnostics. In a first proof-of-concept study, automated myocardial segmentation and automated myocardial late gadolinum enhancement (LGE) detection using radiomic image features will be evaluated for myocarditis data sets.

Materials And Methods:  The DRG-ÖRP IRP can be used to create quality-assured, structured image data in combination with clinical data and subsequent integrated data analysis and is characterized by the following performance criteria: Possibility of using multicentric networked data, automatically calculated quality parameters, processing of annotation tasks, contour recognition using conventional and artificial intelligence methods and the possibility of targeted integration of algorithms. In a first study, a neural network pre-trained using cardiac CINE data sets was evaluated for segmentation of PSIR data sets. In a second step, radiomic features were applied for segmental detection of LGE of the same data sets, which were provided multicenter via the IRP.

Results:  First results show the advantages (data transparency, reliability, broad involvement of all members, continuous evolution as well as validation and certification) of this platform-based approach. In the proof-of-concept study, the neural network demonstrated a Dice coefficient of 0.813 compared to the expert's segmentation of the myocardium. In the segment-based myocardial LGE detection, the AUC was 0.73 and 0.79 after exclusion of segments with uncertain annotation.The evaluation and provision of the data takes place at the IRP, taking into account the FAT (fairness, accountability, transparency) and FAIR (findable, accessible, interoperable, reusable) criteria.

Conclusion:  It could be shown that the DRG-ÖRP IRP can be used as a crystallization point for the generation of further individual and joint projects. The execution of quantitative analyses with artificial intelligence methods is greatly facilitated by the platform approach of the DRG-ÖRP IRP, since pre-trained neural networks can be integrated and scientific groups can be networked.In a first proof-of-concept study on automated segmentation of the myocardium and automated myocardial LGE detection, these advantages were successfully applied.Our study shows that with the DRG-ÖRP IRP, strategic goals can be implemented in an interdisciplinary way, that concrete proof-of-concept examples can be demonstrated, and that a large number of individual and joint projects can be realized in a participatory way involving all groups.

Key Points:   · The DRG-ÖRG IRP is a web/cloud-based radiomics platform based on a public-private partnership.. · The DRG-ÖRG IRP can be used for the creation of quality-assured, structured image data in combination with clinical data and subsequent integrated data analysis.. · First results show the applicability of left ventricular myocardial segmentation using a neural network and segment-based LGE detection using radiomic image features.. · The DRG-ÖRG IRP offers the possibility of integrating pre-trained neural networks and networking of scientific groups..

Citation Format: · Overhoff D, Kohlmann P, Frydrychowicz A et al. The International Radiomics Platform - An Initiative of the German and Austrian Radiological Societies. Fortschr Röntgenstr 2021; 193: 276 - 287.
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http://dx.doi.org/10.1055/a-1244-2775DOI Listing
March 2021

A quantitative CT parameter for the assessment of pulmonary oedema in patients with acute respiratory distress syndrome.

PLoS One 2020 12;15(11):e0241590. Epub 2020 Nov 12.

Institute of Clinical Radiology and Nuclear Medicine, University Medical Centre Mannheim, Heidelberg University, Mannheim, Germany.

Objectives: The aim of this study was to establish quantitative CT (qCT) parameters for pathophysiological understanding and clinical use in patients with acute respiratory distress syndrome (ARDS). The most promising parameter is introduced.

Materials And Methods: 28 intubated patients with ARDS obtained a conventional CT scan in end-expiratory breathhold within the first 48 hours after admission to intensive care unit (ICU). Following manual segmentation, 137 volume- and lung weight-associated qCT parameters were correlated with 71 clinical parameters such as blood gases, applied ventilation pressures, pulse contour cardiac output measurements and established status and prognosis scores (SOFA, SAPS II).

