Publications by authors named "Elisabeth Appel"

T1-weighted black blood FS sequences may provide a useful addition to imaging protocols in detection of subtle changes in venous vasculitides and, therefore, may have an impact on treatment options.

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Although iso-centric patient positioning is enormously important in computed tomography (CT), it is complicated in thoracoabdominal imaging by the varying dimensions of the body. Patient positioning can affect the appearance of the patient on the localiser. Positioned too close to the x-ray tube, a patient appears considerably more voluminous.

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Background: Patients with interatrial shunts (patient foramen ovale/atrial septal defect) are potentially at increased risk for paradoxical air embolism following computed tomography (CT) scans with intravenous (IV) contrast media injection. IV in-line filters aim to prevent such embolisms but are not compatible with power injection required for diagnostic CT.

Purpose: The purpose of this study was to determine whether the incidence of paradoxical embolism to the heart and brain in patients with an interatrial shunt is higher compared with controls within 48 hours following injection of IV contrast media without IV in-line filter.

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Purpose: To assess whether it is possible to reliably detect patients with strong suspicion of COVID-19 despite initially negative quantitative polymerase-chain-reaction (qPCR) tests by means of computed tomography (CT).

Materials And Methods: 437 patients with suspected COVID-19 but initially negative qPCR and subsequent chest CT between March 13 and November 30, 2020 were included in this retrospective study. CT findings were compared to results of successive qPCR tests (minimum of 3 qPCR tests if CT suggested infection) to determine the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CT for diagnosing COVID-19.

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Purpose: Classifications were created to facilitate radiological evaluation of the novel coronavirus disease 2019 (COVID-19) on computed tomography (CT) images. The categorical CT assessment scheme (CO-RADS) categorizes lung parenchymal changes according to their likelihood of being caused by SARS-CoV-2 infection. This study investigates the diagnostic accuracy of diagnosing COVID-19 with CO-RADS compared to the Thoracic Imaging Section of the German Radiological Society (DRG) classification and Radiological Society of North America (RSNA) classification in an anonymized patient cohort.

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Objective: To assess accuracy of dual-energy computed tomography (DECT) to differentiate uric acid from calcium urinary stones in dual-energy split filter sequential-spiral dual-source acquisition.

Methods: Thirty-four urinary stones (volume 89.0 ± 77.

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Objective: To determine safety of shortened observation time without follow-up chest x-ray (CXR) after CT-guided transthoracic procedures (lung biopsy or fiducial placement) in patients without immediate postprocedural pneumothorax (PTX).

Methods: Consecutive patients that underwent CT-guided procedures between January 5, 2015, and June 19, 2017, were included in this retrospective institutional review board-approved HIPAA-compliant study. Data regarding postprocedural course, complications, and clinical follow-up of the patients were obtained through a review of electronic medical records.

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Article Synopsis
  • The study aims to evaluate how accurately CT scans diagnose porcelain gallbladder and determine the clinical outcomes for those patients.
  • A total of 133 CT scans were reviewed, with a 68% confirmation rate for porcelain gallbladder diagnosis, while 32% were false positives, primarily due to issues like stones or sludge.
  • Despite 6% of patients having concurrent gallbladder cancer at diagnosis, none developed cancer during an average follow-up of 6.6 years, highlighting the need for careful assessment when diagnosing porcelain gallbladder on CT.
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Background: Motion correction is mandatory for the functional Fourier decomposition magnetic resonance imaging (FD-MRI) of the lungs. Therefore, it is important to evaluate the quality of various image-registration algorithms for pulmonary FD-MRI and to determine their impact on FD-MRI outcome.

Purpose: To evaluate different image-registration algorithms for FD-MRI in functional lung imaging.

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Objectives: The detection of Coronavirus Disease 2019 (COVID-19) by reverse transcription polymerase chain reaction (RT-PCR) has varying sensitivity. Computed tomography (CT) of the chest can verify infection in patients with clinical symptoms and a negative test result, accelerating treatment and actions to prevent further contagion. However, CT employs ionising radiation.

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Objectives: To evaluate the impact of patient positioning during CT-guided lung biopsy on patients' outcomes.

Methods: In this retrospective, IRB-approved, HIPAA-compliant study, consecutive CT-guided lung biopsies performed on 5/1/2015-12/26/2017 were included. Correlation between incidence of pneumothorax, chest tube placement, pulmonary bleeding with patient, and procedure characteristics was evaluated.

