Publications by authors named "Ryan Dolan"

Purpose: We assessed the impact of bicuspid aortic valve (BAV), aortic stenosis (AS), and regurgitation (AR) on the metrics of left ventricular (LV) remodeling, as measured by electrocardiogram (ECG), transthoracic echocardiography (TTE), and cardiac magnetic resonance (CMR).

Methods: This retrospective CMR study included 11 patients with both AS and AR (BAV-ASR), 30 with AS (BAV-AS), 28 with AR (BAV-AR), 47 with neither AS nor AR (BAV-no_AS/AR), and 40 with trileaflet aortic valve (TAV-no_AS/AR). CMR analysis included the LV end-diastolic volume index (LVEDVi), mass index (LVMi), and extracellular volume fraction (ECV).

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Rationale And Objectives: Cardiac magnetic resonance imaging (CMR) is commonly obtained to evaluate for myocardial infiltrative disorders and fibrosis. Pre- and post-Gadolinium contrast T1-mapping sequences are employed to estimate interstitial expansion using extracellular volume fraction (ECV). Given the proximity of the liver to the heart, T1 and ECV quantification of the liver is feasible on CMR.

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Article Synopsis
  • The first year of radiology residency is challenging, requiring adjustments to a new field and preparing for on-call duties.
  • Implementing a longitudinal lecture series can enhance first-year residents' knowledge and confidence, benefiting the entire program.
  • This article details the creation of a resident-led lecture series focused on essential topics like rotation logistics, basic physics, exam protocols, and critical pathologies.
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Rationale And Objectives: Historically, patients undergoing image-guided percutaneous gastrostomy tube placement have been admitted overnight with feeds commencing 12-24 hours postprocedure. With new expedited feeding protocols starting 3-4 hours postprocedure, same-day discharge is now possible. The purpose of this study was to evaluate the safety and cost of image-guided percutaneous gastrostomy tube placement as an outpatient procedure.

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Objectives: The purpose of this study was to examine prognostic value of T1- and T2-mapping techniques in heart transplant patients.

Background: Myocardial characterization using T2 mapping (evaluation of edema/inflammation) and pre- and post-gadolinium contrast T1 mapping (calculation of extracellular volume fraction [ECV] for assessment of interstitial expansion/fibrosis) are emerging modalities that have been investigated in various cardiomyopathies.

Methods: A total of 99 heart transplant patients underwent the magnetic resonance imaging (MRI) scans including T1- (n = 90) and T2-mapping (n = 79) techniques.

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Purpose: To use structure-function cardiac MRI in the evaluation of relationships between donor and heart transplantation (HTx) recipient characteristics and changes in cardiac tissue structure and function. HTx candidates and donor hearts are evaluated for donor-recipient matches to improve survival, but the impact of donor and recipient characteristics on changes in myocardial tissue and function in the transplanted heart is not fully understood.

Materials And Methods: Cardiac MRI at 1.

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Purpose: To investigate the two-center feasibility of highly k-space and time (k-t)-accelerated 2-minute aortic four-dimensional (4D) flow MRI and to evaluate its performance for the quantification of velocities and wall shear stress (WSS).

Materials And Methods: This cross-sectional study prospectively included 68 participants (center 1, 11 healthy volunteers [mean age ± standard deviation, 61 years ± 15] and 16 patients with aortic disease [mean age, 60 years ± 10]; center 2, 14 healthy volunteers [mean age, 38 years ± 13] and 27 patients with aortic or cardiac disease [mean age, 78 years ± 18]). Each participant underwent highly accelerated 4D flow MRI (k-t acceleration, acceleration factor of 5) of the thoracic aorta.

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Background: Magnetic resonance tissue phase mapping (TPM) measures three-directional myocardial velocities of the left and right ventricle (LV, RV). This noninvasive technique may supplement endomyocardial biopsy (EMB) in monitoring grafts post-heart transplantation (HTx).

Purpose: To assess biventricular myocardial velocity alterations in grafts and investigate the relationship between velocities and acute cellular rejection (ACR) episodes.

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Objectives: The purpose of this study was to evaluate the sensitivity of multiparametric cardiac magnetic resonance imaging (CMR) for the detection of acute cardiac allograft rejection (ACAR).

Background: ACAR is currently diagnosed by endomyocardial biopsy, but CMR may be a noninvasive alternative because of its capacity for regional myocardial structure and function characterization.

Methods: Fifty-eight transplant recipients (mean age 47.

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Rationale And Objectives: Requests for gastrostomy tube placement in patients on aspirin (ASA) 325 mg are common, particularly in patients following reconstructive surgery for head and neck cancer, but periprocedural guidelines and recommendations regarding management of high dose aspirin are inconsistent. The purpose of this study was to assess the bleeding risk of percutaneous gastrostomy tube placement in patients on ASA 325 mg.