Results: Of all examined qCT parameters, excess lung weight (ELW), i.e. the difference between a patient's current lung weight and the virtual lung weight of a healthy person at the same height, displayed the most significant results. ELW correlated significantly with the amount of inflated lung tissue [%] (p<0.0001; r = -0.66) and was closely associated with the amount of extravascular lung water (EVLW) (p<0.0001; r = 0.72). More substantially than the oxygenation index (PaO2/FiO2) or any other clinical parameter it correlated with the patients' mean SOFA- (p<0.0001, r = 0.69) and SAPS II-Score (p = 0.0005, r = 0.62). Patients who did not survive intensive care treatment displayed higher values of ELW in the initial CT scans.

Conclusions: ELW could serve as a non-invasive method to quantify the amount of pulmonary oedema. It might serve as an early radiological marker of severity in patients with ARDS.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0241590PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7660563PMC
December 2020

Contrast Saline Mixture DualFlow Injection Protocols for Low-Kilovolt Computed Tomography Angiography: A Systematic Phantom and Animal Study.

Invest Radiol 2020 12;55(12):785-791

Department of Diagnostic and Interventional Radiology, University Hospital Bonn, Rheinische-Friedrich-Wilhelms-Universität Bonn, North Rhine-Westphalia (NRW), Germany.

Objective: The aim of this study was to evaluate a contrast media (CM)-saline mixture administration with DualFlow (DF) to adapt injection protocols to low-kilovolt (kV) computed tomography angiography (CTA).

Materials And Methods: In both a circulation phantom and animal model (5 Goettingen minipigs), 3 injection protocols were compared in dynamic thoracic CTA: (a) DF injection protocol at 80 kV with a iodine delivery rate (IDR) of 0.9 gI/s, a flowrate of 5 mL/s injected with a 60%/40% ratio of iopromide (300 mgI/mL) and saline (dose contrast medium 180 mgI/kg body weight [BW]); (b) reference CTA was performed at 120 kV and a 40% higher iodine dose applied at higher IDR (1.5 gI/s, 5 mL/s iopromide [300 mgI/mL]; no simultaneously administered saline; 300 mgI/kg BW); and (c) conventional single-flow (SF) protocol with identical IDR as the DF protocol at 80 kV (0.9 gI/s, 3 mL/s iopromide [300 mgI/mL]; no simultaneously administered saline; 180 mgI/kg BW). All 3 injection protocols are followed by a saline chaser applied at the same flow rate as the corresponding CM injection. Time attenuation curves representing the vascular bolus shape were generated for pulmonary trunk and descending aorta.

Results: In the circulation phantom, pulmonary and aortic time attenuation curves for the 80 kV DF injection protocols do not significantly differ from the 80 kV SF and the 120 kV SF reference. In the animal model, the 80 kV DF protocol shows similar pulmonal and aortic peak enhancement when compared with the 120 kV SF and 80 kV SF protocols. Also, the bolus length above an attenuation level of 300 HU reveals no significant differences between injection protocols. However, the time to peak was significantly shorter for the 80 kV DF when compared with the 80 kV SF protocol (15.78 ± 1.9 seconds vs 18.24 ± 2.0 seconds; P = 0.008).

Conclusion: DualFlow injection protocols can be tailored for low-kV CTA by reducing the IDR while overall flow rate remains unchanged. Although no differences in attenuation were found, DF injections offer a shorter time to peak closer to the reference 120 kV protocol.This allows the use of DF injection protocols to calibrate bolus density in low-kV CTA and yields the potential for a more individualized CM administration.
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http://dx.doi.org/10.1097/RLI.0000000000000706DOI Listing
December 2020

The Nipple as a Landmark for Needle Decompression of Tension Pneumothorax in Children - A CT-Based Evaluation and Proposal of an Alternative Insertion Site.

Prehosp Emerg Care 2021 Nov-Dec;25(6):747-752. Epub 2020 Nov 3.

Objective: Needle decompression of tension pneumothorax in children is a rarely encountered but potentially life-saving procedure, that is accompanied by a certain risk of injury. We evaluated the nipple as a landmark for an alternative anterior insertion site and as an aid in localizing lateral insertion sites, as well as its influence on the safety profile of the procedure.