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Objective: To assess impact of single-energy metal artifact reduction (SEMAR) algorithm utilizing retrospective adaptive thresholding in reducing metal artifacts in the abdomen and pelvis.

Methods: In this prospective institutional review board-approved, Health Insurance Portability and Accountability Act-compliant study, 90 patients with various metals (n = 97) on computed tomography of abdomen and pelvis (Canon Medical, Aquilion ONE and PRIME) scanned 07/2017-09/2018 with SEMAR retrospectively applied were included. Density was measured in the near and far field to the metals.

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Objectives: The aims of the study were to systematically analyze causes for radiation dose outliers in emergency department noncontrast head computed tomographies (CTs), to develop and implement standardized system solutions, and audit program success for an extended period of time.

Methods: This study was performed in a large, tertiary academic center between January 2015 and September 2017. Four phases of radiation dose data collection with and without prior interventions were performed.

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Objective: The objective of this study was to assess the impact of preprocedural time-out on workflow and patient safety in computed tomography (CT)-guided procedures.

Methods: In this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant study, preprocedure time-out was assessed by an independent observer in CT-guided procedures performed from January 16, 2018, to May 15, 2018. Anonymous survey of 302 radiology team members involved in image-guided procedures about preprocedure time-out was performed using REDCap.

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Purpose: To evaluate the technical and clinical success rates and safety of bilateral gelfoam uterine artery embolization (UAE) for symptomatic acquired uterine arteriovenous shunting due to prior obstetric or gynecologic event.

Materials And Methods: This was a retrospective study of consecutive patients of reproductive age who presented with abnormal uterine bleeding after recent gynecologic procedures or obstetric events between January 2013 and February 2018. Bilateral UAE was performed in all patients using gelfoam slurry.

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Rationale And Objectives: To generate institutional size-specific diagnostic reference levels (DRLs) for computed tomography angiography (CTA) examinations and assess the potential for dose optimization compared to size-independent DRLs.

Materials And Methods: CTA examinations of the aorta, the pulmonary arteries and of the pelvis/lower extremity performed between January 2016 and January 2017 were included in our retrospective study. Water equivalent diameter (Dw) was automatically calculated for each patient.

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Objectives: To evaluate machine learning (ML) to detect chest CT examinations with dose optimization potential for quality assurance in a retrospective, cross-sectional study.

Methods: Three thousand one hundred ninety-nine CT chest examinations were used for training and testing of the feed-forward, single hidden layer neural network (January 2016-December 2017, 60% male, 62 ± 15 years, 80/20 split). The model was optimized and trained to predict the volumetric computed tomography dose index (CTDI) based on scan patient metrics (scanner, study description, protocol, patient age, sex, and water-equivalent diameter (D)).

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Background: To evaluate the detection rate and image quality in CT-body-packer-screening at different radiation-dose levels and to determine a dose threshold that enables a reliable detection of incorporated body packs and incidental findings with a maximum of dose saving.

Materials And Methods: We retrospectively included 27 individuals who underwent an abdominal CT with automated exposure control due to suspected body packing. CT images were reconstructed at different radiation-dose levels of 50%, 10, 5% and 1% using iterative reconstructions.

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Rationale And Objectives: To use an automatic computed tomography (CT) dose monitoring system to analyze the institutional chest and abdominopelvic CT dose data as regards the updated 2017 American College of Radiology (ACR) diagnostic reference levels (DRLs) based on water-equivalent diameter (Dw) and size-specific dose estimates (SSDE) to detect patient-size subgroups in which CT dose can be optimized.

Materials And Methods: All chest CT examinations performed between July 2016 and April 2017 with and without contrast material, CT of the pulmonary arteries, and abdominopelvic CT with and without contrast material were included in this retrospective study. Dw and SSDE were automatically calculated for all scans using a previously validated in-house developed Matlab software and stored into our CT dose monitoring system.

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Size-specific institutional diagnostic reference levels (DRLs) were generated for chest and abdominopelvic computed tomography (CT) based on size-specific dose estimates (SSDEs) and depending on patients' water-equivalent diameter (Dw). 1690 CT examinations were included in the IRB-approved retrospective study. SSDEs based on the mean water-equivalent diameter of the entire scan volume were calculated automatically.

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