Materials And Methods: This retrospective study of 213 patients who underwent image-guided "push" percutaneous gastrostomy tube placement compared rates of significant bleeding and other secondary outcomes (including all-cause mortality within 30 days, procedure-related mortality, bowel perforation, abdominal abscess, peritonitis, aspiration pneumonia, intraprocedural airway complications, and tube dislodgement) between patients maintained on ASA 325 mg and patients not on antiplatelet or anticoagulation therapy.

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The assessment of both left (LV) and right ventricular (RV) motion is important to understand the impact of heart disease on cardiac function. The MRI technique of tissue phase mapping (TPM) allows for the quantification of regional biventricular three-directional myocardial velocities. The goal of this study was to establish normal LV and RV velocity parameters across a wide range of pediatric to adult ages and to investigate the feasibility of TPM for detecting impaired regional biventricular function in patients with repaired tetralogy of Fallot (TOF).

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Purpose: Late gadolinium enhancement cardiac MR (LGE-CMR) and extracellular volume fraction (ECV-CMR) are widely used to evaluate macroscopic and microscopic myocardial fibrosis. Macrocyclic contrast media are increasingly used off-label for myocardial scar assessment, given the superior safety profile of these agents. We aimed to assess the performance of two macrocyclic contrast agents, gadoterate meglumine and gadobutrol, for the evaluation of myocardial scar.

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Background: Following heart transplantation (Tx), recipients are closely monitored using endomyocardial biopsy, which is limited by cost and invasiveness, and echocardiography, which is limited regarding detailed structural and functional evaluation.

Purpose: To test the feasibility of comprehensive structure-function cardiac MRI as a noninvasive modality to assess changes in myocardial structure and function.

Study Type: Prospective.

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Objectives: Free-breathing real-time (RT) imaging can be used in patients with difficulty in breath-holding; however, RT cine imaging typically experiences poor image quality compared with segmented cine imaging because of low resolution. Here, we validate a novel unsupervised motion-corrected (MOCO) reconstruction technique for free-breathing RT cardiac images, called MOCO-RT. Motion-corrected RT uses elastic image registration to generate a single heartbeat of high-quality data from a free-breathing RT acquisition.

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Purpose: To assess the performance of highly accelerated free-breathing aortic four-dimensional (4D) flow MRI acquired in under 2 minutes compared to conventional respiratory gated 4D flow.

Methods: Eight k-t accelerated nongated 4D flow MRI (parallel MRI with extended and averaged generalized autocalibrating partially parallel acquisition kernels [PEAK GRAPPA], R = 5, TRes = 67.2 ms) using four k -k Cartesian sampling patterns (linear, center-out, out-center-out, random) and two spatial resolutions (SRes1 = 3.

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The purpose of this study was to identify the 100 top-cited articles in the radiology of trauma, analyze the resulting database to understand factors resulting in highly cited works, and establish trends in trauma imaging. An initial database was created via a Web of Science (WOS) search of all scientific journals using the search terms "trauma" and either "radiology" or a diagnostic modality. Articles were ranked by citation count and screened by two attending radiologists plus a tiebreaker for appropriateness.

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Article Synopsis
  • Triple-negative breast cancers (TNBC) are a subgroup of breast cancers that lack key hormone receptors and occur more frequently in African American women, making up about 15% of all breast cancer cases.
  • The poor outcomes for TNBC patients are partly due to the absence of effective therapeutic targets; although the epidermal growth factor receptor (EGFR) is overexpressed in many TNBC cases, current EGFR inhibitors have limited success in treating metastatic cases.
  • Research has shown that combining mTOR inhibitors, like rapamycin, with EGFR inhibitors, such as lapatinib, enhances treatment effectiveness by increasing cancer cell death and reducing tumor growth, suggesting this combination therapy could potentially improve outcomes for certain TNBC patients.
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In this study, cattle manure was converted to bio-oil by subcritical hydrothermal liquefaction in the presence of NaOH. The effects of conversion temperature, process gas, initial conversion pressure, residence time and mass ratio of cattle manure to water on the bio-oil yield were studied. The bio-oil was characterized in terms of elemental composition, higher heating value, ultraviolet-visible (UV/Vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS).

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Structural health monitoring has been used successfully to identify defects in civil infrastructure and aerospace applications. Given that the majority of low back pain is thought to be mechanical in nature, our objective was to determine if structural health monitoring techniques could be employed successfully to identify the presence, location and magnitude of structural alterations within the spine. In six eviscerated cadaveric pigs, bone screws were drilled into the anterior bodies of L1-L5 and tri-axial accelerometers fixed to each spinous process.

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As the majority of back pain is thought to be mechanical in origin, quantitative tests designed to assess spinal mechanics may provide information about its etiology and treatment. This paper describes the application of structural vibration testing in the spine, its reliability and ability to discriminate between different structural states. In each of five cadaveric pigs, tri-axial accelerometers were fixed to the spinouses of L1-5 and short-duration vibrations (0-2000Hz) were applied to the L3 spinous exclusively.

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