Methods: In thoracic computer tomography scans of children aged 0-10 years, the distance to the closest vital structure was compared between the traditional anterior insertion site (2nd intercostal space midclavicular line) and an alternative anterior insertion site (2nd intercostal space at the nipple line). Furthermore, the level of the nipple at the midaxillary line was investigated as guidance in quickly localizing the lateral insertion site and ensuring an insertion site high enough to avoid intraabdominal injury by the decompression needle. Additionally, correlation of these measures with age was investigated.

Results: The distance to the closest vital structure at the 2nd intercostal space was significantly bigger at the nipple line compared to the midclavicular line (right: 2.23 ± 1.13 cm vs. 0.99 ± 0.80 cm, p < 0.0001; left: 1.92 ± 1.19 cm vs. 0.81 ± 0.70 cm, p < 0.0001). At the midaxillary line, the level of the nipple was at the 4th or 5th intercostal space in the majority of children (right: 83.8%; left: 88.1%). The mean distance from the nipple to the diaphragmatic cupola was 2.63 ± 1.85 cm on the right and 3.40 ± 1.86 cm on the left hemithorax.

Conclusion: When performing anterior needle decompression in children, we recommend inserting the needle at the more lateral insertion site at the 2nd intercostal space at the nipple line. At the lateral decompression sites, the nipple can be used as a marker for localizing the correct intercostal space for insertion and thereby ensuring enough caudad distance to the diaphragm to avoid abdominal injury.
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http://dx.doi.org/10.1080/10903127.2020.1831670DOI Listing
November 2020

Contrast-Enhanced Ultrasound (CEUS) for Follow-Up of Bosniak 2F Complex Renal Cystic Lesions-A 12-Year Retrospective Study in a Specialized European Center.

Cancers (Basel) 2020 Aug 4;12(8). Epub 2020 Aug 4.

Department of Radiology, University Hospital LMU, Marchioninistrasse 15, 81377 Munich, Germany.

Bosniak 2F renal cystic lesions feature morphologic characteristics between Bosniak I and III categories, the majority of which remain benign. However, a minor part of Bosniak 2F lesions may progress to malignancy. The purpose of this study was to assess Bosniak 2F cystic lesions during follow-up examinations by CEUS. One-hundred-and-twelve out of 364 patients with Bosniak 2F lesions underwent follow-up CEUS examinations between February 2008 and February 2020. Twelve out of 364 patients underwent renal surgery without follow-up CEUS. The progression rate of Bosniak 2F renal lesions detected by CEUS accounted for 7.1% (8/112 patients) after a mean of 12.9 months. The first follow-up CEUS revealed 75% of progressions (6/8), the remaining 25% (2/8) of progressions were detected during second follow-up CEUS. Underlying clear-cell renal cell carcinoma was histopathologically validated in 5/8 progressive complex cystic renal lesions. Stable sonomorphologic features were observed in 92.1% (104/112 patients). CEUS depicts a promising diagnostic imaging modality in the diagnostic work-up and follow-up of complex renal cystic lesions at higher spatial and temporal resolutions than CT or MRI. Its excellent safety profile, its easy and repeatable accessibility, and low financial costs render CEUS an attractive and powerful alternative imaging tool for monitoring complex renal cystic lesions.
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http://dx.doi.org/10.3390/cancers12082170DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7465614PMC
August 2020

Acute pulmonary embolism mimicking COVID - 19 pneumonia.

Int J Infect Dis 2020 07 18;96:475-476. Epub 2020 May 18.

Department of Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Baden-Württemberg, D-68167, Germany.

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http://dx.doi.org/10.1016/j.ijid.2020.05.053DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7233210PMC
July 2020

Radiation dose of chaperones during common pediatric computed tomography examinations.

Pediatr Radiol 2020 07 15;50(8):1078-1082. Epub 2020 May 15.

Clinic of Diagnostic and Interventional Radiology, Saarland University Medical Center, Kirrberger Straße - Gebäude 50.1, Homburg, 66421, Germany.

Background: One main challenge in pediatric imaging is to reduce motion artifacts by calming young patients. To that end, the Radiological Society of North America (RSNA) as early as 1997 stated the necessity of adults accompanying their child during the child's examination. Nonetheless, current research lacks data regarding radiation dose to these chaperones.

Objective: The aim of this study was to measure the radiation dose of accompanying adults during state-of-the-art pediatric CT protocols.

Materials And Methods: In addition to a 100-kV non-contrast-enhanced chest CT (Protocol 1), we performed a 70-kV contrast-enhanced chest protocol (Protocol 2) using a third-generation dual-source CT. We acquired data on the radiation dose around the scanner using digital dosimetry placed right at the gantry, 1 m away, as well as beside the gantry. We acquired the CT-surrounding radiation dose during scanning of a pediatric phantom as well as 12 pediatric patients.

Results: After conducting 10 consecutive phantom scans using Protocol 1, we found the location with the highest cumulative dose acquired was right next to the gantry opening, at 3 μSv. Protocol 2 showed highest cumulative dose of 2 μSv at the same location. For Protocol 1, the location with the highest radiation doses during pediatric scans was right next to the gantry opening, with doses of 0.75±0.70 μSv. For Protocol 2, the highest radiation was measured 1 m away at 0.50±0.60 μSv. No radiation dose was measured at any time beside the gantry.

Conclusion: Our results provide proof that chaperones receive low radiation doses during state-of-the-art CT examinations. Given knowledge of these values as well as the optimal spots with the lowest radiation doses, parents as well as patients might be more relaxed during the examination.
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http://dx.doi.org/10.1007/s00247-020-04681-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7329757PMC
July 2020

Prognostic Value of Coronary Computed Tomography Angiography-derived Morphologic and Quantitative Plaque Markers Using Semiautomated Plaque Software.

J Thorac Imaging 2021 Mar;36(2):108-115

Institute of Clinical Radiology and Nuclear Medicine, Faculty of Medicine Mannheim.

Purpose: In this study, we analyzed the prognostic value of coronary computed tomography angiography-derived morphologic and quantitative plaque markers and plaque scores for major adverse cardiovascular events (MACEs).

Materials And Methods: We analyzed the data of patients with suspected coronary artery disease (CAD). Various plaque markers were obtained using a semiautomated software prototype or derived from the results of the software analysis. Several risk scores were calculated, and follow-up data concerning MACE were collected from all patients.

Results: A total of 131 patients (65±12 y, 73% male) were included in our study. MACE occurred in 11 patients within the follow-up period of 34±25 months.CAD-Reporting and Data System score (odds ratio [OR]=11.62), SYNTAX score (SS) (OR=1.11), Leiden-risk score (OR=1.37), segment involvement score (OR=1.76), total plaque volume (OR=1.20), and percentage aggregated plaque volume (OR=1.32) were significant predictors for MACE (all P≤0.05). Moreover, the difference of the corrected coronary opacification (ΔCCO) correlated significantly with the occurrence of MACE (P<0.0001). The CAD-Reporting and Data System score, SS, and Leiden-risk score showed substantial sensitivity for predicting MACE (90.9%). The SS and Leiden-risk score displayed high specificities of 80.8% and 77.5%, respectively. These plaque markers and risk scores all provided high negative predictive value (>90%).

Conclusion: The coronary computed tomography angiography-derived plaque markers of segment involvement score, total plaque volume, percentage aggregated plaque volume, and ΔCCO, and the risk scores exhibited predictive value for the occurrence of MACE and can likely aid in identifying patients at risk for future cardiac events.
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http://dx.doi.org/10.1097/RTI.0000000000000509DOI Listing
March 2021

Extent of Late Gadolinium Enhancement Predicts Thromboembolic Events in Patients With Hypertrophic Cardiomyopathy.

Circ J 2020 04 1;84(5):754-762. Epub 2020 Apr 1.

1st Department of Medicine Cardiology, University Medical Center Mannheim, Medical Faculty Mannheim, University of Heidelberg.

Background: Thromboembolic complications such as ischemic stroke or peripheral arterial thromboembolism are known complications in hypertrophic cardiomyopathy (HCM). We sought to assess the clinical and cardiovascular magnetic resonance (CMR) characteristics of patients with HCM suffering from thromboembolic events and analyzed the predictors of these unfavorable outcomes.Methods and Results:The 115 HCM patients underwent late gadolinium enhanced (LGE) CMR and were included in the study. Follow-up was 5.6±3.6 years. The primary endpoint was the occurrence of thromboembolic events (ischemic stroke or peripheral arterial thromboembolism). It occurred in 17 (14.8%) patients (event group, EG), of whom 64.7% (11) were men. During follow-up, 10 (8.7%) patients died. Patients in the EG showed more comorbidities, such as heart failure (EG 41.2% vs. NEG (non-event group) 14.3%, P<0.01) and atrial fibrillation (AF: EG 70.6% vs. NEG 36.7%, P<0.01). Left atrial end-diastolic volume was significantly higher in the EG (EG 73±24 vs. NEG 50±33 mL/m, P<0.01). Both the presence and extent of LGE were enhanced in the EG (extent% EG 23±15% vs. NEG 8±9%, P<0.0001). No patient without LGE experienced a thromboembolic event. Multivariate analysis revealed AF and LGE extent as independent predictors.

Conclusions: LGE extent (>14.4%) is an independent predictor for thromboembolic complications in patients with HCM and might therefore be considered as an important risk marker. The risk for thromboembolic events is significantly elevated if accompanied by AF.
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http://dx.doi.org/10.1253/circj.CJ-19-0936DOI Listing
April 2020

Comparison of Machine Learning Computed Tomography-Based Fractional Flow Reserve and Coronary CT Angiography-Derived Plaque Characteristics with Invasive Resting Full-Cycle Ratio.

J Clin Med 2020 Mar 6;9(3). Epub 2020 Mar 6.

First Department of Medicine-Cardiology, University Medical Centre Mannheim, and DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Mannheim 68167, Germany.

Background: The aim is to compare the machine learning-based coronary-computed tomography fractional flow reserve (CT-FFR) and coronary-computed tomographic morphological plaque characteristics with the resting full-cycle ratio (RFR) as a novel invasive resting pressure-wire index for detecting hemodynamically significant coronary artery stenosis.

Methods: In our single center study, patients with coronary artery disease (CAD) who had a clinically indicated coronary computed tomography angiography (cCTA) and subsequent invasive coronary angiography (ICA) with pressure wire-measurement were included. On-site prototype CT-FFR software and on-site CT-plaque software were used to calculate the hemodynamic relevance of coronary stenosis.

Results: We enrolled 33 patients (70% male, mean age 68 ± 12 years). On a per-lesion basis, the area under the receiver operating characteristic curve (AUC) of CT-FFR (0.90) was higher than the AUCs of the morphological plaque characteristics length/minimal luminal diameter (LL/MLD; 0.80), minimal luminal diameter (MLD; 0.77), remodeling index (RI; 0.76), degree of luminal diameter stenosis (0.75), and minimal luminal area (MLA; 0.75).

Conclusion: CT-FFR and morphological plaque characteristics show a significant correlation to detected hemodynamically significant coronary stenosis. Whole CT-FFR had the best discriminatory power, using RFR as the reference standard.
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http://dx.doi.org/10.3390/jcm9030714DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7141220PMC
March 2020

Additional Value of Machine-Learning Computed Tomographic Angiography-Based Fractional Flow Reserve Compared to Standard Computed Tomographic Angiography.

J Clin Med 2020 Mar 3;9(3). Epub 2020 Mar 3.

First Department of Medicine-Cardiology, University Medical Centre Mannheim, Mannheim, Germany, DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Mannheim, Germany and ECAS (European Center for Angioscience), Faculty of Medicine Mannheim, Heidelberg University, 68167 Mannheim, Germany.

Machine-learning-based computed-tomography-derived fractional flow reserve (CT-FFR) obtains a hemodynamic index in coronary arteries. We examined whether it could reduce the number of invasive coronary angiographies (ICA) showing no obstructive lesions. We further compared CT-FFR-derived measurements to clinical and CT-derived scores. We retrospectively selected 88 patients (63 ± 11years, 74% male) with chronic coronary syndrome (CCS) who underwent clinically indicated coronary computed tomography angiography (cCTA) and ICA. cCTA image data were processed with an on-site prototype CT-FFR software. CT-FFR revealed an index of >0.80 in coronary vessels of 48 (55%) patients. This finding was corroborated in 45 (94%) patients by ICA, yet three (6%) received revascularization. In patients with an index ≤ 0.80, three (8%) of 40 were identified as false positive. A total of 48 (55%) patients could have been retained from ICA. CT-FFR (AUC = 0.96, ≤ 0.0001) demonstrated a higher diagnostic accuracy compared to the pretest probability or CT-derived scores and showed an excellent sensitivity (93%), specificity (94%), positive predictive value (PPV; 93%) and negative predictive value (NPV; 94%). CT-FFR could be beneficial for clinical practice, as it may identify patients with CAD without hemodynamical significant stenosis, and may thus reduce the rate of ICA without necessity for coronary intervention.
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http://dx.doi.org/10.3390/jcm9030676DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7141259PMC
March 2020

Coronary CT angiography derived plaque markers correlated with invasive instantaneous flow reserve for detecting hemodynamically significant coronary stenoses.

Eur J Radiol 2020 Jan 20;122:108744. Epub 2019 Nov 20.

Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Faculty of Medicine Mannheim, Heidelberg University, Germany.

Purpose: The study aimed to compare morphological and anatomic plaque markers derived from coronary computed tomography angiography (cCTA) for the detection of lesion specific ischemia with invasive instantaneous wave free ratio (iFR®) as the reference standard.

Methods: In our prospective study, we enrolled patients with suspected coronary artery disease (CAD), who had undergone cCTA, using a low-dose third-generation dual-source CT and invasive coronary angiography (ICA) with iFR® measurement. Various plaque markers were assessed on cCTA. Discriminatory power of these markers for the detection of ischemia-inducing coronary artery disease was evaluated against invasive iFR®.

Results: Our study cohort included 39 patients (66.6 ± 12.0 years, 72 % male). Among 54 vessel-specific lesions, 15 lesions (28 %) were characterized as hemodynamically significant by iFR® ≤0.89. The area under the curve (AUC) of lesion length/ minimal luminal diameter (LL/MLD) (0.84) was greater than the AUC of minimal luminal area (MLA) (0.82), MLD (0.81), the degree of luminal diameter stenosis (0.81), corrected coronary opacification (CCO) (0.79), remodeling index (RI) (0.75), and percentage aggregate plaque volume (%APV) (0.72). LL, vessel volume (VV), total plaque volume (TPV), calcified and non-calcified plaque volume (CPV and NCPV) did not reach statistical significance and were unable to discriminate between vessels with and without ischemia-inducing coronary stenosis.

Conclusion: LL/MLD, MLA, MLD, the degree of luminal diameter stenosis, CCO, RI, and %APV derived from cCTA can support the detection of hemodynamically significant coronary stenosis as compared with iFR®, with LL/MLD showing the greatest discriminatory power.
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http://dx.doi.org/10.1016/j.ejrad.2019.108744DOI Listing
January 2020

Correlation of machine learning computed tomography-based fractional flow reserve with instantaneous wave free ratio to detect hemodynamically significant coronary stenosis.

Clin Res Cardiol 2020 Jun 29;109(6):735-745. Epub 2019 Oct 29.

First Department of Medicine-Cardiology, University Medical Centre Mannheim, Mannheim, Germany.

Background: Fractional flow reserve based on coronary CT angiography (CT-FFR) is gaining importance for non-invasive hemodynamic assessment of coronary artery disease (CAD). We evaluated the on-site CT-FFR with a machine learning algorithm (CT-FFR) for the detection of hemodynamically significant coronary artery stenosis in comparison to the invasive reference standard of instantaneous wave free ratio (iFR).

Methods: This study evaluated patients with CAD who had a clinically indicated coronary computed tomography angiography (cCTA) and underwent invasive coronary angiography (ICA) with iFR-measurements. Standard cCTA studies were acquired with third-generation dual-source computed tomography and analyzed with on-site prototype CT-FFR software.

Results: We enrolled 40 patients (73% males, mean age 67 ± 12 years) who had iFR-measurement and CT-FFR calculation. The mean calculation time of CT-FFR values was 11 ± 2 min. The CT-FFR algorithm showed, on per-patient and per-lesion level, respectively, a sensitivity of 92% (95% CI 64-99%) and 87% (95% CI 59-98%), a specificity of 96% (95% CI 81-99%) and 95% (95% CI 84-99%), a positive predictive value of 92% (95% CI 64-99%), and 87% (95% CI 59-98%), and a negative predictive value of 96% (95% CI 81-99%) and 95% (95% CI 84-99%). The area under the receiver operating characteristic curve for CT-FFR on per-lesion level was 0.97 (95% CI 0.91-1.00). Per lesion, the Pearson's correlation between the CT-FFR and iFR showed a strong correlation of r = 0.82 (p < 0.0001; 95% CI 0.715-0.920).

Conclusion: On-site CT-FFR correlated well with the invasive reference standard of iFR and allowed for the non-invasive detection of hemodynamically significant coronary stenosis.
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http://dx.doi.org/10.1007/s00392-019-01562-3DOI Listing
June 2020

Peripheral Vascular Anomalies - Essentials in Periinterventional Imaging.

Rofo 2020 Feb 17;192(2):150-162. Epub 2019 Oct 17.

Department for Radiology, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany.

Background:  Peripheral vascular anomalies represent a rare disease with an underlying congenital mesenchymal and angiogenetic disorder. Vascular anomalies are subdivided into vascular tumors and vascular malformations. Both entities include characteristic features and flow dynamics. Symptoms can occur in infancy and adulthood. Vascular anomalies may be accompanied by characteristic clinical findings which facilitate disease classification. The role of periinterventional imaging is to confirm the clinically suspected diagnosis, taking into account the extent and location of the vascular anomaly for the purpose of treatment planning.

Method:  In accordance with the International Society for the Study of Vascular Anomalies (ISSVA), vascular anomalies are mainly categorized as slow-flow and fast-flow lesions. Based on the diagnosis and flow dynamics of the vascular anomaly, the recommended periinterventional imaging is described, ranging from ultrasonography and plain radiography to dedicated ultrafast CT and MRI protocols, percutaneous phlebography and transcatheter angiography. Each vascular anomaly requires dedicated imaging. Differentiation between slow-flow and fast-flow vascular anomalies facilitates selection of the appropriate imaging modality or a combination of diagnostic tools.

Results:  Slow-flow congenital vascular anomalies mainly include venous and lymphatic or combined malformations. Ultrasound and MRI and especially MR-venography are essential for periinterventional imaging. Arteriovenous malformations are fast-flow vascular anomalies. They should be imaged with dedicated MR protocols, especially when extensive. CT with 4D perfusion imaging as well as time-resolved 3D MR-A allow multiplanar perfusion-based assessment of the multiple arterial inflow and venous drainage vessels of arterio-venous malformations. These imaging tools should be subject to intervention planning, as they can reduce procedure time significantly. Fast-flow vascular tumors like hemangiomas should be worked up with ultrasound, including color-coded duplex sonography, MRI and transcatheter angiography in case of a therapeutic approach. In combined malformation syndromes, radiological imaging has to be adapted according to the dominant underlying vessels and their flow dynamics.

Conclusion:  Guide to evaluation of flow dynamics in peripheral vascular anomalies, involving vascular malformations and vascular tumors with the intention to facilitate selection of periinterventional imaging modalities and diagnostic and therapeutic approach to vascular anomalies.

Key Points:   · Peripheral vascular anomalies include vascular malformations and vascular tumors. Both entities represent a rare disease with an underlying congenital mesenchymal or angiogenetic disorder. · The role of periinterventional imaging is confirmation of the diagnosis by assessing the flow dynamics of the vascular anomaly. · Slow-flow congenital vascular anomalies include venous, lymphatic and venolymphatic malformations. Arteriovenous malformations are fast-flow vascular anomalies, whereas hemangiomas are fast-flow vascular tumors that are frequently associated with fast-flow arteriovenous shunts. The periinterventional imaging modalities of choice include dedicated MR protocols and CT with 4D perfusion imaging as well as invasive transcatheter angiography..

Citation Format: · Sadick M, Overhoff D, Baessler B et al. Peripheral Vascular Anomalies - Essentials in Periinterventional Imaging. Fortschr Röntgenstr 2020; 192: 150 - 162.
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http://dx.doi.org/10.1055/a-0998-4300DOI Listing
February 2020

Determining optimal needle size for decompression of tension pneumothorax in children - a CT-based study.

Scand J Trauma Resusc Emerg Med 2019 Oct 11;27(1):90. Epub 2019 Oct 11.

Department of Anaesthesiology and Intensive Care Medicine, University Medical Center Mannheim, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.

Background: For neonates and children requiring decompression of tension pneumothorax, specific recommendations for the choice of needle type and size are missing. The aim of this retrospective study was to determine optimal length and diameter of needles for decompression of tension pneumothorax in paediatric patients.

Methods: Utilizing computed tomography, we determined optimal length and diameter of needles to enable successful decompression and at the same time minimize risk of injury to intrathoracic structures and the intercostal vessels and nerve. Preexisting computed tomography scans of the chest were reviewed in children aged 0, 5 and 10 years. Chest wall thickness and width of the intercostal space were measured at the 4th intercostal space at the anterior axillary line (AAL) on both sides of the thorax. In each age group, three needles different in bore and length were evaluated regarding sufficient length for decompression and risk of injury to intrathoracic organs and the intercostal vessels and nerve.

Results: 197 CT-scans were reviewed, of which 58 were excluded, resulting in a study population of 139 children and 278 measurements. Width of the intercostal space was small at 4th ICS AAL (0 years: 0.44 ± 0.13 cm; 5 years: 0.78 ± 0.22 cm; 10 years: 1.12 ± 0.36 cm). The ratio of decompression failure to risk of injury at 4th ICS AAL was most favourable for a 22G/2.5 cm catheter in infants (Decompression failure: right: 2%, left: 4%, Risk of injury: right: 14%, left: 24%), a 22G/2.5 cm or a 20G/3.2 cm catheter in 5-year-old children (20G/3.2 cm: Decompression failure: right: 2.1%, left: 0%, Risk of injury: right: 2.1%, left: 17%) and a 18G/4.5 cm needle in 10-year-old children (Decompression failure: right: 9.5%, left: 9.5%, Risk of injury: right: 7.1%, left: 11.9%).

Conclusions: In children aged 0, 5 and 10 years presenting with a tension pneumothorax, we recommend 22G/2.5 cm, 20G/3.2 cm and 18G/4.5 cm needles, respectively, for acute decompression.
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http://dx.doi.org/10.1186/s13049-019-0671-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6788035PMC
October 2019
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